Hepcidin, also known as HAMP, HEPC, LEAP1 or HFE2B, is an 84 amino acid secreted protein that regulates iron-related signaling events. Highly expressed in liver with lower expression in heart, brain, lung, prostate and thyroid, hepcidin is thought to maintain iron homeostasis and, in conjunction with the HFE protein (a protein that is defective in hereditary hemochromatosis), may mediate both iron storage in macrophages and intestinal iron absorption. Additionally, hepcidin has strong antimicrobial activity against gram-positive and gram-negative bacteria, as well as certain yeast strains, suggesting that hepcidin may play a crucial role in staving off bacterial infections. Defects in the gene encoding hepcidin are the cause of hemochromatosis type 2B (also known as juvenile hemochromatosis), an early-onset autosomal recessive disorder that results in severe iron overload and is characterized by hepatic fibrosis, hypogonadotrophic hypogonadism and cardiomyopathy.