Hemochromatosis Report

Hemochromatosis is a chronic alteration of iron metabolism which, if left untreated (or in advanced stages), can lead to serious organ damage (especially liver and pancreas). There are different types, all determined by mutations in specific genes involved at various levels in iron homeostasis. The most common type of hemochromatosis (HH - Hereditary Hemochromatosis or type 1) is related to the HFE gene and is transmitted in an autosomal recessive manner.
The mutation alters the sensitivity of a specific protein to dietary iron, causing excessive intestinal absorption.
The second type of hemochromatosis (juvenile) differs in the 2A and 2B forms, respectively linked to mutations in the HJV genes (which codes for hemojuvelin, involved in iron absorption but with roles not yet fully known) and HAMP (hepcidin, a protein that regulates iron levels as needed). Also transmitted in an autosomal recessive manner, this form is quite rare and occurs in adolescence. On the other hand, type 3 hemochromatosis is associated with mutations in the transferrin receptor (TFR2), which regulates the saturation level of an iron-binding protein called transferrin.
Type 4 is related to autosomal dominant mutations in the SLC40A1 gene, encoding ferroportin (responsible for transporting iron out of cells).
Finally, type 5 hemochromatosis is caused by the FTH1 gene which codes for a subunit of ferritin (the intracellular iron storage protein).
Other genes implicated in various pathways of iron metabolism are still being studied and their role as contributors to the onset of hemochromatosis is gaining increasing acceptance.