TPO encodes a primary autoantigen in both Hashimoto's Thyroiditis (HT) and Graves' Disease (GD); PTPRN2, and FLG encode primary autoantigens in Type-1 Diabetes (T1D) and Rheumatoid Arthritis (RA) respectively (Table 1). This evidence concerns the gene PTPRN2 and type 1 diabetes mellitus.