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Zhang C, Jian L, Li X, Guo W, Deng W, Hu X, Li T. Mendelian randomization analysis of the brain, cerebrospinal fluid, and plasma proteome identifies potential drug targets for attention deficit hyperactivity disorder. EBioMedicine 2024; 105:105197. [PMID: 38876042 PMCID: PMC11225168 DOI: 10.1016/j.ebiom.2024.105197] [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: 01/13/2024] [Revised: 05/26/2024] [Accepted: 05/29/2024] [Indexed: 06/16/2024] Open
Abstract
BACKGROUND The need for new therapeutics for attention deficit hyperactivity disorder (ADHD) is evident. Brain, cerebrospinal fluid (CSF), and plasma protein biomarkers with causal genetic evidence could represent potential drug targets. However, a comprehensive screen of the proteome has not yet been conducted. METHODS We employed a three-pronged approach using Mendelian Randomization (MR) and Bayesian colocalization analysis. Firstly, we studied 608 brains, 214 CSF, and 612 plasma proteins as potential causal mediators of ADHD using MR analysis. Secondly, we analysed the consistency of the discovered biomarkers across three distinct subtypes of ADHD: childhood, persistent, and late-diagnosed ADHD. Finally, we extended our analysis to examine the correlation between identified biomarkers and Tourette syndrome and pervasive autism spectrum disorder (ASD), conditions often linked with ADHD. To validate the MR findings, we conducted sensitivity analysis. Additionally, we performed cell type analysis on the human brain to identify risk genes that are notably enriched in various brain cell types. FINDINGS After applying Bonferroni correction, we found that the risk of ADHD was increased by brain proteins GMPPB, NAA80, HYI, CISD2, and HYI, TIE1 in CSF and plasma. Proteins GMPPB, NAA80, ICA1L, CISD2, TIE1, and RMDN1 showed overlapped loci with ADHD risk through Bayesian colocalization. Overexpression of GMPPB protein was linked to an increase in the risk for all three ADHD subtypes. While ICA1L provided protection against both ASD and ADHD, CISD2 increased the probability of both disorders. Cell-specific studies revealed that GMPPB, NAA80, ICA1L, and CISD2 were predominantly present on the surface of excitatory-inhibitory neurons. INTERPRETATION Our comprehensive MR investigation of the brain, CSF, and plasma proteomes revealed seven proteins with causal connections to ADHD. Particularly, GMPPB and TIE1 emerged as intriguing targets for potential ADHD therapy. FUNDING This work was partly funded by the Key R & D Program of Zhejiang (T.L. 2022C03096); the National Natural Science Foundation of China Project (C.Z. 82001413); Postdoctoral Foundation of West China Hospital (C.Z. 2020HXBH163).
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Affiliation(s)
- Chengcheng Zhang
- Mental Health Center and Psychiatric Laboratory, The State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
| | - Lingqi Jian
- Mental Health Center and Psychiatric Laboratory, The State Key Laboratory of Biotherapy, West China Hospital of Sichuan University, Chengdu, 610041, Sichuan, China
| | - Xiaojing Li
- Affiliated Mental Health Center & Hangzhou Seventh People's Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Wanjun Guo
- Affiliated Mental Health Center & Hangzhou Seventh People's Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Wei Deng
- Affiliated Mental Health Center & Hangzhou Seventh People's Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China
| | - Xun Hu
- The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, 310058, China
| | - Tao Li
- Affiliated Mental Health Center & Hangzhou Seventh People's Hospital and School of Brain Science and Brain Medicine, Zhejiang University School of Medicine, Hangzhou, 310058, China; Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, 1369 West Wenyi Road, Hangzhou, 311121, China; NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou, 310058, China.
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Franzka P, Mittag S, Chakraborty A, Huber O, Hübner CA. Ubiquitination contributes to the regulation of GDP-mannose pyrophosphorylase B activity. Front Mol Neurosci 2024; 17:1375297. [PMID: 38979475 PMCID: PMC11228364 DOI: 10.3389/fnmol.2024.1375297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 05/31/2024] [Indexed: 07/10/2024] Open
Abstract
GDP-mannose pyrophosphorylase B (GMPPB) loss-of-function is associated with muscular dystrophy and variable additional neurological symptoms. GMPPB facilitates the catalytic conversion of mannose-1-phosphate and GTP to GDP-mannose, which serves as a mannose donor for glycosylation. The activity of GMPPB is regulated by its non-catalytic paralogue GMPPA, which can bind GDP-mannose and interact with GMPPB, thereby acting as an allosteric feedback inhibitor of GMPPB. Using pulldown, immunoprecipitation, turnover experiments as well as immunolabeling and enzyme activity assays, we provide first direct evidence that GMPPB activity is regulated by ubiquitination. We further show that the E3 ubiquitin ligase TRIM67 interacts with GMPPB and that knockdown of TRM67 reduces ubiquitination of GMPPB, thus reflecting a candidate E3 ligase for the ubiquitination of GMPPB. While the inhibition of GMPPB ubiquitination decreases its enzymatic activity, its ubiquitination neither affects its interaction with GMPPA nor its turnover. Taken together, we show that the ubiquitination of GMPPB represents another level of regulation of GDP-mannose supply.
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Affiliation(s)
- Patricia Franzka
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Sonnhild Mittag
- Department of Biochemistry II, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Abhijnan Chakraborty
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Otmar Huber
- Department of Biochemistry II, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Christian A Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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3
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Martínez Duncker I, Mata-Salgado D, Shammas I, Ranatunga W, Daniel EJP, Cruz Muñoz ME, Abreu M, Mora-Montes H, He M, Morava E, Zafra de la Rosa G. Case report: Novel genotype of ALG2-CDG and confirmation of the heptasaccharide glycan (NeuAc-Gal-GlcNAc-Man2-GlcNAc2) as a specific diagnostic biomarker. Front Genet 2024; 15:1363558. [PMID: 38770420 PMCID: PMC11102957 DOI: 10.3389/fgene.2024.1363558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2023] [Accepted: 04/08/2024] [Indexed: 05/22/2024] Open
Abstract
This report outlines the case of a child affected by a type of congenital disorder of glycosylation (CDG) known as ALG2-CDG (OMIM 607906), presenting as a congenital myasthenic syndrome (CMS) caused by variants identified in ALG2, which encodes an α1,3-mannosyltransferase (EC 2.4.1.132) involved in the early steps of N-glycosylation. To date, fourteen cases of ALG2-CDG have been documented worldwide. From birth, the child experienced perinatal asphyxia, muscular weakness, feeding difficulties linked to an absence of the sucking reflex, congenital hip dislocation, and hypotonia. Over time, additional complications emerged, such as inspiratory stridor, gastroesophageal reflux, low intake, recurrent seizures, respiratory infections, an inability to maintain the head upright, and a global developmental delay. Whole genome sequencing (WGS) revealed the presence of two ALG2 variants in compound heterozygosity: a novel variant c.1055_1056delinsTGA p.(Ser352Leufs*3) and a variant of uncertain significance (VUS) c.964C>A p.(Pro322Thr). Additional studies, including determination of carbohydrate-deficient transferrin (CDT) revealed a mild type I CDG pattern and the presence of an abnormal transferrin glycoform containing a linear heptasaccharide consisting of one sialic acid, one galactose, one N-acetyl-glucosamine, two mannoses and two N-acetylglucosamines (NeuAc-Gal-GlcNAc-Man2-GlcNAc2), ALG2-CDG diagnostic biomarker, confirming the pathogenicity of these variants.
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Affiliation(s)
- Ivan Martínez Duncker
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Denisse Mata-Salgado
- Laboratorio de Glicobiología Humana y Diagnóstico Molecular, Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Ibrahim Shammas
- Department of Clinical Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Wasantha Ranatunga
- Department of Clinical Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Earnest James Paul Daniel
- Palmieri Metabolic Disease Laboratory, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Mario E. Cruz Muñoz
- Laboratorio de Inmunología Molecular, Facultad de Medicina, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | | | - Héctor Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Guanajuato, Mexico
| | - Miao He
- Palmieri Metabolic Disease Laboratory, Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Eva Morava
- Department of Clinical Genomics, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
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Schurig MK, Umeh O, Henze H, Jung MJ, Gresing L, Blanchard V, von Maltzahn J, Hübner CA, Franzka P. Consequences of GMPPB deficiency for neuromuscular development and maintenance. Front Mol Neurosci 2024; 17:1356326. [PMID: 38419795 PMCID: PMC10899408 DOI: 10.3389/fnmol.2024.1356326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Accepted: 01/30/2024] [Indexed: 03/02/2024] Open
Abstract
Guanosine diphosphate-mannose pyrophosphorylase B (GMPPB) catalyzes the conversion of mannose-1-phosphate and GTP to GDP-mannose, which is required as a mannose donor for the biosynthesis of glycan structures necessary for proper cellular functions. Mutations in GMPPB have been associated with various neuromuscular disorders such as muscular dystrophy and myasthenic syndromes. Here, we report that GMPPB protein abundance increases during brain and skeletal muscle development, which is accompanied by an increase in overall protein mannosylation. To model the human disorder in mice, we generated heterozygous GMPPB KO mice using CIRSPR/Cas9. While we were able to obtain homozygous KO mice from heterozygous matings at the blastocyst stage, homozygous KO embryos were absent beyond embryonic day E8.5, suggesting that the homozygous loss of GMPPB results in early embryonic lethality. Since patients with GMPPB loss-of-function manifest with neuromuscular disorders, we investigated the role of GMPPB in vitro. Thereby, we found that the siRNA-mediated knockdown of Gmppb in either primary myoblasts or the myoblast cell line C2C12 impaired myoblast differentiation and resulted in myotube degeneration. siRNA-mediated knockdown of Gmppb also impaired the neuron-like differentiation of N2A cells. Taken together, our data highlight the essential role of GMPPB during development and differentiation, especially in myogenic and neuronal cell types.
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Affiliation(s)
- Mona K. Schurig
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Obinna Umeh
- Institute of Diagnostic Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Henriette Henze
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - M. Juliane Jung
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
| | - Lennart Gresing
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
| | - Véronique Blanchard
- Institute of Diagnostic Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
- Department of Human Medicine, Medical School Berlin, Berlin, Germany
| | - Julia von Maltzahn
- Leibniz Institute on Aging - Fritz Lipmann Institute, Jena, Germany
- Stem Cell Biology of Aging, Faculty of Health Sciences, Brandenburg Technische Universität Cottbus-Senftenberg, Senftenberg, Germany
| | - Christian A. Hübner
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
- Center of Rare Diseases, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
| | - Patricia Franzka
- Institute of Human Genetics, Jena University Hospital, Friedrich Schiller University, Jena, Germany
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5
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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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Ding JH, Xiao Y, Yang F, Song XQ, Xu Y, Ding XH, Ding R, Shao ZM, Di GH, Jiang YZ. Guanosine diphosphate-mannose suppresses homologous recombination repair and potentiates antitumor immunity in triple-negative breast cancer. Sci Transl Med 2024; 16:eadg7740. [PMID: 38170790 DOI: 10.1126/scitranslmed.adg7740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Accepted: 11/29/2023] [Indexed: 01/05/2024]
Abstract
Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with poor prognosis. TNBCs with high homologous recombination deficiency (HRD) scores benefit from DNA-damaging agents, including platinum drugs and poly(ADP-ribose) polymerase (PARP) inhibitors, whereas those with low HRD scores still lack therapeutic options. Therefore, we sought to exploit metabolic alterations to induce HRD and sensitize DNA-damaging agents in TNBCs with low HRD scores. We systematically analyzed TNBC metabolomics and identified a metabolite, guanosine diphosphate (GDP)-mannose (GDP-M), that impeded homologous recombination repair (HRR). Mechanistically, the low expression of the upstream enzyme GDP-mannose-pyrophosphorylase-A (GMPPA) led to the endogenous up-regulation of GDP-M in TNBC. The accumulation of GDP-M in tumor cells further reduced the interaction between breast cancer susceptibility gene 2 (BRCA2) and ubiquitin-specific peptidase 21 (USP21), which promoted the ubiquitin-mediated degradation of BRCA2 to inhibit HRR. Therapeutically, we illustrated that the supplementation of GDP-M sensitized DNA-damaging agents to impair tumor growth in both in vitro (cancer cell line and patient-derived organoid) and in vivo (xenograft in immunodeficient mouse) models. Moreover, the combination of GDP-M with DNA-damaging agents activated STING-dependent antitumor immunity in immunocompetent syngeneic mouse models. Therefore, GDP-M supplementation combined with PARP inhibition augmented the efficacy of anti-PD-1 antibodies. Together, these findings suggest that GDP-M is a crucial HRD-related metabolite and propose a promising therapeutic strategy for TNBCs with low HRD scores using the combination of GDP-M, PARP inhibitors, and anti-PD-1 immunotherapy.
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Affiliation(s)
- Jia-Han Ding
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
- Human Phenome Institute, Zhangjiang Fudan International Innovation Center, Fudan University, Shanghai 201203, P. R. China
| | - Yi Xiao
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Fan Yang
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Xiao-Qing Song
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Ying Xu
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Xiao-Hong Ding
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Rui Ding
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Zhi-Ming Shao
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Gen-Hong Di
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
| | - Yi-Zhou Jiang
- Key Laboratory of Breast Cancer in Shanghai, Department of Breast Surgery, Fudan University Shanghai Cancer Center; Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P. R. China
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7
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Rathore G, Kang PB. Pediatric Neuromuscular Diseases. Pediatr Neurol 2023; 149:1-14. [PMID: 37757659 DOI: 10.1016/j.pediatrneurol.2023.08.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 07/25/2023] [Accepted: 08/24/2023] [Indexed: 09/29/2023]
Abstract
The diagnostic and referral workflow for children with neuromuscular disorders is evolving, particularly as newborn screening programs are expanding in tandem with novel therapeutic developments. However, for the children who present with symptoms and signs of potential neuromuscular disorders, anatomic localization, guided initially by careful history and physical examination, continues to be the cardinal initial step in the diagnostic evaluation. It is important to consider whether the localization is more likely to be in the lower motor neuron, peripheral nerve, neuromuscular junction, or muscle. After that, disease etiologies can be divided broadly into inherited versus acquired categories. Considerations of localization and etiologies will help generate a differential diagnosis, which in turn will guide diagnostic testing. Once a diagnosis is made, it is important to be aware of current treatment options, as a number of new therapies for some of these disorders have been approved in recent years. Families are also increasingly interested in clinical research, which may include natural history studies and interventional clinical trials. Such research has proliferated for rare neuromuscular diseases, leading to exciting advances in diagnostic and therapeutic technologies, promising dramatic changes in the landscape of these disorders in the years to come.
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Affiliation(s)
- Geetanjali Rathore
- Division of Neurology, Department of Pediatrics, University of Nebraska College of Medicine, Omaha, Nebraska
| | - Peter B Kang
- Paul and Sheila Wellstone Muscular Dystrophy Center and Department of Neurology, University of Minnesota Medical School, Minneapolis, Minnesota; Institute for Translational Neuroscience, University of Minnesota, Minneapolis, Minnesota.
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8
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Jewett G, Beland B, Khayambashi S, Silverstein S, Donkervoort S, Bönnemann CG, Pfeffer G, Chhibber S. Recessive Pathogenic GMPPB Variants Cause a Childhood Onset Myasthenic Syndrome Responsive to Pyridostigmine. Can J Neurol Sci 2023:1-3. [PMID: 37681231 DOI: 10.1017/cjn.2023.277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Affiliation(s)
- Gordon Jewett
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Benjamin Beland
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Shahin Khayambashi
- Department of Internal Medicine, Division of Neurology, University of British Columbia, Vancouver, BC, Canada
| | - Sarah Silverstein
- Rutgers New Jersey Medical School, Newark, NJ, USA
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Gerald Pfeffer
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Sameer Chhibber
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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9
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Salam MAE, Salama K, Selim YMM, Saad M, Rady R, Alawbathani S, Schroeder S, Elmonem MA, Elkhateeb N. Three siblings with variable degrees of neuromuscular involvement and congenital sideroblastic anemia: A peculiar phenotype and a surprise genotypic explanation. Ann Hum Genet 2023. [PMID: 36916508 DOI: 10.1111/ahg.12505] [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: 10/07/2022] [Revised: 02/22/2023] [Accepted: 02/26/2023] [Indexed: 03/16/2023]
Abstract
INTRODUCTION Congenital sideroblastic anemias (CSAs) are a group of inherited bone-marrow disorders manifesting with erythroid hyperplasia and ineffective erythropoiesis. METHODS We describe a detailed clinical and genetic characterization of three siblings with CSA. RESULTS Two of them had limb-girdle myopathy and global developmental delay. The two elder siblings performed allogenic hematopoietic stem-cell transplantation 5 and 3 years prior with stabilization of the hematological features. Exome sequencing in the non-transplanted sibling revealed a novel homozygous nonsense variant in SLC25A38 gene NM_017875.2:c.559C > T; p.(Arg187*) causing autosomal-recessive sideroblastic anemia type-2, and a second homozygous pathogenic previously reported variant in GMPPB gene NM_013334.3:c.458C > T; p.(Thr153Ile) causing autosomal-recessive muscular dystrophy-dystroglycanopathy type B14. With the established diagnosis, hematopoietic stem cell transplantation is now being scheduled for the youngest sibling, and a trial therapy with acetylcholine esterase inhibitors was started for the two neurologically affected patients with partial clinical improvement. CONCLUSION This family emphasizes the importance of whole-exome sequencing for familial cases with complex phenotypes and vague neurological manifestations.
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Affiliation(s)
- Mai Abd El Salam
- Department of Pediatrics (Pediatric Hematology Unit), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Khaled Salama
- Department of Pediatrics (Pediatric Hematology Unit), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Yasmeen M M Selim
- Department of Pediatrics (Pediatric Hematology Unit), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Mariam Saad
- Department of Pediatrics (Pediatric Hematology Unit), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | - Rasha Rady
- Department of Pediatrics (Pediatric Hematology Unit), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt
| | | | | | - Mohamed A Elmonem
- Department of Clinical and Chemical Pathology, Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt.,Egypt Center for Research and Regenerative Medicine (ECRRM), Cairo, Egypt
| | - Nour Elkhateeb
- Department of Pediatrics (Pediatric Neurology and Metabolic Medicine Unit), Kasr Alainy Faculty of Medicine, Cairo University, Cairo, Egypt.,Department of Clinical Genetics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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10
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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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11
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FitzHugh ZT, Schiller MR. Systematic Assessment of Protein C-Termini Mutated in Human Disorders. Biomolecules 2023; 13:biom13020355. [PMID: 36830724 PMCID: PMC9953674 DOI: 10.3390/biom13020355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/23/2023] [Accepted: 02/02/2023] [Indexed: 02/16/2023] Open
Abstract
All proteins have a carboxyl terminus, and we previously summarized eight mutations in binding and trafficking sequence determinants in the C-terminus that, when disrupted, cause human diseases. These sequence elements for binding and trafficking sites, as well as post-translational modifications (PTMs), are called minimotifs or short linear motifs. We wanted to determine how frequently mutations in minimotifs in the C-terminus cause disease. We searched specifically for PTMs because mutation of a modified amino acid almost always changes the chemistry of the side chain and can be interpreted as loss-of-function. We analyzed data from ClinVar for disease variants, Minimotif Miner and the C-terminome for PTMs, and RefSeq for protein sequences, yielding 20 such potential disease-causing variants. After additional screening, they include six with a previously reported PTM disruption mechanism and nine with new hypotheses for mutated minimotifs in C-termini that may cause disease. These mutations were generally for different genes, with four different PTM types and several different diseases. Our study helps to identify new molecular mechanisms for nine separate variants that cause disease, and this type of analysis could be extended as databases grow and to binding and trafficking motifs. We conclude that mutated motifs in C-termini are an infrequent cause of disease.
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Affiliation(s)
- Zachary T. FitzHugh
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV 89154, USA
- School of Life Sciences, University of Nevada, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA
| | - Martin R. Schiller
- Nevada Institute of Personalized Medicine, University of Nevada Las Vegas, 4505 S. Maryland Pkwy, Las Vegas, NV 89154, USA
- School of Life Sciences, University of Nevada, 4505 S. Maryland Parkway, Las Vegas, NV 89154, USA
- Heligenics Inc., 833 Las Vegas Blvd. North, Suite B, Las Vegas, NV 89101, USA
- Correspondence: ; Tel.: +1-702-895-5546; Fax: +1-702-895-5728
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12
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Krenn M, Sener M, Rath J, Zulehner G, Keritam O, Wagner M, Laccone F, Iglseder S, Marte S, Baumgartner M, Eisenkölbl A, Liechtenstein C, Rudnik S, Quasthoff S, Grinzinger S, Spenger J, Wortmann SB, Löscher WN, Zimprich F, Kellersmann A, Rappold M, Bernert G, Freilinger M, Cetin H. The clinical and molecular landscape of congenital myasthenic syndromes in Austria: a nationwide study. J Neurol 2023; 270:909-916. [PMID: 36308527 PMCID: PMC9886627 DOI: 10.1007/s00415-022-11440-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 10/18/2022] [Accepted: 10/19/2022] [Indexed: 02/03/2023]
Abstract
BACKGROUND Congenital myasthenic syndromes (CMS) are a heterogeneous group of disorders caused by genetic defects resulting in impaired neuromuscular transmission. Although effective treatments are available, CMS is probably underdiagnosed, and systematic clinico-genetic investigations are warranted. METHODS We used a nationwide approach to collect Austrian patients with genetically confirmed CMS. We provide a clinical and molecular characterization of this cohort and aimed to ascertain the current frequency of CMS in Austria. RESULTS Twenty-eight cases with genetically confirmed CMS were identified, corresponding to an overall prevalence of 3.1 per million (95% CI 2.0-4.3) in Austria. The most frequent genetic etiology was CHRNE (n = 13), accounting for 46.4% of the cohort. Within this subgroup, the variant c.1327del, p.(Glu443Lysfs*64) was detected in nine individuals. Moreover, causative variants were found in DOK7 (n = 4), RAPSN (n = 3), COLQ (n = 2), GMPPB (n = 2), CHAT (n = 1), COL13A1 (n = 1), MUSK (n = 1) and AGRN (n = 1). Clinical onset within the first year of life was reported in one half of the patients. Across all subtypes, the most common symptoms were ptosis (85.7%), lower limb (67.9%), upper limb (60.7%) and facial weakness (60.7%). The majority of patients (96.4%) received specific treatment, including acetylcholinesterase inhibitors in 20, adrenergic agonists in 11 and 3,4-diaminopyridine in nine patients. CONCLUSIONS Our study presents the first systematic characterization of individuals with CMS in Austria, providing prevalence estimates and genotype-phenotype correlations that may help to improve the diagnostic approach and patient management.
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Affiliation(s)
- Martin Krenn
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Merve Sener
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Jakob Rath
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Gudrun Zulehner
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Omar Keritam
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Matias Wagner
- Institute of Human Genetics, Technical University of Munich, Munich, Germany.,Institute for Neurogenomics, Helmholtz Center Munich, Munich, Germany
| | - Franco Laccone
- Institute of Medical Genetics, Medical University of Vienna, Vienna, Austria
| | - Stephan Iglseder
- Department of Neurology, Krankenhaus Barmherzige Brüder, Linz, Austria
| | | | - Manuela Baumgartner
- Department of Neuropaediatrics, Hospital Barmherzige Schwestern Linz, Linz, Austria
| | - Astrid Eisenkölbl
- Department of Paediatrics and Adolescent Medicine, Johannes Kepler University Linz, Linz, Austria
| | - Christian Liechtenstein
- Department of Paediatrics and Adolescent Medicine, Villach Regional Hospital, Villach, Austria
| | - Sabine Rudnik
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Stefan Quasthoff
- Department of Neurology, Medical University of Graz, Graz, Austria
| | - Susanne Grinzinger
- Department of Neurology, Salzburger Landeskliniken, Paracelsus Medical University, Salzburg, Austria
| | - Johannes Spenger
- University Children's Hospital, Paracelsus Medical University, Salzburg, Austria
| | - Saskia B Wortmann
- University Children's Hospital, Paracelsus Medical University, Salzburg, Austria.,Amalia Children's Hospital, Radboudumc, Nijmegen, The Netherlands
| | - Wolfgang N Löscher
- Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria
| | - Fritz Zimprich
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | | | - Mika Rappold
- Department of Pediatrics, Klinik Favoriten, Vienna, Austria
| | | | - Michael Freilinger
- Department of Pediatrics and Adolescent Medicine, Medical University of Vienna, Vienna, Austria
| | - Hakan Cetin
- Department of Neurology, Medical University of Vienna, Vienna, Austria.
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13
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GDP-Mannose Pyrophosphorylase B ( GMPPB)-Related Disorders. Genes (Basel) 2023; 14:genes14020372. [PMID: 36833299 PMCID: PMC9956253 DOI: 10.3390/genes14020372] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/29/2023] [Accepted: 01/30/2023] [Indexed: 02/04/2023] Open
Abstract
GDP-mannose pyrophosphorylase B (GMPPB) is a cytoplasmic protein that catalyzes the formation of GDP-mannose. Impaired GMPPB function reduces the amount of GDP-mannose available for the O-mannosylation of α-dystroglycan (α-DG) and ultimately leads to disruptions of the link between α-DG and extracellular proteins, hence dystroglycanopathy. GMPPB-related disorders are inherited in an autosomal recessive manner and caused by mutations in either a homozygous or compound heterozygous state. The clinical spectrum of GMPPB-related disorders spans from severe congenital muscular dystrophy (CMD) with brain and eye abnormalities to mild forms of limb-girdle muscular dystrophy (LGMD) to recurrent rhabdomyolysis without overt muscle weakness. GMPPB mutations can also lead to the defect of neuromuscular transmission and congenital myasthenic syndrome due to altered glycosylation of the acetylcholine receptor subunits and other synaptic proteins. Such impairment of neuromuscular transmission is a unique feature of GMPPB-related disorders among dystroglycanopathies. LGMD is the most common phenotypic presentation, characterized by predominant proximal weakness involving lower more than upper limbs. Facial, ocular, bulbar, and respiratory muscles are largely spared. Some patients demonstrate fluctuating fatigable weakness suggesting neuromuscular junction involvement. Patients with CMD phenotype often also have structural brain defects, intellectual disability, epilepsy, and ophthalmic abnormalities. Creatine kinase levels are typically elevated, ranging from 2 to >50 times the upper limit of normal. Involvement of the neuromuscular junction is demonstrated by the decrement in the compound muscle action potential amplitude on low-frequency (2-3 Hz) repetitive nerve stimulation in proximal muscles but not in facial muscles. Muscle biopsies typically show myopathic changes with variable degrees of reduced α-DG expression. Higher mobility of β-DG on Western blotting represents a specific feature of GMPPB-related disorders, distinguishing it from other α-dystroglycanopathies. Patients with clinical and electrophysiologic features of neuromuscular transmission defect can respond to acetylcholinesterase inhibitors alone or combined with 3,4 diaminopyridine or salbutamol.
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14
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Impact of Hypermannosylation on the Structure and Functionality of the ER and the Golgi Complex. Biomedicines 2023; 11:biomedicines11010146. [PMID: 36672654 PMCID: PMC9856158 DOI: 10.3390/biomedicines11010146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 12/20/2022] [Accepted: 12/29/2022] [Indexed: 01/10/2023] Open
Abstract
Proteins of the secretory pathway undergo glycosylation in the endoplasmic reticulum (ER) and the Golgi apparatus. Altered protein glycosylation can manifest in serious, sometimes fatal malfunctions. We recently showed that mutations in GDP-mannose pyrophosphorylase A (GMPPA) can cause a syndrome characterized by alacrima, achalasia, mental retardation, and myopathic alterations (AAMR syndrome). GMPPA acts as a feedback inhibitor of GDP-mannose pyrophosphorylase B (GMPPB), which provides GDP-mannose as a substrate for protein glycosylation. Loss of GMPPA thus enhances the incorporation of mannose into glycochains of various proteins, including α-dystroglycan (α-DG), a protein that links the extracellular matrix with the cytoskeleton. Here, we further characterized the consequences of loss of GMPPA for the secretory pathway. This includes a fragmentation of the Golgi apparatus, which comes along with a regulation of the abundance of several ER- and Golgi-resident proteins. We further show that the activity of the Golgi-associated endoprotease furin is reduced. Moreover, the fraction of α-DG, which is retained in the ER, is increased. Notably, WT cells cultured at a high mannose concentration display similar changes with increased retention of α-DG, altered structure of the Golgi apparatus, and a decrease in furin activity. In summary, our data underline the importance of a balanced mannose homeostasis for the secretory pathway.
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15
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Stojkovic T, Masingue M, Turmel H, Hezode-Arzel M, Béhin A, Leonard-Louis S, Bassez G, Bauché S, Blondy P, Richard P, Sternberg D, Eymard B, Fournier E, Villar-Quiles RN. Diagnostic yield of a practical electrodiagnostic protocol discriminating between different congenital myasthenic syndromes. Neuromuscul Disord 2022; 32:870-878. [PMID: 36522822 DOI: 10.1016/j.nmd.2022.10.001] [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: 06/13/2022] [Revised: 09/28/2022] [Accepted: 10/02/2022] [Indexed: 11/07/2022]
Abstract
Congenital myasthenic syndromes (CMS) are a group of heterogeneous diseases of the neuromuscular junction. We report electrodiagnostic testing (EDX) and genetic findings in a series of 120 CMS patients tested with a simple non-invasive EDX workup with surface recording of CMAPs and 3Hz repetitive nerve stimulation of accessory, radial and deep fibular nerves. Five ENMG phenotypes were retrieved based on the presence or not of R-CMAPs and the distribution pattern of decremental CMAP responses which significantly correlated with genetic findings (p <0.00001). R-CMAPs were found in all COLQ-mutated patients (CMS1A) and Slow Channel CMS (SCCMS) (CMS1B). CMS1A exhibited greater decrements in accessory nerve RNS than CMS1B. Patients without R-CMAPs were classified into CMS2A (DOK7-, MUSK-, GFPT1-, GMPPB-, TOR1AIP-mutated) when exhibiting predominant accessory nerve RNS decrements, CMS2B (CHRNE, CHRND, RAPSN) with predominant radial nerve RNS decrements, or CMS2C (AGRN) if there were predominant fibular decrements. Our algorithm may have a major impact on diagnostic and therapeutic monitoring in CMS patients, as well as for validation of the pathogenicity of genetic variants. It should also be part of the evaluation of unexplained muscle weakness or complex neuromuscular phenotypes.
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Affiliation(s)
- Tanya Stojkovic
- Reference Center for Neuromuscular Disorders (Nord/Est/Ile de France), Institute of Myology, Pitié-Salpêtrière Hospital, APHP, Pitié-Salpêtrière Hospital, Paris, France; Centre de Recherche en Myologie, Sorbonne Université-Inserm UMRS974, Paris, France
| | - Marion Masingue
- Reference Center for Neuromuscular Disorders (Nord/Est/Ile de France), Institute of Myology, Pitié-Salpêtrière Hospital, APHP, Pitié-Salpêtrière Hospital, Paris, France
| | - Helène Turmel
- Department of Neurophysiology, APHP, Pitié Salpetrière hospital, Paris, France
| | | | - Anthony Béhin
- Reference Center for Neuromuscular Disorders (Nord/Est/Ile de France), Institute of Myology, Pitié-Salpêtrière Hospital, APHP, Pitié-Salpêtrière Hospital, Paris, France
| | - Sarah Leonard-Louis
- Reference Center for Neuromuscular Disorders (Nord/Est/Ile de France), Institute of Myology, Pitié-Salpêtrière Hospital, APHP, Pitié-Salpêtrière Hospital, Paris, France
| | - Guillaume Bassez
- Reference Center for Neuromuscular Disorders (Nord/Est/Ile de France), Institute of Myology, Pitié-Salpêtrière Hospital, APHP, Pitié-Salpêtrière Hospital, Paris, France; Centre de Recherche en Myologie, Sorbonne Université-Inserm UMRS974, Paris, France
| | - Stéphanie Bauché
- Centre de Recherche en Myologie, Sorbonne Université-Inserm UMRS974, Paris, France
| | - Patricia Blondy
- National Reference Center for Muscle Channelopathies, APHP, Pitié Salpetrière hospital, Paris, France; Biochemistry Department, Center of Molecular and Cellular Genetics, APHP, Pitié Salpetrière hospital, Paris, France
| | - Pascale Richard
- Biochemistry Department, Center of Molecular and Cellular Genetics, APHP, Pitié Salpetrière hospital, Paris, France
| | - Damien Sternberg
- National Reference Center for Muscle Channelopathies, APHP, Pitié Salpetrière hospital, Paris, France; Biochemistry Department, Center of Molecular and Cellular Genetics, APHP, Pitié Salpetrière hospital, Paris, France
| | - Bruno Eymard
- Reference Center for Neuromuscular Disorders (Nord/Est/Ile de France), Institute of Myology, Pitié-Salpêtrière Hospital, APHP, Pitié-Salpêtrière Hospital, Paris, France
| | - Emmanuel Fournier
- Department of Neurophysiology, APHP, Pitié Salpetrière hospital, Paris, France; National Reference Center for Muscle Channelopathies, APHP, Pitié Salpetrière hospital, Paris, France; Department of Physiology, Sorbonne University, Faculté de médecine Pitié-Salpêtrière, Paris, France
| | - Rocío Nur Villar-Quiles
- Reference Center for Neuromuscular Disorders (Nord/Est/Ile de France), Institute of Myology, Pitié-Salpêtrière Hospital, APHP, Pitié-Salpêtrière Hospital, Paris, France; Centre de Recherche en Myologie, Sorbonne Université-Inserm UMRS974, Paris, France
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16
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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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17
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Dang K, Jiang S, Gao Y, Qian A. The role of protein glycosylation in muscle diseases. Mol Biol Rep 2022; 49:8037-8049. [DOI: 10.1007/s11033-022-07334-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 02/23/2022] [Accepted: 03/02/2022] [Indexed: 12/14/2022]
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18
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RNA sequencing and its applications in cancer and rare diseases. Mol Biol Rep 2022; 49:2325-2333. [PMID: 34988891 PMCID: PMC8731134 DOI: 10.1007/s11033-021-06963-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 11/16/2021] [Indexed: 12/19/2022]
Abstract
With the invention of RNA sequencing over a decade ago, diagnosis and identification of the gene-related diseases entered a new phase that enabled more accurate analysis of the diseases that are difficult to approach and analyze. RNA sequencing has availed in-depth study of transcriptomes in different species and provided better understanding of rare diseases and taxonomical classifications of various eukaryotic organisms. Development of single-cell, short-read, long-read and direct RNA sequencing using both blood and biopsy specimens of the organism together with recent advancement in computational analysis programs has made the medical professional’s ability in identifying the origin and cause of genetic disorders indispensable. Altogether, such advantages have evolved the treatment design since RNA sequencing can detect the resistant genes against the existing therapies and help medical professions to take a further step in improving methods of treatments towards higher effectiveness and less side effects. Therefore, it is of essence to all researchers and scientists to have deeper insight in all available methods of RNA sequencing while taking a step-in therapy design.
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19
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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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20
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Ramdas S, Beeson D. Congenital myasthenic syndromes: where do we go from here? Neuromuscul Disord 2021; 31:943-954. [PMID: 34736634 DOI: 10.1016/j.nmd.2021.07.400] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 07/22/2021] [Accepted: 07/27/2021] [Indexed: 11/27/2022]
Abstract
Congenital myasthenia syndromes are rare but often treatable conditions affecting neuromuscular transmission. They result from loss or impaired function of one of a number of proteins secondary to a genetic defect. An estimate of the prevalence in the UK gave 9.2 cases per million, however, this is likely an underestimate since the adoption of next generation sequencing for diagnosis away from specialist centres is enhancing the 'pick up' rate. Next generation sequencing has helped identify a series of novel genes that harbour mutations causative for congenital myasthenic syndrome that include not only genes that encode proteins specifically expressed at the neuromuscular junction but also those that are ubiquitously expressed. The list of genes harbouring disease-causing mutations for congenital myasthenic syndrome continues to expand and is now over 30, but with many of the newly identified genes it is increasingly being recognised that abnormal neuromuscular transmission is only one component of a multifaceted phenotype in which muscle, the central nervous system, and other organs may also be affected. Treatment can be tailored to the underlying molecular mechanism for impaired neuromuscular transmission but treating the more complex multifaceted disorders and will require development of new therapies.
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Affiliation(s)
- Sithara Ramdas
- MDUK Neuromuscular centre, Children's Hospital, John Radcliffe Hospital, Oxford, OX3 9DU, UK
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine, The John Radcliffe, Oxford OX3 9DS, UK.
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21
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Siddiqui S, Polavarapu K, Bardhan M, Preethish-Kumar V, Joshi A, Nashi S, Vengalil S, Raju S, Chawla T, Leena S, Mathur A, Nayak S, Mohan D, Shamim U, Prasad C, Lochmüller H, Faruq M, Nalini A. Distinct and Recognisable Muscle MRI Pattern in a Series of Adults Harbouring an Identical GMPPB Gene Mutation. J Neuromuscul Dis 2021; 9:95-109. [PMID: 34633329 DOI: 10.3233/jnd-200628] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND AND PURPOSE Mutations in the GMPPB gene affect glycosylation of α-dystroglycan, leading to varied clinical phenotypes. We attempted to delineate the muscle MR imaging spectrum of GMPPB-related Congenital Myasthenic syndrome (CMS) in a single-center cohort study. OBJECTIVE To identify the distinct patterns of muscle involvement in GMPPB gene mutations. METHODS We analyzed the muscle MR images of 7 genetically proven cases of GMPPB dystroglycanopathy belonging to three families and studied the potential qualitative imaging pattern to aid in clinico -radiological diagnosis in neuromuscular practice. All individuals underwent muscle MRI (T1, T2, STIR/PD Fat sat. sequences in 1.5 T machine) of the lower limbs. Qualitative assessment and scoring were done for muscle changes using Mercuri staging for fibro-fatty replacement on T1 sequence and Borsato score for myoedema on STIR sequence. RESULTS All patients were of South Indian origin and presented as slowly progressive childhood to adult-onset fatigable limb-girdle muscle weakness, elevated creatine kinase level, and positive decrement response in proximal muscles. Muscle biopsy revealed features of dystrophy. All patients demonstrated identical homozygous mutation c.1000G > A in the GMPPB gene. MRI demonstrated early and severe involvement of paraspinal muscles, gluteus minimus, and relatively less severe involvement of the short head of the biceps femoris. A distinct proximo-distal gradient of affliction was identified in the glutei, vasti, tibialis anterior and peronei. Also, a postero-anterior gradient was observed in the gracilis muscle. CONCLUSION Hitherto unreported, the distinctive MR imaging pattern described here, coupled with relatively slowly progressive symptoms of fatigable limb-girdle weakness, would facilitate an early diagnosis of the milder form of GMPPB- dystroglycanopathy associated with homozygous GMPPB gene mutation.
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Affiliation(s)
- Shahyan Siddiqui
- Department of Neuroimaging and Interventional radiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Kiran Polavarapu
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Mainak Bardhan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | | | - Aditi Joshi
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Saraswati Nashi
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Seena Vengalil
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Sanita Raju
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Tanushree Chawla
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Shingavi Leena
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Aradhana Mathur
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Sushmita Nayak
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Dhaarini Mohan
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - Uzma Shamim
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Chandrajit Prasad
- Department of Neuroimaging and Interventional radiology, National Institute of Mental Health and Neurosciences, Bengaluru, India
| | - 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
| | - Mohammed Faruq
- Genomics and Molecular Medicine, CSIR-Institute of Genomics and Integrative Biology, New Delhi, India
| | - Atchayaram Nalini
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, India
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22
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A founder mutation in the GMPPB gene [c.1000G > A (p.Asp334Asn)] causes a mild form of limb-girdle muscular dystrophy/congenital myasthenic syndrome (LGMD/CMS) in South Indian patients. Neurogenetics 2021; 22:271-285. [PMID: 34333724 DOI: 10.1007/s10048-021-00658-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 07/08/2021] [Indexed: 10/20/2022]
Abstract
Twelve patients from seven unrelated South Indian families with a limb-girdle muscular dystrophy-congenital myasthenic syndrome (LGMD/CMS) phenotype and recessive inheritance underwent deep clinical phenotyping, electrophysiological evaluation, muscle histopathology, and next-generation sequencing/Sanger sequencing-based identification of the genetic defect. Homozygosity mapping was performed using high-throughput genome-wide genotyping for mapping the mutation and to evaluate the founder effect. The age of disease onset among patients ranged from childhood to 40 years of age. The key clinical manifestations observed were progressive fatigable limb-girdle weakness, muscle hypertrophy/atrophy, and preferential weakness in a dystrophic pattern. The ages at last follow-up ranged from 30 to 64 years; nine were independently ambulant, two required assistance, and one was wheelchair-bound. Lower limb muscle MRI showed varying degrees of fat replacement in the glutei, hamstrings, anterior leg muscles, and medial gastrocnemius. All patients showed significant decrement on repetitive nerve stimulation (RNS). Muscle biopsy in 7 patients revealed varying degrees of dystrophic and neurogenic changes. Treatment with pyridostigmine and/or salbutamol resulted in variable improvement in 10 patients. Genetic analysis showed an identical homozygous GMPPB mutation c.1000G > A (p.Asp334Asn) in all affected patients. A region of homozygosity (6Mbp) was observed flanking the c.1000G > A change in carrier chromosomes. This study identifies c.1000G > A in GMPPB as a common founder mutation in an ethnic community of South Indian descent with milder yet variable degree of clinical presentation of GMPPB-associated LGMD-CMS.
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23
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Liu Z, Wang Y, Yang F, Yang Q, Mo X, Burstein E, Jia D, Cai XT, Tu Y. GMPPB-congenital disorders of glycosylation associate with decreased enzymatic activity of GMPPB. MOLECULAR BIOMEDICINE 2021; 2:13. [PMID: 35006422 PMCID: PMC8607393 DOI: 10.1186/s43556-021-00027-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 01/12/2021] [Indexed: 02/08/2023] Open
Abstract
The congenital disorders of glycosylation (CDG) are a family of metabolic diseases in which glycosylation of proteins or lipids is deficient. GDP-mannose pyrophosphorylase B (GMPPB) mutations lead to CDG, characterized by neurological and muscular defects. However, the genotype-phenotype correlation remains elusive, limiting our understanding of the underlying mechanism and development of therapeutic strategy. Here, we report a case of an individual presenting congenital muscular dystrophy with cerebellar involvement, who presents two heterozygous GMPPB mutations (V111G and G214S). The V111G mutation significantly decreases GMPPB’s enzymatic activity. By measuring enzymatic activities of 17 reported GMPPB mutants identified in patients diagnosed with GMPPB-CDG, we discover that all tested GMPPB variants exhibit significantly decreased enzymatic activity. Using a zebrafish model, we find that Gmppb is required for neuronal and muscle development, and further demonstrate that enzymatic activity of GMPPB mutants correlates with muscular and neuronal phenotypes in zebrafish. Taken together, our findings discover the importance of GMPPB enzymatic activity for the pathogenesis of GMPPB-CDG, and shed light for the development of additional indicators and therapeutic strategy.
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Affiliation(s)
- Zhe Liu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Yan Wang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Fan Yang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Qin Yang
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, 610041, China
| | - Xianming Mo
- Department of Pediatric Surgery and Laboratory of Stem Cell Biology, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Ezra Burstein
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
| | - Xiao-Tang Cai
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
| | - Yingfeng Tu
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Paediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, 610041, China.
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24
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Franzka P, Henze H, Jung MJ, Schüler SC, Mittag S, Biskup K, Liebmann L, Kentache T, Morales J, Martínez B, Katona I, Herrmann T, Huebner AK, Hennings JC, Groth S, Gresing L, Horstkorte R, Marquardt T, Weis J, Kaether C, Mutchinick OM, Ori A, Huber O, Blanchard V, von Maltzahn J, Hübner CA. GMPPA defects cause a neuromuscular disorder with α-dystroglycan hyperglycosylation. J Clin Invest 2021; 131:139076. [PMID: 33755596 DOI: 10.1172/jci139076] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
GDP-mannose-pyrophosphorylase-B (GMPPB) facilitates the generation of GDP-mannose, a sugar donor required for glycosylation. GMPPB defects cause muscle disease due to hypoglycosylation of α-dystroglycan (α-DG). Alpha-DG is part of a protein complex, which links the extracellular matrix with the cytoskeleton, thus stabilizing myofibers. Mutations of the catalytically inactive homolog GMPPA cause alacrima, achalasia, and mental retardation syndrome (AAMR syndrome), which also involves muscle weakness. Here, we showed that Gmppa-KO mice recapitulated cognitive and motor deficits. As structural correlates, we found cortical layering defects, progressive neuron loss, and myopathic alterations. Increased GDP-mannose levels in skeletal muscle and in vitro assays identified GMPPA as an allosteric feedback inhibitor of GMPPB. Thus, its disruption enhanced mannose incorporation into glycoproteins, including α-DG in mice and humans. This increased α-DG turnover and thereby lowered α-DG abundance. In mice, dietary mannose restriction beginning after weaning corrected α-DG hyperglycosylation and abundance, normalized skeletal muscle morphology, and prevented neuron degeneration and the development of motor deficits. Cortical layering and cognitive performance, however, were not improved. We thus identified GMPPA defects as the first congenital disorder of glycosylation characterized by α-DG hyperglycosylation, to our knowledge, and we have unraveled underlying disease mechanisms and identified potential dietary treatment options.
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Affiliation(s)
- Patricia Franzka
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Henriette Henze
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | - M Juliane Jung
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | | | - Sonnhild Mittag
- Department of Biochemistry II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Karina Biskup
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany
| | - Lutz Liebmann
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Takfarinas Kentache
- Welbio and de Duve Institute, Université Catholique de Louvain, Brussels, Belgium
| | - José Morales
- Department of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Braulio Martínez
- Department of Pathology, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Istvan Katona
- Institut für Neuropathologie, Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Tanja Herrmann
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Antje-Kathrin Huebner
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - J Christopher Hennings
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Susann Groth
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | - Lennart Gresing
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Rüdiger Horstkorte
- Institut für Physiologische Chemie, Martin-Luther-Universität Halle-Wittenberg, Halle, Germany
| | - Thorsten Marquardt
- University Hospital Muenster, Department of Pediatrics, Muenster, Germany
| | - Joachim Weis
- Institut für Neuropathologie, Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | | | - Osvaldo M Mutchinick
- Department of Genetics, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
| | - Alessandro Ori
- Leibniz-Institute on Aging - Fritz-Lipmann-Institute, Jena, Germany
| | - Otmar Huber
- Department of Biochemistry II, University Hospital Jena, Friedrich Schiller University, Jena, Germany
| | - Véronique Blanchard
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Berlin, Germany
| | | | - Christian A Hübner
- Institute of Human Genetics, University Hospital Jena, Friedrich Schiller University, Jena, Germany
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25
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Papazoglu GM, Cubilla M, Pereyra M, de Kremer RD, Pérez B, Sturiale L, Asteggiano CG. Mass spectrometry glycophenotype characterization of ALG2-CDG in Argentinean patients with a new genetic variant in homozygosis. Glycoconj J 2021; 38:191-200. [PMID: 33644825 DOI: 10.1007/s10719-021-09976-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 01/29/2021] [Accepted: 02/04/2021] [Indexed: 12/16/2022]
Abstract
Human ALG2 encodes an α 1,3mannosyltransferase that catalyzes the first steps in the synthesis of N-glycans in the endoplasmic reticulum. Variants in ALG2cause a congenital disorder of glycosylation (CDG) known as ALG2-CDG. Up to date, nine ALG2-CDG patients have been reported worldwide. ALG2-CDG is a rare autosomal recessive inherited disorder characterized by neurological involvement, convulsive syndrome of unknown origin, axial hypotonia, and mental and motor regression. In this study, we used MALDI-TOF MS to define both total serum protein and transferrin (Tf) N-glycan phenotypes in three ALG2-CDG patients carrying a c.752G > T, p.Arg251Leu ALG2 missense variant in homozygous state, as determined by exome sequencing. Comparing it to control samples, we have observed Tf under-occupancy of glycosylation site(s) typical of a defective N-glycan assembly and the occurrence of oligomannose and hybrid type N-glycans. Moreover, we have observed a slight oligomannose accumulation in total serum glyco-profiles. The increased heterogeneity of serum N-glycome in the studied patients suggests a marginal disarrangement of the glycan processing in ALG2-CDG. Previous studies reported on slightly increased concentrations of abnormal serum N-glycans in CDG-I due to defects in the mannosylation steps of dolichol-linked oligosaccharide biosynthesis. This preliminary work aims at considering serum N-glycan accumulation of high mannosylated glycoforms, such as oligomannose and hybrid type N-glycans, as potential diagnostic signals for ALG2-CDG patients.
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Affiliation(s)
- Gabriela Magali Papazoglu
- Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Santísima Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, X5014AKN, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - Marisa Cubilla
- Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Santísima Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, X5014AKN, Córdoba, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina
| | - Marcela Pereyra
- Servicio de Crecimiento y Desarrollo, Hospital Pediátrico HumbertoNotti, Mendoza, Argentina
| | - Raquel Dodelson de Kremer
- Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Santísima Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, X5014AKN, Córdoba, Argentina
| | - Belén Pérez
- Centro de Diagnóstico de Enfermedades Moleculares (CEDEM), Centro de Biología Molecular Severo Ochoa CSIC-UAM, CIBERER, IdiPAZ, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luisa Sturiale
- CNR, Institute for Polymers, Composites and Biomaterials, IPCB, Catania, Italy
| | - Carla Gabriela Asteggiano
- Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Santísima Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, X5014AKN, Córdoba, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Córdoba, Argentina.
- Facultad de Ciencias de la Salud, Carrera Medicina, Universidad Católica de Córdoba (UCC), Jacinto Ríos 571 (X5004ASK), B° General Paz, Córdoba, Argentina.
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26
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Rodríguez Cruz PM, Cossins J, Beeson D, Vincent A. The Neuromuscular Junction in Health and Disease: Molecular Mechanisms Governing Synaptic Formation and Homeostasis. Front Mol Neurosci 2020; 13:610964. [PMID: 33343299 PMCID: PMC7744297 DOI: 10.3389/fnmol.2020.610964] [Citation(s) in RCA: 87] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/30/2020] [Indexed: 12/28/2022] Open
Abstract
The neuromuscular junction (NMJ) is a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber that are responsible for converting electrical impulses generated by the motor neuron into electrical activity in the muscle fibers. On arrival of the motor nerve action potential, calcium enters the presynaptic terminal, which leads to the release of the neurotransmitter acetylcholine (ACh). ACh crosses the synaptic gap and binds to ACh receptors (AChRs) tightly clustered on the surface of the muscle fiber; this leads to the endplate potential which initiates the muscle action potential that results in muscle contraction. This is a simplified version of the events in neuromuscular transmission that take place within milliseconds, and are dependent on a tiny but highly structured NMJ. Much of this review is devoted to describing in more detail the development, maturation, maintenance and regeneration of the NMJ, but first we describe briefly the most important molecules involved and the conditions that affect their numbers and function. Most important clinically worldwide, are myasthenia gravis (MG), the Lambert-Eaton myasthenic syndrome (LEMS) and congenital myasthenic syndromes (CMS), each of which causes specific molecular defects. In addition, we mention the neurotoxins from bacteria, snakes and many other species that interfere with neuromuscular transmission and cause potentially fatal diseases, but have also provided useful probes for investigating neuromuscular transmission. There are also changes in NMJ structure and function in motor neuron disease, spinal muscle atrophy and sarcopenia that are likely to be secondary but might provide treatment targets. The NMJ is one of the best studied and most disease-prone synapses in the nervous system and it is amenable to in vivo and ex vivo investigation and to systemic therapies that can help restore normal function.
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Affiliation(s)
- Pedro M. Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Judith Cossins
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
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27
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Silva-Rojas R, Laporte J, Böhm J. STIM1/ ORAI1 Loss-of-Function and Gain-of-Function Mutations Inversely Impact on SOCE and Calcium Homeostasis and Cause Multi-Systemic Mirror Diseases. Front Physiol 2020; 11:604941. [PMID: 33250786 PMCID: PMC7672041 DOI: 10.3389/fphys.2020.604941] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 10/15/2020] [Indexed: 12/19/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is a ubiquitous and essential mechanism regulating Ca2+ homeostasis in all tissues, and controls a wide range of cellular functions including keratinocyte differentiation, osteoblastogenesis and osteoclastogenesis, T cell proliferation, platelet activation, and muscle contraction. The main SOCE actors are STIM1 and ORAI1. Depletion of the reticular Ca2+ stores induces oligomerization of the luminal Ca2+ sensor STIM1, and the oligomers activate the plasma membrane Ca2+ channel ORAI1 to trigger extracellular Ca2+ entry. Mutations in STIM1 and ORAI1 result in abnormal SOCE and lead to multi-systemic disorders. Recessive loss-of-function mutations are associated with CRAC (Ca2+ release-activated Ca2+) channelopathy, involving immunodeficiency and autoimmunity, muscular hypotonia, ectodermal dysplasia, and mydriasis. In contrast, dominant STIM1 and ORAI1 gain-of-function mutations give rise to tubular aggregate myopathy and Stormorken syndrome (TAM/STRMK), forming a clinical spectrum encompassing muscle weakness, thrombocytopenia, ichthyosis, hyposplenism, short stature, and miosis. Functional studies on patient-derived cells revealed that CRAC channelopathy mutations impair SOCE and extracellular Ca2+ influx, while TAM/STRMK mutations induce excessive Ca2+ entry through SOCE over-activation. In accordance with the opposite pathomechanisms underlying both disorders, CRAC channelopathy and TAM/STRMK patients show mirror phenotypes at the clinical and molecular levels, and the respective animal models recapitulate the skin, bones, immune system, platelet, and muscle anomalies. Here we review and compare the clinical presentations of CRAC channelopathy and TAM/STRMK patients and the histological and molecular findings obtained on human samples and murine models to highlight the mirror phenotypes in different tissues, and to point out potentially undiagnosed anomalies in patients, which may be relevant for disease management and prospective therapeutic approaches.
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Affiliation(s)
- Roberto Silva-Rojas
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm U1258, CNRS UMR 7104, Université de Strasbourg, Illkirch, France
| | - Jocelyn Laporte
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm U1258, CNRS UMR 7104, Université de Strasbourg, Illkirch, France
| | - Johann Böhm
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Inserm U1258, CNRS UMR 7104, Université de Strasbourg, Illkirch, France
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28
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Cossins J, Webster R, Maxwell S, Rodríguez Cruz PM, Knight R, Llewelyn JG, Shin JY, Palace J, Beeson D. Congenital myasthenic syndrome due to a TOR1AIP1 mutation: a new disease pathway for impaired synaptic transmission. Brain Commun 2020; 2:fcaa174. [PMID: 33215087 PMCID: PMC7660151 DOI: 10.1093/braincomms/fcaa174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/24/2020] [Accepted: 08/12/2020] [Indexed: 02/06/2023] Open
Abstract
Congenital myasthenic syndromes are inherited disorders characterized by fatiguable muscle weakness resulting from impaired signal transmission at the neuromuscular junction. Causative mutations have been identified in genes that can affect the synaptic function or structure. We identified a homozygous frameshift deletion c.127delC, p. Pro43fs in TOR1AIP1 in two siblings with limb-girdle weakness and impaired transmission at the neuromuscular synapse. TOR1AIP1 encodes the inner nuclear membrane protein lamin-associated protein 1. On muscle biopsy from the index case, lamin-associated protein 1 was absent from myonuclei. A mouse model with lamin-associated protein 1 conditionally knocked out in striated muscle was used to analyse the role of lamin-associated protein 1 in synaptic dysfunction. Model mice develop fatiguable muscle weakness as demonstrated by using an inverted screen hang test. Electromyography on the mice revealed a decrement on repetitive nerve stimulation. Ex vivo analysis of hemi-diaphragm preparations showed both miniature and evoked end-plate potential half-widths were prolonged which was associated with upregulation of the foetal acetylcholine receptor γ subunit. Neuromuscular junctions on extensor digitorum longus muscles were enlarged and fragmented, and the number of subsynaptic nuclei was significantly increased. Following these findings, electromyography was performed on cases of other nuclear envelopathies caused by mutations in LaminA/C or emerin, but decrement on repetitive nerve stimulation or other indications of defective neuromuscular transmission were not seen. Thus, this report highlights the first nuclear membrane protein in which defective function can lead to impaired synaptic transmission.
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Affiliation(s)
- Judith Cossins
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Richard Webster
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Susan Maxwell
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Pedro M Rodríguez Cruz
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Ravi Knight
- Department of Clinical Neurology, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - John Gareth Llewelyn
- Neurology Department, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK
| | - Ji-Yeon Shin
- Department of Medicine, Columbia University Medical Centre, New York, NY 10032, USA
| | - Jacqueline Palace
- Department of Clinical Neurology, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
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29
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Ravenscroft G, Clayton JS, Faiz F, Sivadorai P, Milnes D, Cincotta R, Moon P, Kamien B, Edwards M, Delatycki M, Lamont PJ, Chan SH, Colley A, Ma A, Collins F, Hennington L, Zhao T, McGillivray G, Ghedia S, Chao K, O'Donnell-Luria A, Laing NG, Davis MR. Neurogenetic fetal akinesia and arthrogryposis: genetics, expanding genotype-phenotypes and functional genomics. J Med Genet 2020; 58:609-618. [PMID: 33060286 DOI: 10.1136/jmedgenet-2020-106901] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 05/16/2020] [Accepted: 07/05/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND Fetal akinesia and arthrogryposis are clinically and genetically heterogeneous and have traditionally been refractive to genetic diagnosis. The widespread availability of affordable genome-wide sequencing has facilitated accurate genetic diagnosis and gene discovery in these conditions. METHODS We performed next generation sequencing (NGS) in 190 probands with a diagnosis of arthrogryposis multiplex congenita, distal arthrogryposis, fetal akinesia deformation sequence or multiple pterygium syndrome. This sequencing was a combination of bespoke neurogenetic disease gene panels and whole exome sequencing. Only class 4 and 5 variants were reported, except for two cases where the identified variants of unknown significance (VUS) are most likely to be causative for the observed phenotype. Co-segregation studies and confirmation of variants identified by NGS were performed where possible. Functional genomics was performed as required. RESULTS Of the 190 probands, 81 received an accurate genetic diagnosis. All except two of these cases harboured class 4 and/or 5 variants based on the American College of Medical Genetics and Genomics guidelines. We identified phenotypic expansions associated with CACNA1S, CHRNB1, GMPPB and STAC3. We describe a total of 50 novel variants, including a novel missense variant in the recently identified gene for arthrogryposis with brain malformations-SMPD4. CONCLUSIONS Comprehensive gene panels give a diagnosis for a substantial proportion (42%) of fetal akinesia and arthrogryposis cases, even in an unselected cohort. Recently identified genes account for a relatively large proportion, 32%, of the diagnoses. Diagnostic-research collaboration was critical to the diagnosis and variant interpretation in many cases, facilitated genotype-phenotype expansions and reclassified VUS through functional genomics.
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Affiliation(s)
- Gina Ravenscroft
- Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia .,Faculty of Health and Medical Sciences, University of Western Australia, Nedlands, Western Australia, Australia
| | - Joshua S Clayton
- Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia.,Faculty of Health and Medical Sciences, University of Western Australia, Nedlands, Western Australia, Australia
| | - Fathimath Faiz
- PathWest Diagnostic Genomics, Nedlands, Western Australia, Australia
| | - Padma Sivadorai
- PathWest Diagnostic Genomics, Nedlands, Western Australia, Australia
| | - Di Milnes
- Genetic Health Queensland, Royal Brisbane and Women's Hospital, Herston, Queensland, Australia
| | - Rob Cincotta
- Maternal and Fetal Medicine, Mater Mothers' Hospital, Brisbane, Queensland, Australia
| | - Phillip Moon
- Department of Obstetrics, Redland Hospital, Cleveland, Queensland, Australia
| | - Ben Kamien
- Genetic Services WA, Women and Newborn Heath Service, Subiaco, Western Australia, Australia.,Hunter Genetics, Hunter New England Health, New Lambton, New South Wales, Australia
| | - Matthew Edwards
- Hunter Genetics, Hunter New England Health, New Lambton, New South Wales, Australia
| | - Martin Delatycki
- Victorian Clinical Genetics Service, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Phillipa J Lamont
- Neurology, Royal Perth Hospital, Perth, Western Australia, Australia
| | - Sophelia Hs Chan
- Paediatric Neurology Division, Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, Hong Kong
| | - Alison Colley
- Clinical Genetics Services SWSLHD, Liverpool Hospital, Liverpool, New South Wales, Australia
| | - Alan Ma
- Department of Clinical Genetics, Children's Hospital Westmead, Sydney, New South Wales, Australia
| | - Felicity Collins
- Clinical Genetics Department, Western Sydney Genetics Program, Children's Hospitalat Westmead, Westmead, New South Wales, Australia
| | - Lucinda Hennington
- Mercy Health, Mercy Hospital for Women, Heidelberg, Victoria, Australia.,Austin Health, Melbourne, Victoria, Australia.,Alfred Health, Melbourne, Victoria, Australia
| | - Teresa Zhao
- Victorian Clinical Genetics Service, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - George McGillivray
- Victorian Clinical Genetics Service, Murdoch Children's Research Institute, Melbourne, Victoria, Australia
| | - Sondhya Ghedia
- Department of Clinical Genetics, Royal North Shore Hospital, Sydney, New South Wales, Australia
| | - Katherine Chao
- Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts, USA
| | - Anne O'Donnell-Luria
- Center for Mendelian Genomics, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts, USA
| | - Nigel G Laing
- Harry Perkins Institute of Medical Research, Perth, Western Australia, Australia.,Faculty of Health and Medical Sciences, University of Western Australia, Nedlands, Western Australia, Australia.,PathWest Diagnostic Genomics, Nedlands, Western Australia, Australia
| | - Mark R Davis
- PathWest Diagnostic Genomics, Nedlands, Western Australia, Australia
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30
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Ondruskova N, Cechova A, Hansikova H, Honzik T, Jaeken J. Congenital disorders of glycosylation: Still "hot" in 2020. Biochim Biophys Acta Gen Subj 2020; 1865:129751. [PMID: 32991969 DOI: 10.1016/j.bbagen.2020.129751] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/12/2020] [Accepted: 08/27/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Congenital disorders of glycosylation (CDG) are inherited metabolic diseases caused by defects in the genes important for the process of protein and lipid glycosylation. With the ever growing number of the known subtypes and discoveries regarding the disease mechanisms and therapy development, it remains a very active field of study. SCOPE OF REVIEW This review brings an update on the CDG-related research since 2017, describing the novel gene defects, pathobiomechanisms, biomarkers and the patients' phenotypes. We also summarize the clinical guidelines for the most prevalent disorders and the current therapeutical options for the treatable CDG. MAJOR CONCLUSIONS In the majority of the 23 new CDG, neurological involvement is associated with other organ disease. Increasingly, different aspects of cellular metabolism (e.g., autophagy) are found to be perturbed in multiple CDG. GENERAL SIGNIFICANCE This work highlights the recent trends in the CDG field and comprehensively overviews the up-to-date clinical recommendations.
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Affiliation(s)
- Nina Ondruskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Anna Cechova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Hana Hansikova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Tomas Honzik
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
| | - Jaak Jaeken
- Department of Paediatrics and Centre for Metabolic Diseases, KU Leuven and University Hospital Leuven, Leuven, Belgium.
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31
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Bobadilla-Quesada EJ, Natera-de Benito D, Carrera-García L, Ortez C, Exposito-Escudero J, Jimenez-Mallebrera C, Jou C, Codina A, Corbera J, Moya O, Saez V, Gonzalez-Quereda L, Gallano P, Colomer J, Cuadras D, Medina J, Yoldi ME, Nascimento A. Early and long-term effect of the treatment with pyridostigmine in patients with GMPPB-related congenital myasthenic syndrome. Neuromuscul Disord 2020; 30:719-726. [PMID: 32819792 DOI: 10.1016/j.nmd.2020.07.009] [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: 04/15/2020] [Revised: 07/16/2020] [Accepted: 07/20/2020] [Indexed: 11/28/2022]
Abstract
GMPPB mutations cause congenital myasthenic syndromes (CMS) overlapping with muscular dystrophy. Treatment with pyridostigmine has been reported to be effective in those patients. Nevertheless, results of functional motor assessments to determine its precise impact on the short and long term were not available. We describe the response to treatment with pyridostigmine in three siblings with GMPPB-related CMS using functional motor scales performed regularly over a period of 40 months. The beneficial effect of the treatment was outstanding within the first hours, with all the scales showing a dramatic increase in only two days. This remarkable improvement remained steady during 12 months but a moderate decrease was subsequently detected in two of the three patients. Despite this decline in the scores of the scales at the end of follow up, the functional motor status of the patients was still significantly better than it was before starting treatment. The introduction of pyridostigmine at an early age of the disease in one of the patients, before the onset of scoliosis, may have had a protective effect on it.
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Affiliation(s)
- Edna Julieth Bobadilla-Quesada
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
| | - Daniel Natera-de Benito
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain.
| | - Laura Carrera-García
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
| | - Carlos Ortez
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
| | - Jessica Exposito-Escudero
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
| | - Cecilia Jimenez-Mallebrera
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
| | - Cristina Jou
- Department of Pathology, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Anna Codina
- Department of Pathology, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Joan Corbera
- Department of Pathology, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Obdulia Moya
- Rehabilitation and Physical Unit Department, Hospital Sant Joan de Deu, Barcelona, Spain
| | - Veronica Saez
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
| | - Lidia Gonzalez-Quereda
- Department of Genetics, Hospital de la Santa Creu i Sant Pau and CIBERER U705, Barcelona, Spain
| | - Pia Gallano
- Department of Genetics, Hospital de la Santa Creu i Sant Pau and CIBERER U705, Barcelona, Spain
| | - Jaume Colomer
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
| | - Daniel Cuadras
- Statistics Department, Fundació Sant Joan de Déu, Barcelona, Spain
| | - Julita Medina
- Rehabilitation and Physical Unit Department, Hospital Sant Joan de Deu, Barcelona, Spain
| | - María Eugenia Yoldi
- Pediatric Neurology Unit, Department of Pediatrics, Navarra Health Service, Navarrabiomed, Pamplona, Spain
| | - Andrés Nascimento
- Neuromuscular Unit, Neuropaediatrics Department, Institut de Recerca Hospital Sant Joan de Déu and CIBERER U703, Barcelona, Spain
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32
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The congenital myasthenic syndromes: expanding genetic and phenotypic spectrums and refining treatment strategies. Curr Opin Neurol 2020; 32:696-703. [PMID: 31361628 PMCID: PMC6735524 DOI: 10.1097/wco.0000000000000736] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Congenital myasthenic syndromes (CMS) are a group of heterogeneous inherited disorders caused by mutations in genes encoding proteins whose function is essential for the integrity of neuromuscular transmission. This review updates the reader on the expanding phenotypic spectrum and suggested improved treatment strategies.
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33
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Troha Gergeli A, Neubauer D, Golli T, Butenko T, Loboda T, Maver A, Osredkar D. Prevalence and genetic subtypes of congenital myasthenic syndromes in the pediatric population of Slovenia. Eur J Paediatr Neurol 2020; 26:34-38. [PMID: 32070632 DOI: 10.1016/j.ejpn.2020.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 01/08/2020] [Accepted: 02/07/2020] [Indexed: 12/15/2022]
Abstract
AIM Congenital myasthenic syndromes (CMS) are rare, genetically and phenotypically diverse disorders of neuromuscular transmission. Data on prevalence among children are scarce. Whole exome sequencing facilitated discovery of novel CMS mutations and enabled targeted treatment. Our aim was to identify the prevalence, genetic subtypes and clinical characteristics of CMS in pediatric population of Slovenia. METHODS In this observational, national, cross-sectional study, medical records were retrospectively reviewed. Children with genetically confirmed CMS, referred over a 19 - year period (2000-2018) to the University Medical Centre, Ljubljana, Slovenia, were included in the study. Genetic and phenotypic characteristics were collected and prevalence of CMS in children was calculated. RESULTS Eight children with a confirmed genetic mutation in 5 different genes (CHRNE, CHRND, RAPSN, CHAT, MUSK) causative of the CMS were identified. Calculated prevalence of genetically confirmed CMS was 22.2 cases per 1.000.000 children at the end of 2018. INTERPRETATION The prevalence of genetically confirmed CMS in Slovenian children at the end of 2018 exceeds previously reported prevalence by more than two-fold, which suggests that prevalence in the literature is likely to be underestimated. Two extremely rarely detected mutations in MUSK and CHRND gene were detected and patient's clinical descriptions add important information on genotype-phenotype correlation.
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Affiliation(s)
- Anja Troha Gergeli
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia
| | - David Neubauer
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia
| | - Tanja Golli
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia
| | - Tita Butenko
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia
| | - Tanja Loboda
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia
| | - Aleš Maver
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Slovenia
| | - Damjan Osredkar
- Department of Child, Adolescent and Developmental Neurology, University Children's Hospital, University Medical Centre Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Slovenia.
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34
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Sun L, Shen D, Xiong T, Zhou Z, Lu X, Cui F. Limb-girdle muscular dystrophy due to GMPPB mutations: A case report and comprehensive literature review. Bosn J Basic Med Sci 2020; 20:275-280. [PMID: 30684953 PMCID: PMC7202191 DOI: 10.17305/bjbms.2019.3992] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 12/19/2018] [Indexed: 11/16/2022] Open
Abstract
Mutations in the guanosine diphosphate mannose (GDP-mannose) pyrophosphorylase B (GMPPB) gene are rare. To date, 72 cases with GMPPB gene mutations have been reported. Herein, we reported a case of a 29-year-old Chinese male presenting with limb-girdle muscular dystrophy (LGMD) who was found to have two heterozygous GMPPB mutations. The patient had a progressive limb weakness for 19 years. His parents and elder brother were healthy. On examination he had a waddling gait and absent tendon reflexes in all four limbs. Electromyography showed myogenic damage. Muscle magnetic resonance imaging (MRI) showed fatty degeneration in the bilateral medial thigh muscles. High-throughput gene panel sequencing revealed that the patient carried compound heterozygous mutations in the GMPPB gene, c.553C>T (p.R185C, maternal inheritance) and c.346C>T (p.P116S, paternal inheritance). This case provides additional information regarding the phenotypic spectrum of GMPPB mutations in the Chinese population.
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Affiliation(s)
- LiuQing Sun
- Department of Neurology, Hainan Branch of Chinese PLA General Hospital, Sanya, Hainan Province, China
| | - DingGuo Shen
- Department of Neurology, Xi'an Gaoxin Hospital, Xi'an, Shanxi Province, China
| | - Ting Xiong
- Department of Neurology, Xi'an Gaoxin Hospital, Xi'an, Shanxi Province, China
| | - Zhibin Zhou
- Department of Neurology, Hainan Branch of Chinese PLA General Hospital, Sanya, Hainan Province, China
| | - Xianghui Lu
- Department of Neurology, Hainan Branch of Chinese PLA General Hospital, Sanya, Hainan Province, China
| | - Fang Cui
- Department of Neurology, Hainan Branch of Chinese PLA General Hospital, Sanya, Hainan Province, China
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35
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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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36
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Gonzalez-Perez P, Smith C, Sebetka WL, Gedlinske A, Perlman S, Mathews KD. Clinical and electrophysiological evaluation of myasthenic features in an alpha-dystroglycanopathy cohort (FKRP-predominant). Neuromuscul Disord 2020; 30:213-218. [PMID: 32115343 PMCID: PMC7778731 DOI: 10.1016/j.nmd.2020.01.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 01/16/2020] [Accepted: 01/21/2020] [Indexed: 01/29/2023]
Abstract
A postsynaptic dysfunction of the neuromuscular junction has been reported in patients with alpha-dystroglycanopathy associated with mutations in guanosine diphosphate (GDP)-mannose pyrophosphorylase B gene (GMPPB), some of whom benefit from symptomatic treatment. In this study, we determine the frequency of myasthenic and fatigue symptoms and neuromuscular junction transmission defects in a fukutin-related protein (FKRP)-predominant alpha-dystroglycanopathy cohort. Thirty-one patients with alpha-dystroglycanopathies due to mutations in FKRP (n = 25), GMPPB (n = 4), POMGNT1 (n = 1), and POMT2 (n = 1) completed a six-question modified questionnaire for myasthenic symptoms and the PROMIS Short Form v1.0-Fatigue 8a survey, and they underwent 3 Hz repetitive nerve stimulation of spinal accessory nerve-trapezius and radial nerve-anconeus pairs. Results showed that fatigue with activity was common; 63% of the cohort reported fatigue with chewing. A defective postsynaptic neuromuscular junction transmission was not identified in any of the patients carrying FKRP mutations but only in one mildly affected patient with GMPPB mutations (c.79 G>C, p.D27H and c.402+1G>A, splice site variant). We conclude that symptoms of fatigue with activity did not predict abnormal neuromuscular junction transmission on electrodiagnostic studies in this cohort and that, unlike GMPPB subgroup, a defective neuromuscular junction transmission does not appear to be present in patients with FKRP-associated muscular dystrophies.
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Affiliation(s)
- Paloma Gonzalez-Perez
- Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, United States.
| | - Cheryl Smith
- Department of Neurology, West Virginia University Hospitals, Morgantown, WV 26506, United States
| | - Wendy L Sebetka
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States
| | - Amber Gedlinske
- Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States
| | - Seth Perlman
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States; Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States
| | - Katherine D Mathews
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States; Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, United States
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Abstract
The peripheral nervous system (PNS) is composed of motor neurons, nerve roots, plexuses, peripheral nerves (motor, sensory and autonomic), neuromuscular junction, and skeletal muscles. Disorders of the PNS in neonates most frequently cause weakness, hypotonia, and contractures, which may be generalized or focal. Since these findings may also occur with brain and spinal cord lesions, key features of the history and neurologic exam, together with diagnostic testing, are helpful in reaching a diagnosis. This review covers the diagnostic approach to PNS disorders in the neonate and includes a discussion of representative diseases of the motor neuron, brachial plexus, peripheral nerves, neuromuscular junction, and muscles. The importance of reaching a precise genetic diagnosis is highlighted with a discussion of current and emerging treatments for neonatal PNS diseases, particularly spinal muscular atrophy.
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Affiliation(s)
- Alex J Fay
- Department of Neurology, University of California, San Francisco, San Francisco, CA.
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Nicolau S, Kao JC, Liewluck T. Trouble at the junction: When myopathy and myasthenia overlap. Muscle Nerve 2019; 60:648-657. [PMID: 31449669 DOI: 10.1002/mus.26676] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 08/18/2019] [Accepted: 08/20/2019] [Indexed: 12/22/2022]
Abstract
Although myopathies and neuromuscular junction disorders are typically distinct, their coexistence has been reported in several inherited and acquired conditions. Affected individuals have variable clinical phenotypes but typically display both a decrement on repetitive nerve stimulation and myopathic findings on muscle biopsy. Inherited causes include myopathies related to mutations in BIN1, DES, DNM2, GMPPB, MTM1, or PLEC and congenital myasthenic syndromes due to mutations in ALG2, ALG14, COL13A1, DOK7, DPAGT1, or GFPT1. Additionally, a decrement due to muscle fiber inexcitability is observed in certain myotonic disorders. The identification of a defect of neuromuscular transmission in an inherited myopathy may assist in establishing a molecular diagnosis and in selecting patients who would benefit from pharmacological correction of this defect. Acquired cases meanwhile stem from the co-occurrence of myasthenia gravis or Lambert-Eaton myasthenic syndrome with an immune-mediated myopathy, which may be due to paraneoplastic disorders or exposure to immune checkpoint inhibitors.
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Affiliation(s)
- Stefan Nicolau
- Department of Neurology, Mayo Clinic, Rochester, Minnesota
| | - Justin C Kao
- Department of Neurology, Auckland City Hospital, Auckland, New Zealand
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39
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van Tol W, Michelakakis H, Georgiadou E, van den Bergh P, Moraitou M, Papadimas GK, Papadopoulos C, Huijben K, Alsady M, Willemsen MA, Lefeber DJ. Toward understanding tissue-specific symptoms in dolichol-phosphate-mannose synthesis disorders; insight from DPM3-CDG. J Inherit Metab Dis 2019; 42:984-992. [PMID: 30931530 DOI: 10.1002/jimd.12095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 03/25/2019] [Indexed: 12/21/2022]
Abstract
The congenital disorders of glycosylation (CDG) are inborn errors of metabolism with a great genetic heterogeneity. Most CDG are caused by defects in the N-glycan biosynthesis, leading to multisystem phenotypes. However, the occurrence of tissue-restricted clinical symptoms in the various defects in dolichol-phosphate-mannose (DPM) synthesis remains unexplained. To deepen our understanding of the tissue-specific characteristics of defects in the DPM synthesis pathway, we investigated N-glycosylation and O-mannosylation in skeletal muscle of three DPM3-CDG patients presenting with muscle dystrophy and hypo-N-glycosylation of serum transferrin in only two of them. In the three patients, O-mannosylation of alpha-dystroglycan (αDG) was strongly reduced and western blot analysis of beta-dystroglycan (βDG) N-glycosylation revealed a consistent lack of one N-glycan in skeletal muscle. Recently, defective N-glycosylation of βDG has been reported in patients with mutations in guanosine-diphosphate-mannose pyrophosphorylase B (GMPPB). Thus, we suggest that aberrant O-glycosylation of αDG and N-glycosylation of βDG in skeletal muscle is indicative of a defect in the DPM synthesis pathway. Further studies should address to what extent hypo-N-glycosylation of βDG or other skeletal muscle proteins contribute to the phenotype of patients with defects in DPM synthesis. Our findings contribute to our understanding of the tissue-restricted phenotype of DPM3-CDG and other defects in the DPM synthesis pathway.
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Affiliation(s)
- Walinka van Tol
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Helen Michelakakis
- Department of Enzymology and Cellular Function, Institute of Child Health, Athens, Greece
| | - Elissavet Georgiadou
- First Department of Pediatrics, University of Athens, Aghia Sophia Children's Hospital, Athens, Greece
| | - Peter van den Bergh
- Neuromuscular Reference Center, University Hospital St-Luc, University of Louvain, Brussels, Belgium
| | - Marina Moraitou
- Department of Enzymology and Cellular Function, Institute of Child Health, Athens, Greece
| | - George K Papadimas
- First Department of Neurology, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Constantinos Papadopoulos
- First Department of Neurology, Eginition Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Karin Huijben
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mohammad Alsady
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michèl A Willemsen
- Department of Pediatric Neurology, Amalia Children's Hospital, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Dirk J Lefeber
- Department of Neurology, Donders Institute for Brain, Cognition and Behavior, Radboud University Medical Center, Nijmegen, The Netherlands
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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40
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Nicolau S, Liewluck T, Shen XM, Selcen D, Engel AG, Milone M. A homozygous mutation in GMPPB leads to centronuclear myopathy with combined pre- and postsynaptic defects of neuromuscular transmission. Neuromuscul Disord 2019; 29:614-617. [PMID: 31378432 DOI: 10.1016/j.nmd.2019.07.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/14/2019] [Accepted: 07/02/2019] [Indexed: 11/26/2022]
Abstract
Mutations in GMPPB cause a wide spectrum of neuromuscular syndromes, including muscular dystrophies and congenital myasthenic syndrome. The mechanisms by which GMPPB mutations impair neuromuscular transmission however remain incompletely understood. We expand here upon a previous report of one such patient presenting with a myopathy-congenital myasthenic syndrome overlap phenotype. Fatigable proximal muscle weakness developed gradually between 13 and 25 years of age, with subsequent stabilization. Low-frequency repetitive nerve stimulation showed a decrement, while a muscle biopsy demonstrated the presence of a centronuclear myopathy. Genetic testing identified a homozygous c.458C > T (p.Thr153Ile) variant in GMPPB. In-vitro microelectrode recordings and ultrastructural studies showed impairment of both pre- and postsynaptic neuromuscular transmission, thus demonstrating the presence of not only postsynaptic, but also presynaptic pathology in GMPPB-related disorders.
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Affiliation(s)
- Stefan Nicolau
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, United States
| | - Teerin Liewluck
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, United States
| | - Xin-Ming Shen
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, United States
| | - Duygu Selcen
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, United States
| | - Andrew G Engel
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, United States
| | - Margherita Milone
- Department of Neurology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, United States.
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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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42
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Tian WT, Zhou HY, Zhan FX, Zhu ZY, Yang J, Chen SD, Luan XH, Cao L. Lysosomal degradation of GMPPB is associated with limb-girdle muscular dystrophy type 2T. Ann Clin Transl Neurol 2019; 6:1062-1071. [PMID: 31211170 PMCID: PMC6562035 DOI: 10.1002/acn3.787] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 04/07/2019] [Accepted: 04/08/2019] [Indexed: 12/03/2022] Open
Abstract
Objective GDP‐mannose pyrophosphorylase B (GMPPB) related phenotype spectrum ranges widely from congenital myasthenic syndrome (CMS), limb‐girdle muscular dystrophy type 2T (LGMD 2T) to severe congenital muscle‐eye‐brain syndrome. Our study investigates the clinicopathologic features of a patient with novel GMPPB mutations and explores the pathogenetic mechanism. Methods The patient was a 22‐year‐old woman with chronic proximal limb weakness for 9 years without cognitive deterioration. Weakness became worse after fatigue. Elevated serum creatine kinase and decrements on repetitive nerve stimulation test were recorded. MRI showed fatty infiltration in muscles of lower limbs and shoulder girdle on T1 sequence. Open muscle biopsy and genetic analysis were performed. Results Muscle biopsy showed myogenic changes. Two missense mutations in GMPPB gene (c.803T>C and c.1060G>A) were identified in the patient. Western blotting and immunostaining showed GMPPB and α‐dystroglycan deficiency in the patient's muscle. In vitro, mutant GMPPB forming cytoplasmic aggregates completely colocalized with microtubule‐associated protein 1 light chain 3‐II (LC3‐II), a classical marker of autophagosome. Degradation of GMPPB was accompanied by an upregulation of LC3‐II, which could be restored by lysosomal inhibitor leupeptin. Interpretation We identified two novel GMPPB mutations causing overlap phenotype between LGMD 2T and CMS. We provided the initial evidence that mutant GMPPB colocalizes with autophagosome at subcellular level. GMPPB mutants degraded by autophagy‐lysosome pathway is associated with LGMD 2T. This study shed the light into the enzyme replacement which could become one of the therapeutic targets in the future study.
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Affiliation(s)
- Wo-Tu Tian
- Department of Neurology Rui Jin Hospital & Rui Jin Hospital North Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
| | - Hai-Yan Zhou
- Department of Neurology Rui Jin Hospital & Rui Jin Hospital North Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
| | - Fei-Xia Zhan
- Department of Neurology Rui Jin Hospital & Rui Jin Hospital North Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
| | - Ze-Yu Zhu
- Department of Neurology Rui Jin Hospital & Rui Jin Hospital North Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
| | - Jie Yang
- Core Facility of Basic Medical Sciences Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
| | - Sheng-Di Chen
- Department of Neurology Rui Jin Hospital & Rui Jin Hospital North Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
| | - Xing-Hua Luan
- Department of Neurology Rui Jin Hospital & Rui Jin Hospital North Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
| | - Li Cao
- Department of Neurology Rui Jin Hospital & Rui Jin Hospital North Shanghai Jiao Tong University School of Medicine Shanghai 200025 China
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43
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Sanders DB, Arimura K, Cui L, Ertaş M, Farrugia ME, Gilchrist J, Kouyoumdjian JA, Padua L, Pitt M, Stålberg E. Guidelines for single fiber EMG. Clin Neurophysiol 2019; 130:1417-1439. [PMID: 31080019 DOI: 10.1016/j.clinph.2019.04.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/30/2019] [Accepted: 04/06/2019] [Indexed: 12/13/2022]
Abstract
This document is the consensus of international experts on the current status of Single Fiber EMG (SFEMG) and the measurement of neuromuscular jitter with concentric needle electrodes (CNE - CN-jitter). The panel of authors was chosen based on their particular interests and previous publications within a specific area of SFEMG or CN-jitter. Each member of the panel was asked to submit a section on their particular area of interest and these submissions were circulated among the panel members for edits and comments. This process continued until a consensus was reached. Donald Sanders and Erik Stålberg then edited the final document.
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Affiliation(s)
| | - Kimiyoshi Arimura
- Department of Neurology and Geriatrics, Kagoshima University, Graduate School of Medical and Dental Sciences, Kagoshima, Japan.
| | - LiYing Cui
- Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, Beijing, China.
| | | | | | - James Gilchrist
- Southern Illinois University School of Medicine, Springfield, IL USA.
| | | | - Luca Padua
- Fondazione Policlinico Universitario Agostino Gemelli IRCCS, Department of Geriatrics, Neurosciences and Orthopaedics, Università Cattolica del Sacro Cuore, Rome, Italy.
| | - Matthew Pitt
- Department of Clinical Neurophysiology, Great Ormond Street Hospital, London, UK.
| | - Erik Stålberg
- Department of Clinical Neurophysiology, Uppsala University, Uppsala, Sweden.
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44
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Kanagawa M. Myo-Glyco disease Biology: Genetic Myopathies Caused by Abnormal Glycan Synthesis and Degradation. J Neuromuscul Dis 2019; 6:175-187. [PMID: 30856120 PMCID: PMC6598100 DOI: 10.3233/jnd-180369] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Glycosylation is a major form of post-translational modification and plays various important roles in organisms by modifying proteins or lipids, which generates functional variability and can increase their stability. Because of the physiological importance of glycosylation, defects in genes encoding proteins involved in glycosylation or glycan degradation are sometimes associated with human diseases. A number of genetic neuromuscular diseases are caused by abnormal glycan modification or degeneration. Heterogeneous and complex modification machinery, and difficulties in structural and functional analysis of glycans have impeded the understanding of how glycosylation contributes to pathology. However, recent rapid advances in glycan and genetic analyses, as well as accumulating genetic and clinical information have greatly contributed to identifying glycan structures and modification enzymes, which has led to breakthroughs in the understanding of the molecular pathogenesis of various diseases and the possible development of therapeutic strategies. For example, studies on the relationship between glycosylation and muscular dystrophy in the last two decades have significantly impacted the fields of glycobiology and neuromyology. In this review, the basis of glycan structure and biosynthesis will be briefly explained, and then molecular pathogenesis and therapeutic concepts related to neuromuscular diseases will be introduced from the point of view of the life cycle of a glycan molecule.
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Affiliation(s)
- Motoi Kanagawa
- Division of Molecular Brain Science, Kobe University Graduate School of Medicine, Japan
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45
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Issop Y, Hathazi D, Khan MM, Rudolf R, Weis J, Spendiff S, Slater CR, Roos A, Lochmüller H. GFPT1 deficiency in muscle leads to myasthenia and myopathy in mice. Hum Mol Genet 2019; 27:3218-3232. [PMID: 29905857 PMCID: PMC6121184 DOI: 10.1093/hmg/ddy225] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 06/05/2018] [Indexed: 11/13/2022] Open
Abstract
Glutamine-fructose-6-phosphate transaminase 1 (GFPT1) is the rate-limiting enzyme in the hexosamine biosynthetic pathway which yields precursors required for protein and lipid glycosylation. Mutations in GFPT1 and other genes downstream of this pathway cause congenital myasthenic syndrome (CMS) characterized by fatigable muscle weakness owing to impaired neurotransmission. The precise pathomechanisms at the neuromuscular junction (NMJ) owing to a deficiency in GFPT1 is yet to be discovered. One of the challenges we face is the viability of Gfpt1−/− knockout mice. In this study, we use Cre/LoxP technology to generate a muscle-specific GFPT1 knockout mouse model, Gfpt1tm1d/tm1d, characteristic of the human CMS phenotype. Our data suggest a critical role for muscle derived GFPT1 in the development of the NMJ, neurotransmission, skeletal muscle integrity and highlight that a deficiency in skeletal muscle alone is sufficient to cause morphological postsynaptic NMJ changes that are accompanied by presynaptic alterations despite the conservation of neuronal GFPT1 expression. In addition to the conventional morphological NMJ changes and fatigable muscle weakness, Gfpt1tm1d/tm1d mice display a progressive myopathic phenotype with the presence of tubular aggregates in muscle, characteristic of the GFPT1-CMS phenotype. We further identify an upregulation of skeletal muscle proteins glypican-1, farnesyltransferase/geranylgeranyltransferase type-1 subunit α and muscle-specific kinase, which are known to be involved in the differentiation and maintenance of the NMJ. The Gfpt1tm1d/tm1d model allows for further investigation of pathophysiological consequences on genes and pathways downstream of GFPT1 likely to involve misglycosylation or hypoglycosylation of NMJs and muscle targets.
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Affiliation(s)
- Yasmin Issop
- John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle, UK
| | - Denisa Hathazi
- Leibniz-Institut für Analytische Wissenschaften-ISAS e.V, Dortmund, Germany
| | - Muzamil Majid Khan
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Rüdiger Rudolf
- Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany.,Interdisciplinary Center for Neurosciences, University of Heidelberg, Heidelberg, Germany.,Institute of Molecular and Cell Biology, Mannheim University of Applied Sciences, Mannheim, Germany
| | - Joachim Weis
- Institute of Neuropathology, RWTH Aachen University Hospital, Aachen, Germany
| | - Sally Spendiff
- John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle, UK
| | - Clarke R Slater
- Institute of Neuroscience, Newcastle University, Newcastle, UK
| | - Andreas Roos
- John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle, UK.,Leibniz-Institut für Analytische Wissenschaften-ISAS e.V, Dortmund, Germany
| | - Hanns Lochmüller
- John Walton Muscular Dystrophy Research Centre, MRC Centre for Neuromuscular Diseases, Institute of Genetic Medicine, Newcastle University, Newcastle, UK.,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, Catalonia, Spain
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46
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Abstract
OBJECTIVES Congenital myasthenic syndromes (CMSs) are a genotypically and phenotypically heterogeneous group of neuromuscular disorders, which have in common an impaired neuromuscular transmission. Since the field of CMSs is steadily expanding, the present review aimed at summarizing and discussing current knowledge and recent advances concerning the etiology, clinical presentation, diagnosis, and treatment of CMSs. METHODS Systematic literature review. RESULTS Currently, mutations in 32 genes are made responsible for autosomal dominant or autosomal recessive CMSs. These mutations concern 8 presynaptic, 4 synaptic, 15 post-synaptic, and 5 glycosilation proteins. These proteins function as ion-channels, enzymes, or structural, signalling, sensor, or transporter proteins. The most common causative genes are CHAT, COLQ, RAPSN, CHRNE, DOK7, and GFPT1. Phenotypically, these mutations manifest as abnormal fatigability or permanent or fluctuating weakness of extra-ocular, facial, bulbar, axial, respiratory, or limb muscles, hypotonia, or developmental delay. Cognitive disability, dysmorphism, neuropathy, or epilepsy are rare. Low- or high-frequency repetitive nerve stimulation may show an abnormal increment or decrement, and SF-EMG an increased jitter or blockings. Most CMSs respond favourably to acetylcholine-esterase inhibitors, 3,4-diamino-pyridine, salbutamol, albuterol, ephedrine, fluoxetine, or atracurium. CONCLUSIONS CMSs are an increasingly recognised group of genetically transmitted defects, which usually respond favorably to drugs enhancing the neuromuscular transmission. CMSs need to be differentiated from neuromuscular disorders due to muscle or nerve dysfunction.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Messerli Institute, Veterinary University of Vienna, Postfach 20, 1180, Vienna, Austria.
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47
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Coleman JRI, Bryois J, Gaspar HA, Jansen PR, Savage JE, Skene N, Plomin R, Muñoz-Manchado AB, Linnarsson S, Crawford G, Hjerling-Leffler J, Sullivan PF, Posthuma D, Breen G. Biological annotation of genetic loci associated with intelligence in a meta-analysis of 87,740 individuals. Mol Psychiatry 2019; 24:182-197. [PMID: 29520040 PMCID: PMC6330082 DOI: 10.1038/s41380-018-0040-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 11/13/2017] [Accepted: 01/02/2018] [Indexed: 11/08/2022]
Abstract
Variance in IQ is associated with a wide range of health outcomes, and 1% of the population are affected by intellectual disability. Despite a century of research, the fundamental neural underpinnings of intelligence remain unclear. We integrate results from genome-wide association studies (GWAS) of intelligence with brain tissue and single cell gene expression data to identify tissues and cell types associated with intelligence. GWAS data for IQ (N = 78,308) were meta-analyzed with a study comparing 1247 individuals with mean IQ ~170 to 8185 controls. Genes associated with intelligence implicate pyramidal neurons of the somatosensory cortex and CA1 region of the hippocampus, and midbrain embryonic GABAergic neurons. Tissue-specific analyses find the most significant enrichment for frontal cortex brain expressed genes. These results suggest specific neuronal cell types and genes may be involved in intelligence and provide new hypotheses for neuroscience experiments using model systems.
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Affiliation(s)
- Jonathan R I Coleman
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK
- NIHR Biomedical Research Centre for Mental Health, South London and Maudsley NHS Trust, London, SE5 8AF, UK
| | - Julien Bryois
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Héléna A Gaspar
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK
| | - Philip R Jansen
- Department of Complex Trait Genetics, VU University, Center for Neurogenomics and Cognitive Research, Amsterdam, 1081 HV, The Netherlands
- Department of Child and Adolescent Psychiatry, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Jeanne E Savage
- Department of Complex Trait Genetics, VU University, Center for Neurogenomics and Cognitive Research, Amsterdam, 1081 HV, The Netherlands
| | - Nathan Skene
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Robert Plomin
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK
| | - Ana B Muñoz-Manchado
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Sten Linnarsson
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Greg Crawford
- Center for Genomic and Computational Biology, Duke University, Durham, NC, 27708, USA
- Department of Pediatrics, Medical Genetics Division, Duke University, Durham, NC, 27708, USA
| | - Jens Hjerling-Leffler
- Laboratory of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, SE-17177, Sweden
| | - Patrick F Sullivan
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, SE-17177, Sweden
- Departments of Genetics, University of North Carolina, Chapel Hill, NC, 27599-7264, USA
| | - Danielle Posthuma
- Department of Complex Trait Genetics, VU University, Center for Neurogenomics and Cognitive Research, Amsterdam, 1081 HV, The Netherlands.
- Department of Clinical Genetics, VU University Medical Center (VUMC), Neuroscience Campus Amsterdam, Amsterdam, 1081 HV, The Netherlands.
| | - Gerome Breen
- MRC Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, SE5 8AF, UK.
- NIHR Biomedical Research Centre for Mental Health, South London and Maudsley NHS Trust, London, SE5 8AF, UK.
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48
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Targeted therapies for congenital myasthenic syndromes: systematic review and steps towards a treatabolome. Emerg Top Life Sci 2019; 3:19-37. [PMID: 30931400 PMCID: PMC6436731 DOI: 10.1042/etls20180100] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Despite recent scientific advances, most rare genetic diseases — including most neuromuscular diseases — do not currently have curative gene-based therapies available. However, in some cases, such as vitamin, cofactor or enzyme deficiencies, channelopathies and disorders of the neuromuscular junction, a confirmed genetic diagnosis provides guidance on treatment, with drugs available that may significantly alter the disease course, improve functional ability and extend life expectancy. Nevertheless, many treatable patients remain undiagnosed or do not receive treatment even after genetic diagnosis. The growth of computer-aided genetic analysis systems that enable clinicians to diagnose their undiagnosed patients has not yet been matched by genetics-based decision-support systems for treatment guidance. Generating a ‘treatabolome’ of treatable variants and the evidence for the treatment has the potential to increase treatment rates for treatable conditions. Here, we use the congenital myasthenic syndromes (CMS), a group of clinically and genetically heterogeneous but frequently treatable neuromuscular conditions, to illustrate the steps in the creation of a treatabolome for rare inherited diseases. We perform a systematic review of the evidence for pharmacological treatment of each CMS type, gathering evidence from 207 studies of over 1000 patients and stratifying by genetic defect, as treatment varies depending on the underlying cause. We assess the strength and quality of the evidence and create a dataset that provides the foundation for a computer-aided system to enable clinicians to gain easier access to information about treatable variants and the evidence they need to consider.
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Nickolls AR, Bönnemann CG. The roles of dystroglycan in the nervous system: insights from animal models of muscular dystrophy. Dis Model Mech 2018; 11:11/12/dmm035931. [PMID: 30578246 PMCID: PMC6307911 DOI: 10.1242/dmm.035931] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Dystroglycan is a cell membrane protein that binds to the extracellular matrix in a variety of mammalian tissues. The α-subunit of dystroglycan (αDG) is heavily glycosylated, including a special O-mannosyl glycoepitope, relying upon this unique glycosylation to bind its matrix ligands. A distinct group of muscular dystrophies results from specific hypoglycosylation of αDG, and they are frequently associated with central nervous system involvement, ranging from profound brain malformation to intellectual disability without evident morphological defects. There is an expanding literature addressing the function of αDG in the nervous system, with recent reports demonstrating important roles in brain development and in the maintenance of neuronal synapses. Much of these data are derived from an increasingly rich array of experimental animal models. This Review aims to synthesize the information from such diverse models, formulating an up-to-date understanding about the various functions of αDG in neurons and glia of the central and peripheral nervous systems. Where possible, we integrate these data with our knowledge of the human disorders to promote translation from basic mechanistic findings to clinical therapies that take the neural phenotypes into account. Summary: Dystroglycan is a ubiquitous matrix receptor linked to brain and muscle disease. Unraveling the functions of this protein will inform basic and translational research on neural development and muscular dystrophies.
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Affiliation(s)
- Alec R Nickolls
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.,Department of Neuroscience, Brown University, Providence, RI 02912, USA
| | - Carsten G Bönnemann
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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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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