NRAMP1 gene polymorphisms in patients with rheumatoid arthritis in Koreans

Natural resistance-associated macrophage protein 1 (NRAMP1) is a genetic locus associated with innate resistance or susceptibility of murine hosts to infection with intracellular pathogens such as Salmonella, Leishmania and Mycobacterium. The human homologue of the Nramp1 gene, designated NRAMP1, has been investigated as a candidate gene for genetic susceptibility to autoimmune diseases as well as infections. This study tries to determine whether NRAMP1 polymorphisms are associated with susceptibility to rheumatoid arthritis in Koreans. The nine NRAMP1 polymorphisms (1 microsatellite, 1 variation in 3' UTR, 5 silent substitution, 2 amino acid substitution) were typed by PCR-RFLP in 74 patients with rheumatoid arthritis (RA) and 53 healthy controls in Koreans. The distribution of allele and genotype frequencies were compared between patients and controls. Three NRAMP1 polymorphisms (823C/T, D543N and 1729+55del4) were significantly associated with RA. In addition, there were significant differences in the genotype frequencies for 823C/T, D543N and 1729+ 55del4 polymorphisms between RA patients and controls. Genotypes of A/A homozygote for D543N and TGTG deletion homozygote for 1729+55del4 were only detected in the patient group. These data indicate that genetic polymorphisms of NRAMP1 might be associated with the susceptibility to rheumatoid arthritis in Koreans.