Islet-resident macrophages (CD11b+Ly6C− or F4/80highCD11clow) predominate at steady-state and pro-inflammatory macrophages (CD11b+Ly6C+ or F4/80lowCD11chigh) accumulate during the course of obesity (32, 33). The gene discussed is ITGAM; the disease is obesity due to melanocortin 4 receptor deficiency.