Sickle Cell Anemia

Sickle cell anemia is a genetic disease that plagues millions of people around the world. It is most common in Africa, South America, Central America, the Caribbean, the Mediterranean, India, and Saudi Arabia ("Sickle," Disease). In the United States of America alone, there are over 70,000 people who have sickle cell anemia; many of these individuals are African American ("Sickle," Disease). About one out of every 500 African American births will produce a child with sickle cell anemia. In the Hispanic population, about one out of every 36,000 births will produce a child with sickle cell anemia ("Sickle, Disease). The number of carriers is even more astounding, with an estimated two million Americans carrying the trait (Fahner). With so many people serving as carriers, it is shocking to see such a lack of awareness about the disease itself.

Sickle cell anemia causes blood cells that are normally round and doughnut-shaped to take on more of a rigid and sickle-shaped appearance (Fahner). The description "sickle-shaped" is actually derived from the way the cells look. A sickle is an old hand-held farming tool used to harvest cereal crops.

Normal cells have hemoglobin A, which is loaded with iron that gives blood its red appearance ("Sickle," Disease). Hemoglobin also plays a crucial role in transporting oxygen and removing carbon dioxide inside of the body. Sickle cells create a different form of hemoglobin, known as Hemoglobin S, which gives the cells their mutated shape. The "S" in Hemoglobin S stands for "sickle" ("Sickle," Mayo). According to the Diseases and Conditions Index, the sickle shape gives the cell a more "stiff and sticky" texture. This form makes it harder for the cells to pass through narrow blood vessels. When the blood cells cannot pass as easily as normal cells, it can create a backup in the flow of the vessel. The slower flow may block blood delivery to organs and extremities.

The Diseases and Conditions Index, published by the National Heart, Lung, and Blood Institute, also states, "Sickle cell anemia is one type of anemia. Anemia is a condition in which your blood has a lower than normal number of red blood cells." The marrow, which is made inside of the bones, creates red blood cells. Sickle cell anemia affects many characteristics of blood cells, one of which is the longevity of each blood cell. Normal blood cells die in 120 days ("Sickle," Disease). In contrast, sickle cells, which are more fragile, usually die in 10-20 days. Therefore, this disease earns the name anemia, because the rapid death of red blood cells causes a lower than normal red blood cell count.

Sickle cell anemia is inherited through a pattern known as autosomal recessive inheritance ("Sickle," Mayo). Affected individuals have two copies of the sickle cell gene- one from each parent. Because this disease is recessive, two carrier parents can have an affected child. A punnett square can easily and visually depict the possible progeny of two carrier parents. In a punnett square using "A" as a dominant allele and "a" as a recessive allele, "A" causes production of normal-shaped cells, while "a" causes sickle-shaped cells. Therefore, the parents have a 25% chance of having a child who is not a carrier and does not have the disease. They have a 50% chance of having a child who is a carrier, but does not have the disease. They have a 25% chance of having a child who is afflicted with sickle cell anemia and therefore carries the gene. The chances of each outcome are the same in each pregnancy for these parents.

Because there is double the chance of being a carrier as there is for being an affected individual, there are many people who never know that they are carriers of the disease. Therefore, it is recommended that people who are unsure get tested (Fahner). For newborns that have the disease, early diagnosis is extremely important. It is so important that currently all states mandate that newborns go through a screening process ("Sickle," Disease). If the primary screening shows Hemoglobin S, a second test is done to confirm its presence. With this standard screening, doctors use hemoglobin electrophoresis to look for Hemoglobin S in the individual's blood. It is also possible to diagnose the disease before birth. This technique requires a sample of amniotic fluid or placenta tissue.

Great lengths are taken to diagnose individuals, and specifically newborns, with sickle cell anemia because it may be hard to spot at first. Newborns frequently do not show any signs of sickle cell anemia until they are beyond four months of age ("Sickle," Disease). Another problem with the signs of sickle cell anemia is that there is a great deal of variable expressivity. Delayed growth is one of the many symptoms that can occur because of the disease. Growth is sometimes slowed and teens will often reach puberty later than their peers (Fahner). This is because the sickle cells are not as efficient at transporting oxygen and nutrients throughout the circulatory system ("Sickle," Disease). Other symptoms include chronic pain and fatigue, vision problems, sickle cell crisis, shortness of breath, dizziness, headache, coldness of hands and feet, pale skin, chest pain, and fragile bones ("Sickle," Disease).

There are also many complications that arise from sickle cell anemia. The Sickle Cell Disease Association of America states, "Tissue that does not receive a normal blood flow eventually becomes damaged. This is what causes the complications of sickle cell disease". Some of these complications include the following: hand-foot syndrome, splenic crisis, infections, acute chest syndrome, pulmonary arterial hypertension, stoke, priapism, gallstones, multiple organ failure, and jaundice ("Sickle," Disease).
The symptoms and complications caused by sickle cell anemia frequently require treatment to help the afflicted individual lead a normal life. There is no complete cure for sickle cell anemia. Instead, there are treatments that can lessen the severity of the symptoms. Bone marrow transplants, blood transfusions, and supplemental oxygen are just a few of the clinical treatments available ("Sickle," Disease). Supplemental oxygen adds oxygen to the blood and helps the individual breathe more easily ("Sickle," Mayo). It is specifically helpful to individuals that have acute chest syndrome or sickle cell crisis ("Sickle," Mayo). There are also some in-home treatments that include supplements of folic acid, butyric acid, clotrimazole, or nitric oxide ("Sickle," Mayo). Folic acid facilitates the production of new red blood cells, which can help offset rapid degeneration of blood cells (Fahner). Nitric oxide helps to keep blood vessels open and reduces the stickiness of red blood cells ("Sickle," Mayo). Apart from current treatments, gene therapy is rapidly becoming a possible alternative. It has already been used to treat sickle cell anemia in mice (Trivedi). Human clinical trials have not yet been started, but the research is coming close.

Modern science provides many treatments and alternatives that allow people diagnosed with sickle cell anemia to live longer. While sickle cell is a recessive lethal, it is difficult to see, because countless people are now living beyond their forties. In the article, Life Expectancy for People with Sickle Cell Disease, it is estimated that in the United States, "Men with sickle cell disease live for about 42 years, on average. For women, the average is 48 years". The article goes on to state, "In some parts of Africa, where good health care isn't always available, about half of children with sickle cell disease die before their first birthday".

There are many people afflicted with sickle cell anemia around the world, and access to treatment, for some people, is not a real possibility. This is why finding a cure is so important, and the first step to finding a cure is awareness. As interest grows for the disease and the symptoms associated with it, so will funding. Many of the most prominent and devastating diseases in the world are genetic, and an understanding of genetics is vital in the process for global awareness.

Works Cited

Fahner, James . "Sickle Cell Anemia." Teens Health. Jun. 2007. 18 Mar. 2009.

"Life Expectancy for People with Sickle Cell Disease." The Guardian. 4 Dec. 2008. 18 Mar. 2009.

"Sickle Cell Anemia." Diseases and Conditions Index. Aug. 2008. 18 Mar. 2009.

"Sickle Cell Anemia." Mayo Clinic. 28 Mar. 2007. 18 Mar. 2009.

"Sickle Cell Disease." Genetics Home Reference. 6 Mar. 2009. 18 Mar. 2009.

Trivedi, Bijal P. "Gene Therapy Used to Treat Sickle Cell Disease in Mice."
National Geographic Today 13 Dec. 2001. 18 Mar. 32.

"What is Sickle Cell Disease?." Sickle Cell Disease Association of America. 18 Mar. 2009.