Written by Mohammed Majrashi
Blood is a crucial part of the human body’s daily function because of its ability to supply oxygen and nutrients to distant organs and tissue. Blood diseases, however, can hinder this process. When most people think about blood diseases, they instantly recall leukaemia, cancer of the blood, or haemophilia, a condition involving improper blood clotting. However, Sickle Cell Disease, a not-so-mainstream blood disease, is actually a common inherited blood disease that affects about 100,000 Americans [1]. Sickle Cell Disease is primarily found in African-Americans, but is also found in people of Middle Eastern, Indian, Latino, Asian, and Mediterranean descent [1].
Sickle Cell Disease is an autosomal recessive genetic condition. This means that in order to inherit the disease, both parents have to be carriers of the Sickle Cell allele. Moreover, Sickle Cell Disease is a pathophysiology disease that affects multiple systems in the body and causes organ damage that leads to acute illness [2]. Additionally, Sickle Cell Disease results from a mutation in the protein Hemoglobin subunit Beta-globin. This leads to changes in the gene’s seventeenth nucleotide from thymine to adenine and eventually changes the protein sequence from glutamic acid to valine [2]. This mutation causes the haemoglobin subunits to come together and sickle to form Hemoglobin S (Hbs) in a process called polymerization. This produces a hydrophobic (water-fearing) feature that causes the red blood cells to become deoxygenated, dehydrated, and crystallized, disrupting their structure and flexibility [2]. This makes it incredibly difficult for the deformed red blood cells to travel through narrow blood vessels, and may cause a blockage of blood flow that induces a tremendous pain in patients known as Sickle Cell Pain Crisis. As a result, these deformed red blood cells break down rather quickly than normal red blood cells in a process called hemolysis.
Unfortunately, while there is no definitive cure for Sickle Cell Disease, there are two treatment options. One involves blood transfusions, which replenish the body with new and healthy red blood cells that are able to carry oxygen to distant tissues and organs. However, with that comes the risk of developing secondary complications such as Hemochromatosis which is the over-accumulation of iron in various organs from blood transfusions. Another treatment option for Sickle Cell Disease patients is an oral medication called Hydroxyurea. For some people, hydroxyurea has been shown to be promising because of its ability to stimulate the production of fetal haemoglobin and inhibit Hbs polymerization [3].
Sickle Cell Disease is a genetic debilitating condition that affects the conformation of red blood cells. This is important because oxygen cannot be delivered to distant tissues and organs without red blood cells. Currently, there is no cure for Sickle Cell Disease. However, there are treatments that exist and some are more promising than others.
References:
1. “Facts about Sickle Cell Trait and Disease.” North Alabama Sickle Cell Foundation, INC.
2. Rees, David, C., Williams, Thomas, N., Gladwin, Mark, T. 2010. Sickle-Cell Disease. The Lancet. 376: 2018-2031.
3. Rodgers, Griffin, P., Dover, George, J., Uyesaka, Nobuhiro., Noguchi, Constance, T., Schechter, Alan, N., Nienhuis, Arthur, W. Augmentation by Erythropoietin of the Fetal-Hemoglobin Response to Hydroxyurea in Sickle Cell Disease. The New England Journal of Medicine. 378: 73-80.