Hemojuvelin, also known as HFE2, is a membrane-bound and soluble protein which belongs to the repulsive guidance molecule (RGM) family. It is known that RGMs function through Neogenin, a homologue of the Netrin receptor deleted in colon cancer. In mammals, RGM family consists of three glycoproteins which have discrete expression patterns and functions (RGM-A, RGM-B, and RGM-C). Hemojuvelin is expressed in adult and fetal liver, heart, and skeletal muscle. Hemojuvelin acts as a bone morphogenetic protein (BMP) coreceptor. Enhancement of BMP signaling regulates hepcidin (HAMP) expression and iron metabolism. It plays a key role in iron metabolism. Hemojuvelin represents the cellular receptor for hepcidin. It may be a component of the signaling pathway which activates hepcidin or it may act as a modulator of hepcidin expression. Defects in hemojuvelin are the cause of hemochromatosis type 2A, also known as juvenile hemochromatosis (JH).