Incretin hormones are a group of intestinal metabolic peptides such as GLP-1 and GIP (gastric inhibitory peptide), which reduce hyperglycemia via several pathways, including inhibition of glucagon, stimulating insulin secretion, delaying the gastric emptying, appetite suppression, declining intestinal nutrients absorption, improvement of lipid metabolism, and promoting pancreatic β-cell efficiency [19, 21–24]. The gene discussed is GCG; the disease is Hyperglycemia.