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 some autoimmune diseases.