INS and type 2 diabetes mellitus: Large-scale GWASs have identified many susceptibility genes for GDM that overlap with those of T2DM, such as IGF2BP2, MTNR1B, TCF7L2, INSR, IRS1, HHEX, CDKAL1, GCK, and KCNQ1, most of which are associated with insulin secretion.