Other factors such as oxidoreductases [e.g., Duodenal Cytochrome b (Dytb), Ceruloplasmin (Cp), Hephaestin (Heph), and STEAP3) and modulatory proteins (e.g., Hemochromatosis (HFE), Hemojuvelin (HJV), Iron Regulatory Protein (IRP) 1/2, and Transmembrane Serine Protease 6 (TMPRSS6)] also play an active role in iron metabolism (Muckenthaler and Lill, 2012; Srai and Sharp, 2012). Here, HEPH is linked to hemochromatosis.