脊髓小脑共济失调3型临床变异型特征及突变分析

The characteristics of clinical variation and mutation analysis on spinocerebellar ataxia type 3

目的探讨脊髓小脑共济失调3型临床变异型特征。方法应用CEQ8000核酸分析仪对1个表型为变形性肌张力障碍家系和2个表型为痉挛性截瘫家系的SCA3/MJD基因胞嘧啶-腺嘌呤-鸟嘌呤(CAG)重复序列进行基因片段分析。结果基因学检查证实3个家系均为SCA3/MJD基因CAG重复扩增突变致病。结论我国脊髓小脑共济失调3型存在变形性肌张力障碍和痉挛性截瘫的临床变异型。脊髓小脑共济失调3型的多种临床变异类型为调节因素假说提供了进一步的证据,并且提示在临床工作中应注意避免遗漏阳性家系。

Objective To investigate the characteristics of clinical variation of spinocerebellar ataxia type 3 （SCA3）. Methods Gene fragment analysis based on CEQ8000 sequencer were applied to analyse the cytosine-adenine-guanine （CAG） repeat of SCA3/MJD gene in 1 torsion dystonia pedigree and 2 spastic paraplegia pedigrees. Results These pedigrees were genetically determined SCA3 by the expended CAG repeat of SCA3/MJD gene. Conclusion SCA3 might include the clinical subtypes as torsion dystonia and spastic paraplegia in China. These findings indicate that the clinical variation of SCA3 might cover a wider spectrum than previously reviewed. The high clinical pleomorphism strongly supports that SCA3 phenotype is modulated by modifier factors. It is suggested to avoid missed diagnosis in positive family.