Genetic polymorphisms of the DNA repair gene UNG are associated with the susceptibility of rheumatoid arthritis

The involvement of uracil-DNA glycosylase (UNG) in the pathogenesis of cancer is well documented. In contrast, the role of this protein in rheumatoid arthritis (RA) development is not well defined, although previous studies suggest a possible link between autoimmune diseases and malignancy. Therefore, we aimed to examine whether there is a link between UNG genetic polymorphisms and RA. Our present study investigated the effects of UNG (rs3219218 and rs246079) single nucleotide polymorphisms (SNPs) on RA among Taiwan's Han Chinese population. Polymorphism of the UNG gene was analyzed in 192 controls and 183 RA patients. Genotyping for UNG SNPs was performed by restriction fragment length polymorphism assay. Our data confirmed statistically significant variations in genotype frequency distributions at rs246079 SNP between RA patients and controls (P = 3.05 × 10(-4)). The G allele at rs246079 SNP is a high-risk factor in developing RA (odds ratio [OR] = 1.77; 95% confidence interval [CI] = 1.290-2.42). A comparison of haplotype frequencies between the case and the control revealed that RA patients with the Ht2 haplotype are at additional risk for RA development (P = 0.042). Our data yielded new information on UNG polymorphisms associated with RA development and as RA molecular markers. The polymorphisms revealed by the present study merit further investigation.