During the past two decades, intensive investigation of the incretin hormone GLP-1 has led to the development of two categories of novel therapeutic agents for T2D: GLP-1 agonists and DPP-4 inhibitors (Lee and Jun, 2014; Holst and Madsbad, 2016; Tian and Jin, 2016). The gene discussed is GCG; the disease is type 2 diabetes mellitus.