Abstract：
Congenital heart disease (CHD) is a worldwide problem with high morbidity and mortality. Early diagnosis of congenital heart disease is still a challenge in clinical work. In recent years, few studies indicated that placental methylation may be predictors of CHD. More studies are needed to confirm the association between placental methylation and CHD. The aim of this study was to investigate the association between prenatal placental DNA methylation and CHD. Placental tissues were obtained from four fetuses during the second trimester with isolated, non-syndromic congenital heart disease, including three cases with double outlet right ventricle (DORV) and one case with tetralogy of Fallot (TOF), and four unaffected fetuses as controls. The Illumina Infinium Human Methylation 850K BeadChip assay was employed to identify differential methylation sites (DMSs) and differential methylation regions (DMRs). Differential methylation was evaluated by comparing the β-values for individual CpG loci in cases vs. controls. In addition, the function of genes was assessed through KEGG enrichment analysis, Gene Ontology (GO) analysis and KEGG pathway analysis. Compared with the control group, we identified 9625 differential methylation genes on 26,202 DMSs (p < 0.05), of which 6997 were hyper-methylation and 2628 were hypo-methylation. The top 30 terms of GO biological process and KEGG enrichment analysis of DMSs were connected with multiple important pathways of heart development and disease. Ten differentially methylated regions and the genes related to DMRs, such as TLL1, CRABP1, FDFT1, and PCK2, were identified. The deformity caused by the loss of function of these genes is remarkably consistent with the clinical phenotype of our cases. The DNA methylation level of placental tissue is closely associated with fetal congenital heart disease.
摘要：
先天性心脏病（CHD）是一个具有高发病率和高死亡率的世界性问题。先天性心脏病的早期诊断仍然是临床工作中的挑战。近年来,很少有研究表明胎盘甲基化可能是CHD的预测因子。需要更多的研究来证实胎盘甲基化与CHD之间的关联。本研究旨在探讨产前胎盘DNA甲基化与CHD的关系。胎盘组织在孕中期从四个胎儿中获得，非综合征性先天性心脏病,其中右心室双出口（DORV）3例，法洛四联症（TOF）1例，和四个未受影响的胎儿作为对照。IlluminaInfinium人甲基化850KBeadChip测定用于鉴定差异甲基化位点(DMS)和差异甲基化区(DMRs)。通过比较病例中单个CpG基因座的β值与差异来评估差异甲基化controls.此外,通过KEGG富集分析评估基因的功能，基因本体(GO)分析和KEGG通路分析。与对照组相比,我们在26,202个DMS上鉴定出9625个差异甲基化基因(p<0.05)，其中6997为超甲基化，2628为低甲基化。DMS的前30项GO生物过程和KEGG富集分析与心脏发育和疾病的多个重要途径有关。十个差异甲基化区域和与DMRs相关的基因，如TLL1、CRABP1、FDFT1和PCK2。由这些基因功能丧失引起的畸形与我们病例的临床表型非常一致。胎盘组织DNA甲基化水平与胎儿先天性心脏病密切相关。
