Belgrade rats exhibit microcytic, hypochromic anemia and systemic iron deficiency due to a glycine-to-arginine mutation at residue 185 in a metal ion transporter of a divalent metal transporter/divalent cation transporter/solute carrier 11 group A member 2 or 3 (DMT1/DCT1/SLC11A2), a member of the natural-resistance-associated macrophage protein (Nramp) family.