The normal hemoglobin found in adults is a tetrameric hemeprotein found in red blood cells or erythrocytes. This protein is responsible for oxygen binding into the lungs and oxygen transport to body tissues used for respiration and other metabolic processes. Each hemoglobin tetramer subunit is composed of a heme prosthetic group containing one central coordinately bound iron atom normally in the form of Fe2+, or ferrous, oxidation state. This ferrous iron binds binds with oxygen to be carried where it is required and is responsible for the red coloration of blood.
Common protein components are alpha and beta but it also has gamma and delta subunits (King 2). The Sicke Cell Disease (SCD) is a chronic disease that is punctuated by acute events and that shortens life (Steinberg 1021). When a person inherits two recessive alleles for sickle cell anemia, his phenotypic expression would result to the disease. The SCD is caused by a missense mutation of a single amino acid in the hemoglobin molecule (Ingram 3).
The hemoglobin found in humans with the sickle cell disease differs electrophoretically from the normal hemoglobin. A substitution of Glutamate to Valine occurs in the beta chain, and this results to a shift from a charged amino acid to a neutral one. It becomes hydrophobic and it creates a sticky patch on the molecular surface that causes aggregation upon deoxygenation. These aggregates are hemoglobin S molecule polymers composed of 14-stranded fibers assembled into birefringent domains.
These fiber domains decrease erythrocyte flexibility required for passage through tissue blood vessels. This causes aggregation and clogging Author’s Name 2 resulting to organ damage and symptoms characteristic of the disease (Christoph et al. 1371). There are different symptoms characterizing the SCD. The primary clinical features of this disease are acute episodes of severe pain in the chest, back, abdomen, or extremities that could possibly last for days or weeks.
A frequent complication is the acute chest syndrome which can be fatal to the patient and affects about 40 percent of all people with sickle cell anemia. It usually occurs in children, but its effects are least severe on them. It can occur postoperatively, and when recurrent, chronic respiratory insufficiency may result. Common features of this syndrome are fever, pleuritic chest pain or abdominal pain, cough, lung infiltrates and hypoxia (Steinberg 21).