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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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2
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Sakson R, Beedgen L, Bernhard P, Alp KM, Lübbehusen N, Röth R, Niesler B, Luzarowski M, Shevchuk O, Mayer MP, Thiel C, Ruppert T. Targeted Proteomics Reveals Quantitative Differences in Low-Abundance Glycosyltransferases of Patients with Congenital Disorders of Glycosylation. Int J Mol Sci 2024; 25:1191. [PMID: 38256263 PMCID: PMC10816918 DOI: 10.3390/ijms25021191] [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: 12/23/2023] [Revised: 01/11/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
Protein glycosylation is an essential post-translational modification in all domains of life. Its impairment in humans can result in severe diseases named congenital disorders of glycosylation (CDGs). Most of the glycosyltransferases (GTs) responsible for proper glycosylation are polytopic membrane proteins that represent challenging targets in proteomics. We established a multiple reaction monitoring (MRM) assay to comprehensively quantify GTs involved in the processes of N-glycosylation and O- and C-mannosylation in the endoplasmic reticulum. High robustness was achieved by using an enriched membrane protein fraction of isotopically labeled HEK 293T cells as an internal protein standard. The analysis of primary skin fibroblasts from eight CDG type I patients with impaired ALG1, ALG2, and ALG11 genes, respectively, revealed a substantial reduction in the corresponding protein levels. The abundance of the other GTs, however, remained unchanged at the transcript and protein levels, indicating that there is no fail-safe mechanism for the early steps of glycosylation in the endoplasmic reticulum. The established MRM assay was shared with the scientific community via the commonly used open source Skyline software environment, including Skyline Batch for automated data analysis. We demonstrate that another research group could easily reproduce all analysis steps, even while using different LC-MS hardware.
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Affiliation(s)
- Roman Sakson
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
- Heidelberg Biosciences International Graduate School (HBIGS), Heidelberg University, 69120 Heidelberg, Germany
| | - Lars Beedgen
- Center for Child and Adolescent Medicine, Department Pediatrics I, Heidelberg University, 69120 Heidelberg, Germany
| | - Patrick Bernhard
- Institute for Surgical Pathology, Medical Center—University of Freiburg, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - K. Merve Alp
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Nicole Lübbehusen
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Ralph Röth
- nCounter Core Facility, Institute of Human Genetics, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Beate Niesler
- nCounter Core Facility, Institute of Human Genetics, University Hospital Heidelberg, 69120 Heidelberg, Germany
- Interdisciplinary Center for Neurosciences, Heidelberg University, 69120 Heidelberg, Germany
| | - Marcin Luzarowski
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Olga Shevchuk
- Department of Immunodynamics, Institute of Experimental Immunology and Imaging, University Hospital Essen, 45147 Essen, Germany
| | - Matthias P. Mayer
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Christian Thiel
- Center for Child and Adolescent Medicine, Department Pediatrics I, Heidelberg University, 69120 Heidelberg, Germany
| | - Thomas Ruppert
- Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
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3
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Farshadyeganeh P, Nazim M, Zhang R, Ohkawara B, Nakajima K, Rahman MA, Nasrin F, Ito M, Takeda JI, Ohe K, Miyasaka Y, Ohno T, Masuda A, Ohno K. Splicing regulation of GFPT1 muscle-specific isoform and its roles in glucose metabolisms and neuromuscular junction. iScience 2023; 26:107746. [PMID: 37744035 PMCID: PMC10514471 DOI: 10.1016/j.isci.2023.107746] [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: 05/10/2023] [Revised: 07/29/2023] [Accepted: 08/24/2023] [Indexed: 09/26/2023] Open
Abstract
Glutamine:fructose-6-phosphate transaminase 1 (GFPT1) is the rate-limiting enzyme of the hexosamine biosynthetic pathway (HBP). A 54-bp exon 9 of GFPT1 is specifically included in skeletal and cardiac muscles to generate a long isoform of GFPT1 (GFPT1-L). We showed that SRSF1 and Rbfox1/2 cooperatively enhance, and hnRNP H/F suppresses, the inclusion of human GFPT1 exon 9 by modulating recruitment of U1 snRNP. Knockout (KO) of GFPT1-L in skeletal muscle markedly increased the amounts of GFPT1 and UDP-HexNAc, which subsequently suppressed the glycolytic pathway. Aged KO mice showed impaired insulin-mediated glucose uptake, as well as muscle weakness and fatigue likely due to abnormal formation and maintenance of the neuromuscular junction. Taken together, GFPT1-L is likely to be acquired in evolution in mammalian striated muscles to attenuate the HBP for efficient glycolytic energy production, insulin-mediated glucose uptake, and the formation and maintenance of the neuromuscular junction.
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Affiliation(s)
- Paniz Farshadyeganeh
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Mohammad Nazim
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA
| | - Ruchen Zhang
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Bisei Ohkawara
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Kazuki Nakajima
- Institute for Glyco-core Research (iGCORE), Gifu University, Gifu 501-1193, Japan
| | - Mohammad Alinoor Rahman
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Biochemistry and Molecular Biology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, USA
| | - Farhana Nasrin
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Biochemistry and Molecular Biology, Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR 72205, USA
| | - Mikako Ito
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Jun-ichi Takeda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Kenji Ohe
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Faculty of Pharmaceutical Sciences, Fukuoka University, Fukuoka 814-0180, Japan
| | - Yuki Miyasaka
- Division of Experimental Animals, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Tamio Ohno
- Division of Experimental Animals, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Akio Masuda
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Kinji Ohno
- Division of Neurogenetics, Center for Neurological Diseases and Cancer, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
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4
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Salih MA. The Meryon Lecture at the 24th annual meeting of the Meryon Society, St. Anne's College, Oxford, UK, 15th July 2022: Neuromuscular diseases in the Arab population. Neuromuscul Disord 2023; 33:792-799. [PMID: 37679229 DOI: 10.1016/j.nmd.2023.08.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Affiliation(s)
- Mustafa A Salih
- Consultant Pediatric Neurologist, Health Sector, King Abdulaziz City for Science and Technology, Riyadh 11442, Saudi Arabia.
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5
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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: 26] [Impact Index Per Article: 26.0] [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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6
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Paprocka J. Neurological Consequences of Congenital Disorders of Glycosylation. ADVANCES IN NEUROBIOLOGY 2023; 29:219-253. [PMID: 36255677 DOI: 10.1007/978-3-031-12390-0_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The chapter is devoted to neurological aspects of congenital disorders of glycosylation (CDG). At the beginning, the various types of CDG with neurological presentation of symptoms are summarized. Then, the occurrence of various neurological constellation of abnormalities (for example: epilepsy, brain anomalies on neuroimaging, ataxia, stroke-like episodes, autistic features) in different CDG types are discussed followed by data on possible biomarkers and limited treatment options.
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Affiliation(s)
- Justyna Paprocka
- Department of Pediatric Neurology, Faculty of Medical Sciences, Medical University of Silesia, Katowice, Poland.
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7
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Wang CD, Xu S, Chen S, Chen ZH, Dean N, Wang N, Gao XD. An in vitro assay for enzymatic studies on human ALG13/14 heterodimeric UDP-N-acetylglucosamine transferase. Front Cell Dev Biol 2022; 10:1008078. [PMID: 36200043 PMCID: PMC9527342 DOI: 10.3389/fcell.2022.1008078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
The second step of eukaryotic lipid-linked oligosaccharide (LLO) biosynthesis is catalyzed by the conserved ALG13/ALG14 heterodimeric UDP-N-acetylglucosamine transferase (GnTase). In humans, mutations in ALG13 or ALG14 lead to severe neurological disorders with a multisystem phenotype, known as ALG13/14-CDG (congenital disorders of glycosylation). How these mutations relate to disease is unknown because to date, a reliable GnTase assay for studying the ALG13/14 complex is lacking. Here we describe the development of a liquid chromatography/mass spectrometry-based quantitative GnTase assay using chemically synthesized GlcNAc-pyrophosphate-dolichol as the acceptor and purified human ALG13/14 dimeric enzyme. This assay enabled us to demonstrate that in contrast to the literature, only the shorter human ALG13 isoform 2, but not the longer isoform 1 forms a functional complex with ALG14 that participates in LLO synthesis. The longer ALG13 isoform 1 does not form a complex with ALG14 and therefore lacks GnTase activity. Importantly, we further established a quantitative assay for GnTase activities of ALG13- and ALG14-CDG variant alleles, demonstrating that GnTase deficiency is the cause of ALG13/14-CDG phenotypes.
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Affiliation(s)
- Chun-Di Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Si Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Shuai Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zheng-Hui Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, New York City, NY, United States
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- *Correspondence: Xiao-Dong Gao, ; Ning Wang,
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- *Correspondence: Xiao-Dong Gao, ; Ning Wang,
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8
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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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9
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Katata Y, Uneoka S, Saijyo N, Aihara Y, Miyazoe T, Koyamaishi S, Oikawa Y, Ito Y, Abe Y, Numata-Uematsu Y, Takayama J, Kikuchi A, Tamiya G, Uematsu M, Kure S. The longest reported sibling survivors of a severe form of congenital myasthenic syndrome with the ALG14 pathogenic variant. Am J Med Genet A 2021; 188:1293-1298. [PMID: 34971077 DOI: 10.1002/ajmg.a.62629] [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: 07/23/2021] [Revised: 10/26/2021] [Accepted: 12/07/2021] [Indexed: 11/06/2022]
Abstract
Congenital myasthenic syndromes (CMS) is a group of diseases that causes abnormalities at the neuromuscular junction owing to genetic anomalies. The pathogenic variant in ALG14 results in a severe pathological form of CMS causing end-plate acetylcholine receptor deficiency. Here, we report the cases of two siblings with CMS associated with a novel variant in ALG14. Immediately after birth, they showed hypotonia and multiple joint contractures with low Apgar scores. Ptosis, low-set ears, and high-arched palate were noted. Deep tendon reflexes were symmetrical. They showed worsening swallowing and respiratory problems; hence, nasal feeding and tracheotomy were performed. Cranial magnetic resonance imaging scans revealed delayed myelination and cerebral atrophy. Exome sequencing indicated that the siblings had novel compound heterozygous missense variants, c.590T>G (p.Val197Gly) and c.433G>A (p.Gly145Arg), in exon 4 of ALG14. Repetitive nerve stimulation test showed an abnormal decrease in compound muscle action potential. After treatment with pyridostigmine, the time off the respirator increased. Their epileptic seizures were well controlled by anti-epileptic drugs. Their clinical course is stable even now at the ages of 5 and 2 years, making them the longest reported survivors of a severe form of CMS with the ALG14 variant thus far.
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Affiliation(s)
- Yu Katata
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Saki Uneoka
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Naoya Saijyo
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Yu Aihara
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Takamitsu Miyazoe
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Shun Koyamaishi
- Department of Pediatrics, Hachinohe City Hospital, Hachinohe, Japan
| | - Yoshitsugu Oikawa
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Yuya Ito
- Department of Pediatrics, Hachinohe City Hospital, Hachinohe, Japan.,Department of Neonatology, Aomori Prefectural Central Hospital, Hachinohe, Japan
| | - Yu Abe
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan.,Department of Pediatrics, Tsuruoka Municipal Shonai Hospital, Tsuruoka, Japan
| | | | - Jun Takayama
- Department of AI and Innovative Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.,Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan.,Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project, Tokyo, Japan
| | - Atsuo Kikuchi
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Gen Tamiya
- Department of AI and Innovative Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.,Tohoku Medical Megabank Organization, Tohoku University, Sendai, Japan.,Statistical Genetics Team, RIKEN Center for Advanced Intelligence Project, Tokyo, Japan
| | - Mitsugu Uematsu
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
| | - Shigeo Kure
- Department of Pediatrics, Tohoku University School of Medicine, Sendai, Japan
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10
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Gang Q, Bettencourt C, Brady S, Holton JL, Healy EG, McConville J, Morrison PJ, Ripolone M, Violano R, Sciacco M, Moggio M, Mora M, Mantegazza R, Zanotti S, Wang Z, Yuan Y, Liu WW, Beeson D, Hanna M, Houlden H. Genetic defects are common in myopathies with tubular aggregates. Ann Clin Transl Neurol 2021; 9:4-15. [PMID: 34908252 PMCID: PMC8791796 DOI: 10.1002/acn3.51477] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 10/12/2021] [Accepted: 10/27/2021] [Indexed: 12/17/2022] Open
Abstract
Objective A group of genes have been reported to be associated with myopathies with tubular aggregates (TAs). Many cases with TAs still lack of genetic clarification. This study aims to explore the genetic background of cases with TAs in order to improve our knowledge of the pathogenesis of these rare pathological structures. Methods Thirty‐three patients including two family members with biopsy confirmed TAs were collected. Whole‐exome sequencing was performed on 31 unrelated index patients and a candidate gene search strategy was conducted. The identified variants were confirmed by Sanger sequencing. The wild‐type and the mutant p.Ala11Thr of ALG14 were transfected into human embryonic kidney 293 cells (HEK293), and western blot analysis was performed to quantify protein expression levels. Results Eleven index cases (33%) were found to have pathogenic variant or likely pathogenic variants in STIM1, ORAI1, PGAM2, SCN4A, CASQ1 and ALG14. Among them, the c.764A>T (p.Glu255Val) in STIM1 and the c.1333G>C (p.Val445Leu) in SCN4A were novel. Western blot analysis showed that the expression of ALG14 protein was severely reduced in the mutant ALG14 HEK293 cells (p.Ala11Thr) compared with wild type. The ALG14 variants might be associated with TAs in patients with complex multisystem disorders. Interpretation This study expands the phenotypic and genotypic spectrums of myopathies with TAs. Our findings further confirm previous hypothesis that genes related with calcium signalling pathway and N‐linked glycosylation pathway are the main genetic causes of myopathies with TAs.
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Affiliation(s)
- Qiang Gang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, 100034, China.,Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - Conceição Bettencourt
- Queen Square Brain Bank for Neurological Disorders, London, UK.,Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - Stefen Brady
- Oxford Muscle Service, John Radcliffe Hospital, Oxford, UK
| | - Janice L Holton
- MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,Queen Square Brain Bank for Neurological Disorders, London, UK
| | - Estelle G Healy
- Department of Neuropathology, Royal Victoria Hospital, Belfast, Northern Ireland
| | - John McConville
- Department of Neurology, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Patrick J Morrison
- Department of Genetic Medicine, Belfast City Hospital, Belfast, BT9 7AB, UK
| | - Michela Ripolone
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Raffaella Violano
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Monica Sciacco
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Maurizio Moggio
- Neuromuscular and Rare Diseases Unit, Department of Neuroscience, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Dino Ferrari Centre, University of Milan, Milan, Italy
| | - Marina Mora
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Isitituto Neurologico C. Besta, Milano, Italy
| | - Renato Mantegazza
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Isitituto Neurologico C. Besta, Milano, Italy
| | - Simona Zanotti
- Neuromuscular Diseases and Neuroimmunology Unit, Fondazione IRCCS Isitituto Neurologico C. Besta, Milano, Italy
| | - Zhaoxia Wang
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, 100034, China
| | - Yun Yuan
- Department of Neurology, Peking University First Hospital, 8 Xishiku Street, Xicheng District, Beijing, 100034, China.,Beijing Key Laboratory of Neurovascular Disease Discovery, Beijing, 100034, China
| | - Wei-Wei Liu
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - David Beeson
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Michael Hanna
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,MRC Centre for Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.,Neurogenetics Laboratory, UCL Queen Square Institute of Neurology, Queen Square, WC1N 3BG, London, UK
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11
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Padilla-Mejia NE, Makarov AA, Barlow LD, Butterfield ER, Field MC. Evolution and diversification of the nuclear envelope. Nucleus 2021; 12:21-41. [PMID: 33435791 PMCID: PMC7889174 DOI: 10.1080/19491034.2021.1874135] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic cells arose ~1.5 billion years ago, with the endomembrane system a central feature, facilitating evolution of intracellular compartments. Endomembranes include the nuclear envelope (NE) dividing the cytoplasm and nucleoplasm. The NE possesses universal features: a double lipid bilayer membrane, nuclear pore complexes (NPCs), and continuity with the endoplasmic reticulum, indicating common evolutionary origin. However, levels of specialization between lineages remains unclear, despite distinct mechanisms underpinning various nuclear activities. Several distinct modes of molecular evolution facilitate organellar diversification and to understand which apply to the NE, we exploited proteomic datasets of purified nuclear envelopes from model systems for comparative analysis. We find enrichment of core nuclear functions amongst the widely conserved proteins to be less numerous than lineage-specific cohorts, but enriched in core nuclear functions. This, together with consideration of additional evidence, suggests that, despite a common origin, the NE has evolved as a highly diverse organelle with significant lineage-specific functionality.
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Affiliation(s)
- Norma E. Padilla-Mejia
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Alexandr A. Makarov
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Lael D. Barlow
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Erin R. Butterfield
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
| | - Mark C. Field
- Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dundee, UK
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České, Czech Republic
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12
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Novel pathogenic ALG2 mutation causing congenital myasthenic syndrome: A case report. Neuromuscul Disord 2021; 32:80-83. [PMID: 34980536 DOI: 10.1016/j.nmd.2021.11.012] [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: 04/04/2021] [Revised: 11/18/2021] [Accepted: 11/23/2021] [Indexed: 11/23/2022]
Abstract
ALG2 mutations are extremely rare causes of congenital myasthenic syndromes (CMS). The clinical phenotype and treatment response is therefore not well described. We present the case of a baby who immediately after birth presented with pronounced truncal hypotonia, proximal muscle weakness and feeding difficulties. Single fibre electromyography showed neuromuscular transmission failure and salbutamol and ephedrine treatment improved both muscle weakness and neuromuscular transmission. Genetic analysis revealed a likely pathogenic variant c.1040del, p.(Gly347Valfs*27) in exon 2 and a variant of uncertain significance, c.239G>A, p.(Gly80Asp) in exon 1 of the ALG2 gene. Western blot in whole cell lysates of HEK293 cells transfected with p.Gly80Asp, or p.Gly347Valfs*27 expression constructs indicated that p.Gly347Valfs*27 is likely a null allele and p.Gly80Asp is pathogenic through marked reduction of ALG2 expression. This case highlights the utility of functional studies in clarifying variants of unknown significance, in suspected cases of CMS.
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13
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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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14
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Mergnac JP, Wiedemann A, Chery C, Ravel JM, Namour F, Guéant JL, Feillet F, Oussalah A. Diagnostic yield of clinical exome sequencing as a first-tier genetic test for the diagnosis of genetic disorders in pediatric patients: results from a referral center study. Hum Genet 2021; 141:1269-1278. [PMID: 34495415 DOI: 10.1007/s00439-021-02358-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 08/28/2021] [Indexed: 12/29/2022]
Abstract
The emergence of next-generation sequencing enabled a cost-effective and straightforward diagnostic approach to genetic disorders using clinical exome sequencing (CES) panels. We performed a retrospective observational study to assess the diagnostic yield of CES as a first-tier genetic test in 128 consecutive pediatric patients addressed to a referral center in the North-East of France for a suspected genetic disorder, mainly an inborn error of metabolism between January 2016 and August 2020. CES was performed using the TruSight One (4811 genes) or the TruSight One expanded (6699 genes) panel on an Illumina sequencing platform. The median age was 6.5 years (IQR 2.0-12.0) with 43% of males (55/128), and the median disease duration was 7 months (IQR 1-47). In the whole analysis, the CES diagnostic yield was 55% (70/128). The median test-to-report time was 5 months (IQR 4-7). According to CES indications, the CES diagnostic yields were 81% (21/26) for hyperlipidemia, 75% (6/8) for osteogenesis imperfecta, 64% (25/39) for metabolic disorders, 39% (10/26) for neurological disorders, and 28% (8/29) for the subgroup of patients with miscellaneous conditions. Our results demonstrate the usefulness of a CES-based diagnosis as a first-tier genetic test to establish a molecular diagnosis in pediatric patients with a suspected genetic disorder with a median test-to-report time of 5 months. It highlights the importance of a close interaction between the pediatrician with expertise in genetic disorders and the molecular medicine physician to optimize both CES indication and interpretation. Diagnostic yield of clinical exome sequencing (CES) as a first-tier genetic test for diagnosing genetic disorders in 128 consecutive pediatric patients referred to a reference center in the North-East of France for a suspected genetic disorder, mainly an inborn error of metabolism between January 2016 and August 2020. The CES diagnostic yields are reported in the whole population and patients' subgroups (hyperlipidemia, osteogenesis imperfecta, metabolic diseases, neurological disorders, miscellaneous conditions) (Icons made by Flaticon, flaticon.com; CC-BY-3.0).
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Affiliation(s)
- Jean-Philippe Mergnac
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France.,Department of Pediatrics, University Hospital of Nancy, 54000, Nancy, France
| | - Arnaud Wiedemann
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France.,Pediatric Intensive Care Unit, University Hospital of Nancy, 54000, Nancy, France.,Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000, Nancy, France
| | - Céline Chery
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France.,Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000, Nancy, France.,Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, and Nutrition, University Hospital of Nancy, 54000, Nancy, France
| | - Jean-Marie Ravel
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France
| | - Farès Namour
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France.,Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000, Nancy, France.,Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, and Nutrition, University Hospital of Nancy, 54000, Nancy, France
| | - Jean-Louis Guéant
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France.,Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000, Nancy, France.,Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, and Nutrition, University Hospital of Nancy, 54000, Nancy, France
| | - François Feillet
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France.,Department of Pediatrics, University Hospital of Nancy, 54000, Nancy, France.,Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000, Nancy, France
| | - Abderrahim Oussalah
- Reference Center for Inborn Errors of Metabolism (ORPHA67872), University Hospital of Nancy, 54000, Nancy, France. .,Nutrition, Genetics, and Environmental Risk Exposure (NGERE), Faculty of Medicine of Nancy, University of Lorraine, INSERM UMR_S 1256, 54000, Nancy, France. .,Department of Molecular Medicine, Division of Biochemistry, Molecular Biology, and Nutrition, University Hospital of Nancy, 54000, Nancy, France.
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15
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Gücüm S, Sakson R, Hoffmann M, Grote V, Becker C, Pakari K, Beedgen L, Thiel C, Rapp E, Ruppert T, Thumberger T, Wittbrodt J. A patient-based medaka alg2 mutant as a model for hypo-N-glycosylation. Development 2021; 148:269015. [PMID: 34106226 PMCID: PMC8217707 DOI: 10.1242/dev.199385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/04/2021] [Indexed: 11/20/2022]
Abstract
Defects in the evolutionarily conserved protein-glycosylation machinery during embryonic development are often fatal. Consequently, congenital disorders of glycosylation (CDG) in human are rare. We modelled a putative hypomorphic mutation described in an alpha-1,3/1,6-mannosyltransferase (ALG2) index patient (ALG2-CDG) to address the developmental consequences in the teleost medaka (Oryzias latipes). We observed specific, multisystemic, late-onset phenotypes, closely resembling the patient's syndrome, prominently in the facial skeleton and in neuronal tissue. Molecularly, we detected reduced levels of N-glycans in medaka and in the patient's fibroblasts. This hypo-N-glycosylation prominently affected protein abundance. Proteins of the basic glycosylation and glycoprotein-processing machinery were over-represented in a compensatory response, highlighting the regulatory topology of the network. Proteins of the retinal phototransduction machinery, conversely, were massively under-represented in the alg2 model. These deficiencies relate to a specific failure to maintain rod photoreceptors, resulting in retinitis pigmentosa characterized by the progressive loss of these photoreceptors. Our work has explored only the tip of the iceberg of N-glycosylation-sensitive proteins, the function of which specifically impacts on cells, tissues and organs. Taking advantage of the well-described human mutation has allowed the complex interplay of N-glycosylated proteins and their contribution to development and disease to be addressed.
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Affiliation(s)
- Sevinç Gücüm
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany.,HBIGS, Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany
| | - Roman Sakson
- HBIGS, Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany.,Core facility for Mass Spectrometry and Proteomics, Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Marcus Hoffmann
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany
| | - Valerian Grote
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany
| | - Clara Becker
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Kaisa Pakari
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Lars Beedgen
- Center for Child and Adolescent Medicine, Department Pediatrics I, Heidelberg University, 69120 Heidelberg, Germany
| | - Christian Thiel
- Center for Child and Adolescent Medicine, Department Pediatrics I, Heidelberg University, 69120 Heidelberg, Germany
| | - Erdmann Rapp
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany.,glyXera GmbH, 39120 Magdeburg, Germany
| | - Thomas Ruppert
- Core facility for Mass Spectrometry and Proteomics, Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Thomas Thumberger
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
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16
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Palombo F, Piccolo B, Saccani E, Fiorini C, Capristo M, Caporali L, Pisani F, Carelli V. A novel ALG14 missense variant in an alive child with myopathy, epilepsy, and progressive cerebral atrophy. Am J Med Genet A 2021; 185:1918-1921. [PMID: 33751823 DOI: 10.1002/ajmg.a.62153] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 02/15/2021] [Accepted: 02/20/2021] [Indexed: 11/08/2022]
Affiliation(s)
- Flavia Palombo
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Benedetta Piccolo
- Child Neuropsychiatric Unit, Mother and Child Department, AOU di Parma, Parma, Italy
| | - Elena Saccani
- Dipartimento di Medicina Generale e Specialistica, U.O Neurologia, AOU di Parma, Parma, Italy
| | - Claudio Fiorini
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Mariantonietta Capristo
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Leonardo Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy
| | - Francesco Pisani
- Child Neuropsychiatric Unit, Medicine and Surgery Department, Neuroscience Section, University of Parma, Parma, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna, Italy.,Department of Biomedical and NeuroMotor Sciences (DIBINEM), University of Bologna, Bologna, Italy
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17
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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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18
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Paprocka J, Jezela-Stanek A, Tylki-Szymańska A, Grunewald S. Congenital Disorders of Glycosylation from a Neurological Perspective. Brain Sci 2021; 11:brainsci11010088. [PMID: 33440761 PMCID: PMC7827962 DOI: 10.3390/brainsci11010088] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2020] [Revised: 01/01/2021] [Accepted: 01/04/2021] [Indexed: 12/11/2022] Open
Abstract
Most plasma proteins, cell membrane proteins and other proteins are glycoproteins with sugar chains attached to the polypeptide-glycans. Glycosylation is the main element of the post-translational transformation of most human proteins. Since glycosylation processes are necessary for many different biological processes, patients present a diverse spectrum of phenotypes and severity of symptoms. The most frequently observed neurological symptoms in congenital disorders of glycosylation (CDG) are: epilepsy, intellectual disability, myopathies, neuropathies and stroke-like episodes. Epilepsy is seen in many CDG subtypes and particularly present in the case of mutations in the following genes: ALG13, DOLK, DPAGT1, SLC35A2, ST3GAL3, PIGA, PIGW, ST3GAL5. On brain neuroimaging, atrophic changes of the cerebellum and cerebrum are frequently seen. Brain malformations particularly in the group of dystroglycanopathies are reported. Despite the growing number of CDG patients in the world and often neurological symptoms dominating in the clinical picture, the number of performed screening tests eg transferrin isoforms is systematically decreasing as broadened genetic testing is recently more favored. The aim of the review is the summary of selected neurological symptoms in CDG described in the literature in one paper. It is especially important for pediatric neurologists not experienced in the field of metabolic medicine. It may help to facilitate the diagnosis of this expanding group of disorders. Biochemically, this paper focuses on protein glycosylation abnormalities.
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Affiliation(s)
- Justyna Paprocka
- Department of Pediatric Neurology, Faculty of Medical Science in Katowice, Medical University of Silesia, 40-752 Katowice, Poland
- Correspondence: ; Tel.: +48-606-415-888
| | - Aleksandra Jezela-Stanek
- Department of Genetics and Clinical Immunology, National Institute of Tuberculosis and Lung Diseases, 01-138 Warsaw, Poland;
| | - Anna Tylki-Szymańska
- Department of Pediatrics, Nutrition and Metabolic Diseases, The Children’s Memorial Health Institute, W 04-730 Warsaw, Poland;
| | - Stephanie Grunewald
- NIHR Biomedical Research Center (BRC), Metabolic Unit, Great Ormond Street Hospital and Institute of Child Health, University College London, London SE1 9RT, UK;
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19
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Spendiff S, Howarth R, McMacken G, Davey T, Quinlan K, O'Connor E, Slater C, Hettwer S, Mäder A, Roos A, Horvath R, Lochmüller H. Modulation of the Acetylcholine Receptor Clustering Pathway Improves Neuromuscular Junction Structure and Muscle Strength in a Mouse Model of Congenital Myasthenic Syndrome. Front Mol Neurosci 2021; 13:594220. [PMID: 33390901 PMCID: PMC7773664 DOI: 10.3389/fnmol.2020.594220] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/24/2020] [Indexed: 11/16/2022] Open
Abstract
Introduction: Congenital myasthenic syndromes (CMS) are a diverse group of inherited neuromuscular disorders characterized by a failure of synaptic transmission at the neuromuscular junction (NMJ). CMS often present early with fatigable weakness and can be fatal through respiratory complications. The AGRN gene is one of over 30 genes known to harbor mutations causative for CMS. In this study, we aimed to determine if a compound (NT1654), developed to stimulate the acetylcholine receptor (AChR) clustering pathway, would benefit a mouse model of CMS caused by a loss-of-function mutation in Agrn (Agrnnmf380 mouse). Methods:Agrnnmf380 mice received an injection of either NT1654 or vehicle compound daily, with wild-type litter mates used for comparison. Animals were weighed daily and underwent grip strength assessments. After 30 days of treatment animals were sacrificed, and muscles collected. Investigations into NMJ and muscle morphology were performed on collected tissue. Results: While minimal improvements in NMJ ultrastructure were observed with electron microscopy, gross NMJ structure analysis using fluorescent labelling and confocal microscopy revealed extensive postsynaptic improvements in Agrnnmf380 mice with NT1654 administration, with variables frequently returning to wild type levels. An improvement in muscle weight and myofiber characteristics helped increase forelimb grip strength and body weight. Conclusions: We conclude that NT1654 restores NMJ postsynaptic structure and improves muscle strength through normalization of muscle fiber composition and the prevention of atrophy. We hypothesize this occurs through the AChR clustering pathway in Agrnnmf380 mice. Future studies should investigate if this may represent a viable treatment option for patients with CMS, especially those with mutations in proteins of the AChR clustering pathway.
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Affiliation(s)
- Sally Spendiff
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Rachel Howarth
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Grace McMacken
- Department of Neurosciences, Royal Victoria Hospital, Belfast, United Kingdom
| | - Tracey Davey
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Kaitlyn Quinlan
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada
| | - Emily O'Connor
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Brain and Mind Research Institute, University of Ottawa, Ottawa, ON, Canada
| | - Clarke Slater
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, United Kingdom
| | | | | | - Andreas Roos
- Children's Hospital of Eastern Ontario Research Institute, Ottawa, ON, Canada.,Department of Paediatric Neurology, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Rita Horvath
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, United Kingdom
| | - 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 Neuropediatrics and Muscle Disorders, Medical Center - University of Freiburg, Freiburg, Germany.,Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
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20
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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: 73] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [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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21
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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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22
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Ng BG, Eklund EA, Shiryaev SA, Dong YY, Abbott MA, Asteggiano C, Bamshad MJ, Barr E, Bernstein JA, Chelakkadan S, Christodoulou J, Chung WK, Ciliberto MA, Cousin J, Gardiner F, Ghosh S, Graf WD, Grunewald S, Hammond K, Hauser NS, Hoganson GE, Houck KM, Kohler JN, Morava E, Larson AA, Liu P, Madathil S, McCormack C, Meeks NJ, Miller R, Monaghan KG, Nickerson DA, Palculict TB, Papazoglu GM, Pletcher BA, Scheffer IE, Schenone AB, Schnur RE, Si Y, Rowe LJ, Serrano Russi AH, Russo RS, Thabet F, Tuite A, Mercedes Villanueva M, Wang RY, Webster RI, Wilson D, Zalan A, Wolfe LA, Rosenfeld JA, Rhodes L, Freeze HH. Predominant and novel de novo variants in 29 individuals with ALG13 deficiency: Clinical description, biomarker status, biochemical analysis, and treatment suggestions. J Inherit Metab Dis 2020; 43:1333-1348. [PMID: 32681751 PMCID: PMC7722193 DOI: 10.1002/jimd.12290] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/03/2020] [Accepted: 07/09/2020] [Indexed: 12/14/2022]
Abstract
Asparagine-linked glycosylation 13 homolog (ALG13) encodes a nonredundant, highly conserved, X-linked uridine diphosphate (UDP)-N-acetylglucosaminyltransferase required for the synthesis of lipid linked oligosaccharide precursor and proper N-linked glycosylation. De novo variants in ALG13 underlie a form of early infantile epileptic encephalopathy known as EIEE36, but given its essential role in glycosylation, it is also considered a congenital disorder of glycosylation (CDG), ALG13-CDG. Twenty-four previously reported ALG13-CDG cases had de novo variants, but surprisingly, unlike most forms of CDG, ALG13-CDG did not show the anticipated glycosylation defects, typically detected by altered transferrin glycosylation. Structural homology modeling of two recurrent de novo variants, p.A81T and p.N107S, suggests both are likely to impact the function of ALG13. Using a corresponding ALG13-deficient yeast strain, we show that expressing yeast ALG13 with either of the highly conserved hotspot variants rescues the observed growth defect, but not its glycosylation abnormality. We present molecular and clinical data on 29 previously unreported individuals with de novo variants in ALG13. This more than doubles the number of known cases. A key finding is that a vast majority of the individuals presents with West syndrome, a feature shared with other CDG types. Among these, the initial epileptic spasms best responded to adrenocorticotropic hormone or prednisolone, while clobazam and felbamate showed promise for continued epilepsy treatment. A ketogenic diet seems to play an important role in the treatment of these individuals.
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Affiliation(s)
- Bobby G. Ng
- Human Genetics Program, Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Erik A. Eklund
- Human Genetics Program, Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
- Department of Clinical Sciences, Lund, Pediatrics, Lund University, Lund, Sweden
| | - Sergey A. Shiryaev
- Human Genetics Program, Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - Yin Y. Dong
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Mary-Alice Abbott
- Department of Pediatrics, Baystate Children’s Hospital, University of Massachusetts Medical School - Baystate, Springfield, Massachusetts
| | - Carla Asteggiano
- CEMECO—CONICET, Children Hospital, School of Medicine, National University of Cordoba, Cordoba, Argentina
- Chair of Pharmacology, Catholic University of Cordoba, Cordoba, Argentina
| | - Michael J. Bamshad
- Department of Pediatrics, University of Washington, Seattle, Washington
- Department of Genome Sciences, University of Washington, Seattle, Washington
| | - Eileen Barr
- Department of Human Genetics, Emory University, Atlanta, Georgia
| | - Jonathan A. Bernstein
- Stanford University School of Medicine, Stanford, California
- Stanford Center for Undiagnosed Diseases, Stanford University, Stanford, California
| | | | - John Christodoulou
- Brain and Mitochondrial Research Group, Murdoch Children’s Research Institute, Royal Children’s Hospital, Melbourne, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, Australia
- Discipline of Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, Australia
| | - Wendy K. Chung
- Department of Pediatrics, Columbia University, New York, New York
- Department of Medicine, Columbia University, New York, New York
| | - Michael A. Ciliberto
- Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Janice Cousin
- Section of Human Biochemical Genetics, National Human Genome Research Institute, Bethesda, Maryland
| | - Fiona Gardiner
- University of Melbourne, Austin Health, Melbourne, Australia
| | - Suman Ghosh
- Department of Pediatrics Division of Pediatric Neurology, University of Florida College of Medicine, Gainesville, Florida
| | - William D. Graf
- Division of Pediatric Neurology, Department of Pediatrics, Connecticut Children’s; University of Connecticut, Farmington, Connecticut
| | - Stephanie Grunewald
- Metabolic Medicine Department, Great Ormond Street Hospital, Institute of Child Health University College London, NIHR Biomedical Research Center, London, UK
| | - Katherine Hammond
- Division of Pediatric Neurology, Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Natalie S. Hauser
- Inova Translational Medicine Institute Division of Medical Genomics Inova Fairfax Hospital Falls Church, Virginia
| | - George E. Hoganson
- Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois
| | - Kimberly M. Houck
- Department of Pediatrics, Section of Neurology and Developmental Neuroscience, Baylor College of Medicine, Houston, Texas
| | - Jennefer N. Kohler
- Stanford University School of Medicine, Stanford, California
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Eva Morava
- Department of Clinical Genomics, Mayo Clinic, Rochester, Minnesota
| | - Austin A. Larson
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics Laboratories, Houston, Texas
| | - Sujana Madathil
- Department of Pediatrics, University of Iowa Hospitals and Clinics, Iowa City, Iowa
| | - Colleen McCormack
- Stanford University School of Medicine, Stanford, California
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Naomi J.L. Meeks
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Rebecca Miller
- Inova Translational Medicine Institute Division of Medical Genomics Inova Fairfax Hospital Falls Church, Virginia
| | | | | | | | - Gabriela Magali Papazoglu
- CEMECO—CONICET, Children Hospital, School of Medicine, National University of Cordoba, Cordoba, Argentina
| | - Beth A. Pletcher
- Department of Pediatrics, Rutgers New Jersey Medical School, Newark, New Jersey
| | - Ingrid E. Scheffer
- University of Melbourne, Austin Health, Melbourne, Australia
- University of Melbourne, Royal Children’s Hospital, Florey and Murdoch Institutes, Melbourne, Australia
| | | | | | - Yue Si
- GeneDx, Inc. Laboratory, Gaithersburg, Maryland
| | - Leah J. Rowe
- Section of Clinical Genetics and Metabolism, Department of Pediatrics, University of Colorado, Anschutz Medical Campus, Aurora, Colorado
| | - Alvaro H. Serrano Russi
- Division of Medical Genetics Children’s Hospital Los Angeles, University of Southern California, Los Angeles, California
- Keck School of Medicine, University of Southern California, Los Angeles, California
| | | | | | - Allysa Tuite
- Department of Pediatrics, Rutgers New Jersey Medical School, Newark, New Jersey
| | | | - Raymond Y. Wang
- Division of Metabolic Disorders, Children’s Hospital of Orange County, Orange, California
- Department of Pediatrics, University of California-Irvine, Orange, California
| | - Richard I. Webster
- T.Y. Nelson Department of Neurology and Neurosurgery, The Children’s Hospital, Westmead, Australia
- Kids Neuroscience Centre, The Children’s Hospital, Westmead, Australia
| | - Dorcas Wilson
- Netcare Sunninghill Hospital, Sandton, South Africa
- Nelson Mandela Children’s Hospital, Johannesburg, South Africa
| | - Alice Zalan
- Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois
| | | | - Lynne A. Wolfe
- Undiagnosed Diseases Program, Common Fund, National Institutes of Health, Bethesda, Maryland
| | - Jill A. Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
- Baylor Genetics Laboratories, Houston, Texas
| | | | - Hudson H. Freeze
- Human Genetics Program, Sanford Children’s Health Research Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
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23
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Bogenschutz EL, Fox ZD, Farrell A, Wynn J, Moore B, Yu L, Aspelund G, Marth G, Yandell M, Shen Y, Chung WK, Kardon G. Deep whole-genome sequencing of multiple proband tissues and parental blood reveals the complex genetic etiology of congenital diaphragmatic hernias. HGG ADVANCES 2020; 1:100008. [PMID: 33263113 PMCID: PMC7703690 DOI: 10.1016/j.xhgg.2020.100008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 08/07/2020] [Indexed: 12/17/2022] Open
Abstract
The diaphragm is critical for respiration and separation of the thoracic and abdominal cavities, and defects in diaphragm development are the cause of congenital diaphragmatic hernias (CDH), a common and often lethal birth defect. The genetic etiology of CDH is complex. Single-nucleotide variants (SNVs), insertions/deletions (indels), and structural variants (SVs) in more than 150 genes have been associated with CDH, although few genes are recurrently mutated in multiple individuals and mutated genes are incompletely penetrant. This suggests that multiple genetic variants in combination, other not-yet-investigated classes of variants, and/or nongenetic factors contribute to CDH etiology. However, no studies have comprehensively investigated in affected individuals the contribution of all possible classes of variants throughout the genome to CDH etiology. In our study, we used a unique cohort of four individuals with isolated CDH with samples from blood, skin, and diaphragm connective tissue and parental blood and deep whole-genome sequencing to assess germline and somatic de novo and inherited SNVs, indels, and SVs. In each individual we found a different mutational landscape that included germline de novo and inherited SNVs and indels in multiple genes. We also found in two individuals a 343 bp deletion interrupting an annotated enhancer of the CDH-associated gene GATA4, and we hypothesize that this common SV (found in 1%-2% of the population) acts as a sensitizing allele for CDH. Overall, our comprehensive reconstruction of the genetic architecture of four CDH individuals demonstrates that the etiology of CDH is heterogeneous and multifactorial.
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Affiliation(s)
- Eric L. Bogenschutz
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Zac D. Fox
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Andrew Farrell
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- USTAR Center for Genetic Discovery, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Julia Wynn
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Barry Moore
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- USTAR Center for Genetic Discovery, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Lan Yu
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Gudrun Aspelund
- Department of Surgery, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Gabor Marth
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- USTAR Center for Genetic Discovery, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Mark Yandell
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- USTAR Center for Genetic Discovery, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Yufeng Shen
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Biomedical Informatics, Columbia University Irving Medical Center, New York, NY 10032, USA
- JP Sulzberger Columbia Genome Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Wendy K. Chung
- Department of Pediatrics, Columbia University Irving Medical Center, New York, NY 10032, USA
- Department of Medicine, Columbia University Irving Medical Center, New York, NY 10032, USA
- Herbert Irving Comprehensive Cancer Center, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Gabrielle Kardon
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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Caenorhabditis elegans algn-2 Is Critical for Longevity Conferred by Enhanced Nonsense-Mediated mRNA Decay. iScience 2020; 23:101713. [PMID: 33225240 PMCID: PMC7662852 DOI: 10.1016/j.isci.2020.101713] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/10/2020] [Accepted: 10/16/2020] [Indexed: 11/23/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a biological surveillance mechanism that eliminates mRNA transcripts with premature termination codons. In Caenorhabditis elegans, NMD contributes to longevity by enhancing RNA quality. Here, we aimed at identifying NMD-modulating factors that are crucial for longevity in C. elegans by performing genetic screens. We showed that knocking down each of algn-2/asparagine-linked glycosylation protein, zip-1/bZIP transcription factor, and C44B11.1/FAS apoptotic inhibitory molecule increased the transcript levels of NMD targets. Among these, algn-2 exhibited an age-dependent decrease in its expression and was required for maintaining normal lifespan and for longevity caused by various genetic interventions. We further demonstrated that upregulation of ALGN-2 by inhibition of daf-2/insulin/IGF-1 receptor contributed to longevity in an NMD-dependent manner. Thus, algn-2, a positive regulator of NMD, plays a crucial role in longevity in C. elegans, likely by enhancing RNA surveillance. Our study will help understand how NMD-mediated mRNA quality control extends animal lifespan. C. elegans algn-2 is a positive regulator of nonsense-mediated mRNA decay (NMD) algn-2 is downregulated during aging and contributes to maintaining normal lifespan algn-2 is required for longevity caused by various genetic interventions Upregulation of ALGN-2 by inhibition of daf-2 promotes longevity via increasing NMD
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25
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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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26
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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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27
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Szelinger S, Krate J, Ramsey K, Strom SP, Shieh PB, Lee H, Belnap N, Balak C, Siniard AL, Russell M, Richholt R, Both MD, Claasen AM, Schrauwen I, Nelson SF, Huentelman MJ, Craig DW, Yang SP, Moore SA, Sivakumar K, Narayanan V, Rangasamy S. Congenital myasthenic syndrome caused by a frameshift insertion mutation in GFPT1. NEUROLOGY-GENETICS 2020; 6:e468. [PMID: 32754643 PMCID: PMC7357421 DOI: 10.1212/nxg.0000000000000468] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 05/26/2020] [Indexed: 12/17/2022]
Abstract
Objective Description of a new variant of the glutamine-fructose-6-phosphate transaminase 1 (GFPT1) gene causing congenital myasthenic syndrome (CMS) in 3 children from 2 unrelated families. Methods Muscle biopsies, EMG, and whole-exome sequencing were performed. Results All 3 patients presented with congenital hypotonia, muscle weakness, respiratory insufficiency, head lag, areflexia, and gastrointestinal dysfunction. Genetic analysis identified a homozygous frameshift insertion in the GFPT1 gene (NM_001244710.1: c.686dupC; p.Arg230Ter) that was shared by all 3 patients. In one of the patients, inheritance of the variant was through uniparental disomy (UPD) with maternal origin. Repetitive nerve stimulation and single-fiber EMG was consistent with the clinical diagnosis of CMS with a postjunctional defect. Ultrastructural evaluation of the muscle biopsy from one of the patients showed extremely attenuated postsynaptic folds at neuromuscular junctions and extensive autophagic vacuolar pathology. Conclusions These results expand on the spectrum of known loss-of-function GFPT1 mutations in CMS12 and in one family demonstrate a novel mode of inheritance due to UPD.
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Affiliation(s)
- Szabolcs Szelinger
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Jonida Krate
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Keri Ramsey
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Samuel P Strom
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Perry B Shieh
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Hane Lee
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Newell Belnap
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Chris Balak
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Ashley L Siniard
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Megan Russell
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Ryan Richholt
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Matt De Both
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Ana M Claasen
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Isabelle Schrauwen
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Stanley F Nelson
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Matthew J Huentelman
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - David W Craig
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Samuel P Yang
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Steven A Moore
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Kumaraswamy Sivakumar
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Vinodh Narayanan
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
| | - Sampathkumar Rangasamy
- theNeurogenomics Division (S.S., J.K., K.R., N.B., C.B., A.L.S., M.R., R.R., M.D.B., A.M.C., M.J.H, V.N., S.R.), Translational Genomics Research Institute, Center for Rare Childhood Disorders, Phoenix, AZ; Fulgent Genetics (S.P.S.), Temple City, CA; Department of Neurology (P.B.S.), University of California Los Angeles; David Geffen School of Medicine (P.B.S.), Los Angeles; Department of Pathology and Laboratory Medicine (H.L., S.F.N.), University of California, Los Angeles; Department of Human Genetics (H.L., S.F.N.), David Geffen School of Medicine; Department of Neurology (I.S.), Columbia University, Center for Statistical Genetics, New York; Department of Translational Genomics (D.W.C.), University of Southern California, Los Angeles; Providence Sacred Heart Medical Center and Children's Hospital (S.P.Y.), Spokane, WA; Department of Pathology (S.A.M), University of Iowa, Carver College of Medicine; and Neuromuscular Clinic and Research Center (K.S.), Phoenix, AZ
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Xiao T, Wu LW. [Advances in the diagnosis and treatment of congenital myasthenic syndrome]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2020; 22:672-676. [PMID: 32571471 PMCID: PMC7390217 DOI: 10.7499/j.issn.1008-8830.1912095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/24/2020] [Indexed: 06/11/2023]
Abstract
Congenital myasthenic syndrome (CMS) is a group of clinical and genetic heterogeneous diseases caused by impaired neuromuscular transmission due to genetic defects. At present, it has been reported that more than 30 genes can cause CMS. All CMS subtypes have the clinical features of fatigue and muscle weakness, but age of onset, symptoms, and treatment response vary with the molecular mechanisms underlying genetic defects. Pharmacotherapy and symptomatic/supportive treatment are the main methods for the treatment of CMS, and antisense oligonucleotide technology has been proven to be beneficial for CHRNA 1-related CMS in animals. Since CMS is a group of increasingly recognized clinical and genetic heterogeneous diseases, an understanding of the latest knowledge and research advances in its clinical features, genetic research, and treatment helps to give early diagnosis and treatment as well as gain a deeper understanding of the pathogenesis of CMS, so as to make new breakthroughs in the treatment of CMS.
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Affiliation(s)
- Ting Xiao
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha 410008, China.
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Xiao T, Wu LW. [Advances in the diagnosis and treatment of congenital myasthenic syndrome]. ZHONGGUO DANG DAI ER KE ZA ZHI = CHINESE JOURNAL OF CONTEMPORARY PEDIATRICS 2020; 22:672-676. [PMID: 32571471 PMCID: PMC7390217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/24/2020] [Indexed: 11/12/2023]
Abstract
Congenital myasthenic syndrome (CMS) is a group of clinical and genetic heterogeneous diseases caused by impaired neuromuscular transmission due to genetic defects. At present, it has been reported that more than 30 genes can cause CMS. All CMS subtypes have the clinical features of fatigue and muscle weakness, but age of onset, symptoms, and treatment response vary with the molecular mechanisms underlying genetic defects. Pharmacotherapy and symptomatic/supportive treatment are the main methods for the treatment of CMS, and antisense oligonucleotide technology has been proven to be beneficial for CHRNA 1-related CMS in animals. Since CMS is a group of increasingly recognized clinical and genetic heterogeneous diseases, an understanding of the latest knowledge and research advances in its clinical features, genetic research, and treatment helps to give early diagnosis and treatment as well as gain a deeper understanding of the pathogenesis of CMS, so as to make new breakthroughs in the treatment of CMS.
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Affiliation(s)
- Ting Xiao
- Department of Pediatrics, Xiangya Hospital, Central South University, Changsha 410008, China.
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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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Rodríguez Cruz PM, Cossins J, Estephan EDP, Munell F, Selby K, Hirano M, Maroofin R, Mehrjardi MYV, Chow G, Carr A, Manzur A, Robb S, Munot P, Wei Liu W, Banka S, Fraser H, De Goede C, Zanoteli E, Conti Reed U, Sage A, Gratacos M, Macaya A, Dusl M, Senderek J, Töpf A, Hofer M, Knight R, Ramdas S, Jayawant S, Lochmüller H, Palace J, Beeson D. The clinical spectrum of the congenital myasthenic syndrome resulting from COL13A1 mutations. Brain 2020; 142:1547-1560. [PMID: 31081514 PMCID: PMC6752227 DOI: 10.1093/brain/awz107] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/08/2019] [Accepted: 02/22/2019] [Indexed: 02/02/2023] Open
Abstract
Next generation sequencing techniques were recently used to show mutations in COL13A1 cause synaptic basal lamina-associated congenital myasthenic syndrome type 19. Animal studies showed COL13A1, a synaptic extracellular-matrix protein, is involved in the formation and maintenance of the neuromuscular synapse that appears independent of the Agrin-LRP4-MuSK-DOK7 acetylcholine receptor clustering pathway. Here, we report the phenotypic spectrum of 16 patients from 11 kinships harbouring homozygous or heteroallelic mutations in COL13A1. Clinical presentation was mostly at birth with hypotonia and breathing and feeding difficulties often requiring ventilation and artificial feeding. Respiratory crisis related to recurrent apnoeas, sometimes triggered by chest infections, were common early in life but resolved over time. The predominant pattern of muscle weakness included bilateral ptosis (non-fatigable in adulthood), myopathic facies and marked axial weakness, especially of neck flexion, while limb muscles were less involved. Other features included facial dysmorphism, skeletal abnormalities and mild learning difficulties. All patients tested had results consistent with abnormal neuromuscular transmission. Muscle biopsies were within normal limits or showed non-specific changes. Muscle MRI and serum creatine kinase levels were normal. In keeping with COL13A1 mutations affecting both synaptic structure and presynaptic function, treatment with 3,4-diaminopyridine and salbutamol resulted in motor and respiratory function improvement. In non-treated cases, disease severity and muscle strength improved gradually over time and several adults recovered normal muscle strength in the limbs. In summary, patients with COL13A1 mutations present mostly with severe early-onset myasthenic syndrome with feeding and breathing difficulties. Axial weakness is greater than limb weakness. Disease course improves gradually over time, which could be consistent with the less prominent role of COL13A1 once the neuromuscular junction is mature. This report emphasizes the role of collagens at the human muscle endplate and should facilitate the recognition of this disorder, which can benefit from pharmacological treatment.
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Affiliation(s)
- Pedro M Rodríguez Cruz
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK.,Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Judith Cossins
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Eduardo de Paula Estephan
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Francina Munell
- Neuromuscular disorders Group, Child Neurology Unit, Hospital Universitari Vall d'Hebron, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - Kathryn Selby
- University of British Columbia, Vancouver, British Columbia, Canada
| | - Michio Hirano
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY, USA
| | - Reza Maroofin
- Molecular and Clinical Sciences Institute, St. George's, University of London, Cranmer Terrace, London, UK
| | | | - Gabriel Chow
- Department of Paediatric Neurology, Nottingham City Hospital, Nottingham University Hospitals NHS Trust, Hucknall Road, Nottingham, UK
| | - Aisling Carr
- MRC Centre for Neuromuscular Diseases, National Hospital for Neurology and Neurosurgery, London, UK
| | - Adnan Manzur
- Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Stephanie Robb
- Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Pinki Munot
- Dubowitz Neuromuscular Centre and MRC Centre for Neuromuscular Diseases, UCL Great Ormond Street Institute of Child Health, London, UK
| | - Wei Wei Liu
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Siddharth Banka
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK
| | - Harry Fraser
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester, UK
| | | | - Edmar Zanoteli
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Umbertina Conti Reed
- Departamento de Neurologia, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, Brazil
| | - Abigail Sage
- Department of Neurology, H. Houston Merritt Neuromuscular Research Center, Columbia University Medical Center, New York, NY, USA
| | - Margarida Gratacos
- Department of Clinical Neurophysiology, Hospital Universitari Vall d'Hebron, Barcelona Spain
| | - Alfons Macaya
- Neuromuscular disorders Group, Child Neurology Unit, Hospital Universitari Vall d'Hebron, Vall d'Hebron Research Institute (VHIR), Barcelona, Spain
| | - Marina Dusl
- Friedrich-Baur-Institute at the Department of Neurology, University Hospital LMU Munich, Munich, Germany
| | - Jan Senderek
- Friedrich-Baur-Institute at the Department of Neurology, University Hospital LMU Munich, Munich, Germany
| | - Ana Töpf
- Institute of Genetic Medicine, Central Parkway, Newcastle upon Tyne, UK
| | - Monika Hofer
- Department of Neuropathology, John Radcliffe Hospital NHS Foundation Trust, Oxford, UK
| | - Ravi Knight
- Department of Clinical Neurophysiology, John Radcliffe Hospital NHS Foundation Trust, Oxford, UK
| | - Sithara Ramdas
- Department of Paediatric Neurology, John Radcliffe Hospital NHS Foundation Trust, Oxford, UK
| | - Sandeep Jayawant
- Department of Paediatric Neurology, John Radcliffe Hospital NHS Foundation Trust, Oxford, UK
| | - Hans Lochmüller
- Department of Neuropediatrics and Muscle Disorders, Medical Center-University of Freiburg, Faculty of Medicine, Freiburg, Germany.,Centro Nacional de Análisis Genómico (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain.,Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Canada.,Division of Neurology, Department of Medicine, The Ottawa Hospital, Ottawa, Canada
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - David Beeson
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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Pascoal C, Francisco R, Ferro T, Dos Reis Ferreira V, Jaeken J, Videira PA. CDG and immune response: From bedside to bench and back. J Inherit Metab Dis 2020; 43:90-124. [PMID: 31095764 DOI: 10.1002/jimd.12126] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/13/2019] [Accepted: 05/15/2019] [Indexed: 12/20/2022]
Abstract
Glycosylation is an essential biological process that adds structural and functional diversity to cells and molecules, participating in physiological processes such as immunity. The immune response is driven and modulated by protein-attached glycans that mediate cell-cell interactions, pathogen recognition and cell activation. Therefore, abnormal glycosylation can be associated with deranged immune responses. Within human diseases presenting immunological defects are congenital disorders of glycosylation (CDG), a family of around 130 rare and complex genetic diseases. In this review, we have identified 23 CDG with immunological involvement, characterized by an increased propensity to-often life-threatening-infection. Inflammatory and autoimmune complications were found in 7 CDG types. CDG natural history(ies) and the mechanisms behind the immunological anomalies are still poorly understood. However, in some cases, alterations in pathogen recognition and intracellular signaling (eg, TGF-β1, NFAT, and NF-κB) have been suggested. Targeted therapies to restore immune defects are only available for PGM3-CDG and SLC35C1-CDG. Fostering research on glycoimmunology may elucidate the involved pathophysiological mechanisms and open new therapeutic avenues, thus improving CDG patients' quality of life.
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Affiliation(s)
- Carlota Pascoal
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Rita Francisco
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Tiago Ferro
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Vanessa Dos Reis Ferreira
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
| | - Jaak Jaeken
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- Center for Metabolic Diseases, Department of Development and Regeneration, UZ and KU Leuven, Leuven, Belgium
| | - Paula A Videira
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
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33
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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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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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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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36
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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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Asteggiano CG, Papazoglu M, Bistué Millón MB, Peralta MF, Azar NB, Spécola NS, Guelbert N, Suldrup NS, Pereyra M, Dodelson de Kremer R. Ten years of screening for congenital disorders of glycosylation in Argentina: case studies and pitfalls. Pediatr Res 2018; 84:837-841. [PMID: 30397276 DOI: 10.1038/s41390-018-0206-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 09/19/2018] [Accepted: 09/25/2018] [Indexed: 11/09/2022]
Abstract
BACKGROUND Congenital Disorders of Glycosylation (CDG) are genetic diseases caused by hypoglycosylation of glycoproteins and glycolipids. Most CDG are multisystem disorders with mild to severe involvement. METHODS We studied 554 patients (2007-2017) with a clinical phenotype compatible with a CDG. Screening was performed by serum transferrin isoelectric focusing. The diagnosis was confirmed by genetic testing (Sanger or exome sequencing). RESULTS A confirmed abnormal pattern was found in nine patients. Seven patients showed a type 1 pattern: four with PMM2-CDG, two with ALG2-CDG, and one with classical galactosemia. A type 2 pattern was found in two patients: one with a CDG-IIx and one with a transferrin protein variant. Abnormal transferrin pattern were observed in a patient with a myopathy due to a COL6A2 gene variant. CONCLUSIONS CDG screening in Argentina from 2007 to 2017 revealed 4 PMM2-CDG patients, 2 ALG2-CDG patients with a novel homozygous gene variant and 1 CDG-IIx.
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Affiliation(s)
- Carla Gabriela Asteggiano
- CONICET - UCC - Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Sma. Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, Córdoba, Argentina.
| | - Magali Papazoglu
- CONICET - UCC - Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Sma. Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, Córdoba, Argentina
| | - María Beatriz Bistué Millón
- CONICET - UCC - Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Sma. Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, Córdoba, Argentina
| | - María Fernanda Peralta
- CONICET - UCC - Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Sma. Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, Córdoba, Argentina
| | - Nydia Beatriz Azar
- CONICET - UCC - Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Sma. Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, Córdoba, Argentina
| | | | - Norberto Guelbert
- Servicio de Enfermedades Metabólicas, Hospital de Niños de la Sma. Trinidad, Ferroviarios 1250, Córdoba, Argentina
| | | | - Marcela Pereyra
- Servicio de Crecimiento y Desarrollo, Hospital Pediátrico Humberto Notti, Mendoza, Argentina
| | - Raquel Dodelson de Kremer
- CONICET - UCC - Centro de Estudio de las Metabolopatías Congénitas (CEMECO), Hospital de Niños de la Sma. Trinidad, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Ferroviarios 1250, Córdoba, Argentina
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Kao JC, Milone M, Selcen D, Shen XM, Engel AG, Liewluck T. Congenital myasthenic syndromes in adult neurology clinic: A long road to diagnosis and therapy. Neurology 2018; 91:e1770-e1777. [PMID: 30291185 PMCID: PMC6251603 DOI: 10.1212/wnl.0000000000006478] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 07/27/2018] [Indexed: 01/05/2023] Open
Abstract
OBJECTIVE To investigate the diagnostic challenges of congenital myasthenic syndromes (CMS) in adult neuromuscular practice. METHODS We searched the Mayo Clinic database for patients with CMS diagnosed in adulthood in the neuromuscular clinic between 2000 and 2016. Clinical, laboratory, and electrodiagnostic data were reviewed. RESULTS We identified 34 patients with CMS, 30 of whom had a molecular diagnosis (14 DOK7, 6 RAPSN, 2 LRP4, 2 COLQ, 2 slow-channel syndrome, 1 primary acetylcholine receptor deficiency, 1 AGRN, 1 GFPT1, and 1 SCN4A). Ophthalmoparesis was often mild and present in 13 patients. Predominant limb-girdle weakness occurred in 19 patients. Two patients had only ptosis. Age at onset ranged from birth to 39 years (median 5 years). The median time from onset to diagnosis was 26 years (range 4-56 years). Thirteen patients had affected family members. Fatigable weakness was present when examined. Creatine kinase was elevated in 4 of 23 patients (range 1.2-4.2 times the upper limit of normal). Repetitive nerve stimulation revealed a decrement in 30 patients. Thirty-two patients were previously misdiagnosed with seronegative myasthenia gravis (n = 16), muscle diseases (n = 15), weakness of undetermined cause (n = 8), and others (n = 4). Fifteen patients received immunotherapy or thymectomy without benefits. Fourteen of the 25 patients receiving pyridostigmine did not improve or worsen. CONCLUSION Misdiagnosis occurred in 94% of the adult patients with CMS and causes a median diagnostic delay of nearly 3 decades from symptom onset. Seronegative myasthenia gravis and muscle diseases were the 2 most common misdiagnoses, which led to treatment delay and unnecessary exposure to immunotherapy, thymectomy, or muscle biopsy.
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Affiliation(s)
- Justin C Kao
- From the Department of Neurology (J.C.K., M.M., D.S., X.-M.S., A.G.E., T.L.), Mayo Clinic, Rochester, MN; and Department of Neurology (J.C.K.), Auckland City Hospital, New Zealand
| | - Margherita Milone
- From the Department of Neurology (J.C.K., M.M., D.S., X.-M.S., A.G.E., T.L.), Mayo Clinic, Rochester, MN; and Department of Neurology (J.C.K.), Auckland City Hospital, New Zealand
| | - Duygu Selcen
- From the Department of Neurology (J.C.K., M.M., D.S., X.-M.S., A.G.E., T.L.), Mayo Clinic, Rochester, MN; and Department of Neurology (J.C.K.), Auckland City Hospital, New Zealand
| | - Xin-Ming Shen
- From the Department of Neurology (J.C.K., M.M., D.S., X.-M.S., A.G.E., T.L.), Mayo Clinic, Rochester, MN; and Department of Neurology (J.C.K.), Auckland City Hospital, New Zealand
| | - Andrew G Engel
- From the Department of Neurology (J.C.K., M.M., D.S., X.-M.S., A.G.E., T.L.), Mayo Clinic, Rochester, MN; and Department of Neurology (J.C.K.), Auckland City Hospital, New Zealand
| | - Teerin Liewluck
- From the Department of Neurology (J.C.K., M.M., D.S., X.-M.S., A.G.E., T.L.), Mayo Clinic, Rochester, MN; and Department of Neurology (J.C.K.), Auckland City Hospital, New Zealand.
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Kvarnung M, Taylan F, Nilsson D, Anderlid BM, Malmgren H, Lagerstedt-Robinson K, Holmberg E, Burstedt M, Nordenskjöld M, Nordgren A, Lundberg ES. Genomic screening in rare disorders: New mutations and phenotypes, highlighting ALG14 as a novel cause of severe intellectual disability. Clin Genet 2018; 94:528-537. [PMID: 30221345 DOI: 10.1111/cge.13448] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 09/04/2018] [Accepted: 09/11/2018] [Indexed: 01/20/2023]
Abstract
We have investigated 20 consanguineous families with multiple children affected by rare disorders. Detailed clinical examinations, exome sequencing of affected as well as unaffected family members and further validation of likely pathogenic variants were performed. In 16/20 families, we identified pathogenic variants in autosomal recessive disease genes (ALMS1, PIGT, FLVCR2, TFG, CYP7B1, ALG14, EXOSC3, MEGF10, ASAH1, WDR62, ASPM, PNPO, ERCC5, KIAA1109, RIPK4, MAN1B1). A number of these genes have only rarely been reported previously and our findings thus confirm them as disease genes, further delineate the associated phenotypes and expand the mutation spectrum with reports of novel variants. We highlight the findings in two affected siblings with splice altering variants in ALG14 and propose a new clinical entity, which includes severe intellectual disability, epilepsy, behavioral problems and mild dysmorphic features, caused by biallelic variants in ALG14.
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Affiliation(s)
- Malin Kvarnung
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Fulya Taylan
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
| | - Daniel Nilsson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden.,Science for Life Laboratory, Karolinska Institutet Science Park, Stockholm, Sweden
| | - Britt-Marie Anderlid
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Helena Malmgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Kristina Lagerstedt-Robinson
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Eva Holmberg
- Department of Medical Bioscience, Medical and Clinical Genetics, Umeå University, Umeå, Sweden
| | - Magnus Burstedt
- Department of Medical Bioscience, Medical and Clinical Genetics, Umeå University, Umeå, Sweden
| | - Magnus Nordenskjöld
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Ann Nordgren
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Elisabeth S Lundberg
- Department of Molecular Medicine and Surgery, Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden.,Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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Farmakidis C, Pasnoor M, Barohn RJ, Dimachkie MM. Congenital Myasthenic Syndromes: a Clinical and Treatment Approach. Curr Treat Options Neurol 2018; 20:36. [DOI: 10.1007/s11940-018-0520-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Abstract
PURPOSE OF REVIEW Summarize features of the currently recognized congenital myasthenic syndromes (CMS) with emphasis on novel findings identified in the past 6 years. RECENT FINDINGS Since the last review of the CMS in this journal in 2012, several novel CMS were identified. The identified disease proteins are SNAP25B, synaptotagmin 2, Munc13-1, synaptobrevin-1, GFPT1, DPAGT1, ALG2, ALG14, Agrin, GMPPB, LRP4, myosin 9A, collagen 13A1, the mitochondrial citrate carrier, PREPL, LAMA5, the vesicular ACh transporter, and the high-affinity presynaptic choline transporter. Exome sequencing has provided a powerful tool for identifying novel CMS. Identifying the disease genes is essential for determining optimal therapy. The landscape of the CMS is still unfolding.
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Affiliation(s)
- Andrew G Engel
- Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN, 55905, USA.
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Rodríguez Cruz PM, Palace J, Beeson D. The Neuromuscular Junction and Wide Heterogeneity of Congenital Myasthenic Syndromes. Int J Mol Sci 2018; 19:ijms19061677. [PMID: 29874875 PMCID: PMC6032286 DOI: 10.3390/ijms19061677] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 05/17/2018] [Accepted: 05/21/2018] [Indexed: 01/16/2023] Open
Abstract
Congenital myasthenic syndromes (CMS) are genetic disorders characterised by impaired neuromuscular transmission. This review provides an overview on CMS and highlights recent advances in the field, including novel CMS causative genes and improved therapeutic strategies. CMS due to mutations in SLC5A7 and SLC18A3, impairing the synthesis and recycling of acetylcholine, have recently been described. In addition, a novel group of CMS due to mutations in SNAP25B, SYT2, VAMP1, and UNC13A1 encoding molecules implicated in synaptic vesicles exocytosis has been characterised. The increasing number of presynaptic CMS exhibiting CNS manifestations along with neuromuscular weakness demonstrate that the myasthenia can be only a small part of a much more extensive disease phenotype. Moreover, the spectrum of glycosylation abnormalities has been increased with the report that GMPPB mutations can cause CMS, thus bridging myasthenic disorders with dystroglycanopathies. Finally, the discovery of COL13A1 mutations and laminin α5 deficiency has helped to draw attention to the role of extracellular matrix proteins for the formation and maintenance of muscle endplates. The benefit of β2-adrenergic agonists alone or combined with pyridostigmine or 3,4-Dyaminopiridine is increasingly being reported for different subtypes of CMS including AChR-deficiency and glycosylation abnormalities, thus expanding the therapeutic repertoire available.
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Affiliation(s)
- Pedro M Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford OX3 9DS, UK.
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK.
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford OX3 9DS, UK.
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43
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Maselli RA, Vázquez J, Schrumpf L, Arredondo J, Lara M, Strober JB, Pytel P, Wollmann RL, Ferns M. Presynaptic congenital myasthenic syndrome with altered synaptic vesicle homeostasis linked to compound heterozygous sequence variants in RPH3A. Mol Genet Genomic Med 2018; 6:434-440. [PMID: 29441694 PMCID: PMC6014458 DOI: 10.1002/mgg3.370] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Revised: 01/06/2018] [Accepted: 11/20/2017] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Monogenic defects of synaptic vesicle (SV) homeostasis have been implicated in many neurologic diseases, including autism, epilepsy, and movement disorders. In addition, abnormal vesicle exocytosis has been associated with several endocrine dysfunctions. METHODS We report an 11 year old girl with learning disabilities, tremors, ataxia, transient hyperglycemia, and muscle fatigability responsive to albuterol sulfate. Failure of neuromuscular transmission was confirmed by single fiber electromyography. Electron microscopy of motor nerve terminals revealed marked reduction in SV density, double-membrane-bound sacs containing SVs, abundant endosomes, and degenerative lamellar bodies. The patient underwent whole exome sequencing (WES) and relevant sequence variants were expressed and studied in a mammalian cell line. RESULTS Chromosomal microarray studies and next generation sequencing (NGS) of mitochondrial DNA were unrevealing; however, NGS of genomic DNA showed two rare sequence variants in the gene encoding rabphilin 3a (RPH3A). The paternally inherited variant c.806 G>A (p.Arg269Gln) involves a substitution of a conserved residue in the linker region, while the maternally inherited variant c.1390 G>T (p.Val464Leu) involves a conserved amino acid substitution in the highly conserved C2A region. Expression studies revealed that p.Arg269Gln strongly impairs the binding of rabphilin 3a to 14-3-3, which is a proposed regulator of synaptic transmission and plasticity. In contrast, the binding of rabphilin 3a to 14-3-3 is only marginally impaired by p.Val464Leu; thus, the pathogenic role of p.Val464Leu remains unclear. CONCLUSION In summary, we report a patient with a multisystem neurologic disorder and altered SV regulation attributed to defects in RPH3A, which grants further studies of this gene in human disorders of synaptic transmission.
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Affiliation(s)
| | - Jessica Vázquez
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Leah Schrumpf
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Juan Arredondo
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Marian Lara
- Department of NeurologyUniversity of California DavisSacramentoCAUSA
| | - Jonathan B. Strober
- Department of NeurologyUniversity of California San FranciscoSan FranciscoCAUSA
| | - Peter Pytel
- Department of PathologyUniversity of ChicagoChicagoILUSA
| | | | - Michael Ferns
- Department of Anesthesiology and Pain MedicineUniversity of California DavisSacramentoCAUSA
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Ferreira CR, Altassan R, Marques-Da-Silva D, Francisco R, Jaeken J, Morava E. Recognizable phenotypes in CDG. J Inherit Metab Dis 2018; 41:541-553. [PMID: 29654385 PMCID: PMC5960425 DOI: 10.1007/s10545-018-0156-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2017] [Revised: 12/23/2017] [Accepted: 02/06/2018] [Indexed: 01/06/2023]
Abstract
Pattern recognition, using a group of characteristic, or discriminating features, is a powerful tool in metabolic diagnostic. A classic example of this approach is used in biochemical analysis of urine organic acid analysis, where the reporting depends more on the correlation of pertinent positive and negative findings, rather than on the absolute values of specific markers. Similar uses of pattern recognition in the field of biochemical genetics include the interpretation of data obtained by metabolomics, like glycomics, where a recognizable pattern or the presence of a specific glycan sub-fraction can lead to the direct diagnosis of certain types of congenital disorders of glycosylation. Another indispensable tool is the use of clinical pattern recognition-or syndromology-relying on careful phenotyping. While genomics might uncover variants not essential in the final clinical expression of disease, and metabolomics could point to a mixture of primary but also secondary changes in biochemical pathways, phenomics describes the clinically relevant manifestations and the full expression of the disease. In the current review we apply phenomics to the field of congenital disorders of glycosylation, focusing on recognizable differentiating findings in glycosylation disorders, characteristic dysmorphic features and malformations in PMM2-CDG, and overlapping patterns among the currently known glycosylation disorders based on their pathophysiological basis.
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Affiliation(s)
- Carlos R Ferreira
- Medical Genetics Branch National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Division of Genetics and Metabolism, Children's National Medical Center, Washington, DC, USA
| | - Ruqaia Altassan
- Metabolic Center, Department of Pediatrics, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium
- Department of Development and Regeneration, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Dorinda Marques-Da-Silva
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Lisboa, Portugal
- Portuguese Association for CDG, Lisboa, Portugal
| | - Rita Francisco
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Lisboa, Portugal
- Portuguese Association for CDG, Lisboa, Portugal
| | - Jaak Jaeken
- Metabolic Center, Department of Pediatrics, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium
- Department of Development and Regeneration, Faculty of Medicine, KU Leuven, Leuven, Belgium
| | - Eva Morava
- Metabolic Center, Department of Pediatrics, University Hospitals Leuven, Herestraat 49, B-3000, Leuven, Belgium.
- Department of Development and Regeneration, Faculty of Medicine, KU Leuven, Leuven, Belgium.
- Department of Clinical Genomics, Center for Individualized Medicine, Mayo Clinic, Rochester, MN, USA.
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Ng BG, Freeze HH. Perspectives on Glycosylation and Its Congenital Disorders. Trends Genet 2018; 34:466-476. [PMID: 29606283 DOI: 10.1016/j.tig.2018.03.002] [Citation(s) in RCA: 159] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/04/2018] [Accepted: 03/05/2018] [Indexed: 12/12/2022]
Abstract
Congenital disorders of glycosylation (CDG) are a rapidly expanding group of metabolic disorders that result from abnormal protein or lipid glycosylation. They are often difficult to clinically diagnose because they broadly affect many organs and functions and lack clinical uniformity. However, recent technological advances in next-generation sequencing have revealed a treasure trove of new genetic disorders, expanded the knowledge of known disorders, and showed a critical role in infectious diseases. More comprehensive genetic tools specifically tailored for mammalian cell-based models have revealed a critical role for glycosylation in pathogen-host interactions, while also identifying new CDG susceptibility genes. We highlight recent advancements that have resulted in a better understanding of human glycosylation disorders, perspectives for potential future therapies, and mysteries for which we continue to seek new insights and solutions.
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Affiliation(s)
- Bobby G Ng
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Hudson H Freeze
- Human Genetics Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA.
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46
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Lee M, Beeson D, Palace J. Therapeutic strategies for congenital myasthenic syndromes. Ann N Y Acad Sci 2018; 1412:129-136. [DOI: 10.1111/nyas.13538] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Revised: 09/28/2017] [Accepted: 10/02/2017] [Indexed: 12/20/2022]
Affiliation(s)
- Manon Lee
- Nuffield Department of Clinical Neurosciences; John Radcliffe Hospital; Oxford United Kingdom
| | - David Beeson
- The Weatherall Institute of Molecular Medicine, John Radcliffe Hospital; University of Oxford; Oxford United Kingdom
| | - Jacqueline Palace
- Nuffield Department of Clinical Neurosciences; John Radcliffe Hospital; Oxford United Kingdom
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Fernández-Marmiesse A, Gouveia S, Couce ML. NGS Technologies as a Turning Point in Rare Disease Research , Diagnosis and Treatment. Curr Med Chem 2018; 25:404-432. [PMID: 28721829 PMCID: PMC5815091 DOI: 10.2174/0929867324666170718101946] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2017] [Revised: 06/19/2017] [Accepted: 07/14/2017] [Indexed: 01/17/2023]
Abstract
Approximately 25-50 million Americans, 30 million Europeans, and 8% of the Australian population have a rare disease. Rare diseases are thus a common problem for clinicians and account for enormous healthcare costs worldwide due to the difficulty of establishing a specific diagnosis. In this article, we review the milestones achieved in our understanding of rare diseases since the emergence of next-generation sequencing (NGS) technologies and analyze how these advances have influenced research and diagnosis. The first half of this review describes how NGS has changed diagnostic workflows and provided an unprecedented, simple way of discovering novel disease-associated genes. We focus particularly on metabolic and neurodevelopmental disorders. NGS has enabled cheap and rapid genetic diagnosis, highlighted the relevance of mosaic and de novo mutations, brought to light the wide phenotypic spectrum of most genes, detected digenic inheritance or the presence of more than one rare disease in the same patient, and paved the way for promising new therapies. In the second part of the review, we look at the limitations and challenges of NGS, including determination of variant causality, the loss of variants in coding and non-coding regions, and the detection of somatic mosaicism variants and epigenetic mutations, and discuss how these can be overcome in the near future.
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Affiliation(s)
- Ana Fernández-Marmiesse
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, Spain
| | - Sofía Gouveia
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, Spain
| | - María L. Couce
- Unit of Diagnosis and Treatment of Congenital Metabolic Diseases, Department of Pediatrics, Hospital Clínico Universitario de Santiago de Compostela, Santiago de Compostela, Spain
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48
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Beeson D, Cossins J, Rodriguez-Cruz P, Maxwell S, Liu WW, Palace J. Myasthenic syndromes due to defects in COL13A1 and in the N-linked glycosylation pathway. Ann N Y Acad Sci 2018; 1413:163-169. [DOI: 10.1111/nyas.13576] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 11/09/2017] [Accepted: 11/14/2017] [Indexed: 12/11/2022]
Affiliation(s)
- David Beeson
- Neurosciences Group, Nuffield Department of Clinical Neuroscience; Weatherall Institute of Molecular Medicine; The John Radcliffe Oxford UK
| | - Judith Cossins
- Neurosciences Group, Nuffield Department of Clinical Neuroscience; Weatherall Institute of Molecular Medicine; The John Radcliffe Oxford UK
| | - Pedro Rodriguez-Cruz
- Neurosciences Group, Nuffield Department of Clinical Neuroscience; Weatherall Institute of Molecular Medicine; The John Radcliffe Oxford UK
| | - Susan Maxwell
- Neurosciences Group, Nuffield Department of Clinical Neuroscience; Weatherall Institute of Molecular Medicine; The John Radcliffe Oxford UK
| | - Wei-Wei Liu
- Neurosciences Group, Nuffield Department of Clinical Neuroscience; Weatherall Institute of Molecular Medicine; The John Radcliffe Oxford UK
| | - Jacqueline Palace
- Nuffield Department of Clinical Neuroscience; Level 3 The West Wing; The John Radcliffe Oxford UK
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Abstract
PURPOSE OF REVIEW Congenital myasthenic syndromes (CMS) are a group of heterogeneous inherited disorders caused by mutations in genes encoding proteins essential for the integrity of neuromuscular transmission. This review updates the reader on recent findings that have expanded the phenotypic spectrum and suggested improved treatment strategies. RECENT FINDINGS The use of next-generation sequencing is continuing to unearth new genes in which mutations can give rise to defective neuromuscular transmission. The defective transmission may be part of an overall more complex phenotype in which there may be muscle, central nervous system or other involvement. Notably, mutations in series of genes encoding presynaptic proteins are being identified. Further work on mutations found in the AGRN-MUSK acetylcholine receptor clustering pathway has helped characterize the role of LRP4 and broadened the phenotypic spectrum for AGRN mutations. Mutations in another extracellular matrix protein, collagen 13A1 and in GMPPB have also been found to cause a CMS. Finally, there are an increasing number of reports for the beneficial effects of treatment with β2-adrenergic receptor agonists. SUMMARY Recent studies of the CMS illustrate the increasing complexity of the genetics, pathophysiological mechanisms and the need to tailor therapy for the genetic disorders of the neuromuscular junction.
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50
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Li ST, Wang N, Xu XX, Fujita M, Nakanishi H, Kitajima T, Dean N, Gao XD. Alternative routes for synthesis of N-linked glycans by Alg2 mannosyltransferase. FASEB J 2018; 32:2492-2506. [PMID: 29273674 DOI: 10.1096/fj.201701267r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Asparagine ( N)-linked glycosylation requires the ordered, stepwise synthesis of lipid-linked oligosaccharide (LLO) precursor Glc3Man9GlcNAc2-pyrophosphate-dolichol (Glc3Man9Gn2-PDol) on the endoplasmic reticulum. The fourth and fifth steps of LLO synthesis are catalyzed by Alg2, an unusual mannosyltransferase (MTase) with two different MTase activities; Alg2 adds both an α1,3- and α1,6-mannose onto ManGlcNAc2-PDol to form the trimannosyl core Man3GlcNAc2-PDol. The biochemical properties of Alg2 are controversial and remain undefined. In this study, a liquid chromatography/mass spectrometry-based quantitative assay was established and used to analyze the MTase activities of purified yeast Alg2. Alg2-dependent Man3GlcNAc2-PDol production relied on net-neutral lipids with a propensity to form bilayers. We further showed addition of the α1,3- and α1,6-mannose can occur independently in either order but at differing rates. The conserved C-terminal EX7E motif, N-terminal cytosolic tail, and 3 G-rich loop motifs in Alg2 play crucial roles for these activities, both in vitro and in vivo. These findings provide insight into the unique bifunctionality of Alg2 during LLO synthesis and lead to a new model in which alternative, independent routes exist for Alg2 catalysis of the trimannosyl core oligosaccharide.-Li, S.-T., Wang, N., Xu, X.-X., Fujita, M., Nakanishi, H., Kitajima, T., Dean, N., Gao, X.-D. Alternative routes for synthesis of N-linked glycans by Alg2 mannosyltransferase.
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Affiliation(s)
- Sheng-Tao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Toshihiko Kitajima
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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