Discovering Sicke Cell Anemia


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 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 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