Frequency of different subtypes of spinocerebellar ataxia in the Han nationality of Hunan province in China

Objective To determine the frequency of different subtypes of spinocerebellar ataxias (SCAs) in the Han nationality of Hunan province in China. Methods The mutations of SCA1, SCA2, SCA3,SCA6, SCA7, SCA17, and dentatorulral-pallidoluysian (DRPLA) were detected with the polymerase chain reaction (PCR), denaturing polyacrylamide gel and DNA sequencing techniques in 139 autosomal dominant SCA families and 61 sporadic SCA patients. Results Of the 139 families,11 (7.9%) were positive for SCA1, 9(6.5%) were positive for SCA2, 71(51.1%) were positive for SCA3, 4(2.9%) were positive for SCA6, 2(1.4%) were positive for SCA7,and none was positive for SCA17 and DRPLA. There was 1 SCA2 patient, 3 SCA3 patients,1 SCA6 patient in the 61 sporadic SCA patients. Conclusion The frequency of SCA3 is substantially higher than that of SCA1 and SCA2 in the autosomal dominant SCA patients in the Han nationality of Hunan province. SCA6 and SCA7 are rare subtypes.