GCK and type 2 diabetes mellitus: There is some evidence from the study of common genetic variants related to type 2 diabetes (TCF7L, GCK, I/III polymorphisms of INS-VNTR and IGF-1) and its effects on birth weight, lending support to the notion that more moderate impairment of insulin secretion provides a link between inheritance of type 2 diabetes susceptibility and reduced weight at birth [11]–[14].