HAMP and hereditary hemochromatosis: Loss-of-function mutations in positive regulators of hepcidin or the hepcidin gene itself (Table 2) cause hereditary hemochromatosis [61], a set of diseases characterized by increased absorption of dietary iron, often causing massively increased body iron content, and high plasma iron concentrations that saturate the iron-binding capacity of transferrin, leading to the appearance of non-transferrin-bound iron (NTBI).