Beta-thalassemia intermedia

Beta-thalassemia intermedia (also known as non-transfusion-dependent thalassemia or thalassemia intermedia) is a hereditary hemoglobin disorder caused by mutations in the HBB gene, which encodes the beta-globin chain of hemoglobin. It represents a clinical phenotype of intermediate severity between the mild beta-thalassemia trait (carrier state) and the severe transfusion-dependent beta-thalassemia major. The condition results from reduced production of beta-globin chains, leading to an imbalance between alpha- and beta-globin chains, ineffective erythropoiesis, chronic hemolytic anemia, and compensatory expansion of the bone marrow. Patients with beta-thalassemia intermedia typically present in childhood or later, usually after the age of two years, with moderate anemia (hemoglobin levels generally between 7–10 g/dL). Key clinical features include pallor, fatigue, jaundice, hepatosplenomegaly (enlargement of the liver and spleen), skeletal deformities due to bone marrow expansion (particularly facial bone changes and osteoporosis), gallstones, leg ulcers, and an increased risk of thromboembolic events. Iron overload is a significant complication that can develop even without regular transfusions, due to increased intestinal iron absorption driven by ineffective erythropoiesis. Over time, iron overload can damage the heart, liver, and endocrine organs. Management of beta-thalassemia intermedia is individualized based on clinical severity. Many patients do not require regular blood transfusions but may need occasional transfusions during periods of physiological stress, infection, or pregnancy. Iron chelation therapy is often necessary to manage iron overload. Folic acid supplementation is commonly recommended. Splenectomy may be considered in cases of significant splenomegaly or worsening anemia. Hydroxyurea and other fetal hemoglobin inducers may be used to increase hemoglobin F levels and improve anemia in some patients. Luspatercept, a recombinant fusion protein that promotes late-stage erythropoiesis, has been approved for treatment of anemia in non-transfusion-dependent beta-thalassemia. Hematopoietic stem cell transplantation remains the only curative option, and gene therapy approaches are under active investigation.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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