For Stage A endometriosis, the top pathway enriched in the GWAS results was the ERK1 ERK2 MAPK pathway from the Signal Transduction (ST) database (P = 5.0 × 10−4, FDR-P = 5.0 × 10−4, Bonferroni-P = 0.011). Here, MAPK1 is linked to endometriosis.