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Ogasawara M, Nishino I. A review of major causative genes in congenital myopathies. J Hum Genet 2023; 68:215-25. [PMID: 35668205 DOI: 10.1038/s10038-022-01045-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Revised: 04/25/2022] [Accepted: 05/11/2022] [Indexed: 02/07/2023]
Abstract
In this review, we focus on congenital myopathies, which are a genetically heterogeneous group of hereditary muscle diseases with slow or minimal progression. They are mainly defined and classified according to pathological features, with the major subtypes being core myopathy (central core disease), nemaline myopathy, myotubular/centronuclear myopathy, and congenital fiber-type disproportion myopathy. Recent advances in molecular genetics, especially next-generation sequencing technology, have rapidly increased the number of known causative genes for congenital myopathies; however, most of the diseases related to the novel causative genes are extremely rare. There remains no cure for congenital myopathies. However, there have been recent promising findings that could inform the development of therapy for several types of congenital myopathies, including myotubular myopathy, which indicates the importance of prompt and correct diagnosis. This review discusses the major causative genes (NEB, ACTA1, ADSSL1, RYR1, SELENON, MTM1, DNM2, and TPM3) for each subtype of congenital myopathies and the relevant latest findings.
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Abstract
The congenital myopathies are inherited muscle disorders characterized clinically by hypotonia and weakness, usually from birth, with a static or slowly progressive clinical course. Historically, the congenital myopathies have been classified according to major morphological features seen on muscle biopsy as nemaline myopathy, central core disease, centronuclear or myotubular myopathy, and congenital fiber type disproportion. However, in the past two decades, the genetic basis of these different forms of congenital myopathy has been further elucidated with the result being improved correlation with histological and genetic characteristics. However, these notions have been challenged for three reasons. First, many of the congenital myopathies can be caused by mutations in more than one gene that suggests an impact of genetic heterogeneity. Second, mutations in the same gene can cause different muscle pathologies. Third, the same genetic mutation may lead to different pathological features in members of the same family or in the same individual at different ages. This chapter provides a clinical overview of the congenital myopathies and a clinically useful guide to its genetic basis recognizing the increasing reliance of exome, subexome, and genome sequencing studies as first-line analysis in many patients.
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Affiliation(s)
- David S Younger
- Department of Clinical Medicine and Neuroscience, CUNY School of Medicine, New York, NY, United States; Department of Medicine, Section of Internal Medicine and Neurology, White Plains Hospital, White Plains, NY, United States.
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Wang X, Kong C, Liu P, Geng W, Tang H, Berezin A. Identification of Potential Biomarkers for Ryanodine Receptor 1 (RYR1) Mutation-Associated Myopathies Using Bioinformatics Approach. Disease Markers 2022; 2022:1-11. [PMID: 35692882 PMCID: PMC9187445 DOI: 10.1155/2022/8787782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/28/2022] [Indexed: 11/30/2022]
Abstract
Background Myopathies related to Ryanodine receptor 1 (RYR1) mutation are the most common nondystrophy muscle disorder in humans. Early detection and diagnosis of RYR1 mutation-associated myopathies may lead to more timely treatment of patients, which contributes to the management and preparation for malignant hyperthermia. However, diagnosis of RYR1 mutation-associated myopathies is delayed and challenging. The absence of diagnostic morphological features in muscle biopsy does not rule out the possibility of pathogenic variations in RYR1. Accordingly, it is helpful to seek biomarkers to diagnose RYR1 mutation-associated myopathies. Methods Skeletal muscle tissue microarray datasets of RYR1 mutation-associated myopathies or healthy persons were built in accordance with the gene expression synthesis (GEO) database. Differentially expressed genes (DEGs) were identified on the basis of R software. Genes specific to tissue/organ were identified through BioGPS. An enrichment analysis of DEGs was conducted in accordance with the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO). We also built protein-protein interaction (PPI) networks to explore the function and enrichment pathway of DEGs and the identification of hub genes. Lastly, the ROC curve was drawn for hub genes achieving specific expressions within skeletal muscle. Moreover, the area under the curve (AUC) was obtained to calculate the predictive value of key genes. The transcription factors of hub genes achieving specific expressions within skeletal muscle were predicted with the use of the iRegulon plugin. Results We identified 170 DEGs among 11 muscle biopsy samples of healthy subjects and 17 muscle biopsy samples of RYR1 mutation-associated myopathy patients in the dataset. Among the above DEGs, 30 genes achieving specific expressions within tissues/organs were found. GO and KEGG enrichment analysis of DEGs mainly focused on muscle contraction, actin-mediated cell contraction, actin filament-based movement, and muscular sliding. 12 hub genes were identified with the use of Cytoscape. Four hub genes were specifically expressed in skeletal muscle tissue, including MYH1 (AUC: 0.856), TNNT3 (AUC: 0.840), MYLPF (AUC: 0.786), and ATP2A1 (AUC: 0.765). The iRegulon predicted results suggested that the transcription factor MYF6 was found with the highest reliability. Conclusions Four skeletal muscle tissue-specific genes were identified, including MYH1, TNNT3, MYLPF, and ATP2A1, as the potential biomarkers for diagnosing and treating RYR1 mutation-associated myopathies, which provided insights into the transcriptome-level development mechanism. The transcription factor MYF6 may be a vital upstream regulator of the above biomarkers.
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Fusto A, Cassandrini D, Fiorillo C, Codemo V, Astrea G, D’Amico A, Maggi L, Magri F, Pane M, Tasca G, Sabbatini D, Bello L, Battini R, Bernasconi P, Fattori F, Bertini ES, Comi G, Messina S, Mongini T, Moroni I, Panicucci C, Berardinelli A, Donati A, Nigro V, Pini A, Giannotta M, Dosi C, Ricci E, Mercuri E, Minervini G, Tosatto S, Santorelli F, Bruno C, Pegoraro E. Expanding the clinical-pathological and genetic spectrum of RYR1-related congenital myopathies with cores and minicores: an Italian population study. Acta Neuropathol Commun 2022; 10:54. [PMID: 35428369 PMCID: PMC9013059 DOI: 10.1186/s40478-022-01357-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 03/25/2022] [Indexed: 11/10/2022] Open
Abstract
Mutations in the RYR1 gene, encoding ryanodine receptor 1 (RyR1), are a well-known cause of Central Core Disease (CCD) and Multi-minicore Disease (MmD). We screened a cohort of 153 patients carrying an histopathological diagnosis of core myopathy (cores and minicores) for RYR1 mutation. At least one RYR1 mutation was identified in 69 of them and these patients were further studied. Clinical and histopathological features were collected. Clinical phenotype was highly heterogeneous ranging from asymptomatic or paucisymptomatic hyperCKemia to severe muscle weakness and skeletal deformity with loss of ambulation. Sixty-eight RYR1 mutations, generally missense, were identified, of which 16 were novel. The combined analysis of the clinical presentation, disease progression and the structural bioinformatic analyses of RYR1 allowed to associate some phenotypes to mutations in specific domains. In addition, this study highlighted the structural bioinformatics potential in the prediction of the pathogenicity of RYR1 mutations. Further improvement in the comprehension of genotype-phenotype relationship of core myopathies can be expected in the next future: the actual lack of the human RyR1 crystal structure paired with the presence of large intrinsically disordered regions in RyR1, and the frequent presence of more than one RYR1 mutation in core myopathy patients, require designing novel investigation strategies to completely address RyR1 mutation effect.
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Ogasawara M, Nishino I. A review of core myopathy: central core disease, multiminicore disease, dusty core disease, and core-rod myopathy. Neuromuscul Disord 2021; 31:968-977. [PMID: 34627702 DOI: 10.1016/j.nmd.2021.08.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/13/2021] [Accepted: 08/16/2021] [Indexed: 12/21/2022]
Abstract
Core myopathies are clinically, pathologically, and genetically heterogeneous muscle diseases. Their onset and clinical severity are variable. Core myopathies are diagnosed by muscle biopsy showing focally reduced oxidative enzyme activity and can be pathologically divided into central core disease, multiminicore disease, dusty core disease, and core-rod myopathy. Although RYR1-related myopathy is the most common core myopathy, an increasing number of other causative genes have been reported, including SELENON, MYH2, MYH7, TTN, CCDC78, UNC45B, ACTN2, MEGF10, CFL2, KBTBD13, and TRIP4. Furthermore, the genes originally reported to cause nemaline myopathy, namely ACTA1, NEB, and TNNT1, have been recently associated with core-rod myopathy. Genetic analysis allows us to diagnose each core myopathy more accurately. In this review, we aim to provide up-to-date information about core myopathies.
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Affiliation(s)
- Masashi Ogasawara
- Department of Neuromuscular Research, National Center of Neurology and Psychiatry (NCNP), National Institute of Neuroscience, 4-1-1 Ogawahigashi, Tokyo 187-8502, Japan; Medical Genome Center, NCNP, Tokyo, Kodaira, Japan; Department of Pediatrics, Showa General Hospital, Tokyo, Kodaira, Japan
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Center of Neurology and Psychiatry (NCNP), National Institute of Neuroscience, 4-1-1 Ogawahigashi, Tokyo 187-8502, Japan; Medical Genome Center, NCNP, Tokyo, Kodaira, Japan.
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Ogasawara M, Ogawa M, Nonaka I, Hayashi S, Noguchi S, Nishino I. Evaluation of the Core Formation Process in Congenital Neuromuscular Disease With Uniform Type 1 Fiber and Central Core Disease. J Neuropathol Exp Neurol 2021; 79:1370-1375. [PMID: 33184643 DOI: 10.1093/jnen/nlaa104] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Typical central core disease (CCD) is characterized pathologically by the presence of a core and is accompanied by type 1 fiber uniformity. Congenital neuromuscular disease with uniform type 1 fiber (CNMDU1) is characterized pathologically by the presence of type 1 fiber uniformity but without the abnormal structural changes in muscle fibers. Interestingly, typical CCD and 40% of CNMDU1 cases are caused by the same mutations in RYR1, and thus CNMDU1 has been considered an early precursor to CCD. To better understand the nature of CNMDU1, we re-evaluated muscle biopsies from 16 patients with CNMDU1 using immunohistochemistry to RYR1, triadin and TOM20, and compared this to muscle biopsies from 36 typical CCD patients. In CCD, RYR1, and triadin were present in the core regions, while TOM20 was absent in the core regions. Interestingly, in 5 CNMDU1 cases with the RYR1 mutation, RYR1, and triadin were similarly present in core-like areas, while TOM20 was absent in the subsarcolemmal region. Furthermore, there was a correlation between the core position and the disease duration or progression-the older patients in more advanced stages had more centralized cores. Our results indicate that CNMDU1 due to RYR1 mutation is a de facto core myopathy.
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Affiliation(s)
- Masashi Ogasawara
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan.,Department of Genome Medicine Development, Medical Genome Center, NCNP, Kodaira, Japan.,Institute of Medical Genetics, Tokyo Women's Medical University, Tokyo, Japan
| | - Megumu Ogawa
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan
| | - Ikuya Nonaka
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan.,Department of Genome Medicine Development, Medical Genome Center, NCNP, Kodaira, Japan
| | - Shinichiro Hayashi
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan.,Department of Genome Medicine Development, Medical Genome Center, NCNP, Kodaira, Japan
| | - Satoru Noguchi
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan.,Department of Genome Medicine Development, Medical Genome Center, NCNP, Kodaira, Japan
| | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan.,Department of Genome Medicine Development, Medical Genome Center, NCNP, Kodaira, Japan
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Topaloglu H. Core myopathies - a short review. Acta Myol 2020; 39:266-273. [PMID: 33458581 PMCID: PMC7783431 DOI: 10.36185/2532-1900-029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 11/18/2020] [Indexed: 12/01/2022]
Abstract
Congenital myopathies represent a clinically and genetically heterogeneous group of early-onset neuromuscular diseases with characteristic, but not always specific, histopathological features, often presenting with stable and/or slowly progressive truncal and proximal weakness. It is often not possible to have a diagnosis on clinical ground alone. Additional extraocular, respiratory, distal involvement, scoliosis, and distal laxity may provide clues. The "core myopathies" collectively represent the most common form of congenital myopathies, and the name pathologically corresponds to histochemical appearance of focally reduced oxidative enzyme activity and myofibrillar changes on ultrastructural studies. Because of the clinical, pathological, and molecular overlaps, central core disease and multiminicore disease will be discussed together.
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Affiliation(s)
- Haluk Topaloglu
- Correspondence Haluk Topaloglu Yeditepe University Department of Pediatrics, İstanbul, Turkey. E-mail:
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Nix JS, Moore SA. What Every Neuropathologist Needs to Know: The Muscle Biopsy. J Neuropathol Exp Neurol 2020; 79:719-733. [PMID: 32529201 PMCID: PMC7304986 DOI: 10.1093/jnen/nlaa046] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 04/18/2020] [Accepted: 04/28/2020] [Indexed: 12/17/2022] Open
Abstract
Competence in muscle biopsy evaluation is a core component of neuropathology practice. The practicing neuropathologist should be able to prepare frozen sections of muscle biopsies with minimal artifacts and identify key histopathologic features of neuromuscular disease in hematoxylin and eosin-stained sections as well as implement and interpret a basic panel of additional histochemical, enzyme histochemical, and immunohistochemical stains. Important to everyday practice is a working knowledge of normal muscle histology at different ages, muscle motor units, pitfalls of myotendinous junctions, nonpathologic variations encountered at traditional and nontraditional muscle sites, the pathophysiology of myonecrosis and regeneration, and approaches to distinguish muscular dystrophies from inflammatory myopathies and other necrotizing myopathies. Here, we provide a brief overview of what every neuropathologist needs to know concerning the muscle biopsy.
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Affiliation(s)
- James S Nix
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Steven A Moore
- Department of Pathology, Carver College of Medicine, The University of Iowa, Iowa City, Iowa
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Lawal TA, Todd JJ, Witherspoon JW, Bönnemann CG, Dowling JJ, Hamilton SL, Meilleur KG, Dirksen RT. Ryanodine receptor 1-related disorders: an historical perspective and proposal for a unified nomenclature. Skelet Muscle 2020; 10:32. [PMID: 33190635 PMCID: PMC7667763 DOI: 10.1186/s13395-020-00243-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/18/2020] [Indexed: 12/14/2022] Open
Abstract
The RYR1 gene, which encodes the sarcoplasmic reticulum calcium release channel or type 1 ryanodine receptor (RyR1) of skeletal muscle, was sequenced in 1988 and RYR1 variations that impair calcium homeostasis and increase susceptibility to malignant hyperthermia were first identified in 1991. Since then, RYR1-related myopathies (RYR1-RM) have been described as rare, histopathologically and clinically heterogeneous, and slowly progressive neuromuscular disorders. RYR1 variants can lead to dysfunctional RyR1-mediated calcium release, malignant hyperthermia susceptibility, elevated oxidative stress, deleterious post-translational modifications, and decreased RyR1 expression. RYR1-RM-affected individuals can present with delayed motor milestones, contractures, scoliosis, ophthalmoplegia, and respiratory insufficiency. Historically, RYR1-RM-affected individuals were diagnosed based on morphologic features observed in muscle biopsies including central cores, cores and rods, central nuclei, fiber type disproportion, and multi-minicores. However, these histopathologic features are not always specific to RYR1-RM and often change over time. As additional phenotypes were associated with RYR1 variations (including King-Denborough syndrome, exercise-induced rhabdomyolysis, lethal multiple pterygium syndrome, adult-onset distal myopathy, atypical periodic paralysis with or without myalgia, mild calf-predominant myopathy, and dusty core disease) the overlap among diagnostic categories is ever increasing. With the continuing emergence of new clinical subtypes along the RYR1 disease spectrum and reports of adult-onset phenotypes, nuanced nomenclatures have been reported (RYR1- [related, related congenital, congenital] myopathies). In this narrative review, we provide historical highlights of RYR1 research, accounts of the main diagnostic disease subtypes and propose RYR1-related disorders (RYR1-RD) as a unified nomenclature to describe this complex and evolving disease spectrum.
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Affiliation(s)
- Tokunbor A Lawal
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA.
| | - Joshua J Todd
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Jessica W Witherspoon
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Carsten G Bönnemann
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - James J Dowling
- Departments of Paediatrics and Molecular Genetics, Hospital for Sick Children and University of Toronto, Toronto, Canada
| | - Susan L Hamilton
- Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Katherine G Meilleur
- Tissue Injury Branch, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
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Lehmann Urban D, Motlagh Scholle L, Alt K, Ludolph AC, Rosenbohm A. Camptocormia as a Novel Phenotype in a Heterozygous POLG2 Mutation. Diagnostics (Basel) 2020; 10:E68. [PMID: 31991853 DOI: 10.3390/diagnostics10020068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/19/2020] [Accepted: 01/23/2020] [Indexed: 12/04/2022] Open
Abstract
Mitochondrial dysfunction is known to play a key role in the pathophysiological pathway of neurodegenerative disorders. Nuclear-encoded proteins are involved in mtDNA replication, including DNA polymerase gamma, which is the only known replicative mtDNA polymerase, encoded by nuclear genes Polymerase gamma 1 (POLG) and Polymerase gamma 2 (POLG2). POLG mutations are well-known as a frequent cause of mitochondrial myopathies of nuclear origin. However, only rare descriptions of POLG2 mutations leading to mitochondriopathies exist. Here we describe a 68-year-old woman presenting with a 20-year history of camptocormia, mild proximal weakness, and moderate CK increase. Muscle histology showed COX-negative fibres. Genetic analysis by next generation sequencing revealed an already reported heterozygous c.1192-8_1207dup24 mutation in the POLG2 gene. This is the first report on a POLG2 mutation leading to camptocormia as the main clinical phenotype, extending the phenotypic spectrum of POLG2 associated diseases. This underlines the broad phenotypic spectrum found in mitochondrial diseases, especially in mitochondrial disorders of nuclear origin.
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Avnon T, Svirsky R, Orr-Urtreger A, Sagie L, Fattal-Valevski A, Fellig Y, Ben-Shachar S. Clinical Observation: Effect of a Second Transpositioned Variant in a Family with Autosomal Dominant Ryanodine Receptor-1-Related Disease. J Pediatr Genet 2019; 9:121-124. [PMID: 32341817 DOI: 10.1055/s-0039-1698445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/05/2019] [Indexed: 10/25/2022]
Abstract
Mutations in the ryanodine receptor-1 ( RYR1 ) may cause disorders inherited in an autosomal dominant/recessive fashion. Sequencing of RYR1 in an infant of Ashkenazi Jewish descent with severe hypotonia, dislocation of hip, torticollis and scoliosis, and paternal family history of autosomal dominant mild disease. The child was compound heterozygote for a missense variant c.7042G > A inherited from her father associated with autosomal dominant disease, and a missense variant of unknown significance c.5309C > T inherited from an asymptomatic mother. This case raises the possibility of a dominant disease complicated by a second variant in the other allele serving as a modifier.
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Affiliation(s)
- Tomer Avnon
- Department of Obstetrics and Gynecology, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ran Svirsky
- Genetics Institute, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Avi Orr-Urtreger
- Genetics Institute, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Liora Sagie
- Pediatric Neurology Institute, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Aviva Fattal-Valevski
- Pediatric Neurology Institute, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yakov Fellig
- Department of Pathology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Shay Ben-Shachar
- Genetics Institute, Tel Aviv Sourasky Medical Center, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Sadhasivam S, Brandom BW, Henker RA, McAuliffe JJ. Bayesian modeling to predict malignant hyperthermia susceptibility and pathogenicity of RYR1, CACNA1S and STAC3 variants. Pharmacogenomics 2019; 20:989-1003. [PMID: 31559918 PMCID: PMC7006767 DOI: 10.2217/pgs-2019-0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/17/2019] [Indexed: 11/21/2022] Open
Abstract
Aim: Identify variants in RYR1, CACNA1S and STAC3, and predict malignant hyperthermia (MH) pathogenicity using Bayesian statistics in individuals clinically treated as MH susceptible (MHS). Materials & methods: Whole exome sequencing including RYR1, CACNA1S and STAC3 performed on 64 subjects with: MHS; suspected MH event or first-degree relative; and MH negative. Variant pathogenicity was estimated using in silico analysis, allele frequency and prior data to calculate Bayesian posterior probabilities. Results: Bayesian statistics predicted CACNA1S variant p.Thr1009Lys and RYR1 variants p.Ser1728Phe and p.Leu4824Pro are likely pathogenic, and novel STAC3 variant p.Met187Thr has uncertain significance. Nearly a third of MHS subjects had only benign variants. Conclusion: Bayesian method provides new approach to predict MH pathogenicity of genetic variants.
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Affiliation(s)
- Senthilkumar Sadhasivam
- Department of Anesthesia, Riley Hospital for Children at Indiana University Health, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Barbara W Brandom
- The North American Malignant Hyperthermia Registry of the Malignant Hyperthermia Association of the United States (MHAUS), Department of Nurse Anesthesia, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Richard A Henker
- The North American Malignant Hyperthermia Registry of the Malignant Hyperthermia Association of the United States (MHAUS), Department of Nurse Anesthesia, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - John J McAuliffe
- Department of Anesthesia, Cincinnati Children's Hospital Medical Center, The University of Cincinnati, Cincinnati, OH 45229, USA
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Abstract
Congenital myopathies (CM) are a genetically heterogeneous group of neuromuscular disorders most commonly presenting with neonatal/childhood-onset hypotonia and muscle weakness, a relatively static or slowly progressive disease course, and originally classified into subcategories based on characteristic histopathologic findings in muscle biopsies. This enduring concept of disease definition and classification based on the clinicopathologic phenotype was pioneered in the premolecular era. Advances in molecular genetics have brought into focus the increased blurring of the original seemingly "watertight" categories through broadening of the clinical phenotypes in existing genes, and continuous identification of novel genetic backgrounds. This review summarizes the histopathologic landscape of the 4 "classical" subtypes of CM-nemaline myopathies, core myopathies, centronuclear myopathies, and congenital fiber type disproportion and some of the emerging and novel genetic diseases with a CM presentation.
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Affiliation(s)
- Rahul Phadke
- Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children and Division of Neuropathology, National Hospital for Neurology and Neurosurgery, London, UK; Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK.
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Knuiman GJ, Küsters B, Eshuis L, Snoeck M, Lammens M, Heytens L, De Ridder W, Baets J, Scalco RS, Quinlivan R, Holton J, Bodi I, Wraige E, Radunovic A, von Landenberg C, Reimann J, Kamsteeg EJ, Sewry C, Jungbluth H, Voermans NC. The histopathological spectrum of malignant hyperthermia and rhabdomyolysis due to RYR1 mutations. J Neurol 2019; 266:876-887. [PMID: 30788618 PMCID: PMC6420893 DOI: 10.1007/s00415-019-09209-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 01/16/2019] [Accepted: 01/19/2019] [Indexed: 12/22/2022]
Abstract
Objective The histopathological features of malignant hyperthermia (MH) and non-anaesthetic (mostly exertional) rhabdomyolysis (RM) due to RYR1 mutations have only been reported in a few cases. Methods We performed a retrospective multi-centre cohort study focussing on the histopathological features of patients with MH or RM due to RYR1 mutations (1987–2017). All muscle biopsies were reviewed by a neuromuscular pathologist. Additional morphometric and electron microscopic analysis were performed where possible. Results Through the six participating centres we identified 50 patients from 46 families, including patients with MH (n = 31) and RM (n = 19). Overall, the biopsy of 90% of patients showed one or more myopathic features including: increased fibre size variability (n = 44), increase in the number of fibres with internal nuclei (n = 30), and type I fibre predominance (n = 13). Abnormalities on oxidative staining, generally considered to be more specifically associated with RYR1-related congenital myopathies, were observed in 52%, and included unevenness (n = 24), central cores (n = 7) and multi-minicores (n = 3). Apart from oxidative staining abnormalities more frequently observed in MH patients, the histopathological spectrum was similar between the two groups. There was no correlation between the presence of cores and the occurrence of clinically detectable weakness or presence of (likely) pathogenic variants. Conclusions Patients with RYR1-related MH and RM exhibit a similar histopathological spectrum, ranging from mild myopathic changes to cores and other features typical of RYR1-related congenital myopathies. Suggestive histopathological features may support RYR1 involvement, also in cases where the in vitro contracture test is not informative. Electronic supplementary material The online version of this article (10.1007/s00415-019-09209-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- G J Knuiman
- Department of Pathology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - B Küsters
- Department of Pathology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - L Eshuis
- Department of Pathology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - M Snoeck
- National MH Investigation Unit, Department of Anaesthesiology, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands
| | - M Lammens
- Department of Pathology, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - L Heytens
- Malignant Hyperthermia Research Unit, University of Antwerp, Antwerp, Belgium
| | - W De Ridder
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
- Department of Neurology, Neuromuscular Reference Centre, Antwerp University Hospital, Antwerp, Belgium
| | - J Baets
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium
- Laboratory of Neuromuscular Pathology, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium
- Department of Neurology, Neuromuscular Reference Centre, Antwerp University Hospital, Antwerp, Belgium
| | - R S Scalco
- MRC Centre for Neuromuscular Diseases, Institute of Neurology, University College London, London, UK
| | - R Quinlivan
- MRC Centre for Neuromuscular Diseases, Institute of Neurology, University College London, London, UK
| | - J Holton
- MRC Centre for Neuromuscular Diseases, Institute of Neurology, University College London, London, UK
| | - I Bodi
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| | - E Wraige
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
| | - A Radunovic
- Barts Neuromuscular Diseases Centre, Royal London Hospital, London, UK
| | - C von Landenberg
- Muscle Lab, Department of Neurology, University of Bonn Medical Centre, Bonn, Germany
| | - J Reimann
- Muscle Lab, Department of Neurology, University of Bonn Medical Centre, Bonn, Germany
| | - E-J Kamsteeg
- Department of Human Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - C Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital for Children, London, UK
| | - H Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina Children's Hospital, Guy's and St Thomas' Hospital NHS Foundation Trust, London, UK
- Muscle Signalling Section, Randall Division for Cell and Molecular Biophysics, King's College, London, UK
- Department of Basic and Clinical Neuroscience, King's College, IoPPN, London, UK
| | - N C Voermans
- Department of Neurology, Radboud University Medical Centre, Nijmegen, The Netherlands.
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16
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Schubert J, Tariq M, Geddes G, Kindel S, Miller EM, Ware SM. Novel pathogenic variants in filamin C identified in pediatric restrictive cardiomyopathy. Hum Mutat 2018; 39:2083-2096. [DOI: 10.1002/humu.23661] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Revised: 08/29/2018] [Accepted: 09/25/2018] [Indexed: 12/31/2022]
Affiliation(s)
- Jeffrey Schubert
- Department of Molecular Genetics, Microbiology, and Biochemistry; University of Cincinnati College of Medicine; Cincinnati Ohio
- Departments of Pediatrics and Medical and Molecular Genetics; Indiana University School of Medicine; Indianapolis Indiana
| | - Muhammad Tariq
- Faculty of Applied Medical Science; University of Tabuk; Tabuk Kingdom of Saudi Arabia
| | - Gabrielle Geddes
- Department of Pediatrics; Medical College of Wisconsin; Milwaukee Wisconsin
| | - Steven Kindel
- Department of Pediatrics; Medical College of Wisconsin; Milwaukee Wisconsin
| | - Erin M. Miller
- Cincinnati Children's Hospital Medical Center; Cincinnati Ohio
| | - Stephanie M. Ware
- Departments of Pediatrics and Medical and Molecular Genetics; Indiana University School of Medicine; Indianapolis Indiana
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17
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Abstract
Ryanodine receptor type 1-related myopathies (RYR1-RM) are the most common class of congenital myopathies. Historically, RYR1-RM classification and diagnosis have been guided by histopathologic findings on muscle biopsy. Main histological subtypes of RYR1-RM include central core disease, multiminicore disease, core-rod myopathy, centronuclear myopathy, and congenital fiber-type disproportion. A range of RYR1-RM clinical phenotypes has also emerged more recently and includes King Denborough syndrome, RYR1 rhabdomyolysis-myalgia syndrome, atypical periodic paralysis, congenital neuromuscular disease with uniform type 1 fibers, and late-onset axial myopathy. This expansion of the RYR1-RM disease spectrum is due, in part, to implementation of next-generation sequencing methods, which include the entire RYR1 coding sequence rather than being restricted to hotspot regions. These methods enhance diagnostic capabilities, especially given historic limitations of histopathologic and clinical overlap across RYR1-RM. Both dominant and recessive modes of inheritance have been documented, with the latter typically associated with a more severe clinical phenotype. As with all congenital myopathies, no FDA-approved treatments exist to date. Here, we review histopathologic, clinical, imaging, and genetic diagnostic features of the main RYR1-RM subtypes. We also discuss the current state of treatments and focus on disease-modulating (nongenetic) therapeutic strategies under development for RYR1-RM. Finally, perspectives for future approaches to treatment development are broached.
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Affiliation(s)
- Tokunbor A Lawal
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Joshua J Todd
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA
| | - Katherine G Meilleur
- Neuromuscular Symptoms Unit, National Institute of Nursing Research, National Institutes of Health, Bethesda, MD, USA.
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18
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Abstract
Congenital myopathies are clinically and genetically a heterogeneous group of early onset neuromuscular disorders, characterized by hypotonia and muscle weakness. Clinical severity and age of onset are variable. Many patients are severely affected at birth while others have a milder, moderately progressive or nonprogressive phenotype. Respiratory weakness is a major clinical aspect that requires regular monitoring. Causative mutations in several genes have been identified that are inherited in a dominant, recessive or X-linked manner, or arise de novo. Muscle biopsies show characteristic pathological features such as nemaline rods/bodies, cores, central nuclei or caps. Small type 1 fibres expressing slow myosin are a common feature and may sometimes be the only abnormality. Small cores (minicores) devoid of mitochondria and areas showing variable myofibrillar disruption occur in several neuromuscular disorders including several forms of congenital myopathy. Muscle biopsies can also show more than one structural defect. There is considerable clinical, pathological and genetic overlap with mutations in one gene resulting in more than one pathological feature, and the same pathological feature being associated with defects in more than one gene. Increasing application of whole exome sequencing is broadening the clinical and pathological spectra in congenital myopathies, but pathology still has a role in clarifying the pathogenicity of gene variants as well as directing molecular analysis.
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Affiliation(s)
- C A Sewry
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health and Great Ormond Street Hospital for Children, London, UK.,Wolfson Centre for Inherited Neuromuscular Diseases, RJAH Orthopaedic Hospital, Oswestry, UK
| | - C Wallgren-Pettersson
- The Folkhälsan Institute of Genetics and the Department of Medical and Clinical Genetics, University of Helsinki, Helsinki, Finland
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19
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Kondo T, Yasuda T, Mukaida K, Otsuki S, Kanzaki R, Miyoshi H, Hamada H, Nishino I, Kawamoto M. Genetic and functional analysis of the RYR1 mutation p.Thr84Met revealed a susceptibility to malignant hyperthermia. J Anesth 2018; 32:174-181. [DOI: 10.1007/s00540-018-2451-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/06/2018] [Indexed: 01/31/2023]
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20
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Abstract
Ryanodine receptors (RyRs) are ubiquitous intracellular calcium (Ca2+) release channels required for the function of many organs including heart and skeletal muscle, synaptic transmission in the brain, pancreatic beta cell function, and vascular tone. In disease, defective function of RyRs due either to stress (hyperadrenergic and/or oxidative overload) or genetic mutations can render the channels leaky to Ca2+ and promote defective disease-causing signals as observed in heat failure, muscular dystrophy, diabetes mellitus, and neurodegerative disease. RyRs are massive structures comprising the largest known ion channel-bearing macromolecular complex and exceeding 3 million Daltons in molecular weight. RyRs mediate the rapid release of Ca2+ from the endoplasmic/sarcoplasmic reticulum (ER/SR) to stimulate cellular functions through Ca2+-dependent processes. Recent advances in single-particle cryogenic electron microscopy (cryo-EM) have enabled the determination of atomic-level structures for RyR for the first time. These structures have illuminated the mechanisms by which these critical ion channels function and interact with regulatory ligands. In the present chapter we discuss the structure, functional elements, gating and activation mechanisms of RyRs in normal and disease states.
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Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular Cardiology, Department of Physiology and Cellular Biophysics, Columbia University Medical Center, New York, NY, USA
- The Wilf Family Cardiovascular Research Institute and the Einstein-Mount Sinai Diabetes Research Center, Department of Medicine, Albert Einstein College of Medicine - Montefiore University Hospital, New York, NY, USA
| | - Daniel Lewis
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Amedee des Georges
- Advanced Science Research Center at the Graduate Center of the City University of New York, New York, NY, USA
- Department of Chemistry & Biochemistry, City College of New York, New York, NY, USA
- Ph.D. Program in Biochemistry, The Graduate Center of the City University of New York, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
- Department of Medicine, Columbia University, New York, NY, USA
| | - Joachim Frank
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.
- Department of Biological Sciences, Columbia University, New York, NY, USA.
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21
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Cassandrini D, Trovato R, Rubegni A, Lenzi S, Fiorillo C, Baldacci J, Minetti C, Astrea G, Bruno C, Santorelli FM. Congenital myopathies: clinical phenotypes and new diagnostic tools. Ital J Pediatr 2017; 43:101. [PMID: 29141652 PMCID: PMC5688763 DOI: 10.1186/s13052-017-0419-z] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Accepted: 11/02/2017] [Indexed: 12/26/2022] Open
Abstract
Congenital myopathies are a group of genetic muscle disorders characterized clinically by hypotonia and weakness, usually from birth, and a static or slowly progressive clinical course. Historically, congenital myopathies have been classified on the basis of major morphological features seen on muscle biopsy. However, different genes have now been identified as associated with the various phenotypic and histological expressions of these disorders, and in recent years, because of their unexpectedly wide genetic and clinical heterogeneity, next-generation sequencing has increasingly been used for their diagnosis. We reviewed clinical and genetic forms of congenital myopathy and defined possible strategies to improve cost-effectiveness in histological and imaging diagnosis.
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Affiliation(s)
| | - Rosanna Trovato
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Anna Rubegni
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Sara Lenzi
- Neurology, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Chiara Fiorillo
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
| | - Jacopo Baldacci
- Molecular Medicine, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Carlo Minetti
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G. Gaslini, Genoa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genova, Genoa, Italy
| | - Guja Astrea
- Neurology, IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Claudio Bruno
- Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto G. Gaslini, Genoa, Italy
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22
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Santulli G, Lewis DR, Marks AR. Physiology and pathophysiology of excitation-contraction coupling: the functional role of ryanodine receptor. J Muscle Res Cell Motil 2017; 38:37-45. [PMID: 28653141 PMCID: PMC5813681 DOI: 10.1007/s10974-017-9470-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 04/06/2017] [Indexed: 12/21/2022]
Abstract
Calcium (Ca2+) release from intracellular stores plays a key role in the regulation of skeletal muscle contraction. The type 1 ryanodine receptors (RyR1) is the major Ca2+ release channel on the sarcoplasmic reticulum (SR) of myocytes in skeletal muscle and is required for excitation-contraction (E-C) coupling. This article explores the role of RyR1 in skeletal muscle physiology and pathophysiology.
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Affiliation(s)
- Gaetano Santulli
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Daniel R Lewis
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA
| | - Andrew R Marks
- The Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA.
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, Columbia University, New York, NY, USA.
- Department of Medicine, Columbia University, New York, NY, USA.
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23
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Alvarellos ML, Krauss RM, Wilke RA, Altman RB, Klein TE. PharmGKB summary: very important pharmacogene information for RYR1. Pharmacogenet Genomics 2016; 26:138-44. [PMID: 26709912 DOI: 10.1097/FPC.0000000000000198] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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24
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Fiorillo C, Astrea G, Savarese M, Cassandrini D, Brisca G, Trucco F, Pedemonte M, Trovato R, Ruggiero L, Vercelli L, D'Amico A, Tasca G, Pane M, Fanin M, Bello L, Broda P, Musumeci O, Rodolico C, Messina S, Vita GL, Sframeli M, Gibertini S, Morandi L, Mora M, Maggi L, Petrucci A, Massa R, Grandis M, Toscano A, Pegoraro E, Mercuri E, Bertini E, Mongini T, Santoro L, Nigro V, Minetti C, Santorelli FM, Bruno C. MYH7-related myopathies: clinical, histopathological and imaging findings in a cohort of Italian patients. Orphanet J Rare Dis 2016; 11:91. [PMID: 27387980 PMCID: PMC4936326 DOI: 10.1186/s13023-016-0476-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/22/2016] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Myosin heavy chain 7 (MYH7)-related myopathies are emerging as an important group of muscle diseases of childhood and adulthood, with variable clinical and histopathological expression depending on the type and location of the mutation. Mutations in the head and neck domains are a well-established cause of hypertrophic cardiomyopathy whereas mutation in the distal regions have been associated with a range of skeletal myopathies with or without cardiac involvement, including Laing distal myopathy and Myosin storage myopathy. Recently the spectrum of clinical phenotypes associated with mutations in MYH7 has increased, blurring this scheme and adding further phenotypes to the list. A broader disease spectrum could lead to misdiagnosis of different congenital myopathies, neurogenic atrophy and other neuromuscular conditions. RESULTS As a result of a multicenter Italian study we collected clinical, histopathological and imaging data from a population of 21 cases from 15 families, carrying reported or novel mutations in MYH7. Patients displayed a variable phenotype including atypical pictures, as dropped head and bent spine, which cannot be classified in previously described groups. Half of the patients showed congenital or early infantile weakness with predominant distal weakness. Conversely, patients with later onset present prevalent proximal weakness. Seven patients were also affected by cardiomyopathy mostly in the form of non-compacted left ventricle. Muscle biopsy was consistent with minicores myopathy in numerous cases. Muscle MRI was meaningful in delineating a shared pattern of selective involvement of tibialis anterior muscles, with relative sparing of quadriceps. CONCLUSION This work adds to the genotype-phenotype correlation of MYH7-relatedmyopathies confirming the complexity of the disorder.
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Affiliation(s)
- C Fiorillo
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy. .,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy.
| | - G Astrea
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - M Savarese
- Telethon Institute of Genetics and Medicine, Naples, Italy
| | - D Cassandrini
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - G Brisca
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy.,Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto Giannina Gaslini, Genoa, Italy
| | - F Trucco
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - M Pedemonte
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - R Trovato
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - L Ruggiero
- Department of Neurosciences and Reproductive and Odontostomatologic Sciences, University Federico II, Naples, Italy
| | - L Vercelli
- Department of Neurosciences "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - A D'Amico
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - G Tasca
- Don Carlo Gnocchi ONLUS Foundation, Rome, Italy
| | - M Pane
- Department of Paediatric Neurology, Catholic University, Rome, Italy
| | - M Fanin
- Department of Neurosciences, University of Padua, Padua, Italy
| | - L Bello
- Department of Neurosciences, University of Padua, Padua, Italy
| | - P Broda
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy
| | - O Musumeci
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - C Rodolico
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - S Messina
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - G L Vita
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - M Sframeli
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - S Gibertini
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - L Morandi
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - M Mora
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - L Maggi
- Neuromuscular Diseases and Neuroimmunology Unit, IRCCS Foundation C Besta Neurological Institute, Milan, Italy
| | - A Petrucci
- Center for Neuromuscular and Neurological Rare Diseases, S. Camillo-Forlanini Hospital, Rome, Italy
| | - R Massa
- Department of Systems Medicine (Neurology), University of Tor Vergata, Rome, Italy
| | - M Grandis
- Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy
| | - A Toscano
- Department of Clinical and Experimental Medicine and Nemo Sud Clinical Centre, University of Messina, Messina, Italy
| | - E Pegoraro
- Department of Neurosciences, University of Padua, Padua, Italy
| | - E Mercuri
- Department of Paediatric Neurology, Catholic University, Rome, Italy
| | - E Bertini
- Unit of Neuromuscular and Neurodegenerative Disorders, Department of Neurosciences, IRCCS Bambino Gesù Children's Hospital, Rome, Italy
| | - T Mongini
- Department of Neurosciences "Rita Levi Montalcini", University of Turin, Turin, Italy
| | - L Santoro
- Department of Neurosciences and Reproductive and Odontostomatologic Sciences, University Federico II, Naples, Italy
| | - V Nigro
- Telethon Institute of Genetics and Medicine, Naples, Italy
| | - C Minetti
- Unit of Pediatric Neurology and Muscular Disorders, Istituto G.Gaslini, Genoa, Italy.,Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternad and Child Health, University of Genova, University of Genoa, Genoa, Italy
| | - F M Santorelli
- IRCCS Stella Maris, Molecular Medicine and Neuromuscular Disorders, Via dei Giacinti 2, 56128, Calambrone, Pisa, Italy
| | - C Bruno
- Department of Neuroscience, Center of Myology and Neurodegenerative Disorders, Istituto Giannina Gaslini, Genoa, Italy
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25
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Abstract
Central core disease is a nonprogressive or slowly progressive congenital myopathy with a variable degree of hypotonia and axial and proximal muscle weakness that is histologically characterized by areas devoid of oxidative enzyme activity, resulting from an absence or low numbers of mitochondria in these regions (central core). A 10-month-old, male, pony foal was examined because of stiff gait, marked contractures of the distal portion of the limbs, flexion deformities of the hooves, and moderate hypotonia that had been present from birth. The foal had increased creatine kinase (282 U/ liter; reference interval 10-135 U/liter), lactate dehydrogenase (1,188 U/liter; reference interval 150–450 U/liter), and aspartate transaminase (377 U/liter; reference interval <290 U/liter) activities, suggesting muscle disease. Muscle biopsy was performed. In cytochrome oxidase-, succinate dehydrogenase-, and reduced nicotinamide adenine dinucleotide tetrazolium reductase-reacted sections, the dominant morphologic feature was the absence of oxidative enzyme activity in the cores. By use of immunohistochemical technique with a monoclonal antibody against desmin, the cores were clearly delineated and a desmin network was present within the cores. Ultrastructurally, the core areas were characterized by preserved sarcomeres with irregular Z-lines, with some streaming or zigzag appearance and abnormal sarcoplasmic reticulum profiles and T-tubules. Lack of mitochrondria within central cores was observed. Diagnosis of myopathy with central cores was made.
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Affiliation(s)
- O Paciello
- Department of Pathology and Animal Health, University of Naples Federico II Via Delpino, 1 80137, Naples (Italy).
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26
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Juo LY, Liao WC, Shih YL, Yang BY, Liu AB, Yan YT. HSPB7 interacts with dimerized FLNC and its absence results in progressive myopathy in skeletal muscles. J Cell Sci 2016; 129:1661-70. [PMID: 26929074 PMCID: PMC4852768 DOI: 10.1242/jcs.179887] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 02/17/2016] [Indexed: 12/30/2022] Open
Abstract
HSPB7 belongs to the small heat-shock protein (sHSP) family, and its expression is restricted to cardiac and skeletal muscles from embryonic stages to adulthood. Here, we found that skeletal-muscle-specific ablation of the HspB7 does not affect myogenesis during embryonic stages to postnatal day 1 (P1), but causes subsequent postnatal death owing to a respiration defect, with progressive myopathy phenotypes in the diaphragm. Deficiency of HSPB7 in the diaphragm muscle resulted in muscle fibrosis, sarcomere disarray and sarcolemma integrity loss. We identified dimerized filamin C (FLNC) as an interacting partner of HSPB7. Immunofluorescence studies demonstrated that the aggregation and mislocalization of FLNC occurred in the muscle of HspB7 mutant adult mice. Furthermore, the components of dystrophin glycoprotein complex, γ- and δ-sarcoglycan, but not dystrophin, were abnormally upregulated and mislocalized in HSPB7 mutant muscle. Collectively, our findings suggest that HSPB7 is essential for maintaining muscle integrity, which is achieved through its interaction with FLNC, in order to prevent the occurrence and progression of myopathy. Highlighted Article: HSPB7 plays a crucial role in the maintenance of the muscle integrity, possibly through stabilizing the function of FLNC.
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Affiliation(s)
- Liang-Yi Juo
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Wern-Chir Liao
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Yen-Ling Shih
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - Bih-Ying Yang
- Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
| | - An-Bang Liu
- Department of Neurology, Buddhist Tzu Chi General Hospital and Buddhist Tzu Chi University, Hualien 970, Taiwan
| | - Yu-Ting Yan
- Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei 112, Taiwan Institute of Biomedical Sciences, Academia Sinica, Taipei 115, Taiwan
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27
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Hernández-Ochoa EO, Pratt SJP, Lovering RM, Schneider MF. Critical Role of Intracellular RyR1 Calcium Release Channels in Skeletal Muscle Function and Disease. Front Physiol 2016; 6:420. [PMID: 26793121 PMCID: PMC4709859 DOI: 10.3389/fphys.2015.00420] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/21/2015] [Indexed: 01/25/2023] Open
Abstract
The skeletal muscle Ca2+ release channel, also known as ryanodine receptor type 1 (RyR1), is the largest ion channel protein known and is crucial for effective skeletal muscle contractile activation. RyR1 function is controlled by Cav1.1, a voltage gated Ca2+ channel that works mainly as a voltage sensor for RyR1 activity during skeletal muscle contraction and is also fine-tuned by Ca2+, several intracellular compounds (e.g., ATP), and modulatory proteins (e.g., calmodulin). Dominant and recessive mutations in RyR1, as well as acquired channel alterations, are the underlying cause of various skeletal muscle diseases. The aim of this mini review is to summarize several current aspects of RyR1 function, structure, regulation, and to describe the most common diseases caused by hereditary or acquired RyR1 malfunction.
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Affiliation(s)
- Erick O Hernández-Ochoa
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
| | - Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Martin F Schneider
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine Baltimore, MD, USA
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Luciano RDP, Puertas EB, Martins DE, Faloppa F, Del Curto D, Rodrigues LMR, Schmidt B, de Oliveira ASB, Wajchenberg M. Adolescent idiopathic scoliosis without limb weakness: a differential diagnosis of core myopathy? BMC Musculoskelet Disord 2015; 16:179. [PMID: 26242231 PMCID: PMC4524392 DOI: 10.1186/s12891-015-0629-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 07/13/2015] [Indexed: 11/10/2022] Open
Abstract
Background Core myopathies are a clinically and genetically heterogeneous group of congenital myopathies with the common defined histopathological feature of focally reduced oxidative activity on muscle biopsy. It has a low incidence, however, recent articles show broad clinical spectrum, suggesting that the real incidence should be considerably larger than previously described. Due to the important association between scoliosis and paravertebral muscle imbalance, numerous authors study, by biopsy of the spinal rotator muscles, potential changes that may elucidate the etiology of adolescent idiopathic scoliosis. Case presentation Two patients have been followed at Spine Group of Department of Orthopedics at Federal University of São Paulo, with an initial diagnosis of idiopathic scoliosis. Both patients had clinical and radiological findings compatible with it. The patients authorized, through the Term of Consent, intraoperative biopsy of muscle multifidus from the apex of the thoracic curve on concave and convex sides. After muscle biopsy was performed a histopathological analysis. As regard to the histopathological features: in both patients were identified, the presence of core structures in extensive areas with reduced oxidative activity running along the muscle fiber. Conclusions All patients with ‘idiopathic’ scoliosis deserve a careful neurological evaluation, even if they have minimal muscle symptoms in the extremities. The frequent occurrence of scoliosis in patients with CORE Myopathies, supports the thesis that the change in the paravertebral muscle fiber must be the underlying pathogenic factor in scoliosis and may help us understand the onset and progression of curves in patients previously diagnosed with idiopathic scoliosis.
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Affiliation(s)
- Rafael de Paiva Luciano
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - Eduardo Barros Puertas
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - Delio Eulalio Martins
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - Flavio Faloppa
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - David Del Curto
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - Luciano Miller Reis Rodrigues
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - Beny Schmidt
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - Acary Souza Bulle de Oliveira
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
| | - Marcelo Wajchenberg
- Universidade Federal de Sao Paulo - Brazil - R. Borges Lagoa, 783, 5 andar, Vila Clementino, SP, Zip Code - 04038-031, Brazil.
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Remiche G, Kadhim H, Abramowicz M, Mavroudakis N, Monnier N, Lunardi J. A novel large deletion in the RYR1 gene in a Belgian family with late-onset and recessive core myopathy. Neuromuscul Disord 2015; 25:397-402. [PMID: 25747005 DOI: 10.1016/j.nmd.2015.01.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 01/20/2015] [Accepted: 01/25/2015] [Indexed: 11/15/2022]
Abstract
We report a novel and particularly unusual type of mutation, namely, large deletion in the RYR1 gene, in a Belgian family with myopathy: Patients were found to be compound heterozygous and presented a clinico-pathological phenotype characterized by late-onset and recessive myopathy with cores. We depict the clinical, electrophysiological, pathological and molecular genetic characteristics of family members. To date, large deletions in the RYR1 gene have been reported in only two cases. Both involved different mutations and, in sharp contrast to our cases, presented with a very early-onset, neonatal, and a very severe or lethal phenotype. Overview of reported clinico-pathologic phenotypes, also highlights the rarity of combined late-onset/recessive co-occurrence in this group of myopathies with cores. Finally, this report underlines the broadening spectrum in this group of myopathologic disorders and highlights the concept of 'RYR1-associated/related core myopathies'.
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Affiliation(s)
- Gauthier Remiche
- Centre de Référence Neuromusculaire, Service de Neurologie, Hôpital Erasme, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium
| | - Hazim Kadhim
- Unité de Neuropathologie, CHU Brugmann, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium.
| | - Marc Abramowicz
- Service de Génétique médicale, Hôpital Erasme, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium
| | - Nicolas Mavroudakis
- Centre de Référence Neuromusculaire, Service de Neurologie, Hôpital Erasme, Université Libre de Bruxelles (U.L.B.), Brussels, Belgium
| | - Nicole Monnier
- Biochimie et Génétique moléculaire, Institut de Biologie et Pathologie, CHU Grenoble, France
| | - Joël Lunardi
- Biochimie et Génétique moléculaire, Institut de Biologie et Pathologie, CHU Grenoble, France
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Jung NY, Park YE, Shin JH, Lee CH, Jung DS, Kim DS. Mild Clinical Features and Histopathologically Atypical Cores in Two Korean Families with Central Core Disease Harboring RYR1 Mutations at the C-Terminal Region. J Clin Neurol 2014; 11:97-101. [PMID: 25628744 PMCID: PMC4302187 DOI: 10.3988/jcn.2015.11.1.97] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 10/21/2013] [Accepted: 10/22/2013] [Indexed: 12/26/2022] Open
Abstract
Background Central core disease (CCD) is a congenital myopathy characterized by distinctive cores in muscle fibers. Mutations in the gene encoding ryanodine receptor 1 (RYR1) have been identified in most CCD patients. Case Report Two unrelated patients presented with slowly progressive or nonprogressive proximal muscle weakness since childhood. Their family history revealed some members with the same clinical problem. Histological analysis of muscle biopsy samples revealed numerous peripheral cores in the muscle fibers. RYR1 sequence analysis disclosed a novel mutation in exon 101 (c.14590T>C) and confirmed a previously reported mutation in exon 102 (c.14678G>A). Conclusions We report herein two families with CCD in whom missense mutations at the C-terminal of RYR1 were identified. Although it has been accepted that such mutations are usually associated with a severe clinical phenotype and clearly demarcated central cores, our patients exhibited a mild clinical phenotype without facial muscle involvement and skeletal deformities, and atypical cores in their muscle biopsy specimens.
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Affiliation(s)
- Na-Yeon Jung
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Yeong-Eun Park
- Department of Neurology, Pusan National University Hospital, Busan, Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Chang Hun Lee
- Department of Pathology, Pusan National University Hospital, Busan, Korea
| | - Dae-Soo Jung
- Department of Neurology, Pusan National University Hospital, Busan, Korea
| | - Dae-Seong Kim
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, Korea
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Cuperman T, Fernandes SA, Lourenço NCV, Yamamoto LU, Silva HCA, Pavanello RCM, Yamamoto GL, Zatz M, Oliveira ASB, Vainzof M. Silent polymorphisms in the RYR1 gene do not modify the phenotype of the p.4898 I>T pathogenic mutation in central core disease: a case report. BMC Res Notes 2014; 7:487. [PMID: 25084811 PMCID: PMC4124474 DOI: 10.1186/1756-0500-7-487] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Accepted: 07/25/2014] [Indexed: 12/21/2022] Open
Abstract
Background Central core disease is a congenital myopathy, characterized by presence of central core-like areas in muscle fibers. Patients have mild or moderate weakness, hypotonia and motor developmental delay. The disease is caused by mutations in the human ryanodine receptor gene (RYR1), which encodes a calcium-release channel. Since the RYR1 gene is huge, containing 106 exons, mutation screening has been limited to three ‘hot spots’, with particular attention to the C-terminal region. Recent next- generation sequencing methods are now identifying multiple numbers of variants in patients, in which interpretation and phenotype prevision is difficult. Case presentation In a Brazilian Caucasian family, clinical, histopathological and molecular analysis identified a new case of central core disease in a 48-year female. Sanger sequencing of the C-terminal region of the RYR1 gene identified two different missense mutations: c.14256 A > C polymorphism in exon 98 and c.14693 T > C in exon 102, which have already been described as pathogenic. Trans-position of the 2 mutations was confirmed because patient’s daughter, mother and sister carried only the exon 98’s mutation, a synonymous variant that was subsequently found in the frequency of 013–0,05 of alleles. Further next generation sequencing study of the whole RYR1 gene in the patient revealed the presence of additional 5 common silent polymorphisms in homozygosis and 8 polymorphisms in heterozygosis. Conclusions Considering that patient’s relatives showed no pathologic phenotype, and the phenotype presented by the patient is within the range observed in other central core disease patients with the same mutation, it was concluded that the c.14256 A > C polymorphism alone is not responsible for disease, and the associated additional silent polymorphisms are not acting as modifiers of the primary pathogenic mutation in the affected patient. The case described above illustrates the present reality where new methods for wide genome screening are becoming more accessible and able to identify a great variety of mutations and polymorphisms of unknown function in patients and their families.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Mariz Vainzof
- Laboratory of Muscle Proteins and Comparative Histopathology, Human Genome Research Center, Biosciences Institute, University of São Paulo, R, do Matão, 106 - Cidade Universitária, São Paulo, SP CEP 05508-900, Brazil.
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Rocha J, Taipa R, Melo Pires M, Oliveira J, Santos R, Santos M. Ryanodine myopathies without central cores--clinical, histopathologic, and genetic description of three cases. Pediatr Neurol 2014; 51:275-8. [PMID: 24950660 DOI: 10.1016/j.pediatrneurol.2014.04.024] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/18/2014] [Accepted: 04/24/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND Mutations in ryanodine receptor 1 gene (RYR1) are frequent causes of myopathies. They classically present with central core disease; however, clinical variability and histopathologic overlap are being increasingly recognized. PATIENTS Patient 1 is a 15-year-old girl with mild proximal, four-limb weakness from age 5, presenting with a progressive scoliosis starting at age 10. Patient 2 is an 18-year-old girl with progressively worsening muscle hypotrophy and mild proximal, four-limb weakness. She developed a rapidly progressive scoliosis from age 11 and needed surgical treatment at age 14 years. Patient 3 is an 11-year-old boy with moderate proximal limb weakness and progressive neck flexor weakness, first noticed at age 2. Muscle biopsies revealed type 1 fiber predominance (Patients 1 and 2) or abnormal type 1 fiber uniformity (Patient 3). Different RYR1 variants were identified in all patients. In Patients 1 and 3, these changes were validated as being pathogenic. CONCLUSIONS These patients illustrate early-onset, progressive myopathies with predominant axial involvement. Histopathologic findings were abnormal but not specific for a diagnosis, particularly central core myopathy. Genetic testing helped broaden the range of phenotypes included in the RYR1-related myopathies. Our patients reinforce the need to recognize the broad histopathologic variability of RYR1-related myopathies and sometimes lack of pathognomonic findings that may reduce the diagnostic threshold of this disease. We suggest that the predominance of type 1 fibers and involvement of axial muscles may be an important element to consider the RYR1 gene as candidate.
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Affiliation(s)
- João Rocha
- Department of Neurology, Hospital de Braga, Braga, Portugal.
| | - Ricardo Taipa
- Neuropathology Unit, Centro Hospitalar do Porto, Porto, Portugal
| | | | - Jorge Oliveira
- Molecular Genetics Unit, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal
| | - Rosário Santos
- Molecular Genetics Unit, Centro de Genética Médica Dr. Jacinto Magalhães, Centro Hospitalar do Porto, Porto, Portugal
| | - Manuela Santos
- Neuromuscular Diseases Unit, Department of Pediatric Neurology, Centro Hospitalar do Porto, Porto, Portugal
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Molt S, Bührdel JB, Yakovlev S, Schein P, Orfanos Z, Kirfel G, Winter L, Wiche G, van der Ven PFM, Rottbauer W, Just S, Belkin AM, Fürst DO. Aciculin interacts with filamin C and Xin and is essential for myofibril assembly, remodeling and maintenance. J Cell Sci 2014; 127:3578-92. [PMID: 24963132 DOI: 10.1242/jcs.152157] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Filamin C (FLNc) and Xin actin-binding repeat-containing proteins (XIRPs) are multi-adaptor proteins that are mainly expressed in cardiac and skeletal muscles and which play important roles in the assembly and repair of myofibrils and their attachment to the membrane. We identified the dystrophin-binding protein aciculin (also known as phosphoglucomutase-like protein 5, PGM5) as a new interaction partner of FLNc and Xin. All three proteins colocalized at intercalated discs of cardiac muscle and myotendinous junctions of skeletal muscle, whereas FLNc and aciculin also colocalized in mature Z-discs. Bimolecular fluorescence complementation experiments in developing cultured mammalian skeletal muscle cells demonstrated that Xin and aciculin also interact in FLNc-containing immature myofibrils and areas of myofibrillar remodeling and repair induced by electrical pulse stimulation (EPS). Fluorescence recovery after photobleaching (FRAP) experiments showed that aciculin is a highly dynamic and mobile protein. Aciculin knockdown in myotubes led to failure in myofibril assembly, alignment and membrane attachment, and a massive reduction in myofibril number. A highly similar phenotype was found upon depletion of aciculin in zebrafish embryos. Our results point to a thus far unappreciated, but essential, function of aciculin in myofibril formation, maintenance and remodeling.
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Affiliation(s)
- Sibylle Molt
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - John B Bührdel
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Sergiy Yakovlev
- University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Peter Schein
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | | | - Gregor Kirfel
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
| | - Lilli Winter
- Department of Biochemistry and Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | - Gerhard Wiche
- Department of Biochemistry and Molecular Cell Biology, Max F. Perutz Laboratories, University of Vienna, 1030 Vienna, Austria
| | | | - Wolfgang Rottbauer
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Steffen Just
- Department of Internal Medicine II, University of Ulm, 89081 Ulm, Germany
| | - Alexey M Belkin
- University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Dieter O Fürst
- Institute for Cell Biology, University of Bonn, 53121 Bonn, Germany
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Stathopulos PB, Seo MD, Enomoto M, Amador FJ, Ishiyama N, Ikura M. Themes and variations in ER/SR calcium release channels: structure and function. Physiology (Bethesda) 2013; 27:331-42. [PMID: 23223627 DOI: 10.1152/physiol.00013.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Calcium (Ca(2+)) release from reticular stores is a vital regulatory signal in eukaryotes. Recent structural data on large NH(2)-terminal regions of IP(3)Rs and RyRs and their tetrameric arrangement in the full-length context reveal striking mechanistic similarities in Ca(2+) release channel function. A common ancestor found in unicellular genomes underscores the fundamentality of these elements to Ca(2+) release channels.
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Affiliation(s)
- Peter B Stathopulos
- Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada
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Attali R, Aharoni S, Treves S, Rokach O, Becker Cohen M, Fellig Y, Straussberg R, Dor T, Daana M, Mitrani-Rosenbaum S, Nevo Y. Variable myopathic presentation in a single family with novel skeletal RYR1 mutation. PLoS One 2013; 8:e69296. [PMID: 23894444 DOI: 10.1371/journal.pone.0069296] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Accepted: 06/11/2013] [Indexed: 01/24/2023] Open
Abstract
We describe an autosomal recessive heterogeneous congenital myopathy in a large consanguineous family. The disease is characterized by variable severity, progressive course in 3 of 4 patients, myopathic face without ophthalmoplegia and proximal muscle weakness. Absence of cores was noted in all patients. Genome wide linkage analysis revealed a single locus on chromosome 19q13 with Zmax = 3.86 at θ = 0.0 and homozygosity of the polymorphic markers at this locus in patients. Direct sequencing of the main candidate gene within the candidate region, RYR1, was performed. A novel homozygous A to G nucleotide substitution (p.Y3016C) within exon 60 of the RYR1 gene was found in patients. ARMS PCR was used to screen for the mutation in all available family members and in an additional 150 healthy individuals. This procedure confirmed sequence analysis and did not reveal the A to G mutation (p.Y3016C) in 300 chromosomes from healthy individuals. Functional analysis on EBV immortalized cell lines showed no effect of the mutation on RyR1 pharmacological activation or the content of intracellular Ca2+ stores. Western blot analysis demonstrated a significant reduction of the RyR1 protein in the patient’s muscle concomitant with a reduction of the DHPRα1.1 protein. This novel mutation resulting in RyR1 protein decrease causes heterogeneous clinical presentation, including slow progression course and absence of centrally localized cores on muscle biopsy. We suggest that RYR1 related myopathy should be considered in a wide variety of clinical and pathological presentation in childhood myopathies.
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Brandom BW, Bina S, Wong CA, Wallace T, Visoiu M, Isackson PJ, Vladutiu GD, Sambuughin N, Muldoon SM. Ryanodine receptor type 1 gene variants in the malignant hyperthermia-susceptible population of the United States. Anesth Analg 2013; 116:1078-1086. [PMID: 23558838 PMCID: PMC3633164 DOI: 10.1213/ane.0b013e31828a71ff] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Mutations in the ryanodine receptor type 1 gene (RYR1) that encodes the skeletal muscle-specific intracellular calcium (Ca(2+)) release channel are a cause of malignant hyperthermia (MH). In this study, we examined RYR1 mutations in a large number of North American MH-susceptible (MHS) subjects without prior genetic diagnosis. METHODS RYR1 was examined in 120 unrelated MHS subjects from the United States in a tiered manner. The α-1 subunit of the dihydropyridine receptor gene (CACNA1S) was screened for 4 variants in subjects in whom no abnormality was found in ≥ 100 exons of RYR1. RESULTS Ten known causative MH mutations were found in 26 subjects. Variants of uncertain significance in RYR1 were found in 36 subjects, 16 of which are novel. Novel variants in both RYR1 and CACNA1S were found in the 1 subject who died of MH. Two RYR1 variants were found in 4 subjects. Variants of uncertain significance were found outside and inside the hotspots of RYR1. Maximal contractures in the caffeine-halothane contracture test were greater in those who had a known MH mutation or variant of uncertain significance in RYR1 than in those who did not. CONCLUSIONS The identification of novel RYR1 variants and previously observed RYR1 variants of uncertain significance in independent MHS families is necessary for demonstrating the significance of these variants for MH susceptibility and supports the need for functional studies of these variants. Continued reporting of the clinical phenotypes of MH is necessary for interpretation of genetic findings, especially because the pathogenicity of most of these genetic variants associated with MHS remains to be elucidated.
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Affiliation(s)
- Barbara W Brandom
- From the Department of Anesthesiology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; Department of Anesthesiology, Uniformed Services University of the Health Sciences, Bethesda, Maryland; Department of Anesthesiology, Northwestern University, Chicago, Illinois; Children's Hospital, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania; and Departments of Pediatrics, Neurology, Pathology and Anatomical Sciences, School of Medicine and Biomedical Sciences, State University of New York at Buffalo, Buffalo, New York
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Bharucha-Goebel DX, Santi M, Medne L, Zukosky K, Zukosky K, Dastgir J, Shieh PB, Winder T, Tennekoon G, Finkel RS, Dowling JJ, Monnier N, Bönnemann CG. Severe congenital RYR1-associated myopathy: the expanding clinicopathologic and genetic spectrum. Neurology 2013; 80:1584-9. [PMID: 23553484 DOI: 10.1212/wnl.0b013e3182900380] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE To report a series of 11 patients on the severe end of the spectrum of ryanodine receptor 1 (RYR1) gene-related myopathy, in order to expand the clinical, histologic, and genetic heterogeneity associated with this group of patients. METHODS Eleven patients evaluated in the neonatal period with severe neonatal-onset RYR1-associated myopathy confirmed by genetic testing were ascertained. Clinical features, molecular testing results, muscle imaging, and muscle histology are reviewed. RESULTS Clinical features associated with the severe neonatal presentation of RYR1-associated myopathy included decreased fetal movement, hypotonia, poor feeding, respiratory involvement, arthrogryposis, and ophthalmoplegia in 3 patients, and femur fractures or hip dislocation at birth. Four patients had dominant RYR1 mutations, and 7 had recessive RYR1 mutations. One patient had a cleft palate, and another a congenital rigid spine phenotype-findings not previously described in the literature in patients with early-onset RYR1 mutations. Six patients who underwent muscle ultrasound showed relative sparing of the rectus femoris muscle. Histologically, all patients with dominant mutations had classic central cores on muscle biopsy. Patients with recessive mutations showed great histologic heterogeneity, including fibrosis, variation in fiber size, skewed fiber typing, very small fibers, and nuclear internalization with or without ill-defined cores. CONCLUSIONS This series confirms and expands the clinical and histologic variability associated with severe congenital RYR1-associated myopathy. Both dominant and recessive mutations of the RYR1 gene can result in a severe neonatal-onset phenotype, but more clinical and histologic heterogeneity has been seen in those with recessive RYR1 gene mutations. Central cores are not obligatory histologic features in recessive RYR1 mutations. Sparing of the rectus femoris muscle on imaging should prompt evaluation for RYR1-associated myopathy in the appropriate clinical context.
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Amador FJ, Stathopulos PB, Enomoto M, Ikura M. Ryanodine receptor calcium release channels: lessons from structure-function studies. FEBS J 2013; 280:5456-70. [PMID: 23413940 DOI: 10.1111/febs.12194] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Revised: 01/24/2013] [Accepted: 02/04/2013] [Indexed: 11/28/2022]
Abstract
Ryanodine receptors (RyRs) are the largest known ion channels. They are Ca(2+) release channels found primarily on the sarcoplasmic reticulum of myocytes. Several hundred mutations in RyRs are associated with skeletal or cardiomyocyte disease in humans. Many of these mutations can now be mapped onto the high resolution structures of individual RyR domains and on full-length tetrameric cryo-electron microscopy structures. A closely related Ca(2+) release channel, the inositol 1,4,5-trisphospate receptor (IP3 R), shows a conserved structural architecture at the N-terminus, suggesting that both channels evolved from an ancestral unicellular RyR/IP3 R. The functional insights provided by recent structural studies for both channels will aid in the development of rationale treatments for a myriad of Ca(2+)-signaled malignancies.
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Affiliation(s)
- Fernando J Amador
- Ontario Cancer Institute and Department of Medical Biophysics, University of Toronto, Canada
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Maggi L, Scoto M, Cirak S, Robb SA, Klein A, Lillis S, Cullup T, Feng L, Manzur AY, Sewry CA, Abbs S, Jungbluth H, Muntoni F. Congenital myopathies--clinical features and frequency of individual subtypes diagnosed over a 5-year period in the United Kingdom. Neuromuscul Disord 2013; 23:195-205. [PMID: 23394784 DOI: 10.1016/j.nmd.2013.01.004] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Revised: 11/15/2012] [Accepted: 01/03/2013] [Indexed: 12/14/2022]
Abstract
The congenital myopathies are a group of inherited neuromuscular disorders mainly defined on the basis of characteristic histopathological features. We analysed 66 patients assessed at a single centre over a 5 year period. Of the 54 patients where muscle biopsy was available, 29 (54%) had a core myopathy (central core disease, multi-minicore disease), 9 (17%) had nemaline myopathy, 7 (13%) had myotubular/centronuclear myopathy, 2 (4%) had congenital fibre type disproportion, 6 (11%) had isolated type 1 predominance and 1 (2%) had a mixed core-rod myopathy. Of the 44 patients with a genetic diagnosis, RYR1 was mutated in 26 (59%), ACTA1 in 7 (16%), SEPN1 in 7 (16%), MTM1 in 2 (5%), NEB in 1 (2%) and TPM3 in 1 (2%). Clinically, 77% of patients older than 18 months could walk independently. 35% of all patients required ventilatory support and/or enteral feeding. Clinical course was stable or improved in 57/66 (86%) patients, whilst 4 (6%) got worse and 5 (8%) died. These findings indicate that core myopathies are the most common form of congenital myopathies and that more than half can be attributed to RYR1 mutations. The underlying genetic defect remains to be identified in 1/3 of congenital myopathies cases.
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Affiliation(s)
- L Maggi
- Dubowitz Neuromuscular Centre, UCL Institute of Child Health & Great Ormond Street Hospital for Children Foundation Trust, London, UK
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Nowak KJ, Ravenscroft G, Laing NG. Skeletal muscle α-actin diseases (actinopathies): pathology and mechanisms. Acta Neuropathol 2013; 125:19-32. [PMID: 22825594 DOI: 10.1007/s00401-012-1019-z] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 07/12/2012] [Indexed: 01/18/2023]
Abstract
Mutations in the skeletal muscle α-actin gene (ACTA1) cause a range of congenital myopathies characterised by muscle weakness and specific skeletal muscle structural lesions. Actin accumulations, nemaline and intranuclear bodies, fibre-type disproportion, cores, caps, dystrophic features and zebra bodies have all been seen in biopsies from patients with ACTA1 disease, with patients frequently presenting with multiple pathologies. Therefore increasingly it is considered that these entities may represent a continuum of structural abnormalities arising due to ACTA1 mutations. Recently an ACTA1 mutation has also been associated with a hypertonic clinical presentation with nemaline bodies. Whilst multiple genes are known to cause many of the pathologies associated with ACTA1 mutations, to date actin aggregates, intranuclear rods and zebra bodies have solely been attributed to ACTA1 mutations. Approximately 200 different ACTA1 mutations have been identified, with 90 % resulting in dominant disease and 10 % resulting in recessive disease. Despite extensive research into normal actin function and the functional consequences of ACTA1 mutations in cell culture, animal models and patient tissue, the mechanisms underlying muscle weakness and the formation of structural lesions remains largely unknown. Whilst precise mechanisms are being grappled with, headway is being made in terms of developing therapeutics for ACTA1 disease, with gene therapy (specifically reducing the proportion of mutant skeletal muscle α-actin protein) and pharmacological agents showing promising results in animal models and patient muscle. The use of small molecules to sensitise the contractile apparatus to Ca(2+) is a promising therapeutic for patients with various neuromuscular disorders, including ACTA1 disease.
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Kraeva N, Zvaritch E, Rossi AE, Goonasekera SA, Zaid H, Frodis W, Kraev A, Dirksen RT, Maclennan DH, Riazi S. Novel excitation-contraction uncoupled RYR1 mutations in patients with central core disease. Neuromuscul Disord 2012. [PMID: 23183335 DOI: 10.1016/j.nmd.2012.08.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Central core disease, one of the most common congenital myopathies in humans, has been linked to mutations in the RYR1 gene encoding the Ca(2+) release channel of the sarcoplasmic reticulum (RyR1). Functional analyses showed that disease-associated RYR1 mutations led to impairment of skeletal muscle Ca(2+) homeostasis; however, thorough understanding of the molecular mechanisms underlying central core disease and other RyR1-related conditions is still lacking. We screened by sequencing the complete RYR1 transcripts in ten unrelated patients with central core disease and identified five novel, p.M4640R, p.L4647P, p.F4808L, p.D4918N and p.F4941C, and four recurrent mutations. Four of the novel mutations involved amino acid residues that were positioned within putative transmembrane segments of the RyR1. The pathogenic character of the identified mutations was demonstrated by bioinformatic analyses and by the in vitro functional studies in HEK293 cells and RYR1-null (dyspedic) myotubes. Characterization of Ca(2+) channel properties of RyR1s carrying one recurrent and two novel mutations upholds the view that diminished intracellular Ca(2+) release caused by impaired Ca(2+) channel gating and/or Ca(2+) permeability is an important component of central core disease etiology. This study expands the list of functionally characterized disease-associated RyR1 mutations, increasing the value of genetic diagnosis for RyR1-related disorders.
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Affiliation(s)
- Natalia Kraeva
- Malignant Hyperthermia Investigation Unit, Toronto General Hospital, University Health Network, Toronto, ON, Canada M5G 2C4
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Abstract
Congenital myopathy is a clinicopathological concept of characteristic histopathological findings on muscle biopsy in a patient with early-onset weakness. Three main categories are recognized within the classical congenital myopathies: nemaline myopathy, core myopathy, and centronuclear myopathy. Recent evidence of overlapping clinical and histological features between the classical forms and their different genetic entities suggests that there may be shared pathomechanisms between the congenital myopathies. Animal models, especially mouse and zebrafish, have been especially helpful in elucidating such pathomechanisms associated with the congenital myopathies and provide models in which future therapies can be investigated.
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Affiliation(s)
- Jessica R Nance
- Department of Neurology, Children's National Medical Center, Washington, DC 20010, USA
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Abstract
Neuromuscular disorders affect the peripheral nervous system and muscle. The principle effect of neuromuscular disorders is therefore on the ability to perform voluntary movements. Neuromuscular disorders cause significant incapacity, including, at the most extreme, almost complete paralysis. Neuromuscular diseases include some of the most devastating disorders that afflict mankind, for example motor neuron disease. Neuromuscular diseases have onset any time from in utero until old age. They are most often genetic. The last 25 years has been the golden age of genetics, with the disease genes responsible for many genetic neuromuscular disorders now identified. Neuromuscular disorders may be inherited as autosomal dominant, autosomal recessive, or X-linked traits. They may also result from mutations in mitochondrial DNA or from de novo mutations not present in the peripheral blood DNA of either parent. The high incidence of de novo mutation has been one of the surprises of the recent increase in information about the genetics of neuromuscular disorders. The disease burden imposed on families is enormous including decision making in relation to presymptomatic diagnosis for late onset neurodegenerative disorders and reproductive choices. Diagnostic molecular neurogenetics laboratories have been faced with an ever-increasing range of disease genes that could be tested for and usually a finite budget with which to perform the possible testing. Neurogenetics has moved from one known disease gene, the Duchenne muscular dystrophy gene in July 1987, to hundreds of disease genes in 2011. It can be anticipated that with the advent of next generation sequencing (NGS), most, if not all, causative genes will be identified in the next few years. Any type of mutation possible in human DNA has been shown to cause genetic neuromuscular disorders, including point mutations, small insertions and deletions, large deletions and duplications, repeat expansions or contraction and somatic mosaicism. The diagnostic laboratory therefore has to be capable of a large number of techniques in order to identify the different mutation types and requires highly skilled staff. Mutations causing neuromuscular disorders affect the largest human proteins for example titin and nebulin. Successful molecular diagnosis can make invasive and expensive diagnostic procedures such as muscle biopsy unnecessary. Molecular diagnosis is currently largely based on Sanger sequencing, which at most can sequence a small number of exons in one gene at a time. NGS techniques will facilitate molecular diagnostics, but not for all types of mutations. For example, NGS is not good at identifying repeat expansions or copy number variations. Currently, diagnostic molecular neurogenetics is focused on identifying the causative mutation(s) in a patient. In the future, the focus might move to prevention, by identifying carriers of recessive diseases before they have affected children. The pathobiology of many of the diseases remains obscure, as do factors affecting disease severity. The aim of this review is to describe molecular diagnosis of genetic neuromuscular disorders in the past, the present and speculate on the future.
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Affiliation(s)
- Nigel G Laing
- Centre for Medical Research, University of Western Australia, Western Australian Institute for Medical Research, Nedlands, Western Australia, Australia.
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Klein A, Lillis S, Munteanu I, Scoto M, Zhou H, Quinlivan R, Straub V, Manzur AY, Roper H, Jeannet PY, Rakowicz W, Jones DH, Jensen UB, Wraige E, Trump N, Schara U, Lochmuller H, Sarkozy A, Kingston H, Norwood F, Damian M, Kirschner J, Longman C, Roberts M, Auer-Grumbach M, Hughes I, Bushby K, Sewry C, Robb S, Abbs S, Jungbluth H, Muntoni F. Clinical and genetic findings in a large cohort of patients with ryanodine receptor 1 gene-associated myopathies. Hum Mutat 2012; 33:981-8. [PMID: 22473935 DOI: 10.1002/humu.22056] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2011] [Accepted: 02/07/2012] [Indexed: 11/12/2022]
Abstract
Ryanodine receptor 1 (RYR1) mutations are a common cause of congenital myopathies associated with both dominant and recessive inheritance. Histopathological findings frequently feature central cores or multi-minicores, more rarely, type 1 predominance/uniformity, fiber-type disproportion, increased internal nucleation, and fatty and connective tissue. We describe 71 families, 35 associated with dominant RYR1 mutations and 36 with recessive inheritance. Five of the dominant mutations and 35 of the 55 recessive mutations have not been previously reported. Dominant mutations, typically missense, were frequently located in recognized mutational hotspot regions, while recessive mutations were distributed throughout the entire coding sequence. Recessive mutations included nonsense and splice mutations expected to result in reduced RyR1 protein. There was wide clinical variability. As a group, dominant mutations were associated with milder phenotypes; patients with recessive inheritance had earlier onset, more weakness, and functional limitations. Extraocular and bulbar muscle involvement was almost exclusively observed in the recessive group. In conclusion, our study reports a large number of novel RYR1 mutations and indicates that recessive variants are at least as frequent as the dominant ones. Assigning pathogenicity to novel mutations is often difficult, and interpretation of genetic results in the context of clinical, histological, and muscle magnetic resonance imaging findings is essential.
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Affiliation(s)
- Andrea Klein
- Paediatric Neurology, University Children's Hospital Zurich, Zurich, Switzerland
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Abstract
The core myopathies, Central Core Disease and Multiminicore Disease, are heterogeneous congenital myopathies with the common defining histopathological feature of focally reduced oxidative enzyme activity (central cores, multiminicores). Mutations in the gene encoding for the skeletal muscle ryanodine (RyR1) receptor are the most common cause. Mutations in the selenoprotein N (SEPN1) gene cause a less common variant. Pathogenic mechanisms underlying dominant RYR1 mutations have been extensively characterized, whereas those associated with recessive RYR1 and SEPN1 mutations are emerging. Identifying a specific genetic defect from the histopathological diagnosis of a core myopathy is complex and ought to be informed by a combined appraisal of histopathological, clinical, and, increasingly, muscle magnetic resonance imaging data. The present review aims at giving an overview of the main genetic and clinicopathological findings, with a major emphasis on features likely to inform the diagnostic process, as well as current treatments and perspectives for future research.
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Affiliation(s)
- Heinz Jungbluth
- Clinical Neuroscience Division, Institute of Psychiatry, King's College London, London, UK.
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Affiliation(s)
- Suzanne Lillis
- GSTS Pathology, Guy's Hospital, Great Maze Pond, London, UK
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Duarte ST, Oliveira J, Santos R, Pereira P, Barroso C, Conceição I, Evangelista T. Dominant and recessive RYR1 mutations in adults with core lesions and mild muscle symptoms. Muscle Nerve 2011; 44:102-8. [PMID: 21674524 DOI: 10.1002/mus.22009] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Ryanodine receptor gene (RYR1) mutations have been associated with central core disease (CCD), multiminicore/minicore/multicore disease (MmD), and susceptibility to malignant hyperthermia (MH). METHODS Patients with muscle symptoms in adulthood, who had features compatible with CCD/MmD, underwent clinical, histological, and genetic (RYR1 and SEPN1 genes) evaluations. Published cases of CCD and MmD with adult onset were also reviewed. RESULTS Eight patients fulfilled the criteria for further analysis. Five RYR1 mutations, 4 of them unreported, were detected in 3 patients. Compound heterozygosity was proven in 1 case. CONCLUSIONS To our knowledge, this is the only report of adult onset associated with recessive RYR1 mutations and central core/multiminicores on muscle biopsy. Although adult patients with CCD, MmD, and minimally symptomatic MH with abnormal muscle biopsy findings usually have a mild clinical course, differential diagnosis and carrier screening is crucial for prevention of potentially life-threatening reactions to general anesthesia.
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Affiliation(s)
- Sofia T Duarte
- Neuropaediatrics Department, Hospital de D. Estefânia, Centro Hospitalar de Lisboa Central, E.P.E., Rua Jacinta Marto, 1169-045 Lisboa, Portugal.
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Bevilacqua JA, Monnier N, Bitoun M, Eymard B, Ferreiro A, Monges S, Lubieniecki F, Taratuto AL, Laquerrière A, Claeys KG, Marty I, Fardeau M, Guicheney P, Lunardi J, Romero NB. Recessive RYR1 mutations cause unusual congenital myopathy with prominent nuclear internalization and large areas of myofibrillar disorganization. Neuropathol Appl Neurobiol 2011; 37:271-84. [PMID: 21062345 DOI: 10.1111/j.1365-2990.2010.01149.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS To report the clinical, pathological and genetic findings in a group of patients with a previously not described phenotype of congenital myopathy due to recessive mutations in the gene encoding the type 1 muscle ryanodine receptor channel (RYR1). METHODS Seven unrelated patients shared a predominant axial and proximal weakness of varying severity, with onset during the neonatal period, associated with bilateral ptosis and ophthalmoparesis, and unusual muscle biopsy features at light and electron microscopic levels. RESULTS Muscle biopsy histochemistry revealed a peculiar morphological pattern characterized by numerous internalized myonuclei in up to 51% of fibres and large areas of myofibrillar disorganization with undefined borders. Ultrastructurally, such areas frequently occupied the whole myofibre cross section and extended to a moderate number of sarcomeres in length. Molecular genetic investigations identified recessive mutations in the ryanodine receptor (RYR1) gene in six compound heterozygous patients and one homozygous patient. Nine mutations are novel and four have already been reported either as pathogenic recessive mutations or as changes affecting a residue associated with dominant malignant hyperthermia susceptibility. Only two mutations were located in the C-terminal transmembrane domain whereas the others were distributed throughout the cytoplasmic region of RyR1. CONCLUSION Our data enlarge the spectrum of RYR1 mutations and highlight their clinical and morphological heterogeneity. A congenital myopathy featuring ptosis and external ophthalmoplegia, concomitant with the novel histopathological phenotype showing fibres with large, poorly delimited areas of myofibrillar disorganization and internal nuclei, is highly suggestive of an RYR1-related congenital myopathy.
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Affiliation(s)
- J A Bevilacqua
- Institut de Myologie, Unité de Morphologie Neuromusculaire, Groupe Hospitalier-Universitaire Pitié-Salpêtrière, Paris, France
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MacLennan DH, Zvaritch E. Mechanistic models for muscle diseases and disorders originating in the sarcoplasmic reticulum. Biochimica et Biophysica Acta (BBA) - Molecular Cell Research 2011; 1813:948-64. [DOI: 10.1016/j.bbamcr.2010.11.009] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 11/11/2010] [Accepted: 11/18/2010] [Indexed: 11/29/2022]
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