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Graziano B, Wang L, White OR, Kaplan DH, Fernandez-Abascal J, Bianchi L. Glial KCNQ K + channels control neuronal output by regulating GABA release from glia in C. elegans. Neuron 2024; 112:1832-1847.e7. [PMID: 38460523 PMCID: PMC11156561 DOI: 10.1016/j.neuron.2024.02.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 01/22/2024] [Accepted: 02/16/2024] [Indexed: 03/11/2024]
Abstract
KCNQs are voltage-gated K+ channels that control neuronal excitability and are mutated in epilepsy and autism spectrum disorder (ASD). KCNQs have been extensively studied in neurons, but their function in glia is unknown. Using voltage, calcium, and GABA imaging, optogenetics, and behavioral assays, we show here for the first time in Caenorhabditis elegans (C. elegans) that glial KCNQ channels control neuronal excitability by mediating GABA release from glia via regulation of the function of L-type voltage-gated Ca2+ channels. Further, we show that human KCNQ channels have the same role when expressed in nematode glia, underscoring conservation of function across species. Finally, we show that pathogenic loss-of-function and gain-of-function human KCNQ2 mutations alter glia-to-neuron GABA signaling in distinct ways and that the KCNQ channel opener retigabine exerts rescuing effects. This work identifies glial KCNQ channels as key regulators of neuronal excitability via control of GABA release from glia.
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Affiliation(s)
- Bianca Graziano
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Lei Wang
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Olivia R White
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Daryn H Kaplan
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Jesus Fernandez-Abascal
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Laura Bianchi
- Department Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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Qunies AM, Spitznagel BD, Du Y, Peprah PK, Mohamed YK, Weaver CD, Emmitte KA. Structure-Activity Relationship Studies in a Series of Xanthine Inhibitors of SLACK Potassium Channels. Molecules 2024; 29:2437. [PMID: 38893312 PMCID: PMC11173529 DOI: 10.3390/molecules29112437] [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: 04/30/2024] [Revised: 05/17/2024] [Accepted: 05/20/2024] [Indexed: 06/21/2024] Open
Abstract
Gain-of-function mutations in the KCNT1 gene, which encodes the sodium-activated potassium channel known as SLACK, are associated with the rare but devastating developmental and epileptic encephalopathy known as epilepsy of infancy with migrating focal seizures (EIMFS). The design of small molecule inhibitors of SLACK channels represents a potential therapeutic approach to the treatment of EIMFS, other childhood epilepsies, and developmental disorders. Herein, we describe a hit optimization effort centered on a xanthine SLACK inhibitor (8) discovered via a high-throughput screen. Across three distinct regions of the chemotype, we synthesized 58 new analogs and tested each one in a whole-cell automated patch-clamp assay to develop structure-activity relationships for inhibition of SLACK channels. We further evaluated selected analogs for their selectivity versus a variety of other ion channels and for their activity versus clinically relevant SLACK mutants. Selectivity within the series was quite good, including versus hERG. Analog 80 (VU0948578) was a potent inhibitor of WT, A934T, and G288S SLACK, with IC50 values between 0.59 and 0.71 µM across these variants. VU0948578 represents a useful in vitro tool compound from a chemotype that is distinct from previously reported small molecule inhibitors of SLACK channels.
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Affiliation(s)
- Alshaima’a M. Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | | | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Paul K. Peprah
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
- School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Yasmeen K. Mohamed
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
- Vanderbilt Institute for Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
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3
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Qunies AM, Spitznagel BD, Du Y, David Weaver C, Emmitte KA. Design, synthesis, and biological evaluation of a novel series of 1,2,4-oxadiazole inhibitors of SLACK potassium channels: Identification of in vitro tool VU0935685. Bioorg Med Chem 2023; 95:117487. [PMID: 37812884 PMCID: PMC10842602 DOI: 10.1016/j.bmc.2023.117487] [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: 07/05/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/11/2023]
Abstract
Malignant migrating partial seizure of infancy (MMPSI) is a devastating and pharmacoresistant form of infantile epilepsy. MMPSI has been linked to multiple gain-of-function (GOF) mutations in the KCNT1 gene, which encodes for a potassium channel often referred to as SLACK. SLACK channels are sodium-activated potassium channels distributed throughout the central nervous system (CNS) and the periphery. The investigation described here aims to discover SLACK channel inhibitor tool compounds and profile their pharmacokinetic and pharmacodynamic properties. A SLACK channel inhibitor VU0531245 (VU245) was identified via a high-throughput screen (HTS) campaign. Structure-activity relationship (SAR) studies were conducted in five distinct regions of the hit VU245. VU245 analogs were evaluated for their ability to affect SLACK channel activity using a thallium flux assay in HEK-293 cells stably expressing wild-type (WT) human SLACK. Selected analogs were tested for metabolic stability in mouse liver microsomes and plasma-protein binding in mouse plasma. The same set of analogs was tested via thallium flux for activity versus human A934T SLACK and other structurally related potassium channels, including SLICK and Maxi-K. In addition, potencies for selected VU245 analogs were obtained using whole-cell electrophysiology (EP) assays in CHO cells stably expressing WT human SLACK through an automated patch clamp system. Results revealed that this scaffold tolerates structural changes in some regions, with some analogs demonstrating improved SLACK inhibitory activity, good selectivity against the other channels tested, and modest improvements in metabolic clearance. Analog VU0935685 represents a new, structurally distinct small-molecule inhibitor of SLACK channels that can serve as an in vitro tool for studying this target.
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Affiliation(s)
- Alshaima'a M Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA; School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | | | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kyle A Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA.
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Hou B, Santaniello S, Tzingounis AV. KCNQ2 channels regulate the population activity of neonatal GABAergic neurons ex vivo. Front Neurol 2023; 14:1207539. [PMID: 37409016 PMCID: PMC10318362 DOI: 10.3389/fneur.2023.1207539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 05/18/2023] [Indexed: 07/07/2023] Open
Abstract
Over the last decade KCNQ2 channels have arisen as fundamental and indispensable regulators of neonatal brain excitability, with KCNQ2 loss-of-function pathogenic variants being increasingly identified in patients with developmental and epileptic encephalopathy. However, the mechanisms by which KCNQ2 loss-of-function variants lead to network dysfunction are not fully known. An important remaining knowledge gap is whether loss of KCNQ2 function alters GABAergic interneuron activity early in development. To address this question, we applied mesoscale calcium imaging ex vivo in postnatal day 4-7 mice lacking KCNQ2 channels in interneurons (Vgat-ires-cre;Kcnq2f/f;GCamp5). In the presence of elevated extracellular potassium concentrations, ablation of KCNQ2 channels from GABAergic cells increased the interneuron population activity in the hippocampal formation and regions of the neocortex. We found that this increased population activity depends on fast synaptic transmission, with excitatory transmission promoting the activity and GABAergic transmission curtailing it. Together, our data show that loss of function of KCNQ2 channels from interneurons increases the network excitability of the immature GABAergic circuits, revealing a new function of KCNQ2 channels in interneuron physiology in the developing brain.
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Affiliation(s)
- Bowen Hou
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
| | - Sabato Santaniello
- Department of Biomedical Engineering and CT Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, United States
| | - Anastasios V. Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, United States
- Department of Biomedical Engineering and CT Institute for the Brain and Cognitive Sciences, University of Connecticut, Storrs, CT, United States
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Donnan AM, Schneider AL, Russ-Hall S, Churilov L, Scheffer IE. Rates of Status Epilepticus and Sudden Unexplained Death in Epilepsy in People With Genetic Developmental and Epileptic Encephalopathies. Neurology 2023; 100:e1712-e1722. [PMID: 36750385 PMCID: PMC10115508 DOI: 10.1212/wnl.0000000000207080] [Citation(s) in RCA: 20] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Accepted: 01/05/2023] [Indexed: 02/09/2023] Open
Abstract
BACKGROUND AND OBJECTIVES The genetic developmental and epileptic encephalopathies (DEEs) comprise a large group of severe epilepsy syndromes, with a wide phenotypic spectrum. Currently, the rates of convulsive status epilepticus (CSE), nonconvulsive status epilepticus (NCSE), and sudden unexplained death in epilepsy (SUDEP) in these diseases are not well understood. We aimed to describe the proportions of patients with frequently observed genetic DEEs who developed CSE, NCSE, mortality, and SUDEP. Understanding the risks of these serious presentations in each genetic DEE will enable earlier diagnosis and appropriate management. METHODS In this retrospective analysis of patients with a genetic DEE, we estimated the proportions with CSE, NCSE, and SUDEP and the overall and SUDEP-specific mortality rates for each genetic diagnosis. We included patients with a pathogenic variant in the genes SCN1A, SCN2A, SCN8A, SYNGAP1, NEXMIF, CHD2, PCDH19, STXBP1, GRIN2A, KCNT1, and KCNQ2 and with Angelman syndrome (AS). RESULTS The cohort comprised 510 individuals with a genetic DEE, in whom we observed CSE in 47% and NCSE in 19%. The highest proportion of CSE occurred in patients with SCN1A-associated DEEs, including 181/203 (89%; 95% CI 84-93) patients with Dravet syndrome and 8/15 (53%; 95% CI 27-79) non-Dravet SCN1A-DEEs. CSE was also notable in patients with pathogenic variants in KCNT1 (6/10; 60%; 95% CI 26-88) and SCN2A (8/15; 53%; 95% CI 27-79). NCSE was common in patients with non-Dravet SCN1A-DEEs (8/15; 53%; 95% CI 27-79) and was notable in patients with CHD2-DEEs (6/14; 43%; 95% CI 18-71) and AS (6/19; 32%; 95% CI 13-57). There were 42/510 (8%) deaths among the cohort, producing a mortality rate of 6.1 per 1,000 person-years (95% CI 4.4-8.3). Cases of SUDEP accounted for 19/42 (48%) deaths. Four genes were associated with SUDEP: SCN1A, SCN2A, SCN8A, and STXBP1. The estimated SUDEP rate was 2.8 per 1,000 person-years (95% CI 1.6-4.3). DISCUSSION We showed that proportions of patients with CSE, NCSE, and SUDEP differ for commonly encountered genetic DEEs. The estimates for each genetic DEE studied will inform early diagnosis and management of status epilepticus and SUDEP and inform disease-specific counseling for patients and families in this high-risk group of conditions.
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Affiliation(s)
- Alice M Donnan
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Amy L Schneider
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Sophie Russ-Hall
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Leonid Churilov
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia
| | - Ingrid E Scheffer
- From the Epilepsy Research Centre (A.M.D., A.L.S., S.R.-H., I.E.S.), Department of Medicine, The University of Melbourne, Austin Health; Melbourne Medical School (L.C.), Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville; The Florey Institute of Neurosciences and Mental Health (L.C., I.E.S.), Melbourne; and Department of Paediatrics (I.E.S.), The University of Melbourne, Royal Children's Hospital, and Murdoch Children's Research Institute, Victoria, Australia.
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Perinelli MG, Riva A, Amadori E, Follo R, Striano P. Learnings in developmental and epileptic encephalopathies: what do we know? Expert Rev Neurother 2023; 23:45-57. [PMID: 36726225 DOI: 10.1080/14737175.2023.2176221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
INTRODUCTION Developmental and Epileptic Encephalopathies (DEEs) encompass a group of neurological disorders caused by either abnormal neuronal development and white matter maturation or even by weak synaptic plasticity. Hitherto, patients commonly have epileptic seizures featuring cognitive dysfunction, such as neurosensory disorders, difficulties in learning, behavioral disturbances, or speech delay. AREAS COVERED This paper provides a comprehensive review of the current knowledge of DEEs and cognition. Medline/Pubmed database was screened for in-English articles published between 1967-2022 dealing with the topic of DEEs and cognitive development. Two authors independently screened the title and abstract of each record and reviewed the selected articles. Reviews, randomized clinical trials, and case reports were selected. EXPERT OPINION Scientific literature has never explicitly dealt with the early neuro-psychomotor rehabilitation and neuropsychological assessment of patients with DEEs. Targeted intervention and environmental stimuli can influence the maturation of neuronal circuits and shape changes in physical and mental development based on neuronal plasticity, particularly if applied in 'critical periods' liable to heightened sensitivity. Thus, 'early neurorehabilitation interventions' are worthy of being more and more applied to clinical practice to improve the quality of life and reduce the psychosocial burden on families and caregivers.
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Affiliation(s)
- Martina Giorgia Perinelli
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Antonella Riva
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Elisabetta Amadori
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | | | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy.,IRCCS Istituto Giannina Gaslini, Genoa, Italy
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Qunies AM, Mishra NM, Spitznagel BD, Du Y, Acuña VS, David Weaver C, Emmitte KA. Structure-activity relationship studies in a new series of 2-amino-N-phenylacetamide inhibitors of Slack potassium channels. Bioorg Med Chem Lett 2022; 76:129013. [PMID: 36184030 PMCID: PMC10230575 DOI: 10.1016/j.bmcl.2022.129013] [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: 07/14/2022] [Revised: 09/20/2022] [Accepted: 09/26/2022] [Indexed: 11/02/2022]
Abstract
In this Letter we describe structure-activity relationship (SAR) studies conducted in five distinct regions of a new 2-amino-N-phenylacetamides series of Slack potassium channel inhibitors exemplified by recently disclosed high-throughput screening (HTS) hit VU0606170 (4). New analogs were screened in a thallium (Tl+) flux assay in HEK-293 cells stably expressing wild-type human (WT) Slack. Selected analogs were screened in Tl+ flux versus A934T Slack and other Slo family members Slick and Maxi-K and evaluated in whole-cell electrophysiology (EP) assays using an automated patch clamp system. Results revealed the series to have flat SAR with significant structural modifications resulting in a loss of Slack activity. More minor changes led to compounds with Slack activity and Slo family selectivity similar to the HTS hit.
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Affiliation(s)
- Alshaima'a M Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA; Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Nigam M Mishra
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | | | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Valerie S Acuña
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - C David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kyle A Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, TX, USA.
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Kim EH, Shin J, Lee BK. Neonatal seizures: diagnostic updates based on new definition and classification. Clin Exp Pediatr 2022; 65:387-397. [PMID: 35381171 PMCID: PMC9348949 DOI: 10.3345/cep.2021.01361] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/05/2021] [Indexed: 11/27/2022] Open
Abstract
Neonatal seizures are the most common neurological symptoms caused by various etiologies in the neonatal period, but their diagnosis and treatment are challenging because their pathophysiology and electroclinical manifestations differ from those of patients in older age groups. Many seizures present as electrographic-only events without clinical signs or as obscure clinical manifestations that are difficult to distinguish from other neonatal behaviors. Accordingly, a new definition and classification of neonatal seizures was recently proposed by the International League Against Epilepsy Task Force on neonatal seizures, highlighting the role of electroencephalography in diagnosing and treating neonatal seizures. Neonatal seizures are defined as electrographic events with sudden, paroxysmal, and abnormal alteration of activity and divided into electroclinical seizures and electrographic-only seizures according to their clinical signs, thus excluding clinical events without an electrographic correlation. Seizure types are described by their predominant clinical features and divided into motor (automatisms, clonic, epileptic spasms, myoclonic, tonic, and sequential), nonmotor (autonomic and behavioral arrest), and unclassified. Although many neonatal seizures are acute reactive events caused by hypoxic-ischemic encephalopathy or vascular insults, structural, genetic, or metabolic etiologies of neonatal-onset epilepsy should also be thoroughly evaluated to determine their appropriate management.
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Affiliation(s)
- Eun-Hee Kim
- Department of Pediatrics, Chungnam National University Sejong Hospital, Chungnam National University School of Medicine, Sejong, Korea
| | - Jeongmin Shin
- Department of Pediatrics, Chungnam National University Sejong Hospital, Chungnam National University School of Medicine, Sejong, Korea
| | - Byoung Kook Lee
- Department of Pediatrics, Chungnam National University Sejong Hospital, Chungnam National University School of Medicine, Sejong, Korea
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Shimada S, Ng BG, White AL, Nickander KK, Turgeon C, Liedtke KL, Lam CT, Font-Montgomery E, Lourenço CM, He M, Peck DS, Umaña LA, Uhles CL, Haynes D, Wheeler PG, Bamshad MJ, Nickerson DA, Cushing T, Gates R, Gomez-Ospina N, Byers HM, Scalco FB, Martinez NN, Sachdev R, Smith L, Poduri A, Malone S, Harris R, Scheffer IE, Rosenzweig SD, Adams DR, Gahl WA, Malicdan MCV, Raymond KM, Freeze HH, Wolfe LA. Clinical, biochemical and genetic characteristics of MOGS-CDG: a rare congenital disorder of glycosylation. J Med Genet 2022; 59:jmedgenet-2021-108177. [PMID: 35790351 PMCID: PMC9813274 DOI: 10.1136/jmedgenet-2021-108177] [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: 10/21/2021] [Accepted: 04/18/2022] [Indexed: 01/07/2023]
Abstract
PURPOSE To summarise the clinical, molecular and biochemical phenotype of mannosyl-oligosaccharide glucosidase-related congenital disorders of glycosylation (MOGS-CDG), which presents with variable clinical manifestations, and to analyse which clinical biochemical assay consistently supports diagnosis in individuals with bi-allelic variants in MOGS. METHODS Phenotypic characterisation was performed through an international and multicentre collaboration. Genetic testing was done by exome sequencing and targeted arrays. Biochemical assays on serum and urine were performed to delineate the biochemical signature of MOGS-CDG. RESULTS Clinical phenotyping revealed heterogeneity in MOGS-CDG, including neurological, immunological and skeletal phenotypes. Bi-allelic variants in MOGS were identified in 12 individuals from 11 families. The severity in each organ system was variable, without definite genotype correlation. Urine oligosaccharide analysis was consistently abnormal for all affected probands, whereas other biochemical analyses such as serum transferrin analysis was not consistently abnormal. CONCLUSION The clinical phenotype of MOGS-CDG includes multisystemic involvement with variable severity. Molecular analysis, combined with biochemical testing, is important for diagnosis. In MOGS-CDG, urine oligosaccharide analysis via matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry can be used as a reliable biochemical test for screening and confirmation of disease.
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Affiliation(s)
- Shino Shimada
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Bobby G. Ng
- Human Genetics Program, Sanford Burnham Prebys, La Jolla, CA, USA
| | - Amy L. White
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kim. K. Nickander
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Coleman Turgeon
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kristen L. Liedtke
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Christina T. Lam
- Division of Genetic Medicine, Department of Pediatrics, Seattle Children’s Hospital and University of Washington, Seattle, WA, USA
| | | | - Charles M. Lourenço
- Faculdade de Medicina, Centro Universitario Estácio de Ribeirão Preto, Ribeirão Preto, SP, Brazil
- Neurogenetics Unit, Faculdade de Medicina de São José do Rio Preto (FAMERP), São José do Rio Preto, SP, Brazil
| | - Miao He
- Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Dawn S. Peck
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Luis A. Umaña
- Division of Genetics and Metabolism, Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Crescenda L. Uhles
- Department of Genetics, Children’s Medical Center Dallas, Dallas, TX, USA
| | - Devon Haynes
- Division of Genetics, Arnold Palmer Hospital for Children, Orlando Health, Orlando, FL, USA
| | - Patricia G. Wheeler
- Division of Genetics, Arnold Palmer Hospital for Children, Orlando Health, Orlando, FL, USA
| | - Michael J. Bamshad
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Department of Pediatrics, University of Washington, Seattle, WA, USA
| | | | - Tom Cushing
- Division of Pediatric Genetics, Department of Pediatrics, School of Medicine, University of New Mexico, Albuquerque, NM, USA
| | - Ryan Gates
- Division of Medical Genetics, Stanford University, Stanford, CA, USA
| | | | - Heather M. Byers
- Division of Medical Genetics, Stanford University, Stanford, CA, USA
| | | | - Fernanda B. Scalco
- Laboratório de Erros Inatos do Metabolismo/LABEIM, Instituto de Química, Universidade Federal do Rio de Janeiro, Departamento de Bioquímica, Avenida Horácio Macedo, 1281, Bloco C, Polo de Química, Cidade Universitária, Rio de Janeiro, RJ, Brazil
| | - Noelia N. Martinez
- Center for Clinical Genetics, Sydney Children’s Hospital-Randwick, Sydney, New South Wales, Australia
| | - Rani Sachdev
- Center for Clinical Genetics, Sydney Children’s Hospital-Randwick, Sydney, New South Wales, Australia
- School of Women’s & Children’s Health, University of New South Wales, Sydney, New South Wales, Australia
| | - Lacey Smith
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Annapurna Poduri
- Department of Neurology, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA
| | - Stephen Malone
- Department of Neurosciences, Queensland Children’s Hospital, Brisbane, Queensland, Australia
| | - Rebekah Harris
- Department of Medicine, University of Melbourne, Austin Health, Heidelberg, VIC, Australia
| | - Ingrid E. Scheffer
- Department of Medicine, University of Melbourne, Austin Health, Heidelberg, VIC, Australia
- Department of Pediatrics, The University of Melbourne, Royal Children’s Hospital, Parkville, VIC, Australia
- Murdoch Children’s Research Institute and Florey Institute, Melbourne, VIC, Australia
| | - Sergio D. Rosenzweig
- Department of Laboratory Medicine, Clinical Center, and Primary Immunodeficiency Clinic, National Institute of Allergy and Infectious Diseases, National Institute of Health, Bethesda, MD, USA
| | - David R. Adams
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - William A. Gahl
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - May CV. Malicdan
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Senior authors and contributed equally
| | - Kimiyo M. Raymond
- Biochemical Genetics Laboratory, Department of Laboratory Medicine and Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
- Senior authors and contributed equally
| | - Hudson H. Freeze
- Human Genetics Program, Sanford Burnham Prebys, La Jolla, CA, USA
- Senior authors and contributed equally
| | - Lynne A. Wolfe
- Medical Genetic Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Undiagnosed Diseases Program, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD, USA
- Senior authors and contributed equally
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10
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Inactivation of the Lateral Hypothalamus Attenuates Methamphetamine-Induced Conditioned Place Preference through Regulation of Kcnq3 Expression. Int J Mol Sci 2022; 23:ijms23137305. [PMID: 35806315 PMCID: PMC9266452 DOI: 10.3390/ijms23137305] [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: 05/02/2022] [Revised: 06/25/2022] [Accepted: 06/26/2022] [Indexed: 12/03/2022] Open
Abstract
Repeated administration of methylamphetamine (MA) induces MA addiction, which is featured by awfully unpleasant physical and emotional experiences after drug use is terminated. Neurophysiological studies show that the lateral hypothalamus (LH) is involved in reward development and addictive behaviors. Here, we show that repeated administration of MA activates the expression of c-Fos in LH neurons responding to conditioned place preference (CPP). Chemogenetic inhibition of the LH can disrupt the addiction behavior, demonstrating that the LH plays an important role in MA-induced reward processing. Critically, MA remodels the neurons of LH synaptic plasticity, increases intracellular calcium level, and enhances spontaneous current and evoked potentials of neurons compared to the saline group. Furthermore, overexpression of the potassium voltage-gated channel subfamily Q member 3 (Kcnq3) expression can reverse the CPP score and alleviate the occurrence of addictive behaviors. Together, these results unravel a new neurobiological mechanism underlying the MA-induced addiction in the lateral hypothalamus, which could pave the way toward new and effective interventions for this addiction disease.
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11
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Zuberi SM, Wirrell E, Yozawitz E, Wilmshurst JM, Specchio N, Riney K, Pressler R, Auvin S, Samia P, Hirsch E, Galicchio S, Triki C, Snead OC, Wiebe S, Cross JH, Tinuper P, Scheffer IE, Perucca E, Moshé SL, Nabbout R. ILAE classification and definition of epilepsy syndromes with onset in neonates and infants: Position statement by the ILAE Task Force on Nosology and Definitions. Epilepsia 2022; 63:1349-1397. [PMID: 35503712 DOI: 10.1111/epi.17239] [Citation(s) in RCA: 252] [Impact Index Per Article: 126.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 03/20/2022] [Accepted: 03/21/2022] [Indexed: 12/20/2022]
Abstract
The International League Against Epilepsy (ILAE) Task Force on Nosology and Definitions proposes a classification and definition of epilepsy syndromes in the neonate and infant with seizure onset up to 2 years of age. The incidence of epilepsy is high in this age group and epilepsy is frequently associated with significant comorbidities and mortality. The licensing of syndrome specific antiseizure medications following randomized controlled trials and the development of precision, gene-related therapies are two of the drivers defining the electroclinical phenotypes of syndromes with onset in infancy. The principal aim of this proposal, consistent with the 2017 ILAE Classification of the Epilepsies, is to support epilepsy diagnosis and emphasize the importance of classifying epilepsy in an individual both by syndrome and etiology. For each syndrome, we report epidemiology, clinical course, seizure types, electroencephalography (EEG), neuroimaging, genetics, and differential diagnosis. Syndromes are separated into self-limited syndromes, where there is likely to be spontaneous remission and developmental and epileptic encephalopathies, diseases where there is developmental impairment related to both the underlying etiology independent of epileptiform activity and the epileptic encephalopathy. The emerging class of etiology-specific epilepsy syndromes, where there is a specific etiology for the epilepsy that is associated with a clearly defined, relatively uniform, and distinct clinical phenotype in most affected individuals as well as consistent EEG, neuroimaging, and/or genetic correlates, is presented. The number of etiology-defined syndromes will continue to increase, and these newly described syndromes will in time be incorporated into this classification. The tables summarize mandatory features, cautionary alerts, and exclusionary features for the common syndromes. Guidance is given on the criteria for syndrome diagnosis in resource-limited regions where laboratory confirmation, including EEG, MRI, and genetic testing, might not be available.
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Affiliation(s)
- Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children, Institute of Health & Wellbeing, Collaborating Centre of European Reference Network EpiCARE, University of Glasgow, Glasgow, UK
| | - Elaine Wirrell
- Divisions of Child and Adolescent Neurology and Epilepsy, Department of Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - Elissa Yozawitz
- Isabelle Rapin Division of Child Neurology, Saul R. Korey Department of Neurology, Montefiore Medical Center, Bronx, New York, USA
| | - Jo M Wilmshurst
- Department of Paediatric Neurology, Red Cross War Memorial Children's Hospital, Neuroscience Institute, University of Cape Town, Cape Town, South Africa
| | - Nicola Specchio
- Rare and Complex Epilepsy Unit, Department of Neuroscience, Bambino Gesu' Children's Hospital, IRCCS, Member of European Reference Network EpiCARE, Rome, Italy
| | - Kate Riney
- Neurosciences Unit, Queensland Children's Hospital, South Brisbane, Queensland, Australia.,Faculty of Medicine, University of Queensland, St Lucia, Queensland, Australia
| | - Ronit Pressler
- Clinical Neuroscience, UCL- Great Ormond Street Institute of Child Health, London, UK.,Department of Clinical Neurophysiology, Great Ormond Street Hospital for Children NHS Foundation Trust, Member of European Reference Network EpiCARE, London, UK
| | - Stephane Auvin
- AP-HP, Hôpital Robert-Debré, INSERM NeuroDiderot, DMU Innov-RDB, Neurologie Pédiatrique, Member of European Reference Network EpiCARE, Université de Paris, Paris, France
| | - Pauline Samia
- Department of Paediatrics and Child Health, Aga Khan University, Nairobi, Kenya
| | - Edouard Hirsch
- Neurology Epilepsy Unit "Francis Rohmer", INSERM 1258, FMTS, Strasbourg University, Strasbourg, France
| | - Santiago Galicchio
- Child Neurology Department, Victor J Vilela Child Hospital of Rosario, Santa Fe, Argentina
| | - Chahnez Triki
- Child Neurology Department, LR19ES15 Neuropédiatrie, Sfax Medical School, University of Sfax, Sfax, Tunisia
| | - O Carter Snead
- Pediatric Neurology, Hospital for Sick Children, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Samuel Wiebe
- Department of Clinical Neurosciences, University of Calgary, Calgary, Alberta, Canada
| | - J Helen Cross
- Programme of Developmental Neurosciences, UCL NIHR BRC Great Ormond Street Institute of Child Health, Great Ormond Street Hospital for Children, Member of European Reference Network EpiCARE, London, UK.,Young Epilepsy, Lingfield, UK
| | - Paolo Tinuper
- Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna, Italy.,IRCCS Istituto delle Scienze Neurologiche, Bologna, Italy
| | - Ingrid E Scheffer
- Austin Health and Royal Children's Hospital, Florey Institute, Murdoch Children's Research Institute, University of Melbourne, Melbourne, Victoria, Australia
| | - Emilio Perucca
- Department of Neuroscience, Monash University, Melbourne, Victoria, Australia.,Department of Medicine, Austin Health, University of Melbourne, Heidelberg, Victoria, Australia
| | - Solomon L Moshé
- Isabelle Rapin Division of Child Neurology, Saul R. Korey Department of Neurology, Bronx, New York, USA.,Departments of Neuroscience and Pediatrics, Albert Einstein College of Medicine, Bronx, New York, USA.,Montefiore Medical Center, Bronx, New York, USA
| | - Rima Nabbout
- Reference Centre for Rare Epilepsies, Department of Pediatric Neurology, Necker-Enfants Malades University Hospital, APHP, Member of European Reference Network EpiCARE, Institut Imagine, INSERM, UMR 1163, Université Paris cité, Paris, France
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12
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Perry LD, Hogg SL, Bowdin S, Ambegaonkar G, Parker AP. Fifteen-minute consultation: The efficient investigation of infantile and childhood epileptic encephalopathies in the era of modern genomics. Arch Dis Child Educ Pract Ed 2022; 107:80-87. [PMID: 33414255 DOI: 10.1136/archdischild-2020-320606] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/05/2020] [Accepted: 12/09/2020] [Indexed: 11/03/2022]
Abstract
The investigation of children presenting with infantile and childhood epileptic encephalopathies (ICEE) is challenging due to diverse aetiologies, overlapping phenotypes and the relatively low diagnostic yield of MRI, electroencephalography (EEG) and biochemical investigations. Careful history and thorough examination remain essential as these may identify an acquired cause or indicate more targeted investigation for a genetic disorder. Whole exome sequencing (WES) with analysis of a panel of candidate epilepsy genes has increased the diagnostic yield. Whole genome sequencing (WGS), particularly as a trio with both parents' DNA, is likely to supersede WES. Modern genomic investigation impacts on the timing and necessity of other testing. We propose a structured approach for children presenting with ICEE where there is diagnostic uncertainty, emphasising the importance of WGS or, if unavailable, WES early in the investigative process. We note the importance of expert review of all investigations, including radiology, neurophysiology and biochemistry, to confirm the technique used was appropriate as well as the results. It is essential to counsel families on the risks associated with the procedures, the yield of the procedures, findings that are difficult to interpret and implication of 'negative' results. Where children remain without a diagnosis despite comprehensive investigation, we note the importance of ongoing multidisciplinary care.
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Affiliation(s)
- Luke Daniel Perry
- Developmental Neurosciences, University College London, Great Ormond Street Institute of Child Health, London, UK
| | - Sarah Louise Hogg
- Biochemical Genetics Unit, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Sarah Bowdin
- Department of Clinical Genetics, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Gautam Ambegaonkar
- Paediatric Neurology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Alasdair Pj Parker
- Paediatric Neurology, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
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13
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Small-molecule inhibitors of Slack potassium channels as potential therapeutics for childhood epilepsies. Pharm Pat Anal 2022; 11:45-56. [PMID: 35369761 PMCID: PMC9260495 DOI: 10.4155/ppa-2022-0002] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Slack channels are sodium-activated potassium channels that are encoded by the KCNT1 gene. Several KCNT1 gain of function mutations have been linked to malignant migrating partial seizures of infancy. Quinidine is an anti-arrhythmic drug that functions as a moderately potent inhibitor of Slack channels; however, quinidine use is limited by its poor selectivity, safety and pharmacokinetic profile. Slack channels represent an interesting target for developing novel therapeutics for the treatment of malignant migrating partial seizures of infancy and other childhood epilepsies; thus, ongoing efforts are directed toward the discovery of small-molecules that inhibit Slack currents. This review summarizes patent applications published in 2020-2021 that describe the discovery of novel small-molecule Slack inhibitors.
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14
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Huang YC, Chao YC, Lee IC. Syndromic and non-syndromic etiologies causing neonatal hypocalcemic seizures. Front Endocrinol (Lausanne) 2022; 13:998675. [PMID: 36440223 PMCID: PMC9685421 DOI: 10.3389/fendo.2022.998675] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND The diagnosis of neonatal hypocalcemic seizures (HS) in newborns is made based on clinical signs and serum calcium level. Their etiology is broad and diverse, and timely detection and initiation of treatment is essential. METHODS We retrospectively reviewed 1029 patients admitted to the neonatal intensive care unit. Neonatal HS were diagnosed in 16 patients, and we compared etiologies and clinical outcomes, including clinical seizures and neurodevelopment at least over 1 year old. RESULTS The etiologies can be broadly categorized into 5 syndromic and 11 non-syndromic neonatal HS. Syndromic neonatal HS included 3 Digeorge syndrome, 1 Kleefstra syndrome and 1 Alström syndrome. Non-syndromic neonatal HS included 8 vitamin D deficiency, 1 hypoparathyroidism, and 2 hypoxic-ischemic encephalopathy. Patients with syndromic neonatal HS were found to have worse clinical outcomes than those with nonsyndromic HS. In eight patients with vitamin D deficiency, neurodevelopment was normal. Five of five patients (100%) with syndromic HS used two or more antiseizure drugs. However, among patients with non-syndromic neonatal HS, only one of 11 (9.1%) used more than one drug (p = 0.001). CONCLUSION This finding highlighted that syndromic hypocalcemic seizures in newborns have worse neurodevelopmental outcomes and are more often difficult to manage, and would benefit from a genetic diagnostic approach.
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Affiliation(s)
- Yi-Chieh Huang
- Division of Pediatric Neurology, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Yin-Chi Chao
- Division of Pediatric Neurology, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan
| | - Inn-Chi Lee
- Division of Pediatric Neurology, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung, Taiwan
- Institute of Medicine, School of Medicine, Chung Shan Medical University, Taichung, Taiwan
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15
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Long-term course of early onset developmental and epileptic encephalopathy associated with 2q24.3 microduplication. Epilepsy Behav Rep 2022; 19:100547. [PMID: 35733834 PMCID: PMC9207545 DOI: 10.1016/j.ebr.2022.100547] [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: 02/10/2022] [Revised: 04/21/2022] [Accepted: 04/22/2022] [Indexed: 11/25/2022] Open
Abstract
2q24.3 is a region containing a cluster of genes for multiple voltage-gated sodium channels and CNVs in the region cause developmental and epileptic encephalopathy. DEE associated with 2q24.3 duplication have been reported to show early-onset epilepsy, resistant to antiseizure drugs, and severe developmental delay. Drug-resistant epilepsy due to 2q24.3 duplication can be seizure free after infancy. Our case was considered pyridoxine dependent but identifying duplication of 2q24.3 led to the discontinuation of unnecessary medication.
Copy number variations (CNVs) have been related to developmental and epileptic encephalopathy (DEE). The 2q24.3 region includes a cluster of genes for voltage-gated sodium channels (SCN) and CNVs in this region cause DEE. However, the long-term course of DEE with a 2q24.3 duplication has not been described. A 20-year-old female developed epileptic encephalopathy in early infancy that was resistant to various antiseizure medications. Her seizures disappeared after starting vitamin B6 therapy. Therefore, her epilepsy was considered pyridoxine-dependent epilepsy. At 16 years old, whole exome sequencing revealed a 2q24.3 microduplication including SCN1A, SCN2A, SCN3A, SCN7A, and SCN9A. Quantitative PCR detected an increased copy number of 1.3 Mb on 2q24.3 involving these genes, but no gene mutation accounting for pyridoxine-dependent epilepsy. Considering that with this duplication she was reported to be seizure-free after infancy, she was able to be off antiseizure medications including vitamin B6. Our case involvingdrug-resistant epilepsy in early infancy had no recurrent seizures during long-term follow up. Detecting CNVs using whole exome sequencing data was useful to identify a 2q24.3 duplication unassociated with pyridoxine-dependent epilepsy, leading to cessation of unnecessary medications.
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16
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Swanson LC, Ahmed R. Epilepsy Syndromes: Current Classifications and Future Directions. Neurosurg Clin N Am 2021; 33:113-134. [PMID: 34801136 DOI: 10.1016/j.nec.2021.09.009] [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] [Indexed: 12/26/2022]
Abstract
This review describes the clinical presentations and treatment options for commonly recognized epilepsy syndromes in the pediatric age group, based on the 2017 International League Against Epilepsy classification. Structural epilepsies that are amenable to surgical intervention are discussed. Lastly, emerging technologies are reviewed that are expanding our knowledge of underlying epilepsy pathologies and will guide future syndromic classification systems including genetic testing and tissue repositories.
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Affiliation(s)
- Laura C Swanson
- Department of Pediatrics, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E. Chicago Ave. #18, Chicago, IL 60611, USA
| | - Raheel Ahmed
- Department of Neurosurgery, University of Wisconsin-Madison School of Medicine and Public Health, 1675 Highland Avenue #0002, Madison, WI 53705, USA.
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17
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Springer K, Varghese N, Tzingounis AV. Flexible Stoichiometry: Implications for KCNQ2- and KCNQ3-Associated Neurodevelopmental Disorders. Dev Neurosci 2021; 43:191-200. [PMID: 33794528 PMCID: PMC8440324 DOI: 10.1159/000515495] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/25/2021] [Indexed: 11/19/2022] Open
Abstract
KCNQ2 and KCNQ3 pathogenic channel variants have been associated with a spectrum of developmentally regulated diseases that vary in age of onset, severity, and whether it is transient (i.e., benign familial neonatal seizures) or long-lasting (i.e., developmental and epileptic encephalopathy). KCNQ2 and KCNQ3 channels have also emerged as a target for novel antiepileptic drugs as their activation could reduce epileptic activity. Consequently, a great effort has taken place over the last 2 decades to understand the mechanisms that control the assembly, gating, and modulation of KCNQ2 and KCNQ3 channels. The current view that KCNQ2 and KCNQ3 channels assemble as heteromeric channels (KCNQ2/3) forms the basis of our understanding of KCNQ2 and KCNQ3 channelopathies and drug design. Here, we review the evidence that supports the formation of KCNQ2/3 heteromers in neurons. We also highlight functional and transcriptomic studies that suggest channel composition might not be necessarily fixed in the nervous system, but rather is dynamic and flexible, allowing some neurons to express KCNQ2 and KCNQ3 homomers. We propose that to fully understand KCNQ2 and KCNQ3 channelopathies, we need to adopt a more flexible view of KCNQ2 and KCNQ3 channel stoichiometry, which might differ across development, brain regions, cell types, and disease states.
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Affiliation(s)
- Kristen Springer
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Nissi Varghese
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
| | - Anastasios V Tzingounis
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut, USA
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18
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Russ JB, Simmons R, Glass HC. Neonatal Encephalopathy: Beyond Hypoxic-Ischemic Encephalopathy. Neoreviews 2021; 22:e148-e162. [PMID: 33649088 DOI: 10.1542/neo.22-3-e148] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Neonatal encephalopathy is a clinical syndrome of neurologic dysfunction that encompasses a broad spectrum of symptoms and severity, from mild irritability and feeding difficulties to coma and seizures. It is vital for providers to understand that the term "neonatal encephalopathy" is simply a description of the neonate's neurologic status that is agnostic to the underlying etiology. Unfortunately, hypoxic-ischemic encephalopathy (HIE) has become common vernacular to describe any neonate with encephalopathy, but this can be misleading. The term should not be used unless there is evidence of perinatal asphyxia as the primary cause of encephalopathy. HIE is a common cause of neonatal encephalopathy; the differential diagnosis also includes conditions with infectious, vascular, epileptic, genetic/congenital, metabolic, and toxic causes. Because neonatal encephalopathy is estimated to affect 2 to 6 per 1,000 term births, of which HIE accounts for approximately 1.5 per 1,000 term births, (1)(2)(3)(4)(5)(6) neonatologists and child neurologists should familiarize themselves with the evaluation, diagnosis, and treatment of the diverse causes of neonatal encephalopathy. This review begins by discussing HIE, but also helps practitioners extend the differential to consider the broad array of other causes of neonatal encephalopathy, emphasizing the epidemiology, neurologic presentations, diagnostics, imaging findings, and therapeutic strategies for each potential category.
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Affiliation(s)
| | | | - Hannah C Glass
- Division of Child Neurology and.,Department of Pediatrics.,Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA
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19
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García-Hernández JL, Corchete LA, Marcos-Alcalde Í, Gómez-Puertas P, Fons C, Lazo PA. Pathogenic convergence of CNVs in genes functionally associated to a severe neuromotor developmental delay syndrome. Hum Genomics 2021; 15:11. [PMID: 33557955 PMCID: PMC7871650 DOI: 10.1186/s40246-021-00309-4] [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] [Received: 11/17/2020] [Accepted: 01/26/2021] [Indexed: 02/08/2023] Open
Abstract
BACKGROUND Complex developmental encephalopathy syndromes might be the consequence of unknown genetic alterations that are likely to contribute to the full neurological phenotype as a consequence of pathogenic gene combinations. METHODS To identify the additional genetic contribution to the neurological phenotype, we studied as a test case a boy, with a KCNQ2 exon-7 partial duplication, by single-nucleotide polymorphism (SNP) microarray to detect copy-number variations (CNVs). RESULTS The proband presented a cerebral palsy like syndrome with a severe motor and developmental encephalopathy. The SNP array analysis detected in the proband several de novo CNVs, nine partial gene losses (LRRC55, PCDH9, NALCN, RYR3, ELAVL2, CDH13, ATP1A2, SLC17A5, ANO3), and two partial gene duplications (PCDH19, EFNA5). The biological functions of these genes are associated with ion channels such as calcium, chloride, sodium, and potassium with several membrane proteins implicated in neural cell-cell interactions, synaptic transmission, and axon guidance. Pathogenically, these functions can be associated to cerebral palsy, seizures, dystonia, epileptic crisis, and motor neuron dysfunction, all present in the patient. CONCLUSIONS Severe motor and developmental encephalopathy syndromes of unknown origin can be the result of a phenotypic convergence by combination of several genetic alterations in genes whose physiological function contributes to the neurological pathogenic mechanism.
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Affiliation(s)
- Juan L García-Hernández
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca (IBSAL), Departamento de Hematología, Hospital Universitario de Salamanca, Salamanca, Spain
| | - Luis A Corchete
- Instituto de Investigación Biomédica de Salamanca (IBSAL), Departamento de Hematología, Hospital Universitario de Salamanca, Salamanca, Spain.,Network Center for Biomedical Research in Cancer (CIBERONC), Salamanca, Spain
| | - Íñigo Marcos-Alcalde
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain.,Biosciences Research Institute, School of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Madrid, Spain
| | - Paulino Gómez-Puertas
- Centro de Biología Molecular Severo Ochoa, CSIC-Universidad Autónoma de Madrid, Cantoblanco, Madrid, Spain
| | - Carmen Fons
- Neurology Department, Hospital Sant Joan de Déu, Sant Joan de Déu Research Institute, Esplugues de Llobregat, Barcelona and CIBERER, Instituto de Salud Carlos III, Barcelona, Spain.
| | - Pedro A Lazo
- Molecular Mechanisms of Cancer Program, Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC), Universidad de Salamanca, Salamanca, Spain. .,Instituto de Investigación Biomédica de Salamanca (IBSAL), Departamento de Hematología, Hospital Universitario de Salamanca, Salamanca, Spain.
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20
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Scher MS. "The First Thousand Days" Define a Fetal/Neonatal Neurology Program. Front Pediatr 2021; 9:683138. [PMID: 34408995 PMCID: PMC8365757 DOI: 10.3389/fped.2021.683138] [Citation(s) in RCA: 39] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/27/2021] [Indexed: 01/11/2023] Open
Abstract
Gene-environment interactions begin at conception to influence maternal/placental/fetal triads, neonates, and children with short- and long-term effects on brain development. Life-long developmental neuroplasticity more likely results during critical/sensitive periods of brain maturation over these first 1,000 days. A fetal/neonatal program (FNNP) applying this perspective better identifies trimester-specific mechanisms affecting the maternal/placental/fetal (MPF) triad, expressed as brain malformations and destructive lesions. Maladaptive MPF triad interactions impair progenitor neuronal/glial populations within transient embryonic/fetal brain structures by processes such as maternal immune activation. Destructive fetal brain lesions later in pregnancy result from ischemic placental syndromes associated with the great obstetrical syndromes. Trimester-specific MPF triad diseases may negatively impact labor and delivery outcomes. Neonatal neurocritical care addresses the symptomatic minority who express the great neonatal neurological syndromes: encephalopathy, seizures, stroke, and encephalopathy of prematurity. The asymptomatic majority present with neurologic disorders before 2 years of age without prior detection. The developmental principle of ontogenetic adaptation helps guide the diagnostic process during the first 1,000 days to identify more phenotypes using systems-biology analyses. This strategy will foster innovative interdisciplinary diagnostic/therapeutic pathways, educational curricula, and research agenda among multiple FNNP. Effective early-life diagnostic/therapeutic programs will help reduce neurologic disease burden across the lifespan and successive generations.
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Affiliation(s)
- Mark S Scher
- Division of Pediatric Neurology, Department of Pediatrics, Fetal/Neonatal Neurology Program, Emeritus Scholar Tenured Full Professor in Pediatrics and Neurology, Case Western Reserve University School of Medicine, Cleveland, OH, United States
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21
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Miziak B, Czuczwar S. Advances in the design and discovery of novel small molecule drugs for the treatment of Dravet Syndrome. Expert Opin Drug Discov 2020; 16:579-593. [PMID: 33275464 DOI: 10.1080/17460441.2021.1857722] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Introduction: Dravet syndrome (severe myoclonic epilepsy in infancy) begins in the first year of life characterized by generalized or unilateral clonic seizures that are frequently triggered by high fever. A subsequent worsening stage occurs (in years 1-4 of life) and seizure activity is accompanied by disturbed psychomotor development. The third stage of the disease, known as the 'stabilization phase,' is associated with seizures and intellectual impairment. Of note, a mutation in the voltage-gated sodium-channel gene α 1 subunit (SCN1A) has been found in around 85% of patients with Dravet syndrome.Areas covered: The authors review the current treatment strategies as well as potential drugs in the initial stages of clinical evaluation. The authors also review drugs with protective activity in mice models of Dravet syndrome.Expert opinion: Experimental data and results from initial clinical studies have brought attention to several drugs with various mechanisms of action including: ataluren (a suppressant of premature stop codons; under clinical evaluation), EPX-100, EPX-200, fenfluramine (serotonin modulators), soticlestat (an 24-hydroxylase cholesterol enzyme inhibitor), SPN-817 (an inhibitor of acetylcholinesterase), verapamil (a voltage-dependent calcium channel inhibitor) and STK-001 (an antisense oligonucleotide). The latter is scheduled for clinical evaluation.
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Affiliation(s)
- Barbara Miziak
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
| | - Stanisław Czuczwar
- Department of Pathophysiology, Medical University of Lublin, Lublin, Poland
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Hong SY, Yang JJ, Li SY, Lee IC. A Wide Spectrum of Genetic Disorders Causing Severe Childhood Epilepsy in Taiwan: A Case Series of Ultrarare Genetic Cause and Novel Mutation Analysis in a Pilot Study. J Pers Med 2020; 10:jpm10040281. [PMID: 33333793 PMCID: PMC7765181 DOI: 10.3390/jpm10040281] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Pediatric epileptic encephalopathy and severe neurological disorders comprise a group of heterogenous diseases. We used whole-exome sequencing (WES) to identify genetic defects in pediatric patients. METHODS Patients with refractory seizures using ≥2 antiepileptic drugs (AEDs) receiving one AED and having neurodevelopmental regression or having severe neurological or neuromuscular disorders with unidentified causes were enrolled, of which 54 patients fulfilled the inclusion criteria, were enrolled, and underwent WES. RESULTS Genetic diagnoses were confirmed in 24 patients. In the seizure group, KCNQ2, SCN1A, TBCID 24, GRIN1, IRF2BPL, MECP2, OSGEP, PACS1, PIGA, PPP1CB, SMARCA4, SUOX, SZT2, UBE3A, 16p13.11 microdeletion, [4p16.3p16.1(68,345-7,739,782)X1, 17q25.1q25.3(73,608,322-81,041,938)X3], and LAMA2 were identified. In the nonseizure group, SCN2A, SPTBN2, DMD, and FBN1 were identified. Ten novel mutations were identified. The recurrent genes included SCN1A, KCNQ2, and TBCID24. Male pediatric patients had a significantly higher (57% vs. 29%; p < 0.05, odds ratio = 3.18) yield than their female counterparts. Seventeen genes were identified from the seizure groups, of which 82% were rare genetic etiologies for childhood seizure and did not appear recurrently in the case series. CONCLUSIONS Wide genetic variation was identified for severe childhood seizures by WES. WES had a high yield, particularly in male infantile patients.
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Affiliation(s)
- Syuan-Yu Hong
- Division of Pediatric Neurology, Department of Pediatrics, Children’s Hospital, China Medical University Hospital, Taichung 40447, Taiwan;
| | - Jiann-Jou Yang
- Genetics Laboratory and Department of Biomedical Sciences, Chung Shan Medical University, Taichung 40201, Taiwan; (J.-J.Y.); (S.-Y.L.)
| | - Shuan-Yow Li
- Genetics Laboratory and Department of Biomedical Sciences, Chung Shan Medical University, Taichung 40201, Taiwan; (J.-J.Y.); (S.-Y.L.)
| | - Inn-Chi Lee
- Division of Pediatric Neurology, Department of Pediatrics, Chung Shan Medical University Hospital, Taichung 40201, Taiwan
- Institute of Medicine, School of Medicine, Chung Shan Medical University, Taichung 40201, Taiwan
- Correspondence: ; Tel.: +886-4-2473-9535; Fax: +886-4-2471-0934
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De Novo Truncating Variants in the Last Exon of SEMA6B Cause Progressive Myoclonic Epilepsy. Am J Hum Genet 2020; 106:549-558. [PMID: 32169168 DOI: 10.1016/j.ajhg.2020.02.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/19/2020] [Indexed: 12/22/2022] Open
Abstract
De novo variants (DNVs) cause many genetic diseases. When DNVs are examined in the whole coding regions of genes in next-generation sequencing analyses, pathogenic DNVs often cluster in a specific region. One such region is the last exon and the last 50 bp of the penultimate exon, where truncating DNVs cause escape from nonsense-mediated mRNA decay [NMD(-) region]. Such variants can have dominant-negative or gain-of-function effects. Here, we first developed a resource of rates of truncating DNVs in NMD(-) regions under the null model of DNVs. Utilizing this resource, we performed enrichment analysis of truncating DNVs in NMD(-) regions in 346 developmental and epileptic encephalopathy (DEE) trios. We observed statistically significant enrichment of truncating DNVs in semaphorin 6B (SEMA6B) (p value: 2.8 × 10-8; exome-wide threshold: 2.5 × 10-6). The initial analysis of the 346 individuals and additional screening of 1,406 and 4,293 independent individuals affected by DEE and developmental disorders collectively identified four truncating DNVs in the SEMA6B NMD(-) region in five individuals who came from unrelated families (p value: 1.9 × 10-13) and consistently showed progressive myoclonic epilepsy. RNA analysis of lymphoblastoid cells established from an affected individual showed that the mutant allele escaped NMD, indicating stable production of the truncated protein. Importantly, heterozygous truncating variants in the NMD(+) region of SEMA6B are observed in general populations, and SEMA6B is most likely loss-of-function tolerant. Zebrafish expressing truncating variants in the NMD(-) region of SEMA6B orthologs displayed defective development of brain neurons and enhanced pentylenetetrazole-induced seizure behavior. In summary, we show that truncating DNVs in the final exon of SEMA6B cause progressive myoclonic epilepsy.
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