【摘要】 目的 分析2例疑似Meckel-Gruber综合征(MKS)胎儿及其父母的临床资料，探讨其基因突变特点。方法 2021年3月河南省人民医院进行遗传咨询的2次孕育疑似MKS胎儿的夫妇，收集胎儿母亲孕育史及孕期2个胎儿的超声声像资料，记录胎儿肾囊肿、颅脑结构异常、颜面部结构异常、羊水量等情况。采集父母外周血及2个胎儿皮肤组织，提取基因组DNA,采用染色体微阵列分析法检测100 kb以上的微重复/微缺失，与人类基因组结构变异数据库、DECIPHER等数据库进行比对；采用高通量测序法对胎儿2进行全外显子组测序，确定基因突变位点，采用PCR-Sanger测序法对胎儿1及其父母进行验证。应用生物信息学软件预测突变位点的致病性，并对突变位点的保守性进行分析。依据ACMG指南对突变位点进行分级。结果 胎儿母亲孕4产0,2次孕育MKS胎儿，2次胎儿停止发育。胎儿1、2均有颅脑结构异常、双侧多囊肾的MKS典型特征，胎儿1伴颜面部结构异常、羊水过少。胎儿1、2及其父母均未检出100 kb以上的染色体微重复/微缺失。胎儿1、2均存在TMEM67基因(NM＿153704)c.978+1G>A及c.1175C>G(p.Pro392Arg)杂合突变，其中c.978+1G>A均来源于胎儿父亲，为剪接位点突变，ACMG分级为致病；c.1175C>G均来源于胎儿母亲，为错义突变，ACMG分级为可能致病。Unipro UGENE软件分析结果显示TMEM67基因c.1175位点在6个物种中均高度保守，SIFT、Polyphen、Mutationtaster软件分析结果显示c.1175C>G突变有致病性。结论 TMEM67基因(NM＿153704)c.978+1G>A及c.1175C>G(p.Pro392Arg)复合杂合突变是该夫妇反复孕育MKS胎儿的遗传学病因。更多还原

【Abstract】 Objective To analyze the clinical data of two fetuses with suspected Meckel-Gruber syndrome(MKS)and their parents,and to investigate the characteristics of gene mutation.Methods One couple with two suspected MKS fetuses received genetic counseling in Henan Provincial People’s Hospital in March 2021.The pregnancy history of the mother and ultrasound image data of her two fetuses during pregnancy were collected,and the fetal renal cysts,brain structure abnormalities,facial structure abnormalities,and amniotic fluid volume were recorded.Genomic DNA was extracted from the peripheral blood of the parents and the skin tissues of two fetuses.Microduplications/deletions above100kb were detected by chromosome microarray analysis,and were compared with Human Genome Variation and DECIPHER database.The whole exome of fetus 2was sequenced by high-throughput sequencing to determine the gene mutations,and fetus 1and their parents were verified by PCR-Sanger sequencing.Bioinformatics software was used to predict the pathogenicity of mutations and to analyze the conserved nature of mutation sites.The mutations were graded and evaluated for pathogenicity according to ACMG guidelines.Results The mother experienced 4pregnancies,in which2fetuses were diagnosed with MKS,and the other two fetuses ceased development.The typical characteristics of MKS infetus 1 and 2included brain structure abnormalities and polycystic kidneys.Fetus 1 was complicated with facial structure abnormality and oligoamniotic fluid.No chromosome deletion/duplication of above 100kb was detected in fetus1and 2and their parents.Compound heterozygous variants c.978+1G>A and c.1175C>G (p.Pro392Arg)in TMEM67(NM＿153704)were detected in fetus 1and 2,in which c.978+1G>A was from the father,which was a splice site mutation and was rated as pathogenic by ACMG;c.1175C>G was derived from the mother and was a missense mutation with ACMG rating as likely pathogenic.Unipro UGENE software indicated that TMEM67 gene c.1175 was highly conserved in 6 species.Meanwhile,SIFT,Polyphen and Mutationtaster softwares showed that TMEM67 gene c.1175C>G was pathogenic.Conclusion The compound heterozygous variants c.978+1G>A and c.1175C>G(p.Pro392Arg)in TMEM67(NM＿153704)gene may be the genetic pathogenicity for the pedigree with MKS.更多还原