title: Explore the dynamic alternation of gene PLAC4 mRNA expression levels in maternal plasma in second trimester for nonivasive detection of trisomy 21.
abstract: OBJECTIVE
  Noninvasive prenatal detection of trisomy 21 (T21) has been achieved by measuring the ratio of two alleles of a single nucleotide polymorphism in circulating placenta specific 4 (PLAC4) mRNA in maternal plasma with a few assays in recent years. Our research is to explore the variations of PLAC4 mRNA expression level in maternal plasma with normal pregnancies in second trimester, which can provide pregnant women deeper insights with suitable detection period for the non-invasive prenatal detection of T21.
  
  
  METHODS
  We measured a serial plasma PLAC4 mRNA concentrations weekly from the same 25 singleton normal pregnant women. We recruited maternal plasma samples from 45 singleton pregnant women, comprising of 25 euploid pregnancies (control group; range, 17 to 21 weeks) and 20 T21 pregnancies (T21 group; range, 19 to 24 weeks). With the application of reverse transcription polymerase chain reaction, we achieved an insight of PLAC4 mRNA expression levels in maternal plasma during second trimester with euploid pregnancies.
  
  
  RESULTS
  Among the control group, the levels of PLAC4 mRNA expression in the gestation of 17 to 18 weeks were significantly less than those in the gestation of 18 to 21 weeks (P<0.05). The average PLAC4 mRNA concentration of the normal pregnant women was not higher than that of the T21 group (P>0.05).
  
  
  CONCLUSIONS
  The PLAC4 mRNA showed a higher level of expression in the gestation of 18 to 21 weeks with an euploid pregnancy of pregnant women. We also found that there was no significant difference in plasma PLAC4 mRNA concentration between the normal and the T21 pregnancies in second trimester.
authors.affiliation: Department of Prenatal Diagnosis Center, Wuxi Maternal and Child Health Hospital Affiliated Nanjing Medical University, Wuxi, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Genetic Engineering, Fu Dan University, Shanghai, China.
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Sun
authors.affiliation: Department of Prenatal Diagnosis Center, Wuxi Maternal and Child Health Hospital Affiliated Nanjing Medical University, Wuxi, China.
authors.forename: Dao-Zhen
authors.initials: DZ
authors.lastname: Chen
authors.affiliation: Department of Prenatal Diagnosis Center, Wuxi Maternal and Child Health Hospital Affiliated Nanjing Medical University, Wuxi, China.
authors.forename: Mu-Dan
authors.initials: MD
authors.lastname: Lu
authors.affiliation: Department of Prenatal Diagnosis Center, Wuxi Maternal and Child Health Hospital Affiliated Nanjing Medical University, Wuxi, China.
authors.forename: Ye
authors.initials: Y
authors.lastname: Tang
authors.affiliation: Department of Prenatal Diagnosis Center, Wuxi Maternal and Child Health Hospital Affiliated Nanjing Medical University, Wuxi, China.
authors.forename: Jian-Pin
authors.initials: JP
authors.lastname: Xiao
keywords: Noninvasive prenatal detection; PLAC4; RNA concentration; Reverse transcription polymerase chain reaction; Trisomy 21