高通量测序技术在甲基丙二酸血症基因诊断中的应用及其局限性  

Application and the limitation of next generation sequencing for the diagnosis of methylmalonic academia

作　　者：苏利沙[1] 胡爽 孔祥东[1] Su Lisa;Hu Shuang;Kong Xiangdong(Genetics and Prenatal Diagnosis Center,Department of Obstetrics and Gynecology,the First Affiliated Hospital of Zhengzhou University,Zhengzhou,Henan 450052,China)

机构地区：[1]郑州大学第一附属医院妇产科遗传与产前诊断中心,450052

出　　处：《中华医学遗传学杂志》2021年第8期740-744,共5页Chinese Journal of Medical Genetics

基　　金：国家重点研究发展计划(2018YFC1002203)。

摘　　要：目的对31个甲基丙二酸血症家系进行相关致病基因检测,以明确基因诊断并为家系产前诊断提供依据。方法针对2017年1月到2019年6月到郑州大学第一附属医院门诊进行咨询的31个甲基丙二酸血症家系,采用高通量测序技术对先证者进行基因变异检测,对致病/疑似致病基因变异进行Sanger测序验证并对先证者父母进行Sanger测序以追踪变异的来源,对只检测到MMACHC基因杂合变异的先证者用实时荧光定量PCR对MMACHC基因外显子缺失/重复进行检测。针对检测到致病/疑似致病变异的25个家系,对其中8名孕妇进行产前诊断。结果25个家系检测到致病/疑似致病基因变异(检出率80.65%),3个家系检测到MMACHC基因存在外显子杂合缺失合并杂合变异(检出率9.67%),总检出率90.32%,其中18个家系为MMACHC基因变异(3个家系存在外显子杂合缺失,共12种基因变异,其中1个新变异),7个家系为MUT基因复合杂合变异(共11种基因变异,2个新变异),1个家系为HCFC1 c.3356C>T(p.Thr1119Ile)半合子变异所致甲基丙二酸尿症伴同型半胱氨酸尿症Cb1X型,1个家系为PCCB基因复合杂合变异所致丙酸血症,1个家系为SUCLG1基因纯合变异所致线粒体DNA缺失综合征9型。产前诊断结果提示4名胎儿未检测到MMA相关基因致病变异,1例胎儿为MUT基因杂合变异携带者,3例胎儿为MACHC基因复合杂合变异患儿。结论高通量测序技术可以高效、准确筛选出甲基丙二酸血症及其他代谢病相关致病基因变异,但存在不能检测出致病基因外显子拷贝数异常的局限,其联合实时荧光定量PCR对致病基因外显子拷贝数进行检测能够提高MMA基因变异检出率,明确基因诊断并为相关家系的产前诊断提供指导。Objective To identify genetic variants among patients with methylmalonic acidemia and provide genetic evidence for prenatal diagnosis.Methods Thirty-one probands and their parents were subjected to next generation sequencing(NGS).Suspected variants were verified by Sanger sequencing.Results 25 probands or their parents were found to harbor previously known pathogenic or likely pathogenic variants,and three probands were found to carry heterozygous MMACHC exonic deletion.The overall diagnostic yield was 90.32%.Conclusion NGS can improve the detection rate for methylmalonic acidemia for its accuracy and efficiency,yet the detection of exonic deletion is required to further improve the diagnostic yield.The identification of specific variants provided evidence for prenatal diagnosis.

关 键 词：甲基丙二酸血症 高通量测序 MMACHC基因 

分 类 号：R725.8[医药卫生—儿科] R440[医药卫生—临床医学]