TCF7L2 and type 2 diabetes mellitus: FTO, and TCF7L2 have been deemed two of the most important T2D susceptibility genes to date (54–57, 109, 110), while additional SNPs in MCP-1, SLC30A8, GCK, PRKCZ, GIPR, IGFBP-7, PTPN1, PPARγ, KCNQ1, BCL11A, CALM2, CRY2, CAMK1D, THADA, ABCG1, SOCS3, SREBF1, TXNIP have either been associated with glycaemic traits, T2D or risk of T2D-linked complications (63, 64, 110–119).