Fig. 1

Analysis of imprinted methylation at ubiquitous DMRs using HM450k methylation arrays. a The left side is a heatmap of absolute methylation (β values) for individual Infinium probes mapping to 35 DMRs in 67 placenta samples. Samples with abnormal methylation across a DMR are highlighted by yellow boxes. The right side of the figure reveals methylation difference according to severity, with blue and red representing hypo- and hypermethylation, respectively. Samples are classified by both the presence of pre-eclampsia (black yes; gray no) and fetal growth parameters (appropriate for gestational age light gray; SGA dark gray; IUGR black). *Adjacent to the DMR name indicates somatic establishment of methylation. b Pyrosequencing confirmation of the aberrant methylation profiles identified using HM450k arrays, as well as the quantification of additional placenta samples. The violin plots used include the median (white dot) and the interquartile range (black rectangle), with hypomethylated samples identified using the HM450k array platform highlighted as green data points, while hypermethylated samples are in red. The non-parametric Mann-Whitney-Wilcoxon test was used to calculate the statistical significance of the differences between IUGR and control groups (ns indicated no significance, p > 0.05). c Pyrosequencing quantification in cord blood samples. The violin plots show the distribution of methylation for 16 controls. Samples with aberrant placenta methylation profiles are highlighted. d Quantitative RT-PCR for transcripts regulated by affected DMRs. The violin plots represent the expression levels of 50 control placenta samples with normal birthweight and methylation. Samples with hypomethylation are highlighted as green data points, while hypermethylated samples are in red. e Allelic expression analysis was performed for the H19 transcript using the rs2839704 SNP, with allelic contributions quantified by pyrosequencing