无创产前DNA筛查在胎儿染色体非整倍体基因检测中的临床应用

The clinical application of noninvasive prenatal DNA screening in fetal chromosome aneuploidy gene detection

目的:探讨无创产前DNA筛查(NIPT)在胎儿染色体非整倍体基因检测中的临床应用价值。方法:选择2015年5月-2016年12月在聊城市东昌府区妇幼保健院产前诊断中心进行无创产前DNA筛查孕妇,对筛查出的高风险病例进行羊膜腔穿刺或脐带血穿刺染色体核型分析和染色体微缺失微重复检测,确诊并追踪回访妊娠结局,对筛查结果为低风险孕妇进行追踪回访至产后12周。结果:在10 203例孕妇中筛查出高风险122例(1.2%),包括21-三体33例(0.3%),18-三体15例(0.2%),13-三体3例(0.03%),性染色体异常25例(0.3%),其他染色体异常46例(0.5%)。对筛查出染色体异常高风险孕妇进行羊膜腔穿刺或脐血穿刺进行确诊和追踪回访,21-三体假阳性率为0.02%,18-三体假阳性率为0.01%,13-三体假阳性率为0.03%。经过回访,10 203例孕妇中有1例假阴性。孕妇年龄分析,NIPT阳性率低的年龄段为26~35岁。对1例T18假阳性患者进行胎盘组织及脐带不同位点取样和脐血检测发现NIPT假阳性来源于胎盘组织。结论:孕妇外周血胎儿游离DNA产前检测对21-三体、18-三体有较高的特异性和准确性,而对性染色体和其他染色体的特异性和准确性较低。

Objective To explore the clinical application value of non invasive prenatal testing （NIPT） in fetal chromosome aneuploidy gene detection. Methods： A total of 10203 pregnant women in the prenatal diagnosis center of Dongchangfu district maternal and child health care hospital of Liaocheng city were randomly selected from May 2015 to December 2016. Amniocentesis or umbilical cord blood puncture were carried out in the pregnant women with high risk by NIPT screening, and the pregnancy outcomes of comfirmed cases were followed up. Meanwhile, the pregnant women with low risk by NIPT screening were also followed up to 12 weeks postpartum. Results： A total of 122 pregnant women with high risk （positive rate was 1.2%） were screened, which included 33 cases of trisomy 21 （positive rate was 0.3%）, 15 cases of trisomy 18 （positive rate was 0.2%）, 3 cases of trisomy 13 （positive rate was 0.03%）, 25 cases of sex chromosome abnormalities （positive rate was 0.3%）, and 46 cases of other chromosome abnormalities （positive rate was 0.5%）. For these pregnant women with high risk, chromosome abnormal amniotic cavity puncture or umbilical cord blood biopsy diagnosis were performed. It was found that the false positive rate of trisomy 21 was 0.02 %, the false positive rate of trisomy 18 was 0.01%, the false positive rate of trisomy 13 was 0.03%, and there was only 1 case with the false negative result. By analyzing the age of pregnant women, it was discovered that the low positive rate of NIPT was between the age of 26 and 35. Moreover, it was found that the T18 false positive was generated from the placental tissue. Conclusion： Peripheral cell free fetal DNA in prenatal testing for 21 trisomy syndrome and 18 trisomy syndromes has a high specificity and accuracy. However, the specificity and accuracy of sex chromosome and other chromosome was relatively low.