The spinocerebellar ataxias (SCAs) are a clinically and genetically heterogeneous group of neurodegenerative disorders. To date, ten SCA loci have been described (SCA1-SCA8, SCA10 and SCA11), with six genes having been cloned (SCA1, SCA2, SCA3/MJD, SCA6, SCA7 and SCA8) and shown to contain CAG/CTG repeats. / This study investigated various aspects of the SCA2, SCA6, and SCA7 subtypes. Haplotype analysis in our panel of SCA2 families identified multiple ancestral mutation events to be responsible for disease in this group. Screening for the newly identified SCA6 and SCA7 mutations in our large collection of SCA families and patients revealed that these mutations are rare in our panel, each accounting for less than 1% of our ataxia samples. Finally, the CAG repeat-containing locus hGT1 was found to be associated with residual age at onset variability in our SCA2 families. / Together, these results add to our growing understanding of the SCAs, and bring us a few steps closer to effective diagnoses of, and treatments for, these devastating diseases.

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