无创DNA检测在双胎唐氏综合征产前筛查中应用价值研究

Application of noninvasive DNA test in prenatal screening of Down's syndrome in twin pregnancies

目的探讨无创DNA检测在双胎唐氏综合征产前筛查和诊断中的临床应用价值。方法收集2015年6月至2016年6月在天津市妇女儿童保健中心门诊进行围产保健的双胎孕妇共445例,进行血清标志物(AFP+β-h CG)二联指标检测,同时运用Illumina Hiseq2000测序技术对孕妇外周血中的游离DNA片段(含胎儿游离DNA)进行高通量测序及统计分析,对筛查高风险者进一步通过羊水穿刺进行染色体核型分析,低风险者随访至产后。结果行唐氏综合征血清学筛查392例,高风险31例,阳性率和假阳性率分别为7.91%、7.14%,检出率75%,特异度93.27%;无创DNA检测442例,唐氏综合征阳性孕妇5例,阳性率和假阳性率分别为1.13%、0.23%,检出率100%,特异度99.77%。两种方法用于唐氏综合征产前筛查的差异有统计学意义(P<0.01)。结论无创DNA检测可应用于双胎孕妇唐氏综合征产前筛查,有效减少出生缺陷儿的出生。

Objective To investigate the clinical value of noninvasive DNA examination in prenatal screening and diagnosis of twin pregnancies with Down syndrome.Methods From June 2015 to June 2016 in the twin pregnant women of Tianjin Women＇s and Children＇s health center in the outpatient perinatal care in 445 cases,the serum markers（AFP ＋β-h CG）combined detection of two indexes,while the use of Illumina Hiseq2000 sequencing technology on peripheral blood of pregnant women free DNA fragment（containing fetal DNA）analysis of high-throughput sequencing and statistics,screening of high risk of further amniocentesis chromosome analysis,low risk of follow-up to postpartum.Results Prenatal screening for Down＇s syndrome in 392 cases,31 cases with high risk,and false positive rate were 7.91%,7.14%,the detection rate of 75%,a specificity of 93.27%;noninvasive detection of 442 cases of DNA,5 cases of Down syndrome in pregnant women with positive,and false positive rate were 1.13%,0.23%,detection rate 100%,the specificity was 99.77%. There was a significant difference between the two methods in the prenatal screening for Down＇s syndrome（P〈0.01）.Conclusion Noninvasive DNA detection can be used in prenatal screening of fetal Down＇s syndrome in twin pregnancies,reducing the incidence of birth defects.