Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

Query: UMLS:C0019045 (hemoglobinopathies)
2,704 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Somatic gene therapy of hemoglobinopathies depends initially on the demonstration of safe, efficient gene transfer and long-term, high-level expression of the transferred human beta-globin gene in animal models. We have used a beta-globin gene/beta-locus control region retroviral vector containing several modifications to optimize gene transfer and expression in a mouse transplant model. In this report we show that transplantation of beta-globin-transduced hematopoietic cells into lethally irradiated mice leads to the continued presence of the gene up to 8 months posttransplantation. The transferred human beta-globin gene is detected in 3 of 5 mice surviving long term (>4 months) transplanted with bone marrow cells transduced with high-titer virus. Southern blotting confirms the presence of the unrearranged 5.1-kb human beta-globin gene-containing provirus in 2 of these mice. In addition, long-term expression of the transferred gene is seen in 2 mice at levels of 5% and 20% that of endogenous murine beta-globin at 6 and 8 months posttransplantation. We further document stem cell transduction by the successful transfer and high-level expression of the human beta-globin gene from mice transduced 9 months earlier into irradiated secondary recipient mice. These results demonstrate high-level, long-term somatic human beta-globin gene transfer into the hematopoietic stem cells of an animal for the first time, and suggest the potential feasibility of a retroviral gene therapy approach to sickle cell disease and the beta thalassemias.
...
PMID:Long-term transfer and expression of the human beta-globin gene in a mouse transplant model. 934 24

In this report we describe the molecular analysis of 795 chromosomes derived from unrelated Turkish beta-thalassemia and sickle cell anemia carriers identified in hematology clinics in Istanbul, Ankara, Izmir, Adana, and Antalya. The determination of the molecular pathology of 754 beta-thalassemia and 42 abnormal hemoglobin genes and analysis of the frequency distribution in six distinct regions of Turkey was accomplished. The experimental strategy, based on PCR amplification of the beta-globin gene, included dot-blot hybridization with 18 probes specific for the Mediterranean populations, denaturing gradient gel electrophoresis, and genomic sequencing. When the regional results are compared with the overall frequency of mutations in the country, it is observed that the frequencies in the western and southern parts of Turkey are in good accordance with the overall distribution, whereas the northern and eastern parts have a more region/population-specific profile with some rare mutations having a significantly high occurrence in these regions. Further evaluation of the data with respect to region- or population-dependent differences will contribute to a better understanding of the mechanisms leading to the marked genetic heterogeneity in Turkey, but could also be extremely valuable in facilitating rapid identification of mutations in families at risk for different hemoglobinopathies.
...
PMID:Molecular and population genetic analyses of beta-thalassemia in Turkey. 949 72

Hemoglobinopathies, such as beta-thalassemias and sickle cell anemia (SCA), are among the most common inherited gene defects. Novel models of human erythropoiesis that result in terminally differentiated red blood cells (RBCs) would be able to address the pathophysiological abnormalities in erythrocytes in congenital RBC disorders and to test the potential of reversing these problems by gene therapy. We have developed an in vitro model of production of human RBCs from normal CD34(+) hematopoietic progenitor cells, using recombinant growth factors to promote terminal RBC differentiation. Enucleated RBCs were then isolated to a pure population by flow cytometry in sufficient numbers for physiological studies. Morphologically, the RBCs derived in vitro ranged from early polylobulated forms, resembling normal reticulocytes to smooth biconcave discocytes. The hemoglobin pattern in the in vitro-derived RBCs mimicked the in vivo adult or postnatal pattern of beta-globin production, with negligible gamma-globin synthesis. To test the gene therapy potential using this model, CD34(+) cells were genetically marked with a retroviral vector carrying a cell-surface reporter. Gene transfer into CD34(+) cells followed by erythroid differentiation resulted in expression of the marker gene on the surface of the enucleated RBC progeny. This model of human erythropoiesis will allow studies on pathophysiology of congenital RBC disorders and test effective therapeutic strategies.
...
PMID:An in vitro model of human red blood cell production from hematopoietic progenitor cells. 953 74

Sickle cell anemia is the most common heritable hematological disease, yet no curative treatment exists for this disorder. Moreover, the intricacies of globin gene expression have made the development of treatments for hemoglobinopathies based on gene therapy difficult. An alternative genetic approach to sickle cell therapy is based on RNA repair. A trans-splicing group I ribozyme was used to alter mutant beta-globin transcripts in erythrocyte precursors derived from peripheral blood from individuals with sickle cell disease. Sickle beta-globin transcripts were converted into messenger RNAs encoding the anti-sickling protein gamma-globin. These results suggest that RNA repair may become a useful approach in the treatment of genetic disorders.
...
PMID:Ribozyme-mediated repair of sickle beta-globin mRNAs in erythrocyte precursors. 961 20

In order to provide population genetic data of various ethnic groups in Thailand, we have determined the type of hemoglobin by electrophoresis and the beta-globin gene haplotypes by PCR followed by restriction digestion in five small ethnic groups namely hill tribes, PhuTai, Chong, Lao Song and Sakai inhabiting in the north, northeast, east, central and south of Thailand, respectively. In each group, in addition to HbA and HbA2, the HbE, the most common hemoglobinopathy in Southeast Asia was detected at 2.5%, 51.6%, 84.0%, 8.6% and 11.8%, respectively. Haplotype analysis demonstrated that in all groups the beta A-globin gene was associated with various haplotypes and beta-globin gene frameworks. However, beta E -globin gene was associated with haplotypes ((-)+(-)+ + +(-)) and ((+)-(-)-(-)+(-)) on the beta-globin gene framework 2 in all ethnic groups except in Chong people whose the beta E-globin gene was mostly linked to haplotype ((-)+(-)++(-)+) and beta-globin gene framework 3 which was commonly found among Cambodian. It appears therefore that the Chong population is more related to Cambodian than Thai.
...
PMID:Beta-globin gene haplotypes in some minor ethnic groups in Thailand. 964 Jun 12

Beta-thalassemia is one of the most common inherited hemoglobin disorders in Pakistan. The carrier frequency is estimated to be 5.4%. To determine the spectrum of beta-globin gene defects causing beta-thalassemia, we have analyzed a representative sample of 602 alleles from six ethnic groups in Pakistan; 99.2% alleles were characterized, while 0.8% remained unidentified. The spectrum of mutations is heterogeneous and we have found 19 different mutations in all ethnic groups. The four most common mutations, IVS-I-5 (G-->C) (37.7%), codons 8/9 (+G) (21.1%), the 619 bp deletion (12.4%), and IVS-I-1 (G-->T) (9.5%), account for 80.7% of the alleles. There are differences between the ethnic groups and also between provinces. In the four provinces of Pakistan, the IVS-I-5 (G-->C) mutation is more prevalent in Sindh and Balochistan, bordering India in the south and Iran in the southwest, while the codons 8/9 (+G) mutation is more common in the Punjab and the North West Frontier Province, bordering India in the northeast and Afghanistan, respectively. The 619 bp deletion is high (46%) in Gujratis and Memons residing in the Province of Sindh, neighboring the Indian Gujrat.
...
PMID:Molecular characterization of beta-thalassemia in Pakistan. 973 Mar 64

Proteins involved in repression of the human beta-globin gene may be useful in the treatment of sickle cell anemia, in conjunction with therapy to reactivate fetal globin genes. If there is a reciprocal elevation of gamma-globin expression upon repression, this approach could be useful in additional hemoglobinopathies. We previously showed that repression of the beta-globin gene appears to be mediated through two DNA sequences, silencers I and II, and identified a protein termed BP1 which binds to both silencer sequences. In this study, we cloned two cDNAs encoding proteins which bind to an oligonucleotide in silencer I containing a BP1 binding site. These cDNAs correspond to HMG-I and HMG-Y, isoforms regarded as architectural proteins. We demonstrate that binding of HMG-I(Y) to this oligonucleotide causes bending/flexure of the DNA. HMG-I(Y) also binds to a second oligonucleotide containing a BP1 binding site located in a negative control region upstream of the delta-globin gene, suggesting a role for HMG-I(Y) in repression of adult globin genes. Expression studies revealed that HMG-I(Y) is ubiquitously expressed in human tissues that do not express beta-globin, being present in 48 of 50 tissues and six hematopoietic cell lines examined. Furthermore, HMG-I(Y) expression is down-regulated during differentiation of primary erythroid cells. We present a model in which HMG-I(Y) alters DNA conformation to allow binding of repressor proteins, and in which the relative amount of HMG-I(Y) helps to determine the repressive state of the beta-globin gene.
...
PMID:Binding of HMG-I(Y) elicits structural changes in a silencer of the human beta-globin gene. 988 3

Retrovirus vectors for A gamma-globin are being developed for the treatment of beta chain hemoglobinopathies. Toward the goal of achieving therapeutic expression levels, core elements of the beta-globin locus control region (LCR) hypersensitive sites (HS) were screened for enhancer activity in erythroid MEL and K562 cell lines using a drug-resistant colony assay. When used alone, core elements of HS1, HS3, and HS4 showed no activity and a fragment for HS2 showed only modest activity in the colony assay. However, a 1.1 kb combination of fragments for HS2, HS3, and HS4 (termed a nLCR) enhanced colony formation 17-fold in K562 cells and 94-fold in MEL cells. Addition of an HS1 fragment enhanced nLCR activity only modestly in MEL cells. When linked to a beta-globin gene, the 1.1 kb nLCR enhanced globin mRNA expression to 82% per copy of mouse alpha-globin in transfected MEL cells. Inclusion of a nLCR in retrovirus vectors containing a beta-globin promoter and various A gamma-globin gene expression cassettes resulted in extreme genetic instability and reduced titers. Specific deletions were abrogated by removing homologous sequences, but random recombinations were still observed at significant frequencies. In MEL cells containing intact provirus, A gamma-globin mRNA produced by an optimal vector containing the nLCR was only 2-fold higher (8.5% vs. 3.9% per copy of mouse alpha-globin) compared to the same vector without the nLCR. These data suggest that vector elements detract from the ability of the nLCR to enhance expression of the beta pr.A gamma cassettes.
...
PMID:Development of a condensed locus control region cassette and testing in retrovirus vectors for A gamma-globin. 1008 91

Progress toward gene therapy of beta-chain hemoglobinopathies has been limited in part by poor expression of globin genes in virus vectors. To derive an optimal expression cassette, we systematically analyzed the sequence requirements and relative strengths of the Agamma- and beta-globin promoters, the activities of various erythroid-specific enhancers, and the importance of flanking and intronic sequences. Expression was analyzed by RNase protection after stable plasmid transfection of the murine erythroleukemia cell line, MEL585. Promoter truncation studies showed that the Agamma-globin promoter could be deleted to -159 without affecting expression, while deleting the beta-globin promoter to -127 actually increased expression compared with longer fragments. Expression from the optimal beta-globin gene promoter was consistently higher than that from the optimal Agamma-globin promoter, regardless of the enhancer used. Enhancers tested included a 2.5-kb composite of the beta-globin locus control region (termed a muLCR), a combination of the HS2 and HS3 core elements of the LCR, and the HS-40 core element of the alpha-globin locus. All three enhancers increased expression from the beta-globin gene to roughly the same extent, while the HS-40 element was notably less effective with the Agamma-globin gene. However, the HS-40 element was able to efficiently enhance expression of a Agamma-globin gene linked to the beta-globin promoter. Inclusion of extended 3' sequences from either the beta-globin or the Agamma-globin genes had no significant effect on expression. A 714-bp internal deletion of Agamma-globin intron 2 unexpectedly increased expression more than twofold. With the combination of a -127 beta-globin promoter, an Agamma-globin gene with the internal deletion of intron 2, and a single copy of the HS-40 enhancer, gamma-globin expression averaged 166% of murine alpha-globin mRNA per copy in six pools and 105% in nine clones. When placed in a retrovirus vector, this cassette was also expressed at high levels in MEL585 cells (averaging 75% of murine alpha-globin mRNA per copy) without reducing virus titers. However, recombined provirus or aberrant splicing was observed in 5 of 12 clones, indicating a significant degree of genetic instability. Taken together, these data demonstrate the development of an optimal expression cassette for gamma-globin capable of efficient expression in a retrovirus vector and form the basis for further refinement of vectors containing this cassette.
...
PMID:Development of viral vectors for gene therapy of beta-chain hemoglobinopathies: optimization of a gamma-globin gene expression cassette. 1009 Sep 29

Hemoglobin S/O(Arab) (Hb S/O(Arab)) is a rare compound heterozygous hemoglobinopathy characterized by the presence of two variant beta-globin chains: beta6Glu --> Val (Hb S) and beta121Glu --> Lys (Hb O(Arab)). The diagnosis of Hb S/O(Arab) requires electrophoresis on both cellulose acetate and citrate agar, since Hb O(Arab) co-migrates with Hb C at alkaline pH and close to Hb S at acidic pH. To date only case reports and small series of patients with Hb S/O(Arab) have been described. To better characterize the clinical and laboratory aspects of this unusual disorder, we reviewed the Duke University Medical Center experience. We identified 13 African-American children and adults with Hb S/O(Arab) ranging in age from 2.7 to 62.5 years. All patients had hemolytic anemia with a median Hb of 8.7 gm/dL (range 6.1-9.9 gm/dL), and a median reticulocyte count of 5.8% (range 1.2-10.3%). The peripheral blood smear typically showed sickled erythrocytes, target cells, polychromasia, and nucleated red blood cells. All 13 patients have had significant clinical sickling events including acute chest syndrome (11), recurrent vasoocclusive painful events (10), dactylitis (7), gallstones (5), nephropathy (4), aplastic crises (2), avascular necrosis (2), leg ulcers (2), cerebrovascular accident (CVA) (1), osteomyelitis (1), and retinopathy (1). Four patients have died, including two from pneumococcal sepsis/meningitis at ages 5 and 10 years, one of acute chest syndrome at age 14 years, and one of multiorgan failure at age 35 years. We conclude that Hb S/O(Arab) disease is a severe sickling hemoglobinopathy with laboratory and clinical manifestations similar to those of homozygous sickle cell anemia.
...
PMID:Hemoglobin S/O(Arab): thirteen new cases and review of the literature. 1020 1


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---