No significant differences were found between the PTPN22 and CSK mRNA expression of patients with RA and other clinical characteristics, including disease duration, rheumatoid factor, anti-cyclic citrullinated peptide antibodies status, erosions, extra-articular manifestations, and CRP levels and erythrocyte sedimentation rate at RA onset. This evidence concerns the gene PTPN22 and rheumatoid arthritis.