ThalassemiaThalassemia includes a number of different forms of anemia (red blood cell deficiency). The two main types are called alpha and beta thalassemias, depending on which part of an oxygen-carrying protein (called hemoglobin) is lacking in the red blood cells. Humans normally have 4 functional alpha globin genes (2 from each parent) and 2 functional beta globin genes. Alpha-thalassemia ( Beta-thalassemia is characterized by reduced synthesis of the hemoglobin beta chain that results in microcytic hypochromic anemia, an abnormal peripheral blood smear with nucleated red blood cells, and reduced amounts of hemoglobin A. There may be a range of clinical symptoms. Individuals with thalassemia major generally have clinical symptoms within the first 2 years of life. They have severe anemia and hepatosplenomegaly. Untreated children have severe failure to thrive and shortened life expectancy. Transfusion programs and chelation therapy allow for normal growth and development. Life expectancy can be into the fifth decade for treated individuals. The presentation of Thalassemia intermedia is at a later age with milder anemia that only rarely requires transfusion. Heterozygotes may be slightly anemic but are clinically asymptomatic. Carriers are often referred to as having thalassemia minor (or -thalassemia minor). Beta-thalassemia is seen more commonly in individuals of Mediterranean descent. A couple presents to you for preconceptional counseling and would like to know whether they can both have genetic screening for thalassemia to make sure they aren't carriers.
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