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Fournier JE, Mak G, Gordon K, Glogauer J, Fareez F, Provias J, Tarnopolsky MA, Lu JQ. Cylindrical spirals and other concentric structures of skeletal muscle in patients with neurological diseases. J Neurol Sci 2023; 451:120734. [PMID: 37478793 DOI: 10.1016/j.jns.2023.120734] [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: 03/30/2023] [Revised: 07/07/2023] [Accepted: 07/11/2023] [Indexed: 07/23/2023]
Abstract
Cylindrical spirals (CSs) are ultrastructurally distinct, intracytoplasmic inclusions characterized by concentrically wrapped lamellae, which are rarely found in skeletal muscle biopsies on electron microscopy (EM). CSs are often confused with other EM concentric structures including concentric laminated bodies and mitochondrial concentric cristae (MCC), due to similarities in these ultrastructures. In this study, we found CSs in 9 muscle biopsies from 9 patients, accounting for 0.5% of the biopsies examined routinely by EM. The frequency of CSs in these muscles varied from sparse and segregated to focally frequent and aggregated. CS-associated features included muscle fiber denervation atrophy in all 9 cases, fiber type grouping in 7/8 cases, tubular aggregates in 3/9 cases, and MCC in 2/9 cases. We also compared the concentric structures and highlighted their differences to distinguish CSs from other similar structures. Clinically, 8 out of 9 patients were adults aged 41-74 years and only one patient was 17 month-old. CSs were associated with several neurological diseases including Huntington's disease, amyotrophic lateral sclerosis, Mitochondrial Encephalopathy, Lactic Acidosis, and Stroke-like episodes, and other complex neurological disorders with neuropathy/encephalopathy, as well as anti-MDA5+ dermatomyositis. Eight of nine patients had genetic findings such as trinucleotide repeat expansion of huntingtin gene, ALS2 variant, MT-TL1 m.3243A > G mutation, and PMP 22 gene deletion. These results suggest that CSs may be highly variable in frequency and likely are under-reported/under-detected; they may be associated with neurogenic myopathy or central/peripheral nervous system disorders including some genetic neurological/neuromuscular diseases. Our findings of more CS-associated neurological diseases and an association of CSs with muscle neurogenic features may contribute to a better understanding of the clinico-pathological significance of CSs.
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Affiliation(s)
- Jeffrey E Fournier
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Gloria Mak
- Department of Medicine/Neurology, McMaster University, Hamilton, Ontario, Canada
| | - Katerina Gordon
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Judah Glogauer
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Faiha Fareez
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - John Provias
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
| | - Mark A Tarnopolsky
- Department of Medicine/Neurology, McMaster University, Hamilton, Ontario, Canada; Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada
| | - Jian-Qiang Lu
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.
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[Neuropathology I: muscular diseases]. PATHOLOGIE (HEIDELBERG, GERMANY) 2023; 44:104-112. [PMID: 36459202 PMCID: PMC9984347 DOI: 10.1007/s00292-022-01163-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/10/2022] [Indexed: 12/03/2022]
Abstract
Muscle diseases include hereditary and acquired diseases with clinical manifestation in both childhood and adulthood. The different muscle diseases may have ultrastructural alterations that help us further understand the pathology of the disease. Specific changes in sarcomere structure help to classify a congenital myopathy. The detection of cellular aggregates supports the classification of myositis. Pathologically altered mitochondria, on the other hand, can occur both in genetic mitochondriopathies but also secondarily in acquired muscle diseases like myositis. Ultrastructural analysis of the myocardium is also helpful in the diagnosis of hereditary cardiomyopathies in childhood. This review article highlights the ultrastructural features of different muscle diseases and pathognomonic findings in specific disease groups.
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Selvais CM, Davis-López de Carrizosa MA, Nachit M, Versele R, Dubuisson N, Noel L, Gillard J, Leclercq IA, Brichard SM, Abou-Samra M. AdipoRon enhances healthspan in middle-aged obese mice: striking alleviation of myosteatosis and muscle degenerative markers. J Cachexia Sarcopenia Muscle 2023; 14:464-478. [PMID: 36513619 PMCID: PMC9891981 DOI: 10.1002/jcsm.13148] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 11/16/2022] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Obesity among older adults has increased tremendously. Obesity accelerates ageing and predisposes to age-related conditions and diseases, such as loss of endurance capacity, insulin resistance and features of the metabolic syndrome. Namely, ectopic lipids play a key role in the development of nonalcoholic fatty liver disease (NAFLD) and myosteatosis, two severe burdens of ageing and metabolic diseases. Adiponectin (ApN) is a hormone, mainly secreted by adipocytes, which exerts insulin-sensitizing and fat-burning properties in several tissues including the liver and the muscle. Its overexpression also increases lifespan in mice. In this study, we investigated whether an ApN receptor agonist, AdipoRon (AR), could slow muscle dysfunction, myosteatosis and degenerative muscle markers in middle-aged obese mice. The effects on myosteatosis were compared with those on NAFLD. METHODS Three groups of mice were studied up to 62 weeks of age: One group received normal diet (ND), another, high-fat diet (HFD); and the last, HFD combined with AR given orally for almost 1 year. An additional group of young mice under an ND was used. Treadmill tests and micro-computed tomography (CT) were carried out in vivo. Histological, biochemical and molecular analyses were performed on tissues ex vivo. Bodipy staining was used to assess intramyocellular lipid (IMCL) and lipid droplet morphology. RESULTS AR did not markedly alter diet-induced obesity. Yet, this treatment rescued exercise endurance in obese mice (up to 2.4-fold, P < 0.05), an event that preceded the improvement of insulin sensitivity. Dorsal muscles and liver densities, measured by CT, were reduced in obese mice (-42% and -109%, respectively, P < 0.0001), suggesting fatty infiltration. This reduction tended to be attenuated by AR. Accordingly, AR significantly mitigated steatosis and cellular ballooning at liver histology, thereby decreasing the NALFD activity score (-30%, P < 0.05). AR also strikingly reversed IMCL accumulation either due to ageing in oxidative fibres (types 1/2a, soleus) or to HFD in glycolytic ones (types 2x/2b, extensor digitorum longus) (-50% to -85%, P < 0.05 or less). Size of subsarcolemmal lipid droplets, known to be associated with adverse metabolic outcomes, was reduced as well. Alleviation of myosteatosis resulted from improved mitochondrial function and lipid oxidation. Meanwhile, AR halved aged-related accumulation of dysfunctional proteins identified as tubular aggregates and cylindrical spirals by electron microscopy (P < 0.05). CONCLUSIONS Long-term AdipoRon treatment promotes 'healthy ageing' in obese middle-aged mice by enhancing endurance and protecting skeletal muscle and liver against the adverse metabolic and degenerative effects of ageing and caloric excess.
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Affiliation(s)
- Camille M Selvais
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - María A Davis-López de Carrizosa
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium.,Department of Physiology, Faculty of Biology, University of Seville, Seville, Spain
| | - Maxime Nachit
- Hepato-Gastroenterology Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Romain Versele
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Nicolas Dubuisson
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Laurence Noel
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Justine Gillard
- Hepato-Gastroenterology Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Isabelle A Leclercq
- Hepato-Gastroenterology Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Sonia M Brichard
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
| | - Michel Abou-Samra
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, UCLouvain, Brussels, Belgium
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Vattemi GNA, Rossi D, Galli L, Catallo MR, Pancheri E, Marchetto G, Cisterna B, Malatesta M, Pierantozzi E, Tonin P, Sorrentino V. Ryanodine receptor 1 (RYR1) mutations in two patients with tubular aggregate myopathy. Eur J Neurosci 2022; 56:4214-4223. [PMID: 35666680 PMCID: PMC9539902 DOI: 10.1111/ejn.15728] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Revised: 05/24/2022] [Accepted: 05/24/2022] [Indexed: 11/30/2022]
Abstract
Two likely causative mutations in the RYR1 gene were identified in two patients with myopathy with tubular aggregates, but no evidence of cores or core‐like pathology on muscle biopsy. These patients were clinically evaluated and underwent routine laboratory investigations, electrophysiologic tests, muscle biopsy and muscle magnetic resonance imaging (MRI). They reported stiffness of the muscles following sustained activity or cold exposure and had serum creatine kinase elevation. The identified RYR1 mutations (p.Thr2206Met or p.Gly2434Arg, in patient 1 and patient 2, respectively) were previously identified in individuals with malignant hyperthermia susceptibility and are reported as causative according to the European Malignant Hyperthermia Group rules. To our knowledge, these data represent the first identification of causative mutations in the RYR1 gene in patients with tubular aggregate myopathy and extend the spectrum of histological alterations caused by mutation in the RYR1 gene.
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Affiliation(s)
- Gaetano Nicola Alfio Vattemi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Daniela Rossi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Lucia Galli
- Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
| | - Maria Rosaria Catallo
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy
| | - Elia Pancheri
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Giulia Marchetto
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Clinical Neurology, University of Verona, Verona, Italy
| | - Barbara Cisterna
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy
| | - Manuela Malatesta
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy
| | - Enrico Pierantozzi
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy
| | - Paola Tonin
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Anatomy and Histology, University of Verona, Verona, Italy
| | - Vincenzo Sorrentino
- Department of Molecular and Developmental Medicine, Molecular Medicine Section, University of Siena, Siena, Italy.,Interdepartmental Program of Molecular Diagnosis and Pathogenetic Mechanisms of Rare Genetic Diseases, Azienda Ospedaliero Universitaria Senese, Siena, Italy
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5
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Gang Q, Bettencourt C, Brady S, Holton JL, Healy EG, McConville J, Morrison PJ, Ripolone M, Violano R, Sciacco M, Moggio M, Mora M, Mantegazza R, Zanotti S, Wang Z, Yuan Y, Liu WW, Beeson D, Hanna M, Houlden H. Genetic defects are common in myopathies with tubular aggregates. Ann Clin Transl Neurol 2021; 9:4-15. [PMID: 34908252 PMCID: PMC8791796 DOI: 10.1002/acn3.51477] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/12/2021] [Accepted: 10/27/2021] [Indexed: 12/17/2022] Open
Abstract
Objective A group of genes have been reported to be associated with myopathies with tubular aggregates (TAs). Many cases with TAs still lack of genetic clarification. This study aims to explore the genetic background of cases with TAs in order to improve our knowledge of the pathogenesis of these rare pathological structures. Methods Thirty‐three patients including two family members with biopsy confirmed TAs were collected. Whole‐exome sequencing was performed on 31 unrelated index patients and a candidate gene search strategy was conducted. The identified variants were confirmed by Sanger sequencing. The wild‐type and the mutant p.Ala11Thr of ALG14 were transfected into human embryonic kidney 293 cells (HEK293), and western blot analysis was performed to quantify protein expression levels. Results Eleven index cases (33%) were found to have pathogenic variant or likely pathogenic variants in STIM1, ORAI1, PGAM2, SCN4A, CASQ1 and ALG14. Among them, the c.764A>T (p.Glu255Val) in STIM1 and the c.1333G>C (p.Val445Leu) in SCN4A were novel. Western blot analysis showed that the expression of ALG14 protein was severely reduced in the mutant ALG14 HEK293 cells (p.Ala11Thr) compared with wild type. The ALG14 variants might be associated with TAs in patients with complex multisystem disorders. Interpretation This study expands the phenotypic and genotypic spectrums of myopathies with TAs. Our findings further confirm previous hypothesis that genes related with calcium signalling pathway and N‐linked glycosylation pathway are the main genetic causes of myopathies with TAs.
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Affiliation(s)
- Qiang Gang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, 100034, China.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - Conceição Bettencourt
- Queen Square Brain Bank for Neurological Disorders, London, UK.,Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - Stefen Brady
- Oxford Muscle Service, John Radcliffe Hospital, Oxford, UK
| | - Janice L Holton
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,Queen Square Brain Bank for Neurological Disorders, London, UK
| | - Estelle G Healy
- Department of Neuropathology, Royal Victoria Hospital, Belfast, Northern Ireland
| | - John McConville
- Department of Neurology, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Patrick J Morrison
- Department of Genetic Medicine, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Michela Ripolone
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Raffaella Violano
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Monica Sciacco
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Maurizio Moggio
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Marina Mora
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Isitituto Neurologico C. Besta, Milano, Italy
| | - Renato Mantegazza
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Isitituto Neurologico C. Besta, Milano, Italy
| | - Simona Zanotti
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Isitituto Neurologico C. Besta, Milano, Italy
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, 100034, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, 100034, China
| | - Wei-Wei Liu
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - David Beeson
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Michael Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,Neurogenetics Laboratory, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
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Beecroft SJ, Olive M, Quereda LG, Gallano P, Ojanguren I, McLean C, McCombe P, Laing NG, Ravenscroft G. Cylindrical spirals in two families: Clinical and genetic investigations. Neuromuscul Disord 2019; 30:151-158. [PMID: 31952901 DOI: 10.1016/j.nmd.2019.12.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/17/2019] [Accepted: 12/19/2019] [Indexed: 01/19/2023]
Abstract
Cylindrical spirals are a rare ultrastructural finding on muscle biopsy, with fewer than 20 reported cases since its first description in 1979. These structures are sometimes observed with tubular aggregates and are thought to comprise longitudinal sarcoplasmic reticulum. While mutations in genes encoding key components of Ca2+ handling (ORAI1 and STIM1) underlie tubular aggregate myopathy, no causative genes have been associated with cylindrical spirals. Here we describe two families with cylindrical spirals on muscle biopsy with a suspected genetic cause. In one family we identified a known truncating variant in EBF3, previously associated with a neurodevelopmental disorder. The affected individuals in this family present with clinical features overlapping with those described for EBF3 disease. An isolated proband in the second family harbours bi-allelic truncating variants in TTN and her clinical course and other features on biopsy are highly concordant for titinopathy. From experimental studies, EBF3 is known to be involved in Ca2+ regulation in muscle, thus EBF3 dysregulation may represent a novel mechanism of impaired Ca2+ handling leading to cylindrical spirals. Additional cases of EBF3 disease or titinopathy with cylindrical spirals need to be identified to support the involvement of these genes in the pathogenesis of cylindrical spirals.
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Affiliation(s)
- Sarah J Beecroft
- Centre for Medical Research, University of Western Australia, Harry Perkins Institute of Medical Research, QEII Medical Centre, Australia
| | - Montse Olive
- Neuropathology Unit, Department of Pathology and Neuromuscular Unit, Department of Neurology, IDIBELL-Hospital de Bellvitge, Hospitalet de Llobregat, Barcelona 08907, Spain
| | | | - Pia Gallano
- CIBERER, Genetics Department, Hospital Sant Pau, Barcelona 08041, Spain
| | - Isabel Ojanguren
- Department of Pathology, Hospital Germans Trias i Pujol, Badalona 08916, Spain
| | - Catriona McLean
- Victorian Neuromuscular Laboratory, Alfred Health, Commercial Rd, Prahran, VIC 3181, Australia
| | - Pamela McCombe
- The University of Queensland Centre for Clinical Research, Royal Brisbane and Women's Hospital, Brisbane, Australia
| | - Nigel G Laing
- Centre for Medical Research, University of Western Australia, Harry Perkins Institute of Medical Research, QEII Medical Centre, Australia
| | - Gianina Ravenscroft
- Centre for Medical Research, University of Western Australia, Harry Perkins Institute of Medical Research, QEII Medical Centre, Australia.
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Bugiardini E, Khan AM, Phadke R, Lynch DS, Cortese A, Feng L, Gang Q, Pittman AM, Morrow JM, Turner C, Carr AS, Quinlivan R, Rossor AM, Holton JL, Parton M, Blake JC, Reilly MM, Houlden H, Matthews E, Hanna MG. Genetic and phenotypic characterisation of inherited myopathies in a tertiary neuromuscular centre. Neuromuscul Disord 2019; 29:747-757. [DOI: 10.1016/j.nmd.2019.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/12/2019] [Accepted: 08/09/2019] [Indexed: 02/06/2023]
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Nicolau S, Kao JC, Liewluck T. Trouble at the junction: When myopathy and myasthenia overlap. Muscle Nerve 2019; 60:648-657. [PMID: 31449669 DOI: 10.1002/mus.26676] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/18/2019] [Accepted: 08/20/2019] [Indexed: 12/22/2022]
Abstract
Although myopathies and neuromuscular junction disorders are typically distinct, their coexistence has been reported in several inherited and acquired conditions. Affected individuals have variable clinical phenotypes but typically display both a decrement on repetitive nerve stimulation and myopathic findings on muscle biopsy. Inherited causes include myopathies related to mutations in BIN1, DES, DNM2, GMPPB, MTM1, or PLEC and congenital myasthenic syndromes due to mutations in ALG2, ALG14, COL13A1, DOK7, DPAGT1, or GFPT1. Additionally, a decrement due to muscle fiber inexcitability is observed in certain myotonic disorders. The identification of a defect of neuromuscular transmission in an inherited myopathy may assist in establishing a molecular diagnosis and in selecting patients who would benefit from pharmacological correction of this defect. Acquired cases meanwhile stem from the co-occurrence of myasthenia gravis or Lambert-Eaton myasthenic syndrome with an immune-mediated myopathy, which may be due to paraneoplastic disorders or exposure to immune checkpoint inhibitors.
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Affiliation(s)
- Stefan Nicolau
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Justin C Kao
- Department of Neurology, Auckland City Hospital, Auckland, New Zealand
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Mutations in GFPT1-related congenital myasthenic syndromes are associated with synaptic morphological defects and underlie a tubular aggregate myopathy with synaptopathy. J Neurol 2017; 264:1791-1803. [DOI: 10.1007/s00415-017-8569-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 07/03/2017] [Accepted: 07/11/2017] [Indexed: 12/22/2022]
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