Hypermethylated CpG sites in the MTR gene promoter in preterm placenta

Altered maternal one-carbon metabolism influences placental DNA methylation patterns and 'programs' the fetus for noncommunicable diseases in adult life.

Levels of plasma folate, vitamin B₁₂, homocysteine, mRNA and protein levels of MTHFR and MTR enzymes in placenta were compared among women delivering preterm (n = 83) and term (n = 75). MTR promoter CpG methylation was undertaken.

MTHFR and MTR mRNA levels were higher while protein levels were lower, and MTR CpG sites were hypermethylated in the preterm group, as compared with the term group. Methylated CpG sites were negatively associated with maternal plasma vitamin B₁₂ levels.

Study suggests a dysregulation of enzyme genes in remethylation arm of the one-carbon metabolism in placenta of women delivering preterm.