Association of PTPN22 rs2476601 Polymorphism with Rheumatoid Arthritis and Celiac Disease in Khuzestan Province, Southwestern Iran

BACKGROUND Single-nucleotide polymorphism (SNP) rs2476601 within protein tyrosine phosphatase non-receptor type 22 gene (PTPN22) has been shown to be a risk factor for different autoimmune diseases. This study explored the association of 1858 C/T SNP with rheumatoid arthritis (RA) and celiac disease (CD) in a region covering south-west of Iran. METHODS Totally, 52 patients with CD, 120 patients with RA, and 120 healthy subjects were selected. The samples were genotyped for the rs2476601 in PTPN22 gene using the tetra-amplification refractory mutation system polymerase chain reaction. RESULTS The frequency of +1858T risk allele was significantly increased in both RA (P=0.021, OR=2.56, 95%CI=1.19-5.47) and CD (P=0.002, OR=3.87, 95%CI=1.68-8.95) patients, as compared to the control group. However, no association was found between the +1858C/T PTPN22 gene SNP and the anti-cyclic citrullinated peptide and rheumatoid factor positivity in RA patients. CONCLUSIONS PTPN22 gene could play a crucial role in people's susceptibility to certain autoimmune diseases.