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Stee K, Van Poucke M, Peelman L, Lowrie M. Paradoxical pseudomyotonia in English Springer and Cocker Spaniels. J Vet Intern Med 2019; 34:253-257. [PMID: 31729100 PMCID: PMC6979413 DOI: 10.1111/jvim.15660] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 10/28/2019] [Indexed: 12/30/2022] Open
Abstract
Background Paramyotonia congenita and Brody disease are well‐described conditions in humans, characterized by exercise‐induced myotonic‐like muscle stiffness. A syndrome similar to Brody disease has been reported in cattle. Reports of a similar syndrome in dogs are scarce. Objectives To define and describe the clinical, diagnostic, and genetic features and disease course of paradoxical pseudomyotonia in Spaniel dogs. Animals Seven client‐owned dogs (4 English Springer Spaniels and 3 English Cocker Spaniels) with clinically confirmed episodes of exercise‐induced generalized myotonic‐like muscle stiffness. Methods Sequential case study. Results All dogs were <24 months of age at onset. The episodes of myotonic‐like generalized muscle stiffness always occurred with exercise, and spontaneously resolved with rest in <45 seconds in all but 1 dog. Extreme outside temperatures seemed to considerably worsen episode frequency and severity in most dogs. Complete blood count, serum biochemistry including electrolytes, urinalysis, brain magnetic resonance imaging, cerebrospinal fluid analysis, electromyography, motor nerve conduction velocity, ECG, and echocardiography were unremarkable. Muscle biopsy samples showed moderate but nonspecific muscle atrophy. The episodes seemed to remain stable or decrease in severity and frequency in 6/7 dogs, and often could be decreased or prevented by avoiding the episode triggers. The underlying genetic cause is not identified yet, because no disease‐causing variants could be found in the coding sequence or splice sites of the 2 major candidate genes, SCN4A and ATP2A1. Conclusions and Clinical Importance Paradoxical pseudomyotonia is a disease affecting Spaniels. It is of variable severity but benign in most cases.
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Affiliation(s)
| | - Mario Van Poucke
- Department of Nutrition, Genetics and Ethology, Ghent University, Merelbeke, Belgium
| | - Luc Peelman
- Department of Nutrition, Genetics and Ethology, Ghent University, Merelbeke, Belgium
| | - Mark Lowrie
- Dovecote Veterinary Hospital, Derby, United Kingdom
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A role for cannabinoids in the treatment of myotonia? Report of compassionate use in a small cohort of patients. J Neurol 2019; 267:415-421. [DOI: 10.1007/s00415-019-09593-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 09/09/2019] [Accepted: 10/18/2019] [Indexed: 12/17/2022]
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53
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Nojszewska M, Lusakowska A, Gawel M, Sierdzinski J, Sulek A, Krysa W, Elert-Dobkowska E, Seroka A, Kaminska AM, Kostera-Pruszczyk A. The needle EMG findings in myotonia congenita. J Electromyogr Kinesiol 2019; 49:102362. [PMID: 31610484 DOI: 10.1016/j.jelekin.2019.102362] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Revised: 09/25/2019] [Accepted: 10/01/2019] [Indexed: 10/25/2022] Open
Abstract
INTRODUCTION Myotonia congenita (MC) is caused by pathogenic variants in the CLCN1 gene coding the chloride channel protein. METHODS To test the hypothesis that needle EMG could be helpful in distinguishing between the recessive and dominant MC, we performed EMG examination in 36 patients (23 men) aged 4-61 years with genetically proven MC: in 30 patients with autosomal recessive MC (Becker MC) and in 6 with autosomal dominant MC (Thomsen MC). RESULTS Myotonic discharges were recorded in 95.8% of examined muscles. For the whole MC group we observed a significant positive correlation between parameters of motor unit activity potentials (MUAPs) in vastus lateralis and tibialis anterior muscles and the duration of the disease. Similar correlation for biceps brachii also was found in Becker MC subgroup only. DISCUSSION EMG could still be helpful in diagnosis of MC and together with provocative tests might be useful in differentiation between recessive and autosomal MC.
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Affiliation(s)
- Monika Nojszewska
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Anna Lusakowska
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Malgorzata Gawel
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Janusz Sierdzinski
- Department of Medical Informatics and Telemedicine, Medical University of Warsaw, Poland.
| | - Anna Sulek
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | - Wioletta Krysa
- Department of Genetics, Institute of Psychiatry and Neurology, Warsaw, Poland
| | | | - Andrzej Seroka
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
| | - Anna M Kaminska
- Department of Neurology, Medical University of Warsaw, Warsaw, Poland
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Wei Z, Huaxing M, Xiaomei W, Juan W, Xueli C, Jing Z, Junhong G. Identification of two novel compound heterozygous CLCN1 mutations associated with autosomal recessive myotonia congenita. Neurol Res 2019; 41:1069-1074. [PMID: 31566103 DOI: 10.1080/01616412.2019.1672392] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Objectives: Myotonia congenita (MC) is a rare genetic muscular disorder caused by CLCN1 mutations, which codes for skeletal muscle chloride channel CLC1. MC is characterized by impaired muscle relaxation after contraction resulting in muscle stiffness. This study aimed to identify the genetic etiology of a Chinese family affected with recessive MC. Methods: Whole exome sequencing was performed to identify the disease-associated variants. The candidate causal genes discovered by WES were then confirmed by Sanger sequencing and co-segregation analyses were also conducted. Results: Two novel compound heterozygous mutations in CLCN1 gene, p.D94Y (paternal allele) and p.Y206* (maternal allele), were successfully identified as the pathogenic mutations by whole-exome sequencing (WES). The mutations were confirmed with Sanger sequencing in the family members and cosegregated with the MC phenotype. The two mutations have not been reported in the HGMD, dbSNP, 1000 Genomes project, ClinVar database, ExAC, and gnomAD previously. Mutation p.D94Y is predicted to be deleterious by using in silico tools and p.Y206* is a nonsense mutation, causing protein synthesis termination. Conclusions: Molecular genetics analysis offers an accurate method for diagnosing MC. Our results expand the mutational spectrum of recessive MC.
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Affiliation(s)
- Zhang Wei
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Meng Huaxing
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Wang Xiaomei
- Department of Geological Engineering, Shanxi Institute of Enegy , Taiyuan , China
| | - Wang Juan
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Chang Xueli
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Zhang Jing
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
| | - Guo Junhong
- Department of Neurology, First Hospital, Shanxi Medical University , Taiyuan , China
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55
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Arbustini E, Di Toro A, Giuliani L, Favalli V, Narula N, Grasso M. Cardiac Phenotypes in Hereditary Muscle Disorders: JACC State-of-the-Art Review. J Am Coll Cardiol 2019; 72:2485-2506. [PMID: 30442292 DOI: 10.1016/j.jacc.2018.08.2182] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/20/2018] [Accepted: 08/10/2018] [Indexed: 01/05/2023]
Abstract
Hereditary muscular diseases commonly involve the heart. Cardiac manifestations encompass a spectrum of phenotypes, including both cardiomyopathies and rhythm disorders. Common biomarkers suggesting cardiomuscular diseases include increased circulating creatine kinase and/or lactic acid levels or disease-specific metabolic indicators. Cardiac and extra-cardiac traits, imaging tests, family studies, and genetic testing provide precise diagnoses. Cardiac phenotypes are mainly dilated and hypokinetic in dystrophinopathies, Emery-Dreifuss muscular dystrophies, and limb girdle muscular dystrophies; hypertrophic in Friedreich ataxia, mitochondrial diseases, glycogen storage diseases, and fatty acid oxidation disorders; and restrictive in myofibrillar myopathies. Left ventricular noncompaction is variably associated with the different myopathies. Conduction defects and arrhythmias constitute a major phenotype in myotonic dystrophies and skeletal muscle channelopathies. Although the actual cardiac management is rarely based on the cause, the cardiac phenotypes need precise characterization because they are often the only or the predominant manifestations and the prognostic determinants of many hereditary muscle disorders.
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Affiliation(s)
- Eloisa Arbustini
- Centre for Inherited Cardiovascular Diseases, IRCCS Foundation, University Hospital Policlinico San Matteo, Pavia, Italy.
| | - Alessandro Di Toro
- Centre for Inherited Cardiovascular Diseases, IRCCS Foundation, University Hospital Policlinico San Matteo, Pavia, Italy
| | - Lorenzo Giuliani
- Centre for Inherited Cardiovascular Diseases, IRCCS Foundation, University Hospital Policlinico San Matteo, Pavia, Italy
| | | | - Nupoor Narula
- Centre for Inherited Cardiovascular Diseases, IRCCS Foundation, University Hospital Policlinico San Matteo, Pavia, Italy; Division of Cardiology, Department of Medicine, New York Presbyterian Hospital, Weill Cornell Medicine, New York, New York
| | - Maurizia Grasso
- Centre for Inherited Cardiovascular Diseases, IRCCS Foundation, University Hospital Policlinico San Matteo, Pavia, Italy
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Elevated Cardiac Troponin T in Patients With Skeletal Myopathies. J Am Coll Cardiol 2019; 71:1540-1549. [PMID: 29622161 DOI: 10.1016/j.jacc.2018.01.070] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/09/2018] [Accepted: 01/26/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Cardiac troponins are often elevated in patients with skeletal muscle disease who have no evidence of cardiac disease. OBJECTIVES The goal of this study was to characterize cardiac troponin concentrations in patients with myopathies and derive insights regarding the source of elevated troponin T measurements. METHODS Cardiac troponin T (cTnT) and cardiac troponin I (cTnI) concentrations were determined by using high sensitivity assays in 74 patients with hereditary and acquired skeletal myopathies. Patients underwent comprehensive cardiac evaluation, including 12-lead electrocardiogram, 24-h electrocardiogram, cardiac magnetic resonance imaging, and coronary artery computed tomography. cTnT and cTnI protein expression was determined in skeletal muscle samples of 9 patients and in control tissues derived from autopsy using antibodies that are used in commercial assays. Relevant Western blot bands were subjected to liquid chromatography tandem mass spectrometry for protein identification. RESULTS Levels of cTnT (median: 24 ng/l; interquartile range: 11 to 54 ng/l) were elevated (>14 ng/l) in 68.9% of patients; cTnI was elevated (>26 ng/l) in 4.1% of patients. Serum cTnT levels significantly correlated with creatine kinase and myoglobin (r = 0.679 and 0.786, respectively; both p < 0.001). Based on cTnT serial testing, 30.1% would have fulfilled current rule-in criteria for myocardial infarction. Noncoronary cardiac disease was present in 23%. Using cTnT antibodies, positive bands were found in both diseased and healthy skeletal muscle at molecular weights approximately 5 kDa below cTnT. Liquid chromatography tandem mass spectrometry identified the presence of skeletal troponin T isoforms in these bands. CONCLUSIONS Measured cTnT concentrations were chronically elevated in the majority of patients with skeletal myopathies, whereas cTnI elevation was rare. Our data indicate that cross-reaction of the cTnT immunoassay with skeletal muscle troponin isoforms was the likely cause.
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Hata T, Nagasaka T, Koh K, Tsuchiya M, Ichinose Y, Nan H, Shindo K, Takiyama Y. Pathological findings in a patient with non-dystrophic myotonia with a mutation of the SCN4A gene; a case report. BMC Neurol 2019; 19:125. [PMID: 31189464 PMCID: PMC6560775 DOI: 10.1186/s12883-019-1360-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 06/06/2019] [Indexed: 12/12/2022] Open
Abstract
Background Non-dystrophic myotonias (NDMs) are skeletal muscle disorders involving myotonia distinct from myotonic dystrophy. It has been reported that the muscle pathology is usually normal or comprises mild myopathic changes in NDMs. We describe various pathological findings mimicking those of myotonic dystrophy (DM) in biopsied muscle specimens from a patient with NDMs with a long disease duration. Case presentation A 66-year-old Japanease man presented eye closure myotonia, percussion myotonia and grip myotonia together with the warm-up phenomenon and cold aggravation from early childhood. On genetic analysis, a heterozygous mutation of the SCN4A gene (c.2065 C > T, p.L689F), with no mutation of the CLCN1, DMPK, or ZNF9/CNBP gene, was detected. He was diagnosed as having NDMs. A biopsy of the biceps brachii muscle showed increasing fiber size variation, internal nuclei, chained nuclei, necrotic fibers, fiber splitting, endomysial fibrosis, pyknotic nuclear clumps and disorganized intermyofibrillar networks. Sarcoplasmic masses, tubular aggregates and ragged-red fibers were absent. Conclusion It is noteworthy that the present study revealed various pathological findings resembling those seen in DM, although the pathology is usually normal or mild in NDMs. The pathological similarities may be due to muscular modification with long-standing myotonia or excessive muscle contraction based on abnormal channel activity. Electronic supplementary material The online version of this article (10.1186/s12883-019-1360-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Takanori Hata
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan
| | - Takamura Nagasaka
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan.
| | - Kishin Koh
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan
| | - Mai Tsuchiya
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan
| | - Yuta Ichinose
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan
| | - Haitian Nan
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan
| | - Kazumasa Shindo
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan
| | - Yoshihisa Takiyama
- Department of Neurology, Faculty of Medicine, University of Yamanashi, 1110, Shimokato, Chuou-city, Yamanashi, 409-3898, Japan
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Vita G, Vita GL, Musumeci O, Rodolico C, Messina S. Genetic neuromuscular disorders: living the era of a therapeutic revolution. Part 2: diseases of motor neuron and skeletal muscle. Neurol Sci 2019; 40:671-681. [PMID: 30805745 DOI: 10.1007/s10072-019-03764-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 02/13/2019] [Indexed: 12/22/2022]
Abstract
This is the second part of a two-part document intended to discuss recent therapeutic progresses in genetic neuromuscular disorders. The present review is for diseases of motor neuron and skeletal muscle, some of which reached recently the most innovative therapeutic approaches. Nusinersen, an SMN2 mRNA splicing modifier, was approved as first-ever therapy of spinal muscular atrophy (SMA) by FDA in 2016 and by EMA in 2017. The orally administered small-molecule risdiplam, which increases SMN protein levels similarly but also in peripheral organs, is tested in ongoing phase 2 and 3 trials. After positive results with phase 1 treatment with AAV9-SMN, the first gene therapy for SMA, a phase 3 clinical trial is ongoing. Ataluren is the first approved drug for Duchenne muscular dystrophy (DMD) patients with premature stop codon mutations and its indication has been recently extended since the age of 2 years. Exon skipping technology was and is currently tested in many phase 3 trials, and eteplirsen received a conditional approval by FDA for patients amenable to exon 51 skipping, but not by EMA. Many other compounds with different mechanisms of action are now tested in DMD by phase 2 and 3 trials, including phase 1 gene therapy. Other innovative approaches are under investigation, i.e., gene therapy in X-linked myotubular myopathy and Pompe disease, and antisense oligonucleotides in myotonic dystrophy type 1. Positive evidences are discussed about lamotrigine and ranolazine in non-dystrophic myotonias, chaperons in Pompe disease, and nucleosides in mitochondrial DNA depletion induced by thymidine kinase 2 deficiency.
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Affiliation(s)
- Giuseppe Vita
- Unit of Neurology and Neuromuscular Diseases, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy. .,Nemo Sud Clinical Centre for Neuromuscular Disorders, Messina, Italy.
| | - Gian Luca Vita
- Nemo Sud Clinical Centre for Neuromuscular Disorders, Messina, Italy
| | - Olimpia Musumeci
- Unit of Neurology and Neuromuscular Diseases, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Carmelo Rodolico
- Unit of Neurology and Neuromuscular Diseases, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy
| | - Sonia Messina
- Unit of Neurology and Neuromuscular Diseases, Department of Clinical and Experimental Medicine, University of Messina, Messina, Italy.,Nemo Sud Clinical Centre for Neuromuscular Disorders, Messina, Italy
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Li X, Yuan J, Liu L, Hu W. Antibody-LGI 1 autoimmune encephalitis manifesting as rapidly progressive dementia and hyponatremia: a case report and literature review. BMC Neurol 2019; 19:19. [PMID: 30732585 PMCID: PMC6366039 DOI: 10.1186/s12883-019-1251-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 02/01/2019] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Anti leucine-rich glioma inactivated 1 (LGI1) encephalitis is a rare autoimmune encephalitis (AE), characterized by acute or subacute cognitive impairment, faciobrachial dystonic seizures, psychiatric disturbances and hyponatremia. Antibody-LGI 1 autoimmune encephalitis (anti-LGI1 AE) has increasingly been recognized as a primary autoimmune disorder with favorable prognosis and response to treatment. CASE PRESENTATION Herein, we reported a male patient presenting as rapidly progressive dementia and hyponatremia. He had antibodies targeting LGI1 both in the cerebrospinal fluid and serum, which demonstrated the diagnosis of typical anti-LGI1 AE. The scores of Mini-Mental State Examination and Montreal Cognitive Assessment were 19/30 and 15/30, respectively. Cranial magnetic resonance images indicated hyperintensities in bilateral hippocampus. The findings of brain arterial spin labeling and Fluorine-18-fluorodeoxyglucose positron emission tomography showed no abnormal perfusion/metabolism. After the combined treatment of intravenous immunoglobulin and glucocorticoid, the patient's clinical symptoms improved obviously. CONCLUSIONS This case raises the awareness that a rapid progressive dementia with predominant memory deficits could be induced by immunoreactions against LGI1. The better recognition will be great importance for the early diagnosis, essential treatment, even a better prognosis.
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Affiliation(s)
- Xuanting Li
- Department of Neurology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020 China
| | - Junliang Yuan
- Department of Neurology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020 China
| | - Lei Liu
- Department of Neurology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 China
| | - Wenli Hu
- Department of Neurology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020 China
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Damar IH, Eroz R. Evaluation of Cases with Myotonia Congenita for Cardiovascular Risk. Medeni Med J 2019; 34:374-379. [PMID: 32821464 PMCID: PMC7433722 DOI: 10.5222/mmj.2019.93357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 12/06/2019] [Indexed: 11/05/2022] Open
Abstract
Objective Myotonia Congenita (MC) is a hereditary neuromuscular disorder caused by a mutation in chloride voltage-gated channel 1 (CLCN1) gene. The incidence of MC is estimated as 1 in 100.000. The absence of left main coronary artery (LMCA) is a rare coronary anomaly. Here we present a family with four members who have MC variation carrier and cardiovascular risk. Method The demographic features, laboratory findings, anthropometric measurements and cardiological examination of the cases were recorded. In addition, CLCN1 gene was sequenced by NGS (Next Generation Sequencing Method) and possible causes of inherited thrombophilia risk including MTHFR (A1298C), Factor V Leiden (G1691A), Factor II (G20210A), MTHFR (C677T), Factor V Cambridge (G1091C), plasminogen activator inhibitor 1 (PAI-1) 4G/5G, APOE, APOB, ITGB, ACE (ins/del), FVHR2 and FGB gene alterations were evaluated. Results Case 1 had homozygous c.1886T>C (p.Leu629Pro) alteration in CLCN1 gene and also coronary artery disease, myocardial infarction (MI) history, hyperlipidemia, primary hypertension, vertigo, lomber disc herniation and hearing loss. LMCA was not detected in coronary angiography in Case 1. Cases 2, 3 and 4 had heterozygous c.1886T>C (p.Leu629Pro) alteration with normal electrocardiographic and echocardiographic findings. Additionally, all of family members had genetic risk factors for the related gene, which lead to an increased risk of cardiovascular disease. Conclusion Since alteration of chloride channels in cardiomyocytes leads to variable myocardial involvement, cases with MC should be regularly followed for cardiovascular risk. Moreover, the cases with MC and with genetic profile associated with high cardiovascular risk should also be regularly followed up by cardiologists.
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Affiliation(s)
| | - Recep Eroz
- Duzce University Medical Faculty, Department of Medical Genetics, Duzce, Turkey
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61
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Zhou HY, Zhan FX, Tian WT, Zhang C, Wang Y, Zhu ZY, Liu XL, Xu YQ, Luan XH, Huang XJ, Chen SD, Cao L. The study of exercise tests in paroxysmal kinesigenic dyskinesia. Clin Neurophysiol 2018; 129:2435-2441. [PMID: 30293034 DOI: 10.1016/j.clinph.2018.09.004] [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: 05/29/2018] [Revised: 08/14/2018] [Accepted: 09/01/2018] [Indexed: 10/28/2022]
Abstract
OBJECTIVE To unravel if there was muscular ion channel dysfunction in paroxysmal kinesigenic dyskinesia (PKD) patients using the exercises tests (ET). METHODS Sixty PKD patients including 28 PRRT2 mutations carriers were enrolled in this study, as well as 19 hypokalaemic periodic paralysis (HypoPP) patients as the positive controls and 45 healthy subjects as the negative controls. ET including long exercise test (LET) and short exercise test (SET) was performed in the corresponding subjects. RESULTS In the LET, both the overall PKD patients and HypoPP patients had greater CMAP amplitude and area increments during exercise than healthy controls. At most 25% of PKD patients were identified from the normality with greater amplitude increment than the area. On the contrary, 50% of HypoPP patients were differentiated with greater area increment than the amplitude. More percentage of PRRT2- patients than PRRT2+ patients had abnormal average amplitude increment. Unexpectedly, five PKD patients had abnormal maximum CMAP amplitude decrements after exercise in the LET, and one had abnormal maximum immediate amplitude decrement in the SET. CONCLUSIONS Distinct ET manifestations were found in PKD patients compared to normal controls and HypoPP patients. SIGNIFICANCE Abnormal muscle membrane excitability might be involved in the mechanisms responsible for PKD.
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Affiliation(s)
- Hai-Yan Zhou
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Fei-Xia Zhan
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wo-Tu Tian
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chao Zhang
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yan Wang
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Ze-Yu Zhu
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Li Liu
- Department of Neurology, Shanghai Fengxian District Central Hospital, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, China
| | - Yang-Qi Xu
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xing-Hua Luan
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiao-Jun Huang
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Sheng-Di Chen
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Li Cao
- Department of Neurology & Institute of Neurology, Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China.
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Abstract
Skeletal muscle channelopathies are rare heterogeneous diseases with marked genotypic and phenotypic variability. These disorders cause lifetime disability and impact quality of life. Despite advances in understanding of the molecular pathology of these disorders, the diverse phenotypic manifestations remain a challenge in diagnosis, therapeutic, genetic counseling, and research planning. Electrodiagnostic testing is useful in directing the diagnosis, but has several limitations: patient discomfort, time consuming, and significant overlap of findings in muscle channelopathies. Although genetic testing is the gold standard in making a definitive diagnosis, a mutation might not be identified in many patients with a well-supported clinical diagnosis of periodic paralysis. In the recent past, there have been landmark clinical trials in non-dystrophic myotonia and periodic paralysis which are encouraging as they demonstrate the ability of robust clinical research consortia to conduct well-controlled trials of rare diseases.
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Affiliation(s)
- Lauren Phillips
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas, 75390, USA
| | - Jaya R Trivedi
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, Texas, 75390, USA.
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Mantero V, Lucchiari S, Balgera R, Comi GP, Salmaggi A, Rigamonti A. Novel Lys215Asn mutation in an Italian family with Thomsen myotonia. Neurol Sci 2018; 39:1491-1492. [PMID: 29546603 DOI: 10.1007/s10072-018-3311-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 03/08/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Vittorio Mantero
- Neurological Unit, "A. Manzoni" Hospital - ASST Lecco, Via dell'Eremo 9/11, 23900, Lecco, Italy.
| | - Sabrina Lucchiari
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), Neurology Unit, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Roberto Balgera
- Neurological Unit, "A. Manzoni" Hospital - ASST Lecco, Via dell'Eremo 9/11, 23900, Lecco, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), Neurology Unit, IRCCS Fondazione Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Andrea Salmaggi
- Neurological Unit, "A. Manzoni" Hospital - ASST Lecco, Via dell'Eremo 9/11, 23900, Lecco, Italy
| | - Andrea Rigamonti
- Neurological Unit, "A. Manzoni" Hospital - ASST Lecco, Via dell'Eremo 9/11, 23900, Lecco, Italy
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64
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Myotonia congenita in a Labrador Retriever with truncated CLCN1. Neuromuscul Disord 2018; 28:597-605. [DOI: 10.1016/j.nmd.2018.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 04/29/2018] [Accepted: 05/07/2018] [Indexed: 11/20/2022]
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65
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Portaro S, Naro A, Bramanti A, Leo A, Manuli A, Balletta T, Trinchera A, Bramanti P, Calabrò RS. Beyond the muscular involvement in non-dystrophic myotonias: The emerging role of neuromodulation. Restor Neurol Neurosci 2018; 36:459-467. [PMID: 29889082 DOI: 10.3233/rnn-170796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The central nervous system involvement, in terms of a maladaptive sensory-motor plasticity, is well known in patients with dystrophic myotonias (DMs). To date, there are no data suggesting a central nervous system involvement in non-dystrophic myotonias (NDMs). OBJECTIVE To investigate sensory-motor plasticity in patients with Myotonia Congenita (MC) and Paramyotonia Congenita (PMC) with or without mexiletine. METHODS Twelve patients with a clinical, genetic, and electromyographic evidence of MC, fifteen with PMC, and 25 healthy controls (HC) were included in the study. TMS on both primary motor cortices (M1) and a rapid paired associative stimulation (rPAS) paradigm were carried out to assess M1 excitability and sensory-motor plasticity. RESULTS patients showed a higher cortical excitability and a deterioration of the topographic specificity of rPAS aftereffects, as compared to HCs. There was no correlation among neurophysiological and clinical-demographic characteristics. Noteworthy, the patients who were under mexiletine showed a minor impairment of the topographic specificity of rPAS aftereffects as compared to those who did not take the drug. CONCLUSION our findings could suggest the deterioration of cortical sensory-motor plasticity in patients with NDMs as a trait of the disease.
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Affiliation(s)
| | - Antonino Naro
- IRCSS Centro Neurolesi Bonino Pulejo, Messina, Italy
| | - Alessia Bramanti
- Institute of Applied Sciences and Intelligent Systems "Edoardo Caianello" (ISASI), National Research Council of Italy, Messina, Italy
| | - Antonino Leo
- IRCSS Centro Neurolesi Bonino Pulejo, Messina, Italy
| | | | - Tina Balletta
- IRCSS Centro Neurolesi Bonino Pulejo, Messina, Italy
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66
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Coote DJ, Davis MR, Cabrera M, Needham M, Laing NG, Nowak KJ. Clinical Utility Gene Card for: autosomal dominant myotonia congenita (Thomsen Disease). Eur J Hum Genet 2018; 26:1072-1077. [PMID: 29695755 DOI: 10.1038/s41431-017-0065-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2017] [Revised: 09/28/2017] [Accepted: 11/23/2017] [Indexed: 11/09/2022] Open
Affiliation(s)
- David J Coote
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia; and Harry Perkins Institute of Medical Research, QQ Block, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Mark R Davis
- Neurogenetics Laboratory, Department of Diagnostic Genomics, PP Block, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Macarena Cabrera
- Department of Neurology and Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío, Seville, 41013, Spain
| | - Merrilee Needham
- Western Australian Neuroscience Institute, QEII Medical Centre, Nedlands, Western Australia 6009; Fiona Stanley Hospital, 11 Robin Warren Drive, Murdoch, WA, 6150, Australia
| | - Nigel G Laing
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia; and Harry Perkins Institute of Medical Research, QQ Block, QEII Medical Centre, Nedlands, WA, 6009, Australia.,Neurogenetics Laboratory, Department of Diagnostic Genomics, PP Block, QEII Medical Centre, Nedlands, WA, 6009, Australia
| | - Kristen J Nowak
- Centre for Medical Research, Faculty of Health and Medical Sciences, The University of Western Australia; and Harry Perkins Institute of Medical Research, QQ Block, QEII Medical Centre, Nedlands, WA, 6009, Australia. .,School of Biomedical Sciences, Faculty of Health and Medical Sciences, The University of Western Australia, Crawley, WA, Australia. .,Office of Population Health Genomics, Public and Aboriginal Health Division, Department of Health, East Perth, WA, 6004, Australia.
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67
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Molenaar JP, Voermans NC, de Jong LA, Stegeman DF, Doorduin J, van Engelen BG. Repeatability and reliability of muscle relaxation properties induced by motor cortical stimulation. J Appl Physiol (1985) 2018. [PMID: 29543137 DOI: 10.1152/japplphysiol.00455.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Impaired muscle relaxation is a feature of many neuromuscular disorders. However, few tests are available to quantify muscle relaxation. Transcranial magnetic stimulation (TMS) of the motor cortex can induce muscle relaxation by abruptly inhibiting corticospinal drive. The aim of our study was to investigate whether repeatability and reliability of TMS-induced relaxation are greater than voluntary relaxation. Furthermore, effects of sex, cooling, and fatigue on muscle relaxation properties were studied. Muscle relaxation of deep finger flexors was assessed in 25 healthy subjects (14 men and 11 women, age 39.1 ± 12.7 and 45.3 ± 8.7 yr, respectively) with handgrip dynamometry. All outcome measures showed greater repeatability and reliability in TMS-induced relaxation compared with voluntary relaxation. The within-subject coefficient of variability of normalized peak relaxation rate was lower in TMS-induced relaxation than in voluntary relaxation (3.0% vs. 19.7% in men and 6.1% vs. 14.3% in women). The repeatability coefficient was lower (1.3 vs. 6.1 s-1 in men and 2.3 vs. 3.1 s-1 in women) and the intraclass correlation coefficient was higher (0.95 vs. 0.53 in men and 0.78 vs. 0.69 in women) for TMS-induced relaxation compared with voluntary relaxation. TMS enabled demonstration of slowing effects of sex, muscle cooling, and muscle fatigue on relaxation properties that voluntary relaxation could not. In conclusion, repeatability and reliability of TMS-induced muscle relaxation were greater compared with voluntary muscle relaxation. TMS-induced muscle relaxation has the potential to be used in clinical practice for diagnostic purposes and therapy effect monitoring in patients with impaired muscle relaxation. NEW & NOTEWORTHY Transcranial magnetic stimulation (TMS)-induced muscle relaxation demonstrates greater repeatability and reliability compared with voluntary relaxation, represented by the ability to demonstrate typical effects of sex, cooling, and fatigue on muscle relaxation properties that were not seen in voluntary relaxation. In clinical practice, TMS-induced muscle relaxation could be used for diagnostic purposes and therapy effect monitoring. Furthermore, fewer subjects will be needed for future studies when using TMS to demonstrate differences in muscle relaxation properties.
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Affiliation(s)
- J P Molenaar
- Department of Neurology, Radboud University Medical Center , Nijmegen , The Netherlands.,Donders Institute for Brain, Cognition and Behavior, Nijmegen , The Netherlands
| | - N C Voermans
- Department of Neurology, Radboud University Medical Center , Nijmegen , The Netherlands.,Donders Institute for Brain, Cognition and Behavior, Nijmegen , The Netherlands
| | - L A de Jong
- Department of Neurology, Radboud University Medical Center , Nijmegen , The Netherlands.,Donders Institute for Brain, Cognition and Behavior, Nijmegen , The Netherlands
| | - D F Stegeman
- Department of Neurology, Radboud University Medical Center , Nijmegen , The Netherlands.,Donders Institute for Brain, Cognition and Behavior, Nijmegen , The Netherlands
| | - J Doorduin
- Department of Neurology, Radboud University Medical Center , Nijmegen , The Netherlands.,Donders Institute for Brain, Cognition and Behavior, Nijmegen , The Netherlands
| | - B G van Engelen
- Department of Neurology, Radboud University Medical Center , Nijmegen , The Netherlands.,Donders Institute for Brain, Cognition and Behavior, Nijmegen , The Netherlands
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68
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Abstract
Voltage-gated sodium channels belong to the superfamily of voltage-gated cation channels. Their structure is based on domains comprising a voltage sensor domain (S1-S4 segments) and a pore domain (S5-S6 segments). Mutations in positively charged residues of the S4 segments may allow protons or cations to pass directly through the gating pore constriction of the voltage sensor domain; these anomalous currents are referred to as gating pore or omega (ω) currents. In the skeletal muscle disorder hypokalemic periodic paralysis, and in arrhythmic dilated cardiomyopathy, inherited mutations of S4 arginine residues promote omega currents that have been shown to be a contributing factor in the pathogenesis of these sodium channel disorders. Characterization of gating pore currents in these channelopathies and with artificial mutations has been possible by measuring the voltage-dependence and selectivity of these leak currents. The basis of gating pore currents and the structural basis of S4 movement through the gating pore has also been studied extensively with molecular dynamics. These simulations have provided valuable insight into the nature of S4 translocation and the physical basis for the effects of mutations that promote permeation of protons or cations through the gating pore.
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Affiliation(s)
- J R Groome
- Department of Biological Sciences, Idaho State University, Pocatello, ID, 83209, USA.
| | - A Moreau
- Institut NeuroMyogene, ENS de Lyon, Site MONOD, Lyon, France
| | - L Delemotte
- Science for Life Laboratory, Department of Physics, KTH Royal Institute of Technology, Box 1031, 171 21, Solna, Sweden
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69
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Suokas K, Palmio J, Sandell S, Udd B, Hietaharju A. Pain in SCN4A Mutated P.A1156T muscle sodium channelopathy-a postal survey. Muscle Nerve 2017; 57:1014-1017. [PMID: 29272040 DOI: 10.1002/mus.26050] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2017] [Indexed: 01/26/2023]
Abstract
INTRODUCTION The p.A1156T mutation alters the function of the voltage-gated sodium channel Nav1.4 on the muscle sarcolemma, causing a channelopathy without overt myotonia or periodic paralysis but with myalgic pain. METHODS A postal survey was conducted to assess the prevalence and characteristics of pain and related symptoms in individuals with the p.A1156T mutation. A specific questionnaire, intensity and interference subscales of the Brief Pain Inventory, pain drawing, Widespread Pain Index, quality of life (RAND-36), and the Beck Depression Inventory were completed. RESULTS Twenty of 24 patients replied. Current pain was reported by 16 respondents; the other 4 had experienced pain previously. Most commonly, pain was widespread and exercise-induced. The severity and the impact of pain on daily life were considerable, although varied. DISCUSSION This sodium channelopathy is another entity in the growing number of diseases causing widespread myalgic pain that resembles the pain seen in fibromyalgia syndrome. Muscle Nerve 57: 1014-1017, 2018.
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Affiliation(s)
- Kimmo Suokas
- Department of Neurology, Tampere University Hospital, P.O. Box 2000 FI-33521, Tampere, Finland
| | - Johanna Palmio
- Neuromuscular Research Center, University Hospital of Tampere, Tampere, Finland
| | - Satu Sandell
- Department of Neurology, Southern Ostrobothnia Hospital District, Seinäjoki, Finland
| | - Bjarne Udd
- Neuromuscular Research Center, University Hospital of Tampere, Tampere, Finland
| | - Aki Hietaharju
- Department of Neurology, Tampere University Hospital, P.O. Box 2000 FI-33521, Tampere, Finland
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70
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Andersen G, Hedermann G, Witting N, Duno M, Andersen H, Vissing J. The antimyotonic effect of lamotrigine in non-dystrophic myotonias: a double-blind randomized study. Brain 2017; 140:2295-2305. [PMID: 29050397 DOI: 10.1093/brain/awx192] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 06/17/2017] [Indexed: 11/14/2022] Open
Abstract
Mexiletine is the only drug with proven effect for treatment of non-dystrophic myotonia, but mexiletine is expensive, has limited availability and several side effects. There is therefore a need to identify other pharmacological compounds that can alleviate myotonia in non-dystrophic myotonias. Like mexiletine, lamotrigine is a sodium channel blocker, but unlike mexiletine, lamotrigine is available, inexpensive, and well tolerated. We investigated the potential of using lamotrigine for treatment of myotonia in patients with non-dystrophic myotonias. In this, randomized double-blind, placebo-controlled, two-period cross-over study, we included adult outpatients recruited from all of Denmark with clinical myotonia and genetically confirmed myotonia congenita and paramyotonia congenita for investigation at the Copenhagen Neuromuscular Center. A pharmacy produced the medication and placebo, and randomized patients in blocks of 10. Participants and investigators were all blinded to treatment until the end of the trial. In two 8-week periods, oral lamotrigine or placebo capsules were provided once daily, with increasing doses (from 25 mg, 50 mg, 150 mg to 300 mg) every second week. The primary outcome was a severity score of myotonia, the Myotonic Behaviour Scale ranging from asymptomatic (score 1) to invalidating myotonia (score 6), reported by the participants during Weeks 0 and 8 in each treatment period. Clinical myotonia was also measured and side effects were monitored. The study was registered at ClinicalTrials.gov (NCT02159963) and EudraCT (2013-003309-24). We included 26 patients (10 females, 16 males, age: 19-74 years) from 13 November 2013 to 6 July 2015. Twenty-two completed the entire study. One patient withdrew due to an allergic reaction to lamotrigine. Three patients withdrew for reasons not related to the trial intervention. The Myotonic Behaviour Scale at baseline was 3.2 ± 1.1, which changed after treatment with lamotrigine by 1.3 ± 0.2 scores (P < 0.001), but not with placebo (0.2 ± 0.1 scores, P = 0.4). The estimated effect size was 1.0 ± 0.2 (95% confidence interval = 0.5-1.5, P < 0.001, n = 22). The standardized effect size of lamotrigine was 1.5 (confidence interval: 1.2-1.8). Number needed to treat was 2.6 (P = 0.006, n = 26). No adverse or unsuspected event occurred. Common side effects occurred in both treatment groups; number needed to harm was 5.2 (P = 0.11, n = 26). Lamotrigine effectively reduced myotonia, emphasized by consistency between effects on patient-related outcomes and objective outcomes. The frequency of side effects was acceptable. Considering this and the high availability and low cost of the drug, we suggest that lamotrigine should be used as the first line of treatment for myotonia in treatment-naive patients with non-dystrophic myotonias.
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Affiliation(s)
- Grete Andersen
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Denmark
| | - Gitte Hedermann
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Denmark
| | - Nanna Witting
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Denmark
| | - Morten Duno
- Department of Molecular Genetics, University of Copenhagen, Denmark
| | | | - John Vissing
- Department of Neurology, Copenhagen Neuromuscular Center, University of Copenhagen, Denmark
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Ke Q, Ye J, Tang S, Wang J, Luo B, Ji F, Zhang X, Yu Y, Cheng X, Li Y. N1366S mutation of human skeletal muscle sodium channel causes paramyotonia congenita. J Physiol 2017; 595:6837-6850. [PMID: 28940424 DOI: 10.1113/jp274877] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/15/2017] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Paramyotonia congenita is a hereditary channelopathy caused by missense mutations in the SCN4A gene, which encodes the α subunit of the human skeletal muscle voltage-gated sodium channel NaV1.4. Affected individuals suffered from myotonia and paralysis of muscles, which were aggravated by exposure to cold. We report a three-generation Chinese family with patients presenting paramyotonia congenita and identify a novel N1366S mutation of NaV1.4. Whole-cell electrophysiological recordings of the N1366S channel reveal a gain-of-function change of gating in response to cold. Modelling and molecular dynamic simulation data suggest that an arginine-to-serine substitution at position 1366 increases the distance from N1366 to R1454 and disrupts the hydrogen bond formed between them at low temperature. We demonstrate that N1366S is a disease-causing mutation and that the temperature-sensitive alteration of N1366S channel activity may be responsible for the pronounced paramyotonia congenita symptoms of these patients. ABSTRACT Paramyotonia congenita is an autosomal dominant skeletal muscle channelopathy caused by missense mutations in SCN4A, the gene encoding the α subunit of the human skeletal muscle voltage-gated sodium channel NaV1.4. We report a three-generation family in which six members present clinical symptoms of paramyotonia congenita characterized by a marked worsening of myotonia by cold and by the presence of clear episodes of paralysis. We identified a novel mutation in SCN4A (Asn1366Ser, N1366S) in all patients in the family but not in healthy relatives or in 500 normal control subjects. Functional analysis of the channel protein expressed in HEK293 cells by whole-cell patch clamp recording revealed that the N1366S mutation led to significant alterations in the gating process of the NaV1.4 channel. The N1366S mutant displayed a cold-induced hyperpolarizing shift in the voltage dependence of activation and a depolarizing shift in fast inactivation, as well as a reduced rate of fast inactivation and accelerated recovery from fast inactivation. In addition, homology modelling and molecular dynamic simulation of N1366S and wild-type NaV1.4 channels indicated that the arginine-to-serine substitution disrupted the hydrogen bond formed between N1366 and R1454. Together, our results suggest that N1366S is a gain-of-function mutation of NaV1.4 at low temperature and the mutation may be responsible for the clinical symptoms of paramyotonia congenita in the affected family and constitute a basis for studies into its pathogenesis.
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Affiliation(s)
- Qing Ke
- Department of Neurology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jia Ye
- Department of Physiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Siyang Tang
- Department of Physiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Jin Wang
- Institute of Medical Sciences and Department of Pharmacology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Benyan Luo
- Department of Neurology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Fang Ji
- Department of Neurology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Xu Zhang
- Bejing Epigen Medical Institute, Beijing, China
| | - Ye Yu
- Institute of Medical Sciences and Department of Pharmacology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaoyang Cheng
- Department of Anatomy, Histology and Embryology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yuezhou Li
- Department of Physiology, Institute of Neuroscience, Key Laboratory of Medical Neurobiology of Ministry of Health of China, Zhejiang Province Key Laboratory of Tissue Engineering and Regenerative Medicine, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
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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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73
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Matthews E, Silwal A, Sud R, Hanna MG, Manzur AY, Muntoni F, Munot P. Skeletal Muscle Channelopathies: Rare Disorders with Common Pediatric Symptoms. J Pediatr 2017; 188:181-185.e6. [PMID: 28662944 DOI: 10.1016/j.jpeds.2017.05.081] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 03/31/2017] [Accepted: 05/31/2017] [Indexed: 10/19/2022]
Abstract
OBJECTIVE To ascertain the presenting symptoms of children with skeletal muscle channelopathies to promote early diagnosis and treatment. STUDY DESIGN Retrospective case review of 38 children with a skeletal muscle channelopathy attending the specialist pediatric neuromuscular service at Great Ormond Street Hospital over a 15-year period. RESULTS Gait disorder and leg cramps are a frequent presentation of myotonic disorders (19 of 29). Strabismus or extraocular myotonia (9 of 19) and respiratory and/or bulbar symptoms (11 of 19) are common among those with sodium channelopathy. Neonatal hypotonia was observed in periodic paralysis. Scoliosis and/or contractures were demonstrated in 6 of 38 children. School attendance or ability to engage fully in all activities was often limited (25 of 38). CONCLUSIONS Children with skeletal muscle channelopathies frequently display symptoms that are uncommon in adult disease. Any child presenting with abnormal gait, leg cramps, or strabismus, especially if intermittent, should prompt examination for myotonia. Those with sodium channel disease should be monitored for respiratory or bulbar complications. Neonatal hypotonia can herald periodic paralysis. Early diagnosis is essential for children to reach their full educational potential.
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Affiliation(s)
- Emma Matthews
- Medical Research Council Center for Neuromuscular Diseases, University College London and National Hospital for Neurology and Neurosurgery, London, UK.
| | - Arpana Silwal
- Dubowitz Neuromuscular Center and MRC Center for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Richa Sud
- Neurogenetics Unit, Institute of Neurology, London, UK
| | - Michael G Hanna
- Medical Research Council Center for Neuromuscular Diseases, University College London and National Hospital for Neurology and Neurosurgery, London, UK
| | - Adnan Y Manzur
- Dubowitz Neuromuscular Center and MRC Center for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Francesco Muntoni
- Dubowitz Neuromuscular Center and MRC Center for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Pinki Munot
- Dubowitz Neuromuscular Center and MRC Center for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
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Hamedani AG, Gold DR. Eyelid Dysfunction in Neurodegenerative, Neurogenetic, and Neurometabolic Disease. Front Neurol 2017; 8:329. [PMID: 28769865 PMCID: PMC5513921 DOI: 10.3389/fneur.2017.00329] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/23/2017] [Indexed: 12/18/2022] Open
Abstract
Eye movement abnormalities are among the earliest clinical manifestations of inherited and acquired neurodegenerative diseases and play an integral role in their diagnosis. Eyelid movement is neuroanatomically linked to eye movement, and thus eyelid dysfunction can also be a distinguishing feature of neurodegenerative disease and complements eye movement abnormalities in helping us to understand their pathophysiology. In this review, we summarize the various eyelid abnormalities that can occur in neurodegenerative, neurogenetic, and neurometabolic diseases. We discuss eyelid disorders, such as ptosis, eyelid retraction, abnormal spontaneous and reflexive blinking, blepharospasm, and eyelid apraxia in the context of the neuroanatomic pathways that are affected. We also review the literature regarding the prevalence of eyelid abnormalities in different neurologic diseases as well as treatment strategies (Table 1).
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Affiliation(s)
- Ali G Hamedani
- Department of Neurology, Hospital of the University of Pennsylvania, Philadelphia, PA, United States
| | - Daniel R Gold
- Department of Neurology, Johns Hopkins Hospital, Baltimore, MD, United States.,Department of Ophthalmology, Johns Hopkins Hospital, Baltimore, MD, United States.,Department of Neurosurgery, Johns Hopkins Hospital, Baltimore, MD, United States.,Department of Otolaryngology - Head and Neck Surgery, Johns Hopkins Hospital, Baltimore, MD, United States
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75
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Yamamoto J, Hokkoku K, Hatanaka Y, Sakoda S, Yuan JH, Sonoo M. An unusual case of sodium channel myotonia with transient weakness upon initiating movements which is characteristic in Becker disease. Rinsho Shinkeigaku 2017; 57:287-292. [PMID: 28552867 DOI: 10.5692/clinicalneurol.cn-000980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We reported a 32-year-old man who was a sporadic case of myotonic syndrome with muscle stiffness or transient weakness of limbs upon initiating movements after rest. On examination, he showed painless myotonia with warm-up phenomenon, Hercules-like hypertrophic musculature and myotonic discharges in EMG. The clinical findings resembled to those of Becker disease rather than Thomsen disease. But electrodiagnosis suggested sodium channel myotonia instead of chloride channelopathy. Genetic testing detected a novel missense mutation (p.V1166A) in the SCN4A gene but not in the CLCN1 gene. Transient weakness upon initiating movements is usually observed in Becker disease but rare in Thomsen disease, which is not reported in sodium channel myotonia so far. He was probably the first case of sodium channel myotonia with transient weakness upon initiating movements, which was confirmed by 10 Hz repetitive nerve stimulation test as depolarization block.
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Affiliation(s)
- Junpei Yamamoto
- Department of Neurology, Teikyo University School of Medicine
| | - Keiichi Hokkoku
- Department of Neurology, Teikyo University School of Medicine
| | - Yuki Hatanaka
- Department of Neurology, Teikyo University School of Medicine
| | - Shunichi Sakoda
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences
| | - Jun-Hui Yuan
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences
| | - Masahiro Sonoo
- Department of Neurology, Teikyo University School of Medicine
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76
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Lowrie M, Garosi L. Classification of Involuntary Movements in Dogs: Myoclonus and Myotonia. J Vet Intern Med 2017; 31:979-987. [PMID: 28557061 PMCID: PMC5508344 DOI: 10.1111/jvim.14771] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/07/2017] [Accepted: 04/27/2017] [Indexed: 12/25/2022] Open
Abstract
Myoclonus is a sudden brief, involuntary muscle jerk. Of all the movement disorders, myoclonus is the most difficult to encapsulate into any simple framework. On the one hand, a classification system is required that is clinically useful to aid in guiding diagnosis and treatment. On the other hand, there is need for a system that organizes current knowledge regarding biological mechanisms to guide scientific research. These 2 needs are distinct, making it challenging to develop a robust classification system suitable for all purposes. We attempt to classify myoclonus as “epileptic” and “nonepileptic” based on its association with epileptic seizures. Myotonia in people may be divided into 2 clinically and molecularly defined forms: (1) nondystrophic myotonias and (2) myotonic dystrophies. The former are a group of skeletal muscle channelopathies characterized by delayed skeletal muscle relaxation. Many distinct clinical phenotypes are recognized in people, the majority relating to mutations in skeletal muscle voltage‐gated chloride (CLCN1) and sodium channel (SCN4A) genes. In dogs, myotonia is associated with mutations in CLCN1. The myotonic dystrophies are considered a multisystem clinical syndrome in people encompassing 2 clinically and molecularly defined forms designated myotonic dystrophy types 1 and 2. No mutation has been linked to veterinary muscular dystrophies. We detail veterinary examples of myotonia and attempt classification according to guidelines used in humans. This more precise categorization of myoclonus and myotonia aims to promote the search for molecular markers contributing to the phenotypic spectrum of disease. Our work aimed to assist recognition for these 2 enigmatic conditions.
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Affiliation(s)
- M Lowrie
- Dovecote Veterinary Hospital, Derby, UK
| | - L Garosi
- Davies Veterinary Specialists, Hitchin, UK
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77
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Al-Ghamdi F, Darras BT, Ghosh PS. Spectrum of Nondystrophic Skeletal Muscle Channelopathies in Children. Pediatr Neurol 2017; 70:26-33. [PMID: 28325641 DOI: 10.1016/j.pediatrneurol.2017.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Accepted: 02/10/2017] [Indexed: 01/21/2023]
Abstract
BACKGROUND The nondystrophic skeletal muscle channelopathies are a group of disorders caused by mutations of various voltage-gated ion channel genes, including nondystrophic myotonia and periodic paralysis. METHODS We identified patients with a diagnosis of muscle channelopathy from our neuromuscular database in a tertiary care pediatric center from 2005 to 2015. We then performed a retrospective review of their medical records for demographic characteristics, clinical features, investigations, treatment, and follow-up. RESULTS Thirty-three patients were identified. Seventeen had nondystrophic myotonia. Seven of them had chloride channelopathy (four Becker disease and three Thomsen disease). Warm-up phenomenon and muscle hypertrophy were common clinical manifestations in this subgroup. Ten patients had sodium channelopathy (four paramyotonia congenita and six other sodium channel myotonia). Stiffness of the facial muscles was an important presenting symptom, and eyelid myotonia was a common clinical finding in this subgroup. The majority of these patients had electrical myotonia. Mexiletine was effective in controlling the symptoms in patients who had received treatment. Sixteen children had periodic paralysis (four hyperkalemic periodic paralysis, eight hypokalemic periodic paralysis, and four Andersen-Tawil syndrome). Acetazolamide was commonly used to prevent paralytic attacks and was found to be effective. CONCLUSIONS Nondystrophic muscle channelopathies present with diverse clinical manifestations (myotonia, muscle hypertrophy, proximal weakness, swallowing difficulties, and periodic paralysis). Cardiac arrhythmias are potentially life threatening in Andersen-Tawil syndrome. Timely identification of these disorders is helpful for effective symptomatic management and genetic counseling.
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Affiliation(s)
- Fouad Al-Ghamdi
- Department of Neurology, Boston Children's Hospital, Boston, MA
| | - Basil T Darras
- Department of Neurology, Boston Children's Hospital, Boston, MA
| | - Partha S Ghosh
- Department of Neurology, Boston Children's Hospital, Boston, MA.
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78
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Poroca DR, Pelis RM, Chappe VM. ClC Channels and Transporters: Structure, Physiological Functions, and Implications in Human Chloride Channelopathies. Front Pharmacol 2017; 8:151. [PMID: 28386229 PMCID: PMC5362633 DOI: 10.3389/fphar.2017.00151] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/09/2017] [Indexed: 02/04/2023] Open
Abstract
The discovery of ClC proteins at the beginning of the 1990s was important for the development of the Cl- transport research field. ClCs form a large family of proteins that mediate voltage-dependent transport of Cl- ions across cell membranes. They are expressed in both plasma and intracellular membranes of cells from almost all living organisms. ClC proteins form transmembrane dimers, in which each monomer displays independent ion conductance. Eukaryotic members also possess a large cytoplasmic domain containing two CBS domains, which are involved in transport modulation. ClC proteins function as either Cl- channels or Cl-/H+ exchangers, although all ClC proteins share the same basic architecture. ClC channels have two gating mechanisms: a relatively well-studied fast gating mechanism, and a slow gating mechanism, which is poorly defined. ClCs are involved in a wide range of physiological processes, including regulation of resting membrane potential in skeletal muscle, facilitation of transepithelial Cl- reabsorption in kidneys, and control of pH and Cl- concentration in intracellular compartments through coupled Cl-/H+ exchange mechanisms. Several inherited diseases result from C1C gene mutations, including myotonia congenita, Bartter's syndrome (types 3 and 4), Dent's disease, osteopetrosis, retinal degeneration, and lysosomal storage diseases. This review summarizes general features, known or suspected, of ClC structure, gating and physiological functions. We also discuss biophysical properties of mammalian ClCs that are directly involved in the pathophysiology of several human inherited disorders, or that induce interesting phenotypes in animal models.
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Affiliation(s)
- Diogo R Poroca
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
| | - Ryan M Pelis
- Department of Pharmacology, Dalhousie University, Halifax NS, Canada
| | - Valérie M Chappe
- Department of Physiology and Biophysics, Dalhousie University, Halifax NS, Canada
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79
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Andersen G, Løkken N, Vissing J. Aerobic training in myotonia congenita: Effect on myotonia and fitness. Muscle Nerve 2017; 56:696-699. [DOI: 10.1002/mus.25549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/22/2016] [Accepted: 12/28/2016] [Indexed: 11/06/2022]
Affiliation(s)
- Grete Andersen
- Copenhagen Neuromuscular Center, Department of Neurology, RigshospitaletUniversity of Copenhagen3342 Blegdamsvej 9, 2100 Denmark
| | - Nicoline Løkken
- Copenhagen Neuromuscular Center, Department of Neurology, RigshospitaletUniversity of Copenhagen3342 Blegdamsvej 9, 2100 Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, RigshospitaletUniversity of Copenhagen3342 Blegdamsvej 9, 2100 Denmark
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80
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Ginanneschi F, Mignarri A, Lucchiari S, Ulzi G, Comi GP, Rossi A, Dotti MT. Neuromuscular excitability changes produced by sustained voluntary contraction and response to mexiletine in myotonia congenita. Neurophysiol Clin 2017; 47:247-252. [PMID: 28153715 DOI: 10.1016/j.neucli.2017.01.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 01/03/2017] [Indexed: 02/02/2023] Open
Abstract
OBJECTIVE To investigate the cause of transient weakness in myotonia congenita (MC) and the mechanism of action of mexiletine in reducing weakness. METHODS The changes in neuromuscular excitability produced by 1min of maximal voluntary contractions (MVC) were measured on the amplitude of compound muscle action potentials (CMAP) in two patients with either recessive or dominant MC, compared to control values obtained in 20 healthy subjects. Measurements were performed again in MC patients after mexiletine therapy. RESULTS Transient reduction in maximal CMAP amplitude lasting several minutes after MVC was evident in MC patients, whereas no change was observed in controls. Mexiletine efficiently reduced this transient CMAP depression in both patients. DISCUSSION Transient CMAP depression following sustained MVC may represent the electrophysiological correlate of the weakness clinically experienced by the patients. In MC, the low chloride conductance could induce self-sustaining action potentials after MVC, determining progressive membrane depolarization and a loss of excitability of muscle fibers, thus resulting in transient paresis. Mexiletine may prevent conduction block due to excessive membrane depolarization, thus reducing the transient CMAP depression following sustained MVC.
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Affiliation(s)
- Federica Ginanneschi
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy.
| | - Andrea Mignarri
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy
| | - Sabrina Lucchiari
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Gianna Ulzi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Giacomo P Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Alessandro Rossi
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy
| | - Maria Teresa Dotti
- Department of Medical, Surgical and Neurological Sciences, Neurology-Neurophysiology Unit, University of Siena, Policlinico Le Scotte, Viale Bracci 1, 53100 Siena, Italy
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81
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Kato H, Kokunai Y, Dalle C, Kubota T, Madokoro Y, Yuasa H, Uchida Y, Ikeda T, Mochizuki H, Nicole S, Fontaine B, Takahashi MP, Mitake S. A case of non-dystrophic myotonia with concomitant mutations in the SCN4A and CLCN1 genes. J Neurol Sci 2016; 369:254-258. [PMID: 27653901 DOI: 10.1016/j.jns.2016.08.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 11/17/2022]
Abstract
Non-dystrophic myotonias are caused by mutations of either the skeletal muscle chloride (CLCN1) or sodium channel (SCN4A) gene. They exhibit several distinct phenotypes, including myotonia congenita, paramyotonia congenita and sodium channel myotonia, and a genotype-phenotype correlation has been established. However, there are atypical cases that do not fit with the standard classification. We report a case of 27-year-old male who had non-dystrophic myotonia with periodic paralysis and two heterozygous mutations, E950K in CLCN1 and F1290L in SCN4A. His mother, who exhibited myotonia without paralytic attack, only harbored E950K, and no mutations were identified in his asymptomatic father. Therefore, the E950K mutation was presumed to be pathogenic, although it was reported as an extremely rare genetic variant. The proband experienced paralytic attacks that lasted for weeks and were less likely to be caused by CLCN1 mutation alone. Functional analysis of the F1290L mutant channel heterologously expressed in cultured cells revealed enhanced activation inducing membrane hyperexcitability. We therefore propose that the two mutations had additive effects on membrane excitability that resulted in more prominent myotonia in the proband. Our case stresses the value of performing genetic analysis of both CLCN1 and SCN4A genes for myotonic patients with an atypical phenotype.
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Affiliation(s)
- Hideki Kato
- Department of Neurology, Tosei General Hospital, Japan
| | - Yosuke Kokunai
- Department of Neurology, Osaka University Graduate School of Medicine, Japan; INSERM U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière - ICM and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, 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 and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, France
| | - Tomoya Kubota
- Department of Neurology, Osaka University Graduate School of Medicine, Japan; Department of Biochemistry and Molecular Biology, The University of Chicago, United States; Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Japan
| | - Yuta Madokoro
- Department of Neurology, Tosei General Hospital, Japan
| | | | - Yuto Uchida
- Department of Neurology, Tosei General Hospital, Japan
| | | | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Japan
| | - 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 and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, France
| | - 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 and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, France
| | - Masanori P Takahashi
- Department of Neurology, Osaka University Graduate School of Medicine, Japan; Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Japan.
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82
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Yang X, Jia H, An R, Xi J, Xu Y. Sequence CLCN1 and SCN4A in patients with Nondystrophic myotonias in Chinese populations: Genetic and pedigree analysis of 10 families and review of the literature. Channels (Austin) 2016; 11:55-65. [PMID: 27415035 DOI: 10.1080/19336950.2016.1212140] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Myotonia congenita (MC), paramyotonia congenita (PC) and sodium channel myotonias(SCM) were belonged to Non-dystrophic myotonias, in which muscle relaxation is delayed after voluntary or evoked contraction. These diseases can not be simply distinguished only based on symptoms and signs but also on genetics: more than 100 mutations in the CLCN1 gene have been associated with MC, while at least 20 mutations in the SCN4A gene have been associated with PC and SCM. Most of these genetics studies have been conducted outside China, only several MC, PC, and SCM families accepted gene scan were reported in China. Therefore we analyzed genetic mutations in CLCN1 and SCN4A in 10 Chinese families clinically diagnosed with Non-dystrophic myotonias. Our result revealed 12 potential disease-causing mutations(3 mutations were novel) that were present in the probands and affected family members. We also reviewed all available literature on mutations linked to these 3 disease in Chinese populations. Our results may help identify genetic determinants as well as clarify genotype-phenotype relationships.
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Affiliation(s)
- Xinglong Yang
- a Department of Neurology , West China Hospital, Sichuan University , Chengdu , Sichuan Province , P.R. China
| | - Hua Jia
- a Department of Neurology , West China Hospital, Sichuan University , Chengdu , Sichuan Province , P.R. China
| | - Ran An
- a Department of Neurology , West China Hospital, Sichuan University , Chengdu , Sichuan Province , P.R. China
| | - Jing Xi
- a Department of Neurology , West China Hospital, Sichuan University , Chengdu , Sichuan Province , P.R. China
| | - Yanming Xu
- a Department of Neurology , West China Hospital, Sichuan University , Chengdu , Sichuan Province , P.R. China
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83
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Jen JC, Ashizawa T, Griggs RC, Waters MF. Rare neurological channelopathies--networks to study patients, pathogenesis and treatment. Nat Rev Neurol 2016; 12:195-203. [PMID: 26943780 DOI: 10.1038/nrneurol.2016.18] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Each of the thousands of rare neurological diseases requires a widely distributed network of centres, investigators and patients, so as to foster multidisciplinary investigations and involve sufficient numbers of patients in the discovery of disease pathogenesis and novel treatment. In this Review, we highlight the value of this collaborative approach in patient-oriented research into rare neurological channelopathies. Two networks, the Consortium for Clinical Investigations of Neurological Channelopathies (CINCH) and the Clinical Research Consortium for Studies of Cerebellar Ataxias (CRC-SCA), provide a link between patients with rare channelopathies and investigators who are studying disease pathogenesis and developing novel treatments. Interactions between patients, researchers and advocacy groups promote shared agendas that benefit patient education and recruitment, research collaboration and funding, and training and mentoring of junior investigators who are attracted to the study of the diseases that provide the focus for the two networks. Here, we discuss how linkage of national and international centres has enabled recruitment of study participants, provided opportunities for novel studies of pathogenesis, and facilitated successful clinical trials.
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Affiliation(s)
- Joanna C Jen
- Departments of Neurology and Neurobiology, David Geffen School of Medicine, University of California, 710 Westwood Plaza, Los Angeles, California 90095, USA
| | - Tetsuo Ashizawa
- McKnight Brain Institute &Department of Neurology, University of Florida, 1149 South Newell Drive, Gainsville, Florida 32611, USA
| | - Robert C Griggs
- Departments of Neurology, Medicine, Pathology and Laboratory Medicine, and Pediatrics, and Center for Human Experimental Therapeutics, University of Rochester School of Medicine and Dentistry, 601 Elmwood Avenue, Box CU 420669, Rochester, New York 14642, USA
| | - Michael F Waters
- Departments of Neurology, Neuroscience and Biomedical Engineering, College of Medicine, University of Florida, 100 Newell Road, Gainesville, Florida 32610, USA
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84
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Liu XL, Huang XJ, Luan XH, Zhou HY, Wang T, Wang JY, Chen SD, Tang HD, Cao L. Mutations of SCN4A gene cause different diseases: 2 case reports and literature review. Channels (Austin) 2016; 9:82-7. [PMID: 25839108 DOI: 10.1080/19336950.2015.1012945] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
SCN4A encodes the Nav1.4 channel and mutations in SCN4A lead to different ionic channelopathies. In this study, one sporadic individual of periodic paralysis, one paramyotonia family and 200 normal healthy controls are enrolled. Genomic DNA was extracted from peripheral blood leukocytes, followed by polymerase chain reaction and DNA sequencing of candidate genes, including SCN4A and CACNA1S. As a result, heterozygous mutations c.2024G>A (R675Q) and c.1333G>A (V445M) of gene SCN4A were identified in the hypokalemic periodic paralysis patient and the paramyotonia congenita family respectively. Both mutations were not detected in healthy controls. Compared with reported cases, patients with mutation R675Q usually do not present hypokalemic periodic paralysis but hyperkalemic or normokalemic periodic paralysis. The mutation V445M was first reported in Chinese patients with nondystrophic myotonias. In addition, we carried out literature review by summarizing clinical features of the 2 mutations and establish the genotype-phenotype correlations to provide guidance for diagnosis.
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Affiliation(s)
- Xiao-li Liu
- a Department of Neurology ; Rui Jin Hospital & Rui Jin Hospital North ; Shanghai Jiao Tong University School of Medicine ; Shanghai , China
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85
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Hahn C, Salajegheh MK. Myotonic disorders: A review article. IRANIAN JOURNAL OF NEUROLOGY 2016; 15:46-53. [PMID: 27141276 PMCID: PMC4852070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
The myotonic disorders are a heterogeneous group of genetically determined diseases that are unified by the presence of myotonia, which is defined as failure of muscle relaxation after activation. The presentation of these disorders can range from asymptomatic electrical myotonia, as seen in some forms of myotonia congenita (MC), to severe disability with muscle weakness, cardiac conduction defects, and other systemic features as in myotonic dystrophy type I (DM1). In this review, we describe the clinical features and pathophysiology of the different myotonic disorders, their laboratory and electrophysiologic findings and briefly review the currently available treatments.
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Affiliation(s)
- Chris Hahn
- 1 Department of Neurology, Brigham and Women’s Hospital, Harvard Medical School, Boston, USA
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86
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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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87
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The differential diagnosis of myotonic syndromes: A case report-guided and neurophysiologic approach. J Neurol Sci 2016; 360:98-9. [DOI: 10.1016/j.jns.2015.11.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Revised: 11/24/2015] [Accepted: 11/28/2015] [Indexed: 11/23/2022]
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88
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Araki K, Nakanishi H, Nakamura T, Atsuta N, Yamada S, Hijikata Y, Hashizume A, Suzuki K, Katsuno M, Sobue G. Myotonia-like symptoms in a patient with spinal and bulbar muscular atrophy. Neuromuscul Disord 2015; 25:913-5. [DOI: 10.1016/j.nmd.2015.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 08/11/2015] [Accepted: 08/14/2015] [Indexed: 10/23/2022]
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89
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Vindas-Smith R, Fiore M, Vásquez M, Cuenca P, del Valle G, Lagostena L, Gaitán-Peñas H, Estevez R, Pusch M, Morales F. Identification and Functional Characterization ofCLCN1Mutations Found in Nondystrophic Myotonia Patients. Hum Mutat 2015; 37:74-83. [DOI: 10.1002/humu.22916] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 09/25/2015] [Indexed: 10/22/2022]
Affiliation(s)
- Rebeca Vindas-Smith
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
| | - Michele Fiore
- Istituto di Biofisica; CNR; Via De Marini 6 Genova Italy
| | - Melissa Vásquez
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
| | - Patricia Cuenca
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
- Escuela de Medicina; Universidad de Costa Rica; Curridabat San José Costa Rica
| | - Gerardo del Valle
- Laboratorio de Neurofisiología (Neurolab); Curridabat San José Costa Rica
| | | | - Héctor Gaitán-Peñas
- Departament de Ciències Fisiològiques II; Unitat de Fisiologia; Universitat de Barcelona; Carrer Feixa Llarga s/n, L'Hospitalet de Llobregat Barcelona Spain
- U-750, Centro de Investigación en red de enfermedades raras (CIBERER); ISCIII; Barcelona Spain
| | - Raúl Estevez
- Departament de Ciències Fisiològiques II; Unitat de Fisiologia; Universitat de Barcelona; Carrer Feixa Llarga s/n, L'Hospitalet de Llobregat Barcelona Spain
- U-750, Centro de Investigación en red de enfermedades raras (CIBERER); ISCIII; Barcelona Spain
| | - Michael Pusch
- Istituto di Biofisica; CNR; Via De Marini 6 Genova Italy
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA); Universidad de Costa Rica; San José Costa Rica
- Centro de Investigación en Neurociencias (CIN); Universidad de Costa Rica; San José Costa Rica
- Escuela de Medicina; Universidad de Costa Rica; Curridabat San José Costa Rica
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90
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Heidari MM, Khatami M, Nafissi S, Hesami-Zokai F, Khorrami A. Mutation analysis in exons 22 and 24 of SCN4A gene in Iranian patients with non-dystrophic myotonia. IRANIAN JOURNAL OF NEUROLOGY 2015; 14:190-4. [PMID: 26885337 PMCID: PMC4754597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Non-dystrophic myotonias are a heterogeneous set of skeletal, muscular channelopathies, which have been associated with point mutations within sodium channel α-subunit (SCN4A) gene. Because exons 22 and 24 of SCN4A gene are recognized as hot spots for this disease, the purpose of the study is to identify mutation in exons 22 and 24 of SCN4A gene in Iranian non-dystrophic myotonias patients. METHODS In this study, 28 Iranian patients with non-dystrophic myotonia analyzed for the mutation scanning in exons 22 and 24 of SCN4A gene by polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) and sequencing. RESULTS We found 29073G>C substitution in SCN4A gene in one case and 31506A>G substitution in seven cases. The 29073G>C substitution causes a missense mutation G1306A, located in the conserved cytoplasmic loop connecting repeat III and IV of the SCN4A channel but, 31506A>G substitution do not alter amino acid in SCN4A protein. CONCLUSION G1306A residue is located in functionally important protein region. In "hinged-lid model" for Na(+) channel inactivation in which glycines(1306) act as the hinge of the lid occluding the channel pore. Mutation in this region slowed fast inactivation. Therefore, it might be a pathogenic mutation. The causal relationship of this mutation with the disease is an object for further discussion.
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Affiliation(s)
| | - Mehri Khatami
- Department of Biology, School of Science, Yazd University, Yazd, Iran
| | - Shahriar Nafissi
- Department of Neurology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Afshin Khorrami
- Department of Biology, School of Science, Yazd University, Yazd, Iran
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91
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Fusco C, Frattini D, Salerno GG, Canali E, Bernasconi P, Maggi L. New phenotype and neonatal onset of sodium channel myotonia in a child with a novel mutation of SCN4A gene. Brain Dev 2015; 37:891-3. [PMID: 25735906 DOI: 10.1016/j.braindev.2015.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 01/26/2015] [Accepted: 02/12/2015] [Indexed: 11/15/2022]
Abstract
Myotonia is rare in newborns, and not well-known. Mutations of the skeletal muscle sodium channel gene SCN4A are associated with several neuromuscular disorders including sodium channel myotonias. We reported a 4-year-old female who presented with diffuse stiffness, bilateral clubfoot, hip dislocation, facial dysmorphisms and myotonia at birth. At 4 years of age the neurological examination showed characteristic "Hercules-like appearance" hyporeflexia, mild grip myotonia and bilateral pes cavus. The stiffness was worst at rest and in the early morning which improves with exercise. The clinical features, electromyography findings and diagnostic work-up of this patient and of child's mother were described. The clinical follow-up led us to the diagnosis of sodium channel myotonia with atypical neonatal onset. Mutation analysis in the patient and in child's mother revealed a novel heterozygous p.N1180I mutation in exon 19 of SCN4A gene. We recommend that in newborns with stiffness, peripheral contractures and myotonia, the sequence analysis of SCN4A gene should be performed.
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Affiliation(s)
- Carlo Fusco
- Pediatric Neurology Unit, I.R.C.C.S. Arcispedale Santa Maria Nuova, 42123 Reggio Emilia, Italy.
| | - Daniele Frattini
- Pediatric Neurology Unit, I.R.C.C.S. Arcispedale Santa Maria Nuova, 42123 Reggio Emilia, Italy
| | | | - Elena Canali
- Neurology Unit, I.R.C.C.S. Arcispedale Santa Maria Nuova, 42123 Reggio Emilia, Italy
| | - Pia Bernasconi
- Neurology IV, Neuromuscular Diseases and Neuroimmunology Unit, I.R.C.C.S. Fondazione Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133 Milano, Italy
| | - Lorenzo Maggi
- Neurology IV, Neuromuscular Diseases and Neuroimmunology Unit, I.R.C.C.S. Fondazione Istituto Neurologico "Carlo Besta", Via Celoria 11, 20133 Milano, Italy
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92
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Liu XL, Huang XJ, Shen JY, Zhou HY, Luan XH, Wang T, Chen SD, Wang Y, Tang HD, Cao L. Myotonia congenita: novel mutations in CLCN1 gene. Channels (Austin) 2015; 9:292-8. [PMID: 26260254 DOI: 10.1080/19336950.2015.1075676] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Myotonia congenita belongs to the group of non-dystrophic myotonia caused by mutations of CLCN1gene, which encodes human skeletal muscle chloride channel 1. It can be inherited either in autosomal dominant (Thomsen disease) or recessive (Becker disease) forms. Here we have sequenced all 23 exons and exon-intron boundaries of the CLCN1 gene, in a panel of 5 unrelated Chinese patients with myotonia congenita (2 with dominant and 3 with recessive form). In addition, detailed clinical analysis was performed in these patients to summarize their clinical characteristics in relation to their genotypes. Mutational analyses revealed 7 different point mutations. Of these, we have found 3 novel mutations including 2 missense (R47W, V229M), one splicing (IVS19+2T>C), and 4 known mutations (Y261C,G523D, M560T, G859D). Our data expand the spectrum of CLCN1 mutations and provide insights for genotype-phenotype correlations of myotonia congenita in the Chinese population.
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Affiliation(s)
- Xiao-Li Liu
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Xiao-Jun Huang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Jun-Yi Shen
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Hai-Yan Zhou
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Xing-Hua Luan
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Tian Wang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Sheng-Di Chen
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Ying Wang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Hui-Dong Tang
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
| | - Li Cao
- a Department of Neurology ; Rui Jin Hospital and Rui Jin Hospital North, Shanghai Jiao Tong University School of Medicine ; Shanghai , China
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93
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Imbrici P, Maggi L, Mangiatordi GF, Dinardo MM, Altamura C, Brugnoni R, Alberga D, Pinter GL, Ricci G, Siciliano G, Micheli R, Annicchiarico G, Lattanzi G, Nicolotti O, Morandi L, Bernasconi P, Desaphy JF, Mantegazza R, Camerino DC. ClC-1 mutations in myotonia congenita patients: insights into molecular gating mechanisms and genotype-phenotype correlation. J Physiol 2015; 593:4181-99. [PMID: 26096614 DOI: 10.1113/jp270358] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 06/04/2015] [Indexed: 12/31/2022] Open
Abstract
KEY POINTS Loss-of-function mutations of the skeletal muscle ClC-1 channel cause myotonia congenita with variable phenotypes. Using patch clamp we show that F484L, located in the conducting pore, probably induces mild dominant myotonia by right-shifting the slow gating of ClC-1 channel, without exerting a dominant-negative effect on the wild-type (WT) subunit. Molecular dynamics simulations suggest that F484L affects the slow gate by increasing the frequency and the stability of H-bond formation between E232 in helix F and Y578 in helix R. Three other myotonic ClC-1 mutations are shown to produce distinct effects on channel function: L198P shifts the slow gate to positive potentials, V640G reduces channel activity, while L628P displays a WT-like behaviour (electrophysiology data only). Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function. ABSTRACT Myotonia congenita is an inherited disease caused by loss-of-function mutations of the skeletal muscle ClC-1 chloride channel, characterized by impaired muscle relaxation after contraction and stiffness. In the present study, we provided an in-depth characterization of F484L, a mutation previously identified in dominant myotonia, in order to define the genotype-phenotype correlation, and to elucidate the contribution of this pore residue to the mechanisms of ClC-1 gating. Patch-clamp recordings showed that F484L reduced chloride currents at every tested potential and dramatically right-shifted the voltage dependence of slow gating, thus contributing to the mild clinical phenotype of affected heterozygote carriers. Unlike dominant mutations located at the dimer interface, no dominant-negative effect was observed when F484L mutant subunits were co-expressed with wild type. Molecular dynamics simulations further revealed that F484L affected the slow gate by increasing the frequency and stability of the H-bond formation between the pore residue E232 and the R helix residue Y578. In addition, using patch-clamp electrophysiology, we characterized three other myotonic ClC-1 mutations. We proved that the dominant L198P mutation in the channel pore also right-shifted the voltage dependence of slow gating, recapitulating mild myotonia. The recessive V640G mutant drastically reduced channel function, which probably accounts for myotonia. In contrast, the recessive L628P mutant produced currents very similar to wild type, suggesting that the occurrence of the compound truncating mutation (Q812X) or other muscle-specific mechanisms accounted for the severe symptoms observed in this family. Our results provide novel insight into the molecular mechanisms underlying normal and altered ClC-1 function.
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Affiliation(s)
- P Imbrici
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - L Maggi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - G F Mangiatordi
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - M M Dinardo
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - C Altamura
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - R Brugnoni
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - D Alberga
- Department of Physics 'M. Merlin', INFN and TIRES, University of Bari, Bari, Italy
| | - G Lauria Pinter
- Neuroalgology and Headache Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - G Ricci
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - G Siciliano
- Department of Clinical and Experimental Medicine, Section of Neurology, University of Pisa, Pisa, Italy
| | - R Micheli
- Unit of Child Neurology and Psychiatry, Spedali Civili, Brescia, Italy
| | - G Annicchiarico
- Regional Coordination for Rare Diseases, A. Re. S. Puglia, Bari, Italy
| | - G Lattanzi
- Department of Physics 'M. Merlin', INFN and TIRES, University of Bari, Bari, Italy
| | - O Nicolotti
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - L Morandi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - P Bernasconi
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - J-F Desaphy
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
| | - R Mantegazza
- Neuroimmunology and Neuromuscular Diseases Unit, IRCCS Fondazione Istituto Neurologico 'Carlo Besta', Milano, Italy
| | - D Conte Camerino
- Department of Pharmacy - Drug Sciences, University of Bari, Bari, Italy
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94
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Ørstavik K, Wallace SC, Torbergsen T, Abicht A, Erik Tangsrud S, Kerty E, Rasmussen M. A de novo Mutation in the SCN4A Gene Causing Sodium Channel Myotonia. J Neuromuscul Dis 2015; 2:181-184. [PMID: 27858731 PMCID: PMC5240542 DOI: 10.3233/jnd-150069] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We describe the case of a six year old boy with findings consistent with myotonia congenita: muscular hypertrophy, stiffness when commencing movements and typical warm-up signs. The most prominent symptom was myotonia of the eyelid muscles with apparent swelling around the eyes. Even though the pronounced warm-up phenomena in our patient suggested a chloride channel-associated myotonia congenita, the myotonia of his eyelid muscles indicated an involvement of sodium channels. Screening for mutations in the underlying CLCN1 gene was negative, however, in the SCN4A gene, we identified the missense mutation c.2108T>C; p.Leu703Pro for which there is strong evidence of pathogenicity because it arose de novo in the index patient.
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Affiliation(s)
- Kristin Ørstavik
- Center for Hereditary Muscular Disorders, Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Sean Ciaran Wallace
- Department of Clinical Neurosciences for Children, Oslo University Hospital, Oslo, Norway
| | - Torberg Torbergsen
- Center for Hereditary Muscular Disorders, Department of Neurology, Oslo University Hospital, Oslo, Norway
| | | | | | - Emilia Kerty
- Department of Neurology, Oslo University Hospital, Oslo, Norway
| | - Magnhild Rasmussen
- Center for Hereditary Muscular Disorders, Department of Neurology, Oslo University Hospital, Oslo, Norway.,Department of Clinical Neurosciences for Children, Oslo University Hospital, Oslo, Norway
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95
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Snyder Y, Donlin-Smith C, Snyder E, Pressman E, Ciafaloni E. The course and outcome of pregnancy in women with nondystrophic myotonias. Muscle Nerve 2015; 52:1013-5. [DOI: 10.1002/mus.24684] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2015] [Indexed: 11/11/2022]
Affiliation(s)
- Yuliya Snyder
- Department of Neurology, University of Rochester Medical Center; 607 Elmwood Avenue, Rochester, P.O. Box 673 Rochester New York 14642 USA
| | - Colleen Donlin-Smith
- Department of Neurology, University of Rochester Medical Center; 607 Elmwood Avenue, Rochester, P.O. Box 673 Rochester New York 14642 USA
| | - Eric Snyder
- Department of Neurology, University of Rochester Medical Center; 607 Elmwood Avenue, Rochester, P.O. Box 673 Rochester New York 14642 USA
| | - Eva Pressman
- Department of Obstetrics and Gynecology, University of Rochester Medical Center; 607 Elmwood Avenue, Rochester, P.O. Box 673 Rochester New York 14642 USA
| | - Emma Ciafaloni
- Department of Neurology, University of Rochester Medical Center; 607 Elmwood Avenue, Rochester, P.O. Box 673 Rochester New York 14642 USA
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96
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Yoshinaga H, Sakoda S, Shibata T, Akiyama T, Oka M, Yuan JH, Takashima H, Takahashi MP, Kitamura T, Murakami N, Kobayashi K. Phenotypic variability in childhood of skeletal muscle sodium channelopathies. Pediatr Neurol 2015; 52:504-8. [PMID: 25724373 DOI: 10.1016/j.pediatrneurol.2015.01.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 10/24/2022]
Abstract
BACKGROUND Mutations of the SCN4A gene cause several skeletal muscle channelopathies and overlapping forms of these disorders. However, the variability of the clinical presentation in childhood is confusing and not fully understood among pediatric neurologists. PATIENTS We found three different mutations (p.V445M, p.I693L, and a novel mutation, p.V1149L) in SCN4A but not in the CLCN1 gene. The patient with p.V445M showed the clinical phenotype of sodium channel myotonia, but her clear symptoms did not appear until 11 years of age. Her younger sister and mother, who have the same mutation, displayed marked intrafamilial phenotypic heterogeneity from mild to severe painful myotonia with persistent weakness. The patient with p.I693L exhibited various symptoms that evolved with age, including apneic episodes, tonic muscular contractions during sleep, fluctuating severe episodic myotonia, and finally episodic paralyses. The patient with the novel p.V1149L mutation exhibited episodic paralyses starting at 3 years of age, and myotonic discharges were detected at 11 years of age for the first time. CONCLUSION The present cohort reveals the complexity, variability, and overlapping nature of the clinical features of skeletal muscle sodium channelopathies. These are basically treatable disorders, so it is essential to consider genetic testing before the full development of a patient's condition.
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Affiliation(s)
- Harumi Yoshinaga
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
| | - Shunichi Sakoda
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Takashi Shibata
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Makio Oka
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Jun-Hui Yuan
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan
| | - Masanori P Takahashi
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tetsuro Kitamura
- Department of Pediatrics, Nipponkokan Fukuyama Hospital, Hiroshima, Japan
| | - Nagako Murakami
- Department of Pediatrics, Nipponkokan Fukuyama Hospital, Hiroshima, Japan
| | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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97
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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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98
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Bugiardini E, Rivolta I, Binda A, Soriano Caminero A, Cirillo F, Cinti A, Giovannoni R, Botta A, Cardani R, Wicklund M, Meola G. SCN4A mutation as modifying factor of Myotonic Dystrophy Type 2 phenotype. Neuromuscul Disord 2015; 25:301-7. [DOI: 10.1016/j.nmd.2015.01.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 01/09/2015] [Accepted: 01/14/2015] [Indexed: 12/19/2022]
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99
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Xu C, Qi J, Shi Y, Feng Y, Zang W, Zhang J. Phenotypic variation of Val1589Met mutation in a four-generation Chinese pedigree with mild paramyotonia congenitia: case report. INTERNATIONAL JOURNAL OF CLINICAL AND EXPERIMENTAL PATHOLOGY 2015; 8:1050-1056. [PMID: 25755818 PMCID: PMC4348932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 12/23/2014] [Indexed: 06/04/2023]
Abstract
Four generations of a Chinese family with a mild form of paramyotonia congenital was characterized in phenotype and genotype. For each member, clinical history, physical examination, laboratory tests, electrophysiological and gene analyses were recorded and carried out. A potassium loading, exercise and cold provocation were further tested to diagnose the clinical differentiation. All members shared the characteristics of mild muscle cramp and stiffness induced by exercise or exposed to cold. The symptoms were relieved after rest and warming. A Val1589Met mutation at exon 24 of the SCN4A gene appears in affected subjects, while healthy members had a point mutation at position 1513 at exon 24 of the SCN4A gene. The mild phenotype of the paramyotonia congenital in the family had a Val1589Met mutation in the SCN4A gene. Various phenotypes can exist among different families, indicating that family, individual, genetic or environmental factors influence symptoms.
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Affiliation(s)
- Changshui Xu
- Department of Neurology, People's Hospital of Zhengzhou University Zhengzhou, China
| | - Junjia Qi
- Department of Neurology, People's Hospital of Zhengzhou University Zhengzhou, China
| | - Yingying Shi
- Department of Neurology, People's Hospital of Zhengzhou University Zhengzhou, China
| | - Yan Feng
- Department of Neurology, People's Hospital of Zhengzhou University Zhengzhou, China
| | - Weizhou Zang
- Department of Neurology, People's Hospital of Zhengzhou University Zhengzhou, China
| | - Jiewen Zhang
- Department of Neurology, People's Hospital of Zhengzhou University Zhengzhou, China
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100
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Corrochano S, Männikkö R, Joyce PI, McGoldrick P, Wettstein J, Lassi G, Raja Rayan DL, Blanco G, Quinn C, Liavas A, Lionikas A, Amior N, Dick J, Healy EG, Stewart M, Carter S, Hutchinson M, Bentley L, Fratta P, Cortese A, Cox R, Brown SDM, Tucci V, Wackerhage H, Amato AA, Greensmith L, Koltzenburg M, Hanna MG, Acevedo-Arozena A. Novel mutations in human and mouse SCN4A implicate AMPK in myotonia and periodic paralysis. ACTA ACUST UNITED AC 2014; 137:3171-85. [PMID: 25348630 PMCID: PMC4240299 DOI: 10.1093/brain/awu292] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Mutations in the skeletal muscle channel (SCN4A), encoding the Nav1.4 voltage-gated sodium channel, are causative of a variety of muscle channelopathies, including non-dystrophic myotonias and periodic paralysis. The effects of many of these mutations on channel function have been characterized both in vitro and in vivo. However, little is known about the consequences of SCN4A mutations downstream from their impact on the electrophysiology of the Nav1.4 channel. Here we report the discovery of a novel SCN4A mutation (c.1762A>G; p.I588V) in a patient with myotonia and periodic paralysis, located within the S1 segment of the second domain of the Nav1.4 channel. Using N-ethyl-N-nitrosourea mutagenesis, we generated and characterized a mouse model (named draggen), carrying the equivalent point mutation (c.1744A>G; p.I582V) to that found in the patient with periodic paralysis and myotonia. Draggen mice have myotonia and suffer from intermittent hind-limb immobility attacks. In-depth characterization of draggen mice uncovered novel systemic metabolic abnormalities in Scn4a mouse models and provided novel insights into disease mechanisms. We discovered metabolic alterations leading to lean mice, as well as abnormal AMP-activated protein kinase activation, which were associated with the immobility attacks and may provide a novel potential therapeutic target.
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Affiliation(s)
| | - Roope Männikkö
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | - Peter I Joyce
- 1 MRC Mammalian Genetics Unit, Harwell, Oxfordshire, UK
| | - Philip McGoldrick
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | - Jessica Wettstein
- 3 University of Aberdeen, Institute of Medical Sciences, Scotland, UK
| | - Glenda Lassi
- 4 Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | - Dipa L Raja Rayan
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | | | - Colin Quinn
- 6 Brigham and Women's Hospital, Harvard Medical School, Boston, US
| | - Andrianos Liavas
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | | | - Neta Amior
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | - James Dick
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | - Estelle G Healy
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | | | - Sarah Carter
- 1 MRC Mammalian Genetics Unit, Harwell, Oxfordshire, UK
| | | | - Liz Bentley
- 1 MRC Mammalian Genetics Unit, Harwell, Oxfordshire, UK
| | - Pietro Fratta
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | - Andrea Cortese
- 7 Mondino National Institute of Neurology Foundation, IRCCS, Pavia, Italy
| | - Roger Cox
- 1 MRC Mammalian Genetics Unit, Harwell, Oxfordshire, UK
| | | | - Valter Tucci
- 4 Department of Neuroscience and Brain Technologies, Istituto Italiano di Tecnologia, Genova, Italy
| | | | - Anthony A Amato
- 6 Brigham and Women's Hospital, Harvard Medical School, Boston, US
| | - Linda Greensmith
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | - Martin Koltzenburg
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
| | - Michael G Hanna
- 2 UCL Institute of Neurology, MRC Centre for Neuromuscular Diseases, London, UK
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