不同妊娠状态下孕妇外周血中游离胎儿DNA定量分析

目的对不同妊娠状态下孕妇外周血中游离胎儿DNA(f DNA)定量分析,确定其平均浓度及临床参考值范围,初步探讨在不同妊娠状态下母血中f DNA的浓度变化,为临床应用提供科学依据。方法从孕妇外周血浆中提取fDNA,用实时荧光定量聚合酶链反应(FQ-PCR)方法检测其中Y性别决定区的SRY基因。结果在正常早期的孕妇组38例血浆标本中有32例检测到SRY基因,其平均浓度149.25拷贝数/ml,参考值范围为33.28~265.22拷贝数/ml;在正常晚期的孕妇组32例血浆标本中全部检测到SRY基因,其平均浓度为212.14拷贝数/ml,参考值范围为142.76~281.52拷贝数/ml;在晚期患有子痫前期的孕妇30例血浆标本中全部检测到SRY基因,其平均浓度为678.70拷贝数/ml,参考值范围为595.01~726.40拷贝数/ml。实验数据用单因素方差分析,组间差异显著性检验用LSD-t检验。妊娠晚期孕妇血浆中f DNA的含量较妊娠早期升高,约为1.4倍,有统计学意义(P<0.01);晚期患子痫前期的孕妇血浆f DNA的水平是同期正常对照组的3.9倍,有统计学意义(P<0.01)。结论1.用FQ-PCR法最早在孕48天孕妇外周血中即可检测到fDNA。2.随着妊娠的进展孕妇血浆中f DNA的含量升高。3.晚期患子痫前期孕妇其血浆f DNA的水平是同期正常对照组的3.9倍,有统计学意义(P<0.01)。4.f DNA在进行无创伤性产前诊断中有重要价值。

Quantitative analysis of fetal cell-free DNA in maternal plasma at different pregnant conditions

Objective: Measure the concentration of fetal DNA in maternal plasma.Address the mean concentration and 95% confidence interval for parameter at different pregnant conditions.Methods:Fetal DNA was isolated from maternal plasma,SRY gene on the Y chromosome was measured by real-time Fluorescence Quantitative Polymerase Chain-reaction(FQ-PCR).Results:32 cases were detected SRY gene out of 38 cases at early pregnant carrying male fetuses.And fetal DNA is present in high concentrations in maternal plasma,reaching a mean and 95% confidence interval for parameter: 149.25Eq/ml,33.28~265.22Eq/ml;212.14Eq/ml,142.76~281.52Eq/ml and 678.70Eq/ml,595.01~726.40Eq/ml in early normal pregnancy,in late normal pregnancy and in late abnormal pregnancy respectively.The concentrations of fetal DNA are higher in late gestation than in early gestation,about 1.4-times(LSD-test,P<0.01).The media circulating fetal DNA was increased 3.9-fold in 30 pre-eclamptic women compared with 32 control pregnant women(LSD-test,P<0.01).Conclusion:1.Fetal DNA in maternal plasma can be detected as early as 48 days of gestation.2.The number of fetal DNA in maternal plasma increases with gestational age.3.Fetal DNA,we found an overall 3.9fold increase in women with pre-eclampsia compared with control pregnancies.4.Fetal DNA in maternal plasma is of great value in the non-invasive prenatal diagnosis.