Sickle cell disease is caused by?

Sickle cell disease is caused by a mutation in the beta-globin gene. This mutation results in the production of a defective form of beta-globin, which is the protein that makes up the oxygen-carrying molecule hemoglobin. The defective beta-globin causes the red blood cells to become sickle-shaped, which can lead to a number of complications, including pain, tissue damage, and organ failure.