Hemochromatosis type 2 (juvenile) is the early-onset and most severe form of rare hereditary hemochromatosis (HH), a group of diseases characterized by excessive tissue iron deposition of genetic origin. The disease is hemochromatosis type 2 (MONDO_0019257). Also known as: HFE2, JHH, Juvenile Hemochromatosis, juvenile hemochromatosis.