Clinical features and ATTCT repeat expansion in spinocerebellar ataxia type 10.

Background: Spinocerebellar ataxia type 10, an autosomal dominant disease characterized by ataxia and seizures, is caused by a large expansion of an unstable ATTCT pentanucleotide repeat.

Objectives: To characterize the phenotypic expression of spinocerebellar ataxia type 10 and to examine the genotype-phenotype correlations in 2 large families.

Design: Clinical characterization and genotype-phenotype correlation.