自然流产患者1 065例的遗传学病因及其相关因素的分析

Analysis of genetic etiology and related factors in 1065 women with spontaneous abortions

目的探讨1065例自然流产患者的遗传学病因及其相关因素。方法选择2018年1月至2021年12月于南京鼓楼医院产前诊断中心就诊的1065例自然流产患者为研究对象。采集患者的绒毛组织或胎儿皮肤组织,用染色体微阵列分析(CMA)对其基因组DNA进行检测。选取10对CMA检测未见异常的非体外受精-胚胎移植(IVF-ET)妊娠、既往无活产分娩史且无子宫结构畸形的早期复发性流产夫妇,采集其外周静脉血样,进行家系全外显子组测序(trio-WES),并通过Sanger测序对结果进行验证,并对候选变异进行生物信息学分析。采用多因素非条件Logistic回归分析法,对可能影响流产组织中染色体异常的因素进行分析,包括夫妇双方的年龄、既往自然流产的次数、是否进行IVF-ET以及有无活产分娩史等。不同流产次数的低龄和高龄患者早期流产组织染色体非整倍体发生率的比较采用线性趋势χ^(2)检验。结果在1065份自然流产组织中,CMA共检出染色体异常570例(53.5%),其中染色体非整倍体489例(45.9%),致病/可疑致病拷贝数变异(CNVs)36例(3.4%)。在10对夫妇中,trio-WES检测在2对夫妇的流产组织中分别发现1个纯合变异和1个复合杂合变异,均遗传自亲代;在2对夫妇的自然流产组织中分别发现1个疑似致病变异。多因素非条件Logistic回归分析显示,孕妇年龄是流产组织染色体异常的独立风险因素(OR=1.122,95%CI:1.069-1.177,P<0.001),既往流产次数和IVF-ET妊娠则是其独立保护因素(OR=0.791、0.648,95%CI:0.682-0.916、0.500-0.840,P=0.002、0.001),配偶年龄和活产分娩史并非其独立风险因素(P>0.05)。在低龄患者的流产组织中,非整倍体的发生率随既往自然流产次数的增加而下降(χ^(2)=18.051,P<0.001)。在高龄患者的流产组织中,非整倍体的发生率则与既往自然流产的次数无显著相关性(P>0.05)。结论自然流产的遗传学病因以染色体非整倍体为主,而CNVs与基因变异也值得重视。孕妇的年龄、既往流产的次数及IVF-ET妊娠与流产组织中的染色体异常密切相关。

Objective To explore the genetic etiology and related factors in 1065 women with spontaneous abortions.Methods All patients have presented at the Center of Prenatal Diagnosis of Nanjing Drum Tower Hospital from January 2018 to December 2021.Chorionic villi and fetal skin samples were collected,and the genomic DNA was assayed by chromosomal microarray analysis(CMA).For 10 couples with recurrent spontaneous abortions but normal CMA results for abortive tissues,non-in vitro fertilization-embryo transfer(IVF-ET)pregnancies and no previous history of live births and no structural abnormalities of the uterus,peripheral venous blood samples were collected.Genomic DNA was subjected to trio-whole exome sequencing(trio-WES).Candidate variants were verified by Sanger sequencing and bioinformatics analysis.Multifactorial unconditional logistic regression analysis was carried out to analyze the factors that may affect chromosomal abnormality in spontaneous abortions,such as the age of the couple,number of previous spontaneous abortions,IVF-ET pregnancy and history of live birth.The incidence of chromosomal aneuploidies in spontaneous abortions during the first trimester was compared in young or advanced-aged patients by chi-square test for liner trend.Results Among the 1065 spontaneous abortion patients,570 cases(53.5%)of chromosomal abnormalities were detected in spontaneous abortion tissues,which included 489 cases(45.9%)of chromosomal aneuploidies and 36 cases(3.4%)of pathogenic/likely pathogenic copy number variations(CNVs).Trio-WES results have revealed one homozygote variant and one compound heterozygote variants in two pedigrees,both of which were inherited from the parents.One likely pathogenic variant was detected in the patient from two pedigrees.Multifactorial unconditional Logistic regression analysis suggested that age of patient was an independent risk factor of chromosome abnormalities(OR=1.122,95%CI:1.069-1.177,P<0.001),the number of previous abortions and IVF-ET pregnancy were independent protective factors for chromosomal abnormalities(OR=0.791,0.648;95%CI:0.682-0.916,0.500-0.840;P=0.002,0.001),whilst the age of husband and history of live birth were not(P>0.05).The incidence of aneuploidies in the abortive tissues has decreased with the number of previous spontaneous abortions in young patients(χ^(2)=18.051,P<0.001),but was not significantly correlated with the number of previous spontaneous abortions in advanced-aged patients with spontaneous abortions(P>0.05).Conclusion Chromosomal aneuploidy is the main genetic factor for spontaneous abortion,though CNVs and genetic variants may also underlie its genetic etiology.The age of patients,number of previous abortions and IVF-ET pregnancy are closely associated with chromosome abnormalities in abortive tissues.