Oculocutaneous albinism
Oculocutaneous albinism (OCA) is an inherited condition characterized by hypopigmentation of the skin, hair, and eyes. Ocular involvement is often severe with photophobia, decreased visual acuity due to foveal hypoplasia, nystagmus, and strabism secondary to defective routing of optic axons in the chiasma. Cutaneous hypopigmentation is responsible for diminished photoprotection that places patients at increased risk for skin cancers. OCA also occurs in a number of life-threatening conditions, including Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, and Griscelli-Prunieras syndrome. Most cases of OCA are inherited on an autosomal recessive basis. Several mutations have recently been identified in type I OCA or "tyrosinase-negative" OCA. Identification of other genetic abnormalities will probably occur in the future and will lead to more accurate classification of OCA syndromes.