HAMP and hemochromatosis type 2: Juvenile hemochromatosis is the name of the HH types 2a and 2b (OMIM #602390 and #613313) that are caused by mutations in the hemojuvelin (HJV) protein (coded by the HFE2 gene) and in the iron hormone hepcidin (coded by the HAMP gene) (OMIM *608374 and *606464) [2,15].