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Query: UMLS:C0002895 (sickle cell disease)
 11,747 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Although DNA analysis based on the polymerase chain reaction (PCR) offers potential advantages for screening newborns for sickle cell disease, few data are available concerning the reliability of PCR-based tests for such screening. We describe a protocol for detecting the A, S, and C alleles of the beta-globin gene in dried blood from phenylketonuria screening cards. This method is based on PCR and detection with allele-specific oligonucleotide probes. Results of a blind comparison of PCR analysis of the dried blood with hemoglobin electrophoresis of whole-blood samples agreed for 80 of 81 samples. The single discrepancy is probably not attributable to a failure of the PCR method, but rather to limitations of the electrophoresis method. The PCR method should be a highly accurate means of detecting beta-globin alleles in routine genetic screening with dried blood already collected for (e.g.) phenylketonuria screening.
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PMID:Genetic screening of newborns for sickle cell disease: correlation of DNA analysis with hemoglobin electrophoresis. 200 56

A single base-pair mutation (beta s) in codon 6 of the human beta-globin gene, causing a single amino-acid substitution, is the cause of sickle cell anaemia. The mutant haemoglobin molecule, HbS, polymerizes when deoxygenated and causes deformation of the erythrocytes to a characteristic 'sickled' shape. Sickling of cells in small vessels causes painful crises and other life-threatening complications. Although the molecular basis for sickle cell anaemia has been known for 30 years, no definitive treatment is available. An animal model of sickle cell anaemia would not only allow a detailed analysis of the factors that initiate erythrocyte sickling in vivo and of the pathophysiology of the disease, but would also permit the development of novel approaches to the treatment of the disease. By using the dominant control region sequences from the human beta-globin locus, together with human alpha- and beta s-globin genes, we have obtained three transgenic mice with HbS levels ranging from 10 to 80% of total haemoglobin in their red cells. As observed in homozygous and heterozygous Hbs patients, the erythrocytes of this mouse sickle readily on deoxygenation. Irreversibly sickled cells, which are characteristic of sickle-cell patients homozygous for beta s, are also observed in the peripheral blood of the mouse with high levels of HbS.
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PMID:A transgenic mouse model of sickle cell disorder. 229 3

Ten patients with sickle cell (SS) disease from a Jamaican family were found to have unusually high levels of haemoglobin F for this population. Each of them has inherited one sickle cell gene on a chromosome characterized by an arrangement of restriction fragment length polymorphisms (haplotype) which is very rare in the Jamaican population. Genetic analysis of the family suggests that there is a determinant linked to the beta-globin gene cluster, characterized by this haplotype, which is responsible for increased haemoglobin F production in response to anaemia. Interestingly this particular haplotype appears to be common in patients with SS disease in eastern Saudi Arabia in whom a high level of haemoglobin F is the rule rather than the exception. Hence it is possible that this haplotype (++-++) acts as a genetic marker for elevated levels of haemoglobin F in sickle cell disease.
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PMID:A genetic marker for elevated levels of haemoglobin F in homozygous sickle cell disease? 240 56

Homozygous sickle cell disease in the eastern province of Saudi Arabia is clinically mild. Circulating fetal hemoglobin levels of 16.0 +/- 7.4% were found in these anemic patients, but only 1.09 +/- 0.97% in their sickle trait parents. To determine whether these sickle cell anemia patients inherit an increased capacity to synthesize fetal hemoglobin, a radioimmunoassay of fetal and adult hemoglobin was performed on erythroid progenitor (BFU-E)-derived erythroblasts from Saudi Arabian sickle cell patients and their parents. Mean fetal hemoglobin content per BFU-E-derived erythroblast from Saudi Arabian sickle cell patients was 6.2 +/- 2.4 pg/cell or 30.4 +/- 8.6% fetal hemoglobin (normal 1.1 +/- 0.7 pg/cell and 5.1 +/- 1.8%). Linear regression analysis of % HbF in peripheral blood versus % HbF per BFU-E-derived cell showed a positive correlation with an r of 0.65. The variance of the intrinsic capacity to produce HbF may account for almost 40% (r2) of the variance of circulating fetal hemoglobin but other factors, particularly selective survival of F cells, must also contribute significantly. Despite virtually normal HbF levels in sickle trait parents of these Saudi patients, mean fetal hemoglobin production per BFU-E-derived erythroblast in these individuals was elevated to 3.42 +/- 1.79 pg/cell or 16.1 +/- 6.4% fetal hemoglobin, and the magnitude of fetal hemoglobin production found in parents correlated with that of the patients. These data indicate that the high fetal hemoglobin in Saudi sickle cell disease is genetically determined but expressed only during accelerated erythropoiesis. Further evidence of such genetic determination was provided by analysis of DNA polymorphisms within the beta-globin gene cluster on chromosome 11. This revealed a distinctive 5' globin haplotype (+ + - + +) on at least one chromosome 11 in all high F SS and AS tested. The precise relationship of this haplotype to HbF production in this population remains to be defined.
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PMID:High fetal hemoglobin production in sickle cell anemia in the eastern province of Saudi Arabia is genetically determined. 242 8

We linked a 3.3-kilobase fragment containing the entire A gamma-globin gene together with 1.3 kilobases of 5' flanking and 0.37 kilobase of 3' flanking DNA to a 2.5-kilobase fragment containing four of the developmentally stable hypersensitive sites normally located in the 5' region of the human beta-globin locus. This construct was injected into fertilized mouse eggs, and its expression was analyzed in the primitive and definitive erythroid cells, as well as the brain of 14-day embryos. All six transgenic individuals that contained intact copies of the construct expressed the transgene in an erythroid-specific fashion. Expression was observed in both primitive and definitive erythroid cells. This is in marked contrast to previous transgenic mice experiments using the same A gamma-globin gene fragment in isolation, where expression was restricted to primitive erythroid cells. Our results show that the region containing the developmentally stable globin locus hypersensitive sites changes the developmental stage specificity of a human fetal globin gene in transgenic mice. These observations imply that sequences additional to those used here are involved in the developmental control of fetal globin gene expression in vivo. The ability to express fetal globin in adult erythroid cells allows one to consider using fetal globin genes for gene therapy of sickle cell disease.
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PMID:The human beta-globin locus activation region alters the developmental fate of a human fetal globin gene in transgenic mice. 247 9

Restriction endonuclease analysis of DNA was undertaken in blood samples from individuals who were normal (110), had sickle cell trait (44) and homozygous sickle cell disease (6) from the tribal populations of Bihar, Madhya Pradesh, Gujarat and southern Rajasthan. DNA was prepared from all the blood samples and processed for restriction enzyme digestion, agarose electrophoresis, prehybridization, Nick-translation hybridization and autoradiography. A polymorphic HpaI restriction endonuclease recognition site on the 3' side of the beta-globin gene was used to analyse to determine the beta-globin gene mutant S. It was found that mutation has resulted within the normal 7.6 Kb HpaI fragment among the tribal populations studied. On comparing the results with those from Middle East and East Africa it appears that the sickle gene mutation in India, Saudi Arabia and Kenya arose separately from that in West Africa.
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PMID:Restriction endonuclease analysis of DNA in sickle cell lesions among tribals of Bihar, Madhya Pradesh, Gujarat & Rajasthan. 257 21

Patients with sickle cell anemia vary in the hematologic and clinical features of their disease, in part because of variability in the presence of linked and unlinked genes that modify the expression of the disease. The hemoglobin S gene is strongly linked to three different haplotypes of polymorphic endonuclease-restriction sites of the beta-like gene cluster (genes in the vicinity of the beta-globin gene)--one prevalent in Atlantic West Africa, another in central West Africa, and yet another in Bantu-speaking Africa (equatorial, East, and southern Africa). We have studied the differences in the hematologic characteristics of patients with sickle cell anemia from the first two geographical areas. We find that the Senegalese (Atlantic West Africa) patients have higher levels of hemoglobin F, a preponderance of G gamma chains in hemoglobin F, a lower proportion of very dense red cells, and a lower percentage of irreversibly sickled cells than those from Benin (central West Africa). We interpret these data to mean that the gamma-chain composition and the hemoglobin F level are haplotype linked and that the decrease in the percentage of dense cells and irreversibly sickled cells is secondary to the elevation in the hemoglobin F level. Patients with sickle cell anemia in the New World probably correspond to various combinations of these types, in addition to the still hematologically undefined haplotype associated with sickle cell anemia in the Bantu-speaking areas of Africa.
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PMID:Hematologically and genetically distinct forms of sickle cell anemia in Africa. The Senegal type and the Benin type. 257 36

The current status of gene transfer experiments indicates that it is possible to provide (1) safe and efficient retroviral packaging lines for gene transfer; and (2) vectors containing the human beta-globin genes and selectable marker genes which can be transmitted into erythroid cells and are appropriately expressed. In animal autologous bone marrow transplantation experiments, stable and high-level expression of retroviral vectors containing human beta-globin genes has not yet been achieved. New retroviral vectors are being tested that contain different components of the retrovirus as well as the newly described enhancer elements 5' to the epsilon gene and surrounding the beta-globin gene. The long-term goal of human gene therapy for sickle cell disease then consists of constructing optimally safe and efficient retroviral packaging lines as well as retroviral vectors containing the human beta-globin gene and selectable markers such as the neoR gene. One would then remove bone marrow cells from patients with sickle cell disease, transfer the retroviral vectors into the bone marrow cells, and subject the cells to G418 selection in vitro. Next, one would ablate the host bone marrow and autotransplant the manipulated bone marrow bearing the retroviral vector. Finally, one would analyze the reconstituted bone marrow for human beta-globin gene expression. These experiments must await the demonstration of safe and efficient gene transfer in animals, and particularly experiments must be done in monkeys prior to the use of these approaches in humans. Alternative approaches to gene therapy include direct correction of the defect in the beta-globin gene by site-specific recombination of the defective gene with incoming normal gene sequences. This technology is not yet achievable, although preliminary experiments have been performed in which gene correction at a low frequency has been obtained. The obvious advantage of this approach is that the native human beta gene would be reconstituted. Site-specific recombination and addition of normal beta genes to the human genome represent exciting and feasible approaches to human gene therapy using the extraordinary resources of modern molecular and cellular biology. Success in treating disorders of human hemoglobin only awaits additional technical advances for increasing the efficiency of gene transfer and the level of gene expression.
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PMID:Gene transfer. A potential approach to gene therapy for sickle cell disease. 267 70

The protein-based technologies used to screen newborns for sickle cell disease require confirmation with a liquid blood specimen. We have developed a strategy for rapid and specific genotypic diagnosis using DNA extracted from a dried blood spot on the filter paper blotter used to screen newborns. DNA could be microextracted from a specimen as small as a 1/8 inch diameter punched disc representing the dried equivalent of approximately 3 microliters of whole blood. We utilized the DNA from a 1/4 inch diameter specimen (12 microliters equivalent) for polymerase chain reaction amplification of the beta-globin region spanning the sickle cell mutation with detection by allele-specific oligonucleotide probes. Molecular confirmation of genotype from the original blotter would reduce the personnel costs associated with obtaining follow-up liquid blood specimens and would provide information to the family in a more timely and less equivocal manner.
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PMID:Molecular genetic diagnosis of sickle cell disease using dried blood specimens on blotters used for newborn screening. 270 39

DNA samples from numerous subjects of different racial and ethnic backgrounds, with or without various hemoglobinopathies (classical beta-thalassemia; silent beta-thalassemia, Hb E, sickle cell anemia), were studied for a rearrangement (+ATA; -T) at nucleotide -530 in the 5' flanking region of the beta-globin gene using amplified DNA and 32P-labeled synthetic oligonucleotide probes. The data show that this unusual sequence is a common feature among East-Asians and Blacks (particularly SS patients), and is not associated with mild thalassemic features typical for the silent form of beta-thalassemia, as has been suggested (5).
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PMID:High frequencies of a rearrangement (+ATA; -T) at -530 to the beta-globin gene in different populations indicate the absence of a correlation with a silent beta-thalassemia determinant. 270 62


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