GNRH1 and systemic lupus erythematosus: The differences in SLE by gender may be attributed to differences in the metabolism of sex hormones and/or gonadotropin-releasing hormone (GnRH) signalling.21 This also led to the gender difference at age distribution of SLE patients: women had the highest incidence of SLE at the younger age groups while men had the highest incidence at the older age group.