Beta-thalassemia: Year of the Zebra

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We may take for granted how important ground vehicles are to the flow of daily life: they transport people, deliver crucial goods, and much more. They are designed for their respective tasks efficiently, but how would these vehicles work with one or two missing wheels? This is an analogy for the fundamental problem facing patients with beta-thalassemia. Found in our red blood cells, hemoglobin is responsible for the transport of oxygen and carbon dioxide throughout the body. Adult hemoglobin is composed of four globin chains (two alpha and two beta chains), the 'wheels' of the hemoglobin vehicle. In beta-thalassemia, a mutation in the gene that gives the instructions for beta chain production occurs, resulting in faulty, inefficient, or absent beta chains. This results in the defective formation of red blood cells, a lack of functional hemoglobin, and the failure to deliver sufficient amounts of oxygen to the body. Symptoms and severity of beta-thalassemia vary greatly from one person to another depending on the degree of impairment of beta globin chain production. In the most serious form, severe anemia develops resulting in fatigue, weakness, shortness of breath, dizziness, headaches, and jaundice. There may also be spleen and liver enlargement, and in an attempt to overcompensate for inefficient red blood cell production, the bone marrow may expand, damaging bone structure to the point of making them brittle. Beta-thalassemia is an autosomal recessive disorder. The incidence is estimated to be approximately 1 in 100,000 individuals. The disorder is particularly prevalent in the Mediterranean basin, Africa, and Asia. To learn more about the mechanisms and treatment of beta-thalassemia, watch the dedicated Osmosis video on YouTube and Osmosis.org