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Palmio J, Kiviranta P, Hartikainen PH, Isohanni P, Auranen M, Videman K, Penttilä S, Lehtinen S, Kirjavainen J, Hintikka S, Paloviita K, Saarela J, Udd B. Homozygosity of a Founder Variant c.1508dupC in DOK7 Causes Congenital Myasthenia With Variable Severity. Neurol Genet 2024; 10:e200155. [PMID: 38725677 PMCID: PMC11081763 DOI: 10.1212/nxg.0000000000200155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Accepted: 03/14/2024] [Indexed: 05/12/2024]
Abstract
Background and Objectives Description of 15 patients with the same variant in DOK7 causing congenital myasthenic syndrome (CMS). Methods Nine adult and 6 pediatric patients were studied with molecular genetic and clinical investigations. Results All patients were identified with the c.1508dupC variant in DOK7, of whom 13 were homozygous and 2 patients compound heterozygous. Only 2 patients had limb girdle phenotype, while all adult patients also had ptosis, ophthalmoplegia, facial weakness, as well as inspiratory stridor. Pediatric patients had severe respiratory insufficiency and feeding difficulties at birth. Discussion The disease severity in our patients varied extensively from ventilator or wheelchair dependence to mild facial weakness, ptosis, and ophthalmoparesis. Most of the patients had normal transmission in conventional 3 Hz stimulation electrophysiologic studies, making the diagnosis of CMS challenging. Our cohort of adult and pediatric patients expands the phenotype of DOK7 CMS and shows the importance of correct and early diagnosis.
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Affiliation(s)
- Johanna Palmio
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Panu Kiviranta
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Päivi H Hartikainen
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Pirjo Isohanni
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Mari Auranen
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Karoliina Videman
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Sini Penttilä
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Sara Lehtinen
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Jarkko Kirjavainen
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Susanna Hintikka
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Katriina Paloviita
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Janna Saarela
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
| | - Bjarne Udd
- From the Neuromuscular Research Center (J.P., S.P., B.U.), Tampere University and University Hospital, Neurology; The Finnish Medical Society Duodecim (P.K.), Helsinki; Department of Pediatrics (P.K.), Kuopio University Hospital, and University of Eastern Finland Kuopio; Neurocenter (P.H.H.), Neurology, Kuopio University Hospital; Department of Child Neurology (P.I.), Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital; Research Programs Unit (P.I.), Stem Cells and Metabolism, University of Helsinki; Clinical Neurosciences (M.A.), Neurology, University of Helsinki and Helsinki University Hospital; Department of Pediatric Neurology (K.V.); Department of Genetics (S.L.), Fimlab Laboratories, Tampere University Hospital; Department of Pediatric Neurology (J.K.), Kuopio University Hospital; Department of Neurology (S.H., K.P.), Central Finland Central Hospital, Jyväskylä; Institute for Molecular Medicine Finland FIMM (J.S.), University Helsinki, Finland; Centre for Molecular Medicine Norway (J.S.), University of Oslo, Norway; Folkhälsan Institute of Genetics and the Department of Medical Genetics (B.U.), Haartman Institute, University of Helsinki; and Department of Neurology (B.U.), Vaasa Central Hospital, Finland
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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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Polavarapu K, Sunitha B, Töpf A, Preethish-Kumar V, Thompson R, Vengalil S, Nashi S, Bardhan M, Sanka SB, Huddar A, Unnikrishnan G, Arunachal G, Girija MS, Porter A, Azuma Y, Lorenzoni PJ, Baskar D, Anjanappa RM, Keertipriya M, Padmanabh H, Harikrishna GV, Laurie S, Matalonga L, Horvath R, Nalini A, Lochmüller H. Clinical and genetic characterisation of a large Indian congenital myasthenic syndrome cohort. Brain 2024; 147:281-296. [PMID: 37721175 PMCID: PMC10766255 DOI: 10.1093/brain/awad315] [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: 03/13/2023] [Revised: 06/20/2023] [Accepted: 08/10/2023] [Indexed: 09/19/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are a rare group of inherited disorders caused by gene defects associated with the neuromuscular junction and potentially treatable with commonly available medications such as acetylcholinesterase inhibitors and β2 adrenergic receptor agonists. In this study, we identified and genetically characterized the largest cohort of CMS patients from India to date. Genetic testing of clinically suspected patients evaluated in a South Indian hospital during the period 2014-19 was carried out by standard diagnostic gene panel testing or using a two-step method that included hotspot screening followed by whole-exome sequencing. In total, 156 genetically diagnosed patients (141 families) were characterized and the mutational spectrum and genotype-phenotype correlation described. Overall, 87 males and 69 females were evaluated, with the age of onset ranging from congenital to fourth decade (mean 6.6 ± 9.8 years). The mean age at diagnosis was 19 ± 12.8 (1-56 years), with a mean diagnostic delay of 12.5 ± 9.9 (0-49 years). Disease-causing variants in 17 CMS-associated genes were identified in 132 families (93.6%), while in nine families (6.4%), variants in genes not associated with CMS were found. Overall, postsynaptic defects were most common (62.4%), followed by glycosylation defects (21.3%), synaptic basal lamina genes (4.3%) and presynaptic defects (2.8%). Other genes found to cause neuromuscular junction defects (DES, TEFM) in our cohort accounted for 2.8%. Among the individual CMS genes, the most commonly affected gene was CHRNE (39.4%), followed by DOK7 (14.4%), DPAGT1 (9.8%), GFPT1 (7.6%), MUSK (6.1%), GMPPB (5.3%) and COLQ (4.5%). We identified 22 recurrent variants in this study, out of which eight were found to be geographically specific to the Indian subcontinent. Apart from the known common CHRNE variants p.E443Kfs*64 (11.4%) and DOK7 p.A378Sfs*30 (9.3%), we identified seven novel recurrent variants specific to this cohort, including DPAGT1 p.T380I and DES c.1023+5G>A, for which founder haplotypes are suspected. This study highlights the geographic differences in the frequencies of various causative CMS genes and underlines the increasing significance of glycosylation genes (DPAGT1, GFPT1 and GMPPB) as a cause of neuromuscular junction defects. Myopathy and muscular dystrophy genes such as GMPPB and DES, presenting as gradually progressive limb girdle CMS, expand the phenotypic spectrum. The novel genes MACF1 and TEFM identified in this cohort add to the expanding list of genes with new mechanisms causing neuromuscular junction defects.
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Affiliation(s)
- Kiran Polavarapu
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
| | - Balaraju Sunitha
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
- Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge CB2 0SP, UK
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - Ana Töpf
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Veeramani Preethish-Kumar
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
- Department of Neurology, Neurofoundation, Salem, Tamil Nadu 636009, India
| | - Rachel Thompson
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
| | - Seena Vengalil
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Saraswati Nashi
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Mainak Bardhan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Sai Bhargava Sanka
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Akshata Huddar
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
- Department of Neurology, St Johns Medical College Hospital, Bangalore 560034, India
| | - Gopikrishnan Unnikrishnan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
- Department of Neurology, Amruta Institute of Medical Sciences, Kochi 682041, India
| | - Gautham Arunachal
- Department of Human Genetics, National Institute of Mental Health and Neurosciences, Bengaluru 560029, India
| | - Manu Santhappan Girija
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Anna Porter
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Yoshiteru Azuma
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne NE1 3BZ, UK
| | - Paulo José Lorenzoni
- Neuromuscular Disorders Division, Service of Neurology, Department of Internal Medicine, Hospital de Clínicas, Universidade Federal do Paraná, Rua General Carneiro, Curitiba - PR 80060-900, Brazil
| | - Dipti Baskar
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Ram Murthy Anjanappa
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Madassu Keertipriya
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Hansashree Padmanabh
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | | | - Steve Laurie
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia 08028, Spain
| | - Leslie Matalonga
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia 08028, Spain
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge School of Clinical Medicine, Cambridge CB2 0SP, UK
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore 560029, India
| | - Hanns Lochmüller
- Children’s Hospital of Eastern Ontario Research Institute, Ottawa, ON K1H 8L1, Canada
- Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia 08028, Spain
- Brain and Mind Research Institute, University of Ottawa, Ottawa, ON K1H 8M5, Canada
- Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, ON K1H 8M5, Canada
- Department of Neuropediatrics and Muscle Disorders, Medical Center–University of Freiburg, Faculty of Medicine, Freiburg 79110, Germany
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Pascoe JE, Zygmunt A, Ehsan Z, Gurbani N. Sleep in pediatric neuromuscular disorders. Semin Pediatr Neurol 2023; 48:101092. [PMID: 38065635 DOI: 10.1016/j.spen.2023.101092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 10/06/2023] [Accepted: 10/09/2023] [Indexed: 12/18/2023]
Abstract
Sleep disordered breathing (SDB) is prevalent among children with neuromuscular disorders (NMD). The combination of respiratory muscle weakness, altered drive, and chest wall distortion due to scoliosis make sleep a stressful state in this population. Symptomatology can range from absent to snoring, nocturnal awakenings, morning headaches, and excessive daytime sleepiness. Sequelae of untreated SDB includes cardiovascular effects, metabolic derangements, and neurocognitive concerns which can be compounded by those innate to the NMD. The clinician should have a low threshold for obtaining polysomnography and recognize the nuances of individual disorders due to disproportionately impacted muscle groups such as hypoventilation in ambulating patients from diaphragm weakness. Non-invasive or invasive ventilation are the mainstay of treatment. In this review we explore the diagnosis and treatment of SDB in children with various NMD.
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Affiliation(s)
- John E Pascoe
- Division of Pulmonary and Sleep Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States.
| | - Alexander Zygmunt
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States; Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Zarmina Ehsan
- Division of Pulmonary and Sleep Medicine, Children's Mercy-Kansas City, Kansas City, MO, United States; Department of Pediatrics, University of Missouri-Kansas City School of Medicine, Kansas City, MO, United States
| | - Neepa Gurbani
- Division of Pulmonary and Sleep Medicine, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
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5
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Özsoy Ö, Cinleti T, Günay Ç, Sarıkaya Uzan G, Giray Bozkaya Ö, Çağlayan AO, Hız Kurul S, Yiş U. Genetic, serological and clinical evaluation of childhood myasthenia syndromes- single center subgroup analysis experience in Turkey. Acta Neurol Belg 2023; 123:2325-2335. [PMID: 37656362 DOI: 10.1007/s13760-023-02370-3] [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: 04/04/2023] [Accepted: 08/21/2023] [Indexed: 09/02/2023]
Abstract
BACKGROUND Congenital myasthenic syndrome is a disease that occurs due to several types such as mutations in different pre-synaptic, synaptic, post-synaptic proteins and, glycosylation defects associated with congenital myopathy. Juvenile myasthenia gravis is an autoimmune condition usually caused by antibodies targeting the acetylcholine receptor. AIMS Our objective is to conduct an analysis on the subgroup traits exhibited by patients who have been diagnosed with congenital myasthenic syndrome and juvenile myasthenia gravis, with a focus on their long-term monitoring and management. METHODS This study was conducted on children diagnosed with myasthenia gravis, who were under the care of Dokuz Eylul University's Department of Pediatric Neurology for a period of ten years. RESULTS A total of 22 (12 congenital myasthenic syndrome, 10 juvenile myasthenia gravis) patients were identified. Defects in the acetylcholine receptor (6/12) were the most common type in the congenital myasthenic syndrome group. Basal-lamina-related defects (5/12) were the second most prevalent. One patient had a GFPT1 gene mutation (1/12). Patients with ocular myasthenia gravis (n = 6) exhibited milder symptoms. In the generalized myasthenia gravis group (n = 4), specifically in postpubertal girls, a more severe clinical progression was observed, leading to the implementation of more aggressive treatment strategies. CONCLUSION This study highlights that clinical recognition of congenital myasthenic syndrome and knowledge of related genes will aid the rapid diagnosis and treatment of these rare neuromuscular disorders. Findings in the juvenile myasthenia gravis group demonstrate the impact of pubertal development and the need for timely and appropriate active therapy, including thymectomy, to improve prognosis.
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Affiliation(s)
- Özlem Özsoy
- Department of Pediatric Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey.
| | - Tayfun Cinleti
- Department of Pediatric Genetics, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Çağatay Günay
- Department of Pediatric Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Gamze Sarıkaya Uzan
- Department of Pediatric Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Özlem Giray Bozkaya
- Department of Pediatric Genetics, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
| | - Ahmet Okay Çağlayan
- Department of Medical Genetics, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
- Department of Molecular Medicine, Institute of Health Sciences, Dokuz Eylül University, İzmir, Turkey
| | - Semra Hız Kurul
- Department of Pediatric Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
- İzmir Biomedicine and Genome Center, Dokuz Eylül University Health Campus, İzmir, Turkey
- İzmir International Biomedicine and Genome Institute, Dokuz Eylül University, İzmir, Turkey
| | - Uluç Yiş
- Department of Pediatric Neurology, Faculty of Medicine, Dokuz Eylül University, İzmir, Turkey
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Mishra S, Nair KV, Shukla A. Delineation of molecular characteristics of congenital myasthenic syndromes in Indian families and review of literature. Clin Dysmorphol 2023; 32:162-167. [PMID: 37646703 DOI: 10.1097/mcd.0000000000000465] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
Abstract
Congenital myasthenic syndromes (CMS) are rare, heterogeneous, and often treatable genetic disorders depending on the underlying molecular defect. We performed a detailed clinical evaluation of seven patients from five unrelated families. Exome sequencing was performed on five index patients. Clinically significant variants were identified in four CMS disease-causing genes: COLQ (3/7), CHRNE (2/7), DOK7 (1/7), and RAPSN (1/7). We identified two novel variants, c.930_933delCATG in DOK7 and c.1016_1032 + 2dup in CHRNE . A common pathogenic variant, c.955-2A>C, has been identified in COLQ -related CMS patients. Homozygosity mapping of this COLQ variant in patients from two unrelated families revealed that it was located in a common homozygous region of 3.2 Mb on chromosome 3 and was likely to be inherited from a common ancestor. Patients with COLQ variants had generalized muscle weakness, those with DOK7 and RAPSN variants had limb-girdle weakness, and those with CHRNE variants had predominant ocular weakness. Patients with COLQ and DOK7 variants showed improvement with salbutamol and CHRNE with pyridostigmine therapy. This study expands the mutational spectrum and adds a small but significant cohort of CMS patients from India. We also reviewed the literature to identify genetic subtypes of CMS in India.
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Affiliation(s)
- Shivani Mishra
- Department of Medical Genetics, Kasturba Medical College, Manipal, Manipal Academy of Higher Education, Manipal, Karnataka, India
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Yildiz EP, Kilic MA, Yalcin EU, Kurekci F, Avci R, Hacıfazlıoğlu NE, Ceylaner S, Gezdirici A, Çalışkan M. Genetic and clinical evaluation of congenital myasthenic syndromes with long-term follow-up: experience of a tertiary center in Turkey. Acta Neurol Belg 2023; 123:1841-1847. [PMID: 36094697 DOI: 10.1007/s13760-022-02090-0] [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: 05/09/2022] [Accepted: 09/01/2022] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Congenital myasthenic syndromes (CMS) are a heterogeneous group of genetic disorders affecting the safety factor which required for neuromuscular transmission. Here we reported our experience in children with CMS. METHODS We retrospectively collected the data of 18 patients with CMS who were examined in our outpatient clinic between January 2021 and January 2022. The diagnosis of CMS was based on the presence of clinical symptoms such as abnormal fatigability and weakness, absence of autoantibodies against acetylcholine receptor and muscle-specific kinase, electromyographic evidence of neuromuscular junction defect, molecular genetic confirmation, and response to treatment. RESULTS The most common mutations were in the acetylcholine receptor (CHRNE) gene (8/18) and choline acetyltransferase (ChAT) (2/18) gene. Despite targeted gene sequencing and whole exome sequencing (WES) were underwent, we couldn't detect a genetic mutation in three out of patients. The most commonly determined initial finding was eyelid ptosis, followed by fatigable weakness, and respiratory insufficiency. Although the most commonly used drug was pyridostigmine, we have experienced that caution should be exercised as it may worsen some types of CMS. DISCUSSION We reported in detail the phenotypic features of very rare gene mutations associated with CMS and our experience in the treatment of this disease. Although CMS are rare genetic disorder, the prognosis can be very promising with appropriate treatment in most CMS subtypes.
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Affiliation(s)
- Edibe Pembegul Yildiz
- Department of Pediatric Neurology, Istanbul Medical Faculty, Istanbul, Turkey.
- Istanbul University Institute of Child Health, Istanbul, Turkey.
- Istanbul University Medical School. Millet Cd, 34000, Fatih-Istanbul, Turkey.
| | - Mehmet Akif Kilic
- Department of Pediatric Neurology, Istanbul Medical Faculty, Istanbul, Turkey
| | - Emek Uyur Yalcin
- Department of Pediatric Neurology, Zeynep Kamil Maternity and Children's Diseases Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | - Fulya Kurekci
- Department of Pediatric Neurology, Istanbul Medical Faculty, Istanbul, Turkey
| | - Ridvan Avci
- Department of Pediatric Neurology, Istanbul Medical Faculty, Istanbul, Turkey
| | - Nilüfer Eldeş Hacıfazlıoğlu
- Department of Pediatric Neurology, Zeynep Kamil Maternity and Children's Diseases Training and Research Hospital, University of Health Sciences, Istanbul, Turkey
| | | | - Alper Gezdirici
- Department of Medical Genetics, Basaksehir Cam and Sakura City Hospital, Istanbul, Turkey
| | - Mine Çalışkan
- Department of Pediatric Neurology, Istanbul Medical Faculty, Istanbul, Turkey
- Istanbul University Institute of Child Health, Istanbul, Turkey
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8
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Spendiff S, Dong Y, Maggi L, Rodríguez Cruz PM, Beeson D, Lochmüller H. 260th ENMC International Workshop: Congenital myasthenic syndromes 11-13 March 2022, Hoofddorp, The Netherlands. Neuromuscul Disord 2023; 33:111-118. [PMID: 36609117 DOI: 10.1016/j.nmd.2022.12.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/02/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022]
Affiliation(s)
- Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada
| | - Yin Dong
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Lorenzo Maggi
- Neuroimmunology and Neuromuscular Diseases Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Pedro M Rodríguez Cruz
- Centro Nacional de Análisis Genómico (CNAG-CRG), Centre for Genomic Regulation, Barcelona, Spain; Department of Human Genetics, Université Cheikh Anta Diop, Dakar, Senegal; Department of Neuromuscular Diseases, UCL Institute of Neurology, London, UK
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Hanns Lochmüller
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, Canada; Department of Medicine, Division of Neurology, The Ottawa Hospital, Ottawa, Canada; Brain and Mind Research Institute, University of Ottawa, Ottawa, Canada; Department of Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Faculty of Medicine, Freiburg, Germany; Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Catalonia, Spain.
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9
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Eshaghian T, Rabbani B, Badv RS, Mikaeeli S, Gharib B, Iyadurai S, Mahdieh N. COLQ-related congenital myasthenic syndrome: An integrative view. Neurogenetics 2023; 24:189-200. [PMID: 37231228 DOI: 10.1007/s10048-023-00719-7] [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: 03/14/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023]
Abstract
Congenital myasthenic syndromes are inherited disorders caused by mutation in components of the neuromuscular junction and manifest early in life. Mutations in COLQ gene result in congenital myasthenic syndrome. Here, we present the analysis of data from 209 patients from 195 unrelated families highlighting genotype-phenotype correlation. In addition, we describe a COLQ homozygous variant a new patient and discuss it utilizing the Phyre2 and I-TASSER programs. Clinical, molecular genetics, imaging (MRI), and electrodiagnostic (EEG, EMG/NCS) evaluations were performed. Our data showed 89 pathogenic/likely pathogenic variants including 35 missenses, 21 indels, 14 nonsense, 14 splicing, and 5 large deletions variants. Eight common variants were responsible for 48.46% of those. Weakness in proximal muscles, hypotonia, and generalized weakness were detected in all individuals tested. Apart from the weakness, extensive clinical heterogeneity was noted among patients with COLQ-related patients based on their genotypes-those with variants affecting the splice site exhibited more severe clinical features while those with missense variants displayed milder phenotypes, suggesting the role of differential splice variants in multiple functions within the muscle. Analyses and descriptions of these COLQ variants may be helpful in clinical trial readiness and potential development of novel therapies in the setting of established structure-function relationships.
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Affiliation(s)
- Tina Eshaghian
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Bahareh Rabbani
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Reza Shervin Badv
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Sahar Mikaeeli
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran
| | - Behdad Gharib
- Children's Hospital Center, Pediatric Center of Excellence, Tehran University of Medical Center, Tehran, Iran
| | - Stanley Iyadurai
- Johns Hopkins All Children's Hospital, Division of Neurology, 601 5th Street S, St. Petersburg, FL, 33701, USA
| | - Nejat Mahdieh
- Growth and Development Research, Tehran University of Medical Sciences, Tehran, Iran.
- Cardiogenetic Research Center, Rajaie Cardiovascular Medical and Research Center, Iran University of Medical Sciences, Niayesh-Vali asr Intersection, Tehran, Iran.
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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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11
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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: 34] [Impact Index Per Article: 34.0] [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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12
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Zhang Q, Sha Q, Qiao K, Liu X, Gong X, Du A. Two patients with congenital myasthenic syndrome caused by COLQ gene mutations and the consequent ColQ protein defect. Heliyon 2023; 9:e13272. [PMID: 36798769 PMCID: PMC9925971 DOI: 10.1016/j.heliyon.2023.e13272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 12/12/2022] [Accepted: 01/24/2023] [Indexed: 01/27/2023] Open
Abstract
Objective To report two cases of congenital myasthenic syndromes (CMS) in a Chinese family with mutations in the COLQ gene and to prove the consequence defect of the ColQ protein. Method Clinical characteristics of the two children from the same family were described. Next-generation sequencing (NGS) and sanger sequencing was performed on the proband and family members. The consequence of the mutation was predicted by 3D protein structure prediction using I-TASSER. The wild type and mutant were transfected to 293T cells, and ColQ protein was detected by Western Blot. Results The diagnosis of CMS was based on a symptom combination of fatigable muscle weakness, ptosis, scoliosis, and hypotonia, aggravation of muscle weakness after the neostigmine test, and a 46% decrement in repetitive nerve stimulation. A muscle biopsy was performed on the proband, revealing mild variation in the myofiber size. NGS data revealed two compound heterozygous mutations at c.173delC (p.Pro58Hisfs*22) and c.C706T (p.R236X) in the COLQ gene, where the former was a novel mutation. A 3D structure prediction showed two truncated ColQ proteins with 78aa and 235aa, respectively. The truncated ColQ protein was proved in 293T cells transfected with c.173delC or c.C706T mutants by Western Blot. Conclusions The mutations of c.173delC and c.C706T in the COLQ gene led to truncated ColQ protein and contributed to the pathogenesis of CMS in this Chinese family.
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Affiliation(s)
- Qiting Zhang
- Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200336, China
| | - Qianqian Sha
- Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200336, China
| | - Kai Qiao
- Department of Neurology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Xiaoli Liu
- Department of Neurology, Shanghai Fengxian District Central Hospital, Shanghai Jiao Tong University Affiliated Sixth People's Hospital South Campus, Shanghai, 201406, China
| | - Xiaohui Gong
- Department of Neonatology, Shanghai Children's Hospital, Shanghai, 200062, China
- Corresponding author.
| | - Ailian Du
- Department of Neurology, Tongren Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, 200336, China
- Corresponding author.
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13
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Kramer JJ, Boon HTM, Leijten QH, Ter Laak H, Eshuis L, Kusters B, van Doorn JLM, Kamsteeg EJ, Eymard B, Doorduin J, Voermans NC. Dystrophic Myopathy of the Diaphragm with Recurrent Severe Respiratory Failure is Congenital Myasthenic Syndrome 11. J Neuromuscul Dis 2023; 10:271-277. [PMID: 36591657 PMCID: PMC10041432 DOI: 10.3233/jnd-221542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We here present the case of a patient with a congenital myasthenic syndrome (CMS) due to pathogenic variants in the RAPSN gene. During childhood he experienced recurrent episodes of respiratory failure during respiratory infections. This and other cases were reported as isolated dystrophy of the diaphragmatic musculature. In adulthood, whole exome sequencing revealed two heterozygous pathogenic variants in the RAPSN gene. This led to the revision of the diagnosis to rapsyn CMS11 (OMIM:616326, MONDO:0014588). EMG, muscle ultrasound and the revision of muscle biopsies taken in childhood support this diagnosis. After the revision of the diagnosis, treatment with pyridostigmine was started. This resulted in a reduction of fatigability and an improvement in functional abilities and quality of life.
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Affiliation(s)
- J J Kramer
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - H T M Boon
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | | | - Henk Ter Laak
- Department of Pathology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - L Eshuis
- Department of Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - B Kusters
- Department of Pathology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - J L M van Doorn
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - E J Kamsteeg
- Department of Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - B Eymard
- Institute de Myologie, Paris, France
| | - J Doorduin
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - N C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
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14
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Huang K, Duan HQ, Li QX, Luo YB, Bi FF, Yang H. Clinicopathological-genetic features of congenital myasthenic syndrome from a Chinese neuromuscular centre. J Cell Mol Med 2022; 26:3828-3836. [PMID: 35670010 PMCID: PMC9279597 DOI: 10.1111/jcmm.17417] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 05/13/2022] [Accepted: 05/20/2022] [Indexed: 12/28/2022] Open
Abstract
Congenital myasthenic syndrome (CMS) encompasses a heterogeneous group of inherited disorders affecting nerve transmission across the neuromuscular junction. The aim of this study was to characterize the clinical, physiological, pathohistological and genetic features of nine unrelated Chinese patients with CMS from a single neuromuscular centre. A total of nine patients aged from neonates to 34 years were enrolled who exhibited initial symptoms. Physical examinations revealed that all patients exhibited muscle weakness. Muscle biopsies demonstrated multiple myopathological changes, including increased fibre size variation, myofibrillar network disarray, necrosis, myofiber grouping, regeneration, fibre atrophy and angular fibres. Genetic testing revealed six different mutated genes, including AGRN (2/9), CHRNE (1/9), GFPT1 (1/9), GMPPB (1/9), PLEC (3/9) and SCN4A (1/9). In addition, patients exhibited differential responses to pharmacological treatment. Prompt utilization of genetic testing will identify novel variants and expand our understanding of the phenotype of this rare syndrome. Our findings contribute to the clinical, pathohistological and genetic spectrum of congenital myasthenic syndrome in China.
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Affiliation(s)
- Kun Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China.,Institute of Molecular Precision Medicine and Hunan Key Laboratory of Molecular Precision Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Hui-Qian Duan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Qiu-Xiang Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Yue-Bei Luo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Fang-Fang Bi
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
| | - Huan Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, China
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15
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Gómez-García de la Banda M, Simental-Aldaba E, Fahmy N, Sternberg D, Blondy P, Quijano-Roy S, Malfatti E. Case Report: A Novel AChR Epsilon Variant Causing a Clinically Discordant Salbutamol Responsive Congenital Myasthenic Syndrome in Two Egyptian Siblings. Front Neurol 2022; 13:909715. [PMID: 35720108 PMCID: PMC9201482 DOI: 10.3389/fneur.2022.909715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/02/2022] [Indexed: 12/05/2022] Open
Abstract
Congenital myasthenic syndromes (CMS) are inherited disorders that lead to abnormal neuromuscular transmission. Post-synaptic mutations are the main cause of CMS, particularly mutations in CHRNE. We report a novel homozygous CHRNE pathogenic variant in two Egyptian siblings showing a CMS. Interestingly, they showed different degrees of extraocular and skeletal muscle involvement; both presented only a partial response to cholinesterase inhibitors, and rapidly and substantially ameliorated after the addition of oral β2 adrenergic agonists. Here, we enlarge the genetic spectrum of CHRNE-related congenital myasthenic syndromes and highlight the importance of a β2 adrenergic agonists treatment.
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Affiliation(s)
- Marta Gómez-García de la Banda
- Pediatric Neurology and ICU Department, AP-HP Université Paris Saclay, Hôpital Raymond Poincaré, Garches, France
- Reference Center for Neuromuscular Diseases Centre “Nord- Est- Ile de France”, FILNEMUS, Creteil, France
- European Reference Center Network (Euro-NMD ERN), Paris, France
| | - Emmanuel Simental-Aldaba
- APHP, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor University Hospital, Créteil, France
- Department of Neurorehabilitation, Instituto Nacional de Rehabilitación “LGII”, Mexico City, Mexico
| | - Nagia Fahmy
- Neuromuscular Unit, Faculty of Medicine, Ain Shams University, Cairo, Egypt
| | - Damien Sternberg
- European Reference Center Network (Euro-NMD ERN), Paris, France
- Service de Biochimie Métabolique, Centre de Génétique, Groupe Hospitalier Pitié-Salpêtrière, APHP Sorbonne Université, Paris, France
| | - Patricia Blondy
- European Reference Center Network (Euro-NMD ERN), Paris, France
| | - Susana Quijano-Roy
- Pediatric Neurology and ICU Department, AP-HP Université Paris Saclay, Hôpital Raymond Poincaré, Garches, France
- Reference Center for Neuromuscular Diseases Centre “Nord- Est- Ile de France”, FILNEMUS, Creteil, France
- European Reference Center Network (Euro-NMD ERN), Paris, France
- Centre de Recherche en Myologie, UMRS974, Paris, France
| | - Edoardo Malfatti
- Reference Center for Neuromuscular Diseases Centre “Nord- Est- Ile de France”, FILNEMUS, Creteil, France
- APHP, Centre de Référence de Pathologie Neuromusculaire Nord-Est-Ile-de-France, Henri Mondor University Hospital, Créteil, France
- Univ Paris Est Créteil, INSERM, IMRB, Créteil, France
- AP-HP, Hôpital Mondor, Service d'histologie, Créteil, France
- *Correspondence: Edoardo Malfatti
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16
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Boon HTM, Jacobs B, Wouter VR, Kamsteeg EJ, Kuks JBM, Vincent A, Eymard B, Voermans NC. Slow Channel Syndrome Revisited: 40 Years Clinical Follow-Up and Genetic Characterization of Two Cases. J Neuromuscul Dis 2022; 9:525-532. [PMID: 35466948 DOI: 10.3233/jnd-220798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND The slow channel syndrome is a rare hereditary disorder caused by a dominant gain-of-function variant in one of the subunits of the acetylcholine receptor at the neuromuscular junction. Patients typically experience axial, limb and particularly extensor finger muscle weakness. OBJECTIVE Age at diagnosis is variable and although the long-term prognosis is important for newly diagnosed patients, extensive follow-up studies are rare. We aim to provide answers and perspective for this patient group by presenting an elaborate description of the lifetime follow-up of two slow channel syndrome patients. METHODS We describe 40 years follow-up in two, genetically confirmed cases (CHRNA1; c.866G > T p.(Ser289Ile)(legacy Ser269Ile) and CHRNE; c.721C > T p.(Leu241Phe)(legacy Leu221Phe) variants). RESULTS We find that the disease course has a fluctuating pattern and is only mildly progressive. However, hormonal imbalances, (psychological) stress or excessive hot or cold environments are often aggravating factors. Quinidine and fluoxetine are helpful, but ephedrine and salbutamol may also improve symptoms. CONCLUSION Slow channel syndrome is mildly progressive with a fluctuating pattern. The observations reported here provide a lifespan perspective and answers to the most pressing questions about prognosis and treatment options for newly diagnosed patients.
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Affiliation(s)
- Helena T M Boon
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Bram Jacobs
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - van Rheenen Wouter
- Department of Neurology, University Medical Centre Utrecht, The Netherlands
| | - Erik-Jan Kamsteeg
- Department of Genetics, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Jan B M Kuks
- Department of Neurology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, UK
| | | | - Nicol C Voermans
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
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17
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Park JH, Cho YW, Kim TH. Recent Advances in Surface Plasmon Resonance Sensors for Sensitive Optical Detection of Pathogens. BIOSENSORS 2022; 12:180. [PMID: 35323450 PMCID: PMC8946561 DOI: 10.3390/bios12030180] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 03/09/2022] [Accepted: 03/11/2022] [Indexed: 05/06/2023]
Abstract
The advancement of science and technology has led to the recent development of highly sensitive pathogen biosensing techniques. The effective treatment of pathogen infections requires sensing technologies to not only be sensitive but also render results in real-time. This review thus summarises the recent advances in optical surface plasmon resonance (SPR) sensor technology, which possesses the aforementioned advantages. Specifically, this technology allows for the detection of specific pathogens by applying nano-sized materials. This review focuses on various nanomaterials that are used to ensure the performance and high selectivity of SPR sensors. This review will undoubtedly accelerate the development of optical biosensing technology, thus allowing for real-time diagnosis and the timely delivery of appropriate treatments as well as preventing the spread of highly contagious pathogens.
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Affiliation(s)
| | | | - Tae-Hyung Kim
- School of Integrative Engineering, Chung-Ang University, 84 Heukseuk-ro, Dongjak-gu, Seoul 06974, Korea; (J.-H.P.); (Y.-W.C.)
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18
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Saito M, Ogasawara M, Inaba Y, Osawa Y, Nishioka M, Yamauchi S, Atsumi K, Takeuchi S, Imai K, Motobayashi M, Misawa Y, Iida A, Nishino I. Successful treatment of congenital myasthenic syndrome caused by a novel compound heterozygous variant in RAPSN. Brain Dev 2022; 44:50-55. [PMID: 34565654 DOI: 10.1016/j.braindev.2021.09.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/29/2021] [Accepted: 09/05/2021] [Indexed: 11/27/2022]
Abstract
BACKGROUND Congenital myasthenic syndrome (CMS) is a clinically and genetically heterogeneous neuromuscular disorder characterized by muscle weakness and caused by mutations in more than 35 different genes. This condition should not be overlooked as a subset of patients with CMS are treatable. However, the diagnosis of CMS is often difficult due to the broad variability in disease severity and course. CASE REPORT A five-year-old boy without remarkable family history was born with marked general muscle hypotonia and weakness, respiratory insufficiency, anomalies, and multiple joint contractures. Congenital myopathy was suspected based upon type 1 fiber predominance on muscle biopsy. However, he was diagnosed with CMS at age 4 years when his ptosis and ophthalmoplegia were found to be improved by edrophonium chloride and repetitive nerve stimulation showed attenuation of compound muscle action potentials. An exome sequencing identified a compound heterozygous missense variant of c.737C > T (p.A246V) and a novel intronic insertion c.1166 + 4_1166 + 5insAAGCCCACCAC in RAPSN. RT-PCR analysis which showed the skipping of exon 7 in a skeletal muscle sample confirmed that the intronic insertion was pathogenic. His myasthenic symptoms were remarkably improved by pyridostigmine. CONCLUSION The patient's diagnosis of CMS was confirmed by exome sequencing, and RT-PCR revealed that the skipping of exon 7 in RAPSN was caused by a novel intronic insertion. The genetic information uncovered in this case should therefore be added to the collection of tools for diagnosing and treating CMS.
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Affiliation(s)
- Maki Saito
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan
| | - Masashi Ogasawara
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan; Medical Genome Center, NCNP, Kodaira, Tokyo, Japan
| | - Yuji Inaba
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan; Life Science Research Center, Nagano Children's Hospital, Azumino, Japan.
| | - Yoshihiro Osawa
- Department of Pediatrics, Iida Municipal Hospital, Iida, Japan
| | - Makoto Nishioka
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan; Life Science Research Center, Nagano Children's Hospital, Azumino, Japan
| | - Shoko Yamauchi
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan
| | - Kana Atsumi
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan
| | - Shihoko Takeuchi
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan
| | - Ken Imai
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan
| | - Mitsuo Motobayashi
- Division of Neuropediatrics, Nagano Children's Hospital, Azumino, Japan; Life Science Research Center, Nagano Children's Hospital, Azumino, Japan
| | - Yuka Misawa
- Division of Rehabilitation, Nagano Children's Hospital, Azumino, Japan
| | | | - Ichizo Nishino
- Department of Neuromuscular Research, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Kodaira, Tokyo, Japan; Medical Genome Center, NCNP, Kodaira, Tokyo, Japan
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19
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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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20
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Rare slow channel congenital myasthenic syndromes without repetitive compound muscle action potential and dramatic response to low dose fluoxetine. Acta Neurol Belg 2021; 121:1755-1760. [PMID: 33030681 DOI: 10.1007/s13760-020-01505-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 09/15/2020] [Indexed: 10/23/2022]
Abstract
Congenital myasthenic syndromes are rare hereditary disorders caused by mutations associated with proteins of the neuromuscular junction. Abnormal ''gain of function'' mutations result in prolonged nicotinic acetylcholine receptor channel open state causing a rare subtype of CMS, slow-channel CMS (SCCMS). Mutations in the delta subunit encoding the gene, CHRND, resulting in SCCMS are extremely rare. An important clue to the diagnosis of SCCMS is repetitive CMAP's. Fluoxetine, usually at high doses, is used to treat SCCMS. The mutation, recently described in one patient, was identified by whole exome sequencing and validated, and its segregation with the disease was ascertained by Sanger sequencing. Here, we describe clinical and genetic findings of an early onset SCCMS patient carrying a very rare missense mutation c.880C > T in CHRND causing a highly conserved leucine to phenylalanine substitution in the M2 domain of CHRND. The patient had no repetitive CMAP. He had a dramatic response to fluoxetine at low-moderate doses (40 mg/day), increasing over months: Being wheelchair bound, he could walk independently after treatment. Rare cases may offer insight into the pathological gating mechanism leading to CMS. SCCMS should be suspected even without a repetitive CMAP. Fluoxetine at relatively low doses can be a very effective treatment.
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21
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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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22
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Maggi L, Bonanno S, Altamura C, Desaphy JF. Ion Channel Gene Mutations Causing Skeletal Muscle Disorders: Pathomechanisms and Opportunities for Therapy. Cells 2021; 10:cells10061521. [PMID: 34208776 PMCID: PMC8234207 DOI: 10.3390/cells10061521] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 06/03/2021] [Accepted: 06/10/2021] [Indexed: 02/06/2023] Open
Abstract
Skeletal muscle ion channelopathies (SMICs) are a large heterogeneous group of rare genetic disorders caused by mutations in genes encoding ion channel subunits in the skeletal muscle mainly characterized by myotonia or periodic paralysis, potentially resulting in long-term disabilities. However, with the development of new molecular technologies, new genes and new phenotypes, including progressive myopathies, have been recently discovered, markedly increasing the complexity in the field. In this regard, new advances in SMICs show a less conventional role of ion channels in muscle cell division, proliferation, differentiation, and survival. Hence, SMICs represent an expanding and exciting field. Here, we review current knowledge of SMICs, with a description of their clinical phenotypes, cellular and molecular pathomechanisms, and available treatments.
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Affiliation(s)
- Lorenzo Maggi
- Neuroimmunology and Neuromuscular Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy;
- Correspondence:
| | - Silvia Bonanno
- Neuroimmunology and Neuromuscular Disorders Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, 20133 Milan, Italy;
| | - Concetta Altamura
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.A.); (J.-F.D.)
| | - Jean-François Desaphy
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari Aldo Moro, 70124 Bari, Italy; (C.A.); (J.-F.D.)
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23
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Gül Mert G, Özcan N, Hergüner Ö, Altunbaşak Ş, Incecik F, Bişgin A, Ceylaner S. Congenital myasthenic syndrome in Turkey: clinical and genetic features in the long-term follow-up of patients. Acta Neurol Belg 2021; 121:529-534. [PMID: 31773638 DOI: 10.1007/s13760-019-01246-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 11/12/2019] [Indexed: 11/29/2022]
Abstract
Congenital Myasthenic Syndromes (CMS) are rare disorders that occur as a result of defects in the structure and in the function of neuromuscular junctions. Molecular genetic diagnosis is important to select the most suitable therapeutic option and treatment. Eight patients with congenital myasthenic syndromes who presented to the Çukurova University Pediatric Neurology Department Outpatient Clinic between June 2015 and May 2018 were reviewed. Mutations in the acetylcholine receptor (subunits in epsilon) (CHRNE) in three and mutations in the collagenic tail of endplate acetylcholinesterase (COLQ) gene in five patients were identified; p.W148 mutation was detected to be homozygous in four, c.1169A > G novel mutation in COLQ gene was homozygous in one, c452_454delAGG mutation was homozygous in the other patient, IVS7 + 2T > C(c.802 + 2T > C) mutation was homozygous in a patient and compound heterozygous mutations of c.865C > T(p.Leu289Phe) and c.872C > G(p.A2916)(p.Arg291Gly) in the CHRNE gene in the last patient. The parents of all the evaluated patients were consanguineous. Ptosis, ophthalmoplegia, generalized hypotonia, bulbar weakness, and respiratory crisis were the main findings at the time of presentation. Pyridostigmine is the first-line drug therapy in primary AChR deficiency. Beta adrenergic agonists, ephedrine, and albuterol are the other treatment options for CMS subtypes caused by mutations in COLQ. This study points out the genetic and phenotypic features of CMS patients in the Turkish population and it also reports previously unreported mutations in the literature. CHRNE and COLQ gene mutations are common in the Turkish population. Patients can get serious benefits and recover after the treatment. The treatment should be planned according to genetic tests and clinical findings.
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Affiliation(s)
- Gülen Gül Mert
- Department of Pediatrics, Division of Pediatric Neurology, Cukurova University, Adana, Turkey.
| | - Neslihan Özcan
- Department of Pediatrics, Division of Pediatric Neurology, Cukurova University, Adana, Turkey
| | - Özlem Hergüner
- Department of Pediatrics, Division of Pediatric Neurology, Cukurova University, Adana, Turkey
| | - Şakir Altunbaşak
- Department of Pediatrics, Division of Pediatric Neurology, Cukurova University, Adana, Turkey
| | - Faruk Incecik
- Department of Pediatrics, Division of Pediatric Neurology, Cukurova University, Adana, Turkey
| | - Atıl Bişgin
- Department of Medical Genetics, Cukurova University Faculty of Medicine, Adana, Turkey
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24
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Zhao Y, Li Y, Bian Y, Yao S, Liu P, Yu M, Zhang W, Wang Z, Yuan Y. Congenital myasthenic syndrome in China: genetic and myopathological characterization. Ann Clin Transl Neurol 2021; 8:898-907. [PMID: 33756069 PMCID: PMC8045908 DOI: 10.1002/acn3.51346] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 03/01/2021] [Accepted: 03/02/2021] [Indexed: 11/05/2022] Open
Abstract
OBJECTIVE We aimed to summarize the clinical, genetic, and myopathological features of a cohort of Chinese patients with congenital myasthenic syndrome, and follow up on therapeutic outcomes. METHODS The clinical spectrum, mutational frequency of genes, and pathological diagnostic clues of various subtypes of patients with congenital myasthenic syndrome were summarized. Therapeutic effects were followed up. RESULTS Thirty-five patients from 29 families were recruited. Ten genes were identified: GFPT1 (27.6%), AGRN (17.2%), CHRNE (17.2%), COLQ (13.8%), GMPPB (6.9%), CHAT, CHRNA1, DOK7, COG7, and SLC25A1 (3.4% each, respectively). Sole limb-girdle weakness was found in patients with AGRN (1/8) and GFPT1 (7/8) mutations, whereas distal weakness was all observed in patients with AGRN (6/8) mutations. Tubular aggregates were only found in patients with GFPT1 mutations (5/6). The patients with GMPPB mutations (2/2) had decreased alpha-dystroglycan. Acetylcholinesterase inhibitor therapy resulted in no response or worsened symptoms in patients with COLQ mutations, a diverse response in patients with AGRN mutations, and a good response in patients with other subtypes. Albuterol therapy was effective or harmless in most subtypes. Therapy effects became attenuated with long-term use in patients with COLQ or AGRN mutations. INTERPRETATION The genetic distribution of congenital myasthenic syndrome in China is distinct from that of other ethnic origins. The appearance of distal weakness, selective limb-girdle myasthenic syndrome, tubular aggregates, and decreased alpha-dystroglycan were indicative of the specific subtypes. Based on the follow-up findings, we suggest cautious evaluation of the long-term efficacy of therapeutic agents in congenital myasthenic syndrome.
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Affiliation(s)
- Yawen Zhao
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Ying Li
- Department of Neurology, Capital Medical University Affiliated Anzhen Hospital, Chaoyang-qu, China
| | - Yang Bian
- Department of Neurology, Sixth Medical Center of PLA General Hospital, Beijing, China
| | - Sheng Yao
- Department of Neurology, Sixth Medical Center of PLA General Hospital, Beijing, China
| | - Penju Liu
- Department of Neurology, Capital Medical University Affiliated Anzhen Hospital, Chaoyang-qu, China
| | - Meng Yu
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Wei Zhang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, Beijing, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, Beijing, China
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Joviano-Santos JV, Kljakic O, Magalhães-Gomes MPS, Valadão PAC, de Oliveira LR, Prado MAM, Prado VF, Guatimosim C. Motoneuron-specific loss of VAChT mimics neuromuscular defects seen in congenital myasthenic syndrome. FEBS J 2021; 288:5331-5349. [PMID: 33730374 DOI: 10.1111/febs.15825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 03/03/2021] [Accepted: 03/16/2021] [Indexed: 11/28/2022]
Abstract
Motoneurons (MNs) control muscle activity by releasing the neurotransmitter acetylcholine (ACh) at the level of neuromuscular junctions. ACh is packaged into synaptic vesicles by the vesicular ACh transporter (VAChT), and disruptions in its release can impair muscle contraction, as seen in congenital myasthenic syndromes (CMS). Recently, VAChT gene mutations were identified in humans displaying varying degrees of myasthenia. Moreover, mice with a global deficiency in VAChT expression display several characteristics of CMS. Despite these findings, little is known about how a long-term decrease in VAChT expression in vivo affects MNs structure and function. Using Cre-loxP technology, we generated a mouse model where VAChT is deleted in select groups of MNs (mnVAChT-KD). Molecular analysis revealed that the VAChT deletion was specific to MNs and affected approximately 50% of its population in the brainstem and spinal cord, with alpha-MNs primarily targeted (70% in spinal cord). Within each animal, the cell body area of VAChT-deleted MNs was significantly smaller compared to MNs with VAChT preserved. Likewise, muscles innervated by VAChT-deleted MNs showed atrophy while muscles innervated by VAChT-containing neurons appeared normal. In addition, mnVAChT KD mice had decreased muscle strength, were hypoactive, leaner and exhibited kyphosis. This neuromuscular dysfunction was evident at 2 months of age and became progressively worse by 6 months. Treatment of mutants with a cholinesterase inhibitor was able to improve some of the motor deficits. As these observations mimic what is seen in CMS, this new line could be valuable for assessing the efficacy of potential CMS drugs.
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Affiliation(s)
- Julliane V Joviano-Santos
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Ornela Kljakic
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada
| | - Matheus P S Magalhães-Gomes
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil.,Departamento de Medicina, Faculdade Ciências Médicas de Minas Gerais, FCMMG, Belo Horizonte, Brasil
| | - Priscila Aparecida C Valadão
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Leonardo R de Oliveira
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marco A M Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Brain and Mind Institute, University of Western Ontario, London, Canada
| | - Vania F Prado
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Canada.,Brain and Mind Institute, University of Western Ontario, London, Canada
| | - Cristina Guatimosim
- Departamento de Morfologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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Lehky T, Joseph R, Toro C, Wu T, Van Ryzin C, Gropman A, Facio FM, Webb BD, Jabs EW, Barry BS, Engle EC, Collins FS, Manoli I. Differentiating Moebius syndrome and other congenital facial weakness disorders with electrodiagnostic studies. Muscle Nerve 2021; 63:516-524. [PMID: 33389762 DOI: 10.1002/mus.27159] [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: 05/18/2020] [Revised: 12/18/2020] [Accepted: 12/24/2020] [Indexed: 01/11/2023]
Abstract
INTRODUCTION Congenital facial weakness (CFW) can result from facial nerve paresis with or without other cranial nerve and systemic involvement, or generalized neuropathic and myopathic disorders. Moebius syndrome is one type of CFW. In this study we explored the utility of electrodiagnostic studies (EDx) in the evaluation of individuals with CFW. METHODS Forty-three subjects enrolled prospectively into a dedicated clinical protocol and had EDx evaluations, including blink reflex and facial and peripheral nerve conduction studies, with optional needle electromyography. RESULTS MBS and hereditary congenital facial paresis (HCFP) subjects had low-amplitude cranial nerve 7 responses without other neuropathic or myopathic findings. Carriers of specific pathogenic variants in TUBB3 had, in addition, a generalized sensorimotor axonal polyneuropathy with demyelinating features. Myopathic findings were detected in individuals with Carey-Fineman-Ziter syndrome, myotonic dystrophy, other undefined myopathies, or CFW with arthrogryposis, ophthalmoplegia, and other system involvement. DISCUSSION EDx in CFW subjects can assist in characterizing the underlying pathogenesis, as well as guide diagnosis and genetic counseling.
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Affiliation(s)
- Tanya Lehky
- EMG Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Reversa Joseph
- EMG Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA.,Chalmers P. Wylie Veterans Administration, Columbus, Ohio, USA
| | - Camilo Toro
- Undiagnosed Disease Program, OCD, NHGRI, NIH, Bethesda, Maryland, USA
| | - Tianxia Wu
- Clinical Trials Unit, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Carol Van Ryzin
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Andrea Gropman
- Neurodevelopmental Pediatrics and Neurogenetics, Children's National Medical Center, Washington, District of Columbia, USA
| | - Flavia M Facio
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Bryn D Webb
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Ethylin W Jabs
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Brenda S Barry
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA
| | - Elizabeth C Engle
- Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA.,Howard Hughes Medical Institute, Chevy Chase, Maryland, USA.,Department of Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts, USA
| | - Francis S Collins
- Medical Genomics and Metabolic Genetics Branch, Immediate Office of the Director, National Institutes of Health, Bethesda, Maryland, USA
| | - Irini Manoli
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
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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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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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30
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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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31
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Matyushenko AM, Levitsky DI. Molecular Mechanisms of Pathologies of Skeletal and Cardiac Muscles Caused by Point Mutations in the Tropomyosin Genes. BIOCHEMISTRY (MOSCOW) 2020; 85:S20-S33. [PMID: 32087052 DOI: 10.1134/s0006297920140023] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The review is devoted to tropomyosin (Tpm) - actin-binding protein, which plays a crucial role in the regulation of contraction of skeletal and cardiac muscles. Special attention is paid to myopathies and cardiomyopathies - severe hereditary diseases of skeletal and cardiac muscles associated with point mutations in Tpm genes. The current views on the molecular mechanisms of these diseases and the effects of such mutations on the Tpm structure and functions are considered in detail. Besides, some part of the review is devoted to analysis of the properties of Tpm homodimers and heterodimers with myopathic substitutions of amino acid residues in only one of the two chains of the Tpm dimeric molecule.
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Affiliation(s)
- A M Matyushenko
- Bach Institute of Biochemistry, Federal Research Center on Fundamentals of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia.
| | - D I Levitsky
- Bach Institute of Biochemistry, Federal Research Center on Fundamentals of Biotechnology, Russian Academy of Sciences, Moscow, 119071, Russia. .,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
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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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Severe congenital myasthenic syndrome associated with novel biallelic mutation of the CHRND gene. Neuromuscul Disord 2020; 30:336-339. [DOI: 10.1016/j.nmd.2020.02.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Revised: 01/14/2020] [Accepted: 02/16/2020] [Indexed: 11/20/2022]
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Congenital myasthenic syndrome: Ten years clinical experience from a quaternary care south-Indian hospital. J Clin Neurosci 2019; 72:238-243. [PMID: 31889643 DOI: 10.1016/j.jocn.2019.11.030] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Accepted: 11/27/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND To ascertain the frequency, clinical spectrum and outcome of congenital myasthenic syndrome (CMS) patients who reported to the neuromuscular division of our quaternary medical center during the past ten years. METHODS We performed a retrospective analysis of all the CMS patients who reported to us during the study period. RESULTS Twenty-one patients of CMS attended our quaternary hospital over the past ten years. The median follow-up was 24 (IQR: 16.5-67.3) months. All the patients showed an overall improvement in the last follow up. The diagnosis of CMS could be genetically confirmed in seven cases. Four patients had COLQ mutation, two had CHRNε mutation and one had MUSK mutation. All the cases of COLQ mutation and one case of MUSK mutation had a limb-girdle (LG) presentation. Our study and review of literature imply that CMS should be suspected in cases of seronegative myasthenia gravis cases if the onset is at less than 20 years and strongly so if the onset is within the first two years of life. In addition, a positive family history, delayed motor milestones, and a poor response to immune-modulators should be actively sought for as indicators of CMS.
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A Novel c.973G>T Mutation in the ε-subunit of the Acetylcholine Receptor Causing Congenital Myasthenic Syndrome in an Iranian Family. Balkan J Med Genet 2019; 22:95-98. [PMID: 31523627 PMCID: PMC6714341 DOI: 10.2478/bjmg-2019-0010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Congenital myasthenic syndrome (CMS) constitutes a group of inherited disorders of neuromuscular junctions. The majority of postsynaptic syndromes result from mutations in the CHRNE gene that causes muscle nicotine acetylcholine deficiency. In this study, we report on a 2 and a half-year-old boy with normal developmental milestones and bilateral ptosis. Clinical courses, electrophysiological studies and molecular genetic analysis were assessed. Polymerase chain reaction (PCR) and direct DNA sequencing of the CHRNE gene were performed for the proband and all the family members. A novel homozygous missense mutation of c.973G>T was found in the CHRNE gene. Segregation studies were suggested to be the genetic cause of the disease. Using three in silico tools and the American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) variant classification guidelines indicated that the novel variant c.973G>T was likely pathogenic. Our results recommended first screening of the CHRNE gene for pathogenic mutations in Iranian origin.
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Abstract
INTRODUCTION Mutations in the Dok-7 gene (DOK7) underlie a congenital myasthenic syndrome (CMS) with a characteristic limb-girdle (LG) pattern of muscle weakness. Multiple clinical findings and a wide clinical heterogeneity have been identified in this form of CMS. METHODS We describe here 2 unrelated adult patients who presented with a LG CMS, caused by 2 compound heterozygous pathogenic sequence variants in DOK7: c.1124_1127dupTGCC (P.Ala378Serfs*30) and c.480C> A (p.Tyr160*). RESULTS Although both patients presented with severe proximal weakness consistent with LG myasthenia, one of the patients presented with additional distal muscle involvement in the lower extremities. By contrast, the other patient had severe bulbar and respiratory deficit requiring gastric tube feeding and mechanical ventilatory support for most parts of the day. DISCUSSION These 2 cases illustrate the lack of phenotype-genotype correlation and the absence of geographic, genetic, and ethnic association in cases of LG CMS caused by DOK7 mutations.
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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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Nicole S, Azuma Y, Bauché S, Eymard B, Lochmüller H, Slater C. Congenital Myasthenic Syndromes or Inherited Disorders of Neuromuscular Transmission: Recent Discoveries and Open Questions. J Neuromuscul Dis 2019; 4:269-284. [PMID: 29125502 PMCID: PMC5701762 DOI: 10.3233/jnd-170257] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Congenital myasthenic syndromes (CMS) form a heterogeneous group of rare diseases characterized by fatigable muscle weakness. They are genetically-inherited and caused by defective synaptic transmission at the cholinergic neuromuscular junction (NMJ). The number of genes known to cause CMS when mutated is currently 30, and the relationship between fatigable muscle weakness and defective functions is quite well-understood for many of them. However, some of the most recent discoveries in individuals with CMS challenge our knowledge of the NMJ, where the basis of the pathology has mostly been investigated in animal models. Frontier forms between CMS and congenital myopathy, which have been genetically and clinically identified, underline the poorly understood interplay between the synaptic and extrasynaptic molecules in the neuromuscular system. In addition, precise electrophysiological and histopathological investigations of individuals with CMS suggest an important role of NMJ plasticity in the response to CMS pathogenesis. While efficient drug-based treatments are already available to improve neuromuscular transmission for most forms of CMS, others, as well as neurological and muscular comorbidities, remain resistant. Taken together, the available pathological data point to physiological issues which remain to be understood in order to achieve precision medicine with efficient therapeutics for all individuals suffering from CMS.
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Affiliation(s)
- Sophie Nicole
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France
| | - Yoshiteru Azuma
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Stéphanie Bauché
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France
| | - Bruno Eymard
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Université Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France.,AP-HP, Hôpital Pitié-Salpétrière, 75013 Paris, France
| | - Hanns Lochmüller
- John Walton Muscular Dystrophy Research Centre, Institute of Genetic Medicine, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Clarke Slater
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK
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Afshar Bakooshli M, Lippmann ES, Mulcahy B, Iyer N, Nguyen CT, Tung K, Stewart BA, van den Dorpel H, Fuehrmann T, Shoichet M, Bigot A, Pegoraro E, Ahn H, Ginsberg H, Zhen M, Ashton RS, Gilbert PM. A 3D culture model of innervated human skeletal muscle enables studies of the adult neuromuscular junction. eLife 2019; 8:44530. [PMID: 31084710 PMCID: PMC6516829 DOI: 10.7554/elife.44530] [Citation(s) in RCA: 131] [Impact Index Per Article: 26.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 04/23/2019] [Indexed: 12/22/2022] Open
Abstract
Two-dimensional (2D) human skeletal muscle fiber cultures are ill-equipped to support the contractile properties of maturing muscle fibers. This limits their application to the study of adult human neuromuscular junction (NMJ) development, a process requiring maturation of muscle fibers in the presence of motor neuron endplates. Here we describe a three-dimensional (3D) co-culture method whereby human muscle progenitors mixed with human pluripotent stem cell-derived motor neurons self-organize to form functional NMJ connections. Functional connectivity between motor neuron endplates and muscle fibers is confirmed with calcium imaging and electrophysiological recordings. Notably, we only observed epsilon acetylcholine receptor subunit protein upregulation and activity in 3D co-cultures. Further, 3D co-culture treatments with myasthenia gravis patient sera shows the ease of studying human disease with the system. Hence, this work offers a simple method to model and evaluate adult human NMJ de novo development or disease in culture.
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Affiliation(s)
- Mohsen Afshar Bakooshli
- Donnelly Centre, University of Toronto, Toronto, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada
| | - Ethan S Lippmann
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, United States.,Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, United States
| | - Ben Mulcahy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada
| | - Nisha Iyer
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, United States.,Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, United States
| | - Christine T Nguyen
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada
| | - Kayee Tung
- Department of Surgery, University of Toronto, Toronto, Canada
| | - Bryan A Stewart
- Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Biology, University of Toronto Mississauga, Mississauga, Canada
| | - Hubrecht van den Dorpel
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.,Department of Pharmaceutics, Utrecht University, Utrecht, Netherlands
| | - Tobias Fuehrmann
- Donnelly Centre, University of Toronto, Toronto, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Molly Shoichet
- Donnelly Centre, University of Toronto, Toronto, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.,Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Canada
| | - Anne Bigot
- INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, Sorbonne Universite, Paris, France
| | - Elena Pegoraro
- Department of Neuroscience, University of Padova, Padova, Italy
| | - Henry Ahn
- Department of Surgery, University of Toronto, Toronto, Canada.,Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada
| | - Howard Ginsberg
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.,Department of Surgery, University of Toronto, Toronto, Canada.,Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Canada.,Department of Physiology, University of Toronto, Toronto, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Canada
| | - Randolph Scott Ashton
- Department of Biomedical Engineering, University of Wisconsin-Madison, Madison, United States.,Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, United States
| | - Penney M Gilbert
- Donnelly Centre, University of Toronto, Toronto, Canada.,Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Canada.,Department of Cell and Systems Biology, University of Toronto, Toronto, Canada.,Department of Biochemistry, University of Toronto, Toronto, Canada
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Mansukhani SA, Bothun ED, Diehl NN, Mohney BG. Incidence and Ocular Features of Pediatric Myasthenias. Am J Ophthalmol 2019; 200:242-249. [PMID: 30653958 PMCID: PMC6587184 DOI: 10.1016/j.ajo.2019.01.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2018] [Revised: 01/05/2019] [Accepted: 01/05/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE To report the incidence, demographics, and ocular findings of children with myasthenia. DESIGN Retrospective cohort study. METHODS The medical records of all children (<19 years) examined at Mayo Clinic with any form of myasthenia from January 1 1966, through December 31, 2015, were retrospectively reviewed. RESULTS A total of 364 children were evaluated during the study period, of which 6 children were residents of the Olmsted County at the time of their diagnosis, yielding an annual age- and sex-adjusted incidence of 0.35 per 100 000 <19 years, or 1 in 285 714 <19 years. The incidence of juvenile myasthenia gravis (JMG) and congenital myasthenic syndrome (CMS) was 0.12 and 0.23 per 100 000, respectively. Of the 364 study children, 217 (59.6%) had JMG, 141 (38.7%) had CMS, and 6 (1.7%) had Lambert-Eaton syndrome, diagnosed at a median age of 13.5, 5.1, and 12.6 years, respectively. A majority of the JMG and CMS patients had ocular involvement (90.3% and 85.1%, respectively), including ptosis and ocular movement deficits. Among children with at least 1 year of follow-up (JMG; median, 7.1 years, CMS; median, 7.0 years), improvement was seen in 88.8% of JMG patients (complete remission in 31.3%) and in 58.3% of CMS patients. CONCLUSION Although relatively rare, myasthenia gravis in children has 2 predominant forms, CMS and JMG, both of which commonly have ocular involvement. Improvement is more likely in children with the juvenile form.
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Wadwekar V, Pillai RR, Sesh S, Nair SS, Nair M. Pregnancy-associated respiratory failure in muscle specific kinase congenital myasthenic syndrome. Muscle Nerve 2019; 59:E24-E26. [PMID: 30635923 DOI: 10.1002/mus.26410] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 12/19/2018] [Accepted: 12/22/2018] [Indexed: 11/07/2022]
Affiliation(s)
- Vaibhav Wadwekar
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
| | - Rajit Remanan Pillai
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
| | - S Sesh
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
| | - Sruthi S Nair
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
| | - Muralidharan Nair
- Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum, India
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42
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Italian recommendations for diagnosis and management of congenital myasthenic syndromes. Neurol Sci 2018; 40:457-468. [PMID: 30554356 DOI: 10.1007/s10072-018-3682-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/10/2018] [Indexed: 12/11/2022]
Abstract
Congenital myasthenic syndromes (CMS) are genetic disorders due to mutations in genes encoding proteins involved in the neuromuscular junction structure and function. CMS usually present in young children, but perinatal and adult onset has been reported. Clinical presentation is highly heterogeneous, ranging from mild symptoms to severe manifestations, sometimes with life-threatening respiratory episodes, especially in the first decade of life. Although considered rare, CMS are probably underestimated due to diagnostic difficulties. Because of the several therapeutic opportunities, CMS should be always considered in the differential diagnosis of neuromuscular disorders. The Italian Network on CMS proposes here recommendations for proper CMS diagnosis and management, aiming to guide clinicians in their practical approach to CMS patients.
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Angelini C, Lispi L, Salvoro C, Mostacciuolo ML, Vazza G. Clinical and genetic characterization of an Italian family with slow-channel syndrome. Neurol Sci 2018; 40:503-507. [PMID: 30542963 DOI: 10.1007/s10072-018-3645-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Accepted: 11/09/2018] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The slow-channel congenital myasthenic syndrome (SCCMS) is a postsynaptic form of congenital myasthenic syndromes (CMSs), a clinically heterogeneous group of disorders caused by genetic defects leading to an abnormal signal transmission at the endplate. METHODS We report clinical and molecular data of a multigenerational family in which the presentation of a progressive proximal-distal weakness with ocular involvement led to a number of different clinical diagnoses. RESULTS A comprehensive genetic study which included whole-genome linkage analysis and whole-exome sequencing identified a heterozygous missense substitution (c.721C>T, p.L241F) in the ε subunit of the acetylcholine receptor (CHRNE) that was consistent with clinical weakness in all patients. DISCUSSION SCCMS is characterized by a broad and heterogeneous clinical phenotype in which disease onset, symptoms, severity, and progression can be highly variable even between family members. The identification of a CHRNE mutation allowed to make the definitive diagnosis of CMS in this family and contributed to define the clinical spectrum of this disease.
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Affiliation(s)
- Corrado Angelini
- Fondazione Hospital S.Camillo Institute for Research and Health Care, Venice, Italy.
| | - Ludovico Lispi
- Neurology and Neurophysiopathology Unit, ASO San Camillo-Forlanini Hospital of Rome, Rome, Italy
| | | | | | - Giovanni Vazza
- Department of Biology, University of Padova, Padova, Italy
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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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45
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Estephan EDP, Zambon AA, Marchiori PE, da Silva AMS, Caldas VM, Moreno CAM, Reed UC, Horvath R, Töpf A, Lochmüller H, Zanoteli E. Clinical variability of early-onset congenital myasthenic syndrome due to biallelic RAPSN mutations in Brazil. Neuromuscul Disord 2018; 28:961-964. [DOI: 10.1016/j.nmd.2018.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 08/22/2018] [Indexed: 10/28/2022]
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Kumar A, Asghar S, Kavanagh R, Wicklund MP. Unique presentation of rapidly fluctuating symptoms in a child with congenital myasthenic syndrome due to RAPSN mutation. Muscle Nerve 2018; 58:E23-E24. [PMID: 30028532 DOI: 10.1002/mus.26200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 06/09/2018] [Accepted: 06/12/2018] [Indexed: 10/28/2022]
Affiliation(s)
- Ashutosh Kumar
- Division of Pediatric Neurology, Penn State Milton S. Hershey Medical Center, 500 University Drive, Hershey, Pennsylvania, 17033, USA
| | - Sheila Asghar
- Division of Pediatric Neurology, Penn State Milton S. Hershey Medical Center, 500 University Drive, Hershey, Pennsylvania, 17033, USA
| | - Robert Kavanagh
- Division of Pediatric Critical Care, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Matthew P Wicklund
- Department of Neurology, University of Colorado School of Medicine, Aurora, Colorado, USA
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47
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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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Durmus H, Shen XM, Serdaroglu-Oflazer P, Kara B, Parman-Gulsen Y, Ozdemir C, Brengman J, Deymeer F, Engel AG. Congenital myasthenic syndromes in Turkey: Clinical clues and prognosis with long term follow-up. Neuromuscul Disord 2018; 28:315-322. [PMID: 29395675 PMCID: PMC5924610 DOI: 10.1016/j.nmd.2017.11.013] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Revised: 11/07/2017] [Accepted: 11/20/2017] [Indexed: 11/28/2022]
Abstract
Congenital myasthenic syndromes (CMS) are a group of hereditary disorders affecting the neuromuscular junction. Here, we present clinical, electrophysiological and genetic findings of 69 patients from 51 unrelated kinships from Turkey. Genetic tests of 60 patients were performed at Mayo Clinic. Median follow-up time was 9.8 years (range 1-22 years). The most common CMS was primary acetylcholine receptor (AChR) deficiency (31/51) and the most common mutations in AChR were c.1219 + 2T > G (12/51) and c.1327delG (6/51) in CHRNE. Four of our 5 kinships with AChE deficiency carried p.W148X that truncates the collagen domain of COLQ, and was previously reported only in patients from Turkey. These were followed by GFPT1 deficiency (4/51), DOK7 deficiency (3/51), slow channel CMS (3/51), fast channel CMS (3/51), choline acetyltransferase deficiency (1/51) and a CMS associated with desmin deficiency (1/51). Distribution of muscle weakness was sometimes useful in giving a clue to the CMS subtype. Presence of repetitive compound muscle action potentials pointed to AChE deficiency or slow channel CMS. Our experience confirms that one needs to be cautious using pyridostigmine, since it can worsen some types of CMS. Ephedrine/salbutamol were very effective in AChE and DOK7 deficiencies and were useful as adjuncts in other types of CMS. Long follow-up gave us a chance to assess progression of the disease, and to witness 12 mainly uneventful pregnancies in 8 patients. In this study, we describe some new phenotypes and detail the clinical features of the well-known CMS.
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Affiliation(s)
- Hacer Durmus
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Capa, 34390, Istanbul, Turkey
| | - Xin-Ming Shen
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Piraye Serdaroglu-Oflazer
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Capa, 34390, Istanbul, Turkey
| | - Bulent Kara
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Capa, 34390, Istanbul, Turkey
| | - Yesim Parman-Gulsen
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Capa, 34390, Istanbul, Turkey
| | - Coskun Ozdemir
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Capa, 34390, Istanbul, Turkey
| | - Joan Brengman
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Feza Deymeer
- Department of Neurology, Istanbul Medical Faculty, Istanbul University, Capa, 34390, Istanbul, Turkey.
| | - Andrew G Engel
- Department of Neurology, Mayo Clinic, Rochester, MN, USA
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Estephan EDP, Sobreira CFDR, Dos Santos ACJ, Tomaselli PJ, Marques W, Ortega RPM, Costa MCM, da Silva AMS, Mendonça RH, Caldas VM, Zambon AA, Abath Neto O, Marchiori PE, Heise CO, Reed UC, Azuma Y, Töpf A, Lochmüller H, Zanoteli E. A common CHRNE mutation in Brazilian patients with congenital myasthenic syndrome. J Neurol 2018; 265:708-713. [PMID: 29383513 PMCID: PMC7115868 DOI: 10.1007/s00415-018-8736-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 12/16/2017] [Accepted: 01/04/2018] [Indexed: 11/29/2022]
Abstract
The most common causes of congenital myasthenic syndromes (CMS) are CHRNE mutations, and some pathogenic allelic variants in this gene are especially frequent in certain ethnic groups. In the southern region of Brazil, a study found the c.130dupG CHRNE mutation in up to 33% of families with CMS. Here, we aimed to verify the frequency of this mutation among individuals with CMS in a larger cohort of CMS patients from different areas of Brazil and to characterize clinical features of these patients. Eighty-four patients with CMS, from 72 families, were clinically evaluated and submitted to direct sequencing of the exon 2 of CHRNE. The c.130dupG mutation was found in 32 patients (23 families), with 26 patients (19 families, 26.3%) in homozygosis, confirming its high prevalence in different regions of Brazil. Among the homozygous patients, the following characteristics were frequent: onset of symptoms before 2 years of age (92.3%), little functional restriction (92.3%), fluctuating symptoms (100%), ocular muscle impairment (96.1%), ptosis (100%), limb weakness (88.4%), response to pyridostigmine (100%), facial involvement (77%), and bulbar symptoms (70.8%). The pretest probability of finding at least one allele harbouring the c.130dupG mutation was 38.1%. Selecting only patients with impaired eye movement together with limb weakness and improvement with pyridostigmine, the probability increases to 72.2%. This clinical pre-selection of patients is likely a useful tool for regions where CHRNE mutations have a founder effect. In conclusion, the CHRNE mutation c.130dupG leads to fairly benign natural course of the disease with relative homogeneity.
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Affiliation(s)
- Eduardo de Paula Estephan
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | | | | | - Pedro José Tomaselli
- Department of Neurosciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | - Wilson Marques
- Department of Neurosciences, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, SP, Brazil
| | | | | | - André Macedo Serafim da Silva
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Rodrigo Holanda Mendonça
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Vitor Marques Caldas
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Antonio Alberto Zambon
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Osório Abath Neto
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Paulo Eurípedes Marchiori
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Carlos Otto Heise
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Umbertina Conti Reed
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil
| | - Yoshiteru Azuma
- Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Ana Töpf
- Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Hanns Lochmüller
- Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, NE1 3BZ, UK
| | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), Av. Enéas de Carvalho Aguiar, 255, 5o andar, sala 5084, Cerqueira César, São Paulo, 05403-900, Brazil.
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O'Connor E, Töpf A, Zahedi RP, Spendiff S, Cox D, Roos A, Lochmüller H. Clinical and research strategies for limb-girdle congenital myasthenic syndromes. Ann N Y Acad Sci 2018; 1412:102-112. [PMID: 29315608 DOI: 10.1111/nyas.13520] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/05/2017] [Accepted: 09/12/2017] [Indexed: 12/21/2022]
Abstract
Congenital myasthenic syndromes (CMS) are a group of rare disorders that cause fatigable muscle weakness due to defective signal transmission at the neuromuscular junction, a specialized synapse between peripheral motor neurons and their target muscle fibers. There are now over 30 causative genes that have been reported for CMS. Of these, there are 10 that are associated with a limb-girdle pattern of muscle weakness and are thus classed as LG-CMS. Next-generation sequencing and advanced methods of data sharing are likely to uncover further genes that are associated with similar clinical phenotypes, contributing to better diagnosis and effective treatment of LG-CMS patients. This review highlights clinical and pathological hallmarks of LG-CMS in relation to the underlying genetic defects and pathways. Tailored animal and cell models are essential to elucidate the exact function and pathomechanisms at the neuromuscular synapse that underlie LG-CMS. The integration of genomics and proteomics data derived from these models and patients reveals new and often unexpected insights that are relevant beyond the rare genetic disorder of LG-CMS and may extend to the functioning of mammalian synapses in health and disease more generally.
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Affiliation(s)
- Emily O'Connor
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Ana Töpf
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - René P Zahedi
- Leibniz-Institut für Analytische Wissenschaften, ISAS e.V., Dortmund, Germany
| | - Sally Spendiff
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Daniel Cox
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | - Andreas Roos
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK.,Leibniz-Institut für Analytische Wissenschaften, ISAS e.V., Dortmund, Germany
| | - Hanns Lochmüller
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
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