Types of Sickle Cell Disease
There are several types of sickle cell disease. The most common are: Sickle Cell Anemia (SS), Sickle Hemoglobin-C Disease (SC), Sickle Beta-Plus Thalassemia and Sickle Beta-Zero Thalassemia.
- Sickle Cell Anemia (SS): When a child inherits one substitution beta globin genes (the sickle cell gene) from each parents, the child has Sickle Cell Anemia (SS). Populations that have a high frequency of sickle cell anemia are those of African and Indian descents.
- Sickle Hemoglobin- C Disease (SC): Individuals with Sickle Hemoglobin-C Disease (SC) have a slightly different substitution in their beta globin genes that produces both hemoglobin C and hemoglobin S. Sickle Hemoglobin-C disease may cause similar symptoms as sickle cell anemia but less anemia due to a higher blood count level. Populations that have a high frequency of Sickle Hemoglobin-C disease are those of West African, Mediterranean and Middle Eastern descents.
- Sickle Beta-Plus Thalassemia: Individuals with Sickle Beta Thalassemia (SB) disease also contain substitutions in both beta globin genes. The severity of the disease varies according to the amount of normal beta globin produced. When no beta globin is produced, the symptoms are almost identical to sickle cell anemia, with severe cases needing chronic blood transfusions. Populations that have a high frequency of Sickle Beta Thalassemia are those of Mediterranean and Caribbean descents.
- Sickle Hemoglobin-D Disease: Through research, hemoglobin D, which is a different substitution of the beta globin gene, has been found to interact with the sickle hemoglobin gene. Individuals with Sickle Hemoglobin-D disease (SD) have moderately severe anemia and occasional pain episodes. Populations that have a high frequency of Sickle Hemoglobin-D disease are those of Asian and Latin American descents.
- Sickle Hemoglobin-O Disease: Hemoglobin O, another type of substitution in the beta globin gene, also interacts with sickle hemoglobin. Individuals with Sickle Hemoglobin- O disease (SO) can have symptoms of sickle cell anemia. Populations that have a high frequency of Sickle Hemoglobin-O disease are those of Arabian, North African and Eastern Mediterranean descents.