Molecular and clinical study of spinocerebellar ataxia type 17

Objective To investigate the clinical features and genetic mutations of spinocerebellar ataxia type 17 (SCA17). Methods The pathological CAG triplet repeat expansions of the SCA3，SCA1，SCA2，SCA6，SCA7，SCA8，SCA12，SCA17 and dentatorubral pallidoluysian atrophy genes were analyzed in 708 probands of autosomal dominant familial SCA and 119 sporadic SCA cases. The CAG repeats of TATA-binding protein (TBP) gene were amplified by means of polymerase chain reaction and agarose gel electrophoresis. For the samples with two alleles, fragment analysis based on CEQ8000 sequencer was applied to analyze the CAG repeat numbers. Furthermore, the correlation between clinical features and CAG repeat in the TBP gene was studied carefully. Results The expanded CAG repeats in the TBP gene was detected in 5 cases with 37/50, 36/45, 38/52, 38/53, 36/54 separately. And the main clinical manifestations were ataxia and memory impairment. Conclusion These findings indicate that SCA17 might be a rare subtype of SCA in the Chinese population and the clinical features of SCA17 cover a wider spectrum than previously reviewed. Key words: Spinocerebellar ataxias; TATA-box binding protein; Trinucleotide repeats; Mutation