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Ng ACH, Chahine M, Scantlebury MH, Appendino JP. Channelopathies in epilepsy: an overview of clinical presentations, pathogenic mechanisms, and therapeutic insights. J Neurol 2024; 271:3063-3094. [PMID: 38607431 DOI: 10.1007/s00415-024-12352-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
Pathogenic variants in genes encoding ion channels are causal for various pediatric and adult neurological conditions. In particular, several epilepsy syndromes have been identified to be caused by specific channelopathies. These encompass a spectrum from self-limited epilepsies to developmental and epileptic encephalopathies spanning genetic and acquired causes. Several of these channelopathies have exquisite responses to specific antiseizure medications (ASMs), while others ASMs may prove ineffective or even worsen seizures. Some channelopathies demonstrate phenotypic pleiotropy and can cause other neurological conditions outside of epilepsy. This review aims to provide a comprehensive exploration of the pathophysiology of seizure generation, ion channels implicated in epilepsy, and several genetic epilepsies due to ion channel dysfunction. We outline the clinical presentation, pathogenesis, and the current state of basic science and clinical research for these channelopathies. In addition, we briefly look at potential precision therapy approaches emerging for these disorders.
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Affiliation(s)
- Andy Cheuk-Him Ng
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Division of Neurology, Department of Pediatrics, Faculty of Medicine and Dentistry, University of Alberta and Stollery Children's Hospital, Edmonton, AB, Canada
| | - Mohamed Chahine
- Department of Medicine, Faculty of Medicine, Université Laval, Quebec City, QC, Canada
- CERVO, Brain Research Centre, Quebec City, Canada
| | - Morris H Scantlebury
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, Calgary, Canada
| | - Juan P Appendino
- Clinical Neuroscience and Pediatric Neurology, Department of Pediatrics, Cumming School of Medicine, Alberta Children's Hospital, University of Calgary, 28 Oki Drive NW, Calgary, AB, T3B 6A8, Canada.
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4
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Salpietro V, Maroofian R, Zaki MS, Wangen J, Ciolfi A, Barresi S, Efthymiou S, Lamaze A, Aughey GN, Al Mutairi F, Rad A, Rocca C, Calì E, Accogli A, Zara F, Striano P, Mojarrad M, Tariq H, Giacopuzzi E, Taylor JC, Oprea G, Skrahina V, Rehman KU, Abd Elmaksoud M, Bassiony M, El Said HG, Abdel-Hamid MS, Al Shalan M, Seo G, Kim S, Lee H, Khang R, Issa MY, Elbendary HM, Rafat K, Marinakis NM, Traeger-Synodinos J, Ververi A, Sourmpi M, Eslahi A, Khadivi Zand F, Beiraghi Toosi M, Babaei M, Jackson A, Bertoli-Avella A, Pagnamenta AT, Niceta M, Battini R, Corsello A, Leoni C, Chiarelli F, Dallapiccola B, Faqeih EA, Tallur KK, Alfadhel M, Alobeid E, Maddirevula S, Mankad K, Banka S, Ghayoor-Karimiani E, Tartaglia M, Chung WK, Green R, Alkuraya FS, Jepson JEC, Houlden H. Bi-allelic genetic variants in the translational GTPases GTPBP1 and GTPBP2 cause a distinct identical neurodevelopmental syndrome. Am J Hum Genet 2024; 111:200-210. [PMID: 38118446 PMCID: PMC10806450 DOI: 10.1016/j.ajhg.2023.11.012] [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: 05/15/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/22/2023] Open
Abstract
The homologous genes GTPBP1 and GTPBP2 encode GTP-binding proteins 1 and 2, which are involved in ribosomal homeostasis. Pathogenic variants in GTPBP2 were recently shown to be an ultra-rare cause of neurodegenerative or neurodevelopmental disorders (NDDs). Until now, no human phenotype has been linked to GTPBP1. Here, we describe individuals carrying bi-allelic GTPBP1 variants that display an identical phenotype with GTPBP2 and characterize the overall spectrum of GTP-binding protein (1/2)-related disorders. In this study, 20 individuals from 16 families with distinct NDDs and syndromic facial features were investigated by whole-exome (WES) or whole-genome (WGS) sequencing. To assess the functional impact of the identified genetic variants, semi-quantitative PCR, western blot, and ribosome profiling assays were performed in fibroblasts from affected individuals. We also investigated the effect of reducing expression of CG2017, an ortholog of human GTPBP1/2, in the fruit fly Drosophila melanogaster. Individuals with bi-allelic GTPBP1 or GTPBP2 variants presented with microcephaly, profound neurodevelopmental impairment, pathognomonic craniofacial features, and ectodermal defects. Abnormal vision and/or hearing, progressive spasticity, choreoathetoid movements, refractory epilepsy, and brain atrophy were part of the core phenotype of this syndrome. Cell line studies identified a loss-of-function (LoF) impact of the disease-associated variants but no significant abnormalities on ribosome profiling. Reduced expression of CG2017 isoforms was associated with locomotor impairment in Drosophila. In conclusion, bi-allelic GTPBP1 and GTPBP2 LoF variants cause an identical, distinct neurodevelopmental syndrome. Mutant CG2017 knockout flies display motor impairment, highlighting the conserved role for GTP-binding proteins in CNS development across species.
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Affiliation(s)
- Vincenzo Salpietro
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Maha S Zaki
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Jamie Wangen
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Andrea Ciolfi
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Sabina Barresi
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Stephanie Efthymiou
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Angelique Lamaze
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK; Institute of Neuro- and Behavioral Biology, Westfälische Wilhelms University, Münster, Germany
| | - Gabriel N Aughey
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Fuad Al Mutairi
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | | | - Clarissa Rocca
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Elisa Calì
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK
| | - Andrea Accogli
- Division of Medical Genetics, Department of Pediatrics, McGill University, Montreal, Canada
| | - Federico Zara
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, Genoa, Italy; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy; Unit of Pediatric Neurology, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Majid Mojarrad
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Huma Tariq
- Health Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan
| | - Edoardo Giacopuzzi
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK; Genomics Research Centre, Human Technopole, Milan, Italy; Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Jenny C Taylor
- National Institute for Health Research Oxford Biomedical Research Centre, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | | | | | | | - Marwa Abd Elmaksoud
- Neurology Unit, Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Mahmoud Bassiony
- Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Huda G El Said
- Department of Family Health, High Institute of Public Health, University of Alexandria, Alexandria, Egypt
| | - Mohamed S Abdel-Hamid
- Department of Medical Molecular Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Maha Al Shalan
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia
| | | | | | - Hane Lee
- 3billion, Inc, Seoul, South Korea
| | | | - Mahmoud Y Issa
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Hasnaa M Elbendary
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Karima Rafat
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, National Research Centre, Cairo, Egypt
| | - Nikolaos M Marinakis
- Laboratory of Medical Genetics, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Joanne Traeger-Synodinos
- Laboratory of Medical Genetics, St. Sophia's Children's Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Athina Ververi
- Genetics Unit, Department of Obstetrics & Gynaecology, Aristotle University of Thessaloniki, Papageorgiou General Hospital, Thessaloniki, Greece
| | | | - Atieh Eslahi
- Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Masshad, Iran; Student Research Committee, Faculty of Medicine, Mashhad University of Medical Sciences, Masshad, Iran
| | | | - Mehran Beiraghi Toosi
- Pediatric Neurology Department, Ghaem Hospital, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Meisam Babaei
- Department of Pediatrics, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Adam Jackson
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester M13 9WL, UK
| | | | | | - Marcello Niceta
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Roberta Battini
- Department of Developmental Neuroscience, IRCCS Stella Maris Foundation, 56128 Pisa, Italy; Department of Clinical and Experimental Medicine, University of Pisa, 56126 Pisa, Italy
| | - Antonio Corsello
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Chiara Leoni
- Center for Rare Diseases and Birth Defects, Department of Women and Child Health and Public Health, Fondazione Policlinico Universitario A. Gemelli IRCCS, 00168 Rome, Italy
| | | | - Bruno Dallapiccola
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Eissa Ali Faqeih
- Unit of Medical Genetics, Children's Specialist Hospital, King Fahad Medical City, Riyadh, Saudi Arabia
| | | | - Majid Alfadhel
- Genetic and Precision Medicine Department, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; King Abdullah International Medical Research Center (KAIMRC), King Saud bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGHA), Riyadh, Saudi Arabia; College of Medicine, King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia
| | - Eman Alobeid
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Sateesh Maddirevula
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Kshitij Mankad
- Department of Neuroradiology, Great Ormond Street Hospital, London, UK
| | - Siddharth Banka
- Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Health Innovation Manchester, Manchester M13 9WL, UK
| | - Ehsan Ghayoor-Karimiani
- Genetics Research Centre, Molecular and Clinical Sciences Institute, University of London, St George's, Cranmer Terrace, London SW17 0RE, UK
| | - Marco Tartaglia
- Molecular Genetics and Functional Genomics, Ospedale Pediatrico Bambino Gesù, IRCCS, 00146 Rome, Italy
| | - Wendy K Chung
- Department of Pediatrics, Boston Children's Hospital Harvard Medical School, Boston, MA 02115, USA
| | - Rachel Green
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Fowzan S Alkuraya
- Department of Genetics, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - James E C Jepson
- Department of Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Henry Houlden
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, London, UK.
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Zhao R, Qasim A, Sophanpanichkul P, Dai H, Nayak M, Sher I, Chill J, Goldstein SAN. Selective block of human Kv1.1 channels and an epilepsy-associated gain-of-function mutation by AETX-K peptide. FASEB J 2024; 38:e23381. [PMID: 38102952 PMCID: PMC10754259 DOI: 10.1096/fj.202302061r] [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: 10/10/2023] [Revised: 11/11/2023] [Accepted: 12/05/2023] [Indexed: 12/17/2023]
Abstract
Dysfunction of the human voltage-gated K+ channel Kv1.1 has been associated with epilepsy, multiple sclerosis, episodic ataxia, myokymia, and cardiorespiratory dysregulation. We report here that AETX-K, a sea anemone type I (SAK1) peptide toxin we isolated from a phage display library, blocks Kv1.1 with high affinity (Ki ~ 1.6 pM) and notable specificity, inhibiting other Kv channels we tested a million-fold less well. Nuclear magnetic resonance (NMR) was employed both to determine the three-dimensional structure of AETX-K, showing it to employ a classic SAK1 scaffold while exhibiting a unique electrostatic potential surface, and to visualize AETX-K bound to the Kv1.1 pore domain embedded in lipoprotein nanodiscs. Study of Kv1.1 in Xenopus oocytes with AETX-K and point variants using electrophysiology demonstrated the blocking mechanism to employ a toxin-channel configuration we have described before whereby AETX-K Lys23 , two positions away on the toxin interaction surface from the classical blocking residue, enters the pore deeply enough to interact with K+ ions traversing the pathway from the opposite side of the membrane. The mutant channel Kv1.1-L296 F is associated with pharmaco-resistant multifocal epilepsy in infants because it significantly increases K+ currents by facilitating opening and slowing closure of the channels. Consistent with the therapeutic potential of AETX-K for Kv1.1 gain-of-function-associated diseases, AETX-K at 4 pM decreased Kv1.1-L296 F currents to wild-type levels; further, populations of heteromeric channels formed by co-expression Kv1.1 and Kv1.2, as found in many neurons, showed a Ki of ~10 nM even though homomeric Kv1.2 channels were insensitive to the toxin (Ki > 2000 nM).
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Affiliation(s)
- Ruiming Zhao
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Arwa Qasim
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Punyanuch Sophanpanichkul
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Hui Dai
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Maha Nayak
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
| | - Inbal Sher
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Jordan Chill
- Department of Chemistry, Bar Ilan University, Ramat Gan, 52900, Israel
| | - Steve A. N. Goldstein
- Departments of Pediatrics, Physiology & Biophysics, and Pharmaceutical Sciences, Susan and Henry Samueli College of Health Sciences, University of California, Irvine, Irvine, CA 92697, USA
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