Clinical features of chromosome 16q22.1 linked autosomal dominant cerebellar ataxia in Japanese.

Chromosome 16q22.1-linked autosomal dominant cerebellar ataxia (16q-ADCA) is strongly associated with a substitution in the puratrophin-1 gene. This locus overlaps with spinocerebellar ataxia type 4 (SCA4) which shows ataxia with prominent sensory axonal neuropathy. We found that 16q-ADCA is a common ADCA subtype in the Tohoku District of Japan. The clinical feature of Japanese 16q-ADCA is characterized as late-onset pure cerebellar ataxia.