MICROCYTIC ANEMIA MICE HAVE A MUTATION IN NRAMP2, A CANDIDATE IRON TRANSPORTER GENE

Although disorders of iron metabolism are prevalent, iron transport re mains poorly understood. To address this problem, we undertook a posit ional cloning strategy to identify the causative mutation in mice with microcytic anaemia (mk). Homozygous mk/mk mice have microcytic, hypoc hromic anaemia due to severe defects in intestinal iron absorption and erythroid iron utilization(1-4). We report the identification of a st rong candidate gene for mk, and suggest that the phenotype is a conseq uence of a missense mutation in Nramp2 (ref. 5), a previously identifi ed gene of unknown function. Nramp2 is homologous to Nramp1, a gene ac tive in host defense. If Nramp2 is mk, as the cumulative evidence sugg ests, our findings have broad implications for the understanding of ir on transport and resistance to intracellular pathogens.