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 gene frequency for (--SEA/) deletional alpha-thalassaemia is high in Southeast Asian populations. We report a simple immunocytological test that is highly sensitive and specific for the detection of adult carriers of the (--SEA/) deletion. We prospectively studied 206 consecutive adult blood samples. All 41 with the (--SEA/) deletion had a positive test; all but 1 of the 165 non-carriers were negative. This test, whose major requirement is a fluorescence microscope, should be useful to identify couples at risk of conceiving fetuses with homozygous alpha-thalassaemia.
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PMID:Immunocytological test to detect adult carriers of (--SEA/) deletional alpha-thalassaemia. 790 77

We sequenced part of the X boxes of alpha-thalassemia-1 of Southeast Asia type (- -SEA) with -alpha 4.2, -alpha 3.7, -alpha G-Taichung, and alpha CS alpha. We found the X box of -alpha 3.7 belonged to the X box of alpha 2 globin gene and the X box of alpha CS alpha contained X boxes of both alpha 1 and alpha 2 globin gene, whereas the X box of -alpha 4.2 and -alpha G-Taichung was a hybrid of X boxes of alpha 2 and alpha 1 globin gene. We also found there are two types of -alpha 4.2 deletion; type 1 is a common type of -alpha 4.2 deletion and type 2 is linkage to -alpha G-Taichung. We used a combination of two methods, the amplification refractory mutation system (ARMS) and the amplified created restriction sites (ACRS), to amplify the hybrids of X boxes specifically. The upstream primer for X box of alpha 2 globin gene was designed following the standard ARMS procedure to amplify the X segment of the alpha-globin gene. The downstream primer was designed according to the ACRS method to check the specificity of PCR products. Using this approach, we can diagnose the different types of -alpha 4.2 deletion. This kind of approach can also be used to amplify the specific region from the cluster of highly homologous genes.
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PMID:Rapid detection of -alpha 4.2 deletion of alpha-thalassemia-2 by polymerase chain reaction. 794 8

For the genetic counselling, 8,432 blood samples from Chinese couples were screened for detecting alpha-thalassemia in Guangzhou city. The positive diagnosis of 646 (7.66%) alpha-thalassemia patients was made. One hundred DNA random samples from the above positive cases were collected and were analysed by using polymerase chain reaction (PCR) to determine the genotype of alpha-thalassemia of Southeast Asian deletion(--SEA/). Of 100 alpha-thalassemia individuals screened for the (--SEA/) mutation, 99 (96 with alpha-thalassemia trait and 3 with hemoglobin H disease) were detected by the present method. This mutation was not found in the remaining one with alpha-thalassemia compound Hb Q. We also used this assay to analyse DNA samples from cord blood in 6 pregnancies at risk of Bart's hydrops fetalis, in 1 at risk of Hb H disease for prenatal diagnosis.
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PMID:[Molecular screening and prenatal diagnosis of the deletional alpha-thalassemia by polymerase chain reaction amplification]. 799 62

We have developed a rapid method to molecularly distinguish different types of Hb H disease. The study depended on (a) most of the Hb H disease in Taiwan having an alpha-thalassemia-1 of the Southeast Asia type (--SEA) in one allele and (b) the differences of X box of alpha-globin gene cluster in the other allele. To detect the --SEA allele, we utilized the primers located on either side of the breakpoint to do PCR, then characterized the amplified products. For the other allele, we sequenced part of the X box, and found that bases -2803 to -2461 of the X box of -alpha 3.7 belonged to the X box of alpha 2 globin gene. In -alpha 4.2, the bases belonged to the X box of alpha 1 globin gene, whereas in alpha CS alpha it contained both X boxes of alpha 1 and alpha 2 globin genes. There was an MboII site at this region of the X box of alpha 2 globin gene. We utilized PCR to amplify this region and digested it with restriction enzyme MboII, then combined it with another PCR of different types of Hb H disease. One hundred and one cases of Hb H disease from different families were studied: all of the cases had one allele of --SEA deletion, while the other allele showed that 52/101 were -alpha 3.7, 41/101 were alpha CS alpha, 7/101 were -alpha 4.2, and 1/101 was -alpha G. Taichung. Of 52 cases of Hb H with -alpha 3.7, 47 were type-I deletion and five were type-II deletion.
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PMID:Rapid molecular characterization of Hb H disease in Chinese by polymerase chain reaction. 811 Aug 77

Variable number of tandem repeats (VNTR) loci are among the most polymorphic sequences described to date. VNTR allelic variability is a function of the high rates of de novo mutation due to intra- and inter-allelic recombination. We have assessed the allelic stability of VNTRs during recent human evolution, focusing on the relationship between an alpha-thalassaemia-1 deletion that is common among South-East Asian populations (--SEA/) and a VNTR located immediately down-stream of the alpha-globin gene cluster (3'alpha HVR). More than 50 unrelated (--SEA/) carriers were analyzed using a strategy that allowed the unambiguous assignment of a carrier's 3'alpha HVR alleles to either the normal or the (--SEA/) chromosome. The analysis revealed that 89% of the (--SEA/) chromosomes are associated with 3'alpha HVR alleles that fall within a limited size range (5,415-6,442 bp for PvuII digests). In contrast, only 4% of the carriers' normal chromosomes are associated with 3'alpha HVR alleles of this size range, and surveys of other racial and ethnic populations confirm that these 3' alpha HVR alleles are uncommon in general. Overall, these data indicate that the (--SEA/) deletion originally occurred on a chromosome marked by a rare 3'alpha HVR allele, and that this association has been relatively stable over the course of recent human evolution in South-East Asia.
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PMID:Allelic stability of VNTR locus 3' alpha HVR: linkage disequilibrium with the common alpha-thalassaemia-1 deletion of South-East Asia (--SEA/). 818 11

The most common alpha-thalassemia in Southeast Asian or Southern Chinese populations is the (--SEA) double alpha-globin deletion. Couples heterozygous for (--SEA) have 25% risk for hydrops fetalis from loss of all four alpha-globin genes. The (--SEA) deletion spares the embryonic zeta-globin genes and causes traces of zeta-peptide to persist throughout life. A colorimetric monoclonal anti-zeta antibody test for raised zeta-peptide has detected the (--SEA) deletion in liquid blood samples, but not deletions of the entire alpha-globin region with loss of the zeta-globin genes. Eluates from dried blood spots had the same anti-zeta antibody color reaction as whole blood, even after storage at 4 degrees C for up to 77 days. The anti-zeta antibody test was positive in 24 of 91 microcytic samples (mean corpuscular hemoglobin < 24 pg), including four with iron deficiency; it was negative in 26 provisionally diagnosed alpha-thalassemia-1 heterozygotes and all 32 nonmicrocytic samples. Southern blot analysis and a specific SEA-polymerase chain reaction test confirmed that 18 anti-zeta antibody-positive samples and 1 anti-zeta antibody-negative sample had the (--SEA) deletion. Two anti-zeta antibody-negative microcytic samples had the (--Fil) total alpha-globin region deletion, 2 had single alpha-gene deletions, 22 others may also have had a total alpha-region deletion. Hence specificity was very high and sensitivity was 95%. The anti-zeta antibody test can detect the (--SEA) deletion in dried blood samples, even after prolonged storage. This simple inexpensive test can conveniently screen samples collected at a distance from a central laboratory.
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PMID:Anti-zeta antibody screening for alpha-thalassemia using dried filter paper blood. 819 21

The molecular basis of alpha(0) thalassemia were studied in 95 patients who attended at Srinagarind Hospital, Khon Kaen University during September 1993-January 1994. From these 95 patients, hemoglobin electrophoresis indicated that there were 14 cases with A2AH, 21 cases with A2ABart'sH, 6 cases with ConSpA2AH, 31 cases with ConSpA2ABart'sH, 6 cases with EABart's, 3 case with EFBart's, 4 cases with ConSpEABart's, 5 cases with Portland Bart's and 5 cases with A2A. White blood cell lysate was prepared from peripheral blood leukocytes of these patients and was subjected to the polymerase chain reactions for detection of the SEA type alpha thalassemia gene deletion. Altogether 100 chromosomes with the SEA deletion were detected from all patients examined, the result indicated that this type of alpha(0) thalassemia gene deletion is the most common among these Thai population. These data will be useful for a carrier screening and a prenatal diagnosis program of homozygous alpha (0) thalassemia which is a lethal condition in northeast of Thailand.
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PMID:Molecular basis of alpha (0)-thalassemia in northeast of Thailand. 862 16

Hb Q (alpha 74Asp-His) results from a mutation in the alpha-gene such that abnormal alpha Q-chains are synthesized. The alpha Q-chains combine with the normal Beta A-chains to form abnormal Hb alpha 2Q beta 2A (Hb Q). Hb Q-H disease is rare, and has been reported only in the Chinese. We report here a Chinese family, were the mother diagnosed with Hb Q-H disease and the father with Hb E heterozygosity and a child with Hb Q-E-thalassemia. Thalassemia screening of the mother's blood revealed a Hb level of 6.8g/dl with low MCV and MCH. Her blood film was indicative of thalassemia. Cellulose acetate electrophoresis showed Hb H and Hb Q with the absence of Hb A. Globin chain biosynthesis was carried out and alpha Q- and beta-chains were detected. Normal alpha- chains were absent. Digestion of the mother's DNA with Bam HI and Bgl II followed by hybridization with the 1.5 kb alpha-Pst probe showed a two alpha-gene deletion on one chromosome and the -alpha Q chain mutant with the -alpha 4.2 defect on the other chromosome. DNA amplification studies indicated the two-gene deletion to be of the -SEA/ defect. The patient was concluded to possess Hb Q-H disease (--SEA/-alpha 4.2Q). Cellulose acetate electrophoresis of the father's blood showed the presence of Hb A, F and E. Molecular analysis of the father's DNA confirmed an intact set of alpha-genes (alpha alpha/alpha alpha). Globin chain biosynthesis of fetal blood of their child showed gamma, beta A, beta E, alpha A and alpha Q-chains. Molecular analysis of the child's DNA showed one alpha-gene deletion, thus giving a genotype of alpha alpha/-alpha 4.2Q beta beta E.
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PMID:Molecular analysis of Hb Q-H disease and Hb Q-Hb E in a Singaporean family. 862 17

The population of northern Thailand has one of the highest frequencies of alpha-thalassemia in the world. However, the available distributional data are controversial. In addition to deletional types of alpha-thalassemia Hb, type Constant Spring should also be taken into consideration in alpha-thalassemia population studies, because it causes clinical alpha-thalassemia in the homozygous state or when present with both alpha-globin genes deleted in trans. We have examined a sample of 215 healthy subjects from four rural districts of Chiang Mai province. Out of these, 77 exhibited anomalies of the alpha-globin genes (alpha alpha/-alpha 3.7 in 36; -alpha 3.7/-alpha 3.7 in 3; -SEA in 30; alpha alpha/alpha CS alpha in 5; alpha alpha alpha anti 3.7 in 3). Therefore, no fewer than 2% of the children in northern Thailand are expected to be born with HbH disease or thalassemic hydrops fetalis. The considerable public health problem of hemoglobinopaties and the increasing acceptance of family planning necessitates facilities for the pre- and postnatal diagnosis of these disorders at the DNA level.
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PMID:Prevalence of alpha-thalassemias in northern Thailand. 870 7

We have estimated the incidence and molecular basis of alpha-thalassemia in a Portuguese population, mostly from the Greater Lisbon area. In a group of 100 consecutive cord blood samples, the gene frequency of the rightward deletion (-alpha 3.7) was 0.035, and the leftward deletion (-alpha 4.2) was 0.015. In this group, we have also found four heterozygotes for the triple alpha-globin gene rearrangement (alpha alpha alpha anti 3.7. gene frequency 0.020). We have characterized the subtypes of -alpha 3.7 and alpha alpha alpha anti 3.7 rearrangements. On the whole, these results give an incidence of 10% for deletional alpha-thalassemia carriers in the studied Portuguese population. In a group of 342 subjects presenting beta-thalassemia, or Hb S trait, beta-thalassemia major sickle cell disease or low red blood cell indices, the -alpha 3.7, -alpha 4.2, -SEA, -MED, (alpha alpha)MM, and alpha alpha alpha anti 3.7 haplotypes were found in different combinations. Only one nondeletional alpha-thalassemia determinant (a 5 nucleotide deletion in the alpha 2-globin gene in the second intervening sequence donor site) was detected, which might suggest a low incidence of these defects in the Portuguese population.
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PMID:Molecular basis of alpha-thalassemia in Portugal. 871 93


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