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Vranic-Peters M, O'Brien P, Seneviratne U, Reynolds A, Lai A, Grayden DB, Cook MJ, Peterson ADH. Response to photic stimulation as a measure of cortical excitability in epilepsy patients. Front Neurosci 2024; 17:1308013. [PMID: 38249581 PMCID: PMC10796504 DOI: 10.3389/fnins.2023.1308013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 12/12/2023] [Indexed: 01/23/2024] Open
Abstract
Studying states and state transitions in the brain is challenging due to nonlinear, complex dynamics. In this research, we analyze the brain's response to non-invasive perturbations. Perturbation techniques offer a powerful method for studying complex dynamics, though their translation to human brain data is under-explored. This method involves applying small inputs, in this case via photic stimulation, to a system and measuring its response. Sensitivity to perturbations can forewarn a state transition. Therefore, biomarkers of the brain's perturbation response or "cortical excitability" could be used to indicate seizure transitions. However, perturbing the brain often involves invasive intracranial surgeries or expensive equipment such as transcranial magnetic stimulation (TMS) which is only accessible to a minority of patient groups, or animal model studies. Photic stimulation is a widely used diagnostic technique in epilepsy that can be used as a non-invasive perturbation paradigm to probe brain dynamics during routine electroencephalography (EEG) studies in humans. This involves changing the frequency of strobing light, sometimes triggering a photo-paroxysmal response (PPR), which is an electrographic event that can be studied as a state transition to a seizure state. We investigate alterations in the response to these perturbations in patients with genetic generalized epilepsy (GGE), with (n = 10) and without (n = 10) PPR, and patients with psychogenic non-epileptic seizures (PNES; n = 10), compared to resting controls (n = 10). Metrics of EEG time-series data were evaluated as biomarkers of the perturbation response including variance, autocorrelation, and phase-based synchrony measures. We observed considerable differences in all group biomarker distributions during stimulation compared to controls. In particular, variance and autocorrelation demonstrated greater changes in epochs close to PPR transitions compared to earlier stimulation epochs. Comparison of PPR and spontaneous seizure morphology found them indistinguishable, suggesting PPR is a valid proxy for seizure dynamics. Also, as expected, posterior channels demonstrated the greatest change in synchrony measures, possibly reflecting underlying PPR pathophysiologic mechanisms. We clearly demonstrate observable changes at a group level in cortical excitability in epilepsy patients as a response to perturbation in EEG data. Our work re-frames photic stimulation as a non-invasive perturbation paradigm capable of inducing measurable changes to brain dynamics.
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Affiliation(s)
- Michaela Vranic-Peters
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
| | - Patrick O'Brien
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
| | - Udaya Seneviratne
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
| | - Ashley Reynolds
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
| | - Alan Lai
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
| | - David B. Grayden
- Department of Biomedical Engineering, The University of Melbourne, Melbourne, VIC, Australia
| | - Mark J. Cook
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
| | - Andre D. H. Peterson
- Department of Medicine, St Vincent's Hospital Melbourne, The University of Melbourne, Melbourne, VIC, Australia
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Zhang B, Chen T, Hao X, Xin M, Liang J. Electroclinical characteristics of photosensitive epilepsy: A retrospective study of 31 Chinese children and literature review. Front Pediatr 2023; 11:994817. [PMID: 36969295 PMCID: PMC10034115 DOI: 10.3389/fped.2023.994817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 01/27/2023] [Indexed: 03/29/2023] Open
Abstract
Objective The objective of this study was to better understand the clinical features of photosensitive epilepsy (PSE) in Chinese children. Methods Thirty-one children with PSE were screened out of 398 children with epilepsy who were consecutively diagnosed by the video-electroencephalogram (VEEG) monitoring method and by using an intermittent photic stimulation (IPS) test. Their EEGs and clinical features were retrospectively analyzed, and their treatment outcomes were followed up. Results PSE accounted for 7.79% (31/398) of children with epilepsy during the observation period in our single epilepsy center. The male to female ratio of PSE was 1:3.43, and the average seizure onset age was 7.8 ± 3.28 years. The highest range of frequency sensitivity of the IPS test for the induction of EEG epileptic discharge or electroclinical seizures was within 10-20 Hz. Electroclinical seizures were induced in 41.94% (13/31) of PSE patients by using the IPS test, while EEG discharge without clinical seizures was induced in 58.06% (18/31) of PSE patients. Among all PSE patients, an IPS-positive reaction in the eye-closure state was induced in 83.87% of patients, and this rate was significantly higher than that in the eye-opened state (41.94%) or eye-closed state (35.48%). (Eye-closure IPS stimulation means: make the subjects close their eyes at the beginning of each stimulation, open their eyes at the end of the stimulation, and close their eyes again at the beginning of the next stimulation, and so on. While Eye-closed IPS stimulation means the stimulation is started after 5 s of eye closure, and the subjects are kept closed throughout the whole process.) The common and effective drugs used for single or combined therapy in PSE children were valproic acid and levetiracetam. Conclusion This study provides some useful information about electroclinical characteristics in a cohort of 31 PSE children. It may be beneficial for pediatric neurologists in terms of paying more attention to PSE and correctly dealing with it.
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Affiliation(s)
- Bo Zhang
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Tianyu Chen
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Department of Pediatrics, The First Affiliated Hospital of Jinzhou Medical University, Jinzhou, China
| | - Xiaosheng Hao
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Meiying Xin
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
| | - Jianmin Liang
- Department of Pediatric Neurology, First Hospital of Jilin University, Changchun, China
- Jilin Provincial Key Laboratory of Pediatric Neurology, Changchun, China
- Correspondence: Jianmin Liang
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Fisher RS, Acharya JN, Baumer FM, French JA, Parisi P, Solodar JH, Szaflarski JP, Thio LL, Tolchin B, Wilkins AJ, Kasteleijn-Nolst Trenité D. Visually sensitive seizures: An updated review by the Epilepsy Foundation. Epilepsia 2022; 63:739-768. [PMID: 35132632 DOI: 10.1111/epi.17175] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/10/2022] [Accepted: 01/12/2022] [Indexed: 12/19/2022]
Abstract
Light flashes, patterns, or color changes can provoke seizures in up to 1 in 4000 persons. Prevalence may be higher because of selection bias. The Epilepsy Foundation reviewed light-induced seizures in 2005. Since then, images on social media, virtual reality, three-dimensional (3D) movies, and the Internet have proliferated. Hundreds of studies have explored the mechanisms and presentations of photosensitive seizures, justifying an updated review. This literature summary derives from a nonsystematic literature review via PubMed using the terms "photosensitive" and "epilepsy." The photoparoxysmal response (PPR) is an electroencephalography (EEG) phenomenon, and photosensitive seizures (PS) are seizures provoked by visual stimulation. Photosensitivity is more common in the young and in specific forms of generalized epilepsy. PS can coexist with spontaneous seizures. PS are hereditable and linked to recently identified genes. Brain imaging usually is normal, but special studies imaging white matter tracts demonstrate abnormal connectivity. Occipital cortex and connected regions are hyperexcitable in subjects with light-provoked seizures. Mechanisms remain unclear. Video games, social media clips, occasional movies, and natural stimuli can provoke PS. Virtual reality and 3D images so far appear benign unless they contain specific provocative content, for example, flashes. Images with flashes brighter than 20 candelas/m2 at 3-60 (particularly 15-20) Hz occupying at least 10 to 25% of the visual field are a risk, as are red color flashes or oscillating stripes. Equipment to assay for these characteristics is probably underutilized. Prevention of seizures includes avoiding provocative stimuli, covering one eye, wearing dark glasses, sitting at least two meters from screens, reducing contrast, and taking certain antiseizure drugs. Measurement of PPR suppression in a photosensitivity model can screen putative antiseizure drugs. Some countries regulate media to reduce risk. Visually-induced seizures remain significant public health hazards so they warrant ongoing scientific and regulatory efforts and public education.
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Affiliation(s)
- Robert S Fisher
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Jayant N Acharya
- Department of Neurology, Penn State Health, Hershey, Pennsylvania, USA
| | - Fiona Mitchell Baumer
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California, USA
| | - Jacqueline A French
- NYU Comprehensive Epilepsy Center, Epilepsy Foundation, New York, New York, USA
| | - Pasquale Parisi
- Department of Neuroscience, Mental Health, and Sensory Organs, Sapienza University, Rome, Italy
| | - Jessica H Solodar
- American Medical Writers Association-New England Chapter, Boston, Massachusetts, USA
| | - Jerzy P Szaflarski
- Department of Neurology, Neurobiology and Neurosurgery, University of Alabama at Birmingham Heersink School of Medicine, Birmingham, Alabama, USA
| | - Liu Lin Thio
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Benjamin Tolchin
- Department of Neurology, Yale School of Medicine, New Haven, Connecticut, USA
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Genetic generalized epilepsies in adults - challenging assumptions and dogmas. Nat Rev Neurol 2022; 18:71-83. [PMID: 34837042 DOI: 10.1038/s41582-021-00583-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2021] [Indexed: 01/16/2023]
Abstract
Genetic generalized epilepsy (GGE) syndromes start during childhood or adolescence, and four commonly persist into adulthood, making up 15-20% of all cases of epilepsy in adults. These four GGE syndromes are childhood absence epilepsy, juvenile absence epilepsy, juvenile myoclonic epilepsy and epilepsy with generalized tonic-clonic seizures alone. However, in ~20% of patients with GGE, characteristics of more than one syndrome are present. Novel insights into the genetic aetiology, comorbidities and prognosis of the GGE syndromes have emerged and challenge traditional concepts about these conditions. Evidence has shown that the mode of inheritance in GGE is mostly polygenic. Neuropsychological and imaging studies indicate similar abnormalities in unaffected relatives of patients with GGE, supporting the concept that underlying alterations in bilateral frontothalamocortical networks are genetically determined. Contrary to popular belief, first-line anti-seizure medication often fails to provide seizure freedom in combination with good tolerability. Nevertheless, long-term follow-up studies have shown that with advancing age, many patients can discontinue their anti-seizure medication without seizure relapses. Several outcome predictors have been identified, but prognosis across the syndromes is more homogeneous than previously assumed. Overall, overlap in pathophysiology, seizure types, treatment responses and outcomes support the idea that GGEs are not separate nosological entities but represent a neurobiological continuum.
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Iyer H, Wahul AB, P K A, Sawant BS, Kumar A. A BRD's (BiRD's) eye view of BET and BRPF bromodomains in neurological diseases. Rev Neurosci 2021; 32:403-426. [PMID: 33661583 DOI: 10.1515/revneuro-2020-0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 10/11/2020] [Indexed: 01/18/2023]
Abstract
Neurological disorders (NLDs) are among the top leading causes for disability worldwide. Dramatic changes in the epigenetic topography of the brain and nervous system have been found in many NLDs. Histone lysine acetylation has prevailed as one of the well characterised epigenetic modifications in these diseases. Two instrumental components of the acetylation machinery are the evolutionarily conserved Bromodomain and PHD finger containing (BRPF) and Bromo and Extra terminal domain (BET) family of proteins, also referred to as acetylation 'readers'. Several reasons, including their distinct mechanisms of modulation of gene expression and their property of being highly tractable small molecule targets, have increased their translational relevance. Thus, compounds which demonstrated promising results in targeting these proteins have advanced to clinical trials. They have been established as key role players in pathologies of cancer, cardiac diseases, renal diseases and rheumatic diseases. In addition, studies implicating the role of these bromodomains in NLDs are gaining pace. In this review, we highlight the findings of these studies, and reason for the plausible roles of all BET and BRPF members in NLDs. A comprehensive understanding of their multifaceted functions would be radical in the development of therapeutic interventions.
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Affiliation(s)
- Harish Iyer
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Abhipradnya B Wahul
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Annapoorna P K
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
| | - Bharvi S Sawant
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
| | - Arvind Kumar
- Epigenetics and Neuropsychiatric Disorders' Laboratory, CSIR - Centre for Cellular and Molecular Biology (CCMB), Hyderabad500007, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad201002, India
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Brinciotti M, Mittica A, Matricardi M. Characteristics of visual evoked potentials related to the electro-clinical expression of reflex seizures in photosensitive patients with idiopathic occipital lobe epilepsy. Epilepsy Res 2020; 164:106345. [DOI: 10.1016/j.eplepsyres.2020.106345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/30/2020] [Accepted: 04/22/2020] [Indexed: 11/24/2022]
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Atalar AÇ, Vanlı-Yavuz EN, Yılmaz E, Bebek N, Baykan B. Reflex epileptic features in patients with focal epilepsy of unknown cause. Clin Neurol Neurosurg 2019; 190:105633. [PMID: 31865219 DOI: 10.1016/j.clineuro.2019.105633] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 11/09/2019] [Accepted: 12/06/2019] [Indexed: 11/27/2022]
Abstract
OBJECTIVES There is a gap of knowledge regarding reflex seizures in patients with focal epilepsy of unknown cause (FEUC). We aimed to evaluate the prevalence, demographic and clinical characteristics of reflex seizures in patients with FEUC to provide an insight to the underlying ictogenic mechanisms and to draw attention to this important but under-investigated topic. PATIENTS AND METHODS After carefully questioning for reflex triggers, 186 patients diagnosed according to ILAE criteria and followed-up for a minimum of 5 years were included. The demographic and clinical properties as well as electrophysiological and neuroimaging data of these patients were reevaluated and compared to the patients without reflex seizures. RESULTS The reflex seizure rate was 6.5 % in patients with FEUC. Patients with reflex features had lower monotherapy rates (p = 0.005) and higher major depression rates (p = 0.001) than patients without reflex features. The distribution of the patients according to their reflex triggers were as follows: hot-water induced (n = 3, 25 %), photosensitive (n = 2, 16.7 %), eating- induced (n = 2, 16.7 %), musicogenic (n = 2, 16.7 %), startle induced (n = 2, 16.7 %) and both musicogenic and startle type (n = 1, 8.3 %) respectively. The drug resistance rate of patients with reflex seizures was 25 % (n = 3). One patient with drug resistant reflex seizures showed benefit from epilepsy surgery and became seizure-free during last 3 years of follow-up. CONCLUSION A careful and thoroughly history taking specifically questioning and focusing on seizure inducing factors in patients with FEUC is needed to confirm the presence of reflex seizures in patients with FEUC, who had higher rates of polytherapy and major depression. Elaborative evaluation of reflex features in FEUC might contribute to effective seizure control, ensure new therapeutic approaches, enlighten the obscurity and the resulting anxiety of having a diagnosis of FEUC in epilepsy patients.
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Affiliation(s)
- Arife Çimen Atalar
- Istanbul University, Istanbul Faculty of Medicine, Departments of Neurology and Clinical Neurophysiology Unit, Istanbul, Turkey; Istanbul Education and Research Hospital, Istanbul, Turkey.
| | - Ebru Nur Vanlı-Yavuz
- Istanbul University, Istanbul Faculty of Medicine, Departments of Neurology and Clinical Neurophysiology Unit, Istanbul, Turkey; Koc University Hospital, Department of Neurology, Istanbul, Turkey
| | - Ebru Yılmaz
- Istanbul University, Istanbul Faculty of Medicine, Department of Nuclear Medicine, Istanbul Turkey
| | - Nerses Bebek
- Istanbul University, Istanbul Faculty of Medicine, Departments of Neurology and Clinical Neurophysiology Unit, Istanbul, Turkey
| | - Betül Baykan
- Istanbul University, Istanbul Faculty of Medicine, Departments of Neurology and Clinical Neurophysiology Unit, Istanbul, Turkey
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Padmanaban V, Inati S, Ksendzovsky A, Zaghloul K. Clinical advances in photosensitive epilepsy. Brain Res 2019; 1703:18-25. [DOI: 10.1016/j.brainres.2018.07.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 06/21/2018] [Accepted: 07/26/2018] [Indexed: 12/12/2022]
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Koeleman BP. What do genetic studies tell us about the heritable basis of common epilepsy? Polygenic or complex epilepsy? Neurosci Lett 2018; 667:10-16. [DOI: 10.1016/j.neulet.2017.03.042] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 03/21/2017] [Accepted: 03/23/2017] [Indexed: 12/23/2022]
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10
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Photosensitivity and epilepsy: Current concepts and perspectives-A narrative review. Seizure 2017; 50:209-218. [PMID: 28532712 DOI: 10.1016/j.seizure.2017.04.001] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Revised: 03/31/2017] [Accepted: 04/04/2017] [Indexed: 01/15/2023] Open
Abstract
The authors review the influence of photic stimuli on the generation of epileptic seizures, addressing the first descriptions of the phenomenon and its subsequent exploration. Initially defined in the 1950's, links between intermittent photic stimulation (IPS) and seizures were well understood by the 1970. Since then the increasing exposure to photic stimuli associated with modern life (for instance through TVs, patterns, computer games and electronic instruments with flickering displays) has led to an increased interest in this issue. Diverse stimulation procedures have been described and difference in the effects of stimulation frequencies and types, colour and lighting have been recognised. Approximately 5% of patients with epilepsy have photosensitive epilepsy (PSE). PSE is commoner in younger individuals, more frequent in women, often time-limited, generally easy to treat and closely related to generalised epilepsies, especially Juvenile Myoclonic Epilepsy (JME). Structural and functional studies of PSE indicate abnormalities beyond the frontal lobes and evidence for the role of the visual cortex in human PSE. A reduction in connectivity between prefrontal and frontopolar regions and increased connectivity between occipital cortex and the supplementary motor area may be the basis for triggering motor seizures in JME. Due to the changes observed in such areas, it is hypothesised that photoparoxysmal responses (PPR) could be a final expression of pathogenic phenomena in the striato-thalamocortical system, and possibly a core feature of JME as system epilepsy. The familial transmission of epileptiform responses to IPS is well-recognised, but no clear relation between PSE and specific genes has emerged. Although the influence of ethnic factors on PSE has been widely studied, clear conclusions are still lacking. Pharmacological therapeutic approaches are beyond the scope of this review although preventive measures allowing patients to avoid PS seizure initiation and/or generalisation are discussed. Given the gender/age group most commonly affected by PSE, the risks and benefits of drug treatment need to be carefully weighed up.
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Verbeek N, Kasteleijn-Nolst Trenité D, Wassenaar M, van Campen J, Sonsma A, Gunning WB, de Weerd A, Knoers N, Spetgens W, Gutter T, Leijten F, Brilstra E. Photosensitivity in Dravet syndrome is under-recognized and related to prognosis. Clin Neurophysiol 2017; 128:323-330. [DOI: 10.1016/j.clinph.2016.11.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 10/27/2016] [Accepted: 11/24/2016] [Indexed: 11/25/2022]
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Marini S, Limongelli I, Rizzo E, Malovini A, Errichiello E, Vetro A, Da T, Zuffardi O, Bellazzi R. A Data Fusion Approach to Enhance Association Study in Epilepsy. PLoS One 2016; 11:e0164940. [PMID: 27984588 PMCID: PMC5161322 DOI: 10.1371/journal.pone.0164940] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 10/04/2016] [Indexed: 11/25/2022] Open
Abstract
Among the scientific challenges posed by complex diseases with a strong genetic component, two stand out. One is unveiling the role of rare and common genetic variants; the other is the design of classification models to improve clinical diagnosis and predictive models for prognosis and personalized therapies. In this paper, we present a data fusion framework merging gene, domain, pathway and protein-protein interaction data related to a next generation sequencing epilepsy gene panel. Our method allows integrating association information from multiple genomic sources and aims at highlighting the set of common and rare variants that are capable to trigger the occurrence of a complex disease. When compared to other approaches, our method shows better performances in classifying patients affected by epilepsy.
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Affiliation(s)
- Simone Marini
- Bioinformatics Center, Institute for Chemical Research, Kyoto University, Kyoto, Japan
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
- * E-mail: ,
| | - Ivan Limongelli
- Genomic Core Center, IRCCS Fondazione San Matteo, Pavia, Italy
- enGenome S.r.l., Via Ferrata 5, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Pavia, Italy
| | - Ettore Rizzo
- enGenome S.r.l., Via Ferrata 5, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Pavia, Italy
| | | | | | - Annalisa Vetro
- Genomic Core Center, IRCCS Fondazione San Matteo, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Tan Da
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
| | - Orsetta Zuffardi
- Genomic Core Center, IRCCS Fondazione San Matteo, Pavia, Italy
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Riccardo Bellazzi
- Department of Electrical, Computer and Biomedical Engineering, University of Pavia, Pavia, Italy
- Centre for Health Technologies, University of Pavia, Pavia, Italy
- IRCCS Fondazione S. Maugeri, Pavia, Italy
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Taoufiqi FZ, Mounach J, Satte A, Ouhabi H, El Hessni A. IPS Interest in the EEG of Patients after a Single Epileptic Seizure. NEUROSCIENCE JOURNAL 2016; 2016:5050278. [PMID: 27635393 PMCID: PMC5011226 DOI: 10.1155/2016/5050278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 06/10/2016] [Accepted: 06/29/2016] [Indexed: 11/18/2022]
Abstract
Objective. This study aims to evaluate the incidence of pathological cerebral activity responses to intermittent rhythmic photic stimulation (IPS) after a single epileptic seizure. Patients and Methods. One hundred and thirty-seven EEGs were performed at the Neurophysiology Department of Mohamed V Teaching Military Hospital in Rabat. Clinical and EEG data was collected. Results. 9.5% of our patients had photoparoxysmal discharges (PPD). Incidence was higher in males than in females, but p value was not significant (p = 0.34), and it was higher in children compared to adults with significant p value (p = 0.08). The most epileptogenic frequencies were within the range 15-20 Hz. 63 patients had an EEG after 72 hours; among them 11 were photosensitive (p = 0.001). The frequency of the PPR was significantly higher in patients with generalized abnormalities than in focal abnormalities (p = 0.001). EEG confirmed a genetic generalized epilepsy in 8 cases among 13 photosensitive patients. Conclusion. PPR is age related. The frequencies within the range 15-20 Hz should inevitably be included in EEG protocols. The presence of PPR after a first seizure is probably more in favor of generalized seizure rather than the other type of seizure. PPR seems independent from the delay Seizure-EEG. Our study did not show an association between sex and photosensitivity.
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Affiliation(s)
- Fatima Zahra Taoufiqi
- Unit of Nervous and Endocrine Physiology, Laboratory of Genetics and Neuroendocrine Physiology, Department of Biology, Faculty of Sciences, Ibn Tofail University, PB 133, 14000 Kenitra, Morocco
| | - Jamal Mounach
- Neurophysiology Department, Mohamed V Teaching Military Hospital, Rabat 10100, Morocco
| | - Amal Satte
- Neurophysiology Department, Mohamed V Teaching Military Hospital, Rabat 10100, Morocco
| | - Hamid Ouhabi
- Service of Neurology, Cheikh Khalifa Hospital, Casablanca 82403, Morocco
| | - Aboubaker El Hessni
- Unit of Nervous and Endocrine Physiology, Laboratory of Genetics and Neuroendocrine Physiology, Department of Biology, Faculty of Sciences, Ibn Tofail University, PB 133, 14000 Kenitra, Morocco
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Italiano D, Striano P, Russo E, Leo A, Spina E, Zara F, Striano S, Gambardella A, Labate A, Gasparini S, Lamberti M, De Sarro G, Aguglia U, Ferlazzo E. Genetics of reflex seizures and epilepsies in humans and animals. Epilepsy Res 2016; 121:47-54. [PMID: 26875109 DOI: 10.1016/j.eplepsyres.2016.01.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Revised: 01/22/2016] [Accepted: 01/29/2016] [Indexed: 01/12/2023]
Abstract
INTRODUCTION Reflex seizures are epileptic events triggered by specific motor, sensory or cognitive stimulation. This comprehensive narrative review focuses on the role of genetic determinants in humans and animal models of reflex seizures and epilepsies. METHODS References were mainly identified through MEDLINE searches until August 2015 and backtracking of references in pertinent studies. RESULTS Autosomal dominant inheritance with reduced penetrance was proven in several families with photosensitivity. Molecular genetic studies on EEG photoparoxysmal response identified putative loci on chromosomes 6, 7, 13 and 16 that seem to correlate with peculiar seizure phenotype. No specific mutation has been found in Papio papio baboon, although a genetic etiology is likely. Mutation in synaptic vesicle glycoprotein 2A was found in another animal model of photosensitivity (Fayoumi chickens). Autosomal dominant inheritance with incomplete penetrance overlapping with a genetic background for IGE was proposed for some families with primary reading epilepsy. Musicogenic seizures usually occur in patients with focal symptomatic or cryptogenic epilepsies, but they have been reported in rare genetic epilepsies such as Dravet syndrome. A single LGI1 mutation has been described in a girl with seizures evoked by auditory stimuli. Interestingly, heterozygous knockout (Lgi1(+/-)) mice show susceptibility to sound-triggered seizures. Moreover, in Frings and Black Swiss mice, the spontaneous mutations of MASS1 and JAMS1 genes, respectively, have been linked to audiogenic seizures. Eating seizures usually occur in symptomatic epilepsies but evidences for a genetic susceptibility were mainly provided by family report from Sri Lanka. Eating seizures were also reported in rare patients with MECP2 duplication or mutation. Hot water seizures are genetically heterogeneous but two loci at chromosomes 4 and 10 were identified in families with likely autosomal dominant inheritance. Startle-induced seizures usually occur in patients with symptomatic epilepsies but have also been reported in the setting chromosomal disorders or genetically inherited lysosomal storage diseases. DISCUSSION The genetic background of reflex seizures and epilepsies is heterogeneous and mostly unknown with no major gene identified in humans. The benefits offered by next-generation sequencing technologies should be merged with increasing information on animal models that represent an useful tool to study the mechanism underlying epileptogenesis. Finally, we expect that genetic studies will lead to a better understanding of the multiple factors involved in the pathophysiology of reflex seizures, and eventually to develop preventive strategies focused on seizure control and therapy optimization.
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Affiliation(s)
- Domenico Italiano
- Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria, 1, Messina, Italy
| | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
| | - Emilio Russo
- Science of Health Department, School of Medicine, University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Antonio Leo
- Science of Health Department, School of Medicine, University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Edoardo Spina
- Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria, 1, Messina, Italy
| | - Federico Zara
- Laboratory of Neurogenetics and Neurosciences, Department of Neurosciences, "G. Gaslini" Institute, Genova, Italy
| | - Salvatore Striano
- Epilepsy Center, Department of Neurosciences, Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - Antonio Gambardella
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy
| | - Angelo Labate
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy
| | - Sara Gasparini
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
| | - Marco Lamberti
- Department of Clinical and Experimental Medicine, University of Messina, Via Consolare Valeria, 1, Messina, Italy
| | - Giovambattista De Sarro
- Science of Health Department, School of Medicine, University of Catanzaro, Viale Europa, Catanzaro, Italy
| | - Umberto Aguglia
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy.
| | - Edoardo Ferlazzo
- Department of Medical and Surgical Sciences, Magna Graecia University of Catanzaro, Viale Europa, Catanzaro, Italy; Institute of Molecular Bioimaging and Physiology of the National Research Council (IBFM-CNR), Viale Europa, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
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15
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Wight JE, Nguyen VH, Medina MT, Patterson C, Durón RM, Molina Y, Lin YC, Martínez-Juárez IE, Ochoa A, Jara-Prado A, Tanaka M, Bai D, Aftab S, Bailey JN, Delgado-Escueta AV. Chromosome loci vary by juvenile myoclonic epilepsy subsyndromes: linkage and haplotype analysis applied to epilepsy and EEG 3.5-6.0 Hz polyspike waves. Mol Genet Genomic Med 2016; 4:197-210. [PMID: 27066514 PMCID: PMC4799870 DOI: 10.1002/mgg3.195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 11/09/2015] [Accepted: 11/12/2015] [Indexed: 12/15/2022] Open
Abstract
Juvenile myoclonic epilepsy (JME), the most common genetic epilepsy, remains enigmatic because it is considered one disease instead of several diseases. We ascertained three large multigenerational/multiplex JME pedigrees from Honduras with differing JME subsyndromes, including Childhood Absence Epilepsy evolving to JME (CAE/JME; pedigree 1), JME with adolescent onset pyknoleptic absence (JME/pA; pedigree 2), and classic JME (cJME; pedigree 3). All phenotypes were validated, including symptomatic persons with various epilepsies, asymptomatic persons with EEG 3.5-6.0 Hz polyspike waves, and asymptomatic persons with normal EEGs. Two-point parametric linkage analyses were performed with 5185 single-nucleotide polymorphisms on individual pedigrees and pooled pedigrees using four diagnostic models based on epilepsy/EEG diagnoses. Haplotype analyses of the entire genome were also performed for each individual. In pedigree 1, haplotyping identified a 34 cM region in 2q21.2-q31.1 cosegregating with all affected members, an area close to 2q14.3 identified by linkage (Z max = 1.77; pedigree 1). In pedigree 2, linkage and haplotyping identified a 44 cM cosegregating region in 13q13.3-q31.2 (Z max = 3.50 at 13q31.1; pooled pedigrees). In pedigree 3, haplotyping identified a 6 cM cosegregating region in 17q12. Possible cosegregation was also identified in 13q14.2 and 1q32 in pedigree 3, although this could not be definitively confirmed due to the presence of uninformative markers in key individuals. Differing chromosome regions identified in specific JME subsyndromes may contain separate JME disease-causing genes, favoring the concept of JME as several distinct diseases. Whole-exome sequencing will likely identify a CAE/JME gene in 2q21.2-2q31.1, a JME/pA gene in 13q13.3-q31.2, and a cJME gene in 17q12.
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Affiliation(s)
- Jenny E Wight
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia
| | - Viet-Huong Nguyen
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia
| | - Marco T Medina
- GENESS International ConsortiumLos AngelesCalifornia; National Autonomous University of HondurasTegucigalpaHonduras
| | - Christopher Patterson
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia
| | - Reyna M Durón
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia; National Autonomous University of HondurasTegucigalpaHonduras; Universidad Tecnológica Centroamericana (UNITEC)TegucigalpaHonduras; Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Yolly Molina
- GENESS International ConsortiumLos AngelesCalifornia; National Autonomous University of HondurasTegucigalpaHonduras
| | - Yu-Chen Lin
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia
| | - Iris E Martínez-Juárez
- GENESS International ConsortiumLos AngelesCalifornia; National Institute of Neurology and NeurosurgeryMexico CityMexico
| | - Adriana Ochoa
- GENESS International ConsortiumLos AngelesCalifornia; National Institute of Neurology and NeurosurgeryMexico CityMexico
| | - Aurelio Jara-Prado
- GENESS International ConsortiumLos AngelesCalifornia; National Institute of Neurology and NeurosurgeryMexico CityMexico
| | - Miyabi Tanaka
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia; Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Dongsheng Bai
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia; Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Sumaya Aftab
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia; Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Julia N Bailey
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia; Department of EpidemiologyFielding School of Public Health at UCLALos AngelesCalifornia
| | - Antonio V Delgado-Escueta
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS - West Los AngelesLos AngelesCalifornia; GENESS International ConsortiumLos AngelesCalifornia; Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
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16
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Brinciotti M, Matricardi M. Paroxysmal eyelid movements in patients with visual‐sensitive reflex seizures. Epileptic Disord 2015; 17:372-383. [DOI: 10.1684/epd.2015.0773] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractAim. Paroxysmal eyelid movements (PEM) are non‐epileptic episodes characterized by eyelid closure, upturning of the eyes, and rapid eyelid flutter. The aim of this study was to report clinical and EEG data of patients with PEM and its relationship with visual sensitivity.Methods. We studied 26 patients with epilepsy (12 males and 14 females; mean age: 14.0±6.9 years) who presented PEM. The epilepsy was idiopathic generalized (eight cases), idiopathic focal (six cases), symptomatic focal (five cases), and reflex epilepsy (seven cases). PEM and blinking were analysed by video‐EEG recordings at rest and during intermittent photic stimulation, pattern stimulation, and TV watching. Blink rate was evaluated during three different conditions: at rest, during a TV‐viewing period, and at the occurrence of PEM. Analysis of variance (ANOVA) was used for statistical comparisons.Results. Repeated episodes of PEM were recorded in all patients. The frequency of PEM ranged from 8 to 12.5 Hz (average: 9.6±1.5). PEM were accompanied by a significant increase in blinking compared to the rest condition and TV watching (blink rate: 56.5±21.1 vs 25.0±16.2 vs 11.3±11.8, respectively; p<0.0001). Photoparoxysmal EEG responses (measured as sensitivity to photic stimulation) were found in 25 cases, associated with pattern sensitivity in 22; only one patient was sensitive to pattern but not photic stimulation. Visually‐induced seizures were recorded in 20 cases, triggered by both stimuli (photic and pattern stimulation) in 11 patients; seizures were triggered by pattern stimulation (but not photic stimulation) in five, photic stimulation (but not pattern stimulation) in three, and TV watching (but not photic or pattern stimulation) in one. Epileptic eyelid myoclonia was noted in 17 patients.Conclusion. The coexistence of PEM, photoparoxysmal EEG responses, increased blinking, and epileptic eyelid myoclonia suggests an underlying dysfunction involving cortical‐subcortical neural networks, according to the recent concept of system epilepsies. [Published with video sequences]
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Affiliation(s)
- Mario Brinciotti
- Department of Pediatrics and Child Neuropsychiatry, Interdepartmental Research Centre for Social Diseases (CIMS), Childhood Epilepsy Section, Faculty of Medicine and Dentistry Sapienza University of Rome Rome Italy
| | - Maria Matricardi
- Department of Pediatrics and Child Neuropsychiatry, Interdepartmental Research Centre for Social Diseases (CIMS), Childhood Epilepsy Section, Faculty of Medicine and Dentistry Sapienza University of Rome Rome Italy
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17
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Koepp MJ, Caciagli L, Pressler RM, Lehnertz K, Beniczky S. Reflex seizures, traits, and epilepsies: from physiology to pathology. Lancet Neurol 2015; 15:92-105. [PMID: 26627365 DOI: 10.1016/s1474-4422(15)00219-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 08/11/2015] [Accepted: 08/13/2015] [Indexed: 10/22/2022]
Abstract
Epileptic seizures are generally unpredictable and arise spontaneously. Patients often report non-specific triggers such as stress or sleep deprivation, but only rarely do seizures occur as a reflex event, in which they are objectively and consistently modulated, precipitated, or inhibited by external sensory stimuli or specific cognitive processes. The seizures triggered by such stimuli and processes in susceptible individuals can have different latencies. Once seizure-suppressing mechanisms fail and a critical mass (the so-called tipping point) of cortical activation is reached, reflex seizures stereotypically manifest with common motor features independent of the physiological network involved. The complexity of stimuli increases from simple sensory to complex cognitive-emotional with increasing age of onset. The topography of physiological networks involved follows the posterior-to-anterior trajectory of brain development, reflecting age-related changes in brain excitability. Reflex seizures and traits probably represent the extremes of a continuum, and understanding of their underlying mechanisms might help to elucidate the transition of normal physiological function to paroxysmal epileptic activity.
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Affiliation(s)
- Matthias J Koepp
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, UK.
| | - Lorenzo Caciagli
- Department of Clinical and Experimental Epilepsy, University College London (UCL) Institute of Neurology, London, UK; National Hospital for Neurology and Neurosurgery, Queen Square, UK
| | - Ronit M Pressler
- Department of Clinical Neurophysiology, Great Ormond Street Hospital, London, UK; Clinical Neuroscience, UCL Institute of Child Health, London, UK
| | - Klaus Lehnertz
- Department of Epileptology, University Hospital of Bonn, Bonn, Germany
| | - Sándor Beniczky
- Department of Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund, Denmark; Department of Clinical Neurophysiology, Aarhus University, Aarhus, Denmark
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18
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Investigation of the possible association of NEDD4-2 (NEDD4L) gene with idiopathic photosensitive epilepsy. Acta Neurol Belg 2015; 115:241-5. [PMID: 25542253 DOI: 10.1007/s13760-014-0412-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
Abstract
NEDD4-2 alias NEDD4L (neural precursor cell expressed, developmentally downregulated) gene was reported as a candidate gene for epileptic photo-sensitivity. We aimed to investigate this possible association of NEDD4-2 variants with idiopathic photosensitive epilepsy. Consecutive patients who had been followed up at our epilepsy center and diagnosed with idiopathic epilepsy according to ILAE criteria and clear-cut photoparoxysmal responses in their electroencephalograms and 100 ethnically matched healthy subjects were included in the study. The regions around previously reported three variants, namely, S233L, E271A and H515P were tracked with DHPLC and the samples showing variations were sequenced. 81 patients (63 females) aged between 12-63 years (45 had juvenile myoclonic epilepsy, 11 childhood absence epilepsy, 14 juvenile absence epilepsy, 7 late onset idiopathic generalized epilepsy, 1 unclassified idiopathic generalized epilepsy, and 3 patients with idiopathic photosensitive occipital lobe epilepsy) were included in this study. We found only one heterozygous S233L variant in a 23-year-old man who has photosensitive form of juvenile absence epilepsy and pattern sensitivity to striped carpets. Other two variants were not found in any of the other patients and controls. Our results suggest that three screened NEDD4-2 variants do not play a leading role in the pathogenesis of photosensitive epilepsy in the Turkish population.
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Kasteleijn-Nolst Trenité DGA, Volkers L, Strengman E, Schippers HM, Perquin W, de Haan GJ, Gkountidi AO, van't Slot R, van de Graaf SF, de Graaf SF, Jocic-Jakubi B, Capovilla G, Covanis A, Parisi P, Veggiotti P, Brinciotti M, Incorpora G, Piccioli M, Cantonetti L, Berkovic SF, Scheffer IE, Brilstra EH, Sonsma ACM, Bader AJ, de Kovel CGF, Koeleman BPC. Clinical and genetic analysis of a family with two rare reflex epilepsies. Seizure 2015; 29:90-6. [PMID: 26076849 DOI: 10.1016/j.seizure.2015.03.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 03/26/2015] [Accepted: 03/30/2015] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To determine clinical phenotypes, evolution and genetic background of a large family with a combination of two unusual forms of reflex epilepsies. METHOD Phenotyping was performed in eighteen family members (10 F, 8 M) including standardized EEG recordings with intermittent photic stimulation (IPS). Genetic analyses (linkage scans, Whole Exome Sequencing (WES) and Functional studies) were performed using photoparoxysmal EEG responses (PPRs) as affection status. RESULTS The proband suffered from speaking induced jaw-jerks and increasing limb jerks evoked by flickering sunlight since about 50 years of age. Three of her family members had the same phenotype. Generalized PPRs were found in seven members (six above 50 years of age) with myoclonus during the PPR. Evolution was typical: Sensitivity to lights with migraine-like complaints around adolescence, followed by jerks evoked by lights and spontaneously with dropping of objects, and strong increase of light sensitivity and onset of talking induced jaw jerks around 50 years. Linkage analysis showed suggestive evidence for linkage to four genomic regions. All photosensitive family members shared a heterozygous R129C mutation in the SCNM1 gene that regulates splicing of voltage gated ion channels. Mutation screening of 134 unrelated PPR patients and 95 healthy controls, did not replicate these findings. CONCLUSION This family presents a combination of two rare reflex epilepsies. Genetic analysis favors four genomic regions and points to a shared SCNM1 mutation that was not replicated in a general cohort of photosensitive subjects. Further genetic studies in families with similar combination of features are warranted.
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Affiliation(s)
- Dorothée G A Kasteleijn-Nolst Trenité
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands; Sapienza University, Pediatrics, Child Neurology, Rome, Italy.
| | - Linda Volkers
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | - Eric Strengman
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | | | - Willem Perquin
- Bronovo Ziekenhuis, Neurology, The Hague, The Netherlands
| | | | - Anastasia O Gkountidi
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | - Ruben van't Slot
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | - Stan F van de Graaf
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | | | | | | | | | - Pasquale Parisi
- Sapienza University, Pediatrics, Child Neurology, Rome, Italy
| | - Pierangelo Veggiotti
- Fondazione Istituto Neurologico Casimiro Mondino, Child Neuropsychiatry, Pavia, Italy
| | - Mario Brinciotti
- Sapienza University of Rome, Pediatrics and Child Neuropsychiatry, Rome, Italy
| | | | | | | | - Samuel F Berkovic
- Epilepsy Research Institute, Medicine (Neurology), Melbourne, Australia
| | - Ingrid E Scheffer
- Epilepsy Research Institute, Medicine (Neurology), Melbourne, Australia
| | - Eva H Brilstra
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | - Anja C M Sonsma
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | - Adri J Bader
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | - Carolien G F de Kovel
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
| | - Bobby P C Koeleman
- University Utrecht, Biomedical Genetics and Complex Genetics, Utrecht, The Netherlands
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20
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Galizia EC, Myers CT, Leu C, de Kovel CGF, Afrikanova T, Cordero-Maldonado ML, Martins TG, Jacmin M, Drury S, Krishna Chinthapalli V, Muhle H, Pendziwiat M, Sander T, Ruppert AK, Møller RS, Thiele H, Krause R, Schubert J, Lehesjoki AE, Nürnberg P, Lerche H, Palotie A, Coppola A, Striano S, Gaudio LD, Boustred C, Schneider AL, Lench N, Jocic-Jakubi B, Covanis A, Capovilla G, Veggiotti P, Piccioli M, Parisi P, Cantonetti L, Sadleir LG, Mullen SA, Berkovic SF, Stephani U, Helbig I, Crawford AD, Esguerra CV, Kasteleijn-Nolst Trenité DGA, Koeleman BPC, Mefford HC, Scheffer IE, Sisodiya SM. CHD2 variants are a risk factor for photosensitivity in epilepsy. Brain 2015; 138:1198-207. [PMID: 25783594 PMCID: PMC4407192 DOI: 10.1093/brain/awv052] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/07/2015] [Indexed: 12/24/2022] Open
Abstract
Photosensitivity in epilepsy is common and has high heritability, but its genetic basis remains uncertain. Galizia et al. reveal an overrepresentation of unique variants of CHD2 — which encodes the transcriptional regulator ‘chromodomain helicase DNA-binding protein 2’ — in photosensitive epilepsies, and show that chd2 knockdown in zebrafish causes photosensitivity. Photosensitivity is a heritable abnormal cortical response to flickering light, manifesting as particular electroencephalographic changes, with or without seizures. Photosensitivity is prominent in a very rare epileptic encephalopathy due to de novo CHD2 mutations, but is also seen in epileptic encephalopathies due to other gene mutations. We determined whether CHD2 variation underlies photosensitivity in common epilepsies, specific photosensitive epilepsies and individuals with photosensitivity without seizures. We studied 580 individuals with epilepsy and either photosensitive seizures or abnormal photoparoxysmal response on electroencephalography, or both, and 55 individuals with photoparoxysmal response but no seizures. We compared CHD2 sequence data to publicly available data from 34 427 individuals, not enriched for epilepsy. We investigated the role of unique variants seen only once in the entire data set. We sought CHD2 variants in 238 exomes from familial genetic generalized epilepsies, and in other public exome data sets. We identified 11 unique variants in the 580 individuals with photosensitive epilepsies and 128 unique variants in the 34 427 controls: unique CHD2 variation is over-represented in cases overall (P = 2·17 × 10−5). Among epilepsy syndromes, there was over-representation of unique CHD2 variants (3/36 cases) in the archetypal photosensitive epilepsy syndrome, eyelid myoclonia with absences (P = 3·50 × 10−4). CHD2 variation was not over-represented in photoparoxysmal response without seizures. Zebrafish larvae with chd2 knockdown were tested for photosensitivity. Chd2 knockdown markedly enhanced mild innate zebrafish larval photosensitivity. CHD2 mutation is the first identified cause of the archetypal generalized photosensitive epilepsy syndrome, eyelid myoclonia with absences. Unique CHD2 variants are also associated with photosensitivity in common epilepsies. CHD2 does not encode an ion channel, opening new avenues for research into human cortical excitability.
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Affiliation(s)
- Elizabeth C Galizia
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | | | - Costin Leu
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | - Carolien G F de Kovel
- 4 Department of Medical Genetics Research, University Medical Centre Utrecht, The Netherlands
| | - Tatiana Afrikanova
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | | | - Teresa G Martins
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Maxime Jacmin
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Suzanne Drury
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - V Krishna Chinthapalli
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | - Hiltrud Muhle
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Manuela Pendziwiat
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Thomas Sander
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | | | - Rikke S Møller
- 9 Danish Epilepsy Centre, Dianalund, Denmark 10 Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Holger Thiele
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | - Roland Krause
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Julian Schubert
- 11 Deptartment of Neurology and Epileptology, Hertie Institut for Clinical Brain Research, Tübingen, Germany
| | - Anna-Elina Lehesjoki
- 12 Folkhälsan Institute of Genetics and Neuroscience Centre, University of Helsinki, Helsinki, Finland 13 Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Peter Nürnberg
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | - Holger Lerche
- 11 Deptartment of Neurology and Epileptology, Hertie Institut for Clinical Brain Research, Tübingen, Germany
| | | | - Aarno Palotie
- 14 Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, UK 15 Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland 16 Program in Medical and Population Genetics and Genetic Analysis Platform, The Broad Institute of MIT and Harvard, Cambridge, USA
| | - Antonietta Coppola
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Salvatore Striano
- 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Luigi Del Gaudio
- 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Christopher Boustred
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Amy L Schneider
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
| | - Nicholas Lench
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Bosanka Jocic-Jakubi
- 19 Department of Child Neurology, Paediatric Clinic, Clinical Centre Nis, Serbia 20 Department of Paediatric Neurology, Paediatric Clinic, Al Sabah Hospital, Kuwait
| | - Athanasios Covanis
- 21 Neurology Department, The Children's Hospital Agia Sophia, Athens, Greece
| | | | - Pierangelo Veggiotti
- 23 Department of Child Neurology and Psychiatry C. Mondino National Neurological Institute, Via Mondino, 2, 27100, Pavia, Italy 24 Brain and Behaviour Department, University of Pavia, Pavia, Italy
| | - Marta Piccioli
- 25 Neurophysiopathology Unit, San Filippo Neri Hospital, Rome, Italy
| | - Pasquale Parisi
- 26 Child Neurology, NESMOS Department, Faculty of Medicine and Psychology, Sapienza University, Rome, Italy
| | - Laura Cantonetti
- 27 Neurorehabilitation Unit, Department of Neuroscience and Neurorehabilitation, IRCCS, Bambino Gesu' Children's Hospital, Rome, Italy
| | - Lynette G Sadleir
- 28 Department of Paediatrics and Child Health, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
| | - Saul A Mullen
- 29 Florey Institute of Neurosciences and Mental Health, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia
| | - Samuel F Berkovic
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
| | - Ulrich Stephani
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Ingo Helbig
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Alexander D Crawford
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Camila V Esguerra
- 30 Chemical Neuroscience Group, Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway 31 Laboratory for Molecular Biodiscovery, University of Leuven, Leuven, Belgium
| | | | - Bobby P C Koeleman
- 4 Department of Medical Genetics Research, University Medical Centre Utrecht, The Netherlands
| | | | - Ingrid E Scheffer
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia 29 Florey Institute of Neurosciences and Mental Health, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia
| | - Sanjay M Sisodiya
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
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Irmen F, Wehner T, Lemieux L. Do reflex seizures and spontaneous seizures form a continuum? - triggering factors and possible common mechanisms. Seizure 2014; 25:72-9. [PMID: 25645641 DOI: 10.1016/j.seizure.2014.12.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 12/06/2014] [Accepted: 12/14/2014] [Indexed: 11/26/2022] Open
Abstract
Recent changes in the understanding and classification of reflex seizures have fuelled a debate on triggering mechanisms of seizures and their conceptual organization. Previous studies and patient reports have listed extrinsic and intrinsic triggers, albeit their multifactorial and dynamic nature is poorly understood. This paper aims to review literature on extrinsic and intrinsic seizure triggers and to discuss common mechanisms among them. Among self-reported seizure triggers, emotional stress is most frequently named. Reflex seizures are typically associated with extrinsic sensory triggers; however, intrinsic cognitive or proprioceptive triggers have also been assessed. The identification of a trigger underlying a seizure may be more difficult if it is intrinsic and complex, and if triggering mechanisms are multifactorial. Therefore, since observability of triggers varies and triggers are also found in non-reflex seizures, the present concept of reflex seizures may be questioned. We suggest the possibility of a conceptual continuum between reflex and spontaneous seizures rather than a dichotomy and discuss evidence to the notion that to some extent most seizures might be triggered.
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Affiliation(s)
- Friederike Irmen
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, United Kingdom
| | - Tim Wehner
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, United Kingdom; National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Foundation Trust, London, United Kingdom
| | - Louis Lemieux
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, United Kingdom.
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22
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Italiano D, Ferlazzo E, Gasparini S, Spina E, Mondello S, Labate A, Gambardella A, Aguglia U. Generalized versus partial reflex seizures: a review. Seizure 2014; 23:512-20. [PMID: 24766826 DOI: 10.1016/j.seizure.2014.03.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 03/24/2014] [Indexed: 11/30/2022] Open
Abstract
In this review we assess our currently available knowledge about reflex seizures with special emphasis on the difference between "generalized" reflex seizures induced by visual stimuli, thinking, praxis and language tasks, and "focal" seizures induced by startle, eating, music, hot water, somatosensory stimuli and orgasm. We discuss in particular evidence from animal, clinical, neurophysiological and neuroimaging studies supporting the concept that "generalized" reflex seizures, usually occurring in the setting of IGE, should be considered as focal seizures with quick secondary generalization. We also review recent advances in genetic and therapeutic approach of reflex seizures.
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Affiliation(s)
- Domenico Italiano
- Department of Clinical and Experimental Medicine, University of Messina, Italy
| | - Edoardo Ferlazzo
- Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy.
| | - Sara Gasparini
- Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy
| | - Edoardo Spina
- Department of Clinical and Experimental Medicine, University of Messina, Italy
| | | | - Angelo Labate
- Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy
| | - Antonio Gambardella
- Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy; National Research Council, Piano Lago di Mangone, Cosenza, Italy
| | - Umberto Aguglia
- Department of Medical and Surgical Sciences, Magna Graecia University, Catanzaro, Italy; Regional Epilepsy Centre, Bianchi-Melacrino-Morelli Hospital, Reggio Calabria, Italy
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23
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Abstract
PURPOSE OF REVIEW We aim to review the most recent advances in the field of epilepsy genetics with particular focus on the progress in gene discovery in monogenic epilepsies, identification of risk genes in complex genetic epilepsies and recent findings in the field of epilepsy pharmacogenomics. RECENT FINDINGS During the last 12 months, the use of massive parallel sequencing technologies has allowed for the discovery of several genes for monogenic epilepsies. Most importantly, PRRT2 was identified as the long-sought gene for benign familial infantile seizures. Mutations in KCNT1 were found in two seemingly unrelated monogenic epilepsies including malignant migrating partial seizures of infancy and severe autosomal dominant nocturnal frontal lobe epilepsy. A genome-wide association study in idiopathic generalized epilepsy revealed the first common risk variants for human seizure disorders including variants in VRK2, PNPO and SCN1A. Furthermore, a landmark study provided evidence that screening for the HLA-B1502 variant may prevent carbamazepine CBZ-induced side effects in the Taiwanese population. Also, HLA-A3101 variants were identified as a risk factor for carbamazepine side effects in Europeans. SUMMARY Novel technologies and an unprecedented level of international collaboration have resulted in identification of novel genes for monogenic and complex genetic epilepsies as well as risk factors for side effects of antiepileptic drugs. This review provides an overview of the most relevant studies in the last year and highlights the future direction of the field.
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24
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Wojcik SM, Tantra M, Stepniak B, Man KNM, Müller-Ribbe K, Begemann M, Ju A, Papiol S, Ronnenberg A, Gurvich A, Shin Y, Augustin I, Brose N, Ehrenreich H. Genetic markers of a Munc13 protein family member, BAIAP3, are gender specifically associated with anxiety and benzodiazepine abuse in mice and humans. Mol Med 2013; 19:135-48. [PMID: 23698091 DOI: 10.2119/molmed.2013.00033] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/14/2013] [Indexed: 01/02/2023] Open
Abstract
Anxiety disorders and substance abuse, including benzodiazepine use disorder, frequently occur together. Unfortunately, treatment of anxiety disorders still includes benzodiazepines, and patients with an existing comorbid benzodiazepine use disorder or a genetic susceptibility for benzodiazepine use disorder may be at risk of adverse treatment outcomes. The identification of genetic predictors for anxiety disorders, and especially for benzodiazepine use disorder, could aid the selection of the best treatment option and improve clinical outcomes. The brain-specific angiogenesis inhibitor I-associated protein 3 (Baiap3) is a member of the mammalian uncoordinated 13 (Munc13) protein family of synaptic regulators of neurotransmitter exocytosis, with a striking expression pattern in amygdalae, hypothalamus and periaqueductal gray. Deletion of Baiap3 in mice leads to enhanced seizure propensity and increased anxiety, with the latter being more pronounced in female than in male animals. We hypothesized that genetic variation in human BAIAP3 may also be associated with anxiety. By using a phenotype-based genetic association study, we identified two human BAIAP3 single-nucleotide polymorphism risk genotypes (AA for rs2235632, TT for rs1132358) that show a significant association with anxiety in women and, surprisingly, with benzodiazepine abuse in men. Returning to mice, we found that male, but not female, Baiap3 knockout (KO) mice develop tolerance to diazepam more quickly than control animals. Analysis of cultured Baiap3 KO hypothalamus slices revealed an increase in basal network activity and an altered response to diazepam withdrawal. Thus, Baiap3/BAIAP3 is gender specifically associated with anxiety and benzodiazepine use disorder, and the analysis of Baiap3/BAIAP3-related functions may help elucidate mechanisms underlying the development of both disorders.
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Affiliation(s)
- Sonja M Wojcik
- Max Planck Institute of Experimental Medicine, Department of Molecular Neurobiology, Göttingen, Germany.
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25
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Koeleman BPC, de Kovel CGF, Kasteleijn-Nolst Trenité DGA. Photoparoxysmal EEG response and genetic dissection of juvenile myoclonic epilepsy. Epilepsy Behav 2013; 28 Suppl 1:S69-71. [PMID: 23756485 DOI: 10.1016/j.yebeh.2012.07.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Accepted: 07/04/2012] [Indexed: 11/25/2022]
Abstract
Heritable EEG traits are often associated with epilepsy, and photoparoxysmal EEG response (PPR) is the most notable example of this observation in JME. Such EEG traits may be a subclinical expression of the defective mechanism that leads to epilepsy. Therefore, these traits can be used to map epilepsy genes by dissecting the complex epilepsy phenotype in endophenotypic sections that on their own have a presumed monogenic cause. Two characteristics make PPR particularly interesting as a useful endophenotype for epilepsy gene mapping. First, it shows an increased comorbidity with some but not all forms of epilepsy. Second, its mode of inheritance is compatible with a monogenic cause, which promises relative straightforward gene identification through positional cloning. Here, we summarize the current state of affairs.
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Affiliation(s)
- Bobby P C Koeleman
- Department of Medical Genetics, University Medical Center Utrecht, The Netherlands.
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26
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Abstract
Occipital lobe epilepsies (OLEs) manifest with occipital seizures from an epileptic focus within the occipital lobes. Ictal clinical symptoms are mainly visual and oculomotor. Elementary visual hallucinations are common and characteristic. Postictal headache occurs in more than half of patients (epilepsy-migraine sequence). Electroencephalography (EEG) is of significant diagnostic value, but certain limitations should be recognized. Occipital spikes and/or occipital paroxysms either spontaneous or photically induced are the main interictal EEG abnormalities in idiopathic OLE. However, occipital epileptiform abnormalities may also occur without clinical relationship to seizures particularly in children. In cryptogenic/symptomatic OLE, unilateral posterior EEG slowing is more common than occipital spikes. In neurosurgical series of symptomatic OLE, interictal EEG abnormalities are rarely strictly occipital. The most common localization is in the posterior temporal regions and less than one-fifth show occipital spikes. In photosensitive OLE, intermittent photic stimulation elicits (1) spikes/polyspikes confined in the occipital regions or (2) generalized spikes/polyspikes with posterior emphasis. In ictal EEG, a well-localized unifocal rhythmic ictal discharge during occipital seizures is infrequent. A bioccipital field spread to the temporal regions is common. Frequency, severity, and response to treatment vary considerably from good to intractable and progressive mainly depending on underlying causes.
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27
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Smith AK, Conneely KN, Newport DJ, Kilaru V, Schroeder JW, Pennell PB, Knight BT, Cubells JC, Stowe ZN, Brennan PA. Prenatal antiepileptic exposure associates with neonatal DNA methylation differences. Epigenetics 2012; 7:458-63. [PMID: 22419127 DOI: 10.4161/epi.19617] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Antiepileptic drugs (AEDs) are used to treat a variety of neuropsychiatric illnesses commonly encountered in women during their reproductive years, including epilepsy and bipolar disorder. Despite their widespread use, the impact of prenatal exposure on fetal development remains obscure. To evaluate whether AEDs taken by pregnant mothers influence DNA methylation patterns in their neonates, DNA was extracted from the umbilical cord blood of 201 neonates whose mothers were treated for neuropsychiatric illness during pregnancy and interrogated across 27,578 CpG sites using the Illumina HumanMethylation27 BeadChip. The association of each methylation value with the cumulative duration of prenatal AED exposure was examined using a linear mixed model. The average methylation level across all CpG sites was calculated for each subject, and this global methylation measure was evaluated similarly. Neonates with a longer duration of AED exposure in pregnancy showed a decrease in average global methylation (p = 0.0045). Further, DNA methylation of CpG sites in 14 genes significantly decreased with the duration of prenatal AED exposure even after adjusting for multiple comparisons (FDR < 0.05). For a small subset (n = 19) of these neonates, a second tissue, placenta, was available in addition to cord blood. Methylation of 3 of these 14 CpG sites was also significantly decreased in placental tissue. These novel data suggest decreased DNA methylation in neonates of mothers who took AEDs during pregnancy. The long-term stability and potential impact of these changes warrant further attention, and caution may be warranted before prescribing AEDs to pregnant women.
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Affiliation(s)
- Alicia K Smith
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA.
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28
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Strigaro G, Prandi P, Varrasi C, Monaco F, Cantello R. Defective visual inhibition in photosensitive idiopathic generalized epilepsy. Epilepsia 2012; 53:695-704. [DOI: 10.1111/j.1528-1167.2012.03411.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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29
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Genetic linkage analysis of a large family with photoparoxysmal response. Epilepsy Res 2011; 99:38-45. [PMID: 22071551 DOI: 10.1016/j.eplepsyres.2011.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 09/18/2011] [Accepted: 10/09/2011] [Indexed: 11/23/2022]
Abstract
In this study, we report the results of a genetic linkage analysis of a large family with photoparoxysmal response, defined by the presence of a photoparoxysmal response (PPR) on EEG. The participants were genotyped using an 8 cM whole genome wide scan, and both parametric and non-parametric linkage analysis were carried out. The parametric analysis by MLINK did not identify any definite conclusion but a region of interest on chromosome 1 near marker D1S2865; and non-parametric linkage analysis found a locus of interest on chromosome 16, near marker D16S2621. The possible confounding factors for, and pathogenic implication of, and the results are discussed.
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30
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von Spiczak S, Finsterwalder K, Muhle H, Franke A, Schilhabel M, Stephani U, Helbig I. Comprehensive analysis of candidate genes for photosensitivity using a complementary bioinformatic and experimental approach. Epilepsia 2011; 52:e143-7. [PMID: 21883175 DOI: 10.1111/j.1528-1167.2011.03197.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Photoparoxysmal response (PPR) is a highly heritable electroencephalographic trait characterized by an increased sensitivity to photic stimulation. It may serve as an endophenotype for idiopathic generalized epilepsy. Family linkage studies identified susceptibility loci for PPR on chromosomes 5q35.3, 8q21.13, and 16p13.3. This study aimed to identify key candidate genes within these loci. We used bioinformatics tools for gene prioritization integrating information on biologic function, sequence data, gene expression, and others. The prime candidate gene from this analysis was sequenced in 48 photopositive probands. Presumed functional implications of identified polymorphisms were investigated using bioinformatics methods. The glutamate receptor subunit gene GRIN2A was identified as a prime candidate gene. Sequence analysis revealed various new polymorphisms. None of the identified variants was predicted to be functionally relevant. We objectified the selection of candidate genes for PPR without an a priori hypothesis. Particularly among the various ion channel genes in the linkage regions, GRIN2A was identified as the prime candidate gene. GRIN2A mutations have recently been identified in various epilepsies. Even though our mutation analysis failed to demonstrate direct involvement of GRIN2A in photosensitivity, in silico gene prioritization may provide a useful tool for the identification of candidate genes within large genomic regions.
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Affiliation(s)
- Sarah von Spiczak
- Department of Neuropediatrics, Christian-Albrechts-University Kiel and University Medical Center Schleswig-Holstein, Campus Kiel, Kiel, Germany.
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31
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Velíšek L, Shang E, Velíšková J, Chachua T, Macchiarulo S, Maglakelidze G, Wolgemuth DJ, Greenberg DA. GABAergic neuron deficit as an idiopathic generalized epilepsy mechanism: the role of BRD2 haploinsufficiency in juvenile myoclonic epilepsy. PLoS One 2011; 6:e23656. [PMID: 21887291 PMCID: PMC3161054 DOI: 10.1371/journal.pone.0023656] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Accepted: 07/22/2011] [Indexed: 11/23/2022] Open
Abstract
Idiopathic generalized epilepsy (IGE) syndromes represent about 30% of all epilepsies. They have strong, but elusive, genetic components and sex-specific seizure expression. Multiple linkage and population association studies have connected the bromodomain-containing gene BRD2 to forms of IGE. In mice, a null mutation at the homologous Brd2 locus results in embryonic lethality while heterozygous Brd2+/− mice are viable and overtly normal. However, using the flurothyl model, we now show, that compared to the Brd2+/+ littermates, Brd2+/− males have a decreased clonic, and females a decreased tonic-clonic, seizure threshold. Additionally, long-term EEG/video recordings captured spontaneous seizures in three out of five recorded Brd2+/− female mice. Anatomical analysis of specific regions of the brain further revealed significant differences in Brd2+/− vs +/+ mice. Specifically, there were decreases in the numbers of GABAergic (parvalbumin- or GAD67-immunopositive) neurons along the basal ganglia pathway, i.e., in the neocortex and striatum of Brd2+/− mice, compared to Brd2+/+ mice. There were also fewer GABAergic neurons in the substantia nigra reticulata (SNR), yet there was a minor, possibly compensatory increase in the GABA producing enzyme GAD67 in these SNR cells. Further, GAD67 expression in the superior colliculus and ventral medial thalamic nucleus, the main SNR outputs, was significantly decreased in Brd2+/− mice, further supporting GABA downregulation. Our data show that the non-channel-encoding, developmentally critical Brd2 gene is associated with i) sex-specific increases in seizure susceptibility, ii) the development of spontaneous seizures, and iii) seizure-related anatomical changes in the GABA system, supporting BRD2's involvement in human IGE.
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Affiliation(s)
- Libor Velíšek
- Department of Cell Biology & Anatomy, New York College of Medicine, Valhalla, New York, United States of America.
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