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D J Weatherall

Publications and source records attributed to D J Weatherall.

At least 271 records · Page 15Linked to original sources
PubMed1982

alpha-globin gene deletions associated with Hb J Tongariki.

Three identical alpha + thalassemia genes, one of which always carried the Hb J Tongariki mutation, have been observed in Vanuatuans. Despite the fact that at least two of them have arisen by different types of crossover event, the expression of all three haplotypes is identical.

Chromosome Deletion↗
PubMed1981

A novel rearrangement of the human beta-like globin gene cluster.

The first example of a duplication involving the human beta-like globin genes has been characterised in DNA from a native of Vanuatu. Restriction endonuclease mapping has shown that a 5 kb insert of DNA in the gamma-delta-beta gene cluster is due to duplication of the Ggamma-globin gene and results in a new rearrangement 5'-epsilon-Ggamma-Ggamma-Agamma-delta-beta-3'.

Adult↗
PubMed1981

Restriction mapping of a new deletion responsible for G gamma (delta beta)o thalassemia.

DNA from individuals heterozygous for (G)gamma(deltabeta)(o) thalassaemia has been studied by restriction endonuclease analysis. The results reveal a new molecular defect associated with this condition. A total of three defects is now responsible for the one single phenotype, thereby emphasising the complex relationship between genotype and phenotype among the disorders of beta-like globin synthesis in man.

Chromosome Deletion↗
PubMed1981

Highly variable regions of DNA flank the human alpha globin genes.

A series of restriction fragment length polymorphisms which are due to DNA rearrangements have been identified within two highly variable regions flanking the human alpha globin genes. The existence of such highly polymorphic areas provides a large number of individual genetic markers for the alpha globin gene cluster on chromosome 16. If, as seems likely, such regions occur frequently throughout the human genome they should be of considerable value in the antenatal diagnosis of genetic disease.

Chromosomes, Human, 16-18↗
PubMed1981

Hemoglobin H disease and mental retardation: a new syndrome or a remarkable coincidence?

Each of three families of northern European origin contains a mentally retarded son with hemoglobin H (Hb H) disease. One parent is a carrier of mild alpha-thalassemia and the other is normal, suggesting that this form of Hb H disease results from the interaction between an inherited defect of alpha-chain production and one member of the pair in chromosome 16 and a new mutation on the other. Restriction-enzyme analysis indicated that the new mutation was not the same in the other three patients, and demonstrated at least two hitherto undescribed lesions involving the alpha-globin gene cluster. Unless the association between the Hb H disease and mental retardation is fortuitous, the new mutations may also be related to the development changes in these children. Since the mutations only came to light because there was concurrent inheritance of an additional alpha-thalassemia determinant, this type of mutation of chromosome 16 may have been overlooked in other mentally retarded patients.

Adult↗
PubMed1981

Molecular basis for mild forms of homozygous beta-thalassaemia.

Five Cypriots homozygous for beta +-thalassaemia have inherited deletion or non-deletion forms of alpha-thalassaemia that seem to have modified the usually severe clinical picture to that of mild thalassaemia intermedia. These observations have important implications for the antenatal diagnosis of beta-thalassaemia.

Adolescent↗
PubMed1981

Embryonic erythroid differentiation in the human leukemic cell line K562.

K562 human leukemia cells synthesize embryonic hemoglobins after culture in the presence of hemin. We have rigorously identified these hemoglobins by globin chain analysis and peptide mapping. No adult hemoglobin could be detected, and beta-globin synthesis was less than 2 ppm of total protein synthesis. Persistent embryonic globin gene expression is known to occur as a consequence of globin gene deletions. However, restriction endonuclease mapping showed that the globin gene complexes in K562 cells are indistinguishable from normal. Hemin increased the rate of embryonic globin synthesis. The pattern of hemoglobin synthesis proved to be stable when cells from different laboratories were compared. One line, however, synthesized large amounts of Hb X and very little Hb Portland in response to hemin. Hb X has been previously detected in human embryos; we show here that it has the composition epsilon 2 gamma 2 and is diagnostic of imbalanced chain synthesis or "zeta thalassemia." We have identified several agents that induce hemoglobin synthesis in K562 cells. Different inducers induced different patterns of embryonic hemoglobin synthesis but never any adult hemoglobin synthesis.

Cell Differentiation↗
PubMed1981

Genetic and molecular diversity in nondeletion Hb H disease.

Restriction endonuclease mapping of nondeletion alpha-thalassemia determinants from a variety of racial groups showed no detectable abnormalities within a 40-kilobase region of the zeta-alpha globin gene cluster. By using a zeta-specific probe, we defined three different types of interactions that give rise to Hb H disease, each involving a nondeletion alpha-thalassemia haplotype. mRNA analysis showed further diversity within these groups, indicating that there are at least three nondeletion determinations.

Chromosome Deletion↗
PubMed1981

The genetics and molecular basis of alpha thalassaemia in association with Hb S in Jamaican Negroes.

We have studied seven Jamaican Negro families in whom the genes for alpha thalassaemia and the sickle cell mutation (betas) were independently segregated. Using a combination of techniques we identified two alpha thalassaemia phenotypes which resemble the severe (alpha thalassaemia 1) and mild (alpha thalassaemia 2) determinants previously described in Orientals. This study has enabled us to clearly correlate the phenotype of alpha thalassaemia with the genotype in this population. Furthermore, since in each family alpha thalassaemia was present in association with the gene for the sickle cell mutation we have determined the proportion of Hb S in the peripheral blood of individuals with the alpha alpha/alpha alpha, -alpha/alpha alpha and -alpha/-alpha genotype who are also heterozygous for the betas mutation. Genetic analysis in these families shows that in each case subjects with the alpha thalassaemia 1 phenotype are homozygous for the alpha thalassaemia 2 defect (-alpha/-alpha). We have found no instances of the genotype --/alpha alpha in this population which may explain the rarity of the severe alpha thalassaemia syndromes in Jamaica. Restriction mapping data in the alpha thalassaemia 2 homozygotes from this population shows that the (-alpha/) haplotype results from a deletion of one of the linked pair of alpha globin genes and that this has probably arisen by an unequal crossover between non-homologous alpha genes.

Black People↗