Hemoglobin S–Beta-Thalassemia Disease

By Evan M. Braunstein, MD, PhD, Instructor of Medicine, Johns Hopkins School of Medicine

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Anemias Caused by Hemolysis
Overview of Hemolytic Anemia
Autoimmune Hemolytic Anemia
Embden-Meyerhof Pathway Defects
Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency
Hemoglobin C Disease
Hemoglobin E Disease
Hemoglobin S-C Disease
Hemoglobin S–Beta-Thalassemia Disease
Hereditary Spherocytosis and Hereditary Elliptocytosis
Paroxysmal Nocturnal Hemoglobinuria (PNH)
Sickle Cell Disease
Stomatocytosis and Anemia Caused by Hypophosphatemia
Thalassemias
Traumatic Hemolytic Anemia

Hemoglobin S–beta-thalassemia disease is a hemoglobinopathy that causes symptoms similar to those of sickle cell disease, but milder.

Because of the increased frequency of both Hb S (the abnormal hemoglobin that is responsible for sickle cell disease) and beta-thalassemia genes in similar population groups, inheritance of both defects is relatively common. Beta-thalassemia results from decreased production of the beta-polypeptide chains of hemoglobin due to either mutations or deletions in the beta globin gene, leading to impaired production of Hb A (see also Thalassemias).

Clinically, Hb S–beta-thalassemia causes symptoms of moderate anemia and signs of sickle cell disease, which are usually less frequent and less severe than those of sickle cell disease. Mild to moderate microcytic anemia is usually present along with some sickled RBCs on stained blood smears.

Diagnosis requires quantitative hemoglobin studies. The Hb A₂ is > 3%. Hb S predominates on electrophoresis, and Hb A is decreased or absent. Hb F increase is variable.

Treatment, if necessary, is the same as treatment of sickle cell disease.

Last full review/revision January 2017 by Evan M. Braunstein, MD, PhD