Has spinocerebellar ataxia type 2 a distinct phenotype? Genetic and clinical study of an Italian family.

The gene for spinocerebellar ataxia type 2 (SCA2) is mapped to chromosome 12q23-24.1. Using D12S79 and D12S105, we performed linkage analysis in nine individuals including six affected members of a four-generation family in which we excluded SCA1 by direct mutation analysis. We obtained a lod score = 2.37 at theta = 0.00 for the compound haplotype. The clinical picture appeared homogeneous, showing the absence of corticospinal signs and the presence of peripheral neuropathy. The present study suggests that this SCA2 family is clinically different from most SCA1 families.