Department of Molecular Biology and Cell Pathology, Third Faculty of Medicine, Charles University, Ruska 87, 100 00 Prague, Czech Republic.
Exp Mol Pathol. 2010 Dec;89(3):241-7. doi: 10.1016/j.yexmp.2010.09.002. Epub 2010 Sep 22.
We determined the feasibility of universal fetal marker detection in maternal circulation. Using real-time PCR, we compared the levels of fetal (SRY and hypermethylated RASSF1A) and total (GLO gene and total RASSF1A) extracellular DNA and fractions of extracellular fetal DNA (SRY/GLO vs. hypermethylated RASSF1A/total RASSF1A) in maternal circulation. Sensitivity and specificity reached 100% as the fetal-specific hypermethylated RASSF1A sequence was detected in all 151 examined plasma samples derived from 70 normal pregnancies with a singleton male (n=51) or female (n=19) fetus sampled throughout gestation and absent in non-pregnant individuals (n=29). A strong positive correlation was observed between fetal-derived hypermethylated RASSF1A and SRY (ρ=0.66, P<0.001), total RASSF1A and GLO (ρ=0.65,P<0.001), SRY/GLO vs. hypermethylated RASSF1A/total RASSF1A ratio (ρ=0.62, P<0.001) in maternal plasma. The results indicate that a universal fetal marker could be useful not only for the confirmation of the presence of fetal cell-free DNA in maternal plasma but could enable quantification of cell-free fetal DNA in pregnancy associated disorders, independently of the sex of the fetus.
我们确定了在母体循环中进行普遍胎儿标志物检测的可行性。使用实时 PCR，我们比较了母体循环中外周胎儿（SRY 和高甲基化 RASSF1A）和总（GLO 基因和总 RASSF1A）游离 DNA 以及游离胎儿 DNA 分数（SRY/GLO 与高甲基化 RASSF1A/总 RASSF1A）的水平。当在整个妊娠期间采样的 70 例正常妊娠（单胎男性（n=51）或女性（n=19）胎儿）的所有 151 个血浆样本中检测到胎儿特异性高甲基化 RASSF1A 序列时，敏感性和特异性均达到 100%，而在非妊娠个体（n=29）中未检测到。在母体血浆中观察到胎儿衍生的高甲基化 RASSF1A 与 SRY（ρ=0.66，P<0.001）、总 RASSF1A 与 GLO（ρ=0.65，P<0.001）、SRY/GLO 与高甲基化 RASSF1A/总 RASSF1A 比值（ρ=0.62，P<0.001）之间存在强烈的正相关。这些结果表明，普遍的胎儿标志物不仅可用于确认母体血浆中游离胎儿 DNA 的存在，而且可以在妊娠相关疾病中独立于胎儿性别对游离胎儿 DNA 进行定量。
