Several T2DM-associated genetic variants have been confirmed to be associated with GDM, such as TCF7L2 rs12255372 and MTNR1B rs10830963 [18] while the effects of other T2DM-associated genetic variants on GDM are controversial, such as WFS1 rs10010131 and ABCA1 rs1800977 [11,19]. This evidence concerns the gene MTNR1B and type 2 diabetes mellitus.