title: Quantification and application of the placental epigenetic signature of the RASSF1A gene in maternal plasma.
abstract: OBJECTIVE
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Institute of Immunology, Medical College of Shanxi Datong University, Datong, China. dtyzfx@163.com
authors.forename: Fuxi
authors.initials: F
authors.lastname: Zhao
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Runhua
authors.initials: R
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Ke
authors.initials: K
authors.lastname: Cui
authors.forename: Yongming
authors.initials: Y
authors.lastname: Wu
authors.forename: Juncheng
authors.initials: J
authors.lastname: Guo
authors.forename: Yaqin
authors.initials: Y
authors.lastname: Mu
authors.forename: Xiying
authors.initials: X
authors.lastname: Wang
mesh_terms: D004247:DNA / Q000235:genetics / Q000378:metabolism; D019175:DNA Methylation / Q000235:genetics; D015252:Deoxyribonucleases, Type II Site-Specific / Q000378:metabolism; D044127:Epigenesis, Genetic / Q000235:genetics*; D005260:Female; D005865:Gestational Age; D006801:Humans; D016133:Polymerase Chain Reaction; D011225:Pre-Eclampsia / Q000097:blood / Q000235:genetics*; D011247:Pregnancy; D011296:Prenatal Diagnosis / Q000379:methods*; D013223:Statistics as Topic; D025521:Tumor Suppressor Proteins / Q000097:blood / Q000235:genetics*
chemical_list: C411762:RASSF1 protein, human; D025521:Tumor Suppressor Proteins; D004247:DNA; D015252:Deoxyribonucleases, Type II Site-Specific; C037130:GCGC-specific type II deoxyribonucleases