ISTH
The 2011 State of the Art Book

Natural history of Upshaw-Schulman syndrome
based on ADAMTS13 gene analysis in Japan

Y. FUJIMURA*, M. MATSUMOTO*, A. ISONISHI*, H. YAGI*,
K. KOKAME†, K. SOEJIMA‡, M. MURATA§, T. MIYATA†,*Department of Blood Transfusion Medicine, Nara Medical University, Nara, Japan†Department of Molecular Pathogenesis, National Cerebral and CardiovascularCenter, Suita, Osaka, Japan‡The First Research Department, The Chemo-Sero-Therapeutic Research Institute,
Kumamoto, Japan§Department of Laboratory Medicine, Keio University School of Medicine, Tokyo,
Japan

Running head: Natural history of Upshaw-Schulman syndrome

Correspondence: Yoshihiro Fujimura, Department of Blood Transfusion Medicine,
Nara Medical University, 840 Shijo-cho, Kashihara City, Nara, 634-8522, Japan.
Tel:+81-744-22-3051 (Ext 3289), Fax: +81-744-29-0771,
E-mail: malon@naramed-u.ac.jp1Abbreviation
ADAMTS13 (a disintegrin-like and metalloprote--ase with thrombospondin type 1
motifs 13)
aHUS (atypical hemolytic uremic syndrome)
CAPD (continuous ambulatory peritoneal dialysis)
CR-TTP (chronic relapsing thrombotic thrombocytopenic purpura)
DCM (disease-causing muation)
DDAVP (1-desamino-8-D-arginine vasopressin)
DIC (disseminated intravascular coagulation)
FFP (fresh frozen plasma)
HELLP (hemolysis, elevated liver-enzymes, low platelets)
ITP (idiopathic thrombocytopenic purpura)
MAHA (microangiopathic hemolytic anemia)
SNP (single nucleotide polymorphism)
SLE (systemic lupus erythematosus)
TMA (thrombotic microangiopathies)
TTP (thrombotic thrombocytopenic purpura)
UL-VWFM (unusually large von Willebrand factor multimers)
VWF-CP (von Willebrand factor-cleaving protease)
USS (Upshaw–Schulman syndrome)2Summary
Upshaw–Schulman syndrome (USS) is an extremely rare hereditary deficiency
of ADAMTS13 activity, termed congenital TTP. The clinical signs are usually mild
during childhood, often the isolated thrombocytopenia. But their symptoms become
evident when the patients have infections or get pregnant. We identified 43
USS-patients in Japan, who ranged in age from early childhood to 79 years old.
Analyzing the natural history of these USS patients based on ADAMTS13 genemutations may characterize their clinical phenotypes.
Severe neonatal jaundice that requires exchange blood transfusion, a hallmark of
USS, was found in 18 of 43 patients (42%). During childhood, 25 of 43 patients werecorrectly diagnosed of USS without gender disparity. These 25 patients werecategorized as having “the early-onset phenotype”. Between 15 and 45 years of age,
15 were correctly diagnosed, and interestingly they were all female. The remaining
three patients were all male and were diagnosed when they got older than 45 years ofage, suggesting that they were “the late-onset phenotype”. Two of these 3 males
developed sudden overt TTP when they were 55 and 63 years old. These two men
had two different homozygous ADAMTS13 gene mutations, p.R193W/p.R193W andp.C1024R/p.C1024R, respectively. Both of which were not discovered in the US andWestern countries. In vitro expression studies showed that these two proteins wereconsistently secreted into the culture medium but to a lesser extent and with reduced
activity compared to the wild-type protein. Our results indicate that “the late-onset
phenotype” of USS is formed with ethnic specificity.

Keywords; Upshaw-Schulman syndrome, ADAMTS13 gene mutation, natural
history, clinical phenotype3

Introduction
Upshaw–Schulman syndrome (USS) is a hereditary deficiency in the activity of
von Willebrand factor-cleaving protease (VWF-CP) [1], termed ADAMTS13 (adisintegrin-like and metalloprotease with thrombospondin type 1 motifs 13) [2-4]. In
the absence of ADAMTS13, unusually large VWF multimers (UL-VWFMs) released
from vascular endothelial cells are inappropriately cleaved, which induce platelet
hyperagglutination under high shear stress [5]. Thus, USS is alternatively called
congenital thrombotic thrombocytopenic purpura (TTP). On the other hand,approximately half of congenital atypical hemolytic uremic syndrome (aHUS) cases
are caused by genetic mutations in complement regulatory factors, such as factor H, I,
and B, and membrane cofactor protein, or thrombomodulin [6]. However, themajority of both TTP and HUS occur in the acquired form, and it has been said that
TTP and HUS patients predominantly exhibit neurotropic and nephrotropic signs,
respectively. Further, it is often difficult to discriminate between these two diseases
in clinical practice [7-9] because both diseases are identified based on common
pathological features termed thrombotic microangiopathies (TMAs), which arecharacterized by organ dysfunction due to platelet thrombi in the microvasculature,
consumptive thrombocytopenia, and microangiopathic hemolytic anemia (MAHA)[10].
The classic hallmarks of USS are severe neonatal jaundice with a negative
Coombs test that requires an exchange blood transfusion and repeated childhood
episodes of thrombocytopenia and MAHA that are reversed by infusions of fresh
frozen plasma (FFP) [11]. However, recent studies indicated that the clinical signs of
USS during childhood may be much milder than expected, and often an isolated
thrombocytopenia occurs, causing physicians to sometimes overlook this importantdisease [12].
Despite a lengthy history on clinical diagnoses of USS, only 10 years have passed
since the disease-related enzyme, ADAMTS13, was discovered [3, 4, 13, 14].
Furthermore, USS is an extremely rare disease, and to date, it is estimated that there
have been approximately 100 patients worldwide [15]. In this regard, Nara Medical
University has functioned as a TMA referral center in Japan since 1998 and collecteda large dataset of 919 patients with TMA between 1998−2008 [16]. In this registry,
we identified 41 USS patients in 36 different families who ranged in age from early4

childhood to 79 years old. Subsequently, until the end of March 2011, we haveidentified 2 new USS-patients belonged to different families in Japan. Analyzing thenatural history of these 43 USS-patients will further our understanding of the clinicalsignificance of ADAMTS13, which functions to regulate the size of platelet-thrombithat form in the microvasculature under high shear stress.

Historical backgrounds
In 1953, Dacie et al. [17] reviewed 12 patients with atypical congenital hemolytic
anemia and identified a 6-year-old girl who had experienced repeated episodes ofsevere jaundice, thrombocytopenia, hemolytic anemia, and schistocytes since she
was a newborn. Before first visiting Dacie, this patient had received a splenectomy
but did not improve. She died of renal failure at 7 years of age. This patient was thethird of four children, and both the first and second children were jaundiced at birthand died of hemorrhage at 2 years and 4 days old, respectively. The fourth child andthe parents were asymptomatic. Thus, the authors concluded that these 3 patients
must have a hitherto unrecognized hereditable blood disease.
In the absence of any known concept of TTP, in 1960, Schulman et al. [18]reported an 8-year-old girl who had no coagulation abnormalities but repeatedbleeding episodes due to chronic thrombocytopenia and MAHA. These symptoms
dramatically improved with fresh plasma infusions, suggested that the patient had acongenital deficiency in a “platelet-stimulating factor” in her plasma. In 1978,
Upshaw [19] reported the case of a 29-year-old female who had repeated episodes ofthrombocytopenia and MAHA starting in childhood and was successfully treatedwith plasma infusions. Of note, both Schulman and Upshaw determined that plasma
infusions successfully treated their patients. Rennard and Abe [20] reported a casethat was originally identified by Upshaw with “a slightly decreased level of plasma
cold-insoluble globulin (fibronectin) during the acute phase”, and proposed anomenclature of USS for these types of patients. However, no correlation between
the fibronectin levels and disease activity in USS patients was reported by Koizumi
et al. [21] and Goodnough et al. [22], including Schulman’s original case.
Furthermore, after the thrombopoietin assay was established, Miura et al. [23]reported 5 Japanese USS patients with a normal plasma level of thrombopoietin.

5Thus, all the pathogenic features that were initially postulated for USS have been
entirely excluded by subsequent investigations.
For this reason, the term USS was almost forgotten in 1997, when the assay for
VWF-CP (now ADAMTS13) activity was established. Instead, the practical
diagnostic term of ‘chronic relapsing TTP (CR-TTP)’ has been historically used. This
term was coined by Moake et al. [24], who found that UL-VWFMs were present in
the plasma of 4 CR-TTP patients including the Upshaw’s case during the remission
phase, but disappeared during the acute phase. In 1997, Furlan et al. [25] showed that
4 CR-TTP patients, who were distinct from the cases of Moake et al. [24], lacked
VWF-CP activity, but did not examine the presence of ADAMTS13 inhibitors.
However, it was retrospectively determined that 2 CR-TTP patients in both the casereports by Moake et al. [24] and Furlan et al. [25] had congenital TTP, while theremaining 2 cases in each report had acquired TTP. Under these circumstances, we
re-visited the term USS [11], which included analyzing 3 Japanese patients with USS,and found that they uniformly had a severe deficiency in VWF-CP activity(determined based on the VWFM assay in the presence of 1.5 mol/L urea) and noevidence of inhibitors. The parents of these patients were asymptomatic and had
moderately decreased VWF-CP activity (17−60% of normal), except for one carrier
who had very low VWF-CP activity (5.6% of normal). Later, this carrier was shownto have a unique single nucleotide polymorphism (SNP), a p.P475S mutation in the
ADAMTS13 gene in one allele, which is very common among Japanese people (9.6%
of normal individuals are heterozygous for the p.P475S mutation) [26].
In 2001, Levy et al. provided solid evidence that linked congenital TTP or USS
and ADAMTS13 gene mutations [3], and simultaneously other research groups
successfully purified this enzyme and/or cloned the encoding cDNA [2, 4, 13, 14].

Patients, Materials and Methods
USS patients
Forty-three USS patients (28 females and 15 males) belonging to 38 different
families and their family members were enrolled in this study.
Assays for plasma ADAMTS13 activity and ADAMTS13 inhibitors

6

Between 1998 and 2004, our laboratory examined ADAMTS13 activity using aclassic VWFM assay in the presence of 1.5 mol/L urea following the method of
Furlan et al. [27]. The detection limit of this assay was 3% of the normal control [11].
In 2005, Kato et al. [28] developed a novel chromogenic ADAMTS13-act-ELISA
using a recombinant VWF substrate (termed GST-VWF73-His). The detection limitof this assay was 0.5% of the normal control [28]. Both assays had a high correlation,and since then, the VWFM assay was completely replaced with the act-ELISA. In
our patients with USS, the ADAMTS13 activity was determined at least 2 different
occasions, using their plasmas obtained at more than 2 weeks after the last plasma
infusion therapy. Further, In some experiments with normal individuals as described
below, FRETS-VWF73 assays [29] were used.
The ADAMTS13 inhibitor titers were evaluated using the Bethesda method, andthe values less than 0.5 Bethesda U (BU)/mL were negative, but those between 0.5-1.0 BU/ml were assumed to be marginal.
Assay for IgG-type plasma ADAMTS13 binding antibody titers
Measurement of plasma anti-ADAMTS13 IgG antibody titers in USS-patientswas performed by means of Ferrari et al. [30] with a slight modification as thefollowings. Briefly, the recombinant (r) ADAMTS13 was directly coated tomicro-titer plates, and after blocking with Protein-Free Blocking Buffers (PIERCE,
Rockford, IL), the coated plates were incubated with normal and patient plasma
dilutions. The IgG-type antibody bound to rADAMTS13 was detected by using
horseradish peroxidase-conjugated goat anti-human IgG (AbD Serotec, Kidlington,UK) with a TMB substrate kit (Thermo Scientific, Rockford, USA) at absorbance
450 nm at room temperature for 15 min. The results were calculated as a ratio ofsample OD at each dilution divided by normal plasma OD at each dilution. The IgG
antibody titer of a sample corresponds to the last dilution at which the ratio is above
the cut-off level. This assay kit was kindly provided from Drs. Barbara Plaimauerand Friedlich Scheiflinger of Baxter BioScience. In our laboratory, 25 normal
plasmas (15 males and 10 males, aged between 20 and 40 years) consistently showed
the titer of IgG-type binding antibody with a less than 25-fold dilution (shown as<25X in Table 1).

7

ADAMTS13 gene analysis
All DNA analyses of the ADAMTS13 gene were performed as previously
described [26], with permission from the Ethics Committees of both thesample-collecting hospitals and the institute that performed the gene analysis.
Hereafter, the disease-causing muations (DCMs) of ADAMTS13 will be written inbold letters.

Results
ADAMTS13 SNPs among Japanese individuals
The human ADAMTS13 gene is located on chromosome 9q34. The gene consistsof 29 exons, and the translated enzyme contains 1427 amino acid residues with amulti-domain structure [2, 4]. To date, more than 10 SNPs in ADAMTS13 have been
identified worldwide [3, 26]. Among these, Japanese people (n=3616) had six SNPs
with the following allele frequencies, respectively: p.T339R (exon 9) (2.7%),
p.Q448E (exon 12) (19.2%), p.P475S (exon 12) (5.0%), p.P618A (exon 16) (2.7%),
p.S903L (exon 21) (4.8%), and p.G1181R (exon 25). (2.2%) [31]. Both p.T339R and
p.P618A are almost completely linked in the general Japanese population, but thislinkage may not exist in the Caucasian population as some reports have describedindividuals carrying p.P618A but not p.T339R [32, 33]. Plasma and rADAMTS13
with the Asian-specific SNP, p.P475S [26, 34, 35], has markedly reduced activity
compared to the wild-type protein in both the VWFM assay in the presence of urea
(1.5 mol/L) [26] and the FRETS-VWF73 assay in the absence of urea [36], although
the contribution of this polymorphism to thrombotic diseases has not been
determined.
Recently, we have analyzed the nucleotide sequences of ADAMTS13 in 128
individuals without a history of TTP and identified 14 rare nonsynonymous
mutations. Interestingly, among these 14 mutations, three mutations of p.I673F(exon 17), p.Q723K (exon 18), and c.3220del TACC, were also found as DCMs for
USS in this study (below). Thus, the remaining 11 mutations may or may not be
associated with a reduced activity of plasma ADAMTS13 [31].
Natural history of 43 USS-patients in Japan
8

Until the end of March 2011, we identified 43 USS patients in 38 different families(Family USS-A~LL) who ranged in age from early childhood to 79 years old. Hence,
we present an up-dated natural history of these 43 USS patients together with theirfamily members (Tables 1 and 2).
Family USS-A
Patient: One male (USS-A4) born in 1999
Brief clinical data: The history of USS-A4 (ADAMTS13 genotype: p.R268P/p.Q448E-p.C508Y) before he reached 5 years of age was previously described [11,26, 37]. He currently receives biweekly of FFP infusions (10 mL/kg BW) that are
prepared from several fixed donors to prevent allergic reactions. He contracted theseasonal influenza A virus in 2010 and became severely ill with a reduced platelet
count but did not develop overt TTP. He is currently in good clinical condition andhas not had signs of renal or hepatic dysfunction. Both of his parents are
asymptomatic carriers, but his father, aged 45 years old, has a p.R268P/p.P475S
genotype and very low plasma ADAMTS13 activity at 5.6% of normal by the
VWFM assay in the presence of 1.5 mol/L urea [26] and 3.6% by the chromogenic
ADAMTS13-act-ELISA in the absence of urea (unpublished data).
Family USS-B
Patient: One female (USS-B3) born in 1986
Brief clinical data: USS-B3 (ADAMTS13 genotype: p.Q449X/p.Q449X) is an only
child who was born in Hokkaido to non-consanguineous parents. Her history prior toreaching 5 years of age was previously described [11, 26, 38]. Since childhood, she
has received prophylactic FFP infusions. As a consequence, she was infected with
hepatitis C and has received interferon therapy on two different occasions. In bothinstances, accelerated thrombocytopenia was observed despite the regularprophylactic FFP infusions. Furthermore, during her early childhood, she received
DDAVP (1-desamino-8-D-arginine vasopressin) infusion once that immediately
aggravated her clinical signs, such as hematuria and thrombocytopenia. Currently,
her renal function is normal and her liver function is well preserved (communication
with Dr. Mutsuko Konno). Her parents initially stated that they had a
non-consanguineous marriage. However, a subsequent ancestral analysis revealed9that two great-grandparents of USS-B3 on the paternal and maternal sides migrated
from the same area (a small fisherman’s village) of Iwate to Hokkaido at the end of
the 19th century when Hokkaido was an undeveloped island, and the pioneers settled
from the Japanese mainland (Honshu). This fisherman’s village is located in thenorthern part of Honshu (Tohoku) faced to Pacific sea, an area severely damaged
several times with earthquake and tsunami in the past and most recently in March 11,
2011. In the old days, this small village was isolated from neighbors, and wassurrounded by mountains, suggesting that there were many consanguineous
marriages within this village.
Family USS-C
Patient: One male (USS-C3) born in 1972
Brief clinical data: USS-C3 (ADAMTS13 genotype: c.414+1G>A/c.414+1G>A) isthe last of 4 children to consanguineous parents (first cousins). Notably, the patient’s
elder brother (third sibling) died of melena soon after birth. The history of thispatient was previously described [39, 40]. At 8 years of age, USS-C3 was clinicallydiagnosed with USS. Since then, he has received prophylactic FFP (160 mL)
infusions every two to four weeks. However, his renal function due to chronic
nephritis gradually deteriorated, and in 1995 he required continuous ambulatory
peritoneal dialysis (CAPD). Because of repeated peritonitis associated with CAPD,
his therapy for renal insufficiency was changed to hemodialysis (three times perweek) in 1999. However, his cardiac function decreased, and he eventually died ofchronic heart failure in 2010 at 38 years of age.
Family USS-D
Patient: One female (USS-D4) born in 1978
Brief clinical data: USS-D4 (ADAMTS13 genotype: p.I673F/c.414+1G>A) wasborn as the second of 2 children to non-consanguineous parents. Her history waspreviously described [40, 41].
Family USS-E
Patient: One male (USS-E4) born in 1985
Brief clinical data: USS-E4 (ADAMTS13 genotype: p.I673F/p.C908Y) was born as
10the second of 3 children to non-consanguineous parents. His history was previously
described [40]. The third sibling had Down’s syndrome and died of an unknown
cause soon after birth.
Family USS-F
Patient: One male (USS-F3) born in 1993
Brief clinical data: USS-F3 (ADAMTS13 genotype: p.R193W/c.1244+2T>G) wasborn as the first of 3 children to non-consanguineous parents. His history waspreviously described [40]. He currently receives 120 mL FFP infusions when hedevelops an occasional hemolytic crisis.
Family USS-G
Patient: One female (USS-G3) born in 1987
Brief clinical data: USS-G3 (ADAMTS13 genotype: p.R1123C/c.686+1G>A) wasborn as the third of 4 children to non-consanguineous parents. Her history before shereached 14 years of age was previously described [40]. Of note, her elder sister(second child) had severe jaundice soon after birth and received an exchange bloodtransfusion. She died of intracranial bleeding after a trivial traffic accident when she
was 8 years old. USS-G3 received prophylactic FFP infusions after she wasdiagnosed with USS, but the infusion intervals gradually increased. Under thesecircumstances, she became pregnant at 21 and 22 years of age. During the firstpregnancy, she had a spontaneous abortion at 5 weeks of gestation. During thesecond pregnancy, she delivered a premature baby girl (1446 g BW) at 35 weeks ofgestation after a cesarean section under extensive prophylactic FFP infusions (normal
Japanese female baby at 35 weeks of gestation has a BW of median 2173g).
Interestingly, many of placental small vessels were occupied with hyaline thrombosis(communication with Dr. Michiko Kajiwara, details will be published elsewhere by
the physicians in charge).
Family USS-H
Patient: One male (USS-H3) born in 1951
Brief clinical data: USS-H3 (ADAMTS13 genotype: p.A250V/c.330+1 G>A) wasborn to non-consanguineous parents, but the details were unclear [42]. At 51 years of11

age, he visited a nearby hospital because of a convulsive seizure after
hemorrhoidectomy where he was diagnosed with TTP. He had an episode ofchildhood thrombocytopenia, but there is no additional information. After 51 years ofage, he had two episodes of overt TTP, and both were efficiently treated with FFP
infusions. In July 2002, he experienced a fourth episode of overt TTP that developed
after cholecystectomy, followed by gastrointestinal bleeding that was unsuccessfully
treated with FFP infusions and further complicated by renal failure, which ultimately
resulted in death at 52 years of age.
Family USS-I
Patient: One male (USS-I4) born in 1972
Brief clinical data: USS-I4 (ADAMTS13 genotype: p.H234Q/p.R1206X) was bornas the second of 2 children to non-consanguineous parents. His elder brother died at
2 years of age with clinical signs that were compatible with TTP, as previously
described [43]. At the age of 3 months, USS-I4 developed thrombocytopenia after
receiving the diphtheria/pertussis/tetanus vaccine and was diagnosed with idiopathic
thrombocytopenic purpura (ITP). Since he was 2 years old, he has experienced
repeated overt TTP that has been treated with plasma infusions.
Family USS-J
Patient: One female (USS-J3) born in 1977 and one male (USS-J4) born in 1979,
Brief clinical data: USS-J3 (ADAMTS13 genotype: p.R312C/c.3198delCT) and -J4(ADAMTS13 genotype: p.R312C/c.3198delCT) are the first and second of 3 children
to non-consanguineous parents, respectively. For these 2 patients, severe jaundice
was not noted during the newborn period. At 3 years of age, USS-J3 developed acold followed by purpura with thrombocytopenia and was diagnosed with
disseminated intravascular coagulation (DIC). Since then, she has experienced
repeated episodes of thrombocytopenia and hemolytic anemia, and was diagnosed
with CR-TTP at 6 years of age. USS-J4 had an episode of purpura andthrombocytopenia when he was 5 years old. In 2000, both patients were shown tohave a severe deficiency in ADAMTS13 activity in the absence of ADAMTS13
inhibitors. These 2 patients were not given prophylactic FFP infusions.

12Family USS-K
Patients: Two females (USS-K3 born in 1976 and USS-K4 born in 1978)
Brief clinical data: Patients USS-K3 (ADAMTS13 genotype: p.Y304C/p.T339Rp.Q448E-p.G525D-p.P618A) and -K4 (ADAMTS13 genotype: p.Y304C/p.T339Rp.Q448E-p.G525D-p.P618A) were the first and second to 2 children of
non-consanguineous parents, respectively. The history of these two patients waspreviously reported [12]. In 2003, USS-K3 became pregnant at 27 years old anddeveloped overt TTP at 25 weeks of gestation. She experienced intrauterine fetal
death followed by a caesarean delivery with a hysterectomy. On this occasion, she
was diagnosed with USS. Since then, she has received prophylactic FFP infusions(80−120 mL) every 4 weeks in an out-patient clinic with a good clinical course.
However, at the end of 2010, she had an H1N1 influenza A virus infection that
remarkably aggravated thrombocytopenia and was hospitalized for treatment(communication with Dr. Junji Tomiyama).
In 2003, USS-K4, the younger sibling, became pregnant 2 months after her elder
sister. She developed mild thrombocytopenia without significant clinical signs at 22
weeks of gestation. She received an ADAMTS13 analysis, which confirmed adiagnosis of USS. While being treated with FFP infusions, she delivered a prematurebaby by a cesarean section [12]. Since then, she has received FFP infusions of 80 mL
every 3 weeks. In 2008, 5 years after her first pregnancy, USS-K4 became pregnant
for the second time and received more frequent FFP infusions (160 mL biweekly). At
29 weeks of gestation, her platelet count suddenly and severely dropped. Thus, at 30
weeks of gestation, a cesarean section was performed, and she delivered a baby
(1522g BW) with congenital heart failure due to a ventricular septum defect (details
will be published elsewhere by the physicians in charge).
Family USS-L
Patients: Two females (USS-L2 born in 1967 and USS-L3 born in 1972)
Briefclinical

data:

Both

patients

USS-L2(ADAMTS13

genotype:p.618A-p.Q1302X/p.R125fsX6-p.T339R-p.Q448E) and -L3 (ADAMTS13 genotype:p.618A-p.Q1302X/p.R125fsX6-p.T339R-p.Q448E) were born as the second andfifth of 5 children to non-consanguineous parents. The history of these 2 patients waspreviously described [12]. At 27 years of age, USS-L2 became pregnant. At 27
13weeks of gestation, she had intrauterine fetal death due to a suspected diagnosis of
HELLP (hemolysis, elevated liver-enzymes. low platelets) syndrome. However, shesubsequently had 4 children who were all premature and uniformly born atapproximately 30 weeks of gestation by a cesarean section with oral aspirin. Patient
USS-L3, the younger sister of USS-L2, was diagnosed with ITP at 3 years of age.
She had two pregnancies at 25 and 27 years of age. However, she lost both babies at
23 and 24 weeks of gestation, respectively, under a suspected diagnosis of ‘habitualabortion’.
Family USS-M
Patient: Two females (USS-M3 born in 1969 and USS-M4 born in 1971)
Brief clinical data: Patients USS-M3 (ADAMTS13 genotype: p.R193W /p.R349C)
and USS-M4 (ADAMTS13 genotype: p.R193W/p.R349C) were born as the second
and third of 4 children to non-consanguineous parents. The history of USS-M3 waspreviously described [12]. USS-M3 was primigravida at 33 years of age, and at 20
weeks of gestation she miscarried with overt TTP. The history of her younger sister,
USS-M4, was also previously reported [12]. However, recently Kato et al. [44]reported a more detailed account of the pregnancy of USS-M4, to which we have to
make some corrections. According to that report, USS-M4 became primigravida at
28 years of age. Until 28 weeks of gestation, the pregnancy was uneventful when she
suddenly stopped feeling fetal movement, resulting in intrauterine fetal death and asubsequent diagnosis of HELLP syndrome. One year later, at the age of 29, shebecame pregnant for the second time. She was diagnosed with ITP and treated withprednisolone therapy until 37 weeks of gestation, but with incremental low platelet
counts (~23×109/L). Soon after this, she underwent a cesarean section after receiving
concentrated platelet infusions that transiently increased her platelet counts to
96×109/L. As a result, she delivered a healthy baby. At 32 years of age, she became
pregnant for the third time. At 20 weeks of gestation, she developed DIC followed bymulti-organ failure, despite extensive treatments, including platelet transfusions. By
this time, she had been diagnosed with USS and had received an ADAMTS13
analysis, along with her elder sister, USS-M3. At the age of 36, USS-M4 became
pregnant for a fourth time. With extensive FFP infusions, she continued her
pregnancy until 36 weeks of gestation and delivered a healthy baby (2506 g BW) by
14

natural birth with a skin incision [44].
Family USS-N
Patient: One female (USS-N6) born in 1986
Brief clinical data: Patient USS-N6 (ADAMTS13 genotype: p.H234R-p.P475S/c.3220delTACC) was born as the last of 4 children to non-consanguineous parents.
She had a history of severe neonatal jaundice and childhood thrombocytopenia. Her
clinical data were previously reported [11, 37]. Of note, she developed a thrombotic
occlusion of the left carotid artery at 11 years of age that resulted in right hemiparesis.
Subsequently, she developed hypertension and proteinuria, but these clinical signs
have significantly improved during a long clinical course with prophylactic FFP
infusions, although some neurological sequelae have persisted (communication with
Dr. Seiji Kinoshita).
Family USS-O
Patient: One female (USS-O4) born in 1958
Brief clinical data: Patient USS-O4 (ADAMTS13 genotype: p.I178T /p.Q929X)
was the second of 2 children to non-consanguineous parents. The history of USS-O4
was previously described [12]. At the age of 26, USS-O4 became pregnant. At 23
weeks of gestation, she developed thrombocytopenia and delivered a prematureinfant at 25 weeks of gestation who died soon after birth. After delivery, shedeveloped overt TTP that was rescued with plasma exchange. At 31 years of age, shebecame pregnant for the second time while receiving prophylactic FFP infusions
every one to two weeks. At 8 weeks of gestation, she developed proteinuria andthrombocytopenia, and therefore received more frequent FFP infusions. At 36 weeks
of gestation, she delivered a healthy baby girl.
Family USS-P
Patient: One male (USS-P3) born in 1971
Brief clinical data: The clinical data for patient USS-P3
p.C908Y/p.C322G-p.T323R-p.F324L,

de

novo

(ADAMTS13 genotype:mutation)

were

previously

described [45]. Briefly, USS-P3 was the second of 4 children to non-consanguineousparents. The first and fourth siblings died of an abortion at 6 and 22 weeks of15

gestation, respectively, due to unknown causes. At 3 years of age, USS-P3 hadclinical signs of overt TTP, which was efficiently treated with FFP infusions. He wasrepeatedly treated with FFP infusions when overt TTP developed. Thus, after 21
years of age, the prophylactic FFP infusions were continued.
Family USS-Q
Patient: Two males, (USS-Q1) born in 1983 and (USS-Q2) born in 1988
Brief clinical data: Patients USS-Q1 (ADAMTS13 genotype: p.G227R-p.G1181R/p.C908Y) and -Q2 (ADAMTS13 genotype: p.G227R-p.G1181R/p.C908Y) were thefirst and third of 3 children to non-consanguineous parents. Their detailed clinicaldata during childhood were reported in 1990 [46].
Family USS-R
Patient: One female (USS-R5) born in 1982
Briefclinicaldata:

USS-R5

p.T339R-p.Q448E-p.A606P-p.P618A)(ADAMTS13

genotype:

was

of

the

last

3

p.R193W/
childrentonon-consanguineous parents. The history of USS-R5 was previously reported [12].
Briefly, at 23 years of age, she became pregnant. At 23 weeks of gestation, shedeveloped mild thrombocytopenia, and at 31 weeks of gestation, she had sudden
intrauterine fetal death. After a cesarean section, she developed overt TTP, which wastreated with plasma exchange and steroids. On this occasion, she was diagnosed withUSS after her ADAMTS13 activity and ADAMTS13 inhibitor status were analyzed.
This patient did not receive prophylactic FFP infusions.
Family USS-S
Patient: One male (USS-S3) born in 1982
Brief clinical data: USS-S3 (ADAMTS13 genotype: undetermined) was born tonon-consanguineous parents. Neither his childhood nor family history has beenobtained. The patient was clinically diagnosed with USS at a nearby hospital when
he was 4 years old. Since then, he has received prophylactic FFP infusions every two
weeks at the same hospital. In 2002, USS-S3 was confirmed to have a severe
deficiency in ADAMTS13 activity in the absence of ADAMTS13 inhibitors.
Furthermore, the ADAMTS13 activities for his father and mother were 34.2% and16

47.6%, respectively. This family has not been examined for ADAMTS13 genemutations.
Family USS-T
Patient: One female (USS-T4) born in 1981
Briefclinicaldata:

USS-T4(ADAMTS13

genotype:c.3220delTACC/c.3220delTACC) was born as the second of 2children to non-consanguineousparents. Soon after birth, she developed severe neonatal jaundice and received
exchange blood transfusion for 3 times [47]. One month after birth, she developed
hematuria with thrombocytopenia, which led to a clinical diagnosis of USS. She
received DDAVP infusion once at the age of 4, by which her platelet count promptly
dropped and her clinical signs were aggravated, in accord with a transient
disappearance of larger VWFMs from plasma [47]. Thus, she has received
prophylactic FFP infusions every 2 weeks since 1992. In 1998, USS-T4 was
confirmed to have a severe deficiency in ADAMTS13 activity in the absence of
ADAMTS13 inhibitors. She had a homozygous ADAMTS13 gene mutation ofc.3220del TACC/c.3220delTACC (exon 24).
Family USS-U
Patient: One female (USS-U3) born in 1990
Brief clinical data and remarks: USS-U3 (ADAMTS13 genotype: c.2259delA/c.2259delA) was born as the second of 2 children to consanguineous parents(second cousins). Soon after birth, she developed severe neonatal jaundice that
required an exchange transfusion. She was clinically diagnosed with USS at 4
months of age. In 1998, USS-U3 was confirmed to have a severe deficiency in
ADAMTS13 activity but no ADAMTS13 inhibitors. She was homozygous for an
ADAMTS13 gene mutation of c.2259delA/c.2259delA (exon 19). This patient hascontinued prophylactic FFP infusions.
Family USS-V
Patient: One female (USS-V3) born in 1983
Brief clinical data: USS-V3 (ADAMTS13 genotype: p.W1081X/p.R193W) wasborn as the second of 2 children to non-consanguineous parents. Soon after birth, she17developed severe neonatal jaundice that required an exchange blood transfusion. She
was clinically diagnosed with USS at 4 years of age. In 1998, USS-V3 was
confirmed to have a severe deficiency in ADAMTS13 activity but no ADAMTS13
inhibitors. She had a compound heterozygous ADAMTS13 gene mutation with
p.W1081X (exon 24) from her father and p.R193W (exon 6) from her mother. The
patient has been administered FFP infusions on demand.
Family USS-W
Patient: One female (USS-W4) born in 1990
Brief

clinical

data

and

remarks:

p.Q448E-p.G550R/p.P475S) was born

USS-W4
as(ADAMTS13

genotype:

the second of 2 children to

non-consanguineous parents. She did not have episodes of severe jaundice as a
newborn.

At

2

years

of age,she developed

pneumonia followedbythrombocytopenia. Since then, she has had repeated episodes of thrombocytopenia
and hemolytic anemia that have coincided with various infections, resulting in adiagnosis of Evans syndrome. In 2005, USS-W4 was confirmed to have a severe
deficiency in ADAMTS13 activity in the absence of ADAMTS13 inhibitors. An
ADAMTS13 gene analysis in USS-W4 suggested that she was a compound
heterozygote with a p.G550R (exon 14) mutation from her father and an unidentified
DCM from her mother. This patient has received prophylactic FFP infusions every
two weeks.
Family USS-X
Patient: One female (USS-X5) born in 1963
Brief clinical data: USS-X5 (ADAMTS13 genotype: p.G1181R/p.P475S) was thelast of 4 children to non-consanguineous parents. She did not have severe neonatal
jaundice or childhood thrombocytopenia. She had two pregnancies at the ages of 24
and 26 years that yielded two children. During her first pregnancy, she had
pregnancy-induced hypertension, but the details are unknown. At 32 years of age,she developed nephrotic syndrome, followed by repeated hemolytic anemia andthrombocytopenia of an unknown cause. None of the laboratory markers wereindicative of connective tissue disease. She underwent a splenectomy at the age of 36.
In 2004, she had a relapse of nephrotic syndrome with hemolytic anemia and18

thrombocytopenia that was treated with high-dose steroid therapy with limited
success. At this time, her plasma ADAMTS13 activity levels and ADAMTS13
inhibitor status were examined, and she was determined to have a severe deficiency
in ADAMTS13 activity in the absence of ADAMTS13 inhibitors. The same results
were obtained 6 months later with a different plasma specimen. An ADAMTS13 gene
analysis in USS-X5 identified no DCMs, but revealed two SNPs of p.P475S from her
mother and p.G1181R from her father. In 2007, she developed systemic lupus
erythematosus (SLE) and was moved to a different hospital, after which we wereunable to follow her clinical and laboratory data. From these results, USS-X5 could
be considered to be a possible USS.
Family USS-Y
Patient: One female (USS-Y3) born in 1960
Brief clinical data: USS-Y3 (ADAMTS13 genotype: p.G385E/ p.R1206X) was thelast of 3 children to non-consanguineous parents. It is unclear whether this patient
had a history of severe neonatal jaundice. However, during childhood she had an
episode of thrombocytopenia and was diagnosed with ITP. She has a history of fresh
whole blood transfusions, although the details are unclear. Since then, she had noremarkable changes. However, at 45 years of age, she suddenly developed
thrombocytopenia and hemolytic anemia, leading to a diagnosis of Evans syndrome.
On this occasion, her physician noted many schistocytes on her blood film, and
USS-Y3 was confirmed to have a severe deficiency in ADAMTS13 activity in theabsence of ADAMTS13 inhibitors. An ADAMTS13 gene analysis determined that she
was a compound heterozygote with p.G385E (exon 10) from her father andp.R1206X (exon 26) from her mother.
Family USS-Z
Patient: One female (USS-Z3) born in 1971
Brief clinical data: USS-Z3 (ADAMTS13 genotype: p.R193W /p.R193W) was thelast of 3 children to consanguineous parents (second cousins). Her clinical data werepreviously described [12]. Briefly, she became pregnant for the first time at 25 yearsof age, and at 12 weeks of gestation, she developed thrombocytopenia and wasdiagnosed with pregnancy-associated ITP. At 32 weeks of gestation, she had a live
19

birth by cesarean section, and then developed overt TTP, which was treated withdaily plasma exchange. This patient was referred to our laboratory in 1998, and
USS-Z3 was confirmed to have a severe deficiency in ADAMTS13 activity in theabsence of ADAMTS13 inhibitors. This patient did not receive prophylactic FFP
infusions, and she had more than five TTP episodes between 1998−2005. Each
episode was treated with 320 mL plasma infusions. She has been receiving
prophylactic FFP infusions every two weeks.
Family USS-AA
Patient: One female (USS-AA3) born in 1987
Brief clinical data: USS-AA3 (ADAMTS13 genotype: not performed) was the firstof 2 chidren born to non-consanguineous parents. She had neither an apparent historyof severe neonatal jaundice nor thrombocytopenia during childhood. At 19 years ofage, she suddenly developed petechiae, and her laboratory data indicated severe
thrombocytopenia and hemolytic anemia. Thus, her ADAMTS13 activity was
examined and revealed a severe deficiency in ADAMTS13 activity but no
ADAMTS13 inhibitors. Plasma exchange therapy was performed, and her platelet
counts normalized. One month later, her ADAMTS13 activity and ADAMTS13
inhibitor status were re-tested and yielded the same results. In addition, her family
members had the following ADAMTS13 activities: father (32%), mother (53%), andyounger sister (46%). An ADAMTS13 gene analysis was not performed in this family
because permission was not obtained. In 2009, we determined that USS-AA3 had anormal platelet count (201×109/L), but her ADAMTS13 activity was still very low(<0.5% of normal) with no ADAMTS13 inhibitors. Since this point, we have been
unable to obtain more up-dated information on this patient.
Family USS-BB
Patient: One male (USS-BB3) born in 1947
Brief clinical data: USS-BB3 (ADAMTS13 genotype: p.R193W/p.R193W) was thefirst of 3 children to consanguineous parents (first cousins). His younger sister diedof ‘purpura of unknown cause’ at 23 years of age. It is unclear whether USS-BB3
experienced

episodesofseverejaundiceasa

newbornorchildhoodthrombocytopenia. He was married and had 3 children. At 55 years of age, he20

developed overt TTP, which was successfully treated with plasma exchange. Whenhe was 59 years old, he developed hematuria and was admitted to a nearby hospital,
where an ADAMTS13 analysis showed that he had a severe deficiency in
ADAMTS13 activity but no ADAMTS13 inhibitors. An ADAMTS13 gene analysis
indicated that he was a homozygote with p.R193W (exon 6) (communication with
Dr. Toshi Imai, details will be reported by the physicians in charge).
Family USS-CC
Patient: One male (USS-CC5) born in 2004
Brief clinical data: USS-CC5 (ADAMTS13 genotype: p.Q723K/p.R398C) was thelast of 3 children to non-consanguineous parents. Soon after birth, he developed
Coombs-negative hemolytic anemia and was treated with an exchange bloodtransfusion. At 7 months of age, he became infected with influenza A virus that
aggravated his thrombocytopenia and hemolytic anemia. At 32 months of age, hesuddenly developed a transient disturbance in his ability to walk and converse. On
this occasion, an ADAMTS13 analysis revealed that USS-CC5 had a severe
deficiency in ADAMTS13 activity but no ADAMTS13 inhibitors. An ADAMTS13
gene analysis indicated that he was a compound heterozygote with p.Q723K (exon18) from his father and p.R398C (exon 10) from his mother. Since he was diagnosed
with USS, he has received prophylactic FFP infusions every two weeks.
Family USS-DD
Patient: One female (USS-DD5) born in 2007
Brief clinical data: USS-DD5 (ADAMTS13 genotype: p.R268P/p.Y304C) was bornas the last of 3 children to non-consanguineous parents. One day after birth, thepatient developed hematuria, petechiae, moderate jaundice, and thrombocytopenia,
suggesting immune thrombocytopenia. A platelet transfusion was performed that
subsequently aggravated her jaundice, which was ameliorated with albumin infusions
and phototherapy from three directions. Therefore, an exchange blood transfusion
was not performed. Her platelet counts were maintained around 60−100×109/L, andat 15 days of age the physician infused FFP at a dose of 10 mL/kg due to suspected
USS. This treatment markedly increased her platelet counts (written informationfrom Dr. Hitoshi Miyabayashi). One month after birth, an ADAMTS13 analysis
21

showed that the patient had a severe deficiency in ADAMTS13 activity but no
ADAMTS13 inhibitors. An ADAMTS13 gene analysis determined that USS-DD5
was a compound heterozygote with p.R268P (exon 7) from her father and p.Y304Y(exon 8) from her mother. The patient did not receive prophylactic FFP infusions.
Family USS-EE
Patient: One male (USS-EE4) born in 2003
Brief

clinical

data

and

remarks:

USS-EE4(ADAMTS13

genotype:c.2259delA/c.2259delA) was born as the second child of bi-ovular twins by acaesarean delivery at 37 weeks of gestation to consanguineous parents (second
cousins). Soon after birth, USS-EE4 received an exchange blood transfusion under adiagnosis of DIC. However, the other twin did not have these complications. Since
then, USS-EE4 has continued to experience mild thrombocytopenia. At 18 months ofage, his platelet count dropped to 11×109/L, and schistocytes appeared on a blood
film when the patient had a rotavirus infection. The patient subsequently experienced
repeated episodes of thrombocytopenia and hemolytic anemia associated with avariety of infectious diseases. At the age of 4 years and 7 months, the patient wasadmitted to a nearby hospital because of exacerbated asthmatoid bronchitis together
with severe thrombocytopenia (4×109/L). After being diagnosed with ITP, the patient
was administered high-dose immunoglobulin therapy with steroid therapy, but there
was no clinical improvement (written information from Dr. Masahiro Migita). An
ADAMTS13 analysis showed a severe deficiency in ADAMTS13 activity but no
ADAMTS13 inhibitors. An ADAMTS13 gene analysis in USS-EE4 identified ahomozygous mutation of c.2259delA (exon 19). This patient did not receive
prophylactic FFP infusions.
Family USS-FF
Patient: One female (USS-FF3) born in 1991
Brief clinical data: USS-FF3 (ADAMTS13 genotype: p.Q449X/p.Q449X) was bornas the first of 2 children to non-consanguineous parents [48]. As a newborn, thepatient had moderate jaundice that required phototherapy, but no exchange bloodtransfusion was required. She also had a history of chronic thrombocytopenia as a
newborn, but did not receive specific treatment. At 6 years of age, she developed
22

severe thrombocytopenia and hemolytic anemia, and an ADAMTS13 analysis
revealed a severe deficiency in ADAMTS13 activity but no ADAMTS13 inhibitors.
An ADAMTS13 gene analysis was performed at the laboratory of Dr. David Ginsburg,where a homozygous mutation of p.Q449X (exon 6) was identified ([40] and written
communication with Dr. Yoji Sasahara). Since the USS diagnosis was confirmed, thepatient has received FFP infusions (5 mL/kg) every two weeks.
Family USS-GG
Patient: One male (USS-GG2) born in 1931
Brief clinical data: USS-GG2 (ADAMTS13 genotype: p.C1024R/p.C1024R) wasborn as the fifth of 7 children to consanguineous parents (first cousins). The
ancestors of this family can be traced back to Kochi on Shikoku Island. The first two
siblings died of an unknown etiology during childhood. Interestingly, USS-GG2
suddenly developed overt TTP with neurological signs at 63 years of age and wasadmitted to a nearby hospital. Before this, he had never had an episode of anemia or
thrombocytopenia. He was treated with plasma infusions because plasma exchange
was not readily available at that hospital. The next day, his neurological signs
dramatically improved. He subsequently has experienced repeated episodes of overt
TTP, resulting in a clinical diagnosis of CR-TTP, which was treated with biweekly
prophylactic FFP infusions (320−480 mL per each). However, at 77 years of age, he
had cerebellar bleeding. Thus, he received an ADAMTS13 analysis that showed asignificant reduction in ADAMTS13 activity (2.4−3.4% of normal on 3 different
occasions) but no ADAMTS13 inhibitors. An ADAMTS13 gene analysis revealed
that he was a p.C1024R/p.C1024R (exon 24) homozygote, confirming the USS
diagnosis. Under prophylactic FFP infusions, he was alive until 79 years old, but hesuddenly died of stroke in 2011 at the age of 79 (communication with Dr. Fumihiro
Taguchi, details will be published elsewhere by the physician in charge).
Family USS-HH
Patient: One female (USS-HH4) born in 2003
Brief clinical data: USS-HH4 (ADAMTS13 genotype: p.Q449X/ c.4119delG) wasborn as the second of 2 children to non-consanguineous parents. Soon after birth, shedeveloped Coombs-negative hemolytic anemia that was treated with an exchange
23

blood transfusion. In 2005, she had three episodes of thrombocytopenia andhemolytic anemia that occurred concomitantly with fever or the chicken pox.
Therefore, her ADAMTS13 activity was assayed, and she was determined to have asevere deficiency in ADAMTS13 activity but no ADAMTS13 inhibitors. An
ADAMTS13 gene analysis revealed that she was a compound heterozygote with
p.Q449X (exon 12) from her father and c.4119delG (exon 29) from her mother.
Although she had a history of severe neonatal jaundice followed by an exchange
blood transfusion, she subsequently has only had mild clinical signs and has notreceived prophylactic FFP infusions. She receives FFP infusions only when her
platelet count severely drops.
Family USS-II
Patient: One female (USS-II3) born in 1977
Brief clinical data: USS-II3 (ADAMTS13 genotype: not performed) was born by acesarean section as the fourth and final pregnancy of her mother at 40 weeks ofgestation. Her parents were non-consanguineous. Her mother had previously had two
abortions (5 and 3 months of gestation) and a stillbirth (9 months of gestation) before
USS-II3 was born. On the second day after birth, USS-II3 was treated with an
exchange blood transfusion because of severe jaundice and thrombocytopenia. One
month later, the patient was discharged but the thrombocytopenia continued,
suggesting ITP. Since then, she has received whole blood transfusions when her
platelet counts have dropped to 10×103/L. At 9 months of age, the patient was
clinically diagnosed with TTP. She was administered FFP infusion when severe
thrombocytopenia developed. At 10 years of age, she underwent a splenectomy but
there was no clinical improvement. The prophylactic FFP infusions have continued.
At 21 years of age, she was diagnosed with USS after it was determined that she had
a severe deficiency in ADAMTS13 activity but no ADAMTS13 inhibitors. She
currently receives prophylactic FFP infusions (120 mL) every week.
Family USS-JJ
Patient: One male (USS-JJ3) born in 1980
Brief clinical data: USS-JJ3 (ADAMTS13 genotype: c.1885delT/p.C908Y) wasborn as the last of 4 children to non-consanguineous parents. He had no history of24exchange blood transfusions as a newborn. At 2 years of age, he suddenlycomplained of abdominal pain and developed hemolytic anemia, hematuria, andthrombocytopenia. On this occasion, he was diagnosed with acute renal insufficiency
due to diarrhea-negative atypical HUS at a nearby hospital. Under this diagnosis, hereceived conservative therapy, including heparin, anti-platelet drugs, and red blood
cell transfusion, but no platelet or FFP infusions. During the next 14 years, heoccasionally experienced overt HUS. At 12 years of age, his physician noticed that
the FFP infusions were highly effective and improved his clinical manifestations,suggesting a clinical diagnosis of CR-TTP. Since 1996, he has received FFP
infusions (160−240 mL per each) when his platelet counts have dropped below
100×109/L, and has been administered FFP infusions with a greater volume(320−480 mL) during instances of overt TTP. In 1998, he was diagnosed with USS
after an ADAMTS13 analysis revealed a severe deficiency in ADAMTS13 activity
but no ADAMTS13 inhibitors. Furthermore, he was a heavy drinker, which increased
the frequency of overt TTP. Under these unhealthy conditions, the prophylactic FFP
infusions were sometimes interrupted. Thus, when he was 25 years old, heexperienced a cerebral infarction and the prophylactic FFP infusions were re-started.
Nevertheless, one year later, he had severe renal insufficiency that required
hemodialysis. Thus, he currently receives maintenance dialysis therapy andprophylactic FFP infusions of 240 mL per week. In 2009, an ADAMTS13 activity
analysis revealed a severe deficiency in ADAMTS13 activity but no ADAMTS13
inhibitors. An ADAMTS13 gene analysis revealed that he was a compound
heterozygote with c.1885delT (exon 16) and p.C908Y (exon 21), but that was not
performed to his parents.
Family USS-KK
Patient: One female (KK3) born in 1976
Brief clinical data: USS-KK3 (ADAMTS13 genotype: not performed) was born as
the second of 3 children to non-consanguineous parents. She had no history of
exchange blood transfusion during the newborn period. At the age of 2, shedeveloped thrombocytopenia and was diagnosed of ITP. She received a steroid
therapy for thrombocytopenia at the age of 17 but without improvement, and thenreceived splenectomy. When she was a university student at the age of 20, she25

developed thrombocytopenia and hemolytic anemia after heavily drinking alcohol,
and on this occasion she was clinically diagnosed of TTP at Shinshu university
hospital in Nagano. A diagnosis of CR-TTP was made by Dr. Miha Furlan at
University of Bern in 1998, after analyzing ADAMTS13, which showed a severe
deficiency of the activity but without its inhibitors (these results were re-confirmed
in March 2011 using chromogenic act-ELISA). Her mother and two siblings had aslightly decreased ADAMTS13 activity (25~50%) (communication with Drs.
Fumihiro Ishida and Hikaru Kobayashi). Now, the patient receives the prophylactic
FFP infusions (240 ml per each) every 3 weeks. The ADAMTS13 gene analysis has
not been performed.
Family USS-LL
Patient: One female (LL4) born in 1981.
Briefclinicaldata:

USS-LL4(ADAMTS13

genotype:

p.C438S/p.T339R-p.Q448E-p.P618A-p.G909R) was born as the last of 2 children to
non-consanguineous parents. She had no history of exchange blood transfusion
during the newborn period. At the age of 14, she was diagnosed of HUS of unknown
etiology, and received hemodialysis. During 1996-2001, she repeated overt TTP
when she had various infectious diseases, and in each occasion she was treated with
FFP infusions. In 2002, she was diagnosed of USS after analyzing ADAMTS13,
showing a severe deficiency of the activity but without its inhibitors in our laboratory.
Since then, however, a low-titer ADAMTS13 inhibitor (less than 1.4 BU/mL) was
detected in a few occasions, but its clinical significance was not well evaluated. Herparents and elder sister are asymptomatic and have a slightly decreased ADAMTS13
activity (27~57%). The ADAMTS13 gene analysis in this patient revealed acompound heterozygote of p.C438S (exon 12) from her father and p.G909R (exon21) from her mother. She had been treated with FFP infusions on demand. Most
recently, she has become pregnant, and her inhibitor titers are kept below 0.5 BU/ml.
Thus, the prophylactic FFP infusions (10 ml/kg BW) have been started biweekly, andso far no increase of ADAMTS13 inhibitor titer has been observed (communication
with Dr. Yoshiyuki Ogawa).
Characterization and allelic numbers of ADAMTS13 gene mutations in Japanese26patients with USS
Of our 43 USS-patients, 39 received an ADAMTS13 gene analysis while it was
not performed in 4 patients (USS-S3, AA3, II3 and KK3). Nine of these 39
USS-patients were homozygous for ADAMTS13 gene mutations, and 29 were thecompound heterozygotes, including one patient (USS-W4) with p.G550R mutation
on one allele while DCM on the other allele was unidentified. In the remaining one
patient (USS-X5), two SNPs (p.P475S/p.G1181R) but not DCMs were identified oneach allele. Of these 39 USS-patients, five were siblings that each belonged todifferent families. Thus, the 65 [2 × (39−5)-3] allelic numbers of DCMs in thesepatients are summarized in Table 3. Interestingly, these mutations are quite different
from those reported in the US and Western countries [3, 49-66], except for p.R268P.
However, the p.R349C mutation was previously reported in a Chinese USS patientin Hong Kong [67], and c.330+1G >A was identified in a Korean patient [68]. Thus,
it is likely that specific ADAMTS13 gene mutations are more common among certain
ethnicities. In this regard, the mutation of p.R268P is quite unique, because of thesame mutation was reported by Veyradier et al. [55] in France, but in a Haitianpatient.
The ADAMTS13 gene mutation with the highest frequency in Japan was
p.R193W (n=8), followed by the remaining alleles in order of descending frequency:
p.Q449X (n=5), p.C908Y (n=4), c.2259delA (n=4), etc. The p.Q449X mutation was
localized to the northern part (Tohoku) of Honshu, c.2259delA to Kyushu, p.C908Y
to western Japan, and p.R193W to a relatively wide area across Japan but more
frequently in western Japan, suggesting some geographical specificity in thesemutations. (Fig. 1)
Plasma levels of ADAMTS13 activity, ADAMTS13 inhibitor, and IgG-type
anti-ADAMTS13 binding antibody in USS-patients
Most of our USS-patients had the plasma levels of ADAMTS13 activity with aless than 0.5% of the normal (Table 1), but USS-GG2 alone had the ADAMTS13
activity of 2.4-3.4% of the normal, measured in 3 different occasions, as describedabove. Further, seven USS-patients (USS-F3, J3, K3, H3, Q1, S3, and LL4) had a
trace amount of ADAMTS13 activity (0.6-1.8% of the normal) in some occasions, ofwhom 4 patients (USS-J3, K3, Q1, and LL4) had the ADAMTS13 activity below
270.5% of the normal in different occasions The reason for this slight variation ofplasma ADAMTS13 activity in our patients is presently unknown.
As for the ADAMTS13 inhibitors, all of our USS-patients had the plasma levelof less than 0.5 BU/ml, but with one exception (USS-LL4), who showed the inhibitor
titers ranging from less than 0.5 to 1.4 BU/ml.
In regard to the IgG-type anti-ADAMTS13 binding antibody, 36 of 43
USS-patients did not have it (shown as the titer of 25X or less than 25X in Table 1).
However, 7 patients (USS-K3, K4, X5, AA3, EE4, II3, and LL4) had the antibody
titers ranged from 50X to 400X in some occasions. Clinical significance of the
IgG-type anti-ADAMTS13 binding antibody is also unclear at moment, but notably 6of these 7 patients are female.

Discussion
Since ADAMTS13 was originally discovered, one major question has been why
USS-patients who consistently lack ADAMTS13 activity do not always experience
acute symptoms of overt TTP. Furthermore, symptoms often become evident only
when the patients have infections or become pregnant [12, 69]. In both instances,vascular endothelial cell injury may be involved, and these cases have been
indirectly associated with elevated plasma levels of cytokines or soluble
thrombomodulin [70]. Consistent with these observations, studies on two different
groups of ADAMTS13 gene knock-out mice revealed that UL-VWFMs weredetectable in the blood, although the mice did not exhibit acute symptoms [71, 72].
Considering these results, investigators have assumed that a deficiency in
ADAMTS13 activity is prothrombotic, but alone is insufficient to provoke acute
symptoms. Thus, second hits or triggers must exist. Related to this hypothesis, it has
been said that there are two clinical features of USS, termed the “early-onset” and“late-onset” phenotypes. To partially address this question, we have extensively
analyzed the natural histories and ADAMTS13 genotypes of 43 Japanese patientswith USS.
This study has two advantages. One advantage is that Japan has four basic small
islands, Hokkaido, Honshu, Shikoku, and Kyushu, that are favorable for tracing theancestral roots of a targeted USS family. This is because USS patients tend to live
28

near their parents or healthy relatives in order to receive medical support when they
develop overt signs of TTP. In fact, before ADAMTS13 was discovered in 2001, ninepatients were clinically diagnosed with USS or congenital CR-TTP in Japan, andnone of these patients have moved to other areas or countries. The other advantage ofthis study can be attributed to the development of two convenient ADAMTS13
activity assays in our country, FRETS-VWF73 [29] and the chromogenic
ADAMTS13-ac-ELISA [28]. Both assays are now used worldwide, and in 1998 Nara
Medical University started voluntarily using the VWFM assay to meet the requests
of clients across Japan. In 2005, the act-ELISA shortened the time required todiagnose TTP, and more importantly facilitated the identification of new
USS-patients in Japan.
Although severe neonatal jaundice that requires exchange blood transfusion has
been a hallmark of USS, this clinical sign was present in 18 of 43 (42%) patients inthis study. Because of this clinical sign, 4 (/18) physicians correctly diagnosed theirpatient with USS before the patient reached 6 months of age, and 10 (/18) physiciansrequired 6 years to reach a USS diagnosis. On the other hand, among 25 USS
patients without severe newborn jaundice, two (/25) were correctly diagnosed within
6 months of age, and six (/25) were diagnosed within 6 years. As a whole, 25 of 43(58%) USS patients were correctly diagnosed before they reached 15 years of age,
including 12 females and 13 males, indicating that there is no gender disparity indiagnosing USS during childhood. These 25 patients would be unanimously
considered to have the “early-onset phenotype”. However, the remaining 18 USSpatients were diagnosed after 15 years of age. This raises the question of whether
these patients were the true “late-onset phenotype” or not. One particularlyinteresting result was that 15 (/18) patients were diagnosed between 15 and 45 yearsof age, and interestingly they were all female. Furthermore, among these 15 female
patients, nine were diagnosed in association with pregnancy. On the other hand, theremaining 3 patients (USS-H3, -BB3, and –GG2) were diagnosed after 45 years ofage, and they were all male, which sharply contrasts the previous scenario. Thus, thenatural history of these 3 male patients appeared to be an excellent means to analyze
the pathogenesis of the “late-onset phenotype”. Among these patients, USS-H3 witha p.A250V/c.330+1G>A genotype had an episode of thrombocytopenia, but there arefew clinical details and the patient died of renal failure in 2002 [42], Thus, no further
29

results on USS-H3 are available.
However, two other males, USS-BB3 and USS-GG2, had received annual healthexaminations during adulthood, and there were no apparent abnormalities until
sudden and overt TTP developed at 55 and 63 years of age, respectively. This may
indicate that the clinical signs of TTP were very mild during their childhood andadulthood, and any symptoms might have been attributed to isolated mild
thrombocytopenia. Interestingly, these two elderly men carried two different
homozygous

ADAMTS13

gene

mutations,p.R193W/p.R193W

and

p.C1024R/p.C1024R, respectively. We previously reported that the p.R193W protein
was present in the plasma of patient USS-Z3 [12, 73]. In this study we also
determined that the p.C1024R protein was present in the plasma of patient USS-GG2(data not shown). Furthermore, in vitro expression studies using HeLa cells that weretransfected with either of these two mutant gene plasmids showed that each protein
was consistently secreted into the culture medium but had much reduced activity
compared to the wild-type protein ([39] and unpublished data). Consistent with theseobservations, the ADAMTS13 activity of patient USS-GG2 was mildly reduced(2.4−3.4% of the normal) on 3 different occasions. As for the homozygous
p.R193W/p.R193W mutation, we identified another female patient (USS-Z3) who
was correctly diagnosed with USS at 27 years of age as a result ofpregnancy-associated TTP at 25 years of age. Her past history was well recorded,
and indicated that she had mild jaundice as a newborn and thus did not receive an
exchange blood transfusion. However, she was diagnosed with ITP with isolated
thrombocytopenia at 7 years of age. Taken together, these results indicate that thephenotype of the homozygous p.R193W/p.R193W mutation is mild. Therefore,
patients carrying this mutation would presumably have mild thrombocytopenia
during childhood, as shown in USS-Z3, unless they are exposed to strong stimuli
such as a cytokine storm during influenza virus infection. However, afteradolescence the gender disparity apparently determines the fate of these
USS-patients. Pregnancy undoubtedly is a strong inducer of overt TTP in female
USS-patients, although the pathogenesis is not fully elucidated. However, it is now
well established that plasma VWF levels remarkably increase as gestation progresses,
along with the appearance of UL-VWFMs, which are accompanied by reduced
ADAMTS13 activity due to consumption, even in normal pregnant women [74,75].
30

Thus, in pregnant USS women, an enormous excess of the substrate (larger VWFM)
relative to the ADAMTS13 enzyme is the most plausible pathogenic mechanism.
As a consequence, our studies here have re-confirmed that pregnancy, influenza
infection, and DDAVP administration can be the strong triggers inducing overt TTP
in USS-patients. Besides, now it is indicated that the aging, interferon therapy, andheavily drinking alcohol could be the additional modifiers aggravating clinical signsof USS-patients.
Given that the p.R193W mutation is a frequent DCM for USS in Japan, malepatients carrying this mutation might not exhibit clinical signs of thrombosis at a
younger age. However, as they age, multi-factorial endogenous and exogenous
causes mentioned above would facilitate thrombotic events, leading to brain
infarctions and chronic renal failure as a result of microcirculation disturbances. We
speculate that thrombotic events in the brain or kidney, which still have an unknown
pathogenesis, might result from ADAMTS13 gene abnormalities. Our examination of
the natural history in this large cohort of USS-patients with ADAMTS13 mutations
may shed light on these important diseases. Thus, here we emphasize again an
importance of the assay for ADAMTS13 activity as a routine test to make and/or
exclude a diagnosis of USS, when physicians meet the patients withthrombocytopenia of unknown etiology, not only in childhood but also in adulthood.
Acknowledgements
This work was supported in part by research grants from the Ministry of Health,
Labor, and Welfare of Japan, and the Ministry of Education, Culture, Sports, Scienceand Technology of Japan. YF dedicates this paper to the late Professors Theodore S.
Zimmerman and Hiromu Fukui, who both encouraged me to be involved in the
research on VWF and its clinical application.
Disclosure of Conflict of Interests
YF is a clinical advisory board for Baxter Bioscience.

31References
1

Fujimura Y, Matsumoto M, Yagi H, Yoshioka A, Matsui T, Titani K. Von

Willebrand factor-cleaving protease and Upshaw-Schulman syndrome. Int J Hematol.
2002; 75: 25-34.
2

Zheng X, Chung D, Takayama TK, Majerus EM, Sadler JE, Fujikawa K.

StructureofvonWillebrandfactor-cleaving

protease(ADAMTS13),ametalloprotease involved in thrombotic thrombocytopenic purpura. J Biol Chem.
2001; 276: 41059-63.
3

Levy GG, Nichols WC, Lian EC, Foroud T, McClintick JN, McGee BM,

Yang AY, Siemieniak DR, Stark KR, Gruppo R, Sarode R, Shurin SB,
Chandrasekaran V, Stabler SP, Sabio H, Bouhassira EE, Upshaw JD, Jr., Ginsburg D,
Tsai HM. Mutations in a member of the ADAMTS gene family cause thrombotic
thrombocytopenic purpura. Nature. 2001; 413: 488-94.
4

Soejima K, Mimura N, Hirashima M, Maeda H, Hamamoto T, Nakagaki T,

Nozaki C. A novel human metalloprotease synthesized in the liver and secreted into
the blood: possibly, the von Willebrand factor-cleaving protease? J Biochem. 2001;
130: 475-80.
5Sadler JE. Von Willebrand factor, ADAMTS13, and thrombotic

thrombocytopenic purpura. Blood. 2008; 112: 11-8.
6

Waters AM, Licht C. aHUS caused by complement dysregulation: newtherapies on the horizon. Pediatr Nephrol. 2011; 26: 41-57.
7

George JN. Clinical practice. Thrombotic thrombocytopenic purpura. N

Engl J Med. 2006; 354: 1927-35.
8Veyradier A, Obert B, Haddad E, Cloarec S, Nivet H, Foulard M, Lesure F,

Delattre P, Lakhdari M, Meyer D, Girma JP, Loirat C. Severe deficiency of thespecific von Willebrand factor-cleaving protease (ADAMTS 13) activity in a
subgroup of children with atypical hemolytic uremic syndrome. J Pediatr. 2003;
142: 310-7.
9Remuzzi G, Galbusera M, Noris M, Canciani MT, Daina E, Bresin E,

Contaretti S, Caprioli J, Gamba S, Ruggenenti P, Perico N, Mannucci PM. vonWillebrand factor cleaving protease (ADAMTS13) is deficient in recurrent andfamilial thrombotic thrombocytopenic purpura and hemolytic uremic syndrome.

32

Blood. 2002; 100: 778-85.
10

Moake JL. Thrombotic microangiopathies. N Engl J Med. 2002; 347:

589-600.
11

Kinoshita S, Yoshioka A, Park YD, Ishizashi H, Konno M, Funato M,

Matsui T, Titani K, Yagi H, Matsumoto M, Fujimura Y. Upshaw-Schulman syndrome
revisited: a concept of congenital thrombotic thrombocytopenic purpura. Int J
Hematol. 2001; 74: 101-8.
12

Fujimura Y, Matsumoto M, Kokame K, Isonishi A, Soejima K, Akiyama N,

Tomiyama J, Natori K, Kuranishi Y, Imamura Y, Inoue N, Higasa S, Seike M,
Kozuka T, Hara M, Wada H, Murata M, Ikeda Y, Miyata T, George JN.
Pregnancy-induced thrombocytopenia and TTP, and the risk of fetal death, inUpshaw-Schulman syndrome: a series of 15 pregnancies in 9 genotyped patients. Br
J Haematol. 2009; 144: 742-54.
13

Fujikawa K, Suzuki H, McMullen B, Chung D. Purification of human vonWillebrand factor-cleaving protease and its identification as a new member of themetalloproteinase family. Blood. 2001; 98: 1662-6.
14

Gerritsen HE, Robles R, Lämmle B, Furlan M. Partial amino acid sequenceof purified von Willebrand factor-cleaving protease. Blood. 2001; 98: 1654-61.
15

Tsai HM. Pathophysiology of thrombotic thrombocytopenic purpura. Int J

Hematol. 2010; 91: 1-19.
16

Fujimura Y, Matsumoto M. Registry of 919 patients with thrombotic

microangiopathies across Japan: database of Nara Medical University during
1998-2008. Intern Med. 2010; 49: 7-15.
17

Dacie JV, Mollison PL, Richardson N, Selwyn JG, Shapiro L. Atypicalcongenital haemolytic anaemia. Q J Med. 1953; 22: 79-98.
18

Schulman I, Pierce M, Lukens A, Currimbhoy Z. Studies onthrombopoiesis. I. A factor in normal human plasma required for platelet production;
chronic thrombocytopenia due to its deficiency. Blood. 1960; 16: 943-57.
19

Upshaw JD, Jr. Congenital deficiency of a factor in normal plasma thatreverses microangiopathic hemolysis and thrombocytopenia. N Engl J Med. 1978;
298: 1350-2.
20

Rennard S, Abe S. Decreased cold-insoluble globulin in congenital

thrombocytopenia (Upshaw-Schulman syndrome). N Engl J Med. 1979; 300: 368.
33

21

Koizumi S, Miura M, Yamagami M, Horita N, Taniguchi N, Migita S.

Upshaw-Schulman syndrome and fibronectin (cold insoluble globulin). N Engl J
Med. 1981; 305: 1284-5.
22

Goodnough LT, Saito H, Ratnoff OD. Fibronectin levels in congenital

thrombocytopenia: Schulman's syndrome. N Engl J Med. 1982; 306: 938-9.
23

Miura M, Koizumi S, Miyazaki H. Thrombopoietin in Upshaw-Schulman

syndrome. Blood. 1997; 89: 4663-4.
24

Moake JL, Rudy CK, Troll JH, Weinstein MJ, Colannino NM, Azocar J,

Seder RH, Hong SL, Deykin D. Unusually large plasma factor VIII: von Willebrandfactor multimers in chronic relapsing thrombotic thrombocytopenic purpura. N Engl
J Med. 1982; 307: 1432-5.
25

Furlan M, Robles R, Solenthaler M, Wassmer M, Sandoz P, Lämmle B.

Deficient activity of von Willebrand factor-cleaving protease in chronic relapsing
thrombotic thrombocytopenic purpura. Blood. 1997; 89: 3097-103.
26

Kokame K, Matsumoto M, Soejima K, Yagi H, Ishizashi H, Funato M,

Tamai H, Konno M, Kamide K, Kawano Y, Miyata T, Fujimura Y. Mutations andcommon polymorphisms in ADAMTS13 gene responsible for von Willebrandfactor-cleaving protease activity. Proc Natl Acad Sci U S A. 2002; 99: 11902-7.
27

Furlan M, Robles R, Lämmle B. Partial purification and characterization ofa protease from human plasma cleaving von Willebrand factor to fragments produced
by in vivo proteolysis. Blood. 1996; 87: 4223-34.
28

Kato S, Matsumoto M, Matsuyama T, Isonishi A, Hiura H, Fujimura Y.

Novel monoclonal antibody-based enzyme immunoassay for determining plasma
levels of ADAMTS13 activity. Transfusion. 2006; 46: 1444-52.
29

Kokame K, Nobe Y, Kokubo Y, Okayama A, Miyata T. FRETS-VWF73, afirst fluorogenic substrate for ADAMTS13 assay. Br J Haematol. 2005; 129: 93-100.
30

Ferrari S, Mudde GC, Rieger M, Veyradier A, Kremer Hovinga JA,

Scheiflinger F. IgG subclass distribution of anti-ADAMTS13 antibodies in patientswith acquired thrombotic thrombocytopenic purpura. J Thromb Haemost. 2009;
7:1703-10.
31

Kokame K, Kokubo Y, Miyata T. Polymorphisms and mutations of

ADAMTS13 in Japanese population and estimation of the number of patients with
Upshaw-Schulman syndrome. J Thromb Haemost. (in press).
34

32

Plaimauer B, Fuhrmann J, Mohr G, Wernhart W, Bruno K, Ferrari S,

Konetschny C, Antoine G, Rieger M, Scheiflinger F. Modulation of ADAMTS13
secretion and specific activity by a combination of common amino acidplymorphisms and a missense mutation. Blood. 2006; 107: 118-25.
33

Schettert IT, Pereira AC, Lopes NH, Hueb WA, Krieger JE. Association

between ADAMTS13 polymorphisms and risk of cardiovascular events in chronic
coronary disease. Thromb Res. 2010; 125: 61-6.
34

Ruan C, Dai L, Su J, Wang Z. The frequency of P475S polymorphism invon Willebrand factor-cleaving protease in the Chinese population and its relevanceto arterial thrombotic disorders. Thromb Haemost. 2004; 91: 1257-8.
35

Bongers TN, De Maat MP, Dippel DW, Uitterlinden AG, Leebeek FW.

Absence of Pro475Ser polymorphism in ADAMTS-13 in Caucasians. J Thromb
Haemost. 2005; 3: 805.
36

Akiyama M, Kokame K, Miyata T. ADAMTS13 P475S polymorphism

causes a lowered enzymatic activity and urea lability in vitro. J Thromb Haemost.
2008; 6: 1830-2.
37

Yagi H, Konno M, Kinoshita S, Matsumoto M, Ishizashi H, Matsui T,

Titani K, Fujimura Y. Plasma of patients with Upshaw-Schulman syndrome, acongenital deficiency of von Willebrand factor-cleaving protease activity, enhances
the aggregation of normal platelets under high shear stress. Br J Haematol. 2001;
115: 991-7.
38

Konno M, Yoshioka A, Takase T, Imai T. Partial clinical improvement inUpshaw-Schulman syndrome following prostacyclin infusion. Acta Paediatr Jpn.
1995; 37: 97-100.
39

Miura M, Koizumi S, Nakamura K, Ohno T, Tachinami T, Yamagami M,

Taniguchi N, Kinoshita S, Abildgaard CF. Efficacy of several plasma components ina young boy with chronic thrombocytopenia and hemolytic anemia who responds
repeatedly to normal plasma infusions. Am J Hematol. 1984; 17: 307-19.
40

Matsumoto M, Kokame K, Soejima K, Miura M, Hayashi S, Fujii Y, Iwai

A, Ito E, Tsuji Y, Takeda-Shitaka M, Iwadate M, Umeyama H, Yagi H, Ishizashi H,
Banno F, Nakagaki T, Miyata T, Fujimura Y. Molecular characterization of
ADAMTS13 gene mutations in Japanese patients with Upshaw-Schulman syndrome.

35

Blood. 2004; 103: 1305-10.
41

Shinohara T, Miyamura S, Suzuki E, Kobayashi K. Congenital

microangiopathic hemolytic anemia: report of a Japanese girl. Eur J Pediatr. 1982;
138: 191-3.
42

Uchida T, Wada H, Mizutani M, Iwashita M, Ishihara H, Shibano T, Suzuki

M, Matsubara Y, Soejima K, Matsumoto M, Fujimura Y, Ikeda Y, Murata M.
Identification of novel mutations in ADAMTS13 in an adult patient with congenital
thrombotic thrombocytopenic purpura. Blood. 2004; 104: 2081-3.
43

Shibagaki Y, Matsumoto M, Kokame K, Ohba S, Miyata T, Fujimura Y,

Fujita T. Novel compound heterozygote mutations (H234Q/R1206X) of the
ADAMTS13 gene in an adult patient with Upshaw-Schulman syndrome showing
predominant episodes of repeated acute renal failure. Nephrol Dial Transplant. 2006;
21: 1289-92.
44

Kato R, Shinohara A, Sato J. ADAMTS13 deficiency, an important causeof thrombocytopenia during pregnancy. Int J Obstet Anesth. 2009; 18: 73-7.
45

Kokame K, Aoyama Y, Matsumoto M, Fujimura Y, Miyata T. Inherited andde novo mutations of ADAMTS13 in a patient with Upshaw-Schulman syndrome. J
Thromb Haemost. 2008; 6: 213-5.
46

Saitoh H, Murakami H, Mori C. Upshaw-Schulman syndrome in two

siblings. Acta Paediatr Jpn. 1990; 32: 373-6.
47

Hara T, Kitano A, Kajiwara T, Kondo T, Sakai K, Hamasaki Y. Factor VIII

concentrate-responsive thrombocytopenia, hemolytic anemia, and nephropathy.
Evidence that factor VIII:von Willebrand factor is involved in its pathogenesis. Am J
Pediatr Hematol Oncol. 1986; 8: 324-8.
48

Sasahara Y, Kumaki S, Ohashi Y, Minegishi M, Kano H, Bessho F,

Tsuchiya S. Deficient activity of von Willebrand factor-cleaving protease in patientswith Upshaw-Schulman syndrome. Int J Hematol. 2001; 74: 109-14.
49

Kentouche K, Budde U, Furlan M, Scharfe V, Schneppenheim R, Zintl F.

Remission of thrombotic thrombocytopenic purpura in a patient with compound
heterozygous deficiency of von Willebrand factor-cleaving protease by infusion ofsolvent/detergent plasma. Acta Paediatr. 2002; 91: 1056-9.
50

Schneppenheim R, Budde U, Oyen F, Angerhaus D, Aumann V, Drewke E,

Hassenpflug W, Haberle J, Kentouche K, Kohne E, Kurnik K, Mueller-Wiefel D,
36

Obser T, Santer R, Sykora KW. von Willebrand factor cleaving protease and
ADAMTS13 mutations in childhood TTP. Blood. 2003; 101: 1845-50.
51

Antoine G, Zimmermann K, Plaimauer B, Grillowitzer M, Studt JD,

Lämmle B, Scheiflinger F. ADAMTS13 gene defects in two brothers withconstitutional thrombotic thrombocytopenic purpura and normalization of vonWillebrand factor-cleaving protease activity by recombinant human ADAMTS13. Br
J Haematol. 2003; 120: 821-4.
52

Savasan S, Lee SK, Ginsburg D, Tsai HM. ADAMTS13 gene mutation incongenital thrombotic thrombocytopenic purpura with previously reported normal
VWF cleaving protease activity. Blood. 2003; 101: 4449-51.
53

Assink K, Schiphorst R, Allford S, Karpman D, Etzioni A, Brichard B, vande Kar N, Monnens L, van den Heuvel L. Mutation analysis and clinical implicationsof von Willebrand factor-cleaving protease deficiency. Kidney Int. 2003; 63: 1995-9.
54

Pimanda JE, Maekawa A, Wind T, Paxton J, Chesterman CN, Hogg PJ.

Congenital thrombotic thrombocytopenic purpura in association with a mutation in
the second CUB domain of ADAMTS13. Blood. 2004; 103: 627-9.
55

Veyradier A, Lavergne JM, Ribba AS, Obert B, Loirat C, Meyer D, Girma

JP. Ten candidate ADAMTS13 mutations in six French families with congenital
thrombotic thrombocytopenic purpura (Upshaw-Schulman syndrome). J Thromb
Haemost. 2004; 2: 424-9.
56

Licht C, Stapenhorst L, Simon T, Budde U, Schneppenheim R, Hoppe B.

Two novel ADAMTS13 gene mutations in thrombotic thrombocytopenic
purpura/hemolytic-uremic syndrome (TTP/HUS). Kidney Int. 2004; 66: 955-8.
57

Noris M, Bucchioni S, Galbusera M, Donadelli R, Bresin E, Castelletti F,

Caprioli J, Brioschi S, Scheiflinger F, Remuzzi G. Complement factor H mutation infamilial thrombotic thrombocytopenic purpura with ADAMTS13 deficiency andrenal involvement. J Am Soc Nephrol. 2005; 16: 1177-83.
58

Tao Z, Anthony K, Peng Y, Choi H, Nolasco L, Rice L, Moake JL, Dong JF.

Novel ADAMTS-13 mutations in an adult with delayed onset thrombotic
thrombocytopenic purpura. J Thromb Haemost. 2006; 4: 1931-5.
59

Schneppenheim R, Kremer Hovinga JA, Becker T, Budde U, Karpman D,

Brockhaus W, Hrachovinova I, Korczowski B, Oyen F, Rittich S, von Rosen J,
Tjonnfjord GE, Pimanda JE, Wienker TF, Lämmle B. A common origin of the37

4143insA ADAMTS13 mutation. Thromb Haemost. 2006; 96: 3-6.
60

Donadelli R, Banterla F, Galbusera M, Capoferri C, Bucchioni S, Gastoldi

S, Nosari S, Monteferrante G, Ruggeri ZM, Bresin E, Scheiflinger F, Rossi E,
Martinez C, Coppo R, Remuzzi G, Noris M. In-vitro and in-vivo consequences ofmutations in the von Willebrand factor cleaving protease ADAMTS13 in thrombotic
thrombocytopenic purpura. Thromb Haemost. 2006; 96: 454-64.
61

Peyvandi F, Lavoretano S, Palla R, Valsecchi C, Merati G, De Cristofaro R,

Rossi E, Mannuccio Mannucci P. Mechanisms of the interaction between two
ADAMTS13 gene mutations leading to severe deficiency of enzymatic activity. Hum
Mutat. 2006; 27: 330-6.
62Manea M, Kristoffersson A, Tsai HM, Zhou W, Winqvist I, Oldaeus G,

Billstrom R, Bjork P, Holmberg L, Karpman D. ADAMTS13 phenotype in plasma
from normal individuals and patients with thrombotic thrombocytopenic purpura.
Eur J Pediatr. 2007; 166: 249-57.
63

Hommais A, Rayes J, Houllier A, Obert B, Legendre P, Veyradier A, Girma

JP, Ribba AS. Molecular characterization of four ADAMTS13 mutations responsible
for congenital thrombotic thrombocytopenic purpura (Upshaw-Schulman syndrome).
Thromb Haemost. 2007; 98: 593-9.
64

Meyer SC, Jeddi R, Meddeb B, Gouider E, Lammle B, Kremer Hovinga

JA. A first case of congenital TTP on the African continent due to a new homozygous
mutation in the catalytic domain of ADAMTS13. Ann Hematol. 2008; 87: 663-6.
65

Garagiola I, Valsecchi C, Lavoretano S, Oren H, Bohm M, Peyvandi F.

Nonsense-mediated mRNA decay in the ADAMTS13 gene caused by a
29-nucleotide deletion. Haematologica. 2008; 93: 1678-85.
66

Cermakova Z, Hrdlikova R, Sulakova T, Koristka M, Kovarova P,

Hrachovinova I. Thrombotic thrombocytopenic purpura: incidence of congenital
form of disease in north Moravia (region Moravia-Silesia). Prague Med Rep. 2009;
110: 239-44.
67

Ma E, Li Y, Kwok J, Ling S, Pau P, Chau G. ADAMTS13 mutationmal

analysis in Chinese patients wtih chronic relapsing thrombotic thrombocytopenic
purpura. HK J Paediatr. 2006; 11: 22-7.
68Park HW, Oh D, Kim N, Cho HY, Moon KC, Chae JH, Ahn HS, Choi Y,

Cheong HI. Congenital thrombotic thrombocytopenic purpura associated with38

unilateral moyamoya disease. Pediatr Nephrol. 2008; 23: 1555-8.
69

Furlan M, Lämmle B. Aetiology and pathogenesis of thrombotic

thrombocytopenic purpura and haemolytic uraemic syndrome: the role of vonWillebrand factor-cleaving protease. Best Pract Res Clin Haematol. 2001; 14:437-54.
70

Bernardo A, Ball C, Nolasco L, Moake JF, Dong JF. Effects ofinflammatory cytokines on the release and cleavage of the endothelial cell-derived
ultralarge von Willebrand factor multimers under flow. Blood. 2004; 104: 100-6.
71

Motto DG, Chauhan AK, Zhu G, Homeister J, Lamb CB, Desch KC, Zhang

W, Tsai HM, Wagner DD, Ginsburg D. Shigatoxin triggers thrombotic
thrombocytopenic purpura in genetically susceptible ADAMTS13-deficient mice. J
Clin Invest. 2005; 115: 2752-61.
72

Banno F, Kokame K, Okuda T, Honda S, Miyata S, Kato H, Tomiyama Y,

Miyata T. Complete deficiency in ADAMTS13 is prothrombotic, but it alone is not
sufficient to cause thrombotic thrombocytopenic purpura. Blood. 2006; 107: 3161-6.
73

Ishizashi H, Yagi H, Matsumoto M, Soejima K, Nakagaki T, Fujimura Y.

Quantitative Western blot analysis of plasma ADAMTS13 antigen in patients with
Upshaw-Schulman syndrome. Thromb Res. 2007; 120: 381-6.
74

Stirling Y, Woolf L, North WR, Seghatchian MJ, Meade TW. Haemostasis

in normal pregnancy. Thromb Haemost. 1984; 52: 176-82.
75

Sánchez-Luceros A, Farías CE, Amaral MM, Kempfer AC, Votta R,

Marchese C, Salviú MJ, Woods AI, Meschengieser SS, Lazzari MA. von Willebrandfactor-cleaving protease (ADAMTS13) activity in normal non-pregnant women,
pregnant and post-delivery women. Thromb Haemost 2004; 92:1320-6.

39

Figure legend
Figure 1. Geographical distribution of 43 Japanese patients with USS and their
ADAMTS13 gene mutations.
Among 43 USS patients, an ADAMTS13 gene analysis was performed in 39 patients.
Nine of the 39 USS patients had homozygous ADAMTS13 gene mutations, and 29
were the compound heterozygotes, including one patient (USS-W4: patient no 28)
with disease-causing mutation (DCM) on one allele while the other was unidentified.
In the remaining one patient (USS-X5: patient no 29), two single nucleotide
polymorphisms (SNPs), p.P475S and p.G1181R, but not DCMs were identified oneach allele. The p.Q449X mutation localized to the northern part (Tohoku) of
Honshu, c.2259delA to Kyushu, p.C908Y to western Japan, and p.R193W to a
relatively wide area across Japan. Circled numbers indicate the patients shown in
Table 1 and 2.

40

Fig. 1.

Table.1.