全外显子组测序发现一家族性扩张型心肌病致病基因

Identification of gene mutation associated with familial dilated cardiomyopathy by whole-exome sequencing

目的对一扩张型心肌病(dilated cardiomyopathy,DCM)家系行全基因组外显子测序以寻找该家系的致病基因。方法收集在复旦大学附属中山医院就诊的一位DCM患者及其家系成员的临床资料,采集相关家系成员外周血并抽提DNA,对该家系5名成员行全基因组外显子测序,寻找致病基因,用Sanger测序对家系其他成员进行验证。结果通过对家系患者与正常人测序结果比对分析,同时经过多个生物数据库数据过滤,发现LMNA基因6号外显子上存在的杂合突变c.961 C>T(p.Arg321Ter)为该家系的可能致病基因突变。LMNAc.961 C>T无义突变导致LMNA编码蛋白质过程提前终止,相应蛋白质功能异常,进而导致该家系中此突变基因的携带者出现心功能异常。结论本研究应用全基因组外显子测序从一DCM家系中发现其致病基因及突变位点:LMNAc.961 C>T(p.Arg321Ter),突变导致该家系相关成员心功能异常。此位点在汉族人群中尚属首次报道。

Objective T o identify the disease-causing gene in a Chinese pedigree with familial dilated cardiomyopathy(DCM)by whole-exome sequencing.Methods After collecting the clinical data and extracting the whole blood genomic DNA of the 5 family members form a Chinese DCM pedigree,whole-exome sequencing was performed to search the causative genes.Familial co-segregation analysis among the pedigree was subsequently confirmed by traditional Sanger sequencing.Results We performed whole exome sequencing(W ES)on representative affected individuals and unaffected familial members from this pedigree.After comparison with variants identified in affected individuals and unaffected individuals,along with previously reported genetic mutations associated with DCM,we found that a heterozygous variant c.961C>T(p.Arg321Ter)in exon 6 of the LMNA gene in affected individuals matched the criteria to be the potential disease-causing gene,which was confirmed by Sanger sequencing.This stop-gain mutation leads to only a small part of LMNA-coding protein expressed,therefore we concluded that LMNA c.961C>Tshould be the causative mutation for this familial DCM case.Conclusions The nonsense mutation c.961C>T in gene LMNA identified by whole-exome sequencing might be the pathogenic mutation in this DCM pedigree.