EXTRAPYRAMIDAL SIGNS ARE A COMMON FEATURE OF SPINOCEREBELLAR ATAXIA TYPE 17

Abstract

Spinocerebellar ataxia type 17 (SCA17) is a CAG repeat expansion disorder in the TATA-binding protein (TBP) gene.1 Previous studies have shown that SCA17 is a rare cause of ataxia, especially in the East.2,3 SCA17 may show nonataxic manifestations, such as choreic movement, cognitive decline, dystonia, parkinsonism, and pyramidal tract signs. Previously we reported that SCA17 is not rare among our parkinsonian patients (0.9%).4 Thus, we examined the frequency of SCA17 among Korean patients with ataxia or chorea as a main phenotype. ### Methods. Gene samples obtained from the Movement Disorder Gene Bank of Seoul National University Hospital collected until April 2007 were analyzed. All patients were native Koreans. Written informed consent was obtained from all subjects before blood sampling for gene studies, and the genetic study was approved by our Institutional Review Board. Patients with a positive gene test for SCA1, 2, 3, 6, 7, dentatorubropallidoluysian atrophy, or Huntington disease (HD) were excluded. In both groups, acquired causes were excluded. We did not exclude the patients with familial history of ataxia or chorea. Finally, 661 ataxia patients and 98 chorea patients were included (2 patients had both ataxia and chorea). The method of gene analysis used is described in the previous report.4 ### Results. The 2 patients with both ataxia and chorea were found to have …