Global Endometrial DNA Multi-omics Analysis Reveals Insights into mQTL Regulation and Associated Endometriosis Disease Risk and Endometrial Function

Endometriosis is a leading cause of pain and infertility affecting millions of women globally. Biological and genetic effects on DNA methylation (DNAm) can influence gene regulation and contribute to complex disease. Herein, we characterize variation in endometrial DNAm and its association with menstrual cycle phase, endometriosis, and genetic variants through analysis of genome-wide genotype data and methylation at 759,345 DNAm sites in endometrial samples from 984 deeply-phenotyped participants. We estimate that 15.4% of the variation in endometriosis is captured by DNAm and identify significant differences in DNAm profiles and DNAm networks, associated with endometriosis, endometriosis sub-phenotypes and menstrual cycle phase, including opening of the window for embryo implantation. DNAm quantitative trait locus (mQTL) analysis identified 118,185 independent cis-mQTLs including 51 associated with risk of endometriosis highlighting candidate genes contributing to disease risk. Our work provides functional evidence for epigenetic targets contributing to endometriosis risk and pathogenesis. Data generated serve as a valuable resource for understanding tissue-specific effects of methylation on endometrial biology in health and disease. Bisulphite converted DNA from the 984 endometrial samples were hybridised to the Illumina Infinium MethylationEPIC Beadchip