Essay - Introduction Sickle Cell Anemia is an Inherited Blood Disorder in...


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Introduction

***** cell anemia is an inherited blood disorder in which hemoglobin is defective (Genetic disease profile: Sickle cell **********). After hemoglobin molecules give up their oxygen, some cluster together and form long, rod-like structures. These structures cause red ***** cells to become stiff and assume a sickle shape that makes it difficult for them ***** squeeze through small blood vessels. As a result, they stack up and cause blockages that deprive organs ***** tissues of oxygen-carrying blood.

Sickle cell anemia affects millions world wide (Genetic ***** profile: Sickle ***** anemia). It is the most common among people whose ancestors come from sub-Saharan Africa; Spanish-speaking regions (South America, Cuba, Central *****); Saudi Arabia; India; and Med*****erranean countries such as Turkey, Greece, and Italy. In ***** Unites States, it affects around 72,000 *****, most of whose ancestors come from Africa. The disease occurs in about one in every 500 African-American births and one in every 1000 to 1400 Hispanic-American births. About two million Americans, or one in twelve African Americans, carry the sickle cell trait.

Genotypic Expressions

People have twenty-two identical chromo***** pairs with one ***** each pair inherited from the fa*****r, and ***** from the mother (How does ***** cell cause disease?, 2002). Mutation involving gene alteration in the exchange between a parent and child occurs only rarely. Most likely, sickle ***** disease depends on ***** genes ***** parents' the disease cannot be caught, acquired or otherwise transmitted. ***** disease is caused by a change ***** a single amino acid difference in the beta chain of hemoglobin. (Malaria, sickle cell anemia, ***** balancing selection).

Individuals with two copies ***** the sickle ***** of ***** gene ***** sickle ***** anemia (Malaria, sickle cell anemia and balancing selection). Heterozygotes -- individuals ***** one n*****mal ***** one mutant copy of the sickle gene ***** appear normal and do not manifest ***** disease except under very stressful conditions. However, these individuals are carriers of the sickle cell trait. Approximately ten percent ***** African Americans ***** carriers. In Africa and India, the frequencies of the disease and carriers are even higher de ***** protection against malaria that occurred for people with sickle cell trait discussed later in this paper.

Beta globin is a major component of adult hemo***** ***** its gene is located on chromosome 11 with more than 475 allelic variants (Ashley-Koch, Yang, and Olney, 2000). One of *****se variants, sickle hemoglobin (Hb S), is responsible ***** sickle cell disease. The most influential risk factor for ***** severity is ge*****ype (Sickle cell anemia - description). Individuals who ***** homozygous ***** the ***** ***** globin ***** (b S) have sickle ***** anemia (SS disease). Individuals with sickle *****eta thalassemia have a b S gene ***** ***** gene for beta thalassemia. If no ***** ***** is produced by the beta thalassemia *****, the individual has Sb o thalassemia (***** o thal). ***** s*****me normal ***** globin ***** produced ***** the ***** gene, ***** individual has Sb + thalassemia (***** + thal). In the case of hemoglobin

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