The interleukin-2 receptor-α (IL-2RA) encodes the α-chain of the IL-2 receptor (IL-2R) complex (also known as CD25), which is central to immune regulation as an important modulator of self-tolerance and immunity [79], and the IL-2RA association with type 1 diabetes was originally identified by Vella and coworkers [80]. The gene discussed is IL2RA; the disease is type 1 diabetes mellitus.