Glucagon-like peptide 1 (GLP1) is a hormone secreted by the gut after a meal, and GLP1 agonists are now widely used as a treatment for type 2 diabetes mellitus, following the 2005 FDA approval of the first in class, exenatide, a 39 amino acid synthetic form of exendin-4, a GLP1-mimetic peptide that binds the GLP1 receptor (Maselli and Camilleri, 2021). The gene discussed is GCG; the disease is diabetes mellitus.