脊髓小脑性共济失调是一类由于遗传因素造成的单基因神经系统变性性疾病 ,不同位点的三核苷酸重复扩增导致不同的遗传亚型。已经发现 2 2种亚型的脊髓小脑性共济失调 ,多数是由于致病基因内存在 CAG重复片段异常扩增 ,导致含有多聚谷氨酰胺链的突变蛋白在细胞核内沉积形成核内包涵体。本文就其最近的分子遗传学进展作简要综述 Spinocerebellar ataxia is a group of single-gene nervous system degenerative diseases caused by genetic factors. Trinucleotide repeat amplification at different sites leads to different genetic subtypes. Spinocerebellar ataxias of the 22 subtypes have been found to be mostly due to the abnormal amplification of CAG repeats in the causative gene resulting in the deposition of mutein containing polyglutamine chains within the nucleus . This article gives a brief overview of recent advances in molecular genetics