We have assessed the haplotypes at the ATXN2 locus in Taiwanese controls and in individuals with SCA2 ataxia with both ataxic and parkinsonian features. Our intention was to determine whether a different ataxin 2 haplotypes predisposed to the two phenotypes. In fact, our analysis showed that all SCA2 mutations carriers had the same ataxin 2 haplotype: haplotype B, which accounts for only 15% of control haplotypes, implying that there is a common founder for all Taiwanese SCA2 patients.