外显子测序技术在一个尿道下裂家系基因分析及产前诊断中的应用

Exon sequencing and prenatal diagnosis of a hypospadias family

目的采用外显子测序(exon sequencing,ES)联合Sanger测序技术检测1个尿道下裂家系的致病基因,并对这一致病基因进行产前诊断。方法采集先证者及其父母的外周血,并提取DNA。对先证者的DNA进行性腺疾病相关基因的外显子测序找到致病基因,并针对该致病基因对先证者父母的DNA进行Sanger验证,明确是遗传自亲代。对先证者母亲再次妊娠的羊水标本提取DNA,采用Sanger测序对该致病基因行产前诊断。结果先证者SRD5A2(NM_000348):c.607G>A,P.(Gly203Ser)杂合突变及c.680G>A,P.(Arg227Gln)杂合突变组成的复合杂合突变。而其表型正常的母亲为SRD5A2(NM_000348):c.607G>A,P.(Gly203Ser)杂合突变;其表型正常的父亲为SRD5A2(NM_000348):c.680G>A,P.(Arg227Gln)杂合突变。先证者母亲再次妊娠产前诊断结果为SRD5A2(NM_000348):c.680G>A,P.(Arg227Gln)杂合突变。结论 ES联合Sanger测序可用于检测尿道下裂家系的致病基因及进行产前诊断。且此方法快速、准确、经济。

Objective To detect the pathogenetic genes of a hypospadias family using exon sequencing（ES） and Sanger sequencing for prenatal diagnosis. Methods The peripheral blood was collected from probands and their parents, and DNAs were extracted. The pathogenicity-related genes were found by ES of the DNAs related to the gonadal disease of the precursor, and the DNAs of the parents′ parents were verified by Sanger sequencing that they were clearly inherited from the parents. DNAs were extracted from the amniotic fluid samples of the proband mother again, and the Sanger gene was used for prenatal diagnosis. Results A compound heterozygous mutation of SRD5A2（NM_000348）： c.607G〉A, P.（Gly203Ser） and c.680G〉A, P.（Arg227Gln） heterozygous mutation were found in the proband. The normal phenotype of the mother was SRD5A2（NM_000348）： c.607G〉A, P.（Gly203Ser） heterozygous mutation, and the normal phenotype of the parent was SRD5A2（NM_000348）： c.680G〉A, P.（Arg227Gln） heterozygous mutation. The prenatal diagnosis of the proband mother was SRD5A2（NM_000348）： c.680G〉A and P.（Arg227Gln） heterozygous mutation. Conclusion ES combined with Sanger sequencing can be used to detect the pathogenic genes to diagnose families hypospadias prenatally and the method is fast, accurate and economical.