This has already been shown for COPA, as described above, but is probably also the case in a few other monogenic forms of autoimmunity (e.g., APS1, IPEX, and CTLA4), in which relatively common autoimmunity-associated HLA alleles probably modify the risk of developing autoimmunity to specific autoantigens (59). The gene discussed is CTLA4; the disease is Autoimmunity.