二代测序技术在杜氏肌营养不良症家系中的分子诊断应用

Application of next-generation sequencing in the molecular diagnosis of Duchenne muscular dystrophy

摘要:

对22例临床拟诊断为杜氏肌营养不良症（DMD）患儿的家系临床资料进行分析，探讨二代测序（NGS）技术在DMD患者分子诊断中的临床应用价值。先证者同时送检遗传性神经肌肉病相关panel行NGS检测和Dystrophin基因多重连接探针扩增术（MLPA）检测，分析两种方法检出的Dystrophin基因外显子缺失/重复突变结果，Dystrophin基因点突变经Sanger测序验证。通过NGS测序，22例先证者均检出Dystrophin基因突变，其中外显子缺失/重复型突变14例，点突变及微小变异8例。MLPA检测结果与NGS检测结果一致。Sanger测序结果显示NGS检测出的点突变及微小变异是正确的。1例错义突变c.6290G>T，1例无义突变c.3487C>T，4例微小缺失导致的移码突变c.1208delG、c.7497_7506delGGTGGGTGAC、c.9421_9422delAA、c.8910_8913delTCTC在人类基因突变数据库中均未见报道，为Dystrophin基因新突变。该研究结果显示NGS技术可全面检测Dystrophin基因外显子缺失/重复、点突变、微小缺失和内含子突变等变异，在DMD患者分子诊断中的临床应用有一定价值，值得推广。

Abstract:

The purpose of this study is to analyze the family's clinical data of 22 children who were given an intended clinical diagnosis of Duchenne muscular dystrophy (DMD), and to explore the clinical value of next-generation sequencing (NGS) in the molecular diagnosis of DMD. The probands were simultaneously tested by NGS for a gene panel associated with hereditary neuromuscular disease and multiplex ligation-dependent probe amplifcation (MLPA) for the Dystrophin gene. The exon deletion/repetition mutations of the Dystrophin gene determined by both methods were compared and the point mutations of the Dystrophin gene were verifed by Sanger sequencing. Dystrophin gene mutations were found in all the 22 probands, including 14 exon deletion/repetition mutations and 8 point mutations/minor variations. The results of MLPA detection were consistent with those of NGS. The results of Sanger sequencing showed that the point mutations and minor variations determined by NGS were correct. One missense mutation (c.6290G>T), 1 nonsense mutation (c.3487C>T) and 4 minor deletion-induced frameshift mutations (c.1208delG, c.7497_7506delGGTGGGTGAC, c.9421_9422delAA and c.8910_8913delTCTC) had not been reported in the Human Gene Mutation Database, and thus were considered as novel mutations of the Dystrophin gene. The results of this study showed that NGS can detect variations in the Dystrophin gene, including exon deletion/repetition, point mutation, minor deletion and intron mutation. Therefore, NGS is of certain clinical value in the molecular diagnosis of DMD and is worthy of recommendation.