This study aims to identify genome-wide placental DNA differential methylation positions (DMPs) in fetal overgrowth and the associations with fetal growth factors, leptin and adiponectin. In the Shanghai Birth Cohort, we studied 30 pairs of placentals of large-for-gestational-age (LGA, birth weight>90th percentile, an indicator of fetal overgrowth) and optimal-for-gestational-age (OGA, 25th-75th percentiles, control) newborns matched by sex and gestational age. Placental DNA methylations were measured by the Illumina Infinium Human Methylation-EPIC BeadChip. Cord blood insulin, C-peptide, proinsulin, IGF-1, IGF-2, leptin and adiponectin concentrations were measured. We identified 543 DMPs (397 hypermethylated, 146 hypomethylated) comparing LGA vs. OGA at false discovery rate <5% and absolute methylation difference >0.05 adjusting for placental cell type heterogeneity, maternal age, pre-pregnancy BMI and HbA1c levels during pregnancy. We validated a hyper-methylated gene - cadherin 13 (CDH13) reported in a previous epigenome-wide association study, and validated a newly discovered differentially (hyper-)methylated gene -visual system homeobox 1 (VSX1) in an independent pyrosequencing study sample (47 LGA-control pairs). Pathway analysis did not detect any statistically significant pathway correcting for multiple tests. Adiponectin in cord blood was correlated with its gene methylation in the placenta, while other observed biomarkers were not. Fetal overgrowth was associated with a large number of altered placental gene DNA methylations. The study provides robust evidence suggesting that placental CDH13 and VSX1 genes are hyper-methylated in LGA. Placental gene methylation was correlated with cord blood biomarker for adiponectin, but not for leptin and fetal growth factors.
Overall design
Bisulphite converted DNA extracted from the placentas (fetal-side) of 30 LGA and 30 OGA pregnancies were hybridised to the Illumina Infinium HumanMethylation850 BeadChip
Less...
More...