Browse A-Z | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program

Browse A-Z | Genetic and Rare Diseases Information Center (GARD) – an NCATS Program





Browse the GARD list of rare diseases and related terms to find topics of interest to you. This list includes the main name for each condition, as well as alternate names. Inclusion on this list does not serve as official recognition by the NIH that a disease is rare. Some conditions that are not considered rare are on this list and are labeled accordingly.Read more about which diseases are included on the GARD website.



O 1/1

• O Donnell Pappas syndrome
• OA1 - See Ocular albinism type 1
• OAFNS - See Oculoauriculofrontonasal syndrome
• OAK - See Optic atrophy 1
• OASD - See Albinism ocular late onset sensorineural deafness
• Oat cell lung cancer - See Small cell lung cancer
• OAT deficiency - See Gyrate atrophy of choroid and retina
• OAV dysplasia - See Goldenhar disease
• OAVD - See Oculo-auriculo-vertebral spectrum
• OAVS - See Goldenhar disease
• OAVS with radial defect - See Microsomia hemifacial radial defects
• Obesity due to congenital leptin deficiency - See Obesity due to congenital leptin deficiency
• Obesity due to congenital leptin deficiency
• Obesity due to pro-opiomelanocortin deficiency - See Proopiomelanocortin deficiency
• Obesity, early-onset, adrenal insufficiency, and red hair - See Proopiomelanocortin deficiency
• Obesity, mental retardation, body asymmetry, and muscle weakness - See Camera Marugo Cohen syndrome
• Obesity, morbid, nonsyndromic 1 - See Obesity due to congenital leptin deficiency
• Oblique facial clefts - See Oculomaxillofacial dysostosis
• Obliterative bronchiolitis - See Bronchiolitis obliterans
• Obstructive disease of the pulmonary veins - See Pulmonary venoocclusive disease
• OCA - See Oculocutaneous albinism
• OCA1 - See Oculocutaneous albinism type 1
• OCA1A - See Oculocutaneous albinism type 1
• OCA1B - See Oculocutaneous albinism type 1B
• OCA2 - See Oculocutaneous albinism type 2
• OCA3 - See Oculocutaneous albinism type 3
• OCC Syndrome - See Oculocerebrocutaneous syndrome
• Occipital atretic cephalocele, unusual facies and large feet - See Zechi Ceide syndrome
• Occipital horn syndrome
• Occlusive infantile arteriopathy - See Arterial calcification of infancy
• Occlusive peripheral vascular disease - See Buerger disease
• OCCS - See Oculocerebrocutaneous syndrome
• Occult spina bifida - See Spina bifida occulta - not a rare disease
• Occult spinal dysraphism - See Tethered cord syndrome
• Occult spinal dysraphism sequence - See Tethered cord syndrome
• Ochoa syndrome
• Ochronosis
• Ochronosis, acquired - See Exogenous ochronosis
• Ochronosis, hereditary - See Alkaptonuria
• OCRL - See Lowe oculocerebrorenal syndrome
• OCRL1 - See Lowe oculocerebrorenal syndrome
• OCTD - See MASS phenotype
• Ocular albinism type 1
• Ocular albinism with sensorineural deafness - See Albinism ocular late onset sensorineural deafness
• Ocular cicatricial pemphigoid
• Ocular colobomas, ichthyosis, brain malformations and endocrine abnormalities
• Ocular hypotelorism, submucosal cleft palate, and hypospadias - See Hypotelorism cleft palate hypospadias
• Ocular MD - See Ocular Muscular Dystrophy
• Ocular melanoma
• Ocular motility disorders - See Motor neuro-ophthalmic disorders
• Ocular motility disorders
• Ocular Muscular Dystrophy
• Ocular neuromyotonia
• Ocular Neuropathic Pain Syndrome - See Corneal neuropathic disease
• Ocular nonnephropathic cystinosis - See Cystinosis, ocular nonnephropathic
• Ocular toxoplasmosis
• Oculo digital syndrome
• Oculo skeletal renal syndrome
• Oculoauriculofrontonasal dysplasia - See Oculoauriculofrontonasal syndrome
• Oculoauriculofrontonasal syndrome
• Oculoauriculovertebral dysplasia - See Goldenhar disease
• Oculo-Auriculo-Vertebral Dysplasia - See Oculo-auriculo-vertebral spectrum
• Oculo-auriculo-vertebral spectrum
• Oculoauriculovertebral spectrum with radial defect - See Microsomia hemifacial radial defects
• Oculoauriculovertebral syndrome - See Goldenhar disease
• Oculo-cerebral dysplasia
• Oculocerebral hypopigmentation syndrome - See Oculocerebral syndrome with hypopigmentation
• Oculocerebral hypopigmentation syndrome type Preus
• Oculocerebral syndrome with hypopigmentation
• Oculocerebrocutaneous syndrome
• Oculo-cerebro-cutaneous syndrome - See Oculocerebrocutaneous syndrome
• Oculocerebrorenal syndrome - See Lowe oculocerebrorenal syndrome
• Oculocraniosomatic syndrome - See Kearns-Sayre syndrome
• Oculocutaneous albinism
• Oculocutaneous albinism type 1
• Oculocutaneous albinism type 1A - See Oculocutaneous albinism type 1
• Oculocutaneous albinism type 1B
• Oculocutaneous albinism type 2
• Oculocutaneous albinism type 3
• Oculocutaneous albinism tyrosinase positive - See Oculocutaneous albinism type 2
• Oculocutaneous albinism, immunodeficiency, hematological disorders, and minor anomalies - See Kotzot-Richter syndrome
• Oculocutaneous albinism, minimal pigment type - See Albinism, minimal pigment type
• Oculocutaneous albinism, tyrosinase negative - See Oculocutaneous albinism type 1
• Oculocutaneous tyrosinemia - See Tyrosinemia type 2
• Oculodentodigital dysplasia
• Oculo-dento-digital dysplasia - See Oculodentodigital dysplasia
• Oculodentodigital dysplasia dominant
• Oculodentodigital syndrome - See Oculodentodigital dysplasia
• Oculo-dento-digital syndrome - See Oculodentodigital dysplasia
• Oculodentoosseous dysplasia recessive
• Oculodigitoesophagoduodenal syndrome - See Feingold syndrome
• Oculoectodermal syndrome
• Oculo-ectodermal syndrome - See Oculoectodermal syndrome
• Oculofaciocardiodental syndrome
• Oculogastrointestinal muscular dystrophy - See Familial visceral myopathy with external ophthalmoplegia
• Oculogastrointestinal muscular dystrophy - See Mitochondrial neurogastrointestinal encephalopathy syndrome
• Oculomaxillofacial dysostosis
• Oculomaxillofacial dysplasia with oblique facial clefts - See Oculomaxillofacial dysostosis
• Oculomelic amyoplasia - See Distal arthrogryposis type 5
• Oculomotor apraxia Cogan type
• Oculootoradial syndrome - See IVIC syndrome
• Oculopharyngeal distal myopathy - See Oculopharyngodistal myopathy
• Oculopharyngeal muscular dystrophy
• Oculopharyngodistal myopathy
• Oculorenocerebellar syndrome
• Oculosympathetic Palsy - See Horner's syndrome
• Oculotrichoanal syndrome - See Manitoba oculotrichoanal syndrome
• ODCD - See Spondylometaphyseal dysplasia with dentinogenesis imperfecta
• ODD syndrome - See Oculodentodigital dysplasia
• ODDD - See Oculodentodigital dysplasia
• ODED syndrome - See Feingold syndrome
• ODOD recessive - See Oculodentoosseous dysplasia recessive
• O'Doherty syndrome - See Ermine phenotype
• Odonto onycho dysplasia with alopecia
• Odontochondrodysplasia - See Spondylometaphyseal dysplasia with dentinogenesis imperfecta
• Odontogenic myxoma
• Odontoma
• Odontoma dysphagia syndrome
• Odontomatosis (multiple odontomas) with dysphagia - See Odontoma dysphagia syndrome
• Odontomicronychial dysplasia
• Odonto-micronychial dysplasia - See Odontomicronychial dysplasia
• Odontoonychodermal dysplasia
• Odontotrichomelic hypohidrotic dysplasia - See Odontotrichomelic syndrome
• Odontotrichomelic syndrome
• OEIS complex - See Omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects complex
• OFCD syndrome - See Oculofaciocardiodental syndrome
• OFD - See Orofaciodigital syndromes
• OFD syndrome 1 - See Orofaciodigital syndrome 1
• OFD syndrome 10 - See Orofaciodigital syndrome 10
• OFD syndrome 11 - See Orofaciodigital syndrome 11
• OFD syndrome 13 - See Orofaciodigital syndrome 13
• OFD syndrome 2 - See Orofaciodigital syndrome 2
• OFD syndrome 3 - See Orofaciodigital syndrome 3
• OFD syndrome 4 - See Orofaciodigital syndrome 4
• OFD syndrome 5 - See Orofaciodigital syndrome 5
• OFD syndrome 8 - See Orofaciodigital syndrome 8
• OFD syndrome 9 - See Orofaciodigital syndrome 9
• OFD syndrome with tibial defects - See Orofaciodigital syndrome 4
• OFD1 - See Orofaciodigital syndrome 1
• OFD10 - See Orofaciodigital syndrome 10
• OFD11 - See Orofaciodigital syndrome 11
• OFD12 - See Orofaciodigital syndrome 12
• OFD13 - See Orofaciodigital syndrome 13
• OFD14 - See Orofaciodigital syndrome 14
• OFD2 - See Orofaciodigital syndrome 2
• OFD3 - See Orofaciodigital syndrome 3
• OFD4 - See Orofaciodigital syndrome 4
• OFD5 - See Orofaciodigital syndrome 5
• OFD6 - See Orofaciodigital syndrome 6
• OFD8 - See Orofaciodigital syndrome 8
• OFD9 - See Orofaciodigital syndrome 9
• OFDS 1 - See Orofaciodigital syndrome 1
• OFDS 10 - See Orofaciodigital syndrome 10
• OFDS 11 - See Orofaciodigital syndrome 11
• OFDS 12 - See Orofaciodigital syndrome 12
• OFDS 13 - See Orofaciodigital syndrome 13
• OFDS 2 - See Orofaciodigital syndrome 2
• OFDS 3 - See Orofaciodigital syndrome 3
• OFDS 4 - See Orofaciodigital syndrome 4
• OFDS 5 - See Orofaciodigital syndrome 5
• OFDS 8 - See Orofaciodigital syndrome 8
• OFDS 9 - See Orofaciodigital syndrome 9
• Ofuji disease - See Eosinophilic pustular folliculitis
• Ofuji's disease - See Eosinophilic pustular folliculitis
• OGD - See Osteoglophonic dysplasia
• Ogilvie syndrome
• Ogilvie's syndrome - See Ogilvie syndrome
• OGIMD - See Mitochondrial neurogastrointestinal encephalopathy syndrome
• Oguchi disease
• OHAHA syndrome - See Infantile onset spinocerebellar ataxia
• Ohara disease - See Tularemia
• Ohdo Blepharophimosis syndrome - See Blepharophimosis intellectual disability syndromes
• Ohdo syndrome - See Blepharophimosis intellectual disability syndromes
• OHF - See Omsk hemorrhagic fever
• OHS - See Occipital horn syndrome
• OI - See Osteogenesis imperfecta
• OI 9 - See Osteogenesis imperfecta type IX
• OI type 1 - See Osteogenesis imperfecta type I
• OI type 10 - See Osteogenesis imperfecta
• OI type 11 - Another name for Osteogenesis imperfecta type XI
• OI type 2 - See Osteogenesis imperfecta type II
• OI type 3 - See Osteogenesis imperfecta type III
• OI type 4 - See Osteogenesis imperfecta type IV
• OI type 5 - See Osteogenesis imperfecta type V
• OI type 6 - See Osteogenesis imperfecta type VI
• OI type 7 - See Osteogenesis imperfecta type VII
• OI type III - See Osteogenesis imperfecta type III
• OI type IV - See Osteogenesis imperfecta type IV
• Oi type IX - See Osteogenesis imperfecta type IX
• OI type V - See Osteogenesis imperfecta type V
• OI type VI - See Osteogenesis imperfecta type VI
• OI type VII - See Osteogenesis imperfecta type VII
• OI type VIII - See Osteogenesis imperfecta type VIII
• OI type X - See Osteogenesis imperfecta
• OI type XI - Another name for Osteogenesis imperfecta type XI
• OI with calcification in interosseous membranes - See Osteogenesis imperfecta type V
• OI11 - Another name for Osteogenesis imperfecta type XI
• OI6 - See Osteogenesis imperfecta type VI
• OI8 - See Osteogenesis imperfecta type VIII
• Okamoto syndrome
• Okihiro syndrome - See Duane-radial ray syndrome
• OKT deficiency - See Gyrate atrophy of choroid and retina
• Old Age Pemphigus - See Bullous pemphigoid
• Olfacto-genital pathological sequence - See Kallmann syndrome
• Olfactory neuroblastoma
• Oligoarthritis, juvenile - See Pauciarticular onset juvenile idiopathic arthritis
• Oligoarticular onset juvenile idiopathic arthritis - See Pauciarticular onset juvenile idiopathic arthritis
• Oligoastrocytoma
• Oligodactyly tetramelic postaxial
• Oligodendroglioma
• Oligohydramnios sequence - See Potter sequence
• Oligomeganephronia - See Oligomeganephronic renal hypoplasia
• Oligomeganephronic renal hypoplasia
• Oligophrenia phenylpyruvica - See Phenylketonuria
• Oligophrenin-1 syndrome - See OPHN1 syndrome
• Oliver McFarlane syndrome - See Trichomegaly with intellectual disability, dwarfism and pigmentary degeneration of retina
• Oliver syndrome
• Olivopontocerebellar atrophy
• Olivopontocerebellar atrophy 1 - See Spinocerebellar ataxia 1
• Olivopontocerebellar atrophy 2 - See Spinocerebellar ataxia 2
• Olivopontocerebellar atrophy 3 - See Spinocerebellar ataxia 7
• Olivopontocerebellar atrophy 4 - See Spinocerebellar ataxia 1
• Olivopontocerebellar atrophy deafness
• Olivopontocerebellar atrophy Holguin type - See Spinocerebellar ataxia 2
• Olivopontocerebellar hypoplasia fetal-onset - See Pontocerebellar hypoplasia type 5
• Ollier disease
• Olmsted syndrome
• OMA syndrome - See Opsoclonus-myoclonus syndrome
• Omenn syndrome
• OMM syndrome - See Pillay syndrome
• OMOD1 - See Omodysplasia 1
• OMOD2 - See Omodysplasia 2
• Omodysplasia 1
• Omodysplasia 2
• Omodysplasia autosomal recessive - See Omodysplasia 1
• Omodysplasia generalized form - See Omodysplasia 1
• Omodysplasia, autosomal dominant - See Omodysplasia 2
• Omphalocele - cloacal exstrophy - imperforate anus - spinal defect - See Omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects complex
• Omphalocele cleft palate syndrome lethal
• Omphalocele syndrome, Shprintzen-Goldberg type - See Shprintzen omphalocele syndrome
• Omphalocele with hypoplasia of pharynx and larynx, learning disability, dysmorphic facies, and scoliosis - SeeShprintzen omphalocele syndrome
• Omphalocele, diaphragmatic hernia, and radial ray defects - See Gershoni-Baruch syndrome
• Omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects - See Omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects complex
• Omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects complex
• Omphalocele, laryngeal and pharyngeal hypoplasia, learning disabilities, dysmorphic facies and spinal anomalies - SeeShprintzen omphalocele syndrome
• Omphalocele-cloacal exstrophy-imperforate anus-spinal defect syndrome - See Omphalocele, exstrophy of the cloaca, imperforate anus, and spinal defects complex
• Omphalomesenteric cyst
• OMS - See Opsoclonus-myoclonus syndrome
• Omsk hemorrhagic fever
• Onat syndrome - See Subaortic stenosis short stature syndrome
• Onchocerciasis
• Oncocytic cardiomyopathy - See Infantile histiocytoid cardiomyopathy
• Oncocytoma kidney - See Renal oncocytoma
• Oncocytoma renal - See Renal oncocytoma
• Oncogenic hypophosphatemic osteomalacia - See Oncogenic osteomalacia
• Oncogenic osteomalacia
• Ondine curse (formerly) - See Congenital central hypoventilation syndrome
• Ondine's curse (formerly) - See Congenital central hypoventilation syndrome
• Onion whorl disease - See Localized hypertrophic neuropathy
• Onset of senility in the early teens, atrophic skin, hypogonadism, retinal and vascular sclerosis - See Ruvalcaba Churesigaew Myhre syndrome
• Onychocytic matricoma
• Onychodystrophy totalis - See Twenty-nail dystrophy
• Onychodystrophy-anonychia
• Onychoosteodysplasia - See Nail-patella syndrome
• Onychotrichodysplasia and neutropenia
• OOCH - See Osteoporosis oculocutaneous hypopigmentation syndrome
• OOCH syndrome - See Osteoporosis oculocutaneous hypopigmentation syndrome
• OORS - See IVIC syndrome
• OPA1 - See Optic atrophy 1
• OPA2 - See Optic atrophy 2
• OPA3 - See Autosomal dominant optic atrophy and cataract
• OPA3 defect
• OPA3, autosomal dominant - See Autosomal dominant optic atrophy and cataract
• OPA6 - See Optic atrophy 6
• OPCA - See Olivopontocerebellar atrophy
• OPCA III - See Spinocerebellar ataxia 7
• OPCA with macular degeneration and external ophthalmoplegia - See Spinocerebellar ataxia 7
• OPCA with retinal degeneration - See Spinocerebellar ataxia 7
• OPCA1 - See Spinocerebellar ataxia 1
• OPCA3 - See Spinocerebellar ataxia 7
• OPCA4 - See Spinocerebellar ataxia 1
• OPD 2 syndrome - See Oto-palato-digital syndrome type 2
• OPD syndrome - See Oto-palato-digital syndrome type 1
• OPD syndrome 1 - See Oto-palato-digital syndrome type 1
• OPD1 - See Oto-palato-digital syndrome type 1
• OPDM - See Oculopharyngodistal myopathy
• Open spine - See Spina bifida
• OPHN1 Deficiency - See OPHN1 syndrome
• OPHN1- related XLID - See OPHN1 syndrome
• OPHN1 syndrome
• OPHN1 XLMR - See OPHN1 syndrome
• OPHN1 XLMR, X-linked intellectual disability - See OPHN1 syndrome
• Ophthalmoacromelic syndrome - See Anophthalmos with limb anomalies
• Ophthalmo-mandibulo-melic dysplasia - See Pillay syndrome
• Ophthalmoplegia - hypotonia - ataxia - hypoacusis - athetosis - See Infantile onset spinocerebellar ataxia
• Ophthalmoplegia plus syndrome - See Kearns-Sayre syndrome
• Ophthalmoplegia, hypotonia, ataxia, hypacusis, and athetosis - See Infantile onset spinocerebellar ataxia
• Ophthalmoplegia, pigmentary degeneration of retina, and cardiomyopathy - See Kearns-Sayre syndrome
• Ophthalmoplegia, progressive external, with ragged red fibers - See Kearns-Sayre syndrome
• Ophthalmoplegia-hypotonia-ataxia-hypoacusis-athetosis syndrome - See Infantile onset spinocerebellar ataxia
• Ophthalmoplegia-intellectual disability-lingua scrotalis syndrome - See Levic Stefanovic Nikolic syndrome
• Ophthalmoplegic MD - See Ophthalmoplegic Muscular dystrophy
• Ophthalmoplegic Muscular dystrophy
• Opisthorchiasis
• Opitz BBBG syndrome - See Opitz G/BBB syndrome
• Opitz G/BBB syndrome
• Opitz Mollica Sorge syndrome - See Acrofacial dysostosis Catania type
• Opitz trigonocephaly syndrome - See C syndrome
• Opitz trigonocephaly-like syndrome - See Bohring-Opitz syndrome
• Opitz-Frias syndrome - See Opitz G/BBB syndrome
• Opitz-G syndrome, type 2 - See Opitz G/BBB syndrome
• Opitz-Kaveggia syndrome - See FG syndrome
• OPLL - See Ossification of the posterior longitudinal ligament of the spine - not a rare disease
• OPMD - See Oculopharyngeal muscular dystrophy
• Oppenheim disease - See Amyotonia congenita
• Oppenheim's disease - See Amyotonia congenita
• Oppenheim's dystonia - See DYT-TOR1A
• OPPG - See Osteoporosis-pseudoglioma syndrome
• OPS - See Osteoporosis-pseudoglioma syndrome
• Opsismodysplasia
• Opsoclonus myoclonus syndrome - See Opsoclonus-myoclonus syndrome
• Opsoclonus-myoclonus syndrome
• Opsoclonus-myoclonus-ataxia syndrome - See Opsoclonus-myoclonus syndrome
• OPTA1 - See Osteopetrosis autosomal dominant type 1
• OPTA2 - See Osteopetrosis autosomal dominant type 2
• OPTB1 - See Osteopetrosis autosomal recessive 1
• OPTB2 - See Osteopetrosis autosomal recessive 2
• OPTB3 - See Osteopetrosis autosomal recessive 3
• OPTB4 - See Osteopetrosis autosomal recessive 4
• OPTB5 - See Osteopetrosis autosomal recessive 5
• OPTB6 - See Osteopetrosis autosomal recessive 6
• OPTB7 - See Osteopetrosis autosomal recessive 7
• Opthalmic icthyosis
• Opthalmomandibulomelic dysplasia
• Opthalmoplegia myalgia tubular aggregates
• Opthalmoplegia progressive external scoliosis
• Optic atrophy - deafness- polyneuropathy - myopathy - See Autosomal dominant optic atrophy plus syndrome
• Optic atrophy 1
• Optic atrophy 1 and deafness
• Optic atrophy 2
• Optic atrophy 3 - See OPA3 defect
• Optic atrophy 3 - See Autosomal dominant optic atrophy and cataract
• Optic atrophy 3 with cataract - See Autosomal dominant optic atrophy and cataract
• Optic atrophy 5
• Optic atrophy 6
• Optic atrophy in early childhood, associated with ataxia, spasticity, mental retardation, and posterior column sensory loss - See Behr syndrome
• Optic atrophy infantile with chorea and spastic paraplegia - See OPA3 defect
• Optic atrophy opthalmoplegia ptosis deafness myopia
• Optic atrophy plus syndrome - See OPA3 defect
• Optic atrophy polyneuropathy deafness
• Optic atrophy type 1 - See Optic atrophy 1
• OPTIC ATROPHY WITH OR WITHOUT DEAFNESS, OPHTHALMOPLEGIA, MYOPATHY, ATAXIA, AND NEUROPATHY - SeeAutosomal dominant optic atrophy plus syndrome
• Optic atrophy, cataract, and neurologic disorder - See Autosomal dominant optic atrophy and cataract
• Optic atrophy, congenital or early infantile, autosomal recessive - See Optic atrophy 6
• Optic atrophy, hearing loss, and peripheral neuropathy, autosomal recessive - See Optic atrophy polyneuropathy deafness
• Optic atrophy, infantile hereditary, Behr complicated form of - See Behr syndrome
• Optic atrophy, juvenile - See Optic atrophy 1
• Optic atrophy, Kjer type - See Optic atrophy 1
• Optic atrophy, Leber type - See Leber hereditary optic neuropathy
• Optic atrophy, neural deafness, and distal neurogenic amyotrophy - See Optic atrophy polyneuropathy deafness
• Optic atrophy, non-Leber type, with early onset - See Optic atrophy 2
• Optic atrophy, polyneuropathy, and deafness - See Charcot-Marie-Tooth disease
• Optic atrophy, sensorineural hearing loss and polyneuropathy - See Charcot-Marie-Tooth disease
• Optic atrophy, X-linked - See Optic atrophy 2
• Optic atrophy-deafness-polyneuropathy-myopathy syndrome - See Autosomal dominant optic atrophy plus syndrome
• Optic coloboma, vesicoureteral reflux, and renal anomalies - See Renal coloboma syndrome
• Optic nerve coloboma - See Coloboma of optic nerve
• Optic nerve coloboma with renal disease - See Renal coloboma syndrome
• Optic nerve head pits, bilateral congenital - See Coloboma of optic nerve
• Optic nerve hypoplasia, familial bilateral
• Optic neuritis
• Optic pathway glioma
• Opticoacoustic nerve atrophy dementia
• Opticoacustic nerve atrophy with dementia - See Jensen syndrome
• Oral and digital anomalies with ichthyosis - See Ichthyosis tapered fingers midline groove up
• Oral cancer
• Oral facial digital syndrome 1 - See Orofaciodigital syndrome 1
• Oral facial digital syndrome 10 - See Orofaciodigital syndrome 10
• Oral facial digital syndrome 11 - See Orofaciodigital syndrome 11
• Oral facial digital syndrome 12 - See Orofaciodigital syndrome 12
• Oral facial digital syndrome 13 - See Orofaciodigital syndrome 13
• Oral facial digital syndrome 2 - See Orofaciodigital syndrome 2
• Oral facial digital syndrome 3 - See Orofaciodigital syndrome 3
• Oral facial digital syndrome 4 - See Orofaciodigital syndrome 4
• Oral facial digital syndrome 5 - See Orofaciodigital syndrome 5
• Oral facial digital syndrome 8 - See Orofaciodigital syndrome 8
• Oral facial digital syndrome 9 - See Orofaciodigital syndrome 9
• Oral facial digital syndrome type 1 - See Orofaciodigital syndrome 1
• Oral facial digital syndrome type 10 - See Orofaciodigital syndrome 10
• Oral facial digital syndrome type 11 - See Orofaciodigital syndrome 11
• Oral facial digital syndrome type 12 - See Orofaciodigital syndrome 12
• Oral facial digital syndrome type 13 - See Orofaciodigital syndrome 13
• Oral facial digital syndrome type 2 - See Orofaciodigital syndrome 2
• Oral facial digital syndrome type 3 - See Orofaciodigital syndrome 3
• Oral facial digital syndrome type 4 - See Orofaciodigital syndrome 4
• Oral facial digital syndrome type 5 - See Orofaciodigital syndrome 5
• Oral facial digital syndrome type 8 - See Orofaciodigital syndrome 8
• Oral facial digital syndrome type 9 - See Orofaciodigital syndrome 9
• Oral facial digital syndromes - See Orofaciodigital syndromes
• Oral facial dystonia - See Meige syndrome
• Oral gangrene - See Noma
• Oral leukoplakia
• Oral lichen planus - not a rare disease
• Oral lichenoid lesions - See Oral lichen planus - not a rare disease
• Oral pharyngeal disorders
• Oral squamous cell carcinoma
• Oral submucous fibrosis
• Oral-facial-digital syndrome - See Orofaciodigital syndromes
• Oral-facial-digital syndrome 1 - See Orofaciodigital syndrome 1
• Oral-facial-digital syndrome 10 - See Orofaciodigital syndrome 10
• Oral-facial-digital syndrome 12 - See Orofaciodigital syndrome 12
• Oral-facial-digital syndrome 13 - See Orofaciodigital syndrome 13
• Oral-facial-digital syndrome 5 - See Orofaciodigital syndrome 5
• Oral-facial-digital syndrome type 1 - See Orofaciodigital syndrome 1
• Oral-facial-digital syndrome type 11 - See Orofaciodigital syndrome 11
• Oral-facial-digital syndrome type 12 - See Orofaciodigital syndrome 12
• Oral-facial-digital syndrome type 13 - See Orofaciodigital syndrome 13
• Oral-facial-digital syndrome type 14 - See Orofaciodigital syndrome 14
• Oral-facial-digital syndrome type 2 - See Orofaciodigital syndrome 2
• Oral-facial-digital syndrome type 3 - See Orofaciodigital syndrome 3
• Oral-facial-digital syndrome type 4 - See Orofaciodigital syndrome 4
• Oral-facial-digital syndrome type 6 - See Orofaciodigital syndrome 6
• Oral-facial-digital syndrome type 8 - See Orofaciodigital syndrome 8
• Oral-facial-digital syndrome type 9 - See Orofaciodigital syndrome 9
• Oral-facial-digital syndrome with fibular aplasia - See Orofaciodigital syndrome 10
• Oral-facial-digital syndrome with hypoplastic epiglottis - See Orofaciodigital syndrome 8
• Oral-facial-digital syndrome with retinal abnormalities - See Orofaciodigital syndrome 9
• Oral-facial-digital syndrome with skeletal anomalies - See Orofaciodigital syndrome 11
• Oral-facial-digital syndrome XIII - See Orofaciodigital syndrome 13
• Oral-facial-digital syndromes - See Orofaciodigital syndromes
• Orbital cyst with cerebral and focal dermal malformations - See Oculocerebrocutaneous syndrome
• Orbital lymphangioma
• Orbital lymphoma
• Orbital melanoma
• Orbital varix
• Orbital venous varix - See Orbital varix
• ORC syndrome - See Oculorenocerebellar syndrome
• Orchidoblastoma - See Testicular yolk sac tumor
• Oregon type tyrosinemia - See Tyrosinemia type 2
• Organic acidemia
• Organic mood syndrome
• Organizing pneumonia - See Bronchiolitis obliterans organizing pneumonia
• Organoid nevus phakomatosis - See Linear nevus sebaceous syndrome
• Organoid nevus with sebaceous differentiation, a speckled-lentiginous nevus, and other associated anomalies - SeePhacomatosis pigmentokeratotica
• Ormond disease - See Retroperitoneal fibrosis
• Ormond's disease - See Retroperitoneal fibrosis
• Ornithine aminotransferase deficiency - See Gyrate atrophy of choroid and retina
• Ornithine carbamoyltransferase deficiency - See Ornithine transcarbamylase deficiency
• Ornithine ketoacid aminotransferase deficiency - See Gyrate atrophy of choroid and retina
• Ornithine transcarbamylase deficiency
• Ornithine translocase deficiency - See Ornithine translocase deficiency syndrome
• Ornithine translocase deficiency syndrome
• Ornithinemia
• Ornithosis - See Psittacosis
• Oroacral syndrome - See Oro-mandibular-limb hypogenesis syndrome
• Orocraniodigital syndrome - See Juberg-Hayward syndrome
• Orofacial cleft 11 - See Microphthalmia syndromic 6
• Oro-facial gangrene - See Noma
• Orofacial Granulomatosis
• Oro-facial noma - See Noma
• Orofaciodigital syndrome - See Orofaciodigital syndromes
• Orofaciodigital syndrome 1
• Orofaciodigital syndrome 10
• Orofaciodigital syndrome 11
• Orofaciodigital syndrome 12
• Orofaciodigital syndrome 13
• Orofaciodigital syndrome 14
• Orofaciodigital syndrome 2
• Orofaciodigital syndrome 3
• Orofaciodigital syndrome 4
• Orofaciodigital syndrome 5
• Orofaciodigital syndrome 6
• Orofaciodigital syndrome 8
• Orofaciodigital syndrome 9
• Orofaciodigital syndrome I - See Orofaciodigital syndrome 1
• Orofaciodigital syndrome II - See Orofaciodigital syndrome 2
• Orofaciodigital syndrome III - See Orofaciodigital syndrome 3
• Orofaciodigital syndrome IV - See Orofaciodigital syndrome 4
• Orofaciodigital syndrome IX - See Orofaciodigital syndrome 9
• Orofaciodigital syndrome type 12 - See Orofaciodigital syndrome 12
• Orofaciodigital syndrome type 13 - See Orofaciodigital syndrome 13
• Orofaciodigital syndrome type 14 - See Orofaciodigital syndrome 14
• Orofaciodigital syndrome type 6 - See Orofaciodigital syndrome 6
• Orofaciodigital syndrome type 8 - See Orofaciodigital syndrome 8
• Orofaciodigital syndrome type Figuera - See Orofaciodigital syndrome 10
• Orofaciodigital syndrome V - See Orofaciodigital syndrome 5
• Orofaciodigital syndrome VIII - See Orofaciodigital syndrome 8
• Orofaciodigital syndrome with fibular aplasia - See Orofaciodigital syndrome 10
• Orofaciodigital syndrome with retinal abnormalities - See Orofaciodigital syndrome 9
• Orofaciodigital syndrome with tibial dysplasia - See Orofaciodigital syndrome 4
• Orofaciodigital syndrome X - See Orofaciodigital syndrome 10
• Orofaciodigital syndrome XI - See Orofaciodigital syndrome 11
• Orofaciodigital syndrome XII - See Orofaciodigital syndrome 12
• Orofaciodigital syndrome XIII - See Orofaciodigital syndrome 13
• Orofaciodigital syndromes
• Oro-mandibular-limb hypogenesis syndrome
• Oropharyngeal cancer, adult
• Oropharyngeal cancer, childhood
• Oropharyngeal infection leading to secondary septic thrombophlebitis of the internal jugular vein - See Lemierre syndrome
• Orotate phosphoribosyltransferase and omp decarboxylase deficiency - See Orotic aciduria type 1
• Orotic aciduria II (formerly) - See Orotic aciduria type 1
• Orotic aciduria type 1
• Oroticaciduria 1 - See Orotic aciduria type 1
• Orotidylic pyrophosphorylase and orotidylic decarboxylase deficiency - See Orotic aciduria type 1
• Orstavik Lindemann Solberg syndrome
• Orthostatic hypotension (a symptom) - See Pure autonomic failure
• Orthostatic intolerance due to NET deficiency
• Orthostatic tremor, primary - See Primary orthostatic tremor
• ORW disease - See Hereditary hemorrhagic telangiectasia
• ORW2 - See Hereditary hemorrhagic telangiectasia type 2
• ORW3 - See Hereditary hemorrhagic telangiectasia type 3
• osASD - See Ostium secundum atrial septal defect
• OSCS - See Osteopathia striata cranial sclerosis
• Osebold-Remondini syndrome - See Brachydactyly type A6
• Oslam syndrome
• Osler Weber Rendu syndrome - See Hereditary hemorrhagic telangiectasia
• Osler Weber Rendu syndrome type 2 - See Hereditary hemorrhagic telangiectasia type 2
• Osler Weber Rendu syndrome type 3 - See Hereditary hemorrhagic telangiectasia type 3
• Osler-Rendu-Weber disease - See Hereditary hemorrhagic telangiectasia
• OSMED - See OSMED Syndrome
• OSMED Syndrome
• OSMF - See Oral submucous fibrosis
• Ossicular Malformations, familial
• Ossification of the posterior longitudinal ligament of the spine - not a rare disease
• Ossified ear cartilages with mental deficiency, muscle wasting, and bony changes - See Primrose syndrome
• Ossifying fibroma - See Osteofibrous dysplasia
• Osteitis deformans - See Paget disease of bone - not a rare disease
• Osteoarthropathy of fingers familial
• Osteoarthropathy, premature degenerative, of hip - See Beukes familial hip dysplasia
• Osteochondritis deformans - See Legg-Calve-Perthes disease
• Osteochondritis dissecans
• Osteochondritis dissecans, short stature, and early-onset osteoarthritis - See Familial osteochondritis dissecans
• Osteochondritis of tarsal/metatarsal bone - See Kohler disease
• Osteochondrodysplasia with rhizomelia, platyspondyly, callosal agenesis, thrombocytopenia, hydrocephalus, and hypertension - See Faye-Petersen-Ward-Carey syndrome
• Osteochondrodysplasias - See Skeletal dysplasias - not a rare disease
• Osteochondroma
• Osteochondromuscular dystrophy - See Schwartz Jampel syndrome
• Osteochondrosis
• Osteochondrosis deformans tibiae - See Blount disease
• Osteochondrosis deformans tibiae, familial infantile type - See Blount disease
• Osteochondrosis of the metatarsal head, usually the second - See Freiberg's disease
• Osteochondrosis of the tarsal bone - See Kohler disease
• Osteoclastoma - See Giant cell tumor of bone
• Osteocraniosplenic syndrome - See Gracile bone dysplasia
• Osteocraniostenosis - See Gracile bone dysplasia
• Osteodysgenesis, multisynostotic with fractures - See Antley Bixler syndrome
• Osteodysplasia familial Anderson type
• Osteodysplastic primordial dwarfism type 2 - See Microcephalic osteodysplastic primordial dwarfism type 2
• Osteodysplastic primordial dwarfism type I - See Microcephalic osteodysplastic primordial dwarfism type 1
• Osteodysplasty of Melnick and Needles - See Melnick-Needles syndrome
• Osteodysplasty precocious of Danks Mayne and Kozlowski
• Osteofibrous dysplasia
• Osteogenesis imperfecta
• Osteogenesis imperfecta congenita - See Osteogenesis imperfecta type II
• Osteogenesis imperfecta congenita perinatal lethal form - See Osteogenesis imperfecta type II
• Osteogenesis imperfecta Levin type
• Osteogenesis imperfecta ocular form - See Osteoporosis-pseudoglioma syndrome
• Osteogenesis imperfecta retinopathy seizures intellectual deficit - See Al Gazali Sabrinathan Nair syndrome
• Osteogenesis imperfecta sillence type II/III without abnormality of type I collagen - See Osteogenesis imperfecta type IX
• Osteogenesis imperfecta tarda - See Osteogenesis imperfecta type I
• Osteogenesis imperfecta type - See Osteogenesis imperfecta type VI
• Osteogenesis imperfecta type 10 - See Osteogenesis imperfecta
• Osteogenesis imperfecta type 11 - Another name for Osteogenesis imperfecta type XI
• Osteogenesis imperfecta type 2 - See Osteogenesis imperfecta type II
• Osteogenesis imperfecta type 8 - See Osteogenesis imperfecta type VIII
• Osteogenesis imperfecta type 9 - See Osteogenesis imperfecta type IX
• Osteogenesis imperfecta type I
• Osteogenesis imperfecta type II
• Osteogenesis imperfecta type III
• Osteogenesis imperfecta type IV
• Osteogenesis imperfecta type IX
• Osteogenesis imperfecta type V
• Osteogenesis imperfecta type VI
• Osteogenesis imperfecta type VII
• Osteogenesis imperfecta type VIII
• Osteogenesis imperfecta type X - See Osteogenesis imperfecta
• Osteogenesis imperfecta type XI
• Osteogenesis imperfecta with blue sclerae - See Osteogenesis imperfecta type I
• Osteogenesis imperfecta with congenital joint contractures - See Bruck syndrome 1
• Osteogenesis imperfecta with normal sclerae - See Osteogenesis imperfecta type IV
• Osteogenesis imperfecta with unusual skeletal lesions - See Osteogenesis imperfecta Levin type
• Osteogenesis imperfecta, progressively deforming with normal sclerae - See Osteogenesis imperfecta type III
• Osteogenic sarcoma - See Osteosarcoma
• Osteoglophonic dwarfism - See Osteoglophonic dysplasia
• Osteoglophonic dysplasia
• Osteolysis massive - See Gorham's disease
• Osteolysis syndrome recessive
• Osteolysis, distal, with short stature, mental retardation, and characteristic facial appearance - See Osteolysis syndrome recessive
• Osteolysis, familial expansile - See Polyostotic osteolytic dysplasia, hereditary expansile
• Osteolysis, hereditary multicentric - See Torg Winchester syndrome
• Osteomalacia
• Osteomesopyknosis
• Osteomyelitis
• Osteo-Onychodysplasia - See Nail-patella syndrome
• Osteopathia condensans disseminata - See Buschke Ollendorff syndrome
• Osteopathia condensans disseminata - See Osteopoikilosis
• Osteopathia striata - cranial sclerosis - See Osteopathia striata cranial sclerosis
• Osteopathia striata associated with familial dermopathy and white forelock - See Osteopathia striata with pigmentary dermopathy including white forelock
• Osteopathia striata cranial sclerosis
• Osteopathia striata with pigmentary dermopathy including white forelock
• Osteopathia striata-cranial sclerosis syndrome - See Osteopathia striata cranial sclerosis
• Osteopenia and sparse hair
• Osteopenia mental retardation sparse hair - See Osteopenia and sparse hair
• Osteopetroses - See Osteopetrosis
• Osteopetrosis
• Osteopetrosis and infantile neuroaxonal dystrophy
• Osteopetrosis autosomal dominant type 1
• Osteopetrosis autosomal dominant type 2
• Osteopetrosis autosomal recessive 1
• Osteopetrosis autosomal recessive 2
• Osteopetrosis autosomal recessive 3
• Osteopetrosis autosomal recessive 4
• Osteopetrosis autosomal recessive 5
• Osteopetrosis autosomal recessive 6
• Osteopetrosis autosomal recessive 7
• Osteopetrosis autosomal recessive intermediate form - See Osteopetrosis autosomal recessive 6
• Osteopetrosis infantile malignant 1 - See Osteopetrosis autosomal recessive 1
• Osteopetrosis infantile malignant 2 - See Osteopetrosis autosomal recessive 4
• Osteopetrosis infantile malignant 3 - See Osteopetrosis autosomal recessive 5
• Osteopetrosis osteoclast-poor - See Osteopetrosis autosomal recessive 2
• Osteopetrosis osteoclast-poor with hypogammaglobulinemia - See Osteopetrosis autosomal recessive 7
• Osteopetrosis with renal tubular acidosis - See Osteopetrosis autosomal recessive 3
• Osteopoikilosis
• Osteopoikilosis and dacryocystitis
• Osteopoikilosis-short stature-intellectual disability syndrome - See 12q14 microdeletion syndrome
• Osteoporosis oculocutaneous hypopigmentation syndrome
• Osteoporosis pseudoglioma syndrome - See Osteoporosis-pseudoglioma syndrome
• Osteoporosis, juvenile - See Juvenile osteoporosis
• Osteoporosis-pseudoglioma syndrome
• Osteopsathyrosis - See Osteogenesis imperfecta
• Osteosarcoma
• Osteosarcoma, limb anomalies (clinodactyly, absence of digital ray in foot, bilateral radioulnar synostosis) and macrocytosis without anemia - See Oslam syndrome
• Osteosarcoma, limb anomalies, and erythroid macrocytosis with megaloblastic marrow - See Oslam syndrome
• Osteosclerosis abnormalities of nervous system and meninges
• Osteosclerosis fragilis - See Osteopetrosis
• Osteosclerosis of the skull and enlarged mandible - See Van Buchem disease type 2
• Osteosclerosis with ichthyosis and POF - See Osteosclerosis with ichthyosis and premature ovarian failure
• Osteosclerosis with ichthyosis and premature ovarian failure
• Osteosclerosis, autosomal dominant - See Worth type autosomal dominant osteosclerosis
• Osteosclerosis, autosomal dominant, Worth type - See Worth type autosomal dominant osteosclerosis
• Ostertag type amyloidosis - See Amyloidosis familial visceral
• Ostium primum ASD - See Atrial septal defect ostium primum
• Ostium secundum ASD - See Ostium secundum atrial septal defect
• Ostium secundum atrial septal defect
• OT - See Primary orthostatic tremor
• OTC deficiency - See Ornithine transcarbamylase deficiency
• OTCD - See Ornithine transcarbamylase deficiency
• Otodental dysplasia
• Otofaciocervical syndrome
• Otoonychoperoneal syndrome
• Oto-onycho-peroneal syndrome - See Otoonychoperoneal syndrome
• Oto-Palatal-digital syndrome
• Otopalatodigital syndrome type 1 - See Oto-palato-digital syndrome type 1
• Oto-palato-digital syndrome type 1
• Otopalatodigital syndrome type 2 - See Oto-palato-digital syndrome type 2
• Oto-palato-digital syndrome type 2
• Otosclerosis, familial
• Otospondylomegaepiphyseal dysplasia - See OSMED Syndrome
• Oto-Spondylo-Mega-Epiphyseal Dysplasia - See OSMED Syndrome
• Otto syndrome - See Arthrogryposis multiplex congenita
• Otulipenia
• OTX2-related eye disorders - See Microphthalmia syndromic 5
• Oudtshoorn skin - See Keratolytic winter erythema
• Ouvrier Billson syndrome
• Ovarian Brenner tumor - See Brenner tumor of ovary
• Ovarian cancer
• Ovarian cancer, epithelial - See Ovarian epithelial cancer
• Ovarian carcinoma - See Ovarian cancer
• Ovarian carcinoma, childhood - See Childhood ovarian cancer
• Ovarian carcinosarcoma
• Ovarian dysgenesis with sensorineural deafness - See Perrault syndrome
• Ovarian epithelial cancer
• Ovarian epithelial carcinoma - See Ovarian epithelial cancer
• Ovarian germ cell tumor
• Ovarian gynandroblastoma - See Gynandroblastoma
• Ovarian insufficiency due to FSH resistance
• Ovarian insufficiency, familial
• Ovarian low malignant potential tumor
• Ovarian malignant mixed epithelial mesenchymal tumor - See Ovarian carcinosarcoma
• Ovarian malignant mixed Müllerian tumor - See Ovarian carcinosarcoma
• Ovarian remnant syndrome
• Ovarian sex cord tumor with annular tubules
• Ovarian sex cord-stromal tumor - See Ovarian sex cord tumor with annular tubules
• Ovarian small cell carcinoma
• Overgrowth - craniosynostosis - arthrogryposis - See Richieri-Costa Guion-Almeida Cohen syndrome
• Overgrowth radial ray defect arthrogryposis
• Overgrowth syndrome with accelerated skeletal maturation, unusual facies, and camptodactyly - See Weaver syndrome
• Overhydrated hereditary stomatocytosis - See Stomatocytosis I
• Overlap connective tissue disease - See MASS phenotype
• Ovoid neutrophil nuclei, developmental delay, epilepsy and skeletal abnormalities - See Pelger-Huet anomaly
• Ovoid pupils - See Egg shaped pupils
• Oxalosis 1 - See Primary hyperoxaluria type 1
• Oxalosis 2 - See Primary hyperoxaluria type 2
• Oxoglutaricaciduria - See Alpha-ketoglutarate dehydrogenase deficiency
• Oxoprolinase deficiency - See Glutathione synthetase deficiency
• Oxoprolinuria due to 5-oxoprolinase deficiency - See 5-oxoprolinase deficiency