 Sickle cell disease SCD, specifically hemoglobin SC disease HbSC, is a subtype of sickle cell disease with typically higher hemoglobin and milder or later disease complications. Sickle cell disease is a disorder in which red blood cells RBCs are abnormally shaped. This can result in painful episodes, serious infections, and damage to body organs. One medication used to treat sickle cell disease is hydroxyurea. 