Medicina: Ematologia: Talassemie e trapianto del midollo osseo
| English |
| thalassemias |
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| Attestation |
3
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| Part of speech |
Noun
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| Grammatical label |
Countable
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| Variant |
Thalassemia, thal
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| Definition |
Mutations in globin genes cause thalassemias. Alpha-thalassemia affects the alpha-globin gene(s). Beta-thalassemia affects one or both of the beta-globin genes. These mutations result in the impaired synthesis of the beta globin protein portion, a component of Hb, thus causing anemia. In beta-thalassemia minor (ie, beta thalassemia trait or heterozygous carrier-type), one of the beta-globin genes is defective. The defect can be a complete absence of the beta-globin protein (ie, beta-zero thalassemia) or a reduced synthesis of the beta-globin protein (ie, beta-plus thalassemia). The genetic defect usually is a missense or nonsense mutation in the beta-globin gene, although occasional defects due to gene deletions of the beta-globin gene and surrounding regions also have been reported. In beta-thalassemia major (ie, homozygous beta thalassemia), the production of beta-globin chains is severely impaired, because both beta-globin genes are mutated. The severe imbalance of globin chain synthesis (alpha >> beta) results in ineffective erythropoiesis and severe microcytic hypochromic anemia (see Image 2). The excess unpaired alpha-globin chains aggregate to form precipitates that damage red cell membranes, resulting in intravascular hemolysis. Premature destruction of erythroid precursors results in intramedullary death and ineffective erythropoiesis. The profound anemia typically is associated with erythroid hyperplasia and extramedullary hematopoiesis.
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| Definition source |
Takeshita, K. (2002). Thalassemia, Beta. E-Medicine. (INTEEN10)
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| Context |
The thalassemias are a diverse group of inherited disorders in which the rate of production of certain hemoglobins is decreased leading to an imbalance of globin chains available for hemoglobin dimer construction. This results in the formation of abnormal amounts of structurally normal (normal amino acid sequence) hemoglobins.
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| Context source |
University of Virginia. Red Cell Disorders – Thalassemia. (INTEEN07)
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| Synonym |
Thalassemic syndromes, thalassemic diseases, microcythemia
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| Subject field |
Haemopoiesis
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| Specific concept |
beta-thalassemias, alpha-thalassemias, delta-beta-thalassemia, Hb Lepore, Hereditary Persistence of Fetal Hemoglobin
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| it |
Talassemie
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| Reliability code |
3
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