It occurs when a person inherits two sickle cell genes or a combination of one sickle cell gene plus any one of several other abnormal hemoglobin genes that affect the red blood cells. Hemoglobin in the red blood cells carries oxygen from the lungs and takes it to every part of the body. A change in the oxygen- carrying hemoglobin inside red blood cells causes the symptoms of sickle cell disease. Red blood cells are normally round and flexible. But when oxygen is released by the red blood cells in people with sickle cell disease, the cells become distorted, forming a rigid banana or sickle shape that can clog blood vessels.
Sickle cells tend to become trapped and destroyed in the liver and in the spleen.
This results in a shortage of red blood cells called anemia which, when severe, can cause the patient to be pale, short of breath and easily tired. Sickle beta thalassemia is a less common form of sickle cell disease. The effects of sickle cell disease vary greatly from one person to the next. Infants and young children with sickle cell disease are especially vulnerable to severe bacterial infections, such as those that cause meningitis and pneumonia. Infections are the leading cause of death in children with sickle cell disease.