Sickle Cell Anemia By: Virginia Myers, Emily Stein, and Caroline McGuire Mrs. Geithner-Marron Period 1 Due: Tuesday, February 8th, 2011

What is it? Treatable hereditary blood disease that occurs mainly among people of African, Caribbean, and Mediterranean descent. Characterized primarily by chronic anemia and periodic episodes of pain. The underlying problem involves hemoglobin, a component of the red cells in the blood In sickle cell anemia, the hemoglobin is defective. Unlike normal red cells, which are usually smooth and donut shaped, the sickle-shaped red cells cannot squeeze through small blood vessels; they are crescent shaped and clumped together. Instead, they stack up and cause blockages, that deprive organs and tissue of oxygen-carrying blood. (This causes the periodic episodes of pain.) One of the most well documented examples of an evolutionary process known as heterozygous advantage, an important means by which genetic variability is preserved Known as: Sickle-Cell Disease and Sickle-Cell Anemia

Causes Is caused by an error in the gene that tells the body how to make hemoglobin. Studies of the incidence of the disease in families led to recognition that the illness is manifested only in individuals who receive the sickle-cell allele from both parents. In most circumstances, individuals who inherit the sickle-cell allele from only one parent display no symptoms of the disease; however, they are carriers of the sickle-cell gene and may pay pass it on to their children. Caused by a mutation in a blood protein called beta globin and the mutation leads to changed in the shape and behavior of red blood cells Sickle-cell anemia affects millions of people throughout the world

Probability It is particularly common among people whose ancestors 1 in 500 African Americans has Sickle-Cell Anemia 1 in 900 Hispanic Americans has Sickle-Cell Anemia 1 in 58,000 Caucasian Americans has Sickle-Cell Anemia It is estimated that in the U.S., some 50,000 African Americans are afflicted with the most severe form of sickle-cell anemia. Overall, current estimates are that one in 1,875 U.S. African American is affected with sickle-cell anemia. One of the most commonly inherited diseases worldwide, and pain is the most important symptom of the disease.

Symptoms Symptoms appear six months after birth; the severity of the illness varies widely among individuals. Some develop severe anemia as deformed red blood cells are removed. One of the most important symptoms of the disease is pain; it is often described as deep, gnawing, and throbbing Swelling of hands and feet, fatigue, paleness, and shortness of breath Pain that occurs unpredictably in any body organ or joint Eye problems, yellowing of skin and eyes Delayed growth and puberty in children and often a slight build in adults Infections and stroke Infants and younger children and suffer with fever and abdominal pain; adolescents and young adults more commonly develop leg ulcers and aseptic necrosis. Usually due to injury of bone, muscle, or internal organs.

Being Tested A simple blood test called the hemoglobin electrophoresis can be done by your doctor or local sickle cell foundation. This test will tell you if you are a carrier of the sickle cell trait or if you have the disease. The three most common different types: Hemoglobin SS or Sickle Cell Anemia, Hemoglobin SC Disease, and Hemoglobin Sickle Beta- thalassemia. Each of these can cause sickle cell pain episodes and complications, but some are more common than others. All of these may also have an increase in fetal hemoglobin which can protect the red cell from sickling and help prevent complications. The medication hydroxyurea also increases fetal hemoglobin. Only available cure is a bone marrow transplant, which is a high risk operation.

Diagnosed Testing is usually performed on a smear of blood using a special low oxygen preparation, referred to as sickle cell prep. The disease can be confirmed by specifically quantifying the types of hemoglobin present using a hemoglobin electrophoresis test. Prenatal diagnosis (before birth) of sickle cell anemia is possible using amniocentesis or chronic villus sampling. The sample is then tested for DNA analysis of the fetal cells.

Works Consulted “Pain in Sickle Cell Disease (Sickle Cell Anemia).” University of Michigan HealthSystem. 2011. <www.med.umich.edu> (24 January 2011). “Sickle Cell Anemia.” National Heart Lung and Blood Institute Diseases and Conditions Index. 2011. <www.nhlbi.nih.gov> (24 January 2011). “Sickle Cell Disease (Sickle Cell Anemia).” MedicineNet.com. 2011. <www.medicinenet.com> “Sickle Cell Disease.” Sickle Cell Information Center. 28 April 2010. <scinfo.org> (23 January 2011). “Sickle Cell Disease.” Your Genes Your Health. <yourgenesyourhealth.org> (23 January 2011).