The theory that such alteration may contribute to disease pathogenesis is supported by the observation that many of the type 1 diabetes susceptibility loci identified by genome-wide association studies may well influence Treg function (e.g. IL2RA, IL2, PTPN2, CTLA4 and IL10) [12], a theme that is discussed in more detail below. The gene discussed is IL2; the disease is type 1 diabetes mellitus.