In particular, variants of T2D-associated genes, such as TCF7L2, KCNJ11, KCNQ1, CDKAL1, CDKN2A-CDKNA2B, FTO, HHEX, IGF2BP2, SLC30A8, MTNR1B, and PPARG, have been observed more frequently in women with GDM, as compared to women with normoglycemic pregnancies, in various populations [45,46,47,48,49,50,51,52,53]. This evidence concerns the gene MTNR1B and type 2 diabetes mellitus.