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)

Selective overexpression (50- to 100-fold) in adult erythroid cells of either G gamma or A gamma fetal globin gene is observed in hereditary conditions known as delta beta zero-thalassemia and hereditary persistence of fetal hemoglobin (HPFH). Recently, a C----T change at position -196 of an overexpressed A gamma globin gene from an Italian HPFH was hypothesized, on the basis of indirect evidence, to represent the cause of the functional defect. We now show that the same mutation is present in a different overexpressed A gamma-globin gene from a Sardinian patient with a different syndrome (delta beta zero-thalassemia). The Sardinian A gamma globin gene differs from both the HPFH and the normal A gamma globin gene at nucleotide 1,560 in the noncoding portion of the third exon, where an A is deleted. In addition, the mutant -196 A gamma-globin gene is linked to a normal beta globin gene in HPFH, and to a beta-thalassemic gene (beta 39CAG----TAG) in delta beta zero-thalassemia. These data strengthen the suggestion that -196 mutation is causally linked to the abnormal phenotype and raise the question of whether the same or multiple mutational events are responsible for the appearance of the -196 mutation in different syndromes.
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PMID:Sardinian delta beta zero-thalassemia: a further example of a C to T substitution at position -196 of the A gamma globin gene promoter. 382 30

Thalassemia is a genetic illness which exists every where in the world. In Black Africa, intermediary thalassemia and beta-thalassemia minor are mainly observed. The osteoarthropatic signs are caused by erythroid hyperplasia and overload iron. We mention the roentgenographic skeletal survey of intermediary thalassemia and other less frequent bone abnormalities. We analyse the publications concerning osteoarticular manifestations in beta-thalassemia minor. We report a clinical and anatomical case of intermediary thalassemia with gout complications.
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PMID:[Osteoarticular manifestations of thalassemia]. 382 17

The character and pathogenesis of hemoglobin deficit (gene symbol, hbd), an autosomal recessive trait in the mouse, were studied. The main hematological features of hemoglobin deficit are anemia, red cell hypochromia and microcytosis, and reticulocytosis. The absence of raised fecal urobilinogen excretion and frank hyperbilirubinemia and bilirubinuria suggests that excess hemolysis is not the primary cause of the anemia. The raised plasma iron concentration and the failure of the anemia to respond to parenteral iron treatment indicate that the anemia is not due to iron deficiency. The absence of siderocytes and sideroblasts suggests that anemia is probably not due to ferrochelatase deficiency. Thalassemia is excluded by the finding of balanced reticulocyte globin chain synthesis. The markedly elevated levels of free red cell protoporphyrin taken together with the other findings already noted suggest that the anemia of hemoglobin deficit is due to a defect in the erythroid cell iron procurement mechanisms leading in turn to diminished heme and hemoglobin synthesis.
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PMID:Hemoglobin deficit: an inherited hypochromic anemia in the mouse. 396 Aug 59

A kinetic study of erythroid cell production and destruction (radioactive iron incorporation, red blood cell survival time, bone marrow scintigraphy) was performed in 12 cases of thalassaemia intermedia (six adults and six children), classified retrospectively, and compared to that performed in 17 cases of Cooley's anaemia. Our results confirm the genetic heterogeneity of these cases, the level of Hb F varies from 30% to 100% and the non alpha/alpha chain synthesis is only statistically superior to that seen in Cooley's disease. On the other hand, the kinetic study clearly separates the cases who are, or will be, clinically intermediate, showing a higher radioactive iron medullary uptake, a less ineffective erythropoiesis than that seen in Cooley's disease, and a greater peripheral haemolysis. In our study, no overlap was seen between the two groups. Iron kinetic study is then of prognostic interest and may help in therapy decisions, transfusion regimen and iron chelation, and splenectomy.
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PMID:Red cell kinetics in thalassaemia intermedia: its use for a prospective prognosis. 397 Aug 64

A beta-globin gene cloned from a person with beta-thalassemia contained a T----C substitution within the conserved sequence AATAAA that forms a portion of the recognition signal for endonucleolytic cleavage and polyadenylation of primary mRNA transcripts. By Northern blot analysis a novel beta-globin RNA species, 1500 nucleotides in length, was detected in erythroid RNA. Nuclease protection studies of erythroid RNA, as well as RNA generated upon transient expression of the cloned mutant gene in HeLa cells, located the 3' terminus of this novel, polyadenylated RNA 900 nucleotides downstream of the normal poly(A) addition site, within 15 nucleotides of the first AATAAA in the 3'-flanking region of the beta-globin gene. These findings define the in vivo terminus of an elongated RNA and establish that human beta-globin transcription may extend at least 900 nucleotides 3' of the normal polyadenylation site.
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PMID:Thalassemia due to a mutation in the cleavage-polyadenylation signal of the human beta-globin gene. 401 33

The influence of blood transfusion on erythropoiesis (bone marrow erythroblasts, peripheral blood erythroblasts and reticulocytes) has been studied in 20 non splenectomized homozygous beta thalassaemia patients aged 3 to 16 years and in 10 splenectomized patients aged 8 to 24 years affected with the same disease. The number of reticulocytes was the same in the two groups but the number of erythroblasts in the splenectomized group was higher than in the other group. There was no correlation between the erythroblasts and the reticulocytes of the peripheral blood on one hand and the haemoglobin level proceeding from the same sample on the other hand. In the non splenectomized group of patients, an inverse relationship was found between the percentage of bone marrow erythroblasts and the mean annual haemoglobin level (r = -0.71; p less than 0.01). These results demonstrate the effect of blood transfusion on the erythroid cell line in homozygous beta thalassaemia and the delay between the transfusions and the medullary erythroblastic response.
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PMID:[Effect of blood transfusion on erythropoiesis of homozygotic beta-thalassemia patients]. 408 6

In patients with heterozygous beta-thalassemia, the beta/alpha synthetic ratio in marrow erythroid cells incubated in vitro is 1, whereas in reticulocytes the ratio is 0.5. These ratios reflect the equal synthesis of the two chains on the polyribosomes of the bone marrow and unequal synthesis on the polyribosomes of the peripheral blood reticulocytes. alpha- and beta-chain synthesis is also equal in marrow cells in vivo. Equal synthesis is probably due both to a decrease in alpha-chain synthesis and an increase in beta-chain synthesis in bone marrow erythroid cells and may contribute to the absence of overt hemolysis due to excess alpha-globin chain accumulation in heterozygous beta-thalassemia.
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PMID:Equal synthesis of - and -globin chains in erythroid precursors in heterozygous -thalassemia. 503 31

The decrease in hemoglobin A (HbA, alpha(2)beta(2)) synthesis in the erythroid cells of patients with beta-thalassemia is due to a selective defect in beta-chain synthesis. Since alpha-chains continue to be formed at a normal rate in these cells, this results in a marked relative excess of alpha-chain synthesis over beta- and gamma-chain synthesis. The alpha-chains uncombined with beta- or beta-like-chains (delta, gamma) will be referred to as free alpha-chains. The experiments presented in this paper show that these free alpha-chains are capable of combining with beta-chains to form HbA and are, therefore, structurally normal. Alternatively, in the absence of added beta-chains, alpha-chains aggregates of various sizes are formed. Peripheral blood from patients with beta-thalassemia was incubated with radioactive amino acids and hemolysates were prepared. Column chromatography demonstrates that a majority of the free alpha-chains are not present in HbA. They are strongly bound to carboxymethylcellulose resin at pHs from 7.0 to 10.0, and do not elute with HbA. However, when chemically prepared hemoglobin H (Hbbeta(4)) is added to the fresh hemolysates, the free alpha-chains are readily recovered in the HbA peak. This indicates that the free alpha-chains are able to combine normally with beta-chains to form HbA. Freshly labeled hemolysates were also subjected to Sephadex G-100 chromatography. The free alpha-chains eluted as a broad peak migrating between myoglobin and hemoglobin, consistent with their forming alpha-chain aggregates of various mol wt between 16,000 and 64,000. It is suggested that the chromatographic behavior of the free alpha-chains reported herein simply reflects the chemical properties of normal alpha-chains in the absence of adequate numbers of beta- or gamma-chains. The tendency of these free alpha-chains to aggregate may lead to their intracellular precipitation and the subsequent destruction of the cells containing them.
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PMID:Hemoglobin synthesis in beta-thalassemia: the properties of the free alpha-chains. 564 22

The transferrin iron transport system, along with its procurement sites and delivery receptors, provides a highly effective means of satisfying internal iron requirements. Iron uptake by individual tissues is determined by their receptor number, by the relative amounts of monoferric and diferric transferrin in circulation, and by the amount of available iron in donor tissues. Although the modus operandi of this system under basal conditions has been characterized, its exquisite regulation remains an enigma. In some manner, the procurement of iron is determined by iron requirements. What seems to be an inappropriate behavior of the absorptive mechanism in thalassemia and certain other erythroid overload states may actually be life-saving in the absence of transfusion, since it results in higher levels of plasma iron and thereby higher levels of erythropoiesis. The definition of the regulatory mechanism in such conditions may well lead to an understanding of the molecular defect in idiopathic hemochromatosis.
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PMID:Transferrin: physiologic behavior and clinical implications. 608 33

The suppressive effect of two types of human interferon (fibroblast and leukocyte types) on bone marrow and peripheral blood erythroid colony formation by cells from patients with various disorders of erythropoiesis was studied. Bone marrow or peripheral blood mononuclear cells were isolated and cultured in plasma clots with Epo, and benzidine-positive erythroid colonies counted after 7 to 14 days' incubation. Specimens included cells from patients with thalassemia, sickle cell anemia, secondary polycythemia, nutritional anemia, hemolytic anemia, refractory anemia, and normal controls. Results show that with the exception of nutritional anemia cells, erythroid colony formation by all specimens was significantly inhibited (84% to 100%) by 100 to 200 U of either interferon type per milliliter. Erythroid colony formation by nutritional anemia bone marrow cells ws inhibited only 30% to 40% by 200 U/ml fibroblast or leukocyte interferon, and 100 U/ml were ineffective. Sickle cell peripheral blood mononuclear cells and refractory anemia bone marrow demonstrated marked inhibition of colony formation (86% to 97%) with 50 U/ml fibroblast or leukocyte interferon. Inhibition of colony formation by sickle cell peripheral blood mononuclear cells was completely abolished by addition of anti-interferon. Colony formation by refractory anemia bone marrow was inhibited 46% to 51% by as little as 10 U/ml fibroblast or leukocyte interferon. This concentration of interferon was ineffective with cells from thalassemia, secondary polycythemia, nutritional anemia, hemolytic anemia, and controls. Mouse bone marrow colony formation was not suppressed by 200 U/ml leukocyte interferon. These results demonstrate that fibroblast or leukocyte interferons inhibit in vitro erythroid colony formation by human bone marrow or peripheral blood mononuclear cells, the effect is abolished by anti-interferon, and inhibition may be species-specific. These studies reveal that cells obtained from certan patients are particularly sensitive to the cytoxic effects of interferon, and it may be useful to monitor the erythropoietic state of the patient during interferon chemotherapy.
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PMID:Suppressive effect of human interferons on erythroid colony growth in disorders of erythropoiesis. 615 73


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