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Vacchiano V, Brugnoni R, Campanale C, Imbrici P, Dinoi G, Canioni E, Laghetti P, Saltarella I, Altamura C, Maggi L, Liguori R, Donadio V, Desaphy JF. Coexistence of SCN4A and CLCN1 mutations in a family with atypical myotonic features: A clinical and functional study. Exp Neurol 2023; 362:114342. [PMID: 36720299 DOI: 10.1016/j.expneurol.2023.114342] [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: 11/06/2022] [Revised: 01/12/2023] [Accepted: 01/26/2023] [Indexed: 01/30/2023]
Abstract
Non-dystrophic myotonias include several entities with possible clinical overlap, i.e. myotonia congenita caused by CLCN1 gene mutations, as well as paramyotonia congenita and sodium channel myotonia caused by SCN4A gene mutations. Herein, we describe the clinical features of five relatives affected by clinical and neurophysiological myotonia, with an aspecific and mixed phenotype. Next-generation sequencing identified the novel p.K1302R variant in SCN4A and the p.H838P variant in CLCN1. Segregation of the two mutations with the disease was confirmed by genotyping affected and non-affected family members. Patch-clamp experiments showed that sodium currents generated by p.K1302R and WT hNav1.4 were very similar. Mutant channel showed a small negative shift (5 mV) in the voltage-dependence of activation, which increased the likelihood of the channel to open at more negative voltages. The p.H838P mutation caused a reduction in chloride current density and a small voltage-dependence shift towards less negative potentials, in agreement with its position into the CBS2 domain of the C-terminus. Our results demonstrated that the mild functional alterations induced by p.K1302R and p.H838P in combination may be responsible for the mixed myotonic phenotypes. The K1302R mutant was sensitive to mexiletine and lamotrigine, suggesting that both drugs might be useful for the K1302R carriers.
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Affiliation(s)
- Veria Vacchiano
- IRCSS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy.
| | - Raffaella Brugnoni
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Italy
| | - Carmen Campanale
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Paola Imbrici
- Dept. of Pharmacy - Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Giorgia Dinoi
- Dept. of Pharmacy - Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Eleonora Canioni
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Italy
| | - Paola Laghetti
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Ilaria Saltarella
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Concetta Altamura
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
| | - Lorenzo Maggi
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Italy
| | - Rocco Liguori
- IRCSS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Vincenzo Donadio
- IRCSS Istituto delle Scienze Neurologiche di Bologna, Bologna, Italy
| | - Jean-François Desaphy
- Dept. of Precision and Regenerative Medicine, School of Medicine, University of Bari Aldo Moro, Bari, Italy
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Pedersen TH, Macdonald WA, Broch‐Lips M, Halldorsdottir O, Bækgaard Nielsen O. Chloride channel inhibition improves neuromuscular function under conditions mimicking neuromuscular disorders. Acta Physiol (Oxf) 2021; 233:e13690. [PMID: 34021706 DOI: 10.1111/apha.13690] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/09/2021] [Accepted: 05/16/2021] [Indexed: 10/21/2022]
Abstract
AIM The skeletal muscle Cl- channels, the ClC-1 channels, stabilize the resting membrane potential and dampen muscle fibre excitability. This study explored whether ClC-1 inhibition can recover nerve-stimulated force in isolated muscle under conditions of compromised neuromuscular transmission akin to disorders of myasthenia gravis and Lambert-Eaton syndrome. METHODS Nerve-muscle preparations were isolated from rats. Preparations were exposed to pre-or post-synaptic inhibitors (ω-agatoxin, elevated extracellular Mg2+ , α-bungarotoxin or tubocurarine). The potential of ClC-1 inhibition (9-AC or reduced extracellular Cl- ) to recover nerve-stimulated force under these conditions was assessed. RESULTS ClC-1 inhibition recovered force in both slow-twitch soleus and fast-twitch EDL muscles exposed to 0.2 µmol/L tubocurarine or 3.5 mmol/L Mg2+ . Similarly, ClC-1 inhibition recovered force in soleus muscles exposed to α-bungarotoxin or ω-agatoxin. Moreover, the concentrations of tubocurarine and Mg2+ required for reducing force to 50% rose from 0.14 ± 0.02 µmol/L and 4.2 ± 0.2 mmol/L in control muscles to 0.45 ± 0.03 µmol/L and 4.7 ± 0.3 mmol/L in muscles with 9-AC respectively (P < .05, paired T test). Inhibition of acetylcholinesterase (neostigmine) and inhibition of voltage-gated K+ channels (4-AP) relieve symptoms in myasthenia gravis and Lambert-Eaton syndrome, respectively. Neostigmine and 9-AC additively increased the tubocurarine concentration required to reduce nerve-stimulated force to 50% (0.56 ± 0.05 µmol/L with 9-AC and neostigmine) and, similarly, 4-AP and 9-AC additively increased the Mg2+ concentration required to reduce nerve-stimulated force to 50% (6.5 ± 0.2 mmol/L with 9-AC and 4-AP). CONCLUSION This study shows that ClC-1 inhibition can improve neuromuscular function in pharmacological models of compromised neuromuscular transmission.
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Uwera F, Ammar T, McRae C, Hayward LJ, Renaud JM. Lower Ca2+ enhances the K+-induced force depression in normal and HyperKPP mouse muscles. J Gen Physiol 2021; 152:151656. [PMID: 32291438 PMCID: PMC7335014 DOI: 10.1085/jgp.201912511] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 02/18/2020] [Accepted: 03/21/2020] [Indexed: 12/20/2022] Open
Abstract
Hyperkalemic periodic paralysis (HyperKPP) manifests as stiffness or subclinical myotonic discharges before or during periods of episodic muscle weakness or paralysis. Ingestion of Ca2+ alleviates HyperKPP symptoms, but the mechanism is unknown because lowering extracellular [Ca2+] ([Ca2+]e) has no effect on force development in normal muscles under normal conditions. Lowering [Ca2+]e, however, is known to increase the inactivation of voltage-gated cation channels, especially when the membrane is depolarized. Two hypotheses were tested: (1) lowering [Ca2+]e depresses force in normal muscles under conditions that depolarize the cell membrane; and (2) HyperKPP muscles have a greater sensitivity to low Ca2+-induced force depression because many fibers are depolarized, even at a normal [K+]e. In wild type muscles, lowering [Ca2+]e from 2.4 to 0.3 mM had little effect on tetanic force and membrane excitability at a normal K+ concentration of 4.7 mM, whereas it significantly enhanced K+-induced depression of force and membrane excitability. In HyperKPP muscles, lowering [Ca2+]e enhanced the K+-induced loss of force and membrane excitability not only at elevated [K+]e but also at 4.7 mM K+. Lowering [Ca2+]e increased the incidence of generating fast and transient contractures and gave rise to a slower increase in unstimulated force, especially in HyperKPP muscles. Lowering [Ca2+]e reduced the efficacy of salbutamol, a β2 adrenergic receptor agonist and a treatment for HyperKPP, to increase force at elevated [K+]e. Replacing Ca2+ by an equivalent concentration of Mg2+ neither fully nor consistently reverses the effects of lowering [Ca2+]e. These results suggest that the greater Ca2+ sensitivity of HyperKPP muscles primarily relates to (1) a greater effect of Ca2+ in depolarized fibers and (2) an increased proportion of depolarized HyperKPP muscle fibers compared with control muscle fibers, even at normal [K+]e.
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Affiliation(s)
- Francine Uwera
- University of Ottawa, Department of Cellular and Molecular Medicine, Ottawa, Ontario, Canada
| | - Tarek Ammar
- University of Ottawa, Department of Cellular and Molecular Medicine, Ottawa, Ontario, Canada
| | - Callum McRae
- University of Ottawa, Department of Cellular and Molecular Medicine, Ottawa, Ontario, Canada
| | - Lawrence J Hayward
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA
| | - Jean-Marc Renaud
- University of Ottawa, Department of Cellular and Molecular Medicine, Ottawa, Ontario, Canada
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Stunnenberg BC, LoRusso S, Arnold WD, Barohn RJ, Cannon SC, Fontaine B, Griggs RC, Hanna MG, Matthews E, Meola G, Sansone VA, Trivedi JR, van Engelen BG, Vicart S, Statland JM. Guidelines on clinical presentation and management of nondystrophic myotonias. Muscle Nerve 2020; 62:430-444. [PMID: 32270509 PMCID: PMC8117169 DOI: 10.1002/mus.26887] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/01/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The nondystrophic myotonias are rare muscle hyperexcitability disorders caused by gain-of-function mutations in the SCN4A gene or loss-of-function mutations in the CLCN1 gene. Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. Diagnosis is based on history and examination findings, the presence of electrical myotonia on electromyography, and genetic confirmation. In the absence of genetic confirmation, the diagnosis is supported by detailed electrophysiological testing, exclusion of other related disorders, and analysis of a variant of uncertain significance if present. Symptomatic treatment with a sodium channel blocker, such as mexiletine, is usually the first step in management, as well as educating patients about potential anesthetic complications.
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Affiliation(s)
- Bas C. Stunnenberg
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Samantha LoRusso
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - W. David Arnold
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Richard J. Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
| | - Stephen C. Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Bertrand Fontaine
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Robert C. Griggs
- Department of Neurology, University of Rochester, Rochester, New York
| | - Michael G. Hanna
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Giovanni Meola
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Valeria A. Sansone
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
- Neurorehabilitation Unit, University of Milan, NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milan, Italy
| | - Jaya R. Trivedi
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, Texas
| | | | - Savine Vicart
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Jeffrey M. Statland
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
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Abstract
PURPOSE OF REVIEW This article aims to review the current and upcoming treatment options of primary muscle channelopathies including the non-dystrophic myotonias and periodic paralyses. RECENT FINDINGS The efficacy of mexiletine in the treatment of myotonia is now supported by two randomised placebo-controlled trials, one of which utilised a novel aggregated n-of-1 design. This has resulted in licencing of the drug via orphan drug status. There is also good evidence that mexiletine is well tolerated and safe in this patient group without the need for intensive monitoring. A range of alternative antimyotonic treatment options include lamotrigine, carbamazepine and ranolazine exist with variable evidence base. In vitro studies have shown insight into reasons for treatment failure of some medications with certain genotypes opening the era of mutation-specific therapy such as use of flecainide. In the periodic paralyses, the ability of MRI to distinguish between reversible oedema and irreversible fatty replacement makes it an increasingly useful tool to guide and assess pharmacological treatment. Unfortunately, the striking efficacy of bumetanide in hypokalaemic periodic paralysis animal models was not replicated in a recent pilot study in humans. SUMMARY The treatment of skeletal muscle channelopathies combines dietary and lifestyle advice together with pharmacological interventions. The rarity of these conditions remains a barrier for clinical studies but the example of the aggregated n-of-1 trial of mexiletine shows that innovative trial design can overcome these hurdles. Further research is required to test efficacy of drugs shown to have promising characteristics in preclinical experiments such as safinamide, riluzule and magnesium for myotonia or bumetanide for hypokalaemic periodic paralysis.
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Affiliation(s)
- Nantaporn Jitpimolmard
- Queen Square Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
- Rehabilitation Medicine Department, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
| | - Emma Matthews
- Queen Square Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
- Atkinson-Morley Neuromuscular Centre, St George’s University Hospitals Foundation Trust, London, UK
| | - Doreen Fialho
- Queen Square Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, UCL, London, UK
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Hoppe K, Chaiklieng S, Lehmann-Horn F, Jurkat-Rott K, Wearing S, Klingler W. Preclinical pharmacological in vitro investigations on low chloride conductance myotonia: effects of potassium regulation. Pflugers Arch 2020; 472:1481-1494. [PMID: 32748018 DOI: 10.1007/s00424-020-02410-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 05/24/2020] [Accepted: 05/26/2020] [Indexed: 12/20/2022]
Abstract
In myotonia, reduced Cl- conductance of the mutated ClC-1 channels causes hindered muscle relaxation after forceful voluntary contraction due to muscle membrane hyperexcitability. Repetitive contraction temporarily decreases myotonia, a phenomena called "warm up." The underlying mechanism for the reduction of hyperexcitability in warm-up is currently unknown. Since potassium displacement is known to reduce excitability in, for example, muscle fatigue, we characterized the role of potassium in native myotonia congenita (MC) muscle. Muscle specimens of ADR mice (an animal model for low gCl- conductance myotonia) were exposed to increasing K+ concentrations. To characterize functional effects of potassium ion current, the muscle of ADR mice was exposed to agonists and antagonists of the big conductance Ca2+-activated K+ channel (BK) and the voltage-gated Kv7 channel. Effects were monitored by functional force and membrane potential measurements. By increasing [K+]0 to 5 mM, the warm-up phenomena started earlier and at [K+]0 7 mM only weak myotonia was detected. The increase of [K+]0 caused a sustained membrane depolarization accompanied with a reduction of myotonic bursts in ADR mice. Retigabine, a Kv7.2-Kv7.5 activator, dose-dependently reduced relaxation deficit of ADR myotonic muscle contraction and promoted the warm-up phenomena. In vitro results of this study suggest that increasing potassium conductivity via activation of voltage-gated potassium channels enhanced the warm-up phenomena, thereby offering a potential therapeutic treatment option for myotonia congenita.
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Affiliation(s)
- Kerstin Hoppe
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital Frankfurt, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital of Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany.
| | - Sunisa Chaiklieng
- Division of Neurophysiology in the Center of Rare Diseases, Ulm University, Albert Einstein Allee 23, 89081, Ulm, Germany
- Faculty of Public Health, Khon Kaen University, Muang Khon Kaen, Thailand
| | - Frank Lehmann-Horn
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, University Hospital of Wuerzburg, Oberduerrbacher Str. 6, 97080, Wuerzburg, Germany
| | - Karin Jurkat-Rott
- Universtiy Medical Center Ulm, Division of Experimental Anesthesiology, Albert-Einstein-Allee 23, 89081, Ullm, Germany
| | - Scott Wearing
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059, Australia
- Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Gerog-Brauchle-Ring 60/62, Munich, Germany
| | - Werner Klingler
- Institute of Health and Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, 4059, Australia
- Department of Anesthesiology, Intensive Care Medicine and Pain Therapy, SRH Clinincs, Hohenzollernstraße 40, 72488, Sigmaringen, Germany
- Department of Conservative and Rehabilitation Orthopedics, Faculty of Sport and Health Science, Technical University of Munich, Gerog-Brauchle-Ring 60/62, Munich, Germany
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Morales F, Pusch M. An Up-to-Date Overview of the Complexity of Genotype-Phenotype Relationships in Myotonic Channelopathies. Front Neurol 2020; 10:1404. [PMID: 32010054 PMCID: PMC6978732 DOI: 10.3389/fneur.2019.01404] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 12/23/2019] [Indexed: 12/11/2022] Open
Abstract
Myotonic disorders are inherited neuromuscular diseases divided into dystrophic myotonias and non-dystrophic myotonias (NDM). The latter is a group of dominant or recessive diseases caused by mutations in genes encoding ion channels that participate in the generation and control of the skeletal muscle action potential. Their altered function causes hyperexcitability of the muscle membrane, thereby triggering myotonia, the main sign in NDM. Mutations in the genes encoding voltage-gated Cl− and Na+ channels (respectively, CLCN1 and SCN4A) produce a wide spectrum of phenotypes, which differ in age of onset, affected muscles, severity of myotonia, degree of hypertrophy, and muscle weakness, disease progression, among others. More than 200 CLCN1 and 65 SCN4A mutations have been identified and described, but just about half of them have been functionally characterized, an approach that is likely extremely helpful to contribute to improving the so-far rather poor clinical correlations present in NDM. The observed poor correlations may be due to: (1) the wide spectrum of symptoms and overlapping phenotypes present in both groups (Cl− and Na+ myotonic channelopathies) and (2) both genes present high genotypic variability. On the one hand, several mutations cause a unique and reproducible phenotype in most patients. On the other hand, some mutations can have different inheritance pattern and clinical phenotypes in different families. Conversely, different mutations can be translated into very similar phenotypes. For these reasons, the genotype-phenotype relationships in myotonic channelopathies are considered complex. Although the molecular bases for the clinical variability present in myotonic channelopathies remain obscure, several hypotheses have been put forward to explain the variability, which include: (a) differential allelic expression; (b) trans-acting genetic modifiers; (c) epigenetic, hormonal, or environmental factors; and (d) dominance with low penetrance. Improvements in clinical tests, the recognition of the different phenotypes that result from particular mutations and the understanding of how a mutation affects the structure and function of the ion channel, together with genetic screening, is expected to improve clinical correlation in NDMs.
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Affiliation(s)
- Fernando Morales
- Instituto de Investigaciones en Salud, Universidad de Costa, San José, Costa Rica
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Elia N, Palmio J, Castañeda MS, Shieh PB, Quinonez M, Suominen T, Hanna MG, Männikkö R, Udd B, Cannon SC. Myasthenic congenital myopathy from recessive mutations at a single residue in Na V1.4. Neurology 2019; 92:e1405-e1415. [PMID: 30824560 PMCID: PMC6453767 DOI: 10.1212/wnl.0000000000007185] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 11/04/2018] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE To identify the genetic and physiologic basis for recessive myasthenic congenital myopathy in 2 families, suggestive of a channelopathy involving the sodium channel gene, SCN4A. METHODS A combination of whole exome sequencing and targeted mutation analysis, followed by voltage-clamp studies of mutant sodium channels expressed in fibroblasts (HEK cells) and Xenopus oocytes. RESULTS Missense mutations of the same residue in the skeletal muscle sodium channel, R1460 of NaV1.4, were identified in a family and a single patient of Finnish origin (p.R1460Q) and a proband in the United States (p.R1460W). Congenital hypotonia, breathing difficulties, bulbar weakness, and fatigability had recessive inheritance (homozygous p.R1460W or compound heterozygous p.R1460Q and p.R1059X), whereas carriers were either asymptomatic (p.R1460W) or had myotonia (p.R1460Q). Sodium currents conducted by mutant channels showed unusual mixed defects with both loss-of-function (reduced amplitude, hyperpolarized shift of inactivation) and gain-of-function (slower entry and faster recovery from inactivation) changes. CONCLUSIONS Novel mutations in families with myasthenic congenital myopathy have been identified at p.R1460 of the sodium channel. Recessive inheritance, with experimentally established loss-of-function, is a consistent feature of sodium channel based myasthenia, whereas the mixed gain of function for p.R1460 may also cause susceptibility to myotonia.
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Affiliation(s)
- Nathaniel Elia
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Johanna Palmio
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Marisol Sampedro Castañeda
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Perry B Shieh
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Marbella Quinonez
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Tiina Suominen
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Michael G Hanna
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Roope Männikkö
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Bjarne Udd
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland
| | - Stephen C Cannon
- From the Departments of Physiology (N.E., M.Q., S.C.C.) and Neurology (P.B.S.), David Geffen School of Medicine at UCLA; Molecular and Cellular Integrative Physiology Program at UCLA (N.E., S.C.C.), Los Angeles, CA; Tampere Neuromuscular Center (J.P., T.S., B.U.), Tampere University and University Hospital, Finland; MRC Centre for Neuromuscular Diseases (M.S.C., M.G.H., R.M.), Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK; Folkhälsan Genetic Institute (B.U.), Helsinki; and Neurology Department (B.U.), Vasa Central Hospital, Finland.
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9
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Hoppe K, Chaiklieng S, Lehmann‐Horn F, Jurkat‐Rott K, Wearing S, Klingler W. Elevation of extracellular osmolarity improves signs of myotonia congenita in vitro: a preclinical animal study. J Physiol 2019; 597:225-235. [PMID: 30284249 PMCID: PMC6312412 DOI: 10.1113/jp276528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Accepted: 10/01/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS During myotonia congenita, reduced chloride (Cl- ) conductance results in impaired muscle relaxation and increased muscle stiffness after forceful voluntary contraction. Repetitive contraction of myotonic muscle decreases or even abolishes myotonic muscle stiffness, a phenomenon called 'warm up'. Pharmacological inhibition of low Cl- channels by anthracene-9-carboxylic acid in muscle from mice and ADR ('arrested development of righting response') muscle from mice showed a relaxation deficit under physiological conditions compared to wild-type muscle. At increased osmolarity up to 400 mosmol L-1 , the relaxation deficit of myotonic muscle almost reached that of control muscle. These effects were mediated by the cation and anion cotransporter, NKCC1, and anti-myotonic effects of hypertonicity were at least partly antagonized by the application of bumetanide. ABSTRACT Low chloride-conductance myotonia is caused by mutations in the skeletal muscle chloride (Cl- ) channel gene type 1 (CLCN1). Reduced Cl- conductance of the mutated channels results in impaired muscle relaxation and increased muscle stiffness after forceful voluntary contraction. Exercise decreases muscle stiffness, a phenomena called 'warm up'. To gain further insight into the patho-mechanism of impaired muscle stiffness and the warm-up phenomenon, we characterized the effects of increased osmolarity on myotonic function. Functional force and membrane potential measurements were performed on muscle specimens of ADR ('arrested development of righting response') mice (an animal model for low gCl- conductance myotonia) and pharmacologically-induced myotonia. Specimens were exposed to solutions of increasing osmolarity at the same time as force and membrane potentials were monitored. In the second set of experiments, ADR muscle and pharmacologically-induced myotonic muscle were exposed to an antagonist of NKCC1. Upon osmotic stress, ADR muscle was depolarized to a lesser extent than control wild-type muscle. High osmolarity diminished myotonia and facilitated the warm-up phenomenon as depicted by a faster muscle relaxation time (T90/10 ). Osmotic stress primarily resulted in the activation of the NKCC1. The inhibition of NKCC1 with bumetanide prevented the depolarization and reversed the anti-myotonic effect of high osmolarity. Increased osmolarity decreased signs of myotonia and facilitated the warm-up phenomenon in different in vitro models of myotonia. Activation of NKCC1 activity promotes warm-up and reduces the number of contractions required to achieve normal relaxation kinetics.
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Affiliation(s)
- Kerstin Hoppe
- Department of AnaesthesiaCritical Care Medicine and Pain TherapyUniversity of FrankfurtFrankfurtGermany
| | - Sunisa Chaiklieng
- Division of Neurophysiology in the Center of Rare DiseasesUlm UniversityUlmGermany
- Faculty of Public HealthKhon Knen UniversityMuang Khon KaenThailand
| | - Frank Lehmann‐Horn
- Division of Neurophysiology in the Center of Rare DiseasesUlm UniversityUlmGermany
| | - Karin Jurkat‐Rott
- Department of NeuroanaesthesiologyNeurosurgical UniversityGuenzburgGermany
| | - Scott Wearing
- Institute of Health and Biomedical InnovationQueensland University of TechnologyKelvin GroveQLDAustralia
| | - Werner Klingler
- Institute of Health and Biomedical InnovationQueensland University of TechnologyKelvin GroveQLDAustralia
- Department of NeuroanaesthesiologyNeurosurgical UniversityGuenzburgGermany
- Department of AnaesthesiologyIntensive Care Medicine and Pain TherapySRH KlinikumSigmarringenGermany
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10
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Kuhn ER, Naik AR, Lewis BE, Kokotovich KM, Li M, Stemmler TL, Larsson L, Jena BP. Nanothermometry Reveals Calcium-Induced Remodeling of Myosin. NANO LETTERS 2018; 18:7021-7029. [PMID: 30346792 PMCID: PMC6818504 DOI: 10.1021/acs.nanolett.8b02989] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ions greatly influence protein structure-function and are critical to health and disease. A 10, 000-fold higher calcium in the sarcoplasmic reticulum (SR) of muscle suggests elevated calcium levels near active calcium channels at the SR membrane and the impact of localized high calcium on the structure-function of the motor protein myosin. In the current study, combined quantum dot (QD)-based nanothermometry and circular dichroism (CD) spectroscopy enabled detection of previously unknown enthalpy changes and associated structural remodeling of myosin, impacting its function following exposure to elevated calcium. Cadmium telluride QDs adhere to myosin, function as thermal sensors, and reveal that exposure of myosin to calcium is exothermic, resulting in lowering of enthalpy, a decrease in alpha helical content measured using CD spectroscopy, and the consequent increase in motor efficiency. Isolated muscle fibers subjected to elevated levels of calcium further demonstrate fiber lengthening and decreased motility of actin filaments on myosin-functionalized substrates. Our results, in addition to providing new insights into our understanding of muscle structure-function, establish a novel approach to understand the enthalpy of protein-ion interactions and the accompanying structural changes that may occur within the protein molecule.
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Affiliation(s)
- Eric R. Kuhn
- Department of Physiology, School of Medicine, Wayne State University, Detroit, Michigan 48201, United States
| | - Akshata R. Naik
- Department of Physiology, School of Medicine, Wayne State University, Detroit, Michigan 48201, United States
| | - Brianne E. Lewis
- Department of Pharmaceutical Science, College of Pharmacy, Wayne State University, Detroit, Michigan 48201, United States
| | - Keith M. Kokotovich
- Department of Physiology, School of Medicine, Wayne State University, Detroit, Michigan 48201, United States
| | - Meishan Li
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Timothy L. Stemmler
- Department of Pharmaceutical Science, College of Pharmacy, Wayne State University, Detroit, Michigan 48201, United States
| | - Lars Larsson
- Department of Physiology and Pharmacology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Bhanu P. Jena
- Department of Physiology, School of Medicine, Wayne State University, Detroit, Michigan 48201, United States
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11
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Cannon SC. Skeletal muscle channelopathy: a new risk for sudden infant death syndrome. Lancet 2018; 391:1457-1458. [PMID: 29605428 DOI: 10.1016/s0140-6736(18)30477-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Accepted: 01/17/2018] [Indexed: 11/19/2022]
Affiliation(s)
- Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA.
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12
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Maggi L, Ravaglia S, Farinato A, Brugnoni R, Altamura C, Imbrici P, Camerino DC, Padovani A, Mantegazza R, Bernasconi P, Desaphy JF, Filosto M. Coexistence of CLCN1 and SCN4A mutations in one family suffering from myotonia. Neurogenetics 2017; 18:219-225. [PMID: 28993909 DOI: 10.1007/s10048-017-0525-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 10/01/2017] [Indexed: 01/28/2023]
Abstract
Non-dystrophic myotonias are characterized by clinical overlap making it challenging to establish genotype-phenotype correlations. We report clinical and electrophysiological findings in a girl and her father concomitantly harbouring single heterozygous mutations in SCN4A and CLCN1 genes. Functional characterization of N1297S hNav1.4 mutant was performed by patch clamp. The patients displayed a mild phenotype, mostly resembling a sodium channel myotonia. The CLCN1 c.501C>G (p.F167L) mutation has been already described in recessive pedigrees, whereas the SCN4A c.3890A>G (p.N1297S) variation is novel. Patch clamp experiments showed impairment of fast and slow inactivation of the mutated Nav1.4 sodium channel. The present findings suggest that analysis of both SCN4A and CLCN1 genes should be considered in myotonic patients with atypical clinical and neurophysiological features.
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Affiliation(s)
- Lorenzo Maggi
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy.
| | | | - Alessandro Farinato
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Raffaella Brugnoni
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy
| | - Concetta Altamura
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Paola Imbrici
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Diana Conte Camerino
- Department of Pharmacy and Drug Sciences, University of Bari Aldo Moro, Bari, Italy
| | - Alessandro Padovani
- Center for Neuromuscular Diseases and Neuropathies, Unit of Neurology ASST "Spedali Civili", University of Brescia, Brescia, Italy
| | - Renato Mantegazza
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy
| | - Pia Bernasconi
- Neurology IV - Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133, Milan, Italy
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, University of Bari Aldo Moro, Bari, Italy
| | - Massimiliano Filosto
- Center for Neuromuscular Diseases and Neuropathies, Unit of Neurology ASST "Spedali Civili", University of Brescia, Brescia, Italy
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13
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Hawash AA, Voss AA, Rich MM. Inhibiting persistent inward sodium currents prevents myotonia. Ann Neurol 2017; 82:385-395. [PMID: 28833464 PMCID: PMC5639374 DOI: 10.1002/ana.25017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 07/28/2017] [Accepted: 08/13/2017] [Indexed: 12/20/2022]
Abstract
OBJECTIVE Patients with myotonia congenita have muscle hyperexcitability due to loss-of-function mutations in the ClC-1 chloride channel in skeletal muscle, which causes involuntary firing of muscle action potentials (myotonia), producing muscle stiffness. The excitatory events that trigger myotonic action potentials in the absence of stabilizing ClC-1 current are not fully understood. Our goal was to identify currents that trigger spontaneous firing of muscle in the setting of reduced ClC-1 current. METHODS In vitro intracellular current clamp and voltage clamp recordings were performed in muscle from a mouse model of myotonia congenita. RESULTS Intracellular recordings revealed a slow afterdepolarization (AfD) that triggers myotonic action potentials. The AfD is well explained by a tetrodotoxin-sensitive and voltage-dependent Na+ persistent inward current (NaPIC). Notably, this NaPIC undergoes slow inactivation over seconds, suggesting this may contribute to the end of myotonic runs. Highlighting the significance of this mechanism, we found that ranolazine and elevated serum divalent cations eliminate myotonia by inhibiting AfD and NaPIC. INTERPRETATION This work significantly changes our understanding of the mechanisms triggering myotonia. Our work suggests that the current focus of treating myotonia, blocking the transient Na+ current underlying action potentials, is an inefficient approach. We show that inhibiting NaPIC is paralleled by elimination of myotonia. We suggest the ideal myotonia therapy would selectively block NaPIC and spare the transient Na+ current. Ann Neurol 2017;82:385-395.
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Affiliation(s)
- Ahmed A Hawash
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
| | - Andrew A Voss
- Department of Biology, Wright State University, Dayton, OH
| | - Mark M Rich
- Department of Neuroscience, Cell Biology, and Physiology, Wright State University, Dayton, OH
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14
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Chadda KR, Jeevaratnam K, Lei M, Huang CLH. Sodium channel biophysics, late sodium current and genetic arrhythmic syndromes. Pflugers Arch 2017; 469:629-641. [PMID: 28265756 PMCID: PMC5438422 DOI: 10.1007/s00424-017-1959-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Accepted: 02/14/2017] [Indexed: 12/11/2022]
Abstract
Arrhythmias arise from breakdown of orderly action potential (AP) activation, propagation and recovery driven by interactive opening and closing of successive voltage-gated ion channels, in which one or more Na+ current components play critical parts. Early peak, Na+ currents (INa) reflecting channel activation drive the AP upstroke central to cellular activation and its propagation. Sustained late Na+ currents (INa-L) include contributions from a component with a delayed inactivation timecourse influencing AP duration (APD) and refractoriness, potentially causing pro-arrhythmic phenotypes. The magnitude of INa-L can be analysed through overlaps or otherwise in the overall voltage dependences of the steady-state properties and kinetics of activation and inactivation of the Na+ conductance. This was useful in analysing repetitive firing associated with paramyotonia congenita in skeletal muscle. Similarly, genetic cardiac Na+ channel abnormalities increasing INa-L are implicated in triggering phenomena of automaticity, early and delayed afterdepolarisations and arrhythmic substrate. This review illustrates a wide range of situations that may accentuate INa-L. These include (1) overlaps between steady-state activation and inactivation increasing window current, (2) kinetic deficiencies in Na+ channel inactivation leading to bursting phenomena associated with repetitive channel openings and (3) non-equilibrium gating processes causing channel re-opening due to more rapid recoveries from inactivation. All these biophysical possibilities were identified in a selection of abnormal human SCN5A genotypes. The latter presented as a broad range of clinical arrhythmic phenotypes, for which effective therapeutic intervention would require specific identification and targeting of the diverse electrophysiological abnormalities underlying their increased INa-L.
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Affiliation(s)
- Karan R Chadda
- Faculty of Health and Medical Sciences, University of Surrey, VSM Building, Guildford, GU2 7AL, UK
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK
| | - Kamalan Jeevaratnam
- Faculty of Health and Medical Sciences, University of Surrey, VSM Building, Guildford, GU2 7AL, UK
- School of Medicine, Perdana University-Royal College of Surgeons Ireland, 43400, Serdang, Selangor Darul Ehsan, Malaysia
| | - Ming Lei
- Department of Pharmacology, University of Oxford, Oxford, OX1 3QT, UK
| | - Christopher L-H Huang
- Physiological Laboratory, University of Cambridge, Downing Street, Cambridge, CB2 3EG, UK.
- Department of Biochemistry, University of Cambridge, Hopkins Building, Cambridge, CB2 1QW, UK.
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15
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Skov M, de Paoli FV, Nielsen OB, Pedersen TH. The anti-convulsants lacosamide, lamotrigine, and rufinamide reduce myotonia in isolated human and rat skeletal muscle. Muscle Nerve 2017; 56:136-142. [PMID: 27783415 DOI: 10.1002/mus.25452] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 10/14/2016] [Accepted: 10/19/2016] [Indexed: 11/11/2022]
Abstract
INTRODUCTION In myotonia congenita, loss of ClC-1 Cl- channel function results in skeletal muscle hyperexcitability and myotonia. Anti-myotonic treatment has typically targeted the voltage-gated sodium channel in skeletal muscle (Nav1.4). In this study we explored whether 3 sodium channel-modulating anti-epileptics can reduce myotonia in isolated rat and human muscle. METHODS Dissected muscles were rendered myotonic by ClC-1 channel inhibition. The ability of the drugs to suppress myotonia was then assessed from subclinical to maximal clinical concentrations. Drug synergy was determined using isobole plots. RESULTS All drugs were capable of abolishing myotonia in both rat and human muscles. Lamotrigine and rufinamide completely suppressed myotonia at submaximal clinical concentrations, whereas lacosamide had to be raised above the maximal clinical concentration to suppress myotonia completely. A synergistic effect of lamotrigine and rufinamide was observed. CONCLUSION These findings suggest that lamotrigine and rufinamide could be considered for anti-myotonic treatment in myotonia congenita. Muscle Nerve 56: 136-142, 2017.
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Affiliation(s)
- Martin Skov
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark
| | - Frank V de Paoli
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark.,Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital Skejby, Aarhus, Denmark
| | - Ole B Nielsen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark
| | - Thomas H Pedersen
- Department of Biomedicine, Aarhus University, Ole Worms Allé 4, 8000, Aarhus C, Denmark
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16
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Desaphy JF, Carbonara R, D'Amico A, Modoni A, Roussel J, Imbrici P, Pagliarani S, Lucchiari S, Lo Monaco M, Conte Camerino D. Translational approach to address therapy in myotonia permanens due to a new SCN4A mutation. Neurology 2016; 86:2100-8. [PMID: 27164696 PMCID: PMC4891212 DOI: 10.1212/wnl.0000000000002721] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Accepted: 02/19/2016] [Indexed: 01/26/2023] Open
Abstract
Objective: We performed a clinical, functional, and pharmacologic characterization of the novel p.P1158L Nav1.4 mutation identified in a young girl presenting a severe myotonic phenotype. Methods: Wild-type hNav1.4 channel and P1158L mutant were expressed in tsA201 cells for functional and pharmacologic studies using patch-clamp. Results: The patient shows pronounced myotonia, slowness of movements, and generalized muscle hypertrophy. Because of general discomfort with mexiletine, she was given flecainide with satisfactory response. In vitro, mutant channels show a slower current decay and a rightward shift of the voltage dependence of fast inactivation. The voltage dependence of activation and slow inactivation were not altered. Mutant channels were less sensitive to mexiletine, whereas sensitivity to flecainide was not altered. The reduced inhibition of mutant channels by mexiletine was also observed using clinically relevant drug concentrations in a myotonic-like condition. Conclusions: Clinical phenotype and functional alterations of P1158L support the diagnosis of myotonia permanens. Impairment of fast inactivation is consistent with the possible role of the channel domain III S4-S5 loop in the inactivation gate docking site. The reduced sensitivity of P1158L to mexiletine may have contributed to the unsatisfactory response of the patient. The success of flecainide therapy underscores the usefulness of in vitro functional studies to help in the choice of the best drug for each individual.
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Affiliation(s)
- Jean-François Desaphy
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy.
| | - Roberta Carbonara
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Adele D'Amico
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Anna Modoni
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Julien Roussel
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Paola Imbrici
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Serena Pagliarani
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Sabrina Lucchiari
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Mauro Lo Monaco
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
| | - Diana Conte Camerino
- From the Departments of Biomedical Sciences and Human Oncology (J.-F.D.) and Pharmacy & Drug Sciences (R.C., J.R., P.I., D.C.C.), University of Bari Aldo Moro, Bari; Unit of Neuromuscular and Neurodegenerative Disorders (A.D.), Bambino Gesù Children's Hospital, Rome; Departments of Geriatrics, Neurosciences, and Orthopedics (A.M., M.L.M.), Institute of Neurology, Catholic University of the Sacred Heart, Rome; Dino Ferrari Centre (S.P., S.L.), Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan; and Neurology Unit (S.P., S.L.), IRCCS Foundation Ca' Granda, Ospedale Maggiore Policlinico, Milan, Italy
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Abstract
Familial disorders of skeletal muscle excitability were initially described early in the last century and are now known to be caused by mutations of voltage-gated ion channels. The clinical manifestations are often striking, with an inability to relax after voluntary contraction (myotonia) or transient attacks of severe weakness (periodic paralysis). An essential feature of these disorders is fluctuation of symptoms that are strongly impacted by environmental triggers such as exercise, temperature, or serum K(+) levels. These phenomena have intrigued physiologists for decades, and in the past 25 years the molecular lesions underlying these disorders have been identified and mechanistic studies are providing insights for therapeutic strategies of disease modification. These familial disorders of muscle fiber excitability are "channelopathies" caused by mutations of a chloride channel (ClC-1), sodium channel (NaV1.4), calcium channel (CaV1.1), and several potassium channels (Kir2.1, Kir2.6, and Kir3.4). This review provides a synthesis of the mechanistic connections between functional defects of mutant ion channels, their impact on muscle excitability, how these changes cause clinical phenotypes, and approaches toward therapeutics.
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Affiliation(s)
- Stephen C Cannon
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
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18
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Mankodi A, Grunseich C, Skov M, Cook L, Aue G, Purev E, Bakar D, Lehky T, Jurkat-Rott K, Pedersen TH, Childs RW. Divalent cation-responsive myotonia and muscle paralysis in skeletal muscle sodium channelopathy. Neuromuscul Disord 2015; 25:908-12. [PMID: 26494408 DOI: 10.1016/j.nmd.2015.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/11/2015] [Accepted: 08/14/2015] [Indexed: 10/23/2022]
Abstract
We report a patient with paramyotonia congenita/hyperkalemic periodic paralysis due to Nav1.4 I693T mutation who had worsening of myotonia and muscle weakness in the setting of hypomagnesemia and hypocalcemia with marked recovery after magnesium administration. Computer simulations of the effects of the I693T mutation were introduced in the muscle fiber model by both hyperpolarizing shifts in the Nav1.4 channel activation and a faster recovery from slow channel inactivation. A further shift in the Nav1.4 channel activation in the hyperpolarizing direction as expected with low divalent cations resulted in myotonia that progressed to membrane inexcitability. Shifting the channel activation in the depolarizing direction as would be anticipated from magnesium supplementation abolished the myotonia. These observations provide clinical and biophysical evidence that the muscle symptoms in sodium channelopathy are sensitive to divalent cations. Exploration of the role of magnesium administration in therapy or prophylaxis is warranted with a randomized clinical trial.
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Affiliation(s)
- Ami Mankodi
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA.
| | - Christopher Grunseich
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Martin Skov
- Department of Biomedicine, University of Aarhus, 8000 Aarhus, Denmark
| | - Lisa Cook
- Section of Transplantation Immunotherapy, National Heart, Lung, and Blood Institute, Bethesda, MD 20892, USA
| | - Georg Aue
- Section of Transplantation Immunotherapy, National Heart, Lung, and Blood Institute, Bethesda, MD 20892, USA
| | - Enkhtsetseg Purev
- Section of Transplantation Immunotherapy, National Heart, Lung, and Blood Institute, Bethesda, MD 20892, USA
| | - Dara Bakar
- Neurogenetics Branch, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Tanya Lehky
- Clinical Neurophysiology Program, EMG Section, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | | | - Thomas H Pedersen
- Department of Biomedicine, University of Aarhus, 8000 Aarhus, Denmark
| | - Richard W Childs
- Section of Transplantation Immunotherapy, National Heart, Lung, and Blood Institute, Bethesda, MD 20892, USA
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Imbrici P, Altamura C, Pessia M, Mantegazza R, Desaphy JF, Camerino DC. ClC-1 chloride channels: state-of-the-art research and future challenges. Front Cell Neurosci 2015; 9:156. [PMID: 25964741 PMCID: PMC4410605 DOI: 10.3389/fncel.2015.00156] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Accepted: 04/08/2015] [Indexed: 01/06/2023] Open
Abstract
The voltage-dependent ClC-1 chloride channel belongs to the CLC channel/transporter family. It is a homodimer comprising two individual pores which can operate independently or simultaneously according to two gating modes, the fast and the slow gate of the channel. ClC-1 is preferentially expressed in the skeletal muscle fibers where the presence of an efficient Cl(-) homeostasis is crucial for the correct membrane repolarization and propagation of action potential. As a consequence, mutations in the CLCN1 gene cause dominant and recessive forms of myotonia congenita (MC), a rare skeletal muscle channelopathy caused by abnormal membrane excitation, and clinically characterized by muscle stiffness and various degrees of transitory weakness. Elucidation of the mechanistic link between the genetic defects and the disease pathogenesis is still incomplete and, at this time, there is no specific treatment for MC. Still controversial is the subcellular localization pattern of ClC-1 channels in skeletal muscle as well as its modulation by some intracellular factors. The expression of ClC-1 in other tissues such as in brain and heart and the possible assembly of ClC-1/ClC-2 heterodimers further expand the physiological properties of ClC-1 and its involvement in diseases. A recent de novo CLCN1 truncation mutation in a patient with generalized epilepsy indeed postulates an unexpected role of this channel in the control of neuronal network excitability. This review summarizes the most relevant and state-of-the-art research on ClC-1 chloride channels physiology and associated diseases.
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Affiliation(s)
- Paola Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Concetta Altamura
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Mauro Pessia
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | - Renato Mantegazza
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
| | | | - Diana Conte Camerino
- Department of Pharmacy - Drug Sciences, University of Bari “Aldo Moro”,Bari, Italy
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Skov M, De Paoli FV, Lausten J, Nielsen OB, Pedersen TH. Extracellular magnesium and calcium reduce myotonia in isolated ClC-1 chloride channel-inhibited human muscle. Muscle Nerve 2014; 51:65-71. [PMID: 24710922 DOI: 10.1002/mus.24260] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/02/2014] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Experimental myotonia induced in rat muscle by ClC-1 chloride channel-inhibited has been shown to be related inversely to extracellular concentrations of Mg(2+) and Ca(2+) ([Mg(2+) ]o and [Ca(2+) ]o) within physiological ranges. Because this implicates a role for [Mg(2+)]o and [Ca(2+)]o in the variability of symptoms among myotonia congenita patients, we searched for similar effects of [Mg(2+)]o and [Ca(2+)]o on myotonia in human muscle. METHODS Bundles of muscle fibers were isolated from abdominal rectus in patients undergoing abdominal surgery. Myotonia was induced by ClC-1 inhibition using 9-anthracene carboxylic acid (9-AC) and was assessed from integrals of force induced by 5-Hz stimulation for 2 seconds. RESULTS Myotonia disappeared gradually when [Mg(2+)]o or [Ca(2+)]o were elevated throughout their physiological ranges. These effects of [Mg(2+)]o and [Ca(2+)]o were additive and interchangeable. CONCLUSIONS These findings suggest that variations in symptoms in myotonia congenita patients may arise from physiological variations in serum Mg(2+) and Ca(2+).
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Affiliation(s)
- Martin Skov
- Department of Biomedicine, Aarhus University, Aarhus, Denmark, Ole Worms Allé 4, 8000, Aarhus C, Denmark
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Heterozygous CLCN1 mutations can modulate phenotype in sodium channel myotonia. Neuromuscul Disord 2014; 24:953-9. [PMID: 25088311 DOI: 10.1016/j.nmd.2014.06.439] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Revised: 06/17/2014] [Accepted: 06/23/2014] [Indexed: 11/23/2022]
Abstract
Nondystrophic myotonias are characterized by muscle stiffness triggered by voluntary movement. They are caused by mutations in either the CLCN1 gene in myotonia congenita or in the SCN4A gene in paramyotonia congenita and sodium channel myotonias. Clinical and electrophysiological phenotypes of these disorders have been well described. No concomitant mutations in both genes have been reported yet. We report five patients from three families showing myotonia with both chloride and sodium channel mutations. Their clinical and electrophysiological phenotypes did not fit with the phenotype known to be associated with the mutation initially found in SCN4A gene, which led us to screen and find an additional mutation in CLCN1 gene. Our electrophysiological and clinical observations suggest that heterozygous CLCN1 mutations can modify the clinical and electrophysiological expression of SCN4A mutation.
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