NRAMP1 is not associated with asthma, atopy, and serum immunoglobulin E levels in the French Canadian population

Reduced infection by mycobacteria, including Mycobacterium tuberculosis, may be partly responsible for increased prevalence of allergic and autoimmune diseases in developed countries. In a murine model of innate resistance to mycobacteria, the Nramp1 gene has been shown to affect asthma susceptibility. From this observation, it was proposed that human NRAMP1 may be a modulator of asthma risk in human populations. To experimentally test the candidacy of NRAMP1 in asthma susceptibility, we characterized five genetic variants of NRAMP1 (5' CA(n), 274C > T, 469 + 14G > C, D543N, and 1729+del4) in an asthma family-based cohort from northeastern Quebec. We did not observe any significant association between NRAMP1 variants (either allele or haplotype specific) with asthma, atopy, or serum immunoglobulin E levels. These results demonstrate that, in spite of direct involvement of Nramp1 in a murine asthma model, in human populations NRAMP1 is not likely to be a major contributor to the genetic etiology of asthma and asthma-related phenotypes.