Inflammatory bowel disease and the genes for the natural resistance-associated macrophage protein-1 and the interferon-gamma receptor 1.

The genes for the interferon-gamma receptor 1 and the natural resistance-associated macrophage protein 1 (NRAMP1) control the immune response to intracellular microbial pathogens. Such pathogens, in particular Mycobacterium paratuberculosis, have been implicated in the pathogenesis of Crohn's disease. We studied markers in the genes for NRAMP1 and two mutations in the interferon-gamma receptor in relation to inflammatory bowel disease (IBD) in the following groups: 270 healthy individuals, 74 patients with Crohn's disease, 72 patients with ulcerative colitis, and 40 patients with primary sclerosing cholangitis. We studied the allele frequencies of two restriction fragment length polymorphisms in the gene for NRAMP1 and the prevalence of two mutations in the interferon-gamma receptor 1 gene. The markers in the NRAMP1 gene were not associated with inflammatory bowel disease. Also, the mutations in the interferon-gamma receptor 1 were not found in the 186 IBD patients. Genetic markers in NRAMP1 are thus not associated with IBD. Therefore this gene is not likely to play a role in the pathogenesis of IBD. The mutation in the interferon-gamma receptor was not found in our IBD patients group.