Iron overload[edit]
Main article: Iron overload
The body is able to substantially reduce the amount of iron it absorbs across the mucosa. It does not seem to be able to entirely shut down the iron transport process. Also, in situations where excess iron damages the intestinal lining itself (for instance, when children eat a large quantity of iron tablets produced for adult consumption), even more iron can enter the bloodstream and cause a potentially deadly syndrome of iron overload. Large amounts of free iron in the circulation will cause damage to critical cells in the liver, the heart and other metabolically active organs.
Iron toxicity results when the amount of circulating iron exceeds the amount of transferrin available to bind it, but the body is able to vigorously regulate its iron uptake. Thus, iron toxicity from ingestion is usually the result of extraordinary circumstances like iron tablet over-consumption [22][1] rather than variations in diet. The type of acute toxicity from iron ingestion causes severe mucosal damage in the gastrointestinal tract, among other problems.
Chronic iron toxicity is usually the result of more chronic iron overload syndromes associated with genetic diseases, repeated transfusions or other causes. In such cases the iron stores of an adult may reach 50 grams (10 times normal total body iron) or more. Classic examples of genetic iron overload includes hereditary hemochromatosis (HH) and the more severe disease juvenile hemochromatosis (JH) caused by mutations in either the gene RGMc gene, a member of a three gene repulsive guidance molecule family,[23] (also called hemojuvelin (HJV), and HFE2), Hemojuvelin, or the HAMP gene that encodes (an iron regulatory peptide). The exact mechanisms of most of the various forms of adult hemochromatosis, which make up most of the genetic iron overload disorders, remain unsolved. So while researchers have been able to identify genetic mutations causing several adult variants of hemochromatosis, they now must turn their attention to the normal function of these mutated