With such beneficial properties, GLP-1 analogues are commonplace in the glycaemic control of patients with type 2 diabetes mellitus (T2DM) and presently four drugs within this class are licensed for use in T2DM: exenatide (Byetta) [10], liraglutide (Victoza) [11], lixisenatide (Lyxumia) [12], and prolonged-release exenatide (Bydureon) [13]. This evidence concerns the gene GCG and type 2 diabetes mellitus.