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Valeria A Sansone
PURPOSE OF REVIEW: This article describes clinical and electrical myotonia and provides an update on the classification, diagnosis, and management of myotonic disorders. RECENT FINDINGS: In the myotonic dystrophies, antisense oligonucleotides provide a general strategy to correct RNA gain of function and modulate the expression of CTG expanded repeats; they are currently being tested in a phase 1-2 randomized controlled trial in patients with adult-onset myotonic dystrophy type 1...
December 2016: Continuum: Lifelong Learning in Neurology
İpek Polat, Pakize Karaoğlu, Uluç Yiş, Semra Hız Kurul
Schwartz-Jampel syndrome is a rare autosomal recessive disorder with joint contractures, generalized myotonia, skeletal anomalies, and facial dysmorphism. The patients with Schwartz-Jampel syndrome have muscle stiffness and electromyography reveals complex, repetitive discharges as myotonic discharges. It is unusual for a Schwartz-Jampel syndrome case to have recurrent gastrointestinal bleeding episodes. The stable endothelial barrier is provided by perlecan which is an important component of vascular structures...
July 2016: Journal of Pediatric Neurosciences
Cheryl A Smith, Laurie Gutmann
Myotonic dystrophy (DM1) is the most common form of adult muscular dystrophy. It is a multisystem disorder with a complex pathophysiology. Although inheritance is autosomal dominant, disease variability is attributed to anticipation, a maternal expansion bias, variable penetrance, somatic mosaicism, and a multitude of aberrant pre-mRNA splicing events. Patient presentations range from asymptomatic or mild late onset adult to severe congenital forms. Multiple organ systems may be affected. Patients may experience early cataracts, myotonia, muscle weakness/atrophy, fatigue, excessive daytime sleepiness, central/obstructive apnea, respiratory failure, cardiac arrhythmia, insulin resistance, dysphagia, GI dysmotility, cognitive impairment, Cluster C personality traits, and/or mood disorders...
December 2016: Current Treatment Options in Neurology
Martin Skov, Frank V de Paoli, Ole B Nielsen, Thomas H Pedersen
INTRODUCTION: In myotonia congenita, loss of ClC-1 Cl(-) -channel function results in skeletal muscle hyperexcitability and myotonia. Anti-myotonic treatment has typically targeted the voltage gated sodium channel in skeletal muscle (Nav1.4). This study explored whether 3 sodium channel modulating anti-epileptics can reduce myotonia in isolated rat and human muscle. METHODS: Dissected muscles were rendered myotonic by ClC-1 channel inhibition. The ability of the drugs to suppress myotonia was then assessed from sub-clinical to maximal clinical concentrations...
October 26, 2016: Muscle & Nerve
Eman M Khedr, Gharib Fawi, Mohammed Abd-Allah Abbas, Noha Abo El-Fetoh, Ahmed F Zaki, Ayman Gamea, Ghada Al Attar
BACKGROUND: Few epidemiological studies of the prevalence of neuromuscular disorders have been undertaken. The aim of the study was to estimate the prevalence of the most common types of neuromuscular disorders in Qena governorate/Egypt. METHODS: A random sample was taken from 11 districts, involving 9303 inhabitants with 57.3% urban residents and 42.7% rural residence. Patients were diagnosed using a screening questionnaire for the diagnosis of neuromuscular disorders...
October 17, 2016: Neurological Research
Michela De Bellis, Roberta Carbonara, Julien Roussel, Alessandro Farinato, Ada Massari, Sabata Pierno, Marilena Muraglia, Filomena Corbo, Carlo Franchini, Maria Rosaria Carratù, Annamaria De Luca, Diana Conte Camerino, Jean-François Desaphy
Although the sodium channel blocker, mexiletine, is the first choice drug in myotonia, some myotonic patients remain unsatisfied due to contraindications, lack of tolerability, or incomplete response. More therapeutic options are thus needed for myotonic patients, which require clinical trials based on solid preclinical data. In previous structure-activity relationship studies, we identified two newly-synthesized derivatives of tocainide, To040 and To042, with greatly enhanced potency and use-dependent behavior in inhibiting sodium currents in frog skeletal muscle fibers...
October 13, 2016: Neuropharmacology
Chunxiang Fan, Ninghui Mao, Frank Lehmann-Horn, Jan Bürmann, Karin Jurkat-Rott
Hyperkalemic periodic paralysis (HyperPP) is a dominantly inherited muscle disease caused by mutations in SCN4A gene encoding skeletal muscle voltage gated Nav 1.4 channels. We identified a novel Nav 1.4 mutation I692M in 14 families out of the 104 genetically identified HyperPP families in the Neuromuscular Centre Ulm and is therefore as frequent as I693T (13 families out of 14 HyperPP families) in Germany. Surprisingly, in 13 families, a known polymorphism S906T was also present. It was on the affected allele in at least 10 families compatible with a possible founder effect in central Europe...
October 6, 2016: Clinical Genetics
Yukiko Mori, Satoshi Yamashita, Mai Kato, Teruaki Masuda, Koutaro Takamatsu, Toshihide Kumamoto, Ryogen Sasaki, Yukio Ando
Myotonia congenita is a non-dystrophic skeletal muscle disorder characterized by muscle stiffness and an inability of the muscle to relax after voluntary contraction caused by a mutation in the gene encoding skeletal muscle chloride channel-1 (CLCN1). We encountered a case of Thomsen disease with ptosis. A short tau inversion recovery MR imaging demonstrated high-intensity lesions in the levator palpebrae superioris muscles. Molecular genetic testing revealed a heterozygosity for the c.1439C>A (p.P480H) mutation in the CLCN1 gene...
September 3, 2016: Neuromuscular Disorders: NMD
Mohammad Rohani, Shahnaz Miri, Alireza Rezai-Ashtiani
No abstract text is available yet for this article.
July 6, 2016: Iranian Journal of Neurology
Marco Cassone, Valentina Ferradini, Giuliana Longo, Paola Sarchielli, Donatella Murasecco, Michele Romoli, Elisabetta Pasquini, Giuseppe Novelli, Paolo Prontera, Federica Sangiuolo
No abstract text is available yet for this article.
September 17, 2016: Muscle & Nerve
Savina Tincheva, Bilyana Georgieva, Tihomir Todorov, Alexey Savov, Slavena Tsaneva, Ivan Litvinenko, Vanyo Mitev, Albena Todorova
Myotonia congenita type Becker is an autosomal recessive nondystrophic skeletal muscle disorder, caused by mutations in the CLCN1 gene. The disease is characterized by muscle stiffness and an inability of the muscle to relax after voluntary contraction. Here we report the results from molecular genetic testing of 6 families, referred for sequencing of the CLCN1 gene. The disease causing mutations were detected in 5 of the cases, representing diverse type of nucleotide changes: nonsense (p.Arg894*), splice-site (c...
October 2016: Neuromuscular Disorders: NMD
Mohammad Miryounesi, Soudeh Ghafouri-Fard, Majid Fardaei
Congenital recessive myotonia is a rare genetic disorder caused by mutations in CLCN1, which codes for the main skeletal muscle chloride channel ClC-1. More than 120 mutations have been found in this gene. The main feature of this disorder is muscle membrane hyperexcitability. Here, we report a 59-year male patient suffering from congenital myotonia. He had transient generalized myotonia, which started in early childhood. We analyzed CLCN1 sequence in this patient and other members of his family. We found a new missense mutation in CLCN1 gene (c...
September 2016: Iranian Journal of Medical Sciences
Yi-Jheng Peng, Jing-Jia Huang, Hao-Han Wu, Hsin-Ying Hsieh, Chia-Ying Wu, Shu-Ching Chen, Tsung-Yu Chen, Chih-Yung Tang
Mutations in human CLC-1 chloride channel are associated with the skeletal muscle disorder myotonia congenita. The disease-causing mutant A531V manifests enhanced proteasomal degradation of CLC-1. We recently found that CLC-1 degradation is mediated by cullin 4 ubiquitin ligase complex. It is currently unclear how quality control and protein degradation systems coordinate with each other to process the biosynthesis of CLC-1. Herein we aim to ascertain the molecular nature of the protein quality control system for CLC-1...
2016: Scientific Reports
Samuel T Carrell, Ellie M Carrell, David Auerbach, Sanjay K Pandey, C Frank Bennett, Robert T Dirksen, Charles A Thornton
Myotonic dystrophy type 1 (DM1) is a genetic disorder in which dominant-active DM protein kinase (DMPK) transcripts accumulate in nuclear foci, leading to abnormal regulation of RNA processing. A leading approach to treat DM1 uses DMPK-targeting antisense oligonucleotides (ASOs) to reduce levels of toxic RNA. However, basal levels of DMPK protein are reduced by half in DM1 patients. This raises concern that intolerance for further DMPK loss may limit ASO therapy, especially since mice with Dmpk gene deletion reportedly show cardiac defects and skeletal myopathy...
August 13, 2016: Human Molecular Genetics
Xinglong Yang, Hua Jia, Ran An, Jing Xi, Yanming Xu
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 disease 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. Most of these genetics studies have been conducted outside China, only several PC and MC families accepted gene scan were reported in China...
July 14, 2016: Channels
Paul Dowling, Sandra Murphy, Kay Ohlendieck
INTRODUCTION: Mature skeletal muscles are composed of a complex assembly of slow-twitching, fast-twitching and hybrid fibres. Since muscle fibres exhibit a high degree of cellular plasticity, changed physiological conditions or pathophysiological disturbances have generally a substantial impact on fibre specification. AREAS COVERED: This article reviews the findings from comparative proteomic profiling studies that have focused on neuromuscular diseases and discusses the identified protein changes of fibre type shifting...
August 2016: Expert Review of Proteomics
Praneet Wander, Adedapo Iluyomade, Paul Sanmartin, Akriti Gupta, Mary O'Sullivan
Myotonic dystrophy is a group of inherited disorders called muscular dystrophies. Clinical presentation of this disease is characterised by progressive muscle weakness with myotonia, cataracts, infertility (in males) and cardiac conduction defects. We present a case of a 35 year old male with lung abscess, later diagnosed to be a case of myotonic dystrophy. Lung abscess is an uncommon presentation of this disease and has never been reported before.
2016: Respiratory Medicine Case Reports
Paola Imbrici, Concetta Altamura, Giulia Maria Camerino, Giuseppe Felice Mangiatordi, Elena Conte, Lorenzo Maggi, Raffaella Brugnoni, Kejla Musaraj, Roberta Caloiero, Domenico Alberga, Renè Massimiliano Marsano, Giulia Ricci, Gabriele Siciliano, Orazio Nicolotti, Marina Mora, Pia Bernasconi, Jean-Francois Desaphy, Renato Mantegazza, Diana Conte Camerino
Myotonia congenita is an inherited disease that is characterized by impaired muscle relaxation after contraction caused by loss-of-function mutations in the skeletal muscle ClC-1 channel. We report a novel ClC-1 mutation, T335N, that is associated with a mild phenotype in 1 patient, located in the extracellular I-J loop. The purpose of this study was to provide a solid correlation between T335N dysfunction and clinical symptoms in the affected patient as well as to offer hints for drug development. Our multidisciplinary approach includes patch-clamp electrophysiology on T335N and ClC-1 wild-type channels expressed in tsA201 cells, Western blot and quantitative PCR analyses on muscle biopsies from patient and unaffected individuals, and molecular dynamics simulations using a homology model of the ClC-1 dimer...
June 20, 2016: FASEB Journal: Official Publication of the Federation of American Societies for Experimental Biology
Sabine Rudnik-Schöneborn, Martina Witsch-Baumgartner, Klaus Zerres
BACKGROUND: There are only few reports of pregnancy and delivery in non-dystrophic myotonia or periodic paralysis caused by CLCN1 or SCN4A gene mutations. METHODS: We report the medical histories and personal attitudes of 5 unrelated German patients, 2 following autosomal recessive inheritance (case 1; most likely and case 2; confirmed Becker disease) and 3 following autosomal dominant inheritance (case 3; CLCN1 mutation, cases 4-5; SCN4A mutations), who delivered a total of 9 children...
2016: Gynecologic and Obstetric Investigation
Damien Bachasson, Amélie Moraux, Gwenn Ollivier, Valérie Decostre, Isabelle Ledoux, Teresa Gidaro, Laurent Servais, Anthony Behin, Tanya Stojkovic, Luc J Hébert, Jack Puymirat, Bruno Eymard, Guillaume Bassez, Jean-Yves Hogrel
This study evaluated gait using lower-trunk accelerometry and investigated relationships between gait abnormalities, postural instability, handgrip myotonia, and weakness in lower-limb and axial muscle groups commonly affected in myotonic dystrophy type 1 (DM1). Twenty-two patients (11 men, 11 women; age = 42 years (range: 26-51)) with DM1 and twenty healthy controls (9 men, 11 women; age = 44 years (range: 24-50)) participated in this study. Gait analysis using lower-trunk accelerometry was performed at self-selected walking pace...
July 2016: Neuromuscular Disorders: NMD
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