Abstract
Endometriosis is a chronic, estrogen-driven inflammatory disorder affecting approximately 10% of reproductive-aged women globally. Despite increasing genomic insights into advanced-stage disease, the genetic underpinnings of early-stage endometriosis remain poorly understood, limiting opportunities for timely diagnosis and intervention. This study explores the contribution of regulatory variants, including those derived from ancient hominin introgression, and their interaction with modern environmental exposures in shaping endometriosis susceptibility. We conducted a dual-phase literature review to identify genes implicated in endometriosis pathophysiology and endocrine-disrupting chemical (EDC) sensitivity. Five genes (IL-6, CNR1, IDO1, TACR3, and KISS1R) were selected based on tissue expression, pathway involvement, and EDC reactivity. Whole-genome sequencing (WGS) data from the Genomics England 100,000 Genomes Project were analysed in nineteen females with clinically confirmed endometriosis. Variant enrichment, co-localisation, and linkage disequilibrium analyses were conducted, and functional impact was evaluated using public regulatory databases. Six regulatory variants were significantly enriched in the endometriosis cohort compared to matched controls and the general Genomics England population. Notably, co-localised IL-6 variants rs2069840 and rs34880821-located at a Neandertal-derived methylation site-demonstrated strong linkage disequilibrium and potential immune dysregulation. Variants in CNR1 and IDO1, some of Denisovan origin, also showed significant associations. Several of these variants overlapped EDC-responsive regulatory regions, suggesting gene-environment interactions may exacerbate risk. These findings propose a novel perspective of endometriosis susceptibility, in which ancient regulatory variants and contemporary environmental exposures converge to modulate immune and inflammatory responses. This integrative approach identified new potential biomarkers for early-stage detection of endometriosis.