X-linked mental retardation and/or hydrocephalus

A family in which a brother and 5 sons of five sisters were mentally retarded without major physical abnormality, is reported. Two hydrocephalic males also occurred in the family. The possibility is entertained that in this family (and probably in others) an X-linked gene caused either non-specific mental retardation or hydrocephalus associated with mental retardation. Some minor physical and neurological abnormalities were found in some of the affected males, and their intelligence varied considerably within the retarded range.