Our first ever GWAS analysis for Stage A endometriosis (n = 1686 cases) revealed a novel locus, rs144240142 (P = 6.45 × 10−8, OR 1.71, 95%CI 1.23–2.37), an intronic SNP with MAF of 0.01, imputation info score >0.8, within the MAP3K4 gene (Table I, Fig. 1). The gene discussed is MAP3K4; the disease is endometriosis.