BACKGROUND: In this study we report on the possible connection between single nucleotide polymorphisms (SNPs) in natural resistance-associated macrophage protein 1 (NRAMP1) gene and the risk of rheumatoid arthritis (RA) in the Chinese Han population.

MATERIAL AND METHODS: A total of 248 participants consisting of 116 RA cases and 132 healthy individuals were recruited for the current study. Genotyping for NRAMP1 gene polymorphisms was implemented using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The chi-square test was used to detect discrepancies in genotype and allele frequencies between the RA case group and the control group. Odds ratios (ORs) with 95% confidence intervals (CIs) was used to evaluate relative risk of RA. The results were adjusted by logistic regression analysis.

RESULTS: The TT genotype and T allele in rs17221959 showed dramatically different distribution between RA cases and healthy controls. After adjustment, TT genotype (OR=0.338, 95%CI=0.278–1.214, P=0.028) and T allele (OR=0.608, 95%CI=0.298–0.956, P=0.005) showed close association with reduced risk of RA. For rs1059823, no obvious diversity was uncovered in either genotype or allele distribution between the 2 groups. Interaction analysis showed that smoking decreased the protective function of TT in rs17221959.

CONCLUSIONS: This study suggested that the TT genotype and T allele in rs17221959 decreased RA risk. Smoking could decrease the protective effect of TT.

Keywords: Arthritis, Juvenile, Multidrug Resistance-Associated Proteins, Polymorphism, Genetic, Smoking, Alleles, Arthritis, Rheumatoid, Asians, Case-Control Studies, Cation Transport Proteins, ethnicity, Gene Frequency, Genetic Association Studies, Genetic Predisposition to Disease, Genotype, Odds Ratio, Polymorphism, Single Nucleotide, Risk Factors