A et al. [42] proved that the decline of iron release by macrophages was the principal driving factor of anemia in NCOA4−/− animals, especially those manifesting iron deficiencies; however, whether this phenomenon is caused by an inherent defect of erythrocytes or iron retention due to ferritin degradation dysfunction caused by inactivation of NCOA4 remains to be further studied. The gene discussed is NCOA4; the disease is Iron deficiency anemia.