Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The presence of several polymorphic markers along the alpha-globin gene complex allows the identification of haplotypes associated with alpha-thalassemia determinants. These are found at very high frequencies in geographic areas where malaria is or has been endemic which suggests a positive selective role by the parasitic disease in favour of alpha(+)-thalassemia mutants. A population survey among forest tribal communities from Andhra Pradesh, India, revealed the prevalence and molecular heterogeneity of alpha(+)-thalassemia determinants presumably due to a long backdated malaria endemicity among these populations. Analysis of the tribal alpha-thalassemia haplotypes has shown a great degree of genetic heterogeneity which can be explained as the result of multiple recombination events in the presence of natural selection by malaria.
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PMID:Multiple recombination events are responsible for the heterogeneity of alpha(+)-thalassemia haplotypes among the forest tribes of Andhra Pradesh, India. 204 35

Hypochromic anaemia is very common among the island populations of Vanuatu in the South-West Pacific. Results of a large-scale survey show that, unexpectedly, this form of anaemia is seldom due to iron deficiency or coexistent parasitic disease. Rather, it results from a previously unsuspected high incidence of alpha-thalassaemia which has been identified only by application of DNA analysis to the populations studied. These findings suggest that hypochromic anaemia in tropical or subtropical populations should not necessarily be attributed to iron deficiency; detailed studies of iron status should be carried out before major dietary changes or fortification of food with iron are implemented.
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PMID:Relative roles of genetic factors, dietary deficiency, and infection in anaemia in Vanuatu, South-West Pacific. 286 13

The frequency of alpha+-thalassaemia, but not other unlinked DNA polymorphisms, exhibits an altitude- and latitude-dependent correlation with malaria endemicity throughout Melanesia, supporting the hypothesis that protection against this parasitic disease is the major factor responsible for the high frequencies of haemoglobinopathies in many parts of the world.
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PMID:High frequencies of alpha-thalassaemia are the result of natural selection by malaria. 371 63

Malaria, caused by members of the genus Plasmodia, is still the most prevalent parasitic disease in the world. In an attempt to understand genetic factors conferring resistance to malaria, mouse models of thalassemia, sickle trait, and ankyrin and spectrin deficiency were studied during infection with species of malaria infectious to rodents. Although growth of P. falciparum is not inhibited in thalassemic erythrocytes in culture, mice carrying a beta-thalassemia mutation were protected from Plasmodium chabaudi adami, supporting epidemiologic findings. Transgenic mice expressing beta s hemoglobin were also significantly protected from two species of rodent malaria. Importantly, a significant role for the spleen in protection in the beta s transgenic mice was found. Finally, mice deficient in spectrin and ankyrin were studied with respect to their ability to support the growth of malaria. It was found that spectrin deficient mice were almost completely refractory to P. chabaudi adami and P. berghei. These models will allow further study of host factors in resistance to malaria.
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PMID:Transgenic and mutant animal models to study mechanisms of protection of red cell genetic defects against malaria. 842 8

The frequency and etiology of anemia were investigated in 2,913 children between six and 16 years of age in Sanliurfa, in the southeast region of Turkey. Anemia was found in 142 (7.8%) children in the 6-11 years of age group, and in 16 (1.5%) in the 12-16 years of age group; in total, in 158 (5.4%) children. Causes were iron deficiency in 93 (58.9%) children, beta-thalassemia heterozygosity in 10 (6.3%) children, chronic disease that causes anemia of inflammation in 30 (19.0%) children, and intestinal parasitic infections in 17 (10.8%) children. In eight (5.1%) children, the cause of anemia could not be determined. The study's results showed that iron deficiency anemia and chronic and parasitic disease are important problems in schoolchildren of Sanliurfa, while beta-thalassemia and hemoglobinopathies have less importance.
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PMID:The frequency and etiology of anemia among children 6-16 years of age in the southeast region of Turkey. 1093 71