Most risk variants for type 2 diabetes in healthy populations act through impairing insulin secretion (resulting in beta cell dysfunction) rather than insulin action (resulting in insulin resistance) which establishes that inherited abnormalities of beta cell function or mass (or both) are critical precursors in type 2 diabetes (Florez, 2008; McCarthy, 2010; Voight et al., 2010; Petrie et al., 2011). This evidence concerns the gene INS and type 2 diabetes mellitus.