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Soufan M, Soufan H, Chaudhari K, Klarr J. A Case of Congenital Myasthenia Gravis due to ChAT Gene Mutation in a Term Neonate: A Case Report. AJP Rep 2024; 14:e193-e196. [PMID: 39036811 PMCID: PMC11259492 DOI: 10.1055/a-2363-6319] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Accepted: 07/26/2024] [Indexed: 07/23/2024] Open
Abstract
Congenital myasthenia gravis syndrome (CMS) is a rare genetic heterogeneous disorder due to abnormal neuromuscular transmission caused by several genes. CMS caused by choline acetyltransferase (ChAT) gene mutations have been reported in 53 cases since 2020, and only three of them have been identified as hemizygous mutations. A 1-day-old term neonate was transferred from the nursery to the neonatal intensive care unit on 10 L of oxygen by face mask due to respiratory distress. Family history includes two ChAT gene variants in the elder brother and carrier genes in both parents. She was transitioned to continuous positive airway pressure +5, and chest X-ray showed poor chest expansion. Sepsis workup was negative. She was intubated due to worsening respiratory distress 3 days later. She was started on pyridostigmine, and genetic testing was done, which confirmed two ChAT gene mutations present. The patient had a tracheostomy placed on day 50 and was discharged on day 94 of life on tracheostomy and G-tube, given feeding intolerance. This case illustrates the value of genetic testing in determining the type of CMS to guide management and the importance of obtaining family history to have such syndromes earlier in the differential diagnosis to initiate treatment promptly.
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Affiliation(s)
- Maya Soufan
- Department of Pediatrics, Corewell Health East Royal Oak, Royal Oak, Michigan
| | - Haya Soufan
- AlFaisal University College of Medicine, Riyadh, Saudi Arabia
| | - Kushagra Chaudhari
- Department of Pediatrics, Corewell Health East Royal Oak, Royal Oak, Michigan
| | - Judith Klarr
- Department of Neonatology, Corewell Health East Royal Oak, Royal Oak, Michigan
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Ziaadini B, Ghaderi Yazdi B, Dirandeh E, Boostani R, Karimi N, Panahi A, Kariminejad A, Fadaee M, Ahangari F, Nafissi S. DOK7 congenital myasthenic syndrome: case series and review of literature. BMC Neurol 2024; 24:211. [PMID: 38907197 PMCID: PMC11191154 DOI: 10.1186/s12883-024-03713-0] [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: 12/15/2023] [Accepted: 06/05/2024] [Indexed: 06/23/2024] Open
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) are among the most challenging differential diagnoses in the neuromuscular domain, consisting of diverse genotypes and phenotypes. A mutation in the Docking Protein 7 (Dok-7) is a common cause of CMS. DOK7 CMS requires different treatment than other CMS types. Regarding DOK7's special considerations and challenges ahead of neurologists, we describe seven DOK7 patients and evaluate their response to treatment. METHODS The authors visited these patients in the neuromuscular clinics of Tehran and Kerman Universities of Medical Sciences Hospitals. They diagnosed these patients based on clinical findings and neurophysiological studies, which Whole Exome Sequencing confirmed. For each patient, we tried unique medications and recorded the clinical response. RESULTS The symptoms started from birth to as late as the age of 33, with the mean age of onset being 12.5. Common symptoms were: Limb-girdle weakness in 6, fluctuating symptoms in 5, ptosis in 4, bifacial weakness in 3, reduced extraocular movement in 3, bulbar symptoms in 2 and dyspnea in 2 3-Hz RNS was decremental in 5 out of 6 patients. Salbutamol was the most effective. c.1124_1127dupTGCC is the most common variant; three patients had this variant. CONCLUSION We strongly recommend that neurologists consider CMS in patients with these symptoms and a similar familial history. We recommend prescribing salbutamol as the first-choice treatment option for DOK7 patients.
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Affiliation(s)
- Bentolhoda Ziaadini
- Neurology Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Bardyia Ghaderi Yazdi
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Shariati Hospital, North Karegar St, Tehran, 14117-13135, Iran
- Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Elham Dirandeh
- Clinical Research Development Unit, Kowsar Educational, Research and Therapeutic Hospital, Semnan University of Medical Sciences, Semnan, Iran
| | - Reza Boostani
- Department of Neurology, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Narges Karimi
- Department of Neurology, School of Medicine, Immunogenetics Research Center, Toxoplasmosis Research Center, Clinical Research Development Unit of Bou Ali Sina Hospital, Mazandaran University of Medical Sciences, Sari, Iran
| | - Akram Panahi
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Shariati Hospital, North Karegar St, Tehran, 14117-13135, Iran
- Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | | | - Mahsa Fadaee
- Kariminejad-Najmabadi Pathology & Genetics Center, Tehran, Iran
| | | | - Shahriar Nafissi
- Neuromuscular Research Center, Shariati Hospital, Tehran University of Medical Sciences, Shariati Hospital, North Karegar St, Tehran, 14117-13135, Iran.
- Department of Neurology, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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Poulos J, Samuels M, Palace J, Beeson D, Robb S, Ramdas S, Chan S, Munot P. Congenital myasthenic syndromes: a retrospective natural history study of respiratory outcomes in a single centre. Brain Commun 2023; 5:fcad299. [PMID: 38035366 PMCID: PMC10684295 DOI: 10.1093/braincomms/fcad299] [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: 09/30/2022] [Revised: 06/05/2023] [Accepted: 11/08/2023] [Indexed: 12/02/2023] Open
Abstract
Respiratory problems are a major cause of morbidity and mortality in patients with congenital myasthenic syndromes, a rare heterogeneous group of neuromuscular disorders caused by genetic defects impacting the structure and function of the neuromuscular junction. Recurrent, life-threatening episodic apnoea in early infancy and childhood and progressive respiratory failure requiring ventilation are features of certain genotypes of congenital myasthenic syndromes. Robb et al. published empirical guidance on respiratory management of the congenital myasthenic syndromes, but other than this workshop report, there are little published longitudinal natural history data on respiratory outcomes of these disorders. We report a retrospective, single-centre study on respiratory outcomes in a cohort of 40 well characterized genetically confirmed cases of congenital myasthenic syndromes, including 10 distinct subtypes (DOK7, COLQ, RAPSN, CHAT, CHRNA1, CHRNG, COL13A1, CHRNE, CHRNE fast channel syndrome and CHRNA1 slow channel syndrome), with many followed up over 20 years in our centre. A quantitative and longitudinal analysis of key spirometry and sleep study parameters, as well as a description of historical hospital admissions for respiratory decompensation, provides a snapshot of the respiratory trajectory of congenital myasthenic syndrome patients based on genotype.
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Affiliation(s)
- Jordan Poulos
- Paediatrics, University College London Medical School, London WC1E 6BT, UK
| | - Martin Samuels
- Respiratory Medicine, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Jacqueline Palace
- University of Oxford and Department of Neurology, Oxford Radcliffe Hospitals, Oxford OX3 9DU, UK
| | - David Beeson
- Neurology, Nuffield Department of Clinical Neurosciences, Oxford OX3 7BN, UK
| | - Stephanie Robb
- Dubowitz Neuromuscular Centre, Great Ormond Street Hospital, London WC1N 3JH, UK
| | - Sithara Ramdas
- Neurology, MDUK Neuromuscular Centre, Oxford University Hospitals, Oxford OX3 9DU, UK
| | - Samantha Chan
- Dubowitz Neuromuscular Centre, Great Ormond Street Hospital, London WC1N 3JH, UK
- Neurosciences, University College London and Institute of Child Health, London WC1N 1EH, UK
| | - Pinki Munot
- Dubowitz Neuromuscular Centre, Great Ormond Street Hospital, London WC1N 3JH, UK
- Neurosciences, University College London and Institute of Child Health, London WC1N 1EH, UK
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De Rose DU, Ronci S, Caoci S, Maddaloni C, Diodato D, Catteruccia M, Fattori F, Bosco L, Pro S, Savarese I, Bersani I, Randi F, Trozzi M, Meucci D, Calzolari F, Salvatori G, Solinas A, Dotta A, Campi F. Vocal Cord Paralysis and Feeding Difficulties as Early Diagnostic Clues of Congenital Myasthenic Syndrome with Neonatal Onset: A Case Report and Review of Literature. J Pers Med 2023; 13:jpm13050798. [PMID: 37240968 DOI: 10.3390/jpm13050798] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/21/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
Herein, we present a newborn female with congenital vocal cord paralysis who required a tracheostomy in the neonatal period. She also presented with feeding difficulties. She was later diagnosed with a clinical picture of congenital myasthenia, associated with three variants of the MUSK gene: the 27-month follow-up was described. In particular, the c.565C>T variant is novel and has never been described in the literature; it causes the insertion of a premature stop codon (p.Arg189Ter) likely leading to a consequent formation of a truncated nonfunctioning protein. We also systematically collected and summarized information on patients' characteristics of previous cases of congenital myasthenia with neonatal onset reported in the literature to date, and we compared them to our case. The literature reported 155 neonatal cases before our case, from 1980 to March 2022. Of 156 neonates with CMS, nine (5.8%) had vocal cord paralysis, whereas 111 (71.2%) had feeding difficulties. Ocular features were evident in 99 infants (63.5%), whereas facial-bulbar symptoms were found in 115 infants (73.7%). In one hundred sixteen infants (74.4%), limbs were involved. Respiratory problems were displayed by 97 infants (62.2%). The combination of congenital stridor, particularly in the presence of an apparently idiopathic bilateral vocal cord paralysis, and poor coordination between sucking and swallowing may indicate an underlying congenital myasthenic syndrome (CMS). Therefore, we suggest testing infants with vocal cord paralysis and feeding difficulties for MUSK and related genes to avoid a late diagnosis of CMS and improve outcomes.
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Affiliation(s)
| | - Sara Ronci
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Stefano Caoci
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Chiara Maddaloni
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Daria Diodato
- Neuromuscular and Neurodegenerative Disorders Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Michela Catteruccia
- Neuromuscular and Neurodegenerative Disorders Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Fabiana Fattori
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children Hospital, IRCCS, 00165 Rome, Italy
| | - Luca Bosco
- Neuromuscular and Neurodegenerative Disorders Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
- Department of Science, University Roma Tre, 00146 Rome, Italy
| | - Stefano Pro
- Developmental Neurology Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Immacolata Savarese
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Iliana Bersani
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Franco Randi
- Neurosurgery Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Marilena Trozzi
- Airway Surgery Unit, Pediatric Surgery Department, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Duino Meucci
- Airway Surgery Unit, Pediatric Surgery Department, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Flaminia Calzolari
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Guglielmo Salvatori
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Agostina Solinas
- Neonatal Intensive Care Unit, Sant'Anna Hospital of Ferrara, 44124 Ferrara, Italy
| | - Andrea Dotta
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Francesca Campi
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
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Tsalta-Mladenov M, Levkova M, Georgieva D, Andonova S. Congenital myasthenic syndrome due to a genetic mutation. J Am Assoc Nurse Pract 2023:01741002-990000000-00108. [PMID: 37141567 DOI: 10.1097/jxx.0000000000000878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 04/04/2023] [Indexed: 05/06/2023]
Abstract
ABSTRACT Congenital myasthenic syndrome (CMS) is a group of rare genetic disorders that mimics the symptoms of myasthenia gravis, but it is due to a genetic defect. We present a case of a male CMS patient, and the course of the disease through the years. The patient initially presented with generalized muscle weakness and difficulty swallowing. During the follow-up, he developed difficulty in chewing, bilateral external ophthalmoparesis with an almost full block of eye movements and bulbar syndrome. The case illustrates both the clinical heterogeneity and the progressive worsening of the symptoms of the disease over the years. The optimal treatment for CMS is based on the molecular defect and its localization in the neuromuscular junction. In our case, treatment with pyridostigmine resulted in good long-term control of symptoms. As a result of the patient's good compliance with treatment, he was not admitted to hospital because of respiratory distress. The lack of a unified protocol for the treatment of CMS highlights the need for a more personalized approach when dealing with patients with rare diseases.
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Affiliation(s)
- Mihael Tsalta-Mladenov
- Department of Neurology and Neuroscience, Medical University "Prof. Paraskev Stoyanov," Varna, Bulgaria
- Second Clinic of Neurology with ICU and Stroke Unit, University Multiprofile Hospital for Active Treatment "St. Marina," Varna, Bulgaria
| | - Mariya Levkova
- Department of Medical Genetics, Medical University "Prof. Paraskev Stoyanov," Varna, Bulgaria
- Laboratory of Medical Genetics, University Multiprofile Hospital for Active Treatment "St. Marina," Varna, Bulgaria
| | - Darina Georgieva
- Department of Neurology and Neuroscience, Medical University "Prof. Paraskev Stoyanov," Varna, Bulgaria
- Second Clinic of Neurology with ICU and Stroke Unit, University Multiprofile Hospital for Active Treatment "St. Marina," Varna, Bulgaria
| | - Silva Andonova
- Department of Neurology and Neuroscience, Medical University "Prof. Paraskev Stoyanov," Varna, Bulgaria
- Second Clinic of Neurology with ICU and Stroke Unit, University Multiprofile Hospital for Active Treatment "St. Marina," Varna, Bulgaria
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Lorenzoni PJ, Ducci RDP, Arndt RC, Hrysay NMC, Fustes OJH, Töpf A, Lochmüller H, Werneck LC, Kay CSK, Scola RH. Congenital myasthenic syndrome in a cohort of patients with 'double' seronegative myasthenia gravis. ARQUIVOS DE NEURO-PSIQUIATRIA 2021; 80:69-74. [PMID: 34932651 PMCID: PMC9651496 DOI: 10.1590/0004-282x-anp-2020-0575] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 02/27/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) have some phenotypic overlap with seronegative myasthenia gravis (SNMG). OBJECTIVE The aim of this single center study was to assess the minimum occurrence of CMS misdiagnosed as double SNMG in a Brazilian cohort. METHODS The genetic analysis of the most common mutations in CHRNE, RAPSN, and DOK7 genes was used as the main screening tool. RESULTS We performed genetic analysis in 22 patients with a previous diagnosis of 'double' SNMG. In this study, one CMS patient was confirmed due to the presence of compound heterozygous variants in the CHRNE gene (c.130insG/p.Cys210Phe). CONCLUSIONS This study confirmed that CMS due to CHNRE mutations can be mistaken for SNMG. In addition, our study estimated the prevalence of misdiagnosed CMS to be 4.5% in 'double' SNMG patients of our center. Based on our findings, genetic screening could be helpful in the diagnostic workup of patients with 'double' SNMG in whom differential diagnosis is recommended.
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Affiliation(s)
- Paulo José Lorenzoni
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
| | - Renata Dal-Pra Ducci
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
| | - Raquel Cristina Arndt
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
| | - Nyvia Milicio Coblinski Hrysay
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
| | - Otto Jesus Hernandez Fustes
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
| | - Ana Töpf
- Newcastle University, Institute of Genetic Medicine, John Walton Muscular Dystrophy Research Centre, Newcastle upon Tyne, UK
| | - Hanns Lochmüller
- University of Ottawa, Children's Hospital of Eastern Ontario Research Institute, Department of Medicine, Division of Neurology, Ottawa, Canada.,University of Ottawa, The Ottawa Hospital, Brain and Mind Research Institute, Ottawa, Canada
| | - Lineu Cesar Werneck
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
| | - Cláudia Suemi Kamoi Kay
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
| | - Rosana Herminia Scola
- Universidade Federal do Paraná, Hospital de Clínicas, Departamento de Clínica Médica, Serviço de Doenças Neuromusculares, Curitiba PR, Brazil
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Khaoula R, Cerino M, Da Silva N, Delague V, Nahili H, Kriouile Y, Gorokhova S, Bartoli M, Saïle R, Barakat A, Krahn M. First characterization of congenital myasthenic syndrome type 5 in North Africa. Mol Biol Rep 2021; 48:6999-7006. [PMID: 34553317 DOI: 10.1007/s11033-021-06530-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 06/29/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) are associated with defects in the structure and the function of neuromuscular junctions. These rare disorders can result from mutations in the collagenic tail of endplate acetylcholinesterase (COLQ) essentially associated with autosomal recessive inheritance. With the lowered cost of genetic testing and increased access to next-generation sequencing, many mutations have been reported to date. METHODS AND RESULTS In this study we identified the first COLQ homozygous mutation c.1193T>A in the North African population. This study outlines the genetic and phenotypic features of a CMS patient in a Moroccan family. It also describes a novel COLQ missense mutation associated with CMS-5. CONCLUSION COLQ mutations are probably underdiagnosed in these North African populations, this is an issue as CMS-5 may be treated with ephedrine, and albuterol. Indeed, patients can seriously benefit and even recover after the treatment that should be planned according to genetic tests and clinical findings.
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Affiliation(s)
- Rochdi Khaoula
- Laboratory of Biology and Health, URAC 34, Faculty of Sciences Ben M'Sik, Hassan II University, Casablanca, Morocco. .,Laboratory of Genomics and Human Genetics, Institut Pasteur du Maroc, Casablanca, Morocco.
| | - Mathieu Cerino
- Inserm, U1251-MMG, Marseille Medical Genetics, Aix-Marseille Université, Marseille, France.,Département de Génétique Médicale, APHM, Hôpital Timone Enfants, Marseille, France.,APHM, Hôpital de la Conception, Laboratoire de Biochimie, Marseille, France
| | - Nathalie Da Silva
- Faculté des Sciences Médicales et Paramédicales, Marseille Medical Genetics, Aix Marseille Université, INSERM, Marseille, France
| | - Valerie Delague
- INSERM, MMG, UMR 1251, Aix Marseille University, Marseille, France
| | - Halima Nahili
- Laboratory of Genomics and Human Genetics, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Yamna Kriouile
- Unit of Neuropediatrics and Neurometabolism, Pediatric Department 2, Rabat Children's Hospital, and Faculty of Medicine and Pharmacy of Rabat, University Mohammed V of Rabat, Rabat, Morocco
| | - Svetlana Gorokhova
- Département de Génétique Médicale, APHM, Hôpital Timone Enfants, Marseille, France.,Inserm, U1251-MMG, Marseille Medical Genetics, Aix-Marseille Université, Marseille, France
| | - Marc Bartoli
- Inserm, U1251-MMG, Marseille Medical Genetics, Aix-Marseille Université, Marseille, France
| | - Rachid Saïle
- Laboratory of Biology and Health, URAC 34, Faculty of Sciences Ben M'Sik, Hassan II University, Casablanca, Morocco
| | - Abdelhamid Barakat
- Laboratory of Genomics and Human Genetics, Institut Pasteur du Maroc, Casablanca, Morocco
| | - Martin Krahn
- Département de Génétique Médicale, APHM, Hôpital Timone Enfants, Marseille, France.,Inserm, U1251-MMG, Marseille Medical Genetics, Aix-Marseille Université, Marseille, France
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Akkol EK, Karatoprak GŞ, Carpar E, Hussain Y, Khan H, Aschner M. Effects of Natural Products on Neuromuscular Junction. Curr Neuropharmacol 2021; 20:594-610. [PMID: 34561984 DOI: 10.2174/1570159x19666210924092627] [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: 01/11/2021] [Revised: 05/05/2021] [Accepted: 06/01/2021] [Indexed: 11/22/2022] Open
Abstract
Neuromuscular junction (NMJ) disorders result from damage, malfunction or absence of one or more key proteins involved in neuromuscular transmission, comprising a wide range of disorders. The most common pathology is antibody-mediated or downregulation of ion channels or receptors, resulting in Lambert-Eaton myasthenic syndrome, myasthenia gravis, and acquired neuromyotonia (Isaac's syndrome), and rarely congenital myasthenic syndromes caused by mutations in NMJ proteins. A wide range of symptomatic treatments, immunomodulating therapies, or immunosuppressive drugs have been used to treat NMJ diseases. Future research must be directed at better understanding of the pathogenesis of these diseases, and developing novel disease-specific treatments. Numerous secondary metabolites, especially alkaloids isolated from plants have been used to treat NMJ diseases in traditional and clinical practices. An ethnopharmacological approach has provided leads for identifying new treatment for NMJ diseases. In this review, we performed a literature survey in Pubmed, Science Direct, and Google Scholar to gather information on drug discovery from plant sources for NMJ disease treatments. To date, most research has focused on the effect of herbal remedies on cholinesterase inhibitory and antioxidant activities. This review provides leads for identifying potential new drugs from plant sources for the treatment of NMJ diseases.
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Affiliation(s)
- Esra Küpeli Akkol
- Department of Pharmacognosy, Faculty of Pharmacy, Gazi University, 06330, Ankara. Turkey
| | - Gökçe Şeker Karatoprak
- Department of Pharmacognosy, Faculty of Pharmacy, Erciyes University, 38039, Kayseri. Turkey
| | - Elif Carpar
- Department of Psychiatry, Private French La Paix Hospital, 34360, Istanbul. Turkey
| | - Yaseen Hussain
- College of Pharmaceutical Sciences, Soochow University, Suzhou, Jiangsu, China
| | - Haroon Khan
- Department of Pharmacy, Abdul Wali Khan University Mardan, 23200, Mardan. Pakistan
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine Forchheimer 209 1300 Morris Park Avenue, Bronx, NY 10461, United States
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Novel compound heterozygous variants in the GFPT1 gene leading to rare limb-girdle congenital myasthenic syndrome with rimmed vacuoles. Neurol Sci 2021; 42:3485-3490. [PMID: 33438142 DOI: 10.1007/s10072-020-05021-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2020] [Accepted: 12/21/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND Congenital myasthenic syndrome (CMS) is a heterogeneous group of rare disorders with impaired neuromuscular transmission caused by genetic defects, which is characterized by fatigable muscle weakness. CASE PRESENTATION Herein, we report a case of limb-girdle CMS (LG-CMS) in a 15-year-old Chinese girl with limb weakness and mild ptosis. The patient presented with well-defined clinical manifestations, muscle imaging, and electrophysiological features associated with CMS. On muscle biopsy, in addition to tubular aggregates identified, an extremely unusual pathological change of rimmed vacuoles in muscle fibers was observed. Whole-exome sequencing disclosed two novel heterozygous variants (c.14 T>A and c.581 T>C) in the human glutamine-fructose-6-phosphate transaminase 1 (GFPT1) gene, leading to the substitutions of phenylalanine to tyrosine (p.F5Y) and serine (p.F194S), respectively. Both variants were predicted to be likely pathogenic by SIFT, Polyphen-2, and Mutation Taster. Treatments with pyridostigmine bromide and albuterol produced a dramatic improvement. CONCLUSIONS Collectively, molecular genetic analysis and muscle biopsy play crucial roles in the diagnosis of GFPT1-related LG-CMS with rimmed vacuoles (a rare phenotype of CMS) and have important implications for treatment decision.
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Lu S, Lyu Z, Wang Z, Kou Y, Liu C, Li S, Hu M, Zhu H, Wang W, Zhang C, Kuan YS, Liu YW, Chen J, Tian J. Lipin 1 deficiency causes adult-onset myasthenia with motor neuron dysfunction in humans and neuromuscular junction defects in zebrafish. Theranostics 2021; 11:2788-2805. [PMID: 33456573 PMCID: PMC7806489 DOI: 10.7150/thno.53330] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Accepted: 12/12/2020] [Indexed: 12/03/2022] Open
Abstract
Lipin 1 is an intracellular protein acting as a phosphatidic acid phosphohydrolase enzyme controlling lipid metabolism. Human recessive mutations in LPIN1 cause recurrent, early-onset myoglobinuria, a condition normally associated with muscle pain and weakness. Whether and how lipin 1 deficiency in humans leads to peripheral neuropathy is yet unclear. Herein, two novel compound heterozygous mutations in LPIN1 with neurological disorders, but no myoglobinuria were identified in an adult-onset syndromic myasthenia family. The present study sought to explore the pathogenic mechanism of LPIN1 in muscular and neural development. Methods: The clinical diagnosis of the proband was compared to the known 48 cases of LPIN1 recessive homozygous mutations. Whole-exome sequencing was carried out on the syndromic myasthenia family to identify the causative gene. The pathogenesis of lipin 1 deficiency during somitogenesis and neurogenesis was investigated using the zebrafish model. Whole-mount in situ hybridization, immunohistochemistry, birefringence analysis, touch-evoke escape response and locomotion assays were performed to observe in vivo the changes in muscles and neurons. The conservatism of the molecular pathways regulated by lipin 1 was evaluated in human primary glioblastoma and mouse myoblast cells by siRNA knockdown, drug treatment, qRT-PCR and Western blotting analysis. Results: The patient exhibited adult-onset myasthenia accompanied by muscle fiber atrophy and nerve demyelination without myoglobinuria. Two novel heterozygous mutations, c.2047A>C (p.I683L) and c.2201G>A (p.R734Q) in LPIN1, were identified in the family and predicted to alter the tertiary structure of LPIN1 protein. Lipin 1 deficiency in zebrafish embryos generated by lpin1 morpholino knockdown or human LPIN1 mutant mRNA injections reproduced the myotomes defects, a reduction both in primary motor neurons and secondary motor neurons projections, morphological changes of post-synaptic clusters of acetylcholine receptors, and myelination defects, which led to reduced touch-evoked response and abnormalities of swimming behaviors. Loss of lipin 1 function in zebrafish and mammalian cells also exhibited altered expression levels of muscle and neuron markers, as well as abnormally enhanced Notch signaling, which was partially rescued by the specific Notch pathway inhibitor DAPT. Conclusions: These findings pointed out that the compound heterozygous mutations in human LPIN1 caused adult-onset syndromic myasthenia with peripheral neuropathy. Moreover, zebrafish could be used to model the neuromuscular phenotypes due to the lipin 1 deficiency, where a novel pathological role of over-activated Notch signaling was discovered and further confirmed in mammalian cell lines.
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11
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Stephens BD, Kang MK. Pearls & Oy-sters: The Myasthenic Double Humps. Neurology 2020; 96:545-547. [PMID: 33277409 DOI: 10.1212/wnl.0000000000011287] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Brian D Stephens
- From the Department of Neurology, University of California, San Francisco.
| | - Min K Kang
- From the Department of Neurology, University of California, San Francisco
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12
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Castellanos-Montiel MJ, Velasco I, Escobedo-Avila I. Modeling the neuromuscular junction in vitro: an approach to study neuromuscular junction disorders. Ann N Y Acad Sci 2020; 1488:3-15. [PMID: 33040338 DOI: 10.1111/nyas.14504] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 08/24/2020] [Accepted: 09/09/2020] [Indexed: 12/14/2022]
Abstract
The neuromuscular junction (NMJ) is a specialized structure that works as an interface to translate the action potential of the presynaptic motor neuron (MN) in the contraction of the postsynaptic myofiber. The design of appropriate experimental models is essential to have efficient and reliable approaches to study NMJ development and function, but also to generate conditions that recapitulate distinct features of diseases. Initial studies relied on the use of tissue slices maintained under the same environment and in which single motor axons were difficult to trace. Later, MNs and muscle cells were obtained from primary cultures or differentiation of progenitors and cocultured as monolayers; however, the tissue architecture was lost. Current approaches include self-assembling 3D structures or the incorporation of biomaterials with cells to generate engineered tissues, although the incorporation of Schwann cells remains a challenge. Thus, numerous investigations have established different NMJ models, some of which are quite complex and challenging. Our review summarizes the in vitro models that have emerged in recent years to coculture MNs and skeletal muscle, trying to mimic the healthy and diseased NMJ. We expect our review may serve as a reference for choosing the appropriate experimental model for the required purposes of investigation.
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Affiliation(s)
- María José Castellanos-Montiel
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.,Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montréal, Quebec, Canada
| | - Iván Velasco
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico.,Laboratorio de Reprogramación Celular, Instituto Nacional de Neurología y Neurocirugía "Manuel Velasco Suárez", Mexico City, Mexico
| | - Itzel Escobedo-Avila
- Instituto de Fisiología Celular-Neurociencias, Universidad Nacional Autónoma de México (UNAM), Mexico City, Mexico
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Congenital myasthenic syndromes in the Thai population: Clinical findings and novel mutations. Neuromuscul Disord 2020; 30:851-858. [PMID: 32978031 DOI: 10.1016/j.nmd.2020.08.362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2019] [Revised: 08/26/2020] [Accepted: 08/27/2020] [Indexed: 11/23/2022]
Abstract
Congenital myasthenic syndromes (CMS) comprise a heterogeneous group of genetic disorders of the neuromuscular junction. Next generation sequencing has been increasingly used for molecular diagnosis in CMS patients. This study aimed to identify the disease-causing variants in Thai patients. We recruited patients with a diagnosis of CMS based on clinical and electrophysiologic findings, and whole exome sequencing was performed. Thirteen patients aged from 2 to 54 years (median: 8 years) from 12 families were enrolled. Variants were identified in 9 of 13 patients (69%). Five novel variants and two previously reported variant were found in the COLQ, RAPSN and CHRND gene. The previously reported c.393+1G>A splice site variant in the COLQ gene was found in a majority of patients. Five patients harbor the homozygous splice site c.393+1G>A variant, and two patients carry compound heterozygous c.393+1G>A, c.718-1G>T, and c.393+1G>A, c.865G>T (p.Gly289Ter) variants. The novel variants were also found in RAPSN (p.Cys251del, p.Arg282Cys) and CHRND (p.Met481del). Molecular diagnosis in CMS patients can guide treatment decisions and may be life changing, especially in patients with COLQ mutations.
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14
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Troha Gergeli A, Neubauer D, Golli T, Butenko T, Loboda T, Maver A, Osredkar D. Prevalence and genetic subtypes of congenital myasthenic syndromes in the pediatric population of Slovenia. Eur J Paediatr Neurol 2020; 26:34-38. [PMID: 32070632 DOI: 10.1016/j.ejpn.2020.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/08/2020] [Accepted: 02/07/2020] [Indexed: 12/15/2022]
Abstract
AIM Congenital myasthenic syndromes (CMS) are rare, genetically and phenotypically diverse disorders of neuromuscular transmission. Data on prevalence among children are scarce. Whole exome sequencing facilitated discovery of novel CMS mutations and enabled targeted treatment. Our aim was to identify the prevalence, genetic subtypes and clinical characteristics of CMS in pediatric population of Slovenia. METHODS In this observational, national, cross-sectional study, medical records were retrospectively reviewed. Children with genetically confirmed CMS, referred over a 19 - year period (2000-2018) to the University Medical Centre, Ljubljana, Slovenia, were included in the study. Genetic and phenotypic characteristics were collected and prevalence of CMS in children was calculated. RESULTS Eight children with a confirmed genetic mutation in 5 different genes (CHRNE, CHRND, RAPSN, CHAT, MUSK) causative of the CMS were identified. Calculated prevalence of genetically confirmed CMS was 22.2 cases per 1.000.000 children at the end of 2018. INTERPRETATION The prevalence of genetically confirmed CMS in Slovenian children at the end of 2018 exceeds previously reported prevalence by more than two-fold, which suggests that prevalence in the literature is likely to be underestimated. Two extremely rarely detected mutations in MUSK and CHRND gene were detected and patient's clinical descriptions add important information on genotype-phenotype correlation.
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Affiliation(s)
- Anja Troha Gergeli
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia
| | - David Neubauer
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia
| | - Tanja Golli
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia
| | - Tita Butenko
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia
| | - Tanja Loboda
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia
| | - Aleš Maver
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Slovenia
| | - Damjan Osredkar
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia.
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15
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Shen Y, Wang B, Zheng X, Zhang W, Wu H, Hei M. A Neonate With MuSK Congenital Myasthenic Syndrome Presenting With Refractory Respiratory Failure. Front Pediatr 2020; 8:166. [PMID: 32373561 PMCID: PMC7176811 DOI: 10.3389/fped.2020.00166] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Accepted: 03/24/2020] [Indexed: 12/04/2022] Open
Abstract
This was a Chinese neonatal congenital myasthenic syndromes case caused by muscle skeletal receptor tyrosine kinase gene mutations, which have not been recorded in the Human Gene Mutation Database. The newborn girl had refractory respiratory failure from birth to death, and failed extubation seven times. She had two heterozygous mutations: a non-sense mutation c.2062C>T (p.Q688X) inherited from father and a missense mutation c.2324T>C (p.F775S) inherited from mother, which was predicted pathogenic and harmful by bioinformatic softwares SIFT, PolyPhen_2 and REVEL. She positively responded to Neostigmine, but her parent quitted treatment when Pyridostigmine Bromide (2 mg/kg Q12 h) had been given for 8 days. She died 2 days after she was taken home by her parents on age of 56 days.
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Affiliation(s)
- Yanhua Shen
- Neonatal Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
- National Center for Children's Health, Beijing, China
| | - Bo Wang
- Neonatal Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
- National Center for Children's Health, Beijing, China
| | - Xia Zheng
- Neonatal Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
- National Center for Children's Health, Beijing, China
| | - Wenwen Zhang
- Neonatal Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
- National Center for Children's Health, Beijing, China
| | - Hailan Wu
- Neonatal Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
- National Center for Children's Health, Beijing, China
| | - Mingyan Hei
- Neonatal Center, Beijing Children's Hospital, Capital Medical University, Beijing, China
- National Center for Children's Health, Beijing, China
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16
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Lorenzoni PJ, Kay CSK, Arndt RC, Hrysay NMC, Ducci RDP, Fustes OHJ, Töpf A, Lochmüller H, Werneck LC, Scola RH. Congenital myasthenic syndrome due to DOK7 mutation in a cohort of patients with 'unexplained' limb-girdle muscular weakness. J Clin Neurosci 2020; 75:195-198. [PMID: 32238315 DOI: 10.1016/j.jocn.2020.01.080] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 01/27/2020] [Indexed: 10/24/2022]
Abstract
Congenital myasthenic syndromes (CMS) associated with pathogenic variants in the DOK7 gene (DOK7-CMS) have phenotypic overlap with other neuromuscular disorders associated with limb-girdle muscular weakness (LGMW). Genetic analysis of the most common mutation (c.1124_1127dupTGCC) in DOK7 was performed in 34 patients with "unexplained" LGMW associated with non-specific changes in muscle biopsy. Of the 34 patients, one patient showed the DOK7 c.1124_1127dupTGCC variant in homozygousity. Our study estimates the minimum prevalence of undiagnosed DOK7-CMS to be 2.9% in southern Brazilian patients from our centre. Our data confirm that clinicians should look for DOK7-CMS patients when the clinical manifestation is an 'unexplained' LGMW, mainly if associated with non-specific changes in muscle biopsy.
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Affiliation(s)
- Paulo José Lorenzoni
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Cláudia Suemi Kamoi Kay
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Raquel Cristina Arndt
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Nyvia Milicio Coblinski Hrysay
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Renata Dal-Pra Ducci
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Otto H Jesus Fustes
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Division of Neurology, Department of Medicine, The Ottawa Hospital; and Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada
| | - Lineu Cesar Werneck
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil
| | - Rosana Herminia Scola
- Service of Neuromuscular Disorders, Division of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná (UFPR), Curitiba, Brazil.
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Leite Schetino LP, Fonseca M, Magalhães Gomes MPS, Costa Valadão PA, Camargo WL, Rodrigues HA, Andrade JN, Arantes‐Costa FM, Naves LA, Prado CM, Prado VF, Prado MAM, Guatimosim C. Evaluation of the neuromuscular junction in a middle‐aged mouse model of congenital myasthenic syndrome. Muscle Nerve 2019; 60:790-800. [DOI: 10.1002/mus.26710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/06/2019] [Accepted: 09/11/2019] [Indexed: 12/19/2022]
Affiliation(s)
| | - Matheus Fonseca
- Laboratório Nacional de BiociênciasCentro Nacional de Pesquisa em Energia e Materiais Campinas São Paulo Brazil
| | | | | | - Wallace Lucio Camargo
- Departamento de Fisiologia e BiofísicaUniversidade Federal de Minas Gerais Belo Horizonte Minas Gerais Brazil
| | - Hermann Alecsandro Rodrigues
- Departamento de Ciências Básicas da Vida, Instituto de Ciências da VidaUniversidade Federal de Juiz de Fora Campus Governador Valadares Minas Gerais Brazil
| | - Jéssica Neves Andrade
- Departamento de MorfologiaUniversidade Federal de Minas Gerais Belo Horizonte Minas Gerais Brazil
| | | | - Lígia Araujo Naves
- Departamento de Fisiologia e BiofísicaUniversidade Federal de Minas Gerais Belo Horizonte Minas Gerais Brazil
| | - Carla Máximo Prado
- Departmento de BiociênciasUniversidade Federal de São Paulo, Campus Baixada Santista São Paulo Brazil
| | - Vânia Ferreira Prado
- Robarts Research Institute and Department of Physiology and Pharmacology and Anatomy & Cell BiologyUniversity of Western Ontario London Ontario Canada
| | - Marco Antônio Máximo Prado
- Robarts Research Institute and Department of Physiology and Pharmacology and Anatomy & Cell BiologyUniversity of Western Ontario London Ontario Canada
| | - Cristina Guatimosim
- Departamento de MorfologiaUniversidade Federal de Minas Gerais Belo Horizonte Minas Gerais Brazil
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Donkervoort S, Dowling JJ, Laporte J, MacArthur D, Bönnemann CG. 214th ENMC International Workshop: Establishing an international consortium for gene discovery and clinical research for Congenital Muscle Disease, Heemskerk, the Netherlands, 6-18 October 2015. Neuromuscul Disord 2019; 29:644-650. [PMID: 31400830 DOI: 10.1016/j.nmd.2019.07.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 07/11/2019] [Indexed: 10/26/2022]
Affiliation(s)
- Sandra Donkervoort
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - James J Dowling
- Division of Neurology, Hospital for Sick Children, Toronto, Ontario, Canada.
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, IGBMC, Illkirch, France
| | | | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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Camilleri M, Wieben E, Eckert D, Carlson P, O’Dwyer RH, Gibbons D, Acosta A, Klee EW. Familial chronic megacolon presenting in childhood or adulthood: Seeking the presumed gene association. Neurogastroenterol Motil 2019; 31:e13550. [PMID: 30663199 PMCID: PMC6432647 DOI: 10.1111/nmo.13550] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 12/14/2018] [Accepted: 12/18/2018] [Indexed: 12/18/2022]
Abstract
OBJECTIVE We identified a pedigree over five generations with 49 members, some of whom had chronic megacolon presenting in adolescence or adulthood. We aimed to assess the genetic cause of chronic megacolon through clinical and DNA studies. DESIGN After ethical approval and informed consent, family members provided answers to standard bowel disease questionnaires, radiological or surgical records, and DNA (buccal mucosal scraping). Exome DNA sequencing of colon tissue or blood DNA from seven family members with colon or duodenal dilatation, or no megacolon (n = 1) was carried out. Sanger sequencing was performed in 22 additional family members to further evaluate candidate variants. The study focused on genes of potential relevance to enteric nerve (ENS) maturation and Hirschsprung's disease or megacolon, based on the literature (GFRA1, NKX2-1, KIF26A, TPM3, ACTG2, SCN10A, and C17orf107 [CHRNE]) and other genetic variants that co-segregated with megacolon in the six affected family members. RESULTS Information was available in all except five members alive at time of study; among 30 members who provided DNA, six had definite megacolon, one megaduodenum, seven significant constipation without bowel dilatation, and 16 normal bowel function by questionnaire. Among genes studied, SEMA3F (g.3:50225360A>G; c1873A>G) was found in 6/6 family members with megacolon. The SEMA3F gene variant was assessed as potentially pathogenic, based on M-CAP in silico prediction. SEMA3F function is associated with genes (KIT and PDGFRB) that impact intestinal pacemaker function. CONCLUSION Familial chronic megacolon appears to be associated with SEMA3F, which is associated with genes impacting enteric nerve or pacemaker function.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota
| | - Eric Wieben
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
| | - Deborah Eckert
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota
| | - Paula Carlson
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota
| | - Ralph Hurley O’Dwyer
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota
| | - Denys Gibbons
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota
| | - Andres Acosta
- Clinical Enteric Neuroscience Translational and Epidemiological Research (C.E.N.T.E.R.), Mayo Clinic, Rochester, Minnesota
| | - Eric W. Klee
- Center for Individualized Medicine, Mayo Clinic, Rochester, Minnesota
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20
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Heikkinen A, Härönen H, Norman O, Pihlajaniemi T. Collagen XIII and Other ECM Components in the Assembly and Disease of the Neuromuscular Junction. Anat Rec (Hoboken) 2019; 303:1653-1663. [PMID: 30768864 DOI: 10.1002/ar.24092] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Revised: 08/17/2018] [Accepted: 09/27/2018] [Indexed: 12/15/2022]
Abstract
Alongside playing structural roles, the extracellular matrix (ECM) acts as an interaction platform for cellular homeostasis, organ development, and maintenance. The necessity of the ECM is highlighted by the diverse, sometimes very serious diseases that stem from defects in its components. The neuromuscular junction (NMJ) is a large peripheral motor synapse differing from its central counterparts through the ECM included at the synaptic cleft. Such synaptic basal lamina (BL) is specialized to support NMJ establishment, differentiation, maturation, stabilization, and function and diverges in molecular composition from the extrasynaptic ECM. Mutations, toxins, and autoantibodies may compromise NMJ integrity and function, thereby leading to congenital myasthenic syndromes (CMSs), poisoning, and autoimmune diseases, respectively, and all these conditions may involve synaptic ECM molecules. With neurotransmission degraded or blocked, muscle function is impaired or even prevented. At worst, this can be fatal. The article reviews the synaptic BL composition required for assembly and function of the NMJ molecular machinery through the lens of studies primarily with mouse models but also with human patients. In-depth focus is given to collagen XIII, a postsynaptic-membrane-spanning but also shed ECM protein that in recent years has been revealed to be a significant component for the NMJ. Its deficiency in humans causes CMS, and autoantibodies against it have been recognized in autoimmune myasthenia gravis. Mouse models have exposed numerous details that appear to recapitulate human NMJ phenotypes relatively faithfully and thereby can be readily used to generate information necessary for understanding and ultimately treating human diseases. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Anne Heikkinen
- Oulu Center for Cell-Matrix Research, Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Heli Härönen
- Oulu Center for Cell-Matrix Research, Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Oula Norman
- Oulu Center for Cell-Matrix Research, Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
| | - Taina Pihlajaniemi
- Oulu Center for Cell-Matrix Research, Biocenter Oulu, Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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Abstract
OBJECTIVES To investigate the mutational spectrum and genotype-phenotype correlation in Indian patients with congenital myasthenic syndrome (CMS), using next-generation sequencing of 5 genes. METHODS CHRNE, COLQ, DOK7, RAPSN, and GFPT1 were sequenced in 25 affected patients. RESULTS We found clinically significant variants in 18 patients, of which variants in CHRNE were the most common, and 9 were novel. A common pathogenic COLQ variant was also detected in 4 patients with isolated limb-girdle congenital myasthenia. CONCLUSIONS Targeted screening of 5 genes is an effective alternate test for CMS, and an affordable one even in a developing country such as India. In addition, we recommend that patients with isolated limb-girdle congenital myasthenia be screened initially for the common COLQ pathogenic variant. This study throws the first light on the genetic landscape of CMSs in India.
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Johnson A, Subramony SH, Chuquilin M. Delayed diagnosis of DOK7 congenital myasthenic syndrome: Case report and literature review. Neurol Clin Pract 2018; 8:e40-e42. [PMID: 30588388 DOI: 10.1212/cpj.0000000000000530] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 07/26/2018] [Indexed: 11/15/2022]
Affiliation(s)
- Amber Johnson
- Department of Neurology, University of Florida, Gainesville
| | - S H Subramony
- Department of Neurology, University of Florida, Gainesville
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Egashira Y, Zempo B, Sakata S, Ono F. Recent advances in neuromuscular junction research prompted by the zebrafish model. CURRENT OPINION IN PHYSIOLOGY 2018. [DOI: 10.1016/j.cophys.2018.06.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Lorenzoni PJ, Scola RH, Kay CSK, Werneck LC, Horvath R, Lochmüller H. How to Spot Congenital Myasthenic Syndromes Resembling the Lambert–Eaton Myasthenic Syndrome? A Brief Review of Clinical, Electrophysiological, and Genetics Features. Neuromolecular Med 2018; 20:205-214. [DOI: 10.1007/s12017-018-8490-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 04/16/2018] [Indexed: 01/26/2023]
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Yang K, Cheng H, Yuan F, Meng L, Yin R, Zhang Y, Wang S, Wang C, Lu Y, Xi J, Lu Q, Chen Y. CHRNE compound heterozygous mutations in congenital myasthenic syndrome: A case report. Medicine (Baltimore) 2018; 97:e0347. [PMID: 29702980 PMCID: PMC5944527 DOI: 10.1097/md.0000000000010347] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
RATIONALE Congenital myasthenic syndrome (CMSs) are a group of rare genetic disorders of the neurological junction, which can result in structural or functional weakness. Here, we characterized a case of CMS in order to clarify the diagnosis and expand the understanding of it. The molecular diagnosis had implications for choice of treatment and genetic counseling. PATIENT CONCERNS A 3-year-old male patient with CMS had ptosis and limb weakness for 2 months after birth. Clinical course and electrophysiological, imaging, and genetic findings were assessed. Protein structure/function was predicted. A novel mutation of c.295C>T (exon 4) and another known mutation of c.442T>A (exon 5) were found in CHRNE. Both mutations localized in conserved sequences. The c.442T>A (p.C148S) missense mutation in CHRNE was predicted to be damaging/deleterious. The iterative threading assembly refinement (I-TASSER) server generated vastly different 3-dimensional (3D) atomic models based on protein sequences from wide-type and novel nonsense mutation of c.295C>T (p.R99X) in CHRNE. DIAGNOSES The diagnosis of CMS with CHRNE mutations in Han Chinese was confirmed. INTERVENTIONS The patient was given prednisone (10 mg, once daily, taken orally) and pyridostigmine (15 mg, three times a day, taken orally). OUTCOMES The patient had a moderate response to prednisone and pyridostigmine. LESSONS We expanded the genotype and phenotype of CMS with CHRNE mutations in Han Chinese and provided new insights into the molecular mechanism of CMS and help to the diagnosis and treatment of CMS.
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Affiliation(s)
| | | | | | - Linyi Meng
- Department of Pharmacy, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai, China
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Congenital Myasthenic Syndromes. Neuromuscul Disord 2018. [DOI: 10.1007/978-981-10-5361-0_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Liu W, Chakkalakal JV. The Composition, Development, and Regeneration of Neuromuscular Junctions. Curr Top Dev Biol 2018; 126:99-124. [DOI: 10.1016/bs.ctdb.2017.08.005] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Feng H, Zhou H. New compound heterozygous variants of the cholinergic receptor nicotinic delta subunit gene in a Chinese male with congenital myasthenic syndrome: A case report. Medicine (Baltimore) 2017; 96:e8981. [PMID: 29390429 PMCID: PMC5758131 DOI: 10.1097/md.0000000000008981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
INTRODUCTION Congenital myasthenic syndromes (CMS) are a group of genetic disorders that stem mostly from molecular defects in nicotinic acetylcholine receptors (AChRs). Defects in the cholinergic receptor nicotinic delta subunit (CHRND) gene can cause a series of myasthenic syndromes. Here, we report 2 new compound heterozygous variants of the CHRND gene in a Chinese male with CMS. CASE PRESENTATION A 43-year-old Chinese male presented with progressive muscle weakness, difficulty chewing, and an inability to lift his head from the time he was 8 years old. He was treated with pyridostigmine, which was partially effective. Two weeks prior, he was hospitalized for dyspnea. Upon examination, he was unable to drum his cheeks and exhibited fatigable muscle weakness and facial muscle atrophy. Sequencing of his exome revealed 2 previously unreported mutations in CHRND, c.59G>A (exon2) and c.423G>C (exon5). CONCLUSIONS We identified a new mutational site that contributes to the onset of CMS.
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Schwartz M, Sternberg D, Whalen S, Afenjar A, Isapof A, Chabrol B, Portnoï MF, Heide S, Keren B, Chantot-Bastaraud S, Siffroi JP. How chromosomal deletions can unmask recessive mutations? Deletions in 10q11.2 associated with CHAT or SLC18A3 mutations lead to congenital myasthenic syndrome. Am J Med Genet A 2017; 176:151-155. [PMID: 29130637 DOI: 10.1002/ajmg.a.38515] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Revised: 09/24/2017] [Accepted: 09/26/2017] [Indexed: 11/06/2022]
Abstract
A congenital myasthenia was suspected in two unrelated children with very similar phenotypes including several episodes of severe dyspnea. Both children had a 10q11.2 deletion revealed by Single Nucleotide Polymorphisms array or by Next Generation Sequencing analysis. The deletion was inherited from the healthy mother in the first case. These deletions unmasked a recessive mutation at the same locus in both cases, but in two different genes: CHAT and SLC18A3.
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Affiliation(s)
- Mathias Schwartz
- AP-HP, Département de Génétique Médicale, Hôpital Armand Trousseau, UPMC, Paris, France
| | - Damien Sternberg
- AP-HP, Hôpital Pitié-Salpêtrière, Biochimie et Génétique, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, Paris, France
| | - Sandra Whalen
- AP-HP, Hôpital Armand Trousseau, UF de Génétique Clinique, UPMC, Paris, France
| | - Alexandra Afenjar
- AP-HP, Hôpital Armand Trousseau, UF de Génétique Clinique, UPMC, Paris, France
| | - Arnaud Isapof
- AP-HP, Hôpital Armand Trousseau, Unité de Neuropédiatrie et Pathologie du Développement, UPMC, Paris, France
| | - Brigitte Chabrol
- CHU de Marseille, Hôpital de la Timone, Service de Neurologie Pédiatrique, Inserm U1127, CNRS UMR 7225, UPMC, Centre de Recherche de l'Institut du Cerveau et de la Moëlle épinière, Paris, France
| | - Marie-France Portnoï
- AP-HP, Département de Génétique Médicale, Hôpital Armand Trousseau, UPMC, Paris, France
| | - Solveig Heide
- AP-HP, Département de Génétique Médicale, Hôpital Armand Trousseau, UPMC, Paris, France
| | - Boris Keren
- AP-HP, Département de Génétique, Hôpital de la Pitié Salpêtrière, Paris, France
| | | | - Jean-Pierre Siffroi
- AP-HP, Département de Génétique Médicale, Hôpital Armand Trousseau, UPMC, Paris, France
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Bhoopalan SV, Jain R. Case 2: Hypotonia and Muscle Weakness since Birth in a 2-year-old Boy. Pediatr Rev 2017; 38:531. [PMID: 29093122 DOI: 10.1542/pir.2016-0187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
| | - Renu Jain
- Department of Pediatrics, University of Nevada Las Vegas, Las Vegas, NV
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Fatigue in Rapsyn-Deficient Zebrafish Reflects Defective Transmitter Release. J Neurosci 2017; 36:10870-10882. [PMID: 27798141 DOI: 10.1523/jneurosci.0505-16.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 09/03/2016] [Indexed: 12/29/2022] Open
Abstract
Rapsyn-deficient myasthenic syndrome is characterized by a weakness in voluntary muscle contraction, a direct consequence of greatly reduced synaptic responses that result from poorly clustered acetylcholine receptors. As with other myasthenic syndromes, the general muscle weakness is also accompanied by use-dependent fatigue. Here, we used paired motor neuron target muscle patch-clamp recordings from a rapsyn-deficient mutant line of zebrafish to explore for the first time the mechanisms causal to fatigue. We find that synaptic responses in mutant fish can follow faithfully low-frequency stimuli despite the reduced amplitude. This is in part helped by a compensatory increase in the number of presynaptic release sites in the mutant fish. In response to high-frequency stimulation, both wild-type and mutant neuromuscular junctions depress to steady-state response levels, but the latter shows exaggerated depression. Analysis of the steady-state transmission revealed that vesicle reloading and release at individual release sites is significantly slower in mutant fish during high-frequency activities. Therefore, reductions in postsynaptic receptor density and compromised presynaptic release collectively serve to reduce synaptic strength to levels that fall below the threshold for muscle action potential generation, thus accounting for use-dependent fatigue. Our findings raise the possibility that defects in motor neuron function may also be at play in other myasthenic syndromes that have been mapped to mutations in muscle-specific proteins. SIGNIFICANCE STATEMENT Use-dependent fatigue accompanies many neuromuscular myasthenic syndromes, including muscle rapsyn deficiency. Here, using a rapsyn-deficient line of zebrafish, we performed paired motor neuron target muscle patch-clamp recordings to investigate the mechanisms causal to this phenomenon. Our findings indicate that the reduced postsynaptic receptor density resulting from defective rapsyn contributes to weakness, but is not solely responsible for use-dependent fatigue. Instead, we find unexpected involvement of altered transmitter release from the motor neuron. Specifically, slowed reloading of vesicle release sites leads to augmented synaptic depression during repeated action potentials. Even at moderate stimulus frequencies, the depression levels for evoked synaptic responses fall below the threshold for the generation of muscle action potentials. The associated contraction failures are manifest as use-dependent fatigue.
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Yiş U, Becker K, Kurul SH, Uyanik G, Bayram E, Haliloğlu G, Polat Aİ, Ayanoğlu M, Okur D, Tosun AF, Serdaroğlu G, Yilmaz S, Topaloğlu H, Anlar B, Cirak S, Engel AG. Genetic Landscape of Congenital Myasthenic Syndromes From Turkey: Novel Mutations and Clinical Insights. J Child Neurol 2017; 32:759-765. [PMID: 28464723 PMCID: PMC5655993 DOI: 10.1177/0883073817705252] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Congenital myasthenic syndromes are clinically and genetically heterogeneous disorders of neuromuscular transmission. Most are treatable, but certain subtypes worsen with cholinesterase inhibitors. This underlines the importance of genetic diagnosis. Here, the authors report on cases with genetically proven congenital myasthenic syndromes from Turkey. The authors retrospectively reviewed their experience of all patients with congenital myasthenic syndromes, referred over a 5-year period (2011-2016) to the Child Neurology Department of Dokuz Eylül University, Izmir, Turkey. In addition, PubMed was searched for published cases of genetically proven congenital myasthenic syndromes originating from Turkey. In total, the authors identified 43 (8 new patients, 35 recently published patients) cases. Defects in the acetylcholine receptor (n = 15; 35%) were the most common type, followed by synaptic basal-lamina associated (n = 14; 33%) and presynaptic syndromes (n = 10; 23%). The authors had only 3 cases (7%) who had defects in endplate development. One patient had mutation GFPT1 gene (n = 1; 2%). Knowledge on congenital myasthenic syndromes and related genes in Turkey will lead to prompt diagnosis and treatment of these rare neuromuscular disorders.
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Affiliation(s)
- Uluç Yiş
- Dokuz Eylül University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Kerstin Becker
- Cologne University, Department of Pediatrics, Center for Molecular Medicine Cologne, Cologne, GERMANY
| | - Semra Hız Kurul
- Dokuz Eylül University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Gökhan Uyanik
- Center for Medical Genetics, Hanusch Hospital, Vienna, AUSTRIA
- Medical Faculty, Sigmund Freud University, Vienna, AUSTRIA
| | - Erhan Bayram
- Dokuz Eylül University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Göknur Haliloğlu
- Hacettepe University, School of Medicine, Department of Pediatrics, Division of Child Neurology, Ankara, TURKEY
| | - Ayşe İpek Polat
- Dokuz Eylül University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Müge Ayanoğlu
- Dokuz Eylül University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Derya Okur
- Dokuz Eylül University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Ayşe Fahriye Tosun
- Adnan Menderes University, School of Medicine, Department of Pediatrics, Division of Child Neurology, Aydın, TURKEY
| | - Gül Serdaroğlu
- Ege University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Sanem Yilmaz
- Ege University, School of Medicine, Department of Pediatrics, Division of Child Neurology, İzmir, TURKEY
| | - Haluk Topaloğlu
- Hacettepe University, School of Medicine, Department of Pediatrics, Division of Child Neurology, Ankara, TURKEY
| | - Banu Anlar
- Hacettepe University, School of Medicine, Department of Pediatrics, Division of Child Neurology, Ankara, TURKEY
| | - Sebahattin Cirak
- Cologne University, Department of Pediatrics, Center for Molecular Medicine Cologne, Cologne, GERMANY
| | - Andrew G. Engel
- Mayo Clinic, Rochester, Department of Neurology, MN 55905, USA
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Ghosh PS. Clinical Reasoning: A child with delayed motor milestones and ptosis. Neurology 2017; 88:e158-e163. [DOI: 10.1212/wnl.0000000000003844] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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Aharoni S, Sadeh M, Shapira Y, Edvardson S, Daana M, Dor-Wollman T, Mimouni-Bloch A, Halevy A, Cohen R, Sagie L, Argov Z, Rabie M, Spiegel R, Chervinsky I, Orenstein N, Engel AG, Nevo Y. Congenital myasthenic syndrome in Israel: Genetic and clinical characterization. Neuromuscul Disord 2016; 27:136-140. [PMID: 28024842 DOI: 10.1016/j.nmd.2016.11.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 11/20/2016] [Accepted: 11/21/2016] [Indexed: 10/20/2022]
Abstract
The objective of the study was to evaluate the epidemiology of patients with congenital myasthenic syndrome (CMS) in Israel. Targeted mutation analysis was performed based on the clinical symptoms and electrophysiological findings for known CMS. Additional specific tests were performed in patients of Iranian and/or Iraqi Jewish origin. All medical records were reviewed and clinical data, genetic mutations and outcomes were recorded. Forty-five patients with genetic mutations in known CMS genes from 35 families were identified. Mutations in RAPSN were identified in 13 kinships in Israel. The most common mutation was c.-38A>G detected in 8 patients of Iranian and/or Iraqi Jewish origin. Four different recessive mutations in COLQ were identified in 11 kinships, 10 of which were of Muslim-Arab descent. Mutations in CHRNE were identified in 7 kinships. Less commonly detected mutations were in CHRND, CHAT, GFPT1 and DOK7. In conclusion, mutations in RAPSN and COLQ are the most common causes of CMS in our cohort. Specific mutations in COLQ, RAPSN, and CHRNE occur in specific ethnic populations and should be taken into account when the diagnosis of a CMS is suspected.
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Affiliation(s)
- Sharon Aharoni
- Institute of Child Neurology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Menachem Sadeh
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Neurology, Wolfson Medical Center, Holon, Israel
| | - Yehuda Shapira
- Neuropediatric Unit, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Simon Edvardson
- Neuropediatric Unit, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Muhannad Daana
- Neuropediatric Unit, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Talia Dor-Wollman
- Neuropediatric Unit, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Aviva Mimouni-Bloch
- Pediatric Neurology and Developmental Unit, Loewenstein Rehabilitation Hospital, Raanana, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ayelet Halevy
- Institute of Child Neurology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Rony Cohen
- Institute of Child Neurology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Liora Sagie
- Pediatric Neurology Unit, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Zohar Argov
- Department of Neurology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Malcolm Rabie
- Institute of Child Neurology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ronen Spiegel
- Genetic Institute, Emek Medical Center, Afula, Israel
| | | | - Naama Orenstein
- Genetics Unit, Schneider Children's Medical Center of Israel, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Andrew G Engel
- Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN, USA
| | - Yoram Nevo
- Institute of Child Neurology, Schneider Children's Medical Center of Israel, Petach Tikva, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Natera-de Benito D, Domínguez-Carral J, Muelas N, Nascimento A, Ortez C, Jaijo T, Arteaga R, Colomer J, Vilchez JJ. Phenotypic heterogeneity in two large Roma families with a congenital myasthenic syndrome due to CHRNE 1267delG mutation. A long-term follow-up. Neuromuscul Disord 2016; 26:789-795. [PMID: 27634344 DOI: 10.1016/j.nmd.2016.08.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 07/22/2016] [Accepted: 08/10/2016] [Indexed: 11/29/2022]
Abstract
Congenital myasthenic syndromes (CMS) are a heterogeneous group of genetic disorders. Mutations in CHRNE are one of the most common cause of them and the ɛ1267delG frameshifting mutation is described to be present on at least one allele of 60% of patients with CHRNE mutations. We present a comprehensive description of the heterogeneous clinical features of the CMS caused by the homozygous 1267delG mutation in the AChR Ɛ subunit in nine members of two large Gipsy kindreds. Our observations indicate that founder Roma mutation 1267delG leads to a phenotype further characterized by ophthalmoplegia, bilateral ptosis, and good response to pyridostigmine and 3,4-DAP; but also by facial weakness, bulbar symptoms, neck muscle weakness, and proximal limb weakness that sometimes entails the loss of ambulation. Interestingly, we found in our series a remarkable proportion of patients with a progressive or fluctuating course of the disease. This finding is in some contrast with previous idea that considered this form of CMS as benign, non progressive, and with a low impact on the capacity of ambulation.
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Affiliation(s)
- D Natera-de Benito
- Department of Pediatrics, Hospital Universitario de Fuenlabrada, Madrid, Spain.
| | - J Domínguez-Carral
- Department of Pediatrics, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | - N Muelas
- Department of Neurology, Hospital Universitari La Fe, Valencia, Spain
| | - A Nascimento
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - C Ortez
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - T Jaijo
- Department of Neurology, Hospital Universitari La Fe, Valencia, Spain
| | - R Arteaga
- Department of Pediatrics, Hospital Universitario Marqués de Valdecilla, Santander, Spain
| | - J Colomer
- Department of Neuromuscular Diseases, Hospital Sant Joan de Déu, Barcelona, Spain
| | - J J Vilchez
- Department of Neurology, Hospital Universitari La Fe, Valencia, Spain
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Tan JS, Ambang T, Ahmad-Annuar A, Rajahram GS, Wong KT, Goh KJ. Congenital myasthenic syndrome due to novel CHAT
mutations in an ethnic kadazandusun family. Muscle Nerve 2016; 53:822-6. [DOI: 10.1002/mus.25037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/08/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Joo-San Tan
- Division of Neurology, Department of Medicine, Faculty of Medicine; University of Malaya; Kuala Lumpur Malaysia
| | - Tomica Ambang
- Division of Neurology, Department of Medicine, Faculty of Medicine; University of Malaya; Kuala Lumpur Malaysia
| | - Azlina Ahmad-Annuar
- Department of Biomedical Science, Faculty of Medicine; University of Malaya; Kuala Lumpur Malaysia
| | - Giri Shan Rajahram
- Department of Medicine; Hospital Queen Elizabeth; Kota Kinabalu Sabah Malaysia
| | - Kum Thong Wong
- Department of Pathology, Faculty of Medicine; University of Malaya; Kuala Lumpur Malaysia
| | - Khean Jin Goh
- Division of Neurology, Department of Medicine, Faculty of Medicine; University of Malaya; Kuala Lumpur Malaysia
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Oikari S, Makkonen K, Deen AJ, Tyni I, Kärnä R, Tammi RH, Tammi MI. Hexosamine biosynthesis in keratinocytes: roles of GFAT and GNPDA enzymes in the maintenance of UDP-GlcNAc content and hyaluronan synthesis. Glycobiology 2016; 26:710-22. [PMID: 26887390 DOI: 10.1093/glycob/cww019] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/12/2016] [Indexed: 12/18/2022] Open
Abstract
UDP-N-acetylglucosamine (UDP-GlcNAc) is a glucose metabolite with pivotal functions as a key substrate for the synthesis of glycoconjugates like hyaluronan, and as a metabolic sensor that controls cell functions through O-GlcNAc modification of intracellular proteins. However, little is known about the regulation of hexosamine biosynthesis that controls UDP-GlcNAc content. Four enzymes can catalyze the crucial starting point of the pathway, conversion of fructose-6-phosphate (Fru6P) to glucosamine-6-phosphate (GlcN6P): glutamine-fructose-6-phosphate aminotransferases (GFAT1 and 2) and glucosamine-6-phosphate deaminases (GNPDA1 and 2). Using siRNA silencing, we studied the contributions of these enzymes to UDP-GlcNAc content and hyaluronan synthesis in human keratinocytes. Depletion of GFAT1 reduced the cellular pool of UDP-GlcNAc and hyaluronan synthesis, while simultaneous blocking of both GNPDA1 and GDPDA2 exerted opposite effects, indicating that in standard culture conditions keratinocyte GNPDAs mainly catalyzed the reaction from GlcN6P back to Fru6P. However, when hexosamine biosynthesis was blocked by GFAT1 siRNA, the effect by GNPDAs was reversed, now catalyzing Fru6P towards GlcN6P, likely in an attempt to maintain UDP-GlcNAc content. Silencing of these enzymes also changed the gene expression of related enzymes: GNPDA1 siRNA induced GFAT2 which was hardly measurable in these cells under standard culture conditions, GNPDA2 siRNA increased GFAT1, and GFAT1 siRNA increased the expression of hyaluronan synthase 2 (HAS2). Silencing of GFAT1 stimulated GNPDA1 and GDPDA2, and inhibited cell migration. The multiple delicate adjustments of these reactions demonstrate the importance of hexosamine biosynthesis in cellular homeostasis, known to be deranged in diseases like diabetes and cancer.
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Affiliation(s)
- Sanna Oikari
- Institutes of Biomedicine Department of Dentistry, University of Eastern Finland, Yliopistonranta 1E, PO Box 1627, Kuopio 70211, Finland
| | - Katri Makkonen
- Institutes of Biomedicine Department of Dentistry, University of Eastern Finland, Yliopistonranta 1E, PO Box 1627, Kuopio 70211, Finland
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Vrinten C, van der Zwaag AM, Weinreich SS, Scholten RJPM, Verschuuren JJGM. Ephedrine for myasthenia gravis, neonatal myasthenia and the congenital myasthenic syndromes. Cochrane Database Syst Rev 2014; 2014:CD010028. [PMID: 25515947 PMCID: PMC7387729 DOI: 10.1002/14651858.cd010028.pub2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Myasthenia is a condition in which neuromuscular transmission is affected by antibodies against neuromuscular junction components (autoimmune myasthenia gravis, MG; and neonatal myasthenia gravis, NMG) or by defects in genes for neuromuscular junction proteins (congenital myasthenic syndromes, CMSs). Clinically, some individuals seem to benefit from treatment with ephedrine, but its effects and adverse effects have not been systematically evaluated. OBJECTIVES To assess the effects and adverse effects of ephedrine in people with autoimmune MG, transient neonatal MG, and the congenital myasthenic syndromes. SEARCH METHODS On 17 November 2014, we searched the Cochrane Neuromuscular Disease Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. We also searched reference lists of articles, conference proceedings of relevant conferences, and prospective trial registers. In addition, we contacted manufacturers and researchers in the field. SELECTION CRITERIA We considered randomised controlled trials (RCTs) and quasi-RCTs comparing ephedrine as a single or add-on treatment with any other active treatment, placebo, or no treatment in adults or children with autoimmune MG, NMG, or CMSs. DATA COLLECTION AND ANALYSIS Two review authors independently assessed study design and quality, and extracted data. We contacted study authors for additional information. We collected information on adverse effects from included articles, and contacted authors. MAIN RESULTS We found no RCTs or quasi-RCTs, and therefore could not establish the effect of ephedrine on MG, NMG and CMSs. We describe the results of 53 non-randomised studies narratively in the Discussion section, including observations of endurance, muscle strength and quality of life. Effects may differ depending on the type of myasthenia. Thirty-seven studies were in participants with CMS, five in participants with MG, and in 11 the precise form of myasthenia was unknown. We found no studies for NMG. Reported adverse effects included tachycardia, sleep disturbances, nervousness, and withdrawal symptoms. AUTHORS' CONCLUSIONS There was no evidence available from RCTs or quasi-RCTs, but some observations from non-randomised studies are available. There is a need for more evidence from suitable forms of prospective RCTs, such as series of n-of-one RCTs, that use appropriate and validated outcome measures.
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Affiliation(s)
- Charlotte Vrinten
- VU University Medical CenterCommunity Genetics Section, Clinical GeneticsBS7, D450PO Box 7057AmsterdamNetherlands1007 MB
| | - Angeli M van der Zwaag
- VU University Medical CenterCommunity Genetics Section, Clinical GeneticsBS7, D450PO Box 7057AmsterdamNetherlands1007 MB
| | - Stephanie S Weinreich
- VU University Medical CenterCommunity Genetics Section, Clinical GeneticsBS7, D450PO Box 7057AmsterdamNetherlands1007 MB
| | - Rob JPM Scholten
- Julius Center for Health Sciences and Primary Care / University Medical Center UtrechtDutch Cochrane CentreRoom Str. 6.126P.O. Box 85500UtrechtNetherlands3508 GA
| | - Jan JGM Verschuuren
- Leiden University Medical CenterDepartment of NeurologyPO Box 9600LeidenNetherlands2300 RC
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Guo Y, Menezes MJ, Menezes MP, Liang J, Li D, Riley LG, Clarke NF, Andrews PI, Tian L, Webster R, Wang F, Liu X, Shen Y, Thorburn DR, Keating BJ, Engel A, Hakonarson H, Christodoulou J, Xu X. Delayed diagnosis of congenital myasthenia due to associated mitochondrial enzyme defect. Neuromuscul Disord 2014; 25:257-61. [PMID: 25557462 DOI: 10.1016/j.nmd.2014.11.017] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/15/2014] [Accepted: 11/24/2014] [Indexed: 11/18/2022]
Abstract
Clinical phenotypes of congenital myasthenic syndromes and primary mitochondrial disorders share significant overlap in their clinical presentations, leading to challenges in making the correct diagnosis. Next generation sequencing is transforming molecular diagnosis of inherited neuromuscular disorders by identifying novel disease genes and by identifying previously known genes in undiagnosed patients. This is evident in two patients who were initially suspected to have a mitochondrial myopathy, but in whom a clear diagnosis of congenital myasthenic syndromes was made through whole exome sequencing. In patient 1, whole exome sequencing revealed compound heterozygous mutations c.1228C > T (p.Arg410Trp) and c.679C > T (p.Arg227*) in collagen-like tail subunit (single strand of homotrimer) of asymmetric acetylcholinesterase (COLQ). In patient 2, in whom a deletion of exon 52 in Dystrophin gene was previously detected by multiplex ligation-dependent probe amplification, Sanger sequencing revealed an additional homozygous mutation c.1511_1513delCTT (p.Pro504Argfs*183) in docking protein7 (DOK7). These case reports highlight the need for careful diagnosis of clinically heterogeneous syndromes like congenital myasthenic syndromes, which are treatable, and for which delayed diagnosis is likely to have implications for patient health. The report also demonstrates that whole exome sequencing is an effective diagnostic tool in providing molecular diagnosis in patients with complex phenotypes.
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Affiliation(s)
- Yiran Guo
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Minal J Menezes
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia; Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
| | - Manoj P Menezes
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | | | - Dong Li
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Lisa G Riley
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Nigel F Clarke
- Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - P Ian Andrews
- Department of Neurology, Sydney Children's Hospital, Randwick, NSW, Australia
| | - Lifeng Tian
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Richard Webster
- Institute for Neuroscience and Muscle Research, The Children's Hospital at Westmead, Sydney, NSW, Australia
| | - Fengxiang Wang
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | | | | | - David R Thorburn
- Murdoch Childrens Research Institute and Victorian Clinical Genetics Services, Royal Children's Hospital, Melbourne, VIC, Australia; Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
| | - Brendan J Keating
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States; Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Human Genetics Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - Andrew Engel
- Department of Neurology, Mayo Clinic, Rochester, MN, United States
| | - Hakon Hakonarson
- The Center for Applied Genomics, The Children's Hospital of Philadelphia, Philadelphia, PA, United States; Department of Pediatrics, The Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States; Department of Human Genetics Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States
| | - John Christodoulou
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, NSW, Australia; Discipline of Paediatrics & Child Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia; Discipline of Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, NSW, Australia.
| | - Xun Xu
- BGI-Shenzhen, Shenzhen 518083, China; The Guangdong Enterprise Key Laboratory of Human Disease Genomics, BGI-Shenzhen, Shenzhen, China
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Das AS, Agamanolis DP, Cohen BH. Use of next-generation sequencing as a diagnostic tool for congenital myasthenic syndrome. Pediatr Neurol 2014; 51:717-20. [PMID: 25194721 DOI: 10.1016/j.pediatrneurol.2014.07.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Revised: 07/29/2014] [Accepted: 07/31/2014] [Indexed: 11/30/2022]
Abstract
BACKGROUND The clinical presentation of congenital myasthenic syndromes is similar to many other neuromuscular disorders of infancy, and with 12 known discrete genetic forms of congenital myasthenic syndromes, both the diagnosis and treatment decisions present clinical challenges. PATIENT DESCRIPTION We report a 20-month-old boy with rapsyn deficiency. At birth, he presented with a weak cry, hypotonia, joint contractures, and facial deformity. Because of respiratory difficulty associated with muscle fatigue, he spent a total of 71 days in the neonatal intensive care unit and 47 days in the pediatric intensive care unit. Imaging study results were normal, along with a battery of metabolic tests and electrodiagnostic studies. A limited genetic evaluation for reversible cytochrome c oxidase deficiency was negative, as was the oligonucleotide microarray. A muscle biopsy demonstrated myofiber atrophy in a pattern consistent with early denervation. Based on nonspecific and nondiagnostic results, whole-exome (next generation) sequencing was performed. This study identified two confirmed pathogenic mutations in the RAPSN gene that are associated with congenital myasthenic syndrome (OMIM 608931). The patient was treated with pyridostigmine at 16 months of age, which resulted in a dramatic improvement in muscle tone and strength and a steady resolution of joint contractures. Four months after treatment was initiated, he was beginning to bear weight and was able to sit unsupported and vocalize full words. CONCLUSIONS This patient serves to highlight next-generation sequencing as an important diagnostic tool that can result in life-saving treatment.
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Affiliation(s)
- Alvin S Das
- Northeast Ohio Medical University, Rootstown, Ohio
| | - Dimitri P Agamanolis
- Department of Pathology and Laboratory Medicine, Akron Children's Hospital, Akron, Ohio; Department of Pathology, Northeast Ohio Medical University, Rootstown, Ohio
| | - Bruce H Cohen
- Division of Neurology, NeuroDevelopmental Science Center, Akron Children's Hospital, Akron, Ohio; Department of Pediatrics, Northeast Ohio Medical University, Rootstown, Ohio.
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Heller R, Hoffmann K. Genetische Diagnostik und Beratung bei Arthrogryposis. MED GENET-BERLIN 2013. [DOI: 10.1007/s11825-013-0411-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Zusammenfassung
Es werden wichtige Probleme in der Diagnostik bei Patienten mit Arthrogryposis dargestellt und Definitionen eingeführt. Danach werden praktische Ansätze für die Diagnostik und humangenetische Betreuung vorgeschlagen.
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Affiliation(s)
- R. Heller
- Aff1 grid.411097.a 000000008852305X Institut für Humangenetik Uniklinik Köln Kerpener Str. 34 50931 Köln Deutschland
| | - K. Hoffmann
- Aff2 grid.9018.0 0000000106792801 Institut für Humangenetik Martin-Luther-Universität Halle Wittenberg Magdeburger Str. 2 06112 Halle (Saale) Deutschland
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Lorenzoni PJ, Scola RH, Kay CSK, Filla L, Miranda APP, Pinheiro JMR, Chaouch A, Lochmüller H, Werneck LC. Salbutamol therapy in congenital myasthenic syndrome due to DOK7 mutation. J Neurol Sci 2013; 331:155-7. [PMID: 23790237 DOI: 10.1016/j.jns.2013.05.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 05/03/2013] [Accepted: 05/10/2013] [Indexed: 02/04/2023]
Abstract
INTRODUCTION Salbutamol is a selective B2-adrenergic agonist, which has previously been described to be associated with partial improvement of myasthenia gravis and congenital myasthenic syndromes (CMS). In this study, we analyzed the effect of salbutamol in five patients with Dok-7 CMS. METHODS We studied 5 patients (2 male and 3 female), with a mean age of 27±11.06 years, who harbored c.1124_1127dupTGCC, p.G64R and/or p.S45L mutations in DOK7 gene. Salbutamol was given at a dose of 2mg three times daily (6 mg/day) to all patients. The response was assessed by QMG score at baseline, 3, 6, 9 and 12 months; ADL-MG score and 6 minute walk test at baseline and after 12 months during follow-up clinic visits. Side effect profile of salbutamol was also evaluated. RESULTS We noted an increasingly positive response as measured by the QMG score after 3 months of salbutamol treatment. Improvement in specific subcomponents of the QMG score such as leg outstretched in 45° supine was most marked. In ADL-MG scores and 6 minute walk test, comparison between baseline and after 12 months revealed a clear beneficial response. Salbutamol was well tolerated in all patients. CONCLUSIONS Salbutamol is an effective treatment in Dok-7 CMS. This study provides class IV evidence that salbutamol given at a dose 6 mg/day improves function as measured by the QMG score, ADL-MG score and 6 minute walk test.
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Affiliation(s)
- Paulo J Lorenzoni
- Neurology Division, Internal Medicine Department, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, PR, Brazil
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Houlden H. Defective N-linked protein glycosylation pathway in congenital myasthenic syndromes. Brain 2013; 136:692-5. [PMID: 23436500 DOI: 10.1093/brain/awt042] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zoltowska K, Webster R, Finlayson S, Maxwell S, Cossins J, Müller J, Lochmüller H, Beeson D. Mutations in GFPT1 that underlie limb-girdle congenital myasthenic syndrome result in reduced cell-surface expression of muscle AChR. Hum Mol Genet 2013; 22:2905-13. [DOI: 10.1093/hmg/ddt145] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Karmouch J, Dobbertin A, Sigoillot S, Legay C. Developmental consequences of the ColQ/MuSK interactions. Chem Biol Interact 2012; 203:287-91. [PMID: 23089045 DOI: 10.1016/j.cbi.2012.10.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/09/2012] [Accepted: 10/11/2012] [Indexed: 10/27/2022]
Abstract
CollagenQ (ColQ) is a specific collagen that anchors acetylcholinesterase (AChE) in the synaptic basal lamina of the neuromuscular junction (NMJ). Over 30 mutations in the COLQ gene have been identified that are responsible for a congenital myasthenic syndrome with AChE deficiency, highlighting the importance of this collagen in the physiology of the NMJ. The anchoring of AChE at the synapse requires the interaction of ColQ with MuSK (Muscle-Specific Kinase), a tyrosine kinase expressed on the muscle membrane that is necessary for the formation and the maintenance of the NMJ. MuSK forms with its co-receptor LRP4, a member of the Low-density Related Protein family, a receptor complex for agrin and Wnts, representing the core system from which the postsynaptic domain is built, the growth cone attracted and the presynaptic element instructed for some aspects of its differentiation. Therefore, the discovery that ColQ binds to MuSK prompted us to study a possible regulatory function of ColQ during NMJ development. In this review, after a brief survey on ColQ, we summarize our recent data demonstrating that ColQ, in addition to its anchoring role, exerts signaling functions and controls some aspects of postsynaptic differentiation such as the clustering of acetylcholine receptors. Our results also strengthen the hypothesis that the defects observed in synaptic congenital myasthenic syndromes might be linked, at least in part, to alterations of ColQ signaling functions and not only to AChE deficiency. Finally, we discuss future research directions to understand how ColQ may modulate the action of the other ligands of the MuSK/LRP4 complex and cooperate with them to coordinate the different steps of NMJ formation and maintenance.
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Affiliation(s)
- Jennifer Karmouch
- CESEM, CNRS UMR 8194, University of Paris Descartes, 45 rue des Saints-Pères, 75006 Paris Cedex, France
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