Sickle cell anemia is caused by mutation of the HBB gene. Hemoglobin has two protein subunits known as beta-globin and two subunits called alpha-globin. HBB gene codes the instructions that are necessary for the manufacture of beta-globin. If HBB gene undergoes mutation, then it is likely that it will produce hemoglobin S, which is an abnormal version of beta-globin (News Medical, 2012). Moreover, mutations of HBB gene can result in the manufacture of an abnormal beta-globin known as hemoglobin C or hemoglobin E. Researchers have also established that low levels of beta-globin caused by mutations can lead to the development of an abnormality known as beta thalassemia. In case of sickle cell anemia occurrence, the both beta-globin subunits are replaced by hemoglobin S. Moreover, the second subunit of beta-globin is replaced by abnormal variant, such as hemoglobin C. This makes the shape of the red blood cells be distorted into a sickle shape. Due to this, the elasticity of the red blood cells is reduced.
It is necessary for blood cells to be elastic to ensure that they perform their functions well. Elastic red blood cells are able to deform and pass through the walls of capillaries, thus ensuring efficient transportation of oxygen. However, sickle shaped cells have low oxygen tension, which damages their cell membrane thus decreasing their overall elasticity. These cells fail to return to their normal shapes even if the oxygen tension is restored to its normal levels (News Medical, 2012). Since sickle cells are unable to deform as they pass through narrow capillaries, vessel ischemia and occlusion occurs. Thus, scientists argue that sickle cell anemia is caused by hemolysis of red blood cells in the spleen, since they are misshaped. Notably, sickle cells only live for 10-20 days while normal cells live for 90-120 days.
People who have the roots of their origin in Africa, India and Mediterranean, are at a greater risk of inheriting sickle cell trait compared to the other people. In addition, people who originate from Middle East, Caribbean, South and Central America are also at a greater risk of inheriting this trait compared to other people. In America, most patients suffering from sickle cell anemia are those who have inherited a sickle cell gene known as hemoglobin S. Sickle cell traits are passed through autosomal recessives. This genetic condition occurs when an individual receives two copies of an autosomal gene from each parent. If a person inherits two sickle cell genes from both parents, he or she will certainly have sickle cell disease (Genetics Home Reference, 2012). However, if a person inherits only one gene, he or she is likely to develop sickle cell trait. Sickle cell trait patients are only carriers and thus they can pass these genes to their children. If both parents have sickle cell trait, there is a 50 percent chance that their child will inherit sickle cell trait. If only one of the parents has sickle cell trait and the other parent has normal genes, there is a 25 percent chance that the child will inherit sickle cell trait. If one of the parents has sickle cell trait and the other parent has two normal hemoglobin genes, the child has a 50% chance of inheriting the sickle cell trait and 50 percent chance of inheriting neither the trait nor the disease. In case one of the parents suffers from sickle cell anemia and the other parent happens to have normal hemoglobin genes, the child has a 100 percent risk of inheriting sickle cell trait. Furthermore, if one of the parents has sickle cell disease while the other parent possesses sickle cell trait, there is a 50 percent likelihood that the child will inherit sickle cell disease and a 50 percent chance that the child might inherit sickle cell disease.
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Sickle cell anemia has several presenting symptoms. One of the major symptoms is a vaso-oclusive crisis. It is mainly caused by the obstruction of blood capillaries by the sickle-shaped blood cells, which causes the blocking of the blood flow to body organs. This mainly makes patients suffering from this disease experience pain, ischemia and organ damage. Another symptom is pain in the spleen. This condition is known as splenic sequence crisis. The abdomen of a patient becomes enlarged, bloated and hard. Another symptom of sickle cell anemia is the reduction in the blood hemoglobin level. This is caused by a fast rate of red blood cells breakdown. Pulmonary hypertension is also common in patients suffering from sickle cell anemia. This causes the right ventricle of the heart to strain, making the patients have shortness in breath wheel exercising, thus causing decreased accidence tolerance (Medline Plus, 2011). Patients suffering from this disease also lose protein and blood cells while urinating. This condition is known as chronic renal failure. Doctors have also noted that patients suffering from sickle cell anemia have swellings in their hands and feet. High fever follows these swellings and doctors have attributed these swellings to be caused by sickle cells blocking blood vessels located in the feet. Patients with this disease also have jaundice. This symptom includes yellowing of the skin, eyes or mucus membranes of these patients. Another symptom of sickle cell anemia is acute chest syndrome. It makes the patients experience frequent coughing, difficulty in breathing and chest pains. Doctors have also established that patients suffering from sickle cell anemia experience eyesight worsening. Sickle cells block the blood vessels transporting blood to eye, which is why the retina becomes damaged. Young patients suffering from sickle cell anemia are also attacked by many infections such as pneumonia.
Sickle cell anemia has many treatment modes. One of them is the prophylactic therapy. Prophylactic measures include immunization against pneumococcal infection, penicillin prophylaxis and folate administration. According to a research conducted by medical practitioners, prophylactic therapy has reduced mortality rate among children suffering from sickle cell anemia. Patients suffering from sickle cell anemia can also receive treatment through red cell transfusion. Transfusion of red cells is extremely important, especially if the patient has a vaso-occlusive crisis. Doctors conduct transfusion if patients show dyspnea, postural hypotension, high output cardiac failure, and cerebral dysfunction (Aliyu, Tumblin & Kato, 2008). However, this form of treatment often implies a number of complications, such as acute lung injury, stroke and transfusion reactions. Medical experts recommend that patients suffering from sickle cell anemia should be given hydroxyurea. This drug increases hemoglobin F levels, boosts water content in red cells, alters adhesion of red blood cells to endothelium and microvascular navigation. Treatment using this drug is proved to reduce the adult mortality rate by 40%. However, scientists have also adopted new genetic approaches to treat sickle cell disease. One of these approaches is hematopoietic stem cell transplantation for sickle cell disease. In this approach, scientists use a combination of cyclophosphamacide and busulfan. This form of treatment can be crucial for patients suffering from acute chest syndrome, vaso-occlusive crisis and avascular bone necrosis. Indeed, patients who undergo successful hematopoiec stem cell transplant show stable mixed chimerism and improved survival. However, ethical issues arise in the process of testing and treatment of sickle cell anemia. In specific, there is evidence that some patients develop immune complications when they test new methods of treating this disease. In addition to this, critics argue that stem cell transplant is a form of abortion since an embryo may die when stem cells are harvested from it.
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Some discoveries and beliefs about sickle cell anemia have a historical perspective. As it was mentioned, cases of sickle cell trait are believed to be higher in African Americans compared to other races. This has a historical perspective, since researchers discovered the absence of spleen in an autopsy carried on a runaway slave. In addition to this, medical literature in Africa described sickle cell disease as children who come and go, since it caused a high infant mortality rate. Black people also used tar soap to cover those blemished because of sickle cell sores, which allows to state that this disease is common among the blacks. In 1904, James Herrick, a professor of medicine, explained sickle cells (News Medical, 2012). This was after his intern claimed that cells in the blood of his patient known as Walter Clement Noel had peculiar elongated and sickle-shaped cells. Noel suffered several attacks from muscular rheumatism and bilious attacks and in 1916, but later he died of pneumonia. These symptoms match the symptoms caused by sickle cell anemia and it is clear that it was sickle cell anemia that caused his death. The disease was named sickle cell anemia by Vernon Mason in 1922. The first scientist to prove that sickle cell disease was caused by hemoglobin molecule abnormalities was Linus Pauling and his colleagues. Their discovery was important to the history of molecular biology, since they successfully linked genetic diseases to mutation of a particular protein.
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Several patient teaching topics related to patients suffering from sickle cell anemia exist today. An example of such topics is how common the sickle cell is. Patients need to know that sickle cell is, since it affects approximately 300,000 newborns in each year. Patients also need to know people who are most vulnerable to suffer from sickle cell anemia. This disease mostly affects African Americans, Native Americans, South East Asians and Whites. Patients also need to know what causes sickle cell disease. They need to know that sickle cell is not airborne and that it is an inherited condition. Thus, it is important to explain that patients suffering from sickle cell inherit hemoglobin S gene from one parent and abnormal hemoglobin from the other parent. Patients also need to know that if one parent has hemoglobin C trait and the other parent has hemoglobin S trait, there is a big chance that a child will be born having sickle cell anemia (John Hopkins Medicine, 2012). It is also imperative that patients knew several facts about sickle cell disease. A patient can live a normal and productive life as long as he receives early diagnosis, treatment of any complications that may face him and constant patient education. Moreover, a patient with the sickle cell anemia should avoid consuming alcohol or smoking cigarettes, since this will bring complications to their general health. For patients to prevent crisis that results from sickle cell anemia, it is important to drink plenty of fluid, avoid getting infections, avoid getting overheated or very cold and get enough oxygen. Moreover, they need to avoid emotional stress and demanding physical activities. A patient suffering from sickle cell anemia also needs to receive genetic counseling. When a child is screened and is it happens that it posses sickle cell traits, it is probable that at least one of the parents has sickle cell traits. Moreover, pregnant women need to know that it is common for women descending from racial groups with high prevalence of sickle cell gene are likely to possess sickle cell trait.
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