Considering that (i) both spleen and bone marrow macrophages of Irp2-/- mice display iron deficiency, (ii) both spleen and bone marrow are erythropoietic tissues, (iii) splenic macrophages play an essential role in recycling iron from senescent RBC, the iron deficiency of splenic macrophages probably results from reduced acquisition of iron from red cell turnover in anemic Irp2-/- mice. The gene discussed is IREB2; the disease is Iron deficiency anemia.