We specifically chose GPR119, GPR84, GPR40, and TGR5 to use as a combined stimulus since these receptors were up-regulated in obesity and RYGB, and as GPR119 and GPR40 have been shown to exhibit synergistic effects on GLP-1 secretion [15]. The gene discussed is FFAR1; the disease is obesity due to melanocortin 4 receptor deficiency.