中国人群中抗肌萎缩蛋白基因突变类型和分布特点及其与临床症状的相关性

Association of mutation types and distribution characteristics of dystrophin gene with clinical symptoms in Chinese population

假性肥大型进行性肌营养不良症(Duchenne’s muscular dystrophy,DMD)是源于横纹肌的一种X-连锁隐性致死性遗传病,由编码抗肌营养不良蛋白(dystrophin)基因突变所致。为了探讨中国人群中DMD患者的dystrophin基因突变类型和分布特点及其与临床症状的相关性,文章采用Multiplex Ligation-Dependent Probe Amplification(MLPA)方法对720例DMD患者及其母亲和20例正常成年男性进行dystrophin基因分析。结果显示,检出率为64.9%(467/720),54.3%(391/720)的患者为基因缺失;10.6%(76/720)的患者为基因重复。累及Exon45-54缺失突变型占全部缺失型患者的71.9%(281/391);重复突变型累及Exon1-40占全部重复型患者82.9%(63/76);检出的患者中,DMD型和中间型营养不良症(Intermediate muscular dystrophy,IMD)型占90.6%(423/467),Becker型营养不良症(Becker muscular dystrophy,BMD)型占9.4%(44/467)。表明假肥大型肌营养不良症以dystrophin基因缺失突变为主,突变发生在整个基因中非均匀分布,存在突变热区,在缺失和重复的位置和片段长度与肌病的临床症状严重程度之间并不存在简单的相关关系。

Duchenne muscular dystrophy（DMD） is X-linked disorder caused by mutations in the dystrophin gene.To investigate mutation types and distribution characteristics of dystrophin gene in Chinese DMD patients,we used Multiplex Ligation-Dependent Probe Amplification（MLPA） to analyze the dystrophin gene in 720 DMD patients,their mothers,and 20 normal adult males.Results showed that detection rate was 64.9%（467/720） in all the patients,gene deletion rate was 54.3%（391/720）,and gene duplication rate was 10.6%（76/720）.The rate of deletion mutant occurred in Exon 45-54 was 71.9%（281/391） in all gene deletion patients;meanwhile,the rate of gene duplication occurred in Exon 1-40 was 82.9%（63/76） in all gene duplication ones.In all the patients with gene deletion and duplication,the rate of DMD and IMD was 90.6%（423/467）,and BMD,9.4%（44/467）.This indicates that the main reason of duchenne muscular dystrophy is dystro-phin gene deletion mutation,which would occur in any gene unevenly with hot spots of mutation.The location and frag-ment length of gene deletion and duplication cannot decide the severity of clinical symptoms directly.