Oculocutaneous albinism: variable expressivity of nystagmus in a sibship.

Traditionally, the diagnosis of ocular or oculocutaneous albinism (OCA) is based on a constellation of features including the presence of nystagmus associated with iris transillumination defects, hypopigmentation of the fundus, and hypoplasia of the fovea and optic nerve head. Nystagmus is the most frequent ocular sign for the ascertainment of albinism particularly in individuals who have lightly-pigmented parents. We report two siblings, a male and female, with minimal, if any, pigmentation of skin and hair, iris transillumination defects, blond fundi, and hypoplasia of the foveae and optic nerve heads who were discordant for nystagmus; the diagnosis of OCA was based on the clinical findings. These siblings presumably have the same genetic hypopigmentation defect and demonstrate that nystagmus is not a consistent finding in OCA and may not be an absolute criterion for diagnosis.