胚胎植入前遗传学诊断应用于SLC26A4致聋突变家庭的临床研究

Application of Preimplantation Genetic Diagnosis in Families with SLC26A4 Gene Mutation Related Hearing Loss for Normal Hearing Offspring

目的研究携带SLC26A4致病基因突变的家庭中,胚胎植入前遗传学诊断(PGD)技术在帮助实现孕育听力正常后代、阻断耳聋基因垂直传递中的效果。方法采用单细胞全基因组扩增技术(MALBAC)、高通量测序技术及SNP分型技术,对5组夫妻双方均携带SLC26A4基因已知致病突变的家庭进行胚胎植入前遗传学诊断,挑选健康胚胎进行移植,在孕中期行羊水穿刺产前诊断基因型,新生儿出生后进行听力筛查。结果5组家庭中,3组家庭经PGD成功受孕,其中家庭1、家庭2已生育听力正常的新生儿,家庭4仍在妊娠期;家庭3经一次PGD形成的胚胎均携带耳聋基因,后选择自然受孕,经产前诊断检测胎儿基因型为单杂合突变携带;家庭5经促排卵后未成功排卵而退出研究。结论1.对于明确致病基因的家庭,PGD技术能够阻断耳聋基因的垂直传播,帮助生育健康胎儿;2.如果女方高龄,由于卵巢储备逐渐下降、对外源性促性腺激素的反应能力下降等原因,在PGD过程中失败风险高。

Objective To report application of preimplantation genetic diagnosis(PGD)in helping families carrying pathogenic SLC26A4 mutations acquire offspring with normal hearing by blocking vertical transmission of deafness genes.Methods Multiple annealing and looping-based amplification cycles(MALBAC),high-throughput sequencing,and SNP typing technologies were used to carry out preimplantation genetic diagnosis in 5 couples in which both spouses carried a known pathogenic mutation of the SLC26A4 gene,for selection of healthy embryos.Amniotic fluid puncture and prenatal genotype diagnosis were performed during the second trimester,and the newborn was hearing screened af-ter birth.Results Among the 5 couples,pregnancy guided by PGD was successfully in 3 couples,of whom 2 gave birth to newborns with normal hearing,and 1 is still in pregnancy.For one couple,all embryos formed were found to carry deafness gene mutations by PGD.They subsequently elected natural conception,and prenatal diagnosis showed a single heterozygous mutation.Ovulation induction was not successful in the last couple,who then exited the study.Conclusions 1.In couples carrying pathogenic genes,PGD technologies can help block vertical transmission of deafness genes and facilitate families with such genes to acquire healthy newborns;2.In women at an advanced age with decreased ovarian reserve and poor response to exogenous gonadotropins stimulation,the risk for failure of in vitro fertilization and therefore PGD is relatively high.