Medicina: Ematologia: Talassemie e trapianto del midollo osseo
| English |
| beta-thalassemias |
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| Attestation |
3
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| Part of speech |
Noun syntagm
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| Grammatical label |
Countable
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| Variant |
b-thalassemia, b thalassemia, beta thalassemia, b -thal
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| Definition |
There are hundreds of mutations within the beta globin gene, but approximately 20 different alleles comprise 80% of the mutations found world wide. Within each geographic population there are unique mutations. Individuals who have beta-thalassemia major are usually homozygous for one of the common mutations, or heterozygous for one of the common mutations and one of the geographically-unique mutations. Both lead to absence of beta globin chain production. The beta-thalassemia syndromes are much more diverse than the alpha-thalassemia syndromes due to the diversity of the mutations that produce the defects in the beta globin gene. Unlike the deletions that constitute most of the alpha-thalassemia syndromes, beta-thalassemias are caused by mutations on chromosome 11 that affect all aspects of beta globin production: transcription, translation, and the stability of the beta globin product. Most hematologists feel there are three general categories of beta-thalassemia: beta-thalassemia trait, beta-thalassemia intermedia and beta-thalassemia major. Splice site mutations also occur and are of clinical consequence, when combined with a thalassemia mutation. Three splice site mutations occur in exon 1 of the beta globin gene. These mutations result in three different abnormal hemoglobins: Malay, E, and Knossos. Hemoglobin E is a very common abnormal hemoglobin in the Southeast Asian population, and when paired with a b0 thalassemia mutation, can produce severe transfusion-dependent (Eb0) thalassemia.
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| Definition source |
Children’s Hospital Oakland. Medical Management. Definition of Thalassemia.
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| Context |
b-Thalassemia is a highly heterogeneous group of inherited disorders of b globin gene expression. More than 140 different b globin gene mutations have been identified in the world population. There is a high frequency of this disorder among people living in regions where malaria is or has been endemic.
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| Context source |
Kotea, N., et al. (2000). ‘Spectrum of beta thalassemia mutations and their linkage to beta-globin gene haplotypes in the Indo-Mauritians’. American Journal of Hematology 63(1):11-5. (RISCEN169)
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| Synonym |
beta-microcythemia
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| Subject field |
Haemopoiesis
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| Sub-field (level 1) |
Thalassemias
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| Generic concept |
Thalassemias, microcythemias
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| Specific concept |
b+-thalassemia, b0-thalassemia, beta-thalassemia major, beta-thalassemia intermedia, beta-thalassemia minor
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| Coordinate concept |
Alpha-thalassemias
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| it |
Beta-talassemie
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| Reliability code |
3
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