目的 探讨全外显子测序技术在具有原发性免疫缺陷(PID)患儿夭折史但无先证者的夫妻双方隐性遗传病携带推断分析中的应用。 方法 收集2017年2月至2021年12月就诊于河南省人民医院因有疑似PID患儿生育史进行遗传学检查的4对夫妻的临床资料。对夫妻双方外周血样进行全外显子测序(WES)，就候选变异用Sanger测序或荧光定量PCR进行验证，并进一步对家系中的胎儿进行产前诊断。 结果 WES共检出6个与病史相关的致病或疑似致病的基因变异，包含有IL2RG、BTK、CYBB、DUOX2等基因，变异类型包括点变异、小片段缺失及外显子缺失等。其中DUOX2基因c.1265G>A、c.3329G>A，IL2RG基因c.676C>T为已报道致病性变异。IL2RG基因Exon5_8del、BTK基因c.184_185delAC、CYBB基因c.472A>T既往未见报道。根据美国医学遗传学与基因组学学会变异评级指南，IL2RG基因Exon5_8del、BTK基因c.184_185delAC、CYBB基因c.472A>T评级均为可能致病性变异(PVS1＋PM2_Supporting＋PP4)。其中3对夫妻再次妊娠后进行了产前诊断，结果显示胎儿BTK基因c.184_185、CYBB基因c.472、IL2RG基因c.676位点均为野生型，胎儿出生1年后随访未发现异常。 结论 全外显子组测序是具有免疫缺陷患儿夭折史夫妻双方隐性遗传病携带情况推断分析的一种重要手段，可提高阳性检出率。 Objective To explore the value of whole exome sequencing for the inferential analysis of recessive genetic disease carrier status for couples with a child died of Primary immunodeficiency (PID). Methods Clinical data was collected from four couples with a childbearing history of PID who had sought genetic counseling and undergone genetic testing at Henan Provincial People′s Hospital from February 2017 to December 2021. Whole exome sequencing (WES) was performed on both partners of each couple, and candidate variants were validated by Sanger sequencing and fluorescent quantitative PCR. Prenatal diagnosis was conducted on fetuses of these couples after confirming the variants. Results A total of six variants were detected in four genes including IL2RG, BTK, CYBB, and DUOX2. Among these, the c.1265G>A and c.3329G>A variants of theDUOX2 gene and the c. 676C>T variant of theIL2RG gene were previously known as pathogenic variants. On the other hand, the Exon5_8del variant of the IL2RG gene, the c. 184_185delAC variant of the BTK gene, and the c. 472A>T variant of theCYBB gene were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics, the IL2RG: Exon5_8del, BTK: c. 184_185delAC and CYBB: c. 472A>T variants were classified as likely pathogenic (PVS1+ PM2_Supporting+ PP4).Prenatal diagnosis was conducted for three couples during their subsequent pregnancies, and the results revealed that the fetuses had the wild-type genotypes at the c. 184_185 position of theBTK gene, the c. 472 position of the CYBB gene, and the c. 676 position of the IL2RG gene. Follow-up examinations one year after birth has found no abnormality in the infants. Conclusion WES is an important tool to infer and analyze the carryier status for couples who had given births to children died of PID and improve the positive detection rate.
Application of whole exome sequencing for the inferential analysis of recessive genetic disease carrier status for couples with a child died of Primary immunodeficiency
Objective To explore the value of whole exome sequencing for the inferential analysis of recessive genetic disease carrier status for couples with a child died of Primary immunodeficiency (PID). Methods Clinical data was collected from four couples with a childbearing history of PID who had sought genetic counseling and undergone genetic testing at Henan Provincial People′s Hospital from February 2017 to December 2021. Whole exome sequencing (WES) was performed on both partners of each couple, and candidate variants were validated by Sanger sequencing and fluorescent quantitative PCR. Prenatal diagnosis was conducted on fetuses of these couples after confirming the variants. Results A total of six variants were detected in four genes including IL2RG, BTK, CYBB, and DUOX2. Among these, the c.1265G>A and c.3329G>A variants of theDUOX2 gene and the c. 676C>T variant of theIL2RG gene were previously known as pathogenic variants. On the other hand, the Exon5_8del variant of the IL2RG gene, the c. 184_185delAC variant of the BTK gene, and the c. 472A>T variant of theCYBB gene were unreported previously. Based on the guidelines from the American College of Medical Genetics and Genomics, the IL2RG: Exon5_8del, BTK: c. 184_185delAC and CYBB: c. 472A>T variants were classified as likely pathogenic (PVS1+ PM2_Supporting+ PP4).Prenatal diagnosis was conducted for three couples during their subsequent pregnancies, and the results revealed that the fetuses had the wild-type genotypes at the c. 184_185 position of theBTK gene, the c. 472 position of the CYBB gene, and the c. 676 position of the IL2RG gene. Follow-up examinations one year after birth has found no abnormality in the infants. Conclusion WES is an important tool to infer and analyze the carryier status for couples who had given births to children died of PID and improve the positive detection rate.
万方数据
