SCA17 repeat expansion: Mildly expanded CAG/CAA repeat alleles in neurological disorders and the functional implications

Chiung Mei Chen, Li Ching Lee, Bing Wen Soong, Hon Chung Fung, Wen Chuin Hsu, Pei Ying Lin, Hui Ju Huang, Fen Lin Chen, Cheng Yueh Lin, Guey Jen Lee-Chen*, Yih Ru Wu

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)


Background: Spinocerebellar ataxia type 17 (SCA17) involves the expression of a CAG/CAA expansion mutation in the gene encoding TATA-box binding protein (TBP), a general transcription initiation factor. The spectrum of SCA17 clinical presentation is broad. Methods: We screened for triplet expansion in the TBP gene in Taiwanese Parkinson's disease (PD), Alzheimer's disease (AD) and atypical parkinsonism and investigated the functional implication of expanded alleles using lymphoblastoid cells as a model. Results: A total of 6 mildly expanded alleles (44-46) were identified in patients group. The frequency of the individuals carrying expanded alleles in PD (3/602 [0.5%]), AD (2/245 [0.8%]) and atypical parkinsonism (1/44 [2.3%]) is not significant as compared to that in the control subjects (0/644 [0.0%]). In lymphoblastoid cells, HSPA5, HSPA8 and HSPB1 expression levels in cells with expanded TBP were significantly lower than that of the control cells. Although not significantly, the levels of PARK7 protein isoforms 6.1 and 6.4 are notably increased in SCA17 lymphoblastoid cells. Treatment of TBH (tert-butyl hydroperoxide) significantly increases cell death in the cells with mildly expanded TBP. Conclusions: Our findings expand the spectrum of SCA17 phenotype and may contribute to our understanding of the disease.

Original languageEnglish
Pages (from-to)375-380
Number of pages6
JournalClinica Chimica Acta
Issue number5-6
Publication statusPublished - 2010 Mar 2


  • Clinical study
  • Expression analysis
  • Lymphoblastoid cells
  • SCA17
  • TBP expansion

ASJC Scopus subject areas

  • Biochemistry
  • Clinical Biochemistry
  • Biochemistry, medical


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