Test Background
Oculocutaneous albinism (OCA) type 1 is caused by mutations in the tyrosinase gene (TYR, or OCA1). Oculocutaneous albinism type 1 (OCA1) is characterized by hypopigmentation of the skin and hair. Eye findings include nystagmus; reduced iris pigment with iris translucency; reduced retinal pigment; foveal hypoplasia with substantial reduction in visual acuity, usually in the range of 20/100 to 20/400; and misrouting of the optic nerve fiber radiations at the chiasm resulting in strabismus, reduced stereoscopic vision, and altered visually evoked potentials (VEP). Individuals with OCA1A have white hair, white skin that does not tan, and fully translucent irides, none of which darken with age. Individuals with OCA1B have white or very light yellow hair that darkens minimally with age, white skin that over time develops some minimal generalized pigment and may tan slightly with judicious sun exposure, and blue irides that darken to green/hazel or light brown/tan with age The clinical sensitivity of this test is approximately 80%. This laboratory performs Sanger sequencing of the TYR gene.
