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

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Sickle cell anemia is an inherited blood disorder in which hemoglobin is defective (Genetic disease profile: Sickle cell *****emia). After ***** 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 to squeeze through small blood vessels. As a result, they stack up and cause blockages ***** deprive organs and tissues of oxygen-carrying *****.

***** cell anemia affects millions world wide (Genetic ***** pr*****ile: Sickle ***** anemia). It is the most common among people whose ances*****rs come from sub-Saharan Africa; Spanish-speaking regions (South America, Cuba, Central *****); Saudi Arabia; India; ***** Med*****erranean countries such as Turkey, Greece, and *****aly. In ***** Unites States, it ***** around 72,000 *****, most of whose ancestors come ***** 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 ***** in twelve African Americans, carry the ***** cell tra*****.

Genotypic Expressions

People have twenty-two identical chromo***** pairs with one of each pair inherited from the father, and one from the mother (How does sickle cell cause disease?, 2002). Mutation involving gene alteration in the exchange between a p*****rent and child ***** only rarely. Most likely, sickle cell ***** depends on ***** *****s from parents' the disease cannot be caught, acquired or otherwise **********. The disease is caused by a ch*****nge in a s*****gle amino acid difference in the beta cha***** of hemoglobin. (Malaria, sickle ***** anemia, ***** balancing selection).

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

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


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