oculocutaneous albinism

albinism /al·bi·nism/ (al´bĭ-nizm) congenital absence, either total or partial, of normal pigmentation in the body (hair, skin, eyes) due to a defect in melanin synthesis.albinot´ic

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ocular albinism  that in which skin and hair pigmentation is virtually or wholly normal, with ocular abnormalities varying by type.

oculocutaneous albinism  (OCA) a human albinism occurring in ten types, all having in common decreased melanotic pigmentation of the hair, skin, and eyes, hypoplastic foveas, photophobia, nystagmus, and decreased visual acuity.

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oculocutaneous albinism (OCA)

[ok′yo̅o̅lōkyo̅o̅tā′- nē·əs]

a human albinism occurring in ten types, all distinguished in their incidence and genetic, biochemical, and clinical characteristics but having in common varying degrees of decreased melanotic pigment of the skin, hair, and eyes; hypoplastic foveas; photophobia; nystagmus; and decreased visual acuity.

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albinism 

Congenital anomaly due to a defect of melanin production as a result of one of several possible genetic defects. Oculocutaneous albinism type 1(OCA1) is due to a genetic defect in tyrosinase, the enzyme that metabolizes the amino acid tyrosine, which is essential for its conversion to melanin (formerly called tyrosinase-negative albinism). It is an autosomal recessive condition, which affects the skin, hair and eyes. The iris is a pale colour, the fundus and the pupil are reddish and the eye transilluminates markedly. There is poor visual acuity, photophobia, nystagmus and strabismus. Oculocutaneous type 2 (OCA2) is caused by a mutation of the OCA2 ('P') gene resulting in variable amounts of melanin synthesis. The hypopigmentation of the eyes, skin and hair varies from fair to normal (formerly called tyrosinase-positive albinism). It may be associated with the Hermansky-Pudlak syndrome in which there is albinism and easy bruising or bleeding. The other type of albinism is ocular albinism type 1 (OA1). It is inherited either as an X-linked or less commonly as an autosomal recessive trait. It affects mainly the eyes and in most instances males only and the skin colour is usually normal. Management involves full correction, possibly with tinted lenses. Surgery may be required for strabismus. See ocular fundus; inheritance; trans-illumination.