Association analysis of the 1858C>T polymorphism in the PTPN22 gene in juvenile idiopathic arthritis and other autoimmune diseases

A functional single nucleotide polymorphism, 1858C4T, in the PTPN22 gene, encoding a tyrosine phosphatase, has been reported to be associated with type I diabetes and some other autoimmune diseases. To further investigate whether this polymorphism may be a general susceptibility factor for autoimmunity, we performed an association study in five different autoimmune diseases, three previously not tested. We found an association with juvenile idiopathic arthritis ( OR = 1.41; P = 0.04), not previously reported, and a tendency for an association with coeliac disease ( OR = 1.35; P = 0.08). In primary sclerosing cholangitis, no association was observed ( OR = 0.95; P = 0.8). Furthermore, we confirmed the increased risk in rheumatoid arthritis ( OR = 1.58; P = 0.001), but could not find support for an association with systemic lupus erythematosus ( OR = 0.94; P = 0.8). Altogether, we have provided further evidence of an association between autoimmune diseases and the 1858C4T polymorphism in PTPN22.