Dr. S.0 MIKAYEDr. S.0 MIKAYE

Sickle Cell Disease 

Definition

* An inherited autosomal recessive disorder caused by the presence of hemoglobin S (HbS).
* Red blood cells become sickle-shaped under low oxygen conditions, leading to hemolysis and vaso-occlusion.

Genetics

* Mutation in the β-globin gene.
* Homozygous HbSS causes sickle cell disease.
* Heterozygous HbAS is sickle cell trait.

Pathophysiology

* HbS polymerizes during deoxygenation.
* RBCs become rigid and sickle-shaped.
* Causes:
* Chronic hemolytic anemia
* Vaso-occlusion
* Tissue ischemia and organ damage