GCG and type 2 diabetes mellitus: It contained genes already known to be involved in GLP-1 stimulated insulin secretion (WFS1 [5], RYR2 [15], RAP1A [16]), glucose stimulated insulin secretion (VAV2 [17]), mediating the effects of GLP-1 on beta-cell mass (FOXO1 [18]) and genes implicated in type 2 diabetes through GWAS of Han Chinese [19] and Mexican [20] populations (PTPRD), a gene expression-based genome-wide association study [21] (CD44) and a linkage study in an African American population [22], (MAGI2 and CTNNA2).