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Martins Custodio H, Clayton LM, Bellampalli R, Pagni S, Silvennoinen K, Caswell R, Brunklaus A, Guerrini R, Koeleman BPC, Lemke JR, Møller RS, Scheffer IE, Weckhuysen S, Zara F, Zuberi S, Kuchenbaecker K, Balestrini S, Mills JD, Sisodiya SM. Widespread genomic influences on phenotype in Dravet syndrome, a 'monogenic' condition. Brain 2023; 146:3885-3897. [PMID: 37006128 PMCID: PMC10473570 DOI: 10.1093/brain/awad111] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 02/01/2023] [Accepted: 03/12/2023] [Indexed: 04/04/2023] Open
Abstract
Dravet syndrome is an archetypal rare severe epilepsy, considered 'monogenic', typically caused by loss-of-function SCN1A variants. Despite a recognizable core phenotype, its marked phenotypic heterogeneity is incompletely explained by differences in the causal SCN1A variant or clinical factors. In 34 adults with SCN1A-related Dravet syndrome, we show additional genomic variation beyond SCN1A contributes to phenotype and its diversity, with an excess of rare variants in epilepsy-related genes as a set and examples of blended phenotypes, including one individual with an ultra-rare DEPDC5 variant and focal cortical dysplasia. The polygenic risk score for intelligence was lower, and for longevity, higher, in Dravet syndrome than in epilepsy controls. The causal, major-effect, SCN1A variant may need to act against a broadly compromised genomic background to generate the full Dravet syndrome phenotype, whilst genomic resilience may help to ameliorate the risk of premature mortality in adult Dravet syndrome survivors.
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Affiliation(s)
- Helena Martins Custodio
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
| | - Lisa M Clayton
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
| | - Ravishankara Bellampalli
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
| | - Susanna Pagni
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
| | - Katri Silvennoinen
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
- Kuopio Epilepsy Center, Neurocenter, Kuopio University Hospital, Kuopio 70210, Finland
| | - Richard Caswell
- Exeter Genomics Laboratory, Royal Devon University Healthcare NHS Foundation Trust, Exeter EX2 5DW, UK
| | - Andreas Brunklaus
- Paediatric Neuroscience Research Group, Royal Hospital for Children, Glasgow G51 4TF, UK
- Institute of Health and Wellbeing, University of Glasgow, Glasgow G12 8TB, UK
| | - Renzo Guerrini
- Neuroscience Department, Meyer Children’s Hospital IRCSS, University of Florence, 50139 Florence, Italy
| | - Bobby P C Koeleman
- Department of Genetics, University Medical Centre Utrecht, 3584CX Utrecht, The Netherlands
| | - Johannes R Lemke
- Institute of Human Genetics, University of Leipzig Medical Center, Leipzig 04103, Germany
- Center for Rare Diseases, University of Leipzig Medical Center, Leipzig 04103, Germany
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, Danish Epilepsy Centre, DK-4293 Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, DK-5230 Odense, Denmark
| | - Ingrid E Scheffer
- Epilepsy Research Centre, Florey Institute, University of Melbourne, Austin Health and Royal Children's Hospital, Melbourne, VIC 3084, Australia
- Murdoch Children's Research Institute, Parkville, VIC 3052, Australia
| | - Sarah Weckhuysen
- Applied and Translational Neurogenomics Group, VIB Centre for Molecular Neurology, VIB, Antwerp 2610, Belgium
- Translational Neurosciences, Faculty of Medicine and Health Science, University of Antwerp, Antwerp 2650, Belgium
- Department of Neurology, University Hospital Antwerp, Antwerp 2650, Belgium
- µNEURO Research Centre of Excellence, University of Antwerp, Antwerp 2610, Belgium
| | - Federico Zara
- Unit of Medical Genetics, IRCCS Istituto Giannina Gaslini, 16147 Genoa, Italy
- Department of Neurosciences Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, 16132 Genoa, Italy
| | - Sameer Zuberi
- Paediatric Neuroscience Research Group, Royal Hospital for Children, Glasgow G51 4TF, UK
- Institute of Health and Wellbeing, University of Glasgow, Glasgow G12 8TB, UK
| | | | - Simona Balestrini
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
- Neuroscience Department, Meyer Children’s Hospital IRCSS, University of Florence, 50139 Florence, Italy
| | - James D Mills
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
- Amsterdam UMC, University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, 1105 AZ Amsterdam, The Netherlands
| | - Sanjay M Sisodiya
- University College London Queen Square Institute of Neurology, Department of Clinical and Experimental Epilepsy, London, WC1N 3BG, UK
- Chalfont Centre for Epilepsy, Chalfont St Peter SL9 0RJ, UK
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Sullo F, Pasquetti E, Patanè F, Lo Bianco M, Marino SD, Polizzi A, Falsaperla R, Ruggieri M, Zanghì A, Praticò AD. SCN1A and Its Related Epileptic Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractEpilepsy is one of the most common neurological disorders, with a lifetime incidence of 1 in 26. Approximately two-thirds of epilepsy has a substantial genetic component in its etiology. As a result, simultaneous screening for mutations in multiple genes and performing whole exome sequencing (WES) are becoming very frequent in the clinical evaluation of children with epilepsy. In this setting, mutations in voltage-gated sodium channel (SCN) α-subunit genes are the most commonly identified cause of epilepsy, with sodium channel genes (i.e., SCN1A, SCN2A, SCN8A) being the most frequently identified causative genes. SCN1A mutations result in a wide spectrum of epilepsy phenotypes ranging from simple febrile seizures to Dravet syndrome, a severe epileptic encephalopathy. In case of mutation of SCN1A, it is also possible to observe behavioral alterations, such as impulsivity, inattentiveness, and distractibility, which can be framed in an attention deficit hyperactivity disorder (ADHD) like phenotype. Despite more than 1,200 SCN1A mutations being reported, it is not possible to assess a clear phenotype–genotype correlations. Treatment remains a challenge and seizure control is often partial and transitory.
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Affiliation(s)
- Federica Sullo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Elisa Pasquetti
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Francesca Patanè
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Manuela Lo Bianco
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Simona D. Marino
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intensive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Martino Ruggieri
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Antonio Zanghì
- Department of Medical and Surgical Sciences and Advanced Technology “G.F. Ingrassia,” University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Unit of Rare Diseases of the Nervous System in Childhood, Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, University of Catania, Catania, Italy
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Multicenter prospective longitudinal study in 34 patients with Dravet syndrome: Neuropsychological development in the first six years of life. Brain Dev 2021; 43:419-430. [PMID: 33478845 DOI: 10.1016/j.braindev.2020.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/26/2018] [Revised: 09/27/2020] [Accepted: 10/12/2020] [Indexed: 11/20/2022]
Abstract
The objective of this study was to identify developmental trajectories of developmental/behavioral phenotypes and possibly their relationship to epilepsy and genotype by analyzing developmental and behavioral features collected prospectively and longitudinally in a cohort of patients with Dravet syndrome (DS). Thirty-four patients from seven Italian tertiary pediatric neurology centers were enrolled in the study. All patients were examined for the SCN1A gene mutation and prospectively assessed from the first years of life with repeated full clinical observations including neurological and developmental examinations. Subjects were found to follow three neurodevelopmental trajectories. In the first group (16 patients), an initial and usually mild decline was observed between the second and the third year of life, specifically concerning visuomotor abilities, later progressing towards global involvement of all abilities. The second group (12 patients) showed an earlier onset of global developmental impairment, progressing towards a generally worse outcome. The third group of only two patients ended up with a normal neurodevelopmental quotient, but with behavioral and linguistic problems. The remaining four patients were not classifiable due to a lack of critical assessments just before developmental decline. The neurodevelopmental trajectories described in this study suggest a differential contribution of neurobiological and genetic factors. The profile of the first group, which included the largest fraction of patients, suggests that in the initial phase of the disease, visuomotor defects might play a major role in determining developmental decline. Early diagnosis of milder cases with initial visuomotor impairment may therefore provide new tools for a more accurate habilitation strategy.
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Menezes LFS, Sabiá Júnior EF, Tibery DV, Carneiro LDA, Schwartz EF. Epilepsy-Related Voltage-Gated Sodium Channelopathies: A Review. Front Pharmacol 2020; 11:1276. [PMID: 33013363 PMCID: PMC7461817 DOI: 10.3389/fphar.2020.01276] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 07/31/2020] [Indexed: 12/29/2022] Open
Abstract
Epilepsy is a disease characterized by abnormal brain activity and a predisposition to generate epileptic seizures, leading to neurobiological, cognitive, psychological, social, and economic impacts for the patient. There are several known causes for epilepsy; one of them is the malfunction of ion channels, resulting from mutations. Voltage-gated sodium channels (NaV) play an essential role in the generation and propagation of action potential, and malfunction caused by mutations can induce irregular neuronal activity. That said, several genetic variations in NaV channels have been described and associated with epilepsy. These mutations can affect channel kinetics, modifying channel activation, inactivation, recovery from inactivation, and/or the current window. Among the NaV subtypes related to epilepsy, NaV1.1 is doubtless the most relevant, with more than 1500 mutations described. Truncation and missense mutations are the most observed alterations. In addition, several studies have already related mutated NaV channels with the electrophysiological functioning of the channel, aiming to correlate with the epilepsy phenotype. The present review provides an overview of studies on epilepsy-associated mutated human NaV1.1, NaV1.2, NaV1.3, NaV1.6, and NaV1.7.
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Affiliation(s)
- Luis Felipe Santos Menezes
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Elias Ferreira Sabiá Júnior
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Diogo Vieira Tibery
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
| | - Lilian Dos Anjos Carneiro
- Faculdade de Medicina, Centro Universitário Euro Americano, Brasília, Brazil.,Faculdade de Medicina, Centro Universitário do Planalto Central, Brasília, Brazil
| | - Elisabeth Ferroni Schwartz
- Laboratório de Neurofarmacologia, Departamento de Ciências Fisiológicas, Universidade de Brasília, Brasília, Brazil
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Darra F, Battaglia D, Dravet C, Patrini M, Offredi F, Chieffo D, Piazza E, Fontana E, Olivieri G, Turrini I, Dalla Bernardina B, Granata T, Ragona F. Dravet syndrome: Early electroclinical findings and long-term outcome in adolescents and adults. Epilepsia 2020; 60 Suppl 3:S49-S58. [PMID: 31904122 DOI: 10.1111/epi.16297] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 07/01/2019] [Indexed: 01/15/2023]
Abstract
To describe the outcome of Dravet syndrome (DS) in adolescents and adults we conducted a longitudinal retrospective study of two independent cohorts of 34 adolescents (group 1) and 50 adults (group 2). In both cohorts, we collected information about genetic mutation, and semiology of seizures at onset and during disease course. At the last evaluation, we considered the following features: epilepsy (distinguishing myoclonic/complete and nonmyoclonic/incomplete phenotype), neurologic signs, intellectual disability (ID), and behavioral disorders. Moreover, in both cohorts, we performed a correlation analysis between early characteristics of the disease and the outcome of DS with regard to seizure persistence, ID, behavioral disorder, and neurologic impairment at last evaluation. Group 1 includes 22 adolescents with complete form of DS and 12 with incomplete form; group 2 includes 35 adults with complete form and 15 with incomplete form. The seizures persisted in 73.6% of adolescents and in 80% of adults, but epilepsy severity progressively decreased through age. Seizure persistence correlated with the complete phenotype and with the occurrence of reflex seizures. At last evaluation, ID was moderate or severe in 70.5% of adolescents and in 80% of adults. The most severe cognitive and motor impairment was observed in patients with persisting seizures. The severity of cognition, language, and neurologic impairment at last evaluation correlated statistically with the complete phenotype. The study confirms that the global outcome of DS is poor in most cases, albeit epilepsy severity decreases throughout adulthood. The improvement of epilepsy throughout ages is not associated with improvement in intellectual abilities and motor skills; this confirms that the unfavorable outcome is not a pure consequence of epilepsy.
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Affiliation(s)
- Francesca Darra
- Child Neuropsychiatry, Department of Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy
| | | | - Charlotte Dravet
- Child Neurology and Psychiatry, Catholic University Rome, Rome, Italy
| | - Mara Patrini
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, member of ERN EpiCare, Milan, Italy
| | - Francesca Offredi
- Child Neuropsychiatry, Department of Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy
| | - Daniela Chieffo
- Child Neurology and Psychiatry, Catholic University Rome, Rome, Italy.,Psychology Unit, Child Neurology and Psychiatry, Catholic University Rome, Rome, Italy
| | - Elena Piazza
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, member of ERN EpiCare, Milan, Italy
| | - Elena Fontana
- Unit Child Neuropsychiatry, Department of Maternal and Child, University Hospital of Verona, Verona, Italy
| | - Giorgia Olivieri
- Child Neurology and Psychiatry, Catholic University Rome, Rome, Italy.,Division of Metabolism, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Ida Turrini
- Child Neurology and Psychiatry, Catholic University Rome, Rome, Italy
| | - Bernardo Dalla Bernardina
- Child Neuropsychiatry, Department of Surgical Sciences, Dentistry, Gynecology and Pediatrics, University of Verona, Verona, Italy.,Research Center for Pediatric Epilepsies Verona, Verona, Italy
| | - Tiziana Granata
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, member of ERN EpiCare, Milan, Italy
| | - Francesca Ragona
- Department of Pediatric Neuroscience, Fondazione IRCCS Istituto Neurologico Carlo Besta, member of ERN EpiCare, Milan, Italy
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Cuddy LL, Sikka R, Silveira K, Bai S, Vanstone A. Music-evoked autobiographical memories (MEAMs) in Alzheimer disease: Evidence for a positivity effect. COGENT PSYCHOLOGY 2017. [DOI: 10.1080/23311908.2016.1277578] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Lola L. Cuddy
- Department of Psychology, Queen’s University, 62 Arch Street, Humphrey Hall, Room 232, Kingston, Ontario, Canada
| | - Ritu Sikka
- Department of Psychology, Queen’s University, 62 Arch Street, Humphrey Hall, Room 232, Kingston, Ontario, Canada
| | - Kristen Silveira
- Department of Psychology, Queen’s University, 62 Arch Street, Humphrey Hall, Room 232, Kingston, Ontario, Canada
| | - Sean Bai
- Department of Psychology, Queen’s University, 62 Arch Street, Humphrey Hall, Room 232, Kingston, Ontario, Canada
| | - Ashley Vanstone
- Department of Psychology, Queen’s University, 62 Arch Street, Humphrey Hall, Room 232, Kingston, Ontario, Canada
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7
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Battaglia D, Ricci D, Chieffo D, Guzzetta F. Outlining a core neuropsychological phenotype for Dravet syndrome. Epilepsy Res 2016; 120:91-7. [DOI: 10.1016/j.eplepsyres.2015.11.020] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 11/15/2015] [Accepted: 11/27/2015] [Indexed: 11/16/2022]
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From focal epilepsy to Dravet syndrome--Heterogeneity of the phenotype due to SCN1A mutations of the p.Arg1596 amino acid residue in the Nav1.1 subunit. Neurol Neurochir Pol 2015; 49:258-66. [PMID: 26188943 DOI: 10.1016/j.pjnns.2015.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 05/28/2015] [Accepted: 06/11/2015] [Indexed: 11/20/2022]
Abstract
OBJECTIVE The aim of this study was to analyze the intra-/interfamilial phenotypic heterogeneity due to variants at the highly evolutionary conservative p.Arg1596 residue in the Nav1.1 subunit. MATERIALS/PARTICIPANTS Among patients referred for analysis of the SCN1A gene one recurrent, heritable mutation was found in families enrolled into the study. Probands from those families even clinically diagnosed with atypical Dravet syndrome (DS), generalized epilepsy with febrile seizures plus (GEFS+), and focal epilepsy, had heterozygous p.Arg1596 His/Cys missense substitutions, c.4787G>T and c.4786C>T in the SCN1A gene. METHOD Full clinical evaluation, including cognitive development, neurological examination, EEGs, MRI was performed in probands and affected family members in developmental age. The whole SCN1A gene sequencing was performed for all probands. The exon 25, where the identified missense substitutions are localized, was directly analyzed for the other family members. RESULTS Mutation of the SCN1A p.1596Arg was identified in three families, in one case substitution p.Arg1596Cys and in two cases p.Arg1596His. Both mutations were previously described as pathogenic and causative for DS, GEFS+ and focal epilepsy. Spectrum of phenotypes among presented families with p.Arg1596 mutations shows heterogeneity ranged from asymptomatic cases, through FS and FS+ to GEFS+/Panayiotopoulos syndrome and epilepsies with and without febrile seizures, and epileptic encephalopathy such as DS. Phenotypes differ among patients displaying both focal and generalized epilepsies. Some patients demonstrated additionally Asperger syndrome and ataxia. CONCLUSION Clinical picture heterogeneity of the patients carrying mutation of the same residue indicates the involvement of the other factors influencing the SCN1A gene mutations' penetrance.
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Rubinstein M, Westenbroek RE, Yu FH, Jones CJ, Scheuer T, Catterall WA. Genetic background modulates impaired excitability of inhibitory neurons in a mouse model of Dravet syndrome. Neurobiol Dis 2014; 73:106-17. [PMID: 25281316 DOI: 10.1016/j.nbd.2014.09.017] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 09/04/2014] [Accepted: 09/24/2014] [Indexed: 01/23/2023] Open
Abstract
Dominant loss-of-function mutations in voltage-gated sodium channel NaV1.1 cause Dravet Syndrome, an intractable childhood-onset epilepsy. NaV1.1(+/-) Dravet Syndrome mice in C57BL/6 genetic background exhibit severe seizures, cognitive and social impairments, and premature death. Here we show that Dravet Syndrome mice in pure 129/SvJ genetic background have many fewer seizures and much less premature death than in pure C57BL/6 background. These mice also have a higher threshold for thermally induced seizures, fewer myoclonic seizures, and no cognitive impairment, similar to patients with Genetic Epilepsy with Febrile Seizures Plus. Consistent with this mild phenotype, mutation of NaV1.1 channels has much less physiological effect on neuronal excitability in 129/SvJ mice. In hippocampal slices, the excitability of CA1 Stratum Oriens interneurons is selectively impaired, while the excitability of CA1 pyramidal cells is unaffected. NaV1.1 haploinsufficiency results in increased rheobase and threshold for action potential firing and impaired ability to sustain high-frequency firing. Moreover, deletion of NaV1.1 markedly reduces the amplification and integration of synaptic events, further contributing to reduced excitability of interneurons. Excitability is less impaired in inhibitory neurons of Dravet Syndrome mice in 129/SvJ genetic background. Because specific deletion of NaV1.1 in forebrain GABAergic interneuons is sufficient to cause the symptoms of Dravet Syndrome in mice, our results support the conclusion that the milder phenotype in 129/SvJ mice is caused by lesser impairment of sodium channel function and electrical excitability in their forebrain interneurons. This mild impairment of excitability of interneurons leads to a milder disease phenotype in 129/SvJ mice, similar to Genetic Epilepsy with Febrile Seizures Plus in humans.
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Affiliation(s)
- Moran Rubinstein
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Ruth E Westenbroek
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Frank H Yu
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Christina J Jones
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - Todd Scheuer
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA
| | - William A Catterall
- Department of Pharmacology, University of Washington, Seattle, WA 98195-7280, USA.
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10
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Scheffer IE, Dravet C. Transition to adult life in the monogenic epilepsies. Epilepsia 2014; 55 Suppl 3:12-5. [DOI: 10.1111/epi.12707] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/30/2014] [Indexed: 11/29/2022]
Affiliation(s)
- Ingrid E. Scheffer
- The Florey Institute; Austin Health and Royal Children's Hospital; University of Melbourne; Melbourne Victoria Australia
| | - Charlotte Dravet
- Centre Saint-Paul-Hospital Henri Gastaut; Marseille France
- Catholic University; Rome Italy
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11
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Ferraro TN, Dlugos DJ, Buono RJ. Role of genetics in the diagnosis and treatment of epilepsy. Expert Rev Neurother 2014; 6:1789-800. [PMID: 17181426 DOI: 10.1586/14737175.6.12.1789] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Epilepsy is a heterogeneous group of multifactorial diseases, the vast majority determined by interactions between many genes and environmental factors; however, there are rare epilepsy syndromes that can be caused by a single gene mutation and are inherited according to classical mendelian genetic principles. Finding disease-causing genetic mutations in epilepsy has provided new opportunities for aiding diagnosis and developing therapies. Thus, the discovery of KCNQ2 mutations in benign familial neonatal convulsions, SCN1A mutations in severe myoclonic epilepsy of infancy and in generalized epilepsy with febrile seizures plus, and CHRA4 and CHRB2 mutations in autosomal-dominant nocturnal frontal lobe epilepsy, has led to the establishment of epilepsy as a disorder of ion channel function and, furthermore, has led to the introduction of genetic tests that are available clinically to aid in diagnosis and treatment. At the present time, clinical use of genetic testing in epilepsy is greatest in suspected cases of severe myoclonic epilepsy of infancy, generalized epilepsy with febrile seizures plus, atypical cases of benign familial neonatal convulsions and 'occult' cases of autosomal-dominant nocturnal frontal lobe epilepsy without a family history. Overall, clinical use is limited by the low number of documented disease-associated mutations and the uncertain clinical significance of many test results. Further elucidation of the relationship between gene mutations and channel function will add value to genetic testing in the future, as will better characterization of the association between gene mutations and clinical phenotypes.
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Affiliation(s)
- Thomas N Ferraro
- University of Pennsylvania, Department of Psychiatry, 125 S.31 Street, Room 2209 TRL, Philadelphia, PA 19104-3403, USA.
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13
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Guzzetta F. Cognitive and behavioral characteristics of children with Dravet syndrome: An overview. Epilepsia 2011; 52 Suppl 2:35-8. [DOI: 10.1111/j.1528-1167.2011.02999.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Abstract
Severe myoclonic epilepsy of infancy (SMEI) is a complex form of epilepsy that was first described in France in 1978. Because the myoclonic component of this epilepsy is not always present and because some variability has been observed in the symptomatology, the name was changed to Dravet syndrome in 1989. The genetic aetiology of this epilepsy was discovered in 2001, and since then numerous studies have contributed to a better knowledge of the disease. Around 70% of affected patients are carriers of a mutation on the alpha subunit of the SCN1A gene. An accurate analysis of the clinical features leads to the distinction between typical and atypical forms, both with the same unfavourable prognosis and the same genetic background. However, many studies are being conducted in order to establish correlations between phenotypes and genotypes, and to understand the factors underlying the cognitive impairment of the affected patients.
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Verbeek NE, van Kempen M, Gunning WB, Renier WO, Westland B, Lindhout D, Brilstra EH. Adults with a history of possible Dravet syndrome: an illustration of the importance of analysis of the SCN1A gene. Epilepsia 2011; 52:e23-5. [PMID: 21371021 DOI: 10.1111/j.1528-1167.2011.02982.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Most patients with Dravet syndrome have de novo mutations in the neuronal voltage-gated sodium channel type 1 (SCN1A) gene. We report on two unrelated fathers with severe childhood epilepsy compatible with a possible diagnosis of Dravet syndrome, who both have a child with Dravet syndrome. Analysis of the SCN1A gene revealed a pathogenic mutation in both children. One father exhibited somatic mosaicism for the mutation detected in his son. A relatively favorable cognitive outcome in patients with Dravet syndrome patients may be explained by somatic mosaicism for the SCN1A mutation in brain tissue. A mild form of Dravet syndrome in adult patients is associated with a high recurrence risk and possibly a more severe epilepsy phenotype in their offspring.
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Affiliation(s)
- Nienke E Verbeek
- DBG-Department of Medical Genetics, University Medical Centre Utrecht, Utrecht, The Netherlands.
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Chieffo D, Ricci D, Baranello G, Martinelli D, Veredice C, Lettori D, Battaglia D, Dravet C, Mercuri E, Guzzetta F. Early development in Dravet syndrome; visual function impairment precedes cognitive decline. Epilepsy Res 2011; 93:73-9. [DOI: 10.1016/j.eplepsyres.2010.10.015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2010] [Revised: 10/26/2010] [Accepted: 10/31/2010] [Indexed: 11/25/2022]
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18
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The uncommon causes of status epilepticus: a systematic review. Epilepsy Res 2010; 91:111-22. [PMID: 20709500 DOI: 10.1016/j.eplepsyres.2010.07.015] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2010] [Revised: 07/14/2010] [Accepted: 07/18/2010] [Indexed: 01/01/2023]
Abstract
This paper reports the first systematic review of uncommon causes of status epilepticus reported in the literature between 1990 and 2008. Uncommon causes are defined as those not listed in the main epidemiological studies of status epilepticus. 181 causes were identified. These were easily categorised into 5 specific aetiological categories: immunological disorders, mitochondrial disorders, infectious diseases, genetic disorders and drugs/toxins. A sixth category of 'other causes' has also been included. Knowledge of these causes is important for clinical management and treatment, and also for a better understanding of the pathophysiology of status epilepticus.
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Akiyama M, Kobayashi K, Yoshinaga H, Ohtsuka Y. A long-term follow-up study of Dravet syndrome up to adulthood. Epilepsia 2009; 51:1043-52. [DOI: 10.1111/j.1528-1167.2009.02466.x] [Citation(s) in RCA: 156] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Orrico A, Galli L, Grosso S, Buoni S, Pianigiani R, Balestri P, Sorrentino V. Mutational analysis of the SCN1A, SCN1B and GABRG2 genes in 150 Italian patients with idiopathic childhood epilepsies. Clin Genet 2009; 75:579-81. [PMID: 19522081 DOI: 10.1111/j.1399-0004.2009.01155.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Over the past 10 years mutations in voltage-gated sodium channels (Na(v)s) have become closely associated with inheritable forms of epilepsy. One isoform in particular, Na(v)1.1 (gene symbol SCN1A), appears to be a superculprit, registering with more than 330 mutations to date. The associated phenotypes range from benign febrile seizures to extremely serious conditions, such as Dravet's syndrome (SMEI). Despite the wealth of information, mutational analyses are cumbersome, owing to inconsistencies among the Na(v)1.1 sequences to which different research groups refer. Splicing variability is the core problem: Na(v)1.1 co-exists in three isoforms, two of them lack 11 or 28 amino acids compared to full-length Na(v).1.1. This review establishes a standardized nomenclature for Na(v)1.1 variants so as to provide a platform from which future mutation analyses can be started without need for up-front data normalization. An online resource--SCN1A infobase--is introduced.
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Affiliation(s)
- Christoph Lossin
- Department of Neurology, University of California, Davis, 4635 2nd Avenue, Room 1004A, Sacramento, CA 95817, USA.
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