1
|
Echevarria-Cooper DM, Kearney JA. Evaluating the interplay between estrous cyclicity and flurothyl-induced seizure susceptibility in Scn2a K1422E mice. MICROPUBLICATION BIOLOGY 2023; 2023:10.17912/micropub.biology.000850. [PMID: 38162411 PMCID: PMC10757737 DOI: 10.17912/micropub.biology.000850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 10/30/2023] [Accepted: 12/12/2023] [Indexed: 01/03/2024]
Abstract
Recently, we demonstrated that Scn2a K1422E female mice showed a distinct distribution of flurothyl-induced seizure thresholds. To evaluate whether the estrous cycle contributes to this effect, estrous cycle monitoring was performed in mice that had undergone ovariectomy, sham surgery, or no treatment prior to seizure induction. Ovariectomy did not affect the non-unimodal distribution of flurothyl seizure thresholds observed in Scn2a K1422E females. Additionally, seizure thresholds were not associated with estrous cycle stage in mice that underwent sham surgery or in non-surgerized (intact) mice. Interestingly, intact Scn2a K1422E females showed evidence of disrupted estrous cyclicity, an effect not previously described in a genetic epilepsy model.
Collapse
|
2
|
Borowicz-Reutt K, Czernia J, Krawczyk M. Genetic Background of Epilepsy and Antiepileptic Treatments. Int J Mol Sci 2023; 24:16280. [PMID: 38003469 PMCID: PMC10671416 DOI: 10.3390/ijms242216280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/01/2023] [Accepted: 11/08/2023] [Indexed: 11/26/2023] Open
Abstract
Advanced identification of the gene mutations causing epilepsy syndromes is expected to translate into faster diagnosis and more effective treatment of these conditions. Over the last 5 years, approximately 40 clinical trials on the treatment of genetic epilepsies have been conducted. As a result, some medications that are not regular antiseizure drugs (e.g., soticlestat, fenfluramine, or ganaxolone) have been introduced to the treatment of drug-resistant seizures in Dravet, Lennox-Gastaut, maternally inherited chromosome 15q11.2-q13.1 duplication (Dup 15q) syndromes, and protocadherin 19 (PCDH 19)-clusterig epilepsy. And although the effects of soticlestat, fenfluramine, and ganaxolone are described as promising, they do not significantly affect the course of the mentioned epilepsy syndromes. Importantly, each of these syndromes is related to mutations in several genes. On the other hand, several mutations can occur within one gene, and different gene variants may be manifested in different disease phenotypes. This complex pattern of inheritance contributes to rather poor genotype-phenotype correlations. Hence, the detection of a specific mutation is not synonymous with a precise diagnosis of a specific syndrome. Bearing in mind that seizures develop as a consequence of the predominance of excitatory over inhibitory processes, it seems reasonable that mutations in genes encoding sodium and potassium channels, as well as glutamatergic and gamma-aminobutyric (GABA) receptors, play a role in the pathogenesis of epilepsy. In some cases, different pathogenic variants of the same gene can result in opposite functional effects, determining the effectiveness of therapy with certain medications. For instance, seizures related to gain-of-function (GoF) mutations in genes encoding sodium channels can be successfully treated with sodium channel blockers. On the contrary, the same drugs may aggravate seizures related to loss-of-function (LoF) variants of the same genes. Hence, knowledge of gene mutation-treatment response relationships facilitates more favorable selection of drugs for anticonvulsant therapy.
Collapse
Affiliation(s)
- Kinga Borowicz-Reutt
- Independent Unit of Experimental Neuropathophysiology, Department of Toxicology, Medical University of Lublin, Jaczewskiego 8b, 20-090 Lublin, Poland; (J.C.); (M.K.)
| | | | | |
Collapse
|
3
|
Lenge M, Balestrini S, Mei D, Macconi L, Caligiuri ME, Cuccarini V, Aquino D, Mazzi F, d’Incerti L, Darra F, Bernardina BD, Guerrini R. Morphometry and network-based atrophy patterns in SCN1A-related Dravet syndrome. Cereb Cortex 2023; 33:9532-9541. [PMID: 37344172 PMCID: PMC10431750 DOI: 10.1093/cercor/bhad224] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Revised: 06/04/2023] [Accepted: 06/05/2023] [Indexed: 06/23/2023] Open
Abstract
Mutations of the voltage-gated sodium channel SCN1A gene (MIM#182389) are among the most clinically relevant epilepsy-related genetic mutations and present variable phenotypes, from the milder genetic epilepsy with febrile seizures plus to Dravet syndrome, a severe developmental and epileptic encephalopathy. Qualitative neuroimaging studies have identified malformations of cortical development in some patients and mild atrophic changes, partially confirmed by quantitative studies. Precise correlations between MRI findings and clinical variables have not been addressed. We used morphometric methods and network-based models to detect abnormal brain structural patterns in 34 patients with SCN1A-related epilepsy, including 22 with Dravet syndrome. By measuring the morphometric characteristics of the cortical mantle and volume of subcortical structures, we found bilateral atrophic changes in the hippocampus, amygdala, and the temporo-limbic cortex (P-value < 0.05). By correlating atrophic patterns with brain connectivity profiles, we found the region of the hippocampal formation as the epicenter of the structural changes. We also observed that Dravet syndrome was associated with more severe atrophy patterns with respect to the genetic epilepsy with febrile seizures plus phenotype (r = -0.0613, P-value = 0.03), thus suggesting that both the underlying mutation and seizure severity contribute to determine atrophic changes.
Collapse
Affiliation(s)
- Matteo Lenge
- Neuroscience Department, Meyer Children’s Hospital IRCCS, 50139, Florence, Italy
| | - Simona Balestrini
- Neuroscience Department, Meyer Children’s Hospital IRCCS, 50139, Florence, Italy
| | - Davide Mei
- Neuroscience Department, Meyer Children’s Hospital IRCCS, 50139, Florence, Italy
| | - Letizia Macconi
- Neuroradiology Unit, Meyer Children’s Hospital IRCCS, 50139, Florence, Italy
| | - Maria Eugenia Caligiuri
- Neuroscience Research Center, Department of Medical and Surgical Sciences, Magna Grecia University, 88100, Catanzaro, Italy
| | - Valeria Cuccarini
- Neuroradiology Unit, Fondazione IRCCS Neurologico Carlo Besta, 20100, Milan, Italy
| | - Domenico Aquino
- Neuroradiology Unit, Fondazione IRCCS Neurologico Carlo Besta, 20100, Milan, Italy
| | - Federica Mazzi
- Neuroradiology Unit, Fondazione IRCCS Neurologico Carlo Besta, 20100, Milan, Italy
| | - Ludovico d’Incerti
- Neuroradiology Unit, Meyer Children’s Hospital IRCCS, 50139, Florence, Italy
| | - Francesca Darra
- Child Neuropsychiatry Unit, Department of Engineering for Innovation Medicine University of Verona, 37100, Verona, Italy
| | - Bernardo Dalla Bernardina
- Child Neuropsychiatry Unit, Department of Engineering for Innovation Medicine University of Verona, 37100, Verona, Italy
- Pediatric Epilepsy Research Center (CREP), Azienda Ospedaliera Universitaria Integrata, 37100, Verona, Italy
| | - Renzo Guerrini
- Neuroscience Department, Meyer Children’s Hospital IRCCS, 50139, Florence, Italy
| |
Collapse
|
4
|
Echevarria-Cooper DM, Hawkins NA, Kearney JA. Strain-dependent effects on neurobehavioral and seizure phenotypes in Scn2aK1422E mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.06.543929. [PMID: 37333275 PMCID: PMC10274703 DOI: 10.1101/2023.06.06.543929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/20/2023]
Abstract
Pathogenic variants in SCN2A are associated with a range of neurodevelopmental disorders (NDD). Despite being largely monogenic, SCN2A-related NDD show considerable phenotypic variation and complex genotype-phenotype correlations. Genetic modifiers can contribute to variability in disease phenotypes associated with rare driver mutations. Accordingly, different genetic backgrounds across inbred rodent strains have been shown to influence disease-related phenotypes, including those associated with SCN2A-related NDD. Recently, we developed a mouse model of the variant SCN2A-p.K1422E that was maintained as an isogenic line on the C57BL/6J (B6) strain. Our initial characterization of NDD phenotypes in heterozygous Scn2aK1422E mice revealed alterations in anxiety-related behavior and seizure susceptibility. To determine if background strain affects phenotype severity in the Scn2aK1422E mouse model, phenotypes of mice on B6 and [DBA/2J×B6]F1 hybrid (F1D2) strains were compared. Convergent evidence from neurobehavioral assays demonstrated lower anxiety-like behavior in Scn2aK1422E mice compared to wild-type and further suggested that this effect is more pronounced on the B6 background compared to the F1D2 background. Although there were no strain-dependent differences in occurrence of rare spontaneous seizures, response to the chemoconvulsant kainic acid revealed differences in seizure generalization and lethality risk, with variation based on strain and sex. Continued examination of strain-dependent effects in the Scn2aK1422E mouse model could reveal genetic backgrounds with unique susceptibility profiles that would be relevant for future studies on specific traits and enable the identification of highly penetrant phenotypes and modifier genes that could provide clues about the primary pathogenic mechanism of the K1422E variant.
Collapse
Affiliation(s)
- Dennis M. Echevarria-Cooper
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| | - Nicole A. Hawkins
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Jennifer A. Kearney
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| |
Collapse
|
5
|
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: 0] [Impact Index Per Article: 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.
Collapse
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
| |
Collapse
|
6
|
Echevarria-Cooper DM, Kearney JA. Evaluating the interplay between estrous cyclicity and induced seizure susceptibility in Scn2aK1422E mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.27.538584. [PMID: 37163100 PMCID: PMC10168397 DOI: 10.1101/2023.04.27.538584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Pathogenic variants in SCN2A are associated with a range of neurodevelopmental disorders (NDD). SCN2A-related NDD show wide phenotypic heterogeneity, suggesting that modifying factors must be considered in order to properly elucidate the mechanisms of pathogenic variants. Recently, we characterized neurological phenotypes in a mouse model of the variant SCN2A-p.K1422E. We demonstrated that heterozygous Scn2aK1422E female mice showed a distinct, reproducible distribution of flurothyl-induced seizure thresholds. Women with epilepsy often show a cyclical pattern of altered seizure susceptibility during specific phases of the menstrual cycle which can be attributed to fluctuations in hormones and corresponding changes in neurosteroid levels. Rodent models have been used extensively to examine the relationship between the estrous (menstrual) cycle, steroid hormones, and seizure susceptibility. However, the effects of the estrous cycle on seizure susceptibility have not been evaluated in the context of an epilepsy-associated genetic variant. To determine whether the estrous cycle affects susceptibility to flurothyl-induced seizures in Scn2aK1422E female mice, estrous cycle monitoring was performed in mice that had undergone ovariectomy (OVX), sham surgery, or no treatment prior to seizure induction. Removing the influence of circulating sex hormones via OVX did not affect the non-unimodal distribution of flurothyl seizure thresholds observed in Scn2aK1422E females. Additionally, flurothyl seizure thresholds were not associated with estrous cycle stage in mice that underwent sham surgery or were untreated. These data suggest that variation in Scn2aK1422E flurothyl seizure threshold is not significantly influenced by the estrous cycle and, by extension, fluctuations in ovarian hormones. Interestingly, untreated Scn2aK1422E females showed evidence of disrupted estrous cyclicity, an effect not previously described in a genetic epilepsy model. This unexpected result highlights the importance of considering sex specific effects and the estrous cycle in support of more inclusive biomedical research.
Collapse
Affiliation(s)
- Dennis M. Echevarria-Cooper
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| | - Jennifer A. Kearney
- Department of Pharmacology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL 60611, USA
| |
Collapse
|
7
|
Kim EH, Shin J, Lee BK. Neonatal seizures: diagnostic updates based on new definition and classification. Clin Exp Pediatr 2022; 65:387-397. [PMID: 35381171 PMCID: PMC9348949 DOI: 10.3345/cep.2021.01361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/05/2021] [Indexed: 11/27/2022] Open
Abstract
Neonatal seizures are the most common neurological symptoms caused by various etiologies in the neonatal period, but their diagnosis and treatment are challenging because their pathophysiology and electroclinical manifestations differ from those of patients in older age groups. Many seizures present as electrographic-only events without clinical signs or as obscure clinical manifestations that are difficult to distinguish from other neonatal behaviors. Accordingly, a new definition and classification of neonatal seizures was recently proposed by the International League Against Epilepsy Task Force on neonatal seizures, highlighting the role of electroencephalography in diagnosing and treating neonatal seizures. Neonatal seizures are defined as electrographic events with sudden, paroxysmal, and abnormal alteration of activity and divided into electroclinical seizures and electrographic-only seizures according to their clinical signs, thus excluding clinical events without an electrographic correlation. Seizure types are described by their predominant clinical features and divided into motor (automatisms, clonic, epileptic spasms, myoclonic, tonic, and sequential), nonmotor (autonomic and behavioral arrest), and unclassified. Although many neonatal seizures are acute reactive events caused by hypoxic-ischemic encephalopathy or vascular insults, structural, genetic, or metabolic etiologies of neonatal-onset epilepsy should also be thoroughly evaluated to determine their appropriate management.
Collapse
Affiliation(s)
- Eun-Hee Kim
- Department of Pediatrics, Chungnam National University Sejong Hospital, Chungnam National University School of Medicine, Sejong, Korea
| | - Jeongmin Shin
- Department of Pediatrics, Chungnam National University Sejong Hospital, Chungnam National University School of Medicine, Sejong, Korea
| | - Byoung Kook Lee
- Department of Pediatrics, Chungnam National University Sejong Hospital, Chungnam National University School of Medicine, Sejong, Korea
| |
Collapse
|
8
|
Sharkov A, Sparber P, Stepanova A, Pyankov D, Korostelev S, Skoblov M. Case Report: Phenotype-Driven Diagnosis of Atypical Dravet-Like Syndrome Caused by a Novel Splicing Variant in the SCN2A Gene. Front Genet 2022; 13:888481. [PMID: 35711923 PMCID: PMC9194094 DOI: 10.3389/fgene.2022.888481] [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: 03/02/2022] [Accepted: 04/19/2022] [Indexed: 01/18/2023] Open
Abstract
Febrile-associated epileptic encephalopathy is a large genetically heterogeneous group that is associated with pathogenic variants in SCN1A, PCDH19, SCN2A, SCN8A, and other genes. The disease onset ranges from neonatal or early-onset epileptic encephalopathy to late-onset epilepsy after 18 months. Some etiology-specific epileptic encephalopathies have target therapy which can serve as a clue for the correct genetic diagnosis. We present genetic, clinical, electroencephalographic, and behavioral features of a 4-year-old girl with epileptic encephalopathy related to a de novo intronic variant in the SCN2A gene. Initial NGS analysis revealed a frameshift variant in the KDM6A gene and a previously reported missense variant in SCN1A. Due to lack of typical clinical signs of Kabuki syndrome, we performed X-chromosome inactivation that revealed nearly complete skewed inactivation. Segregation analysis showed that the SCN1A variant was inherited from a healthy father. The proband had resistance to multiple antiseizure medications but responded well to sodium channel inhibitor Carbamazepine. Reanalysis of NGS data by a neurogeneticist revealed a previously uncharacterized heterozygous variant c.1035-7A>G in the SCN2A gene. Minigene assay showed that the c.1035-7A>G variant activates a cryptic intronic acceptor site which leads to 6-nucleotide extension of exon 9 (NP_066287.2:p.(Gly345_Gln346insTyrSer). SCN2A encephalopathy is a recognizable severe phenotype. Its electro-clinical and treatment response features can serve as a hallmark. In such a patient, reanalysis of genetic data is strongly recommended in case of negative or conflicting results of DNA analysis.
Collapse
Affiliation(s)
- Artem Sharkov
- Genomed Ltd., Moscow, Russia.,Veltischev Research and Clinical Institute for Pediatrics of the Pirogov Russian National Research Medical University, Moscow, Russia
| | - Peter Sparber
- Research Centre for Medical Genetics, Moscow, Russia
| | | | | | | | | |
Collapse
|
9
|
Functional correlates of clinical phenotype and severity in recurrent SCN2A variants. Commun Biol 2022; 5:515. [PMID: 35637276 PMCID: PMC9151917 DOI: 10.1038/s42003-022-03454-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 05/05/2022] [Indexed: 01/24/2023] Open
Abstract
In SCN2A-related disorders, there is an urgent demand to establish efficient methods for determining the gain- (GoF) or loss-of-function (LoF) character of variants, to identify suitable candidates for precision therapies. Here we classify clinical phenotypes of 179 individuals with 38 recurrent SCN2A variants as early-infantile or later-onset epilepsy, or intellectual disability/autism spectrum disorder (ID/ASD) and assess the functional impact of 13 variants using dynamic action potential clamp (DAPC) and voltage clamp. Results show that 36/38 variants are associated with only one phenotypic group (30 early-infantile, 5 later-onset, 1 ID/ASD). Unexpectedly, we revealed major differences in outcome severity between individuals with the same variant for 40% of early-infantile variants studied. DAPC was superior to voltage clamp in predicting the impact of mutations on neuronal excitability and confirmed GoF produces early-infantile phenotypes and LoF later-onset phenotypes. For one early-infantile variant, the co-expression of the α1 and β2 subunits of the Nav1.2 channel was needed to unveil functional impact, confirming the prediction of 3D molecular modeling. Neither DAPC nor voltage clamp reliably predicted phenotypic severity of early-infantile variants. Genotype, phenotypic group and DAPC are accurate predictors of the biophysical impact of SCN2A variants, but other approaches are needed to predict severity. A comprehensive biophysical analysis of disease-associated mutations in the voltage-gated sodium channel gene, SCN2A, suggests that dynamic action potential clamp may be a better predictor than voltage clamp of how these mutations alter neuronal excitability, though other approaches are needed to predict severity.
Collapse
|
10
|
Echevarria-Cooper DM, Hawkins NA, Misra SN, Huffman AM, Thaxton T, Thompson CH, Ben-Shalom R, Nelson AD, Lipkin AM, George AL, Bender KJ, Kearney JA. Cellular and behavioral effects of altered NaV1.2 sodium channel ion permeability in Scn2aK1422E mice. Hum Mol Genet 2022; 31:2964-2988. [PMID: 35417922 PMCID: PMC9433730 DOI: 10.1093/hmg/ddac087] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/28/2022] [Accepted: 04/09/2022] [Indexed: 11/13/2022] Open
Abstract
Genetic variants in SCN2A, encoding the NaV1.2 voltage-gated sodium channel, are associated with a range of neurodevelopmental disorders with overlapping phenotypes. Some variants fit into a framework wherein gain-of-function missense variants that increase neuronal excitability lead to developmental and epileptic encephalopathy, while loss-of-function variants that reduce neuronal excitability lead to intellectual disability and/or autism spectrum disorder (ASD) with or without co-morbid seizures. One unique case less easily classified using this framework is the de novo missense variant SCN2A-p.K1422E, associated with infant-onset developmental delay, infantile spasms and features of ASD. Prior structure–function studies demonstrated that K1422E substitution alters ion selectivity of NaV1.2, conferring Ca2+ permeability, lowering overall conductance and conferring resistance to tetrodotoxin (TTX). Based on heterologous expression of K1422E, we developed a compartmental neuron model incorporating variant channels that predicted reductions in peak action potential (AP) speed. We generated Scn2aK1422E mice and characterized effects on neurons and neurological/neurobehavioral phenotypes. Cultured cortical neurons from heterozygous Scn2aK1422E/+ mice exhibited lower current density with a TTX-resistant component and reversal potential consistent with mixed ion permeation. Recordings from Scn2aK1442E/+ cortical slices demonstrated impaired AP initiation and larger Ca2+ transients at the axon initial segment during the rising phase of the AP, suggesting complex effects on channel function. Scn2aK1422E/+ mice exhibited rare spontaneous seizures, interictal electroencephalogram abnormalities, altered induced seizure thresholds, reduced anxiety-like behavior and alterations in olfactory-guided social behavior. Overall, Scn2aK1422E/+ mice present with phenotypes similar yet distinct from other Scn2a models, consistent with complex effects of K1422E on NaV1.2 channel function.
Collapse
Affiliation(s)
- Dennis M Echevarria-Cooper
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL, USA, 60611
| | - Nicole A Hawkins
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611
| | - Sunita N Misra
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611.,Departments of Pediatrics, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611.,Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA 60611
| | - Alexandra M Huffman
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611
| | - Tyler Thaxton
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611
| | - Christopher H Thompson
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611
| | - Roy Ben-Shalom
- Mind Institute and Department of Neurology, University of California, Davis, Sacramento, CA, United States 95817
| | - Andrew D Nelson
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, CA, USA 94158
| | - Anna M Lipkin
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, CA, USA 94158.,Neuroscience Graduate Program, University of California, San Francisco, CA, USA 94158
| | - Alfred L George
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL, USA, 60611
| | - Kevin J Bender
- Department of Neurology, Kavli Institute for Fundamental Neuroscience, Weill Institute for Neurosciences, University of California, San Francisco, CA, USA 94158
| | - Jennifer A Kearney
- Departments of Pharmacology, Northwestern University Feinberg School of Medicine; Chicago, IL, USA 60611.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL, USA, 60611
| |
Collapse
|
11
|
Zeng Q, Yang Y, Duan J, Niu X, Chen Y, Wang D, Zhang J, Chen J, Yang X, Li J, Yang Z, Jiang Y, Liao J, Zhang Y. SCN2A-Related Epilepsy: The Phenotypic Spectrum, Treatment and Prognosis. Front Mol Neurosci 2022; 15:809951. [PMID: 35431799 PMCID: PMC9005871 DOI: 10.3389/fnmol.2022.809951] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 02/14/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE The aim of this study was to analyze the phenotypic spectrum, treatment, and prognosis of 72 Chinese children with SCN2A variants. METHODS The SCN2A variants were detected by next-generation sequencing. All patients were followed up at a pediatric neurology clinic in our hospital or by telephone. RESULTS In 72 patients with SCN2A variants, the seizure onset age ranged from the first day of life to 2 years and 6 months. The epilepsy phenotypes included febrile seizures (plus) (n = 2), benign (familial) infantile epilepsy (n = 9), benign familial neonatal-infantile epilepsy (n = 3), benign neonatal epilepsy (n = 1), West syndrome (n = 16), Ohtahara syndrome (n = 15), epilepsy of infancy with migrating focal seizures (n = 2), Dravet syndrome (n = 1), early infantile epileptic encephalopathy (n = 15), and unclassifiable developmental and epileptic encephalopathy (n = 8). Approximately 79.2% (57/72) patients had varying degrees of developmental delay. All patients had abnormal MRI findings with developmental delay. 91.7% (55/60) patients with de novo SCN2A variants had development delay, while only 16.7% (2/12) patients with inherited SCN2A variants had abnormal development. 83.9% (26/31) SCN2A variants that were located in transmembrane regions of the protein were detected in patients with development delay. Approximately 69.2% (9/13) SCN2A variants detected in patients with normal development were located in the non-transmembrane regions. Approximately 54.2% (39/72) patients were seizure-free at a median age of 8 months. Oxcarbazepine has been used by 38 patients, and seizure-free was observed in 11 of them (11/38, 28.9%), while 6 patients had seizure worsening by oxcarbazepine. All 3 patients used oxcarbazepine and with seizure onset age > 1 year presented seizure exacerbation after taking oxcarbazepine. Valproate has been used by 53 patients, seizure-free was observed in 22.6% (12/53) of them. CONCLUSION The phenotypic spectrum of SCN2A-related epilepsy was broad, ranging from benign epilepsy in neonate and infancy to severe epileptic encephalopathy. Oxcarbazepine and valproate were the most effective drugs in epilepsy patients with SCN2A variants. Sodium channel blockers often worsen seizures in patients with seizure onset beyond 1 year of age. Abnormal brain MRI findings and de novo variations were often related to poor prognosis. Most SCN2A variants located in transmembrane regions were related to patients with developmental delay.
Collapse
Affiliation(s)
- Qi Zeng
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Ying Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jing Duan
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
| | - Xueyang Niu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yi Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Dan Wang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jing Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jiaoyang Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaoling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jinliang Li
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuwu Jiang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jianxiang Liao
- Department of Neurology, Shenzhen Children’s Hospital, Shenzhen, China
- *Correspondence: Jianxiang Liao,
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
- Yuehua Zhang,
| |
Collapse
|
12
|
Craiu D, Rener Primec Z, Lagae L, Vigevano F, Trinka E, Specchio N, Bakhtadze S, Cazacu C, Golli T, Zuberi SM. Vaccination and childhood epilepsies. Eur J Paediatr Neurol 2022; 36:57-68. [PMID: 34922162 DOI: 10.1016/j.ejpn.2021.11.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 11/08/2021] [Accepted: 11/24/2021] [Indexed: 10/19/2022]
Abstract
INTRODUCTION The evidence relating vaccination to febrile seizures and epilepsy is evaluated with an emphasis on febrile seizures (FS), Dravet syndrome (DS), West syndrome, and other developmental and epileptic encephalopathies. METHODS A systematic literature review using search words vaccination/immunization AND febrile seizures/epilepsy/Dravet/epileptic encephalopathy/developmental encephalopathy was performed. The role of vaccination as the cause/trigger/aggravation factor for FS or epilepsies and preventive measures were analyzed. RESULTS From 1428 results, 846 duplicates and 447 irrelevant articles were eliminated; 120 were analyzed. CONCLUSIONS There is no evidence that vaccinations cause epilepsy in healthy populations. Vaccinations do not cause epileptic encephalopathies but may be non-specific triggers to seizures in underlying structural or genetic etiologies. The first seizure in DS may be earlier in vaccinated versus non-vaccinated patients, but developmental outcome is similar in both groups. Children with a personal or family history of FS or epilepsy should receive all routine vaccinations. This recommendation includes DS. The known risks of the infectious diseases prevented by immunization are well established. Vaccination should be deferred in case of acute illness. Acellular pertussis DTaP (diphtheria-tetanus-pertussis) is recommended. The combination of certain vaccine types may increase the risk of febrile seizures however the public health benefit of separating immunizations has not been proven. Measles-containing vaccine should be administered at age 12-15 months. Routine prophylactic antipyretics are not indicated, as there is no evidence of decreased FS risk and they can attenuate the antibody response following vaccination. Prophylactic measures (preventive antipyretic medication) are recommended in DS due to the increased risk of prolonged seizures with fever.
Collapse
Affiliation(s)
- Dana Craiu
- Carol Davila University of Medicine and Pharmacy, Faculty of Medicine, Department of Neurosciences, Pediatric Neurology Discipline II, Strada Dionisie Lupu No. 37, postal code: 020021, Bucharest/S2, Romania; Pediatric Neurology Clinic, Center of Expertise for Rare Disorders in Pediatric Neurology, EpiCARE member, Sos. Berceni 10, Bucharest/S4, Romania.
| | - Zvonka Rener Primec
- Department of Child, Adolescent and Developmental Neurology, Children's Hospital, University Medical Center Ljubljana Bohoričeva 20, 1000, Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia.
| | - Lieven Lagae
- University of Leuven, Department of Development and Regeneration, Section Paediatric Neurology, Herestraat 49, 3000, Leuven, Belgium.
| | - Federico Vigevano
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Piazza S. Onofrio, 4, 00151, Rome, Italy.
| | - Eugen Trinka
- Department of Neurology, Christian-Doppler Medical Centre, Paracelsus Medical University, Affiliated Member of the European Reference Network, EpiCARE, 5020, Salzburg, Austria; Neuroscience Institute, Christian-Doppler Medical Centre, Paracelsus Medical University Salzburg, Austria.
| | - Nicola Specchio
- Department of Neuroscience, Bambino Gesù Children's Hospital, IRCCS, Full Member of European Reference Network EpiCARE, Piazza S. Onofrio, 4, 00151, Rome, Italy.
| | - Sophia Bakhtadze
- Department of Paediatric Neurology, Tbilisi State Medical University, 0160, Tbilisi, Georgia.
| | - Cristina Cazacu
- Pediatric Neurology Clinic, Center of Expertise for Rare Disorders in Pediatric Neurology, EpiCARE member, Sos. Berceni 10, Bucharest/S4, Romania.
| | - Tanja Golli
- Department of Child, Adolescent and Developmental Neurology, Children's Hospital, University Medical Center Ljubljana Bohoričeva 20, 1000, Ljubljana, Slovenia; Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000, Ljubljana, Slovenia.
| | - Sameer M Zuberi
- Paediatric Neurosciences, Royal Hospital for Children, Glasgow, UK; Institute of Health & Wellbeing, University of Glasgow, Glasgow, UK.
| |
Collapse
|
13
|
de la Jara J, Vásquez-Hernández C, Ramírez-Rojo E, Moya-Vilches J. Uncommon epileptic syndromes in children: a review. Seizure 2021; 90:17-27. [DOI: 10.1016/j.seizure.2021.05.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 05/02/2021] [Accepted: 05/04/2021] [Indexed: 10/21/2022] Open
|
14
|
Abstract
Pathogenic variants in epilepsy genes result in a spectrum of clinical severity. One source of phenotypic heterogeneity is modifier genes that affect expressivity of a primary pathogenic variant. Mouse epilepsy models also display varying degrees of clinical severity on different genetic backgrounds. Mice with heterozygous deletion of Scn1a (Scn1a+/−) model Dravet syndrome, a severe epilepsy most often caused by SCN1A haploinsufficiency. Scn1a+/− mice recapitulate features of Dravet syndrome, including spontaneous seizures, sudden death, and cognitive/behavioral deficits. Scn1a+/− mice maintained on the 129S6/SvEvTac (129) strain have normal lifespan and no spontaneous seizures. In contrast, admixture with C57BL/6J (B6) results in epilepsy and premature lethality. We previously mapped Dravet Survival Modifier loci (Dsm1-Dsm5) responsible for strain-dependent differences in survival. Gabra2, encoding the GABAA α2 subunit, was nominated as a candidate modifier at Dsm1. Direct measurement of GABAA receptors found lower abundance of α2-containing receptors in hippocampal synapses of B6 mice relative to 129. We also identified a B6-specific single nucleotide deletion within Gabra2 that lowers mRNA and protein by nearly 50%. Repair of this deletion reestablished normal levels of Gabra2 expression. In this study, we used B6 mice with a repaired Gabra2 allele to evaluate Gabra2 as a genetic modifier of severity in Scn1a+/− mice. Gabra2 repair restored transcript and protein expression, increased abundance of α2-containing GABAA receptors in hippocampal synapses, and rescued epilepsy phenotypes of Scn1a+/− mice. These findings validate Gabra2 as a genetic modifier of Dravet syndrome, and support enhancing function of α2-containing GABAA receptors as treatment strategy for Dravet syndrome.
Collapse
|
15
|
Praticò AD, Giallongo A, Arrabito M, D'Amico S, Gauci MC, Lombardo G, Polizzi A, Falsaperla R, Ruggieri M. SCN2A and Its Related Epileptic Phenotypes. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727097] [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
AbstractEpilepsies due to SCN2A mutations can present with a broad range of phenotypes that are still not fully understood. Clinical characteristics of SNC2A-related epilepsy may vary from neonatal benign epilepsy to early-onset epileptic encephalopathy, including Ohtahara syndrome and West syndrome, and epileptic encephalopathies occurring at later ages (usually within the first 10 years of life). Some patient may present with intellectual disability and/or autism or movement disorders and without epilepsy. The heterogeneity of the phenotypes associated to such genetic mutations does not always allow the clinician to address his suspect on this gene. For this reason, diagnosis is usually made after a multiple gene panel examination through next generation sequencing (NGS) or after whole exome sequencing (WES) or whole genome sequencing (WGS). Subsequently, confirmation by Sanger sequencing can be obtained. Mutations in SCN2A are inherited as an autosomal dominant trait. Most individuals diagnosed with SCN2A–benign familial neonatal-infantile seizures (BFNIS) have an affected parent; however, hypothetically, a child may present SCN2A-BNFNIS as the result of a de novo pathogenic variant. Almost all individuals with SCN2A and severe epileptic encephalopathies have a de novo pathogenic variant. SNC2A-related epilepsies have not shown a clear genotype–phenotype correlation; in some cases, a same variant may lead to different presentations even within the same family and this could be due to other genetic factors or to environmental causes. There is no “standardized” treatment for SCN2A-related epilepsy, as it varies in relation to the clinical presentation and the phenotype of the patient, according to its own gene mutation. Treatment is based mainly on antiepileptic drugs, which include classic wide-spectrum drugs, such as valproic acid, levetiracetam, and lamotrigine. However, specific agents, which act directly modulating the sodium channels activity (phenytoin, carbamazepine, oxcarbamazepine, lamotrigine, and zonisamide), have shown positive result, as other sodium channel blockers (lidocaine and mexiletine) or even other drugs with different targets (phenobarbital).
Collapse
Affiliation(s)
- 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
| | - Alessandro Giallongo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Marta Arrabito
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Silvia D'Amico
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Catania, Italy
| | - Maria Cristina Gauci
- 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
| | - Giulia Lombardo
- Pediatrics Postgraduate Residency Program, Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, 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
- 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
| |
Collapse
|
16
|
Melikishvili G, Dulac O, Gataullina S. Neonatal SCN2A encephalopathy: A peculiar recognizable electroclinical sequence. Epilepsy Behav 2020; 111:107187. [PMID: 32603808 DOI: 10.1016/j.yebeh.2020.107187] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 10/24/2022]
Abstract
INTRODUCTION Sodium voltage-gated channel alpha subunit 2 (SCN2A) gene encodes the Nav1.2 subunit of voltage-gated sodium channel in pyramidal neurons. SCN2A gain-of-function mutations are identified more and more often with gene panels and whole exome sequencing. Phenotype ranges from benign neonatal or infantile seizures to severe epileptic encephalopathy. Although large series of patients targeting genetic background point out two main phenotypes with SCN2A encephalopathy, Ohtahara syndrome and malignant migrating partial seizures in infancy (EMPSI), we noticed that in fact, a peculiar clinical and electroencephalogram (EEG) sequence distinct from these syndromes should suggest the diagnosis early. PATIENTS AND METHODS We report three new cases with de novo SCN2A mutations - 166237617C>A p.(Asp1487Glu), c.407T>G p.(Met136Arg), and c.4633A>G p.(Met1545Val) - diagnosed by direct sequencing or genes panel, their follow-up ranging from 4 to 5 years. RESULTS For all three patients, seizures started at two days of life and consisted of apnea and cyanosis with partial clonic or tonic, alternating on both sides with, up to 100/day, evolving to generalized tonic-clonic seizures (GTCS) and epileptic spasms by three months. First EEG showed a discontinuous pattern, evolving to multifocal spikes, by 3 (two patients) and 6 months (one). Seizure frequency decreased progressively by the middle or end of the first year of life. Only less frequent GTCS persisted during the second year of life for two patients. Improvement was observed in two patients with sodium channel blocker (phenytoin) used at age of 1 month for one patient and at 2 years for another one. All patients remained with severe psychomotor delay. DISCUSSION All three infants share a condition different from Ohtahara syndrome in which tonic spasms predominate and suppression-burst pattern is obvious, and from EMPSI, in which partial migrating discharges involve successively the various parts of the brain including occipital regions with oculoclonic seizures, but there is neither discontinuous pattern nor therapeutic response to sodium channel blockers. CONCLUSION Neonatal SCN2A encephalopathy has a recognizable phenotype starting soon after birth with alternating partial motor seizures evolving to infantile spasms and a discontinuous EEG pattern. Seizures improve spontaneously in the first year of life. This electroclinical sequence should indicate the search of SCN2A mutation and suggest the administration of sodium channel blockers.
Collapse
Affiliation(s)
- Gia Melikishvili
- Department of Pediatrics, MediClubGeorgia Medical Center, Tbilisi, Georgia
| | | | - Svetlana Gataullina
- Services d'explorations fonctionnelles, Centre de médecine du sommeil, Hôpital Antoine-Béclère, AP-HP, Clamart, France; Service de pédiatrie, Centre hospitalier intercommunal André Grégoire, Montreuil, France.
| |
Collapse
|
17
|
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.
Collapse
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
| |
Collapse
|
18
|
Ekici A, Yılmaz İ, Görükmez O, Orcan CG, Dorum S. May PEHO Syndrome be a Clinical Entity Associated with Early Onset Encephalopathies? Ann Indian Acad Neurol 2020; 23:401-403. [PMID: 32606555 PMCID: PMC7313604 DOI: 10.4103/aian.aian_331_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 06/23/2019] [Accepted: 06/23/2019] [Indexed: 11/17/2022] Open
Affiliation(s)
- Arzu Ekici
- Department of Pediatric Neurology, University of Health Sciences, Bursa Yüksek Ihtisas Training and Research Hospital, Bursa, Turkey
| | - İlyas Yılmaz
- Department of Pediatrics, University of Health Sciences, Bursa Yüksek Ihtisas Training and Research Hospital, Bursa, Turkey
| | - Orhan Görükmez
- Department of Medical Genetics, University of Health Sciences, Bursa Yüksek Ihtisas Training and Research Hospital, Bursa, Turkey
| | - Cengiz Gökhan Orcan
- Department of Radiology, University of Health Sciences, Bursa Yüksek Ihtisas Training and Research Hospital, Bursa, Turkey
| | - Sevil Dorum
- Department of Metabolism, University of Health Sciences, Bursa Yüksek İhtisas Training and Research Hospital, Bursa, Turkey
| |
Collapse
|
19
|
Wolff M, Brunklaus A, Zuberi SM. Phenotypic spectrum and genetics of SCN2A-related disorders, treatment options, and outcomes in epilepsy and beyond. Epilepsia 2020; 60 Suppl 3:S59-S67. [PMID: 31904126 DOI: 10.1111/epi.14935] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 12/25/2022]
Abstract
Pathogenic variants in the SCN2A gene are associated with a variety of neurodevelopmental phenotypes, defined in recent years through multicenter collaboration. Phenotypes include benign (self-limited) neonatal and infantile epilepsy and more severe developmental and epileptic encephalopathies also presenting in early infancy. There is increasing evidence that an important phenotype linked to the gene is autism and intellectual disability without epilepsy or with rare seizures in later childhood. Other associations of SCN2A include the movement disorders chorea and episodic ataxia. It is likely that as genetic testing enters mainstream practice that new phenotypic associations will be identified. Some missense, gain of function variants tend to present in early infancy with epilepsy, whereas other missense or truncating, loss of function variants present with later-onset epilepsies or intellectual disability only. Knowledge of both mutation type and functional consequences can guide precision therapy. Sodium channel blockers may be effective antiepileptic medications in gain of function, neonatal and infantile presentations.
Collapse
Affiliation(s)
- Markus Wolff
- Pediatric Neurology, Vivantes Hospital Neukoelln, Berlin, Germany
| | - Andreas Brunklaus
- Paediatric Neurosciences Research Group, Royal Hospital for Children & School of Medicine, University of Glasgow, Glasgow, UK
| | - Sameer M Zuberi
- Paediatric Neurosciences Research Group, Royal Hospital for Children & School of Medicine, University of Glasgow, Glasgow, UK
| |
Collapse
|
20
|
Brunklaus A, Leu C, Gramm M, Pérez-Palma E, Iqbal S, Lal D. Time to move beyond genetics towards biomedical data-driven translational genomic research in severe paediatric epilepsies. Eur J Paediatr Neurol 2020; 24:35-39. [PMID: 31924506 DOI: 10.1016/j.ejpn.2019.12.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 12/06/2019] [Indexed: 11/18/2022]
Abstract
By accumulating ever greater amounts of genomic data, scientists have identified >100 genes associated with Mendelian forms of epilepsy and neurodevelopmental disorders with seizures. For most of the identified genes a wide range of genetic variants have been identified and affected patients are clinically heterogeneous. It is not clear to which degree the clinical heterogeneity can be attributed to the disease causing variant alone. We need to improve our current understanding of biophysical effects of variants on protein function and the role of polygenic background in modifying the clinical representation. In addition, longitudinal clinical data need to be recorded using standardized methods and shared across research centers to build large virtual cohorts for each single gene disorder. Without large, comprehensive, longitudinal datasets, studying the interplay of environmental factors and genetic factors will be challenging. As a community, we must work together to set the foundation for biorepositories and the collection and sharing of 'big data' in order to allow genetic-phenotypic characterization of the epilepsies and to fully utilize the potential for drug discovery, and patient-specific tailored management.
Collapse
Affiliation(s)
- Andreas Brunklaus
- The Paediatric Neurosciences Research Group, Royal Hospital for Children, Glasgow, G51 4TF, UK; School of Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Costin Leu
- Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Marie Gramm
- Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany
| | - Eduardo Pérez-Palma
- Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH, 44195, USA
| | - Sumaiya Iqbal
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, 02114, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Dennis Lal
- Genomic Medicine Institute, Lerner Research Institute Cleveland Clinic, Cleveland, OH, 44195, USA; Cologne Center for Genomics (CCG), University of Cologne, 50931, Cologne, Germany; Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, MA, 02114, USA; Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA; Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, 44195, USA.
| |
Collapse
|
21
|
Guerrini R, Parrini E, Esposito A, Fassio A, Conti V. Lesional and non-lesional epilepsies: A blurring genetic boundary. Eur J Paediatr Neurol 2020; 24:24-29. [PMID: 31875834 DOI: 10.1016/j.ejpn.2019.12.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/05/2019] [Accepted: 12/06/2019] [Indexed: 01/02/2023]
Abstract
There has been a traditional conceptual partition between the so-called non-lesional genetic epilepsies and the genetically determined interposed epileptogenic structural abnormalities. In this review, we summarise how growing evidence acquired through neuroimaging and neurobiology modelling is demonstrating that a distinction between lesional and functional (or non-lesional) epileptogenesis is less obvious than previously thought, particularly for epileptogenic neurodevelopmental disorders, but also for most genetically determined epilepsies.
Collapse
Affiliation(s)
- Renzo Guerrini
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital Anna Meyer-University of Florence, 50139, Florence, Italy.
| | - Elena Parrini
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital Anna Meyer-University of Florence, 50139, Florence, Italy
| | - Alessandro Esposito
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia, 16100, Genoa, Italy; Department of Experimental Medicine, University of Genoa, 16100, Genoa, Italy
| | - Anna Fassio
- Department of Experimental Medicine, University of Genoa, 16100, Genoa, Italy; IRCCS Ospedale Policlinico San Martino, 16100, Genoa, Italy
| | - Valerio Conti
- Paediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Children's Hospital Anna Meyer-University of Florence, 50139, Florence, Italy
| |
Collapse
|
22
|
Abstract
Zusammenfassung
Je nach Anfallssemiologie und EEG-Befund werden Epilepsien klinisch zumeist in fokale bzw. generalisierte Formen unterteilt. Tritt bei einem Kind infolge einer Epilepsie zusätzlich eine Entwicklungsstörung auf, kann dies oft auf eine epileptische Enzephalopathie zurückgeführt werden. Das Mutationsspektrum genetischer Epilepsien ist ausgesprochen heterogen und kann am besten mithilfe der Hochdurchsatzsequenzierung erfasst werden. Insbesondere bei den Enzephalopathien besteht eine hohe Aufklärungsrate. Mittlerweile gibt es für diverse genetisch bedingte Epilepsieerkrankungen individualisierte Therapien, die auf den jeweiligen molekularen Pathomechanismus abzielen, und die Zahl solcher personalisierter Therapieoptionen steigt stetig.
Collapse
Affiliation(s)
- Johannes R. Lemke
- 1 grid.411339.d 0000 0000 8517 9062 Institut für Humangenetik Universitätsklinikum Leipzig Ph.-Rosenthal-Str. 55 04103 Leipzig Deutschland
| |
Collapse
|
23
|
Vlachou V, Larsen L, Pavlidou E, Ismayilova N, Mazarakis ND, Scala M, Pantazi M, Mankad K, Kinali M. SCN2A mutation in an infant with Ohtahara syndrome and neuroimaging findings: expanding the phenotype of neuronal migration disorders. J Genet 2019; 98:54. [PMID: 31204721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Neuronal migration disorders (NMDs) are a heterogeneous group of conditions caused by the abnormal migration of neuroblasts in the developing brain and nervous system, resulting in severe developmental impairment, intractable epilepsy and intellectual disability (Spalice et al. 2009). To date, many genes have been identified as the leading cause of migration defects, i.e. agyria/pachygyria, polymicrogyria, heterotopias, agenesis of the corpus callosum and agenesis of the cranial nerves (Spalice et al. 2009). Here, we present a patient with early infantile epileptic encephalopathy (Ohtahara syndrome) with seizure onset on the first dayof life, severe developmental delay and an abnormal brain MRI with excessive folding of small, fused gyri and bilateral perisylvian polymicrogyria, suggestive of neuronal migration disorder. To clarify the unknown aetiology, we conducted whole-exome sequencing, which detected a de novo missense variant (c.5308A>T; p.(Met1770Leu)) in the SCN2A gene. This is a report of SCN2A gene variant identified in a patient with neuronal migration disorder which could further expand the phenotypic spectrum of these genetic disorders.
Collapse
Affiliation(s)
- Victoria Vlachou
- Department of Paediatric Neurology, Chelsea and Westminster NHS Foundation Trust, London SW10 9NH, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
SCN2A mutation in an infant with Ohtahara syndrome and neuroimaging findings: expanding the phenotype of neuronal migration disorders. J Genet 2019. [DOI: 10.1007/s12041-019-1104-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
25
|
Understanding the schizophrenia phenotype in the first patient with the full SCN2A phenotypic spectrum. Psychiatr Genet 2019; 29:91-94. [PMID: 30741786 DOI: 10.1097/ypg.0000000000000219] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The sodium voltage-gated channel α subunit 2 (SCN2A) gene encodes a subunit of sodium voltage-gated channels expressed primarily in the central nervous system that are responsible for action potential initiation and propagation in excitable cells. SCN2A mutations underlie a spectrum of distinct phenotypes, including seizure disorders, neurodevelopmental disorders, and rarer instances of episodic ataxia and schizophrenia. We report on a 38-year-old patient with adult-onset psychotic symptoms on a background of infantile-onset seizures, autistic features and episodic ataxia. Whole-exome sequencing revealed a de-novo novel SCN2A mutation (c.4966T > C, p.Ser1656Pro). This and other SCN2A mutations associated with the schizophrenia phenotype overlap those seen in neurodevelopmental disorders, suggesting a common underlying mechanism. This is the first report of a patient with the entire known SCN2A phenotypic spectrum. We highlight the importance of recognizing the psychiatric phenotypes associated with SCN2A mutations and that the phenotypic spectrum is more fluid, and less categorical, than previously thought.
Collapse
|
26
|
Syrbe S. Genetische epileptische Enzephalopathien des Säuglingsalters. ZEITSCHRIFT FÜR EPILEPTOLOGIE 2019. [DOI: 10.1007/s10309-018-0238-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
27
|
Orsini A, Zara F, Striano P. Recent advances in epilepsy genetics. Neurosci Lett 2018; 667:4-9. [DOI: 10.1016/j.neulet.2017.05.014] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Revised: 04/20/2017] [Accepted: 05/08/2017] [Indexed: 01/10/2023]
|