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

The present review summarizes recent cytochemical findings on the functional organization of the nuclear domains, with a particular emphasis on the relation between nuclear envelope-associated proteins and chromatin. Mutations in two nuclear envelope-associated proteins, emerin and lamin A/C cause the Emery-Dreifuss muscular dystrophy; the cellular pathology associated with the disease and the functional role of emerin and lamin A/C in muscle cells are not well established. On the other hand, a large body of evidence indicates that nuclear envelope-associated proteins are involved in tissue-specific gene regulation. Moreover, chromatin remodeling complexes trigger gene expression by utilizing the nuclear matrix-associated actin, which is known to interact with both emerin and lamin A/C. It is thus conceivable that altered expression of these nuclear envelope-associated proteins can account for an impairment of gene expression mainly during cell differentiation as suggested by recent experimental findings on the involvement of emerin in myogenesis. The possibility that Emery-Deifuss muscular dystrophy pathogenesis could involve alteration of the signaling pathway is considered.
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PMID:Immunocytochemistry of nuclear domains and Emery-Dreifuss muscular dystrophy pathophysiology. 1268 53

The human LMNA gene, when mutated, has been shown to cause at least 7 human diseases: dilated cardiomyopathy, Emery Dreifuss muscular dystrophy, limb girdle muscular dystrophy, familial partial lipodystrophy, Charcot Marie tooth disease type II, mandibuloacral dysplasia, and Hutchinson-Gilford Progeria (OMIM #176670). This article describes a high-throughput method for screening the human lamin A/C (LMNA) gene for genetic mutations and sequence variation using denaturing high-performance liquid chromatography (DHPLC). In the present study, 76 patients with dilated cardiomyopathy were screened for mutations using DHPLC and sequence analysis. Abnormal elution profiles were identified and sequenced on an ABI 377 automatic sequencer. Heterozygous LMNA mutations were detected in 8% of the affected patients. In addition, a number of intronic and exonic single nucleotide polymorphisms were identified. LMNA mutations are clinically relevant in at least 6 human diseases. This study provides a protocol for high-throughput LMNA analysis applicable both in the research and in the clinical diagnostic setting.
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PMID:Analysis of genetic variations of lamin A/C gene (LMNA) by denaturing high-performance liquid chromatography. 1547 83

The association between peripheral myopathies and cardiac complications is well established. However, until recently, the clinical and genetic variability of these pathologies limited our ability to recognise individual risk of complications, particularly in the more rare pathologies. Advances have been made in the understanding of the progression, in the physiopathology of molecular deficits and cardiac complications of the different types of muscular dystrophy. This has partially helped to identify the risk of cardiac complications. The commonest condition, Steinert's disease, is associated with a high incidence of atrioventricular block and atrial arrhythmias. Prophylactic implantation of a dual chamber pacemaker with diagnostic functions may be envisaged when the HV interval is greater than 70 ms, on endocavitary electrophysiological investigations. In other patients, follow-up by standard ECG and/or amplified averaged ECG and Holter monitoring is essential. The natural history of Duchenne and Becker muscular dystrophies and the Emery Dreifuss dystrophy have been better described in the last few years. Recommendations have been proposed for the cardiological follow-up of these patients. Empiric recommendations of the same type have been proposed for patients with shoulder and girdle myopathies and propositions for their management have also been made, the pertinence of which is still being evaluated. Our understanding of the incidence, the type, the physiopathology and molecular biology of the various peripheral myopathies and their cardiac complications has advanced considerably in recent years. This has led to the elaboration of new recommendations for diagnostic and therapeutic strategies in these patients.
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PMID:[Conduction defects and arrhythmias in peripheral myopathies]. 1571 87

Emerin is an integral protein of the inner nuclear membrane in the majority of differentiated vertebrate cells. In humans, deficiency of emerin causes a progressive muscular dystrophy of the Emery-Dreifuss type. The physiological role of emerin is poorly understood. By screening and sequencing of EST clones we have identified two emerin homologues in Xenopus laevis, Xemerin1 and Xemerin2. Xemerins share with mammalian emerins the N-terminal LEM domain and a single transmembrane domain at the C-terminus. As shown by immunoblot analysis with Xemerin-specific antibodies, both proteins have an apparent molecular mass of 24 kDa but differ in their isoelectric points. Xemerin1 and Xemerin2 proteins are not detectable in oocytes nor during early embryogenesis. Protein expression is first found at stage 43 and persists in somatic cells. However, RT-PCR and Northern blot analysis show Xemerin mRNAs of approximately 4.0 kb to be present in oocytes and throughout embryogenesis. During embryogenesis the level of Xemerin mRNAs increases at stage 22 and is particularly abundant in mesodermal and neuro-ectodermal regions of the embryo. These data provide the necessary background to further investigate the role of emerin in nuclear envelope assembly, gene expression and organ development of X. laevis as a model organism.
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PMID:Emerin expression in early development of Xenopus laevis. 1581 9

This qualitative study describes conceptions and experiences of the hereditary aspect of muscular dystrophy (MD) from both the patients' and the next of kin's perspective. Different diagnoses of MD are included: dystrophia myotonica, myopathia distalis tarda hereditaria, Becker MD, facioscapulohumeral MD, limb-girdle MD, Emery-Dreifuss and undetermined proximal MD (Duchenne MD is not included). Interviews were conducted with 46 persons with MD and 36 next of kin. The interviews were subjected to inductive content analysis. Only two in each group did not spontaneously mention anything related to the fact that MD is disease with dominant or recessive inheritance. It was found that heredity has a prominent place in the thoughts and feelings of the family. These thoughts were classified as Becoming aware of MD and its hereditary nature, looking into the pedigree, acquiring an understanding of MD, thoughts about genetic testing, interpreting the risk, whether to have children or not, feelings related to the future, and feelings of responsibility and guilt. Families with MD need medical information and the opportunity for genetic testing as well as support and counseling in coming to terms with living with a hereditary disease, whether or not that includes a decision to take a test.
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PMID:Living with a hereditary disease: persons with muscular dystrophy and their next of kin. 1588 11

Laminopathies are a group of diseases due to mutations of type A-lamins, a group of proteins lining the inner aspect of cell nuclei. These diseases illustrate the complexity of the genotype-phenotype relationship characteristic of same genetic diseases. Since the discovery of the causal role of LMNA gene mutations in the genesis of Emery Dreifuss muscular dystrophy in 1999, no less than eight other diseases have been associated with mutations of this same gene! The tissue-specific nature of the clinical manifestations, contrasting with the ubiquitous expression of these proteins, has incited much research concerning the physiological role of lamins, considered to be much broader than the structural function initially put forward. Certain laminopathies, which combine insulin resistance, android distribution of adipose tissue, dyslipidemia, early atherosclerosis, and hepatic steatosis, appear very similar though more severe to the frequent dysmetabolism syndrome. The relationships of laminopathies with accelerated aging syndrome, Hutchinson-Gilford progeria, or progeroid syndromes, which are also related to A/C lamin anomalies, could provide new avenues of research on the pathogenesis of the metabolic syndrome. In addition, clinicians have to be aware of atypical and milder forms of laminopathies, that require specific investigations and molecular screening of relatives allowing an adequate medical management.
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PMID:[Laminopathies: lipodystrophies, insulin resistance, syndromes of accelerated ageing... and others]. 1598 90

The fate of emerin during skeletal muscle regeneration was investigated in an animal model by means of crush injury. Immunofluorescence, immunoblotting and mRNA analysis demonstrated that emerin level is increased in regenerating rat muscle fibers with respect to normal mature myofibers. This finding suggests an involvement of emerin during the muscle fiber regeneration process, in analogy with its reported involvement in muscle cell differentiation in vitro. The impairment of skeletal muscle physiological regeneration or reorganization could be a possible pathogenetic mechanism for Emery Dreifuss muscular dystrophy.
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PMID:Emerin increase in regenerating muscle fibers. 1637 77

Mutations within LMNA, encoding A-type nuclear lamins, are associated with multiple tissue-specific diseases, including Emery-Dreifuss (EDMD2/3) and Limb-Girdle muscular dystrophy (LGMD1B). X-linked EDMD results from mutations in emerin, a lamin A-associated protein. The mechanisms through which these mutations cause muscular dystrophy are not understood. Here we show that most, but not all, cultured muscle cells from lamin A/C knockout mice exhibit impaired differentiation kinetics and reduced differentiation potential. Similarly, normal muscle cells that have been RNA interference (RNAi) down-regulated for either A-type lamins or emerin have impaired differentiation potentials. Replicative myoblasts lacking A-type lamins or emerin also have decreased levels of proteins important for muscle differentiation including pRB, MyoD, desmin, and M-cadherin; up-regulated Myf5; but no changes in Pax3, Pax7, MEF2C, MEF2D, c-met, and beta-catenin. To determine whether impaired myogenesis is linked to reduced MyoD or desmin levels, these proteins were individually expressed in Lmna(-/-) myoblasts that were then induced to undergo myogenesis. Expression of either MyoD or, more surprisingly, desmin in Lmna(-/-) myoblasts resulted in increased differentiation potential. These studies indicate roles for A-type lamins and emerin in myogenic differentiation and also suggest that these effects are at least in part due to decreased endogenous levels of other critical myoblast proteins. The delayed differentiation kinetics and decreased differentiation potential of lamin A/C-deficient and emerin-deficient myoblasts may in part underlie the dystrophic phenotypes observed in patients with EDMD.
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PMID:Lamin A/C and emerin are critical for skeletal muscle satellite cell differentiation. 1648 76

The laminopathies are a diverse group of conditions caused by mutations in the LMNA gene (MIM*150330). LMNA encodes the nuclear envelope proteins lamin A and lamin C by utilization of an alternative splice site in exon 10. The human LMNA gene was identified in 1986 but it was another 13 years before it was found to be the causative gene for a disease, namely Emery Dreifuss muscular dystrophy. Since then, a further eight clearly defined phenotypes have been associated with LMNA mutations. The diversity of these phenotypes is striking with features such as premature ageing, axonal neuropathy, lipodystrophy and myopathy being seen. These phenotypes and the emerging genotype/phenotype correlations are the subject of this review.
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PMID:The laminopathies: a clinical review. 1696 17

Emery Dreifuss muscular dystrophy (EDMD) is an uncommon hereditary myopathy characterized by 3 symptoms: slow progressive muscular atrophy, muscular contractures and cardiac disease which affect prognosis. We report a 22 year-old patient with EDMD which shows the typical features of the associated dilated cardiomyopathy, ventricular arrhythmia, atrio-ventricular block, atrial standstill then atrial paralysis.
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PMID:[Cardiac involvement in Emery-Dreifuss muscular dystrophy: a case report]. 1704 10


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