Reference Work Entry

Encyclopedia of Molecular Mechanisms of Disease

pp 2041-2042

Thalassemia Syndromes

  • John-John B. SchnogAffiliated withDepartment of Internal Medicine, Slotervaart Hospital
  • , Victor E. A. GerdesAffiliated withAmsterdam Vascular Medicine Group, Department of Vascular Medicine, Academic Medical Center


Cooley’s anemia (synonymous for β-thalassemia major); Hb Bart’s hydrops fetalis (synonymous for alpha 0 thalassemia homozygosity)

Definition and Characteristics

Recessive hereditary disorders caused by a deficiency in hemoglobin polypeptide chain synthesis. The diseases are characterized by variable degrees of hemolytic anemia with ineffective erythropoiesis and secondary hemochromatosis, splenomegaly, and bony deformations due to extramedullary hematopoiesis. Most patients with thalassemia major die from complications of iron overload [1,2].


Most common genetic disorder worldwide, with high frequencies in the Mediterranean, the Middle East, South-East Asia, India, Burma and Africa [1].


Four α genes (αα/αα; 16ptr-p13.3) encode for α globin chain synthesis and two β genes (11p15.5) encode β globin chain synthesis. Most mutations leading to α thalassemia are gene deletions, whereas in β thalassemia, most mutations af ...

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