无创 DNA产前检测技术在诊断胎儿唐氏综合征中的应用

摘要

Objective:To explore application value of non-invasive prenatal test in screening of Down ' s syndrome through using high-throughput sequencing technique to test fetal free DNA in maternal Peripheral blood. Methods:A total of 115 cases with singleton pregnancies, whose fetuses were at high risk of Down's syndrome by prenatal serological and B ultrasound screening, were se-lected. Their plasma was sampled for the non-invasive prenatal DNA test, and amniotic fluid was also collected for the chromosome karyotype analysis, wherein the result of the latter was used as a "gold standard". The results of the non-invasive prenatal DNA test and the chromosome karyotype analysis were compared and analyzed. The percentage of fetal DNA in the total maternal circulating DNA was inferred by calculating the number of reads mapped to Y chromosome. Results: In the 115 cases, there were 15 cases judged as high-risk Down's syndrome for their fetuses and 100 cases judged as low-risk Down's syndrome for their fetuses through the non-inva-sive prenatal DNA tes;and in the 100 cases, their G band karyotypes were all normal, however, in the 15 case, 14 cases were finally diagnosed as Down's syndrome through the chromosome karyotype analysis. Conclusions:The new non-invasive prenatal DNA test for Down's syndrome has the same sensitivity and specificity with the chromosome karyotype analysis of the aminotic cells; it has the ad-vantages of safety, non-invasion, and high throughput, therefore, it has a wider clinical application value. However, a further amnio-centesis confirmation is definitely required for the high-risk case identified by the non-invasive prenatal test.%目的：利用高通量测序技术检测孕妇外周血中的胎儿游离 DNA,探讨唐氏综合征无创产前检测的应用价值。方法：选择唐氏综合征高风险而进行确定诊断的单胎孕妇115例,用孕妇血浆进行无创DNA产前检测。同时,采集羊水,进行染色体核型分析,并以该结果为“金标准”,将无创DNA产前检测结果与羊水细胞核型诊断结果作比较分析。根据Y染色体比对的reads数目,计算孕妇外周血中胎儿DNA的含量。结果：115例孕妇经新型无创DNA产前筛查判定胎儿为唐氏综合征高风险15例,唐氏综合征低风险100例；结果显示100例新型无创DNA产前检测为唐氏综合征低风险的胎儿,其染色体常规G显带分析均为正常核型；15例无创DNA产前检测为唐氏综合征高风险样本中,14例羊水染色体结果确诊为唐氏综合征,1例羊水染色体分析为正常。结论：新型无创DNA产前检测技术的灵敏度和特异度与羊水细胞核型分析结果高度一致,其安全、无创及高通量的优势具有更为广泛的临床应用价值。但DNA检测明确有21-三体综合征高风险的孕妇,也必须进行羊水穿刺进一步确诊。