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Query: UMLS:C0039730 (thalassemia)
 10,305 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The early identification of some clinically significant hemoglobinopathies and the precise differentiation of hemoglobin variants are important to provide early comprehensive medical care to prevent some serious complications, assess prognosis, and offer genetic counseling. Laboratory approaches to screen for and confirm inherited hemoglobinopathies in children are presented. Methods include routine screening procedures as well as techniques available in research laboratories, with emphasis on readily available procedures. Since microcytic hypochromic anemia is the most common type of anemia in children under two years, attention is given to the differentiation of thalassemia trait from iron deficiency. The step-by-step work-up is also described for differentiating beta-thalassemia from alpha-thalassemia.
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PMID:Laboratory identification of inherited hemoglobinopathies in children. 616 96

The author was a biochemist who, because he had experience in plasma iron estimations, became involved in the investigation of a hypochromic anemia in India during World War II. This led to another such study in Uganda after the war. There, an investigation of the incidence of sickling led to the discovery of overall differences between Hamitic-speaking tribes and the Bantu and Nilotes. A few exceptions could later be explained on the basis of the effect of malaria on sickling incidence. A mapping of the world distribution of sickle-cell and other hemoglobins followed, as well as a search for factors which cause the severity of sickle-cell anemia to vary. A most important lowering influence on this severity seems to be that of alpha-thalassemia. It is suggested that the high incidence of alpha-thalassemia type 2 (alpha/alpha alpha) in malarial regions is not related to malaria itself but to the beta-chain abnormalities which protect against malaria and therefore are frequent in the same populations. Alpha thalassemia in turn has a selective value because it lowers the pathological effect of sickle-cell anemia, as well as the consequences of Hemoglobin E and beta-thalassemia.
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PMID:Sickle cell anemia 35 years ago: reminiscence of early African studies. 637 13

Ferritin, iron, total iron binding capacity and transferrin saturation were measured in the serum of 247 patients with microcytic hypochromic anemia. Differentiation into various categories of microcytic hypochromic anemia was based on clinical criteria and on the response to iron treatment. This produced 147 patients with iron deficiency anemia, 35 patients with anemia secondary to infection, 27 patients with anemia due to tumor and 38 patients with thalassemia. Analysis of the iron parameters revealed the reliability of both serum ferritin and transferrin saturation in distinguishing between the various forms of anemia. However, measurement of serum ferritin is slightly more reliable and much less expensive than determination of transferrin saturation.
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PMID:[The value of serum ferritin, serum iron and iron-binding capacity in the differential diagnosis of microcytic hypochromic anemia]. 705 13

Three subjects in a family with microcytic and hypochromic anemia were studied; red blood cell morphology indicated aniso-poikilocytosis and hypochromasia. Target and tear-drop cells were also noted. In all three cases evaluated, there was an increase in HbA2 levels and a decline in the beta/alpha synthesis ratio. Direct cloning and DNA sequencing identified a point mutation (G-->T) at position 1 of intervening sequence I. The resulting reduction of beta-globin chain synthesis is considered to give rise to beta 0-thalassemia phenotype. This point mutation is to our knowledge, the first case in Japan.
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PMID:Beta 0-thalassemia trait (IVS-I-1 G-->T) in a Japanese family. 801 89

The beta-thalassemia syndromes are a heterogeneous group of genetic disorders characterized by reduced or absent expression of the beta-globin gene. To date, over 300 beta-thalassemia alleles have been characterized in or around the beta-globin region. Thalassemia major is severe anemia necessitating chronic blood transfusions, splenectomy, iron chelation therapy, and bone marrow transplantation. Usually thalassemia major results from homozygosity or compound heterozygosity for severe betaO- and/or beta+-thalassemia mutations. Thalassemia intermedia is a clinical diagnosis that describes a symptomatic but less severe condition than beta-thalassemia major. beta-thalassemia intermedia may arise from several different combinations of alpha- and/or beta-thalassemia mutations. Heterozygous beta-thalassemia is typically characterized by a mild microcytic hypochromic anemia without any significant clinical implications. In this report, we describe a 63-year-old Africian American woman with asymptomatic homozygous beta-thalassemia, who seems to carry 2 copies of the -29 mutation in the promoter region of the beta-globin gene. Her elevated hemoglobin F level of 83% was associated with heterozygosity for the Xmn I polymorphism upstream of the Ggamma-globin gene. Southern blot analysis at the alpha-globin locus did not show any deletion that would account for the mildness of her phenotype. Therefore, homozygosity for the -29 mutation along with the Xmn I polymorphism appears to confer an extremely mild beta-thalassemia phenotype. This observation has important implications in the prenatal diagnosis and genetic counseling of families segregating this type of genetic defect.
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PMID:Molecular basis of asymptomatic beta-thalassemia major in an African American individual. 905 61

Monogenic diseases are very unevenly distributed throughout the world and beta-thalassemies are due chiefly to a large number of point mutations of the beta globine gene. The thalassemia trait (heterozygous thalassemia) can be asymptomatic and diagnosis is established by demonstration of an increased proportion of Hb A2. In the homozygous state (thalassemia major) hypochromic anemia is extremely severe because erythropoiesis is largely ineffective. Regular transfusion is necessary to prevent early death and transfusion therapy is usually initiated in the first year of life after biological diagnosis. Iron chelation is now capable of preventing transfusional haemachromatosis responsible for late mortality. 10% only of patients with homozygous beta-thalassemia have a syndrome of intermediate haematologic severity (thalassemia intermedia). Hb S--beta-thalassemia disease is characterised by a clinical course that resembles more that of Sickle Cell disease than to the thalassemia syndromes.
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PMID:[Beta-thalassemia: clinical manifestations]. 1147 35

We report a 43-year-old Japanese woman with microcytic and hypochromic anemia, who had been erroneously diagnosed as having iron deficiency anemia 20 years previously at the time of her first labor, and treated with iron and blood transfusion. At the present visit to our clinic, she was found to have an increased HbA2 level and prolonged glycerol lysis time. Genetic analysis of the beta-globin gene revealed deletion of 3 bases at codons 127/128 (CAG/GCT-->CCT). A genetic study of the patient's family showed that two of her four children possessed the same mutation. The patient had mild anemia, her first son had very mild anemia, and her second daughter had moderate anemia with hemolysis. These affected family members were diagnosed as having dominant-phenotype beta-thalassemia.
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PMID:[A family with dominant-phenotype Beta-thalassemia]. 1197 52

Beta-Thalassemia is uncommon in the Korean population, however, it must be considered in the differential diagnosis of hypochromic anemia. The molecular characterization of beta-thalassemia is absolutely necessary for molecular diagnosis as well as any genetic epidemiological study in this region. We analyzed the molecular basis of beta-thalassemia in 38 Korean families. Using direct sequencing of genomic DNA amplified through polymerase chain reaction and haplotype analysis, 35 beta-thalassemic genes were characterized, all of which were heterozygous. Twelve different mutations were identified. The most common mutations noted included the initiation codon ATG-->AGG (beta0) (28.9%), codon 17 (beta0) (A-->T) (18.4%), and IVS-II-1 (beta0) (G-->A) (10.5%). Interestingly, mutations causing dominantly inherited beta-thalassemia were also common (15.7%). All four cases with the IVS-II-1 (G-->A) mutation were linked to the silent mutation of codon 91 (C-->T) of the beta-globin gene. The initiation codon A7G-->AGG and IVS-II-1 (G-->A) with codon 91 (C-->T) mutations were found in the Far East only, and may be inherited from a common origin for each mutation, at least in Koreans. The codon 17 (A-->T) and codons 41/42 (beta0) (-TTCT) were suggested to be introduced by gene-flow from southern China. Otherwise, only Hb Korea [codons 33/34 (beta0) (-GTG)] and a novel beta-thalassemic mutation, codons 89/90 (beta0) (-GT), were identified in Koreans. This mutation spectrum is characteristic of the low prevalence area of beta-thalassemia in Korea, it is, however, quite different from the adjacent countries, Japan and China.
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PMID:Beta-thalassemia in the Korean population. 1214 56

Beta-thalassemia is uncommon in the Korean population, however it must be considered in the differential diagnosis of hypochromic anemia. The molecular characterization of beta-thalassemia is absolutely necessary for molecular diagnosis as well as any genetic epidemiological study in this region. We analyzed the molecular basis of beta-thalassemia in 47 Korean families. Using direct sequencing of genomic DNA amplified through PCR and haplotype analysis, 44 beta-thalassemia genes were characterized, all of which were heterozygous. Fourteen different mutations were identified. The common mutations noted included the initiation codon (CD) ATG-->AGG (23.4%), CD 17 A-->T (21.2%), and IVS-II-1 G-->A (12.7%). Interestingly, mutations causing dominantly inherited beta-thalassemia were common (17.0%). All cases of IVS-II-1 G-->A mutations were linked to the silent mutation of CD 91 C-->T of the -globin gene. The initiation CD ATG-->AGG and IVS-II-1 G-->A with CD 91 C-->T were found in the Far East only, and may be inherited from a common origin for each mutation, at least in Koreans. CD17 A-->T and CDs 41/42-TTCT were suggested to be introduced by gene-flow from southern China. Otherwise, Hb Korea, CDs 89/90 -GT and a novel beta-thalassemia mutation, CD 131 CAG-->TAG, were only identified in Koreans. This mutation spectrum is characteristic of the low prevalent area of beta-thalassemia, however it is quite different even from the adjacent countries, Japan or China.
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PMID:Beta-thalassemia in the Korean population. 1243 Sep 7

We report a case in which the interaction of heterozygosis for both the 0-IVS-II-1 (G->A) mutation and the alpha alpha alpha anti-3,7 allele was the probable cause for the clinical occurrence of thalassemia intermedia. The propositus, a 6-year-old Caucasian Brazilian boy of Portuguese descent, showed a moderately severe chronic anemia in spite of having the -thalassemia trait. Investigation of the alpha-globin gene status revealed heterozygosis for alpha-gene triplication (alpha alpha alpha / alpha alpha). The patient's father, also presenting mild microcytic and hypochromic anemia, had the same alpha and genotypes as his son, while the mother, not related to the father and hematologically normal, was also a carrier of the alpha alpha alpha anti-3,7 allele. The present case emphasizes the need for considering the possibility of alpha-gene triplication in -thalassemia heterozygotes who display an unexpected severe phenotype. The -thalassemia mutation found here is being described for the first time in Brazil.
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PMID:Thalassemia intermedia as a result of heterozygosis for beta 0 -thalassemia and alpha alpha alpha anti-3,7 genotype in a Brazilian patient. 1279 97


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