X-linked hydrocephalus.

Two French-Canadian families with seven cases of hydrocephalus in two generations are presented. The pattern of inheritance is consistent with an X-linked recessive transmission. The clinical and pathologic characteristics of this entity are reviewed. The anomaly of adducted thumbs was present in one patient and its cause is considered. The hypothesis of primary hydrocephalus and secondary compression of the aqueduct as the mechanism for aqueductal stenosis is discussed.