Sickle cell disease is a blood disease. Instead of red blood cells containing normal hemoglobin, they contain sickle hemoglobin.
Sickle hemoglobin makes red blood cells stiff and sticky.
This leads to anemia and blockage of blood vessels. More African Americans suffer from this disease than any other race. Sickle cell disease is inherited. In other words, you are born with it. You cannot outgrow sickle cell disease.