Sickle cell disorders

Some people inherit one sickle cell gene and one defective hemoglobin gene of another type, resulting in various types of sickling disorders. These disorders range from mild to severe.

• Sickle cell disease (hemoglobin SS disease) occurs when both genes produce hemoglobin S. This person typically has symptoms of anemia, mild to life-threatening complications, and a shortened life span.
• Sickle beta-thalassemia occurs when a person has one hemoglobin S gene and another gene that causes the body to produce less hemoglobin than normal. This person may have mild to severe sickle cell disease.
• Hemoglobin SC disease occurs when a person has one hemoglobin S gene and one abnormal hemoglobin C gene. This person may have generally milder symptoms and a longer life span than a person with sickle cell disease but may become seriously ill nonetheless.
• Hemoglobin SO disease and hemoglobin SD disease occur when a person has one hemoglobin S gene and one abnormal hemoglobin O or hemoglobin D gene. This person may experience all sickle cell disease symptoms, ranging from mild to severe.