In hereditary hemochromatosis (except for ferroportin disease), loss of any one of the hepcidin regulator genes (HFE, HAMP, HJV, and TFR2) attenuates or abrogates intracellular hepcidin signal transduction and hepcidin secretion [6, 9]. The gene discussed is HAMP; the disease is hemochromatosis type 4.