The Relation of Vitamin D Deficiency to Vaso Occlusive Crisis in Patients with Sickle Cell Disease

Abstract

Sickle cell disease (SCD) is a genetic disorder caused by the substitution of the amino acid Valine in place of glutamate at position 6 of the hemoglobin chain, which results in significant hemoglobin instability, solubility and morphological changes -in the form of misshapen red blood cells that are incapable of normal oxygen exchange-. SCD is prevalent among people of black African descent and regions where malaria is endemic (e.g., Africa, the Middle East, the eastern Mediterranean region and India). The heterozygous form is associated with increased malaria resistance (heterozygous advantage). The clinical hallmark of SCA is the painful acute ‘‘crisis’’ that continues to be a treatment challenge despite therapeutic advances. SCD crises occur with variable frequency and duration and they often require hospitalization. SCD crises are characterized by HbS polymerization, episodic vascular occlusion induced by sickled RBCs. Pain is thought to follow bone marrow vasculature infarction, leading to the release of inflammatory mediators that stimulates afferent nerve fibers. Vaso-occlusion also follows adherence of