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Vicart S, Péréon Y, Ghorab K, Pegat A, Dufresne R, Zozulya-Weidenfeller A, Noury JB, Nadaj-Pakleza A, Tard C, Sacconi S. Self-reported outcomes and quality of life of patients with non-dystrophic myotonia: The French IMPACT 2022 survey. Rev Neurol (Paris) 2024:S0035-3787(24)00530-7. [PMID: 38811249 DOI: 10.1016/j.neurol.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 04/08/2024] [Accepted: 04/21/2024] [Indexed: 05/31/2024]
Abstract
Non-dystrophic myotonias (NDM) are disabling genetic diseases that impact quality of life. To reduce the impact of NDM, patients develop coping strategies such as lifestyle adaptation and avoiding key triggers. To understand how myotonia affects patients' lives, the IMPACT survey, an online questionnaire on patient-reported outcomes, was developed based on international IMPACT questionnaire. The French IMPACT 2022 survey was completed by 47 NDM French patients. Besides muscle stiffness (98%), patients reported muscle pain (83%), falls (70%) and anxiety (77%). These issues negatively impacted abilities to work/study (49%), daily life at home (49%) and overall mobility outside (49%). Most patients (96%) reported ongoing pharmacological treatment (mexiletine, 91%) associated with improvement in muscle stiffness (100%) and reduction in falls (94%), muscle pain (87%) and anxiety (80%). Patients were moderately satisfied (19.1%), satisfied (42.6%) and very satisfied (29.8%) with the current management; 32% rated their quality of life positively (≥ 8 on 10-point scale). In conclusion, this French survey confirms the impact of myotonia on daily life and quality of life. The improvement in patient-reported outcomes in treated participants highlights the importance of managing myotonia with effective treatments. More work should be initiated to assess the importance of NDM symptom management and patients' adherence and compliance to treatment.
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Affiliation(s)
- S Vicart
- National Centre for Muscle Channelopathies, Service of Neuro-Myology, University Hospital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Sorbonne University, INSERM UMR 974, Institute of Myology, 47-83 Boulevard de l'Hôpital 75013 Paris, France.
| | - Y Péréon
- Reference Centre for Neuromuscular Disorders AOC, Euro-NMD, Filnemus, CHU de Nantes, Hôtel-Dieu, 1, place Alexis-Ricordeau, 44000 Nantes, France
| | - K Ghorab
- Reference Centre for Rare Peripheral Neuropathies, CHU de Limoges, 2, avenue Martin-Luther-King, 87000 Limoges, France
| | - A Pegat
- Hospices civils de Lyon, Department of ENMG and Neuromuscular Disorders, Reference Centre of Neuromuscular Disorders, Rhône Alpes, Neurological Hospital P.-Wertheimer, 59, boulevard Pinel, 69500 Bron, France
| | - R Dufresne
- Lupin Neurosciences, Landis+Gyr Strasse 1, 6300 Zug, Switzerland
| | | | - J-B Noury
- Reference Centre for Neuromuscular Disorders AOC, Inserm, LBAI, UMR1227, CHRU de Brest, boulevard Tanguy-Prigent, 29200 Brest, France
| | - A Nadaj-Pakleza
- Reference Centre for Neuromuscular Disorders NEIdF, Euro-NMD, Department of Neurology, Filnemus, hôpitaux universitaires de Strasbourg, 1, avenue Molière, 67200 Strasbourg, France
| | - C Tard
- U1172, Reference Centre for Neuromuscular Disorders Nord/Est/Île-de-France, Department of Neurology, Cognitive-Motor Expertise Unit, CHU de Lille, rue Michel-Polonowski, 59000 Lille, France
| | - S Sacconi
- Reference Centre for Neuromuscular Disorders, CHU de Nice, 30, voie Romaine, 06000 Nice, France
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Jacobsen LN, Stemmerik MG, Skriver SV, Pedersen JJ, Løkken N, Vissing J. Contractile properties and magnetic resonance imaging-assessed fat replacement of muscles in myotonia congenita. Eur J Neurol 2024; 31:e16207. [PMID: 38270354 DOI: 10.1111/ene.16207] [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: 08/14/2023] [Revised: 12/18/2023] [Accepted: 12/28/2023] [Indexed: 01/26/2024]
Abstract
BACKGROUND AND PURPOSE Myotonia congenita (MC) is a muscle channelopathy in which pathogenic variants in a key sarcolemmal chloride channel Gene (CLCN1) cause myotonia. This study used muscle magnetic resonance imaging (MRI) to quantify contractile properties and fat replacement of muscles in a Danish cohort of MC patients. METHODS Individuals with the Thomsen (dominant) and Becker (recessive) variants of MC were studied. Isometric muscle strength, whole-body MRI, and clinical data were collected. The degree of muscle fat replacement of thigh, calf, and forearm muscles was quantitively calculated on Dixon MRI as fat fractions (FFs). Contractility was evaluated as the muscle strength per contractile muscle cross-sectional area (PT/CCSA). Muscle contractility was compared with clinical data. RESULTS Intramuscular FF was increased and contractility reduced in calf and in forearm muscles compared with controls (FF = 7.0-14.3% vs. 5.3-9.6%, PT/CCSA = 1.1-4.9 Nm/cm2 vs. 1.9-5.8 Nm/cm2 [p < 0.05]). Becker individuals also showed increased intramuscular FF and reduced contractility of thigh muscles (FF = 11.9% vs. 9.2%, PT/CCSA = 1.9 Nm/cm2 vs. 3.2 Nm/cm2 [p < 0.05]). Individual muscle analysis showed that increased FF was limited to seven of 18 examined muscles (p < 0.05). There was a weak correlation between reduced contractility and severity of symptoms. CONCLUSIONS Individuals with MC have increased fat replacement and reduced contractile properties of muscles. Nonetheless, changes were small and likely did not impact clinically on their myotonic symptoms.
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Affiliation(s)
- Laura Nørager Jacobsen
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Mads Godtfeldt Stemmerik
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Sofie Vinther Skriver
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jonas Jalili Pedersen
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Nicoline Løkken
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Lloyd A, Rand K, Pike C, Ellis C. Preference-based utility weights for the Individualized Neuromuscular Quality of Life Questionnaire (INQoL), with a focus on non-dystrophic myotonia (NDM). THE EUROPEAN JOURNAL OF HEALTH ECONOMICS : HEPAC : HEALTH ECONOMICS IN PREVENTION AND CARE 2024:10.1007/s10198-024-01674-2. [PMID: 38416296 DOI: 10.1007/s10198-024-01674-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/18/2024] [Indexed: 02/29/2024]
Abstract
INTRODUCTION The Individualized Neuromuscular Quality of Life Questionnaire (INQoL) is used to measure quality of life in neuromuscular disorders such as non-dystrophic myotonia (NDM). Here we report methods to estimate utilities, with a focus on NDM, from this questionnaire based on two preference elicitation exercises. METHODS Eight items from the INQoL were selected with input from three neuromuscular disorder clinical experts with expertise in treating NDM. A discrete choice experiment (DCE) survey of UK general public respondents (n = 508) described outcomes defined by the INQoL items. The same 8 items were also valued using time trade-off (TTO) face-to-face interviews (n = 200). A hybrid regression modelling approach combined both datasets to inform the utility weights. RESULTS Hybrid modelling of DCE and TTO data in conjunction improved out-of-sample predictive accuracy. The selected INQoL utility model indicates substantial disutility associated with all eight dimensions of health, with the greatest losses associated with subjective items such as pain and depression. DISCUSSION The hybrid modelling approach allows us to combine data from the two methodologies and maximize the information from each to inform the utility weights for the INQoL. The TTO is the more conventional valuation method, but combined with the larger DCE study produced better descriptive coverage. This is a relatively novel method for estimating weights which we think is particularly well suited to economic evaluations of orphan drugs.
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Affiliation(s)
| | - Kim Rand
- Health Services Research Unit, Akershus University Hospital, Lørenskog, Norway
- Maths in Health B.V., Klimmen, The Netherlands
| | - Cleo Pike
- Acaster Lloyd Consulting Ltd, London, UK
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Periviita V, Palmio J, Jokela M, Hartikainen P, Vihola A, Rauramaa T, Udd B. CACNA1S Variant Associated With a Myalgic Myopathy Phenotype. Neurology 2023; 101:e1779-e1786. [PMID: 37679049 PMCID: PMC10634652 DOI: 10.1212/wnl.0000000000207639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Accepted: 05/30/2023] [Indexed: 09/09/2023] Open
Abstract
BACKGROUND AND OBJECTIVES This study aimed to characterize the phenotype of a novel myalgic myopathy encountered in a Finnish family. METHODS Four symptomatic and 3 asymptomatic individuals from 2 generations underwent clinical, neurophysiologic, imaging, and muscle biopsy examinations. Targeted sequencing of all known myopathy genes was performed. RESULTS A very rare CACNA1S gene variant c.2893G>C (p.E965Q) was identified in the family. The symptomatic patients presented with exercise-induced myalgia, cramping, muscle stiffness, and fatigue and eventually developed muscle weakness. Examinations revealed mild ptosis and unusual muscle hypertrophy in the upper limbs. In the most advanced disease stage, muscle weakness and muscle atrophy of the limbs were evident. In some patients, muscle biopsy showed mild myopathic findings and creatine kinase levels were slightly elevated. DISCUSSION Myalgia is a very common symptom affecting quality of life. Widespread myalgia may be confused with other myalgic syndromes such as fibromyalgia. In this study, we show that variants in CACNA1S gene may be one cause of severe exercise-induced myalgia.
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Affiliation(s)
- Vesa Periviita
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland.
| | - Johanna Palmio
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Manu Jokela
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Paivi Hartikainen
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Anna Vihola
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Tuomas Rauramaa
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
| | - Bjarne Udd
- From the Department of Neurology (V.P., P.H.), Kuopio University Hospital; Tampere Neuromuscular Center (J.P., M.J., A.V., B.U.); Tampere University Hospital (J.P.); Tampere University (J.P.); Neurology (M.J.), Clinical Medicine, University of Turku; Neurocenter (M.J.), Turku University Hospital; Folkhälsan Research Center (A.V., B.U.), Helsinki; Medicum (A.V., B.U.), University of Helsinki; Fimlab Laboratories (A.V.), Tampere; Department of Pathology (T.R.), Kuopio University Hospital; and Unit of Pathology (T.R.), Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
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Brenes O, Pusch M, Morales F. ClC-1 Chloride Channel: Inputs on the Structure-Function Relationship of Myotonia Congenita-Causing Mutations. Biomedicines 2023; 11:2622. [PMID: 37892996 PMCID: PMC10604815 DOI: 10.3390/biomedicines11102622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 08/11/2023] [Accepted: 08/24/2023] [Indexed: 10/29/2023] Open
Abstract
Myotonia congenita is a hereditary muscle disease mainly characterized by muscle hyperexcitability, which leads to a sustained burst of discharges that correlates with the magnitude and duration of involuntary aftercontractions, muscle stiffness, and hypertrophy. Mutations in the chloride voltage-gated channel 1 (CLCN1) gene that encodes the skeletal muscle chloride channel (ClC-1) are responsible for this disease, which is commonly known as myotonic chloride channelopathy. The biophysical properties of the mutated channel have been explored and analyzed through in vitro approaches, providing important clues to the general function/dysfunction of the wild-type and mutated channels. After an exhaustive search for CLCN1 mutations, we report in this review more than 350 different mutations identified in the literature. We start discussing the physiological role of the ClC-1 channel in skeletal muscle functioning. Then, using the reported functional effects of the naturally occurring mutations, we describe the biophysical and structural characteristics of the ClC-1 channel to update the knowledge of the function of each of the ClC-1 helices, and finally, we attempt to point out some patterns regarding the effects of mutations in the different helices and loops of the protein.
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Affiliation(s)
- Oscar Brenes
- Departamento de Fisiología, Escuela de Medicina, Universidad de Costa Rica, San José 11501-2060, Costa Rica;
- Centro de Investigación en Neurociencias (CIN), Universidad de Costa Rica, San José 11501-2060, Costa Rica
| | - Michael Pusch
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche (CNR), Via De Marini 6, 16149 Genova, Italy
| | - Fernando Morales
- Instituto de Investigaciones en Salud (INISA), Universidad de Costa Rica, San José 11501-2060, Costa Rica
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Vicino A, Brugnoni R, Maggi L. Diagnostics in skeletal muscle channelopathies. Expert Rev Mol Diagn 2023; 23:1175-1193. [PMID: 38009256 DOI: 10.1080/14737159.2023.2288258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/22/2023] [Indexed: 11/28/2023]
Abstract
INTRODUCTION Skeletal muscle channelopathies (SMCs) are a heterogenous group of disorders, caused by mutations in skeletal ion channels leading to abnormal muscle excitability, resulting in either delayed muscle relaxation (myotonia) which characterizes non-dystrophic myotonias (NDMs), or membrane transient inactivation, causing episodic weakness, typical of periodic paralyses (PPs). AREAS COVERED SMCs include myotonia congenita, paramyotonia congenita, and sodium-channel myotonia among NDMs, and hyper-normokalemic, hypokalemic, or late-onset periodic paralyses among PPs. When suspecting an SMC, a structured diagnostic approach is required. Detailed personal and family history and clinical examination are essential, while neurophysiological tests should confirm myotonia and rule out alternative diagnosis. Moreover, specific electrodiagnostic studies are important to further define the phenotype of de novo cases and drive molecular analyses together with clinical data. Definite diagnosis is achieved through genetic testing, either with Sanger sequencing or multigene next-generation sequencing panel. In still unsolved patients, more advanced techniques, as exome-variant sequencing or whole-genome sequencing, may be considered in expert centers. EXPERT OPINION The diagnostic approach to SMC is still mainly based on clinical data; moreover, definite diagnosis is sometimes complicated by the difficulty to establish a proper genotype-phenotype correlation. Lastly, further studies are needed to allow the genetic characterization of unsolved patients.
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Affiliation(s)
- Alex Vicino
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
- Nerve-Muscle Unit, Neurology Service, Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Raffaella Brugnoni
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Lorenzo Maggi
- Neurology IV Unit, Neuroimmunology and Neuromuscular Diseases, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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Chapman AM, Schurer M, Weijers L, Omar A, Lee H, Weidenfeller AZ, Ellis C, Sonecha S, Schneider-Gold C. Improving the understanding of how patients with non-dystrophic myotonia are selected for myotonia treatment with mexiletine (NaMuscla): outcomes of treatment impact using a European Delphi panel. BMC Neurol 2021; 21:467. [PMID: 34852780 PMCID: PMC8633892 DOI: 10.1186/s12883-021-02491-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 11/10/2021] [Indexed: 11/17/2022] Open
Abstract
Background Non-dystrophic myotonias (NDMs) comprise muscle chloride and sodium channelopathies due to genetic defects of the CLCN1- and SCN4A-channels. No licensed antimyotonic treatment has been available until approval of mexiletine (NaMuscla®) for adult patients by the EMA in December 2018. This Delphi panel aimed to understand how outcomes of the pivotal phase III Mexiletine study (MYOMEX) translate to real world practice and investigate health resource use, quality of life and the natural history of NDM to support economic modelling and facilitate patient access. Methods Nine clinical experts in treating NDM took part in a two-round Delphi panel. Their knowledge of NDM and previous use of mexiletine as an off-label treatment prior to NaMuscla’s approval ensured they could provide both qualitative context and quantitative estimates to support economic modelling comparing mexiletine (NaMuscla) to best supportive care. Consensus in four key areas was sought: healthcare resource utilization (HRU), treatment with mexiletine (NaMuscla), patient quality of life (QoL), and the natural history of disease. Concept questions were also asked, considering perceptions on the feasibility of mapping the validated Individualized Neuromuscular Quality of Life (INQoL) instrument to the generic EQ-5D™, and the potential impact on caregiver QoL. Results Consensus was achieved for key questions including the average long-term dosage of mexiletine (NaMuscla) in practice, the criteria for eligibility of myotonia treatment, the clinical importance of QoL outcomes in MYOMEX, the higher proportion of patients with increased QoL, and the reduction in the need for mental health resources for patients receiving mexiletine (NaMuscla). While consensus was not achieved for other questions, the results demonstrated that most experts felt mexiletine (NaMuscla) reduced the need for HRU and was expected to improve QoL. The QoL mapping exercise suggested that it is feasible to map domains of INQoL to EQ-5D. Points of interest for future research were identified, including that mexiletine (NaMuscla) may slow the annual decrease in QoL of patients over their lifetime, and a significant negative impact on QoL for some caregivers. Conclusions This project successfully provided data from an informed group of clinical experts, complementing the currently available clinical trial data for mexiletine (NaMuscla) to support patient access decisions. Supplementary Information The online version contains supplementary material available at 10.1186/s12883-021-02491-3.
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Affiliation(s)
| | | | | | - Amer Omar
- Lupin Atlantis Holdings SA, Zug, Switzerland
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Vicart S, Franques J, Bouhour F, Magot A, Péréon Y, Sacconi S, Nadaj-Pakleza A, Behin A, Zahr N, Hézode M, Fournier E, Payan C, Lacomblez L, Fontaine B. Efficacy and safety of mexiletine in non-dystrophic myotonias: A randomised, double-blind, placebo-controlled, cross-over study. Neuromuscul Disord 2021; 31:1124-1135. [PMID: 34702654 DOI: 10.1016/j.nmd.2021.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/11/2021] [Accepted: 06/22/2021] [Indexed: 11/30/2022]
Abstract
The MYOMEX study was a multicentre, randomised, double-blind, placebo-controlled, cross-over study aimed to compare the effects of mexiletine vs. placebo in patients with myotonia congenita (MC) and paramyotonia congenita (PC). The primary endpoint was the self-reported score of stiffness severity on a 100 mm visual analogic scale (VAS). Mexiletine treatment started at 200 mg/day and was up-titrated by 200 mg increment each three days to reach a maximum dose of 600 mg/day for total treatment duration of 18 days for each cross-over period. The modified intent-to-treat population included 25 patients (13 with MC and 12 with PC; mean age, 43.0 years; male, 68.0%). The median VAS score for mexiletine was 71.0 at baseline and decreased to 16.0 at the end of the treatment while the score did not change for placebo (81.0 at baseline vs. 78.0 at end of treatment). A mixed effects linear model analysis on ranked absolute changes showed a significant effect of treatment (p < 0.001). The overall score of the Individualized Neuromuscular Quality of Life questionnaire (INQoL) was significantly improved (p < 0.001). No clinically significant adverse events were reported. In conclusion, mexiletine improved stiffness and quality of life in patients with nondystrophic myotonia and was well tolerated.
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Affiliation(s)
- Savine Vicart
- Assistance Publique-Hôpitaux de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology, Muscle Channelopathies Reference Center and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France.
| | - Jérôme Franques
- Assistance Publique-Hôpitaux de Marseille, Department of Neurology and Neuromuscular Diseases, La Timone Hospital, Marseille, France
| | - Françoise Bouhour
- Electroneuromyography and Neuromuscular Disorders Department, Hospices Civils de Lyon, University Hospital of Lyon, France
| | - Armelle Magot
- Reference Centre for Neuromuscular disorders AOC, University Hospital, Hôtel-Dieu, Nantes, France
| | - Yann Péréon
- Reference Centre for Neuromuscular disorders AOC, University Hospital, Hôtel-Dieu, Nantes, France
| | - Sabrina Sacconi
- Université Côte d'Azur, Peripheral Nervous System & Muscle Department, Pasteur 2 Hospital, Centre Hospitalier Universitaire de Nice, Nice, France
| | - Aleksandra Nadaj-Pakleza
- Reference Centre for Neuromuscular disorders AOC, Neurology Department, University Hospital of Angers, Angers, France
| | - Anthony Behin
- Assistance Publique-Hôpitaux de Paris, Service of Neuro-Myology, Reference Centre for Neuromuscular disorders NEIdF, University Hospital Pitié-Salpêtrière, Paris, France
| | - Noël Zahr
- Assistance Publique-Hôpitaux de Paris, Sorbonne Université, Pharmacology Department, University Hospital Pitié-Salpêtrière, Paris, France
| | - Marianne Hézode
- Assistance Publique-Hôpitaux de Paris, Sorbonne Université, Department of Clinical Neurophysiology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Emmanuel Fournier
- Assistance Publique-Hôpitaux de Paris, Sorbonne Université, Department of Clinical Neurophysiology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Christine Payan
- Assistance Publique-Hôpitaux de Paris, Sorbonne Université, Pharmacology Department, University Hospital Pitié-Salpêtrière, Paris, France
| | - Lucette Lacomblez
- Assistance Publique-Hôpitaux de Paris, Sorbonne Université, Pharmacology Department, University Hospital Pitié-Salpêtrière, Paris, France; Assistance Publique-Hôpitaux de Paris, Sorbonne Université, INSERM U 1422, Neurology Department, University Hospital Pitié-Salpêtrière, Paris, France
| | - Bertrand Fontaine
- Assistance Publique-Hôpitaux de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology, Muscle Channelopathies Reference Center and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
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Matthews E, Holmes S, Fialho D. Skeletal muscle channelopathies: a guide to diagnosis and management. Pract Neurol 2021; 21:196-204. [PMID: 33563766 DOI: 10.1136/practneurol-2020-002576] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2020] [Indexed: 12/17/2022]
Abstract
Skeletal muscle channelopathies are a group of rare episodic genetic disorders comprising the periodic paralyses and the non-dystrophic myotonias. They may cause significant morbidity, limit vocational opportunities, be socially embarrassing, and sometimes are associated with sudden cardiac death. The diagnosis is often hampered by symptoms that patients may find difficult to describe, a normal examination in the absence of symptoms, and the need to interpret numerous tests that may be normal or abnormal. However, the symptoms respond very well to holistic management and pharmacological treatment, with great benefit to quality of life. Here, we review when to suspect a muscle channelopathy, how to investigate a possible case and the options for therapy once a diagnosis is made.
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Affiliation(s)
- Emma Matthews
- Atkinson-Morley Neuromuscular Centre, St George's University Hospitals NHS Foundation Trust, London, UK
- Department of Neuromuscular Diseases, UCL, Institute of Neurology, London, UK
| | - Sarah Holmes
- Queen Square Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, UK
| | - Doreen Fialho
- Department of Neuromuscular Diseases, UCL, Institute of Neurology, London, UK
- Queen Square Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, UK
- Department of Clinical Neurophysiology, King's College Hospital NHS Foundation Trust, London, UK
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Non-dystrophic myotonias: clinical and mutation spectrum of 70 German patients. J Neurol 2020; 268:1708-1720. [PMID: 33263785 PMCID: PMC8068660 DOI: 10.1007/s00415-020-10328-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 11/09/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022]
Abstract
Introduction Non-dystrophic myotonias (NDM) are heterogeneous diseases caused by mutations in CLCN1 and SCN4A. The study aimed to describe the clinical and genetic spectrum of NDM in a large German cohort. Methods We retrospectively identified all patients with genetically confirmed NDM diagnosed in our center. The following data were analyzed: demographics, family history, muscular features, cardiac involvement, CK, EMG, genotype, other tested genes, treatment perceived efficacy. Results 70 patients (age 40.2 years ± 14.9; 52.8% males) were included in our study (48 NDM-CLCN1, 22 NDM-SCN4A). The most frequent presenting symptoms were myotonia (NDM-CLCN1 83.3%, NDM-SCN4A 72.2%) and myalgia (NDM-CLCN1 57.4%, NDM-SCN4A 52.6%). Besides a more prominent facial involvement in NDM-SCN4A and cold-sensitivity in NDM-CLCN1, no other significant differences were observed between groups. Cardiac arrhythmia or conduction defects were documented in sixNDM-CLCN1 patients (three of them requiring a pacemaker) and one patient with NDM-SCN4A. CK was normal in 40% of patients. Myotonic runs in EMG were detected in 89.1% of CLCN1 and 78.9% of SCN4A. 50% of NDM-CLCN1 patients had the classic c.2680C>T (p.Arg894*) mutation. 12 new genetic variants are reported. About 50% of patients were not taking any anti-myotonic drug at the last follow-up. The anti-myotonic drugs with the best patient’s perceived efficacy were mexiletine and lamotrigine. Conclusion This study highlights the relevant clinical overlap between NDM-CLCN1 and NDM-SCN4A patients and warrants the use of early and broad genetic investigation for the precise identification of the NDM subtype. Besides the clinical and genetic heterogeneity, the limited response to current anti-myotonic drugs constitutes a continuing challenge. Supplementary Information The online version contains supplementary material available at 10.1007/s00415-020-10328-1.
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Stunnenberg BC, LoRusso S, Arnold WD, Barohn RJ, Cannon SC, Fontaine B, Griggs RC, Hanna MG, Matthews E, Meola G, Sansone VA, Trivedi JR, van Engelen BG, Vicart S, Statland JM. Guidelines on clinical presentation and management of nondystrophic myotonias. Muscle Nerve 2020; 62:430-444. [PMID: 32270509 PMCID: PMC8117169 DOI: 10.1002/mus.26887] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 04/01/2020] [Accepted: 04/04/2020] [Indexed: 12/26/2022]
Abstract
The nondystrophic myotonias are rare muscle hyperexcitability disorders caused by gain-of-function mutations in the SCN4A gene or loss-of-function mutations in the CLCN1 gene. Clinically, they are characterized by myotonia, defined as delayed muscle relaxation after voluntary contraction, which leads to symptoms of muscle stiffness, pain, fatigue, and weakness. Diagnosis is based on history and examination findings, the presence of electrical myotonia on electromyography, and genetic confirmation. In the absence of genetic confirmation, the diagnosis is supported by detailed electrophysiological testing, exclusion of other related disorders, and analysis of a variant of uncertain significance if present. Symptomatic treatment with a sodium channel blocker, such as mexiletine, is usually the first step in management, as well as educating patients about potential anesthetic complications.
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Affiliation(s)
- Bas C. Stunnenberg
- Department of Neurology, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Samantha LoRusso
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - W. David Arnold
- Department of Neurology, Ohio State University Wexner Medical Center, Columbus, Ohio
| | - Richard J. Barohn
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
| | - Stephen C. Cannon
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Bertrand Fontaine
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Robert C. Griggs
- Department of Neurology, University of Rochester, Rochester, New York
| | - Michael G. Hanna
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, Department of Neuromuscular diseases, UCL Queen Square Institute of Neurology, United Kingdom
| | - Giovanni Meola
- Department of Neurorehabilitation Sciences, Casa Cura Policlinico, Milan, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Valeria A. Sansone
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
- Neurorehabilitation Unit, University of Milan, NEuroMuscular Omnicentre (NEMO), Fondazione Serena Onlus, Milan, Italy
| | - Jaya R. Trivedi
- Department of Neurology and Neurotherapeutics, UT Southwestern Medical Center, Dallas, Texas
| | | | - Savine Vicart
- Assistance Publique-Hôpitaix de Paris, Sorbonne Université, INSERM, Service of Neuro-Myology and UMR 974, Institute of Myology, University Hospital Pitié-Salpêtrière, Paris, France
| | - Jeffrey M. Statland
- Department of Neurology, University of Kansas Medical Center, Kansas City, Kansas
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Avila-Smirnow D, Vargas Leal CP, Beytía Reyes MDLA, Cortés Zepeda R, Escobar RG, Kleinsteuber Saa K, Lagos Lucero M, Avaria Benapres MDLA, Padilla Pérez O, Casar Leturia JC, Mellado Sagredo C, Sternberg D. Non-dystrophic myotonia Chilean cohort with predominance of the SCN4A Gly1306Glu variant. Neuromuscul Disord 2020; 30:554-561. [DOI: 10.1016/j.nmd.2020.04.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/03/2020] [Accepted: 04/23/2020] [Indexed: 01/31/2023]
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Suetterlin KJ, Raja Rayan D, Matthews E, Hanna MG. Mexiletine (NaMuscla) for the treatment of myotonia in non-dystrophic myotonic disorders. Expert Opin Orphan Drugs 2020. [DOI: 10.1080/21678707.2020.1739519] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Karen J. Suetterlin
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Dipa Raja Rayan
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Emma Matthews
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Michael G Hanna
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
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The Fatigue Assessment Scale: quality and availability in sarcoidosis and other diseases. Curr Opin Pulm Med 2019; 24:495-503. [PMID: 29889115 DOI: 10.1097/mcp.0000000000000496] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE OF REVIEW Fatigue is a problem experienced by many patients suffering from chronic diseases, including sarcoidosis patients. It has a substantial influence on patients' quality of life (QoL). It is, therefore, important to properly assess fatigue with a valid and reliable measure. The Fatigue Assessment Scale (FAS) is the only validated self-reporting instrument classifying fatigue in sarcoidosis. The aim of this review was to examine the psychometric properties of the FAS and the diseases and languages in which it has been used. Studies among sarcoidosis patients were also reviewed in terms of outcomes. RECENT FINDINGS Studies were identified by searching the electronic bibliographic database Pubmed. Search terms used were: FAS and fatigue. Articles were included in the review if the FAS had been used to assess fatigue. RESULTS Since its introduction, the FAS was used in 26 different diseases or conditions, including stroke, neurologic disorders, rheumatoid arthritis, idiopathic pulmonary fibrosis and sarcoidosis. Its reliability and validity have proved to be good. Unidimensionality has been established. So far, the FAS is available in 20 languages and widely used in sarcoidosis. Digital versions as well as PDFs of various languages are available online (www.wasog.org). SUMMARY The FAS has good psychometric qualities for the diseases in which it has been examined, including sarcoidosis, and can be used in clinical practice. Healthcare workers can use the FAS to assess fatigue in the management, follow-up and clinical care programmes for their patients consistently across countries, as well as in clinical research.
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Torbergsen T, Jurkat-Rott K, Stålberg EV, Løseth S, Hødneø A, Lehmann-Horn F. Painful cramps and giant myotonic discharges in a family with the Nav1.4-G1306A mutation. Muscle Nerve 2015; 52:680-3. [PMID: 26080010 DOI: 10.1002/mus.24672] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2015] [Indexed: 11/10/2022]
Abstract
INTRODUCTION Two previously reported Norwegian patients with painful muscle cramps and giant myotonic discharges were genotyped and compared with those of members of 21 families harboring the same mutation. METHODS Using primers specific for SCN4A and CLCN1, the DNA of the Norwegian family members was amplified and bidirectionally sequenced. Clinical and neurophysiological features of other families harboring the same mutation were studied. RESULTS A G1306A mutation in the Nav1.4 voltage-gated sodium channel of skeletal muscle was identified. This mutation is known to cause myotonia fluctuans. No giant myotonic discharges or painful muscle cramps were found in the other G1306A families. CONCLUSIONS Ephaptic transmission between neighboring muscle fibers may not only cause the unusual size of the myotonic discharges in this family, but also a more severe type of potassium-aggravated myotonia than myotonia fluctuans.
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Affiliation(s)
- Torberg Torbergsen
- Department of Clinical Neurophysiology, University Hospital of North Norway, Tromsö, Norway
| | - Karin Jurkat-Rott
- Division of Neurophysiology and Neuromuscular Center, University of Ulm, Ulm, Germany
| | - Erik V Stålberg
- Department of Clinical Neurophysiology, Institute of Neurosciences, Uppsala University, Uppsala, Sweden
| | - Sissel Løseth
- Department of Clinical Neurophysiology, University Hospital of North Norway, Tromsö, Norway
| | - Anne Hødneø
- Department of Neurology, Vestfold County Hospital, Tønsberg, Norway
| | - Frank Lehmann-Horn
- Division of Neurophysiology and Neuromuscular Center, University of Ulm, Ulm, Germany
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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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Stunnenberg BC, Woertman W, Raaphorst J, Statland JM, Griggs RC, Timmermans J, Saris CG, Schouwenberg BJ, Groenewoud HM, Stegeman DF, van Engelen BGM, Drost G, van der Wilt GJ. Combined N-of-1 trials to investigate mexiletine in non-dystrophic myotonia using a Bayesian approach; study rationale and protocol. BMC Neurol 2015; 15:43. [PMID: 25880166 PMCID: PMC4407841 DOI: 10.1186/s12883-015-0294-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 02/27/2015] [Indexed: 01/22/2023] Open
Abstract
Background To obtain evidence for the clinical and cost-effectiveness of treatments for patients with rare diseases is a challenge. Non-dystrophic myotonia (NDM) is a group of inherited, rare muscle diseases characterized by muscle stiffness. The reimbursement of mexiletine, the expert opinion drug for NDM, has been discontinued in some countries due to a lack of independent randomized controlled trials (RCTs). It remains unclear however, which concessions can be accepted towards the level 1 evidence needed for coverage decisions, in rare diseases. Considering the large number of rare diseases with a lack of treatment evidence, more experience with innovative trial designs is needed. Both NDM and mexiletine are well suited for an N-of-1 trial design. A Bayesian approach allows for the combination of N-of-1 trials, which enables the assessment of outcomes on the patient and group level simultaneously. Methods/Design We will combine 30 individual, double-blind, randomized, placebo-controlled N-of-1 trials of mexiletine (600 mg daily) vs. placebo in genetically confirmed NDM patients using hierarchical Bayesian modeling. Our results will be compared and combined with the main results of an international cross-over RCT (mexiletine vs. placebo in NDM) published in 2012 that will be used as an informative prior. Similar criteria of eligibility, treatment regimen, end-points and measurement instruments are employed as used in the international cross-over RCT. Discussion The treatment of patients with NDM with mexiletine offers a unique opportunity to compare outcomes and efficiency of novel N-of-1 trial-based designs and conventional approaches in producing evidence of clinical and cost-effectiveness of treatments for patients with rare diseases. Trial registration ClinicalTrials.gov Identifier: NCT02045667
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Affiliation(s)
- Bas C Stunnenberg
- Department of Neurology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Willem Woertman
- Department of Health Evidence, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Joost Raaphorst
- Department of Neurology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Jeffrey M Statland
- Department of Neurology, University of Kansas Medical Center, PO Box 2012, KS 66160, Kansas City, USA.
| | - Robert C Griggs
- Department of Neurology, University of Rochester Medical Center, PO Box 420669, Rochester, NY, 14642, USA.
| | - Janneke Timmermans
- Department of Cardiology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Christiaan G Saris
- Department of Neurology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Bas J Schouwenberg
- Department of Pharmacology-Toxicology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Hans M Groenewoud
- Department of Health Evidence, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Dick F Stegeman
- Department of Neurology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Baziel G M van Engelen
- Department of Neurology, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Gea Drost
- Department of Neurology and Neurosurgery, University Medical Center Groningen, PO Box 30001, 9700 RB, Groningen, The Netherlands.
| | - Gert Jan van der Wilt
- Department of Health Evidence, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Dramatic improvement of myotonia permanens with flecainide: a two-case report of a possible bench-to-bedside pharmacogenetics strategy. Eur J Clin Pharmacol 2012; 69:1037-9. [PMID: 23052413 PMCID: PMC3621996 DOI: 10.1007/s00228-012-1414-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2012] [Accepted: 09/17/2012] [Indexed: 11/02/2022]
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Sansone VA, Ricci C, Montanari M, Apolone G, Rose M, Meola G. Measuring quality of life impairment in skeletal muscle channelopathies. Eur J Neurol 2012; 19:1470-6. [PMID: 22607270 PMCID: PMC3492909 DOI: 10.1111/j.1468-1331.2012.03751.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 04/02/2012] [Indexed: 01/31/2023]
Abstract
Background and purpose Fatigue and pain have been previously shown to be important determinants for decreasing quality of life (QoL) in one report in patients with non-dystrophic myotonia. The aims of our study were to assess QoL in skeletal muscle channelopathies (SMC) using INQoL (individualized QoL) and SF-36 questionnaires. Methods We administered INQoL and SF-36 to 66 Italian patients with SMC (26: periodic paralysis, 36: myotonia congenita and 4: Andersen-Tawil) and compared the results in 422 patients with myotonic dystrophies (DM1: 382; and DM2: 40). Results (i) INQoL index in SMC is similar to that in DMs (P = 0.79). (ii) Patients with myotonia congenita have the worst perception of QoL. (iii) Myotonia has the most detrimental effect on patients with myotonia congenita, followed by patients with DM2 and then by patients with DM1 and hyperkalemic periodic paralysis. (iv) Pain is a significant complaint in patients with myotonia congenita, hypokalemic periodic paralysis and DM2 but not in DM1. (v) Fatigue has a similar detrimental effect on all patient groups except for patients with hyperkalemic periodic paralysis in whom muscle weakness and myotonia more than fatigue affect QoL perception. (vi) Muscle symptoms considered in INQoL correlate with physical symptoms assessed by SF-36 (R from −0.34 to −0.76). Conclusions QoL perception in patients with SMC is similar to that of patients with DMs, chronic multisystem disabling conditions. Our results provide information to target treatment and health care of these patients. The sensitivity of INQoL to changes in QoL in the SMC needs to be further explored in longitudinal studies.
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Affiliation(s)
- V A Sansone
- Department of Neurology, University of Milan, IRCCS Policlinico San Donato, Milan, Italy.
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Tieleman AA, Jenks KM, Kalkman JS, Borm G, van Engelen BGM. High disease impact of myotonic dystrophy type 2 on physical and mental functioning. J Neurol 2011; 258:1820-6. [PMID: 21461958 PMCID: PMC3184219 DOI: 10.1007/s00415-011-6027-8] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2010] [Revised: 03/20/2011] [Accepted: 03/23/2011] [Indexed: 11/25/2022]
Abstract
The aim of the study was to investigate health status in patients with myotonic dystrophy type 2 (DM2) and determine its relationship to pain and fatigue. Data on health status (SF-36), pain (MPQ) and fatigue (CIS-fatigue) were collected for the Dutch DM2 population (n = 32). Results were compared with those of sex- and age-matched adult-onset myotonic dystrophy type 1 (DM1) patients. In addition, we compared the obtained scores on health status of the DM2 group with normative data of the Dutch general population (n = 1742). Compared to DM1, the SF-36 score for bodily pain was significantly (p = 0.04) lower in DM2, indicating more body pain in DM2. DM2 did not differ from DM1 on any other SF-36 scales. In comparison to the Dutch population, DM2 patients reported lower scores (indicating worse clinical condition) on the physical functioning, role functioning-physical, bodily pain, general health, vitality, social functioning, and role functioning-emotional scales (p < 0.01 on all scales). The difference was most profound for the physical functioning scale. In the DM2 group the severity of pain was significantly correlated with SF-36 scores for bodily pain (p = 0.003). Fatigue was significantly correlated with the SF-36 scores for role functioning-physical (p = 0.001), general health (p = 0.02), and vitality (p = 0.02). The impact of DM2 on a patients' physical, psychological and social functioning is significant and as high as in adult-onset DM1 patients. From the perspective of health-related quality of life, DM2 should not be considered a benign disease. Management of DM2 patients should include screening for pain and fatigue. Symptomatic treatment of pain and fatigue may decrease disease impact and help improve health status in DM2, even if the disease itself cannot be treated.
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Affiliation(s)
- Alide A Tieleman
- Department of Neurology, Neuromuscular Centre Nijmegen, Radboud University Nijmegen Medical Centre, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Matthews E, Fialho D, Tan SV, Venance SL, Cannon SC, Sternberg D, Fontaine B, Amato AA, Barohn RJ, Griggs RC, Hanna MG. The non-dystrophic myotonias: molecular pathogenesis, diagnosis and treatment. ACTA ACUST UNITED AC 2009; 133:9-22. [PMID: 19917643 DOI: 10.1093/brain/awp294] [Citation(s) in RCA: 142] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The non-dystrophic myotonias are an important group of skeletal muscle channelopathies electrophysiologically characterized by altered membrane excitability. Many distinct clinical phenotypes are now recognized and range in severity from severe neonatal myotonia with respiratory compromise through to milder late-onset myotonic muscle stiffness. Specific genetic mutations in the major skeletal muscle voltage gated chloride channel gene and in the voltage gated sodium channel gene are causative in most patients. Recent work has allowed more precise correlations between the genotype and the electrophysiological and clinical phenotype. The majority of patients with myotonia have either a primary or secondary loss of membrane chloride conductance predicted to result in reduction of the resting membrane potential. Causative mutations in the sodium channel gene result in an abnormal gain of sodium channel function that may show marked temperature dependence. Despite significant advances in the clinical, genetic and molecular pathophysiological understanding of these disorders, which we review here, there are important unresolved issues we address: (i) recent work suggests that specialized clinical neurophysiology can identify channel specific patterns and aid genetic diagnosis in many cases however, it is not yet clear if such techniques can be refined to predict the causative gene in all cases or even predict the precise genotype; (ii) although clinical experience indicates these patients can have significant progressive morbidity, the detailed natural history and determinants of morbidity have not been specifically studied in a prospective fashion; (iii) some patients develop myopathy, but its frequency, severity and possible response to treatment remains undetermined, furthermore, the pathophysiogical link between ion channel dysfunction and muscle degeneration is unknown; (iv) there is currently insufficient clinical trial evidence to recommend a standard treatment. Limited data suggest that sodium channel blocking agents have some efficacy. However, establishing the effectiveness of a therapy requires completion of multi-centre randomized controlled trials employing accurate outcome measures including reliable quantitation of myotonia. More specific pharmacological approaches are required and could include those which might preferentially reduce persistent muscle sodium currents or enhance the conductance of mutant chloride channels. Alternative strategies may be directed at preventing premature mutant channel degradation or correcting the mis-targeting of the mutant channels.
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Affiliation(s)
- E Matthews
- MRC Centre for Neuromuscular Diseases, UCL, Institute of Neurology, Queen Square, London, WC1N 3BG, England
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