- Not just one disease but rather a complex series of genetic (inherited) disorders all of which involve underproduction of hemoglobin, the indispensable molecule in red blood cells that carries oxygen. The globin part of hemoglobin is made up of 4 polypeptide chains (usually 2 chains of one type and 2 chains of another type of chain). In thalassemia, there is a mutation (change) in one of the types of globin chains. Depending upon which globin chain is affected, the mutation typically leads to underproduction (or absence) of that globin chain, a deficiency of hemoglobin, and anemia.
* * *thal·as·se·mia or Brit thal·as·sae·mia .thal-ə-'sē-mē-ə n any of a group of inherited hypochromic anemias and esp. Cooley's anemia controlled by a series of allelic genes that cause reduction in or failure of synthesis of one of the globin chains making up hemoglobin and that tend to occur esp. in individuals of Mediterranean, African, or southeastern Asian ancestry sometimes used with a prefix (as alpha-, beta-, or delta-) to indicate the hemoglobin chain affected called also Mediterranean anemia see beta-thalassemia
* * *thal·as·se·mia (thal″ə-seґme-ə) [Gr. thalassa sea (because it was observed originally in persons of Mediterranean stock) + -emia] a heterogeneous group of hereditary hemolytic anemias that have in common a decreased rate of synthesis of one or more hemoglobin polypeptide chains and are classified according to the chain involved (α, β, δ); the two major categories are α- and β-thalassemia. Homozygous forms are manifested by profound anemia or death in utero, and heterozygous forms by erythrocyte anomalies ranging from mild to severe.
Medical dictionary. 2011.