The importance of Bmp6 and hemojuvelin in hepcidin expression is evident from the fact that disruption of mouse Bmp6[6], [7] or Hfe2[11], [12] genes results in severe hemochromatosis, which is in terms of tissue iron overload similar to hemochromatosis caused by disruption of the hepcidin gene itself. The gene discussed is HAMP; the disease is hemochromatosis.