Based on these observations, we have chosen to confirm previous findings and evaluate additional genetic variants which have a reported effect on either insulin action (RETN -420C>G) [18] or insulin secretion (KCNJ11 E23K, HNF4A rs1884614 and rs2144908, HNF1A I27L, GCK -30G>A, and SLC30A8 R325W) [19-25] and which have previously been associated with T2D in large scale studies or meta-analysis [21,26-30]. This evidence concerns the gene GCK and type 2 diabetes mellitus.