Mutation at the SCA17 locus is not a common cause of primary dystonia

Spinocerebellar ataxia type 17 (SCA17) is a dominant progressive neurodegenerative disorder, caused by a triplet repeat expansion within the TATA-binding protein. As well as ataxia and dementia, Parkinsonism and dystonia are common in SCA17. In some pedigrees focal dystonia in the absence of ataxia has been described as a main clinical feature. To evaluate the relevance of SCA17 mutations for primary dystonia, we examined the TBP repeat expansion in a series of 288 patients with different subtypes of primary torsion dystonia. We did not find any repeat sizes in the pathogenic range. We conclude that the SCA17 repeat expansion is not a common cause of familial and sporadic dystonia.