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Kokunai Y, Dalle C, Vicart S, Sternberg D, Pouliot V, Bendahhou S, Fournier E, Chahine M, Fontaine B, Nicole S. A204E mutation in Na v1.4 DIS3 exerts gain- and loss-of-function effects that lead to periodic paralysis combining hyper- with hypo-kalaemic signs. Sci Rep 2018; 8:16681. [PMID: 30420713 PMCID: PMC6232142 DOI: 10.1038/s41598-018-34750-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Accepted: 10/25/2018] [Indexed: 12/11/2022] Open
Abstract
Periodic paralyses (PP) are characterized by episodic muscle weakness and are classified into the distinct hyperkalaemic (hyperPP) and hypokalaemic (hypoPP) forms. The dominantly-inherited form of hyperPP is caused by overactivity of Nav1.4 - the skeletal muscle voltage-gated sodium channel. Familial hypoPP results from a leaking gating pore current induced by dominant mutations in Nav1.4 or Cav1.1, the skeletal muscle voltage-gated calcium channel. Here, we report an individual with clinical signs of hyperPP and hypokalaemic episodes of muscle paralysis who was heterozygous for the novel p.Ala204Glu (A204E) substitution located in one region of Nav1.4 poor in disease-related variations. A204E induced a significant decrease of sodium current density, increased the window current, enhanced fast and slow inactivation of Nav1.4, and did not cause gating pore current in functional analyses. Interestingly, the negative impact of A204E on Nav1.4 activation was strengthened in low concentration of extracellular K+. Our data prove the existence of a phenotype combining signs of hyperPP and hypoPP due to dominant Nav1.4 mutations. The hyperPP component would result from gain-of-function effects on Nav1.4 and the hypokalemic episodes of paralysis from loss-of-function effects strengthened by low K+. Our data argue for a non-negligible role of Nav1.4 loss-of-function in familial hypoPP.
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Affiliation(s)
- Yosuke Kokunai
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Carine Dalle
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
| | - Savine Vicart
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Damien Sternberg
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Valérie Pouliot
- Centre de recherche CERVO, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, G1J 2G3, Canada
- Department of Medicine, Université Laval, Quebec City, QC, G1K 7P4, Canada
| | - Said Bendahhou
- CNRS UMR7370, LP2M, Labex ICST, University Nice Sophia-Antipolis, Faculté de Médecine, Nice, France
| | - Emmanuel Fournier
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France
| | - Mohamed Chahine
- Centre de recherche CERVO, Institut Universitaire en Santé Mentale de Québec, Quebec City, QC, G1J 2G3, Canada
- Department of Medicine, Université Laval, Quebec City, QC, G1K 7P4, Canada
| | - Bertrand Fontaine
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France.
- AP-HP, Hôpital Universitaire Pitié-Salpétrière, National Reference Center for Channelopathies, F-75013, Paris, France.
| | - Sophie Nicole
- Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM), F-75013, Paris, France.
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Cavalli M, Fossati B, Vitale R, Brigonzi E, Ricigliano VAG, Saraceno L, Cardani R, Pappone C, Meola G. Flecainide-Induced Brugada Syndrome in a Patient With Skeletal Muscle Sodium Channelopathy: A Case Report With Critical Therapeutical Implications and Review of the Literature. Front Neurol 2018; 9:385. [PMID: 29899727 PMCID: PMC5988887 DOI: 10.3389/fneur.2018.00385] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/11/2018] [Indexed: 12/31/2022] Open
Abstract
Skeletal muscle sodium channelopathies are a group of neuromuscular disorders associated with mutations in the SCN4A gene. Because principal sodium channel isoforms expressed in the skeletal muscles and the heart are distinct one from the other, this condition usually spares cardiac functioning. Nonetheless, evidence on a possible link between skeletal muscle and cardiac sodium channelopathies has emerged in recent years. To date, eight patients bearing pathogenetic mutations in the SCN4A gene and manifesting cardiac electrophysiological alterations have been reported in literature. Among these patients, three presented a phenotype compatible with Brugada syndrome. We report the case of a 29-year-old patient affected by non-dystrophic myotonia associated with a p.G1306E mutation in the SCN4A gene, who presented symptoms of syncope and palpitation after the introduction of flecainide as an anti-myotonic agent. ECG and ajmaline challenge were consistent with the diagnosis of Brugada syndrome, leading to the implantation of a cardioverter defibrillator. No mutation in causative genes for Brugada syndrome was detected. Mexiletine treatment reduced myotonia without any cardiac adverse events. This case report highlights the clinical relevance of the recognition of cardiac electrophysiological alterations in skeletal muscle sodium channelopathies. The discovery of a possible pathogenetic linkage between skeletal muscle and cardiac sodium channelopathies may have significant implications in patients' management, also in light of the fact that class 1C anti-arrhythmics are potential triggers for life-threatening arrhythmias in patients with Brugada syndrome.
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Affiliation(s)
- Michele Cavalli
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Barbara Fossati
- Department of Neurology, IRCCS Policlinico San Donato, Milan, Italy
| | - Raffaele Vitale
- Clinical Arrhythmology and Electrophysiology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Elisa Brigonzi
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Vito A G Ricigliano
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Lorenzo Saraceno
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Rosanna Cardani
- Laboratory of Muscle Histopathology and Molecular Biology, IRCCS Policlinico San Donato, Milan, Italy
| | - Carlo Pappone
- Clinical Arrhythmology and Electrophysiology Department, IRCCS Policlinico San Donato, Milan, Italy
| | - Giovanni Meola
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy.,Department of Neurology, IRCCS Policlinico San Donato, Milan, Italy
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Abstract
Voltage-gated sodium channels are present in different tissues within the human body, predominantly nerve, muscle, and heart. The sodium channel is composed of four similar domains, each containing six transmembrane segments. Each domain can be functionally organized into a voltage-sensing region and a pore region. The sodium channel may exist in resting, activated, fast inactivated, or slow inactivated states. Upon depolarization, when the channel opens, the fast inactivation gate is in its open state. Within the time frame of milliseconds, this gate closes and blocks the channel pore from conducting any more sodium ions. Repetitive or continuous stimulations of sodium channels result in a rate-dependent decrease of sodium current. This process may continue until the channel fully shuts down. This collapse is known as slow inactivation. This chapter reviews what is known to date regarding, sodium channel inactivation with a focus on various mutations within each NaV subtype and with clinical implications.
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Affiliation(s)
- M-R Ghovanloo
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - K Aimar
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - R Ghadiry-Tavi
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - A Yu
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
| | - P C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, BC, Canada
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Abstract
Five inherited human disorders affecting skeletal muscle contraction have been traced to mutations in the gene encoding the voltage-gated sodium channel Nav1.4. The main symptoms of these disorders are myotonia or periodic paralysis caused by changes in skeletal muscle fiber excitability. Symptoms of these disorders vary from mild or latent disease to incapacitating or even death in severe cases. As new human sodium channel mutations corresponding to disease states become discovered, the importance of understanding the role of the sodium channel in skeletal muscle function and disease state grows.
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Affiliation(s)
- Dina Simkin
- UMR 6097, CNRS, TIANP, University of Nice Sophia-Antipolis Nice, France
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Groome JR, Alexander HM, Fujimoto E, Sherry M, Petty D. Central Charged Residues in DIIIS4 Regulate Deactivation Gating in Skeletal Muscle Sodium Channels. Cell Mol Neurobiol 2006; 27:87-106. [PMID: 17151947 DOI: 10.1007/s10571-006-9120-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2006] [Accepted: 09/11/2006] [Indexed: 10/23/2022]
Abstract
1. Mutations in the S4 segment of domain III in the voltage gated skeletal muscle sodium channel hNa(V)1.4 were constructed to test the roles of each charged residue in deactivation gating. Mutations comprised charge reversals at K1-R6, charge neutralization, and substitution at R4 and R5. 2. Charge-reversing mutations at R4 and R5 produced the greatest alteration of activation parameters compared to hNa(V)1.4. Effects included depolarization of the conductance/voltage (g/V) curve, decreased valence and slowing of kinetics. 3. Reversal of charge at R2 to R4 hyperpolarized, and reversal at R5 or R6 depolarized the h (infinity) curve. Most DIIIS4 mutations slowed inactivation from the open state. R4E slowed closed state fast inactivation and R5E inhibited its completion .4. Deactivation from the open and/or inactivated state was prolonged in mutations reversing charge at R2 to R4 but accelerated by reversal of charge at R5 or R6. Effects were most pronounced at central charges R4 and R5. 5. Charge and structure each contribute to effects of mutations at R4 and R5 on channel gating. Effects of mutations on activation and deactivation at R4 and, to a lesser extent R5, were primarily owing to charge alteration, whereas effects on fast inactivation were charge independent.
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Affiliation(s)
- James R Groome
- Department of Biological Sciences, Idaho State University, Pocatello, ID 83204, USA.
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