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Thom M. Review: Hippocampal sclerosis in epilepsy: a neuropathology review. Neuropathol Appl Neurobiol 2015; 40:520-43. [PMID: 24762203 PMCID: PMC4265206 DOI: 10.1111/nan.12150] [Citation(s) in RCA: 328] [Impact Index Per Article: 36.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 04/23/2014] [Indexed: 12/12/2022]
Abstract
Hippocampal sclerosis (HS) is a common pathology encountered in mesial temporal lobe epilepsy (MTLE) as well as other epilepsy syndromes and in both surgical and post-mortem practice. The 2013 International League Against Epilepsy (ILAE) classification segregates HS into typical (type 1) and atypical (type 2 and 3) groups, based on the histological patterns of subfield neuronal loss and gliosis. In addition, granule cell reorganization and alterations of interneuronal populations, neuropeptide fibre networks and mossy fibre sprouting are distinctive features of HS associated with epilepsies; they can be useful diagnostic aids to discriminate from other causes of HS, as well as highlighting potential mechanisms of hippocampal epileptogenesis. The cause of HS remains elusive and may be multifactorial; the contribution of febrile seizures, genetic susceptibility, inflammatory and neurodevelopmental factors are discussed. Post-mortem based research in HS, as an addition to studies on surgical samples, has the added advantage of enabling the study of the wider network changes associated with HS, the long-term effects of epilepsy on the pathology and associated comorbidities. It is likely that HS is heterogeneous in aspects of its cause, epileptogenetic mechanisms, network alterations and response to medical and surgical treatments. Future neuropathological studies will contribute to better recognition and understanding of these clinical and patho-aetiological subtypes of HS.
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Affiliation(s)
- Maria Thom
- Departments of Neuropathology and Clinical and Experimental Epilepsy, Institute of Neurology, University College London, London, UK
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Jacobsen KK, Nievergelt CM, Zayats T, Greenwood TA, Anttila V, Akiskal HS, Haavik J, Fasmer OB, Kelsoe JR, Johansson S, Oedegaard KJ. Genome wide association study identifies variants in NBEA associated with migraine in bipolar disorder. J Affect Disord 2015; 172:453-61. [PMID: 25451450 PMCID: PMC4394021 DOI: 10.1016/j.jad.2014.10.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 01/19/2023]
Abstract
BACKGROUND Migraine is a common comorbidity among individuals with bipolar disorder, but the underlying mechanisms for this co-occurrence are poorly understood. The aim of this study was to investigate the genetic background of bipolar patients with and without migraine. METHODS We performed a genome-wide association analysis contrasting 460 bipolar migraneurs with 914 bipolar patients without migraine from the Bipolar Genome Study (BiGS). RESULTS We identified one genome-wide significant association between migraine in bipolar disorder patients and rs1160720, an intronic single nucleotide polymorphism (SNP) in the NBEA gene (P=2.97 × 10(-8), OR: 1.82, 95% CI: 1.47-2.25), although this was not replicated in a smaller sample of 289 migraine cases. LIMITATIONS Our study is based on self-reported migraine. CONCLUSIONS NBEA encodes neurobeachin, a scaffolding protein primarily expressed in the brain and involved in trafficking of vesicles containing neurotransmitter receptors. This locus has not previously been implicated in migraine per se. We found no evidence of association in data from the GWAS migraine meta-analysis consortium (n=118,710 participants) suggesting that the association might be specific to migraine co-morbid with bipolar disorder.
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Affiliation(s)
- Kaya K. Jacobsen
- Department of Biomedicine, University of Bergen, Norway,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway,K. G. Jebsen Center for Research on Neuropsychiatric Disorders, University of Bergen, Norway
| | | | - Tetyana Zayats
- Department of Biomedicine, University of Bergen, Norway,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway,K. G. Jebsen Center for Research on Neuropsychiatric Disorders, University of Bergen, Norway
| | | | - Verneri Anttila
- Analytical and Translational Genetics Unit, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA,lnstitute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | | | - Hagop S. Akiskal
- Department of Psychiatry, University of California San Diego, USA,Department of Psychiatry, VA Hospital, San Diego, USA
| | | | - Jan Haavik
- Department of Biomedicine, University of Bergen, Norway,K. G. Jebsen Center for Research on Neuropsychiatric Disorders, University of Bergen, Norway,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway
| | - Ole Bernt Fasmer
- K. G. Jebsen Center for Research on Neuropsychiatric Disorders, University of Bergen, Norway,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway,Department of Clinical Medicine, Section for Psychiatry, Faculty of Medicine and Dentistry, University of Bergen, Norway
| | - John R. Kelsoe
- Department of Psychiatry, University of California San Diego, USA,Department of Psychiatry, VA Hospital, San Diego, USA
| | - Stefan Johansson
- Department of Biomedicine, University of Bergen, Norway,Center for Medical Genetics and Molecular Medicine, Haukeland University Hospital, Bergen, Norway,K. G. Jebsen Center for Research on Neuropsychiatric Disorders, University of Bergen, Norway,Department of Clinical Science, University of Bergen, Norway
| | - Ketil J. Oedegaard
- K. G. Jebsen Center for Research on Neuropsychiatric Disorders, University of Bergen, Norway,Division of Psychiatry, Haukeland University Hospital, Bergen, Norway,Department of Clinical Medicine, Section for Psychiatry, Faculty of Medicine and Dentistry, University of Bergen, Norway
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Johnson MR, Behmoaras J, Bottolo L, Krishnan ML, Pernhorst K, Santoscoy PLM, Rossetti T, Speed D, Srivastava PK, Chadeau-Hyam M, Hajji N, Dabrowska A, Rotival M, Razzaghi B, Kovac S, Wanisch K, Grillo FW, Slaviero A, Langley SR, Shkura K, Roncon P, De T, Mattheisen M, Niehusmann P, O'Brien TJ, Petrovski S, von Lehe M, Hoffmann P, Eriksson J, Coffey AJ, Cichon S, Walker M, Simonato M, Danis B, Mazzuferi M, Foerch P, Schoch S, De Paola V, Kaminski RM, Cunliffe VT, Becker AJ, Petretto E. Systems genetics identifies Sestrin 3 as a regulator of a proconvulsant gene network in human epileptic hippocampus. Nat Commun 2015; 6:6031. [PMID: 25615886 DOI: 10.1038/ncomms7031] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 12/04/2014] [Indexed: 01/20/2023] Open
Abstract
Gene-regulatory network analysis is a powerful approach to elucidate the molecular processes and pathways underlying complex disease. Here we employ systems genetics approaches to characterize the genetic regulation of pathophysiological pathways in human temporal lobe epilepsy (TLE). Using surgically acquired hippocampi from 129 TLE patients, we identify a gene-regulatory network genetically associated with epilepsy that contains a specialized, highly expressed transcriptional module encoding proconvulsive cytokines and Toll-like receptor signalling genes. RNA sequencing analysis in a mouse model of TLE using 100 epileptic and 100 control hippocampi shows the proconvulsive module is preserved across-species, specific to the epileptic hippocampus and upregulated in chronic epilepsy. In the TLE patients, we map the trans-acting genetic control of this proconvulsive module to Sestrin 3 (SESN3), and demonstrate that SESN3 positively regulates the module in macrophages, microglia and neurons. Morpholino-mediated Sesn3 knockdown in zebrafish confirms the regulation of the transcriptional module, and attenuates chemically induced behavioural seizures in vivo.
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Affiliation(s)
- Michael R Johnson
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, London W12 0NN, UK
| | - Jacques Behmoaras
- Centre for Complement and Inflammation Research, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Leonardo Bottolo
- Department of Mathematics, Imperial College London, 180 Queen's Gate, London SW7 2AZ, UK
| | - Michelle L Krishnan
- Centre for the Developing Brain, Department of Perinatal Imaging and Health, St Thomas' Hospital, King's College London, London SE1 7EH, UK
| | - Katharina Pernhorst
- Section of Translational Epileptology, Department of Neuropathology, University of Bonn, Sigmund Freud Street 25, Bonn D-53127, Germany
| | - Paola L Meza Santoscoy
- Department of Biomedical Science, Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Tiziana Rossetti
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Doug Speed
- UCL Genetics Institute, University College London, Gower Street, London WC1E 6BT, UK
| | - Prashant K Srivastava
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, London W12 0NN, UK.,Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Marc Chadeau-Hyam
- Department of Epidemiology and Biostatistics, School of Public Health, MRC/PHE Centre for Environment and Health, Imperial College London, St Mary's Hospital, Norfolk Place, W21PG London, UK
| | - Nabil Hajji
- Department of Medicine, Centre for Pharmacology and Therapeutics, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Aleksandra Dabrowska
- Department of Medicine, Centre for Pharmacology and Therapeutics, Imperial College London, Du Cane Road, London W12 0NN, UK
| | - Maxime Rotival
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Banafsheh Razzaghi
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Stjepana Kovac
- Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Klaus Wanisch
- Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Federico W Grillo
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Anna Slaviero
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Sarah R Langley
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, London W12 0NN, UK.,Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Kirill Shkura
- Division of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, Burlington Danes Building, London W12 0NN, UK.,Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Paolo Roncon
- Department of Medical Sciences, Section of Pharmacology and Neuroscience Center, University of Ferrara, 44121 Ferrara, Italy.,National Institute of Neuroscience, 44121 Ferrara, Italy
| | - Tisham De
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Manuel Mattheisen
- Department of Genomics, Life and Brain Center, University of Bonn, D-53127 Bonn, Germany.,Institute of Human Genetics, University of Bonn, D-53127 Bonn, Germany.,Institute for Genomic Mathematics, University of Bonn, D-53127 Bonn, Germany
| | - Pitt Niehusmann
- Section of Translational Epileptology, Department of Neuropathology, University of Bonn, Sigmund Freud Street 25, Bonn D-53127, Germany
| | - Terence J O'Brien
- Department of Medicine, RMH, University of Melbourne, Royal Melbourne Hospital, Royal Parade, Parkville, Victoria 3050, Australia
| | - Slave Petrovski
- Department of Neurology, Royal Melbourne Hospital, Melbourne, Parkville, Victoria 3050, Australia
| | - Marec von Lehe
- Department of Neurosurgery, University of Bonn Medical Center, Sigmund-Freud-Strasse 25, 53105 Bonn, Germany
| | - Per Hoffmann
- Institute of Human Genetics, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany.,Department of Biomedicine, University of Basel, Hebelstrasse 20, 4056 Basel, Switzerland
| | - Johan Eriksson
- Folkhälsan Research Centre, Topeliusgatan 20, 00250 Helsinki, Finland.,Helsinki University Central Hospital, Unit of General Practice, Haartmaninkatu 4, Helsinki 00290, Finland.,Department of General Practice and Primary Health Care, University of Helsinki, 407, PO Box 20, Tukholmankatu 8 B, Helsinki 00014, Finland
| | - Alison J Coffey
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton CB10 1SA, UK
| | - Sven Cichon
- Institute of Human Genetics, University of Bonn, Sigmund-Freud-Strasse 25, 53127 Bonn, Germany.,Department of Biomedicine, University of Basel, Hebelstrasse 20, 4056 Basel, Switzerland
| | - Matthew Walker
- Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Michele Simonato
- Department of Medical Sciences, Section of Pharmacology and Neuroscience Center, University of Ferrara, 44121 Ferrara, Italy.,National Institute of Neuroscience, 44121 Ferrara, Italy.,Laboratory for Technologies of Advanced Therapies (LTTA), University of Ferrara, 44121 Ferrara, Italy
| | - Bénédicte Danis
- Neuroscience TA, UCB Biopharma SPRL, Avenue de l'industrie, R9, B-1420 Braine l'Alleud, Belgium
| | - Manuela Mazzuferi
- Neuroscience TA, UCB Biopharma SPRL, Avenue de l'industrie, R9, B-1420 Braine l'Alleud, Belgium
| | - Patrik Foerch
- Neuroscience TA, UCB Biopharma SPRL, Avenue de l'industrie, R9, B-1420 Braine l'Alleud, Belgium
| | - Susanne Schoch
- Section of Translational Epileptology, Department of Neuropathology, University of Bonn, Sigmund Freud Street 25, Bonn D-53127, Germany.,Department of Epileptology, University of Bonn Medical Center, Sigmund-Freud-Strasse 25, Bonn D-53127, Germany
| | - Vincenzo De Paola
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK
| | - Rafal M Kaminski
- Neuroscience TA, UCB Biopharma SPRL, Avenue de l'industrie, R9, B-1420 Braine l'Alleud, Belgium
| | - Vincent T Cunliffe
- Department of Biomedical Science, Bateson Centre, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, UK
| | - Albert J Becker
- Section of Translational Epileptology, Department of Neuropathology, University of Bonn, Sigmund Freud Street 25, Bonn D-53127, Germany
| | - Enrico Petretto
- Medical Research Council (MRC) Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, Du Cane Road, London W12 0NN, UK.,Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore
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Abstract
This review considers pharmacogenetics of the so called 'second-generation' antipsychotics. Findings for polymorphisms replicating in more than one study are emphasized and compared and contrasted with larger-scale candidate gene studies and genome-wide association study analyses. Variants in three types of genes are discussed: pharmacokinetic genes associated with drug metabolism and disposition, pharmacodynamic genes encoding drug targets, and pharmacotypic genes impacting disease presentation and subtype. Among pharmacokinetic markers, CYP2D6 metabolizer phenotype has clear clinical significance, as it impacts dosing considerations for aripiprazole, iloperidone and risperidone, and variants of the ABCB1 gene hold promise as biomarkers for dosing for olanzapine and clozapine. Among pharmacodynamic variants, the TaqIA1 allele of the DRD2 gene, the DRD3 (Ser9Gly) polymorphism, and the HTR2C -759C/T polymorphism have emerged as potential biomarkers for response and/or side effects. However, large-scale candidate gene studies and genome-wide association studies indicate that pharmacotypic genes may ultimately prove to be the richest source of biomarkers for response and side effect profiles for second-generation antipsychotics.
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Affiliation(s)
- Mark D Brennan
- Department of Biochemistry & Molecular Biology, School of Medicine, University of Louisville, Louisville, KY 40292, USA.
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Tan MS, Jiang T, Tan L, Yu JT. Genome-wide association studies in neurology. ANNALS OF TRANSLATIONAL MEDICINE 2015; 2:124. [PMID: 25568877 DOI: 10.3978/j.issn.2305-5839.2014.11.12] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/20/2013] [Accepted: 03/04/2013] [Indexed: 12/11/2022]
Abstract
Genome-wide association studies (GWAS) are a powerful tool for understanding the genetic underpinnings of human disease. In this article, we briefly review the role and findings of GWAS in common neurological diseases, including Stroke, Alzheimer's disease, Parkinson's disease, epilepsy, multiple sclerosis, migraine, amyotrophic lateral sclerosis, frontotemporal lobar degeneration, restless legs syndrome, intracranial aneurysm, human prion diseases and moyamoya disease. We then discuss the present and future implications of these findings with regards to disease prediction, uncovering basic biology, and the development of potential therapeutic agents.
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Affiliation(s)
- Meng-Shan Tan
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
| | - Teng Jiang
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
| | - Lan Tan
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
| | - Jin-Tai Yu
- 1 College of Medicine and Pharmaceutics, Ocean University of China, Qingdao 266071, China ; 2 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Qingdao 266071, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266071, China
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Seven M, Batar B, Unal S, Yesil G, Yuksel A, Guven M. The effect of genetic polymorphisms of cytochrome P450 CYP2C9, CYP2C19, and CYP2D6 on drug-resistant epilepsy in Turkish children. Mol Diagn Ther 2014; 18:229-36. [PMID: 24338437 DOI: 10.1007/s40291-013-0078-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND AND OBJECTIVE Despite the availability of several antiepileptic drugs, drug resistance remains one of the major challenges in epilepsy therapy. Genetic factors are known to play a significant role in the prognosis and treatment of epilepsy. The aim of this study was to determine the frequencies of alleles for CYP2C9, CYP2C19, and CYP2D6 genes in Turkish children with epilepsy, and to investigate the relationship between the genetic polymorphism of these genes with multiple drug resistance in epilepsy patients. METHODS We genotyped 132 epileptic patients (60 drug resistant and 72 drug responsive) and 55 healthy controls for six single nucleotide polymorphisms (SNPs) in CYP2C9, CYP2C19, and CYP2D6. Genotype, allele, and haplotype frequencies were compared between groups. RESULTS The frequencies of CYP2C9*3/*3 genotype and CYP2C9*3 allele, and the haplotype CCGG (CYP2C9*2 C>T, CYP2C9*3 A>C, and CYP2C19*2 G>A, CYP2C19* G>A) were significantly higher in drug-resistant versus -responsive patients. CONCLUSION Our results demonstrated the important role of the CYP2C9*3 allelic variant in preventing epilepsy patients from developing drug resistance. These data suggest that CYP2C9, CYP2C19, and CYP2D6 SNPs and haplotypes may affect the response to antiepileptic drugs.
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Affiliation(s)
- Mehmet Seven
- Department of Medical Genetics, Cerrahpasa Medical Faculty, Istanbul University, Istanbul, Turkey
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57
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Abstract
Background The epilepsies are a clinically heterogeneous group of neurological disorders. Despite strong evidence for heritability, genome-wide association studies have had little success in identification of risk loci associated with epilepsy, probably because of relatively small sample sizes and insufficient power. We aimed to identify risk loci through meta-analyses of genome-wide association studies for all epilepsy and the two largest clinical subtypes (genetic generalised epilepsy and focal epilepsy). Methods We combined genome-wide association data from 12 cohorts of individuals with epilepsy and controls from population-based datasets. Controls were ethnically matched with cases. We phenotyped individuals with epilepsy into categories of genetic generalised epilepsy, focal epilepsy, or unclassified epilepsy. After standardised filtering for quality control and imputation to account for different genotyping platforms across sites, investigators at each site conducted a linear mixed-model association analysis for each dataset. Combining summary statistics, we conducted fixed-effects meta-analyses of all epilepsy, focal epilepsy, and genetic generalised epilepsy. We set the genome-wide significance threshold at p<1·66 × 10−8. Findings We included 8696 cases and 26 157 controls in our analysis. Meta-analysis of the all-epilepsy cohort identified loci at 2q24.3 (p=8·71 × 10−10), implicating SCN1A, and at 4p15.1 (p=5·44 × 10−9), harbouring PCDH7, which encodes a protocadherin molecule not previously implicated in epilepsy. For the cohort of genetic generalised epilepsy, we noted a single signal at 2p16.1 (p=9·99 × 10−9), implicating VRK2 or FANCL. No single nucleotide polymorphism achieved genome-wide significance for focal epilepsy. Interpretation This meta-analysis describes a new locus not previously implicated in epilepsy and provides further evidence about the genetic architecture of these disorders, with the ultimate aim of assisting in disease classification and prognosis. The data suggest that specific loci can act pleiotropically raising risk for epilepsy broadly, or can have effects limited to a specific epilepsy subtype. Future genetic analyses might benefit from both lumping (ie, grouping of epilepsy types together) or splitting (ie, analysis of specific clinical subtypes). Funding International League Against Epilepsy and multiple governmental and philanthropic agencies.
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Speed D, O'Brien TJ, Palotie A, Shkura K, Marson AG, Balding DJ, Johnson MR. Describing the genetic architecture of epilepsy through heritability analysis. ACTA ACUST UNITED AC 2014; 137:2680-9. [PMID: 25063994 PMCID: PMC4163034 DOI: 10.1093/brain/awu206] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Epilepsy is highly heritable, but its genetic architecture is poorly understood. Speed et al. estimate the number of susceptibility loci, show that common variants account for the majority of heritability, and demonstrate that epilepsy consists of genetically distinct subtypes. They conclude that gene-based prediction models may have clinical utility in first-seizure settings. Epilepsy is a disease with substantial missing heritability; despite its high genetic component, genetic association studies have had limited success detecting common variants which influence susceptibility. In this paper, we reassess the role of common variants on epilepsy using extensions of heritability analysis. Our data set consists of 1258 UK patients with epilepsy, of which 958 have focal epilepsy, and 5129 population control subjects, with genotypes recorded for over 4 million common single nucleotide polymorphisms. Firstly, we show that on the liability scale, common variants collectively explain at least 26% (standard deviation 5%) of phenotypic variation for all epilepsy and 27% (standard deviation 5%) for focal epilepsy. Secondly we provide a new method for estimating the number of causal variants for complex traits; when applied to epilepsy, our most optimistic estimate suggests that at least 400 variants influence disease susceptibility, with potentially many thousands. Thirdly, we use bivariate analysis to assess how similar the genetic architecture of focal epilepsy is to that of non-focal epilepsy; we demonstrate both significant differences (P = 0.004) and significant similarities (P = 0.01) between the two subtypes, indicating that although the clinical definition of focal epilepsy does identify a genetically distinct epilepsy subtype, there is also scope to improve the classification of epilepsy by incorporating genotypic information. Lastly, we investigate the potential value in using genetic data to diagnose epilepsy following a single epileptic seizure; we find that a prediction model explaining 10% of phenotypic variation could have clinical utility for deciding which single-seizure individuals are likely to benefit from immediate anti-epileptic drug therapy.
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Affiliation(s)
- Doug Speed
- 1 UCL Genetics Institute, University College London, London WC1E 6BT, UK
| | - Terence J O'Brien
- 2 The Departments of Medicine and Neurology, The Royal Melbourne Hospital, The University of Melbourne, Australia
| | - Aarno Palotie
- 3 Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Finland 4 The Broad Institute of MIT and Harvard, Cambridge, USA 5 Department of Medical Genetics, University of Helsinki, Finland 6 University Central Hospital, Helsinki, Finland
| | - Kirill Shkura
- 7 Division of Brain Sciences, Imperial College London, London W6 8RF, UK 8 Medical Research Council (MRC) Clinical Sciences Centre, Faculty of Medicine, Imperial College London, UK
| | - Anthony G Marson
- 9 Department of Molecular and Clinical Pharmacology, University of Liverpool, UK
| | - David J Balding
- 1 UCL Genetics Institute, University College London, London WC1E 6BT, UK
| | - Michael R Johnson
- 7 Division of Brain Sciences, Imperial College London, London W6 8RF, UK
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Multivariate analysis reveals genetic associations of the resting default mode network in psychotic bipolar disorder and schizophrenia. Proc Natl Acad Sci U S A 2014; 111:E2066-75. [PMID: 24778245 DOI: 10.1073/pnas.1313093111] [Citation(s) in RCA: 172] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The brain's default mode network (DMN) is highly heritable and is compromised in a variety of psychiatric disorders. However, genetic control over the DMN in schizophrenia (SZ) and psychotic bipolar disorder (PBP) is largely unknown. Study subjects (n = 1,305) underwent a resting-state functional MRI scan and were analyzed by a two-stage approach. The initial analysis used independent component analysis (ICA) in 324 healthy controls, 296 SZ probands, 300 PBP probands, 179 unaffected first-degree relatives of SZ probands (SZREL), and 206 unaffected first-degree relatives of PBP probands to identify DMNs and to test their biomarker and/or endophenotype status. A subset of controls and probands (n = 549) then was subjected to a parallel ICA (para-ICA) to identify imaging-genetic relationships. ICA identified three DMNs. Hypo-connectivity was observed in both patient groups in all DMNs. Similar patterns observed in SZREL were restricted to only one network. DMN connectivity also correlated with several symptom measures. Para-ICA identified five sub-DMNs that were significantly associated with five different genetic networks. Several top-ranking SNPs across these networks belonged to previously identified, well-known psychosis/mood disorder genes. Global enrichment analyses revealed processes including NMDA-related long-term potentiation, PKA, immune response signaling, axon guidance, and synaptogenesis that significantly influenced DMN modulation in psychoses. In summary, we observed both unique and shared impairments in functional connectivity across the SZ and PBP cohorts; these impairments were selectively familial only for SZREL. Genes regulating specific neurodevelopment/transmission processes primarily mediated DMN disconnectivity. The study thus identifies biological pathways related to a widely researched quantitative trait that might suggest novel, targeted drug treatments for these diseases.
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61
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Ferraro TN. The relationship between genes affecting the development of epilepsy and approaches to epilepsy therapy. Expert Rev Neurother 2014; 14:329-52. [DOI: 10.1586/14737175.2014.888651] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Boycott KM, Dyment DA, Sawyer SL, Vanstone MR, Beaulieu CL. Identification of Genes for Childhood Heritable Diseases. Annu Rev Med 2014; 65:19-31. [DOI: 10.1146/annurev-med-101712-122108] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Kym M. Boycott
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, K1H 8L1 Canada; , , , , ,
| | - David A. Dyment
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, K1H 8L1 Canada; , , , , ,
| | - Sarah L. Sawyer
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, K1H 8L1 Canada; , , , , ,
| | - Megan R. Vanstone
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, K1H 8L1 Canada; , , , , ,
| | - Chandree L. Beaulieu
- Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, Ontario, K1H 8L1 Canada; , , , , ,
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Qu J, Zhang Y, Yang ZQ, Mao XY, Zhou BT, Yin JY, He H, Li XP, Long HY, Lv N, Xu XJ, Xiao B, Zhang Y, Tang Q, Hu DL, Zhou HH, Liu ZQ. Gene-wide tagging study of the association between KCNT1 polymorphisms and the susceptibility and efficacy of genetic generalized epilepsy in Chinese population. CNS Neurosci Ther 2013; 20:140-6. [PMID: 24279416 DOI: 10.1111/cns.12169] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/06/2013] [Accepted: 08/07/2013] [Indexed: 11/29/2022] Open
Abstract
AIMS The causes of genetic generalized epilepsies (GGEs) are still uncertain now. Some studies found that the human potassium channel, subfamily T, member 1 (KCNT1) is the candidate gene causing malignant migrating partial seizures of infancy and autosomal dominant nocturnal frontal lobe epilepsy which are all rare genetic generalized epilepsies. The aims of this study were going to evaluate the association between KCNT1 common variations and the susceptibility and drug resistance of genetic generalized epilepsies in Chinese population. METHODS The allele-specific MALDI-TOF mass spectrometry method was used to assess 17 tagSNPs (tagged single-nucleotide polymorphisms) of KCNT1 in 284 healthy Chinese controls and 483 Chinese GGEs patients including 279 anti-epileptic drug-responsive patients and 204 drug-resistant patients. RESULTS Genotype distributions of all the selected tagSNPs were consistent with Hardy-Weinberg equilibrium in GGEs and healthy controls. None of the all 17 tagSNPs alleles were found to be related with the susceptibility and drug resistance of genetic generalized epilepsies. The frequencies of haplotype 5 and haplotype 1 were significantly lower in GGEs than that in healthy controls (2% vs. 4%, OR = 0.47 [0.27-0.94], P = 0.03) and obviously higher in drug-resistant patients than that in drug-response patients (6% vs. 3%, OR = 2.56 [1.23-5.35], P = 0.01). However, after the correction of multiple comparisons with Bonferroni's method, we found that the above two haplotypes were not associated with the susceptibility and drug resistance in GGEs and healthy controls. CONCLUSION This gene-wide tagging study revealed no association between KCNT1 17 common variations and susceptibility of GGEs or AEDs (anti-epileptic drugs) efficacy of genetic generalized epilepsies in Chinese population.
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Affiliation(s)
- Jian Qu
- Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University Xiangya School of Medicine, Changsha, China
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Zhang S, Kwan P, Baum L. The potential role of CAMSAP1L1 in symptomatic epilepsy. Neurosci Lett 2013; 556:146-51. [PMID: 24148305 DOI: 10.1016/j.neulet.2013.10.020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 10/02/2013] [Accepted: 10/10/2013] [Indexed: 11/18/2022]
Abstract
In a recent genome-wide association study (GWAS) of symptomatic epilepsy in the Chinese population, the most significant single nucleotide polymorphism (SNP) allele was rs2292096 [G] (P=1.0×10(-8), odds ratio [OR]=0.63), in the CAMSAP1L1 gene (also known as CAMSAP2). Here, we report that rs2292096 genotypes tended to associate with expression of CAMSAP1L1 RNA in the temporal lobe (p=0.054) and hippocampus (p=0.20) of epilepsy surgery patients, with expression tending to increase with the G allele. CAMSAP1L1 and β-tubulin double immunofluorescence exhibited partial overlap. CAMSAP1L1 siRNA transfection of human SH-SY5Y neuroblastoma cells treated with or without retinoic acid reduced the CAMSAP1L1 protein level nearly 60% and stimulated neurite outgrowth, as measured by total length, number of processes and number of branches. Therefore, the rs2292096 G allele of CAMSAP1L1, which was associated with reduced risk of symptomatic epilepsy, tended to associate with increased expression of CAMSAP1L1, which represses neurite outgrowth. Greater neurite growth in response to brain insults might increase formation of ectopic neural circuits and thus the risk of epileptogenesis.
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Affiliation(s)
- Shuai Zhang
- School of Pharmacy, The Chinese University of Hong Kong, Shatin, Hong Kong, China
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65
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Kasperavičiūtė D, Catarino CB, Matarin M, Leu C, Novy J, Tostevin A, Leal B, Hessel EVS, Hallmann K, Hildebrand MS, Dahl HHM, Ryten M, Trabzuni D, Ramasamy A, Alhusaini S, Doherty CP, Dorn T, Hansen J, Krämer G, Steinhoff BJ, Zumsteg D, Duncan S, Kälviäinen RK, Eriksson KJ, Kantanen AM, Pandolfo M, Gruber-Sedlmayr U, Schlachter K, Reinthaler EM, Stogmann E, Zimprich F, Théâtre E, Smith C, O’Brien TJ, Meng Tan K, Petrovski S, Robbiano A, Paravidino R, Zara F, Striano P, Sperling MR, Buono RJ, Hakonarson H, Chaves J, Costa PP, Silva BM, da Silva AM, de Graan PNE, Koeleman BPC, Becker A, Schoch S, von Lehe M, Reif PS, Rosenow F, Becker F, Weber Y, Lerche H, Rössler K, Buchfelder M, Hamer HM, Kobow K, Coras R, Blumcke I, Scheffer IE, Berkovic SF, Weale ME, Delanty N, Depondt C, Cavalleri GL, Kunz WS, Sisodiya SM. Epilepsy, hippocampal sclerosis and febrile seizures linked by common genetic variation around SCN1A. Brain 2013; 136:3140-50. [PMID: 24014518 PMCID: PMC3784283 DOI: 10.1093/brain/awt233] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Revised: 06/28/2013] [Accepted: 07/02/2013] [Indexed: 01/01/2023] Open
Abstract
Epilepsy comprises several syndromes, amongst the most common being mesial temporal lobe epilepsy with hippocampal sclerosis. Seizures in mesial temporal lobe epilepsy with hippocampal sclerosis are typically drug-resistant, and mesial temporal lobe epilepsy with hippocampal sclerosis is frequently associated with important co-morbidities, mandating the search for better understanding and treatment. The cause of mesial temporal lobe epilepsy with hippocampal sclerosis is unknown, but there is an association with childhood febrile seizures. Several rarer epilepsies featuring febrile seizures are caused by mutations in SCN1A, which encodes a brain-expressed sodium channel subunit targeted by many anti-epileptic drugs. We undertook a genome-wide association study in 1018 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 7552 control subjects, with validation in an independent sample set comprising 959 people with mesial temporal lobe epilepsy with hippocampal sclerosis and 3591 control subjects. To dissect out variants related to a history of febrile seizures, we tested cases with mesial temporal lobe epilepsy with hippocampal sclerosis with (overall n = 757) and without (overall n = 803) a history of febrile seizures. Meta-analysis revealed a genome-wide significant association for mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures at the sodium channel gene cluster on chromosome 2q24.3 [rs7587026, within an intron of the SCN1A gene, P = 3.36 × 10(-9), odds ratio (A) = 1.42, 95% confidence interval: 1.26-1.59]. In a cohort of 172 individuals with febrile seizures, who did not develop epilepsy during prospective follow-up to age 13 years, and 6456 controls, no association was found for rs7587026 and febrile seizures. These findings suggest SCN1A involvement in a common epilepsy syndrome, give new direction to biological understanding of mesial temporal lobe epilepsy with hippocampal sclerosis with febrile seizures, and open avenues for investigation of prognostic factors and possible prevention of epilepsy in some children with febrile seizures.
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Affiliation(s)
- Dalia Kasperavičiūtė
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Claudia B. Catarino
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
| | - Mar Matarin
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Costin Leu
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Jan Novy
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
| | - Anna Tostevin
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
| | - Bárbara Leal
- 3 Immunogenetics Laboratory, University of Porto, 4050-313 Porto, Portugal
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
| | - Ellen V. S. Hessel
- 5 Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, 3584 CG Utrecht, The Netherlands
| | - Kerstin Hallmann
- 6 Department of Epileptology, University of Bonn, 53105 Bonn, Germany
- 7 Life & Brain Centre, University of Bonn, 53105 Bonn, Germany
| | - Michael S. Hildebrand
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Hans-Henrik M. Dahl
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Mina Ryten
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Daniah Trabzuni
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
- 11 Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, 11211, Saudi Arabia
| | - Adaikalavan Ramasamy
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
- 12 Department of Medical and Molecular Genetics, King’s College London, Guy's Hospital, London, SE1 9RT, UK
| | - Saud Alhusaini
- 13 Molecular and Cellular Therapeutics Department, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- 14 Brain Morphometry Laboratory, Neurophysics Department, Beaumont Hospital, Dublin 9, Ireland
| | - Colin P. Doherty
- 15 Department of Neurology, St James’ Hospital, Dublin 8, Ireland
| | - Thomas Dorn
- 16 Swiss Epilepsy Centre, 8008 Zurich, Switzerland
| | - Jörg Hansen
- 16 Swiss Epilepsy Centre, 8008 Zurich, Switzerland
| | | | | | - Dominik Zumsteg
- 18 Department of Neurology, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Susan Duncan
- 19 Edinburgh and South East Scotland Epilepsy Service, Western General Hospital Edinburgh, EH4 2XU, Scotland, UK
| | - Reetta K. Kälviäinen
- 20 Kuopio Epilepsy Centre, Kuopio University Hospital, 70211 Kuopio, Finland
- 21 Department of Neurology, Institute of Clinical Medicine, University of Eastern Finland, 70211 Kuopio, Finland
| | - Kai J. Eriksson
- 22 Paediatric Neurology Unit, Tampere University Hospital and Paediatric Research Centre, University of Tampere, 33521 Tampere, Finland
| | - Anne-Mari Kantanen
- 20 Kuopio Epilepsy Centre, Kuopio University Hospital, 70211 Kuopio, Finland
| | - Massimo Pandolfo
- 23 Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | | | - Kurt Schlachter
- 25 Department of Paediatrics, LKH Bregenz, 6900 Bregenz, Austria
| | - Eva M. Reinthaler
- 26 Department of Clinical Neurology, Medical University of Vienna, 1090 Vienna, Austria
| | - Elisabeth Stogmann
- 26 Department of Clinical Neurology, Medical University of Vienna, 1090 Vienna, Austria
| | - Fritz Zimprich
- 26 Department of Clinical Neurology, Medical University of Vienna, 1090 Vienna, Austria
| | - Emilie Théâtre
- 27 Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA-R) and Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
- 28 Unit of Gastroenterology, Centre Hospitalier Universitaire, University of Liège, 4000 Liège, Belgium
| | - Colin Smith
- 29 Department of Neuropathology, MRC Sudden Death Brain Bank Project, University of Edinburgh, Wilkie Building, Edinburgh, EH8 9AG, UK
| | - Terence J. O’Brien
- 30 Departments of Medicine and Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne VIC 3050, Australia
- 31 Melbourne Brain Centre, University of Melbourne, Melbourne VIC 3084, Australia
| | - K. Meng Tan
- 30 Departments of Medicine and Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne VIC 3050, Australia
- 31 Melbourne Brain Centre, University of Melbourne, Melbourne VIC 3084, Australia
| | - Slave Petrovski
- 30 Departments of Medicine and Neurology, Royal Melbourne Hospital, University of Melbourne, Melbourne VIC 3050, Australia
- 31 Melbourne Brain Centre, University of Melbourne, Melbourne VIC 3084, Australia
- 32 Department of Medicine, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Angela Robbiano
- 33 Department of Neurosciences, Laboratory of Neurogenetics, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Roberta Paravidino
- 33 Department of Neurosciences, Laboratory of Neurogenetics, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Federico Zara
- 33 Department of Neurosciences, Laboratory of Neurogenetics, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Pasquale Striano
- 34 Paediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, ‘G. Gaslini’ Institute, 16147 Genova, Italy
| | - Michael R. Sperling
- 35 Department of Neurology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Russell J. Buono
- 36 Department of Biomedical Science, Cooper Medical School of Rowan University, Camden, NJ 08103, USA
| | - Hakon Hakonarson
- 37 Centre for Applied Genomics, The Children’s Hospital of Philadelphia, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104-4318, USA
| | - João Chaves
- 38 Department of Neurological Disorders and Senses, Hospital Santo António / Centro Hospitalar do Porto, 4099-001 Porto, Portugal
| | - Paulo P. Costa
- 3 Immunogenetics Laboratory, University of Porto, 4050-313 Porto, Portugal
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
- 39 Instituto Nacional de Saúde Dr. Ricardo Jorge (INSA), 4049-019 Porto, Portugal
| | - Berta M. Silva
- 3 Immunogenetics Laboratory, University of Porto, 4050-313 Porto, Portugal
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
| | - António M. da Silva
- 4 UMIB - Instituto Ciências Biomédicas Abel Salazar, University of Porto, 4099-003 Porto, Portugal
- 38 Department of Neurological Disorders and Senses, Hospital Santo António / Centro Hospitalar do Porto, 4099-001 Porto, Portugal
| | - Pierre N. E. de Graan
- 5 Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Centre Utrecht, 3584 CG Utrecht, The Netherlands
| | - Bobby P. C. Koeleman
- 40 Department of Medical Genetics, University Medical Centre Utrecht, 3584 CG Utrecht, The Netherlands
| | - Albert Becker
- 41 Department of Neuropathology, University of Bonn, 53105 Bonn, Germany
| | - Susanne Schoch
- 41 Department of Neuropathology, University of Bonn, 53105 Bonn, Germany
| | - Marec von Lehe
- 42 Department of Neurosurgery, University of Bochum, 44892 Bochum, Germany
| | - Philipp S. Reif
- 43 Epilepsy-Centre Hessen, Department of Neurology, University Hospitals and Philipps-University Marburg, 35043 Marburg, Germany
| | - Felix Rosenow
- 43 Epilepsy-Centre Hessen, Department of Neurology, University Hospitals and Philipps-University Marburg, 35043 Marburg, Germany
| | - Felicitas Becker
- 44 Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Yvonne Weber
- 44 Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Holger Lerche
- 44 Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tübingen, 72076 Tübingen, Germany
| | - Karl Rössler
- 45 Department of Neurosurgery, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Michael Buchfelder
- 45 Department of Neurosurgery, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Hajo M. Hamer
- 46 Department of Neurology, Epilepsy Centre, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Katja Kobow
- 47 Department of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Roland Coras
- 47 Department of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Ingmar Blumcke
- 47 Department of Neuropathology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Ingrid E. Scheffer
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
- 48 Florey Institute of Neuroscience and Mental Health, Melbourne VIC 3010, Australia
- 49 Department of Paediatrics, University of Melbourne, Royal Children’s Hospital, Melbourne VIC 3052, Australia
| | - Samuel F. Berkovic
- 8 Epilepsy Research Centre, Austin Health, University of Melbourne, Melbourne VIC 3084, Australia
| | - Michael E. Weale
- 12 Department of Medical and Molecular Genetics, King’s College London, Guy's Hospital, London, SE1 9RT, UK
| | - UK Brain Expression Consortium
- 9 Department of Molecular Neuroscience, UCL Institute of Neurology, London, WC1N 3BG, UK
- 10 Reta Lila Weston Institute, UCL Institute of Neurology, London, WC1N 3BG, UK
| | - Norman Delanty
- 13 Molecular and Cellular Therapeutics Department, Royal College of Surgeons in Ireland, Dublin 2, Ireland
- 50 Department of Neurology, Beaumont Hospital, Dublin 9, Ireland
| | - Chantal Depondt
- 23 Department of Neurology, Hôpital Erasme, Université Libre de Bruxelles, 1070 Brussels, Belgium
| | - Gianpiero L. Cavalleri
- 13 Molecular and Cellular Therapeutics Department, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - Wolfram S. Kunz
- 6 Department of Epileptology, University of Bonn, 53105 Bonn, Germany
- 7 Life & Brain Centre, University of Bonn, 53105 Bonn, Germany
| | - Sanjay M. Sisodiya
- 1 NIHR University College London Hospitals Biomedical Research Centre, Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
- 2 Epilepsy Society, Chalfont-St-Peter, SL9 0RJ, UK
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Leonard AS, Hyder SN, Kolls BJ, Arehart E, Ng KCW, Veerapandiyan A, Mikati MA. Seizure predisposition after perinatal hypoxia: effects of subsequent age and of an epilepsy predisposing gene mutation. Epilepsia 2013; 54:1789-800. [PMID: 24032507 DOI: 10.1111/epi.12347] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2013] [Indexed: 02/06/2023]
Abstract
PURPOSE There is a gap in our knowledge of the factors that modulate the predisposition to seizures following perinatal hypoxia. Herein, we investigate in a mouse model the effects of two distinct factors: developmental stage after the occurrence of the perinatal insult, and the presence of a seizure predisposing mutation. METHODS Effects of age: P6 (postnatal day 6) mouse pups were subjected to acute hypoxia down to 4% O2 over the course of 45 min. Seizure susceptibilities to flurothyl-induced seizures (single exposures) and to flurothyl kindling were determined at specific subsequent ages. Effects of mutation: Heterozygote mice, with deletion of one copy of the Kcn1a gene, subjected to P6 hypoxia were compared as adults to wild-type mice with respect to susceptibility to a single exposure to flurothyl and to the occurrence of spontaneous seizures as detected by hippocampal electroencephalography (EEG) and video recordings. KEY FINDINGS Effects of age: As compared to controls, wild-type mice exposed to P6 hypoxia had a shortened seizure latency in response to a single flurothyl exposure at P50, but not at P7 or P28 (p < 0.04). In addition, perinatal hypoxia at P6 enhanced the rate of development of flurothyl kindling performed at P28-38 (p < 0.03), but not at P7-17. Effects of mutation: Kcn1a heterozygous mice subjected to P6 hypoxia exhibited increased susceptibility to flurothyl-induced seizures at P50 as compared to Normoxia heterozygote littermates, and to wild-type Hypoxia and Normoxia mice. In addition, heterozygotes exposed to P6 hypoxia were the only group in which spontaneous seizures were detected during the period of long-term monitoring (p < 0.027 in all comparisons). SIGNIFICANCE Our data establish a mouse model of mild perinatal hypoxia in which we document the following: (1) the emergence, after a latent period, of increased susceptibility to flurothyl-induced seizures, and to flurothyl induced kindling; and (2) an additive effect of a gene mutation to the seizure predisposing consequences of perinatal hypoxia, thereby demonstrating that a modifier (or susceptibility) gene can exacerbate the long-term consequences of hypoxic injury.
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Affiliation(s)
- A Soren Leonard
- Division of Pediatric Neurology, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, U.S.A
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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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Allen AS, Berkovic SF, Cossette P, Delanty N, Dlugos D, Eichler EE, Epstein MP, Glauser T, Goldstein DB, Han Y, Heinzen EL, Hitomi Y, Howell KB, Johnson MR, Kuzniecky R, Lowenstein DH, Lu YF, Madou MRZ, Marson AG, Mefford HC, Esmaeeli Nieh S, O'Brien TJ, Ottman R, Petrovski S, Poduri A, Ruzzo EK, Scheffer IE, Sherr EH, Yuskaitis CJ, Abou-Khalil B, Alldredge BK, Bautista JF, Berkovic SF, Boro A, Cascino GD, Consalvo D, Crumrine P, Devinsky O, Dlugos D, Epstein MP, Fiol M, Fountain NB, French J, Friedman D, Geller EB, Glauser T, Glynn S, Haut SR, Hayward J, Helmers SL, Joshi S, Kanner A, Kirsch HE, Knowlton RC, Kossoff EH, Kuperman R, Kuzniecky R, Lowenstein DH, McGuire SM, Motika PV, Novotny EJ, Ottman R, Paolicchi JM, Parent JM, Park K, Poduri A, Scheffer IE, Shellhaas RA, Sherr EH, Shih JJ, Singh R, Sirven J, Smith MC, Sullivan J, Lin Thio L, Venkat A, Vining EPG, Von Allmen GK, Weisenberg JL, Widdess-Walsh P, Winawer MR. De novo mutations in epileptic encephalopathies. Nature 2013; 501:217-21. [PMID: 23934111 PMCID: PMC3773011 DOI: 10.1038/nature12439] [Citation(s) in RCA: 1123] [Impact Index Per Article: 102.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2013] [Accepted: 07/09/2013] [Indexed: 12/21/2022]
Abstract
Epileptic encephalopathies are a devastating group of severe childhood epilepsy disorders for which the cause is often unknown. Here we report a screen for de novo mutations in patients with two classical epileptic encephalopathies: infantile spasms (n = 149) and Lennox-Gastaut syndrome (n = 115). We sequenced the exomes of 264 probands, and their parents, and confirmed 329 de novo mutations. A likelihood analysis showed a significant excess of de novo mutations in the ∼4,000 genes that are the most intolerant to functional genetic variation in the human population (P = 2.9 × 10(-3)). Among these are GABRB3, with de novo mutations in four patients, and ALG13, with the same de novo mutation in two patients; both genes show clear statistical evidence of association with epileptic encephalopathy. Given the relevant site-specific mutation rates, the probabilities of these outcomes occurring by chance are P = 4.1 × 10(-10) and P = 7.8 × 10(-12), respectively. Other genes with de novo mutations in this cohort include CACNA1A, CHD2, FLNA, GABRA1, GRIN1, GRIN2B, HNRNPU, IQSEC2, MTOR and NEDD4L. Finally, we show that the de novo mutations observed are enriched in specific gene sets including genes regulated by the fragile X protein (P < 10(-8)), as has been reported previously for autism spectrum disorders.
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CYP3A5*3 and C3435T MDR1 polymorphisms in prognostication of drug-resistant epilepsy in children and adolescents. BIOMED RESEARCH INTERNATIONAL 2013; 2013:526837. [PMID: 23984379 PMCID: PMC3747339 DOI: 10.1155/2013/526837] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 06/25/2013] [Indexed: 01/13/2023]
Abstract
Drug-resistant epilepsies still remain one of the most profound problems of contemporary epileptology. Several mechanisms of drug resistance are possible; among them, genetic factors have a prominent place. Much importance is attached to genes, which encode enzymes that metabolize antiepileptic drugs CYP 3A, which belong to the family of cytochromes P450 and the genome of multidrug resistance, such as multidrug resistance 1 (MDR1) that expresses P-glycoprotein (P-gp), a drug transporter protein. The aim of the study was to assess the relation between polymorphism of gene CYP3A5 and polymorphism C3435T of MDR1 gene with the occurrence of focal, drug-resistant epilepsy in children and youths up to 18 years of age. The study comprised 85 patients, and their age range was from 33 months to 18 years of age, suffering from epilepsy, partly responding well to treatment, partly drug resistant. The polymorphism of both genes has been analysed using the PCR-RFLP method. The study failed to corroborate association between polymorphism CYP3A5∗3 and C3435T polymorphism in MDR1 gene and pharmacoresistant epilepsy. The results of our research do not confirm the prognostic value of the polymorphisms examined in the prognostication of drug resistance in epilepsies.
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Buono RJ. Genome wide association studies (GWAS) and common forms of human epilepsy. Epilepsy Behav 2013; 28 Suppl 1:S63-5. [PMID: 23756483 PMCID: PMC3682226 DOI: 10.1016/j.yebeh.2012.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Accepted: 07/11/2012] [Indexed: 11/25/2022]
Abstract
Several GWAS focused on common forms of epilepsy are underway. Currently, only one locus has been published that reached genome wide statistical significance. Two other loci that also reach genome wide statistical significance have been reported as preliminary data and are awaiting publication. Several additional loci identified in these studies fall just short of statistical significance, and it is hoped that future large scale meta-analyses will confirm these early findings and identify new loci that influence common forms of human epilepsy. Next generation DNA sequencing (NGS) studies are also underway and in the future will identify rare DNA variations of large effect that also contribute to the final epilepsy phenotypes under study. Finally, these studies have the potential to identify biomarkers of antiepileptic drug (AED) response as epilepsy patient GWAS and NGS data are stratified based on AED efficacy and tolerability.
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71
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Helbig I, Hartmann C, Mefford HC. The unexpected role of copy number variations in juvenile myoclonic epilepsy. Epilepsy Behav 2013; 28 Suppl 1:S66-8. [PMID: 23756484 DOI: 10.1016/j.yebeh.2012.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 07/09/2012] [Indexed: 01/28/2023]
Abstract
Structural genomic variants or copy number variants (CNVs) comprise submicroscopic deletions and duplications of chromosomal material, including both rearrangements at genomic hotspots as well as duplications and deletions with unique breakpoints. Copy number variants have increasingly been recognized in the Idiopathic/Genetic Generalized Epilepsies (IGE/GGE) including juvenile myoclonic epilepsy (JME). Microdeletions at 15q13.3, 15q11.2, and 16p13.11 are genetic risk factors that can be identified in 3% of patients with IGE including JME. These microdeletions, however, also represent genetic risk factors to a broad range of other neurodevelopmental disorders. Additionally, 6% of patients with GGE carry other, potentially pathogenic structural genomic variants. While family studies largely support the channelopathy concept of the idiopathic epilepsies, the results of studies investigating copy number variations suggest that JME genetically overlaps with a broad range of other neurodevelopmental disorders. In addition, the particular genetic properties of structural genomic variations as rare genetic variants highlight the complexity of the genetic architecture of human disease.
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Affiliation(s)
- Ingo Helbig
- Department of Neuropediatrics, University Medical Center Schleswig-Holstein, Christian-Albrechts University, Kiel, Germany.
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Abou-Khalil B, Alldredge B, Bautista J, Berkovic S, Bluvstein J, Boro A, Cascino G, Consalvo D, Cristofaro S, Crumrine P, Devinsky O, Dlugos D, Epstein M, Fahlstrom R, Fiol M, Fountain N, Fox K, French J, Freyer Karn C, Friedman D, Geller E, Glauser T, Glynn S, Haas K, Haut S, Hayward J, Helmers S, Joshi S, Kanner A, Kirsch H, Knowlton R, Kossoff E, Kuperman R, Kuzniecky R, Lowenstein D, McGuire S, Motika P, Nesbitt G, Novotny E, Ottman R, Paolicchi J, Parent J, Park K, Poduri A, Risch N, Sadleir L, Scheffer I, Shellhaas R, Sherr E, Shih JJ, Shinnar S, Singh R, Sirven J, Smith M, Sullivan J, Thio LL, Venkat A, Vining E, von Allmen G, Weisenberg J, Widdess-Walsh P, Winawer M. The epilepsy phenome/genome project. Clin Trials 2013; 10:568-86. [PMID: 23818435 DOI: 10.1177/1740774513484392] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Epilepsy is a common neurological disorder that affects approximately 50 million people worldwide. Both risk of epilepsy and response to treatment partly depend on genetic factors, and gene identification is a promising approach to target new prediction, treatment, and prevention strategies. However, despite significant progress in the identification of genes causing epilepsy in families with a Mendelian inheritance pattern, there is relatively little known about the genetic factors responsible for common forms of epilepsy and so-called epileptic encephalopathies. Study design The Epilepsy Phenome/Genome Project (EPGP) is a multi-institutional, retrospective phenotype-genotype study designed to gather and analyze detailed phenotypic information and DNA samples on 5250 participants, including probands with specific forms of epilepsy and, in a subset, parents of probands who do not have epilepsy. RESULTS EPGP is being executed in four phases: study initiation, pilot, study expansion/establishment, and close-out. This article discusses a number of key challenges and solutions encountered during the first three phases of the project, including those related to (1) study initiation and management, (2) recruitment and phenotyping, and (3) data validation. The study has now enrolled 4223 participants. CONCLUSIONS EPGP has demonstrated the value of organizing a large network into cores with specific roles, managed by a strong Administrative Core that utilizes frequent communication and a collaborative model with tools such as study timelines and performance-payment models. The study also highlights the critical importance of an effective informatics system, highly structured recruitment methods, and expert data review.
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Abstract
Dystonia is a common movement disorder seen by neurologists in clinic. Genetic forms of the disease are important to recognize clinically and also provide valuable information about possible pathogenic mechanisms within the wider disorder. In the past few years, with the advent of new sequencing technologies, there has been a step change in the pace of discovery in the field of dystonia genetics. In just over a year, four new genes have been shown to cause primary dystonia (CIZ1, ANO3, TUBB4A and GNAL), PRRT2 has been identified as the cause of paroxysmal kinesigenic dystonia and other genes, such as SLC30A10 and ATP1A3, have been linked to more complicated forms of dystonia or new phenotypes. In this review, we provide an overview of the current state of knowledge regarding genetic forms of dystonia—related to both new and well-known genes alike—and incorporating genetic, clinical and molecular information. We discuss the mechanistic insights provided by the study of the genetic causes of dystonia and provide a helpful clinical algorithm to aid clinicians in correctly predicting the genetic basis of various forms of dystonia.
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Affiliation(s)
- Gavin Charlesworth
- Department of Molecular Neuroscience, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
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Williams CA, Battaglia A. Molecular biology of epilepsy genes. Exp Neurol 2013; 244:51-8. [DOI: 10.1016/j.expneurol.2011.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 11/28/2011] [Accepted: 12/01/2011] [Indexed: 01/05/2023]
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Kumari R, Lakhan R, Kumar S, Garg R, Misra U, Kalita J, Mittal B. SCN1AIVS5-91G>A polymorphism is associated with susceptibility to epilepsy but not with drug responsiveness. Biochimie 2013; 95:1350-3. [DOI: 10.1016/j.biochi.2013.02.006] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 02/04/2013] [Indexed: 10/27/2022]
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Bakir-Gungor B, Baykan B, Ugur İseri S, Tuncer FN, Sezerman OU. Identifying SNP targeted pathways in partial epilepsies with genome-wide association study data. Epilepsy Res 2013; 105:92-102. [PMID: 23498093 DOI: 10.1016/j.eplepsyres.2013.02.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2012] [Revised: 01/15/2013] [Accepted: 02/13/2013] [Indexed: 12/18/2022]
Abstract
PURPOSE In a recent genome-wide association study for partial epilepsies in the European population, a common genetic variation has been reported to affect partial epilepsy only modestly. However, in complex diseases such as partial epilepsy, multiple factors (e.g. single nucleotide polymorphisms, microRNAs, metabolic and epigenetic factors) may target different sets of genes in the same pathway, affecting its function and thus causing the disease development. In this regard, we hypothesize that the pathways are critical for elucidating the mechanisms underlying partial epilepsy. METHODS Previously we had developed a novel methodology with the aim of identifying the disease-related pathways. We had combined evidence of genetic association with current knowledge of (i) biochemical pathways, (ii) protein-protein interaction networks, and (iii) the functional information of selected single nucleotide polymorphisms. In our present study, we apply this methodology to a data set on partial epilepsy, including 3445 cases and 6935 controls of European ancestry. RESULTS We have identified 30 overrepresented pathways with corrected p-values smaller than 10(-12). These pathways include complement and coagulation cascades, cell cycle, focal adhesion, extra cellular matrix-receptor interaction, JAK-STAT signaling pathway, MAPK signaling pathway, proteasome, ribosome, calcium signaling and regulation of actin cytoskeleton pathways. Most of these pathways have growing scientific support in the literature as being associated with partial epilepsy. We also demonstrate that different factors affect distinct parts of the pathways, as shown here on complement and coagulation cascades pathway with a comparison of gene expression vs. genome-wide association study. CONCLUSIONS Traditional studies on genome-wide association have not revealed strong associations in epilepsies, since these single nucleotide polymorphisms are not shared by most of the patients. Our results suggest that it is more effective to incorporate the functional effect of a single nucleotide polymorphism on the gene product, protein-protein interaction networks and functional enrichment tools into genome-wide association studies. These can then be used to determine leading molecular pathways, which cannot be detected through traditional analyses. We hope that this type of analysis brings the research community one step closer to unraveling the complex genetic structure of epilepsies.
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Affiliation(s)
- B Bakir-Gungor
- Department of Genetics and Bioinformatics, Faculty of Arts and Sciences, Bahcesehir University, Ciragan Cad. Osmanpasa Mektebi Sok., No.: 4, 34353, Besiktas, Istanbul, Turkey.
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Unraveling the genetics of common epilepsies: approaches, platforms, and caveats. Epilepsy Behav 2013; 26:229-33. [PMID: 23103323 DOI: 10.1016/j.yebeh.2012.09.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2012] [Accepted: 09/13/2012] [Indexed: 11/21/2022]
Abstract
With no known intervention to prevent or cure epilepsy, treatment is primarily symptomatic and requires long-term administration of medications to suppress seizure occurrence. Current antiepileptic drugs (AEDs) are ineffective in one-third of patients (Kwan and Brodie, 2000). Such therapeutic inadequacy is largely due to our insufficient understanding of the basic molecular pathophysiological processes that underlie epileptogenesis. Breakthroughs are needed in the identification of new molecular targets that will translate to novel intervention approaches. Discovering genetic variants that increase the susceptibility to disease is a promising avenue to identifying such targets. However, early candidate gene-based studies in epilepsy proved ineffective in identifying genetic risk factors for the non-Mendelian, complex epilepsies, which represent >95% of clinically encountered epilepsy. Furthermore, genome-wide association studies (GWAS) of epilepsy patients have been largely negative, with the exception of several putative susceptibility loci discovered in Han Chinese focal epilepsy and European Caucasian GGE patients (Kasperaviciute et al., 2010; Guo et al., 2012; Consortium et al., 2012). Results of these GWAS suggest that, similar to other common diseases, associations with common single nucleotide variants (SNV) appear likely to account for a small fraction of the heritability of epilepsy, thus fuelling the effort to also search for alternative genetic contributors, with a recent increased emphasis on rare variants with larger effects (Manolio et al., 2009). It is possible that both common and rare variants contribute to an increased susceptibility to common epilepsy syndromes (Mulley et al., 2005). We review the approaches that have been taken to identify genetic risk markers of the common epilepsy syndromes, the experimental platforms, and their caveats. We discuss current technologies and analytical frameworks that might expedite the discovery of these variants by leveraging advances in microarray-based, high-throughput, genotyping technology, and complementary interdisciplinary expertise of study teams including the need for meta-analyses under global collaborative frameworks. We briefly discuss the analytical options made available through rapid advances in sequencing and other genomic technologies.
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Abstract
Over the past year huge advances have been made in our ability to determine the genetic aetiology of many neurological diseases through the utilisation of next generation sequencing platforms. This technology is, on a daily basis, providing new breakthroughs in neurological disease. The aim of this article is to clearly describe the technological platforms, methods of data analysis, established breakthroughs, and potential future clinical and research applications of this innovative and exciting technique which has relevance to all those working within clinical neuroscience.
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Affiliation(s)
- M J Keogh
- Mitochondrial Research Group, Newcastle University, UK
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SLC6A4 gene variants and temporal lobe epilepsy susceptibility: a meta-analysis. Mol Biol Rep 2012; 39:10615-9. [DOI: 10.1007/s11033-012-1949-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 10/01/2012] [Indexed: 12/17/2022]
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Steffens M, Leu C, Ruppert AK, Zara F, Striano P, Robbiano A, Capovilla G, Tinuper P, Gambardella A, Bianchi A, La Neve A, Crichiutti G, de Kovel CGF, Kasteleijn-Nolst Trenité D, de Haan GJ, Lindhout D, Gaus V, Schmitz B, Janz D, Weber YG, Becker F, Lerche H, Steinhoff BJ, Kleefuß-Lie AA, Kunz WS, Surges R, Elger CE, Muhle H, von Spiczak S, Ostertag P, Helbig I, Stephani U, Møller RS, Hjalgrim H, Dibbens LM, Bellows S, Oliver K, Mullen S, Scheffer IE, Berkovic SF, Everett KV, Gardiner MR, Marini C, Guerrini R, Lehesjoki AE, Siren A, Guipponi M, Malafosse A, Thomas P, Nabbout R, Baulac S, Leguern E, Guerrero R, Serratosa JM, Reif PS, Rosenow F, Mörzinger M, Feucht M, Zimprich F, Kapser C, Schankin CJ, Suls A, Smets K, De Jonghe P, Jordanova A, Caglayan H, Yapici Z, Yalcin DA, Baykan B, Bebek N, Ozbek U, Gieger C, Wichmann HE, Balschun T, Ellinghaus D, Franke A, Meesters C, Becker T, Wienker TF, Hempelmann A, Schulz H, Rüschendorf F, Leber M, Pauck SM, Trucks H, Toliat MR, Nürnberg P, Avanzini G, Koeleman BPC, Sander T. Genome-wide association analysis of genetic generalized epilepsies implicates susceptibility loci at 1q43, 2p16.1, 2q22.3 and 17q21.32. Hum Mol Genet 2012; 21:5359-72. [PMID: 22949513 DOI: 10.1093/hmg/dds373] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Genetic generalized epilepsies (GGEs) have a lifetime prevalence of 0.3% and account for 20-30% of all epilepsies. Despite their high heritability of 80%, the genetic factors predisposing to GGEs remain elusive. To identify susceptibility variants shared across common GGE syndromes, we carried out a two-stage genome-wide association study (GWAS) including 3020 patients with GGEs and 3954 controls of European ancestry. To dissect out syndrome-related variants, we also explored two distinct GGE subgroups comprising 1434 patients with genetic absence epilepsies (GAEs) and 1134 patients with juvenile myoclonic epilepsy (JME). Joint Stage-1 and 2 analyses revealed genome-wide significant associations for GGEs at 2p16.1 (rs13026414, P(meta) = 2.5 × 10(-9), OR[T] = 0.81) and 17q21.32 (rs72823592, P(meta) = 9.3 × 10(-9), OR[A] = 0.77). The search for syndrome-related susceptibility alleles identified significant associations for GAEs at 2q22.3 (rs10496964, P(meta) = 9.1 × 10(-9), OR[T] = 0.68) and at 1q43 for JME (rs12059546, P(meta) = 4.1 × 10(-8), OR[G] = 1.42). Suggestive evidence for an association with GGEs was found in the region 2q24.3 (rs11890028, P(meta) = 4.0 × 10(-6)) nearby the SCN1A gene, which is currently the gene with the largest number of known epilepsy-related mutations. The associated regions harbor high-ranking candidate genes: CHRM3 at 1q43, VRK2 at 2p16.1, ZEB2 at 2q22.3, SCN1A at 2q24.3 and PNPO at 17q21.32. Further replication efforts are necessary to elucidate whether these positional candidate genes contribute to the heritability of the common GGE syndromes.
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Affiliation(s)
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- Institute for Medical Biometry, Informatic and Epidemiology, University of Bonn, Bonn, Germany
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Abstract
Current and emerging technologies for mutation identification are changing the landscape of genetics and accelerating the pace of discovery. Application of high throughput genomic analysis to epilepsy will advance our understanding of the genetic contribution to common forms of epilepsy and suggest novel therapeutic strategies for improved treatment.
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Scanlon C, Ronan L, Doherty CP, Cavalleri GL, Tirupati S, Alhusaini S, Maguire S, Delanty N, Iyer PM, Chaila E, Fitzsimons M. MRI-based brain structure volumes in temporal lobe epilepsy patients and their unaffected siblings: a preliminary study. J Neuroimaging 2012; 23:64-70. [PMID: 22928655 DOI: 10.1111/j.1552-6569.2012.00736.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
INTRODUCTION Investigating the heritability of brain structure may be useful in simplifying complicated genetic studies in temporal lobe epilepsy (TLE). A preliminary study is presented to determine if volume deficits of candidate brain structures present at a higher rate in unaffected siblings than controls subjects. METHODS T1-weighted MR images was acquired for 28 TLE patients, a same-sex unaffected sibling of 12 of these and 28 normal controls. Selected brain structure volumes were measured using an automated whole brain segmentation technique. Candidate brain structure endophenotypes were determined and group differences were investigated between (1) controls and patients and (2) controls and siblings. ICC's were used to measure the quantitative volumetric association within each sibling pair. RESULTS TLE patients demonstrated a significantly lower cerebral white matter, bilateral hippocampus, thalamus, and left entorhinal cortex volumes when compared with controls. A significant deficit in cerebral white matter (CWM) was common to patient and nonaffected siblings when compared with controls. Furthermore, a significant correlation was revealed between patients and siblings in CWM and bilateral thalamus. CONCLUSION The findings suggest an overlap in the neurodevelopmental genes responsible for both brain structure and the expression of the disease. Further work is ongoing to confirm these findings.
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Affiliation(s)
- Cathy Scanlon
- Brain Morphometry Laboratory, Epilepsy Programme, Beaumont Hospital, Dublin, Ireland
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Abstract
A major challenge in epilepsy research is to unravel the complex genetic mechanisms underlying both common and rare forms of epilepsy, as well as the genetic determinants of response to treatment. To accelerate progress in this area, the National Institute of Neurological Disorders and Stroke (NINDS) recently offered funding for the creation of a “Center without Walls” to focus on the genetics of human epilepsy. This article describes Epi4K, the collaborative study supported through this grant mechanism and having the aim of analyzing the genomes of a minimum 4,000 subjects with highly selected and well-characterized epilepsy.
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Affiliation(s)
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- Center for Human Genome Variation, Duke University, Durham, North Carolina 27708, USA
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Nelson MR, Wegmann D, Ehm MG, Kessner D, St Jean P, Verzilli C, Shen J, Tang Z, Bacanu SA, Fraser D, Warren L, Aponte J, Zawistowski M, Liu X, Zhang H, Zhang Y, Li J, Li Y, Li L, Woollard P, Topp S, Hall MD, Nangle K, Wang J, Abecasis G, Cardon LR, Zöllner S, Whittaker JC, Chissoe SL, Novembre J, Mooser V. An abundance of rare functional variants in 202 drug target genes sequenced in 14,002 people. Science 2012; 337:100-4. [PMID: 22604722 DOI: 10.1126/science.1217876] [Citation(s) in RCA: 483] [Impact Index Per Article: 40.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Rare genetic variants contribute to complex disease risk; however, the abundance of rare variants in human populations remains unknown. We explored this spectrum of variation by sequencing 202 genes encoding drug targets in 14,002 individuals. We find rare variants are abundant (1 every 17 bases) and geographically localized, so that even with large sample sizes, rare variant catalogs will be largely incomplete. We used the observed patterns of variation to estimate population growth parameters, the proportion of variants in a given frequency class that are putatively deleterious, and mutation rates for each gene. We conclude that because of rapid population growth and weak purifying selection, human populations harbor an abundance of rare variants, many of which are deleterious and have relevance to understanding disease risk.
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Affiliation(s)
- Matthew R Nelson
- Department of Quantitative Sciences, GlaxoSmithKline (GSK), Research Triangle Park, NC 27709, USA.
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Stein JL, Medland SE, Vasquez AA, Hibar DP, Senstad RE, Winkler AM, Toro R, Appel K, Bartecek R, Bergmann Ø, Bernard M, Brown AA, Cannon DM, Chakravarty MM, Christoforou A, Domin M, Grimm O, Hollinshead M, Holmes AJ, Homuth G, Hottenga JJ, Langan C, Lopez LM, Hansell NK, Hwang KS, Kim S, Laje G, Lee PH, Liu X, Loth E, Lourdusamy A, Mattingsdal M, Mohnke S, Maniega SM, Nho K, Nugent AC, O'Brien C, Papmeyer M, Pütz B, Ramasamy A, Rasmussen J, Rijpkema M, Risacher SL, Roddey JC, Rose EJ, Ryten M, Shen L, Sprooten E, Strengman E, Teumer A, Trabzuni D, Turner J, van Eijk K, van Erp TGM, van Tol MJ, Wittfeld K, Wolf C, Woudstra S, Aleman A, Alhusaini S, Almasy L, Binder EB, Brohawn DG, Cantor RM, Carless MA, Corvin A, Czisch M, Curran JE, Davies G, de Almeida MAA, Delanty N, Depondt C, Duggirala R, Dyer TD, Erk S, Fagerness J, Fox PT, Freimer NB, Gill M, Göring HHH, Hagler DJ, Hoehn D, Holsboer F, Hoogman M, Hosten N, Jahanshad N, Johnson MP, Kasperaviciute D, Kent JW, Kochunov P, Lancaster JL, Lawrie SM, Liewald DC, Mandl R, Matarin M, Mattheisen M, Meisenzahl E, Melle I, Moses EK, Mühleisen TW, Nauck M, Nöthen MM, Olvera RL, Pandolfo M, Pike GB, Puls R, Reinvang I, Rentería ME, Rietschel M, Roffman JL, Royle NA, Rujescu D, Savitz J, Schnack HG, Schnell K, Seiferth N, Smith C, Steen VM, Valdés Hernández MC, Van den Heuvel M, van der Wee NJ, Van Haren NEM, Veltman JA, Völzke H, Walker R, Westlye LT, Whelan CD, Agartz I, Boomsma DI, Cavalleri GL, Dale AM, Djurovic S, Drevets WC, Hagoort P, Hall J, Heinz A, Jack CR, Foroud TM, Le Hellard S, Macciardi F, Montgomery GW, Poline JB, Porteous DJ, Sisodiya SM, Starr JM, Sussmann J, Toga AW, Veltman DJ, Walter H, Weiner MW, Bis JC, Ikram MA, Smith AV, Gudnason V, Tzourio C, Vernooij MW, Launer LJ, DeCarli C, Seshadri S, Andreassen OA, Apostolova LG, Bastin ME, Blangero J, Brunner HG, Buckner RL, Cichon S, Coppola G, de Zubicaray GI, Deary IJ, Donohoe G, de Geus EJC, Espeseth T, Fernández G, Glahn DC, Grabe HJ, Hardy J, Hulshoff Pol HE, Jenkinson M, Kahn RS, McDonald C, McIntosh AM, McMahon FJ, McMahon KL, Meyer-Lindenberg A, Morris DW, Müller-Myhsok B, Nichols TE, Ophoff RA, Paus T, Pausova Z, Penninx BW, Potkin SG, Sämann PG, Saykin AJ, Schumann G, Smoller JW, Wardlaw JM, Weale ME, Martin NG, Franke B, Wright MJ, Thompson PM. Identification of common variants associated with human hippocampal and intracranial volumes. Nat Genet 2012; 44:552-61. [PMID: 22504417 PMCID: PMC3635491 DOI: 10.1038/ng.2250] [Citation(s) in RCA: 524] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2011] [Accepted: 03/19/2012] [Indexed: 02/06/2023]
Abstract
Identifying genetic variants influencing human brain structures may reveal new biological mechanisms underlying cognition and neuropsychiatric illness. The volume of the hippocampus is a biomarker of incipient Alzheimer's disease and is reduced in schizophrenia, major depression and mesial temporal lobe epilepsy. Whereas many brain imaging phenotypes are highly heritable, identifying and replicating genetic influences has been difficult, as small effects and the high costs of magnetic resonance imaging (MRI) have led to underpowered studies. Here we report genome-wide association meta-analyses and replication for mean bilateral hippocampal, total brain and intracranial volumes from a large multinational consortium. The intergenic variant rs7294919 was associated with hippocampal volume (12q24.22; N = 21,151; P = 6.70 × 10(-16)) and the expression levels of the positional candidate gene TESC in brain tissue. Additionally, rs10784502, located within HMGA2, was associated with intracranial volume (12q14.3; N = 15,782; P = 1.12 × 10(-12)). We also identified a suggestive association with total brain volume at rs10494373 within DDR2 (1q23.3; N = 6,500; P = 5.81 × 10(-7)).
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Affiliation(s)
- Jason L Stein
- Laboratory of Neuro Imaging, David Geffen School of Medicine, University of California, Los Angeles, California, USA
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Coe BP, Girirajan S, Eichler EE. The genetic variability and commonality of neurodevelopmental disease. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:118-29. [PMID: 22499536 PMCID: PMC4114147 DOI: 10.1002/ajmg.c.31327] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Despite detailed clinical definition and refinement of neurodevelopmental disorders and neuropsychiatric conditions, the underlying genetic etiology has proved elusive. Recent genetic studies have revealed some common themes: considerable locus heterogeneity, variable expressivity for the same mutation, and a role for multiple disruptive events in the same individual affecting genes in common pathways. Recurrent copy number variation (CNV), in particular, has emphasized the importance of either de novo or essentially private mutations creating imbalances for multiple genes. CNVs have foreshadowed a model where the distinction between milder neuropsychiatric conditions from those of severe developmental impairment may be a consequence of increased mutational burden affecting more genes.
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Affiliation(s)
- Bradley P Coe
- Department of Genome Sciences and Howard Hughes Medical Institute, University of Washington School of Medicine, Seattle, WA, USA
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87
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Rubio JP, Topp S, Warren L, St Jean PL, Wegmann D, Kessner D, Novembre J, Shen J, Fraser D, Aponte J, Nangle K, Cardon LR, Ehm MG, Chissoe SL, Whittaker JC, Nelson MR, Mooser VE. Deep sequencing of the LRRK2 gene in 14,002 individuals reveals evidence of purifying selection and independent origin of the p.Arg1628Pro mutation in Europe. Hum Mutat 2012; 33:1087-98. [PMID: 22415848 DOI: 10.1002/humu.22075] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 02/24/2012] [Indexed: 12/12/2022]
Abstract
Genetic variation in LRRK2 predisposes to Parkinson disease (PD), which underpins its development as a therapeutic target. Here, we aimed to identify novel genotype-phenotype associations that might support developing LRRK2 therapies for other conditions. We sequenced the 51 exons of LRRK2 in cases comprising 12 common diseases (n = 9,582), and in 4,420 population controls. We identified 739 single-nucleotide variants, 62% of which were observed in only one person, including 316 novel exonic variants. We found evidence of purifying selection for the LRRK2 gene and a trend suggesting that this is more pronounced in the central (ROC-COR-kinase) core protein domains of LRRK2 than the flanking domains. Population genetic analyses revealed that LRRK2 is not especially polymorphic or differentiated in comparison to 201 other drug target genes. Among Europeans, we identified 17 carriers (0.13%) of pathogenic LRRK2 mutations that were not significantly enriched within any disease or in those reporting a family history of PD. Analysis of pathogenic mutations within Europe reveals that the p.Arg1628Pro (c4883G>C) mutation arose independently in Europe and Asia. Taken together, these findings demonstrate how targeted deep sequencing can help to reveal fundamental characteristics of clinically important loci.
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Affiliation(s)
- Justin P Rubio
- Quantitative Sciences, Research and Development, GlaxoSmithKline, Gunnels Wood Road, Stevenage, Hertfordshire, England, United Kingdom.
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88
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Genetics of temporal lobe epilepsy: a review. EPILEPSY RESEARCH AND TREATMENT 2012; 2012:863702. [PMID: 22957248 PMCID: PMC3420533 DOI: 10.1155/2012/863702] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/27/2011] [Revised: 11/06/2011] [Accepted: 12/07/2011] [Indexed: 11/18/2022]
Abstract
Temporal lobe epilepsy (TLE) is usually regarded as a polygenic and complex disorder. To understand its genetic component, numerous linkage analyses of familial forms and association studies of cases versus controls have been conducted since the middle of the nineties. The present paper lists genetic findings for TLE from the initial segregation analysis to the most recent results published in May 2011. To date, no genes have been clearly related to TLE despite many efforts to do so. However, it is vital to continue replication studies and collaborative attempts to find significant results and thus determine which gene variant combination plays a definitive role in the aetiology of TLE.
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89
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Coller JK, Hutchinson MR. Implications of central immune signaling caused by drugs of abuse: mechanisms, mediators and new therapeutic approaches for prediction and treatment of drug dependence. Pharmacol Ther 2012; 134:219-45. [PMID: 22316499 DOI: 10.1016/j.pharmthera.2012.01.008] [Citation(s) in RCA: 137] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Accepted: 01/17/2012] [Indexed: 01/12/2023]
Abstract
In the past two decades a trickle of manuscripts examining the non-neuronal central nervous system immune consequences of the drugs of abuse has now swollen to a significant body of work. Initially, these studies reported associative evidence of central nervous system proinflammation resulting from exposure to the drugs of abuse demonstrating key implications for neurotoxicity and disease progression associated with, for example, HIV infection. However, more recently this drug-induced activation of central immune signaling is now understood to contribute substantially to the pharmacodynamic actions of the drugs of abuse, by enhancing the engagement of classical mesolimbic dopamine reward pathways and withdrawal centers. This review will highlight the key in vivo animal, human, biological and molecular evidence of these central immune signaling actions of opioids, alcohol, cocaine, methamphetamine, and 3,4-methylenedioxymethamphetamine (MDMA). Excitingly, this new appreciation of central immune signaling activity of drugs of abuse provides novel therapeutic interventions and opportunities to identify 'at risk' individuals through the use of immunogenetics. Discussion will also cover the evidence of modulation of this signaling by existing clinical and pre-clinical drug candidates, and novel pharmacological targets. Finally, following examination of the breadth of central immune signaling actions of the drugs of abuse highlighted here, the current known common immune signaling components will be outlined and their impact on established addiction neurocircuitry discussed, thereby synthesizing a common neuroimmune hypothesis of addiction.
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Affiliation(s)
- Janet K Coller
- Discipline of Pharmacology, School of Medical Sciences, University of Adelaide, South Australia 5005, Australia.
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90
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Abstract
Rather than being polygenic, complex disorders probably represent umbrella terms for collections of conditions caused by rare, recent mutations in any of a large number of different genes.
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Affiliation(s)
- Kevin J Mitchell
- Smurfit Institute of Genetics and Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.
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91
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Poza JJ. The genetics of focal epilepsies. HANDBOOK OF CLINICAL NEUROLOGY 2012; 107:153-161. [PMID: 22938969 DOI: 10.1016/b978-0-444-52898-8.00009-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Affiliation(s)
- Juan José Poza
- Department of Neurology, Hospital Donostia, San Sebastian, Spain.
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92
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Cavalleri GL, Delanty N. Opportunities and challenges for genome sequencing in the clinic. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2012; 89:65-83. [PMID: 23046882 DOI: 10.1016/b978-0-12-394287-6.00003-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Human genome sequencing technology is developing rapidly. These developments are providing exciting opportunities for genetic mapping of human traits, ranging from accelerated discovery of mutations underlying relatively simple Mendelian disorders to more genetically complex human diseases. This chapter outlines the development of whole-genome sequencing in a historical context of genetic mapping and explores the impact that sequencing is having on gene discovery study design. Using the example of epilepsy, the authors outline the opportunities and barriers for the translation of genetic predictors from discovery to the clinic. Finally, the authors discuss the practical challenges of actual implementation of whole-genome sequencing to the clinic.
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Affiliation(s)
- Gianpiero L Cavalleri
- Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland.
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93
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Alfirevic A, McCormack M, Pirmohamed M, Cavalleri G. Response 2 to pharmacogenetic screening to prevent carbamazepine-induced toxic epidermal necrolysis and Stevens-Johnson syndrome: a critical appraisal. Br J Dermatol 2011. [DOI: 10.1111/j.1365-2133.2011.10760.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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94
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Alhusaini S, Doherty CP, Scanlon C, Ronan L, Maguire S, Borgulya G, Brennan P, Delanty N, Fitzsimons M, Cavalleri GL. A cross-sectional MRI study of brain regional atrophy and clinical characteristics of temporal lobe epilepsy with hippocampal sclerosis. Epilepsy Res 2011; 99:156-66. [PMID: 22197033 DOI: 10.1016/j.eplepsyres.2011.11.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2011] [Revised: 11/09/2011] [Accepted: 11/13/2011] [Indexed: 11/29/2022]
Abstract
PURPOSE Applying a cross-sectional design, we set out to further characterize the significance of extrahippocampal brain atrophy in a large sample of 'sporadic' mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE+HS). By evaluating the influence of epilepsy chronicity on structural atrophy, this work represents an important step towards the characterization of MRI-based volumetric measurements as genetic endophenotypes for this condition. METHODS Using an automated brain segmentation technique, MRI-based volume measurements of several brain regions were compared between 75 patients with 'sporadic' MTLE+HS and 50 healthy controls. Applying linear regression models, we examined the relationship between structural atrophy and important clinical features of MTLE+HS, including disease duration, lifetime number of partial and generalized seizures, and history of initial precipitating insults (IPIs). RESULTS Significant volume loss was detected in ipsilateral hippocampus, amygdala, thalamus, and cerebral white matter (WM). In addition, contralateral hippocampal and bilateral cerebellar grey matter (GM) volume loss was observed in left MTLE+HS patients. Hippocampal, amygdalar, and cerebral WM volume loss correlated with duration of epilepsy. This correlation was stronger in patients with prior IPIs history. Further, cerebral WM, cerebellar GM, and contralateral hippocampal volume loss correlated with lifetime number of generalized seizures. CONCLUSION Our findings confirm that multiple brain regions beyond the hippocampus are involved in the pathogenesis of MTLE+HS. IPIs are an important factor influencing the rate of regional atrophy but our results also support a role for processes related to epilepsy chronicity. The consequence of epilepsy chronicity on candidate brain regions has important implications on their application as genetic endophenotypes.
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Affiliation(s)
- Saud Alhusaini
- Department of Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin 2, Ireland
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95
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Guo Y, Baum LW, Sham PC, Wong V, Ng PW, Lui CHT, Sin NC, Tsoi TH, Tang CS, Kwan JS, Yip BH, Xiao SM, Thomas GN, Lau YL, Yang W, Cherny SS, Kwan P. Two-stage genome-wide association study identifies variants in CAMSAP1L1 as susceptibility loci for epilepsy in Chinese. Hum Mol Genet 2011; 21:1184-9. [DOI: 10.1093/hmg/ddr550] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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96
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Margineanu DG. Systems biology impact on antiepileptic drug discovery. Epilepsy Res 2011; 98:104-15. [PMID: 22055355 DOI: 10.1016/j.eplepsyres.2011.10.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Revised: 09/21/2011] [Accepted: 10/06/2011] [Indexed: 01/22/2023]
Abstract
Systems biology (SB), a recent trend in bioscience research to consider the complex interactions in biological systems from a holistic perspective, sees the disease as a disturbed network of interactions, rather than alteration of single molecular component(s). SB-relying network pharmacology replaces the prevailing focus on specific drug-receptor interaction and the corollary of rational drug design of "magic bullets", by the search for multi-target drugs that would act on biological networks as "magic shotguns". Epilepsy being a multi-factorial, polygenic and dynamic pathology, SB approach appears particularly fit and promising for antiepileptic drug (AED) discovery. In fact, long before the advent of SB, AED discovery already involved some SB-like elements. A reported SB project aimed to find out new drug targets in epilepsy relies on a relational database that integrates clinical information, recordings from deep electrodes and 3D-brain imagery with histology and molecular biology data on modified expression of specific genes in the brain regions displaying spontaneous epileptic activity. Since hitting a single target does not treat complex diseases, a proper pharmacological promiscuity might impart on an AED the merit of being multi-potent. However, multi-target drug discovery entails the complicated task of optimizing multiple activities of compounds, while having to balance drug-like properties and to control unwanted effects. Specific design tools for this new approach in drug discovery barely emerge, but computational methods making reliable in silico predictions of poly-pharmacology did appear, and their progress might be quite rapid. The current move away from reductionism into network pharmacology allows expecting that a proper integration of the intrinsic complexity of epileptic pathology in AED discovery might result in literally anti-epileptic drugs.
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Affiliation(s)
- Doru Georg Margineanu
- Department of Neurosciences, Faculty of Medicine and Pharmacy, University of Mons, Ave. Champ de Mars 6, B-7000 Mons, Belgium.
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97
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Johnson MR, Shorvon SD. Heredity in epilepsy: neurodevelopment, comorbidity, and the neurological trait. Epilepsy Behav 2011; 22:421-7. [PMID: 21890419 DOI: 10.1016/j.yebeh.2011.07.031] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2011] [Accepted: 07/24/2011] [Indexed: 12/15/2022]
Abstract
The genetic bases of common, nonmendelian epilepsy have been difficult to elucidate. In this article, we argue for a new approach to genetic inquiry in epilepsy. In the latter part of the 19th century, epilepsy was universally acknowledged to be part of a wider "neurological trait" that included other neuropsychiatric conditions. In recent years, studies of comorbidity have shown clear links between epilepsy and various neuropsychiatric disorders including psychosis and depression, and genetic studies of copy number variants (CNVs) have shown that in some cases, the same CNV underpins neuropsychiatric illness and epilepsy. Functional annotation analysis of the sets of genes impacted by epilepsy CNVs shows enrichment for genes involved with neural development, with gene ontological (GO) categories including "neurological system process" (P=0.006), "synaptic transmission" (P=0.009), and "learning or memory" (P=0.01). These data support the view that epilepsy and some neuropsychiatric conditions share pathogenic neurodevelopmental pathways, and that epilepsy should be included in the spectrum of neurodevelopmental disorders. Yet, most current genetic research in epilepsy has restricted samples to specific types of epilepsy categorized according to the clinical classification schemes on the basis of seizure type, anatomical location, or epilepsy syndrome. These schemes are, to an extent, arbitrary and do not necessarily align with biological reality. We propose an alternative approach that makes no phenotypic assumptions beyond including epilepsy in the neurodevelopmental spectrum. A "'value-free" strategy of reverse phenotyping may be worth exploring, starting with genetic association and looking backward at the phenotype. Finally, it should be noted that there are societal implications to associating epilepsy with other neuropsychiatric disorders, and it is vital to ensure research in this area does not result in increased stigma for patients with epilepsy.
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Affiliation(s)
- Michael R Johnson
- Centre for Neuroscience, Imperial College London, Charing Cross Hospital, London, UK.
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98
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A genetic epidemiological survey of idiopathic epilepsy in the Chinese Han population. Epilepsy Res 2011; 98:199-205. [PMID: 21993360 DOI: 10.1016/j.eplepsyres.2011.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 09/20/2011] [Accepted: 09/20/2011] [Indexed: 11/20/2022]
Abstract
BACKGROUND Idiopathic epilepsy (IE) is a syndrome that comprises epilepsy only, with no underlying structural brain lesion or other neurological signs or symptoms. Numerous studies have shown that genetic factors play an important role in IE. IE is a common disease in the Chinese Han population. However, the genetic epidemiological characteristics of IE in the Chinese population, such as its heritability and genetic models remain unclear. PURPOSE To study the clinical and epidemiological profile of IE, to estimate the heritability and determine the possible genetic models for IE in the Chinese Han population. METHODS A case-control family-based study was carried out in a rural Chinese county. We collected data from eligible IE patients, controls, and their relatives by a uniform structured questionnaire, and then established an epidemiologic database of epilepsy using Access2010. General statistical and genetic epidemiological analyses (Falconer's-method-based heritability, simple segregation ratio and complex segregation analysis) were performed using SAS9.1 and the SAGE-SEGREG program. RESULTS (1) The prevalence of IE among the relatives of probands with IE (2.75‰) was higher than that among the relatives of the control group (0.61‰). The prevalence of IE among the first-, second-, and third-degree relatives of the probands with IE was 11.45‰, 2.64‰ and 0.98‰, respectively, which were all higher than the corresponding prevalences in the relatives of controls. Trend-chi-squared tests indicated that the prevalence of epilepsy increased among the relatives of probands with decreasing kinship distance (χ(2)=97.16, P=0.00). (2) The heritability of IE among first-, second-, and third-degree relatives was 55.06%, 50.72% and 16.98%, respectively. The weighted mean heritability was 46.07%. (3) The simple segregation ratio of IE was 0.03, significantly lower than the Mendelian recessive segregation ratio of 0.25. Complex segregation analysis showed that the population we studied accepted a Mendelian genetic model (dominant, recessive, additive, and a major gene model) and excluded the general model, non-transmitted model, and environment-only model. A Mendelian additive inheritance model was ultimately the best-fit because it had the lowest Akaike Information Criteria score. CONCLUSION In the Chinese Han population, IE follows a pattern of polygenic Mendelian additive inheritance rather than single-gene inheritance. Nearly half of the total variance can be explained by genetic factors.
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99
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Cavalleri GL, McCormack M, Alhusaini S, Chaila E, Delanty N. Pharmacogenomics and epilepsy: the road ahead. Pharmacogenomics 2011; 12:1429-47. [DOI: 10.2217/pgs.11.85] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Epilepsy is one of the most common, serious neurological disorders, affecting an estimated 50 million people worldwide. The condition is typically treated using antiepileptic drugs of which there are 16 in widespread use. However, there are many different syndrome and seizure types within epilepsy and information guiding clinicians on the most effective drug and dose for individual patients is lacking. Further, all of the antiepileptic drugs have associated adverse reactions, some of which are severe and life-threatening. Here, we review the pharmacogenomic work to date in the context of these issues and comment on key aspects of study design that are required to speed up the identification of clinically relevant genetic factors.
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Affiliation(s)
| | - Mark McCormack
- Molecular & Cellular Therapeutics, the Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Saud Alhusaini
- Molecular & Cellular Therapeutics, the Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Elijah Chaila
- The Division of Neurology, Beaumont Hospital, Dublin, Ireland
| | - Norman Delanty
- Molecular & Cellular Therapeutics, the Royal College of Surgeons in Ireland, Dublin, Ireland
- The Division of Neurology, Beaumont Hospital, Dublin, Ireland
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100
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Li L, Li Y, Browning SR, Browning BL, Slater AJ, Kong X, Aponte JL, Mooser VE, Chissoe SL, Whittaker JC, Nelson MR, Ehm MG. Performance of genotype imputation for rare variants identified in exons and flanking regions of genes. PLoS One 2011; 6:e24945. [PMID: 21949800 PMCID: PMC3176314 DOI: 10.1371/journal.pone.0024945] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Accepted: 08/24/2011] [Indexed: 12/28/2022] Open
Abstract
Genotype imputation has the potential to assess human genetic variation at a lower cost than assaying the variants using laboratory techniques. The performance of imputation for rare variants has not been comprehensively studied. We utilized 8865 human samples with high depth resequencing data for the exons and flanking regions of 202 genes and Genome-Wide Association Study (GWAS) data to characterize the performance of genotype imputation for rare variants. We evaluated reference sets ranging from 100 to 3713 subjects for imputing into samples typed for the Affymetrix (500K and 6.0) and Illumina 550K GWAS panels. The proportion of variants that could be well imputed (true r(2)>0.7) with a reference panel of 3713 individuals was: 31% (Illumina 550K) or 25% (Affymetrix 500K) with MAF (Minor Allele Frequency) less than or equal 0.001, 48% or 35% with 0.001 0.05. The performance for common SNPs (MAF>0.05) within exons and flanking regions is comparable to imputation of more uniformly distributed SNPs. The performance for rare SNPs (0.01
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Affiliation(s)
- Li Li
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - Yun Li
- Department of Genetics, Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina, United States of America
| | - Sharon R. Browning
- Department of Biostatistics, University of Washington, Seattle, Washington, United States of America
| | - Brian L. Browning
- Division of Medical Genetics, Department of Medicine, University of Washington, Seattle, Washington, United States of America
| | - Andrew J. Slater
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - Xiangyang Kong
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - Jennifer L. Aponte
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - Vincent E. Mooser
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - Stephanie L. Chissoe
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - John C. Whittaker
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - Matthew R. Nelson
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
| | - Margaret Gelder Ehm
- Genetics, GlaxoSmithKline, Research Triangle Park, North Carolina, United States of America, King of Prussia, Pennsylvania, United States of America, and Stevenage, United Kingdom
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