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Gao Y, Peng L, Zhao C. MYH7 in cardiomyopathy and skeletal muscle myopathy. Mol Cell Biochem 2024; 479:393-417. [PMID: 37079208 DOI: 10.1007/s11010-023-04735-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/07/2023] [Indexed: 04/21/2023]
Abstract
Myosin heavy chain gene 7 (MYH7), a sarcomeric gene encoding the myosin heavy chain (myosin-7), has attracted considerable interest as a result of its fundamental functions in cardiac and skeletal muscle contraction and numerous nucleotide variations of MYH7 are closely related to cardiomyopathy and skeletal muscle myopathy. These disorders display significantly inter- and intra-familial variability, sometimes developing complex phenotypes, including both cardiomyopathy and skeletal myopathy. Here, we review the current understanding on MYH7 with the aim to better clarify how mutations in MYH7 affect the structure and physiologic function of sarcomere, thus resulting in cardiomyopathy and skeletal muscle myopathy. Importantly, the latest advances on diagnosis, research models in vivo and in vitro and therapy for precise clinical application have made great progress and have epoch-making significance. All the great advance is discussed here.
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Affiliation(s)
- Yuan Gao
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Lu Peng
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Cuifen Zhao
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China.
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Abstract
PURPOSE OF REVIEW Tremor is a common neurological symptom with a plethora of potential etiologies. Apart from physiological tremor, the vast majority of tremor syndromes are linked to a pacemaker in the central nervous system (CNS) or, less common, in the peripheral nervous system. Myogenic tremor is a novel tremor entity, first reported in 2019 and believed to originate in the muscle itself. In this review, we describe the clinical properties of myogenic tremor and discuss its presumed pathogenesis on the basis of all of the patient cases published so far. RECENT FINDINGS Myogenic tremor manifests itself as a high frequency, postural, and kinetic tremor with onset in infancy. To date, only myopathies affecting the contractile elements, in particular myosin and a myosin-associated protein, have been recognized to feature myogenic tremor. The generator of the tremor is believed to be located in the sarcomere, with propagation and amplification of sarcomeric oscillatory activity through CNS reflex loops, similar to neuropathic tremor. SUMMARY True myogenic tremor must be distinguished from centrally mediated tremor due to myopathies with central nervous system involvement, i.e., mitochondrial myopathies or myotonic dystrophies. The presence of myogenic tremor strongly points toward a sarcomere-associated mutation and may thus be a valuable clinical tool for the differential diagnosis of myopathies.
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Cotta A, Carvalho E, da-Cunha-Júnior AL, Valicek J, Navarro MM, Junior SB, da Silveira EB, Lima MI, Cordeiro BA, Cauhi AF, Menezes MM, Nunes SV, Vargas AP, Neto RX, Paim JF. Muscle biopsy essential diagnostic advice for pathologists. SURGICAL AND EXPERIMENTAL PATHOLOGY 2021. [DOI: 10.1186/s42047-020-00085-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
Muscle biopsies are important diagnostic procedures in neuromuscular practice. Recent advances in genetic analysis have profoundly modified Myopathology diagnosis.
Main body
The main goals of this review are: (1) to describe muscle biopsy techniques for non specialists; (2) to provide practical information for the team involved in the diagnosis of muscle diseases; (3) to report fundamental rules for muscle biopsy site choice and adequacy; (4) to highlight the importance of liquid nitrogen in diagnostic workup. Routine techniques include: (1) histochemical stains and reactions; (2) immunohistochemistry and immunofluorescence; (3) electron microscopy; (4) mitochondrial respiratory chain enzymatic studies; and (5) molecular studies. The diagnosis of muscle disease is a challenge, as it should integrate data from different techniques.
Conclusion
Formalin-fixed paraffin embedded muscle samples alone almost always lead to inconclusive or unspecific results. Liquid nitrogen frozen muscle sections are imperative for neuromuscular diagnosis. Muscle biopsy interpretation is possible in the context of detailed clinical, neurophysiological, and serum muscle enzymes data. Muscle imaging studies are strongly recommended in the diagnostic workup. Muscle biopsy is useful for the differential diagnosis of immune mediated myopathies, muscular dystrophies, congenital myopathies, and mitochondrial myopathies. Muscle biopsy may confirm the pathogenicity of new gene variants, guide cost-effective molecular studies, and provide phenotypic diagnosis in doubtful cases. For some patients with mitochondrial myopathies, a definite molecular diagnosis may be achieved only if performed in DNA extracted from muscle tissue due to organ specific mutation load.
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Alessi CE, Wu Q, Whitaker CH, Felice KJ. Laing Myopathy: Report of 4 New Families With Novel MYH7 Mutations, Double Mutations, and Severe Phenotype. J Clin Neuromuscul Dis 2020; 22:22-34. [PMID: 32833721 DOI: 10.1097/cnd.0000000000000297] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Laing distal myopathy (LDM) is an autosomal dominant disorder caused by mutations in the slow skeletal muscle fiber myosin heavy chain (MYH7) gene on chromosome 14q11.2. The classic LDM phenotype-including early-onset, initial involvement of foot dorsiflexors and great toe extensors, followed by weakness of neck flexors and finger extensors-is well documented. Since the original report by Laing et al in 1995, the spectrum of MYH7-related myopathies has expanded to include congenital myopathies, late-onset myopathies, myosin storage myopathy, and scapuloperoneal myopathies. Most patients with LDM harbor mutations in the midrod domain of the MYH7 gene, but rare cases document disease-associated mutations in the globular head region. In this report, we add to the medical literature by describing the clinicopathological findings in 8 affected family members from 4 new LDM families-including 2 with novel MYH7 mutations (Y162D and A1438P), one with dual mutations (V39M and K1617del), and one family (E1508del) with severe early-onset weakness associated with contractures, respiratory insufficiency, and dilated cardiomyopathy. Our families highlight the ever-expanding clinical spectrum and genetic variation of the skeletal myopathies related to MYH7 gene mutations.
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Affiliation(s)
| | - Qian Wu
- Pathology and Laboratory Medicine, University of Connecticut School of Medicine, Farmington, CT; and
| | - Charles H Whitaker
- Department of Neuromuscular Medicine, Muscular Dystrophy Association Care Center, Hospital for Special Care, New Britain, CT
| | - Kevin J Felice
- Department of Neuromuscular Medicine, Muscular Dystrophy Association Care Center, Hospital for Special Care, New Britain, CT
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Sarcomeric myopathies associated with tremor: new insights and perspectives. J Muscle Res Cell Motil 2019; 41:285-295. [PMID: 31620961 DOI: 10.1007/s10974-019-09559-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 10/05/2019] [Indexed: 12/21/2022]
Abstract
Myopathies are a large and heterogeneous group of disorders associated with mutations in structural and regulatory genes responsible for proper muscle assembly, organization and function. Despite the molecular diversity of inherited myopathies, they have historically been classified by the phenotypic traits observed in affected patients. It is therefore common for myopathies originating from mutations in different genes to be grouped together due to similar physical manifestations, and conversely myopathies resulting from mutations in the same gene to be considered separately due to disparate symptoms. Herein, we focus on an early onset myopathy linked to inherited or de novo mutations in sarcomeric genes that is characterized by muscle weakness, hypotonia and tremor, and further highlight that it may constitute a new form of myopathy, with tremor as its defining feature. Based on recent reports, we also discuss the possible myogenic origin of the tremor that may start at the level of the sarcomere due to structural and/or contractile alterations occurring as a result of the identified mutations. It is our hope that establishment of this form of myopathy accompanied by myogenic tremor as a new disease entity will have important diagnostic and therapeutic implications.
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Stavusis J, Lace B, Schäfer J, Geist J, Inashkina I, Kidere D, Pajusalu S, Wright NT, Saak A, Weinhold M, Haubenberger D, Jackson S, Kontrogianni-Konstantopoulos A, Bönnemann CG. Novel mutations in MYBPC1 are associated with myogenic tremor and mild myopathy. Ann Neurol 2019; 86:129-142. [PMID: 31025394 DOI: 10.1002/ana.25494] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 04/23/2019] [Accepted: 04/25/2019] [Indexed: 01/11/2023]
Abstract
OBJECTIVE To define a distinct, dominantly inherited, mild skeletal myopathy associated with prominent and consistent tremor in two unrelated, three-generation families. METHODS Clinical evaluations as well as exome and panel sequencing analyses were performed in affected and nonaffected members of two families to identify genetic variants segregating with the phenotype. Histological assessment of a muscle biopsy specimen was performed in 1 patient, and quantitative tremor analysis was carried out in 2 patients. Molecular modeling studies and biochemical assays were performed for both mutations. RESULTS Two novel missense mutations in MYBPC1 (p.E248K in family 1 and p.Y247H in family 2) were identified and shown to segregate perfectly with the myopathy/tremor phenotype in the respective families. MYBPC1 encodes slow myosin binding protein-C (sMyBP-C), a modular sarcomeric protein playing structural and regulatory roles through its dynamic interaction with actin and myosin filaments. The Y247H and E248K mutations are located in the NH2 -terminal M-motif of sMyBP-C. Both mutations result in markedly increased binding of the NH2 terminus to myosin, possibly interfering with normal cross-bridge cycling as the first muscle-based step in tremor genesis. The clinical tremor features observed in all mutation carriers, together with the tremor physiology studies performed in family 2, suggest amplification by an additional central loop modulating the clinical tremor phenomenology. INTERPRETATION Here, we link two novel missense mutations in MYBPC1 with a dominant, mild skeletal myopathy invariably associated with a distinctive tremor. The molecular, genetic, and clinical studies are consistent with a unique sarcomeric origin of the tremor, which we classify as "myogenic tremor." ANN NEUROL 2019.
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Affiliation(s)
- Janis Stavusis
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Baiba Lace
- Latvian Biomedical Research and Study Centre, Riga, Latvia.,Centre Hospitalier Universitaire de Québec, Ville de Québec, QC, Canada
| | - Jochen Schäfer
- Department of Neurology-Uniklinikum CG Carus, Dresden, Germany
| | - Janelle Geist
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD
| | - Inna Inashkina
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Dita Kidere
- Latvian Biomedical Research and Study Centre, Riga, Latvia
| | - Sander Pajusalu
- Department of Clinical Genetics, United Laboratories, Tartu University Hospital, Tartu, Estonia.,Department of Clinical Genetics, Institute of Clinical Medicine, Tartu University, Tartu, Estonia
| | - Nathan T Wright
- Department of Chemistry and Biochemistry, James Madison University, Harrisonburg, VA
| | - Annika Saak
- Department of Neurology-Uniklinikum CG Carus, Dresden, Germany
| | - Manja Weinhold
- Department of Neurology-Uniklinikum CG Carus, Dresden, Germany
| | - Dietrich Haubenberger
- Clinical Trials Unit, Office of the Clinical Director, NINDS Intramural Research Program, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD
| | - Sandra Jackson
- Department of Neurology-Uniklinikum CG Carus, Dresden, Germany
| | | | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD
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Lefter S, Hardiman O, Ryan AM. A population-based epidemiologic study of adult neuromuscular disease in the Republic of Ireland. Neurology 2016; 88:304-313. [DOI: 10.1212/wnl.0000000000003504] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Accepted: 10/14/2016] [Indexed: 12/13/2022] Open
Abstract
Objective:To estimate the prevalence rates (PRs) of acquired and inherited neuromuscular diseases (NMD) in the adult Irish population, reflecting the burden of these conditions in a single country.Methods:This population-based study was performed in the Republic of Ireland (RoI), with a PR estimated for December 2013. Multiple case ascertainment sources were utilized. Demographic and clinical information and relevant diagnostic results were registered.Results:A total of 2,641 adults were identified, giving a PR of 62.6/100,000 (95% confidence interval [CI] 59.95–65.24) for all NMD in RoI. Disease-specific PR include chronic inflammatory demyelinating polyradiculoneuropathy 5.87/100,000 (95% CI 5.06–6.68), Charcot-Marie-Tooth 10.52/100,000 (95% CI 9.44–11.61), hereditary neuropathy with liability to pressure palsies 0.84/100,000 (95% CI 0.54–1.15), myotonic dystrophy type I 6.75/100,000 (95% CI 5.88–7.61), Duchenne muscular dystrophy 3.0/100,000 (95% CI 2.33–3.70), Becker muscular dystrophy 2.2/100,000 (95% CI 1.64–2.88), facioscapulohumeral dystrophy 2.59/100,000 (95% CI 2.05–3.13), limb-girdle muscular dystrophy 2.88/100,000 (95% CI 2.31–3.45), periodic paralysis 1.72/100,000 (95% CI 1.28–2.15), myotonia congenita 0.32/100,000 (95% CI 0.18–0.56), paramyotonia congenita 0.15/100,000 (95% CI 0.06–0.34), Kennedy disease 0.83/100,000 (95% CI 0.40–1.27), Lambert-Eaton myasthenic syndrome 0.29/100,000 (95% CI 0.11–0.47), myasthenia gravis 15.12/100,000 (95% CI 13.82–16.42), and sporadic inclusion body myositis 11.7/100,000 (95% CI 9.82–13.58). PR for amyotrophic lateral sclerosis was established from an existing Register as 7.20/100,000 (95% CI 6.34–8.15).Conclusions:The PR of all adult NMD in RoI is relatively high when compared with other chronic neurologic disorders, although some figures may be an underestimate of the true prevalence. The data provide a framework for international comparison and service planning.
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Laing distal myopathy with a novel mutation in exon 34 of the MYH7 gene. Neuromuscul Disord 2016; 26:598-603. [DOI: 10.1016/j.nmd.2016.06.458] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Revised: 06/19/2016] [Accepted: 06/20/2016] [Indexed: 12/12/2022]
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Finsterer J, Stöllberger C. Heart Disease in Disorders of Muscle, Neuromuscular Transmission, and the Nerves. Korean Circ J 2016; 46:117-34. [PMID: 27014341 PMCID: PMC4805555 DOI: 10.4070/kcj.2016.46.2.117] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 10/30/2015] [Accepted: 11/24/2015] [Indexed: 12/31/2022] Open
Abstract
Little is known regarding cardiac involvement (CI) by neuromuscular disorders (NMDs). The purpose of this review is to summarise and discuss the major findings concerning the types, frequency, and severity of cardiac disorders in NMDs as well as their diagnosis, treatment, and overall outcome. CI in NMDs is characterized by pathologic involvement of the myocardium or cardiac conduction system. Less commonly, additional critical anatomic structures, such as the valves, coronary arteries, endocardium, pericardium, and even the aortic root may be involved. Involvement of the myocardium manifests most frequently as hypertrophic or dilated cardiomyopathy and less frequently as restrictive cardiomyopathy, non-compaction, arrhythmogenic right-ventricular dysplasia, or Takotsubo-syndrome. Cardiac conduction defects and supraventricular and ventricular arrhythmias are common cardiac manifestations of NMDs. Arrhythmias may evolve into life-threatening ventricular tachycardias, asystole, or even sudden cardiac death. CI is common and carries great prognostic significance on the outcome of dystrophinopathies, laminopathies, desminopathies, nemaline myopathy, myotonias, metabolic myopathies, Danon disease, and Barth-syndrome. The diagnosis and treatment of CI in NMDs follows established guidelines for the management of cardiac disease, but cardiotoxic medications should be avoided. CI in NMDs is relatively common and requires complete work-up following the establishment of a neurological diagnosis. Appropriate cardiac treatment significantly improves the overall long-term outcome of NMDs.
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Affiliation(s)
| | - Claudia Stöllberger
- 2 Medical Department with Cardiology and Intensive Care Medicine, Krankenanstalt Rudolfstiftung, Vienna, Austria
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