PTPRN2 and rheumatoid arthritis: Long STRs within 20 genes have been associated with 16 common autoimmune diseases; these genes include the following: thyroid peroxidase (TPO), which encodes a primary autoantigen in Hashimoto’s thyroiditis (HT) and Grave’s disease (GD); filaggrin (FLG), which encodes a primary autoantigen in RA; and protein-tyrosine phosphatase, receptor-type, n, polypeptide 2 (PTPRN2), which encodes a primary autoantigen in type-1 diabetes (T1D) (see Table 7 of reference [76]).