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Smeets N, Gheldof A, Dequeker B, Poleur M, Maldonado Slootjes S, Van Parijs V, Deconinck N, Dontaine P, Alonso-Jimenez A, De Bleecker J, De Ridder W, Herdewyn S, Paquay S, Vanlander A, De Waele L, Peirens G, Beysen D, Claeys KG, Dubuisson N, Hansen I, Remiche G, Seneca S, Bissay V, Régal L. Congenital Myasthenic Syndromes in Belgium: Genetic and Clinical Characterization of Pediatric and Adult Patients. Pediatr Neurol 2024; 158:57-65. [PMID: 38964204 DOI: 10.1016/j.pediatrneurol.2024.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2024] [Revised: 05/29/2024] [Accepted: 06/05/2024] [Indexed: 07/06/2024]
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) are a group of genetic disorders characterized by impaired neuromuscular transmission. CMS typically present at a young age with fatigable muscle weakness, often with an abnormal response after repetitive nerve stimulation (RNS). Pharmacologic treatment can improve symptoms, depending on the underlying defect. Prevalence is likely underestimated. This study reports on patients with CMS followed in Belgium in 2022. METHODS Data were gathered retrospectively from the medical charts. Only likely pathogenic and pathogenic variants were included in the analysis. RESULTS We identified 37 patients, resulting in an estimated prevalence of 3.19 per 1,000,000. The patients harbored pathogenic variants in CHRNE, RAPSN, DOK7, PREPL, CHRNB1, CHRNG, COLQ, MUSK, CHRND, GFPT1, and GMPPB. CHRNE was the most commonly affected gene. Most patients showed disease onset at birth, during infancy, or during childhood. Symptom onset was at adult age in seven patients, caused by variants in CHRNE, DOK7, MUSK, CHRND, and GMPPB. Severity and distribution of weakness varied, as did the presence of respiratory involvement, feeding problems, and extraneuromuscular manifestations. RNS was performed in 23 patients of whom 18 demonstrated a pathologic decrement. Most treatment responses were predictable based on the genotype. CONCLUSIONS This is the first pooled characterization of patients with CMS in Belgium. We broaden the phenotypical spectrum of pathogenic variants in CHRNE with adult-onset CMS. Systematically documenting larger cohorts of patients with CMS can aid in better clinical characterization and earlier recognition of this rare disease. We emphasize the importance of establishing a molecular genetic diagnosis to tailor treatment choices.
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Affiliation(s)
- Nathalie Smeets
- Child Neurology Unit, Department of Pediatrics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium.
| | - Alexander Gheldof
- Center of Medical Genetics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Bart Dequeker
- Center of Medical Genetics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Margaux Poleur
- University Department of Neurology, Citadelle Hospital of Liège, Liège, Belgium
| | | | - Vinciane Van Parijs
- Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Nicolas Deconinck
- Department of Pediatric Neurology, Queen Fabiola Children's University Hospital, Université Libre De Bruxelles, Brussels, Belgium
| | - Pauline Dontaine
- Department of Pediatric Neurology, Queen Fabiola Children's University Hospital, Université Libre De Bruxelles, Brussels, Belgium
| | - Alicia Alonso-Jimenez
- Department of Neurology, University of Antwerp, Antwerp University Hospital, Antwerp, Belgium
| | - Jan De Bleecker
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - Willem De Ridder
- Department of Neurology, University of Antwerp, Antwerp University Hospital, Antwerp, Belgium
| | - Sarah Herdewyn
- Department of Neurology, Ghent University Hospital, Ghent, Belgium
| | - Stéphanie Paquay
- Department of Neuropediatrics, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Arnaud Vanlander
- Department of Pediatric Neurology and Metabolic Diseases, Ghent University Hospital, Ghent, Belgium
| | - Liesbeth De Waele
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium; Department of Pediatric Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Geertrui Peirens
- Department of Development and Regeneration, KU Leuven, Leuven, Belgium; Department of Pediatric Neurology, University Hospitals Leuven, Leuven, Belgium
| | - Diane Beysen
- Department of Pediatric Neurology, University of Antwerp, Antwerp University Hospital, Antwerp, Belgium
| | - Kristl G Claeys
- Department of Neurology, University Hospitals Leuven, Leuven, Belgium; Laboratory for Muscle Diseases and Neuropathies, Department of Neurosciences, KU Leuven, Leuven Brain Institute (LBI), Leuven, Belgium
| | - Nicolas Dubuisson
- Department of Neurology, Cliniques Universitaires Saint-Luc, Brussels, Belgium
| | - Isabelle Hansen
- Department of Neurology, University of Liège, Centre Hospitalier Universitaire de Liège, Liège, Belgium
| | - Gauthier Remiche
- Department of Neurology, Hôpital Universitaire de Bruxelles - Hôpital Erasme, Université Libre de Bruxelles, Brussels, Belgium
| | - Sara Seneca
- Center of Medical Genetics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Véronique Bissay
- NEUR Research Group and Department of Neurology, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
| | - Luc Régal
- Child Neurology Unit, Department of Pediatrics, Vrije Universiteit Brussel, Universitair Ziekenhuis Brussel, Brussels, Belgium
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Zhang Z, Zhang X, Xue H, Chu L, Hu L, Bi X, Zhu P, Zhang D, Chen J, Cui X, Kong L, Liang B, Wu X. Preimplantation genetic testing as a means of preventing hereditary congenital myasthenic syndrome caused by RAPSN. Mol Genet Genomic Med 2024; 12:e2409. [PMID: 38511267 PMCID: PMC10955331 DOI: 10.1002/mgg3.2409] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 01/30/2024] [Accepted: 02/13/2024] [Indexed: 03/22/2024] Open
Abstract
BACKGROUND Congenital myasthenic syndrome is a heterogeneous group of inherited neuromuscular transmission disorders. Variants in RAPSN are a common cause of CMS, accounting for approximately 14%-27% of all CMS cases. Whether preimplantation genetic testing for monogenic disease (PGT-M) could be used to prevent the potential birth of CMS-affected children is unclear. METHODS Application of WES (whole-exome sequencing) for carrier testing and guidance for the PGT-M in the absence of a genetically characterized index patient as well as assisted reproductive technology were employed to prevent the occurrence of birth defects in subsequent pregnancy. The clinical phenotypes of stillborn fetuses were also assessed. RESULTS The family carried two likely pathogenic variants in RAPSN(NM_005055.5): c.133G>A (p.V45M) and c.280G>A (p.E94K). And the potential birth of CMS-affected child was successfully prevented, allowing the family to have offspring devoid of disease-associated variants and exhibiting a normal phenotype. CONCLUSION This report constitutes the first documented case of achieving a CMS-free offspring through PGT-M in a CMS-affected family. By broadening the known variant spectrum of RAPSN in the Chinese population, our findings underscore the feasibility and effectiveness of PGT-M for preventing CMS, offering valuable insights for similarly affected families.
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Affiliation(s)
- Zhiping Zhang
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | - Xueluo Zhang
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | - Huiqin Xue
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | - Liming Chu
- Basecare Medical Device Co., LtdSuzhouChina
| | - Lina Hu
- Basecare Medical Device Co., LtdSuzhouChina
| | - Xingyu Bi
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | - Pengfei Zhu
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | - Dongdong Zhang
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | - Jiayao Chen
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | - Xiangrong Cui
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
| | | | - Bo Liang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, School of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghaiChina
| | - Xueqing Wu
- Center of Reproductive MedicineAffiliated Children's Hospital of Shanxi & Women Health Center of Shanxi Medicine UniversityTaiyuanShanxiChina
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Kouyoumdjian JA, Estephan EDP. Electrophysiological evaluation of the neuromuscular junction: a brief review. ARQUIVOS DE NEURO-PSIQUIATRIA 2023; 81:1040-1052. [PMID: 38157872 PMCID: PMC10756823 DOI: 10.1055/s-0043-1777749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Accepted: 11/17/2023] [Indexed: 01/03/2024]
Abstract
The nerve terminal and muscle membrane compose the neuromuscular junction. After opening the voltage-gated calcium channels, action potentials from the motor axons provoke a cascade for the acetylcholine release from synaptic vesicles to the synaptic cleft, where it binds to its receptor at the muscle membrane for depolarization. Low amplitude compound muscle action potential typically presents in presynaptic disorders, increasing by more than 100% after a 10-second effort in the Lambert-Eaton myasthenic syndrome and less in botulism. Needle electromyography may show myopathic motor unit action potentials and morphological instability ("jiggle") due to impulse blocking. Low-frequency repetitive nerve stimulation (RNS) is helpful in postsynaptic disorders, such as myasthenia gravis and most congenital myasthenic syndromes, where the number of functioning acetylcholine receptors is reduced. Low-frequency RNS with a decrement >10% is abnormal when comparing the 4th to the first compound muscle action potential amplitude. High-frequency RNS is helpful in presynaptic disorders like Lambert-Eaton myasthenic syndrome, botulism, and some rare congenital myasthenic syndromes. The high-frequency RNS releases more calcium, increasing the acetylcholine with a compound muscle action potential increment. Concentric needle records apparent single-fiber action potentials (spikes). A voluntary activation measures the jitter between spikes from two endplates. An electrical activation measures the jitter of one spike (one endplate). The jitter is the most sensitive test for detecting a neuromuscular junction dysfunction. Most neuromuscular junction disorders are responsive to treatment.
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Affiliation(s)
- João Aris Kouyoumdjian
- Faculdade de Medicina de São José do Rio Preto, Departamento de Ciências Neurológicas, Psiquiatria e Psicologia Médica, São José do Rio Preto SP, Brazil.
| | - Eduardo de Paula Estephan
- Faculdade de Medicina de São José do Rio Preto, Departamento de Ciências Neurológicas, Psiquiatria e Psicologia Médica, São José do Rio Preto SP, Brazil.
- Universidade de São Paulo, Departamento de Neurologia, São Paulo SP, Brazil.
- Faculdade de Medicina Santa Marcelina, São Paulo SP, Brazil.
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Ohno K, Ohkawara B, Shen XM, Selcen D, Engel AG. Clinical and Pathologic Features of Congenital Myasthenic Syndromes Caused by 35 Genes-A Comprehensive Review. Int J Mol Sci 2023; 24:ijms24043730. [PMID: 36835142 PMCID: PMC9961056 DOI: 10.3390/ijms24043730] [Citation(s) in RCA: 36] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 02/09/2023] [Accepted: 02/09/2023] [Indexed: 02/16/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are a heterogeneous group of disorders characterized by impaired neuromuscular signal transmission due to germline pathogenic variants in genes expressed at the neuromuscular junction (NMJ). A total of 35 genes have been reported in CMS (AGRN, ALG14, ALG2, CHAT, CHD8, CHRNA1, CHRNB1, CHRND, CHRNE, CHRNG, COL13A1, COLQ, DOK7, DPAGT1, GFPT1, GMPPB, LAMA5, LAMB2, LRP4, MUSK, MYO9A, PLEC, PREPL, PURA, RAPSN, RPH3A, SCN4A, SLC18A3, SLC25A1, SLC5A7, SNAP25, SYT2, TOR1AIP1, UNC13A, VAMP1). The 35 genes can be classified into 14 groups according to the pathomechanical, clinical, and therapeutic features of CMS patients. Measurement of compound muscle action potentials elicited by repetitive nerve stimulation is required to diagnose CMS. Clinical and electrophysiological features are not sufficient to identify a defective molecule, and genetic studies are always required for accurate diagnosis. From a pharmacological point of view, cholinesterase inhibitors are effective in most groups of CMS, but are contraindicated in some groups of CMS. Similarly, ephedrine, salbutamol (albuterol), amifampridine are effective in most but not all groups of CMS. This review extensively covers pathomechanical and clinical features of CMS by citing 442 relevant articles.
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Affiliation(s)
- Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Correspondence: (K.O.); (A.G.E.)
| | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Xin-Ming Shen
- Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - Duygu Selcen
- Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA
| | - Andrew G. Engel
- Department of Neurology and Neuromuscular Research Laboratory, Mayo Clinic, Rochester, MN 55905, USA
- Correspondence: (K.O.); (A.G.E.)
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Estephan EDP, Baima JPS, Zambon AA. Myasthenia gravis in clinical practice. ARQUIVOS DE NEURO-PSIQUIATRIA 2022; 80:257-265. [PMID: 35976295 PMCID: PMC9491427 DOI: 10.1590/0004-282x-anp-2022-s105] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 04/29/2022] [Indexed: 05/29/2023]
Abstract
BACKGROUND Myasthenia gravis is largely a treatable disease, but it can result in significant morbidity and even mortality, which can usually be avoided, or at least mitigated, with timely diagnosis and appropriate treatment of the disease. Objective: this review aims to summarize the main practical aspects of the diagnostic approach, treatment and care of myasthenic patients. METHODS The authors performed a non-systematic critical review summarizing the main practical aspects of myasthenia gravis. RESULTS Most patients with myasthenia have autoantibodies targeted at acetylcholine receptors or, less commonly, muscle-specific kinase - MuSK. Electrophysiology plays an important role in the diagnosis of neuromuscular junction dysfunction. The central clinical manifestation of myasthenia gravis is fatigable muscle weakness, which can affect eye, bulbar, respiratory, and limb muscles. With rare exceptions, patients have a good response to symptomatic treatment, but corticosteroids and/or immunosuppressants are usually also necessary to obtain good control of the manifestations of the disease. CONCLUSION Knowledge of the peculiar aspects of their clinical and electrophysiological presentations is important for the diagnosis. Likewise, specific treatment and response time to each drug are crucial for proper care.
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Affiliation(s)
- Eduardo de Paula Estephan
- Universidade de São Paulo, Faculdade de Medicina, Departamento de Neurologia, São Paulo SP, Brazil
- Fundação Faculdade Regional de Medicina de São José do Rio Preto, Hospital de Base, Departamento de Neurologia, São José do Rio Preto SP, Brazil
- Faculdade de Medicina Santa Marcelina, São Paulo SP, Brazil
| | - José Pedro Soares Baima
- Universidade de São Paulo, Faculdade de Medicina, Departamento de Neurologia, São Paulo SP, Brazil
| | - Antonio Alberto Zambon
- Universidade de São Paulo, Faculdade de Medicina, Departamento de Neurologia, São Paulo SP, Brazil
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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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7
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Estephan EP, Zambon AA, Thompson R, Polavarapu K, Jomaa D, Töpf A, Helito PVP, Heise CO, Moreno CAM, Silva AMS, Kouyoumdjian JA, Morita MDP, Reed UC, Lochmüller H, Zanoteli E. Congenital myasthenic syndrome: Correlation between clinical features and molecular diagnosis. Eur J Neurol 2021; 29:833-842. [PMID: 34749429 DOI: 10.1111/ene.15173] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/01/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To present phenotype features of a large cohort of congenital myasthenic syndromes (CMS) and correlate them with their molecular diagnosis. METHODS Suspected CMS patients were divided into three groups: group A (limb, bulbar or axial weakness, with or without ocular impairment, and all the following: clinical fatigability, electrophysiology compatible with neuromuscular junction involvement and anticholinesterase agents response), group B (limb, bulbar or axial weakness, with or without ocular impairment, and at least one of additional characteristics noted in group A) and group C (pure ocular syndrome). Individual clinical findings and the clinical groups were compared between the group with a confirmed molecular diagnosis of CMS and the group without molecular diagnosis or with a non-CMS molecular diagnosis. RESULTS Seventy-nine patients (68 families) were included in the cohort: 48 in group A, 23 in group B and 8 in group C. Fifty-one were considered confirmed CMS (30 CHRNE, 5 RAPSN, 4 COL13A1, 3 DOK7, 3 COLQ, 2 GFPT1, 1 CHAT, 1 SCN4A, 1 GMPPB, 1 CHRNA1), 7 probable CMS, 5 non-CMS and 16 unsolved. The chance of a confirmed molecular diagnosis of CMS was significantly higher for group A and lower for group C. Some individual clinical features, alterations on biopsy and electrophysiology enhanced specificity for CMS. Muscle imaging showed at least mild alterations in the majority of confirmed cases, with preferential involvement of soleus, especially in CHRNE CMS. CONCLUSIONS Stricter clinical criteria increase the chance of confirming a CMS diagnosis, but may lose sensitivity, especially for some specific genes.
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Affiliation(s)
- Eduardo P Estephan
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Sao Paulo, Brazil.,Department of Neurology, Hospital Santa Marcelina, Sao Paulo, Brazil.,Department of Medical Clinic, Faculdade de Medicina Santa Marcelina (FASM), Sao Paulo, Brazil
| | - Antonio A Zambon
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Sao Paulo, Brazil
| | - Rachel Thompson
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Kiran Polavarapu
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Danny Jomaa
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Queen's University School of Medicine, Kingston, ON, Canada
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Translational and Clinical Research Institute, University of Newcastle, Newcastle upon Tyne, UK
| | - Paulo V P Helito
- Department of Radiology, Hospital das Clínicas (HCFMUSP), Instituto de Ortopedia (IOT), Sao Paulo, Brazil
| | - Carlos O Heise
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Sao Paulo, Brazil
| | - Cristiane A M Moreno
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Sao Paulo, Brazil.,Department of Neurology, Hospital Santa Marcelina, Sao Paulo, Brazil.,Department of Medical Clinic, Faculdade de Medicina Santa Marcelina (FASM), Sao Paulo, Brazil
| | - André M S Silva
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Sao Paulo, Brazil
| | - Joao A Kouyoumdjian
- Faculdade Estadual de Medicina de Sao Jose do Rio Preto (FAMERP), Sao Jose do Rio Preto, Brazil
| | - Maria da Penha Morita
- Faculdade Estadual de Medicina de Sao Jose do Rio Preto (FAMERP), Sao Jose do Rio Preto, Brazil
| | - Umbertina C Reed
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Sao Paulo, Brazil
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada.,Department of Medicine, Ottawa Research Institute, Ottawa, ON, Canada.,Department of Neuropediatrics and Muscle Disorders, Faculty of Medicine, University Medical Center Freiburg, Freiburg, Germany.,Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Edmar Zanoteli
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Sao Paulo, Brazil
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8
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Generation and characterization of an induced pluripotent stem cell line SDQLCHi018-A from a congenital myasthenic syndrome patient carrying compound heterozygote mutations in RAPSN gene. Stem Cell Res 2021; 51:102160. [PMID: 33465529 DOI: 10.1016/j.scr.2021.102160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/27/2020] [Accepted: 01/03/2021] [Indexed: 11/22/2022] Open
Abstract
Mutations in RAPSN are an important cause of congenital myasthenic syndrome (CMS). In this study, we generated an induced pluripotent stem cell line (iPSC) derived from a 14-day-old male CMS patient carrying compound heterozygote mutations (c.532-2A > G and c.264C > A/p.Asn88Lys) in RAPSN gene. The established iPSC line harboring the original mutations, possessing a normal karyotype, is able to differentiate into all three germ layers in vitro and expresses pluripotency markers.
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Della Marina A, Wibbeler E, Abicht A, Kölbel H, Lochmüller H, Roos A, Schara U. Long Term Follow-Up on Pediatric Cases With Congenital Myasthenic Syndromes-A Retrospective Single Centre Cohort Study. Front Hum Neurosci 2020; 14:560860. [PMID: 33364925 PMCID: PMC7750519 DOI: 10.3389/fnhum.2020.560860] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 11/16/2020] [Indexed: 02/01/2023] Open
Abstract
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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Affiliation(s)
- Adela Della Marina
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children's Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Eva Wibbeler
- Children's Hospital, University Medical Center Hamburg Eppendorf, Hamburg, Germany
| | - Angela Abicht
- Medical Genetic Center Munich, Munich, Germany.,Friedrich-Baur Institute, Ludwig Maximilian University, Munich, Germany
| | - Heike Kölbel
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children's Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Hanns Lochmüller
- Children'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, Canada.,Department of Neuropediatrics and Muscle Disorders, Faculty of Medicine, Medical Center-University of Freiburg, Freiburg, Germany.,Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Andreas Roos
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children's Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Ulrike Schara
- Department of Neuropediatrics, Developmental Neurology and Social Pediatrics, University Children's Hospital Essen, University Duisburg-Essen, Essen, Germany
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Caldas VM, Heise CO, Kouyoumdjian JA, Zambon AA, Silva AMS, Estephan EDP, Zanoteli E. Electrophysiological study of neuromuscular junction in congenital myasthenic syndromes, congenital myopathies, and chronic progressive external ophthalmoplegia. Neuromuscul Disord 2020; 30:897-903. [PMID: 33121830 DOI: 10.1016/j.nmd.2020.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/05/2020] [Accepted: 10/07/2020] [Indexed: 11/19/2022]
Abstract
This study was designed to analyze the sensitivity, specificity, and accuracy of jitter parameters combined with repetitive nerve stimulation (RNS) in congenital myasthenic syndrome (CMS), chronic progressive external ophthalmoplegia (CPEO), and congenital myopathies (CM). Jitter was obtained with a concentric needle electrode during voluntary activation of the Orbicularis Oculi muscle in CMS (n = 21), CPEO (n = 20), and CM (n = 18) patients and in controls (n = 14). RNS (3 Hz) was performed in six different muscles for all patients (Abductor Digiti Minimi, Tibialis Anterior, upper Trapezius, Deltoideus, Orbicularis Oculi, and Nasalis). RNS was abnormal in 90.5% of CMS patients and in only one CM patient. Jitter was abnormal in 95.2% of CMS, 20% of CPEO, and 11.1% of CM patients. No patient with CPEO or CM presented a mean jitter higher than 53.6 µs or more than 30% abnormal individual jitter (> 45 µs). No patient with CPEO or CM and mild abnormal jitter values presented an abnormal decrement. Jitter and RNS assessment are valuable tools for diagnosing neuromuscular transmission abnormalities in CMS patients. A mean jitter value above 53.6 µs or the presence of more than 30% abnormal individual jitter (> 45 µs) strongly suggests CMS compared with CPEO and CM.
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Affiliation(s)
- Vitor Marques Caldas
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Dr. Enéas Carvalho Aguiar 255, 05403-900 São Paulo SP, Brazil
| | - Carlos Otto Heise
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Dr. Enéas Carvalho Aguiar 255, 05403-900 São Paulo SP, Brazil
| | - João Aris Kouyoumdjian
- Laboratório de Investigação Neuromuscular, Faculdade Estadual de Medicina de São Jose do Rio Preto (FAMERP), São Jose do Rio Preto, SP, Brazil
| | - Antônio Alberto Zambon
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Dr. Enéas Carvalho Aguiar 255, 05403-900 São Paulo SP, Brazil
| | - André Macedo Serafim Silva
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Dr. Enéas Carvalho Aguiar 255, 05403-900 São Paulo SP, Brazil
| | - Eduardo de Paula Estephan
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Dr. Enéas Carvalho Aguiar 255, 05403-900 São Paulo SP, Brazil; Department of Medicine, Faculdade Santa Marcelina, São Paulo, Brazil
| | - Edmar Zanoteli
- Department of Neurology, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Dr. Enéas Carvalho Aguiar 255, 05403-900 São Paulo SP, Brazil.
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Al-Muhaizea MA, AlQuait L, AlRasheed A, AlHarbi S, Albader AA, AlMass R, Albakheet A, Alhumaidan A, AlRasheed MM, Colak D, Kaya N. Pyrostigmine therapy in a patient with VAMP1-related congenital myasthenic syndrome. Neuromuscul Disord 2020; 30:611-615. [DOI: 10.1016/j.nmd.2020.04.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 03/25/2020] [Accepted: 04/27/2020] [Indexed: 12/19/2022]
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