Explore the signs and symptoms, genetic cause, and inheritance pattern of various health conditions.
- OA, see Ocular albinism
- OA, see Osteoarthritis
- OAS, see Ophthalmo-acromelic syndrome
- OAT deficiency, see Gyrate atrophy of the choroid and retina
- OAV complex, see Craniofacial microsomia
- OAVS, see Craniofacial microsomia
- Oberklaid-Danks syndrome, see Bohring-Opitz syndrome
- Obesity due to congenital leptin deficiency, see Congenital leptin deficiency
- Obesity due to leptin receptor gene deficiency, see Leptin receptor deficiency
- Obesity, early-onset, adrenal insufficiency, and red hair, see Proopiomelanocortin deficiency
- Obesity, morbid, due to leptin deficiency, see Congenital leptin deficiency
- Obesity, morbid, due to leptin receptor deficiency, see Leptin receptor deficiency
- Obesity, morbid, nonsyndromic 1, see Congenital leptin deficiency
- Obesity, morbid, nonsyndromic 2, see Leptin receptor deficiency
- Obesity, severe, due to leptin deficiency, see Congenital leptin deficiency
- Obesity-hypotonia syndrome, see Cohen syndrome
- Obsessive-compulsive disorder
- Obsessive-compulsive neurosis, see Obsessive-compulsive disorder
- Obstetric cholestasis, see Intrahepatic cholestasis of pregnancy
- Obstructive apnea, see Obstructive sleep apnea
- Obstructive disease of the pulmonary veins, see Pulmonary veno-occlusive disease
- Obstructive sleep apnea
- Obstructive sleep apnea syndrome, see Obstructive sleep apnea
- OCA, see Oculocutaneous albinism
- Occlusive infantile arteriopathy, see Generalized arterial calcification of infancy
- Occupational cramp, see Task-specific focal dystonia
- Occupational dystonia, see Task-specific focal dystonia
- OCD, see Obsessive-compulsive disorder
- OCD, see Familial osteochondritis dissecans
- Ochoa syndrome
- Ocular albinism
- Ocular coloboma, see Coloboma
- Ocular retraction syndrome, see Isolated Duane retraction syndrome
- Ocular rosacea, see Rosacea
- Oculo-dento-digital dysplasia, see Oculodentodigital dysplasia
- Oculo-dento-osseous dysplasia, see Oculodentodigital dysplasia
- Oculo-digito-esophagoduodental (ODED) syndrome, see Feingold syndrome
- Oculo-facio-cardio-dental syndrome, see Oculofaciocardiodental syndrome
- Oculo-oto-facial dysplasia, see Burn-McKeown syndrome
- Oculo-skeletal-abdominal syndrome, see 3MC syndrome
- Oculoauriculovertebral spectrum, see Craniofacial microsomia
- Oculocerebrofacial syndrome, Kaufman type, see Kaufman oculocerebrofacial syndrome
- Oculocerebrorenal syndrome, see Lowe syndrome
- Oculocerebrorenal syndrome of Lowe, see Lowe syndrome
- Oculocutaneous albinism
- Oculocutaneous albinism with leukocyte defect, see Chediak-Higashi syndrome
- Oculodentodigital dysplasia
- Oculodentodigital syndrome, see Oculodentodigital dysplasia
- Oculodentoosseous dysplasia, see Oculodentodigital dysplasia
- Oculofaciocardiodental syndrome
- Oculogastrointestinal muscular dystrophy, see Mitochondrial neurogastrointestinal encephalopathy disease
- Oculootofacial dysplasia, see Burn-McKeown syndrome
- Oculopalatoskeletal syndrome, see 3MC syndrome
- Oculopharyngeal dystrophy, see Oculopharyngeal muscular dystrophy
- Oculopharyngeal muscular dystrophy
- Oculosympathetic palsy, see Horner syndrome
- OD, see Familial osteochondritis dissecans
- ODD syndrome, see Oculodentodigital dysplasia
- ODDD, see Oculodentodigital dysplasia
- ODOD, see Oculodentodigital dysplasia
- Odontoleukodystrophy, see Pol III-related leukodystrophy
- Oestrogen synthetase deficiency, see Aromatase deficiency
- OFCD syndrome, see Oculofaciocardiodental syndrome
- OFDS, see Oral-facial-digital syndrome
- OGD, see Osteoglophonic dysplasia
- OGIMD, see Mitochondrial neurogastrointestinal encephalopathy disease
- Ohaha syndrome, see Infantile-onset spinocerebellar ataxia
- Ohdo syndrome, Maat-Kievit-Brunner type
- Ohdo syndrome, MKB type, see Ohdo syndrome, Maat-Kievit-Brunner type
- Ohdo syndrome, Say-Barber-Biesecker variant, see Ohdo syndrome, Say-Barber-Biesecker-Young-Simpson variant
- Ohdo syndrome, Say-Barber-Biesecker-Young-Simpson variant
- Ohdo syndrome, SBBYS variant, see Ohdo syndrome, Say-Barber-Biesecker-Young-Simpson variant
- OI, see Osteogenesis imperfecta
- Okamoto syndrome, see Au-Kline syndrome
- Okihiro syndrome, see Duane-radial ray syndrome
- OKS, see FG syndrome
- OKT deficiency, see Gyrate atrophy of the choroid and retina
- Old Silk Route disease, see Behçet disease
- Old-aged sensorineural hearing impairment, see Age-related hearing loss
- Oligophrenia microphthalmus, see Norrie disease
- Olivopontocerebellar atrophy I, see Spinocerebellar ataxia type 1
- Ollier disease
- Ollier's syndrome, see Ollier disease
- Omenn syndrome
- Omenn's syndrome, see Omenn syndrome
- Omphalocele, see Abdominal wall defect
- ONCR, see Renal coloboma syndrome
- Ondine syndrome, see Congenital central hypoventilation syndrome
- Ondine-Hirschsprung disease, see Congenital central hypoventilation syndrome
- Onychauxis, hyponychia, and onycholysis, see Nonsyndromic congenital nail disorder 10
- OOFD, see Burn-McKeown syndrome
- OPA3, see Autosomal dominant optic atrophy and cataract
- OPA3 defect, see Costeff syndrome
- OPA3, autosomal dominant, see Autosomal dominant optic atrophy and cataract
- OPCA, see Multiple system atrophy
- OPCH, see Pontocerebellar hypoplasia
- OPD syndrome, type 1, see Otopalatodigital syndrome type 1
- OPD syndrome, type 2, see Otopalatodigital syndrome type 2
- Open spine, see Spina bifida
- Ophthalmo-acromelic syndrome
- Ophthalmoacromelic syndrome, see Ophthalmo-acromelic syndrome
- Ophthalmoplegia, hypotonia, ataxia, hypacusis, and athetosis, see Infantile-onset spinocerebellar ataxia
- Ophthalmoplegia, progressive external, and scoliosis, see Horizontal gaze palsy with progressive scoliosis
- Opiate addiction, see Opioid addiction
- Opiate dependence, see Opioid addiction
- Opioid addiction
- Opioid dependence, see Opioid addiction
- Opitz BBB syndrome, see Opitz G/BBB syndrome
- Opitz BBB/G syndrome, see Opitz G/BBB syndrome
- Opitz G syndrome, see Opitz G/BBB syndrome
- Opitz G/BBB syndrome
- Opitz syndrome, see Opitz G/BBB syndrome
- Opitz trigonocephaly-like syndrome, see Bohring-Opitz syndrome
- Opitz-Frias syndrome, see Opitz G/BBB syndrome
- Opitz-Kaveggia syndrome, see FG syndrome
- OPMD, see Oculopharyngeal muscular dystrophy
- Oppenheim dystonia, see Early-onset isolated dystonia
- Oppenheim's dystonia, see Early-onset isolated dystonia
- OPPG, see Osteoporosis-pseudoglioma syndrome
- Optic atrophy and cataract, autosomal dominant, see Autosomal dominant optic atrophy and cataract
- Optic atrophy plus syndrome, see Costeff syndrome
- Optic atrophy type 1
- Optic atrophy type 3, see Autosomal dominant optic atrophy and cataract
- Optic atrophy, autosomal dominant, see Optic atrophy type 1
- Optic atrophy, cataract, and neurologic disorder, see Autosomal dominant optic atrophy and cataract
- Optic atrophy, hereditary, autosomal dominant, see Optic atrophy type 1
- Optic atrophy, juvenile, see Optic atrophy type 1
- Optic atrophy, Kjer type, see Optic atrophy type 1
- Optic coloboma, vesicoureteral reflux, and renal anomalies, see Renal coloboma syndrome
- Optic nerve coloboma renal syndrome, see Renal coloboma syndrome
- Optic-spinal MS, see Neuromyelitis optica
- Opticoacoustic nerve atrophy with dementia, see Deafness-dystonia-optic neuronopathy syndrome
- Opticospinal MS, see Neuromyelitis optica
- Oral-facial-digital syndrome
- Oral-mandibular-auricular syndrome, see Craniofacial microsomia
- ORAS, see Otulipenia
- Ormond disease, see Retroperitoneal fibrosis
- Ormond's disease, see Retroperitoneal fibrosis
- Ornithine aminotransferase deficiency, see Gyrate atrophy of the choroid and retina
- Ornithine Carbamoyltransferase Deficiency Disease, see Ornithine transcarbamylase deficiency
- Ornithine keto acid aminotransferase deficiency, see Gyrate atrophy of the choroid and retina
- Ornithine transcarbamylase deficiency
- Ornithine translocase deficiency
- Ornithine-delta-aminotransferase deficiency, see Gyrate atrophy of the choroid and retina
- Ornithinemia with gyrate atrophy, see Gyrate atrophy of the choroid and retina
- Oro-facio-digital syndrome, see Oral-facial-digital syndrome
- Orodigitofacial dysostosis, see Oral-facial-digital syndrome
- Orodigitofacial syndrome, see Oral-facial-digital syndrome
- Orofaciodigital syndrome, see Oral-facial-digital syndrome
- Orthostatic hypotension
- OSA, see Obstructive sleep apnea
- OSA syndrome, see 3MC syndrome
- OSAHS, see Obstructive sleep apnea
- OSAS, see Obstructive sleep apnea
- Osler-Vaquez disease, see Polycythemia vera
- Osler-Weber-Rendu syndrome, see Hereditary hemorrhagic telangiectasia
- OSMED, see Otospondylomegaepiphyseal dysplasia
- Osseous Paget's disease, see Paget disease of bone
- Osseous-oculo-dental dysplasia, see Oculodentodigital dysplasia
- Osteitis deformans, see Paget disease of bone
- Osteitis fibrosa disseminata, see McCune-Albright syndrome
- Osteoarthritis
- Osteoarthritis deformans, see Osteoarthritis
- Osteoarthrosis, see Osteoarthritis
- Osteochalasia desmalis familiaris, see Juvenile Paget disease
- Osteochondritis dissecans, short stature, and early-onset osteoarthritis, see Familial osteochondritis dissecans
- Osteodermia, see Progressive osseous heteroplasia
- Osteodysplastic primordial dwarfism type II, see Microcephalic osteodysplastic primordial dwarfism type II
- Osteodysplasty of Melnick and Needles, see Melnick-Needles syndrome
- Osteoectasia with hyperphosphatasia, see Juvenile Paget disease
- Osteogenesis imperfecta
- Osteogenesis imperfecta with unusual skeletal lesions, see Gnathodiaphyseal dysplasia
- Osteogenesis imperfecta, Levin type, see Gnathodiaphyseal dysplasia
- Osteogenesis imperfecta, ocular form, see Osteoporosis-pseudoglioma syndrome
- Osteoglophonic dwarfism, see Osteoglophonic dysplasia
- Osteoglophonic dysplasia
- Osteoma cutis, see Progressive osseous heteroplasia
- Osteopathia condensans disseminata, see Buschke-Ollendorff syndrome
- Osteopetroses, see Osteopetrosis
- Osteopetrosis
- Osteoporosis-pseudoglioma syndrome
- Osteosis cutis, see Progressive osseous heteroplasia
- Osterreicher syndrome, see Nail-patella syndrome
- Oto-palato-digital syndrome, type I, see Otopalatodigital syndrome type 1
- Oto-palato-digital syndrome, type II, see Otopalatodigital syndrome type 2
- Oto-spondylo-megaepiphyseal dysplasia, see Otospondylomegaepiphyseal dysplasia
- Otogenic vertigo, see Ménière disease
- Otomandibular dysostosis, see Craniofacial microsomia
- Otopalatodigital syndrome type 1
- Otopalatodigital syndrome type 2
- Otospondylomegaepiphyseal dysplasia
- Otospondylomegaepiphyseal dysplasia, autosomal dominant, see Weissenbacher-Zweymüller syndrome
- OTULIN-related autoinflammatory syndrome, see Otulipenia
- Otulipenia
- Ovarian cancer
- Ovarian carcinoma, see Ovarian cancer
- Ovarian dysgenesis with sensorineural deafness, see Perrault syndrome
- Owren disease, see Factor V deficiency
- Owren's disease, see Factor V deficiency
- Oxalosis, see Primary hyperoxaluria
- Oxaluria, primary, see Primary hyperoxaluria