The index SNP associated with endometriosis on chromosome 2p25.1 is a common splice variant in the oestrogen-responsive growth regulation by oestrogen in breast cancer 1 (GREB1) gene33, 37 and SNPs associated with endometriosis on chromosome 12q22 increase expression of the transmembrane adherens junctions protein coding gene vezatin (VEZT) in RNA from blood and endometrium38. Here, GREB1 is linked to endometriosis.