The +1858C/T PTPN22 gene polymorphism confers genetic susceptibility to rheumatoid arthritis in Mexican population from the Western Mexico.

Introduction: Rheumatoid arthritis (RA) is a common autoimmune disease with a complex genetic background. The PTPN22 gene encodes lymphoid tyrosine phosphatase LYP, a potent negative regulator of T cell activation. Polymorphic variants of this gene have previously been associated with various autoimmune disorders.