In our center, the analysis of RA patients and controls, all of Italic ancestry, showed a PTPN22 T1858 allele frequency of 5.7% in patients compared to 3.7% in controls (OR = 1.58; 95%CI = (1.01–2.49); p = 0.045) (Table 1). Here, PTPN22 is linked to rheumatoid arthritis.