Deltabetathalassemia

Deltabetathalassemia, also known as delta-beta thalassemia, is a hereditary blood disorder caused by deletions or complex rearrangements that remove both the delta (HBD) and beta (HBB) globin gene clusters on chromosome 11. The loss of these beta-like globin genes leads to reduced production of hemoglobin A (HbA) and hemoglobin A2 (HbA2), with a compensatory increase in fetal hemoglobin (HbF, gamma chains). The resulting imbalance of globin chain synthesis produces varying degrees of anemia.

Clinical features form a spectrum. Individuals with a delta-beta-thalassemia trait (heterozygotes) typically have mild microcytic, hypochromic anemia and may be asymptomatic. In homozygous or compound states, the condition can resemble beta-thalassemia intermedia or, less commonly, beta-thalassemia major, with a broader range of anemia severity. High levels of HbF often ameliorate symptoms, but clinical presentation remains highly variable depending on the exact genetic deletions and HbF response.

Diagnosis relies on blood tests and molecular analysis. Hematologic studies show microcytosis with low or absent HbA and HbA2 and elevated HbF. Hemoglobin electrophoresis or high-performance liquid chromatography quantifies these fractions, and genetic testing confirms deletions in the beta-globin gene cluster. Differential diagnosis includes other beta-thalassemias and HPFH (hereditary persistence of fetal hemoglobin).

Management is tailored to severity. Mild cases may require little to no treatment, with focus on routine monitoring and oral iron supplementation if iron deficiency is present. More significant anemia may necessitate regular transfusions and iron chelation therapy. Genetic counseling is important, particularly for family planning, given the autosomal recessive inheritance pattern.