Beta-thalassemia associated with another hemoglobin anomaly

Beta-thalassemia associated with another hemoglobin anomaly (Orphanet code 231230) is a group of rare hemoglobin disorders in which an individual inherits a beta-thalassemia mutation on one allele of the HBB gene along with a different structural hemoglobin variant on the other allele. This category encompasses several compound heterozygous conditions, including but not limited to beta-thalassemia/hemoglobin E disease, beta-thalassemia/hemoglobin C disease, beta-thalassemia/hemoglobin D disease, and beta-thalassemia/hemoglobin O-Arab disease, among others. The clinical severity varies widely depending on the specific combination of mutations, ranging from a mild, clinically silent carrier state to a severe transfusion-dependent anemia resembling thalassemia major. These conditions primarily affect the hematologic system. Defective or reduced beta-globin chain production leads to ineffective erythropoiesis, chronic hemolytic anemia, and compensatory expansion of the bone marrow. Key clinical features may include pallor, fatigue, jaundice, splenomegaly, hepatomegaly, growth retardation in children, skeletal deformities due to bone marrow expansion, and iron overload — either from the disease process itself or as a consequence of repeated blood transfusions. In more severe forms, complications such as cardiac dysfunction, endocrine abnormalities, and liver disease can develop due to progressive iron accumulation in organs. Treatment depends on the clinical severity of the specific compound heterozygous state. Mild forms may require only monitoring and folic acid supplementation. Moderate to severe forms may necessitate regular red blood cell transfusions combined with iron chelation therapy to prevent iron overload. Hydroxyurea may be beneficial in some subtypes, particularly beta-thalassemia/Hb E disease, by increasing fetal hemoglobin production. Hematopoietic stem cell transplantation remains the only curative option for severe cases. Gene therapy approaches are under investigation. Patients require lifelong multidisciplinary follow-up including hematology, cardiology, and endocrinology care.

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