BIO & 160
Sickle Cell Anemia
Our discussion in class and in our textbook on point mutations was of particular interest to me. Sickle cell anemia is one point mutations that is of interest because it can help us understand how inherited mutations work, and eventually, hopefully, how to cure them. Sickle cell is found in disproportionate numbers in the African and Mediterranean populations. Its discovery and similar ones have also helped in developing the one gene- one polypeptide theory. Sickle cell anemia or as it is sometimes called: sickle- cell disease is more than just a point mutation. It is a heritable blood disorder that affects the shape of red blood cells. The red blood cells of an affected person form an abnormal crescent shape. This allows for less oxygen to be delivered to the body’s tissues because the surface area of the oxygen delivering RBC’s cells is smaller.
Sickled RBC’s can also get stuck more easily in small blood vessels, and break into pieces that interrupt healthy blood flow and may cause tissue damage. Healthy RBC’s are replenished by bone marrow in the body and live about 120 days. In sickle cell, the RBC’s only live 10 to 20 days. The bone marrow cannot make new red blood cells fast enough to replace the dying ones. A person with sickle cell anemia may also experience severe pain, fatigue, bacterial infections, and the possibility of stroke.
Sickle cell is caused by a point mutation in hemoglobin (beta-globin) which results in hemoglobin S. One of the amino acids on the beta-globin chain is not normal. Glutamic acid is replaced by Valine. People with the disease are born with two sickle cell genes, one from each parent. . If you only have one sickle cell gene, it's called sickle cell trait. About 1 in 12 African Americans has sickle cell trait. A blood test can show if you have the...