9th IPWSO Conference | 1

1.1 - The role of MAGEL2 and interacting partners in neurobehavioral phenotypes
Michael D. Fountain,1,2,3, Christian P. Schaaf1,2,3
1Interdepartmental Program in Translational Biology and Molecular Medicine, 2Department of
Molecular and Human Genetics, Baylor College of Medicine; 3Jan and Dan Duncan NeurologicalResearch Institute, Texas Children’s Hospital
Background: The maternally imprinted, paternally expressed MAGEL2 gene (affected only wheninherited from the father, unaffected when inherited from the mother) located in the Prader-Willi
critical region 15q11-13 was recently reported as the first single gene responsible for Prader-Willi
syndrome (PWS) and Prader-Willi-like phenotypes. Preliminary studies identified four individuals
with truncating mutations in MAGEL2, expressing hypotonia, feeding difficulties, and intellectual
disability. A diagnosis of autism spectrum disorder (ASD) was also described. While these patients
resemble PWS, they are also phenotypically distinct from classic PWS. As such, the syndrome caused
by MAGEL2 point mutations has been renamed from Prader-Willi-like syndrome to Schaaf-Yang
syndrome (SHFYNG) (OMIM #615547).
Methods and Results, I: Since the time of this first publication, we have identified 40 new individuals
with Schaaf-Yang syndrome from 14 families, including one family with a total of 15 affectedindividuals across two generations. All cases harbor truncating mutations of MAGEL2, and nucleotidesc.1990-1996 arise as a mutational hotspot, with 10 individuals and one fetus harboring a c.1996dupC(p.Q666fs) mutation and two fetuses harboring a c.1996delC (p.Q666fs). The phenotypic spectrum of
Schaaf-Yang syndrome ranges from fetal akinesia to individuals with hypotonia, feeding difficulties
requiring assisted feeding, hypogonadism, contractures, DD/ID, ASD, and a characteristic behavior
profile, among others.
Conclusions, I: These findings provide strong evidence for the pathogenicity of truncating mutationsof the paternal allele of MAGEL2.
Methods and Results, II: To elucidate the role of MAGEL2 interactors, we investigated the functional
network of MAGEL2, and identified the USP7 protein to be a direct interactor of MAGEL2, criticallyimportant for endosomal protein recycling. Database queries identified seven patients with de novo
heterozygous loss-of-function variants, including six contiguous, non-synonymous deletions including
USP7, and one likely pathogenic nonsense variant of USP7. The patients’ clinical phenotypes involved
developmental delay/intellectual disability, ASD, seizures, hypogonadism, hypotonia, and aggressive
behavior.
Conclusions, II: These findings suggest a molecular and clinical spectrum of disorders, whichhighlights the important role of MAGEL2 and USP7 in human neurodevelopment.
Summary: Prader-Willi syndrome, Schaaf-Yang syndrome, and USP7-associated disorder represent a
molecular and clinical spectrum of human neurodevelopmental diseases. Our findings lead us tohypothesize that other genes encoding for proteins involved in WASH ubiquitination and endosomal
actin assembly are candidate genes for related neurodevelopmental disorders. As technology
progresses and more affected individuals are being identified, the clinical and molecular signatures ofthe various disorders will become increasingly clear.

4 | 9th IPWSO Conference1.2 - A novel cost-effective screening test for abnormal FMR1/SNRPN methylation insymptomatic children and newborns.
David E Godler,1# Xin Li, 1 Yoshimi Inaba,1 Quang M Bui, 2 David Francis, MS,1 David J Amor, 1,3
Justine Elliot,3 Tiffany Wotton,4 Jonathan Cohen,5 Carolyn Rogers,6 Mike Field,6 Howard R Slater. 1,3
	  1

Victorian Clinical Genetics Services and Murdoch Childrens Research Institute, Royal Children’s Hospital,
Melbourne, Victoria, 3052, Australia; 2Centre for Molecular, Environmental, Genetic and Analytic
Epidemiology, University of Melbourne, Carlton, Victoria, 3053, Australia; 3Department of Paediatrics,
University of Melbourne, Melbourne Victoria, 3052, Australia; 4New South Wales Newborn Screening
Program, Children's Hospital at Westmead, Sydney, Australia; 5Fragile X Alliance Inc, and Centre forDevelopmental Disability Health Victoria, Monash University, Melbourne, Australia; 6Genetics of Learning
Disability Service, Hunter Genetics, Waratah, New South Wales, Australia

Background: This study describes a novel low cost quantitative methylation test named Methylation
Specific Quantitative Melt Analysis (MS-QMA), and its use for combined screening of epi-mutations
associated with fragile X syndrome and chromosome 15 imprinting disorders in symptomatic children
and newborns. The test targets FMR1 and SNRPN promoters, with the lower limit of detection forabnormal methylation of 1%. Methods and Results: MS-QMA FMR1 assay was performed on lysate(without DNA extraction) from a single 3 mm punch per newborn screening dried blood spot.
Sensitivity and specificity were >99% for fragile X syndrome full mutation (FM) alleles (30 FM males;
25 FM females; 89 male controls; 95 female controls); for Prader-Willi syndrome (PWS) andAngelman syndrome (AS) these were 100% (17 PWS, 12 AS, 42 controls, all confirmed by microarray and MS-PCR) using venous blood DNA. As expected, there was no significant difference
between SNRPN methylation in the PWS and AS groups for those diagnosed at birth (n=15) and thosediagnosed at >1 year of age (n=14). Furthermore, the SNRPN assay performed equally well withnewborn blood spot lysates (n=11) and venous blood DNA collected at birth. In a separate cohort of
DNA samples retrospectively collected from 57 patients referred for chromosome 15 imprinting
disorder testing, MS-QMA identified 14 abnormal cases (8 PWS - 100% methylated; 3 AS - 0%
methylated; 3 Chromosome 15 duplication syndrome - 72% (+/-2%) methylated; with control range 4457%). These were all consistent with the MS-MLPA and micro-array results. MS-QMA also identified
4 patients (normal by MS-MLPA and micro-array), referred with obesity and developmental delay,with abnormal 63-66% SNRPN methylation and 2 patients with 38% methylation, suggestive ofmosaicism for PWS and AS, respectively.
Conclusions: FMR1/SNRPN MS-QMA may be a cost-effective approach with enhanced analytical anddiagnostic sensitivity that is suitable for testing and screening for four early onset epigenetic disorders
with overlapping cognitive and behavioural phenotypes.
Summary: We have developed a highly sensitive, cost-effective test for symptomatic children andasymptomatic newborns that can be effectively used to simultaneously screen for DNA changes
associated with Prader-Willi syndrome, and three other common childhood disorders.

9th IPWSO Conference | 5

1.3 - Energy expenditure, physical activity and maximal oxygen uptake in adults with Prader–
Willi syndrome
Itai Gross*1 , Harry J Hirsch*2,3 , Naama Constantini4 , Shachar Nice4 , Yehuda Pollak5 , Larry
Genstil2,3 , Talia Eldar- Geva2,6,7 and Varda Gross Tsur2,3,6
1

Department of Pediatrics, Hadassah Medical Center, Ein Kerem, Jerusalem, Israel, 2Israel
Multidisciplinary Prader-Willi Syndrome Clinic, Neuropediatric Unit, Department of Pediatrics, Shaare
Zedek Medical Center, Jerusalem, Israel, 3Neuropediatric Unit, Department of Pediatrics, Shaare Zedek
Medical Center, Jerusalem, 4Sports Medicine Center, Department of Orthopedic Surgery, Hadassah
Medical Center, Hebrew University Medical Center, Jerusalem, Israel, 5The School of Education,
Hebrew University, Jerusalem, Israel, 6The Hebrew University Faculty of Medicine, Jerusalem, Israel,
7
Reproductive Endocrinology and Genetics Unit, Department of Obstetrics and Gynecology, Shaare
Zedek Medical Center, Jerusalem, Israel*These authors contributed equally to this work.
Background: Prader-Willi Syndrome (PWS) is the most common syndromal cause of life threatening
obesity. Strict adherence to a low-calorie diet and regular physical activity prevent extreme obesity.
Unexpectedly, direct measurement of maximal oxygen uptake (VO2 max), the “gold standard” forassessing aerobic exercise capacity, has not been described in PWS. The objective of this study was toassess aerobic capacity by direct measurement of VO2 max in adults with PWS, and in age and BMImatched controls (OC). Compare the results with values obtained by indirect prediction methods.
Methods and results: 17 individuals (12 males) ages: 19-35 (28.6±4.9), BMI: 19.4-38.1 (27.8±5) kg/m2
with genetically confirmed PWS who exercise daily and 32 matched OC (22 males) ages: 19-36 (29.3±5.2), BMI: 21.1-48.1 (26.3±4.9) kg/m2. All filled out a medical questionnaire and performed strengthand flexibility tests. During a graded exercise test on a treadmill VO2 max was determined bymeasuring oxygen consumption. VO2 max (24.6±3.4 vs 46.5±12.2 ml/kg/min, p<0.001) and anaerobic
threshold (20±2 and 36.2±10.5 ml/kg/min, p<0.001), maximal strength of both hands (36±4 vs.
91.4±21.2 kg, p<0.001) and flexibility (15.2±9.5 vs. 26±11.1 cm, p=0.001) were all significantly lower
for PWS compared to OC.
Conclusions: Aerobic capacity, assessed by direct measurement of VO2 max, is significantly lower in
PWS adults, even in those who exercise daily, compared to OCs. Indirect estimates of VO2 max are
accurate for OC, but unreliable in PWS. Direct measurement of VO2 during a graded exercise test ispreferred, when tailoring a personal training plan.
Summary: Effective exercise is an essential part of treatment for individuals with PWS. We
documented that aerobic capacity is much lower in PWS adults when compared to OCs and that direct
calculations of aerobic capacity are needed when planning clinical studies or individual plan of exercise
in PWS.

6 | 9th IPWSO Conference1.4 - Causes of deaths in French patients with Prader-Willi syndrome
P Lemoine1, C Arnaud2, G Diene1, C Molinas1, M Tauber1
1Centre de Référence pour le Syndrome de Prader-Willi; Hôpital des Enfants, 330 avenue de Grande
Bretagne, TSA70034, 31059 Toulouse cedex 9, France
2
INSERM UMR 1027-Université Toulouse III Hôpital Paule de Viguier, Toulouse, France
Background: Death reports are a critical issue in Prader-Willi syndrome (PWS). We published a study
analyzing the causes of death in children with PWS reported in the literature in 2008. Our objective is
now to identify the number and to describe the causes of death in children and adults with PWS.
Methods and Results: We conducted a retrospective study from 2004 to 2012 collecting deathcertificate with a notification of CIM-10 « Q87.1 » from the national death register: Centre of
Epidemiology on the Causes of Death in France (CépiDC). In addition we contacted the 22 competence
centres for PWS in France. We identified 85 patients, including 12 children, with a mean age 29 years[0-58] and a sex ratio (M/F) of 46/39. We then classified the deaths depending on causes: we found 41(48.2%) respiratory causes (infection, respiratory insufficiency or cardiorespiratory), 8 (9.4%) nonrespiratory infections (gastroenteritis, other infection), 10 (11.7%) cardiac events (pulmonary
embolism, cardiac insufficiency, other cardiac event), 15 (17.7%) sudden deaths, 1 (1.2%) foodchoking during feeding, 1 (1.2%) accident and 4 (4.7%) other causes. There was no notification for 5
patients (5.9%). Of note when cardiorespiratory arrest was notified without other precision weclassified the death as sudden death.
Conclusions: Our data documented the younger age at death in PWS 31 years vs. 73 years in thegeneral population. The first cause of death is respiratory failures representing 48.2% in PWS vs. 6% in
the general population. Thirty three % of children died from respiratory failure vs. 50.6% in adults. The
second cause is sudden death 17.7% (25% in children and 16.4% in adults) and the third cause is
cardiac 11.7% (8.3% in children and 12.3% in adults). Prospective studies are required in different
countries in order to describe more precisely the causes of deaths and implement specific prevention
strategies.
Summary: we investigated the number of death reports 2004 to 2012 in the French PWS population andclassified the different causes of death in children and adults with PWS.
	  9th IPWSO Conference | 7

2.1 - Characterizing the processing, localization, and function of Snord116 noncoding RNAs at
the Prader-Willi locus
Rochelle Coulson, Dag Yasui, Justin Aflatooni, Quang Ha, Janine LaSalle
Medical Microbiology & Immunology, Genome Center, M.I.N.D. Institute, University of California,
Davis, CA, USA.
BackgroundThe noncoding RNA cluster SNORD116, located within the Prader-Willi critical locus at 15q11-13 isGC-skewed, resulting in R-loop formation, histone displacement, and chromatin decondensation
specifically of the paternal allele upon neuronal transcription. SNORD116 processing produces two
noncoding RNAs: SNORD116 snoRNAs, which localize to the nucleolus of maturing neurons, and 116
host gene (116HG), which is retained within the nucleus, localizing to its paternally decondensed siteof transcription and forming an RNA cloud.
Methods and Results
To understand the processing, localization, and functional relevance of each component of SNORD116,
we engineered novel transgenic mice to test complementation of the PWS mouse model, Snord116del.
Complete transgene wild-type (Ctg/WT) mice carrying all of the elements of the Snord116 repeat weregenerated and bred to Snord116del males to produce mice deficient for endogenous paternal Snord116
but expressing the transgene (Ctg/Snord116del). RNA fluorescence in situ hybridization (FISH)
analysis of brain showed that spliced 116HG RNA localized in a distinct cloud at its decondensed
transcription site and mature snoRNAs localized to the nucleolus in wild-type (WT) but not
Snord116del neurons. In non-neuronal Ctg/WT tissues and all Ctg/Snord116del tissues, no 116HG
RNA cloud or snoRNAs were detected, but in Ctg/WT neurons, nucleolar snoRNAs were increased anda significantly larger single 116HG RNA cloud was detected. RT-PCR analysis demonstrated thatsplicing of the Snord116 transgene was largely restricted to neuronal tissues of both Ctg/WT and
Ctg/Snord116del mice, despite widespread expression from the CMV promoter in many tissues.
Rbfox3 (NeuN), a neuronal specific splicing factor was tested for its role in Snord116 splicing by
siRNA knockdown in neurons derived from Ctg/Snord116del NPCs. Rbfox3 knockdown reduced
spliced Ctg transcript levels without affecting the abundance of the primary transcript.
Conclusions
These results suggest that processing of the Snord116 transcript is dependent on neuronal-specificsplicing factors including Rbfox3 and/or chromatin states, particularly the decondensed Snord116
paternal allele. Analyses of a spliced 116HG/Snord116del transgenic mouse is in progress to determine
whether the process of splicing facilitates localization or whether providing a pre-spliced transcript
circumvents the need for an endogenous active Snord116 locus.
Summary: The Snord116 gene was inserted into the genome of a mouse model for Prader-Willi
syndrome, in which mice lack a paternal copy of this gene. In wildtype mice, this extra copy
contributes to the RNA products typically produced, however in the Prader-Willi mice, no mature
products of the Snord116 gene are detected. Based on our results, this appears to be due to the brain
specific protein Rbfox3, which is required for processing of Snord116 products, as well as the structureof the DNA at the original paternal location.

8 | 9th IPWSO Conference2.2 - Ghrelin acylation by ghrelin O-acyltransferase:
A potential target to treat hyperphagia in Prader-Willi syndrome
James L. Hougland, Joseph E. Darling, Kayleigh R. McGovern, and Elizabeth R. Cleverdon
Department of Chemistry, Syracuse University, Syracuse, NY

Background: Obesity and hyperphagia present two major health threats to patients with Prader-Willi
syndrome (PWS). The discovery of the hormone ghrelin and its role in controlling appetite suggests a
potential role for ghrelin in PWS. Elevated levels of ghrelin in children and adults with PWS, coupledwith ghrelin’s role in stimulating appetite, highlights inhibition of ghrelin signaling as a potential
treatment avenue for PWS-associated hyperphagia. Recent studies have demonstrated high ghrelinlevels in the early postnatal period can lead to life-long metabolic disturbances, providing further
support for ghrelin as a therapeutic target in PWS. Ghrelin requires a unique chemical modification(octanoylation) catalyzed by the enzyme ghrelin O-acyltransferase (GOAT) to bind and activate its
receptor. Ghrelin is the only predicted substrate for GOAT within the human proteome, supporting
inhibition of GOAT-catalyzed ghrelin acylation as a specific and targeted avenue to treat healthconditions potentially impacted by ghrelin signaling such as hyperphagia in PWS patients.
Methods and Results: Our research focuses on understanding the substrate specificity and catalytic
mechanism of GOAT, working towards development of GOAT inhibitors. Through structure-activity
analysis of both GOAT substrates and inhibitors, we have identified multiple sites within ghrelin
involved in substrate recognition by GOAT. Targeted mutagenesis studies coupled with functional
studies offer insight into the location of the active site and substrate binding sites within GOAT andsuggest potential catalytic mechanisms. Using rational approaches and small-molecule library
screening, we have identified several new classes of GOAT inhibitors for optimization to realize
increased potency and bioavailability. Several of these molecules may serve as mechanism-based
inhibitors, the first such examples identified for GOAT.
Conclusions: Defining interactions used by hGOAT to bind, recognize, and modify ghrelin offers new
insight into the structure of the hGOAT active site and has guided the design, identification, andoptimization of hGOAT inhibitors. Development of these hGOAT inhibitors is an essential step
towards evaluation of ghrelin signaling as a route for treating hyperphagia in PWS.
Summary: The protein hormone ghrelin plays a key role in controlling appetite. Patients with PWS
have high levels of ghrelin in their bloodstreams, suggesting the voracious appetite that accompanies
PWS may arise from excessive ghrelin signaling. Ghrelin O-acyltransferase (GOAT), an enzyme that
activates ghrelin, offers a target for specifically blocking ghrelin activity. By using biochemistry andsynthetic chemistry to understand how GOAT binds and activates ghrelin, we are learning how tocreate molecules that block ghrelin activation by GOAT. These new GOAT inhibitors are essential forevaluating ghrelin’s potential as a therapeutic avenue for treating hyperphagia in patients with PWS.

9th IPWSO Conference | 9

2.3 - Knockout of the zinc finger protein ZNF274 in PWS-specific stem cell neurons activates
expression of repressed maternal 15q11.2-q13 transcripts
Maeva Langouet, Heather Glatt-Deleey, Erin Banda, Chris Stoddard, Elodie Mathieux, Leann Crandall,Marc Lalande
Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut,
Farmington CT
Background
Prader-Willi syndrome (PWS, MIM 176270) is characterized by neonatal hypotonia and failure to
thrive during infancy, and, subsequently, by obesity, hyperphagia, cognitive disability and behavioral
abnormalities. Hypothalamic dysfunction is hypothesized to be responsible for many of the PWS
features. This neurobehavioral disorder of genomic imprinting is caused by the lack of expression ofgenes on the paternally inherited chromosome 15q11.2-q13 region. The detailed genetic basis of PWS
is complex involving the loss of active copies of a cluster of non-coding box C/D class small nucleolar
RNAs, the SNORD116 snoRNAs.
Methods and Results
We have generated stem cell models of PWS via induced pluripotent stem cell technology and used
these to identify a new complex that is involved in silencing the maternal copy of the PWS criticalregion (PWS-CR) encompassing the SNORD116 cluster. This epigenetic complex is composed of thezinc-finger protein ZNF274 and the SET domain, bifurcated 1 (SETDB1) histone H3 lysine 9 (H3K9)
methyltransferase. Here, using genome editing approaches, we have knocked out ZNF274 expressionin PWS-specific iPSC lines from multiple PWS patients with diverse genetic abnormalities (large
deletion, small deletion and UPD) and showed that the extent of transcriptional re-activation of PWSCR genes varies during in vitro neurogenesis. While PWS-CR gene expression in ZNF274 knockout(KO) iPSCs is ~5 % of normal levels, wild-type mRNA levels are completely restored in neurons
derived from PWS ZNF274 KO iPSCs. Surprisingly, the DNA methylation at the PWS-IC remains
unchanged upon ZNF274 KO, suggesting that the ZNF274 complex acts as a second imprinting locus
regulating the PWS-CR gene expression during the course of neurogenesis.
Conclusions
Our data further support the finding that ZNF274 may represent a potential target for future therapeutic
applications to rescue the PWS phenotype.
Summary
Our team has discovered a component of the switch off mechanism leading to the parent-of-origin
specific gene expression in the 15q11.2-q13 region: a protein called ZNF274 that specifically binds thematernal SNORD116 cluster. By targeting ZNF274 for destruction (genetic knock out or KO) in stem
cells created from PWS skin cells, we have reversed the off-switch and turned on the maternal
chromosome 15 set of genes. Importantly, we demonstrated that the rescue is maintained during thecourse of neuronal differentiation, opening novel opportunities for potential therapeutic interventions in
PWS.

10 | 9th IPWSO Conference2.4 - Mechanisms of hormone secretion deficits in Prader-Willi syndrome (PWS)
Marie A. Johnson1, Peter Drain2, Dale W. Lewis3, Meryl G. Warshafsky1, Patrizia Luppi2, Susanne M.
Gollin3, and Robert D. Nicholls1
1
2

Division of Medical Genetics, Department of Pediatrics, Children’s Hospital of Pittsburgh of UPMC;
Department of Cell Biology, and 3Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA.

Background: PWS is a multisystem disorder caused by loss of function of a cluster of ~12 paternallyexpressed, imprinted genes in human chromosome 15q11.2. Neonatal failure to thrive (FTT) is
followed by childhood-onset hyperphagia, obesity, neurocognitive and behavioral issues, and deficits ingrowth hormone (GH), gonadotropin-releasing hormone (GnRH), and other hormones. These clinicalfeatures are assumed to arise from hypothalamic deficits. In contrast, using a mouse model with adeletion of the orthologous cluster of PWS-imprinted genes, we have shown that FTT is associatedwith fetal pancreatic endocrine abnormalities and a postnatal onset of severe hypoglycemia.
Mechanisms contributing to this phenotype included a developmental defect with increased islet-cell
apoptosis and reduced β- and α-cell mass, deficient basal and glucose-stimulated insulin secretion
leading to hypoinsulinemia, and concurrent hypoglucagonemia with lack of a counter-regulatory
response to hypoglycemia. These mice had upregulated expression of genes encoding pancreatichormones and proteins involved in hormone secretion; however, this was insufficient to overcome thehormonal deficits. Indeed, a similar metabolic profile with hypoglycemia is seen in PWS. Thesefindings indicate that PWS-imprinted genes are required for the prevention of hypoglycemia as well as
the development, survival, and secretory function of pancreatic endocrine cells. Based on the mouse
data implicating defective maturation or exocytosis of insulin secretory granules (SGs), we hypothesizethat PWS genes are required for secretory function of pancreatic and neuroendocrine cells including forinsulin, glucagon, GnRH, GHRH or GH, and other hormones (e.g., oxytocin).
Methods/Results: To establish hormone-secreting cell models, we utilized CRISPR/Cas9 genome
editing within rodent cell lines that specifically secrete high levels of GnRH or insulin, the latter also
expressing an mCherry fluorescent protein-propeptide hormone biosensor to monitor trafficking withinSGs. Initial transfections with pairs of gRNAs and Cas9 vectors led to ~10% of cells with a deletion ofthe ~3.16 Mb PWS-orthologous imprinted domain. Subsequently, we generated isogenic, clonal PWSdeletion and control cell lines based on deletion-PCR of genomic DNA, and are currently completing
molecular cytogenetics, gene expression and hormone secretion assays, and examining SG maturationand exocytosis.
Conclusions: We have developed pancreatic and neuroendocrine cells with deletions of PWSimprinted genes, as a model system to identify which PWS-imprinted genes control secretion ofmultiple hormones and the molecular, biochemical, and cellular mechanisms involved.
Summary: This study will identify which PWS genes regulate secretion of which hormones and how,
and could lead to new hormone or small molecule treatment approaches to supplement the benefits
provided by GH for individuals with PWS (or similar endocrine and metabolic defects).

9th IPWSO Conference | 11

2.5 - Identification and mechanistic studies of a novel PWS-associated gene
Yi-Heng Hao1, Michael Fountain Jr3, Christian P. Schaaf3, and P. Ryan Potts1,21

Dept. of Physiology, UT Southwestern Medical Center, Dallas, TX 75390 2Dept. of Cell andMolecular Biology, St. Jude Children’s Research Hospital, Memphis, TN 38120 3Translational
Biology and Molecular Medicine, Baylor College of Medicine, Houston, TX 77030

Background: The MAGE-L2 gene is in the Prader-Willi Syndrome (PWS) susceptibility locus and isdeleted or mutated in individuals affected with PWS or Schaaf-Yang syndrome. Furthermore, MAGEL2 knockout mice phenocopy several aspects of PWS. Recently, my group has uncovered the cellularfunction of MAGE-L2. We showed that MAGE-L2 functions with the TRIM27 E3 ubiquitin ligase topromote recycling of membrane proteins from endosomes back to the plasma membrane or the transGolgi network, thus sparing them from lysosomal degradation. It does so through ubiquitination andactivation of the actin nucleating protein WASH on endosomes. However, it has remained unclear how
MAGE-L2 is regulated.
Methods and Results: Utilizing a number of different biochemical and cell biological assays, we haveidentified a novel interacting partner of MAGE-L2, the USP7 deubiquitinating enzyme. We show that
MAGE-L2-TRIM27 stably associates with USP7 where USP7 is essential for two critical aspects of
MAGE-L2 function. First USP7 protects TRIM27 from auto-ubiquitination and proteosomal
degradation. Second, USP7 regulates ubiquitination of the MAGE-L2-TRIM27 substrate, WASH, toproperly tune the amount of endosomal actin and control the endosomal protein recycling pathway.
Depletion of USP7 impairs the MAGE-L2-regulated endosomal protein recycling pathway in cells.
Importantly, we identify de novo heterozygous loss-of-function mutations of USP7 in individuals witha neurodevelopmental disorder whose symptoms overlap with children with MAGE-L2 mutation,
including intellectual disability, autism spectrum disorder, and hypotonia.
Conclusion: USP7 is a novel component of the MAGE-L2-TRIM27 ubiquitin ligase complex and isnecessary to allow proper regulation of WASH ubiquitination and endosomal actin accumulation andprotein recycling. Furthermore, we identify individuals with mutation in USP7 that have overlapping
symptoms to those with mutation of MAGE-L2. These results provide unanticipated insights into
endosomal trafficking, illuminate the cooperativity between an ubiquitin ligase and a deubiquitinating
enzyme, and establish a role for USP7 in human neurodevelopmental disease.
Summary: We have uncovered the cellular function of the PWS-associated gene, MAGE-L2. MAGEL2 functions to facilitate proper cellular protein homeostasis by controlling protein trafficking anddegradation. Furthermore, we identify a MAGE-L2 interacting protein, USP7, which collaborates with
MAGE-L2 in this cellular process and is also mutated in children with symptoms similar to MAGE-L2
mutation.

12 | 9th IPWSO Conference2.6 - Function and therapeutic substitution of snoRNAs in Prader-Willi syndrome
Zhaiyi Zhang, Marina Falaleeva and Stefan Stamm
University of Kentucky, Lexington, KY, USA
Background
The Prader-Willi critical region contains five C/D box snoRNAs (SNORDs) (107, 109, 64, 115 and116) that are not expressed in PWS patients. The 47 copies of SNORD115 are almost identical andregulate alternative splicing of the serotonin receptor 2C pre-mRNA, where they promote the formationof the full-length, active receptor. In contrast, no functions and possible targets of the other SNORDs
are known. The 29 SNORD116 copies are more diverse than SNORD115 and fall into five classes ofhigher sequence identity. Loss of SNORD116 results in a Prader-Willi like phenotype, underlining theimportance this SNORD.
Method and Results
We devised a method to knock-down SNORDs using antisense oligos composed of nucleotides withdifferent chemistry. Using five different oligos, we knocked-down all SNORD116 copies in theneuroblastoma cell line SH-SY5Y. RNAseq of these samples revealed that SNORD116 promotes theinclusion of 51 exons, about 19 or which are microexons. The microexons are less than 50 nt in lengthand keep the reading frame. Most of them are located near or in known protein domains. The effect of
SNORD116 on most individual exons is small (<50%), but most exons are located in proteins that
affect vesicle transport. Bioinformatic predictions show short sequence complementarities between
SNORD116 and target exons. When nuclear extract is fractionated under native conditions andseparated using glycerol gradients, about 30% of SNORD116 purifies in fractions devoid of fibrillarin
and affinity purification of SNORD116 reveals its association with hnRNPs. This suggest that
SNORD116 forms atypical SNORD-protein complexes and regulates proteins involved in vesiculartransport via direct RNA:RNA interaction.
We previously developed an oligonucleotide that promotes alternative exon inclusion of the serotoninreceptor 2C and could thus substitute the loss of SNORD115. Systemic injection of the oligo results inmarked decrease of food uptake in mice. To explain this effect we re-analyzed serotonin receptor 2C
expression in mouse tissues and found expression in the pituitary where the oligo rapidly promotes
exon inclusion. Both SNORD115 and SNORD116 are expressed in pituitary, suggesting that they
regulate vesicular trafficking and receptor localization in this tissue.
Conclusions
The SNORDs with the strongest expression missing in PWS, SNORD116 and SNORD115 all act inpromoting alternative exons that work in vesicular transport and serotonin receptor 2C
localization/function. Their expression in the pituitary suggests a role of this gland in PWS.
Summary
SNORD116 and SNORD115 possibly regulate vesicle transport and serotonin receptor 2C activity inthe pituitary, which could explain some of the hormonal deregulations in PWS. The SNORDs can besubstituted with oligonucleotides, suggesting that oligo delivery through injections could be atherapeutic avenue to treat PWS.

9th IPWSO Conference | 13

3.1 - Aberrant, autistic, and food-related behaviors in adults with Prader-Willi syndrome:
The effects of age and genotype
Hiroshi Ihara, MD, PhD1, Hiroyuki Ogata, MA1,2, Masao Gito, MD1,2,3, Masayuki Sayama, MA1,
Nobuyuki Murakami, MD, PhD4, Tadayuki Ayabe, MD, PhD4,5, Yuji Oto, MD, PhD4, Toshiro Nagai,
MD, PhD4,6, Kazutaka Shimoda, MD, PhD2
1Department of Psychiatry, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan; 2Department of

Psychiatry, Dokkyo Medical University School of Medicine, Tochigi, Japan; 3Ikezawa Hospital, Saitama, Japan;
4Department of Pediatrics, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan; 5Department of
Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo, Japan;
6Nakagawanosato Ryoiku Center, Saitama, Japan

Background: This study aims to explore the difference of age as well as genotype in regards to theseverity of behavioral symptoms in Prader-Willi syndrome (PWS), with special emphasis on thecomparison between young adults and adults.
Methods and Results: The Food Related Problem Questionnaire (FRPQ), the Aberrant Behavior
Checklist Japanese Version (ABC-J), and the Pervasive Developmental Disorders Autism Society
Japan Rating Scale (PARS) were administered to 45 PWS patients. The participants consisted of 33
young adults (ages 18 to 28) and 12 adults (ages 30 to 45), including 23 young adults and 11 adults
confirmed as having a paternal chromosome 15q deletion (DEL), and 10 young adults and one adultconfirmed as having maternal uniparental disomy (mUPD) of chromosome 15. To examine that thedifference between young adults and adults have on the symptom’s severity, Mann-Whitney U tests
were conducted. Statistically significant differences were found in ABC-J (p=.035) and PARS
(p=.049), with higher scores in young adults than adults. Such differences between the two age groups
were still true for DEL subgroups (ABC-J: p=.022; PARS; p=.038). By contrast, there was no
significant difference between young adults and adults regarding FRPQ (p=.79).
Conclusions: In the total PWS patients, aberrant behaviors and autistic behaviors in young adults weremore severe than those in adults. Even in DEL subgroups aberrant behaviors were more severe inyoung adults. In terms of food-related behaviors, no significant differences were found between young
adults and adults. These results suggest that aberrant behaviors and autistic behaviors decline fromaround the ages of thirty, while food-related behaviors give no indication of diminishing in spite ofdevelopmental growth. Hyperphagia should be considered to follow a developmental trajectory
independent from that of other behavioral symptoms in PWS such as aberrant and autistic
symptomatology.
Summary: In PWS patients aberrant and autistic behaviors decline around the ages of thirty.

14 | 9th IPWSO Conference3.2 - The PRASOC project: Assessment of the impact of cognitive, executive and emotional
abilities on the difficulties of adaptation and socialization of patients with Prader-Willi
Syndrome, preliminary results
V. Postal1, A-M. Camblats1, J. Chevalère1, J. Jauregui2-3, V. Laurier3, J. Tricot3, D. Thuilleaux3, C.
Bellamy4, M. Glattard4 , F. Besnier5 & M. Tauber4
1

Univ. Bordeaux, Laboratoire de Psychologie EA 4139, Bordeaux, France, 2EuskalHerriko
Unibertsitatea, San Sebastián, Spain, 3AP-HP Hôpital Marin, Hendaye, France, 4 CHU Toulouse,
France, 5 French Prader Willi Association
Background: While behavioural descriptions and recommendations in terms of diagnosis andmanagement are relatively documented (cf. National protocol of diagnosis and care for rare diseases,
HAS, 2012), the specific cognitive and emotional disorders and their incidence on the daily lives ofindividuals with PWS are still poorly understood. Intellectual deficit cannot completely explain most of
the daily difficulties observed in people with PWS. Our recent studies showed that patients with PWS
exhibit an executive deficit, in part independent of intellectual level. (Chevalere et al, 2013; 2015). In
addition, the emotional component seems to be an important factor involved in cognitive treatments
and relationships with others. Few studies so far have reported the main influence of emotions in
performing executive tasks in PWS. Finally, as disturbed eating behaviour is a central feature of PWS,
it appears essential to study the physiological and behavioural reactions of patients when confronted
with food.
Methods and Results: The project PRASOC (Prader-Willi Socialization) is a French multicentricresearch program which implies a laboratory of Psychology, two reference centers of PWS (adults andchildren) and the French Association of Prader-Willi. The objective is to provide a precise descriptionof the executive and emotional capacities linked with food at various ages. We presented thepreliminary results about the executive functioning in association with emotional components. We
interested about inhibition, working memory updating and flexibility capacities assessed by laboratory
cognitive tasks applied to children (N=32 , m= 11.14) and adults (N=37, m=30.0) compared with twocontrol groups, one matched to chronological age and another to biological age. The results show thatin spite of a global impairment of executive functions, some of them seems not be impaired or at least
not specific to the PWS but linked with the intellectual level. Moreover, it is quite surprising to notethat the processing of emotion is not systemically impaired in the PWS and that the relationship withfood seems not to modify the processing of information.
Conclusion: The study sheds light on the executive capacity of people with SPW and their relationshipwith emotional component from childhood to adulthood. Some deficits seem linked with intellectuallevel but some difference indicated that some capacities are similar to the control population (especiallyfor the adults) and others tend to be more similar with impaired intellectual people.
Summary: The first results of a research program in cognitive psychology are presented. By comparing
two groups of participants with PWS (children and adults) with a group matched by age without deficit
and another group matched by age with the same intellectual deficit than the PWS group, we began tohave a more precise description of the cognitive capacities of the PWS and especially those links withemotional component.

9th IPWSO Conference | 15

3.3 - The human centred development and initial evaluation of a task switching training video
game for children with PWS	  Nigel Robb1, Annalu Waller2 & Kate Anne Woodcock1	
  1. School of Psychology, Queen’s University Belfast;	
  2. School of Computing, University of Dundee	  	
  Background	  A deficit in task switching – one’s ability to respond flexibly to stimuli or events, depending on
external demands – has been associated with change-triggered temper outbursts in children with PWS.	
  Task switching can be improved via computerised practise but these improvements do not necessarily
extend to gains in daily life functioning (gains don’t always transfer). However, certain kinds ofcommercial video game include features that promote learning transfer and can mediate serendipitous
improvements in task switching.	
  We developed a prototype video game for training task switching in children with PWS. We evaluatedchanges in task switching ability mediated by engagement with the game in a placebo controlled crossover design.	
  Methods and results	  Seven children with PWS collaborated in the design of TASTER, a switching training game. This
collaboration ensured usability. Additionally, a systematic analysis of commercial video games thathave positive effects on task switching identified features which train switching and promote learningtransfer; these features were included in TASTER.	
  	
  Four children with PWS have completed the first stage of a placebo controlled cross-over evaluation,
involving engagement with either an experimental or placebo (no demands on switching) version of
TASTER. Children completed four neurocognitive tests of switching twice before training and again
after 1-3 hours of engagement with the game, spread over four weeks. Results to date indicate gains intask switching limited to the individual who has already engaged with the experimental version of thegame. Caregivers completed an informant report measure of task switching before and after training
but these data show small gains in switching across all children. The results of the cross-over phase andthose from further participants will be discussed.	
  Conclusions	  Human-centred design with children with PWS allowed a prototype switching training game to be
developed that establishes several conditions that are known to facilitate high learning transfer. Initial
results suggest that even short term engagement with the training can have a positive effect on task
switching ability.	
  Summary	  Temper outbursts due to changes to plans or routines have been linked with a reduced ability to switch
quickly between tasks in children with PWS. We have collaborated with a group of children with PWS
to design and develop a video game to train this ability, with the aim of reducing such outbursts. Initialevidence suggests that playing the game can improve task switching.	
  16 | 9th IPWSO Conference3.4 - Aberrant Behavior Checklist Scores in Children with Prader-Willi Syndrome compared tothose with Autism
Parisa Salehi, MD1, Amanda Lu, BA2, Anita E. Beck, MD, PhD3, Maida Chen, MD4, Soo-Jeong Kim,
MD5
1
Seattle Children’s Hospital, Division of Endocrine, University of Washington, Seattle, WA
2
Seattle Children’s Hospital, University of Washington, Seattle, WA
3
Seattle Children's Hospital, Division of Genetic Medicine, University of Washington, Seattle, WA
4
Seattle Children's Hospital, Division of Pulmonary and Sleep Medicine, University of Washington,
Seattle, WA5	
  Seattle Children's Hospital, Division of Psychiatry, University of Washington, Seattle, WA

Background: Children with Prader-Willi Syndrome (PWS) have behavioral difficulties that can be
impactful on families and caregivers. Various instruments have been utilized to evaluate behavior,including the Aberrant Behavior Checklist (ABC). This questionnaire is also used in children with
autism. Individuals with PWS can have behaviors similar to those with autism. In this study, we
compare ABC results in youth with PWS and those with autism.
Methods and Results: ABC scores from de-identified populations of youth with PWS from Seattle
Children’s Hospital (SCH) and University of Florida (UF) [n = 66 (44 females, 22 males), mean age
10.5 ± 6.6 years, age range 3-37 years] and children with autism (without PWS) from UF [n =102 (21females, 81 males), mean age 10.4 ± 3.5 years, age range 5-18 years]. The ABC was filled out by
parents or caregivers. Scores were calculated using standard methods and compared using two-tailed ttests. ABC scores were evaluated as total score and sub-scores (hyperactivity, irritability, lethargy,
speech, and stereotype). Scores are presented as mean±SD. The relationship between BMI z-score andABC scores in the SCH PWS population was evaluated using linear regression. IRB approval for
retrospective data review was obtained from SCH.
There was a significant difference in mean ABC total and sub-scores between the PWS (total
28.8±22.5, hyperactivity 8.1±7.6, irritability 10.4±8.6, lethargy 5.2±5.2, speech 2.7±2.5, stereotype
2.2±2.9,) and autism groups (total 61±29.5, hyperactivity 20.5±11.3, irritability 16±10.3, lethargy
13.5±9.2, speech 4.2±3.0, stereotype 6.8±5.0,) with p-values all <0.001.
There were no significant differences in ABC scores in the following PWS subgroups: deletion vs. nondeletion genetic subtype, male vs. female, age <13 vs. ≥13. In the PWS group from SCH (n = 24), there
was no significant relationship between BMI z-score and ABC scores.
Conclusion: ABC scores in youth with PWS are lower than those in autism despite overlap of
behavioral abnormalities and need of similar behavior, psychiatry, and education services. The results
may indicate fewer behavioral abnormalities in youth with PWS, or it may be an indication of theinadequacy of the ABC as a behavioral assessment in PWS. Also to be considered is the potential
influence of under reporting of abnormal behavior on score outcomes.
Summary: The ABC has been used to gauge abnormal behavior in different populations including
PWS and autism. Perhaps surprisingly, the results of our study show that children with PWS havelower ABC scores correlating with better reported behaviors than those with autism. There was nodifference in ABC scores among PWS children of different genetic subtypes, genders, or ages.

9th IPWSO Conference | 17

3.5 - Oxytocin vs. Placebo for the Treatment of Repetitive Behaviors, Disruptive Behaviors, andSocial Communication in Children and Adolescents with Prader-Willi Syndrome: Preliminary
Results
Bonnie P. Taylor, Ellen Doernberg, Anahid Kabasakalian, Casara Ferretti & Eric Hollander
Albert Einstein College of Medicine/Montefiore Medical Center (all authors)
Background. Oxytocin (OXT) has been implicated in the pathophysiology of Prader-Willi Syndrome(PWS). Studies have shown that the number and size of OXT neurons is significantly reduced inindividuals with PWS. Further, animal studies have demonstrated that a reduction in OXT neurons
leads to overeating, which reverses after OXT administration. OXT administration in individuals with
ASD impacts social communication skills, trust in others, and repetitive behaviors- all significant
issues for children with PWS. The few clinical trials of OXT in PWS have yielded some promising
results, including improvements in eye gaze and trust in others, and a reduction in anxiety. OXTs
effects on tantrums and appetite have been equivocal. To date, there have been no double-blind
placebo-controlled trails in children with PWS that examined the effects of OXT over the course of
more than 5 days.
Methods. We conducted an 8-week double-blind placebo-controlled treatment study of intranasal OXT(IN-OXT) in 24 children with PWS. Patients received an OXT dose of 16 IU per day (2 puffs per
nostril/4 IU each). The primary outcome measure was Eating Behaviors, including the Revised-Dykens
Hyperphagia Questionnaire, gut hormone measurements, dietary diary and BMI. Secondary andexploratory measures assessed repetitive behaviors (RBS-R and Y-BOCS), disruptive behaviors (ABCI), social communication (ABC-SW and SRS), quality of life (WHOQOL), hypotonia and oxytocinlevels (oxytocin receptor genotype and salivary oxytocin).
Results. An analysis of the sample that has completed the study by May 1st, 2016 will be presented.
The demographics of the sample will be described, including age, gender, and subtype (i.e., PWS bydeletion, UPD and imprinting). Analysis will be conducted examining end-study OXT-placebo
differences (controlled for baseline) for repetitive behaviors (RBS-R and Y-BOCS), disruptive
behaviors (ABC-I) and social communication (ABC-SW and SRS).
Conclusions. Based on the results, we will discuss the benefits of 8-weeks of intranasal oxytocin
administration versus placebo on repetitive behaviors, disruptive behaviors and social communicationin children 5-18 years old with PWS.
Summary. Oxytocin, a naturally occurring hormone in the body, may improve PWS-associatedbehaviors, including repetitive behaviors, disruptive behaviors and social communication. To examine
this, we conducted a pilot 8-week double-blind treatment study of intranasal OXT vs. placebo in 24
children with PWS. Results and conclusions will be briefly described.

18 | 9th IPWSO Conference3.6 - An overview of cognition in PWS
Joyce Whittington and Tony Holland
Department of Psychiatry, University of Cambridge, UK
Why study cognition?
(1) Scientific interest: How does the genetic defect in PWS lead to the cognitive phenotype?
(2) Education issues: Aspects of cognition that affect learning(3) Social/behavioural issues: How cognition affects observed behaviour and social interaction
Examples of contributions in each of these areas.
Drawbacks and limitations to research on cognition
As with many aspects of research in PWS, much of our view of cognition in PWS is based on oldreports, which in turn were based on small samples and included ‘clinically’ diagnosed participants.
Some of these reports contain findings which have never been replicated and which are perpetuated in
the literature by references to the original studies. Because of the difficulties inherent in research onrare conditions, not least because of the difficulties of obtaining reasonable sample sizes andrepresentative populations, replication is essential if we are to get a true picture. This is well illustrated
by the literature on cognition in PWS.
Rapid review of research on cognition
Findings are presented on general ability (IQ), attainment, language, comprehension, executivefunctions, and social cognition. The latter includes investigations of theory of mind, emotion
recognition, face processing and knowledge of social norms.

9th IPWSO Conference | 19

4.1 - Evaluation of the Effects of GH Therapy in Adult Patients with Prader-Willi Syndrome
GRUGNI Graziano, MD1, SARTORIO Alessandro, MD1, Danilo FINTINI, MD2, Antonino CRINO,
MD’2
1

Italian Auxological Institute, Piancavallo (Verbania), 2Bambino Gesù Children’s Hospital, Palidoro(Rome); ITALY.

Background: The clinical picture of Prader-Willi Syndrome (PWS) strongly supports the presence of
GHD. Apart from short stature, both PWS and GHD are characterized by body composition
abnormalities, impaired psychological abilities, altered physical strength, and reduced bone mineraldensity. GH treatment has been shown to normalize skeletal growth in PWS children and to haveadditional beneficial effects on body composition, muscular performances, and cognitive level. It hashitherto not been settled if treatment should be continued in PWS adults.	
   The objective of this study
was to analyze the effects of GH therapy in a group of PWS adults in comparison to what observed in
PWS patients without GH treatment.
Methods and results:	
   Forty-one subjects with PWS (21 females, aged 31.3+1.3 yr (mean+SE),
del15:UPD15= 31:10) were studied.	
   Twenty-one PWS were undergoing GH therapy from 7.5+0.7
years (Group A), while the other 20 patients were without GH treatment (Group B).	
  The examinationof PWS patients included: anthropometric measurements [Body Mass Index (BMI: (kg/m2), waist
circumference], body composition and bone mineralization (DXA), resting energy expenditure (indirectcalorimetry), glucose metabolism (OGTT-derived indexes), lipid profile, thyroid function, IGF-I level,
blood pressure, liver ultrasonography, cardiac assessment (M-mode, two-dimensional, and pulsed
Doppler echocardiographic studies), pulmonary function (spirometry). The comparison of the 2 study
groups showed the following results: BMI: 42.2+1.8 (A) vs 42.7+1.8 (B) (p=ns); Fat mass (%):
51.0+1.5 (A) vs 54.6+0.9 (B) (p<0.05); Lean body mass (kg): 49.0+2.2 (A) vs 40.8+1.4 (B) (p<0.003);	  Lean body mass (%): 49.0+1.5 (A) vs 45.4+0.9 (B) (p<0.05); Vertebral T-score: -1.46+0.30 (A) vs 1.47+0.20 (B) (p=ns); Femoral T-score: -1.31+0.24 (A) vs -0.59+0.20 (B) (p<0.03); Glycaemia mg/dl(basal): 89.2+5.4 (A) vs 111.8+10.6 (B) (p=0.06); Glycaemia mg/dl (120’ OGTT): 120.3+6.2 (A) vs147.3+9.6 (B) (p<0.03); Insulin (basal) (µU/ml): 13.0+1.8 (A) vs 12.3+1.4 (B) (p= ns); HbA1c (%):
5.5+0.09 (A) vs 6.2+0.29 (B) (p< 0.03); Total cholesterol (mg/dl): 181.9+9.4 (A) vs 208.2+9.1 (B)(p<0.05); IGF-I (µg/L): 179.1+10.1 (A) vs 102.7+9.6 (B) (p<0.0001); Moderate-severe NAFLD (%):
38.1% (A) vs 68.4% (B) (p<0.05); Vital capacity (L): 3.76+0.14 (A) vs 3.35+0.13 (B) (p<0.05); Forced
vital capacity (L) (%ref): 71.8+2.2 vs 59.6+4.2 (B) (p<0.02); Forced expiratory volume at 1.0 second(FEV1) (L) (%ref): 87.1+4.2 vs 68.5+4.3 (B) (p<0.005); Forced expiratory flow 25-75 (L/min) (%ref):80.4+3.4 vs 72.6+4.3 (B) (p<0.001).
Conclusions: Our results suggest that GH therapy may have a role in the strategic perspective of themore appropriate care to adult patients with PWS.
Summary:	
   Long-term GH therapy in adults with PWS is able to improve body composition, totalcholesterol levels, IGF-I levels, liver morphology, and pulmonary function, in the absence of negative
effects on carbohydrate metabolism and cardiac function.

20 | 9th IPWSO Conference4.2 - Hyperphagia: Cause or Consequence of Obesity?
Mark I. Friedman, Ph.D.
Nutrition Science Initiative
Early nutritional stages defined in Prader-Willi Syndrome (PWS) by Miller et al (2011) include
increased fat accumulation and body weight prior to the onset of hyperphagia. This observationsuggests that PWS is primarily a fuel partitioning disorder, in which hyperphagia is not a primary causeof the obesity.
Historically, both common obesity and that in PWS have been thought to be caused by a defect inenergy intake (hyperphagia) that results in increased fat accumulation and, eventually, obesity. In
contrast to this prevailing view, obesity has also been seen as a primary metabolic disorder of excessive
fat deposition, which triggers hyperphagia as a compensatory response to the “loss” of energy into
adipose tissue. This overeating in turn exacerbates fat gain. In addition to the example of PWS, otherfindings are consistent with this alternative perspective. For example, studies using animal models ofobesity also indicate that excessive lipogenesis and body fat accumulation occur before the onset of
hyperphagia and, in addition, that restricting energy intake to normal levels does not prevent theincrease in body fat mass.
The mechanism by which shifts in fuel partitioning towards fat storage stimulates eating behavior is not
yet established. In general terms, an increased flux of metabolic fuels into adipose tissue would reduce
the availability of energy-producing substrates much like limiting the supply of food through fasting
does. More specifically, animal studies suggest that a reduced capacity for hepatic fatty acid oxidationand its resultant effect on the generation of a hepatic metabolic “hunger” signal may be involved.
The propensity for fat accumulation is in part genetically determined and is usually expressed through asusceptibility to diet-induced obesity. This disposition to obesity is seen mostly clearly when the dietcontains a combination of large amounts of carbohydrates – particularly, refined grains and sugars –and fat. Such a diet would promote obesity by facilitating lipid synthesis and storage, while inhibiting
fatty acid mobilization and oxidation.
In keeping with the assumption that overeating causes obesity, treatment typically emphasizes caloric
restriction. This is true for all forms of obesity including that in PWS. But if hyperphagia is an attempt
to compensate for a loss of calories into body fat, then the persistent metabolic hunger driving
overeating can only be exacerbated by caloric restriction. From this perspective, treatment of obesity
should focus instead on modifying metabolism to shift fuel partitioning away from fat storage toward
pathways of oxidation. Drugs like Belanorib may work in this way. Alternatively, a low-carbohydrateor ketogenic diet could be effective in this regard because they would minimize fat synthesis andstorage and maximize the mobilization of stored fat and its oxidation. Thus, treating the obesity should
reduce or minimize hyperphagia and obviate the need to restrict calories.

9th IPWSO Conference | 21

4.3 - Efficacy and Safety of Diazoxide Choline Controlled-Release Tablet in Prader-Willi
syndrome: results of the Double-Blind Arm of the Study
Abhilasha Surampalli1, Marie Wencel1, June-Anne Gold1,2,3, Neil M. Cowen4 ,Virginia Kimonis1,3
1

Division of Genetics and Genomics, Department of Pediatrics, UC Irvine School of Medicine, Irvine, CA,
Loma Linda University School of Medicine, Loma Linda, CA,3 Children’s Hospital of Orange County, Orange,
CA, 4Essentialis, Inc., Carlsbad, CA

2

Background: Prader-Willi syndrome (PWS) is a complex, multisystem genetic disorder characterizedby multiple endocrine, neurological and behavioral abnormalities. To date, no medication has proveneffective in regulating appetite in PWS. It is conceivable that Diazoxide Choline Controlled-Release(DCCR) tablet can be used to control appetite and possibly improve on behavioral symptoms of PWS
patients, through the activation of a diverse set of downstream mediators. DCCR works by mimicking
sensitivity to leptin and insulin in AgRP and POMC neurons, reducing de-novo fatty acid biosynthesis,
stimulating β-oxidation of fat and normalizing GABA response, reducing hyperphagia, fat mass andaggressive behavior in PWS patients.
Methods and Results: Thirteen obese subjects with genetically confirmed diagnosis of PWS, between
10-22yrs were enrolled in the study PC025. Two subjects were withdrawn from the study due to a priorpsychiatric illness in one and progressively compromised glycemic control at the highest dose in theother. Eleven subjects completed the open-label treatment phase, were designated as Responders(hyperphagia response rate 92%) and randomized into the double-blind phase of the study. Data wasanalyzed for both open-label treatment phase and double-blind phase.
We found significant improvements in hyperphagia in DCCR treated subjects at the end of the openlabel treatment period (-31.6%, p=0.003) and in those who continued on DCCR in the double blindphase (-29.2%, p=0.006). There was significant reduction in ‘aggressive’, ‘threatening’ , ‘destructive’
behavior in comparison to all other PWS associated behaviors at the end of open label treatment phase(62.5% Vs 29.8% respectively, p=0.01). The effect of DCCR on behavior seems to be independent of
the effect on hyperphagia. Significant impacts were seen on fat mass (-3.8%, p=0.011), lean body mass(+5.4%, p=0.001), lean body mass/fat mass ratio (+9.8%, p=0.002) during open-label treatment. The
impacts on body composition were of similar magnitude in GH treated and GH naïve subjects. DCCR
treatment significantly reduced TG, Tot-C, and Non-HDL-C in both the open-label and double blindphase. The most common adverse events included peripheral edema which was responsive to dose
reduction and diuretics, hyperglycemia which responded to dose reduction and hirsuitism all of whichwere reversible.
Conclusion: DCCR significantly reduces hyperphagia; reduces fat mass while increasing lean bodymass, reduces aggressive, threatening and destructive behavior and significantly improved
cardiovascular risk factors.
Summary: Diazoxide is effective in reducing hyperphagia, body fat and behavior problems in PraderWilli syndrome. Side effects include fluid retention, hyperglycemia and hirsuitism.

22 | 9th IPWSO Conference4.4 - Oxytocin vs. Placebo for Hyperphagia, Eating Behaviors and Quality of Life in Children
and Adolescents with Prader-Willi Syndrome
Eric Hollander, Bonnie P. Taylor, Ellen Doernberg, Casara Ferretti & Anahid Kabasakalian
Albert Einstein College of Medicine/Montefiore Medical Center (all authors)
Background. Oxytocin (OXT) has been implicated in the pathophysiology of Prader-Willi Syndrome(PWS). Studies have shown that the number and size of OXT neurons is significantly reduced inindividuals with PWS. Further, animal studies have demonstrated that a reduction in OXT neurons
leads to overeating, which reverses after OXT administration. OXT administration in animal models
and human studies of obesity and type-2 diabetes have demonstrated an impact on eating behavior,weight, and insulin release and sensitivity. The few clinical trials of OXT in PWS have yielded somepromising results in eye gaze, trust in others, anxiety and hyperphagia, although differences in dosing
may have a differential effect on temper-tantrums due to cross-binding to vasopressin receptors. To
date, there have been no double-blind placebo-controlled trails in children with PWS that examined theeffects of OXT over the course of more than 5 days.
Methods. We conducted an 8-week double-blind placebo-controlled treatment study of intranasal OXT(IN-OXT) in 24 children with PWS. Patients received an OXT dose of 16 IU per day (2 puffs per
nostril/4 IU each). The primary outcome measure was Eating Behaviors, including the Revised-Dykens
Hyperphagia Questionnaire, gut hormone measurements, dietary diary and BMI. Secondary andexploratory measures included quality of life (WHOQOL), hypotonia and salivary oxytocin levels.
Results. An analysis of the sample that has completed the study by May 1st, 2016 will be presented.
The demographics of the sample will be described, including age, gender, and subtype (i.e., PWS bydeletion, UPD and imprinting). Analysis will be conducted examining end-study OXT-placebo
differences (controlled for baseline) for Eating Behaviors (Revised-Dykens Hyperphagia
Questionnaire, gut hormone measurements, dietary diary and BMI) and quality of life (WHOQOL).
Adverse event data will be presented.
Conclusions. Based on the results, we will discuss the benefits of 8-weeks of intranasal oxytocin
administration versus placebo on eating/food-seeking behaviors and quality of life in children 5-18
years old with PWS.
Summary. Oxytocin, a naturally occurring hormone in the body, may improve PWS-associatedbehaviors, including hyperphagia, and eating behaviors, body composition, BMI, weight, gut hormone
measures and quality of life. To examine this, we conducted a pilot 8-week double-blind treatment
study of intranasal OXT vs. placebo in 24 children with PWS. Results and conclusions will be briefly
described.

9th IPWSO Conference | 23

4.5 - Laparoscopic Sleeve Gastrectomy in Children and Adolescents with Prader-Willi
Syndrome: A Matched Control Study
Aayed R. Alqahtani1, MD, RCSCS, FACS; Mohamed O. Elahmedi1, MBBS; Awadh R. Al Qahtani2,
MD, MSc, FRCSC; Jaehoon Lee3, PhD; Merlin G. Butler4, MD, PhD, FFACMG
1

Obesity Chair, Department of Surgery, College of Medicine, King Saud University, Riyadh, Saudi
Arabia; 2Department of Surgery, College of Medicine, King Saud University, Riyadh, Saudi Arabia.
3
College of Education, Texas Tech University, Lubbock, Texas, USA; 4Departments of Psychiatry &Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City, Kansas, USA.
Background: Obesity is a leading mortality and morbidity cause in Prader-Willi syndrome (PWS). Ourcenter, which developed a standardized care pathway for pediatric bariatric surgery, runs a prospective
clinical outcome study on children and adolescents undergoing weight loss surgery. This study aimed
to assess weight loss and growth after sleeve gastrectomy (LSG) in pediatric patients with PWS
compared to those without the syndrome.
Method: Clinical data of all PWS patients who underwent LSG were abstracted from our prospective
database that included all pediatric patients who underwent bariatric surgery. These data were thencompared to a 1:3 matched non-PWS for age, gender and BMI. Data for up to 5 years follow-up wereanalyzed.
Results: The twenty-four PWS patients (mean age=10.7; 6 < 8 years old, range 4.9 to 18) had apreoperative body mass index (BMI) of 46.2 ± 12.2 kg/m2. All PWS patients had obstructive sleep
apnea (OSA), 62% had dyslipidemia, 43% had hypertension, and 29% had diabetes mellitus. BMIchange at the first, second, third, fourth and fifth annual visits was -14.7 (n=22 patients), -15.0 (n=18),-12.2 (n=13), -12.7 (n=11), and -10.7 (n=7), respectively in the PWS group, while the non-PWS group
had a BMI change of -15.9 (n=23), -19.1 (n=17), -17.4 (n=15), -18.9 (n=9), and -17.9 (n=8),
respectively. No significant difference was observed in postoperative BMI change (p-value 0.2 to 0.7)
or growth (postoperative height z-score p-value at each annual visit: 0.07-0.9). 95% of comorbidities inboth groups were in remission or improved, with no significant difference in the rate of comorbidity
resolution after surgery (p-value 0.72). One patient was readmitted 5 years after surgery withrecurrence of OSA and heart failure. No other readmissions occurred, and there were no reoperations,
postoperative leak, or other complications. No mortality or major morbidity was observed during thefive years of follow-up. Among the PWS patients who reached their follow-up visit timepoints, thetotal follow-up rate was 94.1%, while in the non-PWS group it was 96%. All patients who missed afollow-up visit were subsequently seen in future follow-ups, and no patient was lost to follow-up ineither group.
Conclusions: PWS children and adolescents underwent effective weight loss and resolution ofcomorbidities after LSG, without mortality, significant morbidity, or slowing of growth. LSG should beoffered to obese PWS patients with heightened mortality particularly as no other effective alternative
therapy is available.
Summary
Prader-Willi syndrome leads to severe obesity and significant comorbidities. To date, there is noeffective treatment for the severe obesity associated with this syndrome. In this study, Laparoscopic
sleeve gastrectomy is a solution that safely provides significant resolution of obesity and associatedcomorbidities, with no major complications.

24 | 9th IPWSO Conference4.6 - Long-Term Outcome After Biliopancreatic Diversion in Prader-Willi Syndrome
Antonino Crinò, Danilo Fintini, Sarah Bocchini, Francesco De Peppo1, Romina Caccamo1, Graziano
Grugni2
Autoimmune Endocrine Diseases Unit, Surgery Unit1, Bambino Gesù Hospital, Research Institute, Palidoro(Rome), Italian Auxological Institute, Piancavallo (Verbania)2 - ITALY

Background: Improvement in weight control remains the most important goal of any treatment programin Prader-Willi syndrome (PWS). Dietary restriction, physical activity and anorexic drugs, together
with behaviour interventions, are generally ineffective to induce a long-term weight loss. Thanks toadvances of our understanding of safety and efficacy of bariatric procedures in adults with simple
obesity, interest in bariatric surgery has increased also for PWS patients. To date, bariatric surgery
experience in PWS is limited, and different procedures have been used with varying success.
Malabsorptive procedures such as biliopancreatic diversion (BPD) are not always recommended forPWS due to lack of safety data and concerns about long-term nutritional complications. Moreover, data
regarding the long-term outcome of this procedure in PWS are still lacking.
Patients and methods: We report 7 patients (4 males) with genetically confirmed PWS (5 del15, 2
UPD), who underwent Scopinaro biliopancreatic diversion after an inability to control food intake withthe classical approaches and with a progressive and excessive weight gain. The age of surgery was
17,6±1,6 yrs (range: 15,5-20) and the BMI (kg/m2) was >40 in all cases except one (47,5±8.5). At
baseline, severe co-morbidities were present, such as obstructive sleep apnea (OSAS), type 2 diabetes
mellitus (T2DM), metabolic syndrome and/or steatohepatitis.
Results: No perioperative complications were observed. After a follow-up period of 15.5±6.8 yrs(range 8,4-25,8, mean age at follow-up 33.1±6.2 yrs) the maximum weight loss (MWL) was 34.4±20,3kg (7-61). Following BPD, BMI decreased in 3 patients, was stable in 2 subjects and significantly
increased in 2 individuals after 8,4 and 25,8 yrs, but in these cases MWL was low (10 and 7 kg,
respectively). The mean BMI at follow-up was: 42.4±8.7 (29,5-51,6).
After BPD, appetite was reduced in 3 cases; 5 subjects had hypocromic anemia and diarrhea; OSAS
were present in 4 pts and osteoporosis/osteopenia in all study group. T2DM improved significantly.
One patient suddenly died at the age of 37.3. After surgery all patients received iron, calcium, vitaminD, minerals and multivitamin preparations to prevent nutritional deficiency.
Conclusion: Bariatric surgery should be considered in PWS patients as a realistic control of morbid
obesity, when other classical approaches have failed. The outcome of BPD is variable in PWS. It could
be a good option in the presence of serious comorbility and in selected and well-disciplined PWS
patients, with co-operating families. However, a careful long-term multidisciplinary follow-up isalways necessary.
Summary: Long-term outcome with BPD in PWS are variably satisfactory and are associated withimprovement of metabolic abnormalities and important weight loss. However, reduced bone mineraldensity and diarrhea are frequently reported. In this light, a careful long-term multidisciplinary followup is mandatory.
	  9th IPWSO Conference | 25

4.7 - Histamine H3 Receptor Antagonist on Sleep Disturbances
Holger Stark
Heinrich Heine University Düsseldorf, Institute of Pharmaceutical and Medicinal Chemistry,
Universitaetsstr. 1, 40225 Duesseldorf, Germany.
Histamine is an important neurotransmitter in the peripheral and central nervous system. It is mainly
acting via four different membrane bound G-protein coupled receptors. Antagonists for the histamine
H1 and H2 receptor subtypes are or have been known blockbuster drugs for the treatment of allergy
and ulcer, respectively. The histamine H3 receptor is the main modulator of this transmission. It can act
as an auto- as well as heteroreceptor and thereby influencing numerous other neurotransmitter
innervation. Among others, this modulation is changing the orexinergic, dopaminergic, serotoninergic
and acetyl cholinergic pathways. Although many histamine H3 receptor antagonists are in the
preclinical phase, some have already reached clinical trials. Due to the numerous interaction and crossreactions the antagonists have been tested for diverse therapeutic indications from ADHS,
schizophrenia, obesity, cognitive impairment, epilepsy and neuropathic pain. The most prominent
outcome has been achieved on sleep disorders as a strong wake-enhancing agent. Recently thehistamine H3 receptor antagonist pitolisant (Wakix®) has been approved by the European Medicine
Agency (EMA) as orphan drug on the treatment of narcolepsy. In addition to this, it is in actual latephase clinical trials on daytime sleepiness with Parkinson patients.
Summary. The sum of the different effects and side effect observations in preclinical and clinicalstudies may suggest the symptomatic use of histamine H3 receptor antagonists on patients with PraderWilli syndrome after further clinical trials. At this stage the therapeutic potential is highly speculative,
but with the given data on the early clinical data a reduction in disease burden may be achieved.

26 | 9th IPWSO Conference4.8 - AZP-531, an Unacylated Ghrelin Analog, Improves Food-related Behavior in Patients with
Prader-Willi Syndrome: A Multicenter, Randomized, Placebo-controlled Study
Soraya Allas1, Assumpta Caixàs2, Christine Poitou3, Muriel Coupaye3, Denise Thuilleaux4, Françoise
Lorenzini5, Gwenaelle Diene6, Antonino Crinò7, Frédéric Illouz8, Graziano Grugni9, Thomas Delale1,
Thierry Abribat1, Maithé Tauber6
1

Alizé Pharma, Ecully, FR, 2 Endocrinology and Nutrition Department, Sabadell University Hospital, Corporació
Sanitària Parc Taulí, Research Institute I3PT, Sabadell (Barcelona), SP, 3 Nutrition Department, Institute ofCardiometabolism and Nutrition, Assistance Publique-Hôpitaux de Paris, Pitié-Salpêtrière Hospital, FR, 4
Department of Rare Diseases, Marin Hospital, Hendaye, FR, Rangueil Hospital, Toulouse, FR, 6 Department ofEndocrinology, Bone Diseases, Genetics, and Gynaecology, Children's Hospital, Toulouse, FR, 7	
  Autoimmune
Endocrine Diseases Unit, Bambino Gesù, Research Hospital, Palidoro (Rome), IT, 8 Department ofEndocrinology, Diabetes and Nutrition, Angers’ Hospital, Angers, FR, 9 Division of Auxology, Istituto
Auxologico Italiano Piancavallo, Verbania, IT

Background: Plasma levels of Acylated Ghrelin (AG), the most potent orexigenic hormone, areelevated in Prader-Willi syndrome (PWS) and are hypothesized to contribute to the pathophysiology ofhyperphagia. Administration of unacylated ghrelin and AZP-531, a first-in-class peptide analog, havebeen shown to prevents AG-induced food consumption in animals, and improves glucose control anddecreases weight in animal models and in Phase 1 clinical trials.
Methods and Results: In a multicenter, randomized, placebo-controlled, parallel group study, weinvestigated the safety, tolerability, and efficacy on food-related behavior of AZP-531 over a 2-weektreatment period in 23 male and 24 female patients with genetically confirmed PWS and evidence ofhyperphagia (mean age: 26.8 ± 6.7 yrs, range: [13-46 yrs], mean BMI: 38.00 ± 12.01 kg/m2, range:[20.6-67.4 kg/m2]). Participants were randomly assigned to receive subcutaneous AZP-531 (3 mg or 4mg) or placebo once daily. Adverse events were monitored throughout the treatment period and up to
Day 28. Study assessments were performed on Day -1 (baseline), Day 1 (after the first injection) andDay 14. AZP-531 was well tolerated with no serious or severe adverse events and no clinicallysignificant changes with respect to safety laboratory tests. A significant improvement in food-related
behavior, as assessed by the Hyperphagia questionnaire, was noted in AZP-531-treated patients on Day
14 (P<0.05 vs placebo) with particular improvement in the severity score (P<0.05 vs placebo). Findings
were supported by reduction in appetite feelings following breakfast on Day 14, as assessed by a newly
developed patient-reported outcome scale. No change was observed in body weight which is not
unexpected following a short-term treatment in this study population with highly variable weight and
BMI at baseline. However, a significant reduction of waist circumference was noted in the AZP-531
group (P<0.05 vs baseline) and not in placebo (NS vs baseline). In addition, AZP-531 tended to
improve glucose control and this improvement was greater in patients with higher fasting or postprandial glucose levels at baseline.
Conclusions: Daily AZP-531 for 2 weeks was well tolerated in patients with PWS, corroborating
findings from previous human studies. Data suggest that AZP-531 may be a beneficial treatment
strategy in this patient population with elevated ghrelin levels and support further investigation inlarger controlled trials to assess long-term safety and efficacy on food-related behavior and metabolic
parameters.
Summary: Blood levels of Acylated Ghrelin (AG), the appetite hormone, are elevated in patients with
PWS and are hypothesized to contribute to hyperphagia. Unacylated Ghrelin (UAG) is known toantagonize some effects of AG. In this study performed in 47 patients with PWS, we demonstrated thatadministration of AZP-531, a fragment of UAG that works similarly as UAG, was well-tolerated andimproved food-related behavior.
9th IPWSO Conference | 27

4.9 - Weight loss and Improvement in Hyperphagia-Related Behavior: Results from best PWS, a
Phase 3, Randomized, Placebo-Controlled Clinical Trial of Beloranib in Patients with PraderWilli Syndrome
Shawn E. McCandless1, Elizabeth Roof2, Elizabeth M Dykens2, Jaret Malloy3, Dongliang Zhuang3,
Dennis Kim3, Merlin G. Butler4
1

UH Case Medical Center and Case Western Reserve University, Cleveland, OH, 2 Vanderbilt University,
Nashville, TN, 3 Zafgen, Inc., Boston, MA, 4 University of Kansas Medical Center, Kansas City, KS

Background: Prader-Willi syndrome (PWS) is the leading genetic cause of life-threatening obesity.
PWS is associated with reduced life expectancy; insatiable hunger characteristic of PWS can cause
gastric necrosis and choking while obesity and other metabolic derangements increase the risk ofmetabolic disease and cardiorespiratory events. Beloranib inhibits MetAp2, an enzyme that influences
metabolism, lipid synthesis, and fat storage, and was recently shown to reduce body weight andhyperphagia in a study of 17 patients with PWS.
Methods and Results: This 26-week clinical trial investigated biweekly beloranib injection in patientswith PWS aged 12-65 years. Co-primary efficacy endpoints were change in body weight andhyperphagia-related behavior (measured by Hyperphagia Questionnaire for Clinical Trials [HQ-CT]).
The randomized portion of the study was concluded early due to venous thromboembolic events inbeloranib clinical trials. The intent-to-treat population included 107 patients: 74 completed the study,
27 stopped early due to halting of the study (these completed >75% of the study), 6 withdrew due toadverse events (AEs). Baseline characteristics: 52% Male, mean±SD age 20±6y, 101.4±26.3kg, BMI
40.0±10.1kg/m2, HQ-CT total score 16.9±6.6 (range 0-36). After 26 weeks, the LS mean±SE weightchange from baseline for placebo was 4.2±0.9% (N=34) vs -4.1±0.9% with 1.8 mg beloranib (LS meandifference -8.2%, 95% CI, -10.8 to -5.6, p<0.0001, N=36) and -5.3±0.9% with 2.4 mg beloranib(-9.5%, -12.1 to -6.8, p<0.0001, N=37). The LS mean±SE change in HQ-CT total score (reduction
indicates improvement) with placebo was -0.4±1.2 vs -6.7±1.1 with 1.8 mg beloranib (LS meandifference -6.3, 95% CI, -9.6 to -3.0, p=0.0003) and -7.4±1.3 with 2.4 mg beloranib (-7.0, -10.5 to -3.6,
p=0.0001). Most common AEs were injection site bruising, aggression, and hyperphagia; only injection
site bruising was more frequent with beloranib vs placebo. Psychiatric disorder AEs occurred at ahigher rate with beloranib, were primarily mild to moderate in severity and generally resolved (baseline
incidence of psychiatric disorders: 66%, consistent with the patient population). The incidence ofserious AEs was low and similar across treatment groups (2.7-5.9%). Six beloranib-treated patients
withdrew due to AEs during the randomized treatment period (4 psychiatric AEs, 1 injection site pain,
1 pulmonary embolism resulting in death). Investigation of the pulmonary embolism leading to death isongoing.
Conclusions: This is the first Phase 3 clinical trial to show statistically and clinically significant
weight loss and improvement in hyperphagia-related behavior in patients with PWS.
Summary: This study investigated the effect of beloranib on body weight and hyperphagia in patientswith PWS. Beloranib produced weight loss and improvements in hyperphagia-related behavior
compared to placebo. AEs were generally consistent with the patient population and prior clinical trials.

28 | 9th IPWSO Conference5.1 - Loss of Magel2 Impairs the Development of Hypothalamic Anorexigenic Circuits
Julien Maillard1,2, Sophie Croizier1, Charlotte Vanacker2, Joshua Cook1, Vincent Prevot2,
Maithe Tauber3, Sebastien G. Bouret1,2
1

The Saban Research Institute, Developmental Neuroscience Program, Children’s Hospital Los Angeles,
University of Southern California, Los Angeles, CA 90027, USA, 2 Inserm, Jean-Pierre Aubert Research Center,
U1172, University Lille 2, Lille, 59045, France, 3 Department of Endocrinology, Bone Diseases, Genetics, andGynecology, Centre de Référence du Syndrome de Prader-Willi, Children's Hospital, Toulouse, France.

Background. Prader-Willi syndrome (PWS) is a genetic disorder characterized by a variety ofphysiological and behavioral dysregulations, including hyperphagia, a condition that can lead to lifethreatening obesity. Feeding behavior and body weight regulation are highly complex and dynamic
processes with multiple feedback loops that involve both peripheral and central systems. The arcuate
nucleus of the hypothalamus (ARH) is a nucleus of the brain that is critical for the regulation of
homeostatic processes such as feeding, and this nucleus develops during neonatal life under of theinfluence of both environmental and genetic factors. Although much attention has focused on themetabolic and behavioral outcomes of PWS, an understanding of its effects on the development ofhypothalamic appetite-related neural circuits remains elusive.
Methods and Results. We found that mice lacking Magel2, one of the genes responsible for the
etiology of PWS, display an abnormal development of axonal projections from the ARH. Notably, thedensity of anorexigenic α-melanocyte-stimulating hormone immunoreactive axons was reduced in
adult Magel2-null mice, while the density of orexigenic agouti-related peptide fibers in the mutant miceappeared identical to that in control mice. Based on previous findings showing the pivotal role ofneonatal leptin and ghrelin in hypothalamic development, we also measured leptin and ghrelin levels in
Magel2-null and control neonate mice and found that mutant mice have normal leptin and ghrelinlevels.
Conclusion. Together, these findings suggest that a loss of Magel2 leads to the disruption of
hypothalamic feeding circuits, an effect that appears to be independent of the neurodevelopmental
effects of leptin and ghrelin.
Summary. This work indicates that the development of neurons that cause satiety is attenuated in amouse model for PWS. These findings might help understanding the insatiable appetite associated withPWS.

9th IPWSO Conference | 29

5.2 - Appetite suppression by allosterically enhancing dopamine-2 receptor (D2R) signaling in
Snord116 deletion mouse model for Prader-Willi syndrome.
Cristina Grande1, Andras Kern1, Hua Lin2, Theodore Kamenecka 2, Roy G Smith1
1

Department of Metabolism and Aging, 2 Department of Molecular Therapeutics
The Scripps Research Institute, Jupiter, FL (USA)
Background. Prader-Willi Syndrome (PWS) is a complex genetic disorder in which cognitive
disabilities, hyperphagia and early childhood obesity are major hallmarks. PWS patients have a delayed
activation of brain areas involved in satiety, and hyperactivation of neural circuitry involving
motivation, reward, taste and food-seeking behavior. Dopamine is a neurotransmitter that regulates
feeding behavior, cognitive function, motivation and reward. We had previously demonstrated
formation of heteromers between the ghrelin receptor (GHSR1a) and the dopamine-2 receptor (D2R)
on hypothalamic neurons is necessary for dopamine suppression of food intake. PWS is associated withhyperghrelinemia that effectively reduces the concentration of GHSR1a on these neurons. We
hypothesize that allosterically enhancing interactions between GHSR1a and D2R in GHSR1a:D2R
heteromers will reduce appetite in patients with PWS.
Methods and Results. To test our hypothesis two different classes of GHSR1a antagonists (JMV2959
and YIL781) were injected alone or in combination with a D2R selective agonist (cabergoline), into theSnord116+/- mouse model for PWS. Snord116+/- male mice (Het) and littermate controls (WT) were
single housed, fasted for 16 hours and injected with either vehicle, GHSR antagonist (JMV or YIL),
cabergoline or the combination of the two and then provided food. Food intake was monitored for 24hours. Cabergoline significantly suppressed food intake, but was blocked by JMV. By contrast, YIL
inhibited food intake and enhanced the anorexigenic effect of the D2R agonist; however the effects of
YIL were short-lived. We therefore synthesized a library of new GHSR1a antagonists and screened
them in HEK293 cell line, co-expressing GHSR1a and D2R for their effects on Ca2+ mobilization. All
the compounds inhibited ghrelin-induced Ca++ release, and subsets either inhibited (Type A) or
enhanced (Type B) dopamine-induced Ca++ mobilization. The most potent Type A and B antagonists
were tested for inhibition of food intake in Snord116+/- mice in the presence or absence of cabergoline.
Type B antagonists enhanced the anorexigenic effect of cabergoline.
Conclusions. We have identified a new class of GHSR1a antagonists that block ghrelin signaling, butenhance D2R agonist-induced reduction in food consumption in the Snord116+/- mouse model of PWS.
Summary. Allosteric modulation of GHSR1a:D2R signaling has the potential to inhibit hyperphagia
associated with PWS, providing new opportunities to design pharmacologic agents for therapeuticintervention.	
  30 | 9th IPWSO Conference5.3 - Sleep phenotype of Prader-Willi Syndrome is partially recapitulated in MAGEL2 null mice
Carrie E. Mahoney, PhD and Thomas E. Scammell, MD
Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115
Background. Daytime sleepiness, disrupted sleep, and cataplexy-like falling episodes are common in
Prader-Willi Syndrome (PWS), but the cause of these symptoms is unknown.
Methods and Results. Using EEG, EMG, and video recordings, we have examined sleep/wakebehavior in MAGEL2 null mice, a model of PWS. These mice have normal total amounts of wake (W),
Non-REM sleep (NR), and REM sleep (R) when housed on a 12:12 light:dark cycle. However,compared to their wild type littermates (WT), MAGEL2 null mice have shorter NR bouts during thedark and light phases. Additionally, MAGEL2 null mice have more bouts of W and NR during thedark and light phase. MAGEL2 null mice did not have any cataplexy, even with stimuli that should
elicit positive emotions.
Conclusion. These short bouts and frequent state transitions indicate that MAGEL2 null mice lack theability to maintain sleep for long periods.
Summary. These findings in MAGEL2 null mice are similar to the sleepiness and disrupted sleep
common in PWS. Future research targeting orexin and oxytocin signaling, which are known to bealtered with MAGEL2 deletion, should provide helpful insights into the nighttime awakenings anddaytime sleepiness experienced by many people with PWS.
Support: Foundation for Prader-Willi Research	  9th IPWSO Conference | 31

5.4 - Fluoxetine is an effective treatment to reduce respiratory distress in Necdin deficient mice
Valery Matarazzo1, Yuri Shvarev2, Fabienne Schaller1, Laura Caccialupi1, Nazim Kourdougli1, Evan
Deneris3, Hugo Lagercrantz2, Patricia Gaspar4, Laurent Bezin5, Pascale Durbec6, Gérard Hilaire1,
Françoise Muscatelli1
1

INMED INSERM U901, Aix-Marseille Université, Marseille, France, 2Karolinska Institute,
Stockholm, Sweden, 3Case Western Reserve University, Cleveland, USA, 4IFM, INSERM U839 ,UPMC, Paris, France, 5CRNL INSERM U1028 - CNRS UMR5292 – UCB Lyon1, Lyon, France,
6
IBDM, CNRS UMR7288, Marseille, France
Background
Prader-Willi syndrome (PW) is a rare neurodevelopmental disorder caused by the genetic loss ofpaternal expression of several maternally imprinted genes on chromosome 15q11–13, among which
NECDIN. The symptoms include a various range of sensori-motor, endocrine, cognitive andbehavioural disturbances, including breathing deficits starting at birth such as apnea and blunted
respiratory responses to hypercapnia. In mice, loss of Necdin recapitulates these breathing deficits
found in PW patients and it is associated with brain serotonin homeostasis abnormality suggesting the
involvement of a serotonopathy in such respiratory symptoms. However, the mechanism at the basis of
this pathophysiology is unknown.
Methods and Results
We have investigated the expression of Necdin in the 5HT neurons and observed that Necdin isexpressed at the beginning of the serotoninergic lineage. During embryonic development, lack of
Necdin leads to defects in migration of 5-HT neurons, to an altered 5-HT neuroarchitecture, and to aloss of 5-HT neurons. Necdin KO mice present serotoninergic dystrophic neurons with enlarged
varicosities associated and with increase in spontaneous firing. At the molecular level, we found anincrease of 5-HT reuptake activity and an increase expression of the 5-HT transporter. Considering
these last results, we assessed in vivo the efficiency of fluoxetine, an inhibitor of 5-HT reuptake, torescue the respiratory deficits. We demonstrated that during the neonatal period, fluoxetine
administration can restore the respiratory response to hypercapnia and reduce the number of apnea.
Conclusions
On the whole, we show that lack of Necdin has pleotropic effects on the serotoninergic system.
However a fluoxetine treatment, allowing an increase of extracellular 5HT, appears sufficient to restore
normal breathing in Necdin deficient mice.
Summary
The Necdin mutant mouse recapitulates the respiratory deficits found in PW patient and thus permitted
us to investigate the pathophysiology of this symptom. We found that the homeostasis of brain
serotonin, a modulator of breathing activity, is dysregulated and that treatment of mutant newborn micewith fluoxetine can reduce respiratory apnea.

32 | 9th IPWSO Conference5.5 - Fatty Acyl Amides as Novel Therapeutics for the Treatment of Osteoporosis in PWS
Saja Baraghithy1, Ibrahim Knani1, Rivka Hadar1, Reem Smoum2, Raphael Mechoulam2, Rachel
Wevrick3, Itai Bab4, Joseph Tam1
Obesity and Metabolism Laboratory, 2Medicinal Chemistry Laboratory, The Institute for Drug
Research, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem
91120, Israel; 3Department of Medical Genetics, University of Alberta, Edmonton, AB Canada, T6G
2E1; 4Bone Laboratory, Faculty of Dental Medicine, The Hebrew University of Jerusalem, Jerusalem
91120, Israel.
1

Background: Decreased bone mineral density (BMD), increased fracture risk	
   secondary toosteoporosis, and short stature are common features of individuals with Prader-Willi syndrome (PWS),
affecting 60% to 90% of the patients. Recently, we described the presence of an endogenous long-chain
fatty acyle amide, N-oleoyl serine (OS), in bone, and demonstrated its critical involvement in theregulation of bone remodeling and osteoporosis in mice.
Methods and Results: Here, we characterized the skeletal phenotype of an established mouse modelfor PWS, Magel2-null mice, and tested the skeletal effects of a newly synthesized OS derivative,
named oleoyl α-methyl serine (KAL671), in this model.
In comparison with wild-type control animals, female Magel2-null mice showed a low bone mass
phenotype, resulting from a combined reductions in trabecular number, connectivity density andcortical thickness. In vitro, KAL671 enhanced the number of osteoblasts, the bone forming cells, andinhibited bone resorption and osteoclastogenesis. In vivo, chronic treatment with KAL671 (0.5 mg/kg
for 6 weeks), completely prevented the trabecular bone loss observed in vehicle-treated Magel2-nullmice. The KAL671-stimulated increase in trabecular bone formation occurred mainly due to increased
trabecular number and thickness. Moreover, KAL671 treatment completely rescued the reduction in thefemoral cortical thickness.
Conclusions: Our data identify the importance of Magel2 gene in the regulation of bone remodelingand mass in PWS, and describe the skeletal efficacy of a novel fatty acyl amide for the treatment of
osteoporosis-like features in Magel2-null mice. Moreover, the present study provides a preclinicalproof for further clinical development of KAL671, as a bone anabolic and anti-resorptive agent, for thetreatment of osteoporosis in PWS.
Summary: Using an established mouse model for PWS, cell culture experiments and a novel
pharmacological tool, this project significantly contributes to the understanding of one of the major
pathological processes associated with PWS, osteoporosis, and may enhance the translation of ourbasic scientific findings to the development of therapeutic interventions for PWS.
	  9th IPWSO Conference | 33

5.6 - Genomic imprinting: a new epigenetic regulation of sleep
Celina Garcia-Garcia, Edoardo Balzani, Ilaria Cosentini and Valter Tucci
Neuroscience and Brain Technologies Department, Istituto Italiano di Tecnologia
Background. Sleep-wake and food-intake disturbances are often reported in Prader-Willi Syndrome(PWS). PWS is a rare neurodevelopmental disorder that is caused by genomic imprinting defects
within the small nuclear ribonucleoprotein N (SNPRN) cluster of the human chromosome region
15q11-13. The small nucleolar RNA 116 (SNORD116, also called HBII-85) gene, a non-coding
molecule that participates in the modifications of other small nuclear RNAs has been identified as oneof the key players for this syndrome.
Methods. To investigate the link between imprinting defects, sleep and food-intake behaviors in PWS,
we studied the mouse mutant model PWScrm+/p-, which lacks Snord116 in the orthologous locus on
chromosome 7C. The chromosomal region that is involved in the pathogenesis of PWS comprises anumber of imprinted genes that present complex parent-of-origin expression. Some genes are
preferentially expressed from the paternal allele while others from the maternal allele. The
monoallelically expression of many imprinted genes is tissue-dependent and has been confirmed only
in development, neglecting the imprinting status in adulthood. The deleted allele carried by our mutants
is placed within the critical region of PWS in which paternally expressed small nucleolar RNAs
(snoRNAs) resides. We focused our attention on mice carrying the paternally inherited deletion, sincematernally inheritance is phenotypically similar to wild-types.
Results. We observed specific electrophysiological deficits during sleep, which suggest that paternallyexpressed Snord116 is involved in the 24-h regulation of sleep-wake cycles. Moreover, we reported
important changes in timing behaviors across timescales. In particular, PWScrm+/p- mutants show delays
in seconds-to-minutes (interval timing) cognitive processes and in food anticipatory activity (FAA)
compared to wild-type littermate controls.
Conclusions. In this study we discovered a novel role of the Snord116 imprinted gene in sleep andworking-for-food timing behaviors. We report, for the first time, that imprinting of Snord116 occurs inmouse brain structures that are important for sleep and timing behaviors.
Summary. We annotate specific sleep and behavioural/cognitive abnormalities as direct and/or indirectendophenotypes of Snord116 and Ipw A-C deletion within the Prader-Willi genomic region. This reportadds translational validity of the PWScrm+/p- murine model to the investigation of PWS.

34 | 9th IPWSO Conference6.1 - The Global Prader-Willi Syndrome Registry
Jessica Bohonowych1,2 Jennifer Miller3, Shawn McCandless4, and Theresa Strong1,21

Global PWS Registry, 2Foundation for Prader-Willi Research, Walnut, CA; 3Department of Pediatrics,
University of Florida, Gainesville, FL; 4 Department of Genetics and Genome Sciences, Case Western
Reserve University, Cleveland, OH.
Background: The Global Prader-Willi Syndrome Registry was developed to support and accelerate
PWS research and clinical care. The Registry has an Institutional Review Board (IRB)-approved
protocol and consent/assent process, and aims to: document the full range of the PWS phenotype tobetter understand the natural history of the disorder; enable data trend analysis to generate new insights
into PWS and identify areas for additional study; facilitate partnerships with academic researchers andpharmaceutical companies; guide the development of standards of care; expedite the completion of
PWS clinical trials; and allow participants to store their PWS medical data in one place. The Registry is
managed and funded by the Foundation for Prader-Willi Research (FPWR), is hosted by the National
Organization of Rare Disorders (NORD), and is a participant in the NIH-supported Global Rare
Disease Registry.
Methods and Results: The Global PWS Registry launched in May 2015 and has ~800 participants as ofearly 2016. It is comprised of a series of 37 web-based surveys covering medical history,
developmental history, behavior, mental health, medications and quality of life. The platform is flexible
and allows the capture of longitudinal data and addition of new surveys as needed. Data is self-reported
by a parent or guardian of individuals with PWS, with future plans for a clinical portal that will link
physician entered to participant reported data through a global unique identifier (GUI). The initial
marketing and enrollment push has been through social media, newsletters, and e-mails from theFoundation for Prader-Willi Research (FPWR) and the Prader-Willi Syndrome Association(PWSA(USA)). A number of help resources have been created to guide families through theregistration and informed consent process. These include a “getting started video”, a “getting started
PDF”, a private Facebook group, webinars, brochures, FAQ documents, and presentations at family
conferences. The second phase includes working with group homes, PWS clinics, physicians, and PWS
groups globally. There are plans for the registry to be available in multiple languages.
Conclusions:
The Global PWS Registry successfully launched in 2015. With growing participation, the registry is
poised to begin leveraging de-identified data through collaborations with researchers, industry, andother partners to advance the understanding and treatment of PWS.
Summary:
The Global PWS Registry is a web-based natural history study. The Registry launched in 2015 and thecoming year includes plans to continue enrollment, promote survey completion, and begin leveraging
de-identified data through collaborations with researchers, companies, and other parties involved inadvancing solutions for PWS.

9th IPWSO Conference | 35

6.2 - Multidisciplinary outpatients clinic for adults with Prader-Willi syndrome: the Rotterdam
experience
Dederieke A.M. Maes-Festen1,2, Anita C.S. Hokken-Koelega2,3; Stephany H. Donze3; Renske J.
Kuppens3, Laura C.G. de Graaff2,3
1

Ipse-de Bruggen, the Netherlands, 2 Erasmus Medical Center Rotterdam, the Netherlands, 3Dutch
Growth Research Foundation, Rotterdam, the Netherlands
Introduction Health issues in people with Prader-Willi Syndrome (PWS) show a wide variability,
ranging from mild, to complex and severe. In the Netherlands, multidisciplinary health care for PWS
children is well organized. However, for adults, multidisciplinary care is not available. Since part of thehealth problems in PWS can be prevented by good medical support, we have launched amultidisciplinary outpatients clinic (OPC) for adults with PWS. This PWS-OPC is part of the Dutch
National Expert Center for PWS, a collaboration between the university hospitals of Nijmegen,
Maastricht and Rotterdam which is currently being launched. The aim of the OPC is to improve qualityof life of adults with PWS by 1. treating underdiagnosed health issues 2. supporting patients andcaregivers in dealing with behavioral problems 3. to treat obesity using a specialized diet.
Methods The multidisciplinary PWS-OPC took place in the Erasmus MC of Rotterdam. All patients
visited the endocrinologist, the physician for people with intellectual disabilities, the pedagogistpsychologist and the dietitian. Before the first visit, we asked all the patients for their expectations
regarding the multidisciplinary visit. During the visit, we collected data regarding age, sex, genetic
subtype, living situation and medication, including growth hormone (GH) treatment, past and current
health problems, as well as behavioral problems. Data of complete physical examination including
blood pressure, BMI, PWS-related physical characteristics, edema and skin picking scars were alsocollected. After the visit, we collected laboratory data considering hematology, kidney function, liverfunction, electrolytes and pituitary hormone levels and we handed out patients satisfaction
questionnaires.
Results We will present data of the first 40 patients visiting the multidisciplinary PWS-OPC. Patientswere either young adults from the children’s cohort of the Dutch Growth Research Foundation, or new
patients referred by the General Practitioner. We will show an overview of demographic data,
frequencies and types of past and current medical treatment, behavioral problems as well as physicalparameters. Furthermore, we will report on pharmacological treatments (including psychiatric
medication), behavioral, physical and biochemical data. We will present all relevant parameters
according to genetic subtype and the presence or absence of GH treatment. Finally, we will show theresults of the patients' satisfaction questionnaires as a tool for colleagues who want to launch a similar
multidisciplinary OPC.
Conclusion Within the Erasmus MC, we have launched a new multidisciplinary outpatients clinic for
adults with Prader-Willi syndrome. As expected, patients on GH treatment had less physical problems
and less behavioral problems than GH-naive individuals. Hypogonadism was the main underdiagnosed
health issue. Satisfaction questionnaires show that patients appreciate both the medical, behavioral andnutritional support.
Summary: We have launched a new outpatients clinic (OPC) in Rotterdam, the Netherlands, where
adults with PWS are supported by a team of PWS experts. We will show the (anonymized) data of thefirst 40 patients and show their opinion regarding the OPC.

36 | 9th IPWSO Conference6.3 - Venous Thromboembolism in Prader-Willi Syndrome: A Questionnaire Survey
Ann M. Manzardo1, Merlin G. Butler1, Janalee Heinemann2, Barbara McManus2, Carolyn Loker2,
James Loker3
1

Departments of Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical
Center, Kansas City, KS; 2Prader-Willi Syndrome Association (USA), Sarasota, FL; 3Department ofPediatrics, Bronson Hospital, Western Michigan University, Kalamazoo, MI.
Introduction: Prader-Willi Syndrome Association (USA) monitors the ongoing health and welfare ofindividuals with PWS through active communication with members, membership surveys and dataregistries (e.g., Causes of Death Registry established in 1973). Pulmonary embolism has recently
emerged in clinical studies and data reviews as a significant risk factor for injury and death in PraderWilli syndrome (PWS). Prader-Willi Syndrome Association (USA) conducted a survey of its
membership to advance understanding and further characterize the frequency, risk and protective
factors of thromboembolism in PWS.
Methods: A 66-item questionnaire probing the frequency of venous thromboembolism, pulmonary
embolism and related characteristics including obesity, health problems, medications and family
history of clots was developed by a panel of PWS medical and scientific experts with input from
Prader-Willi Syndrome Association (USA) leadership. The survey was administered electronically to
the Prader-Willi Syndrome Association (USA) membership with confirmed and active e-mailaddresses. An interim analysis of descriptive data including means, standard deviations and frequenciesof blood clots was carried out on data from the first round of respondents. The characteristics of thosewith and without reported history of blood clots were tabulated and compared.
Results: Interim results from 539 current responders (277 females, 262 males) identified 22 (4%; 14
females, 8 males) individuals with a history of blood clots. There were no differences in gender, but
individuals with clots were significantly older 27.6±16yrs v 18.2±12yrs (F=12, p<0.001) and more
likely to have a reported history of obesity (N=16, 76%), edema (N=13, 59%), hypertension (N=5,24%), vasculitis (N=6, 33%) and family history of blood clots (N=7, 33% with clots; N=73, 15%
without clots, χ2=4.9, p<0.03) than individuals without clots. Individuals with clots were less likely tohave received growth hormone (N=10, 45% with clots vs N=408; 81% without clots, χ2=16, p<0.0001)
than individuals without clots.
Summary: The preliminary results suggest an increased risk of venous thromboembolism in PWS withincreased age, obesity history, lower extremity edema, vasculitis, and family history of clots. Further
study is needed to evaluate the effectiveness of interventions such as weight loss, anticoagulation, risks
associated with genetic predisposition and PWS subtype and potential benefits of growth hormone
therapy on the causation and development of thromboembolism in PWS.

9th IPWSO Conference | 37

6.4 - A PWS clinic – is it worth the effort?
Franklin JL*, Manson E*, Loughnan G*, Picone T*, Markovic T*#*Metabolism and Obesity Services, RPA Hospital, Sydney Australia;# Boden Institute, University of Sydney, Sydney Australia
Prader-Willi Syndrome (PWS) is a genetic syndrome associated with severe obesity and a historic life
expectancy of late 20s. PWS obesity results from an energy imbalance influenced by hypothalamic
dysfunction. People with PWS have cognitive limitations, emotional immaturity and often demonstrate
behavioural outbursts. Maintaining health in this population is difficult and commonly requires
unpopular strategies. Medical presentations can differ markedly from the general population, thus
complicating or delaying management. Given the complexities of this syndrome, we sought to identify
a successful model of care for people with PWS. Evaluation of the PWS clinic in a large Australianpublic teaching hospital was undertaken to determine if a specific clinic achieves meaningful outcomesfor clients with PWS and their families/carers and to determine what methods were most effective inthe treatment of their obesity. Data collected over 24 years was used to determine weight and healthoutcomes.
Eighty six patients diagnosed with PWS have attended the clinic, 46 of whom have attended regularly.
The mean age was 30 yrs (range 11 to 59) with 5 patients >50yrs (to December 2015). 20% of patientsare currently in the healthy or overweight range. The mean maximum BMI of the patients was
47kg/m2 and the mean BMI of the clinic population at present is 40 kg/m2 (range 22 – 76). Of thecohort 17 have died, five of whom resided in appropriate residential care. 81% of deaths were fromobesity related complications.
Residential care was the most important marker for successful treatment. Restrictive practices,consistent management and home-based exercise equipment contributed to superior results.
Preliminary carer feedback indicated specialised healthcare, training of caregivers and advocacy werethe most beneficial components of the clinic.
Summary: A specialised PWS clinic effectively addresses the complex needs of this population. It also
provides support and education for their families, caregivers and health professionals contributing togreater longevity and improved health for the client.
	
  
	
  
	
  

38 | 9th IPWSO Conference6.5 - Multicenter study of early screening and prevention of Prader-Willi Syndrome
LU Wei1, CHEN Chao2, YAO Jianhong3, WANG Weiqiong4, WEI Qiufeng5, YANG Xiaoyan6, LI
Zhankui7, ZHOU Xiangming8, LIU Jiangqin9, DONG Lijie10, TONG Xiaomei11, KANG Wenqing12,
LUO Feihong1
1 Dept of Pediatric Endocrinology and Inherited Metabolic Diseases, and 2 Dept of Neonatology,
Children’s Hosp. of Fudan University, Shanghai 3 Dept of Neonatal Intensive Medicine, Children’s
Hosp. of Shanxi Province, Taiyuan 4 Dept of Neonatology, Boai Hosp. of Zhongshan City, Guangdong
5 Dept of Neonatology, Maternal and Child Health Care Hosp., Guangxi Zhuang Autonomous Region
6 Dept of Neonatology, West China Women’s and Children’s Hosp., Chengdu 7 Dept of Neonatology,
Maternal and Child Health Care Hosp. of Shaanxi Province 8 Dept of Neonatology, Maternal and Child
Health Care Hosp. of Jiaxing City, Zhejiang Province 9 Dept of Neonatology, Shanghai First Maternal
and Infant Health Care Hosp., 10 Intensive Care Center, Harbin Children’s Hosp., Heilongjiang
Province 11 Dept of Pediatrics, Peking University Third Hosp. 12 Dept of Neonatology, Zhengzhou
Children’s Hosp., Henan Province, China
Background: The current diagnostic criteria for Prader-Willi syndrome (PWS) is proposed by Holmet.al. in 1993. Although the criteria are widely accepted, it was challenging to be implemented in
Chinese population.The present study collected PWS cases from 12 centers across China. By analyzing
the clinical manifestation during early infancy, we aimed to provide data for clinical characteristics,
screening strategy and effect of growth hormone (GH) treatment in Chinese PWS patients.
Methods and Results: We screened 63 suspected PWS cases in 11 centers from May-2012 to Aug2013 using MS-PCR. Patients diagnosed by MS-PCR further underwent analysis by MS-MPLA andSTR to identify PWS genetic markers. Data on patients’ history, clinical manifestation,
anthropometrics and clinical biochemistry test before/after GH treatment were collected foranalysis.Among our enrolled subjects, 16 were confirmed by MS-PCR. Further analysis using MSMLPA and STR analysis showed that 13 were associated with paternal deletion while the rest 3 werematernal uniparental disomy (mUPD). Among the 16 diagnosed PWS, 13 were delivered at full term, 1
were preterm birth, 2 postterms, 4 delivered vaginally, 12 delivered by cesarean section. Fetal distress
was diagnosed in 10 cases while abnormal fetal position found in 5 cases. All patients had reduced fetal
movement, hypotonia and infant feeding difficulties. Characteristic facial appearance was found in 6
cases when 13 showed hypogonadism, 8 had hypopigmentation. There were 4 patients received rhGH
treatment. When we found patients treated with GH had improved physical development, no difference
was found in thyroid function, plasma IGF-1 levels, fasting blood glucose, fasting insulin levels andblood lipid levels.
Conclusions: PWS might account for 25% of infants with idiopathic hypotonia and infant feeding
difficulties. Screening using MS-PCR in suspected cases is critical to identify PWS patients.
Hypogonadism and hypopigmentation are important clues for diagnosis. GH treatment during infancy
can improve physical development in PWS patients, however how to improve cognitive development
and function of endocrine system in PWS patients requires future studies.
Summary: We screened 63 neonates suspicious of PWS with idiopathic hypotonia and feeding
difficulties among 11 Chinese centers during the period from May-2012 to Aug-2013. 16 wereconfirmed by genetic analysis, 13 with paternal deletion and 3 with maternal uniparental disomy. 4
patients treated with GH had improved physical development, no difference was found in thyroid
function, plasma IGF-1 levels, fasting blood glucose, fasting insulin levels and blood lipid levels.

9th IPWSO Conference | 39

P1. Ayabe, Tadayuki. Reduced cerebrospinal fluid orexin level in Prader-Willi syndrome patientswith excessive daytime sleepiness. Tadayuki Ayabe, MD, Mayu Omokawa, MD, Yuji Oto, MD, Maki
Fukami, MD, PhD, Nobuyuki Murakami, MD, Takashi Kanbayashi, MD, Toshiro Nagai, MD. National
Research Institute for Child Health and Development, Tokyo, Japan
P2. Galesanu, Corina. Hypogonadism in a Female with Prader Willi Syndrome. Case Report. Corina
Galesanu. University of Medicine and Pharmacy“Gr.T.Popa”, Iasi- Romania
P3. Oto, Yuji. Latent Central Adrenal Insufficiency may exist in some patients with Prader-Willi
syndrome. Yuji Oto, Keiko Matsubara, Tadayuki Ayabe, Nobuyuki Murakami, Tomoyo Matsubara,
Hiroyuki Ogata, Masao Gito, Hiroshi Ihara, Toshiro Nagai. Dokkyo Medical University Koshigaya
Hospital, Saitama, Japan
P4. Murakami, Nobuyuki. Association of atrophy and asymmetry of the paravertebral muscles withthe development of scoliosis in Prader-Willi syndrome. Nobuyuki Murakami, MD, Yuji Oto, MD,
Tadayuki Ayabe, MD, Tomoyo Matsubara, MD, Toshiro Nagai, MD. Dokkyo Medical University
Koshigaya Hospital, Saitama, Japan
P5. Vijaykumar, Padmavathi. Analysis Of Chromosomal Abnormalities And Genomic Imprinting
Gene At SNRPN- SNURF In Prader Willi Syndrome –Tamilnadu Population. Padmavathi Vijaykumar,
Keshavarao Sasikala and Vellingiri Balachandar. Department of Human Genetics and Molecular
Biology, School of Life Sciences, Bharathiar University, Coimbatore, India.
P6. Passone, Caroline. PWS in Brazil: 6 months follow-up in a reference center. Caroline de Gouveia
Buff Passone MD, Simone Sakura Ito MD, Ruth Rocha MD, Durval Damiani MD PhD. PediatricEndocrinologist Instituto da Criança- São Paulo University- Brazil
P7. Ito, Simone. Obese Prader-Willi versus Obese controls: Metabolic Profile in Brazilian Patients.
Simone Sakura Ito MD, Caroline de Gouveia Buff Passone MD, Ruth Franco Rocha MD, Durval
Damiani MD PhD. Pediatric Endocrinologist Instituto da Criança- São Paulo University- Brazil
P8. Salles, Juliette. Deficits in voice and multisensory processing in patients with Prader-Willi
syndrome. J. Salles, K. Strelnikov, C Mantoulan,D. Thuilleaux, V. Laurier, C. Molinas, M. Tauber and
P. Barone. Centre de Référence du Syndrome de Prader-Willi, Hôpital des Enfants, Toulouse,
INSERM, France
P9. Hasegawa, Tomoko. A Young Adult with PWS Encourages a Mother of a Baby with PWS by
Emails. Tomoko Hasegawa, Gaku Harada, Fumiko Harada, Tomoko Iwasaki. PWSA Japan
P10. Matsubara, Keiko. Risk assessment of medically assisted reproduction and advanced maternalages in the development of Prader-Willi syndrome due to UPD(15)mat. Keiko Matsubara*, Nobuyuki
Murakami, Maki Fukami, Masayo Kagami, Toshiro Nagai, and Tsutomu Ogata*. National ResearchInstitute for Child Health and Development, Japan
P11. Stegmann, Jorgelina. Are frequent the Cholethiasis in subjects with Prader Willi Syndrome?
Stegmann, Jorgelina; Quaglia, Federico C.A.,; Biasatti, Cintia; Ceccomancini, Romina; Paradiso, Alex
D. SPINE Foundation, Buenos Aires, Argentina
9th IPWSO Conference | 41

P12. Camblats, Anna-Malika. PRASOC project: Study of the cognitive capacities to process
emotional and social informations in the Prader-Willi syndrome. A.-M. Camblats, J. Maire, J.
Chevalère, S. Roux, S. Mathey, C. Bellamy, M. Glattard, M. Tauber, D. Thuilleaux, V. Laurier, F.
Besnier, & V. Postal. Université de Bordeaux, Bordeaux, France
P13. Diene, Gwenaelle. French experience of assessment of hyperphagia in PWS patients. G. Diene,
C. Molinas, S. Faye, I. Kieffer, M. Valette, M. Glattard, B. Jouret, S. Çabal-Berthoumieu, C. Noual, M.
Tauber. Centre de Référence pour le Syndrome de Prader-Willi; Hôpital des Enfants, Toulouse, France
P14. Kalarchian, Melissa. Weight Management for Youth with Prader-Willi Syndrome: Delivery toParents via Telemedicine. Melissa A. Kalarchian, PhD, Jennifer P. Elliott, PharmD, Khalid M. Kamal,
M. Pharm., PhD, Roxann Diez Gross, PhD, Heather Roach, MS, Gina Salvatori, RD, LDN, Gregory
Cherpes, MD. Duquesne University and the Children’s Institute of Pittsburgh, USA
P15. Achutegui, Irune. PWS & Self-Determination. Helping Parents & Teachers To Enhance Child
Resourses To Grow In Autonomy. Irune Achutegui. San Raffaele Hospital, Milan, Italy
P16. Bellamy, Caroline. First results of the larger study on the evaluation of the impact of cognitiveand executive abilities on socialization difficulties in childhood with PWS. Bellamy C., Glattard M.,
Camblats A., Chevalère J., Diene G., Cabal-berthoumieu S., Tricot J., Thuilleaux D, Besnier F.,
Chirossel C, Tauber M., Postal.V. Centre de Référence pour le Syndrome de Prader-Willi; Hôpital desEnfants, Toulouse, France
P17. Kato, Yoshiro. Manifestation of behavioral problems and BMI scores in person with PWS by age
groups, and living condition of adults with PWS in Japan. Yoshiro KATO a, Koji MINOSAKI. Kansai
University of Welfare Sciences, Japan
P18. Tauber, Maïthé. Cerebellar hyperperfusion in PWS patients: the link for satiety? C. Mantoulan,
PhD, P. Payoux, MD, K. Boulanouar, G. Diene, MD, M. Glattard, PhD, B. Rogé, PhD, C. Molinas, A.
Sevely, MD, P. Celsis, PhD, M. Tauber, MD. Centre de Référence pour le Syndrome de Prader-Willi;
Hôpital des Enfants, Toulouse, France
P19. Aman, Lucie. Psychosis in Prader-Willi syndrome. Lucie Aman, Katherine Manning, Anthony
Holland. University of Cambridge, UK
P20. Chevalère, Johann. Relationship between electrodermal activity and behavioural responses toinhibition and working memory updating tasks in Prader-Willi syndrome: A sub-section of the
PRASOC project. J. Chevalère, J. Jauregui, P. Copet, V. Laurier, D. Thuilleaux, A.M. Camblats, C.
Bellamy, M. Tauber, & V. Postal. Université de Bordeaux, Bordeaux, France
P21. Eggert, Rachelle. Muscle development and function in a Magel2 mouse model of Prader-Willi
syndrome. Rachelle Eggert, Ain A. Kamaludin and Rachel Wevrick. University of Alberta, Edmonton,
AB, Canada
P22. Debladis, Jimmy. Altered gaze behavior during face processing in patients with Prader-Willi
syndrome. J. Debladis, K. Strelnikov, C Mantoulan, J Salles, D. Thuilleaux, V. Laurier, C. Molinas, M.
Tauber and P. Barone. Centre de Référence du Syndrome de Prader-Willi, Hôpital des Enfants,
Toulouse, INSERM, France
42 | 9th IPWSO ConferenceP23. Wijesuriya, Methsala. Role of the Prader-Willi Syndrome protein MAGEL2 in intracellularpathways regulating the leptin receptor. T.Methsala Wijesuriya, K. Vanessa Carias, Leentje De
Ceuninck, Jan Tavernier and Rachel Wevrick. University of Alberta, Edmonton, AB, Canada
P24. Fountain, Michael. Elucidating the neurobehavioral phenotypes of Magel2-null mice. Michael D.
Fountain, Huifang Tao, Chun-An Chen, Jiani Yin, Christian P. Schaaf. Baylor College of Medicine,USA
P25. Sanderson, Matthea. Interactions between the Prader-Willi syndrome candidate protein
MAGEL2 and neuronal proteins. Matthea Sanderson, Herman Cortes, and Rachel Wevrick. Universityof Alberta, Edmonton, AB, Canada
P26. Wishnefsky,Elana. The Impact of Hyperphagia and Food Restriction on Siblings of Individuals
with Prader-Willi Syndrome. Elana Wishnefsky, Anne Matthews, Shawn McCandless, Michelle
Merrill, Aaron Goldenberg. Case Western Reserve University, USA
P27. Carias, Vanessa. The role of MAGEL2, a protein implicated in Prader-Willi syndrome, in theregulation of RING-zinc finger-type E3 ubiquitin ligases. Vanessa Carias and Rachel Wevrick.
University of Alberta, Edmonton, AB, Canada
P28. Woodcock, Kate. Characteristics of change triggered temper outbursts in children with PWS and
ASD and how these may impact on the efficacy of behavioural intervention strategies. Kate Anne
Woodcock, Clare McGeady, Glenda Preston, Áine Fitzpatrick, Nigel Robb, Katerina Dounavi & Leah
Bull. School of Psychology, Queen’s University Belfast
P29. Roof, Elizabeth. Beloranib Improves Hyperphagia-Related Behavior: Results from a Phase 3,
Randomized, Placebo-Controlled Clinical Trial of Beloranib in Patients with Prader-Willi Syndrome.
Elizabeth Roof, Jaret Malloy, Dongliang Zhuang, Nerissa Kreher, Elizabeth M Dykens. Vanderbilt
University, Nashville, TN, USA
P30. Even-Zohar, Noa. Parental approaches regarding prenatal diagnosis and termination ofpregnancy in Prader Willi syndrome. Noa Even- Zohar, Talia Geva-Eldar, Yehuda Polak, Harry Hirsch,
Itai Gross, Varda Gross-Tsur. Multidisciplinary Prader-Willi Syndrome Clinic, Shaare Zedek Medical
Center, Jerusalem, Israel
P31. Biliou, Vasiliki. Correlation Of Five Distinct Characteristics Of Prader-Willi Syndrome: A FourYear Case Study On A Daily (School Days) Basis. Biliou Vasiliki¹, Christina Theodoropoulou,
Efstratios Alexandrou. National Association of Prader-Willi Syndrome Hellas, Athens, Greece
P32. Chanioti, Eleni. Determinιng The Mathematical Profile Of A Child With Prader-Willi Syndrome
And Applying The Constructivism Model As A Learning Tool. Chanioti, Eleni. Scientific Advisor to
the National Association for Prader-Willi Syndrome Hellas, Greece
P33. Haqq, Andrea. Abnormal body composition phenotype in children with Prader-Willi Syndrome.
Camila E. Orsso, Michelle Mackenzie, Carla M. M. Prado, Angela Alberga, Andrea M. Haqq.
Department of Pediatrics, University of Alberta, Canada.
9th IPWSO Conference | 43

P34. Weisensel, Nicolette. Methylene tetrahydrofolate reductase (MTHFR) polymorphisms, genetic
subtype, psychiatric diagnosis and symptom severity in PWS adults residing in group homes. Nicolette
WeisenselMD, Marge Royle PhD, Linda Gourash MD and Janice Forster MD. Prader-Willi Homes of
Oconomowoc and Marion University, Wisconsin, USA
P35. Kimonis, Virginia. Early Diagnosis of Prader-Willi syndrome delays onset of obesity. Virginia
Kimonis, MD, Roy Tamura, June-Anne Gold, MD, Abhilasha Surampalli, Javeria Manazir, Jennifer L.
Miller, MD, Elizabeth Roof, MA, Elisabeth Dykens, PhD, Merlin G. Butler, MD, PhD, and Daniel J.
Driscoll, MD, PhD. University of California, Irvine, California, USA
P36. Stamm, Stefan. An oligonucleotide changes alternative splicing of the serotonin receptor 2C,
reduces food intake in mice and could substitute SNORD115. Zhaiyi Zhang, Marina Falaleeva andStefan Stamm, University of Kentucky, Lexington, KY, USA
P37. Forster, Janice. Von Economo neurons (VENs) in post mortem brains in PWS: a preliminary
report. Janice Forster MD, Merina Varghese PhD and Patrick Hof MD. Pittsburgh Partnership,
Pittsburgh, PA, USA
P38. Muscatelli, Francoise. Functional and therapeutical investigation of the oxytocin system in the
Magel2-deficient mouse model. Françoise Muscatelli, Valery Matarazzo, Fabienne Schaller,
Alessandra Bertoni, Marie-Solenne Felix, Laura Caccialupi, Claude Villard, Amélie M Borie, Michel
G. Désarmenien. Institut de Neurobiologie de la Méditerranée, Marseille, France.
P39. Mathieux, Elodie. An in vitro model of Prader-Willi Syndrome by generation of hypothalamic
neurons and genome editing of induced pluripotent stem cells. Elodie Mathieux, Erin Banda, Chris
Stoddard, Heather Glatt-Deeley, Maeva Langouet, Leann Crandall and Marc Lalande. Stem Cell
Institute and Institute for Systems Genomics University of Connecticut, Farmington, CT, USA
P40. Melki, Judith. Truncating Mutations of MAGEL2, a Gene within the Prader-Willi Locus, Are
Responsible for Fetal Akinesia and Arthrogryposis. Dan Mejlachowicz, Flora Nolent, Jérome
Maluenda, Hanitra Ranjatoelina-Randrianaivo,Fabienne Giuliano, Ivo Gut, Damien Sternberg, Annie
Laquerrière, and Judith Melki. Inserm and University of Paris-Saclay, Le Kremlin Bicêtre, France
P41. Manning, Katherine. Brain and Behaviour in PWS. Katherine Manning, Roger Tait, John
Suckling, Howard Ring, Anthony Holland. University of Cambridge, UKP42. Woodcock, Kate. The development of resistance to change in individuals with PWS. Kate Anne
Woodcock & Elaine Laura Haig. School of Psychology, Queen’s University Belfast
P43. Mahoney, Carrie E. Oxytocin neurons promote arousal in a mouse model of PWS. Carrie E.
Mahoney, PhD, Valery Grinevich, MD, PhD, and Thomas E. Scammell, MD. Beth Israel Deaconess
Medical Center, Harvard Medical School, USA
P44. Salehi, Parisa. Abnormal Videofluoroscopic Swallow Studies (VFSS) in Infants with PraderWilli Syndrome Indicate a High Rate of Silent Aspiration. Parisa Salehi, MD, Maida Chen, MD, Anita
E. Beck, MD, PhD, Amber McAfee, ARNP, Soo-Jeong Kim, MD, Lisa Herzig, MD, Anne Leavitt,
MD. Seattle Children’s Hospital, Division of Endocrine, University of Washington, USA
44 | 9th IPWSO ConferenceP45. Tam, Joseph. Role of the Endocannabinoid System in Prader-Willi Syndrome. Ibrahim Knani,
Brian J. Earley, Shahar Azar, Saja Baraghithy, Shiran Udi, Anna Permyakova, Rivka Hadar, Daniela P.
Reyes-Capo, Harry J Hirsch, Talia Eldar-Geva, Itai Gross, Andrea M. Haqq, Joan C. Han, Varda
Gross-Tsur, Rachel Wevrick, Joseph Tam. The Hebrew University of Jerusalem, Jerusalem Israel
P46. Diez Gross, Roxann. Discovery of Dysphagia in Children and Adults with Prader-Willi
Syndrome. Roxann Diez Gross PhD, CCC-SLP, Ronit G. Gisser, MSc, CCC-SLP, Gregory L. Cherpes,
MD, Katie Hartman, MA, CCC-SLP, Rishi Maheshwary, MD. The Children’s Institute of Pittsburgh,
Pittsburgh, Pennsylvania, USA

9th IPWSO Conference | 45

P1 - Reduced cerebrospinal fluid orexin level in Prader-Willi syndrome patientswith excessive daytime sleepiness
Tadayuki Ayabe, MD1,2, Mayu Omokawa, MD3, Yuji Oto, MD2, Maki Fukami, MD, PhD1, Nobuyuki
Murakami, MD2, Hiroshi Ihara, Professor4, Takashi Kanbayashi, MD3, Toshiro Nagai, MD2,5
1Dept of Molecular Endocrinology, National Research Institute for Child Health and Development, Tokyo,

Japan; 2Dept of Pediatrics, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan; 3Dept of
Neuropsychiatry, Akita University Graduate School of Medicine, Akita, Japan; 4Dept of Psychiatry, Dokkyo
Medical University Koshigaya Hospital, Saitama, Japan; 5Nakagawanosato Ryoiku Center, Saitama, Japan.

Background: Patients with Prader-Willi syndrome (PWS) often show excessive daytime sleepiness(EDS). The pathogenic mechanism is assumed that obstructive sleep apnea syndrome andhypothalamic dysfunction are both implicated. Orexin (known as hypocretin) is a hypothalamic
neuropeptide known to present in lower levels in the cerebrospinal fluid (CSF) of patients with sleep
disorders such as narcolepsy compared with healthy individuals. The objectives of this study are toinvestigate the reduction in CSF orexin concentration, and the relationship between the severity of EDS
and CSF orexin concentration in Japanese PWS patients.
Methods and Results: The CSF orexin levels were evaluated in 12 patients (9 males and 3 females) of
the Pediatric Department of Dokkyo Medical University Koshigaya Hospital. The genotypes were all
chromosome 15q deletion. The median age at the time of the CSF sample was 21.5 years old with an
IQR of 16.2–28.2 years. Their median Epworth sleepiness scale (ESS) score of 12 subjects was 10.0
(IQR 3.3–13.8), and 6 subjects (50%) had an ESS score ≥ 11 (criterion for pathological EDS). The
median CSF orexin level of these 12 subjects was 192.0 pg/mL with an IQR of 159.5–235.8 pg/mL.
Based on the standard values (normal: ≥200 pg/mL, intermediate: 110 to 200 pg/mL, low: ≤110
pg/mL), seven of the 12 subjects (58%) exhibited below normal concentrations, including 7 subjects
with intermediate levels. A multiple regression model with the ESS score as the outcome variable andthe CSF orexin concentration and other variables as explanatory variables was generated. A Wald test
revealed that CSF orexin concentration could significantly explain the ESS score (regression
coefficient -0.098, p = 0.003).
Conclusions: Reduced CSF orexin concentration was noted in about three-fifths of Japanese PWS
patients. A significant correlation was observed between ESS score and CSF orexin concentration. The
present study suggests that reduced CSF orexin contribute to severity of EDS in Japanese PWS
patients.
Summary: At least some of Japanese PWS patients have insufficient orexin function in brain. The
lower the CSF orexin concentration is, the worse daytime sleepiness PWS patient has.

9th IPWSO Conference | P1

P2 - Hypogonadism in a Female with Prader Willi Syndrome. Case Report
Galesanu Corina
University of Medicine and Pharmacy“Gr.T.Popa”, Department of Endocrinology, Iasi- Romania
Background: Prader-Willi syndrome (PWS) is a genetic disorder characterized by mental retardation,
dysmorphic features, and behavioral dysfunction, most notably food-related problems such as
hyperphagia, food seeking, and a high risk for obesity. Clinical features are attributed mainly tohypothalamic dysfunction. The main phenotypic features include neonatal hypotonia and feedingproblems; hypogonadism, hyperphagia, and obesity; short stature; and characteristic facial appearances.
Individuals with PWS have mild to moderate intellectual disability.
Case presentation: A girl at 16 years old was presented at the consultation with her mother for theabsence of the cycle. At a first inspection a young obese with low stature. Height=147cm (-2.0 SDS),
Weight = 74.5kg (+2.5 SDS), BMI= 34.4 Kg/m2. Clinical examination of sexual characters: poorly
developed for age: Tanner stage I breast development and Tanner stage I/II pubic hair. Menses had not
yet started. Laboratory routine investigations: urea and electrolytes, liver function tests, calcium, andphosphate were normal. A fasting and a 2-hour post-prandial blood sugar were normal. Thyroid andadrenal function were normal. Serum levels of LH and FSH was abnormally low <1.0 IU/l. The
karyotype of the patient's mother and father were normal. The girl, at genetics consult subsequentchromosome studies revealed a deletion in chromosome 15, positive for Prader-Willi syndrome. At
psychiatric examination, she was found to be functioning in the borderline area of subnormality IQ76.
History: She was born at term, with Apgar of 7. Her birth weight was 2830 g, and birth length was 49cm. She had poor initial respiration, genital hypoplasia and she was hypotonic and quiet. The latest
submitted to the school difficulties with psychiatric records for behavior problems. Sex hormone
treatmenthasbeen
initiatedwithtransdermal
estradiol.
Discussion and Conclusions: We presented a case of PWS, diagnosed later than having regard as thefirst distinctive sign hypogonadism. The clinical expression of hypogonadism in females with PWS isvariable: genital hypoplasia, delayed and incomplete pubertal development. Although some femaleswith PWS undergo spontaneous menarche, most have primary or secondary amenorrhea oroligomenorrhea. Primary ovarian dysfunction is an important contributor to the hypogonadism inwomen with PWS. Sexual development is incomplete in most PWS patients, consistent with arrested
pubertal development.
Summary: Early diagnosis and treatment in women with PWS and hypogonadism can improve qualityof life for these persons.

P2 | 9th IPWSO ConferenceP3 - Latent Central Adrenal Insufficiency may exist in some patients with Prader-Willi syndrome
Yuji Oto 1, Keiko Matsubara 2, Tadayuki Ayabe 2, Nobuyuki Murakami 1, Tomoyo Matsubara 1,
Hiroyuki Ogata 3, Masao Gito 3, Hiroshi Ihara 3, Toshiro Nagai 4,
1, Dokkyo Medical University Koshigaya Hospital, Department of Pediatrics, Saitama, Japan; 2, National
Research Institute for Child Health and Development, Department of Molecular Endocrinology, Tokyo, Japan;
3, Dokkyo Medical University Koshigaya Hospital, Department of Psychiatry, Saitama, Japan; 4,Nakagawanosato Ryoiku Center, Saitama, Japan[Background] The annual death rate of Prader-Willi syndrome (PWS) is reported to be as high asaround 3%. The causes of deaths in children are often sudden and unexplained. Several reports
hypothesized that patients with PWS may have latent central adrenal insufficiency (CAI). However, itremains unclear whether PWS subjects are suffered from an alternation of the HPA (HypothalamusPituitary-Adrenal; HPA) axis or not. The aim of this study was to explore the HPA axis in our PWS
patients.
[Methods and Results] We evaluated the HPA axis in our PWS patients (24 males and 12 females, aged
0.7-59 years) using insulin tolerance test. In addition, we presented clinical features of five cases whoare suspected to have CAI. All 36 patients showed normal basal ACTH (12.9 ± 8.0 pg/ ml), cortisol(17.5 ± 8.5 µg/dl) and serum cortisol response (20.8 ± 8.5µg/dl) to insulin tolerance test. However, 25
of 36 patients showed delayed response of peak cortisol levels (120 minutes after stimulation). In
addition, in the presented five cases, several clinical manifestations such as status epilepticus, lethargy
and cardiopulmonary arrest were seen. Four of five patients showed hyponatremia and low serum IGF1 level (Na 122, 125, 135 and 121 mEq/l , IGF-1 8, 21, 6 and 19 ng/ml, respectively).
[Conclusion] We should consider the existence of CAI and evaluate the adrenal function in cases ofhyponatremia with unexplained neurological symptoms.
[Summary] We should treat with steroid if CAI is suspected clinically, even though laboratory data do
not indicate CAI. Especially, patients with under nutrition (low level of IGF-1) should be carefully
monitored.

9th IPWSO Conference | P3

P4 - Association of atrophy and asymmetry of the paravertebral muscles with the development ofscoliosis in Prader-Willi syndrome
Nobuyuki Murakami, MD1, Yuji Oto, MD1, Tadayuki Ayabe, MD1, Tomoyo Matsubara, MD1, Toshiro
Nagai, MD2
1Department of Pediatrics, Dokkyo Medical University Koshigaya Hospital, Saitama, Japan, 2Nakagawa-No-Sato
Hospital for the Disabled, Saitama, Japan

Background: Scoliosis is one of the most serious complications of Prader-Willi syndrome (PWS). The
incidence of scoliosis is significantly higher than that of idiopathic scoliosis in PWS. Poor strength in
the paravertebral muscles is considered to be a factor that exacerbates scoliosis in PWS. However, themechanism underlying the development of scoliosis in PWS remains unknown. In the present study, we
aimed to investigate whether atrophy or asymmetry of the paravertebral muscles is a cause or a resultof scoliosis in PWS.
Methods and Results: Thirteen patients (10 males and 3 females; age range, 6–19 years) with PWS(deletion type, n = 7; uniparental disomy type, n = 6) were examined. All patients were receiving
growth hormone (GH) therapy, and had developed scoliosis during GH therapy. Cobb angles were
measured every 6 months, to evaluate the degree of scoliosis. At each assessment, a single slice CT
scan was obtained at the level of the umbilicus, to evaluate paravertebral muscle volume.
The age at which scoliosis developed ranged from 2 to 15 years (median, 5 years). The duration
between starting GH treatment and developing scoliosis ranged from 1 month to 6 years and 7 months(mean, 2 years). Paravertebral muscle atrophy with fatty change was observed in 7 patients prior to thedevelopment of scoliosis. Asymmetry of the paravertebral muscles (>5% difference between right andleft paravertebral muscle volume) was observed in 4 patients prior to the development of scoliosis.
Conclusion: Abnormalities of the paravertebral muscles (atrophy with fatty changes or asymmetry)were observed in a substantial proportion of patients with PWS, before they developed scoliosis. Thisfinding suggests that these abnormalities of the paravertebral muscles are not a result of scoliosis.
Instead, paravertebral muscle atrophy with fatty changes or asymmetry could be causally related toscoliosis in PWS.
Summary: Atrophy or asymmetry of the paravertebral muscles could be a cause of scoliosis in PWS.

P4 | 9th IPWSO ConferenceP5 - Analysis of Chromosomal Abnormalities and Genomic Imprinting Gene at SNRPN- SNURF
in Prader Willi Syndrome –Tamilnadu Population.
Padmavathi Vijaykumar1, Keshavarao Sasikala2 and Vellingiri Balachandar1,2
Human Molecular Genetics and Stem Cell Laboratory, Department of Human Genetics and Molecular
Biology, School of Life Sciences, Bharathiar University, Coimbatore, India.
Background
Praderwilli syndrome (PWS) is a neuro-genetic disorder characterized by low birth weight, severe
hypotonia and feeding difficulties in early infancy, followed by hyperphagia and obesity starting inearly childhood. Short stature, small hands and feet, narrow bifrontal diameter, almond-shaped eyes,triangular mouth, a temper tantrums, motor milestones and speech delayed, in both sexes
hypogonadism. Many of the characteristic features of PWS result from the loss of function ofpaternally imprinted genes including SNRPN-SNURF, NDN and a cluster of snoRNAs. Their silencing
on the maternal chromosome is mainly attributed to DNA methylation and histone modifications at the
PWS- Imprinting center (IC) conferred by the Angelman syndrome (AS)-IC, which together form abipartite IC regulating the imprinted status of this region. The aim of the present study was toanalyze the chromosome abnormalities and paternally imprinted genes of SNRPN-SNURF
expression at chromosome region 15q11-q13 of PWS patients in Tamil Nadu population.
Methods and Results:
Totally 6 samples were selected including 3 PWS patients and their parents and equal number ofcontrols and PBLC culture and genomic DNA extraction from peripheral blood to execute molecular
screening of PWS. We reported PWS patients were exposed to have the predictable higher degree ofchromosomal aberrations karyotypes of del(15) (pter> q11::q13 >qter). Methylation specific – PCR
assay were revealed high quantity loss of paternal methylation at SNRPN gene to confirmed diagnosis
of PWS.
Conclusion:
We observed that the identification of cytogenetic abnormalities is not only important for providing a
cause for the PWS in a single individual but is also critical for accurate counseling regarding
recurrence risks to parents and family members. We suggest that SNRPN might represent a major
susceptibility gene for PWS.
Summary:
In our pilot study, cytogenetic and molecular screening studies are to facilitate investigation ofpaternally imprinted genes distribution of PWS, which is adjustment of the guidelines for preventive
management in adulthood.

9th IPWSO Conference | P5

P6 - PWS in Brazil: 6 months follow-up in a reference center
Caroline de Gouveia Buff Passone MD, Simone Sakura Ito MD, Ruth Franco Rocha MD, Durval
Damiani MD PhD
Pediatric Endocrinologist Instituto da Criança- São Paulo University- Brazil
Background
Prader-Willi Syndrome (PWS) patients have been followed in our country in different ways but we do
not have a society or a reference center to spread adequate information about the disease.
In January 2015, we started a PWS reference center in Sao Paulo University to promote a better carefor patients and families and to support them with a multidisciplinary team.
Methods
Forty two patients, between 2 and 21 years old, were followed for a 6 month period in our PWS
clinic. Body mass index-SDS (BMI-SDS) was evaluated at the beginning and after 6 months and thesedata were compared. The following items were analyzed: 1) use of growth-hormone 2) metabolic
profile: LDL, triglycerides, glycated hemoglobin (HbA1c), fasting glucose and insulin levels. 3)
polysomnography. All patients received orientation in diet (900 calories/day independent of wheight),
physical activity and behavior. Our team is composed by pediatric endocrinologist, dietician, nurses;
neurologist specialized in sleep disorders and otorhinolaringologist.
Results
The mean age was 9.8±5.2DP. BMI-SDS at the first visit was 2.8±1.9DP and after
6months 2.41±1.8DP. Metabolic profile showed that 21.6% patients had high LDL-c level (LDLc> 130mg/dL), 48.6%
had
low
HDL-c
level
(<40mg/dL),
18.6%
had
hypertriglyceridemia (>150mg/dL), 23.5% had high A1c (≥5.8%) and 44.8% had insulin
resistance. Only 12 patients used rhGH at the first visit and at the latest we had 29 (69%) patients on
rhGH use. The reason that thirteen patients were not in use of rhGH is due topolysomnography alterations and patients were waiting for surgery or CPAP. Polysomnography
revealed that 47.8% patients had an apnoea-hypopnoea index (AHI) >5 events/hour , 20.8% had O2
saturations under 92% and 56.5% had reduced sleep efficacy.
Conclusions
Most of our patients could lose weight with the correct approach in diet, behavior and physical activity.
The use of rhGH was increased after the beginning of the clinic and the benefit of this therapy is wellknown in the literature. Alterations in polysomnography were a major problem revealed in the follow
up and the correct approach of the multidisciplinary team is essential to support this disorder.
Summary
To start a PWS reference center in Sao Paulo – Brazil was the first step to promote a better care for
PWS patients and families. Our team could support them with the correct approach in diet, rhGH use
and all others disorders related to the syndrome.

P6 | 9th IPWSO ConferenceP7 - Obese Prader-Willi versus Obese controls: Metabolic Profile in Brazilian Patients
Simone Sakura Ito MD, Caroline de Gouveia Buff Passone MD, Ruth Franco Rocha MD, Durval
Damiani MD PhD
Pediatric Endocrinologist Instituto da Criança- São Paulo University- Brazil
Background: Prader Willi syndrome is a rare condition (1:15000) that starts with intense hypotonia in
the first years of life to reach a condition of voracious appetite which leads to life
threatening obesity. The obese Prader Willi syndrome patient (OPWS) has peculiar characteristics
which could confer different metabolic profiles compared with obesity of other causes. The aim of thisstudy is to describe and compare the metabolic profile in obese patients and OPWS patients followed ina Pediatric Endocrinology outpatient unit.
Methods: We evaluated in a cross-sectional study 45 obese patients and 22 OPWS between 8 and 20
years old and compared them according to cholesterol levels, triglycerides, glycated hemoglobin(HbA1c) and fasting glucose.
Results: The mean age of the 67 patients was 14.1 (±3.2) years old, 45 were male and the mean BMI ZSCORE was +3.1SD (±0.6SD). Both groups did not differ in sex, age and BMI Z SCORE. The
metabolic profile in OPWS versus obese patients showed: high LDL-c level (LDL-c≥ 130mg/dL) in
18.2% X 11.1%, low HDL-c level (<40mg/dL) in 36,4% X 46,7%, hypertriglyceridemia (≥150mg/dL)
in 13.6% X 24.4%, respectively; Probably due to the low number of patients, there was no significant
difference between both groups. However, there was a significant difference (p<0.001) in abnormal
Hb1Ac (≥5.8%) between OPWS (73.3%) and obese patients (7.1%). Only 1 patient in each group hadhigh fasting BLOOD glucose (>100mg/dL).
Conclusion: The comparison between obesity in Prader Willi syndrome and in other patients shows that
HbA1c tends to be higher in OPWS. The differences in lipid levels show a tendency of more elevatedlevels in OPWS but the number of patients is small to reach statistical significance.
Summary:
The comparison between obesity in Prader Willi syndrome and in other patients shows that HbA1c
tends to be higher in OPWS and there was no difference in lipid levels.

9th IPWSO Conference | P7

P8 - Deficits in voice and multisensory processing in patients with Prader-Willi syndrome
J. Salles, K. Strelnikov, C Mantoulan,D. Thuilleaux, V. Laurier, C. Molinas, M. Tauber and P. Barone
Centre de Référence du Syndrome de Prader-Willi, Hôpital des Enfants, Toulouse, INSERM, Centre dePhysiopathologie Purpan, Toulouse, Hôpital Marin d’Hendaye, Cerveau et Cognition, CNRS France.
Background. Neuropsychological studies have reported that patients with Prader-Willi syndrome(PWS) display altered social interactions with a specific weakness in interpreting social informationand in responding to them, a feature also observed in autism spectrum disorders (ASD). Based on the
hypothesis that atypical multisensory integration such as face and voice interactions would contributein PWS to social impairment we investigate the abilities of PWS to process communication signals
including the human voice.
Methods: 21Patients with PWS were recruited from the national reference center for PWS. In parallel,
21 typically developing (TD) individuals were also selected and recruited to be age- and gendermatched with the PWS cohort. In addition, a second set of five PWS patients was recruited to complete
the genetic subgroup of patients presenting with UPD. They performed two tasks. Firstly a simple
reaction time (RT) task of stimuli presented in uni- or bimodal condition and the task was to respond as
fast as possible to the stimulus by pressing a response key. Secondly a 2 AFC voice recognition taskthat consisted of discriminating a human voice (laughing, coughing, vocal sounds) from naturalenvironmental sounds.
Results. Compared to control typically developing individuals, PWS present low d-prime values
reflecting a specific deficit in discriminating human voices from environmental sounds. Further, while
PWS present some degree of multisensory benefits as expressed as a shortening of bimodal RT, thisaudiovisual gain was much lower than that of the TD. Moreover PWS display an absence of violationof the race model indicating a lack of convergence and integration of multisensory information prior to
the initiation of the behavioral response. All the deficits observed in patients with PWS were stronger
for the subgroup of those presenting Uniparental Disomy compared with those with chromosomal
deletion , fitting with the fact that they are more sensitive to ASD.
Conclusion. Altogether, our study suggests that the deficits in social behavior observed in PWS derive
at least partly from an impairment in deciphering the social information carried by voice signals, face
signals, and the combination of both. In addition, our work is in agreement with the brain imaging
studies revealing an alteration in PWS of the "social brain network” including the region involved inprocessing human voices.
Summary. In the present study, we were able to reveal specific deficits in patients with PWS using
simple tasks and natural stimuli having high ecological value, such as human voices.

P8 | 9th IPWSO ConferenceP9 - A Young Adult with PWS Encourages a Mother of a Baby with PWS by Emails
Tomoko Hasegawa, Gaku Harada, Fumiko Harada, Tomoko Iwasaki
1. Clinical Geneticist, Genetic Support and Consultation Office 2. Self-Advocator 3. Mother, peer-supporter 4.
Medical translator, PWSA Japan

Background
Mothers of a baby with PWS in Japan usually receive support from professionals and peer parents.
However, an adult person with PWS taking part in supporting a mother of an infant with PWS is not acommon practice.
ReportThis report introduces email interactions between a young adult male person with PWS and a mother ofa baby with PWS. Fumiko Harada is a mother of a young adult with PWS, Gaku (co-author). She wasgiving peer support to a young mother of a 3-year-old girl Mi (assumed name) with PWS, who asked
questions if Gaku ever felt it was hard to have PWS himself, and what kind of times he had felt thatway. In response to this, Gaku’s mother suggested her son that he should answer the questions byhimself. Gaku answered the questions of Mi’s mother and gave advice from the perspective of a personwith PWS with an insight into himself and the syndrome. Gaku wrote Mi’s mother that she needed todiscard the anxiety as the baby was able to read the mother’s mind. Gaku hoped Mi’s mother to treat
her daughter as a normal child, and not as a ‘PWS child’. He also gave advice on overeating that one
should not hold oneself too much from eating and that a mother should give her child a lot of love
instead of worrying.
Results
The mother of Mi was thankful for Gaku and was encouraged by him. She wrote Gaku that she wasgoing to try not to build up her stress, and find what her daughter can enjoy more than eating. Reading
Gaku’s email, his mother (Fumiko Harada) was pleased how her son had been thinking deeply, and thathe could think about other person’s feelings. Knowing what is in his mind better, they became able tobuild a better relationship. These changes made her feel much more relaxed than before, and treat andspeak differently. When difficult situations arise, she could now overcome them because she was able
to wait.
Conclusions
In this report, the person with PWS was given an opportunity to objectively understand himself.
Support by people with the same syndrome had been regarded as difficult, as they could be quite
egocentric and have weak self-insight. But this case showed it may be possible. Positive advice frompersons with PWS will encourage parents who are anxious about their children’s future.
Summary
We presented encouragement and advice by an adult with PWS to a mother of a baby with PWS. We
recommend advising under supervision of parents and/or caregivers as this could have positive impact
on the person with PWS as well as the mother of an infant with PWS.

9th IPWSO Conference | P9

P10 - Risk assessment of medically assisted reproduction and advanced maternal ages in thedevelopment of Prader-Willi syndrome due to UPD(15)mat
Keiko Matsubara*1,2, Nobuyuki Murakami2, Maki Fukami1, Masayo Kagami1, Toshiro Nagai2, andTsutomu Ogata*1,3
1

Department of Molecular Endocrinology, National Research Institute for Child Health and Development, Japan;
Department of Pediatrics, Dokkyo Medical University Koshigaya Hospital, Japan; 3Department of Pediatrics,
Hamamatsu University School of Medicine, Japan

2[Background] Recent studies have suggested that disomic oocyte-mediated UPD(15)mat is increasedin patients with Prader-Willi syndrome (PWS) born after medically assisted reproduction (MAR). It
remains unknown whether the increase is primarily due to MAR procedure itself or advanced maternal
childbearing ages as a predisposing factor for the disomic oocyte production.
[Methods and Results] We studied 122 naturally conceived PWS patients (PWS-NC group) and 13
MAR-conceived patients (PWS-MAR group). The relative frequency of disomic oocyte-mediated
UPD(15)mat was significantly higher in PWS-MAR group than in PWS-NC group (P=0.0045), and thematernal childbearing ages were significantly higher in PWS-MAR group than in PWS-NC group(P=0.0015). However, there was no significant association between the occurrence of disomic oocytemediated UPD(15)mat and MAR, after adjusting for childbearing age (P=0.25). Consistent with this,while the frequency of ART-conceived livebirths was higher in the PWS patients than in the Japanesegeneral population (6.4% vs. 1.1%, P=0.00018), the distribution of childbearing ages was significantly
skewed to the increased ages in the PWS patients (P<2.2×10-16).
[Conclusions] These results argue against a positive association of MAR procedure itself with thedevelopment of UPD(15)mat.
[Summary] We evaluated the effects of MAR and advanced maternal childbearing age in 135 Japanese
PWS patients including 13 MAR-conceived patients. The present study suggests that MAR is unlikely
to facilitate the disomic oocyte-mediated UPD(15)mat.

P10 | 9th IPWSO ConferenceP11 - Are frequent the Cholethiasis in subjects with Prader Willi Syndrome?
Stegmann, Jorgelina1; Quaglia, Federico C.A.1,2; Biasatti, Cintia1; Ceccomancini, Romina1; Paradiso,Alex D. 1
1

SPINE Foundation, Buenos Aires, Argentina; 2Psychiatry Department, Centro de Educación Médica e
Investigaciones Clínicas (CEMIC), Buenos Aires, Argentina.
Introduction: The prevalence of cholelithiasis in general population is approximately 15%. Some of themany clinical features and therapeutic targets of subjects with (Prader Willi Syndrome) PWS are risk
factors for the development of cholelithiasis in the general population including female gender, obesity,
sudden weight loss, diabetes mellitus and family history of gallstones. The authors don’t know otherstudies about cholelithiasis in people with PWS. The aim of this study is to identify risk factors andproportion of cholelithiasis in a sample of individuals with PWS. Materials and Methods:
Observational and descriptive study based on sample of subjects in treatment monitoring in the SPINEFoundation date January 2016 in Buenos Aires, Argentina. Clinical data were tabulated andpercentages and sample averages were obtained. Sudden drop in weight decline is defined as greaterthan or equal to 1.5 kg / week. Results: From a sample of 19 subjects with PWS, 36.84% (n=7)
presented cholelithiasis during follow-up treatment. Most individuals (85.71%, n=6) had cholelithiasis
at the beginning of the treatment and only one subject (8.33%) in its follow-up. Of the women in thesample (n=6), 50% had cholelithiasis (n=3); while the total number of men (n=13), only 30.76% (n=4)
of the men in this sample presented this digestive pathology. The average age of subjects with PWS
and cholelithiasis was 26.14 years (range 11-33 years) and an average of 23.42 years (range 11-35
years) subjects with PWS without cholelithiasis. All individuals with PWS with cholelithiasis wereobese (n = 7) in our sample. Three subjects (42.85%) with cholelithiasis as a risk factor had the sudden
drop in weight decline with a single case among subjects without cholelithiasis (8.33%). None of thosewith cholelithiasis had diabetes mellitus as a risk factor. While a smoker with PWS (5.26%) presented
cholelithiasis, two smokers with PWS didn't suffer cholelithiasis (10.53%). Four subjects with PWS
with cholelithiasis (21.05%) had a family history and only two people with PWS without cholelithiasis(10.53%) had family history of cholelithiasis. Our sample individuals who have not filed as diagnostic
malabsorption syndrome, or hepatic cirrhosis, or cystic fibrosis or pregnancy or oral contraceptive use
so that could not be valued as risk factors. Conclusions: Given the preliminary data of this reduced
sample, the proportion of people with PWS with cholelithiasis appears to be greater than the reference
values in the general population. The risk factors would be the same as for general population except
the female sex perhaps with a less impact on people with PWS. Future research could clarify theprevalence, risk factors and their role in caring for people with PWS.

Summary: People with PWS could have greater proportion of bladder stones and bile ducts than
general population. Given the potential clinical complications, this medical condition should be taken
into account in clinical routine of these people.

9th IPWSO Conference | P11

P12 - PRASOC project: Study of the cognitive capacities to process emotional and social
informations in the Prader-Willi syndrome
A.-M. Camblats1, J. Maire1, J. Chevalère1, S. Roux1, S. Mathey1, C. Bellamy2, M. Glattard2, M.
Tauber2, D. Thuilleaux3, V. Laurier3, F. Besnier2, & V. Postal1
1
Université de Bordeaux, Laboratoire de Psychologie, Santé & Qualité de Vie EA4139, Bordeaux,France ; 2Hôpital des Enfants, Toulouse, France ; 3AP-HP Hôpital Marin, Hendaye, France
Background
Prader-Willi syndrome (PWS) is a rare genetic syndrome characterized by several behavioral andcognitive disorders as hyperphagia, mild intellectual disability and a dysexecutive syndrome. Somestudies have showed a deficit to process emotional and social informations (Whittington & Holland,2011). The aim of this research is to determine if the abilities to process emotional faces and words andto infer mental state are impaired in the PWS and if these deficits are linked to the intellectual level ofthe PWS.
Methods and Results
Thirty one PW adults (M = 32.93 years), 25 adults with an intellectual disability without a PWS (M= 29.92 years) and 29 adults without intellectual disability (M = 27.41 years) participated to this study.
In the Experiment 1, participants performed a recognition task with emotional faces (fear, angry, joy,surprise, disgust, sadness or no emotion) and forms. A morphing procedure has modified the intensityof the expressed emotion (50% or 100%). In the Experiment 2, participants did an emotional Stroop
task with positive, negative or neutral words and a food Stroop task with control or food words (low ofhigh calories). In the Experiment 3, participants performed the TOM-15 to assess cognitive theory of
mind.
Results of the Experiment 1 demonstrated that the two groups with intellectual disabilities have
weaker performances than the control group but only for the face pictures, and revealed a specificdeficit for angry and surprise faces in the PWS. Moreover, groups with an intellectual disability had
more difficulty to recognize emotion at 50% rather than the control group. Results of Experiment 2
showed an emotional Stroop effect for negative words for the control and PW groups but not for groupwith an intellectual disability without PWS. A food Stroop effect was revealed only for participants
with a PWS, specifically for stimuli low in calories. Finally, results of Experiment 3 showed a general
impaired to the score at the TOM-15 for both groups with an intellectual disability.
Conclusions
Taken together, results of Experiments 1-2 not suggest an overall deficit to process emotional
stimuli in the PWS but a specific deficit which was not always linked with the intellectual disability.
Results of Experiment 3 showed difficulty to infer mental state to oneself or other people in the PSW,
this time associated with the intellectual disability. These results can be associated with behaviour
disorders observed in the PWS as the temper tantrum or the food regulation deficit.
Summary
In three experiments, we have study the abilities to process emotional and social stimuli in the
PWS. People with a PWS not show an overall deficit. The PWS corresponds to a complex cognitive
pattern. Some capacities seem to be comparable to those without intellectual disability but others
similar to the group with an intellectual disability and finally some capacities seem to be specific to thePWS.

P12 | 9th IPWSO ConferenceP13 - French experience of assessment of hyperphagia in PWS patients
G. Diene, C. Molinas, S. Faye, I. Kieffer, M. Valette, M. Glattard, B. Jouret, S. Çabal-Berthoumieu, C.
Noual, M. Tauber.
Centre de Référence pour le Syndrome de Prader-Willi; Hôpital des Enfants, 330 avenue de Grande Bretagne,
TSA70034, 31059 Toulouse cedex 9, France

Background: In 2007 Dykens et al. published a new questionnaire developed for PWS patientsassessing hyperphagia. This questionnaire has never been explored in the French PWS population. We
used this in our PWS population.
Methods and results:
We analysed all the questionnaires filled during a routine visit of children and adults with PWS on the
French reference Centre from 2010 to 2015. Several variables (age, sex, genetic diagnosis, body massindex (BMI)) were recorded for each patient. Questionnaires with missing items were excluded (n=9).
The whole population comprises 102 patients with 44% of male; the median age is 11.5 years ranging
from 4 to 45 years. Eighty one patients were aged less than 20 years. The genetic subtype was deletionin 63.7% (9.8% type 1, 38.2% type2) and disomy in 34.3%, imprinting defect in 1% and others in 1%.
According to International Obesity Task Force BMI charts, 37.3% patients had normal BMI, 23.5%
were overweight, 23.5% were obese (BMI > IOTF 30) and 15.7% were excessive obese (BMI > IOTF
35).
We analysed the 3 subscores of hyperphagia questionnaire, hyperphagic behaviour, hyperphagic driveand hyperphagic severity in the whole population and in 4 age classes: ≤4 and ≥10 years (N=48); ≤11and ≥19 years (N=33); ≤20 and ≥29 years (N=13) and ≥30 years (N=8). In the whole population, themedian hyperphagic behaviour subscore was 10 ranging from 5 to 23, the median hyperphagic drive
subscore was 10 ranging from 4 to 20 and the median hyperphagic severity subscore was 4 ranging
from 2 to 9. The 3 subscores significantly increased with BMI with significantly higher scores in obese
and excessively obese patients compared to those with normal BMI. The hyperphagic drive andseverity subscores were significantly higher in the group of oldest patients (>30 years) than in theyoungest patients (≤4 and ≥10 years) but no other significant difference was observed regarding age.
We did not observe difference according to sex in the whole population and in the different age classes.
There was no difference between the patients with deletion and the patients with non-deletion. Among
patients with deletion, patients with type 2 deletion have more severe subscores than patients with type
1 deletion (10 vs. 8.8 for hyperphagic behaviour, 10 vs. 7.5 for hyperphagic drive and 4 vs. 3 for
hyperphagic severity, p<0.05) although there is no significant difference in BMI repartition.
Conclusions: The hyperphagia questionnaire is an easy and interesting tool to characterise feeding
behaviour in patients with PWS sensitive enough to identify differences in some genotype subtypes.
Summary: We assessed hyperphagic behaviour in 102 French patients with PWS using Dykens
questionnaire. Scores were analysed according to sex, age, body mass index and genetic subtypes.

9th IPWSO Conference | P13

P14 - Weight Management for Youth with Prader-Willi Syndrome:
Delivery to Parents via Telemedicine
Melissa A. Kalarchian, PhD, Jennifer P. Elliott, PharmD, Khalid M. Kamal, M. Pharm., PhD,
Roxann Diez Gross, PhD, Heather Roach, MS, Gina Salvatori, RD, LDN, Gregory Cherpes, MD
Duquesne University and the Children’s Institute of Pittsburgh
Background. Although youth with Prader-Willi Syndrome (PWS) who receive a diet and activity
program in a tightly controlled inpatient hospitalization setting experience significant weight loss, they
are at risk for weight regain after they return home. However, interventions targeting weight
maintenance for youth with PWS in the family and home environment are nonexistent. An
interdisciplinary team of investigators from Duquesne University and the Children’s Institute of
Pittsburgh aims to address this tremendous unmet medical need among individuals with PWS.
Virtually all evidence-based approaches to treatment of childhood obesity are family-based.
Furthermore, there is support for working exclusively with the parent for child weight management.
This stands to reason as the home environment in general, as well as parent feeding in particular,
contribute to childhood obesity. Additionally, a growing body of data indicates that behavioral weight
management interventions can be successfully delivered via telemedicine. The goal of this pilot study
is to demonstrate that telemedicine may be a practical and relatively low-cost way to deliver a
behavioral intervention for child weight management directly to parents of youth with PWS in thehome setting.
Methods and Results. The team plans to pilot an evidence-based, behavioral weight management
intervention for delivery to parents of youth with PWS via telemedicine. Content is adapted to theunique needs of this patient population. Proposed treatment targets include 1) creating a healthier homeenvironment; 2) parenting and parent feeding; and 3) compliance with diet and activity. Theintervention consists of weekly contacts with parents over a three month period following childdischarge, as well as tracking of child body weight with a wireless weight transmitting scale provided
to the family. It could be delivered by providers interacting with youth and families in the inpatientmilieu, such as a registered dietitian, exercise physiologist, psychologist, pharmacist, or nurse. The
team has not yet evaluated the proposed intervention.
Conclusions. A pilot study would represent a critical first step toward a larger scale effort to evaluate
and disseminate an effective intervention to parents and youth with PWS. Through this poster
presentation, the team is seeking valuable input on the proposed intervention approach from patients,
providers, and policy makers.
Summary. An intervention delivered to parents at home via telemedicine has a strong potential
for preventing weight regain among youth with PWS following discharge from an inpatient
hospitalization. Moreover, creating a continuum of care that extends from the hospital setting to
the home environment may ultimately prove to be a cost-effective approach to increasing accessto specialized services at home and decreasing the need for inpatient hospitalization.

P14 | 9th IPWSO ConferenceP15 - PWS & Self-Determination
Helping Parents & Teachers to Enhance Child Resources to Grow in Autonomy
Irune Achutegui
San Raffaele Hospital, Milan, Italy

BACKGROUND: Adults beliefs, attitudes, feelings and expectations about autonomy, play animportant role in well-being and quality of the relationships of PWS people.
Questions to investigate:
What concept of autonomy have parents? Coincides with that of teachers?
What is the level of awareness about the strengths and the limitations caused by the disease?
Changes according to the age of the child?
In which areas are striving parents and teachers?
Signs for the future by parents and teachers.
Advice from experienced parents for parents with small children
METHODS AND RESULTS
Sample: 35 subjects (5 to 22 years) were evaluated through a specific Autonomy Questionnaire for
Parents & Teachers and reports drawn during discussion groups.
Research areas: self-care, food relationship, social inclusion, learning, homework (modified foryoungest in communication & language), move around the area (modified for youngest in motor skills),
managing money, experiences away from family (modified for youngest in Autonomy/separation fromadult).
Parents & teachers show different perceptions between the quantitative data and the description
examples of life situations: rather positive assessment, denying dangers, reflect optimistic attitudes as
opposed to limited autonomy in real situations.
CONCLUSIONS
The data underline the similarity in “parent-child” and “teacher-student” relationship, because it
implies dependence and responsibility, along an acceptance and balance between the difference needs(protection, exploration) of child. Adults beliefs, involvement and priorities, play a decisive role inautonomy and well being of the child: providing a mental representation of himself, of others, of theworld that will guide his behavior. The growth, also for caregivers, implies new knowledge, throughvarious types of support and guidance, relationships that increase confident or vulnerability, thatenhance trust or facilitate dependency.
There is a need for different levels of supervision by informed adults about PWS and aware of thespecificity of the subject. By discussion of everyday situations, the group allows adults to deal
realistically information about PWS: sharing not only limits and worries but also discoveries of positive
aspects, providing ad hoc information, signs and advice on individual subjects. Thus creating theconditions for the development of a network of support for autonomy from the school and the family.
SUMMARY
This study underlines the influence of the beliefs of parents & teachers about autonomy: convictions
are reflected on the perception of the syndrome, in the communication of the diagnosis and on
educational styles. The study underlines also the importance of the adults role in enhancing andsustaining child with PWS to grow in autonomy, generalizing learnings from rehabilitation therapies inevery day life.
9th IPWSO Conference | P15

P16 - First results of the larger study on the evaluation of the impact of cognitive and executive
abilities on socialization difficulties in childhood with PWS
Bellamy C1., Glattard M1., Camblats A2., Chevalère J2., Diene G1., Cabal-berthoumieu S1., Tricot J3.,
Thuilleaux D3, Besnier F4., Chirossel C4, Tauber M1., Postal.V.2
1
Reference Center for Prader-Willi Syndrome; 2Psychology Laboratory, Bordeaux University; 3Marine
Hospital of Hendaye; 4Association Prader-Willi France
Background
Prader Willi Syndrome (PWS) is a very complex disorder. Patients and families deal with strong
difficulties in daily life due to feeding and emotional disorder, with cognitive impairment. PW persons
have been recently shown to display executive deficits which may explain behaviors like temper burst,
repetitive behaviors and cognitive rigidity. We present here a study focused on the impact of emotionaland food items on the executive processes by administrated a variant of the Stroop task, an emotionalrecognition task and a task of the theory of mind on children with PWS.
Methods and Results
Twenty children with PWS aged 6 to 17, mean age 11.0 (s.d.2.9) years and mean IQ 117.74 (s.d.10.9).
Their performances were compared with a control group of 17 age matched children, mean age 11.0
(s.d.3.2) years with a mean IQ 67.30 (s.d.19.1). Three neuropsychological tests were used: a task offalse beliefs to assess the theory of mind, a task for emotion faces recognition, and the emotional andfood Stroop test to assess the treatment of emotional items.
On the Stroop, PWS children have a response time more important than the control group, as well on
emotional Stroop (p=.007) than food Stroop (p<.001). They are significantly slower on the healthy andcaloric food images than on the neutral ones without food. Interestingly we didn’t find an effect of thefood images on the response time in the control group. In the emotional Stroop, the control group issignificantly slower both on positive and negative images than neutral ones, while in PWS group, theresponse time on the positive images is faster than on the negative ones. On the facial emotion
recognition task as a whole, children with PWS made significantly more mistakes than the controls(p<.001). Nevertheless children with PWS tend to recognize anger and joy on the faces as well as
controls. For other emotions, children with PWS failed more than controls. On the theory of mind test,
the control group performs better than PWS group (p<.001), both in false belief and understanding of
the story.
Conclusions
On the 3 tasks, the PWS group display lower competences than the control group. They are sensitive toany food items (healthy and caloric) which slows their reaction time. They are more sensitive topositive than negative images. They recognize the basics emotions (joy and anger) like control groupwhile they fail more on the complex emotions. The theory of mind is largely deficient compared tocontrol group.
SummaryThis abstract presents the preliminary results of the PRASOC project on neuropsychological tasks with
PWS children to assess some executive abilities in link with the emotional component. This study
permits to apprehend the developmental pattern of cognitive capacities by comparing the results with apopulation without PWS.

P16 | 9th IPWSO ConferenceP17 - Manifestation of behavioral problems and BMI scores in persons with PWS by age groups,
and daily living condition of adults with PWS in Japan
Yoshiro KATO a, Koji MINOSAKI b, Junko TANAKA-MATSUMI c
Kansai University of Welfare Sciences a, Surugadai University b, Kwansei Gakuin University c

The aim of this study was to assess the severity of maladaptive behaviors of persons with PWS and therelation between behavioral problems and age group in Japan. In addition, BMI scores by age groupand daily living conditions in adulthood were investigated.
Questionnaires including the CBCL (Child Behavior Check List, Achenbach, 1991) were mailed toparents of persons with PWS. A total of 296 persons (52% male, 48% female) with PWS, aged 1 to 44
years, were rated by their parents using the CBCL. We divided these 296 persons into 7 age groups.
The mean BMI scores increased markedly with age; group 1 (n = 19, aged 1-2) was 13.62, group 2 (n =43, 3-5) was 14.88, group 3 ( n =40, 6-9) was 16.61, group 4 ( n =54, 10-14) was 20.85, group 5 ( n=51, 15-19) was 25.45, group 6 (n =59, 20-29) was 34.55, and group 7 ( n =30, aged>30) was 37.87.
The total CBCL scores of the majority of children with PWS fell in the clinical range. Most of the
CBCL subscale scores and the percentage of persons with maladaptive behaviors tended to increase
with age. Delinquent and Aggressive behaviors were remarkable in two groups whose ages were 15-19
and in the 20s. However, mean scores on the CBCL Internalizing and Externalizing dimensions for the> 30 years group were both lower than those of the group in their 20s. On the CBCL Clinical scale forDelinqency, the >30 years group scored significantly lower than did the group in their 20s.
“Stealing outside” is the most serious problem especially for those with PWS. It is the most distressful
problem for families. It is a problem for parents as their grown-up children can no longer use the social
welfare transformation services to go to work or school in Japan. Parents, therefore, provide
transportation for their grown-up children in order to prevent them from stealing. For the future, weplan to gather further information as to how parents deal with these problems, and how police oradministration of justice deal with these matters in other countries. And the effective psychosocial
intervention plan is needed.
In addition, these problems reduce QOL of persons with PWS. The percentage of nonworking adults
with PWS was much higher than that of persons with intellectual disability. Approximately 90% of
adults with PWS live with their parents in Japan. The remaining 10% of adults with PWS live in
traditional style residential facilities for persons with intellectual disabilities. There are no group homes
specialized for persons with PWS in Japan.
Summary: Percentage of persons with PWS revealed maladaptive behaviors tended to increase by age
in Japan. Most of adults live with their parents and the percentage of them going to work is very low.

9th IPWSO Conference | P17

P18 - Cerebellar hyperperfusion in PWS patients: the link for satiety?
C. Mantoulan1,2,3, PhD, P. Payoux1,2, 4, MD, K. Boulanouar2, G. Diene3, MD, M. Glattard3,5, PhD, B.
Rogé5, PhD, C. Molinas3, 6, 7, A. Sevely4, MD, P. Celsis1,2, 8, PhD, M. Tauber3,6, 7, MD
1

INSERM; Imagerie cérébrale et handicaps neurologiques UMR 825; F-31059 Toulouse, Cedex 9, France ; 2
Université de Toulouse; UPS; Imagerie cérébrale et handicaps neurologiques UMR 825; CHU Purpan, Place du
Dr Baylac, F-31059 Toulouse Cedex 9, France ; 3 Centre de référence du syndrome de Prader-Willi, Hôpital desEnfants, F-31059 Toulouse, Cedex 9, France ; 4 Centre Hospitalier Universitaire de Toulouse; Pôle Imagerie;
CHU Purpan, Place du Dr Baylac, F-31059 Toulouse Cedex 9, France ; 5 Unité de Recherche Interdisciplinaire
Octogone EA4156, CERPP, Toulouse, France ; 6 INSERM ; Centre de Physiopathologie de Toulouse-Purpan,
U1043; F-31059 Toulouse, France ; 7 Université de Toulouse; UPS; Centre de Physiopathologie de ToulousePurpan, U1043, Place du Dr Baylac, F-31059 Toulouse, Cedex 9, France ; 8 Centre Hospitalier Universitaire deToulouse; Pôle Neurosciences; CHU Purpan, Place du Dr Baylac, F-31059 Toulouse Cedex 9, France

Background: Prader-Willi syndrome (PWS) is a rare, multisystem genetic disease leading to severe
disabilities such as morbid obesity and behavioral and socialization problems. Imaging studies haveshown structural and functional brain anomalies in these patients and we showed specific relative
hypoperfusion in anterior cingulum and temporal gyrus.
Methods and results: Our analysis was performed in nine patients with PWS (six males, three females;mean age 16.4 years) who underwent positron emission tomography (PET) scanning with H215O as
tracer to measure regional cerebral blood flow (rCBF). The images were compared with those fromnine controls (six males, three females; mean age 21.2 years). In the patients with PWS, morphologicalmagnetic resonance imaging (MRI) was also performed. WISC-III and CBCL evaluations were
performed to characterize cognition and social skills.
The PET scans revealed relatively increased resting perfusion in brain regions in patients with PWS
compared with controls principally in the cerebellum.
Conclusion: Our results demonstrate that complex networks impaired in PWS are involved in foodintake and satiety which are also implicated in emotion, anxiety, executive functions and sensorial
perceptions.
Summary: PWS is a rare genetic disease leading to morbid obesity. PET scanning have been done tocompare nine patients with PWS to nine controls. Increasing resting perfusion in the cerebellum,
involved in food intake and satiety, have been observed in patients with PWS.

P18 | 9th IPWSO ConferenceP19 - Psychosis in Prader-Willi syndrome
Lucie Aman1, Katherine Manning1, Anthony Holland1,2,3
1:University of Cambridge, UK; 2: CPFT, UK; 3: NIHR CLAHRC, UK
Background: People with the UPD and IC genetic sub-type of PWS are at very high risk for psychotic
illness (up to 60% in adults with UPD). This observation suggests that, rather than loss of paternal
expression at 15q11-13, it is increased gene dosage of paternally imprinted/maternal expressed genes
located on chromosome 15 that is associated with mental illness in PWS. However, at present themechanism(s) are not understood hindering the development of specific treatments.
Methods & Results: A systematic literature review has been conducted to investigate potential
mechanisms that could explain the high rate of psychosis in PWS. First, one of the strongest leads is thepaternally imprinted gene UBE3A (15q11.2). An antisense transcript (AST) is produced, with apromotor located in the PWS imprinting centre, and binds to the UBE3A gene on the paternal
chromosome, inhibiting its transcription. Thus, people with mUPD would not produce this AST, and its
transcription would be altered in IC, resulting in both cases in increased dosage of the UBE3A geneproduct (an ubiquitin ligase protein); E6-AP, which is involved in GABA receptor recycling; NMDA
receptor regulation; and arachidonic acid inflammatory pathway - all mechanisms that have been
implicated in the aetiology of psychotic illness. Secondly, multiple studies in schizophrenia havedemonstrated reduced expression of pre and post-synaptic markers of GABAergic neurotransmission
and consequently a disrupted excitatory/inhibitory balance (Glutamate/GABA). Interestingly, three
GABA receptor subunits are encoded at the PWS locus 15q12. Thirdly, alpha7 N-acetylcholine
receptor, located at chromosomal locus 15q13.3 seems to be associated with schizophrenia in a least
two ways: in acting on GABA metabolism and on inflammation through the cholinergic antiinflammatory pathway: Fourthly, the immune system has been shown to play a major role in the
aetiology of psychotic illness through the action on neuronal growth, connectivity and neurotransmitterbalance and also, in rare cases, autoantibody activity against NMDA, potassium channel and GABA
receptors. There have also been consistent reports of increased levels of pro-inflammatory cytokines
and microglia inflammation associated with schizophrenia, involving brain inflammatory processes in
psychosis. Lastly, cognitive profiles differ between Del and UPD, and similar cognitive and sensory
impairments have been reported in UPD, in schizophrenia and in subjects at risk of psychosis,
indicating that it is possible that this may be involved in the increased propensity of those with the UPD
subtype to psychotic illness.
Conclusions: we propose that a gene dosage effect results in the high propensity to develop psychosis
in UPD, but the brain mechanisms that are underpin this risk are unknown. Drawing from the PWS andgeneral psychosis literature, we have proposed specific mechanisms.
Summary: we outline potential pathways involved in the development of psychosis in PWS, that weargue are a consequence of an increased dosage of paternally imprinted/maternal expressed genes onchromosome. Identifying the underlying brain mechanism would inform treatment developments.

9th IPWSO Conference | P19

P20 - Relationship between electrodermal activity and behavioural responses to inhibition andworking memory updating tasks in Prader-Willi syndrome: A sub-section of the PRASOC
project.
J. Chevalère1, J. Jauregui2.3, P. Copet3, V. Laurier3, D. Thuilleaux3, A.M. Camblats1, C. Bellamy4, M.
Tauber4, & V. Postal1
1

Univ. Bordeaux, Laboratoire de Psychologie, 33000, Bordeaux, France, 2 Euskal Herriko
Unibertsitatea, Paseo de Arriola 2 – 20018, San Sebastián, Spain, 3 AP-HP Hôpital Marin, BP 40139 64700, Hendaye, France, 4 CHU Hôpital des Enfants, 31300, Toulouse, France.
Background Prader-Willi Syndrome (PWS) is characterized by cognitive, neurological andphysiological disorders. As a multi-level symptomatology disorder, one path towards understanding thelinks between endophenotypical levels is to consider the concomitance of psychological andphysiological factors. This study aimed at exploring the links between the activity of the sympathetic
nervous system with electrodermal activity (EDA) and behavioral responses to executive tasks in an
event-related experimental design.
Methods and Results The performance of 30 adults with PWS was compared to 30 aged-matchedhealthy participants on two computerized executive tasks assessing inhibition and working memory
updating. Behavioural and EDA data were recorded and both were related to specific stimulation
events in order to isolate their impact on psychological and physiological measures. Compared tocontrols, adults with PWS exhibited general delayed behavioral responses associated with a lower tonic
EDA component and surprisingly earlier and weaker skin conductance responses. Correlational
analyses revealed links between electrodermal and behavioural measures in the two groups. However,PWS participants showed a lower number of these links as compared to controls.
Conclusion These results show that abnormal EDA is associated with cognitive impairment in PWS.
Furthermore, results indicate that PWS group showed weaker psychophysiological associations when
eliciting executive functions and open up perspectives for further investigation of these associations inthis disorder.
Summary The present study investigated the relationship between electrodermal and behavioural
responses to executive tasks among adults with PWS. Results highlight abnormal electrodermal activity
associated with cognitive impairment in this syndrome and weaker psychophysiological associations ascompared to healthy age-matched individuals.

P20 | 9th IPWSO ConferenceP21 - Muscle development and function in a Magel2 mouse model of Prader-Willi syndrome
Rachelle Eggert1,2, Ain A. Kamaludin1 and Rachel Wevrick1
1.Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada. 2.Department of Biologicaland Environmental Sciences, Concordia University of Edmonton, AB, Canada

Background: Prader-Willi syndrome (PWS) is a multigene disorder commonly associated withhyperphagia and obesity. Children with PWS have increased fat mass and decreased lean mass before
the onset of hyperphagia and obesity. Severe hypotonia and reduced muscle strength are typicallypresent in PWS infants. Inactivating mutations in one PWS candidate gene, MAGEL2, cause a PraderWilli-like syndrome (Schaaf-Yang syndrome) with neonatal hypotonia and joint contractures,
highlighting the importance of loss of MAGEL2 in PWS phenotypes. The process of autophagy isessential in maintaining musculoskeletal homeostasis, and increased or decreased autophagy can leadto muscle atrophy. Autophagic markers such as ubiquitin (Ub), p62/SQSTM1 (p62) and microtubule
associated protein 1-light chain 3 (LC3) are hypothesized to be connected to the MAGE family ofproteins that includes MAGEL2, suggesting that loss of MAGEL2 could modulate autophagy inmuscle.
Methods and Results: Expression of Magel2 was detected in the murine nervous system and indeveloping muscle, connective tissue and bone. Adult mice lacking Magel2 had reduced muscle mass,
increased fat mass and decreased bone mass compared to wild-type mice. Immunohistochemistry(IHC), immunoblotting and real time RT-PCR (qRT-PCR) were used to determine whether loss ofMagel2 affects the accumulation of autophagic markers or expression of genes associated with muscle
atrophy, in both neonatal and adult mice. The p62 positive aggregates were increased in muscle from
Magel2 mice and atrophy genes were up-regulated.
Conclusions: Abnormal autophagic processes likely contribute to muscle atrophy in mice lacking
Magel2. Further studies are needed to determine how the inactivation of Magel2 causes muscle
phenotypes at a cellular level. Our mouse strain carrying loss of Magel2 provides a model for muscular
dysfunction in Prader-Willi syndrome.
Summary: One of the symptoms of PWS is poor muscle tone, which could be caused by disruption in
the autophagy process that regulates skeletal muscle. Autophagy is disrupted and atrophy is increasedin muscle from mice lacking Magel2, one of the PWS candidate genes. We propose a mechanism bywhich loss of MAGEL2 causes hypotonia in children with PWS.

9th IPWSO Conference | P21

P22 - Altered gaze behavior during face processing in patients with Prader-Willi syndrome
J. Debladis, K. Strelnikov, C Mantoulan, J Salles, D. Thuilleaux, V. Laurier, C. Molinas, M. Tauberand P. Barone
Centre de Référence du Syndrome de Prader-Willi, Hôpital des Enfants, Toulouse, INSERM, Centre dePhysiopathologie Toulouse-Purpan, Toulouse, Hôpital Marin d’Hendaye, Cerveau and Cognition,
CNRS Toulouse, France.
Background : A large body of neuropsychological studies present evidence that Prader-Willi syndrome(PWS) have deficit in social communication. The difficulties of PWS with relationships with others areprobably related to abnormal processing of human face. Mixed results have been reported on how PWS
integrate face information. During a Benton Face Recognition Task, some studies report a near-normal
performance level while others report an abnormal face recognition scores in agreement with previous
studies revealing an impairment of PWS to attribute emotional or mental states from human facial
expressions. In order to progress in our comprehension of social impairment in PWS we investigatedthe oculomotor behavior of PWS engaged in a face recognition task.
Methods: 28 patients were recruited from the national reference center for PWS to perform a facerecognition task based either on the identity or the emotion (happiness, sadness and fear) of children
faces presented on a computer screen. After the presentation of a sample face, the patients have toselect among two other faces, which picture is the same subject or which face contains the same
emotional expression. During the test gaze behavior was recorded using a classical eye-tracker device(Mirametrix, Tobii).
Results: Compared to a group of 14 typically developing (TD) subjects, PWS are about 2 times slower
to execute the task, reaching high performance levels which are nevertheless significantly lower than in
TD (83 vs 96% respectively). A fine analysis of gaze behavior (%fixation time, FT) revealed that PWS
tend to gaze predominantly the mouth of the sample face (50% FT) while TD fixate mainly the eyes
(50% FT). Similarly, when searching for the matching face, PWS fixate equally the eyes and themouth/nose regions (51 and 49% FT respectively) while TD subjects are predominantly on the eyes
(68% FT). Preliminary analysis revealed also different scanning strategy when exploring the 2 faces.
Conclusions. Our results confirm previous studies of a specific deficit of PWS in face discrimination inspite of the weak difficult of the task. Further, PWS show altered eye gaze pattern avoiding the eyeregion which content most of the social information embedded in a face. Such altered face gaze in PWS
participates probably to the social communication deficit characteristic of PWS.
Summary. In the present study we show clearly that PWS present an altered oculomotor exploration ofhuman faces that contribute to their deficit in face processing, including emotional recognition.

P22 | 9th IPWSO ConferenceP23 - Role of the Prader-Willi Syndrome protein MAGEL2 in intracellular pathways regulating
leptin receptor processing.
T. Methsala Wijesuriya1, K. Vanessa Carias1, Leentje De Ceuninck2, Jan Tavernier2 and Rachel
Wevrick1
1

Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada, 2 Department ofBiochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
Background: Children with Prader-Willi syndrome have neonatal feeding difficulties, developmental
delay and excessive appetite. Loss of MAGEL2 causes a neurodevelopmental disorder (Schaaf-Yang
syndrome) and may contribute to obesity in children with Prader-Willi Syndrome who lack MAGEL2
and other genes. MAGEL2 is essential in neurons that sense levels of the adipose tissue-derived
hormone leptin. The MAGEL2 protein is important for recycling or degradation of proteins in the brain
and interacts with and modifies the activity of E3 ubiquitin ligases. RNF41 is a E3 ubiquitin ligase thatassociates with a ubiquitin-specific protease (USP8). Together with USP8, RNF41 regulates therecycling of the leptin receptor by targeting it either for degradation or for recycling to the cell
membrane. We hypothesized that MAGEL2 normally regulates the interaction between RNF41 and
USP8, and that loss of this regulation could impair leptin response pathways in the brain in children
with PWS.
Methods: Human U2OS cells were transfected with recombinant constructs encoding epitope tagged
versions of MAGEL2 and wild type and mutant forms of RNF41. Immunofluorescence was used tovisualize the co-localization of different forms of RNF41 with MAGEL2 in intracellular compartments.
We expressed recombinant MAGEL2, RNF41 and USP8 in combinations in human U2OS cells andexamined the relative abundance of each protein in the presence or absence of the other components ofthe complex.
Results: Abundance of RNF41 was lower when MAGEL2 was co-expressed, and abundance ofMAGEL2 was lower when RNF41 was co-expressed. This suggests that MAGEL2 and RNF41
proteins destabilize each other inside the cell. Abundance of RNF- SQ (ligase defective mutant) was
higher, while abundance of RNF-AE (USP8 binding mutant) was lower when MAGEL2 was coexpressed. Preliminary results suggest that MAGEL2 modifies the ability of RNF41 to autoubiquitinate or to ubiquitinate MAGEL2. Expression of all three RNF41 forms was higher when cotransfected with USP8, but co-transfection with MAGEL2 reversed the stabilizing effect of USP8.
Conclusion: Our results suggest that MAGEL2 could modify the activity of the RNF41-USP8
ubiquitination complex in leptin sensing neurons, providing a possible mechanism for dysregulation of
leptin sensing in neurons in children with Prader-Willi syndrome.
Summary: This study will help to understand how MAGEL2 interacts with the network of genes andproteins that normally control body weight. We will investigate the mechanism by which loss of
MAGEL2 could increase appetite and obesity in PWS, and children with inactivating mutations in
MAGEL2 alone.

9th IPWSO Conference | P23

P24 - Elucidating the neurobehavioral phenotypes of Magel2-null mice
Michael D. Fountain,1,2,3, Huifang Tao2,3, Chun-An Chen2,3, Jiani Yin2,3, Christian P. Schaaf1,2,3
1Interdepartmental Program in Translational Biology and Molecular Medicine, 2Department of
Molecular and Human Genetics, Baylor College of Medicine; 3Jan and Dan Duncan NeurologicalResearch Institute, Texas Children’s Hospital
Background: Prader-Willi syndrome (PWS) is a neurodevelopmental disorder characterized by avariety of symptoms, including a complex behavioral profile with temper tantrums, stubbornness,
controlling and manipulative behavior, obsessive-compulsive characteristics, and difficulty withchanges in routine. A subset of individuals with PWS meet criteria for autism spectrum disorder(ASD), and the prevalence of ASD among molecularly confirmed cases of PWS with loss of thepaternal copy of chromosome 15q11-q13 has been estimated as 27%, well above the rate of 1% in thegeneral population. MAGEL2 is one of five protein-coding genes in the PWS-critical domain on
chromosome 15q11. Six individuals with truncating variants of MAGEL2 have been reported, all ofwhich carry a diagnosis of ASD based on DSM-IV/V criteria and clinical assessment by an expert
physician. Since this time, we have identified an additional 40 individuals including 3 families eachwith multiple affected individuals, expressing a wide spectrum of neurodevelopmental phenotypes,
including a characteristic behavioral profile including impulsiveness, compulsiveness, manipulation,and stubbornness, and ASD. These findings highlight that ASD is a common phenotype amongindividuals with loss-of-function MAGEL2 mutations.
Methods and Results: Magel2-null mice (C57BL/6-Magel2tm1Stw/J) have been developed. They harbora maternally inherited imprinted wildtype allele and a paternally inherited Magel2-lacZ knock-in allele
that abolishes endogenous Magel2 gene function. These Magel2 null mice were found to exhibit
neonatal growth retardation, excessive weight gain after weaning, and increased adiposity with alteredmetabolism in adulthood, thereby recapitulating some of the core features of the PWS phenotype. The
same mice have reduced fertility in both males and females through extended breeding intervals andearly reproductive decline and termination. We performed a battery of behavioral assays on 20 maleand 20 female Magel2-null mice and their wildtype littermate counterparts.
Conclusions: Our studies suggest an altered social phenotype for mice with Magel2 mutations, inparticular a deficit in appreciation of social novelty. Patients diagnosed with PWS have been described
as being able to engage in social interactions and making friends, however, there are noted deficits inthe amount of time spent with friends and interpersonal communication, which may have somesimilarity to what we see in this mouse model.
Summary: The investigation of autistic behaviors caused by MAGEL2 loss-of-function may help us
understand a subset of behavioral phenotypes seen in PWS in general.

P24 | 9th IPWSO ConferenceP25 - Interactions between the Prader-Willi syndrome candidate protein MAGEL2 and neuronalproteins
Matthea Sanderson, Herman Cortes, and Rachel Wevrick
Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada
Background: Inactivating mutations in the MAGEL2 gene cause a neurodevelopmental disorder that includes
intellectual disability and autism spectrum disorder (Schaaf-Yang syndrome). MAGEL2 is one of the genes
inactivated in Prader-Willi syndrome, which shares many clinical findings with Schaaf-Yang syndrome. Loss ofMagel2 in mice affects brain development and function, disrupts circadian cycles and causes other phenotypes
that recapitulate symptoms of PWS. Mice lacking Magel2 have decreased brain volume in certain areas as well
as altered brain chemistry. However, little is known about the role MAGEL2 plays in brain function anddevelopment. Identifying the proteins that interact with MAGEL2 in neuronal cells will allow us to connect theunderlying molecular processes that MAGEL2 is involved in with neurodevelopmental deficiencies in PraderWilli syndrome and associated disorders.
Methods and Results: A cell line derived from neurons in the mouse hypothalamus (GT1-7) and a humanosteosarcoma cell line (U2OS) both endogenously express the Magel2/MAGEL2 gene. Recombinant epitopetagged MAGEL2 can be expressed in these cell lines and used to identify novel interactions. Complexes
containing MAGEL2 and associated proteins are purified biochemically to identify the interacting proteins. The
effects of over-expression of MAGEL2 or loss of expression of MAGEL2 on levels of these interacting proteins
will be examined.
Conclusions: These studies will provide additional insight into the cellular role of MAGEL2, and how
MAGEL2 participates in normal brain development and function.
Summary: MAGEL2 is one of the genes that is inactivated in Prader-Willi syndrome. Loss of MAGEL2
contributes to autism spectrum disorder in children with Prader-Willi or Schaaf-Yang syndrome. Through ourstudies of the MAGEL2 protein network, we will better understand why brain cells need MAGEL2 for theirfunction.

9th IPWSO Conference | P25

P26 - The Impact of Hyperphagia and Food Restriction on Siblings of Individuals with PraderWilli Syndrome
Elana Wishnefsky1, Anne Matthews1, Shawn McCandless1,2, Michelle Merrill2, Aaron Goldenberg3
1

Department of Genetics and Genome Sciences, School of Medicine, Case Western Reserve
University, Cleveland, OH
2
Center for Human Genetics, University Hospitals Case Medical Center, Cleveland, OH
3
Department of Bioethics, Case Western School of Medicine, Cleveland, OH
Background Having an individual in a family with PWS impacts the entire family system. The
behavioral phenotype and hyperphagia are usually the most difficult and stressful aspects of thedisorder to manage. Siblings are often highly involved in almost all aspects of care for theirbrother/sister with PWS and are immersed in the environment; thus it is important to understand theirperspectives on an in-depth basis of how this has impacted their eating patterns, their feelings towards
themselves and their families, and outlook towards their own futures.
Methods and Results Using a qualitative approach and a constant comparative thematic analysis,
twenty-four semi-structured telephone interviews were conducted with siblings over the age of 18 ofindividuals with PWS. Five major themes emerged including: “Environmental and dietary restrictions”;“Positive/Negative Feelings”; “Comfort with friendships”; “Supportive relationships”; “Sense of
responsibility.”
Conclusions Feelings of ambivalence towards their home environment as well as a sense of
normalization towards the behaviors of their sibling with PWS was a common experience exemplified
by participants. Stress surrounding strict eating regimens resulted in siblings having both positive andnegative eating habits. Participants also noted that the accessibility and utilization of support groups
was reduced. Moreover, participants identified that there is a present and/or future perception of
responsibility to care for their brother/sister with PWS. Next steps include determining when siblings
would best benefit from support along with enabling them to feel more adequate in the caregiving role.
Additionally, allowing typically developing children more time with their families may reduce negative
feelings towards their sibling with PWS.
Summary Siblings of individuals with PWS are greatly affected by being present in the environment
with their brother/sister and are largely involved in their care. The need for more support and early
professional involvement for siblings was a major finding of this study. Providing siblings with moreaccessible resources may allow for less negative experiences and more positive outcomes.

P26 | 9th IPWSO ConferenceP27 - The role of MAGEL2, a protein implicated in Prader-Willi syndrome, in the regulation of
RING-zinc finger-type E3 ubiquitin ligases
Vanessa Carias and Rachel Wevrick
Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada
Background. Prader-Willi syndrome (PWS) is a genetic disorder of the nervous and endocrine systems
characterized by developmental disabilities, obesity, excessive daytime sleepiness and night-time
wakening, and autism spectrum disorder. One of the genes inactivated in PWS is MAGEL2, andmutations in MAGEL2 alone cause the neurodevelopmental disorder Schaaf-Yang syndrome. The exact
cellular role of MAGEL2 remains to be elucidated. MAGE proteins interact with RING-zinc fingertype E3 ubiquitin ligases and enhance their activity. E3 ubiquitin ligases participate in protein
ubiquitylation, a cellular process in which substrate proteins are recognized, ubiquitylated, and targeted
for proteosomal degradation. Protein ubiquitylation is implicated in the regulation of diverse processes
including cell cycle, intracellular signaling, and transcription. TRIM32 is an E3 ligase that may interact
with MAGEL2 and has been implicated in other disorders such as Bardet-Biedl intellectual
disability/obesity syndrome and Limb-girdle muscular dystrophy type 2H, which overlap clinicallywith findings in PWS.
Methods and Results. To determine if MAGEL2 affects the E3 ligase TRIM32, constructs encoding the
wildtype and mutant forms were co-transfected in U2OS cells and analysed by immunoblotting.
MAGEL2 affects the abundance of TRIM32 in U2OS cells, with increased TRIM32 levels on cotransfection with MAGEL2. MAGEL2 also affects the abundance of mutant TRIM32, different fromthe effect of MAGEL2 on the wildtype TRIM32. By immunofluorescence analysis, we found thatMAGEL2 co-localizes with TRIM32 in the perinuclear region. Additional co-localization experiments
will be performed with mutant forms of TRIM32. We will investigate whether these proteins directlyinteract. Finally, we will determine if MAGEL2 affects the regulation of TRIM32 and theubiquitination levels of its substrates.
Conclusions. MAGEL2 may interact with TRIM32 and could affect its function in protein
ubiquitylation. The results from this project will elucidate the role of protein ubiquitylation in cellular
processes that can contribute to PWS symptoms. We will further understand how loss of MAGEL2 inchildren with Schaaf-Yang syndrome or PWS contributes to these complex disorders.
Summary. My project will investigate the role that MAGEL2, a protein implicated in PWS, has within
the cell. Understanding the function of MAGEL2 will shed light on how the loss of MAGEL2
contributes to neurodevelopmental disorders including PWS.

9th IPWSO Conference | P27

P28 - Characteristics of change triggered temper outbursts in children with PWS and ASD and
how these may impact on the efficacy of behavioural intervention strategies
Kate Anne Woodcock1, Clare McGeady1, Glenda Preston1, Áine Fitzpatrick1, Nigel Robb1, Katerina
Dounavi2 & Leah Bull3
1. School of Psychology, Queen’s University Belfast; 2. School of Education, Queen’s University
Belfast; 3. The Meadow Centre, Solihull, Birmingham
Background
Temper outbursts are prevalent in individuals with PWS and are often triggered by unexpected changes
to routines or plans. However, such outbursts are also common in individuals with several otherneurodevelopmental disorders, including those with a diagnosis of autism spectrum disorder (ASD).
We compared the profile of temper outbursts in children with PWS to that in children with ASD. We
examined whether differences in the temper outburst profile predicted differences in the outcomes of
two caregiver led intervention strategies aiming to reduce change triggered outbursts.
Methods and results
Thirteen 7-15 year olds with PWS – taking part in a larger study involving 60 children evidencing
temper outbursts following changes – were individually matched for age to children with ASD (meanages: 10.70; 10.76 yrs). Caregivers participated in a structured/semi-structured interview on children's
outbursts; completed a web-based outburst diary over a 6 month baseline; and are currently using eithera change signalling intervention to reliably warn children of forthcoming changes; or a planning aheadintervention to reduce children's exposure to unexpected changes.
As reported at interview, on average, children with PWS showed more frequent temper outbursts thanthose with ASD (closer to daily vs. weekly). For seven children with PWS and six with ASD, 60% ormore of their temper outbursts were reported to be triggered by changes. Whilst outbursts had similar
durations when triggered by changes or by other events in children with PWS; change triggered
outbursts in children with ASD were generally shorter. The most commonly reported outburst
components in children with PWS included indicators of heightened emotional arousal but this was not
the case for children with ASD. Data on behavioural change associated with each of the intervention
strategies will be discussed.
Conclusions
Change triggered temper outbursts can be a problem for children PWS and ASD, however subtle
differences appear to exist in the profile of these outbursts. Some of these differences may be relevant
for the expected efficacy of different behavioural intervention strategies that target outbursts.
Summary
Temper outbursts (tantrums) were compared in children with PWS or autism spectrum disorder before
and during use of one of two helping strategies. Helping strategies were led by caregivers and aimed toreduce outbursts that follow changes to routines or plans by making such changes more predictable, orby reducing the quantity of changes. Characteristics of outbursts may be important to help us predict
which helping strategies may be most effective.

P28 | 9th IPWSO ConferenceP29 - Beloranib Improves Hyperphagia-Related Behavior: Results from a Phase 3, Randomized,
Placebo-Controlled Clinical Trial of Beloranib in Patients with Prader-Willi Syndrome
Elizabeth Roof1, Jaret Malloy2, Dongliang Zhuang2, Nerissa Kreher2, Elizabeth M Dykens1
1

Vanderbilt University, Nashville, TN, 2 Zafgen, Inc., Boston, MA

Background: Prader-Willi syndrome (PWS) is the leading genetic cause of life-threatening obesity.
The insatiable hunger characteristic of PWS negatively impacts quality of life for patients and theircaregivers and can cause choking, stomach rupture, gastric necrosis, and other severe complications.
Beloranib inhibits MetAp2, an enzyme that modulates key cellular processes that control metabolism,lipid synthesis, and fat storage, and was recently shown to reduce body weight and hyperphagia in astudy in 17 patients with PWS.
Methods and Results: The effect of beloranib on hyperphagia-related behavior was investigated in
bestPWS, a 26-week, Phase 3, randomized, placebo-controlled clinical trial of biweekly beloranib inpatients with PWS and total score of ≥13 on the PWS-specific Hyperphagia Questionnaire for Clinical
Trials (HQ-CT), a retrospective 9-item questionnaire, each item scored 0-4 (total score 0-36), reductionin score indicates improvement. Baseline characteristics: (mean±SD) 20±6 y, BMI 40.0±10.1 kg/m2,
and HQ-CT total score 16.9±6.6. After 26 weeks, the placebo-adjusted reduction in HQ-CT total score
was -6.3±1.7 and -7.0±1.7 for 1.8 and 2.4 mg beloranib (both p<0.001). Beloranib-treated patients had
improvements vs placebo in all 9 HQ-CT items. Both beloranib groups had significant reductions vsplacebo in HQ-CT total score at Week 4, the earliest point measured. There were more HQ-CT
responders (identified using the anchor-based threshold of ≥7.7 derived from the Caregiver Global
Impression of Change) in the 1.8 mg (36%; p<0.05) and 2.4 mg beloranib (51%; p<0.001) groups vsplacebo (12%). Larger proportions of beloranib- vs placebo-treated patients reached a threshold
reduction in HQ-CT total score of at least 20%, 30%, 40%, and 50%. The most common AEs were
injection site bruising, aggression, and hyperphagia; only injection site bruising was more frequent withbeloranib vs placebo. The incidence of serious AEs was low and similar across treatment groups. Six
beloranib-treated patients withdrew due to AEs during the randomized treatment period (4 psychiatricAEs, 1 injection site pain, 1 pulmonary embolism resulting in death).
Conclusions: Beloranib treatment resulted in statistically and clinically significant improvements
hyperphagia-related behavior in patients with PWS.
Summary: This clinical trial investigated the effect of beloranib on body weight and hyperphagia inpatients with PWS. Beloranib-treated patients had greater improvements in hyperphagia-related
behavior vs placebo as early as Week 4. AEs were generally consistent with the patient population andprior clinical trials.

9th IPWSO Conference | P29

P30 - Parental approaches regarding prenatal diagnosis and termination of pregnancy in Prader
Willi syndrome
Noa Even- Zohar, Talia Geva-Eldar, Yehuda Polak, Harry Hirsch, Itai Gross, Varda Gross-Tsur.
Multidisciplinary Prader-Willi Syndrome Clinic, Shaare Zedek Medical Center, Jerusalem, Israel
Background: The field of prenatal diagnosis has recently developed tremendously resulting in serious
questions and ethical dilemmas such as the option of termination of pregnancy (TOP) in cases withsevere outcome. The decisions concerning TOP and prenatal tests is influenced by factors such as:
religion, gestational age, socio-economic status and years of education.
Prader Willi Syndrome (PWS) is a complex neurogenetic syndrome with high morbidity and mortality
due to severe medical and behavioral problems along the life span. PWS was rarely diagnosed
prenatally, lately, we documented that PWS have a unique prenatal phenotype and when any
combination of SGA or asymmetric intra- uterine growth, polyhydramnios, and diminished fetal
movements is present there is an indication for prenatal methylation testing. In this study we tried toevaluate the attitudes of parents of individuals with PWS to prenatal diagnosis (PND) and TOP under
different circumstances.
Methods All consecutive parents of individuals with PWS who attended the National Israeli PWS
multidisciplinary clinic between March-September 2015 were interviewed, using a semi structured
questionnaire about their attitude towards PND and TOP. The interviews were done by a single
physician (VTG) who treats and follows all families.
Results: Eighty five parents were recruited, no one refused. 31F/26M (67%) were in favor of invasive
prenatal tests. The rest agreed to non- invasive tests only. None opposed all PND tests. 17F/21M (44%)
ware in favor of TOP, 17F/14M agreed to TOP under certain conditions (36.5%) and 8F/7M wereagainst TOP (17.6%). The parental attitude correlated with religion status: M (p<0.000, F p<0.025,
mothers years of education (p <0.001), mother's working status (p<0.001) and for the fathers- child'sage (p <0.008). Couples had similar attitude regarding PND and TOP. No correlations were found withgender, PWS genetic subtype, age of the parents at the birth of the child with PWS or at time ofinterview.
Conclusions: Most parents of individuals with PWS think that PND is needed before and during
pregnancy including invasive tests. Being secular or religious had the most influential effect on thedecision of TOP. Unexpectedly, age of the disabled child does not affect parental decision.
Summary: In families with a child with PWS all parents are in favor of PNT even if they are against
TOP. Religion is the most significant factor in the decision of TOP. When giving a prenatal
consultation physicians and other counselors should be attentive and empathic to the perspective offamilies and guide them according to their principles

P30 | 9th IPWSO ConferenceP31 - Correlation of Five Distinct Characteristics of Prader-Willi Syndrome: A Four Year Case
Study on a Daily (School Days) Basis.
Biliou Vasiliki¹, Christina Theodoropoulou, Efstratios Alexandrou².
¹National Association of Prader-Willi Syndrome Hellas, ²Proseggisi Early Intervention Center Athens, Greece

Objective: Persons with Prader-Willi Syndrome (PWS) manifest an abundance of physical andbehavioral characteristics of variable degree. The occurrence and severity of these characteristics canrarely be predicted undermining the persons’ independency. We closely monitor the prominent
symptoms of the case study and describe their possible interrelation/correlation. Moreover, weinvestigate the possible impact of the sex hormones. Our objective is to inspire new ways of observing
and therefore researching the symptomatology of PWS.
Methods: The index person is an 11’ year old girl diagnosed with PWS, m-UPD also presenting
Autistic Spectrum Disorder (ASD). The PWS profile of the index case, in short, includes hypotonia,
hypothyroidism, precocious puberty, lean body mass and IQ 58 (WISC-III).
We sorted out the more distinct symptoms of our index case based on frequency, functional impairment
and, not yet, apparent correlation between them. Attention deficit, aggressiveness, daily sleepiness,cuticle picking and food seeking were selected.
We then defined the time period during the day, for the symptoms to be monitored, based on stabilityof the time frame and the environment, as well as the longest possible daily length of observation along
one year period. School hours met all the previous criteria.
Subsequently, we created a detailed 0-10 measuring scale for each symptom. All data are collected by
the same psychologist on a daily basis.
Finally, we will implement sex hormones’ curves over the curves of the symptoms in order to clarify
their relation since there are several behavioral indications that a full circle of 28 days is implicated.
Results: The observation of this index case revealed a strong correlation between symptoms’ scale andlong, school holidays, both preceding and following them. There is an apparent escalation of most
symptoms as the school week progresses. All symptoms, except cuticle picking, slightly attenuate over
the years. A preliminary analysis of the data shows that aggressiveness is negatively related to attention
deficit, cuticle picking is positively correlated to attention deficit and food seeking to daily sleepiness.
Conclusions: A full report of index case findings will be available for the conference along with theresults of the sex hormones impact on the symptoms. However, the preliminary analysis indicates new,interesting interrelations between the specific symptoms and therefore we suggest a wide, similar
research.
Summary: The physical and behavioral characteristics of persons with PWS can rarely be predictedundermining their independency. A daily (school days), four year long documentation and analysis offive distinct characteristics -attention deficit, aggressiveness, daily sleepiness, cuticle picking and foodseeking- of an index case with PWS was set with the preliminary results to indicate new, interesting
interrelations between the specific symptoms. Final findings will be presented at the conference.

9th IPWSO Conference | P31

P32 - Determining the Mathematical Profile of a Child with Prader-Willi Syndrome andApplying the Constructivism Model as a Learning Tool
Chanioti Eleni
M.Sc., Special Education Teacher, Scientific Advisor to the National Association for Prader-Willi Syndrome
Hellas, Greece

Background: Review of literature on Prader-Willi Syndrome (PWS) shows intense research activity
concerning its medical dimension. However, few studies have been conducted in terms of thecognitive and pedagogical dimension of the syndrome, and even fewer studies on those individuals’
mathematical skills. The population used in the few studies conducted up to day has been adults andnot children. Failure in mathematical skills acquisition constitutes the most striking characteristic in
the cognitive profile of individuals with PWS, and especially of type m-UPD.
Objective: The current case study aims at: a) evaluating the mathematical profile of a child with PWS(m-UPD) from the 1st grade up to the 4th grade of primary school and b) investigating the extent towhich application of the constructivism model of learning is effective regarding acquisition ofmathematical skills and improvement of motivation toward mathematics.
Methods: The case study is an 11-year-old girl diagnosed with PWS, m-UPD, at one year of age andAutistic Spectrum Disorder (ASD) by the age of 4. Initially, information from WISC-III, fromdiagnostic interviews in Number Sense by Denvir & Bibby and from Mann-Suitter Developmental
Arithmetic Inventory in 1st grade of elementary school was used for determining the child’s profile inmathematics. Then, an individualized program of intervention was constructed and applied on thebasis of the principles of the constructivism model. In terms of investigating motivation, aquestionnaire was completed by the mother, the parallel support of the child and the special educationteacher, in the beginning and the end of the study period.
Results: Data processing from tests used shows that: a) the child’s profile in mathematics presented in
specific areas similarities to what has been mentioned in literature regarding adults with the syndrome,b) the constructivism model of learning improved the child’s performance although intelligencequotient decreased. Improvement refers to areas of mathematical readiness, number sense, place value,arithmetic calculations, problem solving and measurements (time, money, weight, length), and c) the
child’s motivation toward mathematics was positively differentiated.
Conclusions: The educational model of active learning positively influenced the research subject’s
performance in mathematics. The results are encouraging and could lead us in a change of perspective
toward children with PWS and mathematics. We suggest further research in the pedagogical sector.
Summary: Through a number of tests, the current study examines performance in mathematics of achild with PWS, m-UPD, during the 1st grade of elementary school. “Learning by doing” is selected as
method of treating difficulties in mathematics while in the 4th grade the child is reexamined. The
results of the method are encouraging in terms of child’s performance in and motivation towardmathematics.

P32 | 9th IPWSO ConferenceP33 - Abnormal body composition phenotype in children with Prader-Willi Syndrome.
Camila E. Orsso1,2, Michelle Mackenzie2, Carla M. M. Prado1, Angela Alberga3, Andrea M. Haqq2
1

Department of Agricultural, Food and Nutritional Science, University of Alberta, 2Department ofPediatrics, University of Alberta, 3Werklunf School of Education, University of Calgary.
Background: Prader-Willi Syndrome (PWS) is a genetic syndrome associated with unfavorable
alterations in body composition such as reduced lean mass and increased adipose tissue. Detailed
analysis of skeletal muscle mass and adipose tissue distribution (subcutaneous, visceral andintermuscular) in PWS children has not been conducted. The aim of this study was to describe skeletal
muscle mass and adipose tissue distribution in PWS children.
Methods and Results: Anthropometric measures and an abdominal T1-weighted magnetic resonanceimaging were performed in PWS and control group. Multiple images from the top of the liver to the topof femoral heads were analyzed using Slice-O-Matic. Subcutaneous adipose tissue (SAT) was
identified using the “watershed” tool. Visceral adipose tissue (VAT), intermuscular adipose tissue(IMAT), and skeletal muscle mass (SM) were identified using a threshold technique. IMAT was
manually identified. Volume (cm3) of each tissue was automatically computed, and then converted toliters. Total adipose tissue volume (TAT) was calculated as a sum of SAT+VAT+IMAT volumes.
Mann-Whitney test was used to describe between-group comparisons, and Spearman rank correlations
to measure associations between variables. All data is presented as medians. PWS group (N=16) andcontrols (N=17) had similar age (10.5; 12.8 years; p=0.127) and BMI z-scores (0.49; 0.22; p=0.382).
WC z-score was significantly higher in PWS (0.69) compared to control (-0.04) (p=0.028). No
significant differences were observed in SAT, VAT, IMAT and TAT volumes between PWS andcontrols. Skeletal muscle mass was significantly lower in PWS (1.53 liters) compared to controls (3.11
liters) (p=0.008), and remained different when corrected for height (m2) (p=0.023). In PWS, VAT/SAT
was significantly lower (0.37) compared to control (0.50) (p= 0.014), and was negatively correlatedwith WC z-score (-0.680; p=0.004). In contrast, TAT/SM was significantly higher (PWS=2.25;
Control=1.18; p=0.000) as well as IMAT/SM (PWS=0.16; Control= 0.08; p=0.000). A strong positive
correlation between TAT/SM and BMI z-score (0.656; p=0.006) was noted in PWS.
Conclusions: PWS children exhibited reduced SM compared to controls, but similar measures ofabdominal adipose tissue. The decreased ratio of VAT/SAT suggests a positive metabolic pattern ofadipose tissue distribution. However, the greater TAT/SM and IMAT/SM ratios in PWS illustrates thatskeletal muscle plays a driving role in their unique body composition phenotype; it might be associatedwith poor motor development and function.
Summary: This study describes skeletal muscle mass and fat distribution in PWS children. Results
show that PWS children have similar amounts of fat in the abdomen, but reduced quantity of skeletal
muscle mass compared to healthy children. These findings might explain their difficulties withcoordination, balance and posture.

9th IPWSO Conference | P33

P34 - Methylene tetrahydrofolate reductase (MTHFR) polymorphisms, genetic subtype,
psychiatric diagnosis and symptom severity in PWS adults residing in group homes
Nicolette Weisensel MD1, Marge Royle PhD2, Linda Gourash MD2 and Janice Forster MD2
1
Prader-Willi Homes of Oconomowoc and Marion University, WI; 2Pittsburgh Partnership, Pittsburgh,
PA
Background: PWS is associated with a high incidence of mood disorders that vary according to
genetic subtype, symptom severity, and age of onset. Risk for psychosis is increased in both genotypes.
In the general population, MTHFR polymorphisms are associated with psychiatric disorder(depression, schizophrenia, mood disorder with psychosis and rapid cycling) particularly when serum
levels of folate are low or homocysteine is high. In this study the prevalence of MTHFR
polymorphisms, and serum levels of homocysteine, folate and vitamin B12 were ascertained among
adults with PWS residing in a group home system where diet was strictly controlled. Results were thencorrelated with serum levels, PWS genetic subtype, psychiatric disorder and indicators of severity.
Methods: Adults with PWS residing at the Prader-Willi Homes of Oconomowoc (PWHO) received
psychiatric diagnoses based upon clinical evaluation and DSM IV TR criteria. Clinical severity wasdetermined by the most severe diagnosis, cumulative diagnostic complexity, number of medications
needed to stabilize, and number of incident reports in the preceding 6 months. MTHFR gene
polymorphisms (677CT, 1298AC), serum folate, homocysteine and vitamin B12 levels were obtained.
Genetic subtype of PWS was previously determined by MS-MLPA.
Results: There were 28 adults; 14 males and 14 females. Distribution of MTHFR alleles was notstatistically different from population norms. MTHFR polymorphisms, 677CT (7), 677TT (3), 1298AC(8), and 1298CC (4), were mutually independent, except in one case of compound heterozygosity.
Distribution of PWS genetic subtypes was not representative: DEL I (5), DEL II (6), mUPD segmental
isodisomy (6), mUPD heterodisomy (8), and IC DEL (3). PWS genetic subtype varied independently
from MTHFR polymorphisms, but there were some gene interactions with serum levels associated with
folate metabolism. No one was folate deficient, but differences among genetic subtypes was significant(p<0.029) with higher folate level in IC DEL. Serum homocysteine levels were not elevated but variedwith PWS genetic subtype (p<0.068) and were inversely proportional to serum vitamin B12 (p<0.023)
and folate levels. Serum vitamin B12 levels were elevated in 1/3 of the cohort among individuals with
677CT (UPD>DEL), 1298AC (UPD) and 1298CC (DEL). Individuals with 677CT or 677TT
polymorphisms had lower mean number of incident reports, especially in DEL condition. Conclusions:
In this case series, MTHFR polymorphisms among PWS adults did not relate to genetic subtype. Serumhomocysteine, vitamin B12 and folate levels did vary by genetic subtype but were not related to
psychiatric symptom severity. However, the presence of the 677T allele was associated the lowest
number of incident reports. The literature suggests that the T allele is related to increased sensitivity toa stressful environment. If an incident report can be interpreted as an indicator of the behavioral
response to the environment, then the T allele may confer a protective effect in the consistency andstability of the PWS milieu. Elevated serum vitamin B12 levels without exogenous supplementation
were seen in 1/3 of this cohort. Further exploration of the regulation of folate metabolism in PWS is
warranted.
Summary: In this cohort, the distribution of MTHFR polymorphisms varied independently of PWS
genetic subtype. There were some interesting gene interactions with products of folate metabolism. The
presence of the MTHFR 677T allele is a recognized risk factor for depression in a stressful context, but
it may offer a protective effect in a controlled environment like the PWS milieu. 	
  P34 | 9th IPWSO ConferenceP35 - Early Diagnosis of Prader-Willi syndrome delays onset of obesity
Virginia Kimonis, MD1,2, Roy Tamura3, June-Anne Gold, MD1,4, Abhilasha Surampalli1, Javeria
Manazir1, Jennifer L. Miller, MD5, Elizabeth Roof, MA6, Elisabeth Dykens, PhD6, Merlin G. Butler,
MD, PhD7,and Daniel J. Driscoll, MD, PhD5
1

Department of Pediatrics, University of California, Irvine, California; 2Children’s Hospital of Orange
County, Orange, CA; 3Health Informatics Institute, University of South Florida, Tampa, FL;
4
Department of Pediatrics, Loma Linda University Medical School, Loma Linda, California;
5
Department of Pediatrics, University of Florida, Gainesville, Florida; 6Vanderbilt Kennedy Center for
Research on Human Development, Vanderbilt University, Nashville, Tennessee; 7Departments of
Psychiatry & Behavioral Sciences and Pediatrics, University of Kansas Medical Center, Kansas City,
KansasIntroduction/Background: Prader-Willi syndrome (PWS), affecting 1/15,000 individuals, is a genetic
disease characterized by lack of expression of genes on the paternal chromosome 15q11-q13 region with
70 percent caused by paternal deletions, 28 percent due to uniparental maternal disomy and 2 percent
caused by an imprinting defect. Clinical features include neonatal hypotonia, poor suck, feeding
difficulty, failure to thrive, hypogonadism, characteristic dysmorphic features, mild intellectual
disability, growth hormone deficiency with short stature, small hands and feet, and later developmentof excessive hunger and obesity and distinctive behavioral characteristics with temper tantrums,
outbursts and self-injury. Growth hormone replacement has revolutionized the stature and bodycomposition in individuals with PWS who have started treatment early. Despite significant advances inthe diagnostic genetic testing in individuals with PWS, the mean age for diagnosis continues to lag
behind. We hypothesized that early diagnosis and treatment of PWS reduces the risk of obesity andassociated co-morbidities.
Methods and Results: The long term data accrued from 351 Prader Willi patients recruited for the 9year NIH funded RDCRN (Rare Diseases Clinical Research Network) natural history studies wasanalyzed for age of diagnosis versus obesity and co-morbidities. Because of large variability in age ofdiagnosis, the age of diagnosis was categorized into 3 categories (< 1 yr, ≥ 1 yr and < 3 yrs, and ≥ 3yrs). Three variables from the Natural History Form: Age child first became heavy according to yourphysician, Age first developed an increased appetite, and Age first started to seek food, were analyzed
by the Cox proportional hazards model. The earliest reported age for each of these variables was usedas the endpoint age for each variable. In addition to age of diagnosis (categorized), race (white vs nonwhite), gender, and PWS type were included as covariates in the Cox model.
The mean age for diagnosis was delayed in a large group of subjects with 84 (25%) diagnosed with
PWS ≥ 3 yrs, 41 (12%) between 1 and 3 yrs and 208 (62%) < 1 yr (range from 1 month to 47 yrs old).
Both the age of diagnosis (p<.001) and race (p=.018) were significant factors for the age when childfirst became heavy. The estimated median ages for when the child first became heavy was 10 years forage of diagnosis < 1 yr, 6 yrs for age of diagnosis between 1 – 3 yrs, and 4 yrs for age of diagnosis
greater than 3 yrs. Non-white individuals exhibited earlier age of first becoming heavy than whites.
Age of diagnosis was not related to Age of development of an increased appetite, and Age of firststarting to seek food,Conclusion: It is critical for PWS to be detected early in order to avoid costly invasive diagnostic workups and permit early dietary and growth hormone treatment to prevent obesity. We propose thatmolecular technology currently exists to perform newborn screening to detect patients early to prevent
obesity and associated co-morbidities.
Summary: Early diagnosis and treatment of PWS delays the onset of obesity but not the onset of
hyperphagia or food seeking.

9th IPWSO Conference | P35

P36 - An oligonucleotide changes alternative splicing of the serotonin receptor 2C, reduces foodintake in mice and could substitute SNORD115
Zhaiyi Zhang, Marina Falaleeva and Stefan Stamm
University of Kentucky, Lexington, KY, USA
Background
The Prader-Willi critical region contains five C/D box snoRNAs (SNORDs) (107, 109, 64, 115 and116) that are not expressed in PWS subjects. The 47 copies of SNORD115 are almost identical andpromote alternative exon inclusion of the serotonin receptor 2C pre-mRNA. The serotonin 2C receptor
regulates food uptake and its activity is controlled by alternative pre-mRNA splicing and editing. Lossof SNORD115 leads to alternative exon skipping, which is predicted to generate a truncated receptor
protein isoform. cDNAs encoding this truncated receptor are located inside the cell, not at the cell
membrane. They heterodimerize with the full-length serotonin 2C receptor.
Method and Results
We raised an antiserum specific for the truncated serotonin receptor 2C (RNA1) and showed that the
expected protein is expressed in mouse, rat and human. We developed an oligonucleotide that promotes
exon inclusion, which increases the ratio of full-length to truncated receptor protein isoform. The
oligonucleotide works in the low nanomolar concentration and its intronic binding site is unique in thehuman genome. Decreasing the amount of truncated receptor results in the accumulation of full-length,
constitutively active receptor at the cell surface, suggesting that the ratio of full-length and truncatedreceptor controls the surface localization of the full-length receptor. After injection into the thirdventricle of mice, the oligonucleotide accumulates in the arcuate nucleus, where it changes alternative
splicing of the serotonin 2C receptor leading to an increase of the full-length, non-edited receptor. This
increase of the constitutively active receptor results in an increase of pro-opiomelanocortin (POMC)
expression. Oligonucleotide injection reduced food intake in wild-type mice. This effect is most likely
due to an increase in alpha melanocortin that is generated from POMC, as the oligo affects ob/ob mice,but not melanocortin receptor 4 knock out mice. Unexpectedly, the oligonucleotide crossed the blood
brain barrier and its systemic delivery reduced food intake in wild-type mice.
Conclusions
The physiological effect of the oligonucleotide suggests that a truncated splice variant regulates theactivity of the serotonin 2C receptor, indicating that therapies aimed to change pre-mRNA processing
could be useful to treat the hyperphagia, characteristic for Prader-Willi syndrome.
Summary
The truncated serotonin receptor 2C isoform has an important biological function: It sequesters the fulllength receptor inside the cell, which switches off the serotonin signaling. Through heterodimerization,
it could affect other receptor systems as well. These properties could explain why the loss of
SNORD115 in PWS creates a syndrome, affecting multiple receptor systems. Loss of SNORD115 canbe substituted with an oligonucleotide.
Reference: Zhang, Z., Shen, M., Gresch, P., Ghamari-Langroudi, M., Rabchevsky, A.G., Emeson, R.B. andStamm, S. (2016) Oligonucleotide-induced alternative splicing of serotonin 2C receptor reduces food intake.
Embo Mol. Med., in press.
P36 | 9th IPWSO ConferenceP37 - Von Economo neurons (VENs) in post mortem brains in PWS: a preliminary report
Janice Forster MD1, Merina Varghese PhD2 and Patrick Hof MD2
1

Pittsburgh Partnership, Pittsburgh PA; 2Fishberg Department of Neuroscience, Icahn School of
Medicine at Mt Sinai, NY

Background: VENs are large spindle cell neurons located in layer V of the frontoinsular (FI) andanterior cingulate cortex (ACC) of human brain. VENs appear bilaterally in the 8th month of gestation
but proliferate selectively in the right hemisphere. The number of VENs at age 4 is comparable to adult
numbers. Their putative function is to relay fast information necessary to ascertain social salience, selfawareness, and physiological state. They may also maintain balance in the autonomic nervous systemthat is essential for homeostasis. Recently, the role of VENs and pyramidal neurons in psychiatricillness has been explored in conditions of autism, schizophrenia, bipolar disorder, and frontotemporaldementia (FTD). This preliminary report describes the number, location, and morphology of VENs in
ACC and insula of post mortem brains in PWS.
Methods: The NIH NeuroBioBank provided 20 post mortem brains with PWS. Clinical information on
11 cases included age, gender, genetics, BMI, medical history, psychiatric history, and neuropathology.
Areas of interest (ACC and FI) were dissected as a block from the right hemisphere of the brain. Eachtissue block was prepared, sectioned, stained and examined to clarify cytoarchitectural boundaries ofregions of interest. VENs were identified and their densities, location, morphology and spatial
orientation were documented.
Results: To date, 7 brains have been examined. Stereological analysis, immunohistochemical testing,clinical correlation and genetic studies have not been performed as yet. In the ACC the VENs are
numerous in the area around the genu of the corpus callosum. Some samples showed large pyramidalcells, which are indicative of the cingulate motor field, but they are positioned more posteriorly thantypical for the ACC. VEN density is typically distributed in a ventro-dorsal and antero-posterior
gradient. There were more VENs in the ACC than in the insula, comparable to what has been seen in
autism. The cells in the ACC appear to be normal in morphology and orientation. But in the insula, theVENs are not distributed properly in regard to their spatial orientation; some were actually oblique.
Pyramidal cells were also in disarray. Further, VENs were found in the mid and posterior insula, where
they are not usually encountered. The functional significance of VENs in the posterior insula is notknown, but it appears to be a finding unique to PWS.
Conclusions: In this preliminary overview of the ACC and insula in post mortem brains of PWS
persons, the apparent density, morphology and spatial orientation of VENs and pyramidal cells is
intact. In contrast to the ACC, the number, morphology, spatial orientation and distribution of VENs in
FI is abnormal, and more comparable to what has been reported in autism. The presence of VENs in theposterior insula is a finding unique to PWS. Because VENs probably differentiate from pyramidal cells,
their distribution and orientation may be affected by abnormalities in brain folding during development.
Abnormal insular closure has been reported in PWS.
Summary: This is the first examination of the ACC and FI in post mortem brains in PWS. These very
preliminary findings indicate that the number, morphology, spatial orientation and distribution of VENs
in insular cortex are abnormal. In the ACC, both VENs and pyramidal cells appear to be more typical,
but additional quantitative and stereologic assessment has yet to be performed.

9th IPWSO Conference | P37

P38 - Functional and therapeutical investigation of the oxytocin system in the Magel2-deficientmouse model.
Françoise Muscatelli1, Valery Matarazzo1, Fabienne Schaller1, Alessandra Bertoni1, Marie-Solenne
Felix1, Laura Caccialupi1, Claude Villard3, Amélie M Borie2, Michel G. Désarmenien2
1 : Institut de Neurobiologie de la Méditerranée – INSERM901, AMU, Campus de Luminy, Marseille, France;
2: Institute of Functional Genomics, CNRS, INSERM, Montpellier, France; 3: Protéomique et Innovation
Technologique, INSERM911, AMU, Faculté de la Timone, Marseille, France.

Background: Prader-Willi syndrome is a complex disorder including severe feeding disturbanceslearning disabilities, behavioral and social disturbances. PWS involves several contiguous genes,
including the MAGEL2 gene. Recently, pathogenic mutations of MAGEL2 have been reported inseveral patients causing autism and PWS-like phenotypes. These results underline the major role of
MAGEL2 in PWS.
Compelling evidence coming from humans and animal studies suggests that a deficit in theneuropeptide oxytocin (OT) plays a central role in the pathogenesis of PWS. OT, for its central role in
the regulation of social behavior, has been proposed as a treatment for several neuropsychiatricdisorders characterized by deficits in the social domain. Preliminary clinical trials have been
carried out in adult patients and the results are controversial. However, it is conceivable that atreatment with OT early in life, when the plastic capacity of the brain is at a maximum and the social
and behavioral dysfunctions are not consolidated, could produce longer-lasting effects. Thus, an early
OT administration could act as a true curative intervention by exploiting the immature state of OTsystem and the higher plastic capacity of the brain.
Results: We have created a mouse model deficient for Magel2. This mouse model presents a similar
PWS phenotype with a deficiency in early feeding (from birth) and later on, in adulthood, alterations insocial behavior and cognition. Restricted production of several bioactive neuropeptides including OT
was detected in the hypothalamus of the mutant newborns. In such mutants, a single subcutaneous
injection of OT after birth rescues the feeding onset and suckling phenotypes allowing all mutant pups
to survive. Our study indicates for the first time that Magel2 and the OT/OT- receptor system play apivotal role in feeding behaviour at birth. Because the phenotype of Magel2 deficient murine neonatesmimics the feeding deficiency observed in PW newborns, rescue of the murine phenotype by OT
injection opens a promising avenue for better therapeutic care of the PW syndrome at birth.
Importantly, we have also shown that a daily administration of OT during the first week after birthcures alterations in social behavior and cognition in the adult Magel2-deficient mice, revealing a longterm effect of this early OT acute treatment.
Conclusion: The Magel2-deficient mouse model is particularly pertinent for understanding themechanisms of rescue of OT and for optimizing OT-based therapeutic strategies for the early feeding
behavior, social and cognition alterations in PWS. Currently we are investigating those questions andwe will present our ongoing studies.
Summary
Of great relevance for PWS, our team found that a postnatal administration of OT restores a normal
suckling activity and cures alterations in social behavior and cognition in the Magel2-deficient mice,
making this model particularly pertinent for understanding the mechanisms of rescue of OT and for
optimizing OT-based therapeutic strategies for this neurodevelopmental disorder.

P38 | 9th IPWSO ConferenceP39 - An in vitro model of Prader-Willi Syndrome by generation of hypothalamic neurons andgenome editing of induced pluripotent stem cells.
Elodie Mathieux, Erin Banda, Chris Stoddard, Heather Glatt-Deeley, Maeva Langouet, Leann Crandall
and Marc Lalande.
Department of Genetics and Genome Sciences, Stem Cell Institute and Institute for Systems Genomics
University of Connecticut, Farmington, CT, USA.

Background
Prader-Willi syndrome (PWS) is a disorder of genomic imprinting that is caused by the absence of anormal paternal contribution to chromosome 15q11-q13. Most other cases of PWS result fromuniparental disomy of the maternal chromosome 15. Recently the PWS critical region (PWSCR) has
been narrowed to an ~91kb region encompassing several non-coding RNAs including a cluster of box
C/D snoRNAs (SNORD116). PWS is characterized by neonatal hypotonia and failure to thrive
followed by hyperphagia, obesity, short stature, dysregulated sleep, infertility and distinctive
behavioral problems. These clinical manifestations are consistent with dysfunction of the
hypothalamus, a ventral diencephalon structure implicated in the control of the endocrine system.
Methods and Results
In order to differentiate in hypothalamic neurons from several PWS-specific and normal control
induced pluripotent stem cells (iPSC) lines, we modified existing protocols involving activation of the
Sonic Hedgehog pathway for both monolayer and 3-dimensional spheroid neuronal differentiation. We
compared the ability of control and PWS-iPSC derived neurons to adopt hypothalamic cell fates by
assaying for gene and neuropeptide expression. We observed a marked increase in the gene expressionof NKX2.1, OTP, RAX and POMC for the hypothalamic enrichment relative to our standard protocol.
These findings suggest that our normal and PWS-specific iPSC lines can be differentiated intohypothalamic neurons, particularly, those of the arcuate nucleus (ARC) region.
In order to gain an understanding of how the loss of the SNORD116 cluster contributes to PWS
phenotypic abnormalities, we used CRISPR/Cas9 to engineer isogenic pairs of human hESCs thatdiffer exclusively at the SNORD116 cluster. We confirmed the loss of expression of the SNORD116
cluster in the isogenic deletion line by qRT-PCR and RNA fluorescence hybridization. We will
differentiate isogenic normal and SNORD116 deletion lines into hypothalamic neurons in order to
identify novel cellular and molecular targets of the SNORD116 regulation.
Conclusions
We have generated hypothalamic neurons from different PWS-specific iPSC lines to better model PWS
and elucidate a cellular phenotype of PWS and to define the critical role of the SNORD116 cluster.
Summary
Our goal is to produce improved stem cell models of PWS. To do this, we are generating hypothalamic
neurons and engineering a deletion of the SNORD116 cluster.

9th IPWSO Conference | P39

P40 - Truncating Mutations of MAGEL2, a Gene within the Prader-Willi Locus, Are Responsible
for Fetal Akinesia and Arthrogryposis
Dan Mejlachowicz1, Flora Nolent1, Jérome Maluenda1, Hanitra Ranjatoelina-Randrianaivo2,
Fabienne Giuliano3, Ivo Gut4, Damien Sternberg5, Annie Laquerrière6, and Judith Melki1
1- Unité Mixte de recherche-1169, Inserm and University of Paris-Saclay, Le Kremlin Bicêtre, France.
2- Medical Genetic Unit, South University Hospital, St Pierre-La Réunion, France. 3- Reference Centerof Developmental Anomalies and Malformations, University Hospital, Nice, France. 4- Centro
Nacional de Análisis Genómico, Barcelona, Spain. 5- Service de Biochimie Métabolique, Hôpitaux
Universitaires Pitié-Salpêtrière, Paris, France. 6- Pathology Laboratory, University of Rouen, France.
Background: Arthrogryposis multiplex congenita (AMC) is characterized by the presence of multiple
joint contractures resulting from reduced or absent fetal movement. The difficulty in establishing a
genetic diagnosis for non-syndromic AMC individuals is due to the high genetic heterogeneity and/or
to some not yet identified disease causing genes.
Methods and Results: Here, we report two unrelated families affected by lethal non syndromic
arthrogryposis. By genetic mapping and whole-exome sequencing in a multiplex family, aheterozygous truncating MAGEL2 mutation leading to frameshift and a premature stop codon(c.1996delC, p.Gln666Serfs*36) and inherited from the non-affected father was identified in theprobands. In another family, a distinct heterozygous truncating mutation leading to frameshift(c.2118delT, p.Leu708Trpfs*7) and occurring de novo on the paternal allele of MAGEL2 was identified
in the affected individual. In both families, RNA analysis identified the mutated paternal MAGEL2transcripts only in affected individuals. Exome sequencing targeted to AMC genes including MAGEL2
allowed identifying additional families.
Conclusions: MAGEL2 is one of the paternally expressed genes within the Prader-Willi syndrome(PWS) locus. PWS has been reported in fetuses with a phenotype similar to that reported here. In thesecases, paternal deletion or maternal uniparental disomy of 15q11 were identified suggesting that PWS
should be considered in fetuses with such phenotype. Here we report that truncating mutations in
MAGEL2 are also responsible for this condition. MAGEL2 mutations have been recently reported inaffected individuals with features resembling PWS and called Schaaf-Yang syndrome. These data
revealed that intragenic mutations of MAGEL2 result in a large clinical spectrum ranging from severe
fetal phenotype (our report) to syndromic intellectual disability or autism (Schaaf-Yang syndrome).
These data strongly support the view that MAGEL2 is a PWS-determining gene. In the absence ofpaternal deletion or maternal uniparental disomy of 15q11, search for intragenic mutations on thepaternal allele of MAGEL2 should be proposed in fetuses with reduced movements, polyhydramnios
and distal arthrogryposis, newborns with severe undiagnosed central hypotonia or in children when
PWS is suspected clinically.
Summary: MAGEL2 mutations have been recently reported in affected individuals with features
resembling PWS (Schaaf-Yang syndrome). Here we report that truncating mutations in MAGEL2 arealso responsible for fetal akinesia and arthrogryposis suggesting that MAGEL2 is a PWS-determininggene.

P40 | 9th IPWSO ConferenceP41 - Brain and Behaviour in PWS
Katherine Manning1, Roger Tait1, John Suckling1, Howard Ring1,2,3, Anthony Holland1,2,3
University of Cambridge, UK; CPFT, UK; NIHR CLAHRC, UK.
Background: The diverse characteristics of PWS, as well as previous research, suggest widespreadatypical brain development and functioning in PWS and aberrant activity across distributed neuralnetworks. It is likely that the difficulties with emotional regulation and behaviour may be associatedwith abnormalities in the limbic cortico-striatal-thalamic circuitry, implicated in emotional cognition,
regulation and lability. Moreover, many of these are areas which have been most consistently
implicated in the literature regarding neural structure and function in PWS.
Methods & results: 20 participants with PWS, aged between 19-28 years, completed measures ofcognition and behaviour, and underwent an MRI scan consisting of the following sequences:multiparameter mapping (MPM), resting state fMRI, and DTI. MRI data for comparison was available
for 40 typically-developing controls, matched 2-to-1 for age and gender. A VBM analysis of grey
matter morphology found a number of areas of increased volume in PWS, which were widespread
across frontal, parietal, cingulate and temporal areas, extending into the more superior and anterior
regions of the occipital lobe. Ventromedial and wider orbitofrontal areas showed decreased volume, as
did the right lateral PFC and areas of the bilateral medial temporal lobes, bilateral temporal poles, andposterior parietal into occipital cortex. Within the PWS group itself, greater severity of maladaptive
behaviours was associated with reduced volume in the left insula and bilateral cingulate. Data
concerning cortical thickness and resting state functional connectivity will also be presented.
Conclusions: Widespread morphological abnormalities of both increased and decreased volume were
found in those with PWS compared to a typically-developing control group in areas previously reported
to show atypical anatomy or function in PWS and related behaviours, although the direction of findings
has often been inconsistent. In particular, areas involved in the cortico-striatal-thalamic loops
implicated in emotional and behavioural regulation or prominent connections and input areas werehighlighted. Volume in the cingulate and insula cortices, in particular, were associated with severity ofmaladaptive behaviour in PWS, and are widely implicated in emotional processing and interoception
and within circuitry involved in emotional state regulation. The largely bilateral nature of themorphological differences indicates an early and systemic biological basis to developmental
abnormalities.
Summary: The array of difficulties experienced by people with PWS suggests widespread differencesin the way the brain develops. This study compared young adults with PWS with typically-developing
peers, finding differences across the brain suggestive of early biological alterations in development. We
propose that these structural differences and their interconnections underpin the behaviouralabnormalities of PWS.

9th IPWSO Conference | P41

P42 - The development of resistance to change in individuals with PWS
Kate Anne Woodcock & Elaine Laura Haig
School of Psychology, Queen’s University Belfast
Background
Many individuals with PWS demonstrate a strong resistance to change and unexpected changes are acommon trigger for temper outbursts. Experimental work by our group has provided some evidence
that increased exposure to certain routines without change may accentuate the difficulties experienced
following changes to those routines. Here, we aimed to examine the relationships between resistance tochange and varying levels of exposure to routines over the life course.
Methods and results
The caregivers of 10 individuals with PWS (5-23 years) participated in a structured/semi-structured
interview in which they used a five-point Likert-type scale to rate the level of routines and structure
individuals had been exposed to at different stages of their lives. Life stages were anchored to notable
events to facilitate recall (e.g. before primary school, during primary school). Caregivers also rated
individuals' current resistance to change and the developmental pattern of resistance to change at eachlife stage compared to others. Open ended questions on routines and resistance to change were
included. Interviews demonstrated acceptable inter-rater and inter-informant reliability. Descriptive,correlational and comparative analyses converged to suggest that increased exposure to rigid routines
during the primary school life phase may be associated with increased resistance to change later in life.
However, in individuals with already established resistance to change, structured routines wereassociated with less disruptive behaviour.
Conclusions
Practice with flexibility via less rigid routines may be particularly important during primary school
years, when children's cognitive control processes – including task switching, which has been linked to
one’s ability to cope with change – develop rapidly. Strategies that increase flexibility in routines
during the primary school years may reduce the development of subsequent resistance to change.
However, careful research is needed to understand how to increase flexibility in routines during earlylife without negatively impacting on children’s current behaviour and wellbeing.
Summary
Interviews with caregivers of people with PWS suggested that children who experience more rigid
routines during primary school years may go on to develop greater difficulty with change later in life.
However, structure and routine can be very helpful for people with PWS who already find change
difficult. It should be possible to develop early prevention strategies based on this information but more
careful research is needed to find a feasible approach.

P42 | 9th IPWSO ConferenceP43 - Oxytocin neurons promote arousal in a mouse model of PWS
Carrie E. Mahoney, PhD1, Valery Grinevich, MD, PhD2, and Thomas E. Scammell, MD1
1

Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115
Schaller Research Group on Neuropeptides at German Cancer Research Center (DKFZ) and Cell
Network Cluster of Excellence at the University of Heidelberg, Heidelberg 69120, Germany

2

Background. Daytime sleepiness, disrupted sleep, and cataplexy-like falling episodes are common in
Prader-Willi Syndrome (PWS). The cause of these symptoms is unknown, but it may involve reduced
orexin signaling. The orexin neuropeptides activate the oxytocin neurons, and oxytocin activates theorexin neurons. We hypothesize that this positive feedback loop normally plays an essential role inpromoting wakefulness and regulating sleep. Furthermore, patients with PWS have fewer oxytocin
neurons, and we predict that low oxytocin tone reduces orexin signaling, resulting in daytime
sleepiness, abnormal REM sleep, and cataplexy.
Methods and Results. Using optogenetics and EEG, EMG, and video recordings, we examined
sleep/wake behavior in wild type, orexin knockout, and MAGEL2 null mice, a model of PWS. We
selectively expressed channelrhodopsin in oxytocin neurons of the PVH and targeted optical fibers toilluminate the oxytocin fibers of the orexin field.
Conclusion. In all three lines of mice, activation of oxytocin nerve terminals wakes mice from sleep
and increases the amount of wake during the day.
Summary. These findings demonstrate that oxytocin can increase arousal, most likely by activating theorexin neurons. This suggests that therapies that enhance oxytocin signaling may help people with
PWS better maintain wakefulness throughout the day.
Support: Foundation for Prader-Willi Research	  9th IPWSO Conference | P43

P44 - Abnormal Videofluoroscopic Swallow Studies (VFSS) in Infants with Prader-Willi
Syndrome Indicate a High Rate of Silent Aspiration
Parisa Salehi, MD1, Maida Chen, MD2, Anita E. Beck, MD, PhD3, Amber McAfee, ARNP2, SooJeong Kim, MD4, Lisa Herzig, MD5, Anne Leavitt, MD5
1
Seattle Children’s Hospital, Division of Endocrine, University of Washington, Seattle, WA
2
Seattle Children's Hospital, Division of Pulmonary and Sleep Medicine, University of Washington,
Seattle, WA
3
Seattle Children's Hospital, Division of Genetic Medicine, University of Washington, Seattle, WA
4
Seattle Children's Hospital, Division of Psychiatry, University of Washington, Seattle, WA Divisionof Pulmonary and Sleep Medicine, University of Washington, Seattle, WA5	
  Seattle Children's Hospital, Division of Developmental Pediatrics, University of Washington, Seattle,
WA

Background: Prader-Willi Syndrome (PWS), due to loss of expression from genes within the PWS
imprinted region at chromosome 15q11.2-13, is characterized by hypotonia and feeding intolerance ininfancy with later development of hyperphagia and obesity. Growth hormone improves tone, bodycomposition, and height and can be started in infancy. Morbidity and mortality in PWS include thosesecondary to hyperphagia and respiratory illness as well as a 17% reported incidence of sudden death inchildhood. Choking is a known hazard with a 34% reported incidence. Despite well-described feeding
intolerance in infants with PWS, there are no published reports of formal swallow studies.	
   We
hypothesize that VFSS will diagnose pathology missed by clinical observation and may help determine
feeding safety in PWS infants.
Methods and Results: VFSS results of infants followed in the interdisciplinary SCH PWS clinic
between October 2014 - April 2016 were reviewed. The study was approved by the SCH IRB.
Six infants with genetically confirmed PWS underwent 10 VFSS (age: 3 weeks-15 months; gender:
male 4, female 2; subtypes: deletion 3, uniparental disomy 2, imprinting defect 1). One patient received
5 studies over 14 months. Of all the studies, 100% indicated oropharyngeal phase dysphagia withabnormal pharyngeal clearance in 80% (5 infants). 100% showed silent aspiration with thin liquids,
60% with thickened liquids, 20% with purees. 60% were done while the infant was on growth
hormone. Average age of growth hormone initiation was 2.5 months. The infant with multiple studies
showed improvement over time, but still had an abnormal VFSS at 15 months old.
Conclusion: VFSS showed oropharyngeal phase dysphagia and silent aspiration in all infants which
may have been undiagnosed with only clinical observation. Abnormalities were present despite early
initiation of growth hormone. Careful consideration should be made before starting oral feeds in infants
with PWS, and VFSS can be a useful clinical tool in this decision. Swallow dysfunction may be acontributor to morbidity in PWS. Further longitudinal studies are needed to characterize swallowing
function in PWS over time.
Summary: Infants with PWS who had VFSS done to evaluate swallowing function were found to havea high rate of abnormalities, including silent aspiration and poor clearance of food after swallow. These
characteristics can increase risk of choking as well as lung disease from aspiration and may have been
undiagnosed without the VFSS. It is important to consider these risks in evaluation of safety for oral
feeds in infants with PWS.
	  P44 | 9th IPWSO ConferenceP45 - Role of the Endocannabinoid System in Prader-Willi Syndrome
Ibrahim Knani1, Brian J. Earley2, Shahar Azar1, Saja Baraghithy1, Shiran Udi1, Anna Permyakova1,
Rivka Hadar1, Daniela P. Reyes-Capo3, Harry J Hirsch4, Talia Eldar-Geva5, Itai Gross6, Andrea M.
Haqq7, Joan C. Han3,8, Varda Gross-Tsur4, Rachel Wevrick9, Joseph Tam1
1

Obesity and Metabolism Laboratory, The Institute for Drug Research, School of Pharmacy, Faculty of
Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel; 2Laboratory of Physiologic
Studies, National Institute on Alcohol Abuse and Alcoholism; 3Unit on Metabolism and
Neuroendocrinology, National Institute of Child Health and Human Development, Bethesda, MD
20892; 4Neuropediatric Unit, Department of Pediatrics, 5Reproductive Endocrinology and Genetics
Unit, Department of Obstetrics and Gynecology, Shaare Zedek Medical Center, Jerusalem 91031,
Israel; 6Department of Pediatrics, Hadassah Hospital, Ein Kerem, Jerusalem, Israel; 7Department ofPediatrics, and 9Department of Medical Genetics, University of Alberta, Edmonton, AB Canada, T6G
2E1; 8Pediatric Obesity Program , University of Tennessee Health Science Center, Le BonheurChildren’s Hospital, Memphis, TN 38103
Background: Extreme obesity is a core phenotypic feature of Prader-Willi syndrome (PWS). Amongthe numerous metabolic regulators, the endocannabinoid (eCB) system is critically involved in thecontrol of feeding, body weight, and metabolism, and globally acting cannabinoid-1 receptor (CB1R)
blockade reverses obesity both in animals and humans. However, due to their neuropsychiatric side
effects, they are no longer considered as a valid treatment for obesity in humans.
Methods and Results: Using an established mouse model for obesity in PWS, Magel2-null mice, wemeasured the expression of CB1R as well as the endogenous levels of the main eCBs, anandamide(AEA) and 2-arachidonoylglycerol (2-AG). We then determined the anti-obesity efficacy of theperipherally restricted CB1R antagonist, JD5037, in obese female and male Magel2-null mice. To
assess the relevance of our findings to humans, we measured eCB levels in the serum of two cohorts ofindividuals with PWS and their age- and gender-matched healthy controls.
Increased both hypothalamic and peripheral (circulating and adipose) eCB tone were found in Magel2null mice. Daily oral treatment of obese Magel2-null mice and their controls with JD5037 (3 mg/kg/d
for 28 days) resulted in significant and comparable reductions in body weight, food intake,hyperglycemia, hyperinsulinemia, liver injury and dyslipidemia in both mutant and control mice.
Human patients with PWS from Israel and the North America showed increased levels of 2-AG, but
not AEA.
Conclusions: Dysregulation of the eCB/CB1R system may contribute to obesity in Magel2-null miceand humans with PWS. Our findings with JD5037 in Magel2-null mice may provide the rationale forclinical testing of peripherally restricted CB1R antagonists for the treatment of obesity in PWS, while
avoiding the risk of psychiatric side effects.
Summary: Using a pre-clinical animal model for PWS and human data, our results document for the
first time the contribution of the eCB system to the metabolic phenotype associated with PWS.

9th IPWSO Conference | P45

P46 - Discovery of Dysphagia in Children and Adults with Prader-Willi Syndrome
Roxann Diez Gross PhD, CCC-SLP1, Ronit G. Gisser, MSc, CCC-SLP1, Gregory L. Cherpes, MD1,
Katie Hartman, MA, CCC-SLP1, Rishi Maheshwary, MD2
1. The Children’s Institute of Pittsburgh, Pittsburgh, Pennsylvania, 2. West Penn Allegheny Health
System, Pittsburgh, Pennsylvania
Background: The need for the Heimlich maneuver, death from choking (defined as asphyxiation by afood bolus), and fatal pulmonary infections occur in a disproportionally high number of persons with
PWS. The widely-held belief is that eating behaviors and silent aspiration are primarily responsible forthese events; yet, dysphagia (swallowing impairment) can also cause choking and lung infection. To
date, no investigation had directly examined swallowing function in persons with PWS. Therefore, thepurpose of this research project was to determine if subclinical (without symptoms) dysphagia(swallowing impairments) and/or risk factors for aspiration/airway invasion are present in persons with
PWS. We also sought to determine how eating behaviors contribute to choking and aspiration risk.
Methods and Results: Simultaneous videofluoroscopy and nasal respiratory signals were used torecord swallowing function and breathing/swallowing coordination in 30 participants with PWS.
Subjects drank thin liquid and ate barium cookies under two randomized conditions: 1. Controlled(cues to swallow and standardized bolus sizes) 2. Spontaneous (no cues or control of rate of
consumption, and no bolus size control). The results showed that persons with PWS can have multiple,
sometimes severe, symptoms of dysphagia and important risk factors for aspiration. Overall, the cohort
showed disturbances in timing between the oral and pharyngeal phases, incomplete pharyngeal andesophageal clearance, and impaired coordination of swallowing with the respiratory cycle. None of theparticipants showed any sensory response to their dysphagia such as attempting to clear residue or
coughing, thus verifying the lack of overt symptoms. There were no statistically significant differences
between the two conditions; however, the spontaneous condition did not elicit rapid eating or largebolus sizes in the majority of the participants.
Conclusions: We conclude that choking events and some pulmonary infections in children and adults
with PWS may be related, in part, to the underlying asymptomatic dysphagia that our experiment
revealed. Based upon these findings, it is recommended that persons with PWS should receive
videofluoroscopic swallowing evaluations that include examination of the esophagus.
Summary: Persons with PWS tend to have a higher than typical rate of choking deaths and fatal lunginfections. We used x-rays to determine that swallowing impairments, such as food sticking in thethroat and esophagus and other risk factors for aspiration, can be present even though there are no
symptoms.

P46 | 9th IPWSO ConferenceLathamCenters

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