Sickle+Cell+Anemia

//​Sickle Cell Anemia//  Krysta Lewis May 18, 2010

​ Abstract:  The purpose of this research is to analyze genetically transmitted diseases, specifically emphasizing on sickle cell anemia to better understand the inheritance of mutated genes through family genetics. Sickle cell anemia is passed down to thousands of people every year, prominently African Americans. This paper will provide an in-depth examination of sickle cell anemia, how the genes are passed down, as well as the causes, symptoms, diagnosis, prognosis and treatments.  Introduction: The error in the hemoglobin gene of sickle cell trait initially resulted from a genetic mutation that occurred thousands of years ago in the regions of Africa, South and Central America, the Mediterranean, Middle East, and India. As an environmental immune trait, the sickle cell gene was found in areas where the malaria was rampant. Those who possessed one sickle hemoglobin gene, and thus carried the gene for sickle cell trait, had a survival advantage over those who had normal hemoglobin genes. Studies found those with one abnormal hemoglobin gene survived the malaria epidemic and passed the sickle hemoglobin trait to their offspring, providing a larger survival advantage. Where malaria is not prevalent, the gene for sickle hemoglobin gene no longer provides a survival benefit, which in turn causes a threat to the carrier’s children who may inherit both abnormal sickle hemoglobin genes and posses sickle cell anemia (Massimini, 2000, pg. 300-302). The trait still persists where malaria is not found and the National Heart Lung and Blood Institute suggests that about 1 in every 12 African Americans has the sickle cell anemia trait (National Heart Lung and Blood Institute, 2008). Sickle cell anemia overall became an interest to me when a professor of mine, an African American, explained he carried the mutated gene for the disease, but did not inherit sickle cell anemia. Although I had a basic idea of the anemia, I wanted to fully understand the complexity of the disease and how one can possess the mutated gene trait, without actually having sickle cell anemia passed down to them. Discussion: **What is Sickle Cell Anemia?** Sickle cell anemia is an inherited blood disorder in which causes hemoglobin, the protein component of red blood cells that carries oxygen from the air in our lungs throughout our body to become deoxygenized, resulting in a “sickle”, or crescent shaped. The single base substitution at position six of the amino acid valine in place of glutamic acid causes the normal hemoglobin A molecule to become hydrophobic, creating a hemoglobin S molecule instead. The reduction of solubility of the hemoglobin molecule promotes the formation of large insoluble aggregates (National Library of Medicine - National Institutes of Health, 2010). As demonstrated in the diagram above, normal hemoglobin allows red blood cells to flow freely with ease through blood vessels. When there is abnormal hemoglobin, red blood cells become stiff, sticky and tend to clump up in blood vessels, causing block of blood flow and lack of oxygen to the body’s tissues(National Heart, Lung, and Blood Institute, 2008). Normal red blood cells usually live for 120 days in the bloodstream. On the other hand, sickled red blood cells only last for about 10 to 20 days. Because sickled red blood cells cannot be replaced fast enough to have a sufficient red blood count, a condition called anemia is given (Massimini, 2000, pg. 299). .  To further understand Sickle Cell Anemia, watch the short clip below. media type="youtube" key="9UpwV1tdxcs" height="385" width="480" (Garland Science Publishing, 2004)

 Sickle cell anemia is passed down through family lineage. Sickle cell anemia, like most all genetically transmitted diseases, is a result of a genetic mutation. In other words, the gene for sickle cell must be inherited from each parent. Sickle cell anemia is a recessive disease in which two recessive genes of hemoglobin S, one from each parent, are needed in order to possess the disease. Two copies of the sickle cell gene are needed in order to form the abnormal hemoglobin gene found in sickle cell anemia (National Heart, Lung, and Blood Institute, 2008). When each parent possesses the sickle cell trait, there is a 1 in 4 chance the offspring will receive sickle cell anemia. The inherited defective gene tells the body to make the abnormal hemoglobin S, which results in abnormal deoxygenated red blood cells. Individuals that receive an individual sickle cell gene from only one parent will not possess the disease or usually express symptoms. Instead, the carrier of a single gene will have an increased chance of passing the sickle hemoglobin gene on to their children (Massimini, 2000, pg. 300).
 * What Causes Sickle Cell Anemia?**

In addition to family inheritance, race and culture are also critical factors in possessing the genes for the disease. African Americans are especially at the highest risk for the disease and according to the American Sickle Cell Association (2000), sickle cell affects over 72,000 Africa Americas. In addition, 1 in every 375 African Americans is born with sickle cell anemia (Reid, 2006, pg. 1). Other regions strongly affected include whose families come from Africa, South or Central America (especially Panama), Caribbean islands, Mediterranean countries (such as Turkey, Greece, and Italy), India, and Saudi Arabia (National Heart, Lung, and Blood Institute, 2008). **What are the Symptoms of Sickle Cell Anemia?**  “Sickle cell anemia is a life-long, chronic, debilitating disorder that impacts on the ability to carry out social roles” ( Reid, 2006, pg. 2). Millions of people throughout the world are affected by the disease (Massimini, 2000, pg.302). Depending on person to person, there is not specific pattern of symptoms. Symptoms can vary from temporary and mild to long term and severe. However, the basic problem lies under the fact that sickle shaped blood cells cause blockage of blood flow (Massimini, 2000, pg. 302). This in turn can result in a variety of several symptoms throughout the body. Sickle Cell Anemia is present at birth, but signs and symptoms may not show until four months of age. Typical symptoms are linked to the anemia and pain of the disease. More severe symptoms are related to the long term complications of the disease (National Heart, Lung and Blood Institute, 2008) <span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">.

<span style="font-family: Georgia,serif; font-size: 12pt;">Symptoms linked to anemia include: <span style="color: black; font-family: Georgia,serif; font-size: 12pt;">( National Heart, Lung and Blood Institute, 2008).
 * <span style="font-family: Georgia,serif; font-size: 12pt;">Shortness of breath
 * <span style="font-family: Georgia,serif; font-size: 12pt;">Dizziness
 * <span style="font-family: Georgia,serif; font-size: 12pt;">Headache
 * <span style="font-family: Georgia,serif; font-size: 12pt;">Coldness in the hands and feet
 * <span style="font-family: Georgia,serif; font-size: 12pt;">Pale skin
 * <span style="font-family: Georgia,serif; font-size: 12pt;">Chest pain

Symptoms linked to pain can be unpredictable in any body organ or joint where the sickled blood cells may flow. Some patients experience a period of painful episodes, also called crises, in which may only occur once a year or as many as 15 times a year. Pain is one of the principal symptoms in sickle cell anemia in both adults and children (Massimini, 2000, pg 302-3).

<span style="color: #000000; font-family: Georgia,serif; font-size: 12pt; line-height: 115%;">Prominent regions of pain include: <span style="color: #000000; font-family: Georgia,serif; font-size: 12pt;">(National Heart, Lung and Blood Institute, 2008) <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">.
 * <span style="color: #000000; font-family: Georgia,serif; font-size: 12pt;">Bone pain
 * <span style="color: #000000; font-family: Georgia,serif; font-size: 12pt;">Abdominal pain
 * <span style="color: #000000; font-family: Georgia,serif; font-size: 12pt;">Ulcers
 * <span style="color: #000000; font-family: Georgia,serif; font-size: 12pt;">Hand- foot syndrome. Blood Vessels in hands and feet become blocked causing pain and swelling (Massimini, 2000, pg. 302).

<span style="font-family: Georgia,serif; font-size: 12pt;">Complications of sickle cell anemia include: <span style="color: black; font-family: Georgia,serif; font-size: 12pt;">( National Heart, Lung and Blood Institute, 2008) <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt;">.
 * <span style="font-family: Georgia,serif; font-size: 12pt; line-height: 115%;">Splenic Crisis. The spleen filters out abnormal red blood cells to fight infection. In some cases the spleen may trap too many cells that should be entering the bloodstream. This can lead to anemia.
 * <span style="font-family: Georgia,serif; font-size: 12pt; font-weight: normal;">Infections. Pneumonia, influenza, meningitis, and hepatitis are common infections and causes of death of sickle cell anemia
 * <span style="font-family: Georgia,serif; font-size: 12pt; font-weight: normal;">Acute Chest Syndrome. Similar to Pneumonia, this complication of sickle cell anemia is caused by sickled cells in the lungs
 * <span style="font-family: Georgia,serif; font-size: 12pt; line-height: 115%;">Pulmonary Arterial Hypertension. Damage to small blood vessels makes it extremely difficult for the heart to pump blood to the lungs.
 * <span style="font-family: Georgia,serif; font-size: 12pt; font-weight: normal;">Delayed Growth and Puberty in Children. The shortage of normal red blood cells causes a delay in growth and puberty.
 * <span style="font-family: Georgia,serif; font-size: 12pt; font-weight: normal;">Stroke.
 * <span style="font-family: Georgia,serif; font-size: 12pt; font-weight: normal;">Eye Problems. Sickled cells can block the small vessels that deliver the oxygen rich blood to the eyes.
 * <span style="font-family: Georgia,serif; font-size: 12pt; font-weight: normal;">Priapism. Sickle cell anemia may cause males to have painful and unwanted erections.
 * <span style="font-family: Georgia,serif; font-size: 12pt; line-height: 115%;">Gallstones.
 * <span style="font-family: Georgia,serif; font-size: 12pt; font-weight: normal;">Ulcers on the Legs. The cause of sickle cell ulcers is not clear. Though, the leg sores occur more often in males than females.
 * <span style="color: black; font-family: Georgia,serif; font-size: 12pt;">Multiple Organ Failure: This is rare, but very serious. Multiple organ failure occurs when a sickle cell crisis causes two out of the major three organs (lungs, liver and kidney) to fail.

<span style="display: block; font-family: Georgia,serif; font-size: 12pt; text-align: center;">**<span style="color: #000000; font-family: Georgia,serif; font-size: 12pt;">How is Sickle Cell Anemia Diagnosed? ** <span style="color: #000000; font-family: Georgia,serif; font-size: 12pt;">According to the National Heart, Lung and Blood Institute(2008), early diagnosis of sickle cell anemia is critical in receiving proper treatment, especially with children. As a requirement, the United States has mandated all newborns be tested for sickle cell anemia (National Heart, Lung and Blood Institute, 2008). The most widely used diagnostic test is the hemoglobin electrophoresis, which tests for the count of oxygen-carrying protein (hemoglobin) in the blood (Massimini, 2000, pg.304). Other tests include the sickle cell test and complete blood count (National Library of Medicine - National Institutes of Health, 2010).

<span style="display: block; font-family: Georgia,serif; font-size: 12pt; text-align: center;">**How is Sickle Cell Anemia Treated?**

<span style="color: #000000; display: block; font-family: Georgia,serif; font-size: 12pt; text-align: left;">Although there is no true cure for sickle cell anemia, treatments consist of pain intervention, infusion therapy and the multiple effects of organ failure (Reid, 2006, pg.2). Primary treatments include releiving pain, preventing infections, eye damage, strokes, and major complications (National Heart, Lung and Blood Institute, 2008). The management and control of sypmtoms is a critical factor in the treatment process. Antibiotics and pain medications are often prescribed to control and prevent pain or infection. Hydroxyurea (Hydrea) in many cases is prescribed to control several pain episodes, including chest pain and difficulty breathing. Other methods of long term treatment are gene therapy and bone marrow transplants(U.S. Department of Health and Human Services, 2009).

<span style="display: block; font-family: Georgia,serif; font-size: 14pt; text-align: center;">**What is the Prognosis of Sickle Cell Anemia?**

<span style="font-family: Georgia,serif; font-size: 12pt;">The National Heart, Lung and Blood Institute (2008) suggests "with good health care, many people who have sickle cell anemia can live productive lives. They also can have reasonably good health much of the time and live longer today than in the past. Many people who have sickle cell anemia now live into their forties or fifties, or longer." Maintaining a healthy lifestyle is one of the key factors to a healthy life with sickle cell anemia. Taking steps to control and prevent unwanted complications is also exremely important.

<span style="color: #f91a1a; display: block; font-family: Georgia,serif; font-size: 14pt; text-align: left;">Literature Cited <span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 200%;">Massimini, K. (2000). //Genetic disorders sourcebook// (L. L. Harris, Ed., 2nd ed.). Detroit, MI: Frederick G. Ruffner, Jr. Print.

Reid, Shelia A. (2006). Lived experience of young adults living with sickle cell anemia. M.S. dissertation, D'Youville College, United States -- New York. Retrieved May 17, 2010, from Dissertations & Theses: The Sciences and Engineering Collection.(Publication No. AAT 1433258).

Sickle Cell Anemia. (2009, July). // U.S. Department of Health and Human Services. // <span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 115%;">//National Library of Medicine - National Institutes of Health.// Web. // ( //<span style="color: black; font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 200%;">[] ).

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 200%;">Sickle Cell Anemia (2008). National Heart, Lung, and Blood Institute. Web. // ( //<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: 200%;">[]). <span style="font-family: 'Times New Roman',Times,serif; font-size: 12pt;"> __Sickle Cell__. Alberts, et al., Garland Science Publishing. 2004. Film. ([]).

<span style="color: #000000; font-family: 'Times New Roman',Times,serif; font-size: 12pt;">Tortora,Gerard J., Berdell R. Runke, and Christine L. Case. Microbiology: An Introduction. San Francisco, CA: Pearson Benjamin Cummings, 2010. Print.