Insulin secretion is influenced by underlying genes affecting beta cell function (which constitute the largest group of genes implicated in T2DM pathogenesis in large-scale evaluations [18]) but can be suppressed further by elevations in lipids [36,37] and glucose itself [38], as well as dysfunction of other hormones including the incretin GLP-1 [17]. Here, GCG is linked to type 2 diabetes mellitus.