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Feng H, Clatot J, Kaneko K, Flores-Mendez M, Wengert ER, Koutcher C, Hoddeson E, Lopez E, Lee D, Arias L, Liang Q, Zhang X, Somarowthu A, Covarrubias M, Gunthorpe MJ, Large CH, Akizu N, Goldberg EM. Targeted therapy improves cellular dysfunction, ataxia, and seizure susceptibility in a model of a progressive myoclonus epilepsy. Cell Rep Med 2024; 5:101389. [PMID: 38266642 PMCID: PMC10897515 DOI: 10.1016/j.xcrm.2023.101389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 11/09/2023] [Accepted: 12/20/2023] [Indexed: 01/26/2024]
Abstract
The recurrent variant KCNC1-p.Arg320His causes progressive myoclonus epilepsy (EPM) type 7, defined by progressive myoclonus, epilepsy, and ataxia, and is without effective treatment. KCNC1 encodes the voltage-gated potassium channel subunit Kv3.1, specifically expressed in high-frequency-firing neurons. Variant subunits act via loss of function; hence, EPM7 pathogenesis may involve impaired excitability of Kv3.1-expressing neurons, while enhancing Kv3 activity could represent a viable therapeutic strategy. We generate a mouse model, Kcnc1-p.Arg320His/+, which recapitulates the core features of EPM7, including progressive ataxia and seizure susceptibility. Kv3.1-expressing cerebellar granule cells and neocortical parvalbumin-positive GABAergic interneurons exhibit abnormalities consistent with Kv3 channel dysfunction. A Kv3-specific positive modulator (AUT00206) selectively enhances the firing frequency of Kv3.1-expressing neurons and improves motor function and seizure susceptibility in Kcnc1-Arg320His/+ mice. This work identifies a cellular and circuit basis of dysfunction in EPM7 and demonstrates that Kv3 positive modulators such as AUT00206 have therapeutic potential for the treatment of EPM7.
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Affiliation(s)
- Huijie Feng
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Jerome Clatot
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Keisuke Kaneko
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Anesthesiology, Nihon University, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Marco Flores-Mendez
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Eric R Wengert
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Carly Koutcher
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emily Hoddeson
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Emily Lopez
- The University of Pennsylvania School of Arts and Sciences, Philadelphia, PA, USA
| | - Demetrius Lee
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Leroy Arias
- The University of Pennsylvania School of Arts and Sciences, Philadelphia, PA, USA
| | - Qiansheng Liang
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Xiaohong Zhang
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ala Somarowthu
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Manuel Covarrubias
- Department of Neuroscience and Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Martin J Gunthorpe
- Autifony Therapeutics, Ltd., Stevenage Bioscience Catalyst, Stevenage SG1 2FX, UK
| | - Charles H Large
- Autifony Therapeutics, Ltd., Stevenage Bioscience Catalyst, Stevenage SG1 2FX, UK
| | - Naiara Akizu
- The Raymond G. Perelman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Departments of Pathology & Laboratory Medicine, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; The Epilepsy Neurogenetics Initiative, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Neurology, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA; Department of Neuroscience, The University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA.
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2
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Gardella E, Michelucci R, Christensen HM, Fenger CD, Reale C, Riguzzi P, Pasini E, Albini-Riccioli L, Papa V, Foschini MP, Cenacchi G, Furia F, Marjanovic D, Hammer TB, Møller RS, Rubboli G. IRF2BPL as a novel causative gene for progressive myoclonus epilepsy. Epilepsia 2023; 64:e170-e176. [PMID: 37114479 DOI: 10.1111/epi.17634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 04/25/2023] [Accepted: 04/26/2023] [Indexed: 04/29/2023]
Abstract
IRF2BPL has recently been described as a novel cause of neurodevelopmental disorders with multisystemic regression, epilepsy, cerebellar symptoms, dysphagia, dystonia, and pyramidal signs. We describe a novel IRF2BPL phenotype consistent with progressive myoclonus epilepsy (PME) in three novel subjects and review the features of the 31 subjects with IRF2BPL-related disorders previously reported. Our three probands, aged 28-40 years, harbored de novo nonsense variants in IRF2BPL (c.370C > T, p.[Gln124*] and c.364C > T; p.[Gln122*], respectively). From late childhood/adolescence, they presented with severe myoclonus epilepsy, stimulus-sensitive myoclonus, and progressive cognitive, speech, and cerebellar impairment, consistent with a typical PME syndrome. The skin biopsy revealed massive intracellular glycogen inclusions in one proband, suggesting a similar pathogenic pathway to other storage disorders. Whereas the two older probands were severely affected, the younger proband had a milder PME phenotype, partially overlapping with some of the previously reported IRF2BPL cases, suggesting that some of them might be unrecognized PME. Interestingly, all three patients harbored protein-truncating variants clustered in a proximal, highly conserved gene region around the "coiled-coil" domain. Our data show that PME can be an additional phenotype within the spectrum of IRF2BPL-related disorders and suggest IRF2BPL as a novel causative gene for PME.
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Affiliation(s)
- Elena Gardella
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Department of Clinical Neurophysiology, Danish Epilepsy Center, Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
- European Reference Network for Rare and Complex epilepsies (ERN) EpiCARE, University Hospitals of Lyon, Lyon, France
| | - Roberto Michelucci
- IRCCS-Istituto delle Scienze Neurologiche di Bologna, Unit of Neurology, Bellaria Hospital, Bologna, Italy
| | | | - Christina D Fenger
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
| | - Chiara Reale
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Child Neuropsychiatry Unit, Department of Surgical Sciences, Dentistry, Gynecology, and Pediatrics, University of Verona, Verona, Italy
| | - Patrizia Riguzzi
- IRCCS-Istituto delle Scienze Neurologiche di Bologna, Unit of Neurology, Bellaria Hospital, Bologna, Italy
| | - Elena Pasini
- IRCCS-Istituto delle Scienze Neurologiche di Bologna, Unit of Neurology, Bellaria Hospital, Bologna, Italy
| | - Luca Albini-Riccioli
- IRCCS-Istituto delle Scienze Neurologiche di Bologna, Unit of Neuroradiology, Bellaria Hospital, Bologna, Italy
| | | | - Maria Pia Foschini
- Unit of Pathological Anatomy, University of Bologna, Bellaria Hospital, Bologna, Italy
| | - Giovanna Cenacchi
- DIBINEM, University of Bologna, Bologna, Italy
- Unit of Pathological Anatomy, IRCCS Azienda Ospedaliera Universitaria S.Orsola-Malpighi, Bologna, Italy
| | - Francesca Furia
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | | | - Trine B Hammer
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Department of Genetics, Rigshospitalet, Copenhagen, Denmark
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
- European Reference Network for Rare and Complex epilepsies (ERN) EpiCARE, University Hospitals of Lyon, Lyon, France
| | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center, Dianalund, Denmark
- European Reference Network for Rare and Complex epilepsies (ERN) EpiCARE, University Hospitals of Lyon, Lyon, France
- Department of Neurology, Danish Epilepsy Center, Dianalund, Denmark
- University of Copenhagen, Copenhagen, Denmark
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3
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Indrawinata K, Argiropoulos P, Sugita S. Structural and functional understanding of disease-associated mutations in V-ATPase subunit a1 and other isoforms. Front Mol Neurosci 2023; 16:1135015. [PMID: 37465367 PMCID: PMC10352029 DOI: 10.3389/fnmol.2023.1135015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Accepted: 06/09/2023] [Indexed: 07/20/2023] Open
Abstract
The vacuolar-type ATPase (V-ATPase) is a multisubunit protein composed of the cytosolic adenosine triphosphate (ATP) hydrolysis catalyzing V1 complex, and the integral membrane complex, Vo, responsible for proton translocation. The largest subunit of the Vo complex, subunit a, enables proton translocation upon ATP hydrolysis, mediated by the cytosolic V1 complex. Four known subunit a isoforms (a1-a4) are expressed in different cellular locations. Subunit a1 (also known as Voa1), the neural isoform, is strongly expressed in neurons and is encoded by the ATP6V0A1 gene. Global knockout of this gene in mice causes embryonic lethality, whereas pyramidal neuron-specific knockout resulted in neuronal cell death with impaired spatial and learning memory. Recently reported, de novo and biallelic mutations of the human ATP6V0A1 impair autophagic and lysosomal activities, contributing to neuronal cell death in developmental and epileptic encephalopathies (DEE) and early onset progressive myoclonus epilepsy (PME). The de novo heterozygous R740Q mutation is the most recurrent variant reported in cases of DEE. Homology studies suggest R740 deprotonates protons from specific glutamic acid residues in subunit c, highlighting its importance to the overall V-ATPase function. In this paper, we discuss the structure and mechanism of the V-ATPase, emphasizing how mutations in subunit a1 can lead to lysosomal and autophagic dysfunction in neurodevelopmental disorders, and how mutations to the non-neural isoforms, a2-a4, can also lead to various genetic diseases. Given the growing discovery of disease-causing variants of V-ATPase subunit a and its function as a pump-based regulator of intracellular organelle pH, this multiprotein complex warrants further investigation.
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Affiliation(s)
- Karen Indrawinata
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Peter Argiropoulos
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Shuzo Sugita
- Division of Translational and Experimental Neuroscience, Krembil Brain Institute, University Health Network, Toronto, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
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4
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Castellotti B, Canafoglia L, Freri E, Tappatà M, Messina G, Magri S, DiFrancesco JC, Fanella M, Di Bonaventura C, Morano A, Granata T, Gellera C, Franceschetti S, Michelucci R. Progressive myoclonus epilepsies due to SEMA6B mutations. New variants and appraisal of published phenotypes. Epilepsia Open 2023; 8:645-650. [PMID: 36719163 PMCID: PMC10235579 DOI: 10.1002/epi4.12697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 01/20/2023] [Indexed: 02/01/2023] Open
Abstract
Variants of SEMA6B have been identified in an increasing number of patients, often presenting with progressive myoclonus epilepsy (PME), and to lesser extent developmental encephalopathy, with or without epilepsy. The exon 17 is mainly involved, with truncating mutations causing the production of aberrant proteins with toxic gain of function. Herein, we describe three adjunctive patients carrying de novo truncating SEMA6B variants in this exon (c.1976delC and c.2086C > T novel; c.1978delC previously reported). These subjects presented with PME preceded by developmental delay, motor and cognitive impairment, worsening myoclonus, and epilepsy with polymorphic features, including focal to bilateral seizures in two, and non-convulsive status epilepticus in one. The evidence of developmental delay in these cases suggests their inclusion in the "PME plus developmental delay" nosological group. This work further expands our knowledge of SEMA6B variants causing PMEs. However, the data to date available confirms that phenotypic features do not correlate with the type or location of variants, aspects that need to be further clarified by future studies.
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Affiliation(s)
- Barbara Castellotti
- Department of Diagnostic and Technology, Unit of Medical Genetics and NeurogeneticsFondazione IRCCS Istituto Neurologico Carlo BestaMilanoItaly
| | - Laura Canafoglia
- Integrated Diagnostics for Epilepsy, Department of Diagnostic and TechnologyFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | - Elena Freri
- Department of Pediatric NeuroscienceFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | - Maria Tappatà
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Epilepsy Center, Unit of NeurologyBellaria HospitalBolognaItaly
| | - Giuliana Messina
- Department of Diagnostic and Technology, Unit of Medical Genetics and NeurogeneticsFondazione IRCCS Istituto Neurologico Carlo BestaMilanoItaly
| | - Stefania Magri
- Department of Diagnostic and Technology, Unit of Medical Genetics and NeurogeneticsFondazione IRCCS Istituto Neurologico Carlo BestaMilanoItaly
| | - Jacopo C. DiFrancesco
- Department of Pediatric NeuroscienceFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
- Department of Neurology, Fondazione IRCCS San Gerardo dei TintoriUniversity of Milano‐BicoccaMonzaItaly
| | - Martina Fanella
- Department of NeurologyFabrizio Spaziani HospitalFrosinoneItaly
| | - Carlo Di Bonaventura
- Department of Human NeurosciencesPoliclinico Umberto I, Sapienza University of RomeRomeItaly
| | - Alessandra Morano
- Department of Human NeurosciencesPoliclinico Umberto I, Sapienza University of RomeRomeItaly
| | - Tiziana Granata
- Department of Pediatric NeuroscienceFondazione IRCCS Istituto Neurologico Carlo BestaMilanItaly
| | - Cinzia Gellera
- Department of Diagnostic and Technology, Unit of Medical Genetics and NeurogeneticsFondazione IRCCS Istituto Neurologico Carlo BestaMilanoItaly
| | | | - Roberto Michelucci
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Epilepsy Center, Unit of NeurologyBellaria HospitalBolognaItaly
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5
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Courage C, Oliver KL, Park EJ, Cameron JM, Grabińska KA, Muona M, Canafoglia L, Gambardella A, Said E, Afawi Z, Baykan B, Brandt C, di Bonaventura C, Chew HB, Criscuolo C, Dibbens LM, Castellotti B, Riguzzi P, Labate A, Filla A, Giallonardo AT, Berecki G, Jackson CB, Joensuu T, Damiano JA, Kivity S, Korczyn A, Palotie A, Striano P, Uccellini D, Giuliano L, Andermann E, Scheffer IE, Michelucci R, Bahlo M, Franceschetti S, Sessa WC, Berkovic SF, Lehesjoki AE. Progressive myoclonus epilepsies-Residual unsolved cases have marked genetic heterogeneity including dolichol-dependent protein glycosylation pathway genes. Am J Hum Genet 2021; 108:722-738. [PMID: 33798445 DOI: 10.1016/j.ajhg.2021.03.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 03/05/2021] [Indexed: 02/04/2023] Open
Abstract
Progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous rare diseases. Over 70% of PME cases can now be molecularly solved. Known PME genes encode a variety of proteins, many involved in lysosomal and endosomal function. We performed whole-exome sequencing (WES) in 84 (78 unrelated) unsolved PME-affected individuals, with or without additional family members, to discover novel causes. We identified likely disease-causing variants in 24 out of 78 (31%) unrelated individuals, despite previous genetic analyses. The diagnostic yield was significantly higher for individuals studied as trios or families (14/28) versus singletons (10/50) (OR = 3.9, p value = 0.01, Fisher's exact test). The 24 likely solved cases of PME involved 18 genes. First, we found and functionally validated five heterozygous variants in NUS1 and DHDDS and a homozygous variant in ALG10, with no previous disease associations. All three genes are involved in dolichol-dependent protein glycosylation, a pathway not previously implicated in PME. Second, we independently validate SEMA6B as a dominant PME gene in two unrelated individuals. Third, in five families, we identified variants in established PME genes; three with intronic or copy-number changes (CLN6, GBA, NEU1) and two very rare causes (ASAH1, CERS1). Fourth, we found a group of genes usually associated with developmental and epileptic encephalopathies, but here, remarkably, presenting as PME, with or without prior developmental delay. Our systematic analysis of these cases suggests that the small residuum of unsolved cases will most likely be a collection of very rare, genetically heterogeneous etiologies.
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Affiliation(s)
- Carolina Courage
- Folkhälsan Research Center, Helsinki 00290, Finland; Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki 00290, Finland
| | - Karen L Oliver
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia; Population Health and Immunity Division, the Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, the University of Melbourne, Melbourne, VIC 3010, Australia
| | - Eon Joo Park
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Jillian M Cameron
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia
| | - Kariona A Grabińska
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Mikko Muona
- Folkhälsan Research Center, Helsinki 00290, Finland; Blueprint Genetics, Espoo 02150, Finland
| | - Laura Canafoglia
- Neurophysiopathology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20133, Italy
| | | | - Edith Said
- Section of Medical Genetics, Mater dei Hospital, Msida MSD2090, Malta; Department of Anatomy and Cell Biology, University of Malta, Msida MSD2090, Malta
| | - Zaid Afawi
- Center for Neuroscience, Ben-Gurion University of the Negev, Be'er Sheva 8410402, Israel
| | - Betul Baykan
- Departments of Neurology and Clinical Neurophysiology, Istanbul Faculty of Medicine, Istanbul University, Istanbul 34452, Turkey
| | | | - Carlo di Bonaventura
- Department of Human Neurosciences, Sapienza University of Rome, Viale dell'Università, 30, 00185 Rome, Italy
| | - Hui Bein Chew
- Genetics Department, Kuala Lumpur Hospital, Ministry of Health Malaysia, Jalan Pahang, 50586 Kuala Lumpur, Malaysia
| | - Chiara Criscuolo
- Department of Neuroscience, Reproductive, and Odontostomatological Sciences, University of Naples Federico II, Naples 80138, Italy
| | - Leanne M Dibbens
- Epilepsy Research Group, Australian Centre for Precision Health, UniSA Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Barbara Castellotti
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, IRCCS Istituto Neurologico Carlo Besta Milan 20133, Italy
| | - Patrizia Riguzzi
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Unit of Neurology, Bellaria Hospital, Bologna 40139, Italy
| | - Angelo Labate
- Institute of Neurology, University Magna Græcia, Catanzaro 88100, Italy
| | - Alessandro Filla
- Department of Neuroscience, Reproductive, and Odontostomatological Sciences, University of Naples Federico II, Naples 80138, Italy
| | - Anna T Giallonardo
- Neurology Unit, Human Neurosciences Department, Sapienza University, Rome 00185, Italy
| | - Geza Berecki
- Ion Channels and Disease Group, Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Christopher B Jackson
- Stem Cells and Metabolism Research Program, Faculty of Medicine, University of Helsinki, 00290 Helsinki, Finland
| | | | - John A Damiano
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia
| | - Sara Kivity
- Epilepsy Unit, Schneider Children's Medical Center of Israel, Petah Tiqvah 4922297, Israel
| | - Amos Korczyn
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 60198, Israel
| | - Aarno Palotie
- Institute for Molecular Medicine Finland (FIMM), HiLIFE, University of Helsinki, Helsinki 00290, Finland; Analytic and Translational Genetics Unit, Department of Medicine, Department of Neurology and Department of Psychiatry Massachusetts General Hospital, Boston, MA 02114, USA; The Stanley Center for Psychiatric Research and Program in Medical and Population Genetics, The Broad Institute of MIT and Harvard, Cambridge, Boston, MA 02142, USA
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto "G. Gaslini," Genova 16147, Italy
| | - Davide Uccellini
- Neurology - Neurophysiology Unit, ASST dei Sette Laghi, Galmarini Tradate Hospital, Tradate 21049, Italy
| | - Loretta Giuliano
- Dipartimento "G.F. Ingrassia," Università degli Studi di Catania, Catania 95131, Italy
| | - Eva Andermann
- Neurogenetics Unit and Epilepsy Research Group, Montreal Neurological Hospital and Institute, Montreal, QC H3A 2B4, Canada; Departments of Neurology & Neurosurgery and Human Genetics, McGill University, Montreal, QC H3A 0G4, Canada
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia; Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, VIC 3052, Australia; Department of Paediatrics, The University of Melbourne, Royal Children's Hospital, Parkville, VIC 3052, Australia; The Florey Institute, Parkville, VIC 3052, Australia
| | - Roberto Michelucci
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Unit of Neurology, Bellaria Hospital, Bologna 40139, Italy
| | - Melanie Bahlo
- Population Health and Immunity Division, the Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, the University of Melbourne, Melbourne, VIC 3010, Australia
| | - Silvana Franceschetti
- Neurophysiopathology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan 20133, Italy
| | - William C Sessa
- Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06520, USA
| | - Samuel F Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Heidelberg 3084, Victoria, Australia.
| | - Anna-Elina Lehesjoki
- Folkhälsan Research Center, Helsinki 00290, Finland; Department of Medical and Clinical Genetics, Medicum, University of Helsinki, Helsinki 00290, Finland.
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Abstract
The progressive myoclonus epilepsy (PME) is a rare group of clinically and genetically heterogeneous disorders characterized by myoclonus, drug refractory epilepsy, and neurological deterioration. Here, we report a three-year-old female patient with neuroregression after a period of normal development and uncontrollable myoclonic seizures, which fulfill the criteria of PME. Next-generation sequencing revealed a novel homozygous mutation of variant c.173G>C in exon 2 of the KCDT7 (potassium channel tetramerization domain containing protein 7) gene that was compatible with the diagnosis of progressive myoclonic epilepsy 3 (PME3) with or without intracellular inclusions. This is a rare report of KCTD7 mutations causing PME in the Indian population. Our findings supported the important role of KCTD7 in PME and broadened the mutation spectrum.
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Affiliation(s)
- Sai Chandar Dudipala
- Pediatric Neurology, Star Women & Children Hospital, Karimnagar, IND.,Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
| | - Prashanthi M
- Pediatrics, Prathima Institute of Medical Sciences, Karimnagar, IND
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Hotait M, Dirani M, El Halabi T, Beydoun A. Case Report: Distinctive EEG Patterns in SCARB-2 Related Progressive Myoclonus Epilepsy. Front Genet 2020; 11:581253. [PMID: 33343627 PMCID: PMC7744754 DOI: 10.3389/fgene.2020.581253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 10/28/2020] [Indexed: 11/13/2022] Open
Abstract
Action myoclonus-renal failure syndrome (AMRF) is a rare, recessively inherited form of progressive myoclonus epilepsy (PME) caused by mutations in the SCARB2 gene and associated with end-stage renal failure. In addition to severe progressive myoclonus, the neurological manifestations of this syndrome are characterized by progressive ataxia and dysarthria with preserved intellectual capacity. Since its original description, an increasing number of "AMRF-like" cases without renal failure have been reported. We describe the case of a 29-year-old woman with progressive disabling myoclonus associated with dysarthria and ataxia who was found to have a novel homozygous frameshift mutation in the SCARB2 gene. In addition, this report emphasizes the presence of two EEG patterns, fixation-off phenomenon, and bursts of parasagittal spikes exclusively seen during REM sleep that appear to be characteristic of this condition.
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Affiliation(s)
- Mostafa Hotait
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Maya Dirani
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Tarek El Halabi
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
| | - Ahmad Beydoun
- Department of Neurology, American University of Beirut Medical Center, Beirut, Lebanon
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8
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Ragona F, Canafoglia L, Castellotti B, Solazzi R, Gabbiadini S, Freri E, Scaioli V, DiFrancesco JC, Gellera C, Granata T. Early Parkinsonism in a Senegalese girl with Lafora disease. Epileptic Disord 2020; 22:233-6. [PMID: 32301727 DOI: 10.1684/epd.2020.1150] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We report the atypical presentation of Lafora disease in a Senegalese girl carrying the homozygous variant, c.560A>C, in the NHLRC1 gene. At 13 years, the patient developed myoclonic and visual seizures, progressive psychomotor slowing, and cognitive decline. At 14 years, a neurological examination showed severe hypomimia, bradykinesia, rigidity and low-amplitude myoclonic jerks. Flash-visual and somatosensory evoked potentials showed an increased amplitude of the cortical components, while an electroretinogram showed attenuated responses. An EEG showed diffuse polyspikes associated with positive-negative jerks as well as posterior slow waves and irregular spikes. The electroclinical picture suggested the diagnosis of Lafora disease regarding the association of visual seizures, cognitive deterioration, and action myoclonus, together with the EEG and evoked potential findings. Two uncommon findings were the prominence of extrapyramidal signs in the early stage of disease (which are rarely reported) and attenuation of electroretinal responses. We consider that Lafora disease should be included in the diagnostic work-up for juvenile Parkinsonism, when associated with epilepsy.
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9
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Abstract
Progressive myoclonus epilepsies (PMEs) are a group of genetic neurological disorders characterised by the occurrence of epileptic seizures, myoclonus and progressive neurological deterioration including cerebellar involvement and dementia. The primary cause of PMEs is variable and alterations in the corresponding mutated genes determine the progression and severity of the disease. In most cases, they lead to the death of the patient after a period of prolonged disability. PMEs also share poor information on the pathophysiological bases and the lack of a specific treatment. Recent reports suggest that neuroinflammation is a common trait under all these conditions. Here, we review similarities and differences in neuroinflammatory response in several PMEs and discuss the window of opportunity of using anti-inflammatory drugs in the treatment of several of these conditions.
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10
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Martin S, Strzelczyk A, Lindlar S, Krause K, Reif PS, Menzler K, Chiocchetti AG, Rosenow F, Knake S, Klein KM. Drug-Resistant Juvenile Myoclonic Epilepsy: Misdiagnosis of Progressive Myoclonus Epilepsy. Front Neurol 2019; 10:946. [PMID: 31551911 PMCID: PMC6746890 DOI: 10.3389/fneur.2019.00946] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/15/2019] [Indexed: 12/30/2022] Open
Abstract
Juvenile myoclonic epilepsy (JME) is a common epilepsy syndrome characterized by bilateral myoclonic and tonic-clonic seizures typically starting in adolescence and responding well to medication. Misdiagnosis of a more severe progressive myoclonus epilepsy (PME) as JME has been suggested as a cause of drug-resistance. Medical records of the Epilepsy Center Hessen-Marburg between 2005 and 2014 were automatically selected using keywords and manually reviewed regarding the presence of a JME diagnosis at any timepoint. The identified patients were evaluated regarding seizure outcome and drug resistance according to ILAE criteria. 87/168 identified JME patients were seizure-free at last follow-up including 61 drug-responsive patients (group NDR). Seventy-eight patients were not seizure-free including 26 drug-resistant patients (group DR). Valproate was the most efficacious AED. The JME diagnosis was revised in 7 patients of group DR including 6 in whom the diagnosis had already been questioned or revised during clinical follow-up. One of these was finally diagnosed with PME (genetically confirmed Lafora disease) based on genetic testing. She was initially reviewed at age 29 yrs and considered to be inconsistent with PME. Intellectual disability (p = 0.025), cognitive impairment (p < 0.001), febrile seizures in first-degree relatives (p = 0.023) and prominent dialeptic seizures (p = 0.009) where significantly more frequent in group DR. Individuals with PME are rarely found among drug-resistant alleged JME patients in a tertiary epilepsy center. Even a very detailed review by experienced epileptologists may not identify the presence of PME before the typical features evolve underpinning the need for early genetic testing in drug-resistant JME patients.
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Affiliation(s)
- Sarah Martin
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Hessen, Department of Neurology, Philipps University Marburg, Marburg, Germany
| | - Adam Strzelczyk
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Hessen, Department of Neurology, Philipps University Marburg, Marburg, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University, Frankfurt am Main, Germany
| | - Silvia Lindlar
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe University, Frankfurt am Main, Germany
| | - Kristina Krause
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Hessen, Department of Neurology, Philipps University Marburg, Marburg, Germany
| | - Philipp S Reif
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University, Frankfurt am Main, Germany
| | - Katja Menzler
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Hessen, Department of Neurology, Philipps University Marburg, Marburg, Germany
| | - Andreas G Chiocchetti
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Department of Child and Adolescent Psychiatry, Psychosomatics and Psychotherapy, Goethe University, Frankfurt am Main, Germany
| | - Felix Rosenow
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Hessen, Department of Neurology, Philipps University Marburg, Marburg, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University, Frankfurt am Main, Germany
| | - Susanne Knake
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Hessen, Department of Neurology, Philipps University Marburg, Marburg, Germany
| | - Karl Martin Klein
- Center for Personalized Translational Epilepsy Research (CePTER), Frankfurt am Main, Germany.,Epilepsy Center Hessen, Department of Neurology, Philipps University Marburg, Marburg, Germany.,Epilepsy Center Frankfurt Rhine-Main, Department of Neurology, Goethe University, Frankfurt am Main, Germany.,Departments of Clinical Neurosciences, Medical Genetics and Community Health Sciences, Hotchkiss Brain Institute, Alberta Children's Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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11
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Serino D, Davico C, Specchio N, Marras CE, Fioretto F. Berardinelli-Seip syndrome and progressive myoclonus epilepsy. Epileptic Disord 2019; 21:117-21. [PMID: 30767895 DOI: 10.1684/epd.2019.1038] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Berardinelli-Seip syndrome, or congenital generalized lipodystrophy type 2 (CGL2), is characterized by a lack of subcutaneous adipose tissue and precocious metabolic syndrome with insulin resistance, resulting in diabetes, dyslipidaemia, hepatic steatosis, cardiomyopathy, and acanthosis nigricans. Most reported mutations are associated with mild, non-progressive neurological impairment. We describe the clinical and EEG data of a patient with progressive myoclonus epilepsy (PME), CGL2, and progressive neurological impairment, carrying a homozygous BSCL2 nonsense mutation. The patient had epilepsy onset at the age of two, characterized by monthly generalized tonic-clonic seizures. By the age of three, he presented with drug-resistant ongoing myoclonic absence seizures, photosensitivity, progressive neurological degeneration, and moderate cognitive delay. Molecular analysis of the BSCL2 gene yielded a homozygous c.(1076dupC) p.(Glu360*) mutation. Application of a vagus nerve stimulator led to temporary improvement in seizure frequency, general neurological condition, and EEG background activity. Specific BSCL2 mutations may lead to a peculiar CGL2 phenotype characterized by PME and progressive neurodegeneration. Application of a vagus nerve stimulator, rarely used for PMEs, may prove beneficial, if only temporarily, for both seizure frequency and general neurological condition.
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12
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Jepson JEC, Praschberger R, Krishnakumar SS. Mechanisms of Neurological Dysfunction in GOSR2 Progressive Myoclonus Epilepsy, a Golgi SNAREopathy. Neuroscience 2019; 420:41-49. [PMID: 30954670 DOI: 10.1016/j.neuroscience.2019.03.057] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 03/22/2019] [Accepted: 03/26/2019] [Indexed: 10/27/2022]
Abstract
Successive fusion events between transport vesicles and their target membranes mediate trafficking of secreted, membrane- and organelle-localised proteins. During the initial steps of this process, termed the secretory pathway, COPII vesicles bud from the endoplasmic reticulum (ER) and fuse with the cis-Golgi membrane, thus depositing their cargo. This fusion step is driven by a quartet of SNARE proteins that includes the cis-Golgi t-SNARE Membrin, encoded by the GOSR2 gene. Mis-sense mutations in GOSR2 result in Progressive Myoclonus Epilepsy (PME), a severe neurological disorder characterised by ataxia, myoclonus and seizures in the absence of significant cognitive impairment. However, given the ubiquitous and essential function of ER-to-Golgi transport, why GOSR2 mutations cause neurological dysfunction and not lethality or a broader range of developmental defects has remained an enigma. Here we highlight new work that has shed light on this issue and incorporate insights into canonical and non-canonical secretory trafficking pathways in neurons to speculate as to the cellular and molecular mechanisms underlying GOSR2 PME. This article is part of a Special Issue entitled: SNARE proteins: a long journey of science in brain physiology and pathology: from molecular.
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Affiliation(s)
- James E C Jepson
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.
| | - Roman Praschberger
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Shyam S Krishnakumar
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK; Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
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13
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Desdentado L, Espert R, Sanz P, Tirapu-Ustarroz J. [Lafora disease: a review of the literature]. Rev Neurol 2019; 68:66-74. [PMID: 30638256 PMCID: PMC6531605] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
INTRODUCTION Lafora disease is autosomal recessive progressive myoclonus epilepsy with late childhood-to teenage-onset caused by loss-of-function mutations in either EPM2A or EPM2B genes encoding laforin or malin, respectively. DEVELOPMENT The main symptoms of Lafora disease, which worsen progressively, are: myoclonus, occipital seizures, generalized tonic-clonic seizures, cognitive decline, neuropsychiatric syptoms and ataxia with a fatal outcome. Pathologically, Lafora disease is characterized by the presence of polyglucosans deposits (named Lafora bodies), in the brain, liver, muscle and sweat glands. Diagnosis of Lafora disease is made through clinical, electrophysiological, histological and genetic findings. Currently, there is no treatment to cure or prevent the development of the disease. Traditionally, antiepileptic drugs are used for the management of myoclonus and seizures. However, patients become drug-resistant after the initial stage. CONCLUSIONS Lafora disease is a rare pathology that has serious consequences for patients and their caregivers despite its low prevalence. Therefore, continuing research in order to clarify the underlying mechanisms and hopefully developing new palliative and curative treatments for the disease is necessary.
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Affiliation(s)
- L Desdentado
- Hospital Clinico Universitario de Valencia, 46010 Valencia, Espana
| | - R Espert
- Hospital Clinico Universitario de Valencia, 46010 Valencia, Espana
- Universidad de Valencia, 46071 Valencia, Espana
| | - P Sanz
- Instituto de Biomedicina de Valencia, 46010 Valencia, Venezuela
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14
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Brewer MK, Grossman TR, McKnight TR, Goldberg YP, Landy H, Gentry MS. The 4th International Lafora Epilepsy Workshop: Shifting paradigms, paths to treatment, and hope for patients. Epilepsy Behav 2019; 90:284-286. [PMID: 30528121 PMCID: PMC6457339 DOI: 10.1016/j.yebeh.2018.11.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022]
Affiliation(s)
- M. Kathryn Brewer
- Department of Molecular and Cellular Biochemistry, Epilepsy and Brain Metabolism Alliance, Lafora Epilepsy Cure Initiative, and Epilepsy Research Center, University of Kentucky College of Medicine, Lexington, KY, 40536 USA
| | | | | | | | - Hal Landy
- Valerion Therapeutics, Concord, MA 01742, USA
| | - Matthew S. Gentry
- Department of Molecular and Cellular Biochemistry, Epilepsy and Brain Metabolism Alliance, Lafora Epilepsy Cure Initiative, and Epilepsy Research Center, University of Kentucky College of Medicine, Lexington, KY, 40536 USA,Corresponding author: 741 S. Limestone, BBSRB, Room 177, Lexington, KY 40536; ; 859-323-8482
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15
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Abstract
Lafora's disease is a neurodegenerative disorder caused by recessive loss-of-function mutations in the EPM2A (laforin glycogen phosphatase) or EPM2B (malin E3 ubiquitin ligase) genes. Neuropathology is characterized by malformed precipitated glycogen aggregates termed Lafora bodies. Asymptomatic until adolescence, patients undergo first insidious then rapid progressive myoclonus epilepsy toward a vegetative state and death within a decade. Laforin and malin interact to regulate glycogen phosphorylation and chain length pattern, the latter critical to glycogen's solubility. Significant gaps remain in precise mechanistic understanding. However, demonstration that partial reduction in brain glycogen synthesis near-completely prevents the disease in its genetic animal models opens a direct present path to therapy.
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Affiliation(s)
- Brandy Verhalen
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Susan Arnold
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Berge A. Minassian
- Division of Neurology, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, United States,Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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16
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Julkunen P, Löfberg O, Kallioniemi E, Hyppönen J, Kälviäinen R, Mervaala E. Abnormal motor cortical adaptation to external stimulus in Unverricht-Lundborg disease (progressive myoclonus type 1, EPM1). J Neurophysiol 2018; 120:617-623. [PMID: 29742025 DOI: 10.1152/jn.00063.2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unverricht-Lundborg disease (EPM1) is associated with progressive functional and anatomic changes in the thalamus and motor cortex. The neurophysiological mechanisms behind the impaired thalamocortical system were studied through short-term adaptation of the motor cortex to transcranial magnetic stimulation (TMS) via repetition suppression (RS) phenomenon. RS is considered to be related to neural processing of external stimuli. We hypothesized that this neural processing is progressively impaired in EPM1 from adolescence to adulthood. Eight adult patients with EPM1 (age: 40 ± 13 yr), six adolescent patients with EPM1 (age: 16 ± 1 yr), and ten adult controls (age: 35 ± 12 yr) were studied using navigated TMS and RS study protocol including trains of four repeated stimuli with intertrain interval of 20 s and interstimulus interval of 1 s. Changes in RS were investigated from adolescence to adulthood in EPM1 by comparing with adult controls. In controls, the RS was seen as 50-55% reduction in motor response amplitudes to TMS after the first stimulus. RS was mild or missing in EPM1. RS from first to second stimulus within the stimulus trains was significantly stronger in adolescent patients than in adult patients ( P = 0.046). Abnormal RS correlated with the myoclonus severity of the patients. In agreement with our hypothesis, neural processing of external stimuli is progressively impaired in EPM1 possibly due to anatomically impaired thalamocortical system or inhibitory tonus preventing sufficient adaptive reactiveness to stimuli. Our results suggest that RS abnormality might be used as a biomarker in the therapeutic trials for myoclonus. NEW & NOTEWORTHY Unverricht-Lundborg disease (EPM1) is associated with impaired thalamocortical function, which we studied in 8 adult and 6 adolescent patients and in 10 adult controls through repetition suppression (RS) of the motor cortex. We hypothesized that neural processing is progressively impaired in EPM1 from adolescence to adulthood. RS was normal in controls, whereas it was mild or missing in EPM1. Stronger RS was seen in adolescent patients than in adult patients correlating with the myoclonus severity.
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Affiliation(s)
- Petro Julkunen
- Department of Clinical Neurophysiology, Kuopio University Hospital , Kuopio , Finland.,Department of Applied Physics, University of Eastern Finland , Kuopio , Finland
| | - Olli Löfberg
- Department of Clinical Neurophysiology, Kuopio University Hospital , Kuopio , Finland
| | - Elisa Kallioniemi
- Department of Clinical Neurophysiology, Kuopio University Hospital , Kuopio , Finland.,Department of Clinical Radiology, Kuopio University Hospital , Kuopio , Finland
| | - Jelena Hyppönen
- Department of Clinical Neurophysiology, Kuopio University Hospital , Kuopio , Finland
| | - Reetta Kälviäinen
- Department of Neurology, Kuopio Epilepsy Center, Kuopio University Hospital , Kuopio , Finland.,Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland , Kuopio , Finland
| | - Esa Mervaala
- Department of Clinical Neurophysiology, Kuopio University Hospital , Kuopio , Finland.,Department of Clinical Neurophysiology, Institute of Clinical Medicine, University of Eastern Finland, Kuopio, Finland
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17
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Praschberger R, Lowe SA, Malintan NT, Giachello CNG, Patel N, Houlden H, Kullmann DM, Baines RA, Usowicz MM, Krishnakumar SS, Hodge JJL, Rothman JE, Jepson JEC. Mutations in Membrin/GOSR2 Reveal Stringent Secretory Pathway Demands of Dendritic Growth and Synaptic Integrity. Cell Rep 2017; 21:97-109. [PMID: 28978487 PMCID: PMC5640804 DOI: 10.1016/j.celrep.2017.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 08/17/2017] [Accepted: 09/01/2017] [Indexed: 11/16/2022] Open
Abstract
Mutations in the Golgi SNARE (SNAP [soluble NSF attachment protein] receptor) protein Membrin (encoded by the GOSR2 gene) cause progressive myoclonus epilepsy (PME). Membrin is a ubiquitous and essential protein mediating ER-to-Golgi membrane fusion. Thus, it is unclear how mutations in Membrin result in a disorder restricted to the nervous system. Here, we use a multi-layered strategy to elucidate the consequences of Membrin mutations from protein to neuron. We show that the pathogenic mutations cause partial reductions in SNARE-mediated membrane fusion. Importantly, these alterations were sufficient to profoundly impair dendritic growth in Drosophila models of GOSR2-PME. Furthermore, we show that Membrin mutations cause fragmentation of the presynaptic cytoskeleton coupled with transsynaptic instability and hyperactive neurotransmission. Our study highlights how dendritic growth is vulnerable even to subtle secretory pathway deficits, uncovers a role for Membrin in synaptic function, and provides a comprehensive explanatory basis for genotype-phenotype relationships in GOSR2-PME.
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Affiliation(s)
- Roman Praschberger
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Simon A Lowe
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, UK
| | - Nancy T Malintan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Carlo N G Giachello
- Faculty of Biology, Medicine, and Health, Division of Neuroscience & Experimental Psychology, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Nian Patel
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Molecular Neuroscience, UCL Institute of Neurology, London, UK
| | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Richard A Baines
- Faculty of Biology, Medicine, and Health, Division of Neuroscience & Experimental Psychology, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Maria M Usowicz
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, UK
| | - Shyam S Krishnakumar
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK; Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - James J L Hodge
- School of Physiology, Pharmacology, and Neuroscience, University of Bristol, Bristol, UK
| | - James E Rothman
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK; Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - James E C Jepson
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK.
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18
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Abstract
A 17-year-old female, of consanguineous parents, presented with a history of seizures and cognitive decline since the age of 12 years. She had absence, focal dyscognitive, generalized myoclonic, and generalized tonic-clonic seizures, all of which were drug resistant. The diagnosis of Lafora body disease was made based on a compatible clinical, EEG, seizure semiology picture and a disease-causing homozygous mutation in the EPM2A gene. A vagus nerve stimulator (VNS) was inserted and well tolerated with a steady decrease and then stabilization in seizure frequency during the six months following insertion (months 1-6). At follow-up, at 12 months after VNS insertion, there was a persistent improvement. Seizure frequency during months 7-12, compared to pre-VNS, was documented as follows: the absence seizures observed by the family had decreased from four episodes per month to 0 per month, the focal dyscognitive seizures from 300 episodes per month to 90 per month, the generalized myoclonic seizures from 90 clusters per month to eight per month, and the generalized tonic-clonic seizures from 30 episodes per month to 1.5 per month on average. To our knowledge, this is the second case reported in the literature showing efficacy of VNS in the management of seizures in Lafora body disease.
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19
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Abstract
The history of the progressive myoclonus epilepsies (PMEs) spans more than a century. However, the recent history of PMEs begins with a consensus statement published in the wake of the Marseille PME workshop in 1989 (Marseille Consensus Group, 1990). This consensus helped define the various types of PME known at the time and set the agenda for a new era of genetic research which soon lead to the discovery of many PME genes. Prior to the Marseille meeting, and before the molecular era, there had been much confusion and controversy. Because investigators had but limited and biased experience with these rare disorders due to the uneven, skewed distribution of PMEs around the world, opinions and nosologies were based on local expertise which did not match well with the experiences of other researchers and clinicians. The three major areas of focus included: (1) the nature and limits of the concept of PME in varying scopes, which was greatly debated; (2) the description of discrete clinical entities by clinicians; and (3) the description of markers (pathological, biological, neurophysiological, etc.) which could lead to a precise diagnosis of a given PME type, with, in the best cases, a reliable correlation with clinical findings. In this article, we shall also examine the breakthroughs achieved in the wake of the 1989 Marseille meeting and recent history in the field, following the identification of several PME genes. As in other domains, the molecular and genetic approach has challenged some established concepts and has led to the description of new PME types. However, as may already be noted, this approach has also confirmed the existence of the major, established types of PME, which can now be considered as true diseases.
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Affiliation(s)
- Pierre Genton
- Centre Saint-Paul - Hospital Henri-Gastaut, 300 Bd De Sainte Marguerite, 13009 Marseille, France
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, “G. Gaslini” Institute, Genova, Italy
| | - Berge A. Minassian
- The Hospital for Sick Children and University of Toronto, 555 University Avenue, Toronto, Ontario, M5G 1X8, Canada
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20
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Abstract
Action myoclonus-renal failure syndrome (AMRF) is an autosomal recessive progressive myoclonus epilepsy (PME) associated with renal dysfunction that appears in the second or third decade of life and that is caused by loss-of-function mutations in the SCARB2 gene encoding lysosomal integral membrane protein type 2 (LIMP2). Recent reports have documented cases with PME associated with SCARB2 mutations without renal compromise. Additional neurological features can be demyelinating peripheral neuropathy, hearing loss and dementia. The course of the disease in relentlessly progressive. In this paper we provide an updated overview of the clinical and genetic features of SCARB2-related PME and on the functions of the LIMP2 protein.
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Affiliation(s)
- Leanne Dibbens
- Epilepsy Research Group, School of Pharmacy and Medical Sciences, University of South Australia, and Sansom Institute for Health Research, South Australia, Australia
| | | | - Paul Saftig
- Biochemical Institute, Christian-Albrechts-University Kiel, Germany
| | - Guido Rubboli
- Danish Epilepsy Center, Filadelfia/University of Copenhagen, Dianalund, Denmark, IRCCS, Institute of Neurologicak Sciences, Bellaria Hospital, Bologna, Italy
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21
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Walker MA, Mohler KP, Hopkins KW, Oakley DH, Sweetser DA, Ibba M, Frosch MP, Thibert RL. Novel Compound Heterozygous Mutations Expand the Recognized Phenotypes of FARS2-Linked Disease. J Child Neurol 2016; 31:1127-37. [PMID: 27095821 PMCID: PMC4981184 DOI: 10.1177/0883073816643402] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 03/03/2016] [Indexed: 12/28/2022]
Abstract
Mutations in mitochondrial aminoacyl-tRNA synthetases are an increasingly recognized cause of human diseases, often arising in individuals with compound heterozygous mutations and presenting with system-specific phenotypes, frequently neurologic. FARS2 encodes mitochondrial phenylalanyl transfer ribonucleic acid (RNA) synthetase (mtPheRS), perturbations of which have been reported in 6 cases of an infantile, lethal disease with refractory epilepsy and progressive myoclonus. Here the authors report the case of juvenile onset refractory epilepsy and progressive myoclonus with compound heterozygous FARS2 mutations. The authors describe the clinical course over 6 years of care at their institution and diagnostic studies including electroencephalogram (EEG), brain magnetic resonance imaging (MRI), serum and cerebrospinal fluid analyses, skeletal muscle biopsy histology, and autopsy gross and histologic findings, which include features shared with Alpers-Huttenlocher syndrome, Leigh syndrome, and a previously published case of FARS2 mutation associated infantile onset disease. The authors also present structure-guided analysis of the relevant mutations based on published mitochondrial phenylalanyl transfer RNA synthetase and related protein crystal structures as well as biochemical analysis of the corresponding recombinant mutant proteins.
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Affiliation(s)
- Melissa A Walker
- Division of Child Neurology, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA
| | - Kyle P Mohler
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Kyle W Hopkins
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Derek H Oakley
- Division of Neuropathology, Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - David A Sweetser
- Department of Medical Genetics, Massachusetts General Hospital, Boston, MA, USA
| | - Michael Ibba
- Department of Microbiology, Ohio State University, Columbus, OH, USA
| | - Matthew P Frosch
- Division of Neuropathology, Department of Pathology, Massachusetts General Hospital, Boston, MA, USA
| | - Ronald L Thibert
- Department of Neurology, Division of Child Neurology, Massachusetts General Hospital, Boston, MA, USA
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Praschberger R, Balint B, Mencacci NE, Hersheson J, Rubio-Agusti I, Kullmann DM, Bettencourt C, Bhatia K, Houlden H. Expanding the Phenotype and Genetic Defects Associated with the GOSR2 Gene. Mov Disord Clin Pract 2015; 2:271-273. [PMID: 30363482 DOI: 10.1002/mdc3.12190] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 03/23/2015] [Accepted: 03/25/2015] [Indexed: 01/24/2023] Open
Abstract
Background The homozygous missense mutation c.430G>T (p.G144W) in the GOSR2 gene has been repeatedly shown to cause progressive myoclonus epilepsy/ataxia. Thus far, no other disease associated GOSR2 mutation has been reported. Methods From epilepsy, movement disorder and genetic clinics 43 patients suffering from progressive myoclonus epilepsy/ataxia were screened for defects in GOSR2, SCARB2 and CSTB. Results A 61-year-old female patient suffering from progressive myoclonus epilepsy was found to be compound heterozygous for the known c.430G>T and a novel c.491_493delAGA (p.K164del) GOSR2 mutation. This is so far the oldest GOSR2 patient and her disease course seems overall milder. Conclusions This finding further highlights the GOSR2 gene as a cause of progressive myoclonus epilepsy and expands the genotype for a potentially weaker disease allele.
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Affiliation(s)
- Roman Praschberger
- Department of Molecular Neuroscience UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery (NHNN) London United Kingdom.,Department of Clinical and Experimental Epilepsy UCL Institute of Neurology London United Kingdom
| | - Bettina Balint
- Sobell Department of Motor Neuroscience and Movement Disorders UCL Institute of Neurology London United Kingdom.,Department of Neurology University Hospital Heidelberg Heidelberg Germany
| | - Niccolo E Mencacci
- Department of Molecular Neuroscience UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery (NHNN) London United Kingdom
| | - Joshua Hersheson
- Department of Molecular Neuroscience UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery (NHNN) London United Kingdom
| | | | - Dimitri M Kullmann
- Department of Clinical and Experimental Epilepsy UCL Institute of Neurology London United Kingdom
| | - Conceição Bettencourt
- Department of Molecular Neuroscience UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery (NHNN) London United Kingdom
| | - Kailash Bhatia
- Sobell Department of Motor Neuroscience and Movement Disorders UCL Institute of Neurology London United Kingdom
| | - Henry Houlden
- Department of Molecular Neuroscience UCL Institute of Neurology and The National Hospital for Neurology and Neurosurgery (NHNN) London United Kingdom
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23
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Fu YJ, Aida I, Tada M, Tada M, Toyoshima Y, Takeda S, Nakajima T, Naito H, Nishizawa M, Onodera O, Kakita A, Takahashi H. Progressive myoclonus epilepsy: extraneuronal brown pigment deposition and system neurodegeneration in the brains of Japanese patients with novel SCARB2 mutations. Neuropathol Appl Neurobiol 2014; 40:551-63. [PMID: 23659519 DOI: 10.1111/nan.12057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2012] [Accepted: 04/30/2013] [Indexed: 11/29/2022]
Abstract
AIMS Mutations in the SCARB2 gene cause a rare autosomal recessive disease, progressive myoclonus epilepsy (PME) with or without renal failure, the former also being designated action myoclonus-renal failure syndrome. Although reported cases have been accumulating, only a few have described its neuropathology. We studied two Japanese patients with PME without renal failure, in whom the ages at onset and disease durations were 45 and 20 years, and 14 and 8.5 years respectively. METHODS Sequencing and restriction analysis of the SCARB2 gene and neuropathological examination with immunohistochemistry were performed. RESULTS Gene analyses revealed novel homozygous frameshift and nonsense mutations in the SCARB2 gene. Both cases exhibited deposition of brown pigment in the brain, especially the cerebellar and cerebral cortices. Ultrastructurally, the pigment granules were localized in astrocytes. Neuronal loss and gliosis were also evident in the brain, including the pallidoluysian and cerebello-olivary systems. The spinal cord was also affected. Such changes were less severe in one patient with late-onset disease than in the other patient with early-onset disease. In brain and kidney sections, immunostaining with an antibody against the C-terminus of human SCARB2 revealed decreased levels and no expression of the protein respectively. CONCLUSIONS The frameshift mutation detected in the patient with late-onset disease is a hitherto undescribed, unique type of SCARB2 gene mutation. The present two patients are the first reported to have clearly demonstrated both extraneuronal brown pigment deposition and system neurodegeneration as neuropathological features of PME with SCARB2 mutations.
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Affiliation(s)
- Yong-Juan Fu
- Department of Pathology, Brain Research Institute, University of Niigata, Niigata, Japan
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24
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Ganos C, Kassavetis P, Erro R, Edwards MJ, Rothwell J, Bhatia KP. The role of the cerebellum in the pathogenesis of cortical myoclonus. Mov Disord 2014; 29:437-43. [PMID: 24634361 DOI: 10.1002/mds.25867] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 02/09/2014] [Accepted: 02/17/2014] [Indexed: 12/26/2022] Open
Abstract
The putative involvement of the cerebellum in the pathogenesis of cortical myoclonic syndromes has been long hypothesized, as neuropathological changes in patients with cortical myoclonus have most commonly been found in the cerebellum rather than in the suspected culprit, the primary somatosensory cortex. A model of increased cortical excitability due to loss of cerebellar inhibitory control via cerebello-thalamo-cortical connections has been proposed, but evidence remains equivocal. Here, we explore this hypothesis by examining syndromes that present with cortical myoclonus and ataxia. We first describe common clinical characteristics and underlying neuropathology. We critically view information on cerebellar physiology with regard to motorcortical output and compare findings between hypothesized and reported neurophysiological changes in conditions with cortical myoclonus and ataxia. We synthesize knowledge and focus on neurochemical changes in these conditions. Finally, we propose that the combination of alterations in inhibitory neurotransmission and the presence of cerebellar pathology are important elements in the pathogenesis of cortical myoclonus.
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Affiliation(s)
- Christos Ganos
- Sobell Department of Motor Neuroscience and Movement Disorders, University College London (UCL) Institute of Neurology, London, United Kingdom; Department of Neurology, University Medical Centre Hamburg-Eppendorf (UKE), Hamburg, Germany; Department of Paediatric and Adult Movement Disorders and Neuropsychiatry, Institute of Neurogenetics, University of Lübeck, Lübeck, Germany
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25
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Hagen MC, Murrell JR, Delisle MB, Andermann E, Andermann F, Guiot MC, Ghetti B. Encephalopathy with neuroserpin inclusion bodies presenting as progressive myoclonus epilepsy and associated with a novel mutation in the Proteinase Inhibitor 12 gene. Brain Pathol 2011; 21:575-82. [PMID: 21435071 PMCID: PMC3709456 DOI: 10.1111/j.1750-3639.2011.00481.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2010] [Accepted: 01/20/2011] [Indexed: 11/28/2022] Open
Abstract
Neuroserpin encephalopathy is an autosomal-dominant degenerative disease associated with mutations in the Proteinase Inhibitor 12 (PI12) gene. A 26-year-old male presented with progressive myoclonus epilepsy and declining mental status. He had failed in university studies because of impaired attention, memory and concentration. Generalized seizures started to occur approximately once a month, and he developed myoclonus and progressive gait disturbances. Neuroimaging revealed mild atrophy and multiple periventricular white matter lesions, consistent with demyelination. He progressively declined and died at age 34. Neuropathologic examination revealed widespread involvement of the cerebral cortex by numerous round eosinophilic inclusions in neuronal perikarya and neuropil, predominantly within the deep cortical layers. Numerous inclusions were also found in the basal ganglia, thalamus, hippocampus, brain stem, spinal gray matter, and dorsal root ganglia. They were essentially absent from the cerebellum. The inclusions were immunopositive for antibodies raised against neuroserpin. The white matter lesions showed histologic features compatible with multiple sclerosis. Genetic analysis revealed a nucleotide substitution in codon 47 in one allele of the PI12 gene, resulting in a proline for leucine amino acid substitution (L47P). In summary, we report a case of neuroserpin encephalopathy associated with a novel PI12 mutation and complicated by coexistent multiple sclerosis.
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Affiliation(s)
- Matthew C Hagen
- Department ofPathology and Laboratory Medicine, IndianaUniversity School of Medicine, Van Nuys Medical Science Building, Room A128, 635 Barnhill Drive, Indianapolis, IN 46202-5120, USA.
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26
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Andrade DM, Turnbull J, Minassian BA. Lafora disease, seizures and sugars. Acta Myol 2007; 26:83-6. [PMID: 17915579 PMCID: PMC2949329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Lafora disease (LD) is the most severe form of Progressive Myoclonus Epilepsy with teenage onset. It has an autosomal recessive mode of inheritance and is almost universally fatal by the second or third decade of life. To date, there is no prevention or cure. In the last decade, with the identification of the genes responsible for this disease, much knowledge has been gained with the potential for the future development of effective treatment. This review will briefly address clinical issues and will focus on the molecular aspects of the disease.
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Affiliation(s)
- D M Andrade
- Division of Neurology, Krembil Neuroscience Centre, University of Toronto, Toronto Western Hospital, Toronto, Canada
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27
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El-Shanti H, Daoud A, Sadoon AA, Leal SM, Chen S, Lee K, Spiegel R. A distinct autosomal recessive ataxia maps to chromosome 12 in an inbred family from Jordan. Brain Dev 2006; 28:353-7. [PMID: 16376507 PMCID: PMC6143173 DOI: 10.1016/j.braindev.2005.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2005] [Revised: 11/04/2005] [Accepted: 11/09/2005] [Indexed: 11/17/2022]
Abstract
Autosomal recessive ataxias are a heterogeneous group of rare disorders characterized by early onset ataxia associated with neurologic, ophthalmologic or systemic signs. The ataxias associated with myoclonus, epilepsy and progressive neurological degeneration are usually included with the progressive myoclonus epilepsies, one of which is Unverricht-Lundborg disease. We identified four siblings with ataxia, juvenile onset progressive action tremor and atonic seizures from a Jordanian family. The mode of inheritance of this syndrome is autosomal recessive. We performed a genome-wide screen for linkage and fine mapped the region that contains the disease locus. The four affected siblings have ataxia noted at the onset of walking with dysarthria and bulbar features, but no cerebellar hypoplasia on MRI. They all developed a fine tremor that progressed to a coarse action tremor, as well as atonic seizures. Treatment with valproate fully controlled the seizures and improved the tremor, but did not change the course of the ataxia. We mapped the gene responsible for this disorder to the pericentromeric region of chromosome 12. A recently described autosomal recessive variant of Unverricht-Lundborg disease also maps to the same region. We discuss the similarities and differences between our family and the family with the Unverricht-Lundborg disease variant.
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Affiliation(s)
- Hatem El-Shanti
- Department of Pediatrics, Division of Medical Genetics, University of Iowa, UIHC, 2615 JCP, Iowa City, IA 52242, USA.
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