Evelyn Martinez Biology 150
Thalassemia is a blood disorder caused by the inefficient production of hemoglobin. Hemoglobin are important protein in red blood cells. This dysfunction causes a decrease production of RBC that deliver Oxygen to all cells and organs in the body (Reference#1). The red blood cells live for up to 120 days; in contrast to Thalassemic RBC that have a shorter life span. This can cause the condition of anemia depending on the type of Thalassemia. The population affected with the Thalassemia traits has Mediterranean decent. It is common in Greece, Turkey, Africa, Asia and Mediterranean Countries (reference#2). Therefore, it is an autosomal recessive disorder inherited or pass down from the parents to the child. Both mother and father can be carriers of this gene. The child has a 1in 4 chances with a 25% chance of thalassemia major, 50% chance of inheriting any form of the carrier traits and 25% chance of normal genes being inherited (reference #4).
The molecular structure of a hemoglobin comprises of a globin group and heme group bound to a polypeptide chain. In addition, the globin group contains four subunit proteins made up of two Alpha chains and two beta chains. Within these globin, there’s four bonding site called Heme that contain Iron ion (Fe2); their function is to bond to and release oxygen depending on the demand (Reference #3). In Thalassemic individuals, this molecular structure within the protein hemoglobin is mutated or missing an alpha gene located on chromosome 16 or Beta globin gene located in chromosome 11(reference#4). Each parent contributes two alpha genes and one beta globin gene. The alpha globulin only produces half of the protein in comparison to the Beta globin. Therefore, there are four Alpha globin molecules versus two beta globin (reference #4)
There are three main types of thalassemia with four subgroups. In Beta thalassemia both gene are present in the cell but one beta globin is ineffective at producing the hemoglobin protein. Beta thalassemia has two subgroups; Thalassemia major also known as Cooley’s anemia and Thalassemia Intermedia. Individuals with Thalassemia major have the most severe form of this disease. These individuals are nonproductive in beta globin formation that cause severe anemia and require blood transfusions. Unfortunately, blood transfusion produces iron overload within the organs and is effectively treated with Iron chelators. In comparison, Thalassemia intermedia has only one nonfunctional gene and these individuals may not experience any symptom. To the contrary, Alpha thalassemia has four genes that are mutated or missing; they are categorized within two subgroups; hemoglobin H and Hydrops Fetalis (Reference #1). The difference between Hemoglobin H and Hydrops Fetalis is the number of alpha genes affected. While Hemoglobin H has three alpha genes absent or altered; Hydrops Fetalis is fatal with all tarnished or missing. Its critical condition affects the fetus and usually the individual is stillborn or dies shortly after birth. It’s one of three categorized as severe. Hemoglobin H has its own debilitating factors as well. Its signs and symptom are bone disease with hypertrophic malformation of cheek, forehead and Jaw; therefore, leading to an enlarge spleen, jaundice and malnourishment (reference #1).
Thalassemia can be diagnosed with a series of blood test and a smear. A hemoglobin electrophoresis help identifies abnormalities within the different types of red blood cells. Genetic testing is also available for those individuals with Mediterranean ancestry. A complete blood count can be used in combination with a blood smear that allows the hematologist to view the
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cells shape for abnormalities (reference#4). In addition, a Means Corpuscular Volume is part of the complete blood count and measures the size of the red blood cell (referenced 6). Thalassemic cell are microcytic in nature. Therefore, they’re inefficient at delivering oxygen to the cells in the body called anemia. Anemia symptoms includes shortness of breath, dizziness, fatigue, tachycardia, and headaches. It also causes the spleen to overstrain with the need to replace these cells, instigating the enlargement within the spleen. The spleen has two important functions hemopoiesis and filtration of abnormal blood cells. Unfortunately, it cannot do both at the same time. Therefore, since the demand is greater on hemopoiesis then the body these individuals becomes immune compromised. Vaccinations are important factor in preventing against infections and keeping these individuals healthy. The treatment for thalassemia depends on the type. Thalassemia major can be treated with blood transfusions in combination with chelation treatment that counteract iron overload that can be fatal. The Iron overload can cause cardiomyopathy, liver damage or organ failure (reference#7). These individuals need to limit their intake of iron rich foods such as meats, fish and certain green vegetables like spinach. A nutritionist can be consulted (reference#2). Although, Bone marrow transplants are risky; it has been a successful cure but requires a compatible bone marrow donor. Scientist are researching gene therapy that may be a potential cure in the future (reference#5). This gene therapy involves the insertion of a normal beta globin gene into the individuals bone marrow as a stem cell and precursor to produce these cells. In conclusion, Thalassemia major can be a severe disease that can be fatal, but individual can manage the disease under a physician’s care, treatment, and proper diet.
Reference 1- Thalassemia: causes, symptoms and diagnosis
Reference 2- Center of disease control and prevention -Facts about Thalassemia and a guide to living with thalassemia
Reference 3- Openstax A;P- The cardiovascular system: Blood chapter18
Reference 4- How do people get Thalassemia?
Reference 5- National Human Genome research institute- Learning about Thalassemia
Reference 6- Cooley’s Anemia Foundation- An Introduction to Beta-Thalassemia Major
What is Hemoglobin E? What is Hemoglobin H?
Reference 7- Cardiac Complications in Thalassemia Major by John C. Wood
Cardiac Issues in thalassemia- Cooley’s Anemia Foundation