[Genetic iron overloads and hepatic insulin-resistance iron overload syndrome: an update].
Hepcidin inhibits intestinal absorption of iron through internalisation of ferroportin. Its discovery helps to better understand the genetic iron overloads. The insulin resistance-hepatic iron overload (IR-HIO)--also coined as the dysmetabolic iron overload syndrome--is a common cause or iron overload. This article is a review about genetic iron overloads and IR-HIO. Type 1 haemochromatosis C282Y +/+ accounts for 95% of the haemochromatosis. Hepatic fibrosis may develop if serum ferritin is higher than 1000 microg/l but can be partially reversible with phlebotomies. Juvenile haemochromatosis (type 2) and type 3 haemochromatosis (mutation of the transferrin receptor 2) are very uncommon. Several mutations of the ferroportin gene can cause usually mild iron overload of autosomal dominant inheritance. Aceruleoplasminemia is an uncommon disorder involving cerebral iron overload. The causes and consequences of the IR-HIO are unknown. Treatment of IR-HIO is focused on metabolic syndrome and phlebotomies are questionable because the overload is moderate and intestinal absorption of iron seems to be low. MRI (or other non invasive methods) is needed to truly assess iron overload because serum ferritin overestimates it in metabolic syndrome. Several points have to be elucidated: how HFE interferes with hepcidin in type 1 haemochromatosis; the causes of variability of iron overload; the benefits of populations screening; the advantage of phlebotomies in IR-HIO; the use of new oral iron chelators.
Ruivard
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Service de médecine interne, Hôtel-Dieu, CHU de Clermont-Ferrand, boulevard Léon-Malfreyt, 63058 Clermont-Ferrand cedex 1, France. mruivard@chu-clermontferrand.fr
D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000502:physiology; D027682:Cation Transport Proteins / Q000235:genetics / Q000378:metabolism; D002614:Chelating Agents / Q000627:therapeutic use; D015331:Cohort Studies; D004195:Disease Models, Animal; D015444:Exercise; D005260:Female; D005293:Ferritins / Q000097:blood; D005799:Genes, Dominant; D006432:Hemochromatosis / Q000145:classification / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D064451:Hepcidins; D006720:Homozygote; D006801:Humans; D007333:Insulin Resistance; D007408:Intestinal Absorption; D007501:Iron / Q000378:metabolism; D019190:Iron Overload / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D008099:Liver / Q000378:metabolism*; D008103:Liver Cirrhosis / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D015201:Meta-Analysis as Topic; D024821:Metabolic Syndrome / Q000378:metabolism / Q000628:therapy; D009154:Mutation; D018962:Phlebotomy; D011446:Prospective Studies; D016032:Randomized Controlled Trials as Topic; D051381:Rats; D011990:Receptors, Transferrin / Q000235:genetics; D012307:Risk Factors; D000098742:Ferroportin
D023181:Antimicrobial Cationic Peptides; D027682:Cation Transport Proteins; D002614:Chelating Agents; C578702:HAMP protein, human; C578703:Hamp protein, rat; D064451:Hepcidins; D011990:Receptors, Transferrin; D000098742:Ferroportin; D005293:Ferritins; D007501:Iron