The effect of PTPN2:rs478582 on PTPN2 gene expression in RA with heterozygous (TC) or minor (CC) allele was 8.67 ± 5.59 (N = 24) compared to 10.6 ± 7.47 (N = 23) in healthy controls with similar SNPs and lower than healthy controls without SNPs (TT) (9.49 ± 5.13; N = 8). Here, PTPN2 is linked to rheumatoid arthritis.