A systematic review and meta-analysis in women with moderate and severe endometriosis undergoing IVF with either the short or long GnRH agonist protocol showed higher clinical pregnancy rates in women who received the long GnRH agonist protocol; however, in their subgroup analysis of 14 non-randomized controlled trial studies of GnRH agonist downregulation protocols by duration (short, long and ultralong), there was no significant difference in reproductive outcomes [60]. The gene discussed is GNRH1; the disease is endometriosis.