Insulin secretion appears to be more heritable than insulin resistance: in genome-wide association studies (GWASs), only a few loci point to insulin resistance as the primary cause of type 2 diabetes, whereas the majority of the loci identified by GWAS point towards defects in pancreatic beta-cells, specifically impacting insulin secretion [10,11,12]. This evidence concerns the gene INS and type 2 diabetes mellitus.