Late-onset variant of Huntington's chorea.

We identified a large Georgia kinship in which a hereditary autosomal dominant chorea appeared at an average age of 65 years, much later than usual for Huntington's chorea. Progression was slow. Dementia was not an obvious initial feature. Family members denied that affected persons became demented, and those affected cognitively intact with bedside testing. However, deficits of memory were apparent on formal psychologic testing. In the propositus' generation, five of 12 siblings were affected during their 60s. Of 23 persons in a younger generation, aged 30 to 60 years, none was yet affected. A number of variants of Huntington's chorea have been proposed. In elderly patients without obvious dementia, psychologic testing may be of diagnostic importance, revealing characteristic memory deficits. When the disorder consistently occurs at an advanced age and progresses slowly, the implications for the family may be less grave than with Huntington's chorea of earlier onset.