In Section I, Dr. Beutler also discusses the types of hemochromatosis that exist as acquired and as hereditary forms. Acquired hemochromatosis occurs in patients with marrow failure, particularly when there is active ineffective erythropoietin. Hereditary hemochromatosis is most commonly due to mutations in the HLA-linked HFE gene, and hemochromatosis clinically indistinguishable from HFE hemochromatosis is the consequence of mutations in three transferring receptor-2 gene. A more severe, juvenile form of iron storage disease results from mutations of the gene encoding hepcidin or of a not-yet-identified gene on chromosome 1 q. Autosomal dominant iron storage disease is a consequence of ferroportin mutations, and a polymorphism in the ferroportin gene appears to be involved in the African iron overload syndrome.