Sickle - Cell Disease

Abstract

Sickle cell disease is a common inherited, multisystem, monogenic disorder of red blood cells (erythrocytes) caused due to polymorphic changes in hemoglobin. The most commonly known condition; Sickle cell anemia wherein there aren’t enough healthy RBCs to carry adequate oxygen throughout the body is considered to be a common form if Sickle-cell disease. Other type of Sickle cell disease is Hemoglobin SC disease (HbSC) caused due to inheritance of beta s and beta c alleles. The third type of such disease is HbS thalassemia caused due to beta-thalassemia mutation in the beta-globin gene leading to Sickle hemoglobin (HbS). Polymerization of HbS due to presence of fetal hemoglobin in the erythrocytes that in turn reduces the concentration of HbS which becomes the prominent determinant to check the severity of the disease. Reduced concentrations of HbS also reduce hemolysis that prevents acute vaso- occlusion. This pain is caused as the irregular shaped RBCs and WBCs get entrapped in the small blood vessels causing vascular obstruction and tissue ischemia. HbS polymerization can also lead to hemolytic anemia which is a state where in rate of RBC destruction is faster than formation; such patients are likely to develop vasculopathy. During the process of hemolysis, hemoglobin is released into plasma that inhibits endothelial nitric oxide signaling causing endothelial cell dysfunction. Hemolysis is also associated with formation of erythrocyte microvesicles that acts as a activator of tissue factor. Malaria is considered to cause HbS. Sickle cell disease is found to be highest in the African continent mostly affecting the new borns. The cause of deaths is hug in Africa due to poor diagnostic facilities. Measures taken against H influenzae and S pneumoniae that is profoundly detected in African children with Sickle cell disease can help reduce the disease proximity. Implementation of early life screening can thereby be effective in this case.