Iron overload is common in rural sub-Saharan African populations that have the custom of drinking a traditional fermented beverage with high
iron content. As with both excessive alcohol exposure and HFE
hemochromatosis, hepatic portal
fibrosis and micronodular
cirrhosis are prominent sequelae of
African iron overload. Two observations are therefore important in characterizing
iron overload in Africa. First, the hepatic
iron concentrations associated with
African iron overload often far exceed those seen in
alcoholic liver disease and histologic changes of alcohol effect are almost always absent. Second, the pattern of
iron accumulation in African
dietary iron is prominent in both macrophages and hepatic parenchymal cells; this pattern is in contrast to HFE homochromatosis, which is marked by predominantly parenchymal
iron-loading. For a long time, it was thought that
African iron overload was purely dietary in nature, that increased
iron and alcohol in the diet could fully explain markedly elevated tissue
iron levels sometimes seen with this condition. Recent studies of pedigrees suggest that, in addition to high
dietary iron content, a genetic defect may also be implicated in
iron overload in Africans. These studies indicate that the possible defect is different from mutations in the HFE gene frequently found in Caucasians with
iron overload, but the putative gene has not been identified. Recent studies also indicate that non-HFE
iron overload occurs in African-Americans, but the prevalence and possible genetic basis is yet to be determined.