What are the genetic changes related to African iron overload ?
African iron overload was first noted in rural central and southern African populations among people who drink a traditional beer brewed in uncoated steel drums that allow iron (a component of steel) to leach into the beer. However, not all individuals who drink the beer develop African iron overload, and not all individuals of African descent with iron overload drink the beer. Therefore, researchers are seeking genetic differences that affect the risk of developing this condition.  Some studies have indicated that a variation in the SLC40A1 gene increases the risk of developing increased iron stores in people of African descent. This variation is found in 5 to 20 percent of people of African descent but is not generally found in other populations.  The SLC40A1 gene provides instructions for making a protein called ferroportin. This protein is involved in the process of iron absorption in the body. Iron from the diet is absorbed through the walls of the small intestine. Ferroportin then transports iron from the small intestine into the bloodstream, and the iron is carried by the blood to the tissues and organs of the body. Ferroportin also transports iron out of reticuloendothelial cells in the liver, spleen, and bone marrow. The amount of iron absorbed by the body depends on the amount of iron stored and released from intestinal cells and macrophages.  The SLC40A1 gene variation that some studies have associated with increased iron stores in people of African descent may affect the way ferroportin helps to regulate iron absorption in the body. However, researchers suggest that this variation is not associated with most cases of African iron overload.