基因组拷贝数变异检测技术在7617例孕中期血清学筛查异常孕妇产前诊断中的应用

Application of genomic copy number variation detection technology in prenatal diagnosis of 7617 pregnant women with serological screening abnormalities during the second trimester of pregnancy

目的分析血清学筛查异常胎儿基因组变异特征,探讨基因组拷贝数变异检测技术应用于血清学筛查异常胎儿产前诊断中的价值。方法选取单纯因唐氏血清学筛查异常,行羊膜腔穿刺进行产前诊断的单胎孕妇7617例为研究对象。依据血清学筛查结果分为高风险、临界风险、单项指标异常,采用CMA和CNV-Seq进行羊水细胞基因组拷贝数变异检测并结合羊水细胞核型分析进行产前诊断,采用门诊复诊结合电话问询进行妊娠结局随访。结果7617例羊水标本中,CMA和CNV-Seq共检测出非整倍体138例(1.81%),羊水细胞核型分析额外检出9例非整倍体嵌合体,检出203例胎儿携带致病和可能致病CNV,437例胎儿携带意义不明拷贝数变异(5.7%),总体异常检出率为10.33%。CMA和CNV-Seq在三组间检出非整倍体分别为123例(2.0%)、13例(1.3%)、2例(0.4%),检出率存在明显差异(χ^(2)=7.469,P=0.024);致病和可能致病CNV在3组间分别检出163例(2.6%)、24例(2.6%)、16(3.3%),检出率无明显差异(χ^(2)=0.764,P=0.682)。CMA与CNVseq两种方法P/LP CNV检出率分别为2.9%(108/3729)、2.4%(95/3888),差异无统计学意义(χ^(2)=1.504,P=0.22)。检出率较高的致病和可能致病CNV分别为Xp22.31微缺失、16p13.11微缺失/微重复、22q11.21微缺失/微重复。妊娠结局随访,携带致病和可能致病CNV胎儿,59例终止妊娠,112例出生的胎儿中有32例出现异常临床表现;携带意义不明CNV胎儿,11例发生了非医学需要的终止妊娠,322例出生的胎儿中4例出现异常临床表现。结论拷贝数变异检测技术与核型分析相比可提高致病和可能致病CNV的检出率,针对唐氏血清学筛查异常群体,CMA或CNV-Seq可作为首选的产前诊断方法。

Objective To analyze the genomic variation characteristics of fetal with abnormal serological screening,and to further explore the value of copy number variation(CNV)detection technology in prenatal diagnosis of fetal with abnormal serological screening.Methods 7617 singleton pregnant women who underwent amniocentesis for prenatal diagnosis solely due to abnormal Down’s serological screening were selected.According to the results of serological screening,the patients were divided into high risk group,borderline risk group and single abnormal multiple of median(MOM)group.CMA and CNV-Seq were used to detect the copy number variation of amniotic fluid cell genomic DNA and combined with amniotic fluid cell karyotype analysis for prenatal diagnosis.Outpatient revisit combined with telephone inquiry was used for postnatal follow-up.Results Among 7617 amniotic fluid samples,aneuploidy was detected in 138cases(1.81%)by CMA and CNV-Seq,9 cases of aneuploid chimerism were detected by amniotic fluid cell karyotype analysis,and 203 cases of fetus carrying pathogenic and likely pathogenic CNV(P/LP CNV)were detected,the variant of uncertain significance(VUS)was detected in 437 cases(5.7%),the overall abnormal detection rate was 10.33%.The detection rate of aneuploidy by CMA and CNV-Seq in three group were 123 cases(2.9%),13 cases(1.3%)and 2 cases(0.4%),respectively,and showing no significant difference(χ^(2)=7.469,P=0.024).The detection rate of pathogenic and likely pathogenic CNV in three group were 163cases(2.6%);24 cases(2.6%)and 16 cases(3.3%),respectively,and showing no significant difference(χ^(2)=0.764,P=0.682).The CMA reported 2.9%(108/3729)P/LP CNV,and CNV-seq reported 2.4%(95/3888)P/LP CNV,both tests showed similar detective capabilities(χ^(2)=1.504,P=0.22).The most popular P/LP CNV in this cohort were Xp22.31 microdeletion,16p13.11 microduplication/microdeletion,22q11.21 microduplication/microdeletion.In fetuses with P/LP CNV CNV,59 fetuses were terminated pregnancy,and 32 of 112 fetuses born had abnormal clinical manifestations.Non-medically necessary termination of pregnancy occurred in 11 fetuses carrying VUS CNV,322 fetuses carrying VUS CNV were born,4 of them presented abnormal clinical manifestations.Conclusion Compared with the traditional chromosome karyotype,CMA and CNV-Seq can improve the detection rate of pathogenic and likely pathogenic CNV.CMA and CNV-seq can be used for first tier diagnosis of pregnant women in the general population with abnormal Down’s serological screening.