This SNP has also been associated with increased risk for multiple autoimmune diseases including rheumatoid arthritis (RA) (28), systemic lupus erythematosus (SLE) (53), Graves’ disease (52, 54), myasthenia gravis (55), primary Sjogren’s syndrome (56), generalized vitiligo (57), Addison’s disease (58), and alopecia areata (59) strongly suggesting PTPN22 regulates immunity. Here, PTPN22 is linked to rheumatoid arthritis.