Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An Azorean family with Hb H disease (10% Hb H) was studied in order to elucidate its molecular basis. DNA studies on the patient only revealed a 4.2 kb "leftward" deletion of paternal origin which implies the co-inheritance of a nondeletional alpha-thalassemia determinant. Restriction endonuclease and oligonucleotide analysis allowed the exclusion of five point mutations: initiation codon (at both alpha 1- and alpha 2-globin genes), IVS-I donor splice junction pentanucleotide deletion, codon 125 CTG----CCG substitution, and Saudi Arabian polyadenylation signal mutation. These findings suggest that the molecular basis of this form of Hb H disease is probably different from those described previously.
Hemoglobin 1990
PMID:Unusual molecular basis of Hb H disease in the Azores Islands, Portugal. 210 37

Data were obtained on blood samples from a relatively large group (264) of healthy Japanese newborns, collected at hospitals in Tokyo, Kurashiki, and Ube. The studies included an evaluation of anomalies in alpha-globin gene and gamma-globin gene arrangements using gene mapping and gamma-chain composition analyses. The results confirmed the rarity of alpha-thalassemia among Japanese; only a few babies had alpha-thalassemia-2 trait (the -3.7-kilobase [kb] deletion), while others had alpha-globin gene triplications (both the alpha alpha alpha anti-3.7 and the alpha alpha alpha anti-4.2 types). Among the gamma-globin gene anomalies that were observed, a few babies had the -A gamma-A gamma- globin gene arrangement or the -G gamma A gamma- type of deletion. The gamma-chain triplication (-G gamma-A gamma G gamma-A gamma-) occurred in 10 out of 256 newborns, and its frequency exceeded that of its corresponding -G gamma A gamma- deletion by a factor of 5. The restriction endonuclease XmnI was a useful tool, in addition to the enzymes Bg1II and BclI, to evaluate and confirm the gamma-globin gene deletion and triplication. The A gamma T variant, which is the product of a mutant A gamma-globin gene, occurred at a frequency of 0.156. The chromosome carrying this mutant A gamma gene had a characteristic haplotype that was originally seen in black and Mediterranean patients with Hemoglobin (Hb) S or with beta-thalassemia.
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PMID:Abnormal arrangements in the alpha- and gamma-globin gene clusters in a relatively large group of Japanese newborns. 241 79

The purpose of the present study was to investigate the effect of alpha-thalassemia on the prevalence of avascular necrosis in 52 adult patients with sickle cell anemia. alpha-Globin genotypes were determined by restriction endonuclease mapping of genomic DNA extracted from peripheral blood leukocytes. Radiographs of humeral and femoral heads were interpreted by two radiologists who were not aware of the clinical picture and the genotype of the patients in the study. We present data showing that there is a significant positive correlation between alpha-gene deletion and the prevalence and extent of avascular necrosis in our patient population.
Hemoglobin 1989
PMID:The prevalence of avascular necrosis in sickle cell anemia: correlation with alpha-thalassemia. 263 66

Hemoglobin H (HbH) disease is most often due to deletion of three of the four alpha-globin genes (genotype --/--alpha). In black subjects although the -alpha/chromosome is common, the --/haplotype is very rare and few examples of HbH disease have been detected. We have studied three black siblings with HbH by restriction endonuclease mapping of the alpha-like gene complex (5'-zeta-psi zeta-psi alpha 2-psi alpha 1-alpha 2-alpha 1-3') using zeta- and alpha- specific probes. The presence of size differences in the previously described hypervariable region between the zeta and psi zeta genes results in a restriction fragment length polymorphism which permitted the detection of single alpha genes on both number 16 chromosomes in these subjects. Quantitative DNA hybridization by a slot-blot technique confirmed that their genomes contained two alpha-globin genes. The results establish that in these black subjects HbH disease is associated with dysfunctional alpha-globin genes (genotype: -alpha/-alpha T).
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PMID:Dysfunctional alpha-globin genes in hemoglobin H disease in blacks: variation in restriction fragment size permits the detection of the -alpha/-alpha T genotype. 289 Dec 96

Using DNA dot-blot hybridization, restriction endonuclease gene mapping with oligonucleotide probes, restriction fragment length polymorphism linkage analysis, and hybridization, prenatal diagnosis was performed for 32 pregnancies at risk for alpha-thalassemia and for 10 pregnancies at risk for beta-thalassemia. The DNA samples were prepared from chorion villi or amniotic fluid cells.
Hemoglobin 1988
PMID:Prenatal diagnosis of thalassemia: experiences at the Shanghai Children's Hospital. 290 48

A relationship between Hb Bart's levels in cord blood and the number of alpha-globin genes has been established by screening cord blood samples from 1,075 newborn babies. Diagnosis was made by gene mapping of DNA samples with restriction endonuclease digestion. The presence of Hb Bart's was determined with a discontinuous microelectrophoresis on cellulose acetate at pH 8.34. The establishment of this relationship allows an early diagnosis of alpha-thalassemia by this simple microelectrophoretic procedure.
Hemoglobin 1988
PMID:The relationship between Hb Bart's levels in cord blood and the deletions of alpha-globin genes. 320 94

Members of a Black family from Georgia who were investigated for the first time in 1960 and several times thereafter were reinvestigated through DNA restriction endonuclease analyses and haplotyping, while the gamma chain heterogeneity of the Hb F was reevaluated using a newly developed HPLC procedure. Four different abnormalities were present. (a) Heterozygosity for G gamma A gamma-HPFH type II characterized by a large deletion involving the delta and beta globin genes with a 5' end within the psi beta gene. (b) Heterozygosity for an -epsilon-G gamma-G gamma-psi beta-delta-beta S-chromosome, thus carrying a beta S globin gene and two G gamma genes instead of one G gamma and one A gamma gene. (c) Heterozygosity for an -epsilon-G gamma-A gamma T-psi beta-delta-beta S-chromosome, carrying the beta S globin gene and an allele of the A gamma (or A gamma I) gene. These three chromosomes occurred in combination with each other, resulting in SS and S-HPFH conditions, and with a normal -epsilon-G gamma-A gamma-psi beta-delta-beta A-chromosome resulting in the HPFH and Hb S heterozygosities. The presence of the -G gamma-G gamma- and -G gamma-A gamma T-chromosomes in the one SS patient was responsible for the high G gamma value (average 75%), 25% A gamma T chain, and for the absence of the A gamma I chain. (d) An alpha-thalassemia-2 heterozygosity in one member.
Hemoglobin 1984
PMID:Hemoglobin abnormalities in a black family with HB S, hereditary persistence of HB F, and a gamma chain variant; a reevaluation through gene mapping. 608 52

Twenty-six DNA samples from individuals either heterozygous or homozygous for beta thalassemia were analyzed by restriction endonuclease digestion, agarose gel electrophoresis, and Southern blot analysis to define DNA fragments containing portions or all of the beta globin gene. A total of twenty-seven genes affected by a beta thalassemia mutation and twenty-seven genes affected by a beta thalassemia mutation and twenty-two normal beta globin genes were examined in Italian, Greek, or Asian individuals. With all four restriction endonucleases used, the fragments generated from DNA of thalassemic individuals were identical to those found in DNA from normal. Thus, gross rearrangement or deletion within the genomic region containing the beta globin gene is not characteristic of mutations which cause a thalassemia. A third patient homozygous for pancellular hereditary persistence of fetal hemoglobin was shown to have complete deletion of the delta and beta globin genes.
Hemoglobin 1981
PMID:Analysis of globin gene structure in patients with beta thalassemia by restriction endonuclease mapping. 616 67

In this study, we have correlated the hematological phenotype of 56 Sardinian beta o-thalassemia heterozygotes with their alpha-globin genotype as defined by restriction endonuclease mapping. We found that the coinheritance of the deletion of one alpha-globin and, more obviously, two alpha-globin genes tend to normalize the thalassemia-like hematological phenotype commonly associated with the beta o-thalassemia carrier state. On the other hand, the association of the deletion of three alpha-globin genes caused a more severe phenotype. By globin chain synthesis analysis, those beta o-thalassemia heterozygotes with the (-alpha/alpha alpha) alpha-globin genotype had less deficiency of beta-chain synthesis than did those with the normal alpha-globin genotype (alpha alpha/alpha alpha). In heterozygotes with the (-alpha/-alpha) and in those with the (--/-alpha) alpha-globin genotype the imbalance was actually reversed with a mild or marked alpha-chain synthesis excess respectively.
Hemoglobin 1984
PMID:Hematological phenotype of the double heterozygous state for alpha and beta thalassemia. 620 59

Hemoglobin A2 levels in normal adults are rarely greater than 3.5%. In patients heterozygous for beta-thalassemia, they average about 5% but do not usually exceed 7%. We studied a family in which four patients with heterozygous beta-thalassemia had HbA2 levels of 8.4% to 11.2%. Globin biosynthesis studies and restriction endonuclease mapping of the alpha-globin loci showed homozygous or heterozygous alpha-thalassemia-2 as well as beta-thalassemia in some family members. The delta- and beta-globin genes were examined by using the restriction enzymes Eco RI, Pvu II, and Xba I, which cut both within and outside the coding portions of the delta- and beta-loci. Only the expected delta- and beta-globin gene containing fragments were present, excluding a crossover event producing a fusion gene that would code for delta-globin but possibly be under the regulatory influence of nucleotide sequences that control the expression of the beta-gene. This kindred provides evidence that in the presence of beta-thalassemia, expression of the delta-gene, beyond that commonly seen, is possible. This could be a direct result of the gene defect producing beta-thalassemia or be due to differences in the delta-globin gene linked to this beta-thalassemia gene. The interactions of alpha- and beta-thalassemia may alter tetramer assembly and increase HbA2 levels; however, this possibility seems less likely.
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PMID:Beta-thalassemia with exceptionally high hemoglobin A2. Differential expression of the delta-globin gene in the presence of beta-thalassemia. 628 19


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