Quantification and application of the placental epigenetic signature of the RASSF1A gene in maternal plasma

Abstract

Objectives: The aims of the detection of hypermethylated RASSF1A gene in maternal plasma from all three trimesters of pregnancy were to show its feature of cell-free fetal DNA and to make up deficients of genetic markers. This study also aimed at investigating of its application value in pre-eclampsia compared with third trimester.

Methods: Eighty pregnant women (7-41 gestational weeks) including normal pregnant women (60 cases) and pre-eclamptic pregnant women (20 cases) were selected as study groups and 20 normal non-pregnant women were selected as control group. Free DNA of plasma samples was extracted, and RASSF1A levels before and after double-methylation-sensitive restriction enzyme digestion of HinP1I and HhaI were determined to measure total and fetal cell-free DNA, respectively. beta-Actin gene was detected as a control to confirm complete enzyme digestion.

Results: The median concentrations of hypermethylated RASSF1A gene were 46 copies/mL in first trimester, 96 copies/mL in second trimester, 527 copies/mL in third trimester and 1947 copies/mL in pre-eclampsia. There was positive correlation between fetal-derived hypermethylated RASSF1A levels and the severity of pre-eclampsia.

Conclusion: Hypermethylated RASSF1A gene may be considered as an epigenetic marker to detect the fetal DNA in maternal plasma and expands the clinical application of non-invasive prenatal diagnosis.