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Wang S, Peng D. Cardiac Involvement in Emery-Dreifuss Muscular Dystrophy and Related Management Strategies. Int Heart J 2018; 60:12-18. [PMID: 30518714 DOI: 10.1536/ihj.17-604] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is a group of hereditary muscular dystrophy syndrome caused by deficiency of genes encoding nuclear envelope proteins. Patients having EDMD show the triad of muscle dystrophy, joint contracture, and cardiac disease. In almost all patients, cardiac involvement is prevalent and is the most severe aspect of EDMD. Cardiac disease is predominantly shown by conduction defects, atrial fibrillation/flutter, and atrial standstill. Sudden death and heart failure because of left ventricular dysfunction are important causes of mortality, particularly in those patients that have the LMNA mutation. Medical treatment of EDMD is limited to addressing symptoms and ambulation support; moreover, pacemaker implantation is necessary when there are severe conduction defects and bradycardia occurs. Note that automated defibrillation devices may be considered for those patients who have a high risk of sudden death, rate, or rhythm control. Also, anticoagulation should be initiated in those patients who have atrial fibrillation/flutter. Thus, for optimal management, a multidisciplinary approach is required.
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Affiliation(s)
- Shuai Wang
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University
| | - Daoquan Peng
- Department of Cardiovascular Medicine, Second Xiangya Hospital of Central South University
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2
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Eymard B, Ferreiro A, Ben Yaou R, Stojkovic T. Muscle diseases with prominent joint contractures: Main entities and diagnostic strategy. Rev Neurol (Paris) 2013; 169:546-63. [DOI: 10.1016/j.neurol.2013.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 01/13/2023]
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3
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Barresi R. From proteins to genes: immunoanalysis in the diagnosis of muscular dystrophies. Skelet Muscle 2011; 1:24. [PMID: 21798100 PMCID: PMC3156647 DOI: 10.1186/2044-5040-1-24] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 06/24/2011] [Indexed: 12/23/2022] Open
Abstract
Muscular dystrophies are a large heterogeneous group of inherited diseases that cause progressive muscle weakness and permanent muscle damage. Very few muscular dystrophies show sufficient specific clinical features to allow a definite diagnosis. Because of the currently limited capacity to screen for numerous genes simultaneously, muscle biopsy is a time and cost-effective test for many of these disorders. Protein analysis interpreted in correlation with the clinical phenotype is a useful way of directing genetic testing in many types of muscular dystrophies. Immunohistochemistry and western blot are complementary techniques used to gather quantitative and qualitative information on the expression of proteins involved in this group of diseases. Immunoanalysis has a major diagnostic application mostly in recessive conditions where the absence of labelling for a particular protein is likely to indicate a defect in that gene. However, abnormalities in protein expression can vary from absence to very subtle reduction. It is good practice to test muscle biopsies with antibodies for several proteins simultaneously and to interpret the results in context. Indeed, there is a degree of direct or functional association between many of these proteins that is reflected by the presence of specific secondary abnormalities that are of value, especially when the diagnosis is not straightforward.
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Affiliation(s)
- Rita Barresi
- NCG Diagnostic & Advisory Service for Rare Neuromuscular Diseases, Muscle Immunoanalysis Unit, Dental Hospital, Richardson Road, Newcastle upon Tyne, UK.
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4
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Abstract
AbstractType 1 myotonic dystrophy (DM1) is an autosomal dominant disorder caused by a CTG repeat expansion. RNA containing expanded CUG repeats does not leave the nucleus, but accumulates in discrete nuclear foci which sequester the human muscleblind-like (MBNL) proteins. We have examined buccal cells from 15 adult DM1 patients and 7 control non-DM patients to determine whether nuclear foci can be detected by either immunostaining for MBNL1 protein or fluorescent in situ hybridisation (FISH) for the CUG repeat RNA. Both methods detected nuclear foci in all three early-onset patients, but only in a minority of 12 less severe DM1 patients. There were no false-positive results in the 7 controls. Although the method does not reliably identify all DM1 patients, it may prove useful as a rapid test for severe congenital DM1 in floppy babies.
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Abstract
EDMD (Emery–Dreifuss muscular dystrophy) is caused by mutations in either the gene encoding for lamin A/C (LMNA) located at 1q21.2–q21.3 or emerin (EMD) located at Xq28. Autosomal dominant EDMD caused by LMNA mutations is more common than the X-linked form and often more severe, with an earlier onset. At the histological and histochemical levels, both X-linked and autosomal dominant EDMD appear similar. However, individuals with the same genetic disorder often show remarkable differences in clinical severity, a finding generally attributed to the genetic background. The clinical and pathological findings in EDMD patients found to have mutations in more than one gene are also discussed. There is now much interest in the phenotype of several animal models for EDMD which should lead to an increased insight into the pathogenesis of this disorder, particularly that relating to the heart phenotype.
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MOHLER PETERJ, ANDERSON MARKE. New Insights into Genetic Causes of Sinus Node Disease and Atrial Fibrillation. J Cardiovasc Electrophysiol 2008; 19:516-8. [DOI: 10.1111/j.1540-8167.2007.01097.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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7
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Cardoso SV, Moreti MM, Costa IM, Loyola AM. Exfoliative cytology: a helpful tool for the diagnosis of paracoccidioidomycosis. Oral Dis 2008. [DOI: 10.1034/j.1601-0825.2001.70403.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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8
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Lattanzi G, Ognibene A, Sabatelli P, Capanni C, Columbaro M, Santi S, Riccio M, Merlini L, Maraldi N, Squarzoni S, Toniolo D. Emerin expression at the early stages of myogenic differentiation. Differentiation 2008. [DOI: 10.1111/j.1432-0436.2000.660407.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Karst ML, Herron KJ, Olson TM. X-linked nonsyndromic sinus node dysfunction and atrial fibrillation caused by emerin mutation. J Cardiovasc Electrophysiol 2008; 19:510-5. [PMID: 18266676 DOI: 10.1111/j.1540-8167.2007.01081.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
INTRODUCTION Atrial fibrillation (AF) is a heritable disorder with male predilection, suggesting a sex chromosome defect in certain patients. Loss-of-function truncation mutations in EMD, encoding the nuclear membrane protein emerin, cause X-linked Emery-Dreifuss muscular dystrophy (EDMD) characterized by localized contractures and skeletal myopathy in adolescence, sinus node dysfunction (SND) in early adulthood, and atrial fibrillation as a variably associated trait. This study sought to identify the genetic basis for male-restricted, nonsyndromic sinus node dysfunction and AF in a multigenerational family. METHODS AND RESULTS Genealogical and medical records, and DNA samples, were obtained. Progressive SND and AF occurred in four males related through maternal lineages, consistent with X-linked inheritance. Skeletal myopathy was absent, even at advanced ages. Targeted X chromosome genotyping mapped the disease locus to Xq28, implicating EMD as a positional candidate gene. DNA sequencing revealed hemizygosity for an in-frame 3-bp deletion in EMD (Lys37del) in affected males, disrupting a residue within the LEM binding domain critical for nuclear assembly but leaving the remainder of the protein intact. Buccal epithelial cell staining with emerin antibody demonstrated near-total functional loss of emerin. Female relatives underwent prospective electrocardiographic and genetic testing. Those heterozygous for Lys37del had approximately 50-70% emerin-positive nuclei and variable degrees of paroxysmal supraventricular arrhythmia. CONCLUSIONS Mutation of EMD can underlie X-linked familial AF. Lys37del is associated with epithelial cell emerin deficiency, as in EDMD, yet it causes electrical atriomyopathy in the absence of skeletal muscle disease. Targeted genetic testing of EMD should be considered in patients with SND-associated AF and/or family history suggesting X-linked inheritance.
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Affiliation(s)
- Margaret L Karst
- Department of Medicine, Division of Cardiovascular Diseases, and Pediatric and Adolescent Medicine, College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA
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10
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Abstract
The muscular dystrophies are characterised by progressive muscle weakness and wasting. Pathologically the hallmarks are muscle fibre degeneration and fibrosis. Several recessive forms of muscular dystrophy are caused by defects in proteins localised to the sarcolemma. However, it is now apparent that others are due to defects in a wide range of proteins including those which are either nuclear-related (Emery-Dreifuss type muscular dystrophies, oculopharyngeal muscular dystrophy), enzymatic (limb-girdle muscular dystrophy 2A, myotonic dystrophy) or sarcomeric (limb-girdle muscular dystrophies 1A and 2G). Although the clinical and molecular basis of these disorders is heterogeneous all display myopathic morphological features. These include variation in fibre size, an increase in internal nuclei, and some myofibrillar distortion. Degeneration and fibrosis occur, but usually not to the same extent as in muscular dystrophies associated with sarcolemmal protein defects. This review outlines the genetic basis of these "non-sarcolemmal" forms of dystrophy and discusses current ideas on their pathogenesis.
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Affiliation(s)
- S C Brown
- Dubowitz Neuromuscular Centre, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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Abstract
Most neuromuscular disorders display only non-specific myopathological features in routine histological preparations. However, a number of proteins, including sarcolemmal, sarcomeric, and nuclear proteins as well as enzymes with defects responsible for neuromuscular disorders, have been identified during the past two decades, allowing a more specific and firm diagnosis of muscle diseases. Identification of protein defects relies predominantly on immunohistochemical preparations and on Western blot analysis. While immunohistochemistry is very useful in identifying abnormal expression of primary protein abnormalities in recessive conditions, it is less helpful in detecting primary defects in dominantly inherited disorders. Abnormal immunohistochemical expression patterns can be confirmed by Western blot analysis which may also be informative in dominant disorders, although its role has yet to be established. Besides identification of specific protein defects, immunohistochemistry is also helpful in the differentiation of inflammatory myopathies by subtyping cellular infiltrates and demonstrating up-regulation of subtle immunological parameters such as cell adhesion molecules. The role of immunohistochemistry in denervating disorders, however, remains controversial in the absence of a reliable marker of muscle fibre denervation. Nevertheless, as well as the diagnostic value of immunocytochemical analysis it may also widen understanding of muscle fibre pathology as well as help in the development of therapeutic strategies.
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Affiliation(s)
- D S Tews
- Edinger-Institute of the Johann-Wolfgang Goethe-University, Frankfurt, Germany.
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Abstract
The diagnostic muscle biopsy has seen the use of virtually every histologic technique in existence over the past 50 years. Since the 1960s, enzyme histochemistry has become the chief technique in evaluating muscle biopsies. However, the increasing knowledge of cellular constituents and associated connective tissue of the myofiber coupled with the increasing availability of a broad diversity of antibodies to these proteins promises to bring the diagnosis of muscle disease to the same state of dependency upon immunohistochemistry as in the contemporary pathologic diagnosis of neoplasia. Immunohistochemistry may be used for both the identification of normal antigenic constituents in skeletal muscle and their loss, accumulation, or maldistribution in corresponding myopathies, sometimes with small biopsies or lacking frozen tissue, in paraffin sections. Three broad categories of muscle diseases will be characterized in terms of diagnostic antibodies in current use: dystrophic, congenital/structural, and inflammatory myopathies.
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Affiliation(s)
- Hannes Vogel
- Department of Pathology, Stanford University School of Medicine, Palo Alto, CA 94305, USA.
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Vytopil M, Vohanka S, Vlasinova J, Toman J, Novak M, Toniolo D, Ricotti R, Lukas Z. The screening for X-linked Emery-Dreifuss muscular dystrophy amongst young patients with idiopathic heart conduction system disease treated by a pacemaker implant. Eur J Neurol 2004; 11:531-4. [PMID: 15272897 DOI: 10.1111/j.1468-1331.2004.00825.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The X-linked Emery-Dreifuss muscular dystrophy (X-EDMD) is a hereditary muscle disorder associated with cardiac involvement. Sinus node dysfunction and atrioventricular conduction defects, typical of X-EDMD, occur in both males and females and may result in sudden cardiac death unless treated by permanent pacing. The objective of the study was to determine the frequency and relevance of X-EDMD in heart conduction system disease in young individuals treated with a pacemaker implant. The medical history of 3450 paced individuals in the region of South Moravia, Czech republic, was reviewed. Thirty-five patients, 20 males and 15 females, with idiopathic heart conduction disease of onset before age 40 were identified and screened for X-EDMD. Within these 35 individuals, only one male was found to carry a mutation in X-EDMD gene. We conclude that the clinical relevance of X-EDMD in heart conduction system disease is very low. It should, however, be included into the diagnostic work-up of young male individuals with idiopathic cardiac conduction disturbances.
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Affiliation(s)
- M Vytopil
- Department of Neurology, University Hospital Brno, Czech Republic.
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14
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Abstract
Nuclear muscular dystrophies are referred to as inherited muscular dystrophies caused by mutations in genes--(STA) or lamina (LMNA)--encoding components of the nuclear envelope. Phenotypically, they present as Emery-Dreifuss muscular dystrophy (EDMD), limb-girdle muscle dystrophy 1B (LGMD1B), or dilated cardiomyopathy with conduction defects (DCM-CD). Genetically related are the Dunnigan-type of familial partial lipodystrophy (FPLD) and Charcot-Marie-Tooth neuropathy type 2 (CMT2B). Until now, approximately 70 unique STA mutations, leading to X-linked EDMD or DCM-CD, have resulted mostly in a complete lack of emerin. Further 50 mostly missense mutations in LMNA result in autosomal-dominant EDMD, autosomal-recessive EDMD, LGMD1B, DCM-CD, FPLD, or CMT2B. Independent of type or location of the mutations, emerinopathies and laminopathies show wide clinical intrafamilial and interfamilial variability. Although structural abnormalities of nuclei in animal and cell models have been observed, the molecular pathology of the nuclear muscular dystrophies needs still to be elucidated.
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15
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Helbling-Leclerc A, Bonne G, Schwartz K. Emery-Dreifuss muscular dystrophy. Eur J Hum Genet 2002; 10:157-61. [PMID: 11973618 DOI: 10.1038/sj.ejhg.5200744] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2001] [Revised: 09/05/2001] [Accepted: 09/07/2001] [Indexed: 11/08/2022] Open
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is characterised by early contractures, slowly progressive muscle wasting and weakness with a distinctive humero-peroneal distribution and cardiac conduction defects leading to dilated cardiomyopathy. The genes known to be responsible for EDMD encode proteins associated with the nuclear envelope: the emerin and the lamins A and C.
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Colomer J, Iturriaga C, Bonne G, Schwartz K, Manilal S, Morris GE, Puche M, Fernández-Alvarez E. Autosomal dominant Emery-Dreifuss muscular dystrophy: a new family with late diagnosis. Neuromuscul Disord 2002; 12:19-25. [PMID: 11731280 DOI: 10.1016/s0960-8966(01)00239-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Emery-Dreifuss muscular dystrophy is characterized by the clinical triad of early onset contractures of elbows, Achilles tendons and spine, wasting and weakness with a predominantly humero-peroneal distribution and life-threatening cardiac conduction defects and/or cardiomyopathy. Two main types of inheritance have been described: the X-linked form is caused by mutations in the STA gene on locus Xq28 and the gene for the autosomal dominant form (LMNA gene) has been localized on chromosome 1q11-q23. Recently, mutations in this LMNA gene have been also found to be responsible for the less frequent autosomal recessive form of the disease. Although all forms share a similar clinical presentation, some differences appear to exist between them as has been described recently in a large number of patients. We present the first documented Spanish family genetically confirmed to have autosomal dominant Emery-Dreifuss muscular dystrophy. Clinical, pathological and genetic data are described. We emphasize the difficulties in diagnosis, especially in sporadic cases or young patients in whom the clinical picture is not completely established.
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Affiliation(s)
- J Colomer
- Servei de Neurologia, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu, 2, 08950 Esplugues, Barcelona, Spain.
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Lattanzi G, Ognibene A, Sabatelli P, Capanni C, Toniolo D, Columbaro M, Santi S, Riccio M, Merlini L, Maraldi NM, Squarzoni S. Emerin expression at the early stages of myogenic differentiation. Differentiation 2000; 66:208-17. [PMID: 11269947 DOI: 10.1046/j.1432-0436.2000.660407.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Emerin is an ubiquitous protein localized at the nuclear membrane of most cell types including muscle cells. The protein is absent in most patients affected by the X-linked form of Emery-Dreifuss muscular dystrophy, a disease characterized by slowly progressive muscle wasting and weakness, early contractures of the elbows, Achilles tendons, and post-cervical muscles, and cardiomyopathy. Besides the nuclear localization, emerin cytoplasmic distribution has been suggested in several cell types. We studied the expression and the subcellular distribution of emerin in mouse cultured C2C12 myoblasts and in primary cultures of human myoblasts induced to differentiate or spontaneously differentiating in the culture medium. In differentiating myoblasts transiently transfected with a cDNA encoding the complete emerin sequence, the protein localized at the nuclear rim of all transfected cells and also in the cytoplasm of some myoblasts and myotubes. Cytoplasmic emerin was also observed in detergent-treated myotubes, as determined by electron microscopy observation. Both immunofluorescence and biochemical analysis showed, that upon differentiation of C2C12 cells, emerin expression was decreased in the resting myoblasts but the protein was highly represented in the developing myotubes at the early stage of cell fusion. Labeling with specific markers of myogenesis such as troponin-T and myogenin permitted the correlation of increased emerin expression with the onset of muscle differentiation. These data suggest a role for emerin during proliferation of activated satellite cells and at the early stages of differentiation.
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Affiliation(s)
- G Lattanzi
- Istituto di Citomorfologia Normale e Patologica CNR, Via di Barbiano 1/10 40136 Bologna, Italy.
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Abstract
There is a growing body of evidence in favour of the presence of human diseases caused by mutations in genes that encode the nuclear envelope proteins emerin and lamin A/C (lamin A and C are alternatively spliced variants of the same gene). Emerin deficiency results in X-linked Emery-Dreifuss muscular dystrophy (EDMD). Lamin A/C mutations cause the autosomal-dominant form of EDMD, limb-girdle muscular dystrophy with atrioventricular conduction disturbances (type 1B), hypertrophic cardiomyopathy and Dunnigan-type familial partial lipodystrophy. In the targeted mouse model of lamin A gene deficiency, loss of lamin A/C is associated with mislocalization of emerin. Thus, one plausible pathomechanism for EDMD, limb-girdle muscular dystrophy type 1B, hypertrophic cardiomyopathy and familial partial lipodystrophy is the presence of specific abnormalities of the nuclear envelope. Therefore, a group of markedly heterogeneous disorders can be classified as 'nuclear envelopathies'. The present review summarizes recent findings on nuclear envelope proteins and diseases.
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Affiliation(s)
- A Nagano
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry, Tokyo, Japan
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19
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Abstract
Emery-Dreifuss muscular dystrophy (EDMD) was delineated as a separate form of muscular dystrophy nearly 40 years ago, based on the distinctive clinical features of early contractures and humero-peroneal weakness, and cardiac conduction defects. The gene, STA at Xq28, for the commoner X-linked EDMD encodes a 34 kD nuclear membrane protein designated 'emerin', and in almost all cases on immunostaining is absent in muscle, skin fibroblasts, leucocytes and even exfoliative buccal cells, and a mosaic pattern in female carriers. The gene, LMNA at 1q21, for the autosomal dominant Emery-Dreifuss muscular dystrophy encodes other nuclear membrane proteins, lamins A/C. The diagnosis (at present) depends on mutation analysis rather than protein immunohistochemistry. It is still not at all clear how defects in these nuclear membrane proteins are related to the phenotype, even less clear that LMNA mutations can also be associated with familial dilated cardiomyopathy with no weakness, and even familial partial lipodystrophy with diabetes mellitus and coronary heart disease! What began as clinical studies in a relatively rare form of dystrophy has progressed to detailed research into the functions of nuclear membrane proteins particularly in regard to various forms of heart disease.
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Affiliation(s)
- A E Emery
- Department of Neurology, Royal Devon & Exeter Hospital, EX2 5DW, Exeter, UK
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Abstract
Immunocytochemistry is an essential tool for the assessment of muscle biopsies from patients with muscular dystrophy, especially the recessive forms. Antibodies can detect primary defects when there is an alteration in expression, in particular in Xp21 muscular dystrophies, Emery-Dreifuss muscular dystrophy, the limb-girdle dystrophies caused by abnormal expression of the sarcoglycans, and in the form of congenital muscular dystrophy linked to the gene for laminin alpha2. Absence of a protein is easily observed and reduction in expression can be assessed provided adequate controls and baselines are established. Assessment of secondary defects can also be of diagnostic value; they widen the understanding of pathology changes, and are helping in the development of therapeutic strategies.
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Affiliation(s)
- C A Sewry
- Dubowitz Neuromuscular Centre, Department of Paediatrics and Neonatal Medicine, Imperial College School of Medicine, Hammersmith Hospital, London, United Kingdom W12 ONN.
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21
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Abstract
Emerin encoded by the STA gene is the first nuclear protein linked with a muscular dystrophy. Emerin is a 34 kDa, predominantly hydrophilic protein with a single hydrophobic region supposed to serve as a transmembrane domain. It was classified as a type II integral membrane protein localized at the inner nuclear membrane/nuclear lamina with an ubiquitous tissue distribution. It is speculated that emerin is required for the stability and normal function of rigorously moving nuclei in skeletal muscle and heart. During mitosis, emerin is cell-cycle-dependent phosphorylated and shows stage-dependent changes in distribution and localization suggesting that it plays a role in re-assembly of nuclear membranes. Mutations of the emerin gene have been associated with X-linked Emery-Dreifuss muscular dystrophy clinically defined by early joint contractures, progressive muscle weakness, and cardiomyopathy. Hopefully, identification of the protein defect may promote new therapeutic strategies concerning muscle fiber development and stability.
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Affiliation(s)
- D S Tews
- Division of Neuropathology, Johannes Gutenberg-University Hospital, Mainz, Germany.
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Ognibene A, Sabatelli P, Petrini S, Squarzoni S, Riccio M, Santi S, Villanova M, Palmeri S, Merlini L, Maraldi NM. Nuclear changes in a case of X-linked Emery-Dreifuss muscular dystrophy. Muscle Nerve 1999; 22:864-9. [PMID: 10398203 DOI: 10.1002/(sici)1097-4598(199907)22:7<864::aid-mus8>3.0.co;2-g] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ultrastructural alterations in the nuclear architecture were found in skeletal muscle and skin cultured cells from a patient affected by X-linked Emery-Dreifuss muscular dystrophy (EMD) carrying a null mutation. The molecular defect of X-linked EMD is the absence of emerin, a nuclear envelope-associated protein which is considered a component of the nuclear lamina. The nuclear changes were present in skeletal muscle and skin cultured cells with a frequency of about 10% and 18%, respectively. The main structures of the nuclear periphery were involved: lamina and nuclear envelope-associated heterochromatin were affected, whereas the cisterna and the pore complexes appeared preserved, and the cytoplasm of the same cells appeared normal. Analogous localized defects were detectable by immunolabeling with antilamin A/C and B2 antibodies, as well as by selective propidium iodide chromatin staining. The lesions we describe could be the result of anomalous nuclear lamina organization in the absence of emerin.
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Affiliation(s)
- A Ognibene
- Laboratorio di Biologia Cellulare e Microscopia Elettronica, Istituti Ortopedici Rizzoli, Bologna, Italy
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Wehnert M, Muntoni F. 60th ENMC International Workshop: non X-linked Emery-Dreifuss Muscular Dystrophy 5-7 June 1998, Naarden, The Netherlands. Neuromuscul Disord 1999; 9:115-21. [PMID: 10220867 DOI: 10.1016/s0960-8966(98)00095-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Funakoshi M, Tsuchiya Y, Arahata K. Emerin and cardiomyopathy in Emery-Dreifuss muscular dystrophy. Neuromuscul Disord 1999; 9:108-14. [PMID: 10220866 DOI: 10.1016/s0960-8966(98)00097-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Emery-Dreifuss muscular dystrophy (EDMD) is an inherited disorder characterized by the clinical triad of life-threatening progressive cardiomyopathy with conduction defect, early onset joint contractures and slow progressive muscle weakness in scapulo-humero-peroneal distribution. Cardiomyopathy in EDMD is usually noticed after the second to third decade of life, and becomes worse with age. Permanent auricular paralysis occurs frequently and is considered a hallmark of EDMD cardiomyopathy. Cardiac involvement may also occur in female carriers. In autopsy cases, enlargement of the atria with remarkable thinning have been observed. Identification of the gene responsible for X-linked EDMD (X-EDMD) and the protein product, emerin, provided a diagnostic clue for EDMD. Since the emerin gene is rather small, the entire sequence can easily be surveyed. Western blot and immunohistochemistry show an absence of emerin in muscle and skin tissues and oral exfoliating cells in male patients with X-EDMD, and a reduction of the protein content with a mosaic expression pattern in female carriers. Emerin anchors at the inner nuclear membrane of cardiac, skeletal and smooth muscles, and interacts with lamins and nucleoplasm, thereby possibly maintaining the mechanical stability of the nuclear membrane of muscle cells that shows rigorous contraction/relaxation. More recently, positive emerin staining at the cardiac demosomes and fasciae adherentes was noticed in addition to the specific localization at the inner nuclear membrane. This localization implies a physiological role for the protein in cardiac conduction.
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Affiliation(s)
- M Funakoshi
- Department of Neuromuscular Research, National Institute of Neuroscience, Tokyo, Japan
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