脊髓小脑型共济失调Ⅱ型(CAG)n突变检测研究

目的 探讨我国遗传性脊髓小脑型共济失调Ⅱ型（ＳＣＡ２）基因突变特点及临床表型。方法 采用聚合酶链式反应、变性聚丙烯酰胺凝胶电泳和银染技术，检测分析８５个中国ＳＣＡ家系１６７例患者的ＳＣＡ（ＣＡＧ）ｎ。结果 ５个家系１２例患者与１名无症状者存在ＳＣＡ２（ＣＡＧ）ｎ扩展突变，拷贝数为４０～４７；其余８０个家系１５５例患者的（ＣＡＧ）ｎ考贝数为１３～３０，ＳＣＡ２患者临床以肌张力下降腱反射减弱和智能障碍

Characteristicsof spinocerebellar ataxia type 2 gene mutation dictation in hereditary spinocerebellarataxia

Objective To assess the clinical phenotype and characteristics of spinocerebellar ataxia type 2(SCA2)gene mutation in Chinese patients with spinocerebellar ataxia (SCA) Methods The polymorphic(CAG)n copies in SCA2 gene were determined with polymerase chain reaction and denaturing polyacrylamide gel electrophoresis analysis in 167 SCA patients from 85 unrelated Chinese autosomal dominant SCA kindreds Results The mutated SCA2 alleles ranging from 42 to 47 CAG repeats were observed in 12 patients from 5 kindreds, while the normal alleles ranging from 13 to 30 repeats One asymptomatic individual had an expanded allele of 40 CAG repeats The SCA2 patients had mainly cerebella ataxia, dysarthria, hypotonia, decreased reflex, visual loss, swallow difficulty and dementia In addition, the size of expanded (CAG )n copies was inversely correlated with the age of onset of SCA2 Conclusion Although (CAG)n copiers have influence on disease phenotype, they can not be considered as the only predictable index of clinical features