Both HFE and TMPRSS6 are involved in iron homeostasis by regulating the production of hepcidin, which is considered to be the “master” iron regulator; mutations in HFE cause the most common form of hereditary hemochromatosis while mutations in TMPRSS6 cause iron-refractory iron deficiency anemia (IRIDA). The gene discussed is TMPRSS6; the disease is hereditary hemochromatosis.