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Smeets N, Gheldof A, Dequeker B, Poleur M, Maldonado Slootjes S, Van Parijs V, Deconinck N, Dontaine P, Alonso-Jimenez A, De Bleecker J, De Ridder W, Herdewyn S, Paquay S, Vanlander A, De Waele L, Peirens G, Beysen D, Claeys KG, Dubuisson N, Hansen I, Remiche G, Seneca S, Bissay V, Régal L. Congenital Myasthenic Syndromes in Belgium: Genetic and Clinical Characterization of Pediatric and Adult Patients. Pediatr Neurol 2024; 158:57-65. [PMID: 38964204 DOI: 10.1016/j.pediatrneurol.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 05/29/2024] [Accepted: 06/05/2024] [Indexed: 07/06/2024]
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) are a group of genetic disorders characterized by impaired neuromuscular transmission. CMS typically present at a young age with fatigable muscle weakness, often with an abnormal response after repetitive nerve stimulation (RNS). Pharmacologic treatment can improve symptoms, depending on the underlying defect. Prevalence is likely underestimated. This study reports on patients with CMS followed in Belgium in 2022. METHODS Data were gathered retrospectively from the medical charts. Only likely pathogenic and pathogenic variants were included in the analysis. RESULTS We identified 37 patients, resulting in an estimated prevalence of 3.19 per 1,000,000. The patients harbored pathogenic variants in CHRNE, RAPSN, DOK7, PREPL, CHRNB1, CHRNG, COLQ, MUSK, CHRND, GFPT1, and GMPPB. CHRNE was the most commonly affected gene. Most patients showed disease onset at birth, during infancy, or during childhood. Symptom onset was at adult age in seven patients, caused by variants in CHRNE, DOK7, MUSK, CHRND, and GMPPB. Severity and distribution of weakness varied, as did the presence of respiratory involvement, feeding problems, and extraneuromuscular manifestations. RNS was performed in 23 patients of whom 18 demonstrated a pathologic decrement. Most treatment responses were predictable based on the genotype. CONCLUSIONS This is the first pooled characterization of patients with CMS in Belgium. We broaden the phenotypical spectrum of pathogenic variants in CHRNE with adult-onset CMS. Systematically documenting larger cohorts of patients with CMS can aid in better clinical characterization and earlier recognition of this rare disease. We emphasize the importance of establishing a molecular genetic diagnosis to tailor treatment choices.
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Affiliation(s)
- Nathalie Smeets
- Child Neurology Unit, Department of Pediatrics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium.
| | - Alexander Gheldof
- Center of Medical Genetics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Bart Dequeker
- Center of Medical Genetics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Margaux Poleur
- University Department of Neurology, Citadelle Hospital of Liège, Liège, Belgium
| | | | - Vinciane Van Parijs
- Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Nicolas Deconinck
- Department of Pediatric Neurology, Queen Fabiola Children's University Hospital, Université Libre De Bruxelles, Brussels, Belgium
| | - Pauline Dontaine
- Department of Pediatric Neurology, Queen Fabiola Children's University Hospital, Université Libre De Bruxelles, Brussels, Belgium
| | - Alicia Alonso-Jimenez
- Department of Neurology, University of Antwerp, Antwerp University Hospital, Antwerp, Belgium
| | - Jan De Bleecker
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - Willem De Ridder
- Department of Neurology, University of Antwerp, Antwerp University Hospital, Antwerp, Belgium
| | - Sarah Herdewyn
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - Stéphanie Paquay
- Department of Neuropediatrics, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Arnaud Vanlander
- Department of Pediatric Neurology and Metabolic Diseases, Ghent University Hospital, Ghent, Belgium
| | - Liesbeth De Waele
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium; Department of Pediatric Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Geertrui Peirens
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium; Department of Pediatric Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Diane Beysen
- Department of Pediatric Neurology, University of Antwerp, Antwerp University Hospital, Antwerp, Belgium
| | - Kristl G Claeys
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium; Laboratory for Muscle Diseases and Neuropathies, Department of Neurosciences, KU Leuven, Leuven Brain Institute (LBI), Leuven, Belgium
| | - Nicolas Dubuisson
- Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Isabelle Hansen
- Department of Neurology, University of Liège, Centre Hospitalier Universitaire de Liège, Liège, Belgium
| | - Gauthier Remiche
- Department of Neurology, Hôpital Universitaire de Bruxelles - Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Sara Seneca
- Center of Medical Genetics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Véronique Bissay
- NEUR Research Group and Department of Neurology, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Luc Régal
- Child Neurology Unit, Department of Pediatrics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
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Ziaadini B, Ghaderi Yazdi B, Dirandeh E, Boostani R, Karimi N, Panahi A, Kariminejad A, Fadaee M, Ahangari F, Nafissi S. DOK7 congenital myasthenic syndrome: case series and review of literature. BMC Neurol 2024; 24:211. [PMID: 38907197 PMCID: PMC11191154 DOI: 10.1186/s12883-024-03713-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 06/05/2024] [Indexed: 06/23/2024] Open
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) are among the most challenging differential diagnoses in the neuromuscular domain, consisting of diverse genotypes and phenotypes. A mutation in the Docking Protein 7 (Dok-7) is a common cause of CMS. DOK7 CMS requires different treatment than other CMS types. Regarding DOK7's special considerations and challenges ahead of neurologists, we describe seven DOK7 patients and evaluate their response to treatment. METHODS The authors visited these patients in the neuromuscular clinics of Tehran and Kerman Universities of Medical Sciences Hospitals. They diagnosed these patients based on clinical findings and neurophysiological studies, which Whole Exome Sequencing confirmed. For each patient, we tried unique medications and recorded the clinical response. RESULTS The symptoms started from birth to as late as the age of 33, with the mean age of onset being 12.5. Common symptoms were: Limb-girdle weakness in 6, fluctuating symptoms in 5, ptosis in 4, bifacial weakness in 3, reduced extraocular movement in 3, bulbar symptoms in 2 and dyspnea in 2 3-Hz RNS was decremental in 5 out of 6 patients. Salbutamol was the most effective. c.1124_1127dupTGCC is the most common variant; three patients had this variant. CONCLUSION We strongly recommend that neurologists consider CMS in patients with these symptoms and a similar familial history. We recommend prescribing salbutamol as the first-choice treatment option for DOK7 patients.
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Affiliation(s)
- Bentolhoda Ziaadini
- Neurology Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Bardyia Ghaderi Yazdi
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Shariati Hospital, North Karegar St, Tehran, 14117-13135, Iran
- Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Elham Dirandeh
- Clinical Research Development Unit, Kowsar Educational, Research and Therapeutic Hospital, Semnan University of Medical Sciences, Semnan, Iran
| | - Reza Boostani
- Department of Neurology, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Narges Karimi
- Department of Neurology, School of Medicine, Immunogenetics Research Center, Toxoplasmosis Research Center, Clinical Research Development Unit of Bou Ali Sina Hospital, Mazandaran University of Medical Sciences, Sari, Iran
| | - Akram Panahi
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Shariati Hospital, North Karegar St, Tehran, 14117-13135, Iran
- Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Mahsa Fadaee
- Kariminejad-Najmabadi Pathology & Genetics Center, Tehran, Iran
| | | | - Shahriar Nafissi
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Shariati Hospital, North Karegar St, Tehran, 14117-13135, Iran.
- Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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Batheja A, Bayer-Vile J, Silverstein E, Couser N. Congenital Myasthenic Syndrome associated with acetylcholine receptor deficiency: case report and review of the literature. Ophthalmic Genet 2024:1-7. [PMID: 38832364 DOI: 10.1080/13816810.2024.2352391] [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: 12/21/2023] [Accepted: 05/02/2024] [Indexed: 06/05/2024]
Abstract
INTRODUCTION Congenital Myasthenic Syndromes are a diverse group of conditions with a broad array of genetic underpinnings and phenotypic presentations. Acetylcholine receptor deficiency is one form that usually involves pathogenic variants in the Cholinergic Receptor Nicotinic Epsilon Subunit (CHRNE) gene encoding the ɛ-subunit of the acetylcholine receptor. METHODS We report a case of a 4-year-old male with suspected Congenital Myasthenic Syndrome with Acetylcholine Receptor Deficiency who presented with ocular symptoms and generalized muscle weakness. We additionally summarize published findings regarding the genetic, phenotypic, and clinical considerations of Congenital Myasthenic Syndrome with Acetylcholine Receptor Deficiency. RESULTS Exome sequencing revealed biallelic variants in CHRNE gene with a pathogenic frameshift variant and a variant of uncertain significance. After suboptimal response to pyridostigmine and albuterol, the patient experienced benefit with 3,4-DAP. The most commonly reported clinical characteristics in the literature are ptosis, muscle fatigability or weakness, and ophthalmoplegia. CONCLUSION We present the case of a patient with biallelic variants in CHRNE gene including a variant of uncertain significance. Evaluation of variants of this gene, including the variant of uncertain significance identified in this case report, through further cases and studies may improve our understanding of Congenital Myasthenic Syndrome with Acetylcholine Receptor deficiency.
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Affiliation(s)
- Aashish Batheja
- School of Medicine, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Julie Bayer-Vile
- Department of Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Evan Silverstein
- Department of Ophthalmology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
| | - Natario Couser
- Department of Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
- Department of Ophthalmology, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
- Department of Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA
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4
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Banerjee A, Datta Kanjilal S, Biswas T, Ghoshal A, Sarkar S. Congenital myasthenic syndrome: a tale of two siblings. Int J Neurosci 2024; 134:253-255. [PMID: 36018836 DOI: 10.1080/00207454.2022.2100774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 06/29/2022] [Accepted: 06/30/2022] [Indexed: 10/15/2022]
Abstract
Congenital myasthenic syndromes are a group of rare neuromuscular junction disorders. Traditional anticholinesterase inhibitors may not help in congenital myasthenic syndromes and in some variants may actually cause deterioration of symptoms. In this report, we describe a rare case of congenital myasthenic syndrome with heterozygous mutations in CHRNE gene (c.128A > T; heterozygous; exon 11) and COLQ gene (c.1201T > A; heterozygous; exon 16), which did not show improvement on neostigmine test but responded to treatment with oral salbutamol.
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Affiliation(s)
- Ahitagni Banerjee
- Department of Pediatrics, Institute of Post Graduate Medical Education and Research, Kolkata, India
| | - Sumana Datta Kanjilal
- Department of Pediatrics, Institute of Post Graduate Medical Education and Research, Kolkata, India
| | - Tamoghna Biswas
- Department of Pediatrics, Institute of Post Graduate Medical Education and Research, Kolkata, India
| | - Arnab Ghoshal
- Department of Pediatrics, Institute of Post Graduate Medical Education and Research, Kolkata, India
| | - Sumit Sarkar
- Department of Pediatrics, Institute of Post Graduate Medical Education and Research, Kolkata, India
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5
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Kediha MI, Tazir M, Sternberg D, Eymard B, Ali Pacha L. Innovative Therapeutic Approaches in Congenital Myasthenic Syndromes. Neurol Clin Pract 2024; 14:e200277. [PMID: 38737513 PMCID: PMC11081764 DOI: 10.1212/cpj.0000000000200277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 01/10/2024] [Indexed: 05/14/2024]
Abstract
Background and Objectives To provide real-word clinical follow-up data on patients carrying variations of congenital myasthenic syndromes (CMS) and who respond to some innovative drugs. Methods Patients recruited from the Neurology Department of the Mustapha Bacha university hospital in Algiers. Treated with innovative drugs, they were monitored and their clinical progress was evaluated on the basis of clinical arguments suggestive of CMSs, but also para clinical arguments (electromyography and genetic study). Results Six patients carrying different mutations in different genes of CMSs were studied. They had different pathophysiologic profiles (slow or fast channel syndromes, low expressor of receptor). Their therapeutic management was based on innovative drugs, normally indicated in other, non-neurological pathologies. Their outcome was toward a clear clinical improvement. Discussion This work relates the interest of proposing treatments (outside of Pyridostigmine) in the management of CMSs. These therapies can greatly modify the prognosis of patients suffering from this orphan disease. Classification of Evidence This study provides Class IV evidence that for patients with congenital myasthenic syndromes, some innovative treatments are effective.
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Affiliation(s)
- Mohamed I Kediha
- Neurology Department (MIK, MT, LAP), Mustapha Bacha University Hospital Algiers, Algeria; Myology Department (DS), Pitié Salpetriere, Paris; and Functional Unit for Neuromuscular Pathology (BE), Pitié Salpetriere, France
| | - Meriem Tazir
- Neurology Department (MIK, MT, LAP), Mustapha Bacha University Hospital Algiers, Algeria; Myology Department (DS), Pitié Salpetriere, Paris; and Functional Unit for Neuromuscular Pathology (BE), Pitié Salpetriere, France
| | - Damien Sternberg
- Neurology Department (MIK, MT, LAP), Mustapha Bacha University Hospital Algiers, Algeria; Myology Department (DS), Pitié Salpetriere, Paris; and Functional Unit for Neuromuscular Pathology (BE), Pitié Salpetriere, France
| | - Bruno Eymard
- Neurology Department (MIK, MT, LAP), Mustapha Bacha University Hospital Algiers, Algeria; Myology Department (DS), Pitié Salpetriere, Paris; and Functional Unit for Neuromuscular Pathology (BE), Pitié Salpetriere, France
| | - Lamia Ali Pacha
- Neurology Department (MIK, MT, LAP), Mustapha Bacha University Hospital Algiers, Algeria; Myology Department (DS), Pitié Salpetriere, Paris; and Functional Unit for Neuromuscular Pathology (BE), Pitié Salpetriere, France
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6
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Benarroch E. What Is the Role of the Sympathetic System in Skeletal Muscle? Neurology 2024; 102:e209488. [PMID: 38710007 DOI: 10.1212/wnl.0000000000209488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/08/2024] Open
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7
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Zambon AA, Falzone YM, Bolino A, Previtali SC. Molecular mechanisms and therapeutic strategies for neuromuscular diseases. Cell Mol Life Sci 2024; 81:198. [PMID: 38678519 PMCID: PMC11056344 DOI: 10.1007/s00018-024-05229-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 03/14/2024] [Accepted: 04/07/2024] [Indexed: 05/01/2024]
Abstract
Neuromuscular diseases encompass a heterogeneous array of disorders characterized by varying onset ages, clinical presentations, severity, and progression. While these conditions can stem from acquired or inherited causes, this review specifically focuses on disorders arising from genetic abnormalities, excluding metabolic conditions. The pathogenic defect may primarily affect the anterior horn cells, the axonal or myelin component of peripheral nerves, the neuromuscular junction, or skeletal and/or cardiac muscles. While inherited neuromuscular disorders have been historically deemed not treatable, the advent of gene-based and molecular therapies is reshaping the treatment landscape for this group of condition. With the caveat that many products still fail to translate the positive results obtained in pre-clinical models to humans, both the technological development (e.g., implementation of tissue-specific vectors) as well as advances on the knowledge of pathogenetic mechanisms form a collective foundation for potentially curative approaches to these debilitating conditions. This review delineates the current panorama of therapies targeting the most prevalent forms of inherited neuromuscular diseases, emphasizing approved treatments and those already undergoing human testing, offering insights into the state-of-the-art interventions.
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Affiliation(s)
- Alberto Andrea Zambon
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Yuri Matteo Falzone
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Bolino
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Stefano Carlo Previtali
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy.
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy.
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8
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Núñez-Carpintero I, Rigau M, Bosio M, O'Connor E, Spendiff S, Azuma Y, Topf A, Thompson R, 't Hoen PAC, Chamova T, Tournev I, Guergueltcheva V, Laurie S, Beltran S, Capella-Gutiérrez S, Cirillo D, Lochmüller H, Valencia A. Rare disease research workflow using multilayer networks elucidates the molecular determinants of severity in Congenital Myasthenic Syndromes. Nat Commun 2024; 15:1227. [PMID: 38418480 PMCID: PMC10902324 DOI: 10.1038/s41467-024-45099-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 01/15/2024] [Indexed: 03/01/2024] Open
Abstract
Exploring the molecular basis of disease severity in rare disease scenarios is a challenging task provided the limitations on data availability. Causative genes have been described for Congenital Myasthenic Syndromes (CMS), a group of diverse minority neuromuscular junction (NMJ) disorders; yet a molecular explanation for the phenotypic severity differences remains unclear. Here, we present a workflow to explore the functional relationships between CMS causal genes and altered genes from each patient, based on multilayer network community detection analysis of complementary biomedical information provided by relevant data sources, namely protein-protein interactions, pathways and metabolomics. Our results show that CMS severity can be ascribed to the personalized impairment of extracellular matrix components and postsynaptic modulators of acetylcholine receptor (AChR) clustering. This work showcases how coupling multilayer network analysis with personalized -omics information provides molecular explanations to the varying severity of rare diseases; paving the way for sorting out similar cases in other rare diseases.
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Affiliation(s)
- Iker Núñez-Carpintero
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
| | - Maria Rigau
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK
- Institute of Clinical Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, Du Cane Road, London, W12 0NN, UK
| | - Mattia Bosio
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Coordination Unit Spanish National Bioinformatics Institute (INB/ELIXIR-ES), Barcelona Supercomputing Center, Barcelona, Spain
| | - Emily O'Connor
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Yoshiteru Azuma
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
- Department of Pediatrics, Aichi Medical University, Nagakute, Japan
| | - Ana Topf
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, Newcastle University, Newcastle upon Tyne, United Kingdom
- Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, United Kingdom
| | - Rachel Thompson
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Peter A C 't Hoen
- Center for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud university medical center, Nijmegen, The Netherlands
| | - Teodora Chamova
- Department of Neurology, Expert Centre for Hereditary Neurologic and Metabolic Disorders, Alexandrovska University Hospital, Medical University-Sofia, Sofia, Bulgaria
| | - Ivailo Tournev
- Department of Neurology, Expert Centre for Hereditary Neurologic and Metabolic Disorders, Alexandrovska University Hospital, Medical University-Sofia, Sofia, Bulgaria
- Department of Cognitive Science and Psychology, New Bulgarian University, Sofia, 1618, Bulgaria
| | - Velina Guergueltcheva
- Clinic of Neurology, University Hospital Sofiamed, Sofia University St. Kliment Ohridski, Sofia, Bulgaria
| | - Steven Laurie
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
| | - Sergi Beltran
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain
- Universitat Pompeu Fabra (UPF), Barcelona, Spain
- Departament de Genètica, Microbiologia i Estadística, Facultat de Biologia, Universitat de Barcelona (UB), Barcelona, Spain
| | - Salvador Capella-Gutiérrez
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Coordination Unit Spanish National Bioinformatics Institute (INB/ELIXIR-ES), Barcelona Supercomputing Center, Barcelona, Spain
| | - Davide Cirillo
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain.
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
- 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, ON, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Alfonso Valencia
- Barcelona Supercomputing Center (BSC), Plaça Eusebi Güell, 1-3, 08034, Barcelona, Spain
- Coordination Unit Spanish National Bioinformatics Institute (INB/ELIXIR-ES), Barcelona Supercomputing Center, Barcelona, Spain
- ICREA, Pg. Lluís Companys 23, 08010, Barcelona, Spain
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Chen X, Qiu J, Gao Z, Liu B, Zhang C, Yu W, Yang J, Shen Y, Qi L, Yao X, Sun H, Yang X. Myasthenia gravis: Molecular mechanisms and promising therapeutic strategies. Biochem Pharmacol 2023; 218:115872. [PMID: 37865142 DOI: 10.1016/j.bcp.2023.115872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 10/23/2023]
Abstract
Myasthenia gravis (MG) is a type of autoimmune disease caused by the blockage of neuromuscular junction transmission owing to the attack of autoantibodies on transmission-related proteins. Related antibodies, such as anti-AChR, anti-MuSK and anti-LRP4 antibodies, can be detected in most patients with MG. Although traditional therapies can control most symptoms, several challenges remain to be addressed, necessitating the development of more effective and safe treatment strategies for MG. With the in-depth exploration on the mechanism and immune targets of MG, effective therapies, especially therapies using biologicals, have been reported recently. Given the important roles of immune cells, cytokines and intercellular interactions in the pathological process of MG, B-cell targeted therapy, T-cell targeted therapy, proteasome inhibitors targeting plasma cell, complement inhibitors, FcRn inhibitors have been developed for the treatment of MG. Although these novel therapies exert good therapeutic effects, they may weaken the immunity and increase the risk of infection in MG patients. This review elaborates on the pathogenesis of MG and discusses the advantages and disadvantages of the strategies of traditional treatment and biologicals. In addition, this review emphasises that combined therapy may have better therapeutic effects and reducing the risk of side effects of treatments, which has great prospects for the treatment of MG. With the deepening of research on immunotherapy targets in MG, novel opportunities and challenges in the treatment of MG will be introduced.
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Affiliation(s)
- Xin Chen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Jiayi Qiu
- Department of Clinical Medicine, Medical College, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Zihui Gao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Boya Liu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Chen Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Weiran Yu
- Department of Clinical Medicine, Medical College, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Jiawen Yang
- Department of Clinical Medicine, Medical College, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Yuntian Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Lei Qi
- Department of Emergency Medicine, Affiliated Hospital of Nantong University, Nantong, Jiangsu Province 226001, PR China
| | - Xinlei Yao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China.
| | - Hualin Sun
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China.
| | - Xiaoming Yang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, Co-Innovation Center of Neuroregeneration, Department of Neurology, Affiliated Hospital of Nantong University, Nantong University, Nantong, Jiangsu Province 226001, PR China.
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10
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Qaisar R. Targeting neuromuscular junction to treat neuromuscular disorders. Life Sci 2023; 333:122186. [PMID: 37858716 DOI: 10.1016/j.lfs.2023.122186] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 10/21/2023]
Abstract
The integrity and preservation of the neuromuscular junction (NMJ), the interface between the motor neuron and skeletal muscle, is critical for maintaining a healthy skeletal muscle. The structural and/or functional defects in the three cellular components of NMJ, namely the pre-synaptic terminal, synaptic cleft, and post-synaptic region, negatively affect skeletal muscle mass and/or strength. Therefore, NMJ repair appears to be an appropriate therapy for muscle disorders. Mouse models provide a detailed molecular characterization of various cellular components of NMJ with relevance to human diseases. This review discusses different molecular targets on the three cellular components of NMJ for treating muscle diseases. The potential effects of these therapies on NMJ morphology and motor performance, their therapeutic efficacy, and clinical relevance are discussed. Collectively, the available data supports targeting NMJ alone or as an adjunct therapy in treating muscle disorders. However, the potential impact of such interventions on human patients with muscle disorders requires further investigation.
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Affiliation(s)
- Rizwan Qaisar
- Basic Medical Sciences, College of Medicine, University of Sharjah, Sharjah, United Arab Emirates; Space Medicine Research Group, Sharjah Institute for Medical and Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates; Cardiovascular Research Group, Sharjah Institute for Medical and Health Sciences, University of Sharjah, Sharjah 27272, United Arab Emirates.
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11
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Bricoune O, Hamner B, Gieron-Korthals M. Challenges in Diagnosing and Treating Myasthenia Gravis in Infants and Children with Presentation of Cases. Adv Pediatr 2023; 70:81-90. [PMID: 37422299 DOI: 10.1016/j.yapd.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/10/2023]
Abstract
Myasthenia gravis (MG) is a rare condition that impairs function at the neuromuscular junction of skeletal muscles, seen less commonly in children. Causes include autoimmune MG, congenital myasthenic syndromes, and transient neonatal myasthenia gravis. Symptoms of weakness, hypotonia, and fatigability can be reasonably explained by more common causes, thus children with MG disorders commonly experience delays in treatment with severe consequences. This leads to the progression of disease and serious complications including myasthenic crises and exacerbations. We describe 5 cases of MG, which illustrate clinical and genetic challenges in establishing diagnosis and subsequent consequences of delayed diagnosis.
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Affiliation(s)
- Ornella Bricoune
- Department of Neurology, University of South Florida Morsani College of Medicine, Tampa, FL, USA; University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Boulevard, Tampa, FL 33612, USA
| | - Bailey Hamner
- University of South Florida Morsani College of Medicine, 12901 Bruce B. Downs Boulevard, Tampa, FL 33612, USA
| | - Maria Gieron-Korthals
- Pediatric Neurology, University of South Florida Morsani College of Medicine, Tampa, FL, USA.
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12
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Rodríguez Cruz PM, Ravenscroft G, Natera D, Carr A, Manzur A, Liu WW, Vella NR, Jericó I, Gonzalez-Quereda L, Gallano P, Montalto SA, Davis MR, Lamont PJ, Laing NG, Bourque P, Nascimento A, Muntoni F, Polavarapu K, Lochmüller H, Palace J, Beeson D. A novel phenotype of AChR-deficiency syndrome with predominant facial and distal weakness resulting from the inclusion of an evolutionary alternatively-spliced exon in CHRNA1. Neuromuscul Disord 2023; 33:161-168. [PMID: 36634413 DOI: 10.1016/j.nmd.2022.12.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022]
Abstract
Primary acetylcholine receptor deficiency is the most common subtype of congenital myasthenic syndrome, resulting in reduced amount of acetylcholine receptors expressed at the muscle endplate and impaired neuromuscular transmission. AChR deficiency is caused mainly by pathogenic variants in the ε-subunit of the acetylcholine receptor encoded by CHRNE, although pathogenic variants in other subunits are also seen. We report the clinical and molecular features of 13 patients from nine unrelated kinships with acetylcholine receptor deficiency harbouring the CHRNA1 variant NM_001039523.3:c.257G>A (p.Arg86His) in homozygosity or compound heterozygosity. This variant results in the inclusion of an alternatively-spliced evolutionary exon (P3A) that causes expression of a non-functional acetylcholine receptor α-subunit. We compare the clinical findings of this group to the other cases of acetylcholine receptor deficiency within our cohort. We report differences in phenotype, highlighting a predominant pattern of facial and distal weakness in adulthood, predominantly in the upper limbs, which is unusual for acetylcholine receptor deficiency syndromes, and more in keeping with slow-channel syndrome or distal myopathy. Finally, we stress the importance of including alternative exons in variant analysis to increase the probability of achieving a molecular diagnosis.
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Affiliation(s)
- Pedro M Rodríguez Cruz
- CNAG-CRG, Centro Nacional de Análisis Genómico - Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Gianina Ravenscroft
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia; Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia
| | - Daniel Natera
- Neuromuscular Unit, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Aisling Carr
- Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK
| | - Adnan Manzur
- Dubowitz Neuromuscular Centre, NIHR Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health; Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Wei Wei Liu
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, UK
| | - Norbert R Vella
- Department of Neuroscience, Mater Dei Hospital, Msida, Malta
| | - Ivonne Jericó
- Department of Neurology, Hospital Universitario de Navarra, IdisNa (Instituto Investigación Sanitaria Navarra), Pamplona, Spain
| | - Lidia Gonzalez-Quereda
- Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain; Department of Genetics, Hospital de Sant Pau, IIB Sant Pau, Barcelona, Spain
| | - Pia Gallano
- Center for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain; Department of Genetics, Hospital de Sant Pau, IIB Sant Pau, Barcelona, Spain
| | | | - Mark R Davis
- Neurogenetic Unit, Department of Diagnostic Genomics, PathWest Laboratory Medicine, Western Australian Department of Health, Nedlands, WA, Australia
| | - Phillipa J Lamont
- Department of Neurology, Royal Perth Hospital, Nedlands, WA, Australia
| | - Nigel G Laing
- Harry Perkins Institute of Medical Research, Nedlands, WA, Australia; Centre of Medical Research, University of Western Australia, Nedlands, WA, Australia; Neurogenetic Unit, Department of Diagnostic Genomics, PathWest Laboratory Medicine, Western Australian Department of Health, Nedlands, WA, Australia
| | - Pierre Bourque
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | | | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, NIHR Biomedical Research Centre, UCL Great Ormond Street Institute of Child Health; Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Kiran Polavarapu
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada
| | - Hanns Lochmüller
- CNAG-CRG, Centro Nacional de Análisis Genómico - Centre for Genomic Regulation, Barcelona Institute of Science and Technology, Barcelona, Spain; Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada; Division of Neurology, Department of Medicine, The Ottawa Hospital; and Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada; Department of Neuropediatrics and Muscle Disorders, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany.
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, UK; Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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13
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Krenn M, Sener M, Rath J, Zulehner G, Keritam O, Wagner M, Laccone F, Iglseder S, Marte S, Baumgartner M, Eisenkölbl A, Liechtenstein C, Rudnik S, Quasthoff S, Grinzinger S, Spenger J, Wortmann SB, Löscher WN, Zimprich F, Kellersmann A, Rappold M, Bernert G, Freilinger M, Cetin H. The clinical and molecular landscape of congenital myasthenic syndromes in Austria: a nationwide study. J Neurol 2023; 270:909-916. [PMID: 36308527 PMCID: PMC9886627 DOI: 10.1007/s00415-022-11440-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 02/03/2023]
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) are a heterogeneous group of disorders caused by genetic defects resulting in impaired neuromuscular transmission. Although effective treatments are available, CMS is probably underdiagnosed, and systematic clinico-genetic investigations are warranted. METHODS We used a nationwide approach to collect Austrian patients with genetically confirmed CMS. We provide a clinical and molecular characterization of this cohort and aimed to ascertain the current frequency of CMS in Austria. RESULTS Twenty-eight cases with genetically confirmed CMS were identified, corresponding to an overall prevalence of 3.1 per million (95% CI 2.0-4.3) in Austria. The most frequent genetic etiology was CHRNE (n = 13), accounting for 46.4% of the cohort. Within this subgroup, the variant c.1327del, p.(Glu443Lysfs*64) was detected in nine individuals. Moreover, causative variants were found in DOK7 (n = 4), RAPSN (n = 3), COLQ (n = 2), GMPPB (n = 2), CHAT (n = 1), COL13A1 (n = 1), MUSK (n = 1) and AGRN (n = 1). Clinical onset within the first year of life was reported in one half of the patients. Across all subtypes, the most common symptoms were ptosis (85.7%), lower limb (67.9%), upper limb (60.7%) and facial weakness (60.7%). The majority of patients (96.4%) received specific treatment, including acetylcholinesterase inhibitors in 20, adrenergic agonists in 11 and 3,4-diaminopyridine in nine patients. CONCLUSIONS Our study presents the first systematic characterization of individuals with CMS in Austria, providing prevalence estimates and genotype-phenotype correlations that may help to improve the diagnostic approach and patient management.
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Affiliation(s)
- Martin Krenn
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Merve Sener
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Jakob Rath
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Gudrun Zulehner
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Omar Keritam
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Matias Wagner
- Institute of Human Genetics, Technical University of Munich, Munich, Germany.,Institute for Neurogenomics, Helmholtz Center Munich, Munich, Germany
| | - Franco Laccone
- Institute of Medical Genetics, Medical University of Vienna, Vienna, Austria
| | - Stephan Iglseder
- Department of Neurology, Krankenhaus Barmherzige Brüder, Linz, Austria
| | | | - Manuela Baumgartner
- Department of Neuropaediatrics, Hospital Barmherzige Schwestern Linz, Linz, Austria
| | - Astrid Eisenkölbl
- Department of Paediatrics and Adolescent Medicine, Johannes Kepler University Linz, Linz, Austria
| | - Christian Liechtenstein
- Department of Paediatrics and Adolescent Medicine, Villach Regional Hospital, Villach, Austria
| | - Sabine Rudnik
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefan Quasthoff
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Susanne Grinzinger
- Department of Neurology, Salzburger Landeskliniken, Paracelsus Medical University, Salzburg, Austria
| | - Johannes Spenger
- University Children's Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Saskia B Wortmann
- University Children's Hospital, Paracelsus Medical University, Salzburg, Austria.,Amalia Children's Hospital, Radboudumc, Nijmegen, The Netherlands
| | - Wolfgang N Löscher
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Fritz Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | | | - Mika Rappold
- Department of Pediatrics, Klinik Favoriten, Vienna, Austria
| | | | - Michael Freilinger
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Hakan Cetin
- Department of Neurology, Medical University of Vienna, Vienna, Austria.
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14
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Heidarpour N, Singh A, Caputo JM, Barbieri R, Pampana VS, Kamath VG, Kaur G. Unfolding of Novel Independent Missense Mutations in VAMP2 and AGRN and Their Collective Role in Global Developmental Delay: A Case Report. Cureus 2022; 14:e28464. [PMID: 36176870 PMCID: PMC9511814 DOI: 10.7759/cureus.28464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2022] [Indexed: 11/08/2022] Open
Abstract
Vesicle-associated membrane protein 2 (VAMP2) and Agrin (AGRN) are crucial proteins in neurotransmission. VAMP2 is a vesicular protein that facilitates the exocytosis of neurotransmitters. At the same time, AGRN plays a critical role in the maintenance and function of neuromuscular junctions. Mutations in the signaling pathway of VAMP2 and AGRN impair proper signaling between the presynaptic and postsynaptic neurons, and can result in neurodevelopmental conditions known as global developmental delay (GDD). This study highlights a presentation of GDD in a patient with concurrent mutations in VAMP2 and AGRN. A three-year-old female child presented with GDD characterized by hypotonia, intellectual disability, and dysphagia. Physical exam exhibited signs of developmental delay and severe muscle weakness. EEG findings were suggestive of a hypsarrhythmia pattern. The ophthalmological evaluation showed partial optic atrophy bilaterally. Therapeutic interventions included Keppra and Topamax, which proved ineffective. The patient’s outcome was inconclusive as care was transferred to another facility. This case study reports the novel appearance of two concurrent mutations: p.Gln76Pro associated with VAMP2 and p.Gln970Glu associated with AGRN. Mutations in VAMP2 lead to a dysfunctional SNARE complex and inhibit exocytosis of neurotransmitters into the synaptic cleft. Mutations in AGRN impair the ability to form and activate postsynaptic nicotinic acetylcholine receptors. Improper signaling between presynaptic and postsynaptic neurons is an important determinant of GDD. We hope that accounting for this mutational pattern will contribute to understanding synapse assembly and help unravel the complex interplay of factors involved in the pathology of neuromuscular disorders and GDD.
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15
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Davis RL, Kumar KR, Puttick C, Liang C, Ahmad KE, Edema-Hildebrand F, Park JS, Minoche AE, Gayevskiy V, Mallawaarachchi AC, Christodoulou J, Schofield D, Dinger ME, Cowley MJ, Sue CM. Use of Whole-Genome Sequencing for Mitochondrial Disease Diagnosis. Neurology 2022; 99:e730-e742. [PMID: 35641312 PMCID: PMC9484606 DOI: 10.1212/wnl.0000000000200745] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 04/04/2022] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Mitochondrial diseases (MDs) are the commonest group of heritable metabolic disorders. Phenotypic diversity can make molecular diagnosis challenging, and causative genetic variants may reside in either mitochondrial or nuclear DNA. A single comprehensive genetic diagnostic test would be highly useful and transform the field. We applied whole-genome sequencing (WGS) to evaluate the variant detection rate and diagnostic capacity of this technology with a view to simplifying and improving the MD diagnostic pathway. METHODS Adult patients presenting to a specialist MD clinic in Sydney, Australia, were recruited to the study if they satisfied clinical MD (Nijmegen) criteria. WGS was performed on blood DNA, followed by clinical genetic analysis for known pathogenic MD-associated variants and MD mimics. RESULTS Of the 242 consecutive patients recruited, 62 participants had "definite," 108 had "probable," and 72 had "possible" MD classification by the Nijmegen criteria. Disease-causing variants were identified for 130 participants, regardless of the location of the causative genetic variants, giving an overall diagnostic rate of 53.7% (130 of 242). Identification of causative genetic variants informed precise treatment, restored reproductive confidence, and optimized clinical management of MD. DISCUSSION Comprehensive bigenomic sequencing accurately detects causative genetic variants in affected MD patients, simplifying diagnosis, enabling early treatment, and informing the risk of genetic transmission.
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16
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Garg D, Goyal V. Positive response to inhaled salbutamol in congenital myasthenic syndrome due to CHRNE mutation. Muscle Nerve 2022; 66:E1-E2. [PMID: 35466404 DOI: 10.1002/mus.27563] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/17/2022] [Accepted: 04/19/2022] [Indexed: 11/06/2022]
Affiliation(s)
- Divyani Garg
- Department of Neurosciences, Neo Hospital, Noida, India
| | - Vinay Goyal
- Neurosciences Institute, Medanta The Medicity, Gurgaon, India
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17
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Dutta A, Chakraborty A, Das S, Dubey S, Pandit A. Salbutamol monotherapy in acetylcholine receptor deficiency-related congenital myasthenic syndrome due to CHRNE mutation. J Neurol 2022; 269:3923-3925. [PMID: 35175423 DOI: 10.1007/s00415-022-11018-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 02/06/2022] [Accepted: 02/08/2022] [Indexed: 11/29/2022]
Affiliation(s)
- Arpan Dutta
- Department of Neurology, Bangur Institute of Neurosciences, 22/7/1, Pranabananda Road, Garia, Kolkata, 700084, India.
| | - Arkaprava Chakraborty
- Department of Neurology, Bangur Institute of Neurosciences, 22/7/1, Pranabananda Road, Garia, Kolkata, 700084, India
| | - Shambaditya Das
- Department of Neurology, Bangur Institute of Neurosciences, 22/7/1, Pranabananda Road, Garia, Kolkata, 700084, India
| | - Souvik Dubey
- Department of Neurology, Bangur Institute of Neurosciences, 22/7/1, Pranabananda Road, Garia, Kolkata, 700084, India
| | - Alak Pandit
- Department of Neurology, Bangur Institute of Neurosciences, 22/7/1, Pranabananda Road, Garia, Kolkata, 700084, India
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18
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Pallithanam JJ, Prabhudesai SP, Naik N, Gauns S. COLQ-Related Congenital Myasthenic Syndrome in a Child from Western India. Neurol India 2021; 69:228-229. [PMID: 33642313 DOI: 10.4103/0028-3886.310105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
| | | | - Neeta Naik
- Department of Pediatrics, Healthway Hospital, Mapusa, Goa, India
| | - Shivanand Gauns
- Department of Pediatrics, Gauns Child Care Hospital, Mapusa, Goa, India
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19
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Fernandes M, Caetano A, Pinto M, Medeiros E, Santos L. Diagnosis of DOK7 congenital myasthenic syndrome during pregnancy: A case report and literature review. Clin Neurol Neurosurg 2021; 203:106591. [PMID: 33714798 DOI: 10.1016/j.clineuro.2021.106591] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/14/2021] [Accepted: 02/27/2021] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Pregnancy among patients with congenital myasthenic syndrome (CMS) is a rare occurrence. Since most of the patients with CMS reach adulthood, questions regarding clinical outcome with pregnancy arise. CASE REPORT We describe a 38-year-old Portuguese female who presented in the second trimester of pregnancy with proximal fluctuating limb-girdle weakness, hyperlordosis, waddling gait, dysphagia, dysphonia and ptosis, with no ophthalmoparesis. Initial diagnosis of seronegative myasthenia, supported by neurophysiology findings, led to unsuccessful treatment with intravenous immunoglobulin, pyridostigmine, prednisolone and plasmapheresis, and the patient slowly progressed to a severe tetraparesis with facial and bulbar involvement. Genetic testing for CMS identified a novel compound heterozygous mutation (c.1124_1127dupTGCC and c.935_936del) in the DOK7 gene. Subsequent treatment with salbutamol resulted in substantial clinical benefit. CONCLUSIONS This case underlines the importance of considering the diagnosis of CMS in patients with fluctuating weakness during pregnancy. Patients of child-bearing potential diagnosed with CMS, particularly due to DOK7 mutations, should be counseled in advance and closely followed during pregnancy.
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Affiliation(s)
- Marco Fernandes
- Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Rua da Junqueira 126, 1349-019, Lisbon, Portugal.
| | - André Caetano
- Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Rua da Junqueira 126, 1349-019, Lisbon, Portugal; CEDOC Chronic Diseases Research Centre, Nova Medical School / Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Miguel Pinto
- Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Rua da Junqueira 126, 1349-019, Lisbon, Portugal
| | - Elmira Medeiros
- Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Rua da Junqueira 126, 1349-019, Lisbon, Portugal; CEDOC Chronic Diseases Research Centre, Nova Medical School / Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Luís Santos
- Department of Neurology, Hospital de Egas Moniz, Centro Hospitalar de Lisboa Ocidental, Rua da Junqueira 126, 1349-019, Lisbon, Portugal; CEDOC Chronic Diseases Research Centre, Nova Medical School / Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
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20
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Kudryavtsev D, Isaeva A, Barkova D, Spirova E, Mukhutdinova R, Kasheverov I, Tsetlin V. Point Mutations of Nicotinic Receptor α1 Subunit Reveal New Molecular Features of G153S Slow-Channel Myasthenia. Molecules 2021; 26:molecules26051278. [PMID: 33652901 PMCID: PMC7956382 DOI: 10.3390/molecules26051278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/18/2021] [Accepted: 02/23/2021] [Indexed: 11/16/2022] Open
Abstract
Slow-channel congenital myasthenic syndromes (SCCMSs) are rare genetic diseases caused by mutations in muscle nicotinic acetylcholine receptor (nAChR) subunits. Most of the known SCCMS-associated mutations localize at the transmembrane region near the ion pore. Only two SCCMS point mutations are at the extracellular domains near the acetylcholine binding site, α1(G153S) being one of them. In this work, a combination of molecular dynamics, targeted mutagenesis, fluorescent Ca2+ imaging and patch-clamp electrophysiology has been applied to G153S mutant muscle nAChR to investigate the role of hydrogen bonds formed by Ser 153 with C-loop residues near the acetylcholine-binding site. Introduction of L199T mutation to the C-loop in the vicinity of Ser 153 changed hydrogen bonds distribution, decreased acetylcholine potency (EC50 2607 vs. 146 nM) of the double mutant and decay kinetics of acetylcholine-evoked cytoplasmic Ca2+ rise (τ 14.2 ± 0.3 vs. 34.0 ± 0.4 s). These results shed light on molecular mechanisms of nAChR activation-desensitization and on the involvement of such mechanisms in channelopathy genesis.
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Affiliation(s)
- Denis Kudryavtsev
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.I.); (E.S.); (R.M.); (I.K.); (V.T.)
- Correspondence:
| | - Anastasia Isaeva
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.I.); (E.S.); (R.M.); (I.K.); (V.T.)
- Moscow Institute of Physics and Technology, 141700 Dolgoprudny, Russia
| | - Daria Barkova
- Biological Department, Lomonosov Moscow State University, 119991 Moscow, Russia;
| | - Ekaterina Spirova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.I.); (E.S.); (R.M.); (I.K.); (V.T.)
| | - Renata Mukhutdinova
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.I.); (E.S.); (R.M.); (I.K.); (V.T.)
- Biological Department, Lomonosov Moscow State University, 119991 Moscow, Russia;
| | - Igor Kasheverov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.I.); (E.S.); (R.M.); (I.K.); (V.T.)
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Trubetskaya str. 8, bld. 2, 119991 Moscow, Russia
| | - Victor Tsetlin
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Miklukho-Maklaya 16/10, 117997 Moscow, Russia; (A.I.); (E.S.); (R.M.); (I.K.); (V.T.)
- Institute of Engineering Physics for Biomedicine, MePhi, 115409 Moscow, Russia
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21
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Cetin H, Beeson D, Vincent A, Webster R. The Structure, Function, and Physiology of the Fetal and Adult Acetylcholine Receptor in Muscle. Front Mol Neurosci 2020; 13:581097. [PMID: 33013323 PMCID: PMC7506097 DOI: 10.3389/fnmol.2020.581097] [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: 07/07/2020] [Accepted: 08/13/2020] [Indexed: 12/31/2022] Open
Abstract
The neuromuscular junction (NMJ) is a highly developed synapse linking motor neuron activity with muscle contraction. A complex of molecular cascades together with the specialized NMJ architecture ensures that each action potential arriving at the motor nerve terminal is translated into an action potential in the muscle fiber. The muscle-type nicotinic acetylcholine receptor (AChR) is a key molecular component located at the postsynaptic muscle membrane responsible for the generation of the endplate potential (EPP), which usually exceeds the threshold potential necessary to activate voltage-gated sodium channels and triggers a muscle action potential. Two AChR isoforms are found in mammalian muscle. The fetal isoform is present in prenatal stages and is involved in the development of the neuromuscular system whereas the adult isoform prevails thereafter, except after denervation when the fetal form is re-expressed throughout the muscle. This review will summarize the structural and functional differences between the two isoforms and outline congenital and autoimmune myasthenic syndromes that involve the isoform specific AChR subunits.
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Affiliation(s)
- Hakan Cetin
- Department of Neurology, Medical University of Vienna, Vienna, Austria.,Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Richard Webster
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
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Takamori M. Myasthenia Gravis: From the Viewpoint of Pathogenicity Focusing on Acetylcholine Receptor Clustering, Trans-Synaptic Homeostasis and Synaptic Stability. Front Mol Neurosci 2020; 13:86. [PMID: 32547365 PMCID: PMC7272578 DOI: 10.3389/fnmol.2020.00086] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
Myasthenia gravis (MG) is a disease of the postsynaptic neuromuscular junction (NMJ) where nicotinic acetylcholine (ACh) receptors (AChRs) are targeted by autoantibodies. Search for other pathogenic antigens has detected the antibodies against muscle-specific tyrosine kinase (MuSK) and low-density lipoprotein-related protein 4 (Lrp4), both causing pre- and post-synaptic impairments. Agrin is also suspected as a fourth pathogen. In a complex NMJ organization centering on MuSK: (1) the Wnt non-canonical pathway through the Wnt-Lrp4-MuSK cysteine-rich domain (CRD)-Dishevelled (Dvl, scaffold protein) signaling acts to form AChR prepatterning with axonal guidance; (2) the neural agrin-Lrp4-MuSK (Ig1/2 domains) signaling acts to form rapsyn-anchored AChR clusters at the innervated stage of muscle; (3) adaptor protein Dok-7 acts on MuSK activation for AChR clustering from “inside” and also on cytoskeleton to stabilize AChR clusters by the downstream effector Sorbs1/2; (4) the trans-synaptic retrograde signaling contributes to the presynaptic organization via: (i) Wnt-MuSK CRD-Dvl-β catenin-Slit 2 pathway; (ii) Lrp4; and (iii) laminins. The presynaptic Ca2+ homeostasis conditioning ACh release is modified by autoreceptors such as M1-type muscarinic AChR and A2A adenosine receptors. The post-synaptic structure is stabilized by: (i) laminin-network including the muscle-derived agrin; (ii) the extracellular matrix proteins (including collagen Q/perlecan and biglycan which link to MuSK Ig1 domain and CRD); and (iii) the dystrophin-associated glycoprotein complex. The study on MuSK ectodomains (Ig1/2 domains and CRD) recognized by antibodies suggested that the MuSK antibodies were pathologically heterogeneous due to their binding to multiple functional domains. Focussing one of the matrix proteins, biglycan which functions in the manner similar to collagen Q, our antibody assay showed the negative result in MG patients. However, the synaptic stability may be impaired by antibodies against MuSK ectodomains because of the linkage of biglycan with MuSK Ig1 domain and CRD. The pathogenic diversity of MG is discussed based on NMJ signaling molecules.
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Vanhaesebrouck AE, Webster R, Maxwell S, Rodriguez Cruz PM, Cossins J, Wickens J, Liu WW, Cetin H, Cheung J, Ramjattan H, Palace J, Beeson D. β2-Adrenergic receptor agonists ameliorate the adverse effect of long-term pyridostigmine on neuromuscular junction structure. Brain 2020; 142:3713-3727. [PMID: 31633155 PMCID: PMC6892641 DOI: 10.1093/brain/awz322] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/04/2019] [Accepted: 08/26/2019] [Indexed: 01/07/2023] Open
Abstract
Acetylcholine receptor deficiency is the most common form of the congenital myasthenic syndromes, a heterogeneous collection of genetic disorders of neuromuscular transmission characterized by fatiguable muscle weakness. Most patients with acetylcholine receptor deficiency respond well to acetylcholinesterase inhibitors; however, in some cases the efficacy of acetylcholinesterase inhibitors diminishes over time. Patients with acetylcholine receptor deficiency can also benefit from the addition of a β2-adrenergic receptor agonist to their medication. The working mechanism of β2-adrenergic agonists in myasthenic patients is not fully understood. Here, we report the long-term follow-up for the addition of β2-adrenergic agonists for a cohort of patients with acetylcholine receptor deficiency on anticholinesterase medication that demonstrates a sustained quantitative improvement. Coincidently we used a disease model to mirror the treatment of acetylcholine receptor deficiency, and demonstrate improved muscle fatigue, improved neuromuscular transmission and improved synaptic structure resulting from the addition of the β2-adrenergic agonist salbutamol to the anticholinesterase medication pyridostigmine. Following an initial improvement in muscle fatiguability, a gradual decline in the effect of pyridostigmine was observed in mice treated with pyridostigmine alone (P < 0.001). Combination therapy with pyridostigmine and salbutamol counteracted this decline (P < 0.001). Studies of compound muscle action potential decrement at high nerve stimulation frequencies (P < 0.05) and miniature end-plate potential amplitude analysis (P < 0.01) showed an improvement in mice following combination therapy, compared to pyridostigmine monotherapy. Pyridostigmine alone reduced postsynaptic areas (P < 0.001) and postsynaptic folding (P < 0.01). Combination therapy increased postsynaptic area (P < 0.001) and promoted the formation of postsynaptic junctional folds (P < 0.001), in particular in fast-twitch muscles. In conclusion, we demonstrate for the first time how the improvement seen in patients from adding salbutamol to their medication can be explained in an experimental model of acetylcholine receptor deficiency, the most common form of congenital myasthenic syndrome. Salbutamol enhances neuromuscular junction synaptic structure by counteracting the detrimental effects of long-term acetylcholinesterase inhibitors on the postsynaptic neuromuscular junction. The results have implications for both autoimmune and genetic myasthenias where anticholinesterase medication is a standard treatment.
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Affiliation(s)
- An E Vanhaesebrouck
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Richard Webster
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Susan Maxwell
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Pedro M Rodriguez Cruz
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK.,Department of Clinical Neurology, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Judith Cossins
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - James Wickens
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Wei-Wei Liu
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Hakan Cetin
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Jonathan Cheung
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Hayley Ramjattan
- Paediatric Neurology, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Jacqueline Palace
- Department of Clinical Neurology, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
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Tannemaat MR, Verschuuren JJ. Emerging therapies for autoimmune myasthenia gravis: Towards treatment without corticosteroids. Neuromuscul Disord 2020; 30:111-119. [DOI: 10.1016/j.nmd.2019.12.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 12/09/2019] [Accepted: 12/11/2019] [Indexed: 12/22/2022]
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Wadman RI, van der Pol WL, Bosboom WMJ, Asselman F, van den Berg LH, Iannaccone ST, Vrancken AFJE. Drug treatment for spinal muscular atrophy types II and III. Cochrane Database Syst Rev 2020; 1:CD006282. [PMID: 32006461 PMCID: PMC6995983 DOI: 10.1002/14651858.cd006282.pub5] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Spinal muscular atrophy (SMA) is caused by a homozygous deletion of the survival motor neuron 1 (SMN1) gene on chromosome 5, or a heterozygous deletion in combination with a (point) mutation in the second SMN1 allele. This results in 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. This is an update of a review first published in 2009 and previously updated in 2011. OBJECTIVES To evaluate if 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. SEARCH METHODS We searched the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, and ISI Web of Science conference proceedings in October 2018. In October 2018, we also searched two trials registries to identify unpublished trials. 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 homozygous deletion or hemizygous deletion in combination with a point mutation in the second allele of the SMN1 gene (5q11.2-13.2) confirmed by genetic analysis. The primary outcome measure was change in disability score within one year after the onset of treatment. Secondary outcome measures within one year after the onset of treatment were 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. Treatment strategies involving SMN1-replacement with viral vectors are out of the scope of this review, but a summary is given in Appendix 1. Drug treatment for SMA type I is the topic of a separate Cochrane Review. DATA COLLECTION AND ANALYSIS We followed standard Cochrane methodology. MAIN RESULTS The review authors found 10 randomised, placebo-controlled trials of treatments for SMA types II and III for inclusion in this review, with 717 participants. We added four of the trials at this update. The trials investigated creatine (55 participants), gabapentin (84 participants), hydroxyurea (57 participants), nusinersen (126 participants), olesoxime (165 participants), phenylbutyrate (107 participants), somatotropin (20 participants), thyrotropin-releasing hormone (TRH) (nine participants), valproic acid (33 participants), and combination therapy with valproic acid and acetyl-L-carnitine (ALC) (61 participants). Treatment duration was from three to 24 months. None of the studies investigated the same treatment and none was completely free of bias. All studies had adequate blinding, sequence generation and reporting of primary outcomes. Based on moderate-certainty evidence, intrathecal nusinersen improved motor function (disability) in children with SMA type II, with a 3.7-point improvement in the nusinersen group on the Hammersmith Functional Motor Scale Expanded (HFMSE; range of possible scores 0 to 66), compared to a 1.9-point decline on the HFMSE in the sham procedure group (P < 0.01; n = 126). On all motor function scales used, higher scores indicate better function. Based on moderate-certainty evidence from two studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: creatine (median change 1 higher, 95% confidence interval (CI) -1 to 2; on the Gross Motor Function Measure (GMFM), scale 0 to 264; n = 40); and combination therapy with valproic acid and carnitine (mean difference (MD) 0.64, 95% CI -1.1 to 2.38; on the Modified Hammersmith Functional Motor Scale (MHFMS), scale 0 to 40; n = 61). Based on low-certainty evidence from other single studies, the following interventions had no clinically important effect on motor function scores in SMA types II or III (or both) in comparison to placebo: gabapentin (median change 0 in the gabapentin group and -2 in the placebo group on the SMA Functional Rating Scale (SMAFRS), scale 0 to 50; n = 66); hydroxyurea (MD -1.88, 95% CI -3.89 to 0.13 on the GMFM, scale 0 to 264; n = 57), phenylbutyrate (MD -0.13, 95% CI -0.84 to 0.58 on the Hammersmith Functional Motor Scale (HFMS) scale 0 to 40; n = 90) and monotherapy of valproic acid (MD 0.06, 95% CI -1.32 to 1.44 on SMAFRS, scale 0 to 50; n = 31). Very low-certainty evidence suggested that the following interventions had little or no effect on motor function: olesoxime (MD 2, 95% -0.25 to 4.25 on the Motor Function Measure (MFM) D1 + D2, scale 0 to 75; n = 160) and somatotropin (median change at 3 months 0.25 higher, 95% CI -1 to 2.5 on the HFMSE, scale 0 to 66; n = 19). One small TRH trial did not report effects on motor function and the certainty of evidence for other outcomes from this trial were low or very low. Results of nine completed trials investigating 4-aminopyridine, acetyl-L-carnitine, CK-2127107, hydroxyurea, pyridostigmine, riluzole, RO6885247/RG7800, salbutamol and valproic acid were awaited and not available for analysis at the time of writing. Various trials and studies investigating treatment strategies other than nusinersen (e.g. SMN2-augmentation by small molecules), are currently ongoing. AUTHORS' CONCLUSIONS Nusinersen improves motor function in SMA type II, based on moderate-certainty evidence. Creatine, gabapentin, hydroxyurea, phenylbutyrate, valproic acid and the combination of valproic acid and ALC probably have no clinically important effect on motor function in SMA types II or III (or both) based on low-certainty evidence, and olesoxime and somatropin may also have little to no clinically important effect but evidence was of very low-certainty. One trial of TRH did not measure motor function.
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Affiliation(s)
- Renske I Wadman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - W Ludo van der Pol
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Wendy MJ Bosboom
- Onze Lieve Vrouwe Gasthuis locatie WestDepartment of NeurologyAmsterdamNetherlands
| | - Fay‐Lynn Asselman
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Leonard H van den Berg
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
| | - Susan T Iannaccone
- University of Texas Southwestern Medical CenterDepartment of Pediatrics5323 Harry Hines BoulevardDallasTexasUSA75390
| | - Alexander FJE Vrancken
- University Medical Center Utrecht, Brain Center Rudolf MagnusDepartment of NeurologyHeidelberglaan 100UtrechtNetherlands3584 CX
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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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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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Targeted therapies for congenital myasthenic syndromes: systematic review and steps towards a treatabolome. Emerg Top Life Sci 2019; 3:19-37. [PMID: 30931400 PMCID: PMC6436731 DOI: 10.1042/etls20180100] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite recent scientific advances, most rare genetic diseases — including most neuromuscular diseases — do not currently have curative gene-based therapies available. However, in some cases, such as vitamin, cofactor or enzyme deficiencies, channelopathies and disorders of the neuromuscular junction, a confirmed genetic diagnosis provides guidance on treatment, with drugs available that may significantly alter the disease course, improve functional ability and extend life expectancy. Nevertheless, many treatable patients remain undiagnosed or do not receive treatment even after genetic diagnosis. The growth of computer-aided genetic analysis systems that enable clinicians to diagnose their undiagnosed patients has not yet been matched by genetics-based decision-support systems for treatment guidance. Generating a ‘treatabolome’ of treatable variants and the evidence for the treatment has the potential to increase treatment rates for treatable conditions. Here, we use the congenital myasthenic syndromes (CMS), a group of clinically and genetically heterogeneous but frequently treatable neuromuscular conditions, to illustrate the steps in the creation of a treatabolome for rare inherited diseases. We perform a systematic review of the evidence for pharmacological treatment of each CMS type, gathering evidence from 207 studies of over 1000 patients and stratifying by genetic defect, as treatment varies depending on the underlying cause. We assess the strength and quality of the evidence and create a dataset that provides the foundation for a computer-aided system to enable clinicians to gain easier access to information about treatable variants and the evidence they need to consider.
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Tiziano FD, Lomastro R, Abiusi E, Pasanisi MB, Di Pietro L, Fiori S, Baranello G, Angelini C, Sorarù G, Gaiani A, Mongini T, Vercelli L, Mercuri E, Vasco G, Pane M, Vita G, Vita G, Messina S, Petillo R, Passamano L, Politano L, Campanella A, Mantegazza R, Morandi L. Longitudinal evaluation of SMN levels as biomarker for spinal muscular atrophy: results of a phase IIb double-blind study of salbutamol. J Med Genet 2018; 56:293-300. [DOI: 10.1136/jmedgenet-2018-105482] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 11/10/2018] [Accepted: 11/30/2018] [Indexed: 11/04/2022]
Abstract
BackgroundSpinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder, due to the loss of function of the survival motor neuron (SMN1) gene. The first treatment for the condition, recently approved, is based on the reduction of exon 7 skipping in mRNAs produced by a highly homologous gene (SMN2). The primary objective of the present study was to evaluate the applicability of the dosage of SMN gene produts in blood, as biomarker for SMA, and the safety of oral salbutamol, a beta2-adrenergic agonist modulating SMN2 levels.MethodsWe have performed a 1-year multicentre, double-blind, placebo-controlled study with salbutamol in 45 adult patients with SMA. Patients assumed 4 mg of salbutamol or placebo/three times a day. Molecular tests were SMN2 copy number, SMN transcript and protein levels. We have also explored the clinical effect, by the outcome measures available at the time of study design.ResultsThirty-six patients completed the study. Salbutamol was safe and well tolerated. We observed a significant and progressive increase in SMN2 full-length levels in peripheral blood of the salbutamol-treated patients (p<0.00001). The exploratory analysis of motor function showed an improvement in most patients.ConclusionsOur data demonstrate safety and molecular efficacy of salbutamol. We provide the first longitudinal evaluation of SMN levels (both transcripts and protein) in placebo and in response to a compound modulating the gene expression: SMN transcript dosage in peripheral blood is reliable and may be used as pharmacodynamic marker in clinical trials with systemic compounds modifying SMN2levels.Trial registration numberEudraCT no. 2007-001088-32.
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30
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Italian recommendations for diagnosis and management of congenital myasthenic syndromes. Neurol Sci 2018; 40:457-468. [PMID: 30554356 DOI: 10.1007/s10072-018-3682-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/10/2018] [Indexed: 12/11/2022]
Abstract
Congenital myasthenic syndromes (CMS) are genetic disorders due to mutations in genes encoding proteins involved in the neuromuscular junction structure and function. CMS usually present in young children, but perinatal and adult onset has been reported. Clinical presentation is highly heterogeneous, ranging from mild symptoms to severe manifestations, sometimes with life-threatening respiratory episodes, especially in the first decade of life. Although considered rare, CMS are probably underestimated due to diagnostic difficulties. Because of the several therapeutic opportunities, CMS should be always considered in the differential diagnosis of neuromuscular disorders. The Italian Network on CMS proposes here recommendations for proper CMS diagnosis and management, aiming to guide clinicians in their practical approach to CMS patients.
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Clausen L, Cossins J, Beeson D. Beta-2 Adrenergic Receptor Agonists Enhance AChR Clustering in C2C12 Myotubes: Implications for Therapy of Myasthenic Disorders. J Neuromuscul Dis 2018; 5:231-240. [PMID: 29865088 PMCID: PMC6004912 DOI: 10.3233/jnd-170293] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background: Congenital myasthenic syndromes (CMS) are a group of inherited neuromuscular transmission disorders causing fatiguable muscle weakness. ADRB2 agonists have been observed to provide therapeutic benefit where destabilisation of NMJ structures is part of the underlying pathology, such as in DOK7, COLQ and MuSK CMS as well as in slow channel syndrome. However, very little is known about the molecular mechanisms underlying the effects of ADRB2 agonists in CMS. Objective: In vitro investigation into whether an ADRB2 agonist affects the AChR clustering pathway and has the potential to increase the number and stability of AChR clusters. Methods: Cultured C2C12 mouse myotubes overexpressing the common DOK7 frameshift mutation c.1124_1127dupTGCC were incubated with salbutamol sulphate and the effect on AChR cluster numbers were investigated. Moreover, agrin-induced AChR clusters in C2C12 WT cells were left to disperse after agrin-wash-off, and the effects of incubation with salbutamol sulphate on AChR cluster numbers were explored. Results: Salbutamol sulphate induced a significant increase in the number of AChR clusters formed on C2C12 cells overexpressing c.1124_1127dupTGCC. Furthermore, significantly more clusters remained in C2C12 WT myotubes incubated with salbutamol sulphate following agrin wash-off. Conclusions: The results suggest that ADRB2 agonists directly affect proteins located at the neuromuscular junction and exert a stabilising effect on AChR clusters.
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Affiliation(s)
- Lisa Clausen
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK
| | - Judith Cossins
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK
| | - David Beeson
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Headley Way, Oxford, UK
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Exome sequencing for paediatric-onset diseases: impact of the extensive involvement of medical geneticists in the diagnostic odyssey. NPJ Genom Med 2018; 3:19. [PMID: 30109123 PMCID: PMC6079040 DOI: 10.1038/s41525-018-0056-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 06/05/2018] [Accepted: 06/11/2018] [Indexed: 11/23/2022] Open
Abstract
Currently, offering whole-exome sequencing (WES) via collaboration with an external laboratory is increasingly common. However, the receipt of a WES report can be merely the beginning of a continuing exploration process rather than the end of the diagnostic odyssey. The laboratory often does not have the information the physician has, and any discrepancies in variant interpretation must be addressed by a medical geneticist. In this study, we performed diagnostic WES of 104 patients with paediatric-onset genetic diseases. The post-exome review of WES reports by the clinical geneticist led to a more comprehensive assessment of variant pathogenicity in 16 cases. The overall diagnostic yield was 41% (n = 43). Among these 43 diagnoses, 51% (22/43) of the pathogenic variants were nucleotide changes that have not been previously reported. The time required for the post-exome review of the WES reports varied, and 26% (n = 27) of the reports required an extensive amount of time (>3 h) for the geneticist to review. In this predominantly Chinese cohort, we highlight the importance of discrepancies between global and ethnic-specific frequencies of a genetic variant that complicate variant interpretation and the significance of post-exome diagnostic modalities in genetic diagnosis using WES. The challenges faced by geneticists in interpreting WES reports are also discussed. In-depth reviews by clinical geneticists can improve the diagnostic accuracy of exome sequencing data for children with unexplained genetic disorders, especially in non-Western populations that are under-represented in genomic databases. Working with children predominantly of Han Chinese origin, Brian Chung from the University of Hong Kong and coworkers sequenced the entire protein-coding portion of the genome for 104 patients with pediatric-onset genetic disease. Specially trained geneticists analyzed the DNA data to resolve any ambiguous interpretations, link the molecular findings with clinical records, identify ethnic-specific differences and, when necessary, request additional assays. This extra review process was sometimes laborious, taking several hours of the physician’s time, but ultimately led to a more comprehensive assessment in 16 of the 43 diagnoses successfully made. This overall diagnostic yield—41%—was comparable to previous studies in other populations.
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Farmakidis C, Pasnoor M, Barohn RJ, Dimachkie MM. Congenital Myasthenic Syndromes: a Clinical and Treatment Approach. Curr Treat Options Neurol 2018; 20:36. [DOI: 10.1007/s11940-018-0520-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Rodríguez Cruz PM, Palace J, Beeson D. The Neuromuscular Junction and Wide Heterogeneity of Congenital Myasthenic Syndromes. Int J Mol Sci 2018; 19:ijms19061677. [PMID: 29874875 PMCID: PMC6032286 DOI: 10.3390/ijms19061677] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 01/16/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are genetic disorders characterised by impaired neuromuscular transmission. This review provides an overview on CMS and highlights recent advances in the field, including novel CMS causative genes and improved therapeutic strategies. CMS due to mutations in SLC5A7 and SLC18A3, impairing the synthesis and recycling of acetylcholine, have recently been described. In addition, a novel group of CMS due to mutations in SNAP25B, SYT2, VAMP1, and UNC13A1 encoding molecules implicated in synaptic vesicles exocytosis has been characterised. The increasing number of presynaptic CMS exhibiting CNS manifestations along with neuromuscular weakness demonstrate that the myasthenia can be only a small part of a much more extensive disease phenotype. Moreover, the spectrum of glycosylation abnormalities has been increased with the report that GMPPB mutations can cause CMS, thus bridging myasthenic disorders with dystroglycanopathies. Finally, the discovery of COL13A1 mutations and laminin α5 deficiency has helped to draw attention to the role of extracellular matrix proteins for the formation and maintenance of muscle endplates. The benefit of β2-adrenergic agonists alone or combined with pyridostigmine or 3,4-Dyaminopiridine is increasingly being reported for different subtypes of CMS including AChR-deficiency and glycosylation abnormalities, thus expanding the therapeutic repertoire available.
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Affiliation(s)
- Pedro M Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford OX3 9DS, UK.
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford OX3 9DS, UK.
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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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Estephan EDP, Sobreira CFDR, Dos Santos ACJ, Tomaselli PJ, Marques W, Ortega RPM, Costa MCM, da Silva AMS, Mendonça RH, Caldas VM, Zambon AA, Abath Neto O, Marchiori PE, Heise CO, Reed UC, Azuma Y, Töpf A, Lochmüller H, Zanoteli E. A common CHRNE mutation in Brazilian patients with congenital myasthenic syndrome. J Neurol 2018; 265:708-713. [PMID: 29383513 PMCID: PMC7115868 DOI: 10.1007/s00415-018-8736-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/16/2017] [Accepted: 01/04/2018] [Indexed: 11/29/2022]
Abstract
The most common causes of congenital myasthenic syndromes (CMS) are CHRNE mutations, and some pathogenic allelic variants in this gene are especially frequent in certain ethnic groups. In the southern region of Brazil, a study found the c.130dupG CHRNE mutation in up to 33% of families with CMS. Here, we aimed to verify the frequency of this mutation among individuals with CMS in a larger cohort of CMS patients from different areas of Brazil and to characterize clinical features of these patients. Eighty-four patients with CMS, from 72 families, were clinically evaluated and submitted to direct sequencing of the exon 2 of CHRNE. The c.130dupG mutation was found in 32 patients (23 families), with 26 patients (19 families, 26.3%) in homozygosis, confirming its high prevalence in different regions of Brazil. Among the homozygous patients, the following characteristics were frequent: onset of symptoms before 2 years of age (92.3%), little functional restriction (92.3%), fluctuating symptoms (100%), ocular muscle impairment (96.1%), ptosis (100%), limb weakness (88.4%), response to pyridostigmine (100%), facial involvement (77%), and bulbar symptoms (70.8%). The pretest probability of finding at least one allele harbouring the c.130dupG mutation was 38.1%. Selecting only patients with impaired eye movement together with limb weakness and improvement with pyridostigmine, the probability increases to 72.2%. This clinical pre-selection of patients is likely a useful tool for regions where CHRNE mutations have a founder effect. In conclusion, the CHRNE mutation c.130dupG leads to fairly benign natural course of the disease with relative homogeneity.
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Affiliation(s)
- Eduardo de Paula Estephan
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | | | | | - Pedro José Tomaselli
- Department of Neurosciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Wilson Marques
- Department of Neurosciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | | | - André Macedo Serafim da Silva
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Rodrigo Holanda Mendonça
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Vitor Marques Caldas
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Antonio Alberto Zambon
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Osório Abath Neto
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Paulo Eurípedes Marchiori
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Carlos Otto Heise
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Umbertina Conti Reed
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Yoshiteru Azuma
- Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Ana Töpf
- Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Hanns Lochmüller
- Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil.
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Lee M, Beeson D, Palace J. Therapeutic strategies for congenital myasthenic syndromes. Ann N Y Acad Sci 2018; 1412:129-136. [DOI: 10.1111/nyas.13538] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/28/2017] [Accepted: 10/02/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Manon Lee
- Nuffield Department of Clinical Neurosciences; John Radcliffe Hospital; Oxford United Kingdom
| | - David Beeson
- The Weatherall Institute of Molecular Medicine, John Radcliffe Hospital; University of Oxford; Oxford United Kingdom
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences; John Radcliffe Hospital; Oxford United Kingdom
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Abstract
PURPOSE OF REVIEW Congenital myasthenic syndromes (CMS) are a group of heterogeneous inherited disorders caused by mutations in genes encoding proteins essential for the integrity of neuromuscular transmission. This review updates the reader on recent findings that have expanded the phenotypic spectrum and suggested improved treatment strategies. RECENT FINDINGS The use of next-generation sequencing is continuing to unearth new genes in which mutations can give rise to defective neuromuscular transmission. The defective transmission may be part of an overall more complex phenotype in which there may be muscle, central nervous system or other involvement. Notably, mutations in series of genes encoding presynaptic proteins are being identified. Further work on mutations found in the AGRN-MUSK acetylcholine receptor clustering pathway has helped characterize the role of LRP4 and broadened the phenotypic spectrum for AGRN mutations. Mutations in another extracellular matrix protein, collagen 13A1 and in GMPPB have also been found to cause a CMS. Finally, there are an increasing number of reports for the beneficial effects of treatment with β2-adrenergic receptor agonists. SUMMARY Recent studies of the CMS illustrate the increasing complexity of the genetics, pathophysiological mechanisms and the need to tailor therapy for the genetic disorders of the neuromuscular junction.
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Bosak A, Knežević A, Gazić Smilović I, Šinko G, Kovarik Z. Resorcinol-, catechol- and saligenin-based bronchodilating β2-agonists as inhibitors of human cholinesterase activity. J Enzyme Inhib Med Chem 2017; 32:789-797. [PMID: 28573890 PMCID: PMC6445159 DOI: 10.1080/14756366.2017.1326109] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 04/13/2017] [Accepted: 04/21/2017] [Indexed: 12/19/2022] Open
Abstract
We investigated the influence of bronchodilating β2-agonists on the activity of human acetylcholinesterase (AChE) and usual, atypical and fluoride-resistant butyrylcholinesterase (BChE). We determined the inhibition potency of racemate and enantiomers of fenoterol as a resorcinol derivative, isoetharine and epinephrine as catechol derivatives and salbutamol and salmeterol as saligenin derivatives. All of the tested compounds reversibly inhibited cholinesterases with Ki constants ranging from 9.4 μM to 6.4 mM and had the highest inhibition potency towards usual BChE, but generally none of the cholinesterases displayed any stereoselectivity. Kinetic and docking results revealed that the inhibition potency of the studied compounds could be related to the size of the hydroxyaminoethyl chain on the benzene ring. The additional π-π interaction of salmeterol's benzene ring and Trp286 and hydrogen bond with His447 probably enhanced inhibition by salmeterol which was singled out as the most potent inhibitor of all the cholinesterases.
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Affiliation(s)
- Anita Bosak
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | | | | | - Goran Šinko
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
| | - Zrinka Kovarik
- Institute for Medical Research and Occupational Health, Zagreb, Croatia
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Ghosh PS. Clinical Reasoning: A child with delayed motor milestones and ptosis. Neurology 2017; 88:e158-e163. [DOI: 10.1212/wnl.0000000000003844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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A Novel Missense Variant in the AGRN Gene; Congenital Myasthenic Syndrome Presenting With Head Drop. J Clin Neuromuscul Dis 2017; 18:147-151. [PMID: 28221305 DOI: 10.1097/cnd.0000000000000132] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Congenital myasthenic syndromes (CMS) are a heterogeneous group of diseases of the neuromuscular junction caused by compromised synaptic transmission. Clinical features include early-onset weakness of limbs and oculobulbar muscles resulting in hypotonia, bulbar paresis, ptosis, and hypoventilation. The first dropped head syndrome in children were detected in 2 patients with LMNA and SEPN1 mutations. We report a 17-month-old boy with dropped head and limb-girdle weakness, who had no ptosis or ophthalmoplegia at presentation. We performed whole exome sequencing, which revealed a homozygous missense variant in the AGRN gene c.5023G>A, p.Gly1675Ser in the LG2 domain, which is predicted to be likely disease causing by in silico tools. Agrin is known to play a critical role in the development and maintenance of the neuromuscular junction. Agrin-related CMS is one of the rarest subtypes. Of note, our patient is the first described patient with agrin-related CMS with dropped head phenotype.
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Lipka AF, Vrinten C, van Zwet EW, Schimmel KJ, Cornel MC, Kuijpers MR, Hekster YA, Weinreich SS, Verschuuren JJ. Ephedrine treatment for autoimmune myasthenia gravis. Neuromuscul Disord 2017; 27:259-265. [DOI: 10.1016/j.nmd.2016.11.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 11/09/2016] [Accepted: 11/14/2016] [Indexed: 11/27/2022]
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Chang T, Cossins J, Beeson D. A rare c.183_187dupCTCAC mutation of the acetylcholine receptor CHRNE gene in a South Asian female with congenital myasthenic syndrome: a case report. BMC Neurol 2016; 16:195. [PMID: 27717316 PMCID: PMC5055717 DOI: 10.1186/s12883-016-0716-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 09/30/2016] [Indexed: 11/30/2022] Open
Abstract
Background Congenital myasthenic syndromes (CMSs) occur as a result of genetic mutations that cause aberrations in structure and/or function of proteins involved in neuromuscular transmission. Acetylcholine receptor epsilon (ε) subunit (CHRNE) gene mutations account for about 30–50 % of genetically diagnosed cases. We report a rare CHRNE gene mutation in a South Asian female with CMS. Case presentation A 17-year-old Maldivian female presented with bilateral partial ptosis, fatigable proximal muscle weakness and slurring of speech noted since the age of 2 years. She could not run, had difficulty negotiating stairs and rising from a seated position, and fatigues when speaking at length. Her birth and past medical histories were otherwise unremarkable. There is no parental consanguinity or family history of muscle disorders. On examination, she had a BMI of 18 kg/m2, bilateral fatigable partial ptosis, complete external ophthalmoplegia and fatigable proximal muscle weakness (MRC grade 4/5). Apart from spinal scoliosis the rest of the examination was normal. Haematological and biochemical investigations including serum lactate level and thyroid functions were normal. Acetylcholine receptor antibodies and muscle specific kinase antibodies were not detected in serum. Repetitive nerve stimulation showed marked decrement (>30 %) in nerve-muscle pairs in the face and forearm. Her DNA sequencing revealed a c.183-187dupCTCAC mutation in CHRNE. She remained functionally independent on pyridostigmine treatment. Conclusions This case describes a rare mutation of the CHRNE gene in CMS and highlights the relevance of genetic diagnosis in CMS. It further adds to map the occurrence of such mutations in Asian populations.
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Affiliation(s)
- Thashi Chang
- Department of Clinical Medicine, Faculty of Medicine, University of Colombo, 25, Kynsey Road, Colombo 08, Sri Lanka.
| | - Judith Cossins
- Neuromuscular Disorders Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS,, United Kingdom
| | - David Beeson
- Neuromuscular Disorders Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS,, United Kingdom
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