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Ibarra Moreno CA, Silva HCA, Voermans NC, Jungbluth H, van den Bersselaar LR, Rendu J, Cieniewicz A, Hopkins PM, Riazi S. Myopathic manifestations across the adult lifespan of patients with malignant hyperthermia susceptibility: a narrative review. Br J Anaesth 2024:S0007-0912(24)00419-7. [PMID: 39107166 DOI: 10.1016/j.bja.2024.05.046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 05/27/2024] [Accepted: 05/29/2024] [Indexed: 08/09/2024] Open
Abstract
Malignant hyperthermia susceptibility (MHS) designates individuals at risk of developing a hypermetabolic reaction triggered by halogenated anaesthetics or the depolarising neuromuscular blocking agent suxamethonium. Over the past few decades, beyond the operating theatre, myopathic manifestations impacting daily life are increasingly recognised as a prevalent phenomenon in MHS patients. At the request of the European Malignant Hyperthermia Group, we reviewed the literature and gathered the opinion of experts to define MHS-related myopathy as a distinct phenotype expressed across the adult lifespan of MHS patients unrelated to anaesthetic exposure; this serves to raise awareness about non-anaesthetic manifestations, potential therapies, and management of MHS-related myopathy. We focused on the clinical presentation, biochemical and histopathological findings, and the impact on patient well-being. The spectrum of symptoms of MHS-related myopathy encompasses muscle cramps, stiffness, myalgias, rhabdomyolysis, and weakness, with a wide age range of onset mainly during adulthood. Histopathological analysis can reveal nonspecific abnormalities suggestive of RYR1 involvement, while metabolic profiling reflects altered energy metabolism in MHS muscle. Myopathic manifestations can significantly impact patient quality of life and lead to functional limitations and socio-economic burden. While currently available therapies can provide symptomatic relief, there is a need for further research into targeted treatments addressing the underlying pathophysiology. Counselling early after establishing the MHS diagnosis, followed by multidisciplinary management involving various medical specialties, is crucial to optimise patient care.
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Affiliation(s)
- Carlos A Ibarra Moreno
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Management, University Health Network, Toronto, ON, Canada
| | - Helga C A Silva
- Malignant Hyperthermia Unit, Department of Anesthesiology, Pain and Intensive Care, Federal University of São Paulo, São Paulo, Brazil
| | - Nicol C Voermans
- Department of Neurology, Radboudumc Research Institute for Medical Innovation, Nijmegen, The Netherlands
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina London Children's Hospital, Guy's and St. Thomas' Hospital NHS Foundation Trust, London, UK; Randall Centre for Cell and Molecular Biophysics, Muscle Signalling Section, Faculty of Life Sciences and Medicine (FoLSM), King's College London, London, UK
| | - Luuk R van den Bersselaar
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology, Canisius Wilhelmina Hospital, Nijmegen, The Netherlands; Department of Anesthesiology, Pain and Palliative Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - John Rendu
- Universite Grenoble Alpes, INSERM, Grenoble Institut Neurosciences, U1216, CHU Grenoble Alpes, Grenoble, France
| | - Agnieszka Cieniewicz
- Department of Anaesthesiology and Intensive Therapy, Institute of Tuberculosis and Lung Diseases, Warsaw, Poland
| | - Philip M Hopkins
- Leeds Institute of Medical Research at St James's, University of Leeds, Leeds, UK; Department of Anaesthesia, St James's University Hospital, Leeds Teaching Hospitals, NHS Trust, Leeds, UK
| | - Sheila Riazi
- Malignant Hyperthermia Investigation Unit, Department of Anesthesiology and Pain Management, University Health Network, Toronto, ON, Canada.
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2
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Gineste C, Laporte J. Therapeutic approaches in different congenital myopathies. Curr Opin Pharmacol 2023; 68:102328. [PMID: 36512981 DOI: 10.1016/j.coph.2022.102328] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/17/2022] [Accepted: 11/12/2022] [Indexed: 12/14/2022]
Abstract
Congenital myopathies are rare and severe genetic diseases affecting the skeletal muscle function in children and adults. They present a variable spectrum of phenotypes and a genetic heterogeneity. Subgroups are defined according to the clinical and histopathological features and encompass core myopathy, centronuclear myopathy, nemaline myopathy and other rare congenital myopathies. No approved treatment exists to date for any congenital myopathies. To tackle this important unmet need, an increased number of proof-of-concept studies recently assessed the therapeutic potential of various strategies, either pharmacological or genetic-based, aiming at counteracting muscle weakness or/and cure the pathology. Here, we list the implicated genes and cellular pathways, and review the therapeutic approaches preclinically tested and the ongoing/completed clinical trials for the different types of congenital myopathies.
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Affiliation(s)
- Charlotte Gineste
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm U1258, Cnrs UMR7104, Strasbourg University, Illkirch 67404, France
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm U1258, Cnrs UMR7104, Strasbourg University, Illkirch 67404, France.
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3
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O’Connor TN, van den Bersselaar LR, Chen YS, Nicolau S, Simon B, Huseth A, Todd JJ, Van Petegem F, Sarkozy A, Goldberg MF, Voermans NC, Dirksena RT. RYR-1-Related Diseases International Research Workshop: From Mechanisms to Treatments Pittsburgh, PA, U.S.A., 21-22 July 2022. J Neuromuscul Dis 2023; 10:135-154. [PMID: 36404556 PMCID: PMC10023165 DOI: 10.3233/jnd-221609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- Thomas N. O’Connor
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
| | - Luuk R. van den Bersselaar
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
- Malignant Hyperthermia Investigation Unit, Department of Anaesthesia, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands
| | - Yu Seby Chen
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Stefan Nicolau
- Center for Gene Therapy, Nationwide Children’s Hospital, Columbus, OH, USA
| | | | | | - Joshua J. Todd
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, The Life Sciences Institute, The University of British Columbia, Vancouver, BC, Canada
| | - Anna Sarkozy
- The Dubowitz Neuromuscular Centre, Institute of Child Health and Great Ormond Street Hospital for Children, London, UK
| | | | - Nicol C. Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Robert T. Dirksena
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, Rochester, NY, USA
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Topaloglu H. Core myopathies - a short review. ACTA MYOLOGICA : MYOPATHIES AND CARDIOMYOPATHIES : OFFICIAL JOURNAL OF THE MEDITERRANEAN SOCIETY OF MYOLOGY 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] [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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5
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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: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [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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6
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Adaikina A, Hofman PL, O'Grady GL, Gusso S. Exercise Training as Part of Musculoskeletal Management for Congenital Myopathy: Where Are We Now? Pediatr Neurol 2020; 104:13-18. [PMID: 31926608 DOI: 10.1016/j.pediatrneurol.2019.10.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 09/19/2019] [Accepted: 10/22/2019] [Indexed: 01/02/2023]
Abstract
Congenital myopathy is a heterogeneous group of muscle disorders characterized by muscle weakness and hypotonia. This condition is associated with a range of skeletal, respiratory, and ophthalmologic complications and requires a multidisciplinary therapeutic approach aimed at maximizing the function and independence of patients. One promising direction for therapeutic intervention is physical exercise rehabilitation, given its demonstrated ability to promote muscle and bone health of patients with a variety of neuromuscular conditions. However, there are few data to assist health care professionals identify the optimal physical activity levels and exercise type, including the intensity, frequency, and duration. This lack of empirical evidence is particularly problematic given the fact that inappropriate exercise modes can potentially cause muscle damage in patients with congenital myopathy. In this article, we discuss the rationale behind the incorporation of two types of physical exercises, strength and aerobic training, into the clinical care of patients with congenital myopathy. Given the paucity of literature on the management of congenital myopathy, we review the results of published research on the treatment of both congenital myopathy and other neuromuscular diseases that could provide helpful insights into the physical rehabilitation of patients with congenital myopathy. We also discuss the potential benefits of vibration therapy, which has been studied in patients with other neuromuscular disorders over the last two decades. We conclude by proposing directions for future research on physical rehabilitation of patients with congenital myopathy.
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Affiliation(s)
- Alena Adaikina
- Liggins Institute, University of Auckland, Auckland, New Zealand.
| | - Paul L Hofman
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Gina L O'Grady
- Paediatric Neurology Department, Starship Children's Hospital, Auckland, New Zealand
| | - Silmara Gusso
- Department of Exercise Sciences, University of Auckland, Auckland, New Zealand
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McMacken GM, Spendiff S, Whittaker RG, O’Connor E, Howarth RM, Boczonadi V, Horvath R, Slater CR, Lochmüller H. Salbutamol modifies the neuromuscular junction in a mouse model of ColQ myasthenic syndrome. Hum Mol Genet 2019; 28:2339-2351. [PMID: 31220253 PMCID: PMC6606850 DOI: 10.1093/hmg/ddz059] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Revised: 03/14/2019] [Accepted: 03/15/2019] [Indexed: 12/23/2022] Open
Abstract
The β-adrenergic agonists salbutamol and ephedrine have proven to be effective as therapies for human disorders of the neuromuscular junction, in particular many subsets of congenital myasthenic syndromes. However, the mechanisms underlying this clinical benefit are unknown and improved understanding of the effect of adrenergic signalling on the neuromuscular junction is essential to facilitate the development of more targeted therapies. Here, we investigated the effect of salbutamol treatment on the neuromuscular junction in the ColQ deficient mouse, a model of end-plate acetylcholinesterase deficiency. ColQ-/- mice received 7 weeks of daily salbutamol injection, and the effect on muscle strength and neuromuscular junction morphology was analysed. We show that salbutamol leads to a gradual improvement in muscle strength in ColQ-/- mice. In addition, the neuromuscular junctions of salbutamol treated mice showed significant improvements in several postsynaptic morphological defects, including increased synaptic area, acetylcholine receptor area and density, and extent of postjunctional folds. These changes occurred without alterations in skeletal muscle fibre size or type. These findings suggest that β-adrenergic agonists lead to functional benefit in the ColQ-/- mouse and to long-term structural changes at the neuromuscular junction. These effects are primarily at the postsynaptic membrane and may lead to enhanced neuromuscular transmission.
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Affiliation(s)
- Grace M McMacken
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | - Sally Spendiff
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - Roger G Whittaker
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK
| | - Emily O’Connor
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | - Rachel M Howarth
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle Upon Tyne, UK
| | - Veronika Boczonadi
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Clarke R Slater
- Institute of Neuroscience, Newcastle University, Newcastle Upon Tyne, UK
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center – University of Freiburg, Faculty of Medicine, Freiburg, Germany
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada
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8
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Frongia AL, Natera-de Benito D, Ortez C, Alarcón M, Borrás A, Medina J, Vigo M, Padrós N, Moya O, Armas J, Carrera-García L, Expósito-Escudero J, Cuadras D, Bernal S, Martorell L, Colomer J, Nascimento A. Salbutamol tolerability and efficacy in patients with spinal muscular atrophy type II. Neuromuscul Disord 2019; 29:517-524. [PMID: 31201046 DOI: 10.1016/j.nmd.2019.04.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Revised: 02/25/2019] [Accepted: 04/05/2019] [Indexed: 12/01/2022]
Abstract
Spinal muscular atrophy (SMA) is an autosomal recessive disease caused by homozygous deletions or loss-of-function mutations in SMN1, which result in a degeneration of motor neurons in the spinal cord and brain stem. Even without a randomized placebo-controlled trial, salbutamol has been offered to patients with SMA in the neuromuscular clinics of most of hospitals for many years. We describe the response to salbutamol in 48 patients with SMA type II who were not taking any other medication. We investigate the changes over an eighteen-month period in motor functional scales and we analyze side effects and subjective response to treatment. Our results suggest that oral administration of salbutamol might be helpful in the maintenance of motor function in patients with SMA type II. An apparent beneficial effect was observed in functional scales of children under the age of 6, especially during the first 6 months of therapy. The majority of patients of all ages referred some kind of subjective positive effect associated with therapy intake. Salbutamol seemed safe and was well tolerated without serious side effects.
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Affiliation(s)
- A L Frongia
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - D Natera-de Benito
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain.
| | - C Ortez
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - M Alarcón
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain
| | - A Borrás
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - J Medina
- Department of Rehabilitation and Physical Medicine, Hospital Sant Joan de Deu, Barcelona, Spain
| | - M Vigo
- Department of Rehabilitation and Physical Medicine, Hospital Sant Joan de Deu, Barcelona, Spain
| | - N Padrós
- Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - O Moya
- Department of Rehabilitation and Physical Medicine, Hospital Sant Joan de Deu, Barcelona, Spain
| | - J Armas
- Department of Rehabilitation and Physical Medicine, Hospital Sant Joan de Deu, Barcelona, Spain
| | - L Carrera-García
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - J Expósito-Escudero
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - D Cuadras
- Statistics Department, Fundacio Sant Joan de Deu, Barcelona, Spain
| | - S Bernal
- Department of Genetics, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain
| | - L Martorell
- Department of Genetics, Hospital Sant Joan de Deu, Barcelona, Spain
| | - J Colomer
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
| | - A Nascimento
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Universitari Sant Joan de Deu, Barcelona, Spain; Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Spain
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Abstract
The congenital myopathies are a genetically heterogeneous and diverse group of early-onset, nondystrophic neuromuscular disorders. While the originally reported "classical" entities within this group - Central Core Disease, Multiminicore Disease, Nemaline Myopathy, and Centronuclear Myopathy - were defined by the predominant finding on muscle biopsy, "novel" forms with multiple, subtle, and unusual histopathologic features have been described more recently, reflective of an expanding phenotypical spectrum. The main disease mechanisms concern excitation-contraction coupling, intracellular calcium homeostasis, and thin/thick filament interactions. Management to date has been mainly supportive. Therapeutic strategies currently at various stages of exploration include genetic interventions aimed at direct correction of the underlying genetic defect, enzyme replacement therapy, and pharmacologic approaches, either specifically targeting the principal effect of the underlying gene mutation, or addressing its downstream consequences more generally. Clinical trial development is accelerating but will require more robust natural history data and tailored outcome measures.
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Affiliation(s)
- Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's and St. Thomas' Hospital NHS Foundation Trust, London, United Kingdom; Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section, London, United Kingdom; Department of Basic and Clinical Neuroscience, IoPPN, King's College, London, United Kingdom.
| | - Francesco Muntoni
- The Dubowitz Neuromuscular Centre, Developmental Neurosciences Programme, UCL Great Ormond Street Institute of Child Health & Great Ormond Street Hospital for Children, London, United Kingdom; NIHR Great Ormond Street Hospital Biomedical Research Centre, London, United Kingdom
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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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11
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Gonorazky HD, Bönnemann CG, Dowling JJ. The genetics of congenital myopathies. HANDBOOK OF CLINICAL NEUROLOGY 2018; 148:549-564. [PMID: 29478600 DOI: 10.1016/b978-0-444-64076-5.00036-3] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Congenital myopathies are a clinically and genetically heterogeneous group of conditions that most commonly present at or around the time of birth with hypotonia, muscle weakness, and (often) respiratory distress. Historically, this group of disorders has been subclassified based on muscle histopathologic characteristics. There has been an explosion of gene discovery, and there are now at least 32 different genetic causes of disease. With this increased understanding of the genetic basis of disease has come the knowledge that the mutations in congenital myopathy genes can present with a wide variety of clinical phenotypes and can result in a broad spectrum of histopathologic findings on muscle biopsy. In addition, mutations in several genes can share the same histopathologic features. The identification of new genes and interpretation of different pathomechanisms at a molecular level have helped us to understand the clinical and histopathologic similarities that this group of disorders share. In this review, we highlight the genetic understanding for each subtype, its pathogenesis, and the future key issues in congenital myopathies.
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Affiliation(s)
- Hernan D Gonorazky
- Division of Neurology and Program of Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON, Canada
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD, United States
| | - James J Dowling
- Division of Neurology and Program of Genetics and Genome Biology, Hospital for Sick Children, Toronto, ON, Canada.
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12
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Dowling JJ, D. Gonorazky H, Cohn RD, Campbell C. Treating pediatric neuromuscular disorders: The future is now. Am J Med Genet A 2018; 176:804-841. [PMID: 28889642 PMCID: PMC5900978 DOI: 10.1002/ajmg.a.38418] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 07/31/2017] [Indexed: 12/12/2022]
Abstract
Pediatric neuromuscular diseases encompass all disorders with onset in childhood and where the primary area of pathology is in the peripheral nervous system. These conditions are largely genetic in etiology, and only those with a genetic underpinning will be presented in this review. This includes disorders of the anterior horn cell (e.g., spinal muscular atrophy), peripheral nerve (e.g., Charcot-Marie-Tooth disease), the neuromuscular junction (e.g., congenital myasthenic syndrome), and the muscle (myopathies and muscular dystrophies). Historically, pediatric neuromuscular disorders have uniformly been considered to be without treatment possibilities and to have dire prognoses. This perception has gradually changed, starting in part with the discovery and widespread application of corticosteroids for Duchenne muscular dystrophy. At present, several exciting therapeutic avenues are under investigation for a range of conditions, offering the potential for significant improvements in patient morbidities and mortality and, in some cases, curative intervention. In this review, we will present the current state of treatment for the most common pediatric neuromuscular conditions, and detail the treatment strategies with the greatest potential for helping with these devastating diseases.
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Affiliation(s)
- James J. Dowling
- Division of NeurologyHospital for Sick ChildrenTorontoOntarioCanada
- Program for Genetics and Genome BiologyHospital for Sick ChildrenTorontoOntarioCanada
- Departments of Paediatrics and Molecular GeneticsUniversity of TorontoTorontoOntarioCanada
| | | | - Ronald D. Cohn
- Program for Genetics and Genome BiologyHospital for Sick ChildrenTorontoOntarioCanada
- Departments of Paediatrics and Molecular GeneticsUniversity of TorontoTorontoOntarioCanada
| | - Craig Campbell
- Department of PediatricsClinical Neurological SciencesEpidemiologyWestern UniversityLondonOntarioCanada
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Congenital myopathies: disorders of excitation-contraction coupling and muscle contraction. Nat Rev Neurol 2018; 14:151-167. [PMID: 29391587 DOI: 10.1038/nrneurol.2017.191] [Citation(s) in RCA: 178] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The congenital myopathies are a group of early-onset, non-dystrophic neuromuscular conditions with characteristic muscle biopsy findings, variable severity and a stable or slowly progressive course. Pronounced weakness in axial and proximal muscle groups is a common feature, and involvement of extraocular, cardiorespiratory and/or distal muscles can implicate specific genetic defects. Central core disease (CCD), multi-minicore disease (MmD), centronuclear myopathy (CNM) and nemaline myopathy were among the first congenital myopathies to be reported, and they still represent the main diagnostic categories. However, these entities seem to belong to a much wider phenotypic spectrum. To date, congenital myopathies have been attributed to mutations in over 20 genes, which encode proteins implicated in skeletal muscle Ca2+ homeostasis, excitation-contraction coupling, thin-thick filament assembly and interactions, and other mechanisms. RYR1 mutations are the most frequent genetic cause, and CCD and MmD are the most common subgroups. Next-generation sequencing has vastly improved mutation detection and has enabled the identification of novel genetic backgrounds. At present, management of congenital myopathies is largely supportive, although new therapeutic approaches are reaching the clinical trial stage.
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Abstract
PURPOSE OF REVIEW This article uses a case-based approach to highlight the clinical features as well as recent advances in molecular genetics, muscle imaging, and pathophysiology of the congenital myopathies. RECENT FINDINGS Congenital myopathies refer to a heterogeneous group of genetic neuromuscular disorders characterized by early-onset muscle weakness, hypotonia, and developmental delay. Congenital myopathies are further classified into core myopathies, centronuclear myopathies, nemaline myopathies, and congenital fiber-type disproportion based on the key pathologic features found in muscle biopsies. Genotype and phenotype correlations are hampered by the diverse clinical variability of the genes responsible for congenital myopathies, ranging from a severe neonatal course with early death to mildly affected adults with late-onset disease. An increasing number of genes have been identified, which, in turn, are associated with overlapping morphologic changes in the myofibers. Precise genetic diagnosis has important implications for disease management, including family counseling; avoidance of anesthetic-related muscle injury for at-risk individuals; monitoring for potential cardiac, respiratory, or orthopedic complications; as well as for participation in clinical trials or potential genetic therapies. SUMMARY Collaboration with neuromuscular experts, geneticists, neuroradiologists, neuropathologists, and other specialists is needed to ensure accurate and timely diagnosis based on clinical and pathologic features. An integrated multidisciplinary model of care based on expert-guided standards will improve quality of care and optimize outcomes for patients and families with congenital myopathies.
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MESH Headings
- Adult
- Child
- Child, Preschool
- Female
- Genetic Therapy/trends
- Humans
- Infant
- Infant, Newborn
- Male
- Mutation/genetics
- Myopathies, Nemaline/genetics
- Myopathies, Nemaline/pathology
- Myopathies, Nemaline/therapy
- Myopathies, Structural, Congenital/genetics
- Myopathies, Structural, Congenital/pathology
- Myopathies, Structural, Congenital/therapy
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Disturbed Ca 2+ Homeostasis in Muscle-Wasting Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1088:307-326. [PMID: 30390258 DOI: 10.1007/978-981-13-1435-3_14] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ca2+ is essential for proper structure and function of skeletal muscle. It not only activates contraction and force development but also participates in multiple signaling pathways. Low levels of Ca2+ restrain muscle regeneration by limiting the fusion of satellite cells. Ironically, sustained elevations of Ca2+ also result in muscle degeneration as this ion promotes high rates of protein breakdown. Moreover, transforming growth factors (TGFs) which are well known for controlling muscle growth also regulate Ca2+ channels. Thus, therapies focused on changing levels of Ca2+ and TGFs are promising for treating muscle-wasting disorders. Three principal systems govern the homeostasis of Ca2+, namely, excitation-contraction (EC) coupling, excitation-coupled Ca2+ entry (ECCE), and store-operated Ca2+ entry (SOCE). Accordingly, alterations in these systems can lead to weakness and atrophy in many hereditary diseases, such as Brody disease, central core disease (CCD), tubular aggregate myopathy (TAM), myotonic dystrophy type 1 (MD1), oculopharyngeal muscular dystrophy (OPMD), and Duchenne muscular dystrophy (DMD). Here, the interrelationship between all these molecules and processes is reviewed.
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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] [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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Khirani S, Dabaj I, Amaddeo A, Olmo Arroyo J, Ropers J, Tirolien S, Coudert V, Estournet B, Fauroux B, Quijano-Roy S. Effect of Salbutamol on Respiratory Muscle Strength in Spinal Muscular Atrophy. Pediatr Neurol 2017; 73:78-87.e1. [PMID: 28668232 DOI: 10.1016/j.pediatrneurol.2017.04.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/12/2017] [Indexed: 11/17/2022]
Abstract
BACKGROUND Oral salbutamol has shown clinical benefits in spinal muscular atrophy (SMA). We studied its effect on the respiratory muscle strength in children with different types of SMA. METHODS Lung and respiratory muscle functions were assessed in children receiving daily oral salbutamol for at least one year. The respiratory data of age-matched SMA II historical control subjects were compared with data of SMA II patients receiving salbutamol. RESULTS Seven children (6.4 ± 2.0 years old, range four to ten; one SMA I, five SMA II, and one SMA III) treated with salbutamol (duration 23 ± 8 months) were assessed. Maximal static inspiratory pressure, sniff nasal inspiratory pressure, and slow vital capacity were significantly better in the salbutamol-treated SMA II group compared with control subjects (P < 0.05). CONCLUSIONS Long-term oral salbutamol showed benefits in respiratory function in children with SMA and appeared to increase the strength of the inspiratory muscles in a small cohort of SMA II patients.
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Affiliation(s)
- Sonia Khirani
- ASV Santé, Gennevilliers, France; AP-HP, Hôpital Necker-Enfants Malades, Pediatric Noninvasive Ventilation and Sleep Unit, Paris, France
| | - Ivana Dabaj
- AP-HP, Hôpital Raymond Poincaré, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Pôle pédiatrique, Service de Pédiatrie, Garches, France; Centre de Référence Maladies Neuromusculaires Garches-Necker-Mondor-Hendaye (GNMH), Garches, France; Réseau National de Maladies Neuromusculaires FILNEMUS, Garches, France
| | - Alessandro Amaddeo
- AP-HP, Hôpital Necker-Enfants Malades, Pediatric Noninvasive Ventilation and Sleep Unit, Paris, France; INSERM U955, Créteil, France; Paris Descartes University, Paris, France
| | - Jorge Olmo Arroyo
- AP-HP, Hôpital Necker-Enfants Malades, Pediatric Noninvasive Ventilation and Sleep Unit, Paris, France
| | - Jacques Ropers
- Hôpitaux Universitaires Paris Île-de-France Ouest, Unité de Recherche Clinique, Boulogne, France
| | - Stéphane Tirolien
- AP-HP, Hôpital Raymond Poincaré, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Pôle pédiatrique, Service de Pédiatrie, Garches, France
| | - Véronique Coudert
- AP-HP, Hôpital Raymond Poincaré, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Pôle pédiatrique, Service de Pédiatrie, Garches, France
| | - Brigitte Estournet
- AP-HP, Hôpital Raymond Poincaré, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Pôle pédiatrique, Service de Pédiatrie, Garches, France; Centre de Référence Maladies Neuromusculaires Garches-Necker-Mondor-Hendaye (GNMH), Garches, France; Réseau National de Maladies Neuromusculaires FILNEMUS, Garches, France
| | - Brigitte Fauroux
- AP-HP, Hôpital Necker-Enfants Malades, Pediatric Noninvasive Ventilation and Sleep Unit, Paris, France; INSERM U955, Créteil, France; Paris Descartes University, Paris, France
| | - Susana Quijano-Roy
- AP-HP, Hôpital Raymond Poincaré, Hôpitaux Universitaires Paris-Ile-de-France Ouest, Pôle pédiatrique, Service de Pédiatrie, Garches, France; Centre de Référence Maladies Neuromusculaires Garches-Necker-Mondor-Hendaye (GNMH), Garches, France; Réseau National de Maladies Neuromusculaires FILNEMUS, Garches, France; INSERM U1179, Université Versailles Saint-Quentin (UVSQ), UFR des sciences de la santé Simone Veil, Montigny, France.
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Jungbluth H, Dowling JJ, Ferreiro A, Muntoni F, Bönnemann C, Dirksen R, Faure J, Hamilton S, Hopkins P, Marks A, Marty I, Meilleur K, Riazi S, Sewry C, Treves S, Voermans N, Zorzato F. 217th ENMC International Workshop: RYR1-related myopathies, Naarden, The Netherlands, 29–31 January 2016. Neuromuscul Disord 2016; 26:624-33. [DOI: 10.1016/j.nmd.2016.06.001] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 06/02/2016] [Indexed: 12/22/2022]
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Jungbluth H, Ochala J, Treves S, Gautel M. Current and future therapeutic approaches to the congenital myopathies. Semin Cell Dev Biol 2016; 64:191-200. [PMID: 27515125 DOI: 10.1016/j.semcdb.2016.08.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Revised: 08/04/2016] [Accepted: 08/08/2016] [Indexed: 12/14/2022]
Abstract
The congenital myopathies - including Central Core Disease (CCD), Multi-minicore Disease (MmD), Centronuclear Myopathy (CNM), Nemaline Myopathy (NM) and Congenital Fibre Type Disproportion (CFTD) - are a genetically heterogeneous group of early-onset neuromuscular conditions characterized by distinct histopathological features, and associated with a substantial individual and societal disease burden. Appropriate supportive management has substantially improved patient morbidity and mortality but there is currently no cure. Recent years have seen an exponential increase in the genetic and molecular understanding of these conditions, leading to the identification of underlying defects in proteins involved in calcium homeostasis and excitation-contraction coupling, thick/thin filament assembly and function, redox regulation, membrane trafficking and/or autophagic pathways. Based on these findings, specific therapies are currently being developed, or are already approaching the clinical trial stage. Despite undeniable progress, therapy development faces considerable challenges, considering the rarity and diversity of specific conditions, and the size and complexity of some of the genes and proteins involved. The present review will summarize the key genetic, histopathological and clinical features of specific congenital myopathies, and outline therapies already available or currently being developed in the context of known pathogenic mechanisms. The relevance of newly discovered molecular mechanisms and novel gene editing strategies for future therapy development will be discussed.
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Affiliation(s)
- Heinz Jungbluth
- Department of Paediatric Neurology, Neuromuscular Service, Evelina's Children Hospital, Guy's & St. Thomas' Hospital NHS Foundation Trust, London, United Kingdom; Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section Biophysics and Cardiovascular Division, King's College BHF Centre of Research Excellence, United Kingdom; Department of Basic and Clinical Neuroscience, IoPPN, King's College, London, United Kingdom.
| | - Julien Ochala
- Centre of Human and Aerospace Physiological Sciences, King's College London, United Kingdom
| | - Susan Treves
- Departments of Biomedicine and Anaesthesia, Basel University Hospital, 4031 Basel, Switzerland
| | - Mathias Gautel
- Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section Biophysics and Cardiovascular Division, King's College BHF Centre of Research Excellence, United Kingdom
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Bartus RT, Bétourné A, Basile A, Peterson BL, Glass J, Boulis NM. β2-Adrenoceptor agonists as novel, safe and potentially effective therapies for Amyotrophic lateral sclerosis (ALS). Neurobiol Dis 2015; 85:11-24. [PMID: 26459114 DOI: 10.1016/j.nbd.2015.10.006] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 09/25/2015] [Accepted: 10/08/2015] [Indexed: 02/04/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a chronic and progressive neuromuscular disease for which no cure exists and better treatment options are desperately needed. We hypothesize that currently approved β2-adrenoceptor agonists may effectively treat the symptoms and possibly slow the progression of ALS. Although β2-agonists are primarily used to treat asthma, pharmacologic data from animal models of neuromuscular diseases suggest that these agents may have pharmacologic effects of benefit in treating ALS. These include inhibiting protein degradation, stimulating protein synthesis, inducing neurotrophic factor synthesis and release, positively modulating microglial and systemic immune function, maintaining the structural and functional integrity of motor endplates, and improving energy metabolism. Moreover, stimulation of β2-adrenoceptors can activate a range of downstream signaling events in many different cell types that could account for the diverse array of effects of these agents. The evidence supporting the possible therapeutic benefits of β2-agonists is briefly reviewed, followed by a more detailed review of clinical trials testing the efficacy of β-agonists in a variety of human neuromuscular maladies. The weight of evidence of the potential benefits from treating these diseases supports the hypothesis that β2-agonists may be efficacious in ALS. Finally, ways to monitor and manage the side effects that may arise with chronic administration of β2-agonists are evaluated. In sum, effective, safe and orally-active β2-agonists may provide a novel and convenient means to reduce the symptoms of ALS and possibly delay disease progression, affording a unique opportunity to repurpose these approved drugs for treating ALS, and rapidly transforming the management of this serious, unmet medical need.
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Affiliation(s)
| | | | | | | | - Jonathan Glass
- Dept Neurology and Emory ALS Center, Emory University School of Medicine, Atlanta, GA, United States
| | - Nicholas M Boulis
- Dept Neurosurgery, Emory University School of Medicine, Atlanta, GA, United States
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21
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Abstract
The triad is a skeletal muscle substructure responsible for the regulation of excitation-contraction coupling. It is formed by the close apposition of the T-tubule and the terminal sarcoplasmic reticulum. A rapidly growing list of skeletal myopathies, here referred to as triadopathies, are caused by gene mutations in components of the triad. These disorders, at their root, are caused by defects in excitation contraction coupling and intracellular calcium homeostasis. Secondary abnormalities in triad structure and/or function are also reported in several muscle diseases, most notably certain muscular dystrophies. This review highlights the current understanding of both primary and secondary triadopathies, and identifies important concepts yet to be fully addressed in the field. The emphasis of the review is both on the pathogenesis of triadopathies and their potential treatment.
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Affiliation(s)
- James J Dowling
- Division of Neurology and Genetics and Genome Biology Program, Hospital for Sick Children, Toronto, ON, Canada,
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Obstetric outcome in a primigravid patient with autosomal-recessive multiminicore myopathy. Obstet Gynecol 2014; 123:438-440. [PMID: 24413229 DOI: 10.1097/aog.0000000000000003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND Multiminicore disease is a congenital myopathy characterized by muscle weakness and respiratory impairment. Predilection for the development of malignant hyperthermia has been reported in select patients. Little is known about pregnancy outcomes, although patients with other neuromuscular disorders may experience a postpartum decline. CASE We report a case of pregnancy associated with autosomal-recessive multiminicore disease. Genetic implications of this condition were addressed. Orthopedic complications were managed through physical medicine and rehabilitation consultation. Under epidural anesthesia, a healthy full-term neonate was delivered through spontaneous vaginal delivery. There was no evidence of malignant hyperthermia or functional decline in the puerperium. CONCLUSION A successful pregnancy outcome was achieved in a patient with multiminicore myopathy by proactively addressing potential genetic, orthopedic, and anesthetic concerns associated with this condition.
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Guerrero-Hernández A, Ávila G, Rueda A. Ryanodine receptors as leak channels. Eur J Pharmacol 2013; 739:26-38. [PMID: 24291096 DOI: 10.1016/j.ejphar.2013.11.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 11/21/2013] [Indexed: 01/18/2023]
Abstract
Ryanodine receptors are Ca(2+) release channels of internal stores. This review focuses on those situations and conditions that transform RyRs from a finely regulated ion channel to an unregulated Ca(2+) leak channel and the pathological consequences of this alteration. In skeletal muscle, mutations in either CaV1.1 channel or RyR1 results in a leaky behavior of the latter. In heart cells, RyR2 functions normally as a Ca(2+) leak channel during diastole within certain limits, the enhancement of this activity leads to arrhythmogenic situations that are tackled with different pharmacological strategies. In smooth muscle, RyRs are involved more in reducing excitability than in stimulating contraction so the leak activity of RyRs in the form of Ca(2+) sparks, locally activates Ca(2+)-dependent potassium channels to reduce excitability. In neurons the enhanced activity of RyRs is associated with the development of different neurodegenerative disorders such as Alzheimer and Huntington diseases. It appears then that the activity of RyRs as leak channels can have both physiological and pathological consequences depending on the cell type and the metabolic condition.
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Affiliation(s)
| | | | - Angélica Rueda
- Departamento de Bioquímica, Cinvestav, Mexico city, México
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Joassard OR, Durieux AC, Freyssenet DG. β2-Adrenergic agonists and the treatment of skeletal muscle wasting disorders. Int J Biochem Cell Biol 2013; 45:2309-21. [PMID: 23845739 DOI: 10.1016/j.biocel.2013.06.025] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 06/14/2013] [Accepted: 06/26/2013] [Indexed: 02/04/2023]
Abstract
β2-Agonists are traditionally used for the treatment of bronchospasm associated with asthma and the treatment of symptomatic patients with COPD. However, β2-agonists are also powerful anabolic agents that trigger skeletal muscle hypertrophy. Investigating the effects of β2-agonists in skeletal muscle over the past 30 years in different animal models has led to the identification of potential therapeutic applications in several muscle wasting disorders, including neuromuscular diseases, cancer cachexia, sepsis or thermal injury. In these conditions, numerous studies indicate that β2-agonists can attenuate and/or reverse the decrease in skeletal muscle mass and associated weakness in animal models of muscle wasting but also in human patients. The purpose of this review is to present the biological and clinical significance of β2-agonists for the treatment of skeletal muscle wasting. After the description of the molecular mechanisms involved in the hypertrophy and anti-atrophy effect of β2-agonists, we will review the anti-atrophy effects of β2-agonist administration in several animal models and human pathologies associated with or leading to skeletal muscle wasting. This article is part of a Directed Issue entitled: Molecular basis of muscle wasting.
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Affiliation(s)
- Olivier R Joassard
- Laboratoire de Physiologie de l'Exercice, Université de Lyon, F-42023 Saint-Etienne, France
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Next generation sequencing for molecular diagnosis of neuromuscular diseases. Acta Neuropathol 2012; 124:273-83. [PMID: 22526018 PMCID: PMC3400754 DOI: 10.1007/s00401-012-0982-8] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2012] [Revised: 04/05/2012] [Accepted: 04/05/2012] [Indexed: 12/21/2022]
Abstract
Inherited neuromuscular disorders (NMD) are chronic genetic diseases posing a significant burden on patients and the health care system. Despite tremendous research and clinical efforts, the molecular causes remain unknown for nearly half of the patients, due to genetic heterogeneity and conventional molecular diagnosis based on a gene-by-gene approach. We aimed to test next generation sequencing (NGS) as an efficient and cost-effective strategy to accelerate patient diagnosis. We designed a capture library to target the coding and splice site sequences of all known NMD genes and used NGS and DNA multiplexing to retrieve the pathogenic mutations in patients with heterogeneous NMD with or without known mutations. We retrieved all known mutations, including point mutations and small indels, intronic and exonic mutations, and a large deletion in a patient with Duchenne muscular dystrophy, validating the sensitivity and reproducibility of this strategy on a heterogeneous subset of NMD with different genetic inheritance. Most pathogenic mutations were ranked on top in our blind bioinformatic pipeline. Following the same strategy, we characterized probable TTN, RYR1 and COL6A3 mutations in several patients without previous molecular diagnosis. The cost was less than conventional testing for a single large gene. With appropriate adaptations, this strategy could be implemented into a routine genetic diagnosis set-up as a first screening approach to detect most kind of mutations, potentially before the need of more invasive and specific clinical investigations. An earlier genetic diagnosis should provide improved disease management and higher quality genetic counseling, and ease access to therapy or inclusion into therapeutic trials.
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Wadman RI, Bosboom WMJ, van der Pol WL, van den Berg LH, Wokke JHJ, Iannaccone ST, Vrancken AFJE. Drug treatment for spinal muscular atrophy types II and III. Cochrane Database Syst Rev 2012:CD006282. [PMID: 22513940 DOI: 10.1002/14651858.cd006282.pub4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by degeneration of anterior horn cells, which leads to progressive muscle weakness. Children with SMA type II do not develop the ability to walk without support and have a shortened life expectancy, whereas children with SMA type III develop the ability to walk and have a normal life expectancy. There are no known efficacious drug treatments that influence the disease course of SMA. This is an update of a review first published in 2009. OBJECTIVES To evaluate whether drug treatment is able to slow or arrest the disease progression of SMA types II and III and to assess if such therapy can be given safely. Drug treatment for SMA type I is the topic of a separate updated Cochrane review. SEARCH METHODS We searched the Cochrane Neuromuscular Disease Group Specialized Register (8 March 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), MEDLINE (January 1991 to February 2011), EMBASE (January 1991 to February 2011) and ISI Web of Knowledge (January 1991 to March 8 2011). We also searched clinicaltrials.gov to identify as yet unpublished trials (8 March 2011). SELECTION CRITERIA We sought all randomised or quasi-randomised trials that examined the efficacy of drug treatment for SMA types II and III. Participants had to fulfil the clinical criteria and have a deletion or mutation of the survival motor neuron 1 (SMN1) gene (5q11.2-13.2) that was confirmed by genetic analysis.The primary outcome measure was to be change in disability score within one year after the onset of treatment. Secondary outcome measures within one year after the onset of treatment were to be change in muscle strength, ability to stand or walk, change in quality of life, time from the start of treatment until death or full time ventilation and adverse events attributable to treatment during the trial period. DATA COLLECTION AND ANALYSIS Two authors independently reviewed and extracted data from all potentially relevant trials. Pooled relative risks and pooled standardised mean differences were to be calculated to assess treatment efficacy. Risk of bias was systematically analysed. MAIN RESULTS Six randomised placebo-controlled trials on treatment for SMA types II and III were found and included in the review: the four in the original review and two trials added in this update. The treatments were creatine (55 participants), phenylbutyrate (107 participants), gabapentin (84 participants), thyrotropin releasing hormone (9 participants), hydroxyurea (57 participants), and combination therapy with valproate and acetyl-L-carnitine (61 participants). None of these studies were completely free of bias. All studies had adequate blinding, sequence generation and reports of primary outcomes.None of the included trials showed any statistically significant effects on the outcome measures in participants with SMA types II and III. One participant died due to suffocation in the hydroxyurea trial and one participant died in the creatine trial. No participants in any of the other four trials died or reached the state of full time ventilation. Serious side effects were infrequent. AUTHORS' CONCLUSIONS There is no proven efficacious drug treatment for SMA types II and III.
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Affiliation(s)
- Renske I Wadman
- Department of Neurology, University Medical Center Utrecht, Utrecht, Netherlands.
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Wadman RI, Bosboom WM, van den Berg LH, Wokke JH, Iannaccone ST, Vrancken AF. Drug treatment for spinal muscular atrophy types II and III. Cochrane Database Syst Rev 2011:CD006282. [PMID: 22161400 DOI: 10.1002/14651858.cd006282.pub3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by degeneration of anterior horn cells, which leads to progressive muscle weakness. Children with SMA type II do not develop the ability to walk without support and have a shortened life expectancy, whereas children with SMA type III develop the ability to walk and have a normal life expectancy. There are no known efficacious drug treatments that influence the disease course of SMA. This is an update of a review first published in 2009. OBJECTIVES To evaluate whether drug treatment is able to slow or arrest the disease progression of SMA types II and III and to assess if such therapy can be given safely. Drug treatment for SMA type I is the topic of a separate updated Cochrane review. SEARCH METHODS We searched the Cochrane Neuromuscular Disease Group Specialized Register (8 March 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, Issue 1), MEDLINE (January 1991 to February 2011), EMBASE (January 1991 to February 2011) and ISI Web of Knowledge (January 1991 to March 8 2011). We also searched clinicaltrials.gov to identify as yet unpublished trials (8 March 2011). SELECTION CRITERIA We sought all randomised or quasi-randomised trials that examined the efficacy of drug treatment for SMA types II and III. Participants had to fulfil the clinical criteria and have a deletion or mutation of the survival motor neuron 1 (SMN1) gene (5q11.2-13.2) that was confirmed by genetic analysis.The primary outcome measure was to be change in disability score within one year after the onset of treatment. Secondary outcome measures within one year after the onset of treatment were to be change in muscle strength, ability to stand or walk, change in quality of life, time from the start of treatment until death or full time ventilation and adverse events attributable to treatment during the trial period. DATA COLLECTION AND ANALYSIS Two authors independently reviewed and extracted data from all potentially relevant trials. Pooled relative risks and pooled standardised mean differences were to be calculated to assess treatment efficacy. Risk of bias was systematically analysed. MAIN RESULTS Six randomised placebo-controlled trials on treatment for SMA types II and III were found and included in the review: the four in the original review and two trials added in this update. The treatments were creatine (55 participants), phenylbutyrate (107 participants), gabapentin (84 participants), thyrotropin releasing hormone (9 participants), hydroxyurea (57 participants), and combination therapy with valproate and acetyl-L-carnitine (61 participants). None of these studies were completely free of bias. All studies had adequate blinding, sequence generation and reports of primary outcomes.None of the included trials showed any statistically significant effects on the outcome measures in participants with SMA types II and III. One participant died due to suffocation in the hydroxyurea trial and one participant died in the creatine trial. No participants in any of the other four trials died or reached the state of full time ventilation. Serious side effects were infrequent. AUTHORS' CONCLUSIONS There is no proven efficacious drug treatment for SMA types II and III.
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Affiliation(s)
- Renske I Wadman
- Department of Neurology, University Medical Center Utrecht, Rudolf Magnus Institute for Neuroscience, Universiteitsweg 100, Utrecht, Netherlands, 3584 CG
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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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Lillis S, Abbs S, Mueller CR, Muntoni F, Jungbluth H. Clinical utility gene card for: Central core disease. Eur J Hum Genet 2011; 20:ejhg2011179. [PMID: 21989361 DOI: 10.1038/ejhg.2011.179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Suzanne Lillis
- GSTS Pathology, Guy's Hospital, Great Maze Pond, London, UK
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Vega AV, Ramos-Mondragón R, Calderón-Rivera A, Zarain-Herzberg A, Avila G. Calcitonin gene-related peptide restores disrupted excitation-contraction coupling in myotubes expressing central core disease mutations in RyR1. J Physiol 2011; 589:4649-69. [PMID: 21825032 DOI: 10.1113/jphysiol.2011.210765] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Central core disease (CCD) is a congenital human myopathy associated with mutations in the gene encoding the skeletal muscle ryanodine receptor (RyR1), resulting in skeletal muscle weakness and lower limb deformities. The muscle weakness can be at least partially explained by a reduced magnitude of voltage-gated Ca(2+) release (VGCR). To date, only a few studies have focused on identifying potential therapeutic agents for CCD. Therefore, in this work we investigated the potential use of the calcitonin gene related peptide (CGRP) to restore VGCR in myotubes expressing CCD RyR1 mutants. We also examined the influence of CCD mutants on Ca(2+)-dependent processes involved in myogenesis (myoblast fusion and sarcoendoplasmic reticulum Ca(2+)-ATPase isoform 2 (SERCA2) gene expression). C2C12 cells were transfected with cDNAs encoding either wild-type RyR1 or CCD mutants, and then exposed to CGRP (100 nm, 1-4 h). Expression of the I4897T mutant significantly inhibited SERCA2 gene expression and myoblast fusion, whereas the Y523S mutant exerted the opposite effect. Interestingly, both mutants clearly inhibited VGCR (50%), due to a reduction in SR Ca(2+) content. However, no major changes due to CGRP or CCD mutants were observed in I(CaL). Our data suggest that the Y523S mutant results in store depletion via decompensated SR Ca(2+) leak, while the I4897T mutant inhibits SERCA2 gene expression. Remarkably, in both cases CGRP restored VGCR, likely to have been by enhancing phospholamban (PLB) phosphorylation, SERCA activity and SR Ca(2+) content. Taken together, our data show that in the C2C12 model system, changes in excitation-contraction coupling induced by the expression of RyR1 channels bearing CCD mutations Y523S or I4897T can be reversed by CGRP.
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32
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Determination of Albuterol Enantiomers in Animal Tissue Matrices by LC–MS/MS: Application in Therapeutic Myoanabolic Studies. Chromatographia 2011. [DOI: 10.1007/s10337-011-2061-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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33
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Schreuder LTW, Nijhuis-van der Sanden MWG, de Hair A, Peters G, Wortmann S, Bok LA, Morava E. Successful use of albuterol in a patient with central core disease and mitochondrial dysfunction. J Inherit Metab Dis 2010; 33 Suppl 3:S205-9. [PMID: 20443062 PMCID: PMC3757256 DOI: 10.1007/s10545-010-9085-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 03/14/2010] [Accepted: 03/22/2010] [Indexed: 11/25/2022]
Abstract
Albuterol, a selective beta-adrenergic agonist, has been used experimentally in combination with exercise therapy in a few inherited neuromuscular disorders to increase muscle strength and muscle volume . We report on a 9-year-old boy with central core disease and mitochondrial dysfunction due to compound heterozygous RYR1 mutations receiving albuterol treatment for 1 year. Throughout the period of albuterol administration, the patient underwent an aerobic exercise regime of training sessions three times a week that lasted 20 min each. No side effects of albuterol use were seen. Significant clinical progress, including self care, sitting up, raising arms above the shoulders, independent feeding, and better speech and writing were observed compared with minimal development of these abilities in the previous years on physiotherapy. Improved forced expiratory volume in 1 s (FEV1) score was detected and increased muscle strength was noted: progress was measured using various functional tests and assessment scales. The only complication observed was a mild progression of the joint contractures, possibly due to an unbalance between the flexor and extensor musculature. In general, in this pilot study in a complex case of metabolic myopathy our patient has shown promising results following albuterol treatment and aerobic exercise therapy.
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Affiliation(s)
- L. T. W. Schreuder
- Departments of Pediatrics and Neurology, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, P.O Box 9101, 6500 HB Nijmegen, The Netherlands
| | | | - A. de Hair
- Pediatric Department, Máxima Medical Center Veldhoven, Veldhoven, The Netherlands
| | - G. Peters
- Department of Paediatric Physical Therapy, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands
| | - S. Wortmann
- Departments of Pediatrics and Neurology, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, P.O Box 9101, 6500 HB Nijmegen, The Netherlands
| | - L. A. Bok
- Pediatric Department, Máxima Medical Center Veldhoven, Veldhoven, The Netherlands
| | - E. Morava
- Departments of Pediatrics and Neurology, Nijmegen Centre for Mitochondrial Disorders, Radboud University Nijmegen Medical Centre, P.O Box 9101, 6500 HB Nijmegen, The Netherlands
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34
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Payan C, Hogrel J, Hammouda E, Lacomblez L, Ollivier G, Doppler V, Eymard B, Attarian S, Pouget J, Desnuelle C, Laforêt P. Periodic Salbutamol in Facioscapulohumeral Muscular Dystrophy: A Randomized Controlled Trial. Arch Phys Med Rehabil 2009; 90:1094-101. [DOI: 10.1016/j.apmr.2008.12.027] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2008] [Revised: 12/27/2008] [Accepted: 12/30/2008] [Indexed: 11/25/2022]
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35
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Bosboom WMJ, Vrancken AFJE, van den Berg LH, Wokke JHJ, Iannaccone ST. Drug treatment for spinal muscular atrophy types II and III. Cochrane Database Syst Rev 2009:CD006282. [PMID: 19160275 DOI: 10.1002/14651858.cd006282.pub2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by degeneration of anterior horn cells, which leads to progressive muscle weakness. Children with SMA type II do not develop the ability to walk without support and have a shortened life expectancy, whereas children with SMA type III develop the ability to walk and have a normal life expectancy. There are no known efficacious drug treatments that influence the disease course of SMA. OBJECTIVES To evaluate if drug treatment is able to slow or arrest the disease progression of SMA type II and III, and to assess if such therapy can be given safely. Drug treatment for SMA type I will be the topic of a separate Cochrane review. SEARCH STRATEGY We searched the Cochrane Neuromuscular Disease Group Trials Register (September 30 2008), The Cochrane Library (Issue 3, 2008), MEDLINE (January 1966 to June 2008), EMBASE (January 1980 to June 2008), ISI (January 1988 to June 2008), and ACP Journal Club (January 1991 to June 2008). SELECTION CRITERIA We sought all randomized or quasi-randomized trials that examined the efficacy of drug treatment for SMA type II and III. Participants had to fulfil the clinical criteria and, in studies including genetic analysis to confirm the diagnosis, have a deletion or mutation of the SMN1 gene (5q11.2-13.2)The primary outcome measure was to be change in disability score within one year after the onset of treatment. Secondary outcome measures within one year after the onset of treatment were to be change in muscle strength, ability to stand or walk, change in quality of life, time from the start of treatment until death or full time ventilation, and adverse events attributable to treatment during the trial period. DATA COLLECTION AND ANALYSIS Two authors independently reviewed and extracted data from all potentially relevant trials. Pooled relative risks and pooled weighted standardized mean differences were to be calculated to assess treatment efficacy MAIN RESULTS Four randomized placebo-controlled trials on treatment for SMA type II and III were found and included in the review. The treatments were creatine, phenylbutyrate, gabapentin and thyrotropin releasing hormone. None of these trials showed any effect on the outcome measures in patients with SMA type II and III. None of the patients in any of the four trials died or reached the state of full time ventilation and serious side effects were infrequent. AUTHORS' CONCLUSIONS There is no proven efficacious drug treatment for SMA type II and III.
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Affiliation(s)
- Wendy M J Bosboom
- Department of Neurology, Sint Lucas Andreas Hospital, Jan Tooropstraat 164, Amsterdam, Netherlands, 1061 AE.
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36
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Jungbluth H, Muntoni F, Ferreiro A. 150th ENMC International Workshop: Core Myopathies, 9–11th March 2007, Naarden, The Netherlands. Neuromuscul Disord 2008; 18:989-96. [DOI: 10.1016/j.nmd.2008.08.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Indexed: 11/16/2022]
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37
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Kinali M, Beeson D, Pitt M, Jungbluth H, Simonds A, Aloysius A, Cockerill H, Davis T, Palace J, Manzur A, Jimenez-Mallebrera C, Sewry C, Muntoni F, Robb S. Congenital Myasthenic Syndromes in childhood: Diagnostic and management challenges. J Neuroimmunol 2008; 201-202:6-12. [DOI: 10.1016/j.jneuroim.2008.06.026] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2008] [Revised: 06/07/2008] [Accepted: 06/09/2008] [Indexed: 10/21/2022]
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Pane M, Staccioli S, Messina S, D'Amico A, Pelliccioni M, Mazzone ES, Cuttini M, Alfieri P, Battini R, Main M, Muntoni F, Bertini E, Villanova M, Mercuri E. Daily salbutamol in young patients with SMA type II. Neuromuscul Disord 2008; 18:536-40. [PMID: 18579379 DOI: 10.1016/j.nmd.2008.05.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2008] [Revised: 05/05/2008] [Accepted: 05/12/2008] [Indexed: 11/15/2022]
Abstract
The aim of this open pilot study was to establish the profile of tolerability and clinical response of salbutamol (albuterol) in a cohort of young children affected by type II spinal muscular atrophy (SMA). Twenty-three children between 30 months and 6 years of age were treated with salbutamol (2 mg three times a day) for 1 year. All children were longitudinally assessed using the Hammersmith motor functional scale 6 months before treatment started (T0), at baseline (T1) and 6 and 12 months later. There was no significant change in function between T0 and T1 assessments, but the functional scores recorded after 6 and 12 months of treatment were significantly higher than those recorded at baseline (p=0.006). Our results suggest that salbutamol may be beneficial to SMA patients without producing any major side effect. Larger prospective randomized, double-blind, placebo controlled trials are needed to confirm these preliminary findings.
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Affiliation(s)
- Marika Pane
- Department of Paediatric Neurology, Catholic University, Policlinico Gemelli Largo Gemelli, 00168 Rome, Italy
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Mercuri E, Messina S, Pane M, Bertini E. Current methodological issues in the study of children with inherited neuromuscular disorders. Dev Med Child Neurol 2008; 50:417-21. [PMID: 18430158 DOI: 10.1111/j.1469-8749.2008.02066.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Several clinical trials assessing children with hereditary neuromuscular disorders have been performed over the last decade. These studies highlighted issues related to design and performance of clinical studies assessing children with this group of disorders. This article reviews recent literature and clinical experience in this area, highlighting methodological shortcomings and disease-specific clinical confounding factors that should be considered for future study design. The state of the art of outcome measures in neuromuscular disorders will be discussed, and suggestions for future clinical trials are presented.
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Affiliation(s)
- Eugenio Mercuri
- Department of Child Neurology, Catholic University, Policlinico Gemelli, Rome, Italy.
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40
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Abstract
This review focuses on congenital myopathies, a distinct but markedly heterogeneous group of muscle disorders that present with muscle weakness and typically appear at birth or in infancy. These myopathies have characteristic histopathologic abnormalities on muscle biopsy, allowing a preliminary morphologic classification. Advances in molecular genetics have allowed a more rational classification of these disorders and have reshuffled taxonomy for some of these conditions. Here, we focus on recent research advances in specific congenital myopathies, including nemaline myopathy, myotubular myopathy, centronuclear myopathy, central core myopathy, multi-minicore myopathy, congenital fiber-type disproportion myopathy, and hyaline body myopathy. Scientific progress has not only elucidated the pathologic mechanisms of these disorders, but it has also provided the basis for therapeutic strategies.
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Affiliation(s)
- Adele D'Amico
- Ospedale Bambino Gesù Research Chidren's Hospital, P.za S. Onofrio, 4, 00165 Rome, Italy
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41
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Abstract
Multi-minicore Disease (MmD) is a recessively inherited neuromuscular disorder characterized by multiple cores on muscle biopsy and clinical features of a congenital myopathy. Prevalence is unknown. Marked clinical variability corresponds to genetic heterogeneity: the most instantly recognizable classic phenotype characterized by spinal rigidity, early scoliosis and respiratory impairment is due to recessive mutations in the selenoprotein N (SEPN1) gene, whereas recessive mutations in the skeletal muscle ryanodine receptor (RYR1) gene have been associated with a wider range of clinical features comprising external ophthalmoplegia, distal weakness and wasting or predominant hip girdle involvement resembling central core disease (CCD). In the latter forms, there may also be a histopathologic continuum with CCD due to dominant RYR1 mutations, reflecting the common genetic background. Pathogenetic mechanisms of RYR1-related MmD are currently not well understood, but likely to involve altered excitability and/or changes in calcium homeoestasis; calcium-binding motifs within the selenoprotein N protein also suggest a possible role in calcium handling. The diagnosis of MmD is based on the presence of suggestive clinical features and multiple cores on muscle biopsy; muscle MRI may aid genetic testing as patterns of selective muscle involvement are distinct depending on the genetic background. Mutational analysis of the RYR1 or the SEPN1 gene may provide genetic confirmation of the diagnosis. Management is mainly supportive and has to address the risk of marked respiratory impairment in SEPN1-related MmD and the possibility of malignant hyperthermia susceptibility in RYR1-related forms. In the majority of patients, weakness is static or only slowly progressive, with the degree of respiratory impairment being the most important prognostic factor.
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Affiliation(s)
- Heinz Jungbluth
- Department of Paediatric Neurology, Evelina Children's Hospital, St. Thomas' Hospital, London, UK.
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42
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Abstract
Central core disease (CCD) is an inherited neuromuscular disorder characterised by central cores on muscle biopsy and clinical features of a congenital myopathy. Prevalence is unknown but the condition is probably more common than other congenital myopathies. CCD typically presents in infancy with hypotonia and motor developmental delay and is characterized by predominantly proximal weakness pronounced in the hip girdle; orthopaedic complications are common and malignant hyperthermia susceptibility (MHS) is a frequent complication. CCD and MHS are allelic conditions both due to (predominantly dominant) mutations in the skeletal muscle ryanodine receptor (RYR1) gene, encoding the principal skeletal muscle sarcoplasmic reticulum calcium release channel (RyR1). Altered excitability and/or changes in calcium homeostasis within muscle cells due to mutation-induced conformational changes of the RyR protein are considered the main pathogenetic mechanism(s). The diagnosis of CCD is based on the presence of suggestive clinical features and central cores on muscle biopsy; muscle MRI may show a characteristic pattern of selective muscle involvement and aid the diagnosis in cases with equivocal histopathological findings. Mutational analysis of the RYR1 gene may provide genetic confirmation of the diagnosis. Management is mainly supportive and has to anticipate susceptibility to potentially life-threatening reactions to general anaesthesia. Further evaluation of the underlying molecular mechanisms may provide the basis for future rational pharmacological treatment. In the majority of patients, weakness is static or only slowly progressive, with a favourable long-term outcome.
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Affiliation(s)
- Heinz Jungbluth
- Evelina Children's Hospital, Department of Paediatric Neurology, St. Thomas' Hospital, London, UK.
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