The spectrum of cavitary optic disc anomalies in a family.

The current classification of cavitary optic disc anomalies including the morphologically related entities--optic nerve pit, morning glory disc anomaly, coloboma of the optic nerve, and retinochoroidal coloboma involving the optic nerve--is inexact and confusing. Traditionally, these disc abnormalities have been regarded as distinct morphologic anomalies. Thirty-five members of a five-generation kindred with autosomal dominantly inherited optic disc anomalies were examined. Observed abnormalities in this pedigree comprised a spectrum of morphologic variants ranging from large anomalous discs to typical pits and colobomas. The findings in this family suggest a variable expression of a single autosomal dominant defect rather than the chance occurrence of three separate, distinct, but morphologically similar entities occurring in a single pedigree.