The disorder is caused by a single [[base pair]] change in one of the [[gene]]s that [[codes for]] [[hemoglobin]], the [[blood protein]] that carries oxygen. This abnormality causes hemoglobin to be formed improperly, and causes individual hemoglobin proteins to clump together, impairing the [[binding]] of oxygen. | The disorder is caused by a single [[base pair]] change in one of the [[gene]]s that [[codes for]] [[hemoglobin]], the [[blood protein]] that carries oxygen. This abnormality causes hemoglobin to be formed improperly, and causes individual hemoglobin proteins to clump together, impairing the [[binding]] of oxygen. |