1
|
Hu K, Liang P. Transcriptome Analysis Reveals Higher Levels of Mobile Element-Associated Abnormal Gene Transcripts in Temporal Lobe Epilepsy Patients. Front Genet 2021; 12:767341. [PMID: 34868252 PMCID: PMC8640520 DOI: 10.3389/fgene.2021.767341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 10/25/2021] [Indexed: 11/13/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) is the most common form of epilepsy, and temporal lobe epilepsy patients with hippocampal sclerosis (TLE-HS) show worse drug treatment effects and prognosis. TLE has been shown to have a genetic component, but its genetic research has been mostly limited to coding sequences of genes with known association to epilepsy. Representing a major component of the genome, mobile elements (MEs) are believed to contribute to the genetic etiology of epilepsy despite limited research. We analyzed publicly available human RNA-seq-based transcriptome data to determine the role of mobile elements in epilepsy by performing de novo transcriptome assembly, followed by identification of spliced gene transcripts containing mobile element (ME) sequences (ME-transcripts), to compare their frequency across different sample groups. Significantly higher levels of ME-transcripts in hippocampal tissues of epileptic patients, particularly in TLE-HS, were observed. Among ME classes, short interspersed nuclear elements (SINEs) were shown to be the most frequent contributor to ME-transcripts, followed by long interspersed nuclear elements (LINEs) and DNA transposons. These ME sequences almost in all cases represent older MEs normally located in the intron sequences. For protein coding genes, ME sequences were mostly found in the 3'-UTR regions, with a significant portion also in the coding sequences (CDSs), leading to reading frame disruption. Genes associated with ME-transcripts showed enrichment for the mRNA splicing process and an apparent bias in epileptic transcriptomes toward neural- and epilepsy-associated genes. The findings of this study suggest that abnormal splicing involving MEs, leading to loss of functions in critical genes, plays a role in epilepsy, particularly in TLE-HS, thus providing a novel insight into the molecular mechanisms underlying epileptogenesis.
Collapse
Affiliation(s)
- Kai Hu
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada.,Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Ping Liang
- Department of Biological Sciences, Brock University, St. Catharines, ON, Canada
| |
Collapse
|
2
|
Koch N, Koch D, Krueger S, Tröger J, Sabanov V, Ahmed T, McMillan LE, Wolf D, Montag D, Kessels MM, Balschun D, Qualmann B. Syndapin I Loss-of-Function in Mice Leads to Schizophrenia-Like Symptoms. Cereb Cortex 2020; 30:4306-4324. [DOI: 10.1093/cercor/bhaa013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/10/2020] [Accepted: 01/14/2020] [Indexed: 12/12/2022] Open
Abstract
Abstract
Schizophrenia is associated with cognitive and behavioral dysfunctions thought to reflect imbalances in neurotransmission systems. Recent screenings suggested that lack of (functional) syndapin I (PACSIN1) may be linked to schizophrenia. We therefore studied syndapin I KO mice to address the suggested causal relationship to schizophrenia and to analyze associated molecular, cellular, and neurophysiological defects. Syndapin I knockout (KO) mice developed schizophrenia-related behaviors, such as hyperactivity, reduced anxiety, reduced response to social novelty, and an exaggerated novel object response and exhibited defects in dendritic arborization in the cortex. Neuromorphogenic deficits were also observed for a schizophrenia-associated syndapin I mutant in cultured neurons and coincided with a lack of syndapin I–mediated membrane recruitment of cytoskeletal effectors. Syndapin I KO furthermore caused glutamatergic hypofunctions. Syndapin I regulated both AMPAR and NMDAR availabilities at synapses during basal synaptic activity and during synaptic plasticity—particularly striking were a complete lack of long-term potentiation and defects in long-term depression in syndapin I KO mice. These synaptic plasticity defects coincided with alterations of postsynaptic actin dynamics, synaptic GluA1 clustering, and GluA1 mobility. Both GluA1 and GluA2 were not appropriately internalized. Summarized, syndapin I KO led to schizophrenia-like behavior, and our analyses uncovered associated molecular and cellular mechanisms.
Collapse
Affiliation(s)
- Nicole Koch
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Dennis Koch
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Sarah Krueger
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Jessica Tröger
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Victor Sabanov
- Laboratory of Biological Psychology, Brain & Cognition, University of Leuven, 3000 Leuven, Belgium
| | - Tariq Ahmed
- Laboratory of Biological Psychology, Brain & Cognition, University of Leuven, 3000 Leuven, Belgium
| | - Laura E McMillan
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - David Wolf
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Dirk Montag
- Neurogenetics Lab, Leibniz Institute for Neurobiology, 39116 Magdeburg, Germany
| | - Michael M Kessels
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| | - Detlef Balschun
- Laboratory of Biological Psychology, Brain & Cognition, University of Leuven, 3000 Leuven, Belgium
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital—Friedrich Schiller University Jena, 07743 Jena, Germany
| |
Collapse
|
3
|
Beretta S, Gritti L, Verpelli C, Sala C. Eukaryotic Elongation Factor 2 Kinase a Pharmacological Target to Regulate Protein Translation Dysfunction in Neurological Diseases. Neuroscience 2020; 445:42-49. [PMID: 32088293 DOI: 10.1016/j.neuroscience.2020.02.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 02/10/2020] [Accepted: 02/11/2020] [Indexed: 02/02/2023]
Abstract
Two major processes tightly regulate protein synthesis, the initiation of mRNA translation and elongation phase that mediates the movement of ribosomes along the mRNA. The elongation phase is a high energy-consuming process, and is mainly regulated by the eukaryotic elongation factor 2 kinase (eEF2K) activity that phosphorylates and inhibits eEF2, the only known substrate of the kinase. eEF2K activity is closely regulated by several signaling pathways because the translation elongation phase strongly influences the cellular energy demand and can change the expression of specific proteins in different tissues. An increasing number of recent findings link eEF2k over activation to an array of human diseases, such as atherosclerosis, pulmonary arterial hypertension, progression of solid tumors, and some major neurological disorders. Several neurological studies suggest that eEF2K is a valuable target in treating epilepsy, depression and major neurodegenerative diseases. Despite eEF2k is an ubiquitous and conserved protein, it has been proved that its deletion does not affect development in animal models and in general cell viability. Therefore, it is possible to postulate that inhibiting its function may not cause serious side effects. In addition, eEF2K is a peculiar kinase molecularly different from most of other mammalian kinases and new compounds that inhibit eEF2K should not necessarily interfere with other important protein kinases. In this review we will critically summarize the evidence supporting the role of the altered eEF2K/eEF2 pathway in defined neurological diseases and its implications in curing these diseases in animal models, and possibly in humans, by targeting eEF2K activity.
Collapse
Affiliation(s)
| | | | | | - Carlo Sala
- CNR Neuroscience Institute, Milano, Italy.
| |
Collapse
|
4
|
Protein mutated in paroxysmal dyskinesia interacts with the active zone protein RIM and suppresses synaptic vesicle exocytosis. Proc Natl Acad Sci U S A 2015; 112:2935-41. [PMID: 25730884 DOI: 10.1073/pnas.1501364112] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Paroxysmal nonkinesigenic dyskinesia (PNKD) is an autosomal dominant episodic movement disorder precipitated by coffee, alcohol, and stress. We previously identified the causative gene but the function of the encoded protein remains unknown. We also generated a PNKD mouse model that revealed dysregulated dopamine signaling in vivo. Here, we show that PNKD interacts with synaptic active zone proteins Rab3-interacting molecule (RIM)1 and RIM2, localizes to synapses, and modulates neurotransmitter release. Overexpressed PNKD protein suppresses release, and mutant PNKD protein is less effective than wild-type at inhibiting exocytosis. In PNKD KO mice, RIM1/2 protein levels are reduced and synaptic strength is impaired. Thus, PNKD is a novel synaptic protein with a regulatory role in neurotransmitter release.
Collapse
|
5
|
Ekenstedt KJ, Oberbauer AM. Inherited epilepsy in dogs. Top Companion Anim Med 2014; 28:51-8. [PMID: 24070682 DOI: 10.1053/j.tcam.2013.07.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 07/01/2013] [Indexed: 12/15/2022]
Abstract
Epilepsy is the most common neurologic disease in dogs and many forms are considered to have a genetic basis. In contrast, some seizure disorders are also heritable, but are not technically defined as epilepsy. Investigation of true canine epilepsies has uncovered genetic associations in some cases, however, many remain unexplained. Gene mutations have been described for 2 forms of canine epilepsy: primary epilepsy (PE) and progressive myoclonic epilepsies. To date, 9 genes have been described to underlie progressive myoclonic epilepsies in several dog breeds. Investigations into genetic PE have been less successful, with only 1 causative gene described. Genetic testing as an aid to diagnosis, prognosis, and breeding decisions is available for these 10 forms. Additional studies utilizing genome-wide tools have identified PE loci of interest; however, specific genetic tests are not yet developed. Many studies of dog breeds with PE have failed to identify genes or loci of interest, suggesting that, similar to what is seen in many human genetic epilepsies, inheritance is likely complex, involving several or many genes, and reflective of environmental interactions. An individual dog's response to therapeutic intervention for epilepsy may also be genetically complex. Although the field of inherited epilepsy has faced challenges, particularly with PE, newer technologies contribute to further advances.
Collapse
Affiliation(s)
- Kari J Ekenstedt
- Department of Animal and Food Science, College of Agriculture, Food, and Environmental Sciences, University of Wisconsin - River Falls, River Falls, WI, USA.
| | | |
Collapse
|
6
|
Münch A, Dibué M, Hescheler J, Schneider T. Cav2.3 E-/R-type voltage-gated calcium channels modulate sleep in mice. SOMNOLOGIE 2013. [DOI: 10.1007/s11818-013-0628-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
7
|
Soini HK, Moilanen JS, Vilmi-Kerälä T, Finnilä S, Majamaa K. Mitochondrial DNA variant m.15218A > G in Finnish epilepsy patients who have maternal relatives with epilepsy, sensorineural hearing impairment or diabetes mellitus. BMC MEDICAL GENETICS 2013; 14:73. [PMID: 23870133 PMCID: PMC3726289 DOI: 10.1186/1471-2350-14-73] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 07/17/2013] [Indexed: 01/04/2023]
Abstract
BACKGROUND Mitochondrial diseases caused by mutations in mitochondrial DNA (mtDNA) affect tissues with high energy demand. Epilepsy is one of the manifestations of mitochondrial dysfunction when the brain is affected. We have studied here 79 Finnish patients with epilepsy and who have maternal first- or second-degree relatives with epilepsy, sensorineural hearing impairment or diabetes mellitus. METHODS The entire mtDNA was studied by using conformation sensitive gel electrophoresis and PCR fragments that differed in mobility were directly sequenced. RESULTS We found a common nonsynonymous variant m.15218A > G (p.T158A, MTCYB) that occurs in haplogroup U5a1 to be more frequent in patients with epilepsy. The m.15218A > G variant was present in five patients with epilepsy and in four out of 403 population controls (p = 0.0077). This variant was present in two branches in the phylogenetic network constructed on the basis of mtDNA variation among the patients. Three algorithms predicted that m.15218A > G is damaging in effect. CONCLUSIONS We suggest that the m.15218A > G variant is mildly deleterious and that mtDNA involvement should be considered in patients with epilepsy and who have a maternal history of epilepsy, sensorineural hearing impairment or diabetes mellitus.
Collapse
Affiliation(s)
- Heidi K Soini
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Jukka S Moilanen
- Department of Clinical Genetics, Oulu University Hospital and University of Oulu P.O. Box 23, FI-90029, OYS, Oulu, Finland
| | - Tiina Vilmi-Kerälä
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Saara Finnilä
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
| | - Kari Majamaa
- Department of Neurology, Oulu University Hospital, P.O. Box 20, Oulu FI-90029, OYS, Finland
- Department of Clinical Medicine, Neurology, University of Oulu, P.O. Box 5000, FI-90014, Oulu, Finland
- Clinical Research Center, Oulu University Hospital, P.O. Box 5000, FI-90014, Oulu, Finland
| |
Collapse
|
8
|
Giannandrea M, Guarnieri FC, Gehring NH, Monzani E, Benfenati F, Kulozik AE, Valtorta F. Nonsense-mediated mRNA decay and loss-of-function of the protein underlie the X-linked epilepsy associated with the W356× mutation in synapsin I. PLoS One 2013; 8:e67724. [PMID: 23818987 PMCID: PMC3688603 DOI: 10.1371/journal.pone.0067724] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 05/21/2013] [Indexed: 11/22/2022] Open
Abstract
Synapsins are a family of neuronal phosphoproteins associated with the cytosolic surface of synaptic vesicles. Experimental evidence suggests a role for synapsins in synaptic vesicle clustering and recycling at the presynaptic terminal, as well as in neuronal development and synaptogenesis. Synapsin knock-out (Syn1(-/-) ) mice display an epileptic phenotype and mutations in the SYN1 gene have been identified in individuals affected by epilepsy and/or autism spectrum disorder. We investigated the impact of the c.1067G>A nonsense transition, the first mutation described in a family affected by X-linked syndromic epilepsy, on the expression and functional properties of the synapsin I protein. We found that the presence of a premature termination codon in the human SYN1 transcript renders it susceptible to nonsense-mediated mRNA decay (NMD). Given that the NMD efficiency is highly variable among individuals and cell types, we investigated also the effects of expression of the mutant protein and found that it is expressed at lower levels compared to wild-type synapsin I, forms perinuclear aggregates and is unable to reach presynaptic terminals in mature hippocampal neurons grown in culture. Taken together, these data indicate that in patients carrying the W356× mutation the function of synapsin I is markedly impaired, due to both the strongly decreased translation and the altered function of the NMD-escaped protein, and support the value of Syn1(-/-) mice as an experimental model mimicking the human pathology.
Collapse
MESH Headings
- Animals
- Blotting, Northern
- Cells, Cultured
- Codon, Nonsense
- Epilepsy/genetics
- Epilepsy/metabolism
- Female
- Gene Expression
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/metabolism
- HeLa Cells
- Hippocampus/cytology
- Hippocampus/metabolism
- Humans
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Fluorescence
- Microtubule-Associated Proteins/metabolism
- Neurons/metabolism
- Nonsense Mediated mRNA Decay
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Synapsins/genetics
- Synapsins/metabolism
Collapse
Affiliation(s)
- Maila Giannandrea
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | - Fabrizia C. Guarnieri
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | | | - Elena Monzani
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| | - Fabio Benfenati
- Department of Neuroscience and Brain Technologies, The Italian Institute of Technology, Genoa, Italy
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Andreas E. Kulozik
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg Medical Center and Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany
| | - Flavia Valtorta
- Division of Neuroscience, San Raffaele Scientific Institute and Vita-Salute University, Milan, Italy
| |
Collapse
|
9
|
Casillas-Espinosa PM, Powell KL, O'Brien TJ. Regulators of synaptic transmission: roles in the pathogenesis and treatment of epilepsy. Epilepsia 2013; 53 Suppl 9:41-58. [PMID: 23216578 DOI: 10.1111/epi.12034] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Synaptic transmission is the communication between a presynaptic and a postsynaptic neuron, and the subsequent processing of the signal. These processes are complex and highly regulated, reflecting their importance in normal brain functioning and homeostasis. Sustaining synaptic transmission depends on the continuing cycle of synaptic vesicle formation, release, and endocytosis, which requires proteins such as dynamin, syndapin, synapsin, and synaptic vesicle protein 2A. Synaptic transmission is regulated by diverse mechanisms, including presynaptic modulators of synaptic vesicle formation and release, postsynaptic receptors and signaling, and modulators of neurotransmission. Neurotransmitters released presynaptically can bind to their postsynaptic receptors, the inhibitory γ-aminobutyric acid (GABA)ergic receptors or the excitatory glutamate receptors. Once released, glutamate activates a variety of postsynaptic receptors including α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA), N-methyl-D-aspartate (NMDA), kainate, and metabotropic receptors. The activation of the receptors triggers downstream signaling cascades generating a vast array of effects, which can be modulated by a numerous auxiliary regulatory subunits. Moreover, different neuropeptides such as neuropeptide Y, brain-derived neurotrophic factor (BDNF), somatostatin, ghrelin, and galanin, act as regulators of diverse synaptic functions and along with the classic neurotransmitters. Abnormalities in the regulation of synaptic transmission play a critical role in the pathogenesis of numerous brain diseases, including epilepsy. This review focuses on the different mechanisms involved in the regulation of synaptic transmission, which may play a role in the pathogenesis of epilepsy: the presynaptic modulators of synaptic vesicle formation and release, postsynaptic receptors, and modulators of neurotransmission, including the mechanism by which drugs can modulate the frequency and severity of epileptic seizures.
Collapse
Affiliation(s)
- Pablo M Casillas-Espinosa
- The Departments of Medicine and Neurology, The Royal Melbourne Hospital, The Melbourne Brain Centre, The University of Melbourne, Parkville, Victoria, Australia
| | | | | |
Collapse
|
10
|
Bartnik M, Szczepanik E, Derwińska K, Wiśniowiecka-Kowalnik B, Gambin T, Sykulski M, Ziemkiewicz K, Kędzior M, Gos M, Hoffman-Zacharska D, Mazurczak T, Jeziorek A, Antczak-Marach D, Rudzka-Dybała M, Mazurkiewicz H, Goszczańska-Ciuchta A, Zalewska-Miszkurka Z, Terczyńska I, Sobierajewicz M, Shaw CA, Gambin A, Mierzewska H, Mazurczak T, Obersztyn E, Bocian E, Stankiewicz P. Application of array comparative genomic hybridization in 102 patients with epilepsy and additional neurodevelopmental disorders. Am J Med Genet B Neuropsychiatr Genet 2012; 159B:760-71. [PMID: 22825934 DOI: 10.1002/ajmg.b.32081] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2012] [Accepted: 07/02/2012] [Indexed: 01/19/2023]
Abstract
Copy-number variants (CNVs) collectively represent an important cause of neurodevelopmental disorders such as developmental delay (DD)/intellectual disability (ID), autism, and epilepsy. In contrast to DD/ID, for which the application of microarray techniques enables detection of pathogenic CNVs in -10-20% of patients, there are only few studies of the role of CNVs in epilepsy and genetic etiology in the vast majority of cases remains unknown. We have applied whole-genome exon-targeted oligonucleotide array comparative genomic hybridization (array CGH) to a cohort of 102 patients with various types of epilepsy with or without additional neurodevelopmental abnormalities. Chromosomal microarray analysis revealed 24 non-polymorphic CNVs in 23 patients, among which 10 CNVs are known to be clinically relevant. Two rare deletions in 2q24.1q24.3, including KCNJ3 and 9q21.13 are novel pathogenic genetic loci and 12 CNVs are of unknown clinical significance. Our results further support the notion that rare CNVs can cause different types of epilepsy, emphasize the efficiency of detecting novel candidate genes by whole-genome array CGH, and suggest that the clinical application of array CGH should be extended to patients with unexplained epilepsies.
Collapse
Affiliation(s)
- Magdalena Bartnik
- Department of Medical Genetics, Institute of Mother and Child, Warsaw, Poland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Ashrafian H. Familial epilepsy in the pharaohs of ancient Egypt's eighteenth dynasty. Epilepsy Behav 2012; 25:23-31. [PMID: 22980077 DOI: 10.1016/j.yebeh.2012.06.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 06/06/2012] [Accepted: 06/09/2012] [Indexed: 11/16/2022]
Abstract
The pharaohs of Egypt's famous eighteenth dynasty all died early of unknown causes. This paper comprehensively reviews and analyses the medical literature and current evidence available for the New Kingdom rulers - Tuthmosis IV, Amenhotep III, Akhenaten, Smenkhkare and Tutankhamun. The integration of these sources reveals that the eighteenth dynasty rulers may have suffered from an inherited condition that may explain their untimely deaths. The description of recurring strong religious visions, likely neurological disease and gynecomastia, supports the theory that these pharaohs may have suffered from a familial temporal epilepsy syndrome that ultimately led to their early downfall.
Collapse
Affiliation(s)
- Hutan Ashrafian
- Department of Surgery and Cancer, Imperial College London at St. Mary's Hospital Campus, London, UK.
| |
Collapse
|
12
|
Seppälä EH, Koskinen LLE, Gulløv CH, Jokinen P, Karlskov-Mortensen P, Bergamasco L, Baranowska Körberg I, Cizinauskas S, Oberbauer AM, Berendt M, Fredholm M, Lohi H. Identification of a novel idiopathic epilepsy locus in Belgian Shepherd dogs. PLoS One 2012; 7:e33549. [PMID: 22457775 PMCID: PMC3311644 DOI: 10.1371/journal.pone.0033549] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2011] [Accepted: 02/11/2012] [Indexed: 01/19/2023] Open
Abstract
Epilepsy is the most common neurological disorder in dogs, with an incidence ranging from 0.5% to up to 20% in particular breeds. Canine epilepsy can be etiologically defined as idiopathic or symptomatic. Epileptic seizures may be classified as focal with or without secondary generalization, or as primary generalized. Nine genes have been identified for symptomatic (storage diseases) and one for idiopathic epilepsy in different breeds. However, the genetic background of common canine epilepsies remains unknown. We have studied the clinical and genetic background of epilepsy in Belgian Shepherds. We collected 159 cases and 148 controls and confirmed the presence of epilepsy through epilepsy questionnaires and clinical examinations. The MRI was normal while interictal EEG revealed abnormalities and variable foci in the clinically examined affected dogs. A genome-wide association study using Affymetrix 50K SNP arrays in 40 cases and 44 controls mapped the epilepsy locus on CFA37, which was replicated in an independent cohort (81 cases and 88 controls; combined p = 9.70×10−10, OR = 3.3). Fine mapping study defined a ∼1 Mb region including 12 genes of which none are known epilepsy genes or encode ion channels. Exonic sequencing was performed for two candidate genes, KLF7 and ADAM23. No variation was found in KLF7 but a highly-associated non-synonymous variant, G1203A (R387H) was present in the ADAM23 gene (p = 3.7×10−8, OR = 3.9 for homozygosity). Homozygosity for a two-SNP haplotype within the ADAM23 gene conferred the highest risk for epilepsy (p = 6.28×10−11, OR = 7.4). ADAM23 interacts with known epilepsy proteins LGI1 and LGI2. However, our data suggests that the ADAM23 variant is a polymorphism and we have initiated a targeted re-sequencing study across the locus to identify the causative mutation. It would establish the affected breed as a novel therapeutic model, help to develop a DNA test for breeding purposes and introduce a novel candidate gene for human idiopathic epilepsies.
Collapse
Affiliation(s)
- Eija H. Seppälä
- Research Programs Unit, Molecular Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences and Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Lotta L. E. Koskinen
- Research Programs Unit, Molecular Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences and Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Christina H. Gulløv
- Department of Small Animal Clinical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Päivi Jokinen
- Research Programs Unit, Molecular Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences and Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Peter Karlskov-Mortensen
- Department of Basic Animal and Veterinary Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Luciana Bergamasco
- College of Veterinary Medicine, Kansas State University, Manhattan, Kansas, United States of America
| | | | | | - Anita M. Oberbauer
- Department of Animal Science, University of California Davis, Davis, California, United States of America
| | - Mette Berendt
- Department of Small Animal Clinical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Merete Fredholm
- Department of Basic Animal and Veterinary Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hannes Lohi
- Research Programs Unit, Molecular Medicine, University of Helsinki, Helsinki, Finland
- Department of Veterinary Biosciences and Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Folkhälsan Institute of Genetics, Helsinki, Finland
- * E-mail:
| |
Collapse
|
13
|
Voltage-Gated Ca2+ Channel Mediated Ca2+ Influx in Epileptogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:1219-47. [DOI: 10.1007/978-94-007-2888-2_55] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
|
14
|
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.
Collapse
Affiliation(s)
- Gianpiero L Cavalleri
- Molecular and Cellular Therapeutics, The Royal College of Surgeons in Ireland, Dublin, Ireland.
| | | |
Collapse
|
15
|
|
16
|
Koch D, Spiwoks-Becker I, Sabanov V, Sinning A, Dugladze T, Stellmacher A, Ahuja R, Grimm J, Schüler S, Müller A, Angenstein F, Ahmed T, Diesler A, Moser M, Tom Dieck S, Spessert R, Boeckers TM, Fässler R, Hübner CA, Balschun D, Gloveli T, Kessels MM, Qualmann B. Proper synaptic vesicle formation and neuronal network activity critically rely on syndapin I. EMBO J 2011; 30:4955-69. [PMID: 21926968 DOI: 10.1038/emboj.2011.339] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Accepted: 08/23/2011] [Indexed: 02/03/2023] Open
Abstract
Synaptic transmission relies on effective and accurate compensatory endocytosis. F-BAR proteins may serve as membrane curvature sensors and/or inducers and thereby support membrane remodelling processes; yet, their in vivo functions urgently await disclosure. We demonstrate that the F-BAR protein syndapin I is crucial for proper brain function. Syndapin I knockout (KO) mice suffer from seizures, a phenotype consistent with excessive hippocampal network activity. Loss of syndapin I causes defects in presynaptic membrane trafficking processes, which are especially evident under high-capacity retrieval conditions, accumulation of endocytic intermediates, loss of synaptic vesicle (SV) size control, impaired activity-dependent SV retrieval and defective synaptic activity. Detailed molecular analyses demonstrate that syndapin I plays an important role in the recruitment of all dynamin isoforms, central players in vesicle fission reactions, to the membrane. Consistently, syndapin I KO mice share phenotypes with dynamin I KO mice, whereas their seizure phenotype is very reminiscent of fitful mice expressing a mutant dynamin. Thus, syndapin I acts as pivotal membrane anchoring factor for dynamins during regeneration of SVs.
Collapse
Affiliation(s)
- Dennis Koch
- Institute of Biochemistry I, Jena University Hospital-Friedrich Schiller University Jena, Jena, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Qualmann B, Koch D, Kessels MM. Let's go bananas: revisiting the endocytic BAR code. EMBO J 2011; 30:3501-15. [PMID: 21878992 DOI: 10.1038/emboj.2011.266] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 07/15/2011] [Indexed: 12/27/2022] Open
Abstract
Against the odds of membrane resistance, members of the BIN/Amphiphysin/Rvs (BAR) domain superfamily shape membranes and their activity is indispensable for a plethora of life functions. While crystal structures of different BAR dimers advanced our understanding of membrane shaping by scaffolding and hydrophobic insertion mechanisms considerably, especially life-imaging techniques and loss-of-function studies of clathrin-mediated endocytosis with its gradually increasing curvature show that the initial idea that solely BAR domain curvatures determine their functions is oversimplified. Diagonal placing, lateral lipid-binding modes, additional lipid-binding modules, tilde shapes and formation of macromolecular lattices with different modes of organisation and arrangement increase versatility. A picture emerges, in which BAR domain proteins create macromolecular platforms, that recruit and connect different binding partners and ensure the connection and coordination of the different events during the endocytic process, such as membrane invagination, coat formation, actin nucleation, vesicle size control, fission, detachment and uncoating, in time and space, and may thereby offer mechanistic explanations for how coordination, directionality and effectiveness of a complex process with several steps and key players can be achieved.
Collapse
Affiliation(s)
- Britta Qualmann
- Institute for Biochemistry I, University Hospital Jena-Friedrich Schiller University Jena, Germany.
| | | | | |
Collapse
|
18
|
Seppälä EH, Jokinen TS, Fukata M, Fukata Y, Webster MT, Karlsson EK, Kilpinen SK, Steffen F, Dietschi E, Leeb T, Eklund R, Zhao X, Rilstone JJ, Lindblad-Toh K, Minassian BA, Lohi H. LGI2 truncation causes a remitting focal epilepsy in dogs. PLoS Genet 2011; 7:e1002194. [PMID: 21829378 PMCID: PMC3145619 DOI: 10.1371/journal.pgen.1002194] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Accepted: 06/05/2011] [Indexed: 12/17/2022] Open
Abstract
One quadrillion synapses are laid in the first two years of postnatal construction of the human brain, which are then pruned until age 10 to 500 trillion synapses composing the final network. Genetic epilepsies are the most common neurological diseases with onset during pruning, affecting 0.5% of 2–10-year-old children, and these epilepsies are often characterized by spontaneous remission. We previously described a remitting epilepsy in the Lagotto romagnolo canine breed. Here, we identify the gene defect and affected neurochemical pathway. We reconstructed a large Lagotto pedigree of around 34 affected animals. Using genome-wide association in 11 discordant sib-pairs from this pedigree, we mapped the disease locus to a 1.7 Mb region of homozygosity in chromosome 3 where we identified a protein-truncating mutation in the Lgi2 gene, a homologue of the human epilepsy gene LGI1. We show that LGI2, like LGI1, is neuronally secreted and acts on metalloproteinase-lacking members of the ADAM family of neuronal receptors, which function in synapse remodeling, and that LGI2 truncation, like LGI1 truncations, prevents secretion and ADAM interaction. The resulting epilepsy onsets at around seven weeks (equivalent to human two years), and remits by four months (human eight years), versus onset after age eight in the majority of human patients with LGI1 mutations. Finally, we show that Lgi2 is expressed highly in the immediate post-natal period until halfway through pruning, unlike Lgi1, which is expressed in the latter part of pruning and beyond. LGI2 acts at least in part through the same ADAM receptors as LGI1, but earlier, ensuring electrical stability (absence of epilepsy) during pruning years, preceding this same function performed by LGI1 in later years. LGI2 should be considered a candidate gene for common remitting childhood epilepsies, and LGI2-to-LGI1 transition for mechanisms of childhood epilepsy remission. Major remodeling of the neuronal synaptic network occurs during childhood. The quadrillion synapses formed till the end of age two are trimmed to 500 trillion by age 10 through a selective process of strengthening of ideal connections, removal of redundant ones, and formation of new contacts. Very little is known about the basic mechanisms that direct this massive reorganization that leads to the adult brain. The most common epilepsies of humans occur in childhood and are characterized by remission prior to adulthood. Not much is known about their genetics and basic remission mechanisms. We describe here a canine equivalent disease and identify the defective gene, Lgi2. We show that the gene product is a secreted protein and interacts with neuronal ADAM receptors known to be involved in the regulation of synaptic remodeling in the developing brain. Our work sheds important light on the basic mechanisms of the most common neurological disease of children and discloses processes of epilepsy remission. The identification of the first focal epilepsy gene in dogs has also enabled the development of a genetic test to identify carriers for breeding purposes.
Collapse
Affiliation(s)
- Eija H. Seppälä
- Department of Veterinary Biosciences, Department of Medical Genetics, Research Programs Unit, Molecular Medicine, University of Helsinki, Helsinki, Finland
- Department of Molecular Genetics, Folkhälsan Research Center, Helsinki, Finland
| | - Tarja S. Jokinen
- Department of Clinical Veterinary Sciences, University of Helsinki, Helsinki, Finland
| | - Masaki Fukata
- Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences and National Institutes of Natural Sciences, Okazaki, Japan
| | - Yuko Fukata
- Division of Membrane Physiology, Department of Cell Physiology, National Institute for Physiological Sciences and National Institutes of Natural Sciences, Okazaki, Japan
- PRESTO, Japan Science and Technology Agency, Tokyo, Japan
| | - Matthew T. Webster
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
| | - Elinor K. Karlsson
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
- FAS Center for Systems Biology, Harvard University, Cambridge, Massachusetts, United States of America
| | - Sami K. Kilpinen
- Institute for Molecular Medicine Finland (FIMM), University of Helsinki, Helsinki, Finland
| | - Frank Steffen
- Department for Small Animals, Neurology Services, University of Zurich, Zurich, Switzerland
| | - Elisabeth Dietschi
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
- Department of Clinical Veterinary Medicine, Division of Small Animal Orthopedics and Surgery, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Tosso Leeb
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Ranja Eklund
- Department of Veterinary Biosciences, Department of Medical Genetics, Research Programs Unit, Molecular Medicine, University of Helsinki, Helsinki, Finland
- Department of Molecular Genetics, Folkhälsan Research Center, Helsinki, Finland
| | - Xiaochu Zhao
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Jennifer J. Rilstone
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
| | - Kerstin Lindblad-Toh
- Science for Life Laboratory, Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden
- Broad Institute of Harvard and MIT, Cambridge, Massachusetts, United States of America
| | - Berge A. Minassian
- Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Canada
- Division of Neurology, Department of Paediatrics, The Hospital for Sick Children, Toronto, Canada
| | - Hannes Lohi
- Department of Veterinary Biosciences, Department of Medical Genetics, Research Programs Unit, Molecular Medicine, University of Helsinki, Helsinki, Finland
- Department of Molecular Genetics, Folkhälsan Research Center, Helsinki, Finland
- * E-mail:
| |
Collapse
|
19
|
Lachance-Touchette P, Brown P, Meloche C, Kinirons P, Lapointe L, Lacasse H, Lortie A, Carmant L, Bedford F, Bowie D, Cossette P. Novel α1 and γ2 GABAA receptor subunit mutations in families with idiopathic generalized epilepsy. Eur J Neurosci 2011; 34:237-49. [PMID: 21714819 DOI: 10.1111/j.1460-9568.2011.07767.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Epilepsy is a heterogeneous neurological disease affecting approximately 50 million people worldwide. Genetic factors play an important role in both the onset and severity of the condition, with mutations in several ion-channel genes being implicated, including those encoding the GABA(A) receptor. Here, we evaluated the frequency of additional mutations in the GABA(A) receptor by direct sequencing of the complete open reading frame of the GABRA1 and GABRG2 genes from a cohort of French Canadian families with idiopathic generalized epilepsy (IGE). Using this approach, we have identified three novel mutations that were absent in over 400 control chromosomes. In GABRA1, two mutations were found, with the first being a 25-bp insertion that was associated with intron retention (i.e. K353delins18X) and the second corresponding to a single point mutation that replaced the aspartate 219 residue with an asparagine (i.e. D219N). Electrophysiological analysis revealed that K353delins18X and D219N altered GABA(A) receptor function by reducing the total surface expression of mature protein and/or by curtailing neurotransmitter effectiveness. Both defects would be expected to have a detrimental effect on inhibitory control of neuronal circuits. In contrast, the single point mutation identified in the GABRG2 gene, namely P83S, was indistinguishable from the wildtype subunit in terms of surface expression and functionality. This finding was all the more intriguing as the mutation exhibited a high degree of penetrance in three generations of one French Canadian family. Further experimentation will be required to understand how this mutation contributes to the occurrence of IGE in these individuals.
Collapse
Affiliation(s)
- Pamela Lachance-Touchette
- Centre for Excellence in Neuromics of University of Montreal, CHUM Research Center, 1560 Sherbrooke est, Montreal, QC, Canada H2L 4M1
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Ekenstedt KJ, Patterson EE, Minor KM, Mickelson JR. Candidate genes for idiopathic epilepsy in four dog breeds. BMC Genet 2011; 12:38. [PMID: 21518446 PMCID: PMC3111397 DOI: 10.1186/1471-2156-12-38] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Accepted: 04/25/2011] [Indexed: 01/27/2023] Open
Abstract
Background Idiopathic epilepsy (IE) is a naturally occurring and significant seizure disorder affecting all dog breeds. Because dog breeds are genetically isolated populations, it is possible that IE is attributable to common founders and is genetically homogenous within breeds. In humans, a number of mutations, the majority of which are genes encoding ion channels, neurotransmitters, or their regulatory subunits, have been discovered to cause rare, specific types of IE. It was hypothesized that there are simple genetic bases for IE in some purebred dog breeds, specifically in Vizslas, English Springer Spaniels (ESS), Greater Swiss Mountain Dogs (GSMD), and Beagles, and that the gene(s) responsible may, in some cases, be the same as those already discovered in humans. Results Candidate genes known to be involved in human epilepsy, along with selected additional genes in the same gene families that are involved in murine epilepsy or are expressed in neural tissue, were examined in populations of affected and unaffected dogs. Microsatellite markers in close proximity to each candidate gene were genotyped and subjected to two-point linkage in Vizslas, and association analysis in ESS, GSMD and Beagles. Conclusions Most of these candidate genes were not significantly associated with IE in these four dog breeds, while a few genes remained inconclusive. Other genes not included in this study may still be causing monogenic IE in these breeds or, like many cases of human IE, the disease in dogs may be likewise polygenic.
Collapse
Affiliation(s)
- Kari J Ekenstedt
- Department of Veterinary Clinical Sciences, College of Veterinary Medicine, University of Minnesota, 1352 Boyd Avenue, Saint Paul, Minnesota 55108, USA.
| | | | | | | |
Collapse
|
21
|
Voltage-gated potassium channel KCNV2 (Kv8.2) contributes to epilepsy susceptibility. Proc Natl Acad Sci U S A 2011; 108:5443-8. [PMID: 21402906 DOI: 10.1073/pnas.1017539108] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Mutations in voltage-gated ion channels are responsible for several types of epilepsy. Genetic epilepsies often exhibit variable severity in individuals with the same mutation, which may be due to variation in genetic modifiers. The Scn2a(Q54) transgenic mouse model has a sodium channel mutation and exhibits epilepsy with strain-dependent severity. We previously mapped modifier loci that influence Scn2a(Q54) phenotype severity and identified Kcnv2, encoding the voltage-gated potassium channel subunit Kv8.2, as a candidate modifier. In this study, we demonstrate a threefold increase in hippocampal Kcnv2 expression associated with more severe epilepsy. In vivo exacerbation of the phenotype by Kcnv2 transgenes supports its identification as an epilepsy modifier. The contribution of KCNV2 to human epilepsy susceptibility is supported by identification of two nonsynonymous variants in epilepsy patients that alter function of Kv2.1/Kv8.2 heterotetrameric potassium channels. Our results demonstrate that altered potassium subunit function influences epilepsy susceptibility and implicate Kcnv2 as an epilepsy gene.
Collapse
|
22
|
|
23
|
Hammond CL, Thomas RH, Rees MI, Kerr MP, Rapport F. Implications for families of advances in understanding the genetic basis of epilepsy. Seizure 2010; 19:675-9. [DOI: 10.1016/j.seizure.2010.10.022] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
|
24
|
Cossette P, Rouleau GA. Mutated GABAA receptor subunits in idiopathic generalized epilepsy. Epilepsia 2010. [DOI: 10.1111/j.1528-1167.2010.02848.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]
|
25
|
Falace A, Filipello F, La Padula V, Vanni N, Madia F, De Pietri Tonelli D, de Falco FA, Striano P, Dagna Bricarelli F, Minetti C, Benfenati F, Fassio A, Zara F. TBC1D24, an ARF6-interacting protein, is mutated in familial infantile myoclonic epilepsy. Am J Hum Genet 2010; 87:365-70. [PMID: 20727515 DOI: 10.1016/j.ajhg.2010.07.020] [Citation(s) in RCA: 116] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2010] [Revised: 07/19/2010] [Accepted: 07/22/2010] [Indexed: 12/28/2022] Open
Abstract
Idiopathic epilepsies (IEs) are a group of disorders characterized by recurrent seizures in the absence of detectable brain lesions or metabolic abnormalities. IEs include common disorders with a complex mode of inheritance and rare Mendelian traits suggesting the occurrence of several alleles with variable penetrance. We previously described a large family with a recessive form of idiopathic epilepsy, named familial infantile myoclonic epilepsy (FIME), and mapped the disease locus on chromosome 16p13.3 by linkage analysis. In the present study, we found that two compound heterozygous missense mutations (D147H and A509V) in TBC1D24, a gene of unknown function, are responsible for FIME. In situ hybridization analysis revealed that Tbc1d24 is mainly expressed at the level of the cerebral cortex and the hippocampus. By coimmunoprecipitation assay we found that TBC1D24 binds ARF6, a Ras-related family of small GTPases regulating exo-endocytosis dynamics. The main recognized function of ARF6 in the nervous system is the regulation of dendritic branching, spine formation, and axonal extension. TBC1D24 overexpression resulted in a significant increase in neurite length and arborization and the FIME mutations significantly reverted this phenotype. In this study we identified a gene mutation involved in autosomal-recessive idiopathic epilepsy, unveiled the involvement of ARF6-dependent molecular pathway in brain hyperexcitability and seizures, and confirmed the emerging role of subtle cytoarchitectural alterations in the etiology of this group of common epileptic disorders.
Collapse
Affiliation(s)
- Antonio Falace
- Department of Neuroscience, Institute G. Gaslini and University of Genova, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
26
|
Affiliation(s)
- Patrick Cossette
- Department of Medicine, Neurology Division, Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada.
| |
Collapse
|
27
|
|
28
|
Layouni S, Chouchane L, Malafosse A, Dogui M. Dimorphism of TAP-1 gene in Caucasian with juvenile myoclonic epilepsy and in Tunisian with idiopathic generalized epilepsies. Int J Immunogenet 2010; 37:117-23. [PMID: 20141545 DOI: 10.1111/j.1744-313x.2010.00900.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Juvenile myoclonic epilepsy (JME) is the most common form of idiopathic generalized epilepsies (IGE) that account for about 5-10% of all types of epilepsies. The first putative locus termed EJM1 is on the human leucocyte antigen (HLA-II) region of chromosome 6p21.3. Interestingly, the EJM1 region includes the Transporter associated with antigen processing 1 (TAP-1) gene encoding the TAP-1, and previous studies have reported associations between HLA-II polymorphisms and different types of epilepsy. In this study, we report an association between two TAP-1 functional polymorphisms the I333V and the D637G and most common IGE in Tunisian population, but we fail to find significant results in Caucasian with JME.
Collapse
Affiliation(s)
- S Layouni
- Department of Physiology, Faculty of Medicine, Monastir, Tunisia.
| | | | | | | |
Collapse
|
29
|
Zamponi GW, Lory P, Perez-Reyes E. Role of voltage-gated calcium channels in epilepsy. Pflugers Arch 2009; 460:395-403. [PMID: 20091047 DOI: 10.1007/s00424-009-0772-x] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 11/30/2009] [Accepted: 12/01/2009] [Indexed: 11/30/2022]
Abstract
It is well established that idiopathic generalized epilepsies (IGEs) show a polygenic origin and may arise from dysfunction of various types of voltage- and ligand-gated ion channels. There is an increasing body of literature implicating both high- and low-voltage-activated (HVA and LVA) calcium channels and their ancillary subunits in IGEs. Cav2.1 (P/Q-type) calcium channels control synaptic transmission at presynaptic nerve terminals, and mutations in the gene encoding the Cav2.1 alpha1 subunit (CACNA1A) have been linked to absence seizures in both humans and rodents. Similarly, mutations and loss of function mutations in ancillary HVA calcium channel subunits known to co-assemble with Cav2.1 result in IGE phenotypes in mice. It is important to note that in all these mouse models with mutations in HVA subunits, there is a compensatory increase in thalamic LVA currents which likely leads to the seizure phenotype. In fact, gain-of-function mutations have been identified in Cav3.2 (an LVA or T-type calcium channel encoded by the CACNA1H gene) in patients with congenital forms of IGEs, consistent with increased excitability of neurons as a result of enhanced T-type channel function. In this paper, we provide a broad overview of the roles of voltage-gated calcium channels, their mutations, and how they might contribute to the river that terminates in epilepsy.
Collapse
Affiliation(s)
- Gerald W Zamponi
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, University of Calgary, Calgary, T2N 4N1, Canada
| | | | | |
Collapse
|
30
|
BRD2 and TAP-1 genes and juvenile myoclonic epilepsy. Neurol Sci 2009; 31:53-6. [PMID: 19953286 DOI: 10.1007/s10072-009-0190-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 10/28/2009] [Indexed: 10/20/2022]
Abstract
Juvenile myoclonic epilepsy (JME) is a genetically determined common subtype of idiopathic generalized epilepsy. Linkage of JME to the chromosomal region 6p21.3 has been reported. An association has been previously observed between JME and the positional candidate, 6p21.3 linked, BRD2. Another candidate in this region is the TAP-1 gene encoding the Transporter Associated with Antigen Processing. The aim of the present study is to determine whether these two genes modulate the vulnerability to JME. While no difference was observed in the allele and genotype frequencies of BRD2 between JME and controls, an association was found between a TAP-1 haplotype and JME, suggesting that this gene may be another 6p21.3 linked vulnerability factor to JME.
Collapse
|
31
|
Abstract
Dravet syndrome (also called severe myoclonic epilepsy of infancy) is one of the most severe forms of childhood epilepsy. Most patients have heterozygous mutations in SCN1A, encoding voltage-gated sodium channel Na(v)1.1 alpha subunits. Sodium channels are modulated by beta1 subunits, encoded by SCN1B, a gene also linked to epilepsy. Here we report the first patient with Dravet syndrome associated with a recessive mutation in SCN1B (p.R125C). Biochemical characterization of p.R125C in a heterologous system demonstrated little to no cell surface expression despite normal total cellular expression. This occurred regardless of coexpression of Na(v)1.1 alpha subunits. Because the patient was homozygous for the mutation, these data suggest a functional SCN1B null phenotype. To understand the consequences of the lack of beta1 cell surface expression in vivo, hippocampal slice recordings were performed in Scn1b(-/-) versus Scn1b(+/+) mice. Scn1b(-/-) CA3 neurons fired evoked action potentials with a significantly higher peak voltage and significantly greater amplitude compared with wild type. However, in contrast to the Scn1a(+/-) model of Dravet syndrome, we found no measurable differences in sodium current density in acutely dissociated CA3 hippocampal neurons. Whereas Scn1b(-/-) mice seize spontaneously, the seizure susceptibility of Scn1b(+/-) mice was similar to wild type, suggesting that, like the parents of this patient, one functional SCN1B allele is sufficient for normal control of electrical excitability. We conclude that SCN1B p.R125C is an autosomal recessive cause of Dravet syndrome through functional gene inactivation.
Collapse
|
32
|
Affiliation(s)
- Francesco Addabbo
- Department of Medicine and Pharmacology, Renal Research Institute, New York Medical College, Valhalla 10595, USA
| | | | | |
Collapse
|
33
|
Ratnapriya R, Satishchandra P, Kumar SD, Gadre G, Reddy R, Anand A. A locus for autosomal dominant reflex epilepsy precipitated by hot water maps at chromosome 10q21.3-q22.3. Hum Genet 2009; 125:541-9. [PMID: 19266219 DOI: 10.1007/s00439-009-0648-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2008] [Accepted: 02/25/2009] [Indexed: 11/26/2022]
Abstract
Hot water epilepsy (HWE) is a form of reflex or sensory epilepsy wherein seizures are precipitated by an unusual stimulus, the contact of hot water over the head and body. Genome-wide linkage analysis of a large family with ten affected members, provided evidence of linkage (Z (max) = 3.17 at theta = 0 for D10S412) to chromosome 10q21. Analysis of five additional HWE families, for markers on chromosome 10, further strengthened the evidence of linkage to the same chromosomal region with three out of five families showing concordance for the disease haplotype and providing a two-point LOD score of 4.86 at theta = 0 and 60% penetrance for D10S412. The centromere-proximal and -distal boundaries of the critical genetic interval of about 15 Mb at 10q21.3-q22.3 were defined by D10S581 and D10S201, respectively. Sequence analysis of a group of functional candidate genes, the ion channels KCNMA1, VDAC2 and solute carriers SLC25A16, SLC29A3 revealed no potentially pathogenic mutation. We propose to carry out further analysis of positional candidate genes from this region to identify the gene responsible for this unusual neurobehavioral phenotype.
Collapse
Affiliation(s)
- Rinki Ratnapriya
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | | | | | | | | | | |
Collapse
|
34
|
Jacobs MP, Leblanc GG, Brooks-Kayal A, Jensen FE, Lowenstein DH, Noebels JL, Spencer DD, Swann JW. Curing epilepsy: progress and future directions. Epilepsy Behav 2009; 14:438-45. [PMID: 19341977 PMCID: PMC2822433 DOI: 10.1016/j.yebeh.2009.02.036] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Accepted: 02/14/2009] [Indexed: 01/10/2023]
Abstract
During the past decade, substantial progress has been made in delineating clinical features of the epilepsies and the basic mechanisms responsible for these disorders. Eleven human epilepsy genes have been identified and many more are now known from animal models. Candidate targets for cures are now based upon newly identified cellular and molecular mechanisms that underlie epileptogenesis. However, epilepsy is increasingly recognized as a group of heterogeneous syndromes characterized by other conditions that co-exist with seizures. Cognitive, emotional and behavioral co-morbidities are common and offer fruitful areas for study. These advances in understanding mechanisms are being matched by the rapid development of new diagnostic methods and therapeutic approaches. This article reviews these areas of progress and suggests specific goals that once accomplished promise to lead to cures for epilepsy.
Collapse
Affiliation(s)
- Margaret P. Jacobs
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville, MD, USA
| | - Gabrielle G. Leblanc
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Rockville, MD, USA
| | - Amy Brooks-Kayal
- Neurology and Pediatrics, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Dan H. Lowenstein
- Department of Neurology, Box 0114, University of California, San Francisco, San Francisco, CA, USA
| | | | - Dennis D. Spencer
- Department of Neurosurgery, Yale University, School of Medicine, New Haven, CT, USA
| | - John W. Swann
- Baylor College of Medicine, Texas Children’s Hospital, Houston, TX, USA
| |
Collapse
|
35
|
Bartlett VL, Johnson RL. God and genes in the caring professions: clinician and clergy perceptions of religion and genetics. AMERICAN JOURNAL OF MEDICAL GENETICS. PART C, SEMINARS IN MEDICAL GENETICS 2009; 151C:41-51. [PMID: 19170091 DOI: 10.1002/ajmg.c.30201] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Little is known about how care providers' perceptions of religion and genetics affect interactions with patients/parishioners. This study investigates clinicians' and clergy's perceptions of and experiences with religion and genetics in their clinical and pastoral interactions. This is an exploratory qualitative study designed to elicit care providers' descriptions of experiences with religion and genetics in clinical or pastoral interactions. Thirteen focus groups were conducted with members of the caring professions: physicians, nurses, and genetics counselors (clinicians), ministers and chaplains (clergy). Preliminary analysis of qualitative data is presented here. Preliminary analysis highlights four positions in professional perceptions of the relationship between science and faith. Further, differences among professional perceptions appear to influence perceptions of needed or available resources for interactions with religion and genetics. Clinicians' and clergy's perceptions of how religion and genetics relate are not defined solely by professional affiliation. These non-role-defined perceptions may affect clinical and pastoral interactions, especially regarding resources for patients and parishioners.
Collapse
Affiliation(s)
- Virginia L Bartlett
- Center for Biomedical Ethics and Society, Vanderbilt University Medical Center, 2525 West End Avenue, Nashville, TN 37203, USA.
| | | |
Collapse
|
36
|
Leussis MP, Heinrichs SC. Quality of rearing guides expression of behavioral and neural seizure phenotypes in EL mice. Brain Res 2009; 1260:84-93. [PMID: 19401172 DOI: 10.1016/j.brainres.2009.01.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2008] [Revised: 12/25/2008] [Accepted: 01/05/2009] [Indexed: 10/21/2022]
Abstract
The present studies employed behavioral and neural markers of seizure-related plasticity to examine the relative contributions of genetic predisposition versus rearing environment in generating adult phenotypes in EL mice, a stress-induced animal model of epilepsy. Early environment was manipulated by cross-fostering pups of the EL strain to a seizure-resistant CD-1 control strain of mouse. The impact of changes in rearing quality on growth,exploratory and stress-reactivity phenotypes were examined, with a focus on the role of maternal care in shaping seizure susceptibility and neural cF os activation. Improvement in maternal care imposed by replacing biological EL dams with foster CD-1 mothers was sufficient to decrease pup mortality, to increase body weight gain (+0.1 g/day) and to delay the onset of seizure susceptibility in EL offspring beyond post-natal day 80–90. Moreover,hypoactivity in hippocampus and cortex among EL offspring cross-fostered to EL, but not CD-1 control, dams suggests that changes in rearing environment were accompanied by enduring changes in brain plasticity. Thus, neural and behavioral phenotypes of EL mice are dependent upon post-partum maternal care which if systematically enhanced can postpone seizure expression.
Collapse
Affiliation(s)
- Melanie P Leussis
- Department of Psychology, Boston College, Chestnut Hill, MA 02467, USA
| | | |
Collapse
|
37
|
Weiergräber M, Henry M, Ho MS, Struck H, Hescheler J, Schneider T. Altered thalamocortical rhythmicity in Cav2.3-deficient mice. Mol Cell Neurosci 2008; 39:605-18. [DOI: 10.1016/j.mcn.2008.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2008] [Revised: 07/28/2008] [Accepted: 08/13/2008] [Indexed: 01/18/2023] Open
|
38
|
Bargary G, Mitchell KJ. Response to Cohen Kadosh and Walsh: Synaesthesia: evaluating competing theories. Trends Neurosci 2008. [DOI: 10.1016/j.tins.2008.08.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
39
|
Alfradique I, Vasconcelos MM. Juvenile myoclonic epilepsy. ARQUIVOS DE NEURO-PSIQUIATRIA 2008; 65:1266-71. [PMID: 18345445 DOI: 10.1590/s0004-282x2007000700036] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Accepted: 09/05/2007] [Indexed: 11/22/2022]
Abstract
Juvenile myoclonus epilepsy (JME) is a common epileptic syndrome, the etiology of which is genetically determined. Its onset occurs from 6 through 22 years of age, and affected patients present with myoclonic jerks, often associated with generalized tonic-clonic seizures - the most common association - and absence seizures. JME is non-progressive, and there are no abnormalities on clinical examination or intellectual deficits. Psychiatric disorders may coexist. Generalized polyspike-and-waves are the most characteristic electroencephalographic pattern. Usual neuroimaging studies show no abnormalities. Atypical presentations should be entertained, as they are likely to induce misdiagnosis. Prevention of precipitating factors and therapy with valproic acid (VPA) are able to control seizures in the great majority of patients. Whenever VPA is judged to be inappropriate, other antiepileptic drugs such as lamotrigine may be considered. Treatment should not be withdrawn, otherwise recurrences are frequent.
Collapse
Affiliation(s)
- Isabel Alfradique
- Hospital Universitário Antônio Pedro, Universidade Federal Fluminense, Niterói RJ, Brazil
| | | |
Collapse
|
40
|
Kapoor A, Satishchandra P, Ratnapriya R, Reddy R, Kadandale J, Shankar SK, Anand A. An idiopathic epilepsy syndrome linked to 3q13.3-q21 and missense mutations in the extracellular calcium sensing receptor gene. Ann Neurol 2008; 64:158-67. [DOI: 10.1002/ana.21428] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
41
|
Marshall CR, Young EJ, Pani AM, Freckmann ML, Lacassie Y, Howald C, Fitzgerald KK, Peippo M, Morris CA, Shane K, Priolo M, Morimoto M, Kondo I, Manguoglu E, Berker-Karauzum S, Edery P, Hobart HH, Mervis CB, Zuffardi O, Reymond A, Kaplan P, Tassabehji M, Gregg RG, Scherer SW, Osborne LR. Infantile spasms is associated with deletion of the MAGI2 gene on chromosome 7q11.23-q21.11. Am J Hum Genet 2008; 83:106-11. [PMID: 18565486 DOI: 10.1016/j.ajhg.2008.06.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 05/29/2008] [Accepted: 06/02/2008] [Indexed: 01/14/2023] Open
Abstract
Infantile spasms (IS) is the most severe and common form of epilepsy occurring in the first year of life. At least half of IS cases are idiopathic in origin, with others presumed to arise because of brain insult or malformation. Here, we identify a locus for IS by high-resolution mapping of 7q11.23-q21.1 interstitial deletions in patients. The breakpoints delineate a 500 kb interval within the MAGI2 gene (1.4 Mb in size) that is hemizygously disrupted in 15 of 16 participants with IS or childhood epilepsy, but remains intact in 11 of 12 participants with no seizure history. MAGI2 encodes the synaptic scaffolding protein membrane-associated guanylate kinase inverted-2 that interacts with Stargazin, a protein also associated with epilepsy in the stargazer mouse.
Collapse
|
42
|
Murai MJ, Sassonia RC, Zamboni AH, Conte FF, Martins-de-Souza D, Aparicio R, de Oliveira MG, Lopes-Cendes I. Characterization of the C-terminal half of human juvenile myoclonic epilepsy protein EFHC1: dimer formation blocks Ca2+ and Mg2+ binding to its functional EF-hand. Arch Biochem Biophys 2008; 477:131-8. [PMID: 18593566 DOI: 10.1016/j.abb.2008.06.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 06/12/2008] [Accepted: 06/12/2008] [Indexed: 10/22/2022]
Abstract
Human EFHC1 is a member of the EF-hand superfamily of Ca(2+)-binding proteins with three DM10 domains of unclear function. Point mutations in the EFHC1 gene are related to juvenile myoclonic epilepsy, a fairly common idiopathic generalized epilepsy. Here, we report the first structural and thermodynamic analyses of the EFHC1C-terminus (residues 403-640; named EFHC1C), comprising the last DM10 domain and the EF-hand motif. Circular dichroism spectroscopy revealed that the secondary structure of EFHC1C is composed by 34% of alpha-helices and 17% of beta-strands. Size exclusion chromatography and mass spectrometry showed that under oxidizing condition EFHC1C dimerizes through the formation of disulfide bond. Tandem mass spectrometry (MS/MS) analysis of peptides generated by trypsin digestion suggests that the Cys575 is involved in intermolecular S-S bond. In addition, DTNB assay showed that each reduced EFHC1C molecule has one accessible free thiol. Isothermal titration calorimetry (ITC) showed that while the interaction between Ca(2+) and EFHC1C is enthalpically driven (DeltaH=-58.6 to -67 kJ/mol and TDeltaS=-22.5 to -31 kJ/mol) the interaction between Mg(2+) and EFHC1C involves an entropic gain, and is approximately 5 times less enthalpically favorable (DeltaH=-11.7 to -14 kJ/mol and TDeltaS=21.9 to 19 kJ/mol) than for Ca(2+) binding. It was also found that under reducing condition Ca(2+) or Mg(2+) ions bind to EFHC1C in a 1/1 molar ratio, while under oxidizing condition this ratio is reduced, showing that EFHC1C dimerization blocks Ca(2+) and Mg(2+) binding.
Collapse
Affiliation(s)
- Marcelo J Murai
- Department of Medical Genetics, Faculty of Medical Sciences, Tessália Vieira de Camargo, 126, CEP 13083-970, University of Campinas, UNICAMP, Campinas, SP, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
43
|
Abstract
BACKGROUND Despite the currently available armamentarium of antiepileptic drugs, seizures are not adequately controlled in about one-third of epileptic patients. The mechanisms of antiepileptic drug resistance are multiple and not fully clarified. METHODS We conducted a literature search in PubMed and the Cochrane Library databases with the terms: "Drug Resistance" [MeSH] and "Epilepsy" [MeSH], LIMITS added to PubMed in the last 5 years, only items with abstracts, English, Spanish, Humans. REVIEW SUMMARY It is currently known that membrane transporter proteins are increased in brain tissue of refractory epileptic patients and in animal models of epilepsy and that overexpression of these transporters and their inhibition are correlated with a reduction and an increase, respectively, of epileptic drugs in epileptic tissue (pharmacokinetic hypothesis). It has also been shown that alterations in voltage-gated sodium channels and GABAA receptors are responsible for resistance to some epileptic drugs. These changes may be constitutional (genetically determined) or acquired (as a consequence of the seizures themselves or disease progression) and may seem alone or combined with each other (pharmacodynamic hypothesis). Associations have been shown between certain genetic polymorphisms and resistance to epileptic drugs, and although they have not been replicated by all authors, they constitute a very attractive line of research. More detailed knowledge of these molecular mechanisms will probably lead to the development of new strategies for pharmacological treatment of epilepsy.
Collapse
|
44
|
|
45
|
Cavalleri GL, Weale ME, Shianna KV, Singh R, Lynch JM, Grinton B, Szoeke C, Murphy K, Kinirons P, O'Rourke D, Ge D, Depondt C, Claeys KG, Pandolfo M, Gumbs C, Walley N, McNamara J, Mulley JC, Linney KN, Sheffield LJ, Radtke RA, Tate SK, Chissoe SL, Gibson RA, Hosford D, Stanton A, Graves TD, Hanna MG, Eriksson K, Kantanen AM, Kalviainen R, O'Brien TJ, Sander JW, Duncan JS, Scheffer IE, Berkovic SF, Wood NW, Doherty CP, Delanty N, Sisodiya SM, Goldstein DB. Multicentre search for genetic susceptibility loci in sporadic epilepsy syndrome and seizure types: a case-control study. Lancet Neurol 2007; 6:970-80. [PMID: 17913586 DOI: 10.1016/s1474-4422(07)70247-8] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
BACKGROUND The Epilepsy Genetics (EPIGEN) Consortium was established to undertake genetic mapping analyses with augmented statistical power to detect variants that influence the development and treatment of common forms of epilepsy. METHODS We examined common variations across 279 prime candidate genes in 2717 case and 1118 control samples collected at four independent research centres (in the UK, Ireland, Finland, and Australia). Single nucleotide polymorphism (SNP) and combined set-association analyses were used to examine the contribution of genetic variation in the candidate genes to various forms of epilepsy. FINDINGS We did not identify clear, indisputable common genetic risk factors that contribute to selected epilepsy subphenotypes across multiple populations. Nor did we identify risk factors for the general all-epilepsy phenotype. However, set-association analysis on the most significant p values, assessed under permutation, suggested the contribution of numerous SNPs to disease predisposition in an apparent population-specific manner. Variations in the genes KCNAB1, GABRR2, KCNMB4, SYN2, and ALDH5A1 were most notable. INTERPRETATION The underlying genetic component to sporadic epilepsy is clearly complex. Results suggest that many SNPs contribute to disease predisposition in an apparently population-specific manner. However, subtle differences in phenotyping across cohorts, combined with a poor understanding of how the underlying genetic component to epilepsy aligns with current phenotypic classifications, might also account for apparent population-specific genetic risk factors. Variations across five genes warrant further study in independent cohorts to clarify the tentative association.
Collapse
Affiliation(s)
- Gianpiero L Cavalleri
- Department of Clinical Neurological Sciences and Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland Research Institute, and Division of Neurology, Beaumont Hospital, Dublin, Ireland
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
46
|
Tang B, Sander T, Craven KB, Hempelmann A, Escayg A. Mutation analysis of the hyperpolarization-activated cyclic nucleotide-gated channels HCN1 and HCN2 in idiopathic generalized epilepsy. Neurobiol Dis 2007; 29:59-70. [PMID: 17931874 DOI: 10.1016/j.nbd.2007.08.006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2007] [Revised: 08/02/2007] [Accepted: 08/06/2007] [Indexed: 12/01/2022] Open
Abstract
Hyperpolarization-activated cyclic nucleotide-gated (HCN1-4) channels play an important role in the regulation of neuronal rhythmicity. In the present study we describe the mutation analysis of HCN1 and HCN2 in 84 unrelated patients with idiopathic generalized epilepsy (IGE). Several functional variants were identified including the amino acid substitution R527Q in HCN2 exon 5. HCN2 channels containing the R527Q variant demonstrated a trend towards a decreased slope of the conductance-voltage relation. We also identified a variant in the splice donor site of HCN2 exon 5 that results in the formation of a cryptic splice donor. In HCN1, the amino acid substitution A881T was identified in one sporadic IGE patient but was not observed in 510 controls. Seven variants were examined further in a case-control association study consisting of a larger cohort of IGE patients. Further studies are warranted to more clearly establish the contribution of HCN1 and HCN2 dysfunction to the genetic variance of common IGE syndromes.
Collapse
Affiliation(s)
- Bin Tang
- Department of Human Genetics, Emory University, 615 Michael Street, Whitehead Building, Suite 301, Atlanta, GA 30322, USA
| | | | | | | | | |
Collapse
|
47
|
Sander T, Gaus V. Genetik der idiopathischen Epilepsien. MED GENET-BERLIN 2007. [DOI: 10.1007/s11825-007-0037-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Zusammenfassung
Die idiopathischen Epilepsien sind ätiologisch überwiegend genetisch determiniert und repräsentieren etwa 40% aller Epilepsien. Mutationen in Genen von Ionenkanälen spielen eine zentrale Rolle bei der Pathogenese von eher monogenen Epilepsieformen. Molekulargenetische Forschungsansätze bei den häufigen genetisch komplexen Epilepsien stehen noch am Anfang der Aufklärung der molekularen Mechanismen der Epileptogenese. Erst die umfassende Identifizierung der wichtigsten genetischen Risikofaktoren wird es ermöglichen, verlässliche individuelle Risikoprofile zu erstellen und präventiv ausgerichtete Therapieansätze zu entwickeln.
Collapse
Affiliation(s)
- T. Sander
- Aff1_37 grid.6190.e 0000000085803777 Cologne Center for Genomics Universität zu Köln Zülpicher Straße 47 50674 Köln Deutschland
| | - V. Gaus
- Aff2_37 grid.418434.e Neurologische Klinik und Poliklinik Charité – Campus Virchow Klinikum Berlin Deutschland
| |
Collapse
|
48
|
Heron SE, Scheffer IE, Berkovic SF, Dibbens LM, Mulley JC. Channelopathies in idiopathic epilepsy. Neurotherapeutics 2007; 4:295-304. [PMID: 17395140 DOI: 10.1016/j.nurt.2007.01.009] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Approximately 70% of all patients with epilepsy lack an obvious extraneous cause and are presumed to have a predominantly genetic basis. Both familial and de novo mutations in neuronal voltage-gated and ligand-gated ion channel subunit genes have been identified in autosomal dominant epilepsies. However, patients with dominant familial mutations are rare and the majority of idiopathic epilepsy is likely to be the result of polygenic susceptibility alleles (complex epilepsy). Data on the identity of the genes involved in complex epilepsy is currently sparse but again points to neuronal ion channels. The number of genes and gene families associated with epilepsy is rapidly increasing and this increase is likely to escalate over the coming years with advances in mutation detection technologies. The genetic heterogeneity underlying idiopathic epilepsy presents challenges for the rational selection of therapies targeting particular ion channels. Too little is currently known about the genetic architecture of the epilepsies, and genetic testing for the known epilepsy genes remains costly. Pharmacogenetic studies have yet to explain why 30% of patients do not respond to the usual antiepileptic drugs. Despite this, the recognition that the idiopathic epilepsies are a group of channelopathies has, to a limited extent, explained the therapeutic action of the common antiepileptic drugs and has assisted clinical diagnosis of some epilepsy syndromes.
Collapse
Affiliation(s)
- Sarah E Heron
- Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, South Australia 5006.
| | | | | | | | | |
Collapse
|
49
|
Wolfe DM, Pearce DA. Channeling studies in yeast: yeast as a model for channelopathies? Neuromolecular Med 2007; 8:279-306. [PMID: 16775381 DOI: 10.1385/nmm:8:3:279] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2005] [Revised: 11/30/1999] [Accepted: 01/09/2006] [Indexed: 01/30/2023]
Abstract
Regulation of the concentration of ions within a cell is mediated by their specific transport and sequestration across cellular membranes. This regulation constitutes a major factor in the maintenance of correct cellular homeostasis, with the transport occurring through the action of a large number of different channel proteins localized to the plasma membrane as well as to various organelles. These ion channels vary in specificity from broad (cationic vs anionic) to highly selective (chloride vs sodium). Mutations in many of these channels result in a large number of human diseases, collectively termed channelopathies. Characterization of many of these channels has been undertaken in a variety of both prokaryotic and eukaryotic organisms. Among these organisms is the budding yeast Saccharomyces cerevisiae. Possessing a fully annotated genome, S. cerevisiae would appear to be an ideal organism in which to study this class of proteins associated to diseases. We have compiled and reviewed a list of yeast ion channels, each possessing a human homolog implicated in a channelopathy. Although yeast has been used for the study of other human disease, it has been under utilized for channelopathy research. The utility of using yeast as a model system for studying ion channels associated to human disease is illustrated using yeast lacking the GEF1 gene product that encodes the human homolog to the chloride channel CLC-3.
Collapse
Affiliation(s)
- Devin M Wolfe
- Center for Aging and Developmental Biology, Aab Institute of Biomedical Sciences, University of Rochester School of Medicine and Dentistry, Rochester, New York 14642, USA
| | | |
Collapse
|
50
|
Béri-Deixheimer M, Gregoire MJ, Toutain A, Brochet K, Briault S, Schaff JL, Leheup B, Jonveaux P. Genotype–phenotype correlations to aid in the prognosis of individuals with uncommon 20q13.33 subtelomere deletions: a collaborative study on behalf of the ‘association des Cytogénéticiens de langue Française’. Eur J Hum Genet 2007; 15:446-52. [PMID: 17290276 DOI: 10.1038/sj.ejhg.5201784] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The identification of subtelomeric rearrangements as a cause of mental retardation has made a considerable contribution to diagnosing patients with mental retardation. It is remarkable that for certain subtelomeric regions, deletions have hardly ever been reported so far. All the laboratories from the 'Association des Cytogénéticiens de Langue Française' were surveyed for cases where an abnormality of the subtelomere FISH analysis had been ascertained. Among 1511 cases referred owing to unexplained mental retardation, 115 (7.6%) patients showed a clinically significant subtelomeric abnormality. We report the clinical features and the molecular cytogenetic delineation of isolated de novo deletions on 20q13.33 in two cases. Detailed mapping was performed by micro-array CGH in one patient and confirmed by FISH in the two patients. We compare our data with the only three patients reported in the literature. Both patients shared a deleted region of approximately 1.33 Mb including 40 genes, with a 324 kb difference between the two patients. Haploinsufficiency for CHRNA4 and ARFGAP1 may have contributed towards a severe phenotype. In addition, the data in all patients suggest that haploinsufficiency for SOX18 may not cause the hypotrichosis-lymphedema-telangiectasia syndrome, or causes milder disease. Our study gives important information by defining the size of imbalance and better predicting the phenotype. Two clinically distinct phenotypes may be drawn, a mild mental retardation or a more complex and severe phenotype, according to the presence or absence of the CHRNA4 and ARFGAP1 genes respectively.
Collapse
|