Hepcidin deficiency is a result of autosomal recessive mutations in the hepcidin gene or genes encoding hepcidin regulators, the hemochromatosis gene (HFE, most commonly mutated in hereditary hemochromatosis in Caucasians populations), transferrin receptor 2 (TfR2), or hemojuvelin [8]. The gene discussed is HAMP; the disease is hemochromatosis type 1.