GCK and diabetes mellitus: The genes fall into three main groups; known MODY (maturity-onset diabetes of the young) genes (GCK, HNF1A and PDX1)14, known genes reported in previous exome-wide analyses of glucose levels or T2D (G6PC2 and PAM)5,15, and novel genes not previously implicated by genetics in diabetes (GIGYF1, TNRC6B and PFAS).