1
|
Berg AT, Thompson CH, Myers LS, Anderson E, Evans L, Kaiser AJE, Paltell K, Nili AN, DeKeyser JML, Abramova TV, Nesbitt G, Egan SM, Vanoye CG, George AL. Expanded clinical phenotype spectrum correlates with variant function in SCN2A-related disorders. Brain 2024; 147:2761-2774. [PMID: 38651838 PMCID: PMC11292900 DOI: 10.1093/brain/awae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 03/04/2024] [Accepted: 03/24/2024] [Indexed: 04/25/2024] Open
Abstract
SCN2A-related disorders secondary to altered function in the voltage-gated sodium channel Nav1.2 are rare, with clinically heterogeneous expressions that include epilepsy, autism and multiple severe to profound impairments and other conditions. To advance understanding of the clinical phenotypes and their relationship to channel function, 81 patients (36 female, 44%, median age 5.4 years) with 69 unique SCN2A variants were systematically phenotyped and their Nav1.2 channel function systematically assessed. Participants were recruited through the FamileSCN2A Foundation. Primary phenotype (epilepsy of neonatal onset, n = 27; infant onset, n = 18; and later onset n = 24; and autism without seizures, n = 12) was strongly correlated with a non-seizure severity index (P = 0.002), which was based on presence of severe impairments in gross motor, fine motor, communication abilities, gastrostomy tube dependence and diagnosis of cortical visual impairment and scoliosis. Non-seizure severity was greatest in the neonatal-onset group and least in the autism group (P = 0.002). Children with the lowest severity indices were still severely impaired, as reflected by an average Vineland Adaptive Behavior composite score of 49.5 (>3 standard deviations below the norm-referenced mean of the test). Epileptic spasms were significantly more common in infant-onset (67%) than in neonatal (22%) or later-onset (29%) epilepsy (P = 0.007). Primary phenotype was also strongly correlated with variant function (P < 0.0001); gain-of-function and mixed function variants predominated in neonatal-onset epilepsy, shifting to moderate loss of function in infant-onset epilepsy and to severe and complete loss of function in later-onset epilepsy and autism groups. Exploratory cluster analysis identified five groups, representing: (i) primarily later-onset epilepsy with moderate loss-of-function variants and low severity indices; (ii) mostly infant-onset epilepsy with moderate loss-of-function variants but higher severity indices; and (iii) late-onset and autism only, with the lowest severity indices (mostly zero) and severe/complete loss-of-function variants. Two exclusively neonatal clusters were distinguished from each other largely on non-seizure severity scores and secondarily on variant function. The relationship between primary phenotype and variant function emphasizes the role of developmental factors in the differential clinical expression of SCN2A variants based on their effects on Nav1.2 channel function. The non-seizure severity of SCN2A disorders depends on a combination of the age at seizure onset (primary phenotype) and variant function. As precision therapies for SCN2A-related disorders advance towards clinical trials, knowledge of the relationship between variant function and clinical disease expression will be valuable for identifying appropriate patients for these trials and in selecting efficient clinical outcomes.
Collapse
Affiliation(s)
- Anne T Berg
- Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
- FamilieSCN2A Foundation, Longmeadow, MA 10116, USA
| | - Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | | | - Erica Anderson
- Institute for Innovations in Developmental Sciences, Northwestern University, Chicago, IL 60611, USA
| | - Lindsey Evans
- Department of Psychology, Illinois Institute of Technology, Chicago, IL 60616, USA
| | - Ariela J E Kaiser
- Department of Psychology, University of Illinois Chicago, Chicago, IL 60616, USA
| | - Katherine Paltell
- Department of Psychology, University of Illinois Chicago, Chicago, IL 60616, USA
| | - Amanda N Nili
- Department of Medical and Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Jean-Marc L DeKeyser
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Tatiana V Abramova
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | | | - Shawn M Egan
- FamilieSCN2A Foundation, Longmeadow, MA 10116, USA
| | - Carlos G Vanoye
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| |
Collapse
|
2
|
Thompson CH, Potet F, Abramova TV, DeKeyser JM, Ghabra NF, Vanoye CG, Millichap JJ, George AL. Epilepsy-associated SCN2A (NaV1.2) variants exhibit diverse and complex functional properties. J Gen Physiol 2023; 155:e202313375. [PMID: 37578743 PMCID: PMC10424433 DOI: 10.1085/jgp.202313375] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 06/29/2023] [Accepted: 07/25/2023] [Indexed: 08/15/2023] Open
Abstract
Pathogenic variants in voltage-gated sodium (NaV) channel genes including SCN2A, encoding NaV1.2, are discovered frequently in neurodevelopmental disorders with or without epilepsy. SCN2A is also a high-confidence risk gene for autism spectrum disorder (ASD) and nonsyndromic intellectual disability (ID). Previous work to determine the functional consequences of SCN2A variants yielded a paradigm in which predominantly gain-of-function variants cause neonatal-onset epilepsy, whereas loss-of-function variants are associated with ASD and ID. However, this framework was derived from a limited number of studies conducted under heterogeneous experimental conditions, whereas most disease-associated SCN2A variants have not been functionally annotated. We determined the functional properties of SCN2A variants using automated patch-clamp recording to demonstrate the validity of this method and to examine whether a binary classification of variant dysfunction is evident in a larger cohort studied under uniform conditions. We studied 28 disease-associated variants and 4 common variants using two alternatively spliced isoforms of NaV1.2 expressed in HEK293T cells. Automated patch-clamp recording provided a valid high throughput method to ascertain detailed functional properties of NaV1.2 variants with concordant findings for variants that were previously studied using manual patch clamp. Many epilepsy-associated variants in our study exhibited complex patterns of gain- and loss-of-functions that are difficult to classify by a simple binary scheme. The higher throughput achievable with automated patch clamp enables study of variants with greater standardization of recording conditions, freedom from operator bias, and enhanced experimental rigor. This approach offers an enhanced ability to discern relationships between channel dysfunction and neurodevelopmental disorders.
Collapse
Affiliation(s)
- Christopher H. Thompson
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Franck Potet
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Tatiana V. Abramova
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Jean-Marc DeKeyser
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Nora F. Ghabra
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Carlos G. Vanoye
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - John J. Millichap
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Alfred L. George
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| |
Collapse
|
3
|
McKenzie CE, Forster IC, Soh MS, Phillips AM, Bleakley LE, Russ-Hall SJ, Myers KA, Scheffer IE, Reid CA. Cation leak: a common functional defect causing HCN1 developmental and epileptic encephalopathy. Brain Commun 2023; 5:fcad156. [PMID: 37265603 PMCID: PMC10231804 DOI: 10.1093/braincomms/fcad156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 03/27/2023] [Accepted: 05/15/2023] [Indexed: 06/03/2023] Open
Abstract
Pathogenic variants in HCN1 are an established cause of developmental and epileptic encephalopathy (DEE). To date, the stratification of patients with HCN1-DEE based on the biophysical consequence on channel function of a given variant has not been possible. Here, we analysed data from eleven patients carrying seven different de novo HCN1 pathogenic variants located in the transmembrane domains of the protein. All patients were diagnosed with severe disease including epilepsy and intellectual disability. The functional properties of the seven HCN1 pathogenic variants were assessed using two-electrode voltage-clamp recordings in Xenopus oocytes. All seven variants showed a significantly larger instantaneous current consistent with cation leak. The impact of each variant on other biophysical properties was variable, including changes in the half activation voltage and activation and deactivation kinetics. These data suggest that cation leak is an important pathogenic mechanism in HCN1-DEE. Furthermore, published mouse model and clinical case reports suggest that seizures are exacerbated by sodium channel blockers in patients with HCN1 variants that cause cation leak. Stratification of patients based on their 'cation leak' biophysical phenotype may therefore provide key information to guide clinical management of individuals with HCN1-DEE.
Collapse
Affiliation(s)
- Chaseley E McKenzie
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Ian C Forster
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Ming S Soh
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - A Marie Phillips
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
- School of Biosciences, University of Melbourne, Parkville, VIC 3052, Australia
| | - Lauren E Bleakley
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
| | - Sophie J Russ-Hall
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia
| | - Kenneth A Myers
- Department of Pediatrics, Faculty of Medicine, McGill University, Montreal, Montreal, Quebec H4A 3J1, Canada
| | - Ingrid E Scheffer
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC 3052, Australia
- Department of Medicine, Epilepsy Research Centre, University of Melbourne, Austin Health, Heidelberg, VIC 3084, Australia
- Department of Paediatrics, University of Melbourne, Royal Children’s Hospital, Parkville, VIC 3052, Australia
| | - Christopher A Reid
- Correspondence to: Christopher A. Reid The Florey Institute of Neuroscience and Mental Health, University of Melbourne 30 Royal Parade, Parkville, Victoria 3052, Australian E-mail:
| |
Collapse
|
4
|
Johannesen KM, Liu Y, Koko M, Gjerulfsen CE, Sonnenberg L, Schubert J, Fenger CD, Eltokhi A, Rannap M, Koch NA, Lauxmann S, Krüger J, Kegele J, Canafoglia L, Franceschetti S, Mayer T, Rebstock J, Zacher P, Ruf S, Alber M, Sterbova K, Lassuthová P, Vlckova M, Lemke JR, Platzer K, Krey I, Heine C, Wieczorek D, Kroell-Seger J, Lund C, Klein KM, Au PYB, Rho JM, Ho AW, Masnada S, Veggiotti P, Giordano L, Accorsi P, Hoei-Hansen CE, Striano P, Zara F, Verhelst H, Verhoeven JS, Braakman HMH, van der Zwaag B, Harder AVE, Brilstra E, Pendziwiat M, Lebon S, Vaccarezza M, Le NM, Christensen J, Grønborg S, Scherer SW, Howe J, Fazeli W, Howell KB, Leventer R, Stutterd C, Walsh S, Gerard M, Gerard B, Matricardi S, Bonardi CM, Sartori S, Berger A, Hoffman-Zacharska D, Mastrangelo M, Darra F, Vøllo A, Motazacker MM, Lakeman P, Nizon M, Betzler C, Altuzarra C, Caume R, Roubertie A, Gélisse P, Marini C, Guerrini R, Bilan F, Tibussek D, Koch-Hogrebe M, Perry MS, Ichikawa S, Dadali E, Sharkov A, Mishina I, Abramov M, Kanivets I, Korostelev S, Kutsev S, Wain KE, Eisenhauer N, Wagner M, Savatt JM, Müller-Schlüter K, Bassan H, Borovikov A, Nassogne MC, Destrée A, Schoonjans AS, Meuwissen M, Buzatu M, Jansen A, Scalais E, Srivastava S, Tan WH, Olson HE, Loddenkemper T, Poduri A, Helbig KL, Helbig I, Fitzgerald MP, Goldberg EM, Roser T, Borggraefe I, Brünger T, May P, Lal D, Lederer D, Rubboli G, Heyne HO, Lesca G, Hedrich UBS, Benda J, Gardella E, Lerche H, Møller RS. Genotype-phenotype correlations in SCN8A-related disorders reveal prognostic and therapeutic implications. Brain 2022; 145:2991-3009. [PMID: 34431999 PMCID: PMC10147326 DOI: 10.1093/brain/awab321] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 06/24/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
We report detailed functional analyses and genotype-phenotype correlations in 392 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel Nav1.6, with the aim of describing clinical phenotypes related to functional effects. Six different clinical subgroups were identified: Group 1, benign familial infantile epilepsy (n = 15, normal cognition, treatable seizures); Group 2, intermediate epilepsy (n = 33, mild intellectual disability, partially pharmaco-responsive); Group 3, developmental and epileptic encephalopathy (n = 177, severe intellectual disability, majority pharmaco-resistant); Group 4, generalized epilepsy (n = 20, mild to moderate intellectual disability, frequently with absence seizures); Group 5, unclassifiable epilepsy (n = 127); and Group 6, neurodevelopmental disorder without epilepsy (n = 20, mild to moderate intellectual disability). Those in Groups 1-3 presented with focal or multifocal seizures (median age of onset: 4 months) and focal epileptiform discharges, whereas the onset of seizures in patients with generalized epilepsy was later (median: 42 months) with generalized epileptiform discharges. We performed functional studies expressing missense variants in ND7/23 neuroblastoma cells and primary neuronal cultures using recombinant tetrodotoxin-insensitive human Nav1.6 channels and whole-cell patch-clamping. Two variants causing developmental and epileptic encephalopathy showed a strong gain-of-function (hyperpolarizing shift of steady-state activation, strongly increased neuronal firing rate) and one variant causing benign familial infantile epilepsy or intermediate epilepsy showed a mild gain-of-function (defective fast inactivation, less increased firing). In contrast, all three variants causing generalized epilepsy induced a loss-of-function (reduced current amplitudes, depolarizing shift of steady-state activation, reduced neuronal firing). Functional effects were known for 170 individuals. All 136 individuals carrying a functionally tested gain-of-function variant had either focal (n = 97, Groups 1-3) or unclassifiable (n = 39) epilepsy, whereas 34 individuals with a loss-of-function variant had either generalized (n = 14), no (n = 11) or unclassifiable (n = 6) epilepsy; only three had developmental and epileptic encephalopathy. Computational modelling in the gain-of-function group revealed a significant correlation between the severity of the electrophysiological and clinical phenotypes. Gain-of-function variant carriers responded significantly better to sodium channel blockers than to other anti-seizure medications, and the same applied for all individuals in Groups 1-3. In conclusion, our data reveal clear genotype-phenotype correlations between age at seizure onset, type of epilepsy and gain- or loss-of-function effects of SCN8A variants. Generalized epilepsy with absence seizures is the main epilepsy phenotype of loss-of-function variant carriers and the extent of the electrophysiological dysfunction of the gain-of-function variants is a main determinant of the severity of the clinical phenotype in focal epilepsies. Our pharmacological data indicate that sodium channel blockers present a treatment option in SCN8A-related focal epilepsy with onset in the first year of life.
Collapse
Affiliation(s)
- Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Center, 4293 Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, 5230 Odense, Denmark
| | - Yuanyuan Liu
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Mahmoud Koko
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Cathrine E Gjerulfsen
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Center, 4293 Dianalund, Denmark
| | - Lukas Sonnenberg
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
- Institute for Neurobiology, University of Tuebingen, 72072 Tuebingen, Germany
| | - Julian Schubert
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Christina D Fenger
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Center, 4293 Dianalund, Denmark
| | - Ahmed Eltokhi
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Maert Rannap
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Nils A Koch
- Institute for Neurobiology, University of Tuebingen, 72072 Tuebingen, Germany
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
- Institute for Neurobiology, University of Tuebingen, 72072 Tuebingen, Germany
| | - Johanna Krüger
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Josua Kegele
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Laura Canafoglia
- Department of Diagnostics and Technology, Fondazione IRCCS Istituto Neurologio Carlo Besta, 20125 Milan, Italy
| | - Silvana Franceschetti
- Department of Diagnostics and Technology, Fondazione IRCCS Istituto Neurologio Carlo Besta, 20125 Milan, Italy
| | - Thomas Mayer
- Epilepsy Center Kleinwachau, 01454 Dresden-Radeberg, Germany
| | | | - Pia Zacher
- Epilepsy Center Kleinwachau, 01454 Dresden-Radeberg, Germany
| | - Susanne Ruf
- Department of Pediatric Neurology and Developmental Medicine, University Children’s Hospital, 72072 Tuebingen, Germany
| | - Michael Alber
- Department of Pediatric Neurology and Developmental Medicine, University Children’s Hospital, 72072 Tuebingen, Germany
| | - Katalin Sterbova
- Department of Child Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 10000 Prague, Czech Republic
| | - Petra Lassuthová
- Department of Child Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 10000 Prague, Czech Republic
| | - Marketa Vlckova
- Department of Child Neurology, 2nd Faculty of Medicine, Charles University and University Hospital Motol, 10000 Prague, Czech Republic
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, 4275 Leipzig, Germany
| | - Konrad Platzer
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, 4275 Leipzig, Germany
| | - Ilona Krey
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, 4275 Leipzig, Germany
| | - Constanze Heine
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, 4275 Leipzig, Germany
| | - Dagmar Wieczorek
- Institute of Human Genetics, University Clinic, Heinrich-Heine-University, 40210 Düsseldorf, Germany
| | - Judith Kroell-Seger
- Children’s Department, Swiss Epilepsy Centre, Clinic Lengg, 8001 Zurich, Switzerland
| | - Caroline Lund
- National Centre for Rare Epilepsy-Related Disorders, Oslo University Hospital, 0001 Oslo, Norway
| | - Karl Martin Klein
- Departments of Clinical Neurosciences, Medical Genetics and Community Health Sciences, Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, Cumming School of Medicine, University of Calgary, Calgary, AB T2P 0A1, Canada
| | - P Y Billie Au
- Department of Medical Genetics, Alberta Children’s Hospital Research Institute, University of Calgary, AB T6G 2T4, Canada
| | - Jong M Rho
- Section of Pediatric Neurology, Alberta Children’s Hospital, Cumming School of Medicine, University of Calgary, Calgary, AB T2P 0A1, Canada
| | - Alice W Ho
- Section of Pediatric Neurology, Alberta Children’s Hospital, Cumming School of Medicine, University of Calgary, Calgary, AB T2P 0A1, Canada
| | - Silvia Masnada
- Department of Child Neurology, V. Buzzi Children’s Hospital, 20125 Milan, Italy
| | - Pierangelo Veggiotti
- Department of Child Neurology, V. Buzzi Children’s Hospital, 20125 Milan, Italy
- ‘L. Sacco’ Department of Biomedical and Clinical Sciences, University of Milan, 20157 Milan, Italy
| | - Lucio Giordano
- Child Neuropsychiatric Unit, Civilian Hospital, 25100 Brescia, Italy
| | - Patrizia Accorsi
- Child Neuropsychiatric Unit, Civilian Hospital, 25100 Brescia, Italy
| | - Christina E Hoei-Hansen
- Department of Pediatrics, Copenhagen University Hospital Rigshospitalet, 2200 Copenhagen, Denmark
- Department of Clinical Medicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, 16121 Genova, Italy
- IRCCS ‘G. Gaslini’ Institute, 16121 Genoa, Italy
| | | | - Helene Verhelst
- Department of Pediatrics, Division of Pediatric Neurology, Gent University Hospital, 9042 Gent, Belgium
| | - Judith S Verhoeven
- Academic Center for Epileptology, Kempenhaeghe/Maastricht University Medical Center, 5591 Heeze, The Netherlands
| | - Hilde M H Braakman
- Department of Pediatric Neurology, Amalia Children’s Hospital, Radboud University Medical Center, 6525 Nijmegen, The Netherlands
| | - Bert van der Zwaag
- Department of Genetics, University Medical Center Utrecht, Utrecht University, 3553 Utrecht, The Netherlands
| | - Aster V E Harder
- Department of Genetics, University Medical Center Utrecht, Utrecht University, 3553 Utrecht, The Netherlands
| | - Eva Brilstra
- Department of Genetics, University Medical Center Utrecht, Utrecht University, 3553 Utrecht, The Netherlands
| | - Manuela Pendziwiat
- Department of Neuropediatrics, Universitätsklinikum Schleswig Holstein Campus Kiel, 24106 Kiel, Germany
| | - Sebastian Lebon
- Pediatric Neurology and Neurorehabilitation Unit, Woman Mother Child Department, Lausanne University Hospital (CHUV), 1000 Lausanne, Switzerland
- University of Lausanne, 1000 Lausanne, Switzerland
| | - Maria Vaccarezza
- Department of Pediatric Neurology, Hospital Italiano de Buenos Aires, C1428 Buenos Aires, Argentina
| | - Ngoc Minh Le
- Center for Pediatric Neurology, Cleveland Clinic, Cleveland, OH 44102, USA
| | - Jakob Christensen
- Department of Neurology, Aarhus University Hospital, 8000 Aarhus, Denmark
| | - Sabine Grønborg
- Center for Rare Diseases, Department of Pediatrics and Department of Clinical Genetics, Copenhagen University Hospital Rigshospitalet, 2200 Copenhagen, Denmark
| | - Stephen W Scherer
- McLaughlin Centre and Department of Molecular Genetics, University of Toronto, Toronto, ON 66777, Canada
- The Centre for Applied Genomics and Department of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON 66777, Canada
| | - Jennifer Howe
- Department of Neuropediatrics, University Hospital Bonn, 53229 Bonn, Germany
| | - Walid Fazeli
- Institute for Molecular and Behavioral Neuroscience, University of Cologne, 50667 Cologne, Germany
- Neurology Department, The Royal Children’s Hospital Melbourne, 3002 Melbourne, Australia
| | - Katherine B Howell
- Neurology Department, The Royal Children’s Hospital Melbourne, 3002 Melbourne, Australia
- Murdoch Children’s Research Institute, 3052 Parkville, Australia
- Department of Pediatrics, University of Melbourne, Royal Children’s Hospital, 3052 Parkville, Australia
| | - Richard Leventer
- Neurology Department, The Royal Children’s Hospital Melbourne, 3002 Melbourne, Australia
- Murdoch Children’s Research Institute, 3052 Parkville, Australia
- Department of Pediatrics, University of Melbourne, Royal Children’s Hospital, 3052 Parkville, Australia
| | - Chloe Stutterd
- Murdoch Children’s Research Institute, 3052 Parkville, Australia
- Department of Pediatrics, University of Melbourne, Royal Children’s Hospital, 3052 Parkville, Australia
| | - Sonja Walsh
- Department of Neuropediatrics, Children’s Hospital, University Hospital Carl Gustav Carus, Technical University, 1099 Dresden, Germany
| | - Marion Gerard
- Genetics Department, CHU Côte de Nacre, 14118 Caen, France
| | | | - Sara Matricardi
- Child Neurology and Psychiatry Unit, Children’s Hospital G. Salesi, 60121 Ancona, Italy
| | - Claudia M Bonardi
- Department of Woman’s and Child’s Health, Padova University Hospital, 35100 Padova, Italy
| | - Stefano Sartori
- Child Neurology and Clinical Neurophysiology Unit, Padova University Hospital, 35100 Padova, Italy
| | - Andrea Berger
- Department of Neuropediatrics, Klinikum Weiden, Kliniken Nordoberpfalz AG, 92637 Weiden, Germany
| | | | - Massimo Mastrangelo
- Pediatric Neurology Unit, Vittore Buzzi Hospital, ASST Fatebenefratelli Sacco, 20100 Milan, Italy
| | - Francesca Darra
- Department of Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, 37121 Verona, Italy
| | - Arve Vøllo
- Department of Pediatrics, Oestfold Hospital, 1712 Graalum, Norway
| | - M Mahdi Motazacker
- Laboratory of Genome Diagnostics, Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, 1019 Amsterdam, Netherlands
| | - Phillis Lakeman
- Department of Clinical Genetics, Amsterdam Reproduction and Development Research Institute, Amsterdam UMC, University of Amsterdam, 1019 Amsterdam, Netherlands
| | - Mathilde Nizon
- Service de Génétique Médicale, CHU Nantes, 44093 Nantes, France
| | - Cornelia Betzler
- Clinic for Neuropediatrics and Neurorehabilitation, Epilepsy Center for Children and Adolescents, Schön Klinik, 83569 Vogtareuth, Germany
- Research Institute ‘Rehabilitation, Transition, Palliation’, PMU Salzburg, 5020 Salzburg, Austria
| | - Cecilia Altuzarra
- Department of Pediatrics, St. Jacques Hospital, 25000 Besançon, France
| | - Roseline Caume
- Clinique de Génétique Guy Fontaine, CHU Lille, 59000, Lille, France
| | - Agathe Roubertie
- Département de Neuropédiatrie, INSERM, CHU Montpellier, 34000 Montpellier, France
| | - Philippe Gélisse
- Département de Neuropédiatrie, INSERM, CHU Montpellier, 34000 Montpellier, France
| | - Carla Marini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Meyer Children’s Hospital, University of Florence, 50131 Florence, Italy
| | | | - Frederic Bilan
- Service de Génétique, Centre Hospitalier Universitaire de Poitiers, 86021 Poitiers, France
| | - Daniel Tibussek
- Child Neurology, Center for Pediatric and Teenage Health Care, 53757 Sankt Augustin, Germany
| | | | - M Scott Perry
- Justin Neurosciences Center, Cook Children’s Medical Center, Fort Worth, TX 76101, USA
| | - Shoji Ichikawa
- Department of Clinical Diagnostics, Ambry Genetics, Aliso Viejo, CA 92637, USA
| | - Elena Dadali
- Research Centre for Medical Genetics, 115522 Moscow, Russia
- Veltischev Research and Clinical Institute for Pediatrics, Pirogov Russian National Research Medical University, 125412 Moscow, Russia
| | - Artem Sharkov
- Veltischev Research and Clinical Institute for Pediatrics, Pirogov Russian National Research Medical University, 125412 Moscow, Russia
- Genomed Ltd., 100000 Moscow, Russia
| | - Irina Mishina
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | - Mikhail Abramov
- Veltischev Research and Clinical Institute for Pediatrics, Pirogov Russian National Research Medical University, 125412 Moscow, Russia
| | - Ilya Kanivets
- Svt. Luka’s Institute of Child Neurology & Epilepsy, 100000 Moscow, Russia
- Russian Medical Academy of Continuous Professional Education, 100000 Moscow, Russia
| | - Sergey Korostelev
- Svt. Luka’s Institute of Child Neurology & Epilepsy, 100000 Moscow, Russia
- I.M. Sechenov First Moscow State Medical University, 100000 Moscow, Russia
| | - Sergey Kutsev
- Research Centre for Medical Genetics, 115522 Moscow, Russia
| | - Karen E Wain
- Geisinger Autism & Developmental Medicine Institute, Lewisburg, PA 17837, USA
| | - Nancy Eisenhauer
- Geisinger Autism & Developmental Medicine Institute, Lewisburg, PA 17837, USA
| | - Monisa Wagner
- Geisinger Autism & Developmental Medicine Institute, Lewisburg, PA 17837, USA
| | - Juliann M Savatt
- Geisinger Autism & Developmental Medicine Institute, Lewisburg, PA 17837, USA
| | - Karen Müller-Schlüter
- Epilepsy Center for Children, University Hospital Neuruppin, Brandenburg Medical School, 16816 Neuruppin, Germany
| | - Haim Bassan
- Pediatric Neurology & Development Center, Shamir Medical Center (Assaf Harofe), Be'er Ya'akov, Israel
- Sackler Faculty of Medicine, Tel Aviv University, 5296001 Tel Aviv, Israel
| | | | - Marie Cecile Nassogne
- Pediatric Neurology Unit, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, 1000 Brussels, Belgium
| | - Anne Destrée
- Institute for Pathology and Genetics, 6040 Gosselies, Belgium
| | - An Sofie Schoonjans
- Department of Pediatrics and Pediatric Neurology, Antwerp University Hospital, University of Antwerp, 2650 Edegem, Belgium
| | - Marije Meuwissen
- Pediatric Neurology, Marie Curie Hospital—CHU Charleroi, 6032 Charleroi, Belgium
| | - Marga Buzatu
- Pediatric Neurology, Marie Curie Hospital—CHU Charleroi, 6032 Charleroi, Belgium
| | - Anna Jansen
- Pediatric Neurology Unit, Department of Pediatrics, Universitair Ziekenhuis Brussel, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Emmanuel Scalais
- Pediatric Neurology Unit, Department of Pediatrics, Centre Hospitalier de Luxembourg, 1313 Luxembourg, Luxembourg
| | - Siddharth Srivastava
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02108, USA
| | - Wen Hann Tan
- Department of Genetics, Boston Children’s Hospital, Boston, MA 02108, USA
| | - Heather E Olson
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02108, USA
- Epilepsy Genetics Program, Boston Children’s Hospital, Boston, MA 02108, USA
| | - Tobias Loddenkemper
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02108, USA
| | - Annapurna Poduri
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02108, USA
- Epilepsy Genetics Program, Boston Children’s Hospital, Boston, MA 02108, USA
| | - Katherine L Helbig
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- The Epilepsy Neurogenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Ingo Helbig
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- The Epilepsy Neurogenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA 19104 USA
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104 USA
- Institute of Clinical Molecular Biology, Kiel University, 24105 Kiel, Germany
- Department of Neuropediatrics, Kiel University, 24105 Kiel, Germany
| | - Mark P Fitzgerald
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- The Epilepsy Neurogenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Biomedical and Health Informatics (DBHi), Children’s Hospital of Philadelphia, Philadelphia, PA 19104 USA
- Institute of Clinical Molecular Biology, Kiel University, 24105 Kiel, Germany
| | - Ethan M Goldberg
- Division of Neurology, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- The Epilepsy Neurogenetics Initiative (ENGIN), Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Timo Roser
- Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Department of Pediatrics, Dr. von Haunersches Children’s Hospital, Ludwig-Maximilian-University of Munich, 80331 Munich, Germany
| | - Ingo Borggraefe
- Division of Pediatric Neurology, Developmental Medicine and Social Pediatrics, Department of Pediatrics, Dr. von Haunersches Children’s Hospital, Ludwig-Maximilian-University of Munich, 80331 Munich, Germany
- Comprehensive Epilepsy Center, Ludwig-Maximilian- University of Munich, 80331 Munich, Germany
| | - Tobias Brünger
- Luxembourg Centre for Systems Biomedicine (LCSB), University Luxembourg, L-4243 Esch-sur-Alzette, Luxembourg
| | - Patrick May
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44102, USA
| | - Dennis Lal
- Luxembourg Centre for Systems Biomedicine (LCSB), University Luxembourg, L-4243 Esch-sur-Alzette, Luxembourg
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH 44102, USA
- Stanley Center for Psychiatric Research, Broad Institute of Harvard and M.I.T., Cambridge, MA 02138, USA
- Cologne Center for Genomics (CCG), University of Cologne, 50667 Cologne, Germany
| | - Damien Lederer
- Institute for Pathology and Genetics, 6040 Gosselies, Belgium
| | - Guido Rubboli
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Center, 4293 Dianalund, Denmark
- University of Copenhagen, 2200 Copenhagen, Denmark
| | - Henrike O Heyne
- Institute of Human Genetics, University of Leipzig Hospitals and Clinics, 4275 Leipzig, Germany
- Finnish Institute for Molecular Medicine (FIMM), University of Helsinki, 320 Helsinki, Finland
- Program for Medical and Population Genetics/Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02108, USA
| | - Gaetan Lesca
- Department of Medical Genetics, Groupement Hospitalier Est and ERN EpiCARE, University Hospitals of Lyon (HCL), 69001 Lyon, France
- Institut Neuromyogène, CNRS UMR 5310 - INSERM U1217, Université de Lyon, Université Claude Bernard Lyon 1, 69001 Lyon, France
| | - Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Jan Benda
- Institute for Neurobiology, University of Tuebingen, 72072 Tuebingen, Germany
| | - Elena Gardella
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Center, 4293 Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, 5230 Odense, Denmark
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72072 Tuebingen, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Center, 4293 Dianalund, Denmark
- Institute for Regional Health Services, University of Southern Denmark, 5230 Odense, Denmark
| |
Collapse
|
5
|
Functional correlates of clinical phenotype and severity in recurrent SCN2A variants. Commun Biol 2022; 5:515. [PMID: 35637276 PMCID: PMC9151917 DOI: 10.1038/s42003-022-03454-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/05/2022] [Indexed: 01/24/2023] Open
Abstract
In SCN2A-related disorders, there is an urgent demand to establish efficient methods for determining the gain- (GoF) or loss-of-function (LoF) character of variants, to identify suitable candidates for precision therapies. Here we classify clinical phenotypes of 179 individuals with 38 recurrent SCN2A variants as early-infantile or later-onset epilepsy, or intellectual disability/autism spectrum disorder (ID/ASD) and assess the functional impact of 13 variants using dynamic action potential clamp (DAPC) and voltage clamp. Results show that 36/38 variants are associated with only one phenotypic group (30 early-infantile, 5 later-onset, 1 ID/ASD). Unexpectedly, we revealed major differences in outcome severity between individuals with the same variant for 40% of early-infantile variants studied. DAPC was superior to voltage clamp in predicting the impact of mutations on neuronal excitability and confirmed GoF produces early-infantile phenotypes and LoF later-onset phenotypes. For one early-infantile variant, the co-expression of the α1 and β2 subunits of the Nav1.2 channel was needed to unveil functional impact, confirming the prediction of 3D molecular modeling. Neither DAPC nor voltage clamp reliably predicted phenotypic severity of early-infantile variants. Genotype, phenotypic group and DAPC are accurate predictors of the biophysical impact of SCN2A variants, but other approaches are needed to predict severity. A comprehensive biophysical analysis of disease-associated mutations in the voltage-gated sodium channel gene, SCN2A, suggests that dynamic action potential clamp may be a better predictor than voltage clamp of how these mutations alter neuronal excitability, though other approaches are needed to predict severity.
Collapse
|
6
|
Richardson R, Baralle D, Bennett C, Briggs T, Bijlsma EK, Clayton-Smith J, Constantinou P, Foulds N, Jarvis J, Jewell R, Johnson DS, McEntagart M, Parker MJ, Radley JA, Robertson L, Ruivenkamp C, Rutten JW, Tellez J, Turnpenny PD, Wilson V, Wright M, Balasubramanian M. Further delineation of phenotypic spectrum of SCN2A-related disorder. Am J Med Genet A 2022; 188:867-877. [PMID: 34894057 DOI: 10.1002/ajmg.a.62595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 09/28/2021] [Accepted: 11/20/2021] [Indexed: 01/12/2023]
Abstract
SCN2A-related disorders include intellectual disability, autism spectrum disorder, seizures, episodic ataxia, and schizophrenia. In this study, the phenotype-genotype association in SCN2A-related disorders was further delineated by collecting detailed clinical and molecular characteristics. Using previously proposed genotype-phenotype hypotheses based on variant function and position, the potential of phenotype prediction from the variants found was examined. Patients were identified through the Deciphering Developmental Disorders study and gene matching strategies. Phenotypic information and variant interpretation evidence were collated. Seventeen previously unreported patients and five patients who had been previously reported (but with minimal phenotypic and segregation data) were included (10 males, 12 females; median age 10.5 years). All patients had developmental delays and the majority had intellectual disabilities. Seizures were reported in 15 of 22 (68.2%), four of 22 (18.2%) had autism spectrum disorder and no patients were reported with episodic ataxia. The majority of variants were de novo. One family had presumed gonadal mosaicism. The correlation of the use of sodium channel-blocking antiepileptic drugs with phenotype or genotype was variable. These data suggest that variant type and position alone can provide some predictive information about the phenotype in a proportion of cases, but more precise assessment of variant function is needed for meaningful phenotype prediction.
Collapse
Affiliation(s)
- Ruth Richardson
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Diana Baralle
- University Hospital of Southampton NHS Foundation Trust, Southampton, UK
- Faculty of Medicine, University of Southampton, Southampton, UK
| | - Christopher Bennett
- Yorkshire Regional Genetics Service, The Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Tracy Briggs
- NW Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Emilia K Bijlsma
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jill Clayton-Smith
- NW Genomic Laboratory Hub, Manchester Centre for Genomic Medicine, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | | | - Nicola Foulds
- University Hospital of Southampton NHS Foundation Trust, Southampton, UK
| | - Joanna Jarvis
- Clinical Genetics Unit, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, UK
| | - Rosalyn Jewell
- Yorkshire Regional Genetics Service, The Leeds Teaching Hospitals NHS Trust, Leeds, UK
| | - Diana S Johnson
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Meriel McEntagart
- South West Thames Regional Genetics Centre, St. George's Healthcare NHS Trust, St. George's, University of London, London, UK
| | - Michael J Parker
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Jessica A Radley
- London North West Regional Genetics Service, St. Mark's and Northwick Park Hospitals, London, UK
| | | | - Claudia Ruivenkamp
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Julie W Rutten
- Department of Clinical Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - James Tellez
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Peter D Turnpenny
- Clinical Genetics Department, Royal Devon and Exeter NHS Foundation Trust, Exeter, UK
| | - Valerie Wilson
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Michael Wright
- Northern Genetics Service, Newcastle Upon Tyne Hospitals NHS Trust, Newcastle, UK
| | - Meena Balasubramanian
- Sheffield Clinical Genetics Service, Sheffield Children's NHS Foundation Trust, Sheffield, UK
- Academic Unit of Child Health, Department of Oncology and Metabolism, University of Sheffield, Sheffield, UK
| |
Collapse
|
7
|
Zeng Q, Yang Y, Duan J, Niu X, Chen Y, Wang D, Zhang J, Chen J, Yang X, Li J, Yang Z, Jiang Y, Liao J, Zhang Y. SCN2A-Related Epilepsy: The Phenotypic Spectrum, Treatment and Prognosis. Front Mol Neurosci 2022; 15:809951. [PMID: 35431799 PMCID: PMC9005871 DOI: 10.3389/fnmol.2022.809951] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 02/14/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE The aim of this study was to analyze the phenotypic spectrum, treatment, and prognosis of 72 Chinese children with SCN2A variants. METHODS The SCN2A variants were detected by next-generation sequencing. All patients were followed up at a pediatric neurology clinic in our hospital or by telephone. RESULTS In 72 patients with SCN2A variants, the seizure onset age ranged from the first day of life to 2 years and 6 months. The epilepsy phenotypes included febrile seizures (plus) (n = 2), benign (familial) infantile epilepsy (n = 9), benign familial neonatal-infantile epilepsy (n = 3), benign neonatal epilepsy (n = 1), West syndrome (n = 16), Ohtahara syndrome (n = 15), epilepsy of infancy with migrating focal seizures (n = 2), Dravet syndrome (n = 1), early infantile epileptic encephalopathy (n = 15), and unclassifiable developmental and epileptic encephalopathy (n = 8). Approximately 79.2% (57/72) patients had varying degrees of developmental delay. All patients had abnormal MRI findings with developmental delay. 91.7% (55/60) patients with de novo SCN2A variants had development delay, while only 16.7% (2/12) patients with inherited SCN2A variants had abnormal development. 83.9% (26/31) SCN2A variants that were located in transmembrane regions of the protein were detected in patients with development delay. Approximately 69.2% (9/13) SCN2A variants detected in patients with normal development were located in the non-transmembrane regions. Approximately 54.2% (39/72) patients were seizure-free at a median age of 8 months. Oxcarbazepine has been used by 38 patients, and seizure-free was observed in 11 of them (11/38, 28.9%), while 6 patients had seizure worsening by oxcarbazepine. All 3 patients used oxcarbazepine and with seizure onset age > 1 year presented seizure exacerbation after taking oxcarbazepine. Valproate has been used by 53 patients, seizure-free was observed in 22.6% (12/53) of them. CONCLUSION The phenotypic spectrum of SCN2A-related epilepsy was broad, ranging from benign epilepsy in neonate and infancy to severe epileptic encephalopathy. Oxcarbazepine and valproate were the most effective drugs in epilepsy patients with SCN2A variants. Sodium channel blockers often worsen seizures in patients with seizure onset beyond 1 year of age. Abnormal brain MRI findings and de novo variations were often related to poor prognosis. Most SCN2A variants located in transmembrane regions were related to patients with developmental delay.
Collapse
Affiliation(s)
- Qi Zeng
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Ying Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jing Duan
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Xueyang Niu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yi Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Dan Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jing Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiaoyang Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaoling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jinliang Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
- *Correspondence: Jianxiang Liao,
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Yuehua Zhang,
| |
Collapse
|
8
|
Liu Y, Koko M, Lerche H. A SCN8A variant associated with severe early onset epilepsy and developmental delay: Loss- or gain-of-function? Epilepsy Res 2021; 178:106824. [PMID: 34847423 DOI: 10.1016/j.eplepsyres.2021.106824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 10/19/2022]
Abstract
SCN8A, encoding the voltage-gated sodium channel subunit NaV1.6, has been associated with a wide spectrum of neuropsychiatric disorders. Missense variants in SCN8A which increase the channel activity can cause a severe developmental and epileptic encephalopathy (DEE). One DEE variant (p.(Arg223Gly)) was described to cause a predominant loss-of-function (LOF) mechanism when expressed in neuroblastoma cells, which is not consistent with the genotype-phenotype correlations in this gene. To resolve this discrepancy and understand the pathophysiological mechanism of this variant, we performed comprehensive electrophysiological studies in both neuroblastoma cells and primary hippocampal neuronal cultures. Although we also found that p.(Arg223Gly) significantly decreased Na+ current density and enhanced fast inactivation compared to the wild type (WT) channel in transfected neuroblastoma cells (both LOF mechanisms), it also caused a strong hyperpolarizing shift of steady-state activation and accelerated the recovery from fast inactivation (both gain-of-function (GOF) mechanisms). In cultured neurons transfected with mutant vs. WT NaV1.6 channels, we found more depolarized resting membrane potentials and a decreased rheobase leading to enhanced action potential firing. We conclude that SCN8A p.(Arg223Gly) leads to a net GOF resulting in neuronal hyperexcitability and a higher firing rate, fitting with the central role of GOF mechanisms in DEE.
Collapse
Affiliation(s)
- Yuanyuan Liu
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Mahmoud Koko
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
| |
Collapse
|
9
|
Gorman KM, Peters CH, Lynch B, Jones L, Bassett DS, King MD, Ruben PC, Rosch RE. Persistent sodium currents in SCN1A developmental and degenerative epileptic dyskinetic encephalopathy. Brain Commun 2021; 3:fcab235. [PMID: 34755109 PMCID: PMC8568850 DOI: 10.1093/braincomms/fcab235] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 06/15/2021] [Accepted: 06/21/2021] [Indexed: 11/14/2022] Open
Abstract
Pathogenic variants in the voltage-gated sodium channel gene (SCN1A) are amongst the most common genetic causes of childhood epilepsies. There is considerable heterogeneity in both the types of causative variants and associated phenotypes; a recent expansion of the phenotypic spectrum of SCN1A associated epilepsies now includes an early onset severe developmental and epileptic encephalopathy with regression and a hyperkinetic movement disorder. Herein, we report a female with a developmental and degenerative epileptic-dyskinetic encephalopathy, distinct and more severe than classic Dravet syndrome. Clinical diagnostics indicated a paternally inherited c.5053G>T; p. A1685S variant of uncertain significance in SCN1A. Whole-exome sequencing detected a second de novo mosaic (18%) c.2345G>A; p. T782I likely pathogenic variant in SCN1A (maternal allele). Biophysical characterization of both mutant channels in a heterologous expression system identified gain-of-function effects in both, with a milder shift in fast inactivation of the p. A1685S channels; and a more severe persistent sodium current in the p. T782I. Using computational models, we show that large persistent sodium currents induce hyper-excitability in individual cortical neurons, thus relating the severe phenotype to the empirically quantified sodium channel dysfunction. These findings further broaden the phenotypic spectrum of SCN1A associated epilepsies and highlight the importance of testing for mosaicism in epileptic encephalopathies. Detailed biophysical evaluation and computational modelling further highlight the role of gain-of-function variants in the pathophysiology of the most severe phenotypes associated with SCN1A.
Collapse
Affiliation(s)
- Kathleen M Gorman
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Colin H Peters
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.,Department of Physiology and Biophysics, University of Colorado, Denver, CO, USA
| | - Bryan Lynch
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland
| | - Laura Jones
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Dani S Bassett
- Departments of Bioengineering, Electrical & Systems Engineering, Physics & Astronomy, Neurology, and Psychiatry, University of Pennsylvania, Philadelphia, PA, USA.,Santa Fe Institute, Santa Fe, NM, USA
| | - Mary D King
- Department of Neurology and Clinical Neurophysiology, Children's Health Ireland at Temple Street, Dublin, Ireland.,School of Medicine and Medical Science, University College Dublin, Dublin, Ireland
| | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
| | - Richard E Rosch
- Department of Paediatric Neurology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.,Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.,MRC Centre for Neurodevelopmental Disorders, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK
| |
Collapse
|
10
|
Guerrini R, Balestrini S, Wirrell EC, Walker MC. Monogenic Epilepsies: Disease Mechanisms, Clinical Phenotypes, and Targeted Therapies. Neurology 2021; 97:817-831. [PMID: 34493617 PMCID: PMC10336826 DOI: 10.1212/wnl.0000000000012744] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 08/18/2021] [Indexed: 02/05/2023] Open
Abstract
A monogenic etiology can be identified in up to 40% of people with severe epilepsy. To address earlier and more appropriate treatment strategies, clinicians are required to know the implications that specific genetic causes might have on pathophysiology, natural history, comorbidities, and treatment choices. In this narrative review, we summarize concepts on the genetic epilepsies based on the underlying pathophysiologic mechanisms and present the current knowledge on treatment options based on evidence provided by controlled trials or studies with lower classification of evidence. Overall, evidence robust enough to guide antiseizure medication (ASM) choices in genetic epilepsies remains limited to the more frequent conditions for which controlled trials and observational studies have been possible. Most monogenic disorders are very rare and ASM choices for them are still based on inferences drawn from observational studies and early, often anecdotal, experiences with precision therapies. Precision medicine remains applicable to only a narrow number of patients with monogenic epilepsies and may target only part of the actual functional defects. Phenotypic heterogeneity is remarkable, and some genetic mutations activate epileptogenesis through their developmental effects, which may not be reversed postnatally. Other genes seem to have pure functional consequences on excitability, acting through either loss- or gain-of-function effects, and these may have opposite treatment implications. In addition, the functional consequences of missense mutations may be difficult to predict, making precision treatment approaches considerably more complex than estimated by deterministic interpretations. Knowledge of genetic etiologies can influence the approach to surgical treatment of focal epilepsies. Identification of germline mutations in specific genes contraindicates surgery while mutations in other genes do not. Identification, quantification, and functional characterization of specific somatic mutations before surgery using CSF liquid biopsy or after surgery in brain specimens will likely be integrated in planning surgical strategies and reintervention after a first unsuccessful surgery as initial evidence suggests that mutational load may correlate with the epileptogenic zone. Promising future directions include gene manipulation by DNA or mRNA targeting; although most are still far from clinical use, some are in early phase clinical development.
Collapse
Affiliation(s)
- Renzo Guerrini
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN.
| | - Simona Balestrini
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN
| | - Elaine C Wirrell
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN
| | - Matthew C Walker
- From the Neuroscience Department (R.G., S.B.), Meyer Children's Hospital-University of Florence, Italy; Department of Clinical and Experimental Epilepsy (S.B., M.C.W.), UCL Queen Square Institute of Neurology, London; Chalfont Centre for Epilepsy (S.B.), Buckinghamshire, UK; and Divisions of Child and Adolescent Neurology and Epilepsy (E.C.W.), Department of Neurology, Mayo Clinic, Rochester, MN
| |
Collapse
|
11
|
Palmer EE, Howell K, Scheffer IE. Natural History Studies and Clinical Trial Readiness for Genetic Developmental and Epileptic Encephalopathies. Neurotherapeutics 2021; 18:1432-1444. [PMID: 34708325 PMCID: PMC8608984 DOI: 10.1007/s13311-021-01133-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/27/2021] [Indexed: 02/04/2023] Open
Abstract
The developmental and epileptic encephalopathies (DEEs) are the most severe group of epilepsies. They usually begin in infancy or childhood with drug-resistant seizures, epileptiform EEG patterns, developmental slowing or regression, and cognitive impairment. DEEs have a high mortality and profound morbidity; comorbidities are common including autism spectrum disorders. With advances in genetic sequencing, over 400 genes have been implicated in DEEs, with a genetic cause now identified in over 50% patients. Each genetic DEE typically has a broad genotypic-phenotypic spectrum, based on the underlying pathophysiology. There is a pressing need to improve health outcomes by developing novel targeted therapies for specific genetic DEE phenotypes that not only improve seizure control, but also developmental outcomes and comorbidities. Clinical trial readiness relies firstly on a deep understanding of phenotype-genotype correlation and evolution of a condition over time, in order to select appropriate patients for clinical trials. Understanding the natural history of the disorder informs assessment of treatment efficacy in terms of both clinical outcome and biomarker utility. Natural history studies (NHS) provide a high quality, integrated, comprehensive approach to understanding a complex disease and underpin clinical trial design for novel therapies. NHS are pre-planned observational studies designed to track the course of a disease and identify demographic, genetic, environmental, and other variables, including biomarkers, that correlate with the disease's evolution and outcomes. Due to the rarity of individual genetic DEEs, appropriately funded high-quality DEE NHS will be required, with sustainable frameworks and equitable access to affected individuals globally.
Collapse
Affiliation(s)
- Elizabeth E Palmer
- School of Women's and Children's Health, UNSW, Sydney, NSW, Australia
- Sydney Children's Hospital Network, Sydney, NSW, Australia
| | - Katherine Howell
- Department of Neurology, Royal Children's Hospital, Parkville, VIC, Australia
- Murdoch Children's Research Institute, Melbourne, VIC, Australia
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia
- Florey Institute for Neuroscience and Mental Health, Melbourne, VIC, Australia
| | - Ingrid E Scheffer
- Department of Neurology, Royal Children's Hospital, Parkville, VIC, Australia.
- Murdoch Children's Research Institute, Melbourne, VIC, Australia.
- Department of Paediatrics, University of Melbourne, Melbourne, VIC, Australia.
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, VIC, Australia.
- Florey Institute for Neuroscience and Mental Health, Melbourne, VIC, Australia.
| |
Collapse
|
12
|
Scala M, Efthymiou S, Sultan T, De Waele J, Panciroli M, Salpietro V, Maroofian R, Striano P, Van Petegem F, Houlden H, Bosmans F. Homozygous SCN1B variants causing early infantile epileptic encephalopathy 52 affect voltage-gated sodium channel function. Epilepsia 2021; 62:e82-e87. [PMID: 33901312 PMCID: PMC8585727 DOI: 10.1111/epi.16913] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 04/08/2021] [Accepted: 04/08/2021] [Indexed: 10/21/2022]
Abstract
We identified nine patients from four unrelated families harboring three biallelic variants in SCN1B (NM_001037.5: c.136C>T; p.[Arg46Cys], c.178C>T; p.[Arg60Cys], and c.472G>A; p.[Val158Met]). All subjects presented with early infantile epileptic encephalopathy 52 (EIEE52), a rare, severe developmental and epileptic encephalopathy featuring infantile onset refractory seizures followed by developmental stagnation or regression. Because SCN1B influences neuronal excitability through modulation of voltage-gated sodium (NaV ) channel function, we examined the effects of human SCN1BR46C (β1R46C ), SCN1BR60C (β1R60C ), and SCN1BV158M (β1V158M ) on the three predominant brain NaV channel subtypes NaV 1.1 (SCN1A), NaV 1.2 (SCN2A), and NaV 1.6 (SCN8A). We observed a shift toward more depolarizing potentials of conductance-voltage relationships (NaV 1.2/β1R46C , NaV 1.2/β1R60C , NaV 1.6/β1R46C , NaV 1.6/β1R60C , and NaV 1.6/β1V158M ) and channel availability (NaV 1.1/β1R46C , NaV 1.1/β1V158M , NaV 1.2/β1R46C , NaV 1.2/β1R60C , and NaV 1.6/β1V158M ), and detected a slower recovery from fast inactivation for NaV 1.1/β1V158M . Combined with modeling data indicating perturbation-induced structural changes in β1, these results suggest that the SCN1B variants reported here can disrupt normal NaV channel function in the brain, which may contribute to EIEE52.
Collapse
Affiliation(s)
- Marcello Scala
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Stephanie Efthymiou
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Tipu Sultan
- Department of Pediatric Neurology, Children's Hospital and Institute of Child Health Lahore, Lahore, Pakistan
| | - Jolien De Waele
- Faculty of Medicine and Health Sciences, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| | - Marta Panciroli
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Vincenzo Salpietro
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Reza Maroofian
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, and Maternal and Child Health, University of Genoa, Genoa, Italy
- Pediatric Neurology and Muscular Diseases Unit, G. Gaslini Institute, Genoa, Italy
| | - Filip Van Petegem
- Department of Biochemistry and Molecular Biology, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Henry Houlden
- Department of Neuromuscular Disorders, Institute of Neurology, University College London, London, UK
| | - Frank Bosmans
- Faculty of Medicine and Health Sciences, Department of Basic and Applied Medical Sciences, Ghent University, Ghent, Belgium
| |
Collapse
|
13
|
Mantegazza M, Cestèle S, Catterall WA. Sodium channelopathies of skeletal muscle and brain. Physiol Rev 2021; 101:1633-1689. [PMID: 33769100 DOI: 10.1152/physrev.00025.2020] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Voltage-gated sodium channels initiate action potentials in nerve, skeletal muscle, and other electrically excitable cells. Mutations in them cause a wide range of diseases. These channelopathy mutations affect every aspect of sodium channel function, including voltage sensing, voltage-dependent activation, ion conductance, fast and slow inactivation, and both biosynthesis and assembly. Mutations that cause different forms of periodic paralysis in skeletal muscle were discovered first and have provided a template for understanding structure, function, and pathophysiology at the molecular level. More recent work has revealed multiple sodium channelopathies in the brain. Here we review the well-characterized genetics and pathophysiology of the periodic paralyses of skeletal muscle and then use this information as a foundation for advancing our understanding of mutations in the structurally homologous α-subunits of brain sodium channels that cause epilepsy, migraine, autism, and related comorbidities. We include studies based on molecular and structural biology, cell biology and physiology, pharmacology, and mouse genetics. Our review reveals unexpected connections among these different types of sodium channelopathies.
Collapse
Affiliation(s)
- Massimo Mantegazza
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France.,INSERM, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- Université Cote d'Azur, Valbonne-Sophia Antipolis, France.,CNRS UMR7275, Institut de Pharmacologie Moléculaire et Cellulaire, Valbonne-Sophia Antipolis, France
| | | |
Collapse
|
14
|
Crawford K, Xian J, Helbig KL, Galer PD, Parthasarathy S, Lewis-Smith D, Kaufman MC, Fitch E, Ganesan S, O'Brien M, Codoni V, Ellis CA, Conway LJ, Taylor D, Krause R, Helbig I. Computational analysis of 10,860 phenotypic annotations in individuals with SCN2A-related disorders. Genet Med 2021; 23:1263-1272. [PMID: 33731876 PMCID: PMC8257493 DOI: 10.1038/s41436-021-01120-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 02/04/2021] [Accepted: 02/05/2021] [Indexed: 11/10/2022] Open
Abstract
Purpose Pathogenic variants in SCN2A cause a wide range of neurodevelopmental phenotypes. Reports of genotype–phenotype correlations are often anecdotal, and the available phenotypic data have not been systematically analyzed. Methods We extracted phenotypic information from primary descriptions of SCN2A-related disorders in the literature between 2001 and 2019, which we coded in Human Phenotype Ontology (HPO) terms. With higher-level phenotype terms inferred by the HPO structure, we assessed the frequencies of clinical features and investigated the association of these features with variant classes and locations within the NaV1.2 protein. Results We identified 413 unrelated individuals and derived a total of 10,860 HPO terms with 562 unique terms. Protein-truncating variants were associated with autism and behavioral abnormalities. Missense variants were associated with neonatal onset, epileptic spasms, and seizures, regardless of type. Phenotypic similarity was identified in 8/62 recurrent SCN2A variants. Three independent principal components accounted for 33% of the phenotypic variance, allowing for separation of gain-of-function versus loss-of-function variants with good performance. Conclusion Our work shows that translating clinical features into a computable format using a standardized language allows for quantitative phenotype analysis, mapping the phenotypic landscape of SCN2A-related disorders in unprecedented detail and revealing genotype–phenotype correlations along a multidimensional spectrum.
Collapse
Affiliation(s)
- Katherine Crawford
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Genetic Counseling, Arcadia University, Glenside, PA, USA
| | - Julie Xian
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Neuroscience Program, University of Pennsylvania, Philadelphia, PA, USA
| | - Katherine L Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Peter D Galer
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Shridhar Parthasarathy
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biology, The College of New Jersey, Ewing Township, NJ, USA
| | - David Lewis-Smith
- Translational and Clinical Research Institute, Newcastle University, Newcastle-upon-Tyne, UK.,Royal Victoria Infirmary, Newcastle-upon-Tyne, UK
| | - Michael C Kaufman
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Eryn Fitch
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Shiva Ganesan
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Margaret O'Brien
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Veronica Codoni
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg
| | - Colin A Ellis
- The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA
| | - Laura J Conway
- Genetic Counseling, Arcadia University, Glenside, PA, USA
| | - Deanne Taylor
- Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pediatrics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Roland Krause
- Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Belvaux, Luxembourg
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA. .,The Epilepsy NeuroGenetics Initiative (ENGIN), Children's Hospital of Philadelphia, Philadelphia, PA, USA. .,Department of Biomedical and Health Informatics (DBHi), Children's Hospital of Philadelphia, Philadelphia, PA, USA. .,Department of Neurology, University of Pennsylvania, Philadelphia, PA, USA.
| |
Collapse
|
15
|
Abstract
Voltage-gated sodium channels (VGSCs) are foundational to excitable cell function: Their coordinated passage of sodium ions into the cell is critical for the generation and propagation of action potentials throughout the nervous system. The classical paradigm of action potential physiology states that sodium passes through the membrane only transiently (1-2 milliseconds), before the channels inactivate and cease to conduct sodium ions. However, in reality, a small fraction of the total sodium current (1%-2%) remains at steady state despite prolonged depolarization. While this persistent sodium current (INaP) contributes to normal physiological functioning of neurons, accumulating evidence indicates a particularly pathogenic role for an elevated INaP in epilepsy (reviewed previously1). Due to significant advances over the past decade of epilepsy research concerning the importance of INaP in sodium channelopathies, this review seeks to summarize recent evidence and highlight promising novel anti-seizure medication strategies through preferentially targeting INaP.
Collapse
Affiliation(s)
- Eric R. Wengert
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA
| | - Manoj K. Patel
- Department of Anesthesiology, University of Virginia Health System, Charlottesville, VA, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA
| |
Collapse
|
16
|
Impact of predictive, preventive and precision medicine strategies in epilepsy. Nat Rev Neurol 2020; 16:674-688. [PMID: 33077944 DOI: 10.1038/s41582-020-0409-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2020] [Indexed: 12/15/2022]
Abstract
Over the last decade, advances in genetics, neuroimaging and EEG have enabled the aetiology of epilepsy to be identified earlier in the disease course than ever before. At the same time, progress in the study of experimental models of epilepsy has provided a better understanding of the mechanisms underlying the condition and has enabled the identification of therapies that target specific aetiologies. We are now witnessing the impact of these advances in our daily clinical practice. Thus, now is the time for a paradigm shift in epilepsy treatment from a reactive attitude, treating patients after the onset of epilepsy and the initiation of seizures, to a proactive attitude that is more broadly integrated into a 'P4 medicine' approach. This P4 approach, which is personalized, predictive, preventive and participatory, puts patients at the centre of their own care and, ultimately, aims to prevent the onset of epilepsy. This aim will be achieved by adapting epilepsy treatments not only to a given syndrome but also to a given patient and moving from the usual anti-seizure treatments to personalized treatments designed to target specific aetiologies. In this Review, we present the current state of this ongoing revolution, emphasizing the impact on clinical practice.
Collapse
|
17
|
Heyne HO, Baez-Nieto D, Iqbal S, Palmer DS, Brunklaus A, May P, Johannesen KM, Lauxmann S, Lemke JR, Møller RS, Pérez-Palma E, Scholl UI, Syrbe S, Lerche H, Lal D, Campbell AJ, Wang HR, Pan J, Daly MJ. Predicting functional effects of missense variants in voltage-gated sodium and calcium channels. Sci Transl Med 2020; 12:eaay6848. [PMID: 32801145 DOI: 10.1126/scitranslmed.aay6848] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 11/20/2019] [Accepted: 07/22/2020] [Indexed: 12/30/2022]
Abstract
Malfunctions of voltage-gated sodium and calcium channels (encoded by SCNxA and CACNA1x family genes, respectively) have been associated with severe neurologic, psychiatric, cardiac, and other diseases. Altered channel activity is frequently grouped into gain or loss of ion channel function (GOF or LOF, respectively) that often corresponds not only to clinical disease manifestations but also to differences in drug response. Experimental studies of channel function are therefore important, but laborious and usually focus only on a few variants at a time. On the basis of known gene-disease mechanisms of 19 different diseases, we inferred LOF (n = 518) and GOF (n = 309) likely pathogenic variants from the disease phenotypes of variant carriers. By training a machine learning model on sequence- and structure-based features, we predicted LOF or GOF effects [area under the receiver operating characteristics curve (ROC) = 0.85] of likely pathogenic missense variants. Our LOF versus GOF prediction corresponded to molecular LOF versus GOF effects for 87 functionally tested variants in SCN1/2/8A and CACNA1I (ROC = 0.73) and was validated in exome-wide data from 21,703 cases and 128,957 controls. We showed respective regional clustering of inferred LOF and GOF nucleotide variants across the alignment of the entire gene family, suggesting shared pathomechanisms in the SCNxA/CACNA1x family genes.
Collapse
Affiliation(s)
- Henrike O Heyne
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
| | - David Baez-Nieto
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Sumaiya Iqbal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Duncan S Palmer
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Sick Children, Glasgow G51 4TF, UK
- School of Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Patrick May
- Luxembourg Centre for Systems Biomedicine, Belvaux, University of Luxembourg, 4365 Esch-sur-Alzette, Luxembourg
| | - Katrine M Johannesen
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, 04103 Leipzig, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Centre, 4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Eduardo Pérez-Palma
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
| | - Ute I Scholl
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Department of Nephrology and Medical Intensive Care and BIH Center for Regenerative Therapies, 10178 Berlin, Germany
- Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Steffen Syrbe
- Division of Pediatric Epileptology, Center for Paediatrics and Adolescent Medicine, University Hospital Heidelberg, 69120 Heidelberg, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, 72076 Tuebingen, Germany
| | - Dennis Lal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Cologne Center for Genomics (CCG), University of Cologne, 50923, Germany
- Genomic Medicine Institute, Lemer Research Institute Cleveland Clinic, OH G92J47, USA
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH G92J47, USA
| | - Arthur J Campbell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Center for Development of Therapeutics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Hao-Ran Wang
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Jen Pan
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Mark J Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, 5WR36M Helsinki, Finland
| |
Collapse
|
18
|
Brunklaus A, Lal D. Sodium channel epilepsies and neurodevelopmental disorders: from disease mechanisms to clinical application. Dev Med Child Neurol 2020; 62:784-792. [PMID: 32227486 DOI: 10.1111/dmcn.14519] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/04/2020] [Indexed: 12/18/2022]
Abstract
Genetic variants in brain-expressed voltage-gated sodium channels (SCNs) have emerged as one of the most frequent causes of Mendelian forms of epilepsy and neurodevelopmental disorders (NDDs). This review explores the biological concepts that underlie sodium channel NDDs, explains their phenotypic heterogeneity, and appraises how this knowledge may inform clinical practice. We observe that excitatory/inhibitory neuronal expression ratios of sodium channels are important regulatory mechanisms underlying brain development, homeostasis, and neurological diseases. We hypothesize that a detailed understanding of gene expression, variant tolerance, location, and function, as well as timing of seizure onset can aid the understanding of how variants in SCN1A, SCN2A, SCN3A, and SCN8A contribute to seizure aetiology and inform treatment choice. We propose a model in which variant type, development-specific gene expression, and functions of SCNs explain the heterogeneity of sodium channel associated NDDs. Understanding of basic disease mechanisms and detailed knowledge of variant characteristics have increasing influence on clinical decision making, enabling us to stratify treatment and move closer towards precision medicine in sodium channel epilepsy and NDDs. WHAT THIS PAPER ADDS: Sodium-channel disorder heterogeneity is explained by variant-specific gene expression timing and function. Gene tolerance and location analyses aid sodium channel variant interpretation. Sodium-channel variant characteristics can contribute to clinical decision making.
Collapse
Affiliation(s)
- Andreas Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Dennis Lal
- Cologne Center for Genomics, University Hospital Cologne, University of Cologne, Cologne, Germany.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, USA.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, USA.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA.,Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH, USA
| |
Collapse
|
19
|
Miao P, Tang S, Ye J, Wang J, Lou Y, Zhang B, Xu X, Chen X, Li Y, Feng J. Electrophysiological features: The next precise step for SCN2A developmental epileptic encephalopathy. Mol Genet Genomic Med 2020; 8:e1250. [PMID: 32400968 PMCID: PMC7336724 DOI: 10.1002/mgg3.1250] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2019] [Revised: 03/01/2020] [Accepted: 03/05/2020] [Indexed: 12/19/2022] Open
Abstract
Background To investigate the relationships among phenotypes, genotypes, and funotypes of SCN2A‐related developmental epileptic encephalopathy (DEE). Methods We enrolled five DEE patients with five de novo variants of the SCN2A. Functional analysis and pharmacological features of Nav1.2 channel protein expressed in HEK293T cells were characterized by whole‐cell patch‐clamp recording. Results The phenotypes of c.4712T>C(p. I1571T), c.2995G>A(p.E999K), and c.4015A>G(p. N1339D) variants showed similar characteristics, including early seizure onset with severe to profound intellectual disability. Electrophysiological recordings revealed a hyperpolarizing shift in the voltage dependence of the activation curve and smaller recovery time constants of fast‐inactivation than in wild type, indicating a prominent gain of function (GOF). Moreover, pharmacological electrophysiology showed that phenytoin inhibited over a 70% peak current and was more effective than oxcarbazepine and carbamazepine. In contrast, c.4972C>T (p.P1658S) and c.5317G>A (p.A1773T) led to loss of function (LOF) changes, showing reduced current density and enhanced fast inactivation. Both showed seizure onset after 3 months of age with moderate development delay. Interestingly, we discovered that choreoathetosis was a specific phenotype feature. Conclusion These findings provided the insights into the phenotype–genotype–funotype relationships of SCN2A‐related DEE. The preliminary evaluation using the distinct hints of GOF and LOF helped plan the treatment, and the next precise step should be electrophysiological study.
Collapse
Affiliation(s)
- Pu Miao
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Siyang Tang
- Children's Hospital and Department of Biophysics, National Clinical Research Center for Child Health, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jia Ye
- Children's Hospital and Department of Biophysics, National Clinical Research Center for Child Health, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianda Wang
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuting Lou
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Bijun Zhang
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoxiao Xu
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Xiaoquan Chen
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yuezhou Li
- Children's Hospital and Department of Biophysics, National Clinical Research Center for Child Health, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Jianhua Feng
- Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| |
Collapse
|
20
|
Hedrich UBS, Lauxmann S, Lerche H. SCN2A channelopathies: Mechanisms and models. Epilepsia 2020; 60 Suppl 3:S68-S76. [PMID: 31904120 DOI: 10.1111/epi.14731] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 03/21/2019] [Indexed: 01/01/2023]
Abstract
Variants in the SCN2A gene, encoding the voltage-gated sodium channel NaV 1.2, cause a variety of neuropsychiatric syndromes with different severity ranging from self-limiting epilepsies with early onset to developmental and epileptic encephalopathy with early or late onset and intellectual disability (ID), as well as ID or autism without seizures. Functional analysis of channel defects demonstrated a genotype-phenotype correlation and suggested effective treatment options for one group of affected patients carrying gain-of-function variants. Here, we sum up the functional mechanisms underlying different phenotypes of patients with SCN2A channelopathies and present currently available models that can help in understanding SCN2A-related disorders.
Collapse
Affiliation(s)
- Ulrike B S Hedrich
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Stephan Lauxmann
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| |
Collapse
|
21
|
Wolff M, Brunklaus A, Zuberi SM. Phenotypic spectrum and genetics of SCN2A-related disorders, treatment options, and outcomes in epilepsy and beyond. Epilepsia 2020; 60 Suppl 3:S59-S67. [PMID: 31904126 DOI: 10.1111/epi.14935] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 12/25/2022]
Abstract
Pathogenic variants in the SCN2A gene are associated with a variety of neurodevelopmental phenotypes, defined in recent years through multicenter collaboration. Phenotypes include benign (self-limited) neonatal and infantile epilepsy and more severe developmental and epileptic encephalopathies also presenting in early infancy. There is increasing evidence that an important phenotype linked to the gene is autism and intellectual disability without epilepsy or with rare seizures in later childhood. Other associations of SCN2A include the movement disorders chorea and episodic ataxia. It is likely that as genetic testing enters mainstream practice that new phenotypic associations will be identified. Some missense, gain of function variants tend to present in early infancy with epilepsy, whereas other missense or truncating, loss of function variants present with later-onset epilepsies or intellectual disability only. Knowledge of both mutation type and functional consequences can guide precision therapy. Sodium channel blockers may be effective antiepileptic medications in gain of function, neonatal and infantile presentations.
Collapse
Affiliation(s)
- Markus Wolff
- Pediatric Neurology, Vivantes Hospital Neukoelln, Berlin, Germany
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Children & School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children & School of Medicine, University of Glasgow, Glasgow, UK
| |
Collapse
|
22
|
Brunklaus A, Du J, Steckler F, Ghanty II, Johannesen KM, Fenger CD, Schorge S, Baez-Nieto D, Wang HR, Allen A, Pan JQ, Lerche H, Heyne H, Symonds JD, Zuberi SM, Sanders S, Sheidley BR, Craiu D, Olson HE, Weckhuysen S, DeJonge P, Helbig I, Van Esch H, Busa T, Milh M, Isidor B, Depienne C, Poduri A, Campbell AJ, Dimidschstein J, Møller RS, Lal D. Biological concepts in human sodium channel epilepsies and their relevance in clinical practice. Epilepsia 2020; 61:387-399. [PMID: 32090326 DOI: 10.1111/epi.16438] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 01/06/2020] [Accepted: 01/06/2020] [Indexed: 01/07/2023]
Abstract
OBJECTIVE Voltage-gated sodium channels (SCNs) share similar amino acid sequence, structure, and function. Genetic variants in the four human brain-expressed SCN genes SCN1A/2A/3A/8A have been associated with heterogeneous epilepsy phenotypes and neurodevelopmental disorders. To better understand the biology of seizure susceptibility in SCN-related epilepsies, our aim was to determine similarities and differences between sodium channel disorders, allowing us to develop a broader perspective on precision treatment than on an individual gene level alone. METHODS We analyzed genotype-phenotype correlations in large SCN-patient cohorts and applied variant constraint analysis to identify severe sodium channel disease. We examined temporal patterns of human SCN expression and correlated functional data from in vitro studies with clinical phenotypes across different sodium channel disorders. RESULTS Comparing 865 epilepsy patients (504 SCN1A, 140 SCN2A, 171 SCN8A, four SCN3A, 46 copy number variation [CNV] cases) and analysis of 114 functional studies allowed us to identify common patterns of presentation. All four epilepsy-associated SCN genes demonstrated significant constraint in both protein truncating and missense variation when compared to other SCN genes. We observed that age at seizure onset is related to SCN gene expression over time. Individuals with gain-of-function SCN2A/3A/8A missense variants or CNV duplications share similar characteristics, most frequently present with early onset epilepsy (<3 months), and demonstrate good response to sodium channel blockers (SCBs). Direct comparison of corresponding SCN variants across different SCN subtypes illustrates that the functional effects of variants in corresponding channel locations are similar; however, their clinical manifestation differs, depending on their role in different types of neurons in which they are expressed. SIGNIFICANCE Variant function and location within one channel can serve as a surrogate for variant effects across related sodium channels. Taking a broader view on precision treatment suggests that in those patients with a suspected underlying genetic epilepsy presenting with neonatal or early onset seizures (<3 months), SCBs should be considered.
Collapse
Affiliation(s)
- Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Juanjiangmeng Du
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany
| | - Felix Steckler
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Ismael I Ghanty
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Katrine M Johannesen
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Christina Dühring Fenger
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Amplexa Genetics, Odense, Denmark
| | - Stephanie Schorge
- Department of Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK.,School of Pharmacy, University College London, London, UK
| | - David Baez-Nieto
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Hao-Ran Wang
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Andrew Allen
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Jen Q Pan
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, Germany
| | - Henrike Heyne
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts.,Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Joseph D Symonds
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, UK.,School of Medicine, University of Glasgow, Glasgow, UK
| | - Stephan Sanders
- Department of Psychiatry, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California
| | - Beth R Sheidley
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Dana Craiu
- Carol Davila University of Medicine, Department of Clinical Neurosciences, Pediatric Neurology Discipline, Bucharest, Romania.,Alexandru Obregia Hospital, Pediatric Neurology Clinic, Bucharest, Romania
| | - Heather E Olson
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts
| | - Sarah Weckhuysen
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Peter DeJonge
- Neurogenetics Group, Center for Molecular Neurology, VIB, Antwerp, Belgium.,Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, Antwerp, Belgium.,Department of Neurology, University Hospital Antwerp, Antwerp, Belgium
| | - Ingo Helbig
- Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Epilepsy NeuroGenetics Initiative, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Biomedical and Health Informatics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.,Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.,Department of Neuropediatrics, University of Kiel, Kiel, Germany
| | - Hilde Van Esch
- Department of Human Genetics and Center for Human Genetics, Laboratory for Genetics of Cognition, University Hospitals Leuven, Leuven, Belgium
| | - Tiffany Busa
- Genetics Department, Timone Enfants University Hospital Center, Public Assistance-Marseille Hospitals, Marseille, France
| | - Matthieu Milh
- Medical Genetics and Functional Genomics, National Institute of Health and Medical Research, Mixed Unit of Research S910, Aix-Marseille University, Marseille, France.,Hematology Laboratory, Le Mans Hospital Center, Le Mans, France
| | - Bertrand Isidor
- Medical Genetics Department, Nantes University Hospital Center, Nantes, France
| | - Christel Depienne
- Institute of Human Genetics, Essen University Hospital, Essen, Germany.,Brain and Spinal Cord Institute, National Institute of Health and Medical Research, Unit 1127, National Center for Scientific Research, Mixed Unit of Research 7225, Sorbonne Universities, Pierre and Marie Curie University, Mixed Unit of Research S 1127, Brain & Spine Institute, Paris, France
| | - Annapurna Poduri
- Epilepsy Genetics Program, Division of Epilepsy and Clinical Neurophysiology, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts.,Harvard Medical School, Boston, Massachusetts
| | | | - Jordane Dimidschstein
- Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts
| | - Rikke S Møller
- Deparment of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Center Filadelfia, Dianalund, Denmark.,Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Dennis Lal
- Cologne Center for Genomics, University of Cologne, University Hospital Cologne, Cologne, Germany.,Stanley Center for Psychiatric Research, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, Massachusetts.,Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, Ohio.,Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| |
Collapse
|
23
|
Hedrich UBS, Koch H, Becker A, Lerche H. [Epileptogenesis and consequences for treatment]. DER NERVENARZT 2019; 90:773-780. [PMID: 31243507 DOI: 10.1007/s00115-019-0749-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Epilepsy is a frequent and disabling neurological disease with a significant burden for patients and their relatives worldwide. Epileptogenesis is understood as the plastic process that after an insult (in acquired epilepsies) finally leads to seizures with a latent period. In some cases, epileptogenesis has been clarified down to the molecular level. In parallel, the discovery of genetic defects has decisively contributed to unravel epileptic disease mechanisms. Both research directions have enabled first personalized treatment options. In addition, genetic variants associated with epilepsy can not only directly cause seizures but likely also induce an epileptogenic process (similar as in acquired epilepsies) and interact with developmental processes of the brain, finally leading to the typical age-dependent manifestation of genetic epilepsy syndromes. This article describes these correlations and the consequences for personalized treatment possibilities.
Collapse
Affiliation(s)
- Ulrike B S Hedrich
- Abteilung Neurologie mit Schwerpunkt Epileptologie, Hertie-Institut für klinische Hirnforschung, Universität Tübingen, Hoppe Seyler Straße 3, 72076, Tübingen, Deutschland
| | - Henner Koch
- Abteilung Neurologie mit Schwerpunkt Epileptologie, Hertie-Institut für klinische Hirnforschung, Universität Tübingen, Hoppe Seyler Straße 3, 72076, Tübingen, Deutschland
| | - Albert Becker
- Institut für Neuropathologie, Universitätsklinikum Bonn, Bonn, Deutschland
| | - Holger Lerche
- Abteilung Neurologie mit Schwerpunkt Epileptologie, Hertie-Institut für klinische Hirnforschung, Universität Tübingen, Hoppe Seyler Straße 3, 72076, Tübingen, Deutschland.
| |
Collapse
|
24
|
Begemann A, Acuña MA, Zweier M, Vincent M, Steindl K, Bachmann-Gagescu R, Hackenberg A, Abela L, Plecko B, Kroell-Seger J, Baumer A, Yamakawa K, Inoue Y, Asadollahi R, Sticht H, Zeilhofer HU, Rauch A. Further corroboration of distinct functional features in SCN2A variants causing intellectual disability or epileptic phenotypes. Mol Med 2019; 25:6. [PMID: 30813884 PMCID: PMC6391808 DOI: 10.1186/s10020-019-0073-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/05/2019] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Deleterious variants in the voltage-gated sodium channel type 2 (Nav1.2) lead to a broad spectrum of phenotypes ranging from benign familial neonatal-infantile epilepsy (BFNIE), severe developmental and epileptic encephalopathy (DEE) and intellectual disability (ID) to autism spectrum disorders (ASD). Yet, the underlying mechanisms are still incompletely understood. METHODS To further elucidate the genotype-phenotype correlation of SCN2A variants we investigated the functional effects of six variants representing the phenotypic spectrum by whole-cell patch-clamp studies in transfected HEK293T cells and in-silico structural modeling. RESULTS The two variants p.L1342P and p.E1803G detected in patients with early onset epileptic encephalopathy (EE) showed profound and complex changes in channel gating, whereas the BFNIE variant p.L1563V exhibited only a small gain of channel function. The three variants identified in ID patients without seizures, p.R937C, p.L611Vfs*35 and p.W1716*, did not produce measurable currents. Homology modeling of the missense variants predicted structural impairments consistent with the electrophysiological findings. CONCLUSIONS Our findings support the hypothesis that complete loss-of-function variants lead to ID without seizures, small gain-of-function variants cause BFNIE and EE variants exhibit variable but profound Nav1.2 gating changes. Moreover, structural modeling was able to predict the severity of the variant impact, supporting a potential role of structural modeling as a prognostic tool. Our study on the functional consequences of SCN2A variants causing the distinct phenotypes of EE, BFNIE and ID contributes to the elucidation of mechanisms underlying the broad phenotypic variability reported for SCN2A variants.
Collapse
Affiliation(s)
- Anaïs Begemann
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | - Mario A Acuña
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zurich, Switzerland
| | - Markus Zweier
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | - Marie Vincent
- Service de génétique médicale, CHU Nantes, 44093, Nantes, France
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | | | - Annette Hackenberg
- Division of Child Neurology, University Children's Hospital Zurich, 8032, Zurich, Switzerland
| | - Lucia Abela
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Division of Child Neurology, University Children's Hospital Zurich, 8032, Zurich, Switzerland
| | - Barbara Plecko
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Division of Child Neurology, University Children's Hospital Zurich, 8032, Zurich, Switzerland.,Division of General Pediatrics, Department of Pediatrics and Adolescent Medicine, Medical University of Graz, 8036, Graz, Austria
| | - Judith Kroell-Seger
- Children's department, Swiss Epilepsy Centre, Clinic Lengg, 8008, Zurich, Switzerland
| | - Alessandra Baumer
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako-shi, Saitama, 351-0198, Japan
| | - Yushi Inoue
- National Epilepsy Center, NHO Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan
| | - Reza Asadollahi
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland.,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland
| | - Heinrich Sticht
- Institute of Biochemistry, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054, Erlangen, Germany
| | - Hanns Ulrich Zeilhofer
- radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland.,Institute of Pharmacology and Toxicology, University of Zurich, 8057, Zurich, Switzerland.,Institute of Pharmaceutical Sciences, ETH Zurich, 8093, Zürich, Switzerland.,Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland
| | - Anita Rauch
- Institute of Medical Genetics, University of Zurich, 8952, Schlieren, Zurich, Switzerland. .,radiz-Rare Disease Initiative Zürich, Clinical Research Priority Program for Rare Diseases, University of Zurich, 8006, Zurich, Switzerland. .,Neuroscience Center Zurich, University of Zurich and ETH Zurich, 8057, Zurich, Switzerland. .,Zurich Center for Integrative Human Physiology, University of Zurich, 8057, Zurich, Switzerland.
| |
Collapse
|