TaoMedAI/RareMedData huggingface dataset:
Oculoosteocutaneous syndrome (ORPHA:2713)
A rare multiple congenital anomalies/dysmorphic syndrome characterized by short stature and particularly pronounced shortening of the third to fifth metacarpals and metatarsals, congenital anodontia, sparse hair, dyspigmentation of the skin, hypoplastic nipples and underdeveloped external genitals in females, and multiple ocular abnormalities (such as distichiasis, strabismus, nystagmus, lenticular opacities, and severe myopia, among others). Dysmorphic craniofacial features include brachycephaly, downslanting palpebral fissures, broad nasal root, low-set ears, and small maxilla and prominent mandible. There have been no further descriptions in the literature since 1968.
Oculootodental syndrome (ORPHA:99806)
A contiguous gene syndrome comprising otodental syndrome (characterized by globodontia and sensorineural high-frequency hearing deficit) associated with eye abnormalities including, typically, iris and chorioretinal coloboma, as well as, on occasion, microcornea, microphtalmos, lenticular opacity, lens coloboma and iris pigment epithelial atrophy.
Oculopharyngodistal myopathy (ORPHA:98897)
A rare, genetic neuromuscular disease characterized by progressive external ocular, facial and pharyngeal muscle weakness, leading to variable degrees of ptosis, ophthalmoparesis, facial muscle atrophy, dysarthria and dysphagia, as well as distal muscle weakness and atrophy of lower and upper extremities. Respiratory muscle involvement is common, but sensorineural hearing loss, asymmetrical extremity weakness and severe proximal weakness are rare.
Oculoskeletodental syndrome (ORPHA:557003)
A rare ciliopathy characterized by congenital cataract with secondary glaucoma, developmental delay, short stature, multiple skeletal abnormalities (spinal deformities, limb anomalies, delayed bone age), dental anomalies (oligodontia, enamel defects), dysmorphic facial features (including coarse facies, low hairline, epicanthal folds, flat and broad nasal bridges, and retrognathia), and stroke. Other recurrent manifestations are hearing loss and nephrocalcinosis.
Oculotrichoanal syndrome (ORPHA:2717)
Oculotrichoanal syndrome is a form of rare, multiple congenital anomalies/dysmorphic syndrome characterized by a combination of various nose, eye, gastrointestinal and genitourinary abnormalities. Clinical presentation is variable and often includes bifid and broad nasal tip, aberrant anterior hairline, coloboma, cryptophthalmos or unilateral anophthalmia, anal anomalies, and omphalocele. Intelligence and global development is normal.
Oculotrichodysplasia (ORPHA:2718)
A rare ectodermal dysplasia syndrome characterized by bilateral retinitis pigmentosa, trichodysplasia (generalized hypotrichosis, structural changes), dental anomalies, onychodysplasia, and dry and scaly skin. There have been no further descriptions in the literature since 1988.
Odonto-onycho dysplasia-alopecia syndrome (ORPHA:2722)
Odonto-onycho dysplasia-alopecia syndrome is a rare, genetic ectodermal dysplasia syndrome characterized by almost total alopecia with only sparse, thin, brittle, slow-growing scalp hair, fair and sparse eyebrows and eyelashes, absent axillary and pubic hair, fragile and brittle fingernails, thick and brittle toenails (both with a subungual corneal layer), hypodontia, microdontia, widely spaced teeth with hypoplastic enamel, mild palmoplantar keratosis, café-au-lait spots and areolae anomalies. There have been no further descriptions in the literature since 1985.
Odonto-onycho-dermal dysplasia (ORPHA:2721)
A rare, genetic, ectodermal dysplasia syndrome characterized by dental abnormalities (primarily agenesis of the permanent and deciduous teeth with cone-shaped incisors and canines), onychodysplasia, palmoplantar hyperkeratosis, dry skin and, more variably, hypotrichosis, and sweat gland dysfunction (hyper- or hypohidrosis).
Odonto-tricho-ungual-digito-palmar syndrome (ORPHA:69082)
A rare ectodermal dysplasia syndrome characterized by neonatal teeth, trichodystrophy (with straw-like, discolored and fragile hair), onychodystrophy, and malformation of the hands and feet consisting of simian-like hands with transverse palmar creases and prominent interdigital folds, brachydactyly, and marked shortness of the first metacarpal and metatarsal bones with hypoplasia of the distal phalanges. There have been no further descriptions in the literature since 1997.
Odontochondrodysplasia (ORPHA:166272)
A rare primary bone dysplasia characterized by the association of spondylometaphyseal dysplasia, generalized joint laxity, and dentinogenesis imperfecta. Main skeletal abnormalities comprise short stature, narrow chest, scoliosis, mesomelic limb shortening, and brachydactyly. Radiographic features include severe metaphyseal irregularities of the tubular bones, platyspondyly with coronal clefts, cone-shaped epiphyses of the hands, square iliac wings, and coxa valga. Additional extraskeletal manifestations like pulmonary hypoplasia, cystic renal disease, and non-obstructive hydrocephalus have also been reported.
Odontohypophosphatasia (ORPHA:247685)
A particular form of hypophosphatasia (HPP) characterized by reduced activity of unfractionated serum alkaline phosphatase, premature exfoliation of primary and/or permanent teeth and/or severe dental caries, in the absence of skeletal system abnormalities.
Epidemiology
The prevalence of odonto-HPP is not known. It is thought that odonto-HPP is the most frequent form of HPP because 74% of the cases are heterozygotes.
Clinical description
The main feature of odontohypophosphatasia is premature exfoliation of fully rooted primary teeth and/or severe dental caries. The anterior deciduous teeth are most commonly affected along with the incisors. X-rays reveal reduced alveolar bone, reduced thickness of dentin, and enlarged pulp chambers and root canals. Patients with other forms of HPP often have dental manifestations but these are always associated with skeletal abnormalities and other manifestations.
Etiology
Mutations in the ALPL gene (1p36.12) are known to cause hypophosphatasia. Specific mutations are thought to underlie this phenotype and its variable severity.
Diagnostic methods
Diagnosis is based on clinical presentation, dental panorex and laboratory findings, and can be confirmed by genetic testing.
Differential diagnosis
Other causes for premature exfoliation should be excluded. The presence of bone symptoms (osteomalacia, fractures) distinguish adult HPP from odontohypophosphatasia.
Genetic counseling
Autosomal recessive and autosomal dominant patterns of inheritance are reported in odonto-HPP.
Management and treatment
Management is with observation and supportive measures such as implementation of an oral health program, protection of the existing teeth, and aesthetic and functional restoration of the mouth (with braces or other dental devices).
Prognosis
Loss of teeth may have functional and aesthetic consequences. Overall prognosis is generally good.

                            Last update: 
                            February 2020


                            - Expert reviewer(s): 
                            Dr Severine BACROT  - Dr Etienne MORNET
Odontomatosis-aortae esophagus stenosis syndrome (ORPHA:2724)
Odontoma-dysphagia syndrome is a malformation syndrome, characterized by odontomas (undifferentiated mass of the esophagus) and severe dysphagia.
Epidemiology
Less than ten cases have been reported so far.
Clinical description
Three of the reported patients manifested multiple odontomas. Occasionally, cardiac (stenosis of the intrathoracic descendent aorta, interstitial myocarditis), renal (pyelonephritis) and hepatic (hepatic sclerosis) involvement has been described.
Etiology
Hypertrophy and dysmotility of the esophageal smooth muscles is suggested to have causative role for dysphagia.
Genetic counseling
In several cases, autosomal dominant inheritance has been suspected. Currently, there are no genes associated with this condition.

                            Last update: 
                            July 2009


                            - Expert reviewer(s): 
                            Pr Agnès BLOCH-ZUPAN
Odontomicronychial dysplasia (ORPHA:1811)
A rare, hereditary ectodermal dysplasia syndrome characterized by involvement of teeth and nails - precocious eruption and shedding of deciduous dentition, precocious eruption of secondary dentition with short, rhomboid roots, and short, thin, slow growing nails.
Odontotrichomelic syndrome (ORPHA:2723)
A rare genetic disease characterized by intellectual disability, growth delay, absence deformities of upper and lower limbs, hypotrichosis, hypoplastic nails, abnormal dentition, abnormal auricles, hypoplastic nipples, thyroid enlargement, and abnormalities of tyrosine and/or tryptophane metabolism. Hypogonadism and cleft lip have also been reported. No new cases have been confirmed since 1970.
Off-periods in Parkinson disease not responding to oral treatment (ORPHA:391655)
A rare clinical situation occurring in the context of Parkinson disease characterized by return or worsening of symptoms (including motor and/or non-motor symptoms) under antiparkinsonian therapy. Types of off-periods are Morning Off (experienced before the first dose of the day), Delayed On (occurring more frequently after the first dose of the day or after meals), Wearing Off (end-of-dose deterioration), Sudden Off (sudden transition from on to off), and Dose Failure.
Ogden syndrome (ORPHA:276432)
Ogden syndrome is a rare, genetic progeroid syndrome characterized by a variable phenotype including postnatal growth delay, severe global developmental delay, hypotonia, non-specific dysmorphic facies with aged appearance and cryptorchidism, as well as cardiac arrthymias and skeletal anomalies. Patients typically present with widely opened fontanels, mainly truncal hypotonia, a waddling gait with hypertonia of the extremities, small hands and feet, broad great toes, scoliosis and redundant skin with lack of subcutaneous fat.
Oguchi disease (ORPHA:75382)
Oguchi disease is an autosomal recessive retinal disorder characterized by congenital stationary night blindness (see this term) and the Mizuo-Nakamura phenomenon.
Epidemiology
Oguchi disease is a very rare condition with approximately 50 cases described in the literature to date. It was originally discovered in Japan where the prevalence is the highest but has been found occasionally in European, American, Pakistani and Indian patients.
Clinical description
The disease is characterized by congenital stationary night blindness and the Mizuo-Nakamura phenomenon which is a unique morphological and functional abnormality of the retina that presents with a typical golden-yellow or silver-gray discoloration of the fundus in the presence of light that disappears after dark-adaptation and appears again after the onset of light. Patients have non progressive night blindness since young childhood with normal day vision, but they often claim improvement of light sensitivities when they remain a long time in a dark environment. Eye fundus shows the Mizuo-Nakamura phenomenon as the only fundus feature. A prolonged dark adaptation of 3 hours or more leads to disappearance of the Mizuo-Nakamura phenomenon fundus changes. No evidence of spicules, macular changes or chorioretinal atrophy is observed. Normal visual acuity, normal caliber of retinal blood vessels and usually normal cone response on electroretinogram (ERG) recording suggest retinal dysfunction rather than degeneration.
Etiology
Oguchi disease is caused by mutations in the SAG gene coding for arrestin located on chromosome 2q37(Oguchi type 1) or by mutations in the GRK1 gene that codes for the rhodopsin kinase located on the chromosome 13q34 (Oguchi type 2). Remarkably, some mutations in the SAG gene are associated with Oguchi disease and retinitis pigmentosa (RP) in the same family. Some mutations in SAG lead to RP.
Diagnostic methods
The diagnosis is clinical and is based on the presence of night blindness and the observation of the Mizuo-Nakamura phenomenon by funduscopy and electroretinography (ERG). The clinical diagnosis is confirmed by genetic testing.
Differential diagnosis
The differential diagnosis includes Stargardt disease, RP in female carriers, juvenile retinoschisis, and progressive cone dystrophy (see these terms). All these conditions may have fundus changes but without the classical Mizuo-Nakamura phenomenon.
Genetic counseling
Oguchi disease is an autosomal recessive condition. Brothers and sisters of an affected case have a 25% risk to be also affected.
Management and treatment
To date, there is not a specific treatment for Oguchi disease.
Prognosis
In Oguchi disease the visual prognosis is good in absence of progression of symptoms. Although Oguchi disease is categorized as a stationary condition it can lead to reduced visual acuity or constricted visual fields, especially in older patients.

                            Last update: 
                            December 2011


                            - Expert reviewer(s): 
                            Dr Elena ALLER  - Dr Carmen AYUSO  - Dr José María MILLÁN SALVADOR
Oligoastrocytoma (ORPHA:251656)
Oligoastrocytoma is a type of low-grade glioma with a mixed astrocytoma and oligodendroglioma histology, manifesting with headaches, speech and motor problems, seizures and, in some, subarachnoid haemorrhage.
Oligodendroglial tumor (ORPHA:46484)
Oligodendrogliomas are cerebral tumors that are differentiated from other gliomas on the basis of their unique genetic characteristics and better response to chemotherapy. These tumors are classified according to their grade (low grade oligodendrogliomas: grade II of the WHO classification and anaplastic oligodendrogliomas: grade III of the WHO classification) and according to their pure or mixed histology (oligoastrocytomas).
Epidemiology
Until now, the incidence of these tumors has been largely underestimated. Oligodendrogliomas may represent up to 30% of all adult gliomas. Annual incidence can therefore be estimated at around one new case per 100,000 individuals per year. Prevalence is estimated at 1/300,000.
Clinical description
Low grade tumors are usually diagnosed after a prolonged history of seizures and headaches. Clinical presentation of malignant forms is usually more acute with rapidly progressive neurological deficits and signs of intracranial hypertension (headaches and vomiting). Malignant forms can arise from transformation of a benign tumor several years after its diagnosis. These tumors may develop anywhere in the central nervous system but arise most frequently in the cerebral hemispheres.
Etiology
The etiology is not known but no hereditary forms of oligodendroglioma have been reported. However, specific genetic characteristics, such as loss of chromosomes 1p and 19q, are observed.
Diagnostic methods
MRI may reveal infiltration of the brain parenchyma. Enhancement after contrast injection is indicative of an aggressive and malignant oligodendroglioma.
Differential diagnosis
The differential diagnosis should include low grade astrocytomas (see this term).
Management and treatment
Treatment starts with surgery. Radiotherapy is mandatory for malignant tumors, regardless of the extent of the surgical resection. Chemotherapy is beneficial and is often used during treatment of the initial tumor and for treatment of a recurring malignant oligodendroglioma. In the case of low grade partially resected tumors, chemotherapy now tends to replace radiotherapy as thefirst-line treatment. Management requires a multidisciplinary team with experience in neuro-oncology. The treatment protocol should follow the recommendations resulting from prospective studies.
Prognosis
The prognosis is usually better than that for other gliomas, such as astrocytomas. As a result of combined treatment with surgery, chemotherapy and radiotherapy, survival rates in patients without recurrence are also good, even for patients with malignant (anaplastic) tumors.

                            Last update: 
                            November 2007


                            - Expert reviewer(s): 
                            Dr Jacques GRILL
Oligodendroglioma (ORPHA:251627)
A rare glial tumor characterized by a highly cellular lesion that is diffusly infiltrating at the periphery and consists of evenly-spaced monomorphic cells with the oligodendroglial phenotype. It typically occurs in the supratentorial white matter. Histologically, the cells are uniformly round to oval with round nuclei, delicate chromatin and small nucleoli. Most patients present with seizures.
Oligodontia-cancer predisposition syndrome (ORPHA:300576)
A rare, genetic, odontologic disease characterized by congenital absence of six or more permanent teeth (excluding the third molars) in association with an increased risk for malignancies, ranging from gastrointestinal polyposis to early-onset colorectal cancer and/or breast cancer. Ectodermal dysplasia (manifesting with sparse hair and/or eyebrows) may also be associated.
Oliver syndrome (ORPHA:2920)
Oliver syndrome is a very rare syndrome characterized by intellectual deficit, postaxial polydactyly, and epilepsy.
Epidemiology
To date, seven individuals in three families have been reported.
Clinical description
Facial features are not characteristic except for a prominent jaw. Concordant features in all subjects are postaxial polydactyly, which in four individuals affect also the feet, and intellectual deficit, which is usually severe, with absent or indistinct speech. Seizures are common with onset in the first months of life or in early childhood. Cutaneous syndactyly, camptodactyly and clinodactyly of fingers and brachydactyly and syndactyly of the toes have been recorded.
Genetic counseling
The condition is probably hereditary, and transmitted as an autosomal recessive trait.

                            Last update: 
                            March 2010
Olivopontocerebellar atrophy-deafness syndrome (ORPHA:2732)
Olivopontocerebellar atrophy-deafness syndrome is characterised by infancy-onset olivopontocerebellar atrophy, sensorineural deafness and speech impairment. It has been described in less than 15 children. Most cases were sporadic, but autosomal recessive inheritance was suggested in three cases.
Omodysplasia (ORPHA:2733)
Omodysplasia is a rare skeletal dysplasia characterized by severe limb shortening and facial dysmorphism. Two types of omodysplasia have been described: an autosomal recessive or generalized form (also referred to as micromelic dysplasia with dislocation of radius) marked by severe micromelic dwarfism with predominantly rhizomelic shortening of both the upper and lower limbs, and an autosomal dominant form in which stature is normal and shortening is limited to the upper limbs.
Epidemiology
In total, less than 40 cases of omodysplasia have been described in the literature so far, with the majority of reported cases concerning the autosomal recessive form of the disease.
Clinical description
The facial dysmorphism is characterized by frontal bossing, a depressed nasal bridge with a short nose and a long and prominent philtrum. Decreased mobility of the elbows and knees is also a common feature. Other less frequent manifestations include midline hemangiomas, congenital heart defects, craniosynostosis and cryptorchidism in males.
Etiology
The etiology remains unknown but a paternally-inherited paracentric inversion of 15q13 to q21.3 has been detected in one family.
Diagnostic methods
Diagnosis is based on the clinical and radiological phenotype with major radiological findings including shortening and club-like tapering of the humeri and femora, proximal radioulnar diastasis and proximal radial head dislocation. Although the hands are generally considered to be normal in omodysplasia, short first metacarpals have been reported in the majority of patients with the autosomal dominant form.
Differential diagnosis
The differential diagnosis for the autosomal recessive form should include diastrophic dysplasia, atelosteogenesis and Larsen syndrome (see these terms), whereas the major differential diagnosis for the autosomal dominant form is Robinow syndrome (see this term).
Antenatal diagnosis
For affected families, detection of long bone anomalies by ultrasonography may allow prenatal diagnosis as early as at 13 weeks of gestation.
Genetic counseling
Genetic counseling should be recommended.
Management and treatment
Treatment is symptomatic only, involving mainly orthopedic management for recurrent joint dislocation.
Prognosis
The prognosis is variable.

                            Last update: 
                            November 2008


                            - Expert reviewer(s): 
                            Dr Martine LE MERRER
Omphalocele syndrome, Shprintzen-Goldberg type (ORPHA:3164)
ShprintzenGoldberg omphalocele syndrome is a very rare inherited malformation syndrome characterized by omphalocele, scoliosis, mild dysmorphic features (downslanted palpebral fissures, s-shaped eyelids and thin upper lip), laryngeal and pharyngeal hypoplasia and learning disabilities.
Omphalocele-diaphragmatic hernia-cardiovascular anomalies-radial ray defect syndrome (ORPHA:496693)
A rare multiple congenital anomalies/dysmorphic syndrome characterized by a large omphalocele containing liver and small intestine, diaphragmatic hernia, cardiovascular anomalies (e. g. aortic coarctation), variable limb malformations (including radioulnar synostosis, agenesis of the radius and/or thumb, generalized syndactyly, and numerical reduction of toes), and dysmorphic facial features. Additional reported manifestations are unilateral absence of umbilical artery, intestinal malrotation, hypoplastic ovaries, and unilateral renal agenesis, among others. The condition is mostly fatal in the neonatal period.
Omphalomesenteric cyst (ORPHA:490)
A rare non-syndromic diaphragmatic or abdominal wall malformation, a remnant of omphalomesenteric duct, characterized by cuboidal or columnar epithelium with gastrointestinal differentiation. Patients may be asymptomatic or present with infraumbilical mass, umbilical lesion with secretions, abdominal pain, hernia, abscess, gastrointestinal tract bleeding, intestinal obstruction, and acute abdomen.
Omsk hemorrhagic fever (ORPHA:319266)
Omsk hemorrhagic fever (OHF), caused by Omsk hemorrhagic fever virus (OHFV), is a zoonotic disease characterized by fever, nausea, myalgia and moderately severe hemorrhagic manifestations as well as in some cases meningitis, pneumonia and nephrosis.
Onchocerciasis (ORPHA:2737)
A form of filariasis, caused by the parasitic worm  Onchocerca volvulus, transmitted by the black fly. The infection can either be asymptomatic or manifest as an ocular disease (river blindness) with itchy eyes, erythema, photophobia, onchodermatitis or onchocercal skin disease (classified into acute papular, chronic papular, lichenified, atrophic, and depigmentated) and onchocercomas (over bony prominences). Other classic clinical manifestations are ichthyosis-like lesions (''lizard skin'') and ''hanging groin'', which may be associated with lymphadenopathy.
Onychocytic matricoma (ORPHA:300504)
A rare, benign, nail tumor originating in the nail matrix characterized by localized pachyonychia and variable degrees of pigmentation: pigmented, melanocytic (common, longitudinal melanonychia that may simulate a foreign body) or hypopigmented. Histopathology demonstrates a purely epithelial tumor with endokeratinization in the deep portion and concentrically arranged nests of prekeratogenous and keratogenous cells.
Onychomatricoma (ORPHA:300512)
Onychomatricoma is a rare, benign nail tumor originating in the nail matrix characterized by localized or diffuse thickening of the nail plate, increased transverse or longitudinal overcurvature, a yellow longitudinal band of variable width, swelling of the proximal nail fold, multiple splinter hemorrhages and the presence of honeycomb-like cavities in the distal margin of the nail plate. Nail dystrophy and dorsal pterygium may be associated. Occasionally, a pigmented lesion has been reported.