For example, a person carrying HLA-DR3 and CTLA-4 variants might develop Hashimoto's thyroiditis and type 1 diabetes, whereas another with HLA-DR3 plus additional variants in AIRE or FEZF2 genes could develop Hashimoto's thyroiditis and autoimmune gastritis, since AIRE mutations predispose to a broad spectrum of autoimmunity as seen in APS type I (Peterson and Peltonen, 2005[77], Lee et al., 2023[55]). The gene discussed is AIRE; the disease is type 1 diabetes mellitus.