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Sickle Cell Anemi A Group Of Diseases Essay

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Sickle Cell Anemia

Introduction: Sickle cell disease is a group of diseases in which the affected individual has at least one copy of hemoglobin S (HbS). Sickle cell anemia is a type of sickle cell disease in which the patient inherits 2 copies of hemoglobin S (genotype HbSS). There are other examples of sickle cell disease; they include- HbAS, HbSC, and HbS beta thalassemia (National Heart, Lung, and Blood Institute). The focus of this article would be on Sickle cell anemia. Sickle cell anemia is seen predominantly among Africans but is also seen in people of Mediterranean origin and the Middle East. It occurs in approximately 1:500 African American births and 1:36,000 Hispanic American births. About 2 million people in the United States have acquired the sickle cell trait (U.S. Department of Health and Human Services). The disease is caused by a point mutation in position 6 of the beta subunit of the hemoglobin gene which results in substitution of the amino acid valine in place of glutamic acid. There is a single nucleotide substitution (A to T) in the codon for amino acid 6. The change converts a glutamic acid codon (GAG) to a valine codon (GTG) (National Heart, Lung, and Blood Institute).

Pathophysiology of sickle cell anemia
Sickle cell anemia is characterized by chronic hemolytic anemia punctuated with acute episodes known as the sickling crises. The presence of valine in HbS makes the hemoglobin molecule dysfunctional. In periods of hypoxia, the
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