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)

Messenger RNA(mRNA) has been prepared from reticulocytes obtained from patients with different types of thalassaemia and assayed in the wheat germ system. Since normal human reticulocyte mRNA directs the synthesis of equal numbers of alpha- and beta-globin chains in this system it offers a rapid and simple technique for assaying mRNA in the thalassaemic disorders. In mRNA from beta+ thalassaemics the deficiency of beta-globin synthesis mirrored that observed in intact reticulocytes while that prepared from patients wiht haemoglobin H disease gave alpha/beta globin chain production ratios which showed consistently greater imbalance than was found in reticulocytes. Messenger RNA prepared from haemoglobin E-beta0 thalassaemics from Thailand directed no detectable beta-chain synthesis while that prepared from a betaO thalassaemic from Ferrara synthesized a fraction with the chromatographic characteristics of beta-globin chains.
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PMID:Assay of thalassaemic messenger RNA in the wheat germ system. 125 31

There is decreased beta-globin production in beta-thalassemic reticulocytes and nucleated erythroid cells. In this study, we have examined whether unbalanced globin synthesis is expressed at all stages of human erythroid cell maturation. In order to determine the pattern of globin synthesis in early erythroid cells during erythroid cell maturation, an in vitro culture system using human bone marrow erythroid precursor cells has been developed. Early erythroid precursor cells (proerythroblasts and basophilic erythroblasts) have been isolated from nonthalassemic and thalassemic human bone marrows by lysing more mature erythroid cells, using complement and a rabbit antiserum prepared against normal human red cells. In the presence of erythropoietin, differentiation and proliferation of erythroid cells in demonstrable in liquid suspension culture for 24-48 hr, as determined by morphological criteria and by an increase in globin synthesis. The ratio of alpha- to beta-globin chain synthesis in nonthalassemic cells in approximately 1 at all stages of erythroid cell differentiation during culture. In cells from four patients with homozygous beta- thalassemia there is decreased beta-globin synthesis compared to alpha-globin synthesis, both in early erythroid precursor cells and during their maturation in culture. These findings indicate that unbalanced globin chain synthesis is expressed at all stages of red cell maturation in homozygous beta-thalassemia.
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PMID:Isolation and in vitro differentiation of human erythroid precursor cells. 126 Jan 33

With direct sequencing of the amplified cDNA, we analysed the transcript and mRNA splicing defect in a common Chinese beta-thalassemia mutant (IVS-II nt. 654 C-->T). The result shows that this mutant gene would not only produce abnormally processed beta-globin mRNA, but also transcribes a small amount of normally spliced mRNA, hence leading to beta+ thalassemia. The method described herein provides a simple and sensitive approach to the studies of gene expression and molecular defects in genetic diseases at transcriptional level.
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PMID:Study of the RNA splicing defect in the common Chinese beta-thalassemia gene, IVS-II nt. 654 C-->T by using mRNA/PCR. 128 49

Thirty tajiks, whose relatives had beta-thalassemia traits (revealed in previous investigations by determination of the HbA-2 and HbF levels) were selected to screen beta-thalassemia mutations. DNA samples from each individual were subjected to the PCR (polymerase chain reaction) to amplify the 635 bp beta-globin gene fragment. One additional band was detected in three samples after the amplified fragment underwent electrophoresis in 2% agarose gel and the EtBr was stained, and two additional ones were revealed by 6% PAAGE and staining of the EtBr. All additional bands migrated more slowly than appropriate 635 bp fragment. It is supposed that additional bands are heteroduplexes formed from the wild type chains and mutated chains carrying a deletion or insertion. The 4 bp deletion of the 41-42 (-tctt) was detected after the direct sequencing of the amplified fragments. This mutation is common among Chinese but it was not revealed in the Middle Asia populations. The mutation can be easily screened using the PCR and electrophoresis in 2% agarose gel or PAAG of the amplified beta-globin gene fragments.
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PMID:[Molecular nature of beta-thalassemia in Tajikistan: a four base pair deletion in codons 41-42 of the beta-globin gene]. 128 98

The underlying cause of pathology in thalassemia is the premature destruction of red cells, both in the bone marrow and by the reticuloendothelial system. It is generally accepted that the presence of unpaired excess globin chains is the primary circumstance leading to such membrane alterations as oxidation of phospholipids, modification of cytoskeletal proteins and their interactions, reduced membrane-associated ATPase activities, and enhanced permeability of cations. Such perturbations in turn result in the exposure of outer surface neoantigens, enhanced binding of autoantibodies and complement fixation to the outer red cell surface. These factors contribute to the observed distinctive morphologies, increased rigidity and decreased deformability of the thalassemic red cells. In alpha-thalassemic red cells, excess beta-globin chains form homotetramers, Hb H, which are relatively stable and will only damage red cell membrane when precipitated as inclusion bodies, whereas excess alpha-globin chains cannot form such homotetramers and upon synthesis rapidly bind to the cytoplasmic side of the beta-thalassemic red cell membrane, even in young erythroblasts. This difference in properties of the excess globin chains may offer an explanation for the variation in clinical severity observed between these two forms of thalassemia.
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PMID:The thalassemic red cell membrane. 129 98

This study describes a patient with a thalassemia intermedia-like phenotype in whom beta-globin gene sequencing detected a novel abnormal hemoglobin (Hb) due to a T-C substitution at codon 114 of the beta-globin gene arising as a de novo mutation. The abnormal variant was designated Hb Brescia after the place of birth of the propositus. Normal sequences were detected at the in trans beta-globin locus. In addition, alpha-globin gene analysis detected a triple alpha-globin locus which was inherited from the father. The T-C change at position 114 of the beta-globin gene results in a leucine to proline substitution (Leu-Pro) in the G-helix. The resulting Hb tetramer is highly unstable and precipitates forming inclusion bodies in the peripheral red blood cells. Moreover, the Leu-Pro substitution interferes negatively with the four alpha 1 beta 1 contact points of the G-helix most likely adversely affecting the alpha beta dimer formation. The very severe phenotype presented by our patient is unusual in a heterozygote for an unstable Hb variant and may be explained by the coinheritance of the triple alpha-globin locus.
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PMID:A novel beta-globin structural mutant, Hb Brescia (beta 114 Leu-Pro), causing a severe beta-thalassemia intermedia phenotype. 130 Nov 99

Molecular and non-molecular techniques have been utilized for the detection and characterisation of alpha- and beta-thalassaemia genes. Non-molecular techniques example, haematological indices and haemoglobin electrophoresis allow samples to be screened rapidly without the use of radionuclides but these techniques are unable to detect mutations at the gene level. Molecular analysis of alpha- and beta-globin genes either by Southern Blotting and radionuclides or DNA amplification using the polymerase chain reaction (PCR) allows detection of specific mutations and have enabled prenatal diagnosis of the thalassaemias.
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PMID:Detection and molecular analysis of alpha and beta thalassaemia genes--recent developments in screening protocols. 130 68

RFLP haplotypes of 69 chromosomes from members of 18 families affected with beta-thalassemia (beta T) in Guangdong Province were analyzed. 17 haplotypes were found. Haplotypes 1, 2 and 3 accounted for most of them and 4 new haplotypes were identified, three of which were associated with beta T genes. In 9 families, the haplotype data could be used for definitive prenatal diagnosis. In 7 families, 50% exclusive diagnosis could be achieved. In order to know the frequencies of various beta T genes in Guangdong Province and to improve prenatal diagnosis, we identified the beta T genes of 46 affected children in Guangdong Province by amplifying beta-globin gene sequences with the polymerase chain reaction (PCR) and hybridization with allele specific oligonucleotide (ASO) probes. 82 beta T genes hybridized with 6 probes. The most common beta T mutations were frameshift 41/42-TCTT, -28 A----G and IVS-2 nt654 G----T, accounting for 80% of the total. In 36 families PCR combined with hybridization using 6 ASO probes could provide definitive prenatal diagnosis.
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PMID:[Analysis of RFLP haplotypes in the beta-globin gene cluster and the identification of beta-thalassemia genes in patients from Guangdong Province]. 135 May 18

By using oligonucleotide hybridization, restriction endonuclease analysis and direct sequencing of amplified genomic DNA, we have been able to characterize 18 different mutations in the beta-globin genes of 161 beta-thalassemia homozygotes and 107 beta-thalassemia heterozygotes from Turkey (429 beta-thalassemia chromosomes). Previous studies dealing with beta-thalassemia in Mediterranean countries have shown that, in most Mediterranean populations, only a few mutations are prevalent. In contrast, beta-thalassemia in Turkey does not seem to be associated with a few predominant mutations. The six most frequent alleles, IVS-I-110 (G----A), IVS-I-6(T----C), FSC-8 (-AA), IVS-I-1(G----A), -30(T----A) and FSC-5 (-CT), account for only 69.3% of the disease genes; indeed, all 26 mutations assayed represent 85.8% of the disease genes, confirming the considerable molecular heterogeneity of beta-thalassemia among Turks, and indicating the possible presence of rare, previously undefined, mutations in the population. Two mutations observed in this study, IVS-I-116 (T----G) and Cd44(-C), have not been reported in the Turkish population to date. Since preventive medical services, such as genetic counseling and prenatal diagnosis, are greatly improved by detailed knowledge of the molecular pathology of beta-thalassemia, we strongly believe that the presented data will facilitate the intended establishment of a prenatal diagnosis center, based on DNA analysis, in Turkey.
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PMID:The molecular basis of beta-thalassemia in Turkey. 135 Oct 36

We describe in a Japanese family beta zero-thalassemia resulting from a compound heterozygosity for a beta-globin gene mutation. One mutation is a C-to-T transition at IVS-2 nucleotide position 654 on the background of Mediterranean haplotype IX. Another mutation is a G-to-A transition at IVS-2 nucleotide position 1, associated with a novel haplotype XI. The occurrence of these mutations on various chromosomal backgrounds provides strong evidence for an interplay of gene migration, interallelic gene conversion, and multiple origins of the same mutation.
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PMID:Beta-thalassemia major resulting from a compound heterozygosity for the beta-globin gene mutation: further evidence for multiple origin and migration of the thalassemia gene. 135 Oct 38


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