SLC30A8 and type 2 diabetes mellitus: The three exome-wide significant gene-level signals explain an estimated 0.11% (MC4R), 0.092% (PAM) and 0.072% (SLC30A8) of T2D genetic variance, only 10–20% of the variance explained by the three strongest independent common-variant associations in the imputed GWAS (TCF7L2, 0.89%; KCNQ1, 0.81%; CDC123, 0.35%; Fig. 3b).