Thalassemia Syndromes

Synonyms

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].

Prevalence

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

Genes

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 affect gene