LETTERS TO THE EDITOR Familial hydrocephalus

Familial cases of congenital hydrocephalus have often been reported and may result from distinct monogenic disorders or may be mul-tifactorially determined.1 The commonest cause is X linked hydrocephalus associated with stenosis of the aqueduct of Sylvius and, in most families, the genetic basis of this con-dition is known.2 By contrast, familial adult onset cases are unusual and the genetic basis is unknown.3 We report a family in which the presumed mode of inheritance is autosomal dominant with variable penetrance. The family pedigree is shown in figure 1. There was no consanguinity. Patient II-1 was a 76 year old man wh