2个脆性X综合征家系的产前基因诊断与遗传咨询  

Prenatal diagnosis and genetic counseling of fragile X syndrome in two pedigrees

作　　者：徐雪琴 徐云芝 李焕铮 徐晨阳 唐少华 XU Xueqin;XU Yunzhi;LI Huanzheng;XU Chenyang;TANG Shaohua(Central Laboratory,Wenzhou Central Hospital,Wenzhou,Zhejiang 325000,China)

机构地区：[1]温州市中心医院检验科,浙江温州325000

出　　处：《中国优生与遗传杂志》2021年第9期1306-1309,共4页Chinese Journal of Birth Health & Heredity

基　　金：浙江省基础公益研究计划项目(LGF21H260005)。

摘　　要：目的对疑有脆性X综合征(FXS)家族史的孕妇及其家系成员进行脆性X智力障碍1(FMR1)基因诊断,并对其当前所怀胎儿进行产前诊断及遗传咨询。方法对温州市中心医院产科遗传咨询门诊就诊的2例孕妇及其儿子抽取静脉血1~2 mL,孕妇采集羊水20 mL,提取DNA,采用聚合酶链反应(PCR)检测CGG重复次数,MS-MLPA试剂盒检测男性FMR1基因的CpG岛的甲基化水平。结果孕妇1和孕妇2均有一条X染色体CGG重复>200次,其子的一条X染色体FMR1 CGG重复>200次。孕妇1行羊膜腔穿刺后羊水检测结果显示FMR1基因CGG全突变,经遗传咨询后引产。孕妇2的胎儿不存在FXS高风险,继续妊娠。结论 PCR联合MS-MLPA技术可以成为FXS的一种产前分子诊断手段,避免患儿出生。Objective To provide prenatal diagnosis and genetic counseling for two athigh-risk pregnant women or with a suspected family history fragile X syndrome(FXS) by genetic screening of fragile X mental retardation 1(FMR1) gene.Methods This study was conducted on two pregnant women and their sons who received outpatient treatment in Wenzhou Central Hospital. Genomic DNA was extracted from peripheral blood samples and amniotic fluid samples of the pregnant women and 2 of their family members. CGG repeat size in FMR1 gene were detected by PCR. Methylation status of the promoters of FMR1 gene were analyzed by MS-MLPA. Results The pregnant women No.1 and No.2 were full mutation carriers with over 200 CGG repeats in FMR1 gene at chromosome X, and their sons had full mutations with over 200 CGG repeats in FMR1 gene. Fetus of No.1 had a full mutation with over 200 CGG repeats in FMR1 gene. After genetic counseling, No.1 decided terminate the pregnancy. No.2 continued to pregnancy as her fetus was free of FXS risk. Conclusions The combination of PCR and MS-MLPA can provide a method for the prenatal diagnosis of FXS to avoid birth defects.

关 键 词：脆性X综合征 CGG重复 甲基化 产前诊断 遗传咨询 

分 类 号：R714.5[医药卫生—妇产科学]