/thal'euh see"mee euh/, n. Pathol.
a hereditary form of anemia, occurring chiefly in people of Mediterranean origin, marked by the abnormal synthesis of hemoglobin and a consequent shortened life span of red blood cells. Also called Cooley's anemia.
[1932; < Gk thálass(a) sea (alluding to the Mediterranean Sea; the anemia was first reported among children in Mediterranean countries) + -EMIA]

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      group of blood disorders (blood disease) characterized by a deficiency of hemoglobin, the blood protein that transports oxygen to the tissues. Hemoglobin is composed of a porphyrin compound (heme) and globin. Thalassemia is caused by genetically determined abnormalities in the synthesis of one or more of the polypeptide chains of globin. The various forms of the disorder are distinguished by different combinations of three variables: the particular polypeptide chain or chains that are affected; whether the affected chains are synthesized in sharply reduced quantities or not synthesized at all; and whether the disorder is inherited from one parent (heterozygous) or from both parents (homozygous).

      The five different polypeptide chains are: alpha, α; beta, β; gamma, γ; delta, δ; and epsilon, ε. No thalassemic disorder is known to involve the ε-chain. Involvement of the γ-chain or δ-chain is rare. Of the 19 variations of thalassemic inheritance, a few (such as the two heterozygous α-thalassemias) are benign and generally exhibit no clinical symptoms. Other forms exhibit mild anemia, while the most severe form (homozygous α-thalassemia) usually causes premature birth, either stillborn or with death following within a few hours.

      Thalassemia major (homozygous β-thalassemia), also known as Cooley anemia, shows clinical characteristics a few months following birth: anemia, enlarged spleen, and often enlarged liver. Infections commonly develop. At about the age of four years, stunted physical growth becomes apparent. Many patients develop abnormally protruding upper jaws, prominent cheekbones, and marrow expansion in the long bones, ribs, or vertebrae, which fracture easily. Treatment of thalassemia major involves chronic blood transfusions (blood transfusion).

      Thalassemia minor (heterozygous β-thalassemia) is characterized by mild anemia, often presenting no symptoms but occasionally complicated with slight enlargement of the spleen.

      It is thought that the potentially lethal thalassemia gene is retained in the population because it provides some protection from malaria in the heterozygous state. Thalassemia genes are widely distributed in the world but are found most often among people with ancestors from the Mediterranean, the Middle East, and southern Asia. Thalassemia has also been found in some northern Europeans and Native Americans. Among persons of African descent the disease is unusually mild.

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Universalium. 2010.

Look at other dictionaries:

  • Thalassemia — Classification and external resources ICD 10 D56 ICD 9 282.4 …   Wikipedia

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  • thalassemia — from thalasso , comb. form of Gk. thalassa sea + haima blood (see EMIA (Cf. emia)) …   Etymology dictionary

  • thalassemia — [thal΄ə sē′mē ə] n. [ModL < Gr thalassa, sea + EMIA] an inherited chronic anemia, initially found among Mediterranean peoples, resulting from faulty hemoglobin production …   English World dictionary

  • Thalassemia — 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 …   Medical dictionary

  • thalassemia — noun an inherited form of anemia caused by faulty synthesis of hemoglobin • Syn: ↑thalassaemia, ↑Mediterranean anemia, ↑Mediterranean anaemia • Hypernyms: ↑hypochromic anemia, ↑hypochromic anaemia, ↑monogenic disorder, ↑ …   Useful english dictionary

  • thalassemia — noun Etymology: New Latin, from Greek thalassa sea + New Latin emia Date: 1932 any of a group of inherited disorders of hemoglobin synthesis affecting the globin chain that are characterized usually by mild to severe hemolytic anemia, are caused… …   New Collegiate Dictionary

  • thalassemia — Hereditary blood disease in which there is abnormality of the globin portion of haemoglobin. Widespread in Mediterranean countries …   Dictionary of molecular biology

  • thalassemia — noun Any of a group of inherited disorders in which the amount of hemoglobin in the blood is reduced …   Wiktionary

  • thalassemia — n. disease of the blood …   English contemporary dictionary

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