African iron overload (African iron overload) - SLC40A1 Gene
African iron overload is a process that involves excessive absorption of dietary iron. Excess iron accumulates in the tissues and organs of the body, particularly the liver, bone marrow and spleen. Iron concentrations in the body are primarily regulated by controlling the amount of iron absorbed from the diet.
African iron overload was observed for the first time in the central and southern rural populations in Africa among people who drink traditional beer brewed in uncoated steel drums, which allow the iron to pass the beer. However, not all individuals who drink beer develop iron overload African, and not all people of African descent to iron overload drink beer. Therefore, genetic differences that affect the risk of developing this condition were sought.
In African iron overload, excess iron accumulates primarily in reticuloendothelial cells. The reticuloendothelial cells include macrophages in the bone marrow and spleen and liver Kupffer cells. Later, iron also accumulates in hepatocytes. This pattern is different from that observed in a process similar iron overload called hereditary hemochromatosis, in which excess iron accumulates predominantly in hepatocytes.
When too much iron is absorbed, iron overload can eventually damage the tissues and organs. Iron overload in the liver may lead to cirrhosis, which increases the risk of developing hepatocellular carcinoma. Iron overload in immune cells can affect your ability to fight infections. In addition, African iron overload is associated with an increased risk of developing infections such as tuberculosis. Too much iron can also cause a breakdown of vitamin C in the body at a faster than normal pace, so that those affected are at increased risk of problems vitamin C deficiency such as scurvy. Other signs and symptoms may include mild anemia related, possibly because iron that accumulates in the liver, bone marrow and spleen is less available for the production of erythrocytes; and high levels of ferritin in the blood.
Some studies indicate that a variation in the SLC40A1 gene (solute carrier family 40 member 1), located on the long arm of chromosome 2 (2q32), increases the risk of developing increased iron stores in people of African descent. This variation is found in 5 to 20% of people of African descent, but usually not found in other populations. The SLC40A1 gene encodes ferroportin protein, involved in the process of absorption of iron in the body. The dietary iron is absorbed through the mucosa of the small intestine. Then ferroportin transports iron from the small intestine into the bloodstream to be carried by the blood to the tissues and organs of the body. Ferroportin also transports iron reticuloendothelial cells, found in liver, spleen and bone marrow. The amount of iron absorbed by the body depends on the amount of iron stored and released by intestinal and reticuloendothelial cells. The amount of ferroportin available for iron transport outside the cells is controlled by the iron regulatory protein, hepcidin. Hepcidin binds ferroportin and makes decomposes when the amounts of iron in the body are suitable. When the body lacks iron, hepcidin levels decrease so that more ferroportin available.
SLC40A1 gene variation some studies have associated with increased iron stores in people of African descent can affect the way in which ferroportin helps regulate iron absorption in the body. This effect appears to be more pronounced in males. Variation SLC40A1 gene associated with increased iron stores replaces the amino acid glutamine with histidine at amino acid position 248 in the sequence of protein ferroportin (Q248H or Gln248His). The Q248H variation may affect the way in which ferroportin helps regulate the concentrations of iron in the body, resulting in a greater risk of iron overload African.
Iron overload African appears to be hereditary, and a high content of iron in the diet appears to be the major contributor to the development of the disease. There may also be a genetic contribution, but the pattern of inheritance is unknown. People with a specific variation in the SLC40A1 gene can inherit an increased risk for the condition, but not the disease itself. Not all people with this disease have variation in the gene, not all people with varying develop the disease.
Tests in IVAMI: in IVAMI perform detection of mutations associated with African iron overload, by complete PCR amplification of exons SLC40A1 gene, and subsequent sequencing.
Samples recommended: EDTA blood collected for separation of blood leukocytes, or impregnated card blood sample desiccated (IVAMI can mail the card to deposit the blood sample).