X-linked recessive inheritance of ataxia and adult-onset dementia: clinical features and preliminary linkage analysis.

Three generations of a family exhibit a unique syndrome of X-linked ataxia, pyramidal tract signs, and adult-onset dementia. Initial signs, manifested by 2 to 3 years of age, are delayed walking and tremor. During their teens, the patients develop mild but progressive ataxia and pyramidal tract signs. Memory problems in the third decade initiate a progressive dementia, leading to death in the sixth decade. Laboratory investigations failed to disclose a biochemical basis for the syndrome. Preliminary molecular linkage studies have been conducted, and although the specific position of the responsible gene on the X chromosome has not yet been determined, the q26-qter region and much of the p arm are unlikely sites for this gene. The linkage studies are continuing.