A single nucleotide polymorphism of PTPN22, 1858C>T (rs2476601), disrupts an interaction motif in the protein, and is the most important non-HLA genetic risk factor for rheumatoid arthritis and the second most important for juvenile idiopathic arthritis.
No independent role of the -1123 G>C and+2740 A>G variants in the association of PTPN22 with type 1 diabetes and juvenile idiopathic arthritis in two Caucasian populations.
The discovery that a single-nucleotide polymorphism (SNP) in lymphoid tyrosine phosphatase (LYP), encoded by the PTPN22 gene, is associated with type 1 diabetes (T1D) has now been verified by numerous studies and has been expanded to rheumatoid arthritis, juvenile rheumatoid arthritis (JRA), systemic lupus erythematosus, Graves' disease, generalized vitiligo and other human autoimmune diseases.
Association between the PTPN22 gene and rheumatoid arthritis and juvenile idiopathic arthritis in a UK population: further support that PTPN22 is an autoimmunity gene.