无创产前基因检测在胎儿性染色体疾病筛查中的应用

目的探讨无创产前基因检测(non-invasive prenatal genetic testing,NIPT)在胎儿性染色体疾病中的临床价值。方法统计深圳市第二人民医院2016年3月至2019年6月行NIPT的16119例单胎孕妇中提示21-三体、18-三体、13-三体、性染色体异常和其他染色体异常的阳性率;对比2016年3月至2019年6月NIPT示“胎儿性染色体异常”与本院染色体核型结果。结果①NIPT对21-三体,18-三体,13-三体,性染色体异常和其他染色体异常筛查的阳性率分别为0.42%(68/16119),0.10%(16/16119),0.07%(11/16119),0.38%(61/16119)和0.22%(36/16119)。②47例“NIPT示胎儿性染色体异常”者中,确诊为性染色体疾病者26例,阳性预测值55.32%。其中,NIPT对胎儿性染色体数目偏多的阳性预测值为91.30%(21/23),对胎儿性染色体数目偏少的阳性预测值20.0%(4/20),对胎儿性染色体数目异常的阳性预测值25.0%(1/4)。结论NIPT可作为胎儿性染色体疾病的筛查方法,但由于其对性染色体偏少和性染色体数目异常的假阳性率较高,检测阳性者仍需要做侵入性产前诊断确诊。

Application of non-invasive prenatal genetic testing in screening of fetal sex chromosomal abnormalities

Objective To investigate the clinical value of noninvasive prenatal genetic testing(NIPT)in fetal sex chromosomal diseases by statistics of the positive rate of fetal sex chromosomal abnormalities with NIPT in our hospital and comparing the results of NIPT and amniocentesis.Methods From March 2016 to June 2019,16119 single pregnant women who underwent NIPT in our hospital were studied.The positive rates of patients with trisomy 21,trisomy 18,trisomy 13,sex chromosomal abnormalities and other chromosomal abnormalities were recorded.“NIPT suggestive sex chromosomal abnormality”from march 2016 to June 2019 and their karyotypes in our hospital were compared.Results①The positive rates of NIPT for trisomy 21,trisomy 18,trisomy 13,sex chromosomal abnormalities and other chromosomal abnormalities were 0.42%(68/16119),0.10%(16/16119),0.07%(11/16119),0.38%(61/16119)and 0.22%(36/16119)respectively.②Among the 47 pregnant women because of“NIPT suggestive sex chromosomal abnormalities”,26 cases of them were diagnosed as different sex chromosomal diseases,with a positive predictive value of 55.32%.Among them,the positive predictive value of NIPT for high number of sex chromosomes was 91.30%(21/23).The positive predictive value of NIPT for low sex chromosomes number was 20.0%(4/20).The positive predictive value of NIPT for abnormal number of fetal sex chromosomes was 25.0%(1/4).Conclusion NIPT can be used as a screening method for sex chromosomal diseases.Because of its high false positive rate in low sex number of chromosomes and abnormal number of sex chromosomes,invasive prenatal diagnosis is still needed for those who are positive.