In Africa and India, the frequencies of the disease and carriers are even higher de to protection against malaria that occurred for people with sickle cell trait discussed later in this paper. Beta globin is a major component of adult hemoglobin and its gene is located on chromosome 11 with more than 475 allelic variants (Ashley-Koch, Yang, and Olney, 2000)
In extreme cases, balancing selection can maintain alleles in populations long enough for speciation to occur. The mutation that produces sickle hemoglobin occurs spontaneously at a low rate (Fields, 2000)
The disease is caused by a change in a single amino acid difference in the beta chain of hemoglobin. (Malaria, sickle cell anemia, and balancing selection)
Mostly people from Africa or other coutries around the Mediterraean Sea get it. In the United States, African-Americans are most likely to have it (Howard, 1995)
" Having the trait rarely makes any problems, but makes it much less likely that the person can catch malaria, a blood disease spread by mosquitoes. Malaria is common in Africa, and those who had the sickle cell trait had good protection from this serious disease (Loupe, 199)
It is currently believed that around two and a half million African-Americans are carriers of the gene, many without being aware. This results in around one in every five hundred African-Americans developing sickle cell anemia (Chowning, 2000)
It is possible that the parents may need to be tested also in order to establish whether the homozygous or heterozygous condition was present (Weatherall, 1997). Prenatal diagnosis in the first trimester is now also possible for the disease, by analyzing fetal DNA obtained through chorionic villous biopsy; there is currently research towards diagnosis from cells taken from maternal circulation in order to minimize the risks to the fetus associated with fetal DNA collection (Frenette and Atweh, 2007)
Inherited diseases of hemoglobin are the most important, and these are termed hemoglobinopathies; it is into this category that sickle cell anemia falls. Sickle cell anemia has a genetic basis, and was the first genetic disease to be characterized at the molecular level (Ingram, 2004)
This occurs at position 6 on the ? chain, where glutamic acid is substituted by valine. Sickle cell anemia is a recessive disorder (Nagel, 2005), and so those with sickle cell anemia are homozygous for the mutation, producing mainly Hb S, with small amounts of Hb F
The exposure of sickle cells to acidic environments disrupts the internal environment of the cell, as it causes loss of potassium ions, resulting in dehydration of the cell. This may also alter the functions of the transport channels in the red blood cells, further reducing function (Steinberg, 2005)
The sickle cell mutation is one such disease which affects the ? chains. The sickle cell mutation results in a single amino acid substitution in the ? globin chain, which will result in the production of a different type of hemoglobin - Hb S (Weatherall, 1997)
This blockage is known to bring about what is commonly referred to as a sickle cell crisis episode. During a sickle cell crisis, severe pain brought about by the denial of oxygen to a certain body part is experienced (Falvo, 2005)
In order for this to occur, the fluid surrounding the amniotic sac is tested to watch out for the presences of hemoglobin S. This test is usually done when one or both parents of the unborn child have sickle cell anemia themselves (Bloom 1995)
Due to the fact that sickle cell anemia is hereditary, there are no methods of preventing attaining sickle cell anemia (Bloom 1995). There is also no absolute cure for this illness; there are only treatment methods (Harris 2001)
Research on sickle cell anemia and experimental treatments are being conducted in order to provide some relief for individuals with this illness (O'Malley 2006). The biggest research is being done on gene therapy (Pace 2007)
Pain-relieving medication is also used to take care of the pain associated with the painful episodes that occur in individuals with sickle cell anemia (Harris 2001). A more extreme measure can be undergoing blood transfusions which supply the body with a batch of new red blood cells to make up for the ones that have died and the ones that are damaged (Plasmar 2004)
A more extreme measure can be undergoing blood transfusions which supply the body with a batch of new red blood cells to make up for the ones that have died and the ones that are damaged (Plasmar 2004). Research on sickle cell anemia and experimental treatments are being conducted in order to provide some relief for individuals with this illness (O'Malley 2006)
Because of the shape of the red blood cells with sickle cell anemia, they become sticky and slow or block the flow of blood which ceases the amount of oxygen that can even go to the rest of the body (Bjorklund 2010). Getting diagnosed with sickle cell anemia can happen as young as right after birth, or even before a baby is born (Peterson 2009; Bloom 1995)
Red blood cells in individuals with sickle cell anemia will be rigid and moon-shaped, unlike normal red blood cells that are smooth and round. Because of the shape of the red blood cells with sickle cell anemia, they become sticky and slow or block the flow of blood which ceases the amount of oxygen that can even go to the rest of the body (Bjorklund 2010)
Anatomy and Physiology Sickle cell anemia is defined as being a severe form of the illness anemia, where not enough healthy red blood cells are present to carry the necessary oxygen to the rest of the body (Hwang & Shaparin 2003)