Obstructive asymmetric septal hypertrophy
A rare heart disorder where thickening of parts of the heart (wall separating the heart chambers) reduces the size of heart chambers and hinders the flow of blood.
Diseases
Occipital horn syndrome
Occipital horn syndrome was formerly considered a variant of Ehlers-Danlos syndrome. An X-linked recessive disorder, this variant is characterized by a deficiency in biliary copper excretion that causes deformations in the skeleton. These include projections on the back of the skull (parasagittal bone exostoses arising from the occipital bone—the so-called "occipital horns") as well as deformities of the elbow, radial head dislocation, hammer-shaped lateral ends of the clavicles, and abnormalities of the hips and pelvis.
Occult spinal dysraphism
A rare disorder characterized by progressive neurological deterioration due to compression of the spinal cord in the spine.
Ochronosis
Ochronosis, often called alkaptonuric ochronosis, is an autosomal recessive metabolic disorder that causes an excess of homogentisic acid, resulting in adverse pigmentation, calcification, and inflammation of cartilagenous and related tissue throughout the body. The disorder is a result of incomplete metabolism of homogentisic acid, tyrosine and phenylalanine
Ochronosis- hereditary
Alkaptonuria (black urine disease or alcaptonuria) is a rare inherited genetic disorder of phenylalanine and tyrosine metabolism. This is an autosomal recessive condition that is due to a defect in the enzyme homogentisate 1,2-dioxygenase (EC 1.13.11.5), which participates in the degradation of tyrosine. As a result, a toxic tyrosine byproduct called homogentisic acid (or alkapton) accumulates in the blood, and is excreted in urine in large amounts(hence -uria). Excessive homogentisic acid causes damage to cartilage (ochronosis, leading to osteoarthritis) and heart valves as well as precipitating as kidney stones. Treatment with nitisinone, which suppresses homogentisic acid production, is being studied.[1] Alkaptonuria is more common in Slovakia and the Dominican Republic than in other countries.[2][3]
Ocular Albinism type 1
A rare eye disorder characterized primarily by lack of eye pigmentation. Females tend to have few if any symptoms as the condition is X-linked.
Ocular cicatricial pemphigoid
A rare chronic autoimmune eye condition that can result in blindness if not treated. The conjunctival and mucosal layers of the eye (inside of eyelid and outside of eye) become progressively inflamed and scarred. The condition can be very difficult to treat.
Ocular coloboma-imperforate anus
Coloboma of the iris (giving the appearance of a vertical pupil, hence the name "cat eye"), atresia of the anus, preauricular tags or fistulae, congenital cardiovascular abnormalities, urinary tract anomalies, and reduced growth rate. Mental retardation is not a consistent feature and, when present, it is usually mild.
Ocular colobomas- ichthyosis- brain malformations and endocrine abnormalities
Ocular convergence spasm
A rare condition where the eyes intermittently converge or turn towards each other.
Ocular melanoma
A type of cancer that develops in the eye. The cancer develops from pigment-producing cells called melanocytes. This cancer becomes more common with increasing age.
Ocular motility disorders
Any eye disorder that involves problems with moving the eyes which can cause vision problems and or abnormal alignment of the eyes. Examples of ocular motility disorders includes Duane retraction syndrome, Adie's syndrome, strabismus, nystagmus and ophthalmoplegia.
Ocular Muscular Dystrophy
A slow progressing paralysis of the muscles surrounding the eyes. Eventually the eyes are unable to move.
Ocular toxoplasmosis
Ocular toxoplasmosis is the commonest identifiable cause of posterior uveitis. It predominantly affects children and young people (25-45 years) and is characterised by recurrences that can ultimately lead to significant visual loss. Toxoplasma gondii is an obligate intracellular parasite with the cat as the definitive host. It is transmitted to humans by accidental ingestion of the egg form (oocysts) in cat faecal matter which may contaminate fruit and vegetables, ingestion of the cyst form (bradyzoites) in undercooked or raw meat, and vertical transmission to the fetus during maternal primary infection by the replicating form (tachyzoites). Most clinical episodes of ocular toxoplasmosis represent reactivation of an infection that was acquired in utero. It is likely however, that more patients with ocular disease acquire toxoplasmosis after birth than was previously recognised.
Oculo cerebral dysplasia
A very rare syndrome characterized by small eyes, optic nerve abnormality and a brain anomaly (Dandy-Walker cyst)
Oculo cerebro acral syndrome
A very rare syndrome characterized mainly by eye, brain, ear and limb abnormalities
Oculo cerebro osseous syndrome
A very rare syndrome characterized mainly by eye, brain and bone abnormalities.
Oculo digital syndrome
Oculodentodigital syndrome (ODD syndrome) is an extremely rare genetic condition that typically results in small eyes, underdeveloped teeth, and syndactyly and malformation of the fourth and fifth fingers. It has also been called oculo-dento-digital syndrome, oculodentodigital dysplasia (ODDD), and oculodentoosseous dysplasia (ODOD). It is considered a kind of ectodermal dysplasia.
Oculo skeletal renal syndrome
A very rare syndrome characterized mainly by eye, skeletal and kidney problems
Oculo tricho anal syndrome
A very rare syndrome characterized mainly by eye, brain and bone abnormalities.
Oculo tricho dysplasia
A very rare syndrome characterized mainly by eye, tooth and hair abnormalities.
Oculo-dento-digital syndrome
Oculodentodigital syndrome (ODD syndrome) is an extremely rare genetic condition that typically results in small eyes, underdeveloped teeth, and syndactyly and malformation of the fourth and fifth fingers. It has also been called oculo-dento-digital syndrome, oculodentodigital dysplasia (ODDD), and oculodentoosseous dysplasia (ODOD). It is considered a kind of ectodermal dysplasia.
Oculo-gastrointestinal muscular dystrophy
A very rare form of muscle wasting disease involving the eye and gastrointestinal muscles
Oculoauriculofrontonasal syndrome
A rare syndrome characterized mainly by eye, ear, facial and nasal abnormalities.
Oculocerebral hypopigmentation syndrome Cross type
A rare inherited disorder involving lack of pigmentation and eye and brain defects caused by central nervous system abnormalities.
Oculocerebral hypopigmentation syndrome type Preus
A very rare syndrome characterized mainly by eye, brain and pigmentation abnormalities
Oculocerebral syndrome with hypopigmentation
A rare inherited disorder involving lack of pigmentation and eye and brain defects caused by central nervous system abnormalities.
Oculocerebrocutaneous syndrome
A rare birth disorder characterized by eye cavity cysts, brain anomalies, facial skin tags and various other skin lesions.
Oculocerebrorenal syndrome
Oculocerebrorenal syndrome (also called Lowe syndrome) is a X-linked recessive disorder characterized by hydrophthalmia, cataracts, intellectual disabilities, aminoaciduria, reduced renal ammonia production and vitamin D-resistant rickets.
Oculocutaneous albinism type 1
A rare inherited disorder characterized by complete lack of pigmentation in the skin, eyes and hair. Type 1A involves a complete absence of tyrosinase which is needed for the production of melanin which gives the skin, hair and eyes their color - type B involves only a partial absence of tyrosinase. It is caused by mutations in the TYR gene