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Dong R, Jin R, Zhang H, Zhang H, Xue M, Li Y, Zhang K, Lv Y, Li X, Liu Y, Gai Z. Genotypic and phenotypic characteristics of sodium channel-associated epilepsy in Chinese population. J Hum Genet 2024:10.1038/s10038-024-01257-2. [PMID: 38880818 DOI: 10.1038/s10038-024-01257-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 04/27/2024] [Accepted: 04/30/2024] [Indexed: 06/18/2024]
Abstract
Variants in voltage-gated sodium channel (VGSC) genes are implicated in seizures, epilepsy, and neurodevelopmental disorders, constituting a significant aspect of hereditary epilepsy in the Chinese population. Through retrospective analysis utilizing next-generation sequencing (NGS), we examined the genotypes and phenotypes of VGSC-related epilepsy cases from a cohort of 691 epilepsy subjects. Our findings revealed that 5.1% of subjects harbored VGSC variants, specifically 22 with SCN1A, 9 with SCN2A, 1 with SCN8A, and 3 with SCN1B variants; no SCN3A variants were detected. Among these, 14 variants were previously reported, while 21 were newly identified. SCN1A variant carriers predominantly presented with Dravet Syndrome (DS) and Genetic Epilepsy with Febrile Seizures Plus (GEFS + ), featuring a heightened sensitivity to fever-induced seizures. Statistically significant disparities emerged between the SCN1A-DS and SCN1A-GEFS+ groups concerning seizure onset and genetic diagnosis age, incidence of status epilepticus, mental retardation, anti-seizure medication (ASM) responsiveness, and familial history. Notably, subjects with SCN1A variants affecting the protein's pore region experienced more frequent cluster seizures. All SCN2A variants were of de novo origin, and 88.9% of individuals with SCN2A variations exhibited cluster seizures. This research reveals a significant association between variations in VGSC-related genes and the clinical phenotype diversity of epilepsy subjects in China, emphasizing the pivotal role of NGS screening in establishing accurate disease diagnoses and guiding the selection of ASM.
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Affiliation(s)
- Rui Dong
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Ruifeng Jin
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
- Department of neurology, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
| | - Hongwei Zhang
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
- Department of neurology, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
| | - Haiyan Zhang
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Min Xue
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Yue Li
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Kaihui Zhang
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Yuqiang Lv
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
| | - Xiaoying Li
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China.
- Neonatology department, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China.
| | - Yi Liu
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China.
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China.
| | - Zhongtao Gai
- Pediatric Research Institute, Children's Hospital Affiliated to Shandong University (Jinan Children's Hospital), Jinan, China
- Shandong Provincial Clinical Research Center for Children's Health and Disease, Jinan, China
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Chowdhury SR, Whitney R, RamachandranNair R, Bijarnia Mahay S, Sharma S. Genetic Testing in Pediatric Epilepsy: Tools, Tips, and Navigating the Traps. Pediatr Neurol 2024; 157:42-49. [PMID: 38865949 DOI: 10.1016/j.pediatrneurol.2024.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/17/2024] [Accepted: 05/13/2024] [Indexed: 06/14/2024]
Abstract
With the advent of high-throughput sequencing and computational methods, genetic testing has become an integral part of contemporary clinical practice, particularly in epilepsy. The toolbox for genetic testing has evolved from conventional chromosomal microarray and epilepsy gene panels to state-of-the-art sequencing techniques in the modern genomic era. Beyond its potential for therapeutic benefits through precision medicine, optimizing the choice of antiseizure medications, or exploring nonpharmacological therapeutic modalities, genetic testing carries substantial diagnostic, prognostic, and personal implications. Developmental and epileptic encephalopathies, the coexistence of neurodevelopmental comorbidities, early age of epilepsy onset, unexplained drug-refractory epilepsy, and positive family history have demonstrated the highest likelihood of yielding positive genetic test results. Given the diagnostic efficacy across different testing modalities, reducing costs of next-generation sequencing tests, and genetic diversity of epilepsies, exome sequencing or genome sequencing, where feasible and available, have been recommended as the first-tier test. Comprehensive clinical phenotyping at the outset, corroborative evidence from radiology and electrophysiology-based investigations, reverse phenotyping, and periodic reanalysis are some of the valuable strategies when faced with inconclusive test results. In this narrative review, the authors aim to simplify the approach to genetic testing in epilepsy by guiding on the selection of appropriate testing tools in the indicated clinical scenarios, addressing crucial aspects during pre- and post-test counseling sessions, adeptly navigating the traps posed by uncertain or negative genetic variants, and paving the way forward to the emerging testing modalities beyond DNA sequencing.
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Affiliation(s)
- Sayoni Roy Chowdhury
- Department of Paediatrics, Lady Hardinge Medical College and Associated Kalawati Saran Children's Hospital, New Delhi, India
| | - Robyn Whitney
- Comprehensive Paediatric Epilepsy Program, Division of Neurology, Department of Pediatrics, McMaster Children's Hospital, Hamilton, Ontario, Canada
| | - Rajesh RamachandranNair
- Comprehensive Paediatric Epilepsy Program, Division of Neurology, Department of Pediatrics, McMaster Children's Hospital, Hamilton, Ontario, Canada
| | - Sunita Bijarnia Mahay
- Sr. Consultant, Clinical & Metabolic Geneticist, Institute of Medical Genetics & Genomics, Sir Ganga Ram Hospital, New Delhi, India
| | - Suvasini Sharma
- Department of Paediatrics, Lady Hardinge Medical College and Associated Kalawati Saran Children's Hospital, New Delhi, India.
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Qu G, Merchant JP, Clatot J, DeFlitch LM, Frederick DJ, Tang S, Salvatore M, Zhang X, Li J, Anderson SA, Goldberg EM. Targeted blockade of aberrant sodium current in a stem cell-derived neuron model of SCN3A encephalopathy. Brain 2024; 147:1247-1263. [PMID: 37935051 PMCID: PMC10994535 DOI: 10.1093/brain/awad376] [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: 06/28/2023] [Revised: 09/30/2023] [Accepted: 10/20/2023] [Indexed: 11/09/2023] Open
Abstract
Missense variants in SCN3A encoding the voltage-gated sodium (Na+) channel α subunit Nav1.3 are associated with SCN3A-related neurodevelopmental disorder (SCN3A-NDD), a spectrum of disease that includes epilepsy and malformation of cortical development. How genetic variation in SCN3A leads to pathology remains unclear, as prior electrophysiological work on disease-associated variants has been performed exclusively in heterologous cell systems. To further investigate the mechanisms of SCN3A-NDD pathogenesis, we used CRISPR/Cas9 gene editing to modify a control human induced pluripotent stem cell (iPSC) line to express the recurrent de novo missense variant SCN3A c.2624T>C (p.Ile875Thr). With the established Ngn2 rapid induction protocol, we generated glutamatergic forebrain-like neurons (iNeurons), which we showed to express SCN3A mRNA and Nav1.3-mediated Na+ currents. We performed detailed whole-cell patch clamp recordings to determine the effect of the SCN3A-p.Ile875Thr variant on endogenous Na+ currents in, and intrinsic excitability of, human neurons. Compared to control iNeurons, variant-expressing iNeurons exhibit markedly increased slowly-inactivating/persistent Na+ current, abnormal firing patterns with paroxysmal bursting and plateau-like potentials with action potential failure, and a hyperpolarized voltage threshold for action potential generation. We then validated these findings using a separate iPSC line generated from a patient harbouring the SCN3A-p.Ile875Thr variant compared to a corresponding CRISPR-corrected isogenic control line. Finally, we found that application of the Nav1.3-selective blocker ICA-121431 normalizes action potential threshold and aberrant firing patterns in SCN3A-p.Ile1875Thr iNeurons; in contrast, consistent with action as a Na+ channel blocker, ICA-121431 decreases excitability of control iNeurons. Our findings demonstrate that iNeurons can model the effects of genetic variation in SCN3A yet reveal a complex relationship between gain-of-function at the level of the ion channel versus impact on neuronal excitability. Given the transient expression of SCN3A in the developing human nervous system, selective blockade or suppression of Nav1.3-containing Na+ channels could represent a therapeutic approach towards SCN3A-NDD.
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Affiliation(s)
- Guojie Qu
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Julie P Merchant
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Jérôme Clatot
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Leah M DeFlitch
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Danny J Frederick
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Sheng Tang
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Madeleine Salvatore
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Xiaohong Zhang
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Jianping Li
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
| | - Stewart A Anderson
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Child and Adolescent Psychiatry, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Psychiatry, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
| | - Ethan M Goldberg
- Division of Neurology, Department of Pediatrics, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Neuroscience, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
- The Epilepsy NeuroGenetics Initiative, The Children’s Hospital of Philadelphia, Philadelphia, PA, 19104, USA
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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Lin Y, Tao E, Champion JP, Corry B. A binding site for phosphoinositides described by multiscale simulations explains their modulation of voltage-gated sodium channels. eLife 2024; 12:RP91218. [PMID: 38465747 DOI: 10.7554/elife.91218] [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] [Indexed: 03/12/2024] Open
Abstract
Voltage-gated sodium channels (Naᵥ) are membrane proteins which open to facilitate the inward flux of sodium ions into excitable cells. In response to stimuli, Naᵥ channels transition from the resting, closed state to an open, conductive state, before rapidly inactivating. Dysregulation of this functional cycle due to mutations causes diseases including epilepsy, pain conditions, and cardiac disorders, making Naᵥ channels a significant pharmacological target. Phosphoinositides are important lipid cofactors for ion channel function. The phosphoinositide PI(4,5)P2 decreases Naᵥ1.4 activity by increasing the difficulty of channel opening, accelerating fast inactivation and slowing recovery from fast inactivation. Using multiscale molecular dynamics simulations, we show that PI(4,5)P2 binds stably to inactivated Naᵥ at a conserved site within the DIV S4-S5 linker, which couples the voltage-sensing domain (VSD) to the pore. As the Naᵥ C-terminal domain is proposed to also bind here during recovery from inactivation, we hypothesize that PI(4,5)P2 prolongs inactivation by competitively binding to this site. In atomistic simulations, PI(4,5)P2 reduces the mobility of both the DIV S4-S5 linker and the DIII-IV linker, responsible for fast inactivation, slowing the conformational changes required for the channel to recover to the resting state. We further show that in a resting state Naᵥ model, phosphoinositides bind to VSD gating charges, which may anchor them and impede VSD activation. Our results provide a mechanism by which phosphoinositides alter the voltage dependence of activation and the rate of recovery from inactivation, an important step for the development of novel therapies to treat Naᵥ-related diseases.
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Affiliation(s)
- Yiechang Lin
- Research School of Biology, Australian National University, Canberra, Australia
| | - Elaine Tao
- Research School of Biology, Australian National University, Canberra, Australia
| | - James P Champion
- Research School of Biology, Australian National University, Canberra, Australia
| | - Ben Corry
- Research School of Biology, Australian National University, Canberra, Australia
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Rusina E, Simonti M, Duprat F, Cestèle S, Mantegazza M. Voltage-gated sodium channels in genetic epilepsy: up and down of excitability. J Neurochem 2023. [PMID: 37654020 DOI: 10.1111/jnc.15947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/11/2023] [Accepted: 08/13/2023] [Indexed: 09/02/2023]
Abstract
The past two decades have witnessed a wide range of studies investigating genetic variants of voltage-gated sodium (NaV ) channels, which are involved in a broad spectrum of diseases, including several types of epilepsy. We have reviewed here phenotypes and pathological mechanisms of genetic epilepsies caused by variants in NaV α and β subunits, as well as of some relevant interacting proteins (FGF12/FHF1, PRRT2, and Ankyrin-G). Notably, variants of all these genes can induce either gain- or loss-of-function of NaV leading to either neuronal hyperexcitability or hypoexcitability. We present the results of functional studies obtained with different experimental models, highlighting that they should be interpreted considering the features of the experimental system used. These systems are models, but they have allowed us to better understand pathophysiological issues, ameliorate diagnostics, orientate genetic counseling, and select/develop therapies within a precision medicine framework. These studies have also allowed us to gain insights into the physiological roles of different NaV channels and of the cells that express them. Overall, our review shows the progress that has been made, but also the need for further studies on aspects that have not yet been clarified. Finally, we conclude by highlighting some significant themes of general interest that can be gleaned from the results of the work of the last two decades.
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Affiliation(s)
- Evgeniia Rusina
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Martina Simonti
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Fabrice Duprat
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
- Inserm, Valbonne-Sophia Antipolis, France
| | - Sandrine Cestèle
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
| | - Massimo Mantegazza
- University Cote d'Azur, Valbonne-Sophia Antipolis, France
- CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), Valbonne-Sophia Antipolis, France
- Inserm, Valbonne-Sophia Antipolis, France
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Zidar N, Tomašič T, Kikelj D, Durcik M, Tytgat J, Peigneur S, Rogers M, Haworth A, Kirby RW. New aryl and acylsulfonamides as state-dependent inhibitors of Na v1.3 voltage-gated sodium channel. Eur J Med Chem 2023; 258:115530. [PMID: 37329714 DOI: 10.1016/j.ejmech.2023.115530] [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: 09/26/2022] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 06/19/2023]
Abstract
Voltage-gated sodium channels (Navs) play an essential role in neurotransmission, and their dysfunction is often a cause of various neurological disorders. The Nav1.3 isoform is found in the CNS and upregulated after injury in the periphery, but its role in human physiology has not yet been fully elucidated. Reports suggest that selective Nav1.3 inhibitors could be used as novel therapeutics to treat pain or neurodevelopmental disorders. Few selective inhibitors of this channel are known in the literature. In this work, we report the discovery of a new series of aryl and acylsulfonamides as state-dependent inhibitors of Nav1.3 channels. Using a ligand-based 3D similarity search and subsequent hit optimization, we identified and prepared a series of 47 novel compounds and tested them on Nav1.3, Nav1.5, and a selected subset also on Nav1.7 channels in a QPatch patch-clamp electrophysiology assay. Eight compounds had an IC50 value of less than 1 μM against the Nav1.3 channel inactivated state, with one compound displaying an IC50 value of 20 nM, whereas activity against the inactivated state of the Nav1.5 channel and Nav1.7 channel was approximately 20-fold weaker. None of the compounds showed use-dependent inhibition of the cardiac isoform Nav1.5 at a concentration of 30 μM. Further selectivity testing of the most promising hits was measured using the two-electrode voltage-clamp method against the closed state of the Nav1.1-Nav1.8 channels, and compound 15b displayed small, yet selective, effects against the Nav1.3 channel, with no activity against the other isoforms. Additional selectivity testing of promising hits against the inactivated state of the Nav1.3, Nav1.7, and Nav1.8 channels revealed several compounds with robust and selective activity against the inactivated state of the Nav1.3 channel among the three isoforms tested. Moreover, the compounds were not cytotoxic at a concentration of 50 μM, as demonstrated by the assay in human HepG2 cells (hepatocellular carcinoma cells). The novel state-dependent inhibitors of Nav1.3 discovered in this work provide a valuable tool to better evaluate this channel as a potential drug target.
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Affiliation(s)
- Nace Zidar
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia.
| | - Tihomir Tomašič
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia
| | - Danijel Kikelj
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia
| | - Martina Durcik
- University of Ljubljana, Faculty of Pharmacy, Aškerčeva cesta 7, 1000, Ljubljana, Slovenia
| | - Jan Tytgat
- University of Leuven (KU Leuven), Toxicology & Pharmacology, O&N2, PO Box 922, Herestraat 49, 3000, Leuven, Belgium
| | - Steve Peigneur
- University of Leuven (KU Leuven), Toxicology & Pharmacology, O&N2, PO Box 922, Herestraat 49, 3000, Leuven, Belgium
| | - Marc Rogers
- Metrion Biosciences Limited, Building 2, Granta Centre, Granta Park, Great Abington, Cambridge, CB21 6AL, UK
| | - Alexander Haworth
- Metrion Biosciences Limited, Building 2, Granta Centre, Granta Park, Great Abington, Cambridge, CB21 6AL, UK
| | - Robert W Kirby
- Metrion Biosciences Limited, Building 2, Granta Centre, Granta Park, Great Abington, Cambridge, CB21 6AL, UK
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Ruggiero SM, Xian J, Helbig I. The current landscape of epilepsy genetics: where are we, and where are we going? Curr Opin Neurol 2023; 36:86-94. [PMID: 36762645 PMCID: PMC10088099 DOI: 10.1097/wco.0000000000001141] [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] [Indexed: 02/11/2023]
Abstract
PURPOSE OF REVIEW In this review, we aim to analyse the progress in understanding the genetic basis of the epilepsies, as well as ongoing efforts to define the increasingly diverse and novel presentations, phenotypes and divergences from the expected that have continually characterized the field. RECENT FINDINGS A genetic workup is now considered to be standard of care for individuals with an unexplained epilepsy, due to mounting evidence that genetic diagnoses significantly influence treatment choices, prognostication, community support, and increasingly, access to clinical trials. As more individuals with epilepsy are tested, novel presentations of known epilepsy genes are being discovered, and more individuals with self-limited epilepsy are able to attain genetic diagnoses. In addition, new genes causative of epilepsy are being uncovered through both traditional and novel methods, including large international data-sharing collaborations and massive sequencing efforts as well as computational methods and analyses driven by the Human Phenotype Ontology (HPO). SUMMARY New approaches to gene discovery and characterization are advancing rapidly our understanding of the genetic and phenotypic architecture of the epilepsies. This review highlights relevant and groundbreaking studies published recently that have pushed forward the field of epilepsy genetics.
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Affiliation(s)
- Sarah M Ruggiero
- 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, 19146, USA
| | - Julie Xian
- 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, 19146, 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, 19146, USA
- Department of Neurology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, 19104, USA
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Structure and Function of Sodium Channel Nav1.3 in Neurological Disorders. Cell Mol Neurobiol 2023; 43:575-584. [PMID: 35332400 DOI: 10.1007/s10571-022-01211-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 03/07/2022] [Indexed: 11/03/2022]
Abstract
Nav1.3, encoded by the SCN3A gene, is a voltage-gated sodium channel on the cell membrane. It is expressed abundantly in the fetal brain but little in the normal adult brain. It is involved in the generation and conduction of action potentials in excitable cells. Nav1.3 plays an important role in many neurological diseases. The aim of this review is to summarize new findings about Nav1.3 in the field of neurology. Many mutations of SCN3A can lead to neuronal hyperexcitability and then cause epilepsy. The rapid recovery from inactivation and slow closed-state inactivation kinetics of Nav1.3 leads to a reduced activation threshold of the channel and a high frequency of firing of neurons. Hyperactivity of Nav1.3 also induces increased excitability of sensory neurons, a lower nociceptive threshold, and neuropathic pain. This review summarizes the structure and the function of Nav1.3 and focuses on its relationship with epilepsy and neuropathic pain.
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Duc NM, Thu NTM, Bui CB, Hoa G, Le Trung Hieu N. Genotype and phenotype characteristics of West syndrome in 20 Vietnamese children: Two novel variants detected by next-generation sequencing. Epilepsy Res 2023; 190:107094. [PMID: 36689859 DOI: 10.1016/j.eplepsyres.2023.107094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 01/16/2023] [Accepted: 01/19/2023] [Indexed: 01/21/2023]
Abstract
BACKGROUND In children with West syndrome (WS), whose treatment is challenging due to drug resistance and poor prognosis, investigation of genetic etiology and genotype-phenotype characteristics might assist in treatment optimization and genetic counseling. OBJECTIVE In this study, we aimed to present the results of genetic analysis and the corresponding phenotypes in a cohort of twenty children with WS in Vietnam. METHODS Our study was designed as a single-institution retrospective case series, in which consecutive sampling was used to select WS children having undergone genetic testing. Identified variants were investigated individually or as a variant combination by bioinformatics platforms. Clinical data were used to establish the genotype-phenotype correlation and compare clinical characteristics between groups of genetic causes and unknown causes. RESULTS Genetic testing identified at least one variant in 17/20 children. According to ACMG 2015, of all variants, one variant (3.9%) was classified as a benign variant, 16 variants (61.5%) were variants of uncertain significance, 4 (15.4%) were likely pathogenic variants, and 5 (19.2%) were pathogenic variants. These 26 variants belonged to 21 genes, of which eight candidate genes were CREBBP, MED25, HDAC8, SCN3A, ABCD1, TSC2, COL4A1, and NDUFA10. Two novel variants of SCN3A and TSC2 were found. Predicted pathogenic variant combinations were identified in two cases. Compared to three children of unknown etiology, five children with genetic causes had a higher rate of abnormal brain structures, developmental delay, and treatment resistance. CONCLUSIONS WS has a genetically heterogeneous etiology, and some cases might be polygenically susceptible. Our findings expand the disease's genotype-phenotype spectrum and support previous literature results that genetic etiology poses an unfavorable outcome in WS.
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Affiliation(s)
- Nguyen Minh Duc
- Neurology Department, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City 70000, Vietnam.
| | - Nguyen Thuy Minh Thu
- Neurology Department, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City 70000, Vietnam; Neurology Department, Children Hospital 2, Ho Chi Minh City 70000, Vietnam.
| | - Chi-Bao Bui
- School of Medicine, Vietnam National University, Ho Chi Minh City 70701, Vietnam.
| | - Giang Hoa
- Medical Genetics Institute, Ho Chi Minh City 70000, Vietnam.
| | - Nguyen Le Trung Hieu
- Neurology Department, University of Medicine and Pharmacy at Ho Chi Minh City, Ho Chi Minh City 70000, Vietnam; Neurology Department, Children Hospital 2, Ho Chi Minh City 70000, Vietnam.
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Guo QB, Zhan L, Xu HY, Gao ZB, Zheng YM. SCN8A epileptic encephalopathy mutations display a gain-of-function phenotype and divergent sensitivity to antiepileptic drugs. Acta Pharmacol Sin 2022; 43:3139-3148. [PMID: 35902765 PMCID: PMC9712530 DOI: 10.1038/s41401-022-00955-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 07/05/2022] [Indexed: 11/09/2022] Open
Abstract
De novo missense mutations in SCN8A gene encoding voltage-gated sodium channel NaV1.6 are linked to a severe form of early infantile epileptic encephalopathy named early infantile epileptic encephalopathy type13 (EIEE13). The majority of the patients with EIEE13 does not respond favorably to the antiepileptic drugs (AEDs) in clinic and has a significantly increased risk of death. Although more than 60 EIEE13-associated mutations have been discovered, only few mutations have been functionally analyzed. In this study we investigated the functional influences of mutations N1466T and N1466K, two EIEE13-associated mutations located in the inactivation gate, on sodium channel properties. Sodium currents were recorded from CHO cells expressing the mutant and wide-type (WT) channels using the whole-cell patch-clamp technique. We found that, in comparison with WT channels, both the mutant channels exhibited increased window currents, persistent currents (INaP) and ramp currents, suggesting that N1466T and N1466K were gain-of-function (GoF) mutations. Sodium channel inhibition is one common mechanism of currently available AEDs, in which topiramate (TPM) was effective in controlling seizures of patients carrying either of the two mutations. We found that TPM (100 µM) preferentially inhibited INaP and ramp currents but did not affect transient currents (INaT) mediated by N1466T or N1466K. Among the other 6 sodium channel-inhibiting AEDs tested, phenytoin and carbamazepine displayed greater efficacy than TPM in suppressing both INaP and ramp currents. Functional characterization of mutants N1466T and N1466K is beneficial for understanding the pathogenesis of EIEE13. The divergent effects of sodium channel-inhibiting AEDs on INaP and ramp currents provide insight into the development of therapeutic strategies for the N1466T and N1466K-associated EIEE13.
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Affiliation(s)
- Qian-Bei Guo
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Li Zhan
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Hai-Yan Xu
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China
| | - Zhao-Bing Gao
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
- Zhongshan Institute for Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Zhongshan, 528437, China.
| | - Yue-Ming Zheng
- Center for Neurological and Psychiatric Research and Drug Discovery, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, 201203, China.
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11
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Alghamdi MA, Al-Eitan LN, Asiri A, Rababa'h DM, Alqahtani SA, Aldarami MS, Alsaeedi MA, Almuidh RS, Alzahrani AA, Sakah AH, El Nashar EM, Otaif MY, Abdel Ghaffar NF. Association of sodium voltage-gated channel genes polymorphisms with epilepsy risk and prognosis in the Saudi population. Ann Med 2022; 54:1938-1951. [PMID: 35801810 PMCID: PMC9367647 DOI: 10.1080/07853890.2022.2096257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Epilepsy is a heterogeneous complex condition that involve the human brain. Genetic predisposition to epilepsy is a fundamental factor of the disorder aetiology. The sodium voltage-gated channel (SCN) genes variants are critical biomarker for the epilepsy development and progression. In this study, we aimed to investigate the association of several SNCs genetic polymorphisms with epilepsy risk and their intrudance of the disease prognosis. METHODS Blood samples were withdrawn from 296 Epilepsy patients in addition to 293 healthy matched participants prior to DNA extraction. PCR-sequencing was used for genotyping analysis. Genotyping outputs were then statistically analysed for genotype/phenotype evaluation. RESULTS Within SCN1A gene we found that the rs6432861 (p = 0.014) was in correlation with the risk of epilepsy. In addition, both rs4667485 and rs1469649 of SCN2A gene were significantly correlated to epilepsy risk for both allelic (4e-4 and 1e-3) and genotypic (1e-3 and 5e-3). Moreover, the haplotype analysis showed that the GATGCTCGGTTTCGCTACGCA haplotype of SCN2A gene was significantly related to epilepsy increased risk, p = 6e-3, OR (CI) = 2.02 (1.23-3.31). In relevant to our finding, many of the investigated SCNs variants in the current study were related to several clinical features of epilepsy. CONCLUSION In light of our results, we infer that SCN genes polymorphisms are strong candidates for epilepsy development and progression. Furthermore, these variant are essential for the disorder prognosis and medications outcomes.Key MessagesGenetic polymorphisms of sodium channels SCN1A, SCN2A and SCN3A were found to be associated with the risk of epilepsy.SCN1B polymorphisms were found to be correlated to epilepsy reduced risk.SCNs variants are involved in the epilepsy prognosis and response to treatment.
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Affiliation(s)
- Mansour A Alghamdi
- Department of Anatomy, College of Medicine, King Khalid University, Abha, Saudi Arabia.,Genomics and Personalized Medicine Unit, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Laith N Al-Eitan
- Department of Applied Biological Sciences, Jordan University of Science and Technology, Irbid, Jordan.,Department of Biotechnology and Genetic Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Ashwag Asiri
- Department of Child Health, College of Medicine, King Khalid University, Abha, Saudi Arabia
| | - Doaa M Rababa'h
- Department of Applied Biological Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Sultan A Alqahtani
- Neurology Department, Neuroscience Centre, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Mohammed S Aldarami
- Neurology Department, Neuroscience Centre, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Manar A Alsaeedi
- Neurology Department, Neuroscience Centre, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Raghad S Almuidh
- Neurology Department, Neuroscience Centre, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Abdulbari A Alzahrani
- Neurology Department, Neuroscience Centre, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Ahmad H Sakah
- College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Eman Mohamad El Nashar
- Department of Anatomy, College of Medicine, King Khalid University, Abha, Saudi Arabia.,Department of Histology and Cell Biology, Faculty of Medicine, Benha University, Benha, Egypt
| | - Mansour Y Otaif
- Department of Pediatric, Neurology section, Abha Maternity and Childern Hospital, Abha, Saudi Arabia
| | - Nawal F Abdel Ghaffar
- Neurology Department, Kasr Al Ainy Hospital, Faculty of Medicine, Cairo University, Giza, Egypt.,Neurology Department, Aseer Central Hospital, Abha, Saudi Arabia
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12
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Brunklaus A, Brünger T, Feng T, Fons C, Lehikoinen A, Panagiotakaki E, Vintan MA, Symonds J, Andrew J, Arzimanoglou A, Delima S, Gallois J, Hanrahan D, Lesca G, MacLeod S, Marjanovic D, McTague A, Nuñez-Enamorado N, Perez-Palma E, Scott Perry M, Pysden K, Russ-Hall SJ, Scheffer IE, Sully K, Syrbe S, Vaher U, Velayutham M, Vogt J, Weiss S, Wirrell E, Zuberi SM, Lal D, Møller RS, Mantegazza M, Cestèle S. The gain of function SCN1A disorder spectrum: novel epilepsy phenotypes and therapeutic implications. Brain 2022; 145:3816-3831. [PMID: 35696452 PMCID: PMC9679167 DOI: 10.1093/brain/awac210] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 04/14/2022] [Accepted: 05/26/2022] [Indexed: 11/29/2022] Open
Abstract
Brain voltage-gated sodium channel NaV1.1 (SCN1A) loss-of-function variants cause the severe epilepsy Dravet syndrome, as well as milder phenotypes associated with genetic epilepsy with febrile seizures plus. Gain of function SCN1A variants are associated with familial hemiplegic migraine type 3. Novel SCN1A-related phenotypes have been described including early infantile developmental and epileptic encephalopathy with movement disorder, and more recently neonatal presentations with arthrogryposis. Here we describe the clinical, genetic and functional evaluation of affected individuals. Thirty-five patients were ascertained via an international collaborative network using a structured clinical questionnaire and from the literature. We performed whole-cell voltage-clamp electrophysiological recordings comparing sodium channels containing wild-type versus variant NaV1.1 subunits. Findings were related to Dravet syndrome and familial hemiplegic migraine type 3 variants. We identified three distinct clinical presentations differing by age at onset and presence of arthrogryposis and/or movement disorder. The most severely affected infants (n = 13) presented with congenital arthrogryposis, neonatal onset epilepsy in the first 3 days of life, tonic seizures and apnoeas, accompanied by a significant movement disorder and profound intellectual disability. Twenty-one patients presented later, between 2 weeks and 3 months of age, with a severe early infantile developmental and epileptic encephalopathy and a movement disorder. One patient presented after 3 months with developmental and epileptic encephalopathy only. Associated SCN1A variants cluster in regions of channel inactivation associated with gain of function, different to Dravet syndrome variants (odds ratio = 17.8; confidence interval = 5.4-69.3; P = 1.3 × 10-7). Functional studies of both epilepsy and familial hemiplegic migraine type 3 variants reveal alterations of gating properties in keeping with neuronal hyperexcitability. While epilepsy variants result in a moderate increase in action current amplitude consistent with mild gain of function, familial hemiplegic migraine type 3 variants induce a larger effect on gating properties, in particular the increase of persistent current, resulting in a large increase of action current amplitude, consistent with stronger gain of function. Clinically, 13 out of 16 (81%) gain of function variants were associated with a reduction in seizures in response to sodium channel blocker treatment (carbamazepine, oxcarbazepine, phenytoin, lamotrigine or lacosamide) without evidence of symptom exacerbation. Our study expands the spectrum of gain of function SCN1A-related epilepsy phenotypes, defines key clinical features, provides novel insights into the underlying disease mechanisms between SCN1A-related epilepsy and familial hemiplegic migraine type 3, and identifies sodium channel blockers as potentially efficacious therapies. Gain of function disease should be considered in early onset epilepsies with a pathogenic SCN1A variant and non-Dravet syndrome phenotype.
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Affiliation(s)
- Andreas Brunklaus
- Correspondence to: Professor Andreas Brunklaus, MD Institute of Health and Wellbeing University of Glasgow Paediatric Neurosciences Research Group Office Block, Ground Floor, Zone 2 Royal Hospital for Children 1345 Govan Road, Glasgow G51 4TF, UK E-mail:
| | - Tobias Brünger
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
| | - Tony Feng
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Member of the ERN EpiCARE, Glasgow, UK
| | - Carmen Fons
- Pediatric Neurology Department, CIBERER-ISCIII, Sant Joan de Déu Universitary Hospital, Institut de Recerca Sant Joan de Déu, Member of the ERN EpiCARE, Barcelona, Spain
| | - Anni Lehikoinen
- Pediatric Neurology Department, Kuopio University Hospital, Member of the ERN EpiCARE, Kuopio, Finland
| | - Eleni Panagiotakaki
- Department of Paediatric Clinical Epileptology, sleep disorders and functional neurology, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL) and Inserm U1028/CNRS UMR5292, Lyon, France
| | - Mihaela-Adela Vintan
- ‘Iuliu Hatieganu’ University of Medicine and Pharmacy, Faculty of Medicine, Department of Neuroscience, Neurology and Pediatric Neurology, Victor Babes, 43, 400012 Cluj-Napoca, Romania
| | - Joseph Symonds
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Member of the ERN EpiCARE, Glasgow, UK
| | - James Andrew
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Member of the ERN EpiCARE, Glasgow, UK
| | - Alexis Arzimanoglou
- Pediatric Neurology Department, CIBERER-ISCIII, Sant Joan de Déu Universitary Hospital, Institut de Recerca Sant Joan de Déu, Member of the ERN EpiCARE, Barcelona, Spain
- Department of Paediatric Clinical Epileptology, sleep disorders and functional neurology, Member of the ERN EpiCARE, University Hospitals of Lyon (HCL) and Inserm U1028/CNRS UMR5292, Lyon, France
| | - Sarah Delima
- Indiana University School of Medicine, IU Health Riley Hospital for Children, Department of Neurology, Division of Pediatric Neurology, Indianapolis, IN, USA
| | - Julie Gallois
- Louisiana State University Health Sciences Center School of Medicine, New Orleans, LA, USA
| | - Donncha Hanrahan
- Department of Paediatric Neurology, Royal Belfast Hospital for Sick Children, Belfast, UK
| | - Gaetan Lesca
- Department of Medical Genetics, Lyon University Hospital, Member of the ERN EpiCARE, Université Claude Bernard Lyon 1, Lyon, France
| | - Stewart MacLeod
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Member of the ERN EpiCARE, Glasgow, UK
| | - Dragan Marjanovic
- The Danish Epilepsy Centre, Member of the ERN EpiCARE, Dianalund, Denmark
| | - Amy McTague
- Developmental Neurosciences, UCL Great Ormond Street Institute of Child Health, London, UK
- Department of Neurology, Great Ormond Street Hospital for Children, Member of the ERN EpiCARE, London, UK
| | | | - Eduardo Perez-Palma
- Universidad del Desarrollo, Centro de Genética y Genómica, Facultad de Medicina Clínica Alemana, Santiago, Chile
| | - M Scott Perry
- Jane and John Justin Neurosciences Center, Cook Children’s Medical Center, Ft Worth, TX, USA
| | - Karen Pysden
- Paediatric Neurology Department, Leeds Teaching Hospitals, Leeds General Infirmary, Leeds, UK
| | - Sophie J Russ-Hall
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
- Florey Institute of Neuroscience and Mental Health, Melbourne, Australia
- Murdoch Children’s Research Institute and Department of Paediatrics, University of Melbourne, Royal Children’s Hospital, Melbourne, Australia
| | - Krystal Sully
- Baylor College of Medicine, Houston, TX, USA
- Texas Children’s Hospital, Houston, TX, USA
| | - Steffen Syrbe
- Division of Pediatric Epileptology, Center for Pediatrics and Adolescent Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Ulvi Vaher
- Children’s Clinic of Tartu University Hospital, Faculty of Medicine of Tartu University, Member of the ERN EpiCARE, Tartu, Estonia
| | | | - Julie Vogt
- West Midlands Regional Genetics Service, Birmingham Women’s and Children’s Hospital, Birmingham, UK
| | - Shelly Weiss
- Division of Neurology, SickKids, University of Toronto, Toronto, Canada
| | - Elaine Wirrell
- Divisions of Epilepsy and Child and Adolescent Neurology, Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Sameer M Zuberi
- Institute of Health and Wellbeing, University of Glasgow, Glasgow, UK
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Member of the ERN EpiCARE, Glasgow, UK
| | - Dennis Lal
- Cologne Center for Genomics, University of Cologne, Cologne, Germany
- Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, USA
- Stanley Center for Psychiatric Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Rikke S Møller
- Correspondence may also be addressed to: Professor Rikke Steensbjerre Møller, PhD E-mail: ; Professor Massimo Mantegazza, PhD E-mail: ; Professor Sandrine Cestèle, PhD E-mail:
| | - Massimo Mantegazza
- Correspondence may also be addressed to: Professor Rikke Steensbjerre Møller, PhD E-mail: ; Professor Massimo Mantegazza, PhD E-mail: ; Professor Sandrine Cestèle, PhD E-mail:
| | - Sandrine Cestèle
- Correspondence may also be addressed to: Professor Rikke Steensbjerre Møller, PhD E-mail: ; Professor Massimo Mantegazza, PhD E-mail: ; Professor Sandrine Cestèle, PhD E-mail:
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13
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Ahrari A, Meseke M, Förster E. Tetrodotoxin prevents heat-shock induced granule cell dispersion in hippocampal slice cultures. Front Cell Dev Biol 2022; 10:906262. [PMID: 36092698 PMCID: PMC9452958 DOI: 10.3389/fcell.2022.906262] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 08/01/2022] [Indexed: 11/15/2022] Open
Abstract
Granule cell dispersion (GCD) has been associated as a pathological feature of temporal lobe epilepsy (TLE). Early-life epileptiform activity such as febrile seizures has been proposed to have a causal link to developing chronic TLE. During postnatal development, the hippocampus may be particularly vulnerable to hyperexcitability-induced insults since neuronal migration and differentiation are still ongoing in the hippocampus. Further, the extracellular matrix (ECM), here in particular the protein reelin, has been implicated in the pathophysiology of GCD. Thus, loss of reelin-expressing cells, Cajal-Retzius cells and subsets of interneurons, may be related to GCD. To study the possible role of febrile seizures, we previously induced GCD in vitro by subjecting hippocampal slice cultures to a transient heat-shock, which was not accompanied by loss of Cajal-Retzius cells. In order to examine the mechanisms involved in heat-shock induced GCD, the present study aimed to determine whether such dispersion could be prevented by blocking cellular electrical activity. Here we show that the extent of heat-shock induced GCD could be significantly reduced by treatment with the sodium channel blocker tetrodotoxin (TTX), suggesting that electrical activity is an important factor involved in heat-shock induced GCD.
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14
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Johannesen KM, Gardella E, Ahring PK, Møller RS. De novo SCN3A missense variant associated with self-limiting generalized epilepsy with fever sensitivity. Eur J Med Genet 2022; 65:104577. [DOI: 10.1016/j.ejmg.2022.104577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Revised: 05/09/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022]
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15
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Fouda MA, Ghovanloo MR, Ruben PC. Late sodium current: incomplete inactivation triggers seizures, myotonias, arrhythmias, and pain syndromes. J Physiol 2022; 600:2835-2851. [PMID: 35436004 DOI: 10.1113/jp282768] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
Acquired and inherited dysfunction in voltage-gated sodium channels underlies a wide range of diseases. "In addition to the defects in trafficking and expression, sodium channelopathies are also caused by dysfunction in one or several gating properties, for instance activation or inactivation. Disruption of the channel inactivation leads to the increased late sodium current, which is a common defect in seizure disorders, cardiac arrhythmias skeletal muscle myotonia and pain. An increase in late sodium current leads to repetitive action potential in neurons and skeletal muscles, and prolonged action potential duration in the heart. In this topical review, we compare the effects of late sodium current in brain, heart, skeletal muscle, and peripheral nerves. Abstract figure legend Shows cartoon illustration of general Nav channel transitions between (1) resting, (2) open, and (3) fast inactivated states. Disruption of the inactivation process exacerbates (4) late sodium currents. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mohamed A Fouda
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada.,Department of Pharmacology and Toxicology, Alexandria University, Alexandria, Egypt
| | | | - Peter C Ruben
- Department of Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, Canada
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16
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Structural basis for modulation of human NaV1.3 by clinical drug and selective antagonist. Nat Commun 2022; 13:1286. [PMID: 35277491 PMCID: PMC8917200 DOI: 10.1038/s41467-022-28808-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 02/04/2022] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium (NaV) channels play fundamental roles in initiating and propagating action potentials. NaV1.3 is involved in numerous physiological processes including neuronal development, hormone secretion and pain perception. Here we report structures of human NaV1.3/β1/β2 in complex with clinically-used drug bulleyaconitine A and selective antagonist ICA121431. Bulleyaconitine A is located around domain I-II fenestration, providing the detailed view of the site-2 neurotoxin binding site. It partially blocks ion path and expands the pore-lining helices, elucidating how the bulleyaconitine A reduces peak amplitude but improves channel open probability. In contrast, ICA121431 preferentially binds to activated domain IV voltage-sensor, consequently strengthens the Ile-Phe-Met motif binding to its receptor site, stabilizes the channel in inactivated state, revealing an allosterically inhibitory mechanism of NaV channels. Our results provide structural details of distinct small-molecular modulators binding sites, elucidate molecular mechanisms of their action on NaV channels and pave a way for subtype-selective therapeutic development. NaV1.3 is involved in neuronal development, hormone secretion and pain perception. Here, the authors elucidate the molecular mechanism for modulation of NaV1.3 by a site-2 neurotoxin bulleyaconitine A and a subtype selective antagonist ICA121431.
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17
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Zimmern V, Minassian B, Korff C. A Review of Targeted Therapies for Monogenic Epilepsy Syndromes. Front Neurol 2022; 13:829116. [PMID: 35250833 PMCID: PMC8891748 DOI: 10.3389/fneur.2022.829116] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 01/13/2022] [Indexed: 11/15/2022] Open
Abstract
Genetic sequencing technologies have led to an increase in the identification and characterization of monogenic epilepsy syndromes. This increase has, in turn, generated strong interest in developing “precision therapies” based on the unique molecular genetics of a given monogenic epilepsy syndrome. These therapies include diets, vitamins, cell-signaling regulators, ion channel modulators, repurposed medications, molecular chaperones, and gene therapies. In this review, we evaluate these therapies from the perspective of their clinical validity and discuss the future of these therapies for individual syndromes.
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Affiliation(s)
- Vincent Zimmern
- Division of Child Neurology, University of Texas Southwestern, Dallas, TX, United States
- *Correspondence: Vincent Zimmern
| | - Berge Minassian
- Division of Child Neurology, University of Texas Southwestern, Dallas, TX, United States
| | - Christian Korff
- Pediatric Neurology Unit, University Hospitals, Geneva, Switzerland
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18
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Sodium channel expression and transcript variation in the developing brain of human, Rhesus monkey, and mouse. Neurobiol Dis 2022; 164:105622. [PMID: 35031483 DOI: 10.1016/j.nbd.2022.105622] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 01/06/2022] [Accepted: 01/07/2022] [Indexed: 12/16/2022] Open
Abstract
Genetic variation in voltage-gated sodium (NaV) channels is a significant contributor to neurodevelopmental disorders. NaV channel alpha subunits are encoded by the SCNxA family and four are predominately expressed in the brain: SCN1A, SCN2A, SCN3A, and SCN8A. Gene expression is developmentally regulated, and they are known to express functionally distinct transcript variants. Precision therapies targeting these genes and their transcript variants are currently in preclinical development, yet the developmental expression of these transcripts in the human brain is yet to be fully understood. Additionally, the functional consequences of some mutations differ depending on the studied channel isoform, suggesting differential transcript variant expression can affect disease prognoses. We characterise the expression of the four SCNxAs and their transcript variants in human, Rhesus monkey and mouse brain using publicly available RNA-sequencing data and analysis tools, demonstrating that this approach can be used to answer important biological questions of gene and transcript developmental regulation. We find that gene expression and transcript variant regulation are conserved across species at similar developmental stages and determine the developmental milestones for transcript variant expression. Our study provides a guide to researchers testing therapies and clinicians advising prognoses based on the expression of channel isoforms.
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19
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Xu C, Zhang Y, Gozal D, Carney P. Channelopathy of Dravet Syndrome and Potential Neuroprotective Effects of Cannabidiol. J Cent Nerv Syst Dis 2021; 13:11795735211048045. [PMID: 34992485 PMCID: PMC8724990 DOI: 10.1177/11795735211048045] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Dravet syndrome (DS) is a channelopathy, neurodevelopmental, epileptic encephalopathy characterized by seizures, developmental delay, and cognitive impairment that includes susceptibility to thermally induced seizures, spontaneous seizures, ataxia, circadian rhythm and sleep disorders, autistic-like behaviors, and premature death. More than 80% of DS cases are linked to mutations in genes which encode voltage-gated sodium channel subunits, SCN1A and SCN1B, which encode the Nav1.1α subunit and Nav1.1β1 subunit, respectively. There are other gene mutations encoding potassium, calcium, and hyperpolarization-activated cyclic nucleotide-gated (HCN) channels related to DS. One-third of patients have pharmacoresistance epilepsy. DS is unresponsive to standard therapy. Cannabidiol (CBD), a non-psychoactive phytocannabinoid present in Cannabis, has been introduced for treating DS because of its anticonvulsant properties in animal models and humans, especially in pharmacoresistant patients. However, the etiological channelopathiological mechanism of DS and action mechanism of CBD on the channels are unclear. In this review, we summarize evidence of the direct and indirect action mechanism of sodium, potassium, calcium, and HCN channels in DS, especially sodium subunits. Some channels' loss-of-function or gain-of-function in inhibitory or excitatory neurons determine the balance of excitatory and inhibitory are associated with DS. A great variety of mechanisms of CBD anticonvulsant effects are focused on modulating these channels, especially sodium, calcium, and potassium channels, which will shed light on ionic channelopathy of DS and the precise molecular treatment of DS in the future.
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Affiliation(s)
- Changqing Xu
- Department of Child Health and the Child Health Research Institute, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Yumin Zhang
- Department of Anatomy, Physiology and Genetics; Department of Neuroscience, Uniformed Services University School of Medicine, Bethesda, MD, USA
| | - David Gozal
- Department of Child Health and the Child Health Research Institute, School of Medicine, University of Missouri, Columbia, MO, USA
| | - Paul Carney
- Departments of Child Health and Neurology, School of Medicine, University of Missouri, Columbia, MO, USA
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20
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Koene LM, Niggl E, Wallaard I, Proietti-Onori M, Rotaru DC, Elgersma Y. Identifying the temporal electrophysiological and molecular changes that contribute to TSC-associated epileptogenesis. JCI Insight 2021; 6:150120. [PMID: 34877936 PMCID: PMC8675202 DOI: 10.1172/jci.insight.150120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 10/27/2021] [Indexed: 11/17/2022] Open
Abstract
Tuberous sclerosis complex (TSC), caused by heterozygous mutations in TSC1 or TSC2, frequently results in intractable epilepsy. Here, we made use of an inducible Tsc1-knockout mouse model, allowing us to study electrophysiological and molecular changes of Tsc1-induced epileptogenesis over time. We recorded from pyramidal neurons in the hippocampus and somatosensory cortex (L2/L3) and combined this with an analysis of transcriptome changes during epileptogenesis. Deletion of Tsc1 resulted in hippocampus-specific changes in excitability and adaptation, which emerged before seizure onset and progressed over time. All phenotypes were rescued after early treatment with rapamycin, an mTOR inhibitor. Later in epileptogenesis, we observed a hippocampal increase of excitation-to-inhibition ratio. These cellular changes were accompanied by dramatic transcriptional changes, especially after seizure onset. Most of these changes were rescued upon rapamycin treatment. Of the genes encoding ion channels or belonging to the Gene Ontology term action potential, 27 were differentially expressed just before seizure onset, suggesting a potential driving role in epileptogenesis. Our data highlight the complex changes driving epileptogenesis in TSC, including the changed expression of multiple ion channels. Our study emphasizes inhibition of the TSC/mTOR signaling pathway as a promising therapeutic approach to target epilepsy in patients with TSC.
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Balestrini S, Guerrini R, Sisodiya SM. Rare and Complex Epilepsies from Childhood to Adulthood: Requirements for Separate Management or Scope for a Lifespan Holistic Approach? Curr Neurol Neurosci Rep 2021; 21:65. [PMID: 34817708 PMCID: PMC8613076 DOI: 10.1007/s11910-021-01154-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/28/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE In this descriptive review, we describe current models of transition in rare and complex epilepsy syndromes and propose alternative approaches for more holistic management based on disease biology. RECENT FINDINGS Previously published guidance and recommendations on transition strategies in individuals with epilepsy have not been systematically and uniformly applied. There is significant heterogeneity in models of transition/transfer of care across countries and even within the same country. We provide examples of the most severe epilepsy and related syndromes and emphasise the limited data on their outcome in adulthood. Rare and complex epilepsy syndromes have unique presentations and require high levels of expertise and multidisciplinary approach. Lifespan clinics, with no transition, but instead continuity of care from childhood to adulthood with highly specialised input from healthcare providers, may represent an alternative effective approach. Effectiveness should be measured by evaluation of quality of life for both patients and their families/caregivers.
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Affiliation(s)
- Simona Balestrini
- Department of Clinical and Experimental Epilepsy, University College of London (UCL) Queen Square Institute of Neurology, London WC1N 3BG and Chalfont Centre for Epilepsy, London, Bucks, UK.
- Neuroscience Department, Meyer Children's Hospital, European Reference Network ERN EpiCARE, 50139, Florence, Italy.
| | - Renzo Guerrini
- Neuroscience Department, Meyer Children's Hospital, European Reference Network ERN EpiCARE, 50139, Florence, Italy
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, University College of London (UCL) Queen Square Institute of Neurology, London WC1N 3BG and Chalfont Centre for Epilepsy, London, Bucks, UK
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22
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Beck VC, Isom LL, Berg AT. Gastrointestinal Symptoms and Channelopathy-Associated Epilepsy. J Pediatr 2021; 237:41-49.e1. [PMID: 34181986 PMCID: PMC8478841 DOI: 10.1016/j.jpeds.2021.06.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 05/28/2021] [Accepted: 06/11/2021] [Indexed: 12/16/2022]
Abstract
OBJECTIVE To determine the prevalence of and identify factors associated with gastrointestinal (GI) symptoms among children with channelopathy-associated developmental and epileptic encephalopathy (DEE). STUDY DESIGN Parents of 168 children with DEEs linked to SCN1A (n = 59), KCNB1 (n = 31), or KCNQ2 (n = 78) completed online CLIRINX surveys about their children's GI symptoms. Our analysis examined the prevalence, frequency, and severity of GI symptoms, as well as DEE type, functional mobility, feeding difficulties, ketogenic diet, antiseizure medication, autism spectrum disorder (ASD), and seizures. Statistical analyses included the χ2 test, Wilcoxon rank-sum analysis, and multiple logistic regression. RESULTS GI symptoms were reported in 92 of 168 patients (55%), among whom 63 of 86 (73%) reported daily or weekly symptoms, 29 of 92 (32%) had frequent or serious discomfort, and 13 of 91 (14%) had frequent or serious appetite disturbances as a result. The prevalence of GI symptoms varied across DEE cohorts with 44% of SCN1A-DEE patients, 35% of KCNB1-DEE patients, and 71% of KCNQ2-DEE patients reporting GI symptoms in the previous month. After adjustment for DEE type, current use of ketogenic diet (6% reported), and gastrostomy tube (13% reported) were both associated with GI symptoms in a statistically, but not clinically, significant manner (P < .05). Patient age, functional mobility, feeding difficulties, ASD, and seizures were not clearly associated with GI symptoms. Overall, no individual antiseizure medication was significantly associated with GI symptoms across all DEE cohorts. CONCLUSIONS GI symptoms are common and frequently severe in patients with DEE.
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Affiliation(s)
- Veronica C Beck
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI; Department of Pharmacology, University of Michigan, Ann Arbor, MI
| | - Lori L Isom
- Neuroscience Graduate Program, University of Michigan, Ann Arbor, MI; Department of Pharmacology, University of Michigan, Ann Arbor, MI; Department of Neurology, University of Michigan, Ann Arbor, MI; Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Anne T Berg
- Division of Neurology, Epilepsy Center, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL; Department of Pediatrics, Northwestern Feinberg School of Medicine, Chicago, IL.
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23
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Liang L, Fazel Darbandi S, Pochareddy S, Gulden FO, Gilson MC, Sheppard BK, Sahagun A, An JY, Werling DM, Rubenstein JLR, Sestan N, Bender KJ, Sanders SJ. Developmental dynamics of voltage-gated sodium channel isoform expression in the human and mouse brain. Genome Med 2021; 13:135. [PMID: 34425903 PMCID: PMC8383430 DOI: 10.1186/s13073-021-00949-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 08/05/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genetic variants in the voltage-gated sodium channels SCN1A, SCN2A, SCN3A, and SCN8A are leading causes of epilepsy, developmental delay, and autism spectrum disorder. The mRNA splicing patterns of all four genes vary across development in the rodent brain, including mutually exclusive copies of the fifth protein-coding exon detected in the neonate (5N) and adult (5A). A second pair of mutually exclusive exons is reported in SCN8A only (18N and 18A). We aimed to quantify the expression of individual exons in the developing human brain. METHODS RNA-seq data from 783 human brain samples across development were analyzed to estimate exon-level expression. Developmental changes in exon utilization were validated by assessing intron splicing. Exon expression was also estimated in RNA-seq data from 58 developing mouse neocortical samples. RESULTS In the mature human neocortex, exon 5A is consistently expressed at least 4-fold higher than exon 5N in all four genes. For SCN2A, SCN3A, and SCN8A, a brain-wide synchronized 5N to 5A transition occurs between 24 post-conceptual weeks (2nd trimester) and 6 years of age. In mice, the equivalent 5N to 5A transition begins at or before embryonic day 15.5. In SCN8A, over 90% of transcripts in the mature human cortex include exon 18A. Early in fetal development, most transcripts include 18N or skip both 18N and 18A, with a transition to 18A inclusion occurring from 13 post-conceptual weeks to 6 months of age. No other protein-coding exons showed comparably dynamic developmental trajectories. CONCLUSIONS Exon usage in SCN1A, SCN2A, SCN3A, and SCN8A changes dramatically during human brain development. These splice isoforms, which alter the biophysical properties of the encoded channels, may account for some of the observed phenotypic differences across development and between specific variants. Manipulation of the proportion of splicing isoforms at appropriate stages of development may act as a therapeutic strategy for specific mutations or even epilepsy in general.
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Affiliation(s)
- Lindsay Liang
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Siavash Fazel Darbandi
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Sirisha Pochareddy
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Forrest O Gulden
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Michael C Gilson
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Brooke K Sheppard
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Atehsa Sahagun
- Department of Neurology, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Joon-Yong An
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, 02841, Republic of Korea
| | - Donna M Werling
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - John L R Rubenstein
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Nenad Sestan
- Department of Neuroscience and Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT, 06510, USA
- Program in Cellular Neuroscience, Neurodegeneration, and Repair and Yale Child Study Center, Yale School of Medicine, New Haven, CT, 06510, USA
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT, 06520, USA
- Department of Genetics, Yale University School of Medicine, New Haven, CT, 06520, USA
- Department of Comparative Medicine, Program in Integrative Cell Signaling and Neurobiology of Metabolism, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Kevin J Bender
- Department of Neurology, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA
| | - Stephan J Sanders
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94158, USA.
- Institute for Human Genetics, University of California, San Francisco, San Francisco, CA, 94158, USA.
- Bakar Computational Health Sciences Institute, University of California, San Francisco, San Francisco, CA, 94158, USA.
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Abstract
The presence of unprovoked, recurrent seizures, particularly when drug resistant and associated with cognitive and behavioral deficits, warrants investigation for an underlying genetic cause. This article provides an overview of the major classes of genes associated with epilepsy phenotypes divided into functional categories along with the recommended work-up and therapeutic considerations. Gene discovery in epilepsy supports counseling and anticipatory guidance but also opens the door for precision medicine guiding therapy with a focus on those with disease-modifying effects.
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Affiliation(s)
- Luis A Martinez
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Yi-Chen Lai
- Department of Pediatrics, Section of Pediatric Critical Care Medicine, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - J Lloyd Holder
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA
| | - Anne E Anderson
- Department of Pediatrics, Section of Pediatric Neurology and Developmental Neuroscience, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, 1250 Moursund Drive, Houston, TX 77030, USA.
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25
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New avenues in molecular genetics for the diagnosis and application of therapeutics to the epilepsies. Epilepsy Behav 2021; 121:106428. [PMID: 31400936 DOI: 10.1016/j.yebeh.2019.07.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/14/2019] [Accepted: 07/06/2019] [Indexed: 11/22/2022]
Abstract
Genetic epidemiology studies have shown that most epilepsies involve some genetic cause. In addition, twin studies have helped strengthen the hypothesis that in most patients with epilepsy, a complex inheritance is involved. More recently, with the development of high-density single-nucleotide polymorphism (SNP) microarrays and next-generation sequencing (NGS) technologies, the discovery of genes related to the epilepsies has accelerated tremendously. Especially, the use of whole exome sequencing (WES) has had a considerable impact on the identification of rare genetic variants with large effect sizes, including inherited or de novo mutations in severe forms of childhood epilepsies. The identification of pathogenic variants in patients with these childhood epilepsies provides many benefits for patients and families, such as the confirmation of the genetic nature of the diseases. This process will allow for better genetic counseling, more accurate therapy decisions, and a significant positive emotional impact. However, to study the genetic component of the more common forms of epilepsy, the use of high-density SNP arrays in genome-wide association studies (GWAS) seems to be the strategy of choice. As such, researchers can identify loci containing genetic variants associated with the common forms of epilepsy. The knowledge generated over the past two decades about the effects of the mutations that cause the monogenic epilepsy is tremendous; however, the scientific community is just starting to apply this information in order to generate better target treatments.
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26
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Taleb A, Zhou YP, Meng LT, Zhu MY, Zhang Q, Naveed M, Li LD, Wang P, Zhou QG, Meng F, Han F. New application of an old drug proparacaine in treating epilepsy via liposomal hydrogel formulation. Pharmacol Res 2021; 169:105636. [PMID: 33932606 DOI: 10.1016/j.phrs.2021.105636] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/16/2021] [Accepted: 04/20/2021] [Indexed: 01/06/2023]
Abstract
Proparacaine (PPC) is a previously discovered topical anesthetic for ophthalmic optometry and surgery by blocking the central Nav1.3. In this study, we found that proparacaine hydrochloride (PPC-HCl) exerted an acute robust antiepileptic effect in pilocarpine-induced epilepsy mice. More importantly, chronic treatment with PPC-HCl totally terminated spontaneous recurrent seizure occurrence without significant toxicity. Chronic treatment with PPC-HCl did not cause obvious cytotoxicity, neuropsychiatric adverse effects, hepatotoxicity, cardiotoxicity, and even genotoxicity that evaluated by whole genome-scale transcriptomic analyses. Only when in a high dose (50 mg/kg), the QRS interval measured by electrocardiography was slightly prolonged, which was similar to the impact of levetiracetam. Nevertheless, to overcome this potential issue, we adopt a liposome encapsulation strategy that could alleviate cardiotoxicity and prepared a type of hydrogel containing PPC-HCl for sustained release. Implantation of thermosensitive chitosan-based hydrogel containing liposomal PPC-HCl into the subcutaneous tissue exerted immediate and long-lasting remission from spontaneous recurrent seizure in epileptic mice without affecting QRS interval. Therefore, this new liposomal hydrogel formulation of proparacaine could be developed as a transdermal patch for treating epilepsy, avoiding the severe toxicity after chronic treatment with current antiepileptic drugs in clinic.
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Affiliation(s)
- Abdoh Taleb
- Key Lab of Cardiovascular and Cerebrovascular Medicine, Drug Target and Drug Discovery Center, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Ya-Ping Zhou
- Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Ling-Tong Meng
- Key Lab of Cardiovascular and Cerebrovascular Medicine, Drug Target and Drug Discovery Center, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Ming-Yi Zhu
- Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Qiao Zhang
- Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Muhammad Naveed
- Key Lab of Cardiovascular and Cerebrovascular Medicine, Drug Target and Drug Discovery Center, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Lian-Di Li
- Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Peng Wang
- State Key Laboratory of Translational Medicine and Innovative Drug Development, Jiangsu Simcere Pharmaceutical Co., Ltd., Nanjing 210042, China
| | - Qi-Gang Zhou
- Key Lab of Cardiovascular and Cerebrovascular Medicine, Drug Target and Drug Discovery Center, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; Sir Run Run Hospital, Nanjing Medical University, Nanjing 211166, Jiangsu Province, China.
| | - Fan Meng
- Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; State Key Laboratory of Translational Medicine and Innovative Drug Development, Jiangsu Simcere Pharmaceutical Co., Ltd., Nanjing 210042, China.
| | - Feng Han
- Key Lab of Cardiovascular and Cerebrovascular Medicine, Drug Target and Drug Discovery Center, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China; Department of Clinical Pharmacology, School of Pharmacy, Nanjing Medical University, Nanjing 211166, China.
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27
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Li W, Zhao W, Wang J, Zhang X, Qian X, Gu R, He G. Identification of a novel variant p.Ser606Gly in SCN3A associated with childhood absence epilepsy. Epilepsy Res 2021; 175:106682. [PMID: 34102392 DOI: 10.1016/j.eplepsyres.2021.106682] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/14/2021] [Accepted: 05/31/2021] [Indexed: 10/21/2022]
Abstract
Sodium (Na+) channels are the basis for action potential generation and propagation, which play a key role in the regulation of neuronal excitability. SCN3A is a gene encoding for sodium channel protein type 3 subunit alpha (or known as Nav1.3). This study aimed to explore SCN3A genetic variants in a cohort of childhood absence epilepsy (CAE) via whole exome sequencing. A novel SCN3A missense variant (c.A1816G, p.Ser606Gly) was identified in a patient with CAE. This variant had not been reported in both 1000G and ExAC databases. Bioinformatics analysis revealed that this variant was pathogenic and could transform the protein structure of Nav1.3. The reported phenotypes of SCN3A-related central nerve system disorders included multiple seizure types, polymicrogyria and different degrees of developmental delay/intellectual disability. The patient with p.Ser606Gly variant exhibited typical absence seizures. The MRI and CT scan results were normal, and EEG showed that 3-Hz spike-slow wave discharges. In conclusion, our findings not only broaden the pathogenic spectrum of SCN3A, but also extend the clinical phenotypes of SCN3A-related CAE.
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Affiliation(s)
- Wei Li
- School of Forensic Medicine, Xinxiang Medical University, Xinxiang, China
| | - Wenli Zhao
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
| | - Jing Wang
- School of Forensic Medicine, Xinxiang Medical University, Xinxiang, China
| | - Xiaoli Zhang
- Department of Neurology, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Xinlai Qian
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China.
| | - Renjun Gu
- Department of Neurology, The Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, China.
| | - Guoyang He
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China.
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28
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Ithal D, Sukumaran SK, Bhattacharjee D, Vemula A, Nadella R, Mahadevan J, Sud R, Viswanath B, Purushottam M, Jain S. Exome hits demystified: The next frontier. Asian J Psychiatr 2021; 59:102640. [PMID: 33892377 DOI: 10.1016/j.ajp.2021.102640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/26/2021] [Indexed: 12/13/2022]
Abstract
Severe mental illnesses such as schizophrenia and bipolar disorder have complex inheritance patterns, involving both common and rare variants. Whole exome sequencing is a promising approach to find out the rare genetic variants. We had previously reported several rare variants in multiplex families with severe mental illnesses. The current article tries to summarise the biological processes and pattern of expression of genes harbouring the aforementioned variants, linking them to known clinical manifestations through a methodical narrative review. Of the 28 genes considered for this review from 7 families with multiple affected individuals, 6 genes are implicated in various neuropsychiatric manifestations including some variations in the brain morphology assessed by magnetic resonance imaging. Another 15 genes, though associated with neuropsychiatric manifestations, did not have established brain morphological changes whereas the remaining 7 genes did not have any previously recorded neuropsychiatric manifestations at all. Wnt/b-catenin signaling pathway was associated with 6 of these genes and PI3K/AKT, calcium signaling, ERK, RhoA and notch signaling pathways had at least 2 gene associations. We present a comprehensive review of biological and clinical knowledge about the genes previously reported in multiplex families with severe mental illness. A 'disease in dish approach' can be helpful to further explore the fundamental mechanisms.
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Affiliation(s)
- Dhruva Ithal
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Salil K Sukumaran
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Debanjan Bhattacharjee
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Alekhya Vemula
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Ravi Nadella
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Jayant Mahadevan
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Reeteka Sud
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Biju Viswanath
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Meera Purushottam
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India.
| | - Sanjeev Jain
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
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29
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Ma H, Guo Y, Chen Z, Wang L, Tang Z, Zhang J, Miao Q, Zhai Q. Mutations in the sodium channel genes SCN1A, SCN3A, and SCN9A in children with epilepsy with febrile seizures plus(EFS+). Seizure 2021; 88:146-152. [PMID: 33895391 DOI: 10.1016/j.seizure.2021.04.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To explore disease-causing gene mutations of epilepsy with febrile seizures plus (EFS+) in Southern Chinese Han population. METHODS Blood samples and clinical data were collected from 49 Southern Han Chinese patients with EFS+. Gene screening was performed using whole-exome sequencing and panel sequencing for 485 epilepsy-related genes. The pathogenicity of variants was evaluated based on ACMG scoring and assessment of clinical concordance. RESULTS We identified 10 putatively causative sodium channel gene variants in 49 patients with EFS+, including 8 variants in SCN1A (R500Q appeared twice), one in SCN3A and one in SCN9A. All these missense mutations were inherited from maternal or paternal and were evaluated to be of uncertain significance according to ACMG. The clinical features of patients were in concordance with the EFS+ phenotype of the mutated SCN1A, SCN3A and SCN9A gene. The clinical phenotypes of 11 probands with these gene variants included febrile seizures plus (FS+, n=7), Dravet Syndrome (n=3), FS+ with focal seizures (n=1). Three probands with SCN1A variants (R500Q located in the non-voltage areas, or G1711D in the pore-forming domain) developed severe Dravet syndrome. The affected individuals with the other 6 SCN1A variants located outside the pore-forming domain showed mild phenotypes. Novel SCN3A variant ((D1688Y) and SCN9A variant (R185H) were identified in two probands respectively and both of the probands had FS+. CONCLUSION The SCN1A, SCN3A, and SCN9A gene mutations might be a pathogenic cause of EFS+ in Southern Chinese Han population.
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Affiliation(s)
- Hongxia Ma
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, China; Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong Province, China; Department of Pediatrics, Affiliated Hospital of Guangdong Medical University, Zhanjiang, Guangdong Province, China
| | - Yuxiong Guo
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, China; Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong Province, China
| | - Zhihong Chen
- Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong Province, China
| | - Lingan Wang
- Department of Neurology and Rehabilitation, Guangdong Women and Children's Hospital, Guangzhou, Guangdong Province, China
| | - Zhihong Tang
- Department of Pediatrics, Dongguan City Maternal & Child Health Hospital, Dongguan, Guangdong Province, China
| | - Jingwen Zhang
- Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong Province, China
| | - Qinfei Miao
- Shantou University, Shantou, Guangdong Province, China
| | - Qiongxiang Zhai
- The Second School of Clinical Medicine, Southern Medical University, Guangzhou, Guangdong Province, China; Department of Pediatrics, Guangdong Provincial People's Hospital, Guangdong Academy of Medical Sciences, Guangzhou, Guangdong Province, China.
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30
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Vinkšel M, Writzl K, Maver A, Peterlin B. Improving diagnostics of rare genetic diseases with NGS approaches. J Community Genet 2021; 12:247-256. [PMID: 33452619 PMCID: PMC8141085 DOI: 10.1007/s12687-020-00500-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/08/2020] [Indexed: 01/08/2023] Open
Abstract
According to a rough estimate, one in fifteen people worldwide is affected by a rare disease. Rare diseases are therefore common in clinical practice; however, timely diagnosis of rare diseases is still challenging. Introduction of novel methods based on next-generation sequencing (NGS) technology offers a successful diagnosis of genetically heterogeneous disorders, even in case of unclear clinical diagnostic hypothesis. However, the application of novel technology differs among the centres and health systems significantly. Our goal is to discuss the impact of the implementation of NGS in the diagnosis of rare diseases and present advantages along with challenges of diagnostic approach. Systematic implementation of NGS in health systems can significantly improve the access of patients with rare diseases to diagnosis and reduce the dependence of national health systems for cross-border collaboration.
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Affiliation(s)
- Mateja Vinkšel
- Clinical Institute of Genomic Medicine, University medical Centre Ljubljana, Zaloška cesta 7, Ljubljana, Slovenia
| | - Karin Writzl
- Clinical Institute of Genomic Medicine, University medical Centre Ljubljana, Zaloška cesta 7, Ljubljana, Slovenia
| | - Aleš Maver
- Clinical Institute of Genomic Medicine, University medical Centre Ljubljana, Zaloška cesta 7, Ljubljana, Slovenia
| | - Borut Peterlin
- Clinical Institute of Genomic Medicine, University medical Centre Ljubljana, Zaloška cesta 7, Ljubljana, Slovenia.
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Ahmad SF, Ahmad KA, Ng YT. Neonatal Epileptic Encephalopathies. Semin Pediatr Neurol 2021; 37:100880. [PMID: 33892847 DOI: 10.1016/j.spen.2021.100880] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 02/07/2021] [Accepted: 02/20/2021] [Indexed: 11/26/2022]
Abstract
The majority of neonatal seizures are related to common diagnoses, including hypoxic-ischemic encephalopathy and intraventricular hemorrhage. While relatively uncommon, neonatal epileptic encephalopathies represent an important group of neonatal seizure disorders that require immediate diagnosis and intervention. In this review, we provide a summary of the benign and severe neonatal epilepsy syndromes. While benign epilepsy syndromes have favorable prognoses, rapid and accurate diagnosis may prevent an unnecessarily long course of antiseizure medications. The severe epilepsy syndromes may be related to a number of underlying genetic disorders and often carry a poor prognosis. Herein we review diagnostic and therapeutic strategies, and provide a set or algorithms for said purposes.
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Affiliation(s)
- Samiya Fatima Ahmad
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX; The Children's Hospital of San Antonio, San Antonio, TX.
| | - Kaashif Aqeeb Ahmad
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX; The Children's Hospital of San Antonio, San Antonio, TX; Pediatrix Medical Group of San Antonio, San Antonio, TX
| | - Yu-Tze Ng
- Department of Pediatrics, Baylor College of Medicine, San Antonio, TX; The Children's Hospital of San Antonio, San Antonio, TX
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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.
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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
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Ademuwagun IA, Rotimi SO, Syrbe S, Ajamma YU, Adebiyi E. Voltage Gated Sodium Channel Genes in Epilepsy: Mutations, Functional Studies, and Treatment Dimensions. Front Neurol 2021; 12:600050. [PMID: 33841294 PMCID: PMC8024648 DOI: 10.3389/fneur.2021.600050] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 03/01/2021] [Indexed: 12/19/2022] Open
Abstract
Genetic epilepsy occurs as a result of mutations in either a single gene or an interplay of different genes. These mutations have been detected in ion channel and non-ion channel genes. A noteworthy class of ion channel genes are the voltage gated sodium channels (VGSCs) that play key roles in the depolarization phase of action potentials in neurons. Of huge significance are SCN1A, SCN1B, SCN2A, SCN3A, and SCN8A genes that are highly expressed in the brain. Genomic studies have revealed inherited and de novo mutations in sodium channels that are linked to different forms of epilepsies. Due to the high frequency of sodium channel mutations in epilepsy, this review discusses the pathogenic mutations in the sodium channel genes that lead to epilepsy. In addition, it explores the functional studies on some known mutations and the clinical significance of VGSC mutations in the medical management of epilepsy. The understanding of these channel mutations may serve as a strong guide in making effective treatment decisions in patient management.
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Affiliation(s)
- Ibitayo Abigail Ademuwagun
- Covenant University Bioinformatics Research, Covenant University, Ota, Nigeria
- Department of Biochemistry, Covenant University, Ota, Nigeria
| | - Solomon Oladapo Rotimi
- Covenant University Bioinformatics Research, Covenant University, Ota, Nigeria
- Department of Biochemistry, Covenant University, Ota, Nigeria
| | - Steffen Syrbe
- Clinic for Pediatric and Adolescent Medicine, Heidelberg University, Heidelberg, Germany
| | | | - Ezekiel Adebiyi
- Covenant University Bioinformatics Research, Covenant University, Ota, Nigeria
- Department of Computer and Information Sciences, Covenant University, Ota, Nigeria
- Division of Applied Bioinformatics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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Abstract
The voltage-gated sodium channel α-subunit genes comprise a highly conserved gene family. Mutations of three of these genes, SCN1A, SCN2A and SCN8A, are responsible for a significant burden of neurological disease. Recent progress in identification and functional characterization of patient variants is generating new insights and novel approaches to therapy for these devastating disorders. Here we review the basic elements of sodium channel function that are used to characterize patient variants. We summarize a large body of work using global and conditional mouse mutants to characterize the in vivo roles of these channels. We provide an overview of the neurological disorders associated with mutations of the human genes and examples of the effects of patient mutations on channel function. Finally, we highlight therapeutic interventions that are emerging from new insights into mechanisms of sodium channelopathies.
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Hussain SA, Heesch J, Weng J, Rajaraman RR, Numis AL, Sankar R. Potential induction of epileptic spasms by nonselective voltage-gated sodium channel blockade: Interaction with etiology. Epilepsy Behav 2021; 115:107624. [PMID: 33341392 DOI: 10.1016/j.yebeh.2020.107624] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 10/28/2020] [Accepted: 11/05/2020] [Indexed: 10/22/2022]
Abstract
PURPOSE Epileptic spasms are often preceded by focal (or multifocal) seizures. Based on a series of case reports suggesting that carbamazepine and oxcarbazepine may induce epileptic spasms, we set out to rigorously evaluate the potential association between exposure to voltage-gated sodium channel blockade and latency to epileptic spasms. METHODS We identified 50 cases (children with focal seizures and evolution to epileptic spasms) and 50 controls (children with focal seizures without evolution to epileptic spasms). For each patient, we reviewed all sequential neurology encounters between onset of epilepsy and emergence of epileptic spasms. For each encounter we recorded seizure-frequency and all anti-seizure therapy exposures. Using multivariable Cox proportional hazards regression, we evaluated the association between voltage-gated sodium channel exposure (carbamazepine, oxcarbazepine, lacosamide, or phenytoin) and latency to epileptic spasms onset, with adjustment for etiology and seizure-frequency. RESULTS Latency to epileptic spasms onset was independently associated with exposure to sodium channel blockade (hazard ratio = 2.4; 95% CI 1.1-5.2; P = 0.03) and high-risk etiology (hazard ratio = 2.8; 95% CI 1.5-5.1; P = 0.001). With assessment for interaction between sodium channel blockade and etiology, we identified an estimated 7-fold increased risk of epileptic spasms with the combination of sodium channel blockade and high-risk etiology (hazard ratio = 7.0, 95% CI 2.5-19.8; P < 0.001). CONCLUSION This study suggests that voltage-gated sodium channel blockade may induce epileptic spasms among children at risk on the basis of etiology. Further study is warranted to replicate these findings, ascertain possible drug- and dose-specific risks, and identify potential mechanisms of harm.
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Affiliation(s)
- Shaun A Hussain
- Division of Pediatric Neurology, David Geffen School of Medicine and UCLA Mattel Children's Hospital, Los Angeles, CA, United States.
| | - Jaeden Heesch
- Division of Pediatric Neurology, David Geffen School of Medicine and UCLA Mattel Children's Hospital, Los Angeles, CA, United States
| | - Julius Weng
- Division of Pediatric Neurology, David Geffen School of Medicine and UCLA Mattel Children's Hospital, Los Angeles, CA, United States
| | - Rajsekar R Rajaraman
- Division of Pediatric Neurology, David Geffen School of Medicine and UCLA Mattel Children's Hospital, Los Angeles, CA, United States
| | - Adam L Numis
- Departments of Neurology and Pediatrics, UCSF Benioff Children's Hospital, San Francisco, CA, United States
| | - Raman Sankar
- Division of Pediatric Neurology, David Geffen School of Medicine and UCLA Mattel Children's Hospital, Los Angeles, CA, United States
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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.
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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
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Hull JM, O’Malley HA, Chen C, Yuan Y, Denomme N, Bouza AA, Anumonwo C, Lopez‐Santiago LF, Isom LL. Excitatory and inhibitory neuron defects in a mouse model of Scn1b-linked EIEE52. Ann Clin Transl Neurol 2020; 7:2137-2149. [PMID: 32979291 PMCID: PMC7664274 DOI: 10.1002/acn3.51205] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/25/2020] [Accepted: 08/27/2020] [Indexed: 01/24/2023] Open
Abstract
OBJECTIVE Human variants in voltage-gated sodium channel (VGSC) α and β subunit genes are linked to developmental and epileptic encephalopathies (DEEs). Inherited, biallelic, loss-of-function variants in SCN1B, encoding the β1/β1B subunits, are linked to early infantile DEE (EIEE52). De novo, monoallelic variants in SCN1A (Nav1.1), SCN2A (Nav1.2), SCN3A (Nav1.3), and SCN8A (Nav1.6) are also linked to DEEs. While these VGSC-linked DEEs have similar presentations, they have diverse mechanisms of altered neuronal excitability. Mouse models have suggested that Scn2a-, Scn3a-, and Scn8a-linked DEE variants are, in general, gain of function, resulting in increased persistent or resurgent sodium current (INa ) and pyramidal neuron hyperexcitability. In contrast, Scn1a-linked DEE variants, in general, are loss-of-function, resulting in decreased INa and hypoexcitability of fast-spiking interneurons. VGSC β1 subunits associate with Nav1.1, Nav1.2, Nav1.3, and Nav1.6 and are expressed throughout the brain, raising the possibility that insults to both pyramidal and interneuron excitability may drive EIEE52 pathophysiology. METHODS We investigated excitability defects in pyramidal and parvalbumin-positive (PV +) interneurons in the Scn1b-/- model of EIEE52. We also used Scn1bFL/FL mice to delete Scn1b in specific neuronal populations. RESULTS Scn1b-/- cortical PV + interneurons were hypoexcitable, with reduced INa density. Scn1b-/- cortical pyramidal neurons had population-specific changes in excitability and impaired INa density. Scn1b deletion in PV + neurons resulted in 100% lethality, whereas deletion in Emx1 + or Camk2a + neurons did not affect survival. INTERPRETATION This work suggests that SCN1B-linked DEE variants impact both excitatory and inhibitory neurons, leading to the increased severity of EIEE52 relative to other DEEs.
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Affiliation(s)
- Jacob M. Hull
- Neuroscience Graduate ProgramUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | | | - Chunling Chen
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Yukun Yuan
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Nicholas Denomme
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Alexandra A. Bouza
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | - Charles Anumonwo
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
| | | | - Lori L. Isom
- Neuroscience Graduate ProgramUniversity of Michigan Medical SchoolAnn ArborMI48109USA
- Department of PharmacologyUniversity of Michigan Medical SchoolAnn ArborMI48109USA
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Encinas AC, Watkins JC, Longoria IA, Johnson JP, Hammer MF. Variable patterns of mutation density among NaV1.1, NaV1.2 and NaV1.6 point to channel-specific functional differences associated with childhood epilepsy. PLoS One 2020; 15:e0238121. [PMID: 32845893 PMCID: PMC7449494 DOI: 10.1371/journal.pone.0238121] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Accepted: 08/10/2020] [Indexed: 11/28/2022] Open
Abstract
Variants implicated in childhood epilepsy have been identified in all four voltage-gated sodium channels that initiate action potentials in the central nervous system. Previous research has focused on the functional effects of particular variants within the most studied of these channels (NaV1.1, NaV1.2 and NaV1.6); however, there have been few comparative studies across channels to infer the impact of mutations in patients with epilepsy. Here we compare patterns of variation in patient and public databases to test the hypothesis that regions of known functional significance within voltage-gated sodium (NaV) channels have an increased burden of deleterious variants. We assessed mutational burden in different regions of the Nav channels by (1) performing Fisher exact tests on odds ratios to infer excess variants in domains, segments, and loops of each channel in patient databases versus public “control” databases, and (2) comparing the cumulative distribution of variant sites along DNA sequences of each gene in patient and public databases (i.e., independent of protein structure). Patient variant density was concordant among channels in regions known to play a role in channel function, with statistically significant higher patient variant density in S4-S6 and DIII-DIV and an excess of public variants in SI-S3, DI-DII, DII-DIII. On the other hand, channel-specific patterns of patient burden were found in the NaV1.6 inactivation gate and NaV1.1 S5-S6 linkers, while NaV1.2 and NaV1.6 S4-S5 linkers and S5 segments shared patient variant patterns that contrasted with those in NaV1.1. These different patterns may reflect different roles played by the NaV1.6 inactivation gate in action potential propagation, and by NaV1.1 S5-S6 linkers in loss of function and haploinsufficiency. Interestingly, NaV1.2 and NaV1.6 both lack amino acid substitutions over significantly long stretches in both the patient and public databases suggesting that new mutations in these regions may cause embryonic lethality or a non-epileptic disease phenotype.
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Affiliation(s)
- Alejandra C. Encinas
- Graduate Program in Genetics, University of Arizona, Tucson, Arizona, United States of America
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | - Iris Arenas Longoria
- Department of Mathematics, University of Arizona, Tucson, Arizona, United States of America
| | | | - Michael F. Hammer
- Department of Neurology, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
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Menezes LFS, Sabiá Júnior EF, Tibery DV, Carneiro LDA, Schwartz EF. Epilepsy-Related Voltage-Gated Sodium Channelopathies: A Review. Front Pharmacol 2020; 11:1276. [PMID: 33013363 PMCID: PMC7461817 DOI: 10.3389/fphar.2020.01276] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/31/2020] [Indexed: 12/29/2022] Open
Abstract
Epilepsy is a disease characterized by abnormal brain activity and a predisposition to generate epileptic seizures, leading to neurobiological, cognitive, psychological, social, and economic impacts for the patient. There are several known causes for epilepsy; one of them is the malfunction of ion channels, resulting from mutations. Voltage-gated sodium channels (NaV) play an essential role in the generation and propagation of action potential, and malfunction caused by mutations can induce irregular neuronal activity. That said, several genetic variations in NaV channels have been described and associated with epilepsy. These mutations can affect channel kinetics, modifying channel activation, inactivation, recovery from inactivation, and/or the current window. Among the NaV subtypes related to epilepsy, NaV1.1 is doubtless the most relevant, with more than 1500 mutations described. Truncation and missense mutations are the most observed alterations. In addition, several studies have already related mutated NaV channels with the electrophysiological functioning of the channel, aiming to correlate with the epilepsy phenotype. The present review provides an overview of studies on epilepsy-associated mutated human NaV1.1, NaV1.2, NaV1.3, NaV1.6, and NaV1.7.
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Affiliation(s)
- Luis Felipe Santos Menezes
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Elias Ferreira Sabiá Júnior
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Diogo Vieira Tibery
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Lilian Dos Anjos Carneiro
- Faculdade de Medicina, Centro Universitário Euro Americano, Brasília, Brazil.,Faculdade de Medicina, Centro Universitário do Planalto Central, Brasília, Brazil
| | - Elisabeth Ferroni Schwartz
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
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40
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Systematic identification of genetic systems associated with phenotypes in patients with rare genomic copy number variations. Hum Genet 2020; 140:457-475. [PMID: 32778951 DOI: 10.1007/s00439-020-02214-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 07/30/2020] [Indexed: 01/02/2023]
Abstract
Copy number variation (CNV) related disorders tend to show complex phenotypic profiles that do not match known diseases. This makes it difficult to ascertain their underlying molecular basis. A potential solution is to compare the affected genomic regions for multiple patients that share a pathological phenotype, looking for commonalities. Here, we present a novel approach to associate phenotypes with functional systems, in terms of GO categories and KEGG and Reactome pathways, based on patient data. The approach uses genomic and phenomic data from the same patients, finding shared genomic regions between patients with similar phenotypes. These regions are mapped to genes to find associated functional systems. We applied the approach to analyse patients in the DECIPHER database with de novo CNVs, finding functional systems associated with most phenotypes, often due to mutations affecting related genes in the same genomic region. Manual inspection of the ten top-scoring phenotypes found multiple FunSys connections supported by the previous studies for seven of them. The workflow also produces reports focussed on the genes and FunSys connected to the different phenotypes, alongside patient-specific reports, which give details of the associated genes and FunSys for each individual in the cohort. These can be run in "confidential" mode, preserving patient confidentiality. The workflow presented here can be used to associate phenotypes with functional systems using data at the level of a whole cohort of patients, identifying important connections that could not be found when considering them individually. The full workflow is available for download, enabling it to be run on any patient cohort for which phenotypic and CNV data are available.
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Zaman T, Helbig KL, Clatot J, Thompson CH, Kang SK, Stouffs K, Jansen AE, Verstraete L, Jacquinet A, Parrini E, Guerrini R, Fujiwara Y, Miyatake S, Ben‐Zeev B, Bassan H, Reish O, Marom D, Hauser N, Vu T, Ackermann S, Spencer CE, Lippa N, Srinivasan S, Charzewska A, Hoffman‐Zacharska D, Fitzpatrick D, Harrison V, Vasudevan P, Joss S, Pilz DT, Fawcett KA, Helbig I, Matsumoto N, Kearney JA, Fry AE, Goldberg EM. SCN3A
‐Related Neurodevelopmental Disorder: A Spectrum of Epilepsy and Brain Malformation. Ann Neurol 2020; 88:348-362. [DOI: 10.1002/ana.25809] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 05/05/2020] [Accepted: 05/25/2020] [Indexed: 12/19/2022]
Affiliation(s)
- Tariq Zaman
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Katherine L. Helbig
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Jérôme Clatot
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Christopher H. Thompson
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Seok Kyu Kang
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Katrien Stouffs
- Center for Medical Genetics/Research Center for Reproduction and Genetics University Hospital Brussels, Free University of Brussels Brussels Belgium
| | - Anna E. Jansen
- Pediatric Neurology Unit, Department of Pediatrics University Hospital Brussels Brussels Belgium
- Neurogenetics Research Group Free University of Brussels Brussels Belgium
| | | | - Adeline Jacquinet
- Human Genetics Service Sart Tilman University Hospital Center Liege Belgium
| | - Elena Parrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Department of Neuroscience A. Meyer Children's Hospital, University of Florence Florence Italy
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics, and Neurobiology Unit and Laboratories, Department of Neuroscience A. Meyer Children's Hospital, University of Florence Florence Italy
| | - Yuh Fujiwara
- Department of Pediatrics Yokohama City University Medical Center Yokohama Japan
| | - Satoko Miyatake
- Department of Human Genetics Yokohama City University Graduate School of Medicine Yokohama Japan
| | - Bruria Ben‐Zeev
- Pediatric Neurology Unit Edmond and Lili Safra Children's Hospital, Haim Sheba Medical Center Ramat Gan Israel
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
| | - Haim Bassan
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Pediatric Neurology & Development Center Shamir Medical Center (Assaf Harofe) Zerifin Israel
| | - Orit Reish
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Genetics Institute Shamir Medical Center (Assaf Harofe) Zerifin Zerifin Israel
| | - Daphna Marom
- Sackler School of Medicine Tel Aviv University Tel Aviv Israel
- Genetics Institute Shamir Medical Center (Assaf Harofe) Zerifin Zerifin Israel
| | - Natalie Hauser
- Inova Translational Medicine Institute Inova Health System Fairfax Virginia USA
| | - Thuy‐Anh Vu
- Department of Pediatric Neurology Children's National Medical Center, Washington, District of Columbia, and Pediatric Specialists of Virginia Fairfax Virginia USA
| | - Sally Ackermann
- Division of Paediatric Neurology, Department of Paediatrics and Child Health Red Cross War Memorial Children's Hospital, University of Cape Town Cape Town South Africa
| | - Careni E. Spencer
- Division of Human Genetics, Department of Medicine University of Cape Town, South Africa and Groote Schuur Hospital Cape Town South Africa
| | - Natalie Lippa
- Institute for Genomic Medicine Columbia University Medical Center New York New York USA
| | - Shraddha Srinivasan
- Department of Neurology Columbia University Medical Center New York New York USA
| | | | | | - David Fitzpatrick
- Medical Research Council Human Genetics Unit Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh Edinburgh United Kingdom
| | - Victoria Harrison
- Wessex Clinical Genetics Service Princess Anne Hospital Southampton United Kingdom
| | - Pradeep Vasudevan
- Department of Clinical Genetics University Hospitals Leicester National Health Service Trust Leicester United Kingdom
| | - Shelagh Joss
- West of Scotland Clinical Genetics Service Queen Elizabeth University Hospital Glasgow United Kingdom
| | - Daniela T. Pilz
- West of Scotland Clinical Genetics Service Queen Elizabeth University Hospital Glasgow United Kingdom
- Division of Cancer and Genetics School of Medicine, Cardiff University Cardiff United Kingdom
| | - Katherine A. Fawcett
- Medical Research Council (MRC) Computational Genomics Analysis and Training Programme, MRC Centre for Computational Biology, MRC Weatherall Institute of Molecular Medicine, John Radcliffe Hospital Oxford United Kingdom
| | - Ingo Helbig
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Department of Neurology, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
- Department of Biomedical and Health Informatics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
| | - Naomichi Matsumoto
- Department of Human Genetics Yokohama City University Graduate School of Medicine Yokohama Japan
| | - Jennifer A. Kearney
- Department of Pharmacology Northwestern University Feinberg School of Medicine Chicago Illinois USA
| | - Andrew E. Fry
- Division of Cancer and Genetics School of Medicine, Cardiff University Cardiff United Kingdom
- Institute of Medical Genetics University Hospital of Wales Cardiff United Kingdom
| | - Ethan M. Goldberg
- Division of Neurology, Department of Pediatrics Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Epilepsy NeuroGenetics Initiative Children's Hospital of Philadelphia Philadelphia Pennsylvania USA
- Department of Neurology, Perelman School of Medicine University of Pennsylvania Philadelphia Pennsylvania USA
- Department of Neuroscience Perelman School of Medicine, University of Pennsylvania Philadelphia Pennsylvania USA
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42
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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.
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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
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43
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Cardoso FC. Multi-targeting sodium and calcium channels using venom peptides for the treatment of complex ion channels-related diseases. Biochem Pharmacol 2020; 181:114107. [PMID: 32579958 DOI: 10.1016/j.bcp.2020.114107] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/13/2020] [Accepted: 06/17/2020] [Indexed: 02/08/2023]
Abstract
Venom peptides are amongst the most exquisite group of bioactive molecules able to alter the normal physiology of organisms. These bioactive peptides penetrate tissues and blood vessels to encounter a number of receptors and ion channels to which they bind with high affinity and execute modulatory activities. Arachnid is the most diverse class of venomous animals often rich in peptides modulating voltage-gated sodium (NaV), calcium (CaV), and potassium (KV) channels. Spider venoms, in particular, contain potent and selective peptides targeting these channels, with a few displaying interesting multi-target properties for NaV and CaV channels underlying disease mechanisms such as in neuropathic pain, motor neuron disease and cancer. The elucidation of the pharmacology and structure-function properties of these venom peptides are invaluable for the development of effective drugs targeting NaV and CaV channels. This perspective discusses spider venom peptides displaying multi-target properties to modulate NaV and CaV channels in regard to their pharmacological features, structure-function relationships and potential to become the next generation of effective drugs to treat neurological disorders and other multi-ion channels related diseases.
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Affiliation(s)
- Fernanda C Cardoso
- Institute for Molecular Bioscience, The University of Queensland, 306 Carmody Rd., St Lucia, QLD AU 4072, Australia
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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.
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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
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Noebels JL. Predicting the impact of sodium channel mutations in human brain disease. Epilepsia 2020; 60 Suppl 3:S8-S16. [PMID: 31904123 PMCID: PMC6953257 DOI: 10.1111/epi.14724] [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: 02/05/2019] [Revised: 03/15/2019] [Accepted: 03/18/2019] [Indexed: 12/21/2022]
Abstract
Genetic alteration of the sodium channel provides a remarkable opportunity to understand how epilepsy and its comorbidities arise from a molecular disease of excitable membranes, and a chance to create a better future for children with epileptic encephalopathy. In a single cell, the channel reliably acts as a voltage-sensitive switch, enabling axon impulse firing, whereas at a network level, it becomes a variable rheostat for regulating dynamic patterns of neuronal oscillations, including those underlying cognitive development, seizures, and even premature lethality. Despite steady progress linking genetic variation of the channels with distinctive clinical syndromes, our understanding of the intervening biologic complexity underlying each of them is only just beginning. More research on the functional contribution of individual channel subunits to specific brain networks and cellular plasticity in the developing brain is needed before we can reliably advance from precision diagnosis to precision treatment of inherited sodium channel disorders.
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Affiliation(s)
- Jeffrey L Noebels
- Blue Bird Circle Developmental Neurogenetics Laboratory, Departments of Neurology, Neuroscience, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas
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46
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Matthews E, Balestrini S, Sisodiya SM, Hanna MG. Muscle and brain sodium channelopathies: genetic causes, clinical phenotypes, and management approaches. THE LANCET CHILD & ADOLESCENT HEALTH 2020; 4:536-547. [PMID: 32142633 DOI: 10.1016/s2352-4642(19)30425-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/29/2019] [Accepted: 12/12/2019] [Indexed: 01/26/2023]
Abstract
Voltage-gated sodium channels are essential for excitability of skeletal muscle fibres and neurons. An increasing number of disabling or fatal paediatric neurological disorders linked to mutations of voltage-gated sodium channel genes are recognised. Muscle phenotypes include episodic paralysis, myotonia, neonatal hypotonia, respiratory compromise, laryngospasm or stridor, congenital myasthenia, and myopathy. Evidence suggests a possible link between sodium channel dysfunction and sudden infant death. Increasingly recognised phenotypes of brain sodium channelopathies include several epilepsy disorders and complex encephalopathies. Together, these early-onset muscle and brain phenotypes have a substantial morbidity and a considerable mortality. Important advances in understanding the pathophysiological mechanisms underlying these channelopathies have helped to identify effective targeted therapies. The availability of effective treatments underlines the importance of increasing clinical awareness and the need to achieve a precise genetic diagnosis. In this Review, we describe the expanded range of phenotypes of muscle and brain sodium channelopathies and the underlying knowledge regarding mechanisms of sodium channel dysfunction. We also outline a diagnostic approach and review the available treatment options.
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Affiliation(s)
- Emma Matthews
- Department of Neuromuscular Diseases, Medical Research Council Centre for Neuromuscular Diseases, University College London Queen Square Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK.
| | - Simona Balestrini
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK; Chalfont Centre for Epilepsy, Buckinghamshire, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK
| | - Sanjay M Sisodiya
- Department of Clinical and Experimental Epilepsy, University College London Queen Square Institute of Neurology, London, UK; Chalfont Centre for Epilepsy, Buckinghamshire, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK
| | - Michael G Hanna
- Department of Neuromuscular Diseases, Medical Research Council Centre for Neuromuscular Diseases, University College London Queen Square Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, University College London Hospitals National Health Service Foundation Trust, London, UK
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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.
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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
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Cárdenas-Rodríguez N, Carmona-Aparicio L, Pérez-Lozano DL, Ortega-Cuellar D, Gómez-Manzo S, Ignacio-Mejía I. Genetic variations associated with pharmacoresistant epilepsy (Review). Mol Med Rep 2020; 21:1685-1701. [PMID: 32319641 PMCID: PMC7057824 DOI: 10.3892/mmr.2020.10999] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 01/16/2020] [Indexed: 12/13/2022] Open
Abstract
Epilepsy is a common, serious neurological disorder worldwide. Although this disease can be successfully treated in most cases, not all patients respond favorably to medical treatments, which can lead to pharmacoresistant epilepsy. Drug-resistant epilepsy can be caused by a number of mechanisms that may involve environmental and genetic factors, as well as disease- and drug-related factors. In recent years, numerous studies have demonstrated that genetic variation is involved in the drug resistance of epilepsy, especially genetic variations found in drug resistance-related genes, including the voltage-dependent sodium and potassium channels genes, and the metabolizer of endogenous and xenobiotic substances genes. The present review aimed to highlight the genetic variants that are involved in the regulation of drug resistance in epilepsy; a comprehensive understanding of the role of genetic variation in drug resistance will help us develop improved strategies to regulate drug resistance efficiently and determine the pathophysiological processes that underlie this common human neurological disease.
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Affiliation(s)
- Noemí Cárdenas-Rodríguez
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Liliana Carmona-Aparicio
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Diana L Pérez-Lozano
- Laboratory of Neuroscience, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Daniel Ortega-Cuellar
- Laboratory of Experimental Nutrition, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Saúl Gómez-Manzo
- Laboratory of Genetic Biochemistry, National Institute of Pediatrics, Ministry of Health, Coyoacán, Mexico City 04530, Mexico
| | - Iván Ignacio-Mejía
- Laboratory of Translational Medicine, Military School of Health Graduates, Lomas de Sotelo, Militar, Mexico City 11200, Mexico
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Inuzuka LM, Macedo-Souza LI, Della-Ripa B, Cabral KSS, Monteiro F, Kitajima JP, de Souza Godoy LF, de Souza Delgado D, Kok F, Garzon E. Neurodevelopmental disorder associated with de novo SCN3A pathogenic variants: two new cases and review of the literature. Brain Dev 2020; 42:211-216. [PMID: 31677917 DOI: 10.1016/j.braindev.2019.09.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Revised: 08/28/2019] [Accepted: 09/10/2019] [Indexed: 10/25/2022]
Abstract
SCN3A was recently recognized as a gene associated with neurodevelopmental disorder and epilepsy. We present two additional patients with a novel de novo SCN3A pathogenic variant, and a review of all published cases of de novo variants. In one of our patients brain magnetic resonance imaging (MRI) disclosed a severe polymicrogyria and in the other it was normal. The clinical phenotype was characterized by a severe developmental delay and refractory epilepsy in the patient with polymicrogyria and intellectual disability with autistic features and pharmacoresponsive epilepsy in the subject with normal MRI. Polymicrogyria, a disorder of progenitor cells proliferation and migration, is an unanticipated finding for an ion channel dysfunction.
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Affiliation(s)
- Luciana Midori Inuzuka
- Epilepsy Clinic, Hospital Sírio-Libanês, São Paulo, Brazil; Department of Neurology, University of São Paulo School of Medicine, Brazil.
| | | | - Bruno Della-Ripa
- Department of Neurology, University of São Paulo School of Medicine, Brazil.
| | - Katiane S S Cabral
- Department of Neurology, University of São Paulo School of Medicine, Brazil.
| | | | | | | | | | - Fernando Kok
- Mendelics Genomic Analysis, São Paulo, Brazil; Department of Neurology, University of São Paulo School of Medicine, Brazil.
| | - Eliana Garzon
- Epilepsy Clinic, Hospital Sírio-Libanês, São Paulo, Brazil; Department of Neurology, University of São Paulo School of Medicine, Brazil.
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50
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Smith RS, Walsh CA. Ion Channel Functions in Early Brain Development. Trends Neurosci 2020; 43:103-114. [PMID: 31959360 PMCID: PMC7092371 DOI: 10.1016/j.tins.2019.12.004] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/08/2019] [Accepted: 12/10/2019] [Indexed: 12/12/2022]
Abstract
During prenatal brain development, ion channels are ubiquitous across several cell types, including progenitor cells and migrating neurons but their function has not been clear. In the past, ion channel dysfunction has been primarily studied in the context of postnatal, differentiated neurons that fire action potentials - notably ion channels mutated in the epilepsies - yet data now support a surprising role in prenatal human brain disorders as well. Modern gene discovery approaches have identified defective ion channels in individuals with cerebral cortex malformations, which reflect abnormalities in early-to-middle stages of embryonic development (prior to ubiquitous action potentials). These human genetics studies and recent in utero animal modeling work suggest that precise control of ionic flux (calcium, sodium, and potassium) contributes to in utero developmental processes such as neural proliferation, migration, and differentiation.
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Affiliation(s)
- Richard S Smith
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, and Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, and Howard Hughes Medical Institute, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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