Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort Study

Introduction: Congenital myasthenic syndromes (CMS) refer to a heterogenic group of neuromuscular transmission disorders. CMS-subtypes are diverse regarding exercise intolerance and muscular weakness, varying from mild symptoms to life-limiting forms with neonatal onset. Long-term follow-up studies...

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Main Authors: Adela Della Marina, Eva Wibbeler, Angela Abicht, Heike Kölbel, Hanns Lochmüller, Andreas Roos, Ulrike Schara
Format: Article
Language:English
Published: Frontiers Media S.A. 2020-12-01
Series:Frontiers in Human Neuroscience
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fnhum.2020.560860/full
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author Adela Della Marina
Eva Wibbeler
Angela Abicht
Angela Abicht
Heike Kölbel
Hanns Lochmüller
Hanns Lochmüller
Hanns Lochmüller
Andreas Roos
Ulrike Schara
author_facet Adela Della Marina
Eva Wibbeler
Angela Abicht
Angela Abicht
Heike Kölbel
Hanns Lochmüller
Hanns Lochmüller
Hanns Lochmüller
Andreas Roos
Ulrike Schara
author_sort Adela Della Marina
collection DOAJ
description Introduction: Congenital myasthenic syndromes (CMS) refer to a heterogenic group of neuromuscular transmission disorders. CMS-subtypes are diverse regarding exercise intolerance and muscular weakness, varying from mild symptoms to life-limiting forms with neonatal onset. Long-term follow-up studies on disease progression and treatment-response in pediatric patients are rare.Patients and Methods: We analyzed retrospective clinical and medication data in a cohort of 32 CMS-patients including the application of a standardized, not yet validated test (CMS-ST) to examine muscular strength and endurance in 21 patients at the last follow-up. Findings obtained in our cohort were compared with long-term follow-up studies of (adult) CMS-cohorts from the literature by considering the underlying molecular mechanisms. Outcomes of CMS-ST were compared to results of normal clinical assessment.Results: Thirty-two pediatric patients with defects in eight different CMS-genes were followed by a median time of 12.8 years. Fifty-nine percentage of patients manifested with first symptoms as neonates, 35% as infants. While 53% of patients presented a reduced walking distance, 34% were wheelchair-bound. Even under adequate therapy with pyridostigmine (PS) and 3,4-diaminopyridine, CHAT-mutations led to the progression of muscular weakness partly in combination with persistent respiratory and bulbar symptoms. RAPSN, CHRND, and CHRNB1 patients with neonatal manifestation, early respiratory problems, and bulbar symptoms showed a good and maintained treatment response. CHAT and CHRNE patients required higher PS dosages, whereas RAPSN patients needed a lower mean dosage at the last follow-up. The benefits of short-term medication and long-term progression of symptoms were highly dependent on the specific genetic defect. CMS-ST was carried out in 17/21 patients, determined affected muscle groups including bulbar and ocular symptoms, some of which were not reported by the patients.Conclusions: Our findings and comparison with the literature- suggest a better treatment-response and less severe progression of symptoms present in patients suffering from mutations in CMS-genes directly associated with receptor deficiency, while patients with defects leading to synaptopathy and presynaptic defects tend to have worse outcomes. Assessment of affected muscular groups and clinical symptoms by CMS-ST may be a useful tool for optimal therapeutic management of the patients, especially for future clinical studies.
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spelling doaj.art-e5e9cc9349194bf980568c61bf418da52022-12-21T18:14:30ZengFrontiers Media S.A.Frontiers in Human Neuroscience1662-51612020-12-011410.3389/fnhum.2020.560860560860Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort StudyAdela Della Marina0Eva Wibbeler1Angela Abicht2Angela Abicht3Heike Kölbel4Hanns Lochmüller5Hanns Lochmüller6Hanns Lochmüller7Andreas Roos8Ulrike Schara9Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children’s Hospital Essen, University Duisburg-Essen, Essen, GermanyChildren’s Hospital, University Medical Center Hamburg Eppendorf, Hamburg, GermanyMedical Genetic Center Munich, Munich, GermanyFriedrich-Baur Institute, Ludwig Maximilian University, Munich, GermanyDepartment of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children’s Hospital Essen, University Duisburg-Essen, Essen, GermanyChildren’s Hospital of Eastern Ontario Research Institute, Division of Neurology, Department of Medicine, The Ottawa Hospital, Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, CanadaDepartment of Neuropediatrics and Muscle Disorders, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, GermanyCentro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, SpainDepartment of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children’s Hospital Essen, University Duisburg-Essen, Essen, GermanyDepartment of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children’s Hospital Essen, University Duisburg-Essen, Essen, GermanyIntroduction: Congenital myasthenic syndromes (CMS) refer to a heterogenic group of neuromuscular transmission disorders. CMS-subtypes are diverse regarding exercise intolerance and muscular weakness, varying from mild symptoms to life-limiting forms with neonatal onset. Long-term follow-up studies on disease progression and treatment-response in pediatric patients are rare.Patients and Methods: We analyzed retrospective clinical and medication data in a cohort of 32 CMS-patients including the application of a standardized, not yet validated test (CMS-ST) to examine muscular strength and endurance in 21 patients at the last follow-up. Findings obtained in our cohort were compared with long-term follow-up studies of (adult) CMS-cohorts from the literature by considering the underlying molecular mechanisms. Outcomes of CMS-ST were compared to results of normal clinical assessment.Results: Thirty-two pediatric patients with defects in eight different CMS-genes were followed by a median time of 12.8 years. Fifty-nine percentage of patients manifested with first symptoms as neonates, 35% as infants. While 53% of patients presented a reduced walking distance, 34% were wheelchair-bound. Even under adequate therapy with pyridostigmine (PS) and 3,4-diaminopyridine, CHAT-mutations led to the progression of muscular weakness partly in combination with persistent respiratory and bulbar symptoms. RAPSN, CHRND, and CHRNB1 patients with neonatal manifestation, early respiratory problems, and bulbar symptoms showed a good and maintained treatment response. CHAT and CHRNE patients required higher PS dosages, whereas RAPSN patients needed a lower mean dosage at the last follow-up. The benefits of short-term medication and long-term progression of symptoms were highly dependent on the specific genetic defect. CMS-ST was carried out in 17/21 patients, determined affected muscle groups including bulbar and ocular symptoms, some of which were not reported by the patients.Conclusions: Our findings and comparison with the literature- suggest a better treatment-response and less severe progression of symptoms present in patients suffering from mutations in CMS-genes directly associated with receptor deficiency, while patients with defects leading to synaptopathy and presynaptic defects tend to have worse outcomes. Assessment of affected muscular groups and clinical symptoms by CMS-ST may be a useful tool for optimal therapeutic management of the patients, especially for future clinical studies.https://www.frontiersin.org/articles/10.3389/fnhum.2020.560860/fullcongenital myasthenic syndromeneuromuscular transmissiontherapylong-term outcomestandardized testing
spellingShingle Adela Della Marina
Eva Wibbeler
Angela Abicht
Angela Abicht
Heike Kölbel
Hanns Lochmüller
Hanns Lochmüller
Hanns Lochmüller
Andreas Roos
Ulrike Schara
Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort Study
Frontiers in Human Neuroscience
congenital myasthenic syndrome
neuromuscular transmission
therapy
long-term outcome
standardized testing
title Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort Study
title_full Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort Study
title_fullStr Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort Study
title_full_unstemmed Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort Study
title_short Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes—A Retrospective Single Centre Cohort Study
title_sort long term follow up on pediatric cases with congenital myasthenic syndromes a retrospective single centre cohort study
topic congenital myasthenic syndrome
neuromuscular transmission
therapy
long-term outcome
standardized testing
url https://www.frontiersin.org/articles/10.3389/fnhum.2020.560860/full
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