A 6-year-old boy, whose parents were first cousins, had congenital retinal nonattachment in one eye and a falciform fold in the other. He had had a shunt operation for hydrocephaly. Oxygen was never administered and test results for rubella and toxoplasmosis were negative. The consanguinity in this case indicates the syndrome is an autosomal recessive trait. This and other hereditary disorders with congenital retinal nonattachment have previously been misinterpreted as retrolental fibroplasia occurring without oxygen treatment.