Since the ‘official’ discovery of Tregs in 1995 as a small CD4 + T-cell subpopulation with high levels of IL-2Rα (CD25) expression and the capacity of protecting thymectomized mice from autoimmunity [8], we learned a lot about the crucial role of Tregs in immune responses [9, 10]. The gene discussed is IL2RA; the disease is Autoimmunity.