Sickle Cell Anemia

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Sickle Cell Anemia Sickle cell anemia is caused by a defect in the gene that controls the production of normal hemoglobin, which is an iron-containing protein in red blood cells that transports oxygen from the lungs to body tissues. The defective gene results in the production of abnormal hemoglobin known as hemoglobin S. If you have the disorder, you inherited one gene for hemoglobin S from each of your parents. The gene is recessive, so if you received a copy of the gene from just one parent, you are a carrier of the sickle cell gene. Under certain conditions, after hemoglobin S releases its oxygen, its molecules clump together forming rigid and elongated crystals. The crystals settle to one side of the cell, which collapses the other side. These red blood cells, which normally look like miniature inner tubes, become stiff and distorted in appearance. Some cells take on the shape of a crescent or farmer's sickle, while others may resemble teardrops or stars. These misshapen cells stick to each other, and because of a chemical on their surface, they also stick the vessel walls. In the capillaries, the sticky, rigid, odd-shaped cells create a logjam. This causes a block in blood flow and deprives body tissues of their necessary oxygen. Without oxygen, cells begin to die and tissues suffer damage. These episodes are painful for the patient, but they are not permanent. Sickled red cells eventually regain their normal round shape when they are re-oxygenated and re-hydrated. Sickling can be triggered whenever the rate of blood flow is reduced, or when the body's supply of water or oxygen decreased. Some causes of sickling are dehydration, cold temperatures, a change in available oxygen or air pressure, and fever or a viral inf... ... middle of paper ... ... carrier. Researchers also are working on replacing the gene that makes defective hemoglobin in sickle cell disease patients with one that makes normal hemoglobin. In a laboratory experiment using blood cells from people who carry the sickle cell gene, researchers were able to change sickled cells into normal cells using an enzyme called a ribozyme. The ribozyme cut out the mutated instructions in the cells' genetic pattern and replaced them with the correct instructions, according to a report in the June 5, 1998, issue of Science. Next, researchers plan to try the technique on animals. There is no cure for sickle cell anemia yet, but in the coming years there should be something that will prevent people from getting it. People with sickle cell can live a mainly normal life. Most people join various support groups and should be under medical treatment.

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