Evaluation of H19, Mest, Meg3, and Peg3 genes affecting growth and metabolism in umbilical cord blood cells of infants born to mothers with gestational diabetes and healthy mothers in Rafsanjan City, Iran

Abstract Hyperglycemia during the first trimester leads to an increased risk of innate malformations as well as death at times close to delivery dates. The methylated genes include those from paternal H19 and PEG3 and those from maternal MEST and MEG3 that are necessary for the growth and regulation of the human fetus and its placenta. The aim of this study was to evaluate and compare the expression of these genes in the cord blood of healthy infants born to mothers with gestational diabetes mellitus (GDM) and healthy mothers. This case-control study was conducted on the cord blood of 40 infants born to mothers with GDM and 35 infants born to healthy mothers. Mothers were identified by measuring oral glucose tolerance in the 24th–26th week of pregnancy. Cord blood was obtained post-delivery, and cord blood mononuclear cells were immediately extracted, using Ficoll solution. Then, RNA extraction and cDNA synthesis were performed, and gene expression of MEG3, PEG3, H19, and MEST was assessed through quantitative real-time PCR. Findings show that the expression levels of MEG3, PEG3, H19, and MEST genes were significantly decreased in mononuclear cord blood cells of infants born to mothers with GDM when compared to those of the healthy control group. These findings reveal that the reduction of imprinted genes in mothers with GDM is most likely due to changes in their methylation by an epigenetic process. Considering the importance of GDM due to its high prevalence and its side effects both for mother and fetus, recognizing their exact mechanisms is of high importance. This has to be studied more widely.