The association of the placental MTHFR 3-UTR polymorphisms, promoter methylation, and MTHFR expression with preeclampsia

Preeclampsia (PE) is a pregnancy specific complication arises in presence of the placenta and disappears immediately after delivery. Therefore, the aim of the present study was to investigate the possible effects of the placental 3-UTR rs1537514C>G and rs4846049C>A polymorphisms and DNA methylation of the MTHFR gene on the MTHFR mRNA expression. The placenta of 74 PE pregnant women and 75 normotensive pregnant women were collected after delivery. The methylation status of the MTHFR promoter was assessed with Methylation Specific PCR (MSP). The rs1537514C>G and rs4846049C>A polymorphisms were genotyped using PCR-RFLP method. The mRNA expression levels were measured by Quantitative Real Time PCR. The results showed the lower MTHFR mRNA expression in the placenta of PE women. There was an association between hypermethylation and lower MTHFR mRNA expression in PE women and entire women but not normotensive pregnant women. The frequency of MTHFR rs1537514CG genotype was significantly lower in PE women; however, there was no association between MTHFR rs4846049C>A polymorphism and PE. The combination effects of MTHFR CG/AC genotypes and G-A haplotype of MTHFR rs1537514/rs4846049 polymorphisms were associated with lower risk of PE. The MTHFR rs1537514G (4869G) allele was associated with higher MTHFR mRNA expression in both groups. However, there was no relation between MTHFR rs4846049C>A polymorphism and MTHFR mRNA expression. Our findings showed lower MTHFR mRNA expression in PE women. The MTHFR rs1537514C>G polymorphism was associated with lower PE risk and MTHFR mRNA expression. Lower expression of MTHFR mRNA was observed in the women with the hypermethylated promoter.