Sickle cell disease is a group of inherited blood disorders caused by the presence of hemoglobin S in red blood
cells. The red cells change to a sickle (banana) shape and can clog blood vessels causing damage to the body's tissues and organs.

Sickle cell anemia (Hb SS) is the most common type of sickle cell disease. There are other hemoglobin types such as hemoglobin C or hemoglobin E, that in combination with the gene for sickle hemoglobin can result in different forms of sickle cell disease (Hb SC, Hb SE, Hb S/beta thalassemia).