Sickle Cell Anemia By: Virginia Myers, Emily Stein, and Caroline McGuire

Mrs. Geithner-Marron Period 1Due: 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).