HLA-DRB1 and endometriosis: However,it is worth to mention that other class of MHC genes located near HLA-G (HLA-DQ and HLA-DRB1) have already been published in the context of endometriosis (Zong et al. 2002; Sundqvist et al. 2011; Sobalska-Kwapis et al. 2017).