Premarital screening (testing) for Thalassemia and Sickle Cell Disease Essay

Premarital screening (testing) for Thalassemia and Sickle Cell Disease (CSD) - Essay Example The thalassemias are a group of heterogenous group of inherited disorders caused by genetic defects as a consequence of which decreased synthesis of either the alpha or beta chain of HbA occurs (Aster, 2007, pg.632). When deficient synthesis of beta chain occurs, it is known as beta-thalassemia and when alpha synthesis is affected, it is known as alpha-thalassemia. Sickle cell anemia is a type of disease characterized by production of defective hemoglobins because of which sickling of red cells occurs in certain conditions (Aster, 2007, pg.628). Thalassemia has a wide distribution, particularly in areas where malaria has been endemic like in the Middle East, Southeast Asia, India and China). It is most common around the Mediterranean Sea, especially in Italy and Greece (Al-Suliman, 2006). The prevalence of the ÃŽ ²-thalassemia gene is estimated to range between 0.01 to 0.15 in various areas of Saudi Arabia (Al-Suliman, 2006). Several reports from Arab countries indicate that ÃŽ ²-thalassemia carriers have common genetic abnormalities, and the frequency of this disorder varies from country to country in the Middle East and is reported as 1% to 15% (Al-Suliman, 2006). In a study by Karimi and colleagues (2002), the prevalence of beta-thalassemia trait was estimated to be 5-10%. Hemoglobin S is most common in persons of African ancestry. In some regions of Africa, it has been estimated that up to 40% of the population is heterozygous for hemoglobin S. The gene is also present in Mediterranean, Middle Eastern, and Indian popula tions. Ten percent of American blacks are estimated to be heterozygous and 1 in 650 as homozygous (Schwarting, 2007). The normal hemoglobin of humans contains 4 globin chains. These are denoted as 2 ÃŽ ± and 2 non-ÃŽ ± chains. There are 3 normal variants of hemoglobin based on the nature of the non-ÃŽ ± chains. The commonest variant is Hemoglobin A (ÃŽ ±2ÃŽ ²2) which accounts for 95% to 98% of the total in adults. The adults