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Conecker G, Xia MY, Hecker J, Achkar C, Cukiert C, Devries S, Donner E, Fitzgerald MP, Gardella E, Hammer M, Hegde A, Hu C, Kato M, Luo T, Schreiber JM, Wang Y, Kooistra T, Oudin M, Waldrop K, Youngquist JT, Zhang D, Wirrell E, Perry MS. Global modified Delphi consensus on diagnosis, phenotypes, and treatment of SCN8A-related epilepsy and/or neurodevelopmental disorders. Epilepsia 2024; 65:2322-2338. [PMID: 38802994 DOI: 10.1111/epi.17992] [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: 11/13/2023] [Revised: 04/08/2024] [Accepted: 04/08/2024] [Indexed: 05/29/2024]
Abstract
OBJECTIVE We aimed to develop consensus for diagnosis/management of SCN8A-related disorders. Utilizing a modified Delphi process, a global cohort of experienced clinicians and caregivers provided input on diagnosis, phenotypes, treatment, and management of SCN8A-related disorders. METHODS A Core Panel (13 clinicians, one researcher, six caregivers), divided into three subgroups (diagnosis/phenotypes, treatment, comorbidities/prognosis), performed a literature review and developed questions for the modified Delphi process. Twenty-eight expert clinicians, one researcher, and 13 caregivers from 16 countries participated in the subsequent three survey rounds. We defined consensus as follows: strong consensus, ≥80% fully agree; moderate consensus, ≥80% fully/partially agree, <10% disagree; and modest consensus, 67%-79% fully/partially agree, <10% disagree. RESULTS Early diagnosis is important for long-term clinical outcomes in SCN8A-related disorders. There are five phenotypes: three with early seizure onset (severe developmental and epileptic encephalopathy [DEE], mild/moderate DEE, self-limited (familial) infantile epilepsy [SeL(F)IE]) and two with later/no seizure onset (neurodevelopmental delay with generalized epilepsy [NDDwGE], NDD without epilepsy [NDDwoE]). Caregivers represented six patients with severe DEE, five mild/moderate DEE, one NDDwGE, and one NDDwoE. Phenotypes vary by age at seizures/developmental delay onset, seizure type, electroencephalographic/magnetic resonance imaging findings, and first-line treatment. Gain of function (GOF) versus loss of function (LOF) is valuable for informing treatment. Sodium channel blockers are optimal first-line treatment for GOF, severe DEE, mild/moderate DEE, and SeL(F)IE; levetiracetam is relatively contraindicated in GOF patients. First-line treatment for NDDwGE is valproate, ethosuximide, or lamotrigine; sodium channel blockers are relatively contraindicated in LOF patients. SIGNIFICANCE This is the first-ever global consensus for the diagnosis and treatment of SCN8A-related disorders. This consensus will reduce knowledge gaps in disease recognition and inform preferred treatment across this heterogeneous disorder. Consensus of this type allows more clinicians to provide evidence-based care and empowers SCN8A families to advocate for their children.
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Affiliation(s)
- Gabrielle Conecker
- International SCN8A Alliance, a project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
| | - Maya Y Xia
- International SCN8A Alliance, a project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
- COMBINEDBrain, Brentwood, Tennessee, USA
| | - JayEtta Hecker
- International SCN8A Alliance, a project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
| | - Christelle Achkar
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Cristine Cukiert
- Department of Neurology and Neurosurgery, Cukiert Clinic, São Paulo, Brazil
| | - Seth Devries
- Pediatric Neurology, Helen DeVos Children's Hospital, Grand Rapids, Michigan, USA
| | - Elizabeth Donner
- Division of Neurology, Department of Paediatrics, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Mark P Fitzgerald
- Epilepsy Neurogenetics Initiative, Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Elena Gardella
- Department of Epilepsy Genetics and Personalized Treatment, Danish Epilepsy Center, Dianalund, Denmark
- University of Southern Denmark, Odense, Denmark
| | - Michael Hammer
- International SCN8A Alliance, a project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
- Department of Neurology and Bio5 Institute, University of Arizona, Tucson, Arizona, USA
| | - Anaita Hegde
- Department of Pediatric Neurosciences, Bai Jerbai Wadia Hospital for Children, Mumbai, India
| | - Chunhui Hu
- Department of Neurology, Fujian Children's Hospital (Fujian Branch of Shanghai Children's Medical Center), National Regional Medical Center, Fuzhou, China
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Epilepsy Medical Center, Showa University Hospital, Shinagawa-ku, Tokyo, Japan
| | - Tian Luo
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - John M Schreiber
- Department of Neurology, Children's National Hospital, Washington, District of Columbia, USA
| | - Yi Wang
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Tammy Kooistra
- International SCN8A Alliance Caregiver Representative, Washington, District of Columbia, USA
| | - Madeleine Oudin
- International SCN8A Alliance, a project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
- International SCN8A Alliance Caregiver Representative, Washington, District of Columbia, USA
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts, USA
| | - Kayla Waldrop
- International SCN8A Alliance Caregiver Representative, Washington, District of Columbia, USA
| | - J Tyler Youngquist
- International SCN8A Alliance Caregiver Representative, Washington, District of Columbia, USA
| | - Dennis Zhang
- International SCN8A Alliance Caregiver Representative, Washington, District of Columbia, USA
| | - Elaine Wirrell
- Child and Adolescent Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - M Scott Perry
- Jane and John Justin Institute for Mind Health, Neurosciences Center, Cook Children's Medical Center, Fort Worth, Texas, USA
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Conecker G, Xia MY, Hecker J, Achkar C, Cukiert C, Devries S, Donner E, Fitzgerald M, Gardella E, Hammer M, Hegde A, Hu C, Kato M, Luo T, Schreiber JM, Wang Y, Kooistra T, Oudin M, Waldrop K, Youngquist JT, Zhang D, Wirrell E, Perry MS. Global modified-Delphi consensus on comorbidities and prognosis of SCN8A-related epilepsy and/or neurodevelopmental disorders. Epilepsia 2024; 65:2308-2321. [PMID: 38802989 DOI: 10.1111/epi.17991] [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: 11/13/2023] [Revised: 04/05/2024] [Accepted: 04/08/2024] [Indexed: 05/29/2024]
Abstract
OBJECTIVES We aimed to develop consensus on comorbidities (frequency, severity, and prognosis) and overall outcomes in epilepsy, development, and cognition for the five phenotypes of SCN8A-related disorders. METHODS A core panel consisting of 13 clinicians, 1 researcher, and 6 caregivers was formed and split into three workgroups. One group focused on comorbidities and prognosis. All groups performed a literature review and developed questions for use in a modified-Delphi process. Twenty-eight clinicians, one researcher, and 13 caregivers from 16 countries participated in three rounds of the modified-Delphi process. Consensus was defined as follows: strong consensus ≥80% fully agree; moderate consensus ≥80% fully or partially agree, <10% disagree; and modest consensus 67%-79% fully or partially agree, <10% disagree. RESULTS Consensus was reached on the presence of 14 comorbidities in patients with Severe Developmental and Epileptic Encephalopathy (Severe DEE) spanning non-seizure neurological disorders and other organ systems; impacts were mostly severe and unlikely to improve or resolve. Across Mild/Moderate Developmental and Epileptic Encephalopathy (Mild/Moderate DEE), Neurodevelopmental Delay with Generalized Epilepsy (NDDwGE), and NDD without Epilepsy (NDDwoE) phenotypes, cognitive and sleep-related comorbidities as well as fine and gross motor delays may be present but are less severe and more likely to improve compared to Severe DEE. There was no consensus on comorbidities in the SeL(F)IE phenotype but strong conesensus that seizures would largely resolve. Seizure freedom is rare in patients with Severe DEE but may occur in some with Mild/Moderate DEE and NDDwGE. SIGNIFICANCE Significant comorbidities are present in most phenotypes of SCN8A-related disorders but are most severe and pervasive in the Severe DEE phenotype. We hope that this work will improve recognition, early intervention, and long-term management for patients with these comorbidities and provide the basis for future evidence-based studies on optimal treatments of SCN8A-related disorders. Identifying the prognosis of patients with SCN8A-related disorders will also improve care and quality-of-life for patients and their caregivers.
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Affiliation(s)
- Gabrielle Conecker
- International SCN8A Alliance, a Project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
| | - Maya Y Xia
- International SCN8A Alliance, a Project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
- COMBINEDBrain, Brentwood, Tennessee, USA
| | - JayEtta Hecker
- International SCN8A Alliance, a Project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
| | - Christelle Achkar
- Division of Epilepsy and Clinical Neurophysiology and Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Cristine Cukiert
- Department of Neurology and Neurosurgery, Cukiert Clinic, São Paulo, Brazil
| | - Seth Devries
- Pediatric Neurology, Helen DeVos Children's Hospital, Grand Rapids, Michigan, USA
| | - Elizabeth Donner
- Division of Neurology, Department of Paediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Mark Fitzgerald
- Epilepsy Neurogenetics Initiative, Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Elena Gardella
- Department of Epilepsy Genetics and Personalized Treatment, The Danish Epilepsy Center, Dianalund, Denmark
- University of Southern Denmark, Odense, Denmark
| | - Michael Hammer
- Department of Neurology and Bio5 Institute, University of Arizona, Tucson, Arizona, USA
| | - Anaita Hegde
- Department of Pediatric Neurosciences, Bai Jerbai Wadia Hospital for Children, Mumbai, Maharashtra, India
| | - Chunhui Hu
- Department of Neurology, Fujian Children's Hospital (Fujian Branch of Shanghai Children's Medical Center), National Regional Medical Center, Fuzhou, China
| | - Mitsuhiro Kato
- Department of Pediatrics, Showa University School of Medicine, Epilepsy Medical Center, Showa University Hospital, Shinagawa-ku, Japan
| | - Tian Luo
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - John M Schreiber
- Department of Neurology, Children's National Hospital, Washington, District of Columbia, USA
| | - Yi Wang
- Department of Neurology, Children's Hospital of Fudan University, National Children's Medical Center, Shanghai, China
| | - Tammy Kooistra
- International SCN8A Alliance, a Project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
- International SCN8A Alliance Caregiver Representative, Global
| | - Madeleine Oudin
- International SCN8A Alliance, a Project of Decoding Developmental Epilepsies, Washington, District of Columbia, USA
- International SCN8A Alliance Caregiver Representative, Global
- Department of Biomedical Engineering, 200 College Avenue, Tufts University, Medford, Massachusetts, USA
| | - Kayla Waldrop
- International SCN8A Alliance Caregiver Representative, Global
| | | | - Dennis Zhang
- International SCN8A Alliance Caregiver Representative, Global
| | - Elaine Wirrell
- Child and Adolescent Neurology, Mayo Clinic, Rochester, Minnesota, USA
| | - M Scott Perry
- Jane and John Justin Institute for Mind Health, Neurosciences Center, Cook Children's Medical Center, Texas, USA
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Paprocka J, Steinborn B, Krygier M, Winczewska-Wiktor A, Przyslo L, Hutny M, Hoffman-Zacharska D, Mazurkiewicz H, Kochanowska I, Zebrowska J, Zawadzka M, Piasecki L, Mazurkiewicz-Beldzinska M. Genotype-phenotype correlations in Polish patients with SCN8A-related epilepsy: A multicentre observational study. Seizure 2024; 120:201-209. [PMID: 39047613 DOI: 10.1016/j.seizure.2024.06.017] [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: 10/19/2023] [Revised: 06/19/2024] [Accepted: 06/20/2024] [Indexed: 07/27/2024] Open
Abstract
BACKGROUND Voltage-gated sodium channels are involved in the initial depolarisation of neurones. As such, they play important roles in neurotransmission. Variants in the genes encoding these channels may lead to altered functionality and neurodevelopmental disorders. Pathogenic variants of SCN8A, which encodes the voltage-gated Na+ channel Nav1.6, have been associated with various encephalopathies characterised by developmental delay and epileptic seizures. Herein, we discuss the genotype-phenotype associations in a group of 17 novel Polish patients with SCN8A mutations, further expanding the molecular and phenotypic spectrum of SCN8A-related diseases. METHODS The participants were recruited from five clinical centres in Poland. Pathogenic and likely pathogenic SCN8A variants were identified using a next-generation sequencing (NGS) panel and exome sequencing, respectively. Magnetic resonance imaging (MRI) and electroencephalography (EEG) recordings were performed to obtain relevant clinical data on brain malformations and epileptic seizures. RESULTS Three phenotypes were observed in the study group: developmental and epileptic encephalopathy, early onset epileptic encephalopathy, and neurodevelopmental disorders without epilepsy. Patients in the first two phenotypic subgroups presented with epileptic seizures within the first few months of life. Their semiology evolved with age, comprising mostly tonic, clonic, and tonic-clonic seizures, with eyelid myoclonia, myoclonic seizures, and epileptic spasms. The most prevalent neurological feature was developmental delay. Alterations in muscle tone were more frequent than in previous reports. CONCLUSIONS Seventeen patients with 11 novel mutations in SCN8A had alterations in muscular tone accompanied by typical features of SCN8A-related encephalopathies (i.e., developmental delay and a wide range of seizures).
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Affiliation(s)
- Justyna Paprocka
- Department of Pediatric Neurology, Medical University of Silesia, Katowice, Poland.
| | | | - Magdalena Krygier
- Department of Developmental Neurology, Medical University of Gdansk, Gdansk, Poland
| | | | - Lukasz Przyslo
- Polish Mother's Memorial Hospital Research Institute, Lodz, Poland
| | - Michał Hutny
- Student's Scientific Society, Department of Pediatric Neurology, Medical University of Silesia, Katowice, Poland
| | | | - Hanna Mazurkiewicz
- Clinic of Pediatric Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Iwona Kochanowska
- Individual Medical Practice in Pediatric Neurology, Szczecin, Poland
| | - Joanna Zebrowska
- Clinic of Pediatric Neurology, Institute of Mother and Child, Warsaw, Poland
| | - Marta Zawadzka
- Department of Developmental Neurology, Medical University of Gdansk, Gdansk, Poland
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Wong JC, Escayg A. Carvedilol increases seizure resistance in a mouse model of SCN8A-derived epilepsy. Front Pharmacol 2024; 15:1397225. [PMID: 38895634 PMCID: PMC11184058 DOI: 10.3389/fphar.2024.1397225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 05/14/2024] [Indexed: 06/21/2024] Open
Abstract
Patients with mutations that alter the function of the sodium channel SCN8A present with a range of clinical features, including mild to severe seizures, developmental delay, intellectual disability, autism, feeding dysfunction, motor impairment, and hypotonia. In an effort to identify compounds that could be potentially beneficial in SCN8A-associated epilepsy, Atkin et al. conducted an in vitro screen which resulted in the identification of 90 compounds that effectively reduced sodium influx into the cells expressing the human SCN8A R1872Q mutation. The top compounds that emerged from this screen included amitriptyline, carvedilol, and nilvadipine. In the current study, we evaluated the ability of these three compounds to increase resistance to 6 Hz or pentylenetetrazole (PTZ)-induced seizures in wild-type CF1 mice and in a mouse line expressing the human SCN8A R1620L mutation. We also evaluated the effects of fenfluramine administration, which was recently associated with a 60%-90% decrease in seizure frequency in three patients with SCN8A-associated epilepsy. While amitriptyline, carvedilol, and fenfluramine provided robust protection against induced seizures in CF1 mice, only carvedilol was able to significantly increase resistance to 6 Hz- and PTZ-induced seizures in RL/+ mutants. These results provide support for further evaluation of carvedilol as a potential treatment for patients with SCN8A mutations.
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Affiliation(s)
- Jennifer C. Wong
- Department of Human Genetics, Emory University, Atlanta, GA, United States
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5
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Roelens R, Peigneur ANF, Voets T, Vriens J. Neurodevelopmental disorders caused by variants in TRPM3. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2024; 1871:119709. [PMID: 38522727 DOI: 10.1016/j.bbamcr.2024.119709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/15/2024] [Accepted: 03/18/2024] [Indexed: 03/26/2024]
Abstract
Developmental and epileptic encephalopathies (DEE) are a broad and varied group of disorders that affect the brain and are characterized by epilepsy and comorbid intellectual disability (ID). These conditions have a broad spectrum of symptoms and can be caused by various underlying factors, including genetic mutations, infections, and other medical conditions. The exact cause of DEE remains largely unknown in the majority of cases. However, in around 25 % of patients, rare nonsynonymous coding variants in genes encoding ion channels, cell-surface receptors, and other neuronally expressed proteins are identified. This review focuses on a subgroup of DEE patients carrying variations in the gene encoding the Transient Receptor Potential Melastatin 3 (TRPM3) ion channel, where recent data indicate that gain-of-function of TRPM3 channel activity underlies a spectrum of dominant neurodevelopmental disorders.
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Affiliation(s)
- Robbe Roelens
- Laboratory of Endometrium, Endometriosis and Reproductive Medicine, Department of Development and Regeneration, KU Leuven, Leuven, Belgium; Laboratory of Ion Channel Research, Department of Molecular Medicine, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Ana Nogueira Freitas Peigneur
- Laboratory of Ion Channel Research, Department of Molecular Medicine, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium
| | - Thomas Voets
- Laboratory of Ion Channel Research, Department of Molecular Medicine, KU Leuven, Leuven, Belgium; VIB-KU Leuven Center for Brain and Disease Research, Leuven, Belgium.
| | - Joris Vriens
- Laboratory of Endometrium, Endometriosis and Reproductive Medicine, Department of Development and Regeneration, KU Leuven, Leuven, Belgium; Laboratory of Ion Channel Research, Department of Molecular Medicine, KU Leuven, Leuven, Belgium.
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Quinn S, Zhang N, Fenton TA, Brusel M, Muruganandam P, Peleg Y, Giladi M, Haitin Y, Lerche H, Bassan H, Liu Y, Ben-Shalom R, Rubinstein M. Complex biophysical changes and reduced neuronal firing in an SCN8A variant associated with developmental delay and epilepsy. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167127. [PMID: 38519006 DOI: 10.1016/j.bbadis.2024.167127] [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: 12/17/2023] [Revised: 03/07/2024] [Accepted: 03/12/2024] [Indexed: 03/24/2024]
Abstract
Mutations in the SCN8A gene, encoding the voltage-gated sodium channel NaV1.6, are associated with a range of neurodevelopmental syndromes. The p.(Gly1625Arg) (G1625R) mutation was identified in a patient diagnosed with developmental epileptic encephalopathy (DEE). While most of the characterized DEE-associated SCN8A mutations were shown to cause a gain-of-channel function, we show that the G1625R variant, positioned within the S4 segment of domain IV, results in complex effects. Voltage-clamp analyses of NaV1.6G1625R demonstrated a mixture of gain- and loss-of-function properties, including reduced current amplitudes, increased time constant of fast voltage-dependent inactivation, a depolarizing shift in the voltage dependence of activation and inactivation, and increased channel availability with high-frequency repeated depolarization. Current-clamp analyses in transfected cultured neurons revealed that these biophysical properties caused a marked reduction in the number of action potentials when firing was driven by the transfected mutant NaV1.6. Accordingly, computational modeling of mature cortical neurons demonstrated a mild decrease in neuronal firing when mimicking the patients' heterozygous SCN8A expression. Structural modeling of NaV1.6G1625R suggested the formation of a cation-π interaction between R1625 and F1588 within domain IV. Double-mutant cycle analysis revealed that this interaction affects the voltage dependence of inactivation in NaV1.6G1625R. Together, our studies demonstrate that the G1625R variant leads to a complex combination of gain and loss of function biophysical changes that result in an overall mild reduction in neuronal firing, related to the perturbed interaction network within the voltage sensor domain, necessitating personalized multi-tiered analysis for SCN8A mutations for optimal treatment selection.
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Affiliation(s)
- Shir Quinn
- Goldschleger Eye Research Institute, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Nan Zhang
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Timothy A Fenton
- Neurology Department, MIND Institute, University of California, Davis, Sacramento, CA, United States
| | - Marina Brusel
- Goldschleger Eye Research Institute, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Preethi Muruganandam
- Neurology Department, MIND Institute, University of California, Davis, Sacramento, CA, United States
| | - Yoav Peleg
- Life Sciences Core Facilities, Weizmann Institute of Science, Rehovot, Israel
| | - Moshe Giladi
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Yoni Haitin
- Department of Physiology and Pharmacology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Haim Bassan
- Pediatric Neurology and Development Center, Shamir Medical Center (Assaf Harofeh), Zerifin, Israel; Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Yuanyuan Liu
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
| | - Roy Ben-Shalom
- Neurology Department, MIND Institute, University of California, Davis, Sacramento, CA, United States.
| | - Moran Rubinstein
- Goldschleger Eye Research Institute, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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7
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Lin S, Gade AR, Wang HG, Niemeyer JE, Galante A, DiStefano I, Towers P, Nunez J, Schwartz TH, Rajadhyaksha AM, Pitt GS. Interneuron FGF13 regulates seizure susceptibility via a sodium channel-independent mechanism. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.18.590019. [PMID: 38659789 PMCID: PMC11042350 DOI: 10.1101/2024.04.18.590019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Developmental and Epileptic Encephalopathies (DEEs), a class of devastating neurological disorders characterized by recurrent seizures and exacerbated by disruptions to excitatory/inhibitory balance in the brain, are commonly caused by mutations in ion channels. Disruption of, or variants in, FGF13 were implicated as causal for a set of DEEs, but the underlying mechanisms were clouded because FGF13 is expressed in both excitatory and inhibitory neurons, FGF13 undergoes extensive alternative splicing producing multiple isoforms with distinct functions, and the overall roles of FGF13 in neurons are incompletely cataloged. To overcome these challenges, we generated a set of novel cell type-specific conditional knockout mice. Interneuron-targeted deletion of Fgf13 led to perinatal mortality associated with extensive seizures and impaired the hippocampal inhibitory/excitatory balance while excitatory neuron-targeted deletion of Fgf13 caused no detectable seizures and no survival deficits. While best studied as a voltage-gated sodium channel (Nav) regulator, we observed no effect of Fgf13 ablation in interneurons on Navs but rather a marked reduction in K+ channel currents. Re-expressing different Fgf13 splice isoforms could partially rescue deficits in interneuron excitability and restore K+ channel current amplitude. These results enhance our understanding of the molecular mechanisms that drive the pathogenesis of Fgf13-related seizures and expand our understanding of FGF13 functions in different neuron subsets.
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Affiliation(s)
- Susan Lin
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY
| | - Aravind R. Gade
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY
| | - Hong-Gang Wang
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY
| | - James E. Niemeyer
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, NY
| | - Allison Galante
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY
| | | | - Patrick Towers
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY
| | - Jorge Nunez
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY
| | - Theodore H. Schwartz
- Department of Neurological Surgery and Brain and Mind Research Institute, Weill Cornell Medicine of Cornell University, New York Presbyterian Hospital, New York, NY
| | - Anjali M. Rajadhyaksha
- Department of Pediatrics, Division of Pediatric Neurology, Weill Cornell Medicine, New York, NY; Brain and Mind Research Institute, Weill Cornell Medicine, New York, NY
| | - Geoffrey S. Pitt
- Cardiovascular Research Institute, Weill Cornell Medicine, New York, NY
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8
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Hack JB, Watkins JC, Hammer MF. Machine learning models reveal distinct disease subgroups and improve diagnostic and prognostic accuracy for individuals with pathogenic SCN8A gain-of-function variants. Biol Open 2024; 13:bio060286. [PMID: 38466077 PMCID: PMC11070785 DOI: 10.1242/bio.060286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 03/01/2024] [Indexed: 03/12/2024] Open
Abstract
Distinguishing clinical subgroups for patients suffering with diseases characterized by a wide phenotypic spectrum is essential for developing precision therapies. Patients with gain-of-function (GOF) variants in the SCN8A gene exhibit substantial clinical heterogeneity, viewed historically as a linear spectrum ranging from mild to severe. To test for hidden clinical subgroups, we applied two machine-learning algorithms to analyze a dataset of patient features collected by the International SCN8A Patient Registry. We used two research methodologies: a supervised approach that incorporated feature severity cutoffs based on clinical conventions, and an unsupervised approach employing an entirely data-driven strategy. Both approaches found statistical support for three distinct subgroups and were validated by correlation analyses using external variables. However, distinguishing features of the three subgroups within each approach were not concordant, suggesting a more complex phenotypic landscape. The unsupervised approach yielded strong support for a model involving three partially ordered subgroups rather than a linear spectrum. Application of these machine-learning approaches may lead to improved prognosis and clinical management of individuals with SCN8A GOF variants and provide insights into the underlying mechanisms of the disease.
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Affiliation(s)
- Joshua B. Hack
- BIO5 Institute is Keating Research Building, 1657 E Helen Street, University of Arizona, Tucson, AZ 85721, USA
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, AZ 85721, USA
| | - Michael F. Hammer
- BIO5 Institute is Keating Research Building, 1657 E Helen Street, University of Arizona, Tucson, AZ 85721, USA
- BIO5 Institute, Neurology Department, University of Arizona, Tucson, AZ 85721, USA
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9
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Bacq A, Depaulis A, Castagné V, Le Guern ME, Wirrell EC, Verleye M. An Update on Stiripentol Mechanisms of Action: A Narrative Review. Adv Ther 2024; 41:1351-1371. [PMID: 38443647 PMCID: PMC10960919 DOI: 10.1007/s12325-024-02813-0] [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: 01/09/2024] [Accepted: 02/02/2024] [Indexed: 03/07/2024]
Abstract
Stiripentol (Diacomit®) (STP) is an orally active antiseizure medication (ASM) indicated as adjunctive therapy, for the treatment of seizures associated with Dravet syndrome (DS), a severe form of childhood epilepsy, in conjunction with clobazam and, in some regions valproic acid. Since the discovery of STP, several mechanisms of action (MoA) have been described that may explain its specific effect on seizures associated with DS. STP is mainly considered as a potentiator of gamma-aminobutyric acid (GABA) neurotransmission: (i) via uptake blockade, (ii) inhibition of degradation, but also (iii) as a positive allosteric modulator of GABAA receptors, especially those containing α3 and δ subunits. Blockade of voltage-gated sodium and T-type calcium channels, which is classically associated with anticonvulsant and neuroprotective properties, has also been demonstrated for STP. Finally, several studies indicate that STP could regulate glucose energy metabolism and inhibit lactate dehydrogenase. STP is also an inhibitor of several cytochrome P450 enzymes involved in the metabolism of other ASMs, contributing to boost their anticonvulsant efficacy as add-on therapy. These different MoAs involved in treatment of DS and recent data suggest a potential for STP to treat other neurological or non-neurological diseases.
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Affiliation(s)
- Alexandre Bacq
- Biocodex Research and Development Center, Compiègne, France.
| | - Antoine Depaulis
- Univ. Grenoble Alpes, Inserm, U1216, Grenoble Institut Neurosciences, Grenoble, France
| | | | | | - Elaine C Wirrell
- Divisions of Child and Adolescent Neurology and Epilepsy, Department of Neurology, Mayo Clinic, Rochester, MN, USA
| | - Marc Verleye
- Biocodex Research and Development Center, Compiègne, France
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10
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Miralles RM, Boscia AR, Kittur S, Vundela SR, Wengert ER, Patel MK. Parvalbumin Interneuron Impairment Leads to Synaptic Transmission Deficits and Seizures in SCN8A Epileptic Encephalopathy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.09.579511. [PMID: 38464208 PMCID: PMC10925130 DOI: 10.1101/2024.02.09.579511] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
SCN8A epileptic encephalopathy (EE) is a severe epilepsy syndrome resulting from de novo mutations in the voltage-gated sodium channel Na v 1.6, encoded by the gene SCN8A . Na v 1.6 is expressed in both excitatory and inhibitory neurons, yet previous studies have primarily focused on the impact SCN8A mutations have on excitatory neuron function, with limited studies on the importance of inhibitory interneurons to seizure onset and progression. Inhibitory interneurons are critical in balancing network excitability and are known to contribute to the pathophysiology of other epilepsies. Parvalbumin (PV) interneurons are the most prominent inhibitory neuron subtype in the brain, making up about 40% of inhibitory interneurons. Notably, PV interneurons express high levels of Na v 1.6. To assess the role of PV interneurons within SCN8A EE, we used two mouse models harboring patient-derived SCN8A gain-of-function mutations, Scn8a D/+ , where the SCN8A mutation N1768D is expressed globally, and Scn8a W/+ -PV, where the SCN8A mutation R1872W is selectively expressed in PV interneurons. Expression of the R1872W SCN8A mutation selectively in PV interneurons led to the development of spontaneous seizures in Scn8a W/+ -PV mice and seizure-induced death, decreasing survival compared to wild-type. Electrophysiology studies showed that PV interneurons in Scn8a D/+ and Scn8a W/+ -PV mice were susceptible to depolarization block, a state of action potential failure. Scn8a D/+ and Scn8a W/+ -PV interneurons also exhibited increased persistent sodium current, a hallmark of SCN8A gain-of-function mutations that contributes to depolarization block. Evaluation of synaptic connections between PV interneurons and pyramidal cells showed an increase in synaptic transmission failure at high frequencies (80-120Hz) as well as an increase in synaptic latency in Scn8a D/+ and Scn8a W/+ -PV interneurons. These data indicate a distinct impairment of synaptic transmission in SCN8A EE, potentially decreasing overall cortical network inhibition. Together, our novel findings indicate that failure of PV interneuron spiking via depolarization block along with frequency-dependent inhibitory synaptic impairment likely elicits an overall reduction in the inhibitory drive in SCN8A EE, leading to unchecked excitation and ultimately resulting in seizures and seizure-induced death.
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11
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Li RK, Li H, Tian MQ, Li Y, Luo S, Liang XY, Liu WH, Li BM, Shi XQ, Li J, Li B, Shu XM. Investigation of FRMPD4 variants associated with X-linked epilepsy. Seizure 2024; 116:45-50. [PMID: 37330374 DOI: 10.1016/j.seizure.2023.05.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 05/11/2023] [Accepted: 05/15/2023] [Indexed: 06/19/2023] Open
Abstract
BACKGROUND The etiology of unexplained epilepsy in most patients remains unclear. Variants of FRMPD4 are suggested to be associated with neurodevelopmental disorders. Therefore, we screened for disease-causing FRMPD4 variants in patients with epilepsy. METHODS Trios-based whole-exome sequencing was conducted on a cohort of 85 patients with unexplained epilepsy, their parents, and extended family members. Additional cases with FRMPD4 variants were identified from the China Epilepsy Gene Matching Platform V.1.0. The frequency of variants was analyzed, and their subregional effects were predicted using in silico tools. The genotype-phenotype correlation of the newly defined causative genes and protein stability were analyzed using I-Mutant V.3.0 and Grantham scores. RESULTS Two novel missense variants of FRMPD4 were identified in two families. Using the gene matching platform, we identified three additional novel missense variants. These variants presented at low or no allele frequencies in the gnomAD database. All the variants were located outside the three FRMPD4 main domains (WW, PDZ, and FERM). In silico analyses revealed that the variants were damaging and were predicted to be the least stable. All patients eventually became seizure-free. Eight of the 21 patients with FRMPD4 variants had epilepsy, of which five (63%) had missense variants located outside the domains, two had deletions involving exon 2, and one had a frameshift variant located outside the domains. Patients with epilepsy caused by missense variants were often free of intellectual disabilities (4/5), whereas patients with epilepsy caused by truncated variants had intellectual disabilities and structural brain abnormalities (3/3). CONCLUSIONS The FRMPD4 gene is potentially associated with epilepsy. The genotype-phenotype correlation of FRMPD4 variants indicated that differences in variant types and locations of FRMPD4 may explain their phenotypic variation.
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Affiliation(s)
- Ren-Ke Li
- Department of Pediatrics, Affiliated Hospital of Zunyi Medical University, Children's Hospital of Guizhou Province, Zunyi 563003, China
| | - Huan Li
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Mao-Qiang Tian
- Department of Pediatrics, Affiliated Hospital of Zunyi Medical University, Children's Hospital of Guizhou Province, Zunyi 563003, China
| | - Yun Li
- Department of Brain Function and Neuroelectrophysiology, the Affiliated Nanhua Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan 421002, China
| | - Sheng Luo
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Xiao-Yu Liang
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Wen-Hui Liu
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Bin-Mei Li
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China
| | - Xiao-Qi Shi
- Department of Pediatrics, Affiliated Hospital of Zunyi Medical University, Children's Hospital of Guizhou Province, Zunyi 563003, China
| | - Juan Li
- Department of Pediatrics, Affiliated Hospital of Zunyi Medical University, Children's Hospital of Guizhou Province, Zunyi 563003, China
| | - Bin Li
- Institute of Neuroscience and Department of Neurology of the Second Affiliated Hospital of Guangzhou Medical University, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou 510260, China.
| | - Xiao-Mei Shu
- Department of Pediatrics, Affiliated Hospital of Zunyi Medical University, Children's Hospital of Guizhou Province, Zunyi 563003, China.
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12
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Hammer M, Krzyzaniak C, Bahramnejad E, Smelser K, Hack J, Watkins J, Ronaldson P. Sex differences in physiological response to increased neuronal excitability in a knockin mouse model of pediatric epilepsy. Clin Sci (Lond) 2024; 138:205-223. [PMID: 38348743 PMCID: PMC10881277 DOI: 10.1042/cs20231572] [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: 11/29/2023] [Revised: 02/01/2024] [Accepted: 02/09/2024] [Indexed: 02/22/2024]
Abstract
BACKGROUND Epilepsy is a common neurological disease; however, few if any of the currently marketed antiseizure medications prevent or cure epilepsy. Discovery of pathological processes in the early stages of epileptogenesis has been challenging given the common use of preclinical models that induce seizures in physiologically normal animals. Moreover, despite known sex dimorphism in neurological diseases, females are rarely included in preclinical epilepsy models. METHODS We characterized sex differences in mice carrying a pathogenic knockin variant (p.N1768D) in the Scn8a gene that causes spontaneous tonic-clonic seizures (TCs) at ∼3 months of age and found that heterozygous females are more resilient than males in mortality and morbidity. To investigate the cellular mechanisms that underlie female resilience, we utilized blood-brain barrier (BBB) and hippocampal transcriptomic analyses in heterozygous mice before seizure onset (pre-TC) and in mice that experienced ∼20 TCs (post-TC). RESULTS In the pre-TC latent phase, both sexes exhibited leaky BBB; however, patterns of gene expression were sexually dimorphic. Females exhibited enhanced oxidative phosphorylation and protein biogenesis, while males activated gliosis and CREB signaling. After seizure onset (chronic phase), females exhibited a metabolic switch to lipid metabolism, while males exhibited increased gliosis and BBB dysfunction and a strong activation of neuroinflammatory pathways. CONCLUSION The results underscore the central role of oxidative stress and BBB permeability in the early stages of epileptogenesis, as well as sex dimorphism in response to increasing neuronal hyperexcitability. Our results also highlight the need to include both sexes in preclinical studies to effectively translate results of drug efficacy studies.
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Affiliation(s)
- Michael F. Hammer
- BIO5 Institute, University of Arizona, Tucson, Arizona, U.S.A
- Department of Neurology, University of Arizona, Tucson, Arizona, U.S.A
| | | | - Erfan Bahramnejad
- BIO5 Institute, University of Arizona, Tucson, Arizona, U.S.A
- Department of Pharmacology, University of Arizona, Tucson, Arizona, U.S.A
| | | | - Joshua B. Hack
- BIO5 Institute, University of Arizona, Tucson, Arizona, U.S.A
| | - Joseph C. Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, U.S.A
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13
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Zhao X, He Z, Li Y, Yang X, Li B. Atypical absence seizures and gene variants: A gene-based review of etiology, electro-clinical features, and associated epilepsy syndrome. Epilepsy Behav 2024; 151:109636. [PMID: 38232560 DOI: 10.1016/j.yebeh.2024.109636] [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: 11/08/2023] [Revised: 01/01/2024] [Accepted: 01/05/2024] [Indexed: 01/19/2024]
Abstract
Atypical absence seizures are generalized non-convulsive seizures that often occur in children with cognitive impairment. They are common in refractory epilepsy and have been recognized as one of the hallmarks of developmental epileptic encephalopathies. Notably, pathogenic variants associated with AAS, such as GABRG2, GABRG3, SLC6A1, CACNB4, SCN8A, and SYNGAP1, are also linked to developmental epileptic encephalopathies. Atypical absences differ from typical absences in that they are frequently drug-resistant and the prognosis is dependent on the etiology or related epileptic syndromes. To improve clinicians' understanding of atypical absences and provide novel perspectives for clinical treatment, we have reviewed the electro-clinical characteristics, etiologies, treatment, and prognosis of atypical absences, with a focus on the etiology of advancements in gene variants, shedding light on potential avenues for improved clinical management.
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Affiliation(s)
| | - Zimeng He
- Shandong University, Jinan, Shandong, China
| | - Yumei Li
- Shandong University, Jinan, Shandong, China
| | - Xiaofan Yang
- Shandong University, Jinan, Shandong, China; Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, China.
| | - Baomin Li
- Shandong University, Jinan, Shandong, China; Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, Shandong, China.
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14
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Hebbar M, Al-Taweel N, Gill I, Boelman C, Dean RA, Goodchild SJ, Mezeyova J, Shuart NG, Johnson JP, Lee J, Michoulas A, Huh LL, Armstrong L, Connolly MB, Demos MK. Expanding the genotype-phenotype spectrum in SCN8A-related disorders. BMC Neurol 2024; 24:31. [PMID: 38233770 PMCID: PMC10792783 DOI: 10.1186/s12883-023-03478-y] [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: 07/31/2023] [Accepted: 11/27/2023] [Indexed: 01/19/2024] Open
Abstract
BACKGROUND SCN8A-related disorders are a group of variable conditions caused by pathogenic variations in SCN8A. Online Mendelian Inheritance in Man (OMIM) terms them as developmental and epileptic encephalopathy 13, benign familial infantile seizures 5 or cognitive impairment with or without cerebellar ataxia. METHODS In this study, we describe clinical and genetic results on eight individuals from six families with SCN8A pathogenic variants identified via exome sequencing. RESULTS Clinical findings ranged from normal development with well-controlled epilepsy to significant developmental delay with treatment-resistant epilepsy. Three novel and three reported variants were observed in SCN8A. Electrophysiological analysis in transfected cells revealed a loss-of-function variant in Patient 4. CONCLUSIONS This work expands the clinical and genotypic spectrum of SCN8A-related disorders and provides electrophysiological results on a novel loss-of-function SCN8A variant.
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Affiliation(s)
- Malavika Hebbar
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Nawaf Al-Taweel
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Inderpal Gill
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Cyrus Boelman
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Richard A Dean
- Xenon Pharmaceuticals, 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| | - Samuel J Goodchild
- Xenon Pharmaceuticals, 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| | - Janette Mezeyova
- Xenon Pharmaceuticals, 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| | | | - J P Johnson
- Xenon Pharmaceuticals, 200-3650 Gilmore Way, Burnaby, BC, V5G 4W8, Canada
| | - James Lee
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Aspasia Michoulas
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Linda L Huh
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Linlea Armstrong
- Department of Medical Genetics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Mary B Connolly
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Michelle K Demos
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
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15
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Berg AT, Ludwig NN, Wojnaroski M, Chapman CAT, Hommer R, Conecker G, Hecker JZ, Downs J. FDA Patient-Focused Drug Development Guidances: Considerations for Trial Readiness in Rare Developmental and Epileptic Encephalopathies. Neurology 2024; 102:e207958. [PMID: 38165374 PMCID: PMC10834124 DOI: 10.1212/wnl.0000000000207958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Accepted: 09/11/2023] [Indexed: 01/03/2024] Open
Abstract
Developmental and epileptic encephalopathies (DEE) are rare, often monogenic neurodevelopmental conditions. Most affected individuals have refractory seizures. All have multiple severe impairments which can be as life-limiting as or more limiting than the seizures themselves. Mechanism- and gene-targeted therapies for these individually rare, genetic conditions hold hope for treatment, amelioration of disease expression, and even cure. The near absence of fit-for-purpose (FFP) clinical outcome assessments (COA) to establish the benefits for nonseizure outcomes of these new therapies in clinical trials poses significant challenges to drug development. The Food and Drug Administration Patient-Focused Drug Development guidance series provides direction for how to overcome these challenges and to ensure FFP measures are available for trials. The goal is to have measures that address outcomes of importance to patients and caregivers, reliably and accurately measure the outcome in the spectrum of abilities for the target disease, and are sensitive to meaningful change over time. The guidances identify 3 primary strategies: (1) directly adopting and implementing available outcome measures; (2) creating measures de novo; and (3) a middle path of adapting or modifying existing measures. Emphasized throughout the guidances is the indispensable and extensive role of the patient or caregiver to assuring the goal of having fit measures is achieved. This review specifically considers the difficulties of adopting available COAs in severely impaired patient groups and ways to adapt or modify existing COAs to be FFP as encouraged in the guidances. Adaptations include alternative scoring, use of assessments in out-of-intended age ranges, and modifications for individuals with sensory or motor impairments. Some additional considerations that may facilitate achieving adequate clinical outcome measures, especially for rare diseases, include use of personalized endpoints, merging of existing COAs, and developing a consortium of rare DEE advocates and researchers to ensure fitness of adapted COAs across multiple rare disease groups. The FDA guidances help ensure that clinical trials targeting nonseizure outcomes, especially in severely impaired populations, will have adequately valid and sensitive outcome measures. This in turn will strengthen the ability of trials to provide informative tests of whether treatments provide meaningful therapeutic efficacy.
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Affiliation(s)
- Anne T Berg
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
| | - Natasha N Ludwig
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
| | - Mary Wojnaroski
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
| | - Chere A T Chapman
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
| | - Rebecca Hommer
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
| | - Gabrielle Conecker
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
| | - JayEtta Z Hecker
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
| | - Jenny Downs
- From the Department of Neurology (A.T.B.), Northwestern-Feinberg School of Medicine, Chicago, IL; Decoding Developmental Epilepsies (A.T.B., G.C., J.Z.H.), Washington, DC; Department of Neuropsychology (N.N.L.), Kennedy Krieger Institute; Department of Psychiatry and Behavioral Sciences (N.N.L.), The Johns Hopkins School of Medicine, Baltimore, MD; Department of Psychology (M.W.), Nationwide Children's Hospital; Department of Pediatrics (M.W.), The Ohio State University, Columbus; Ardea Outcomes (C.A.T.C.), Halifax, Nova Scotia, Canada; Connections Beyond Sight and Sound Maryland & DC Deaf-Blind Project (R.H.), University of Maryland, College Park; The Inchstone Project (J.Z.H.); Telethon Kids Institute (J.D.), The University of Western Australia; and Curtin School of Allied Health (J.D.), Curtin University, Perth, Western Australia
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16
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Fang H, Hu W, Kang Q, Kuang X, Wang L, Zhang X, Liao H, Yang L, Yang H, Jiang Z, Wu L. Clinical characteristics and genetic analysis of pediatric patients with sodium channel gene mutation-related childhood epilepsy: a review of 94 patients. Front Neurol 2023; 14:1310419. [PMID: 38174099 PMCID: PMC10764033 DOI: 10.3389/fneur.2023.1310419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
Objective This study aimed to examine the clinical and gene-mutation characteristics of pediatric patients with sodium channel gene mutation-related childhood epilepsy and to provide a basis for precision treatment and genetic counseling. Methods The clinical data from 94 patients with sodium channel gene mutation-related childhood epilepsy who were treated at Hunan Children's Hospital from August 2012 to December 2022 were retrospectively evaluated, and the clinical characteristics, gene variants, treatment, and follow-up status were analyzed and summarized. Results Our 94 pediatric patients with sodium channel gene variant-related childhood epilepsy comprised 37 girls and 57 boys. The age of disease onset ranged from 1 day to 3 years. We observed seven different sodium channel gene variants, and 55, 14, 9, 6, 6, 2, and 2 patients had SCNlA, SCN2A, SCN8A, SCN9A, SCN1B, SCN11A, and SCN3A variants, respectively. We noted that 52 were reported variants and 42 were novel variants. Among all gene types, SCN1A, SCN2A, and SCN8A variants were associated with an earlier disease onset age. With the exception of the SCN1B, the other six genes were associated with clustering seizures. Except for variants SCN3A and SCN11A, some patients with other variants had status epilepticus (SE). The main diagnosis of children with SCN1A variants was Dravet syndrome (DS) (72.7%), whereas patients with SCN2A and SCN8A variants were mainly diagnosed with various types of epileptic encephalopathy, accounting for 85.7% (12 of 14) and 88.9% (8 of 9) respectively. A total of five cases of sudden unexpected death in epilepsy (SUDEP) occurred in patients with SCN1A, SCN2A, and SCN8A variants. The proportion of benign epilepsy in patients with SCN9A, SCN11A, and SCN1B variants was relatively high, and the epilepsy control rate was higher than the rate of other variant types. Conclusion Sodium channel gene variants involve different epileptic syndromes, and the treatment responses also vary. We herein reported 42 novel variants, and we are also the first ever to report two patients with SCN11A variants, thereby increasing the gene spectrum and phenotypic profile of sodium channel dysfunction. We provide a basis for precision treatment and prognostic assessment.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Liwen Wu
- Neurology Department, Hunan Children's Hospital, Changsha, China
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Chung KM, Hack J, Andrews J, Galindo-Kelly M, Schreiber J, Watkins J, Hammer MF. Clinical severity is correlated with age at seizure onset and biophysical properties of recurrent gain of function variants associated with SCN8A-related epilepsy. Epilepsia 2023; 64:3365-3376. [PMID: 37585367 DOI: 10.1111/epi.17747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 08/14/2023] [Accepted: 08/14/2023] [Indexed: 08/18/2023]
Abstract
OBJECTIVE Genetic variants in the SCN8A gene underlie a wide spectrum of neurodevelopmental phenotypes including several distinct seizure types and a host of comorbidities. One of the major challenges facing clinicians and researchers alike is to identify genotype-phenotype (G-P) correlations that may improve prognosis, guide treatment decisions, and lead to precision medicine approaches. METHODS We investigated G-P correlations among 270 participants harboring gain-of-function (GOF) variants enrolled in the International SCN8A Registry, a patient-driven online database. We performed correlation analyses stratifying the cohort by clinical phenotypes to identify diagnostic features that differ among patients with varying levels of clinical severity, and that differ among patients with distinct GOF variants. RESULTS Our analyses confirm positive correlations between age at seizure onset and developmental skills acquisition (developmental quotient), rate of seizure freedom, and percentage of cohort with developmental delays, and identify negative correlations with number of current and weaned antiseizure medications. This set of features is more detrimentally affected in individuals with a priori expectations of more severe clinical phenotypes. Our analyses also reveal a significant correlation between a severity index combining clinical features of individuals with a particular highly recurrent variant and an independent electrophysiological score assigned to each variant based on in vitro testing. SIGNIFICANCE This is one of the first studies to identify statistically significant G-P correlations for individual SCN8A variants with GOF properties. The results suggest that individual GOF variants (1) are predictive of clinical severity for individuals carrying those variants and (2) may underlie distinct clinical phenotypes of SCN8A disease, thus helping to explain the wide SCN8A-related epilepsy disease spectrum. These results also suggest that certain features present at initial diagnosis are predictive of clinical severity, and with more informed treatment plans, may serve to improve prognosis for patients with SCN8A GOF variants.
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Affiliation(s)
- Kyung Mi Chung
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
| | - Joshua Hack
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
| | - Jennifer Andrews
- Department of Pediatrics, University of Arizona, Tucson, Arizona, USA
| | | | - John Schreiber
- Department of Neurology, Children's National Medical Center, Washington, District of Columbia, USA
| | - Joseph Watkins
- Department of Mathematics, University of Arizona, Tucson, Arizona, USA
| | - Michael F Hammer
- BIO5 Institute, University of Arizona, Tucson, Arizona, USA
- Neurology Department, University of Arizona, Tucson, Arizona, USA
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Bahramnejad E, Barney ER, Lester S, Hurtado A, Thompson T, Watkins JC, Hammer MF. Greater female than male resilience to mortality and morbidity in the Scn8a mouse model of pediatric epilepsy. Int J Neurosci 2023:1-13. [PMID: 37929583 DOI: 10.1080/00207454.2023.2279497] [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: 12/28/2021] [Accepted: 10/31/2023] [Indexed: 11/07/2023]
Abstract
AIMS Females and males of all ages are affected by epilepsy; however, unlike many clinical studies, most preclinical research has focused on males. Genetic variants in the voltage-gated sodium channel gene, SCN8A, are associated with a broad spectrum of neurological and epileptic syndromes. Here we investigate sex differences in the natural history of the Scn8a-N1768D knockin mouse model of pediatric epilepsy. METHODS We utilize 24/7 video to monitor juveniles and adults of both sexes to investigate variability in seizure activity (e.g. onset and frequency), mortality and morbidity, response to cannabinoids, and mode of death. We also monitor sleep architecture using a noninvasive piezoelectric method in order to identify factors that influence seizure severity and outcome. RESULTS Both sexes had nearly 100% penetrance in seizure onset and early mortality. However, adult heterozygous (D/+) females were more resilient as exhibited by the ability to tolerate more seizures over a longer lifespan. Homozygous (D/D) juveniles did not exhibit a sex difference in overall survival. Female estrus cycle was disrupted before seizure onset, while sleep was disrupted in both sexes in association with seizure onset. Females typically died while in convulsive status epilepticus; however, a high proportion of males died while not experiencing behavioral seizures. Only juvenile and adult males benefited from cannabinoid administration. CONCLUSIONS These results support the hypothesis that factors associated with sexual differentiation play a role in the neurobiology of epilepsy and point to the importance of including both sexes in the design of studies to identify new epilepsy therapies.
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Affiliation(s)
- Erfan Bahramnejad
- Graduate Program in Pharmacology, University of Arizona, Tucson Arizona, AZ, USA
| | - Emily R Barney
- BIO5 Institute, University of Arizona, Tucson Arizona, AZ, USA
| | - Sarah Lester
- BIO5 Institute, University of Arizona, Tucson Arizona, AZ, USA
| | - Aurora Hurtado
- BIO5 Institute, University of Arizona, Tucson Arizona, AZ, USA
| | | | - Joseph C Watkins
- Department of Mathematics, University of Arizona, Tucson Arizona, AZ, USA
| | - Michael F Hammer
- BIO5 Institute, University of Arizona, Tucson Arizona, AZ, USA
- Department of Neurology, University of Arizona, Tucson Arizona, AZ, USA
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Marchesi VT. Impaired electrical activity of the brain explains the onset of dementia in aging people. FASEB J 2023; 37:e23249. [PMID: 37823210 DOI: 10.1096/fj.202301255rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/21/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
Aging brains that share many cognitive deficits with the early stages of Alzheimer's-type dementias are not caused by toxic protein deposits but by somatic mutations that impair synaptic signaling. These mutant proteins that contribute to neuronal action potentials could be biomarkers of functional defects that offer new approaches to diagnosis and treatment.
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Hebbar M, Al-Taweel N, Gill I, Boelman C, Dean RA, Goodchild SJ, Mezeyova J, Shuart NG, Johnson JP, Lee J, Michoulas A, Huh LL, Armstrong L, Connolly MB, Demos MK. Expanding the genotype-phenotype spectrum in SCN8A-related disorders. RESEARCH SQUARE 2023:rs.3.rs-3221902. [PMID: 37609289 PMCID: PMC10441468 DOI: 10.21203/rs.3.rs-3221902/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/24/2023]
Abstract
Background SCN8A-related disorders are a group of variable conditions caused by pathogenic variations in SCN8A. Online Mendelian Inheritance in Man (OMIM) terms them as developmental and epileptic encephalopathy 13, benign familial infantile seizures 5 or cognitive impairment with or without cerebellar ataxia. Methods In this study, we describe clinical and genetic results on eight individuals from six families with SCN8A pathogenic variants identified via exome sequencing. Results Clinical findings ranged from normal development with well-controlled epilepsy to significant developmental delay with treatment-resistant epilepsy. Three novel and three reported variants were observed in SCN8A. Electrophysiological analysis in transfected cells revealed a loss-of-function variant in Patient 4. Conclusions This work expands the clinical and genotypic spectrum of SCN8A-related disorders and provides electrophysiological results on a novel loss-of-function SCN8A variant.
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Affiliation(s)
- Malavika Hebbar
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Nawaf Al-Taweel
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Inderpal Gill
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Cyrus Boelman
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Richard A Dean
- Xenon Pharmaceuticals, 200-3650 Gilmore Way, Burnaby, BC V5G 4W8
| | | | - Janette Mezeyova
- Xenon Pharmaceuticals, 200-3650 Gilmore Way, Burnaby, BC V5G 4W8
| | | | - J P Johnson
- Xenon Pharmaceuticals, 200-3650 Gilmore Way, Burnaby, BC V5G 4W8
| | - James Lee
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Aspasia Michoulas
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Linda L Huh
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Linlea Armstrong
- Department of Medical Genetics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Mary B Connolly
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
| | - Michelle K Demos
- Division of Neurology, Department of Pediatrics, BC Children's Hospital, Faculty of Medicine, University of British Columbia, Vancouver BC
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Miao P, Zhu X, Jin W, Yu L, Li Y, Wang Y, Su Q, Xu S, Wang S, Feng J. Efficacy of perampanel in pediatric epilepsy with known and presumed genetic etiology. Ann Clin Transl Neurol 2023; 10:1374-1382. [PMID: 37329172 PMCID: PMC10424658 DOI: 10.1002/acn3.51828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 05/17/2023] [Accepted: 06/03/2023] [Indexed: 06/18/2023] Open
Abstract
OBJECTIVE The efficacy of perampanel (PER) in pediatric epilepsy with specific etiologies has not been well established. Here, we investigated outcome and predictors of PER treatment in a pediatric cohort with known and presumed genetic etiology. METHODS We included pediatric patients with potential genetic epilepsy who received PER treatment and underwent whole-exome sequencing (WES) from January 2020 to September 2021. All patients were followed up for >12 months. RESULTS A total of 124 patients were included. Overall response rates were 51.6% and 49.6% at 6 months and 12 months, respectively. Pathogenic or likely pathogenic variants in 27 multiple genes were detected among 58 patients (46.8%) by WES. On performing multivariate logistic regression analysis, only developmental delay (OR = 0.406, P = 0.042) was a negative predictor of treatment response. However, the seizure onset age, positive WES results, and number of ASMs before PER administration were not significantly. Thirteen carriers with variants in the SCN1A gene showed a better response compared to eight patients with other sodium channels (P = 0.007), and to the other 45 patients with positive WES results (OR = 7.124, 95% CI = 1.306-38.860, P = 0.023). Adverse events were only reported in 23 patients, the most common being emotional problems. INTERPRETATION PER is safe and efficacious in pediatric patients with known and presumed genetic etiology. The response rate is comparable to that reported in other pediatric populations, and lower among those with developmental delay. A gene-specific response to PER is found along with better efficacy links to pathogenic variants in the SCN1A gene.
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Affiliation(s)
- Pu Miao
- Department of PediatricsSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou310009China
| | - Xueying Zhu
- Department of PediatricsJinhua Lanxi People's HospitalJinhuaZhejiang321000China
| | - Wenqin Jin
- Department of PediatricsSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou310009China
| | - Lingyan Yu
- Department of PharmacySecond Affiliated Hospital, Zhejiang University School of MedicineHangzhouChina
| | - Yanfang Li
- Department of PediatricsSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou310009China
| | - Ye Wang
- Department of PediatricsSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou310009China
| | - Qunyan Su
- Department of PediatricsTaizhou Woman and Children's HospitalTaizhou318000China
| | - Sha Xu
- Department of Neurology, Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou310009China
| | - Shuang Wang
- Department of Neurology, Epilepsy CenterSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou310009China
| | - Jianhua Feng
- Department of PediatricsSecond Affiliated Hospital, School of Medicine, Zhejiang UniversityHangzhou310009China
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22
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Barbieri R, Nizzari M, Zanardi I, Pusch M, Gavazzo P. Voltage-Gated Sodium Channel Dysfunctions in Neurological Disorders. Life (Basel) 2023; 13:life13051191. [PMID: 37240836 DOI: 10.3390/life13051191] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/12/2023] [Accepted: 05/14/2023] [Indexed: 05/28/2023] Open
Abstract
The pore-forming subunits (α subunits) of voltage-gated sodium channels (VGSC) are encoded in humans by a family of nine highly conserved genes. Among them, SCN1A, SCN2A, SCN3A, and SCN8A are primarily expressed in the central nervous system. The encoded proteins Nav1.1, Nav1.2, Nav1.3, and Nav1.6, respectively, are important players in the initiation and propagation of action potentials and in turn of the neural network activity. In the context of neurological diseases, mutations in the genes encoding Nav1.1, 1.2, 1.3 and 1.6 are responsible for many forms of genetic epilepsy and for Nav1.1 also of hemiplegic migraine. Several pharmacological therapeutic approaches targeting these channels are used or are under study. Mutations of genes encoding VGSCs are also involved in autism and in different types of even severe intellectual disability (ID). It is conceivable that in these conditions their dysfunction could indirectly cause a certain level of neurodegenerative processes; however, so far, these mechanisms have not been deeply investigated. Conversely, VGSCs seem to have a modulatory role in the most common neurodegenerative diseases such as Alzheimer's, where SCN8A expression has been shown to be negatively correlated with disease severity.
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Affiliation(s)
| | - Mario Nizzari
- Institute of Biophysics, Via de Marini 6, 16149 Genova, Italy
| | - Ilaria Zanardi
- Institute of Biophysics, Via de Marini 6, 16149 Genova, Italy
| | - Michael Pusch
- Institute of Biophysics, Via de Marini 6, 16149 Genova, Italy
| | - Paola Gavazzo
- Institute of Biophysics, Via de Marini 6, 16149 Genova, Italy
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Lee J, Kim YO, Lim BC, Lee J. PRRT2-positive self-limited infantile epilepsy: Initial seizure characteristics and response to sodium channel blockers. Epilepsia Open 2023. [PMID: 36775847 DOI: 10.1002/epi4.12708] [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: 10/27/2022] [Accepted: 02/04/2023] [Indexed: 02/14/2023] Open
Abstract
OBJECTIVE Self-limited infantile epilepsy (SeLIE) has distinctive clinical features, and the PRRT2 gene is known to be a considerable genetic cause. There have been a few studies on PRRT2-positive SeLIE only, and anti-seizure medications are often required due to frequent seizures at initial seizure onset. This study aimed to provide clinical information for the early recognition of patients with PRRT2-positive SeLIE and to propose effective anti-seizure medications for seizure control. METHODS We retrospectively reviewed 36 patients diagnosed with SeLIE with genetically confirmed pathogenic variants of PRRT2. In addition, six atypical cases with neonatal-onset seizures and unremitting after 3 years of age were included to understand the expanded clinical spectrum of PRRT2-related epilepsy. We analyzed the initial presentation, clinical course, and seizure control response to anti-seizure medications. RESULTS Patients with PRRT2-related epilepsy had characteristic seizure semiology at the initial presentation, including all afebrile, clustered (n = 23, 63.9%), short-duration (n = 33, 91.7%), and bilateral tonic-clonic seizures (n = 26, 72.2%). Genetic analysis revealed that c. 649dupC was the most common variant, and six patients had a 16p11.2 microdeletion containing the PRRT2 gene. One-third of the patients were sporadic cases without a family history of epilepsy or paroxysmal movement disorders. In the 33 patients treated with anti-seizure medications, sodium channel blockers, such as carbamazepine, were the most effective in seizure control. SIGNIFICANCE Our results delineated the clinical characteristics of PRRT2-positive SeLIE, differentiating it from other genetic infantile epilepsies and discovered the effective anti-seizure medications for initial clustered seizure control. If afebrile bilateral tonic-clonic seizures develop in a normally developed infant as a clustered pattern, PRRT2-positive SeLIE should be considered as a possible diagnosis, and sodium channel blockers should be administered as the first medication for seizure control.
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Affiliation(s)
- Jiwon Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
| | - Young Ok Kim
- Department of Pediatrics, Chonnam National University Medical School, Gwangju, South Korea
| | - Byung Chan Lim
- Department of Pediatrics, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Jeehun Lee
- Department of Pediatrics, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, South Korea
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Liu HF, Yuan TY, Yang JW, Li F, Wang F, Fu HM. A novel de novo heterozygous variant of the KCNQ2 gene: Contribution to early‑onset epileptic encephalopathy in a female infant. Mol Med Rep 2022; 26:282. [PMID: 35856407 PMCID: PMC9364154 DOI: 10.3892/mmr.2022.12797] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2021] [Accepted: 06/29/2022] [Indexed: 11/16/2022] Open
Abstract
Early-onset epileptic encephalopathy (EOEE) represents one of the most severe epilepsies, characterized by recurrent seizures during early infancy, electroencephalogram (EEG) abnormalities and varying degrees of neurodevelopmental delay. The KCNQ2 gene has been reported to have a major role in EOEE. In the present study, a 3-month-old female infant from the Chinese Lisu minority with EOEE was analyzed. Detailed clinical evaluations and next-generation sequencing were performed to investigate the clinical and genetic characteristics of this patient, respectively. Furthermore, the three-dimensional structure of the mutant protein was predicted by SWISS-Model and the expression of KCNQ2 protein in the patient was assessed by flow cytometry. It was observed that the patient presented with typical clinical features of EOEE, including repeated non-febrile seizures and significant EEG abnormalities. A novel heterozygous missense variant c.431G>C (p.R144P) in KCNQ2 was identified in the patient and the genotyping of KCNQ2 in the patient's parents suggested that this variant was de novo. Subsequently, the breakage of hydrogen bonds between certain amino acids was predicted by structural analysis of the mutant protein. Flow cytometric analysis detected a significant reduction buts not complete loss of native KCNQ2 protein expression in the patient (25.1%). In conclusion, a novel variant in KCNQ2 was confirmed as the genetic cause for EOEE in this patient. The present study expanded the pathogenic mutation spectrum of KCNQ2, enhanced the understanding of the molecular pathogenesis of EOEE and provided novel clues for research on the genotype-phenotype correlation in this disease.
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Affiliation(s)
- Hai-Feng Liu
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Ting-Yun Yuan
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Jia-Wu Yang
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Feng Li
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Fan Wang
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
| | - Hong-Min Fu
- Department of Pulmonary and Critical Care Medicine, Kunming Children's Hospital and Yunnan Key Laboratory of Children's Major Disease Research, Kunming, Yunnan 650034, P.R. China
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Podkorytova I, Hays R, Perven G, Alick Lindstrom S. Epilepsy surgery in patient with monogenic epilepsy related to SCN8A mutation. Epilepsy Behav Rep 2022; 18:100536. [PMID: 35492509 PMCID: PMC9038545 DOI: 10.1016/j.ebr.2022.100536] [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: 01/31/2022] [Revised: 03/14/2022] [Accepted: 03/18/2022] [Indexed: 11/05/2022] Open
Abstract
This is the first epilepsy surgery report in patient with SCN8A mutation. Stereo-EEG evaluation localized seizure onset to the right hippocampus. Resection led to 1.5-year seizure freedom, then seizures relapsed. Seizure frequency after relapse was significantly lower than preoperatively. Epilepsy surgery reduced seizure burden in patient with SCN8A-related epilepsy.
Epilepsy surgery is superior to prolonged medical therapy in patients with drug-resistant focal epilepsy, but reports on epilepsy surgery outcomes for patients with a genetic etiology are limited, especially in adults. This is the first documented report of a stereoelectroencephalography (SEEG) evaluation and resective surgery outcome in an adult patient with epilepsy related to SCN8A mutation. We describe a patient with epilepsy related to SCN8A mutation which was reported as a variant of uncertain significance at time of his pre-surgical evaluation and reclassified as likely pathogenic about 3 years after resective epilepsy surgery. Most of his pre-surgical evaluation results suggested right temporal lobe epilepsy, but few reported semiological symptoms, ictal SPECT, and neuropsychology results were discordant, and brain MRI was non-lesional. Therefore, SEEG was recommended; ultimately, seizures were localized to the right hippocampus. He was seizure-free for 1.5 years after right anterior temporal lobectomy, then reported three focal to bilateral tonic-clonic (FBTC) seizures in the subsequent 12 months (preoperatively, 6 focal impaired awareness seizures and 4–6 FBTC per year). This case demonstrates that epilepsy surgery reduced seizure burden in a patient with SCN8A-related epilepsy granting him short-term seizure freedom after resection, and then decreased seizure frequency after relapse compared to the preoperative baseline.
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Nevin SM, Wakefield CE, Dadich A, LeMarne F, Macintosh R, Beavis E, Sachdev R, Bye A, Nunn K, Palmer EE. Hearing parents' voices: A priority-setting workshop to inform a suite of psychological resources for parents of children with rare genetic epilepsies. PEC INNOVATION 2021; 1:100014. [PMCID: PMC10194388 DOI: 10.1016/j.pecinn.2021.100014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 12/07/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Objective To understand parents' of children with developmental and epileptic encephalopathies needs and preferences for psychological resources. Methods Using a person-based approach, a multidisciplinary panel of clinician and researchers (n = 9) hosted a priority-setting workshop to 1) understand parents' needs and preferences for psychological resources and 2) to develop ‘guiding principles’ to inform a future suite of psychological resources. The multidisciplinary panel analysed the parent priority-setting workshop data, using a combination of thematic and lexical analysis. Results Thematic analysis identified six key domains wherein parents (n = 8) prioritised a need for psychological resources to support adaptation to their child's genetic DEE diagnosis. Lexical analysis revealed that connection to diagnosis-specific resources provided a pathway to promote enhanced psychological adaptation, by reducing social isolation and reorienting parents towards feelings of hope. Combination of both analyses generated six thematic informed ‘guiding principles’. Conclusion Codesigned psychological resources may help parents to cope with the unique and complex interplay of stressors associated with their child's DEE diagnosis and treatment. Our ‘guiding principles’ will be translated to inform a future suite of tailored psychological resources. Innovation This study demonstrates an innovative codesign approach to inform tailored psychological resources for families of children with rare genetic conditions. There is a deficit of research exploring the psychological impacts of parenting children with genetic DEEs. Tailored and codesigned psychological resources are essential due to the complexity and uniqueness of genetic DEEs. We collaborated with parents to codesign the content and scope of a future suite of person-based psychological resources. Thematic and lexical analyses combined identified that person-based resources reduced parent isolation and promoted hope. Insights generated from this study will be applied to inform psychological resources tailored for rare disease families.
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Affiliation(s)
- Suzanne M. Nevin
- School of Women's and Children's Health, UNSW Medicine and Health, UNSW Sydney, Australia
- Behavioural Sciences Unit, Kids Cancer Centre, Sydney Children's Hospital, Randwick, Australia
| | - Claire E. Wakefield
- School of Women's and Children's Health, UNSW Medicine and Health, UNSW Sydney, Australia
- Behavioural Sciences Unit, Kids Cancer Centre, Sydney Children's Hospital, Randwick, Australia
| | - Ann Dadich
- School of Business, Western Sydney University, Locked Bag 1797, Penrith, NSW 2751, Australia
| | - Fleur LeMarne
- School of Women's and Children's Health, UNSW Medicine and Health, UNSW Sydney, Australia
- Department of Neurology, Sydney Children's Hospital, Randwick, Australia
| | - Rebecca Macintosh
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, Australia
| | - Erin Beavis
- Department of Neurology, Sydney Children's Hospital, Randwick, Australia
| | - Rani Sachdev
- School of Women's and Children's Health, UNSW Medicine and Health, UNSW Sydney, Australia
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, Australia
| | - Ann Bye
- School of Women's and Children's Health, UNSW Medicine and Health, UNSW Sydney, Australia
- Department of Neurology, Sydney Children's Hospital, Randwick, Australia
| | - Kenneth Nunn
- Department of Psychological Medicine, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Elizabeth E. Palmer
- School of Women's and Children's Health, UNSW Medicine and Health, UNSW Sydney, Australia
- Centre for Clinical Genetics, Sydney Children's Hospital, Randwick, Australia
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