Yellow nail syndrome associated with mental retardation in two siblings.

Two siblings with yellow nail syndrome and mental retardation are described. In addition to nail changes, the younger brother was found to have congenital lymphoedema and idiopathic pleural effusion, and the elder brother, lymphoedema praecox. They had in common a history of respiratory tract infections. Their intelligence quotient as measured by the Suzuki-Binet tests was 30% and 70%, respectively.