The topic that I am learning about is Sickle Cell Anemia, a hereditary disease which
affects red blood cells. Throughout this research paper, I will discuss what exactly it
is, how it is caused, any known treatments or cures, and many other facts that are
important in this disease.
Sickle Cell Anemia is a health problem throughout the world. More than 250,000
babies are born worldwide with this inherited blood cell disorder
(http://www.medaccess.com/h_child/sickle/sca_01.htm). The disorder causes red blood cells
to extend into a sickle shape which clogs the arteries.Persistant pain and
life-threatening infections result from the illness. About one in 400 black newborns in
the U.S. have sickle cell anemia. And one in 12 black Americans carry the sickle cell
trait (http://www.medaccess.com/h_child/sickle/sca_01.htm). This leaves a good chance
that the parent with the trait can pass the defect onto offspring although their own
health is not harmed.
The cause of sickle cell anemia is rather simple but it leaves a life threatening
affect. Anyone who carries the inherited trait for sickle cell anemia, but doesn't have
the disorder, is actually protected from a severe form of malaria. This helped the
children in countries where malaria was a problem, to be able to survive against that
disease. What happened to those children? They grew up, had their own children and ended
up passing the gene for sickle cell anemia onto their offspring.
This disease is a hereditary blood disorder that affects the red blood cell. Red
blood cells contain a protein called hemoglobin which transports oxygen from your lungs
to every part of your body. Hemoglobin's oxygen carrying ability is essential for living
but if there is a structural defect on the pigmented molecule, it can be fatal. When a
normal red blood cell distributes its
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oxygen, it has a disc shape. But when an affected red blood cell containing sickle cell
hemoglobin releases its oxygen, the image of the cell changes from a disc shape to a
sickled shape. In hemoglobin, there are four chains of amino acids. Two are know as alpha
chains, and two are called beta chains. In a normal hemoglobin, the amino acid in the
sixth position on the beta chain is known as glutamic acid (refer to diagram 1.1 on page
6). During sickle cell anemia, the glutamic acid is pushed out of its place and replaced
with another amino acid called vialine(refer to diagram 1.2 on page 6). This simple
substitution has devastating consequences.
Hemoglobin molecules that contain the beta chain defect stick to one another instead
of staying separate after releasing oxygen. This forms long, rigid rods inside the red
blood cells. The rods cause the normally smooth and disc shaped blood cells to take on a
sickle shape. When this happens, the blood cells lose essential ability to deform and
squeeze through small blood vessels and arteries. The sickle cells becomes stiff and
sticky which clog vessels, depriving tissue from receiving a sufficient blood supply.
This change makes the hemoglobin less soluble in water. When a person is deprived of
oxygen, the hemoglobin molecules join together and form fibers. The fibers cause the
blood cells to change shape.
Sickle hemoglobin and normal hemoglobin carry the same amount of oxygen but there are
two major differences between the two kinds of cells. The normal hemoglobin is found in
only disc shaped red blood cells that are soft, which permits them to easily flow through
small blood vessels. Diseased red blood cells are sickle shaped and are very hard which
tend to get stuck in small blood vessels and stop the flow of blood.
The other difference between the two cells is their longevity. Sickle cells do not
live as long as
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normal cells. Normal healthy cells can survive for about 120 days , while the more
fragile sickle cells can survive for about 60 days or even less. The body cannot make
new red blood cells as fast as it loses sickled blood cells. A sickle cell patient has
fewer red blood cells and less hemoglobin than normal red blood cells. This results in
less oxygen being convenient for use by the cells of the body.
Anyone whose parent has the gene for sickle cell anemia have the chance of at least
having sickle cell trait. In order for a child to have the disease, both parents must
have the sickle cell gene(refer to diagrams 2.1 and 2.2 on page 6). The disease affects
mostly African Americans in Africa, South America, Latin America, the West Indies,
Greece, Spain, Italy, and Turkey.
When the blockage of sickled red blood occurs, it can take place in any organ or
joint of the body wherever a blood clot develops. The frequency and amount of pain varies
widely depending on the person. In some people, painful episodes occur once a year but
for other patients, they can have as many as 15 to 20 episodes annually. These
excruciating, disruptive events can be so brutal that the patient must go into the
hospital for five to seven days to obtain intravenous fluids and narcotic pain killers.
The pain can only be controlled, it cannot be stopped or you cant even identify when it
is likely to happen again.
Sickle cell clots are life threatening, depending on where it occurs. One of the most
severe places for a clot to occur in is the brain. It could lead to a stroke which could
turn into paralysis or even worse, death. Sometimes a blood transfusion is required
every three to four weeks to avoid recurrence of clots in the brain.
When blood capillaries are clogged, it can lead to many types of problems, depending
upon
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where the blockage occurs. The outcome of the blockages may lead to problems such as
kidney infections, death and decay of tissues, intense pain in chest, arms and legs,
disease of the retina of the eye, slow healing sores or ulcers, and even gallstones. When
the hemoglobin is low, it is manifested by fatigue and weakness.
Currently, there is no cure for Sickle Cell Anemia. But the doctors do offer a
treatment that helps control this disease. Pain medication, antibiotics, rest and high
fluid intakes are all treatments for aspects of sickle cell anemia. There are also
experimental therapies that are available to some patients. The drug hydroxyurea is a
treatment that reduced 50% the frequency of painful episodes and hospital visits.
Preventive administration of penicillin to affected children by the age of four months
greatly decreases mortality from infections.
While researching this topic and studying about the disease, I have learned many new
details about it. I realized that even the slightest change in the sequence of amino
acids can lead to very harmful effects. In this disease, only one amino acid was
substituted and still the illness is very harsh. I also learned how exactly the cells
deform and why they go into a sickle shape. It was very interesting to learn that the
disease mostly effects African Americans. I also learned that when the sickles get
clogged in an artery, it results in a very painful attack on the person and may cause
them to have an episode. When episodes occur, the patient may have to go into a hospital
for pain killers. The disease also can lead to ulcers, strokes, paralysis, decay of
tissues, and many other problems throughout the persons entire life. Sickle Cell Anemia
is a very serious disease that effects a person and there way of life. It doesn't have a
known cure yet but many treatments and therapy are available. If a perso
n has this disease, it is life-threatening and painful attacks can
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occur at any time, anywhere. It is important to know the causes and reasons for the
disease so that you can relate to what a person with Sickle Cell Anemia is going
through.
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