A PTPN22 promoter polymorphism −1123G>C is associated with RA pathogenesis in Chinese

The minor allele of the non-synonymous single nucleotide polymorphism (SNP) +1858C>T within the PTPN22 gene has now been unequivocally confirmed as conferring susceptibility to RA in population from Europe and America, but not in population from Asia. The aim of this study was to jointly address and integrate these separate findings to further elucidate the association between the PTPN22 gene and RA in Chinese Hans of Guangdong province. Four hundred and ninety-four cases with RA and 496 healthy controls were randomly selected, their SNPs at position −1123G>C (rs2488457), +1858C>T (rs2476601), +788G>A (rs33996649), and rs1310182 were genotyped using PCR–RFLP, followed by agarose gel electrophoresis. +1858C>T (rs2476601) and +788G>A (rs33996649) are not polymorphic in Chinese Hans. Meanwhile, our result reveals that the degree of association between the promoter polymorphism, −1123G>C and RA, was analogous to that observed in Japanese reports (odds ratio [OR] = 1.517, 95% CI = [1.154–1.995], P = 0.003). Expression study also indicated a tendency for association between −1123G>C and PTPN22 gene expression. Our study underpins that the promoter polymorphism, −1123G/C, may be a causal SNP for RA in Asian.