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)

The alpha globin genotypes of 55 beta thalassaemia heterozygotes have been determined by restriction endonuclease analysis to identify those with interacting alpha thalassaemia genes. A comparison of the haematological and haemoglobin synthesis findings of individuals with normal alpha genotypes (alpha alpha/alpha alpha) with those with one (-alpha/alpha alpha) or two (-alpha/-alpha) alpha genes deleted shows that the latter two groups have more balanced globin chain synthesis ratios, higher haemoglobin levels, and larger, better haemoglobinized red cells. This suggests that the degree of globin chain imbalance is a significant factor in determining the red cell characteristics in heterozygous beta thalassaemia. Screening programmes for thalassaemia, based on the detection of low MCVs, could miss cases of the interaction of alpha and beta thalassaemia.
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PMID:The interaction of alpha thalassaemia with heterozygous beta thalassaemia. 628 63

A symptomless Iranian patient homozygous for beta thalassaemia has haematological changes similar to the beta thalassaemia trait. This remarkably mild phenotype is probably the result of coexistent alpha thalassaemia and increased gamma chain synthesis. Restriction endonuclease mapping analysis of the beta globin genes indicates that the patient is homozygous for a single nucleotide substitution at the 5' donor splice junction in the second intervening sequence of the beta globin gene. No other changes were observed in the non-alpha globin gene cluster. It seems unlikely that the augmented gamma chain synthesis in this patient is related to the molecular defect responsible for this beta o thalassaemia.
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PMID:The molecular basis for beta o thalassaemia intermedia in an Iranian individual. 628 64

Microcytic red cells from a 70 year old Negro man with mild anemia contained only hemoglobin G-Philadelphia. Red cells from all of his children had low-normal MCV's, and contained 32-34 percent of the abnormal hemoglobin. Oxygen affinity of his blood and stability of his hemolysate were normal, suggesting that his mild anemia was not caused by the the abnormal hemoglobin. Restriction endonuclease analyses of DNA from the proband and his offspring showed that the alpha G-Philadelphia globin gene exists in only one copy per chromosome. The new gene was probably created by an unequal cross-over which deleted an alpha globin coding sequence (derived from one or both alpha globin genes), as well as some or all of the DNA sequence between those genes.
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PMID:Homozygous alpha thalassemia/Hb G Philadelphia. 629 2

This paper reports the results of alpha globin gene analysis in a Sardinian family with interacting alpha and beta thalassaemia genes. The propositus, who was identified in a newborn survey as he had 26.0% Hb Bart's and 74.0% Hb F, successively developed the clinical and haematological picture of a transfusion-dependent thalassaemia major. According to the haemoglobin pattern, restriction endonuclease analysis of the DNA from this patient showed the deletion of three of the four alpha-globin structural genes. Thus beta 0-thalassaemia homozygotes with the delection of three alpha-structural genes seem to have a severe clinical phenotype similar to that of patients with a full complement of four alpha-globin structural genes.
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PMID:Alpha globin gene analysis in a Sardinian family with interacting alpha and beta thalassaemia genes. 629 25

In this study we used restriction endonuclease mapping to characterise the molecular defect responsible for haemoglobin H disease in 14 Sardinian children. The resulting genotypes were then correlated with the respective clinical and haematological phenotypes. We found that patients with the combination of non-deletion alpha(+)-thalassaemia [(alpha alpha)th] and deletion alpha(0)-thalassaemia (-Med) have a more severe phenotype than that resulting from the interaction of deletion alpha(0)-thalassaemia (-Med) and alpha(+)-thalassaemia (-alpha) determinants. Clinically, presentation was earlier and with moderate anaemia or haemolytic crisis, enlargement of the liver and spleen, and thalassaemic bone changes. Haematologically, the anaemia was more severe and there were higher bilirubin levels, reticulocyte counts, Hb H levels, and percentage of red blood cells with inclusion bodies. These results suggest that in those Hb H disease patients with the non-deletion [(alpha alpha)th] determinant, two alpha globin genes produce fewer alpha globin chains than a single alpha globin locus.
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PMID:Phenotype-genotype correlation in haemoglobin H disease in childhood. 631 63

The presence of the alpha-globin frameshift mutant, Hb Wayne, in three generations of a second family is described. The data include a hematological evaluation of the four heterozygotes, structural characterization of the variant, the use of HPLC for the separation of tryptic and chymotryptic peptides, functional analyses of the isolated variant showing high affinity for oxygen and the (near) absence of a Bohr effect, and alpha chain gene organization analyses with restriction endonuclease technology suggesting that the Hb Wayne heterozygote has a full complement of four alpha globin genes.
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PMID:Hb Wayne, the frameshift variant with extended alpha chains observed in a Caucasian family from Alabama. 632 75

In HbSC disease, as in sickle cell anaemia, there is a spectrum of clinical severity. A reduced mean corpuscular volume and haemoglobin concentration, traits typical of thalassaemia, might retard sickling. We therefore ascertained the prevalence of alpha-thalassaemia in 53 adults with HbSC disease and related alpha-globin gene deletion to the haematologic and clinical findings. Alpha-globin genotype was identified by restriction endonuclease gene mapping. Indirect ophthalmoscopy and fluorescein angiography were used to document the presence of proliferative retinopathy. Bone necrosis and infarction were determined roentgenographically or by radionuclide scanning. Either heterozygous or homozygous alpha-thalassaemia-2 was present in 26% of patients. There was no relationship between alpha-globin genotype and haematocrit, pain crises, bone lesions, proliferation retinopathy or clinical severity score.
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PMID:The effects of alpha-thalassaemia in HbSC disease. 663 90

Nucleotide sequence analysis of a recombinant cDNA for a duck alpha-globin gene indicates a gene with novel features and evolutionary history. The duck alpha-globin double-stranded cDNA, treated with S1 nuclease and tailed with poly(dC), was inserted into the PstI restriction endonuclease site of pBR322 tailed with poly(dG). Nucleotide sequence analysis of the resulting recombinant cDNA indicates that it contains the translated region and all of the 3' untranslated region for an alpha-globin gene. The sequence was determined by procedures designed especially for rapid analysis of pBR322 (PstI site) recombinant cDNAs. This duck globin has sequences related to the chicken alpha-A globin in some regions but in other regions it is more closely related to another alpha globin found in anemic chickens.
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PMID:Nucleotide sequence for a novel duck alpha-globin gene. 689 64

A Chinese family has been studied in which two siblings have haemoglobin Q-H disease. Using a combination of haematological and haemoglobin analysis, globin chain synthesis, analysis of alpha/beta globin messenger RNA ratios and restriction endonuclease mapping, it has been shown that each of these siblings has received one chromosome on which both alpha chain genes have been deleted and another on which there is only a single alpha chain locus which carries the alpha Q mutation. Their genotype is thus --/-alpha Q. Despite the fact that the haemoglobin Q mutation in this family is carried on a chromosome with a single alpha chain locus, heterozygous carriers for the variant have only 25% or less haemoglobin Q. Our observations indicate that the molecular basis for haemoglobin Q-alpha thalassaemia is similar to that for the common form of haemoglobin H disease in Orientals. Furthermore, they provide clear evidence that the level of an alpha chain variant in heterozygous carriers is not a reliable reflection of the number of alpha globin genes.
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PMID:The genetic basis of Hb Q-H disease. 744 25


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