TaoMedAI/RareMedData huggingface dataset:
Xanthinuria type II (ORPHA:93602)
Type II xanthinuria, a type of classical xanthinuria (see this term), is a rare autosomal recessive disorder of purine metabolism (see this term) characterized by the deficiency of both xanthine dehydrogenase and aldehyde oxidase, leading to the formation of urinary xanthine urolithiasis and leading, in some patients, to kidney failure. Other less common manifestations include arthropathy, myopathy and duodenal ulcer, while some patients remain asymptomatic.
Xanthoma disseminatum (ORPHA:158003)
A rare, systemic disease characterized by normolipidemic mucocutaneous xanthomatosis with histiocytic cells proliferation and secondary deposition of lipid in the dermis. Clinically, multiple, grouped, coalescent, yellowish red to brown papulonodular lesions in the skin and mucous membranes are present. Less often internal organs are affected, in particular pituitary gland and/or hypothalamus. Patients present with characteristic mucocutaneous lesions, diabetes insipidus, dysphagia, dyspnea, hoarseness of voice, and blurred vision.
Xeroderma pigmentosum variant (ORPHA:90342)
Xeroderma pigmentosum variant is a milder subtype of xeroderma pigmentosum (XP; see this term), a rare genetic photodermatosis characterized by severe sun sensitivity and an increased risk of skin cancer.
Epidemiology
It is observed in approximately 20% of XP patients and approximately 50 cases have been reported in the literature.
Clinical description
It is often diagnosed in the late teens or early 20s. Patients present with skin lesions, generally at the sun-exposed parts of the body which develop into skin cancer at about 20-30 years of age with a 1,000 times higher frequency than that of the general population. No neurological manifestations are observed.
Etiology
The disease is due to mutations in the POLH gene (XPV) (6p21.1-p12) encoding the error-prone DNA-polymerase eta (pol-eta) which performs trans-lesion synthesis past ultraviolet (UV) photoproducts.
Genetic counseling
Transmission is autosomal recessive.

                            Last update: 
                            May 2011


                            - Expert reviewer(s): 
                            Dr Hiva FASSIHI
Xeroderma pigmentosum-Cockayne syndrome complex (ORPHA:220295)
Xeroderma pigmentosum/Cockayne syndrome complex (XP/CS complex) is characterized by the cutaneous features of xeroderma pigmentosum (XP) (see this term) together with the systemic and neurological features of Cockayne syndrome (CS; see this term).
Epidemiology
Less than 30 cases have been described to date.
Clinical description
The disease manifests during infancy. Patients present with cutaneous UV-sensitive lesions that generally develop into skin cancer, and also develop characteristic CS manifestations such as microcephaly, hydrocephalus, cachexia, premature aging, dwarfism, skin atrophy, arteriosclerosis, progressive hearing loss, cognitive deficit, spasticity, ataxia, pigmentary retinopathy and optic atrophy. In contrast to the neurological abnormalities of XP which are predominantly secondary to neuronal degeneration, in XP/CS complex, dysmyelination typical of CS is observed.
Etiology
Affected individuals have mutations in one of three XP genes: ERCC3 (2q21), ERCC2 (19q13.3), or ERCC5 (13q22-q34). Recently, one patient with XP/CS complex and additional features of Fanconi anemia (see this term) was reported with a mutation in the ERCC4 gene (16p13.3).
Genetic counseling
Transmission is autosomal recessive and genetic counseling is possible.

                            Last update: 
                            March 2014


                            - Expert reviewer(s): 
                            Dr Hiva FASSIHI
XK aprosencephaly syndrome (ORPHA:3469)
A rare syndromic type of cerebral malformation characterized by aprosencephaly (absence of telencephalon and diencephalon), oculo-facial anomalies (i.e. ocular hypotelorism or cyclopia, malformatiobsence of nasal structures, cleft lip), preaxial limb defects (i.e. hypoplastic hands, absent halluces) and various other anomalies including ambiguous genitalia, imperforate anus, and vertebral anomalies. The syndrome is thought to have an autosomal recessive mode of inheritance.
XMEN (ORPHA:317476)
X-linked immunodeficiency with magnesium defect, Epstein-Barr virus infection and neoplasia is a rare combined T and B cell immunodeficiency characterized by recurrent sinopulmonary and viral infections, persistent elevated Epstein-Barr virus (EBV) viremia and increased susceptibility to EBV-associated B-cell lymphoproliferative disorders. Immunological analyses show normal lymphocyte count or mild to moderate lymphopenia, inverted CD4:CD8 T-cell ratio and hypogammaglobulinemias.
Xp21 deletion syndrome (ORPHA:261476)
A rare chromosomal anomaly characterized by complex glycerol kinase deficiency, congenital adrenal hypoplasia, intellectual disability and/or Duchenne muscular dystrophy that usually affect males. The clinical features depend on the deletion size and the number and type of involved genes.
Xp22.13p22.2 duplication syndrome (ORPHA:284180)
A rare syndromic intellectual disability characterized by developmental delay and intellectual disability, learning and behavioral problems, short stature, thin and sparse hair, mild dysmorphic features, tapering fingers and later onset of scoliosis, obesity and cardiovascular problems (cardiomegaly and cardiomyopathy). Females have normal intelligence.
Xp22.3 microdeletion syndrome (ORPHA:1643)
Xp22.3 microdeletion syndrome is a microdeletion syndrome resulting from a partial deletion of the chromosome X. Phenotype is highly variable (depending on length of deletion), but is mainly characterized by X linked ichthyosis, mild-moderate intellectual deficit, Kallmann syndrome, short stature, chondrodysplasia punctata and ocular albinism. Epilepsy, attention deficit-hyperactivity disorder, autism and difficulties with social communication can be associated.
Xq12-q13.3 duplication syndrome (ORPHA:314389)
Xq12-q13.3 duplication syndrome is a rare chromosomal anomaly syndrome, resulting from the partial duplication of the long arm of chromosome X, characterized by global developmental delay, autistic behavior, microcephaly and facial dysmorphism (including down-slanting palpebral fissures, depressed nasal bridge, anteverted nares, long philtrum, down-slanting corners of the mouth). Seizures have also been reported in some patients.
Xq21 microdeletion syndrome (ORPHA:1435)
An X-linked retinal dystrophy characterized by choroideremia, causing in affected males progressive nyctalopia and eventual central blindness. Obesity, moderate intellectual disability and congenital mixed (sensorineural and conductive) deafness are also observed. Female carriers show typical retinal changes indicative of the choroideremia carrier state.
Xq25 microduplication syndrome (ORPHA:521258)
A rare, X-linked, multiple congenital anomalies/dysmorphic malformation-intellectual disability syndrome characterized by developmental delay, mild to moderate intellectual disability, speech disturbance, behavioral problems (such as anxiety, hyperactivity, and aggressiveness) and mild facial dysmorphism (including facial hypotonia, thin arched eyebrows, ectropion, epicanthus, malar flatness, thick vermillion of the lips and prognathia). Additional variable manifestations include short stature, skeletal and genital anomalies, seizures, and autism spectrum disorders. Brain imaging may reveal cerebellar vermis hypoplasia, thin corpus callosum, and enlarged subarachnoid spaces.
Xq27.3q28 duplication syndrome (ORPHA:261483)
Xq27.3q28 duplication syndrome is a recently described syndrome characterized by short stature, hypogonadism, developmental delay and facial dysmorphism.
Epidemiology
It has been clinically and molecularly characterized in 3 male members from the same family.
Clinical description
Facial features include deep-set eyes, bulbous nasal tip and thin lips. Hypogonadism is due to primary gonadal failure. Patients also had some features which are probably caused by testosterone deficiency such as a high-pitched voice, sparse body hair and small hands and feet. Carrier females present with a short stature and early menopause.
Etiology
This syndrome is caused by an Xq27.3q28 interstitial duplication encompassing the FMR1 and AFF2  genes but not the MECP2 gene. This duplication was characterized by comparative genomic hybridization (CGH) microarray and fluorescence in situ hybridization (FISH).
Genetic counseling
Transmission is X-linked.

                            Last update: 
                            July 2011


                            - Expert reviewer(s): 
                            Dr Nicole MORICHON-DELVALLEZ
XY type gonadal dysgenesis-associated anomalies syndrome (ORPHA:1770)
A rare syndrome with 46,XY difference of sex development characterized by mild developmental delay and streak gonads associated with short stature, cardiac, renal, musculoskeletal, and ectodermal abnormalities (the latter including scalp defects and unusual hair whorls), and dysmorphic facial features (such as preauricular pits, short columella, and small nares). There have been no further descriptions in the literature since 1980.
XYLT1-CDG (ORPHA:370930)
A rare congenital disorder of glycosylation characterized by moderate intellectual disability, short stature, mild skeletal changes and distinctive facial features with coarse face, synophyrs and deep nasolabial ridges. Skeletal features include broad ribs, stocky long bones, short femoral necks with coxa valga, clinodactyly and broad thumbs.
Yellow nail syndrome (ORPHA:662)
A rare, syndromic nail anomaly disease characterized by the variable triad of characteristic yellow nails, chronic respiratory manifestations, and primary lymphedema.
Epidemiology
Prevalence and incidence rates are not known, but Yellow nail syndrome (YNS) is considered a rare condition. To date, approximately 400 cases have been reported, mainly as single case reports. The disorder affects males and females equally.
Clinical description
Most cases of YNS are of late onset, after 50 years of age, but the disease has also occasionally been observed in neonates and children. Patients generally complain of slowed or arrested nail growth: the nails become thickened and opaque, with yellowish or green discoloration. The cuticles are absent and the proximal nail fold swollen. Increased transverse curvature is another feature, which may lead to nail plate shedding. Both fingernails and toenails are affected, but severity may vary. Only 1/3 of the patients with nail changes have associated lymphedema and respiratory tract involvement. Nail changes may precede the development of lymphedema or respiratory manifestations by years. Lymphedema is the most consistent associated finding and usually affects the lower limbs. Respiratory conditions include cough, bronchitis, tracheobronchitis, bronchiectasis, chronic sinusitis, chronic respiratory infections, and pleural effusions. YNS may exceptionally be a paraneoplastic disorder (lung cancer).
Etiology
The etiology of YNS has not been elucidated. Impaired lymphatic drainage not due to anatomical abnormalities, but rather to a functional disorder, appears to have a central role.
Diagnostic methods
Nail changes in YNS are pathognomonic and the presence of typical nail alterations is an absolute requirement for the diagnosis. This is because the three main signs (i.e. nail changes, respiratory disorders, and lymphedema) may not be present all at once in the patient.
Differential diagnosis
The most important nail differential diagnoses include chronic paronychia, which shares absence of the cuticle and nail thickening and discoloration, and onychomycosis of the toenails, which produces thickening and onycholysis. Onychogryphosis and acquired pachyonychia should also be considered.
Management and treatment
Spontaneous improvement in nail signs is reported in up to 30% of cases. Oral α‐tocopherol (vitamin E) at high doses, 600 to 1200 international units (IU) daily has been reported to be effective in about half of patients.
Prognosis
Some patients recover fully, but the respiratory condition and the associated symptoms are often chronic. Serious lymphedema and respiratory complications may affect quality of life and periodic follow-up is mandatory. Patients with YNS present several comorbidities other than the respiratory ones, possibly due to their older age, therefore they tipically have a lower life expectancy when compared to the general population.

                            Last update: 
                            June 2019


                            - Expert reviewer(s): 
                            Pr Bianca Maria PIRACCINI
Yolk sac tumor (ORPHA:876)
A rare germ cell tumor characterized by multiple patterns reflecting endodermal extraembryonal differentiation (secondary yolk sac and allantois) or endodermal somatic tissues (intestine, liver, and mesenchyme). The tumors most commonly occur in the second or third decade of life. They are typically located in the gonads, occasionally also in other regions. Patients present with a pelvic mass and/or abdominal pain (females) or an often painless, unilateral testicular mass (males). Elevated serum alpha fetoprotein is a common laboratory finding.
Young adult-onset distal hereditary motor neuropathy (ORPHA:314485)
Young adult-onset distal hereditary motor neuropathy is a rare autosomal recessive distal hereditary motor neuropathy characterized by slowly progressive muscular weakness, hypotonia and atrophy of the lower limbs, more pronounced distally, leading to paralysis, and loss of tendon reflexes. Additional features may include pes cavus and mild dysphonia. The upper limbs are relatively spared.
Young syndrome (ORPHA:3471)
A rare respiratory disease characterized by recurrent sinopulmonary infections and bronchiectasis predominantly in the lower lung fields, as well as azoospermia with reduced fertility, due to production of thick, viscous mucus which causes mild airflow obstruction in the respiratory tract and obstruction of sperm transport in the genital tract. Patients commonly present in adulthood. Sweat gland and pancreatic function are normal. The cause of the syndrome is unknown, however mercury exposure had been proposed as a potential cause.
Yunis-Varon syndrome (ORPHA:3472)
A rare, genetic, multiple congenital malformation syndrome, characterized by cleidocranial dysplasia (wide fontanelles, calvaria dysostosis, absent or hypoplastic clavicles), absent thumbs and halluces, hypoplastic distal and medial phalanges of fingers, pelvic dysplasia with hip dislocations. Dysmorphic features include sparse scalp hair, protruding eyes, low-set ears, anteverted nares, midfacial hypoplasia, tented upper lip, high arched palate, and micrognathia. Brain malformations are frequently associated. From birth, affected individuals tend to be significantly hypotonic and present with global developmental delay, and respiratory, feeding and swallowing difficulties.
Zebra body myopathy (ORPHA:97240)
Zebra body myopathy is a benign congenital myopathy, characterised by congenital hypotonia and weakness. Prevalence is unknown. Less than ten patients have been described so far. Muscle biopsy shows zebra bodies and other myopathic changes. Mutations of the alpha-skeletal actin (ACTA1) gene may be involved.
Zechi-Ceide syndrome (ORPHA:217017)
A rare, genetic, multiple congenital anomalies/dysmorphic syndrome characterized by occipital atretic cephalocele associated with a specific facial dysmorphism (consisting of prominent forehead, narrow palpebral fissures, midface deficiency, narrow, malformed ears, broad nose and nasal root, grooved nasal tip and columella, laterally angulated, hypoplastic nares, short philtrum, thin upper lip, clift lip/palate, severe oligodontia, prominent chin) and large feet with sandal gap. Intellectual disability, developmental delay and hypoplastic finger and toenails have also been reported.
Zellweger-like syndrome without peroxisomal anomalies (ORPHA:50812)
A rare mitochondrial disorder characterized by facial dysmorphism similar to that seen in Zellweger syndrome (see this term), such as frontal bossing, high forehead, upslanting palpebral fissures, hypoplastic supraorbital ridges, and epicanthal folds, and in addition, pale skin, profound hypotonia, developmental delay, and minor metabolic anomalies. No peroxysomal defects, however, have been reported. Transmission is thought to be autosomal recessive.
Zika virus disease (ORPHA:448237)
Zika virus disease is an emerging Aedes mosquito-born virus disease characterized by a clinical course that may be asymptomatic or mild with fever, conjunctivitis, muscle and joint pain, headache, exanthema, but may also be associated with severe neurological (meningitis, meningoencephalitis and myelitis) and auto-immune (Guillain-Barre syndrome) complications, as well as a potential increase of birth defects (microcephaly) if the infection occurs during pregnancy.
Zinc-responsive necrolytic acral erythema (ORPHA:439196)
A rare skin disease characterized initially by erythematous patches with superficial necrosis, at later stages by hyperkeratotic plaques with a rim of dusky erythema, of exclusively acral distribution with a predilection for the lower extremities, and universal association with hepatitis C virus infection. Patients typically experience pruritus or pain. Serum zinc levels may or may not be decreased, although oral zinc supplementation often improves the condition.
Zygomycosis (ORPHA:73263)
A rare mycosis caused by ubiquitous, opportunistic fungi of the order Mucorales, characterized by tissue infarction and necrosis due to invasion of the vasculature by hyphae. The spectrum of clinical manifestations depends on the route of infection and includes rhinocerebral, pulmonary, cutaneous, gastrointestinal, renal, and disseminated forms. The disease is usually rapidly progressive and associated with high mortality.
Åland Islands eye disease (ORPHA:178333)
An X-linked recessive retinal disease characterized by fundus hypopigmentation, decrased visual acuity, nystagmus, astigmatism, progressive axial myopia, defective dark adaptation and protanopia.
Epidemiology
AIED is a very rare disease originally reported in a family from Aland islands in the Bothnia sea. Some other cases from the Baltic area and other origins have been reported but the clinical features of these cases overlap with X-linked incomplete congenital stationary night blindness (CSNB2; see this term).
Clinical description
AIED is characterized by hypopigmented eye fundus, foveal dysplasia with no foveal reflex that leads to decreased visual acuity, progressive axial myopia, latent nystagmus, astigmatism, night blindness and protan color vision defect. The hypopigmentation is most pronounced in the posterior pole and in the peripapillary region. Female carriers may show slight disturbances of color discrimination and subtle nystagmus.
Etiology
AIED is caused by mutations in the CACNA1F gene. Some mutations in CACNAF1 are associated with CSNB2 suggesting allelism of the two disorders.
Diagnostic methods
Patients with a clinical suspicion of AIED should undergo a complete ophthalmologic examination including funduscopy, visual acuity, refraction defects, electroretinogramm (ERG) and color vision test. Mutation screening of CACNA1F gene including the presence of large deletions in the gene can help the clinical diagnosis.
Differential diagnosis
Differential diagnosis includes X-linked ocular albinism (OA1; see this term) and CSNB2. The lack of misrouting of optic nerve axons excludes OA1 whereas CSNB2 is apparently stationary with a normal fovea and, usually, no color defects.
Genetic counseling
AIED is an X-linked disorder, with a carrier female having a 50% risk of transmitting the mutation to her offspring. Carrier testing for at-risk female relatives is possible. Genetic counseling of the family is recommended.
Management and treatment
No treatment is available except for correction of the myopia.
Prognosis
Except for progression of axial myopia, the disease presents a stationary course.

                            Last update: 
                            December 2011


                            - Expert reviewer(s): 
                            Dr Carmen AYUSO  - Dr Teresa JAIJO  - Dr José María MILLÁN SALVADOR
Neonatal diabetes mellitus (ORPHA:224)
Neonatal diabetes mellitus presents as hyperglycemia, failure to thrive and, in some cases, dehydration and ketoacidosis which may be severe with coma, in a child within the first months of life.
Epidemiology
Transient (TNDM) and Permanent (PNDM) neonatal diabetes are rare conditions occurring in 1:300,000-400,000 live births.

Clinical description
TNDM infants develop diabetes in the first few weeks of life but go into remission in a few months, with possible relapse to a permanent diabetes state usually around adolescence or as adults. The pancreatic dysfunction may be maintained throughout life, with relapse initiated at times of metabolic stress such as puberty or pregnancy. Patients with TNDM are more likely to have intrauterine growth retardation and less likely to develop ketoacidosis than patients with PNDM. In TNDM, patients are younger at the diagnosis of diabetes and have lower initial insulin requirements. In PNDM, insulin secretory failure occurs in the late fetal or early post-natal period and does not go into remission. Considerable overlap occurs between the two groups, so that TNDM cannot be distinguished from PNDM based on clinical features. Very early onset diabetes mellitus seems to be unrelated to autoimmunity in most instances.

Etiology
A number of conditions are associated with PNDM, some of which have been elucidated at the molecular level. Among these, the very recently elucidated mutations in the KCNJ11 and ABCC8 genes, encoding the Kir6.2 and SUR1 subunit of the pancreatic KATP channel involved in regulation of insulin secretion, account for one third to half of the PNDM cases.

Diagnostic methods
Molecular analysis of chromosome 6 anomalies, and the KCNJ11 and ABCC8 genes encoding Kir6.2 and SUR1, provides a tool to identify TNDM from PNDM in the neonatal period. This analysis also has potentially important therapeutic consequences leading to transfer some patients, those with mutations in KCNJ11 and ABCC8 genes, from insulin therapy to sulfonylureas.

Differential diagnosis

Antenatal diagnosis

Genetic counseling

Management and treatment
Recurrent diabetes is common in patients with 'transient'' neonatal diabetes mellitus and, consequently, prolonged follow-up is imperative. Insulin pump may offer an interesting therapeutic tool in this age group in experienced hands.

Prognosis