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Query: UMLS:C0026850 (muscular dystrophy)
 5,870 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Duchenne and the less severe Becker form of muscular dystrophy (DMD,BMD) result from genetic deficiency in the level and/or activity of the protein dystrophin. The recent availability of cDNA based minigenes encoding recombinant dystrophin polypeptides has raised the possibility of somatic gene transfer as a therapeutic approach to treat dystrophin deficiency. In this respect, the mdx mouse provides a useful model of DMD exhibiting features characteristic of both the early myopathic and later fibrotic phases of the human disease. Using a mutated human cDNA, compatible in size with virus-based somatic gene transfer vectors, the pathophysiological consequences of restoring dystrophin expression have been examined in transgenic mdx mice. Transgene expression was correlated with a marked reduction of the skeletal myofibre necrosis and regeneration which is a major feature of the dystrophin-deficient phenotype in young mdx mice. The cDNA construct which is based on a very mild BMD phenotype thus encodes a highly functional dystrophin molecule whose reduced size renders it an attractive candidate for development as a therapeutic gene transfer reagent.
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PMID:Human dystrophin expression corrects the myopathic phenotype in transgenic mdx mice. 130 Nov 34

The rapid progress of research on the structure of the dystrophin gene has enormously increased our understanding of the molecular basis of Duchenne (DMD) and Becker (BMD) muscular dystrophy. Apart from "classical" clinical presentations, asymptomatic or only mildly affected individuals with deletions in the dystrophin gene have now been reported. We describe two families which were initially classified as metabolic myopathies, until the diagnosis of atypical BMD was established after dystrophin analysis at the protein and DNA level. A modern diagnostic approach to myopathies should, therefore, not only include morphological and biochemical investigations, but also be extended to the analysis of the dystrophin gene.
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PMID:Becker muscular dystrophy: detection of unusual disease courses by combined approach to dystrophin analysis. 154 42

We have analyzed patient DNA samples in 77 unrelated Duchenne (DMD) and Becker (BMD) muscular dystrophy families, 73 of which were of French Canadian origin. We show that the frequency (68%) and distribution of deletions within the dystrophin gene was neither random nor unique in this population. We localized 33% of the deletions to the proximal portion of the dystrophin gene while 63% involved the exons spanning introns 43 through 55 with breakpoint clusters occurring within introns 44 and 50. Whether the dystrophin open reading frame (ORF) is maintained constrains the distribution of DMD/BMD deletions such that BMD deletions tend to be strikingly homogeneous. Finally, the conservation of the dystrophin ORF and the severity of the clinical phenotype were concordant in 95% of the DMD/BMD deletions documented by this work.
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PMID:Deletions in the dystrophin gene: analysis of Duchenne and Becker muscular dystrophy patients in Quebec. 161 90

We studied 38 unrelated patients from southern France with Duchenne (DMD) or Becker (BMD) muscular dystrophy for intragenic deletions of the DMD/BMD gene. We used both multiplex amplification of selected exons and cDNA probes. Of the 26 (68%) unrelated individuals found to have deletions, 24 (92%) were detected by multiplex polymerase chain reaction. All these deletions have been delineated with regard to the exon-containing HindIII fragments revealed by cDNA probes, and in two cases, junction fragments of altered size were seen. The correlation between phenotype and type of deletion agreed with the reading frame theory, except for two BMD and two DMD cases.
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PMID:Molecular deletion patterns in families from southern France with Duchenne/Becker muscular dystrophies. 168 65

The localization of the protein dystrophin was studied using the immunofluorescence method, in muscle biopsies from 74 patients affected by different types of muscular dystrophy and 4 normal controls. In 15 patients with limb-girdle muscular dystrophy (LGMD) the pattern was indistinguishable from normal. Among 42 Duchenne patients (DMD), 3 were totally negative and 39 showed a variable proportion (4-30%) of partially labelled fibers. With one exception 17 Becker dystrophy patients (BMD), showed a positive sarcolemmal reaction. A diffuse reaction inside the fibers, which was not observed in normal controls, was seen in the majority of DMD and also in some of the BMD patients. Based on these observations it is suggested that in DMD, a small quantity of protein is still present or there is a cross-reaction with other proteins which share some homology with dystrophin. The present results suggest that it is possible to make a differential diagnosis between DMD and BMD through dystrophin immunohistochemistry. However, to distinguish between patients with BMD and LGMD phenotypes, or DMD and outliers, complementary immunoblot studies and quantitative determination of dystrophin are necessary.
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PMID:Dystrophin immunostaining in muscles from patients with different types of muscular dystrophy: a Brazilian study. 170 Aug 8

Both normal and pathological transcripts of tissue-specific genes may be detected by polymerase chain reaction (PCR) amplification in tissues not normally considered to express the gene product. The exploitation of constitutive basal mRNA levels ("ectopic" transcription) would be a major boon to diagnostic medicine since it promises both to simplify the analysis of complex genes and to avoid the requirement for an expressing tissue that is sometimes obtainable only by biopsy. We have demonstrated the feasibility of this novel strategy by characterizing a mutation in the X-chromosomal Duchenne (or Becker) muscular dystrophy (DMD/BMD) gene encoding dystrophin. The massive size of this gene has in the past often hindered carrier detection due to the high frequency of recombination and the high proportion of new mutations. In this study a deletion was identified in both a BMD patient and a heterozygous carrier using only a minimal volume of peripheral blood. Following specifically primed reverse transcription of lymphocyte RNA, the relevant region of the pathological cDNA was PCR-amplified. Sequence analysis indicated an in-frame deletion of exons 45 to 47.
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PMID:Characterization of pathological dystrophin transcripts from the lymphocytes of a muscular dystrophy carrier. 170 53

Neonatal screening for Duchenne/Becker Muscular dystrophy (DMD/BMD) was begun as a pilot program on January 1, 1986. The aim of this program was to reduce the incidence of this X-linked recessive degenerative neuromuscular disease. The neonatal detection of a boy with DMD allows early identification of carriers and genetic counselling. This may avert the birth of other affected males born prior to clinical diagnosis of DMD in the propositus at about age 5 years. Between January 1, 1986, and December 31, 1988, we identified and characterized a cohort of 8 asymptomatic infant boys with grossly elevated levels of creatine kinase, an active primary dystrophic process of muscle and complete dystrophin deficiency. Five of 8 males have detectable DNA alterations involving the DMD/BMD locus. Based on current hypotheses, characterization of dystrophin expression of this cohort allows us to predict a DMD phenotype in all 8 boys. To date, no additional males with DMD have been born in these families. Prospective follow-up will allow us to test the validity of dystrophin testing in predicting the clinical course and impact of this program on reproductive decision making in these families.
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PMID:Three years' experience with neonatal screening for Duchenne/Becker muscular dystrophy: gene analysis, gene expression, and phenotype prediction. 186 67

Dystrophin is the gene product of the Duchenne (DMD) and Becker (BMD) muscular dystrophy gene locus on the short arm of the X chromosome. Complete lack of dystrophin is pathognomonic for DMD and variable changes of the molecule may be observed in the milder allelic form of BMD. In the present study the two methods available for dystrophin assessment, immunofluorescence detections on cryosections (IF) and Western blotting (WB) were systematically compared using polyclonal and monoclonal antibodies to various regions along the dystrophin molecule. A total of 95 patients with DMD or BMD were investigated including two female patients. Dystrophin assessment revealed abnormal abundance and/or distribution in all 95 patients with DMD or BMD. Only trace amounts of dystrophin were detected in 29% of the DMD patients and complete lack of dystrophin was found in 71%. In two females with DMD but with normal karyotype single dystrophin-positive fibres were found among more than 90% negative fibres. Out of 26 patients with BMD 19 (73%) had a dystrophin molecule of abnormal molecular weight. The results of IF were largely compatible with those from WB but differences were also observed, e.g. one barely symptomatic BMD patient with dystrophin of increased molecular weight showed normal IF. Out of four carriers of BMD three showed evidence of reduced dystrophin immunostaining in some muscle fibres. In 20 other patients limb girdle muscualar dystrophy with "Duchenne-like" or "Becker-like" phenotype was suspected because dystrophin showed normal abundance and distribution. Focal discontinuity of muscle cell-surface dystrophin staining was observed in one patient with a congenital, autosomal recessive muscular dystrophy and in one out of five patients with polymyositis/dermatomyositis. The study emphasizes the need for, and value of, dystrophin assessment in every case of suspected BMD or DMD.
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PMID:Dystrophin as a diagnostic marker in Duchenne and Becker muscular dystrophy. Correlation of immunofluorescence and western blot. 194 22

Duchenne muscular dystrophy (DMD) is a fatal X-linked recessive disorder of muscle in children, with an incidence of approximately 1 in 3,300 male births. In about a third of affected boys, the disease is due to a new mutation, and most patients die in their early 20s. Over the last few years, the genetic, biochemical and histopathological basis of DMD has been elucidated greatly. In particular, the discovery of "dystrophin," the protein product of the DMD gene is truly an epoch-making success in the history of muscular dystrophy research. Dystrophin is now thought to be a cytoskeletal protein underlying the plasma membrane (known in muscle as the sarcolemma) of normal muscle fiber, and is undetectable or greatly reduced in DMD. In this review article, dystrophin in normal skeletal muscle and various neuromuscular diseases including DMD/BMD (Becker muscular dystrophy), and its carrier is discussed.
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PMID:Dystrophin abnormality in progressive muscular dystrophy--a review article. 195 48

The gene for Duchenne (DMD) and Becker (BMD) types of muscular dystrophy has been isolated by Kunkel's and Worton's groups and shown to be the largest one over known in human, spanning more than 65 exons distributed over 2,500 kb in P21 region of X-chromosome. Fourteen kb cDNA encodes 427 kD cytoskeletal protein "dystrophin", supposed to form an anti-parallel homodimer like alpha-actinin and spectrin. The polyclonal antibodies against the synthetic peptides or fusion proteins predicted from dystrophin cDNA disclosed the complete absence of dystrophin at the surface membrane of both skeletal and cardiac muscles of DMD in marked contrast with the continuous and uniform staining in normal muscles. In manifested carriers, the mosaic expression of dystrophin was observed at the surface membrane of the skeletal muscle. BMD, which is thought to be allelic to DMD, revealed a faint or patchy immunostaining along with the abnormal and/or lower amount of dystrophin. In BMD, there is an intimate connection between the amount of dystrophin and the severity of the clinical course. It should be noted that 5 out of 39 patients with clinical diagnosis of limb-girdle (L-G) muscular dystrophy showed a patchy staining pattern, suggesting BMD not L-G. On the basis of dystrophin discovery, a possible therapeutic trial of DMD is discussed.
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PMID:[Molecular pathology of Duchenne and Becker muscular dystrophy]. 209 74


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