To confirm the association of a functional single-nucleotide polymorphism (SNP), C1858T (rs2476601), in the PTPN22 gene of British Caucasian rheumatoid arthritis (RA) patients and to evaluate its influence on the RA phenotype.Methods
A total of 686 RA patients and 566 healthy volunteers, all of British Caucasian origin, were genotyped for C1858T polymorphism by PCR–restriction fragment length polymorphism assay. Data were analysed using SPSS software and the χ2 test as applicable.Results
The PTPN22 1858T risk allele was more prevalent in the RA patients (13.9%) compared with the healthy controls (10.3%) (P=0.008, odds ratio 1.4, 95% confidence interval 1.09–1.79). The association of the T allele was restricted to those with rheumatoid factor (RF)-positive disease (n=524, 76.4%) (P=0.004, odds ratio 1.5, 95% confidence interval 1.1–1.9). We found no association between PTPN22 and the presence of the HLA-DRB1 shared epitope or clinical characteristics.Conclusions
We confirmed the previously reported association of PTPN22 with RF-positive RA, which was independent from the HLA-DRB1 genotype.