Systemic associations of uveal coloboma.

Closure of the optic cleft occurs about the sixth week of intrauterine life. Clinically, failure of complete closure results in a coloboma of the uveal tract which is variable in its position and extent, and there is sometimes also an associated coloboma of the optic nervehead; defective closure of the cleft is known to be under genetic influence. The usual mode of transmission of such a defect is dominant, but a recessive inheritance, a probable sex- linked transmission (Goldberg and McKusick, I97 i), and an apparently sporadic incidence