1
|
dos Santos BP, Marinho CRM, Marques TEBS, Angelo LKG, Malta MVDS, Duzzioni M, de Castro OW, Leite JP, Barbosa FT, Gitaí DLG. Genetic susceptibility in Juvenile Myoclonic Epilepsy: Systematic review of genetic association studies. PLoS One 2017; 12:e0179629. [PMID: 28636645 PMCID: PMC5479548 DOI: 10.1371/journal.pone.0179629] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Accepted: 06/01/2017] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Several genetic association investigations have been performed over the last three decades to identify variants underlying Juvenile Myoclonic Epilepsy (JME). Here, we evaluate the accumulating findings and provide an updated perspective of these studies. METHODOLOGY A systematic literature search was conducted using the PubMed, Embase, Scopus, Lilacs, epiGAD, Google Scholar and Sigle up to February 12, 2016. The quality of the included studies was assessed by a score and classified as low and high quality. Beyond outcome measures, information was extracted on the setting for each study, characteristics of population samples and polymorphisms. RESULTS Fifty studies met eligibility criteria and were used for data extraction. With a single exception, all studies used a candidate gene approach, providing data on 229 polymorphisms in or near 55 different genes. Of variants investigating in independent data sets, only rs2029461 SNP in GRM4, rs3743123 in CX36 and rs3918149 in BRD2 showed a significant association with JME in at least two different background populations. The lack of consistent associations might be due to variations in experimental design and/or limitations of the approach. CONCLUSIONS Thus, despite intense research evidence established, specific genetic variants in JME susceptibility remain inconclusive. We discussed several issues that may compromise the quality of the results, including methodological bias, endophenotype and potential involvement of epigenetic factors. PROSPERO REGISTRATION NUMBER CRD42016036063.
Collapse
Affiliation(s)
- Bruna Priscila dos Santos
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Chiara Rachel Maciel Marinho
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | | | - Layanne Kelly Gomes Angelo
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Maísa Vieira da Silva Malta
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Marcelo Duzzioni
- Department of Pharmacology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - Olagide Wagner de Castro
- Department of Physiology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| | - João Pereira Leite
- Division of Neurology, Department of Neurosciences and Behavioral Sciences, Ribeirão Preto School of Medicine, University of São Paulo, Ribeirão Preto, São Paulo, Brazil
| | | | - Daniel Leite Góes Gitaí
- Department of Cellular and Molecular Biology, Institute of Biological Sciences and Health, Federal University of Alagoas, Maceio, Alagoas, Brazil
| |
Collapse
|
2
|
Santhosh NS, Sinha S, Satishchandra P. Epilepsy: Indian perspective. Ann Indian Acad Neurol 2014; 17:S3-S11. [PMID: 24791085 PMCID: PMC4001222 DOI: 10.4103/0972-2327.128643] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 02/17/2014] [Accepted: 02/17/2014] [Indexed: 12/05/2022] Open
Abstract
There are 50 million people living with epilepsy worldwide, and most of them reside in developing countries. About 10 million persons with epilepsy are there in India. Many people with active epilepsy do not receive appropriate treatment for their condition, leading to large treatment gap. The lack of knowledge of antiepileptic drugs, poverty, cultural beliefs, stigma, poor health infrastructure, and shortage of trained professionals contribute for the treatment gap. Infectious diseases play an important role in seizures and long-term burden causing both new-onset epilepsy and status epilepticus. Proper education and appropriate health care services can make tremendous change in a country like India. There have been many original researches in various aspects of epilepsy across India. Some of the geographically specific epilepsies occur only in certain regions of our country which have been highlighted by authors. Even the pre-surgical evaluation and epilepsy surgery in patients with drug-resistant epilepsy is available in many centers in our country. This article attempts to provide a complete preview of epilepsy in India.
Collapse
Affiliation(s)
| | - Sanjib Sinha
- Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India
| | | |
Collapse
|
3
|
Li S, Liu ZC, Yin SJ, Chen YT, Yu HL, Zeng J, Zhang Q, Zhu F. Human endogenous retrovirus W family envelope gene activates the small conductance Ca2+-activated K+ channel in human neuroblastoma cells through CREB. Neuroscience 2013; 247:164-74. [PMID: 23727510 DOI: 10.1016/j.neuroscience.2013.05.033] [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: 02/26/2013] [Revised: 05/17/2013] [Accepted: 05/17/2013] [Indexed: 11/25/2022]
Abstract
Numerous studies have shown that human endogenous retrovirus W family (HERV-W) envelope gene (env) is related to various diseases but the underlying mechanism has remained poorly understood. Our previous study showed that there was abnormal expression of HERV-W env in sera of patients with schizophrenia. In this paper, we reported that overexpression of the HERV-W env elevated the levels of small conductance Ca(2+)-activated K(+) channel protein 3 (SK3) in human neuroblastoma cells. Using a luciferase reporter system and RNA interference method, we found that functional cAMP response element site was required for the expression of SK3 triggered by HERV-W env. In addition, it was also found that the SK3 channel was activated by HERV-W env. Further study indicated that cAMP response element-binding protein (CREB) was required for the activation of the SK3 channel. Thus, a novel signaling mechanism of how HERV-W env influences neuronal activity and contributes to mental illnesses such as schizophrenia was proposed.
Collapse
Affiliation(s)
- S Li
- Department of Medical Microbiology, School of Medicine, Wuhan University, Wuhan 430071, PR China
| | | | | | | | | | | | | | | |
Collapse
|
4
|
Grube S, Gerchen MF, Adamcio B, Pardo LA, Martin S, Malzahn D, Papiol S, Begemann M, Ribbe K, Friedrichs H, Radyushkin KA, Müller M, Benseler F, Riggert J, Falkai P, Bickeböller H, Nave KA, Brose N, Stühmer W, Ehrenreich H. A CAG repeat polymorphism of KCNN3 predicts SK3 channel function and cognitive performance in schizophrenia. EMBO Mol Med 2011; 3:309-19. [PMID: 21433290 PMCID: PMC3377084 DOI: 10.1002/emmm.201100135] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2010] [Revised: 02/24/2011] [Accepted: 02/25/2011] [Indexed: 12/11/2022] Open
Abstract
KCNN3, encoding the small conductance calcium-activated potassium channel SK3, harbours a polymorphic CAG repeat in the amino-terminal coding region with yet unproven function. Hypothesizing that KCNN3 genotypes do not influence susceptibility to schizophrenia but modify its phenotype, we explored their contribution to specific schizophrenic symptoms. Using the Göttingen Research Association for Schizophrenia (GRAS) data collection of schizophrenic patients (n = 1074), we performed a phenotype-based genetic association study (PGAS) of KCNN3. We show that long CAG repeats in the schizophrenic sample are specifically associated with better performance in higher cognitive tasks, comprising the capacity to discriminate, select and execute (p < 0.0001). Long repeats reduce SK3 channel function, as we demonstrate by patch-clamping of transfected HEK293 cells. In contrast, modelling the opposite in mice, i.e. KCNN3 overexpression/channel hyperfunction, leads to selective deficits in higher brain functions comparable to those influenced by SK3 conductance in humans. To conclude, KCNN3 genotypes modify cognitive performance, shown here in a large sample of schizophrenic patients. Reduction of SK3 function may constitute a pharmacological target to improve cognition in schizophrenia and other conditions with cognitive impairment.
Collapse
Affiliation(s)
- Sabrina Grube
- Divison of Clinical Neuroscience, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Abstract
Juvenile myoclonic epilepsy (JME) is a common epilepsy syndrome that begins most frequently in the early teenage years. It is officially classified as a type of idiopathic generalized epilepsy and is often under-recognized or misdiagnosed. This syndrome has a strong genetic component with multiple gene mutations being associated with the clinical presentation. Based upon genetic associations, there may be multiple pathophysiologic mechanisms for the disorder; the pathophysiology has not been clearly defined. A diagnosis of JME is made using the clinical history and EEG findings. Valproic acid is the primary antiepileptic drug (AED) used for JME, but some newer AEDs may be effective alternatives. Selection of an appropriate AED is essential to the proper management of JME, because of the possibility of exacerbation of seizures by some AEDs and the adverse effect profiles of effective drugs. It is important for clinicians to understand JME to correctly diagnose and manage patients with this syndrome.
Collapse
Affiliation(s)
- Timothy E Welty
- Department of Pharmacy Practice, McWhorter School of Pharmacy, Samford University, Birmingham, Alabama 35229, USA.
| |
Collapse
|
6
|
Gargus JJ. Ion channel functional candidate genes in multigenic neuropsychiatric disease. Biol Psychiatry 2006; 60:177-85. [PMID: 16497276 DOI: 10.1016/j.biopsych.2005.12.008] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2005] [Revised: 11/15/2005] [Accepted: 12/15/2005] [Indexed: 10/25/2022]
Abstract
Scores of monogenic Mendelian ion channel diseases serve to anchor the pathophysiology of the channelopathies, but there are also now clear examples of environmental, pharmacogenetic, and acquired channelopathy mechanisms. The cardinal feature of heritable ion channel disease is a periodic disturbance of rhythmic function in constitutionally hyperexcitable tissue. While the complexity of neuroanatomy obscures functional analysis of mutations causing monogenic seizure, ataxia, or migraine syndromes, extrapolation from the cardiac (Long QT [LQT]) and muscle (Periodic Paralysis) channelopathy syndromes provides a simplified predictive framework of molecular pathology: electrically stabilizing potassium ion (K(+)) and chloride ion (Cl(-)) channels, likely having lesions that diminish their current, and excitatory Na(+) channels, likely having gain-of-function lesions. The voltage-gated calcium channel gene family that contains CACNA1C, the newest LQT locus, causing Timothy Syndrome with a phenotype including autism, has proven to be particularly informative for its members' ability to tie the various central nervous system (CNS) phenotypes together in an interpretable fashion, now including direct extension to the classically multigenic neuropsychiatric phenotypes. Features of a promising ion channel candidate gene arise from its broad locus, gene family, nature of alleles, physiology and pharmacology, tissue expression profile, and phenotype in model organisms. KCNN3 is explored as a paradigm to consider.
Collapse
Affiliation(s)
- J Jay Gargus
- Department of Physiology, Section of Human Genetics, University of California, Irvine, California 92697-4034, USA.
| |
Collapse
|
7
|
Siwach P, Pophaly SD, Ganesh S. Genomic and Evolutionary Insights into Genes Encoding Proteins with Single Amino Acid Repeats. Mol Biol Evol 2006; 23:1357-69. [PMID: 16618963 DOI: 10.1093/molbev/msk022] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Mutations causing expansion of amino acid repeats are responsible for 19 hereditary disorders. Repeats in several other proteins also show length variations. These observations prompted us to identify single amino acid repeat-containing proteins (SARPs) in humans and to understand their functional and evolutionary significance. We identified 8812 SARPs containing 17 146 repeat domains, each harboring 4 or more residues. In all, 5% of SARPs (471) showed repeat length variations, and nearly 84% of them (394) have repeats of 10 residues or less. We find that SARPs are involved in functions that require formation of multiprotein complexes. Nearly 78% (6859) of the SARPs did not find a paralogue in the human proteome, and such proteins are considered as orphan SARPs. Orphan SARPs show longer repeat stretches, longer peptide length, and lower expression levels as compared with SARPs belonging to protein family. Because the intensity of gene expression is known to relate inversely with the rate of protein sequence evolution, our results suggest that the orphan SARPs evolve faster than the familial forms and therefore are under a weaker selection pressure. We also find that while GC-rich codons are favored for coding the repeat tracts of SARPs, specific codons and not nucleotide motifs per se are selected, suggesting functional constraints placed on the usage of codons. One of the constraints could be the mRNA stability as clustering of rare codons is known to destabilize the transcripts and rare codons are not favored for coding repeat tracts. Genes encoding polymorphic SARPs show preferential localization toward the telomeric segments. Further, the sex-specific recombination rates of the chromosomal locus strongly correlate with the parental gender that influence the repeat instability in disorder caused by dynamic mutation. Therefore, instability associated with repeats might be driven by processes that are specific to sperm or oocyte development, and the recombination frequency might play a positive role in this process.
Collapse
Affiliation(s)
- Pratibha Siwach
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology, Kanpur, India
| | | | | |
Collapse
|