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Asadi-Pooya AA, Malekpour M, Taherifard E, Mallahzadeh A, Farjoud Kouhanjani M. Coexistence of temporal lobe epilepsy and idiopathic generalized epilepsy. Epilepsy Behav 2024; 151:109602. [PMID: 38160579 DOI: 10.1016/j.yebeh.2023.109602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2023] [Revised: 12/07/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
OBJECTIVE We investigated the frequency of coexistence of temporal lobe epilepsy (TLE) and idiopathic generalized epilepsy (IGE) in a retrospective database study. We also explored the underlying pathomechanisms of the coexistence of TLE and IGE based on the available information, using bioinformatics tools. METHODS The first phase of the investigation was a retrospective study. All patients with an electro-clinical diagnosis of epilepsy were studied at the outpatient epilepsy clinic at Shiraz University of Medical Sciences, Shiraz, Iran, from 2008 until 2023. In the second phase, we searched the following databases for genetic variations (epilepsy-associated genetic polymorphisms) that are associated with TLE or syndromes of IGE: DisGeNET, genome-wide association study (GWAS) Catalog, epilepsy genetic association database (epiGAD), and UniProt. We also did a separate literature search using PubMed. RESULTS In total, 3760 patients with epilepsy were registered at our clinic; four patients with definitely mixed TLE and IGE were identified; 0.1% of all epilepsies. We could identify that rs1883415 of ALDH5A1, rs137852779 of EFHC1, rs211037 of GABRG2, rs1130183 of KCNJ10, and rs1045642 of ABCB1 genes are shared between TLE and syndromes of IGE. CONCLUSION While coexistence of TLE and IGE is a rare phenomenon, this could be explained by shared genetic variations.
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Affiliation(s)
- Ali A Asadi-Pooya
- Epilepsy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Jefferson Comprehensive Epilepsy Center, Department of Neurology, Thomas Jefferson University, Philadelphia, PA, USA.
| | - Mahdi Malekpour
- Epilepsy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ehsan Taherifard
- Epilepsy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Arashk Mallahzadeh
- Epilepsy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
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Aslan-Kara K, Dündar-Yenilmez E, Ateş E, Alparslan MM, Peköz T, Bozdemir H, Tuli A. EFHC1 gene mutation profile of Turkish JME patients and its association with disease risk. Seizure 2024; 114:79-83. [PMID: 38088014 DOI: 10.1016/j.seizure.2023.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Revised: 11/28/2023] [Accepted: 12/01/2023] [Indexed: 01/23/2024] Open
Abstract
OBJECTIVES Juvenile myoclonic epilepsy (JME) is a common form of generalized epilepsy with an important genetic component. This cohort study aimed to examine the frequency of EFHC1 gene variants in Turkish JME patients and a healthy control group and evaluate the association between these mutations and disease risk. METHODS We screened 72 JME patients with a mean age of 31.8 ± 9.9 (20-65) years and 35 controls with a mean age of 29.1 ± 7.6 (17-50) years from southern Turkey using direct sequencing analyses. RESULTS EFCH1 single nucleotide variants were detected in 24 of 72 JME patients and 3 of 35 controls. The most common mutations were R182H in JME patients (p = 0.010) and 3'UTR in the control group (p < 0.001). The R182H mutation is a common variant in JME (95 % CI: 1.232-76.580, p = 0.031) and the 3'UTR mutation may be associated with lower risk of JME in the Turkish population (95 % CI: 13.89-166.67, p < 0.001). SIGNIFICANCE Our results indicate that EFHC1 gene variants carry a risk for JME and the 3'UTR variant may have a protective role against JME in the Turkish population. Screening for other genes is needed to further clarify the genetic inheritance of JME in Turkish patients.
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Affiliation(s)
- Kezban Aslan-Kara
- Department of Neurology, School of Medicine, Çukurova University Faculty of Medicine, Sarıçam-Adana 01330, Türkiye.
| | - Ebru Dündar-Yenilmez
- Department of Medical Biochemistry, Çukurova University Faculty of Medicine, Türkiye
| | - Elçin Ateş
- Department of Neurology, School of Medicine, Çukurova University Faculty of Medicine, Sarıçam-Adana 01330, Türkiye
| | | | - Taylan Peköz
- Department of Neurology, School of Medicine, Çukurova University Faculty of Medicine, Sarıçam-Adana 01330, Türkiye
| | - Hacer Bozdemir
- Department of Neurology, School of Medicine, Çukurova University Faculty of Medicine, Sarıçam-Adana 01330, Türkiye
| | - Abdullah Tuli
- Department of Medical Biochemistry, Çukurova University Faculty of Medicine, Türkiye
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Ithal D, Sukumaran SK, Bhattacharjee D, Vemula A, Nadella R, Mahadevan J, Sud R, Viswanath B, Purushottam M, Jain S. Exome hits demystified: The next frontier. Asian J Psychiatr 2021; 59:102640. [PMID: 33892377 DOI: 10.1016/j.ajp.2021.102640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/26/2021] [Indexed: 12/13/2022]
Abstract
Severe mental illnesses such as schizophrenia and bipolar disorder have complex inheritance patterns, involving both common and rare variants. Whole exome sequencing is a promising approach to find out the rare genetic variants. We had previously reported several rare variants in multiplex families with severe mental illnesses. The current article tries to summarise the biological processes and pattern of expression of genes harbouring the aforementioned variants, linking them to known clinical manifestations through a methodical narrative review. Of the 28 genes considered for this review from 7 families with multiple affected individuals, 6 genes are implicated in various neuropsychiatric manifestations including some variations in the brain morphology assessed by magnetic resonance imaging. Another 15 genes, though associated with neuropsychiatric manifestations, did not have established brain morphological changes whereas the remaining 7 genes did not have any previously recorded neuropsychiatric manifestations at all. Wnt/b-catenin signaling pathway was associated with 6 of these genes and PI3K/AKT, calcium signaling, ERK, RhoA and notch signaling pathways had at least 2 gene associations. We present a comprehensive review of biological and clinical knowledge about the genes previously reported in multiplex families with severe mental illness. A 'disease in dish approach' can be helpful to further explore the fundamental mechanisms.
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Affiliation(s)
- Dhruva Ithal
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Salil K Sukumaran
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Debanjan Bhattacharjee
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Alekhya Vemula
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Ravi Nadella
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Jayant Mahadevan
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Reeteka Sud
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Biju Viswanath
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
| | - Meera Purushottam
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India.
| | - Sanjeev Jain
- Department of Psychiatry, National Institute of Mental Health and Neuro Sciences, Bengaluru, Karnataka, India
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Mutational Analysis of Myoclonin1 Gene in Pakistani Juvenile Myoclonic Epilepsy Patients. BIOMED RESEARCH INTERNATIONAL 2021; 2021:7509825. [PMID: 33969125 PMCID: PMC8081613 DOI: 10.1155/2021/7509825] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 02/03/2021] [Accepted: 04/10/2021] [Indexed: 02/06/2023]
Abstract
Juvenile myoclonic epilepsy (JME) is the most prevalent and genetically heterogeneous form of epilepsy and accounts for 10–30% of all the cases worldwide. Ef-hand domain- (c-terminal-) containing protein 1 (EFHC1) encodes for a nonion channel protein and mutations in this gene have been extensively reported in different populations to play a causative role in JME. Linkage between JME and 6p11-12 locus has already been confirmed in Mexican and Dutch families. A case-control study was conducted on Pakistani JME patients for the first time, aimed at finding out EFHC1 mutations that have been reported in different populations. For this purpose, 66 clinically diagnosed JME patients and 108 control subjects were included in the study. Blood samples were collected from all the participants, and DNA was isolated from the lymphocytes by the modified organic method. Total 3 exons of EFHC1, harboring extensively reported mutations, were selected for genotypic analysis. We identified three heterozygous variants, R159W, V460A, P436P, and one insertion in the current study. V460A, an uncommon variant identified herein, has recently been reported in public databases in an unphenotyped American individual. This missense variant was found in 3 Pakistani JME patients from 2 unrelated families. However, in silico analysis showed that V460A may possibly be a neutral variant. While the absence of a majority of previously reported mutations in our population suggests that most of the mutations of EFHC1 are confined to particular ethnicities and are not evenly distributed across the world. However, to imply the causation, the whole gene and larger number of JME patients should be screened in this understudied population.
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Suzuki T, Inoue I, Yamakawa K. Epilepsy protein Efhc1/myoclonin1 is expressed in cells with motile cilia but not in neurons or mitotic apparatuses in brain. Sci Rep 2020; 10:22076. [PMID: 33328576 PMCID: PMC7744795 DOI: 10.1038/s41598-020-79202-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/04/2020] [Indexed: 11/09/2022] Open
Abstract
EFHC1 gene encodes the myoclonin1 protein, also known as Rib72-1. Pathogenic variants in EFHC1 have been reported in patients with juvenile myoclonic epilepsy (JME). Although several studies of immunohistological investigations reproducibly showed that the myoclonin1 is expressed in cells with flagella and motile cilia such as sperm, trachea and ependymal cells lining the brain ventricles, whether myoclonin1 is also expressed in neurons still remains controversial. Here we investigated myoclonin1 expression using widely-used polyclonal (mRib72-pAb) and self-made monoclonal (6A3-mAb) anti-myoclonin1 antibodies together with Efhc1 homozygous knock-out (Efhc1-/-) mice. All of the western blot, immunocytochemical, and immunohistochemical analyses showed that mRib72-pAb crossreacts with several mouse proteins besides myoclonin1, while 6A3-mAb specifically recognized myoclonin1 and detected it only in cells with motile cilia but not in neurons. In dividing cells, mRib72-pAb signals were observed at the midbody (intercellular bridge) and mitotic spindle, but 6A3-mAb did not show any signals at these apparatuses. We further found that the complete elimination of myoclonin1 in Efhc1-/- mouse did not critically affect cell division and migration of neurons in cerebral cortex. These results indicate that myoclonin1 is not expressed in neurons, not a regulator of cell division or neuronal migration during cortical development, but expressed in choroid plexus and ependymal cells and suggest that EFHC1 mutation-dependent JME is a motile ciliopathy.
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Affiliation(s)
- Toshimitsu Suzuki
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Science, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi, 467-8601, Japan.,Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Ikuyo Inoue
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Kazuhiro Yamakawa
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Science, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya, Aichi, 467-8601, Japan. .,Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.
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Gonsales MC, Ribeiro PAO, Betting LE, Alvim MKM, Guerreiro CM, Yasuda CL, Gitaí DLG, Cendes F, Lopes-Cendes I. Revisiting the clinical impact of variants in EFHC1 in patients with different phenotypes of genetic generalized epilepsy. Epilepsy Behav 2020; 112:107469. [PMID: 33181902 DOI: 10.1016/j.yebeh.2020.107469] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 08/20/2020] [Accepted: 08/30/2020] [Indexed: 01/27/2023]
Abstract
The most common form of genetic generalized epilepsy (GGE) is juvenile myoclonic epilepsy (JME), which accounts for 5 to 10% of all epilepsy cases. The gene EFHC1 has been implicated as a putative cause of JME. However, it remains debatable whether testing for EFHC1 mutations should be included in the diagnostic epilepsy gene panels. To investigate the clinical utility of EFHC1 testing, we studied 125 individuals: 100 with JME and 25 with other GGEs. We amplified and sequenced all EFHC1 coding exons. Then, we predicted the pathogenicity or benign impact of the variants using the analyses proposed by the American College of Medical Genetics and Genomics (ACMG)/Association for Molecular Pathology (AMP). Mutation screening revealed 11 missense variants in 44 probands with JME (44%) and one of the seven individuals with generalized tonic-clonic seizures on awakening (14%). Six of the 11 variants (54%) were classified as 'benign,' and the remaining variants were considered variants of uncertain significance (VUS). There is currently a limitation to test for genes that predispose an individual to complex, nonmonogenic phenotypes. Thus, we show suggestive evidence that EFHC1 testing lacks a scientific foundation based on the disputed nature of the gene-disease relationship and should be currently limited to research purposes.
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Affiliation(s)
- Marina C Gonsales
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil
| | - Patrícia A O Ribeiro
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil
| | - Luiz E Betting
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil
| | - Marina K M Alvim
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil
| | - Carlos M Guerreiro
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil
| | - Clarissa L Yasuda
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil
| | - Daniel L G Gitaí
- Institute of Biological Sciences and Health, Federal University of Alagoas (UFAL), Maceió, AL, Brazil
| | - Fernando Cendes
- Department of Neurology, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil
| | - Iscia Lopes-Cendes
- Department of Medical Genetics and Genomic Medicine, School of Medical Sciences, University of Campinas (UNICAMP), Campinas, SP, Brazil; The Brazilian Institute of Neuroscience and Neurotechnology (BRAINN), Campinas, SP, Brazil.
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Thakran S, Guin D, Singh P, Singh P, Kukal S, Rawat C, Yadav S, Kushwaha SS, Srivastava AK, Hasija Y, Saso L, Ramachandran S, Kukreti R. Genetic Landscape of Common Epilepsies: Advancing towards Precision in Treatment. Int J Mol Sci 2020; 21:E7784. [PMID: 33096746 PMCID: PMC7589654 DOI: 10.3390/ijms21207784] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 10/09/2020] [Accepted: 10/14/2020] [Indexed: 12/15/2022] Open
Abstract
Epilepsy, a neurological disease characterized by recurrent seizures, is highly heterogeneous in nature. Based on the prevalence, epilepsy is classified into two types: common and rare epilepsies. Common epilepsies affecting nearly 95% people with epilepsy, comprise generalized epilepsy which encompass idiopathic generalized epilepsy like childhood absence epilepsy, juvenile myoclonic epilepsy, juvenile absence epilepsy and epilepsy with generalized tonic-clonic seizure on awakening and focal epilepsy like temporal lobe epilepsy and cryptogenic focal epilepsy. In 70% of the epilepsy cases, genetic factors are responsible either as single genetic variant in rare epilepsies or multiple genetic variants acting along with different environmental factors as in common epilepsies. Genetic testing and precision treatment have been developed for a few rare epilepsies and is lacking for common epilepsies due to their complex nature of inheritance. Precision medicine for common epilepsies require a panoramic approach that incorporates polygenic background and other non-genetic factors like microbiome, diet, age at disease onset, optimal time for treatment and other lifestyle factors which influence seizure threshold. This review aims to comprehensively present a state-of-art review of all the genes and their genetic variants that are associated with all common epilepsy subtypes. It also encompasses the basis of these genes in the epileptogenesis. Here, we discussed the current status of the common epilepsy genetics and address the clinical application so far on evidence-based markers in prognosis, diagnosis, and treatment management. In addition, we assessed the diagnostic predictability of a few genetic markers used for disease risk prediction in individuals. A combination of deeper endo-phenotyping including pharmaco-response data, electro-clinical imaging, and other clinical measurements along with genetics may be used to diagnose common epilepsies and this marks a step ahead in precision medicine in common epilepsies management.
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Affiliation(s)
- Sarita Thakran
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
| | - Debleena Guin
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Department of Bioinformatics, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India;
| | - Pooja Singh
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
| | - Priyanka Singh
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
| | - Samiksha Kukal
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
| | - Chitra Rawat
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
| | - Saroj Yadav
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
| | - Suman S. Kushwaha
- Department of Neurology, Institute of Human Behaviour and Allied Sciences, Dilshad Garden, Delhi 110095, India;
| | - Achal K. Srivastava
- Department of Neurology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029, India;
| | - Yasha Hasija
- Department of Bioinformatics, Delhi Technological University, Shahbad Daulatpur, Main Bawana Road, Delhi 110042, India;
| | - Luciano Saso
- Department of Physiology and Pharmacology “Vittorio Erspamer”, Sapienza University of Rome, P. le Aldo Moro 5, 00185 Rome, Italy;
| | - Srinivasan Ramachandran
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
- G N Ramachandran Knowledge Centre, Council of Scientific and Industrial Research (CSIR)—Institute of Genomics and Integrative Biology (IGIB), New Delhi 110007, India
| | - Ritushree Kukreti
- Genomics and Molecular Medicine Unit, Institute of Genomics and Integrative Biology (IGIB), Council of Scientific and Industrial Research (CSIR), Delhi 110007, India; (S.T.); (D.G.); (P.S.); (P.S.); (S.K.); (C.R.); (S.Y.)
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India;
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Gilsoul M, Grisar T, Delgado-Escueta AV, de Nijs L, Lakaye B. Subtle Brain Developmental Abnormalities in the Pathogenesis of Juvenile Myoclonic Epilepsy. Front Cell Neurosci 2019; 13:433. [PMID: 31611775 PMCID: PMC6776584 DOI: 10.3389/fncel.2019.00433] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 09/09/2019] [Indexed: 12/17/2022] Open
Abstract
Juvenile myoclonic epilepsy (JME), a lifelong disorder that starts during adolescence, is the most common of genetic generalized epilepsy syndromes. JME is characterized by awakening myoclonic jerks and myoclonic-tonic-clonic (m-t-c) grand mal convulsions. Unfortunately, one third of JME patients have drug refractory m-t-c convulsions and these recur in 70-80% who attempt to stop antiepileptic drugs (AEDs). Behavioral studies documented impulsivity, but also impairment of executive functions relying on organization and feedback, which points to prefrontal lobe dysfunction. Quantitative voxel-based morphometry (VBM) revealed abnormalities of gray matter (GM) volumes in cortical (frontal and parietal) and subcortical structures (thalamus, putamen, and hippocampus). Proton magnetic resonance spectroscopy (MRS) found evidence of dysfunction of thalamic neurons. White matter (WM) integrity was disrupted in corpus callosum and frontal WM tracts. Magnetic resonance imaging (MRI) further unveiled anomalies in both GM and WM structures that were already present at the time of seizure onset. Aberrant growth trajectories of brain development occurred during the first 2 years of JME diagnosis. Because of genetic origin, disease causing variants were sought, first by positional cloning, and most recently, by next generation sequencing. To date, only six genes harboring pathogenic variants (GABRA1, GABRD, EFHC1, BRD2, CASR, and ICK) with Mendelian and complex inheritance and covering a limited proportion of the world population, are considered as major susceptibility alleles for JME. Evidence on the cellular role, developmental and cell-type expression profiles of these six diverse JME genes, point to their pathogenic variants driving the first steps of brain development when cell division, expansion, axial, and tangential migration of progenitor cells (including interneuron cortical progenitors) sculpture subtle alterations in brain networks and microcircuits during development. These alterations may explain "microdysgenesis" neuropathology, impulsivity, executive dysfunctions, EEG polyspike waves, and awakening m-t-c convulsions observed in JME patients.
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Affiliation(s)
- Maxime Gilsoul
- GIGA-Stem Cells, University of Liège, Liège, Belgium
- GIGA-Neurosciences, University of Liège, Liège, Belgium
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Thierry Grisar
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Antonio V. Delgado-Escueta
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- Epilepsy Genetics/Genomics Lab, Neurology and Research Services, VA Greater Los Angeles Healthcare System, Los Angeles, CA, United States
| | - Laurence de Nijs
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
- School for Mental Health and Neuroscience, Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands
| | - Bernard Lakaye
- GIGA-Stem Cells, University of Liège, Liège, Belgium
- GIGA-Neurosciences, University of Liège, Liège, Belgium
- GENESS International Consortium, Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
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Peripapillary retinal nerve fibre layer thinning in genetic generalized epilepsy. Seizure 2019; 71:201-206. [PMID: 31386963 DOI: 10.1016/j.seizure.2019.07.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 07/24/2019] [Accepted: 07/25/2019] [Indexed: 12/27/2022] Open
Abstract
PURPOSE The purpose of this study was to compare the peripapillary retinal nerve fibre layer (RNFL) between patients with genetic generalized epilepsy (GGE) and healthy controls. METHODS This prospective observational study was conducted on adults aged 18-60 years. The study group comprised 26 consecutive patients who met the inclusion criteria and 26 healthy age- and sex-matched healthy adults. Peripapillary RNFL thickness was measured by spectral domain optical coherence tomography. RESULTS The average peripapillary RNFL thickness was significantly thinner for GGE patients (98.61 μm) than for healthy controls (104.77 μm) (p = 0.016). Similar results were obtained for the left eye. The peripapillary RFNL thickness of all quadrants was lower for GGE patients than for healthy controls, but it was significant only in the superior (p = 0.009) and inferior (p = 0.024) quadrants for both eyes. CONCLUSIONS Our results suggest that the peripapillary RNFL is significantly thinner in GGE patients than in healthy participants. We concluded that this microstructural feature might be an intrinsic feature of GGE.
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Afawi Z, Gamirova RG, Jaxybayeva AK, Esin RG. Modern achievements in genetic studies of idiopathic generalized epilepsies. Zh Nevrol Psikhiatr Im S S Korsakova 2018; 118:56-60. [DOI: 10.17116/jnevro201811810256] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Wu SZ, Ye H, Yang XG, Lu ZL, Qu Q, Qu J. Case-control pharmacogenetic study of HCN1/HCN2 variants and genetic generalized epilepsies. Clin Exp Pharmacol Physiol 2017; 45:226-233. [PMID: 29047147 DOI: 10.1111/1440-1681.12877] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/06/2017] [Accepted: 10/12/2017] [Indexed: 11/27/2022]
Abstract
Epilepsy is a common complex neurological disorder, and some forms are resistant to drug treatment. The HCN1/HCN2 genes encode hyperpolarization-activated cyclic nucleotide-gated channels, which play important roles in the electrophysiology of neurons. We investigated the association between HCN1/HCN2 variants and drug resistance or the risk of genetic generalized epilepsies (GGEs). We used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to assess nine variants of HCN1/HCN2 in 284 healthy participants and 483 GGEs (279 drug-responsive, 204 drug-resistant). Frequencies of HCN2 rs7255568 and rs3752158 G alleles differed in GGEs and in controls (P = .039, P = .027, respectively). The frequency of HCN2 haplotype (CAC) was higher in patients than controls (P = .046). The frequency of the HCN1 rs10462087 CC+CT genotype was lower in patients with childhood absence epilepsy (CAE) than controls (P = .047). Rs7255568 was associated with the risk of CAE (P = .028) and juvenile myoclonic epilepsy (JME) (P = .02). Rs3752158 was associated with the risk of generalized tonic-clonic seizures, JME, and febrile seizures (all P < .05). The frequency of the HCN2 haplotype (CAC) was higher in patients with JME (P = .015) and in those with febrile seizures (P = .024) than in controls. No significant association was found between HCN1/HCN2 alleles, genotypes or haplotypes, and drug resistance in patients. After Bonferroni's multiple comparisons correction, only the HCN2 rs3752158 C allele and GC+CC genotype frequencies in patients with JME were higher than those in controls (19.2% vs 11.6%, odds ratio (OR) = 1.71, 95% CI = 1.18-2.32), P = .004 < 0.05/9; 36% vs 22.2%, OR = 1.62(1.18-2.23), P = .003 < 0.05/9). Our study suggests that HCN2 rs3752158 is involved in the susceptibility to JME.
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Affiliation(s)
- Shu-Zhi Wu
- Department of Neurology, The Third Clinical Institute Affiliated to Wenzhou Medical University & Wenzhou People's Hospital, Wenzhou, China
| | - Hua Ye
- Department of Neurology, The Third Clinical Institute Affiliated to Wenzhou Medical University & Wenzhou People's Hospital, Wenzhou, China
| | - Xiao-Guo Yang
- Department of Neurology, The Third Clinical Institute Affiliated to Wenzhou Medical University & Wenzhou People's Hospital, Wenzhou, China
| | - Zhi-Li Lu
- Department of Pathology, Hunan Cancer Hospital, Central South University, Changsha, China
| | - Qiang Qu
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - Jian Qu
- Department of Pharmacy, The Second Xiangya Hospital, Central South University, Changsha, China.,Institute of Clinical Pharmacy, Central South University, Changsha, China
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12
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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.
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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
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13
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Raju PK, Satishchandra P, Nayak S, Iyer V, Sinha S, Anand A. Microtubule-associated defects caused by EFHC1
mutations in juvenile myoclonic epilepsy. Hum Mutat 2017; 38:816-826. [DOI: 10.1002/humu.23221] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 03/21/2017] [Accepted: 03/21/2017] [Indexed: 01/06/2023]
Affiliation(s)
- Praveen K Raju
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research; Jakkur Bangalore Karnataka India
| | | | - Sourav Nayak
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research; Jakkur Bangalore Karnataka India
| | - Vishwanathan Iyer
- Department of Neurology; National Institute of Mental Health and Neurosciences; Bangalore Karnataka India
| | - Sanjib Sinha
- Department of Neurology; National Institute of Mental Health and Neurosciences; Bangalore Karnataka India
| | - Anuranjan Anand
- Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research; Jakkur Bangalore Karnataka India
- Neuroscience Unit; Jawaharlal Nehru Centre for Advanced Scientific Research; Jakkur Bangalore Karnataka India
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14
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Rezazadeh A, Borlot F, Faghfoury H, Andrade DM. Genetic generalized epilepsy in three siblings with 8q21.13-q22.2 duplication. Seizure 2017; 48:57-61. [DOI: 10.1016/j.seizure.2017.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 04/05/2017] [Indexed: 12/24/2022] Open
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15
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Thounaojam R, Langbang L, Itisham K, Sobhani R, Srivastava S, Ramanujam B, Verma R, Tripathi M, Aguan K. EFHC1 mutation in Indian juvenile myoclonic epilepsy patient. Epilepsia Open 2017; 2:84-89. [PMID: 29750216 PMCID: PMC5939392 DOI: 10.1002/epi4.12037] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/12/2016] [Indexed: 12/21/2022] Open
Abstract
Objective Juvenile myoclonic epilepsy (JME) is the most common form of idiopathic generalized epilepsies (IGEs) and is genetically heterogeneous. Mutations in EFHC1 cause JME. Because about 2 million people in India are affected by JME alone, we investigated the prevalence of mutations in the EFHC1 gene in the Indian population with JME. We studied 63 patients with JME and 80 healthy controls. Methods Clinical identification of JME was evaluated using established criteria. Following clinical evaluation of the patients and confirming presence of JME, blood samples were collected from each patient and healthy individual. Subsequently, genomic DNA was extracted from the blood samples. Eleven exons of the EFHC1 gene were individually amplified by polymerase chain reaction (PCR) for each DNA sample. The PCR products were then purified and sequenced commercially. The identified DNA variants were sequenced at least twice in both the forward and reverse directions and compared with the Exome Aggregation Consortium (ExAC) database. Results We found five heterozygous and one homozygous variant. We found three novel coding variants 661C→T, 779 G →A, and 730 C→T, which lead to R221C, R260Q, and R244STOP amino acid substitutions, respectively. The coding variant 475 C→T, resulting in the amino acid substitution R159W, reported earlier as polymorphism, was also identified in both patient and control populations. Significance Detection of these three novel variants, excluding R159W, which is considered polymorphism, expands the range of possible mutations in the EFHC1 gene. The novel variants that we are reporting herein have not been mentioned before as occurring in JME patients of other ethnic population. Therefore, these novel coding variants may be confined to the Indian JME population. Further studies on the mutational spectrum of EFHC1 in a larger number of Indian JME patients concurrent with their mode of inheritance and underlying functional assays should establish whether EFHC1 could be a panethnic gene for JME.
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Affiliation(s)
- Romita Thounaojam
- Department of Biotechnology and Bioinformatics North Eastern Hill University (NEHU) Shillong India
| | - Leader Langbang
- Department of Biotechnology and Bioinformatics North Eastern Hill University (NEHU) Shillong India
| | - Kavish Itisham
- Department of Neurology Neurosciences Centre All India Institute of Medical Sciences (AIIMS) New Delhi India
| | - Roohollah Sobhani
- Department of Biotechnology and Bioinformatics North Eastern Hill University (NEHU) Shillong India
| | - Shivani Srivastava
- Department of Neurology Neurosciences Centre All India Institute of Medical Sciences (AIIMS) New Delhi India
| | - Bhargavi Ramanujam
- Department of Neurology Neurosciences Centre All India Institute of Medical Sciences (AIIMS) New Delhi India
| | - Ramesh Verma
- Department of Neurology Neurosciences Centre All India Institute of Medical Sciences (AIIMS) New Delhi India
| | - Manjari Tripathi
- Department of Neurology Neurosciences Centre All India Institute of Medical Sciences (AIIMS) New Delhi India
| | - Kripamoy Aguan
- Department of Biotechnology and Bioinformatics North Eastern Hill University (NEHU) Shillong India
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16
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Tao C, Nichols TE, Hua X, Ching CRK, Rolls ET, Thompson PM, Feng J. Generalized reduced rank latent factor regression for high dimensional tensor fields, and neuroimaging-genetic applications. Neuroimage 2016; 144:35-57. [PMID: 27666385 DOI: 10.1016/j.neuroimage.2016.08.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Revised: 08/01/2016] [Accepted: 08/14/2016] [Indexed: 11/18/2022] Open
Abstract
We propose a generalized reduced rank latent factor regression model (GRRLF) for the analysis of tensor field responses and high dimensional covariates. The model is motivated by the need from imaging-genetic studies to identify genetic variants that are associated with brain imaging phenotypes, often in the form of high dimensional tensor fields. GRRLF identifies from the structure in the data the effective dimensionality of the data, and then jointly performs dimension reduction of the covariates, dynamic identification of latent factors, and nonparametric estimation of both covariate and latent response fields. After accounting for the latent and covariate effects, GRLLF performs a nonparametric test on the remaining factor of interest. GRRLF provides a better factorization of the signals compared with common solutions, and is less susceptible to overfitting because it exploits the effective dimensionality. The generality and the flexibility of GRRLF also allow various statistical models to be handled in a unified framework and solutions can be efficiently computed. Within the field of neuroimaging, it improves the sensitivity for weak signals and is a promising alternative to existing approaches. The operation of the framework is demonstrated with both synthetic datasets and a real-world neuroimaging example in which the effects of a set of genes on the structure of the brain at the voxel level were measured, and the results compared favorably with those from existing approaches.
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Affiliation(s)
- Chenyang Tao
- Centre for Computational Systems Biology and School of Mathematical Sciences, Fudan University, Shanghai, PR China; Department of Computer Science, Warwick University, Coventry, UK
| | | | - Xue Hua
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA
| | - Christopher R K Ching
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Interdepartmental Neuroscience Graduate Program, UCLA School of Medicine, Los Angeles, CA, USA
| | - Edmund T Rolls
- Department of Computer Science, Warwick University, Coventry, UK; Oxford Centre for Computational Neuroscience, Oxford, UK
| | - Paul M Thompson
- Imaging Genetics Center, Institute for Neuroimaging & Informatics, University of Southern California, Los Angeles, CA, USA; Departments of Neurology, Psychiatry, Radiology, Engineering, Pediatrics, and Ophthalmology, USC, Los Angeles, CA, USA
| | - Jianfeng Feng
- Centre for Computational Systems Biology and School of Mathematical Sciences, Fudan University, Shanghai, PR China; Department of Computer Science, Warwick University, Coventry, UK; School of Life Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200433, PR China.
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17
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Wade E, Daniel P, Jenkins Z, McInerney-Leo A, Leo P, Morgan T, Addor M, Adès L, Bertola D, Bohring A, Carter E, Cho TJ, Duba HC, Fletcher E, Kim C, Krakow D, Morava E, Neuhann T, Superti-Furga A, Veenstra-Knol I, Wieczorek D, Wilson L, Hennekam R, Sutherland-Smith A, Strom T, Wilkie A, Brown M, Duncan E, Markie D, Robertson S. Mutations in MAP3K7 that Alter the Activity of the TAK1 Signaling Complex Cause Frontometaphyseal Dysplasia. Am J Hum Genet 2016; 99:392-406. [PMID: 27426733 DOI: 10.1016/j.ajhg.2016.05.024] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/22/2016] [Indexed: 12/29/2022] Open
Abstract
Frontometaphyseal dysplasia (FMD) is a progressive sclerosing skeletal dysplasia affecting the long bones and skull. The cause of FMD in some individuals is gain-of-function mutations in FLNA, although how these mutations result in a hyperostotic phenotype remains unknown. Approximately one half of individuals with FMD have no identified mutation in FLNA and are phenotypically very similar to individuals with FLNA mutations, except for an increased tendency to form keloid scars. Using whole-exome sequencing and targeted Sanger sequencing in 19 FMD-affected individuals with no identifiable FLNA mutation, we identified mutations in two genes-MAP3K7, encoding transforming growth factor β (TGF-β)-activated kinase (TAK1), and TAB2, encoding TAK1-associated binding protein 2 (TAB2). Four mutations were found in MAP3K7, including one highly recurrent (n = 15) de novo mutation (c.1454C>T [ p.Pro485Leu]) proximal to the coiled-coil domain of TAK1 and three missense mutations affecting the kinase domain (c.208G>C [p.Glu70Gln], c.299T>A [p.Val100Glu], and c.502G>C [p.Gly168Arg]). Notably, the subjects with the latter three mutations had a milder FMD phenotype. An additional de novo mutation was found in TAB2 (c.1705G>A, p.Glu569Lys). The recurrent mutation does not destabilize TAK1, or impair its ability to homodimerize or bind TAB2, but it does increase TAK1 autophosphorylation and alter the activity of more than one signaling pathway regulated by the TAK1 kinase complex. These findings show that dysregulation of the TAK1 complex produces a close phenocopy of FMD caused by FLNA mutations. Furthermore, they suggest that the pathogenesis of some of the filaminopathies caused by FLNA mutations might be mediated by misregulation of signaling coordinated through the TAK1 signaling complex.
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18
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EFHC1 variants in juvenile myoclonic epilepsy: reanalysis according to NHGRI and ACMG guidelines for assigning disease causality. Genet Med 2016; 19:144-156. [PMID: 27467453 DOI: 10.1038/gim.2016.86] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 05/09/2016] [Indexed: 12/12/2022] Open
Abstract
PURPOSE EFHC1 variants are the most common mutations in inherited myoclonic and grand mal clonic-tonic-clonic (CTC) convulsions of juvenile myoclonic epilepsy (JME). We reanalyzed 54 EFHC1 variants associated with epilepsy from 17 cohorts based on National Human Genome Research Institute (NHGRI) and American College of Medical Genetics and Genomics (ACMG) guidelines for interpretation of sequence variants. METHODS We calculated Bayesian LOD scores for variants in coinheritance, unconditional exact tests and odds ratios (OR) in case-control associations, allele frequencies in genome databases, and predictions for conservation/pathogenicity. We reviewed whether variants damage EFHC1 functions, whether efhc1-/- KO mice recapitulate CTC convulsions and "microdysgenesis" neuropathology, and whether supernumerary synaptic and dendritic phenotypes can be rescued in the fly model when EFHC1 is overexpressed. We rated strengths of evidence and applied ACMG combinatorial criteria for classifying variants. RESULTS Nine variants were classified as "pathogenic," 14 as "likely pathogenic," 9 as "benign," and 2 as "likely benign." Twenty variants of unknown significance had an insufficient number of ancestry-matched controls, but ORs exceeded 5 when compared with racial/ethnic-matched Exome Aggregation Consortium (ExAC) controls. CONCLUSIONS NHGRI gene-level evidence and variant-level evidence establish EFHC1 as the first non-ion channel microtubule-associated protein whose mutations disturb R-type VDCC and TRPM2 calcium currents in overgrown synapses and dendrites within abnormally migrated dislocated neurons, thus explaining CTC convulsions and "microdysgenesis" neuropathology of JME.Genet Med 19 2, 144-156.
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19
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Wight JE, Nguyen V, Medina MT, Patterson C, Durón RM, Molina Y, Lin Y, Martínez‐Juárez IE, Ochoa A, Jara‐Prado A, Tanaka M, Bai D, Aftab S, Bailey JN, Delgado‐Escueta AV. Chromosome loci vary by juvenile myoclonic epilepsy subsyndromes: linkage and haplotype analysis applied to epilepsy and EEG 3.5-6.0 Hz polyspike waves. Mol Genet Genomic Med 2016; 4:197-210. [PMID: 27066514 PMCID: PMC4799870 DOI: 10.1002/mgg3.195] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 11/09/2015] [Accepted: 11/12/2015] [Indexed: 12/15/2022] Open
Abstract
Juvenile myoclonic epilepsy (JME), the most common genetic epilepsy, remains enigmatic because it is considered one disease instead of several diseases. We ascertained three large multigenerational/multiplex JME pedigrees from Honduras with differing JME subsyndromes, including Childhood Absence Epilepsy evolving to JME (CAE/JME; pedigree 1), JME with adolescent onset pyknoleptic absence (JME/pA; pedigree 2), and classic JME (cJME; pedigree 3). All phenotypes were validated, including symptomatic persons with various epilepsies, asymptomatic persons with EEG 3.5-6.0 Hz polyspike waves, and asymptomatic persons with normal EEGs. Two-point parametric linkage analyses were performed with 5185 single-nucleotide polymorphisms on individual pedigrees and pooled pedigrees using four diagnostic models based on epilepsy/EEG diagnoses. Haplotype analyses of the entire genome were also performed for each individual. In pedigree 1, haplotyping identified a 34 cM region in 2q21.2-q31.1 cosegregating with all affected members, an area close to 2q14.3 identified by linkage (Z max = 1.77; pedigree 1). In pedigree 2, linkage and haplotyping identified a 44 cM cosegregating region in 13q13.3-q31.2 (Z max = 3.50 at 13q31.1; pooled pedigrees). In pedigree 3, haplotyping identified a 6 cM cosegregating region in 17q12. Possible cosegregation was also identified in 13q14.2 and 1q32 in pedigree 3, although this could not be definitively confirmed due to the presence of uninformative markers in key individuals. Differing chromosome regions identified in specific JME subsyndromes may contain separate JME disease-causing genes, favoring the concept of JME as several distinct diseases. Whole-exome sequencing will likely identify a CAE/JME gene in 2q21.2-2q31.1, a JME/pA gene in 13q13.3-q31.2, and a cJME gene in 17q12.
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Affiliation(s)
- Jenny E. Wight
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
| | - Viet‐Huong Nguyen
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
| | - Marco T. Medina
- GENESS International ConsortiumLos AngelesCalifornia
- National Autonomous University of HondurasTegucigalpaHonduras
| | - Christopher Patterson
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
| | - Reyna M. Durón
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
- National Autonomous University of HondurasTegucigalpaHonduras
- Universidad Tecnológica Centroamericana (UNITEC)TegucigalpaHonduras
- Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Yolly Molina
- GENESS International ConsortiumLos AngelesCalifornia
- National Autonomous University of HondurasTegucigalpaHonduras
| | - Yu‐Chen Lin
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
| | - Iris E. Martínez‐Juárez
- GENESS International ConsortiumLos AngelesCalifornia
- National Institute of Neurology and NeurosurgeryMexico CityMexico
| | - Adriana Ochoa
- GENESS International ConsortiumLos AngelesCalifornia
- National Institute of Neurology and NeurosurgeryMexico CityMexico
| | - Aurelio Jara‐Prado
- GENESS International ConsortiumLos AngelesCalifornia
- National Institute of Neurology and NeurosurgeryMexico CityMexico
| | - Miyabi Tanaka
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
- Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Dongsheng Bai
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
- Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Sumaya Aftab
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
- Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
| | - Julia N. Bailey
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
- Department of EpidemiologyFielding School of Public Health at UCLALos AngelesCalifornia
| | - Antonio V. Delgado‐Escueta
- Epilepsy Genetics/Genomics LaboratoriesVA GLAHS – West Los AngelesLos AngelesCalifornia
- GENESS International ConsortiumLos AngelesCalifornia
- Department of NeurologyDavid Geffen School of Medicine at UCLALos AngelesCalifornia
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20
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Zhao Y, Shi J, Winey M, Klymkowsky MW. Identifying domains of EFHC1 involved in ciliary localization, ciliogenesis, and the regulation of Wnt signaling. Dev Biol 2016; 411:257-265. [PMID: 26783883 DOI: 10.1016/j.ydbio.2016.01.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 11/16/2015] [Accepted: 01/07/2016] [Indexed: 12/24/2022]
Abstract
EFHC1 encodes a ciliary protein that has been linked to Juvenile Myoclonic Epilepsy. In ectodermal explants, derived from Xenopus laevis embryos, the morpholino-mediated down-regulation of EFHC1b inhibited multiciliated cell formation. In those ciliated cells that did form, axoneme but not basal body formation was inhibited. EFHC1b morphant embryos displayed defects in central nervous system (CNS) and neural crest patterning that were rescued by a EFHC1b-GFP chimera. EFHC1b-GFP localized to ciliary axonemes in epidermal, gastrocoele roof plate, and neural tube cells. In X. laevis there is a link between Wnt signaling and multiciliated cell formation. While down-regulation of EFHC1b led to a ~2-fold increase in the activity of the β-catenin/Wnt-responsive TOPFLASH reporter, EFHC1b-GFP did not inhibit β-catenin activation of TOPFLASH. Wnt8a RNA levels were increased in EFHC1b morphant ectodermal explants and intact embryos, analyzed prior to the on-set of ciliogenesis. Rescue of the EFHC1b MO's ciliary axonemal phenotypes required the entire protein; in contrast, the EFHC1b morpholino's Wnt8a, CNS, and neural crest phenotypes were rescued by a truncated form of EFHC1b. The EFHC1b morpholino's Wnt8a phenotype was also rescued by the injection of RNAs encoding secreted Wnt inhibitors, suggesting that these phenotypes are due to effects on Wnt signaling, rather than the loss of cilia, an observation of potential relevance to understanding EFHC1's role in human neural development.
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Affiliation(s)
- Ying Zhao
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA
| | - Jianli Shi
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA
| | - Mark Winey
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA
| | - Michael W Klymkowsky
- Molecular, Cellular & Developmental Biology, University of Colorado Boulder Boulder, Colorado 80309-0347, USA.
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Meta-analysis identifies seven susceptibility loci involved in the atopic march. Nat Commun 2015; 6:8804. [PMID: 26542096 PMCID: PMC4667629 DOI: 10.1038/ncomms9804] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 10/06/2015] [Indexed: 12/20/2022] Open
Abstract
Eczema often precedes the development of asthma in a disease course called the ‘atopic march'. To unravel the genes underlying this characteristic pattern of allergic disease, we conduct a multi-stage genome-wide association study on infantile eczema followed by childhood asthma in 12 populations including 2,428 cases and 17,034 controls. Here we report two novel loci specific for the combined eczema plus asthma phenotype, which are associated with allergic disease for the first time; rs9357733 located in EFHC1 on chromosome 6p12.3 (OR 1.27; P=2.1 × 10−8) and rs993226 between TMTC2 and SLC6A15 on chromosome 12q21.3 (OR 1.58; P=5.3 × 10−9). Additional susceptibility loci identified at genome-wide significance are FLG (1q21.3), IL4/KIF3A (5q31.1), AP5B1/OVOL1 (11q13.1), C11orf30/LRRC32 (11q13.5) and IKZF3 (17q21). We show that predominantly eczema loci increase the risk for the atopic march. Our findings suggest that eczema may play an important role in the development of asthma after eczema. The development of asthma following eczema is known as the atopic march. Here the authors conduct a GWAS on affected children and identify two novel loci associated with the disease phenotype.
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Lesca G, Depienne C. Epilepsy genetics: the ongoing revolution. Rev Neurol (Paris) 2015; 171:539-57. [PMID: 26003806 DOI: 10.1016/j.neurol.2015.01.569] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/24/2014] [Accepted: 01/20/2015] [Indexed: 01/04/2023]
Abstract
Epilepsies have long remained refractory to gene identification due to several obstacles, including a highly variable inter- and intrafamilial expressivity of the phenotypes, a high frequency of phenocopies, and a huge genetic heterogeneity. Recent technological breakthroughs, such as array comparative genomic hybridization and next generation sequencing, have been leading, in the past few years, to the identification of an increasing number of genomic regions and genes in which mutations or copy-number variations cause various epileptic disorders, revealing an enormous diversity of pathophysiological mechanisms. The field that has undergone the most striking revolution is that of epileptic encephalopathies, for which most of causing genes have been discovered since the year 2012. Some examples are the continuous spike-and-waves during slow-wave sleep and Landau-Kleffner syndromes for which the recent discovery of the role of GRIN2A mutations has finally confirmed the genetic bases. These new technologies begin to be used for diagnostic applications, and the main challenge now resides in the interpretation of the huge mass of variants detected by these methods. The identification of causative mutations in epilepsies provides definitive confirmation of the clinical diagnosis, allows accurate genetic counselling, and sometimes permits the development of new appropriate and specific antiepileptic therapies. Future challenges include the identification of the genetic or environmental factors that modify the epileptic phenotypes caused by mutations in a given gene and the understanding of the role of somatic mutations in sporadic epilepsies.
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Affiliation(s)
- G Lesca
- Service de génétique, groupement hospitalier Est, hospices civils de Lyon, 59, boulevard Pinel, 69677 Bron, France; Université Claude-Bernard Lyon 1, 43, boulevard du 11-Novembre-1918, 69100 Villeurbanne, France; CRNL, CNRS UMR 5292, Inserm U1028, bâtiment IMBL, 11, avenue Jean-Capelle, 69621 Villeurbanne cedex, France.
| | - C Depienne
- Département de génétique et cytogénétique, hôpital Pitié-Salpêtrière, AP-HP, 47-83, boulevard de l'Hôpital, 75651 Paris cedex 13, France; Sorbonne universités, UPMC université Paris 06, 4, place Jussieu, 75005 Paris, France; ICM, CNRS UMR 7225, Inserm U1127, 47, boulevard de l'Hôpital, 75651 Paris cedex 13, France
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Sapio MR, Vessaz M, Thomas P, Genton P, Fricker LD, Salzmann A. Novel carboxypeptidase A6 (CPA6) mutations identified in patients with juvenile myoclonic and generalized epilepsy. PLoS One 2015; 10:e0123180. [PMID: 25875328 PMCID: PMC4395397 DOI: 10.1371/journal.pone.0123180] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 02/17/2015] [Indexed: 01/12/2023] Open
Abstract
Carboxypeptidase A6 (CPA6) is a peptidase that removes C-terminal hydrophobic amino acids from peptides and proteins. The CPA6 gene is expressed in the brains of humans and animals, with high levels of expression during development. It is translated with a prodomain (as proCPA6), which is removed before secretion. The active form of CPA6 binds tightly to the extracellular matrix (ECM) where it is thought to function in the processing of peptides and proteins. Mutations in the CPA6 gene have been identified in patients with temporal lobe epilepsy and febrile seizures. In the present study, we screened for CPA6 mutations in patients with juvenile myoclonic epilepsy and identified two novel missense mutations: Arg36His and Asn271Ser. Patients harboring these mutations also presented with generalized epilepsy. Neither of the novel mutations was found in a control population. Asn271 is highly conserved in CPA6 and other related metallocarboxypeptidases. Arg36 is present in the prodomain and is not highly conserved. To assess structural consequences of the amino acid substitutions, both mutants were modeled within the predicted structure of the enzyme. To examine the effects of these mutations on enzyme expression and activity, we expressed the mutated enzymes in human embryonic kidney 293T cells. These analyses revealed that Asn271Ser abolished enzymatic activity, while Arg36His led to a ~50% reduction in CPA6 levels in the ECM. Pulse-chase using radio-labeled amino acids was performed to follow secretion. Newly-synthesized CPA6 appeared in the ECM with peak levels between 2-8 hours. There was no major difference in time course between wild-type and mutant forms, although the amount of radiolabeled CPA6 in the ECM was lower for the mutants. Our experiments demonstrate that these mutations in CPA6 are deleterious and provide further evidence for the involvement of CPA6 mutations in the predisposition for several types of epilepsy.
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Affiliation(s)
- Matthew R. Sapio
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States of America
| | - Monique Vessaz
- Department of Genetic Medicine and Laboratory, University Hospitals of Geneva, Geneva, Switzerland
| | - Pierre Thomas
- Department of Neurology, University Hospital, Nice, France
| | - Pierre Genton
- Centre Saint Paul, Hôpital Henri Gastaut, Marseille, France
| | - Lloyd D. Fricker
- Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States of America
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, United States of America
- * E-mail: (LDF); (AS)
| | - Annick Salzmann
- Department of Psychiatry, University of Geneva, Geneva, Switzerland
- * E-mail: (LDF); (AS)
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von Podewils F, Kowoll V, Schroeder W, Geithner J, Wang ZI, Gaida B, Bombach P, Kessler C, Felbor U, Runge U. Predictive value of EFHC1 variants for the long-term seizure outcome in juvenile myoclonic epilepsy. Epilepsy Behav 2015; 44:61-6. [PMID: 25625532 DOI: 10.1016/j.yebeh.2014.12.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 12/12/2014] [Accepted: 12/13/2014] [Indexed: 11/30/2022]
Abstract
OBJECTIVE This study aimed to determine the contribution of EFHC1 variants to the phenotypic variability of juvenile myoclonic epilepsy (JME) and to evaluate their diagnostic value regarding previously identified clinical long-term seizure outcome predictors in a consecutive cohort of patients with JME. METHODS Thirty-eight probands and three family members affected with JME were studied at a tertiary epilepsy center with a review of their medical records and a subsequent face-to-face interview. All coding EFHC1 exons and adjacent exon/intron boundaries were directly sequenced. RESULTS The previously reported EFHC1 mutation F229L was found in two cases who presented with early generalized tonic-clonic seizure (GTCS) onset and appeared to be associated with milder subtypes of JME. Variant R294H was identified in two further probands who had a subtype of JME developing from childhood absence epilepsy. However, segregation of the phenotype with this variant could not be confirmed in one family. CONCLUSIONS Our findings corroborate the heterogeneity of JME as an electroclinical epilepsy syndrome and provide evidence that genetic factors may influence and help predict the long-term seizure outcome in patients with JME.
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Affiliation(s)
- Felix von Podewils
- Department of Neurology, Epilepsy Center, University of Greifswald, Greifswald, Germany.
| | - Victoria Kowoll
- Department of Neurology, Epilepsy Center, University of Greifswald, Greifswald, Germany
| | - Winnie Schroeder
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, Ernst Moritz Arndt University, Greifswald, Germany
| | - Julia Geithner
- Department of Neurology, Epilepsy Center, University of Greifswald, Greifswald, Germany; Epilepsy Center Berlin-Brandenburg, Berlin, Germany
| | - Zhong I Wang
- Epilepsy Center, Neurological Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Bernadette Gaida
- Department of Neurology, Epilepsy Center, University of Greifswald, Greifswald, Germany
| | - Paula Bombach
- Department of Neurology, Epilepsy Center, University of Greifswald, Greifswald, Germany
| | - Christof Kessler
- Department of Neurology, Epilepsy Center, University of Greifswald, Greifswald, Germany
| | - Ute Felbor
- Department of Human Genetics, University Medicine Greifswald and Interfaculty Institute of Genetics and Functional Genomics, Ernst Moritz Arndt University, Greifswald, Germany
| | - Uwe Runge
- Department of Neurology, Epilepsy Center, University of Greifswald, Greifswald, Germany
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Subaran RL, Conte JM, Stewart WCL, Greenberg DA. Pathogenic EFHC1 mutations are tolerated in healthy individuals dependent on reported ancestry. Epilepsia 2014; 56:188-94. [PMID: 25489633 PMCID: PMC4354299 DOI: 10.1111/epi.12864] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/08/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Screening for specific coding mutations in the EFHC1 gene has been proposed as a means of assessing susceptibility to juvenile myoclonic epilepsy (JME). To clarify the role of these mutations, especially those reported to be highly penetrant, we sought to measure the frequency of exonic EFHC1 mutations across multiple population samples. METHODS To find and test variants of large effect, we sequenced all EFHC1 exons in 23 JME and 23 non-JME idiopathic generalized epilepsy (IGE) Hispanic patients, and 60 matched controls. We also genotyped specific EFHC1 variants in IGE cases and controls from multiple ethnic backgrounds, including 17 African American IGE patients, with 24 matched controls, and 92 Caucasian JME patients with 103 matched controls. These variants are reported to be pathogenic, but are also found among unphenotyped individuals in public databases. All subjects were from the New York City metro area and all controls were required to have no family history of seizures. RESULTS We found the reportedly pathogenic EFHC1 P77T-R221H (rs149055334-rs79761183) JME haplotype in one Hispanic control and in two African American controls. Public databases also show that the EFHC1 P77T-R221H JME haplotype is present in unphenotyped West African ancestry populations, and we show that it can be found at appreciable frequency in healthy individuals with no family history of epilepsy. We also found a novel splice-site mutation in a single Hispanic JME patient, the effect of which is unknown. SIGNIFICANCE Our findings raise questions about the effect of reportedly pathogenic EFHC1 mutations on JME. One intriguing possibility is that some EFHC1 mutations may be pathogenic only when introduced into specific genetic backgrounds. By focusing on data from multiple populations, including the understudied Hispanic and Black/African American populations, our study highlights that for complex traits like JME, the body of evidence necessary to infer causality is high.
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Affiliation(s)
- Ryan L Subaran
- Nationwide Children's Hospital Research Institute, The Ohio State University, Columbus, Ohio, U.S.A
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Kaneko S, Yoshida S, Kanai K, Yasui-Furukori N, Iwasa H. Development of individualized medicine for epilepsy based on genetic information. Expert Rev Clin Pharmacol 2014; 1:661-81. [DOI: 10.1586/17512433.1.5.661] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Deng H, Xiu X, Song Z. The molecular biology of genetic-based epilepsies. Mol Neurobiol 2013; 49:352-67. [PMID: 23934645 DOI: 10.1007/s12035-013-8523-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 07/24/2013] [Indexed: 01/02/2023]
Abstract
Epilepsy is one of the most common neurological disorders characterized by abnormal electrical activity in the central nervous system. The clinical features of this disorder are recurrent seizures, difference in age onset, type, and frequency, leading to motor, sensory, cognitive, psychic, or autonomic disturbances. Since the discovery of the first monogenic gene mutation in 1995, it is proposed that genetic factor plays an important role in the mechanism of epilepsy. Genes discovered in idiopathic epilepsies encode for ion channel or neurotransmitter receptor proteins, whereas syndromes with epilepsy as a main feature are caused by genes that are involved in functions such as cortical development, mitochondrial function, and cell metabolism. The identification of these monogenic epilepsy-causing genes provides new insight into the pathogenesis of epilepsies. Although most of the identified gene mutations present a monogenic inheritance, most of idiopathic epilepsies are complex genetic diseases exhibiting a polygenic or oligogenic inheritance. This article reviews recent genetic and molecular progresses in exploring the pathogenesis of epilepsy, with special emphasis on monogenic epilepsy-causing genes, including voltage-gated channels (Na(+), K(+), Ca(2+), Cl(-), and HCN), ligand-gated channels (nicotinic acetylcholine and GABAA receptors), non-ion channel genes as well as the mitochondrial DNA genes. These progresses have improved our understanding of the complex neurological disorder.
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Affiliation(s)
- Hao Deng
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, Tongzipo Road 138, Changsha, Hunan, 410013, People's Republic of China,
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Yamakawa K, Suzuki T. Re-evaluation of myoclonin1 immunosignals in neuron, mitotic spindle, and midbody--nonspecific? Epilepsy Behav 2013; 28 Suppl 1:S61-2. [PMID: 23756482 DOI: 10.1016/j.yebeh.2012.06.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 06/30/2012] [Indexed: 11/16/2022]
Abstract
Mutations in EFHC1 gene cause juvenile myoclonic epilepsy (JME). We previously showed that myoclonin1 protein encoded by EFHC1 is expressed in prenatal choroid plexus and postnatal ependymal cell cilia but may not be in neurons. However, another group reported that myoclonin1 is expressed in neurons and at mitotic spindle, and that the suppression of EFHC1 by RNAi caused disruption of mitotic spindle structure, impaired M-phase progression, and an increase of apoptosis. We re-investigated their results by using the same polyclonal antibody that they used, and found that the signals in neurons remained in Efhc1-deficient mouse, suggesting that the signals in neurons were nonspecific. Furthermore, Efhc1 (-/-) mouse did not show any abnormalities such as disruption of mitotic spindle structure, impaired M-phase progression, and an increase of apoptosis. Further investigations are required to clarify these discrepancies.
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Affiliation(s)
- Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Brain Science Institute (BSI), 2-1 Hirosawa, Wako-shi, Saitama, Japan.
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Abstract
In the International League Against Epilepsy's most recent revision of classification and terminology, the term idiopathic epilepsy, previously used to describe those epilepsies whose cause was unknown, but presumed genetic, has been removed. It has been replaced by the term genetic epilepsy, only to be used to describe epilepsy in which the etiology has a known or presumed genetic defect in which seizures are the core symptom of the disorder. The purpose of this article was to review the electroclinical spectrum of those epilepsies that would fall under this new designation of genetic epilepsies in the context of specific generalized epilepsy syndromes providing an update in the clinical, electroencephalographic, and genetic findings in these syndromes.
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Wagnon JL, Briese M, Sun W, Mahaffey CL, Curk T, Rot G, Ule J, Frankel WN. CELF4 regulates translation and local abundance of a vast set of mRNAs, including genes associated with regulation of synaptic function. PLoS Genet 2012; 8:e1003067. [PMID: 23209433 PMCID: PMC3510034 DOI: 10.1371/journal.pgen.1003067] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2012] [Accepted: 09/20/2012] [Indexed: 11/25/2022] Open
Abstract
RNA–binding proteins have emerged as causal agents of complex neurological diseases. Mice deficient for neuronal RNA–binding protein CELF4 have a complex neurological disorder with epilepsy as a prominent feature. Human CELF4 has recently been associated with clinical features similar to those seen in mutant mice. CELF4 is expressed primarily in excitatory neurons, including large pyramidal cells of the cerebral cortex and hippocampus, and it regulates excitatory but not inhibitory neurotransmission. We examined mechanisms underlying neuronal hyperexcitability in Celf4 mutants by identifying CELF4 target mRNAs and assessing their fate in the absence of CELF4 in view of their known functions. CELF4 binds to at least 15%–20% of the transcriptome, with striking specificity for the mRNA 3′ untranslated region. CELF4 mRNA targets encode a variety of proteins, many of which are well established in neuron development and function. While the overall abundance of these mRNA targets is often dysregulated in Celf4 deficient mice, the actual expression changes are modest at the steady-state level. In contrast, by examining the transcriptome of polysome fractions and the mRNA distribution along the neuronal cell body-neuropil axis, we found that CELF4 is critical for maintaining mRNA stability and availability for translation. Among biological processes associated with CELF4 targets that accumulate in neuropil of mutants, regulation of synaptic plasticity and transmission are the most prominent. Together with a related study of the impact of CELF4 loss on sodium channel Nav1.6 function, we suggest that CELF4 deficiency leads to abnormal neuronal function by combining a specific effect on neuronal excitation with a general impairment of synaptic transmission. These results also expand our understanding of the vital roles RNA–binding proteins play in regulating and shaping the activity of neural circuits. Epilepsy is a devastating brain disorder whereby a loss of regulation of electrochemical signals between neurons causes too much excitation and ultimately results in an “electrical storm” known as a seizure. Epilepsy can be heritable, but it is usually genetically complex, resulting from a collaboration of many genes. It is also a frequent feature of other common brain diseases, such as autism spectrum disorder and intellectual disability, likely because these diseases have a similar dysregulation of neuronal communication. To understand more about how the brain regulates electrical activity, we focused on an RNA–binding protein called CELF4, because a) mice that lack CELF4 have a complex form of epilepsy that includes features of other neurological diseases and b) this kind of protein has the potential to be a master regulator. We show that CELF4 binds to a vast array of mRNAs, and without CELF4 these mRNAs accumulate in the wrong places and can produce the wrong amount of protein. Moreover, many of these mRNAs encode key players in electrochemical signaling between neurons. Although the defects in individual mRNAs are modest, like a genetically complex disease, together these alterations collude to cause neurological symptoms including recurrent seizures.
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Affiliation(s)
- Jacy L. Wagnon
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Michael Briese
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Wenzhi Sun
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
| | | | - Tomaž Curk
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia
| | - Gregor Rot
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia
| | - Jernej Ule
- MRC Laboratory of Molecular Biology, Cambridge, United Kingdom
| | - Wayne N. Frankel
- The Jackson Laboratory, Bar Harbor, Maine, United States of America
- * E-mail:
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Affiliation(s)
- Ortrud K Steinlein
- School of Medicine, Ludwig-Maximilians University of Munich, Munich, Germany.
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de Nijs L, Wolkoff N, Coumans B, Delgado-Escueta AV, Grisar T, Lakaye B. Mutations of EFHC1, linked to juvenile myoclonic epilepsy, disrupt radial and tangential migrations during brain development. Hum Mol Genet 2012; 21:5106-17. [PMID: 22926142 DOI: 10.1093/hmg/dds356] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Heterozygous mutations in Myoclonin1/EFHC1 cause juvenile myoclonic epilepsy (JME), the most common form of genetic generalized epilepsies, while homozygous F229L mutation is associated with primary intractable epilepsy in infancy. Heterozygous mutations in adolescent JME patients produce subtle malformations of cortical and subcortical architecture, whereas homozygous F229L mutation in infancy induces severe brain pathology and death. However, the underlying pathological mechanisms for these observations remain unknown. We had previously demonstrated that EFHC1 is a microtubule-associated protein (MAP) involved in cell division and radial migration during cerebral corticogenesis. Here, we show that JME mutations, including F229L, do not alter the ability of EFHC1 to colocalize with the centrosome and the mitotic spindle, but act in a dominant-negative manner to impair mitotic spindle organization. We also found that mutants EFHC1 expression disrupted radial and tangential migration by affecting the morphology of radial glia and migrating neurons. These results show how Myoclonin1/EFHC1 mutations disrupt brain development and potentially produce structural brain abnormalities on which epileptogenesis is established.
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Jara-Prado A, Martínez-Juárez IE, Ochoa A, González VM, Fernández-González-Aragón MDC, López-Ruiz M, Medina MT, Bailey JN, Delgado-Escueta AV, Alonso ME. Novel Myoclonin1/EFHC1 mutations in Mexican patients with juvenile myoclonic epilepsy. Seizure 2012; 21:550-4. [PMID: 22727576 DOI: 10.1016/j.seizure.2012.05.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 05/28/2012] [Accepted: 05/29/2012] [Indexed: 11/25/2022] Open
Abstract
PURPOSE The purpose of this study was to identify the prevalence of mutations in the Myoclonin1/EFHC1 gene in Mexican patients with juvenile myoclonic epilepsy (JME). METHOD We studied forty-one patients at the National Institute of Neurology and Neurosurgery in Mexico City and 100 healthy controls. DNA was extracted from the peripheral venous blood of all participants. The exons of EFHC1 were then amplified and sequenced. RESULTS We found three new putative mutations, all of which were heterozygous missense mutations located in exon 3. The first identified mutation, 352C>T, produces a R118C change in the protein and cosegregated in the patient's affected father and brother. The second identified mutation, 544C>T, produces a R182L change in the protein and was found in the patient's asymptomatic father. The third identified mutation, 458>A, produces a R153Q change in the protein and was also found in the patient's father. These mutations were not found in controls. CONCLUSIONS The frequency of Myoclonin1/EFHC1 mutations in our sample is 7.3%. Thus, we conclude that mutations in the Myoclonin1/EFHC1 gene are an important cause of JME in Mexican patients.
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Affiliation(s)
- Aurelio Jara-Prado
- Neurogenetics and Molecular Biology Department, National Institute of Neurology and Neurosurgery of Mexico, Insurgentes Sur 3877, Col. La Fama, Tlalpan, México D.F. 14269, Mexico.
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Berger I, Dor T, Halvardson J, Edvardson S, Shaag A, Feuk L, Elpeleg O. Intractable epilepsy of infancy due to homozygous mutation in the EFHC1 gene. Epilepsia 2012; 53:1436-40. [DOI: 10.1111/j.1528-1167.2012.03536.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Steinlein OK. Ion channel mutations in neuronal diseases: a genetics perspective. Chem Rev 2012; 112:6334-52. [PMID: 22607259 DOI: 10.1021/cr300044d] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ortrud K Steinlein
- Institute of Human Genetics, University Hospital, Ludwig-Maximilians-University , Goethestr. 29, D-80336 Munich, Germany
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Rossetto MG, Zanarella E, Orso G, Scorzeto M, Megighian A, Kumar V, Delgado-Escueta AV, Daga A. Defhc1.1, a homologue of the juvenile myoclonic gene EFHC1, modulates architecture and basal activity of the neuromuscular junction in Drosophila. Hum Mol Genet 2011; 20:4248-57. [PMID: 21835885 DOI: 10.1093/hmg/ddr352] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Mutations in the EFHC1 gene have been linked to juvenile myoclonic epilepsy. To understand EFHC1 function in vivo, we generated knockout Drosophila for the fly homolog Defhc1.1. We found that the neuromuscular junction synapse of Defhc1.1 mutants displays an increased number of satellite boutons resulting in increased spontaneous neurotransmitter release. Defhc1.1 binds to microtubules in vitro and overlaps in vivo with axonal and synaptic microtubules. Elimination of Defhc1.1 from synaptic terminals reduces the number of microtubule loops, suggesting that Defhc1.1 is a negative regulator of microtubule dynamics. In fact, pharmacological treatment of Defhc1.1 mutants with vinblastine, an inhibitor of microtubule dynamics, suppresses the satellite bouton phenotype. Furthermore, Defhc1.1 mutants display overgrowth of the dendritic arbor and Defhc1.1 overexpression reduces dendrite elaboration. These results suggest that Defhc1.1 functions as an inhibitor of neurite growth by finely tuning the microtubule cytoskeleton dynamics and that EFHC1-dependent juvenile myoclonic epilepsy may result from augmented spontaneous neurotransmitter release due to overgrowth of neuronal processes.
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Neubauer B, Hahn A. Genetik der Epilepsien. Monatsschr Kinderheilkd 2011. [DOI: 10.1007/s00112-011-2395-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Leschziner GD, Coffey AJ, Andrew T, Gregorio SP, Dias-Neto E, Calafato M, Bentley DR, Kinton L, Sander JW, Johnson MR. Q8IYL2 is a candidate gene for the familial epilepsy syndrome of Partial Epilepsy with Pericentral Spikes (PEPS). Epilepsy Res 2011; 96:109-15. [PMID: 21658913 DOI: 10.1016/j.eplepsyres.2011.05.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Revised: 05/03/2011] [Accepted: 05/11/2011] [Indexed: 11/26/2022]
Abstract
PURPOSE Partial Epilepsy with Pericentral Spikes (PEPS) is a novel Mendelian idiopathic epilepsy with evidence of linkage to Chromosome 4p15. Our aim was to identify the causative mutation in this epilepsy syndrome. METHODS We re-annotated all 42 genes in the linked chromosomal region and sequenced all genes within the linked interval. All exons, intron-exon boundaries and untranslated regions were sequenced in the original pedigree, and novel changes segregating correctly were subjected to bioinformatic analysis. Quantitative polymerase chain reaction was performed to examine for potential copy number variation (CNV). RESULTS 29 previously undescribed variants correctly segregating with the linked haplotype were identified. Bioinformatic analysis demonstrated that six variants were non-synonymous coding sequence polymorphisms, one of which, in Q8IYL2 (Gly400Ala), was found in neither Caucasian (n=243) and ancestry-matched Brazilian (n=180) control samples, nor subjects from the 1000 Genome Project. No gene duplications or deletions were identified in the linked region. DISCUSSION We postulate that Q8IYL2 is a causative gene for PEPS, after exhaustive resequencing and bioinformatic analysis. The function of this gene is unknown, but it is expressed in brain tissue.
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Affiliation(s)
- Guy D Leschziner
- Division of Neuroscience, Imperial College London, UK; Wellcome Trust Sanger Institute, Cambridge, UK.
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A locus for juvenile myoclonic epilepsy maps to 2q33-q36. Hum Genet 2010; 128:123-30. [PMID: 20467754 DOI: 10.1007/s00439-010-0831-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2009] [Accepted: 04/22/2010] [Indexed: 10/19/2022]
Abstract
We performed a whole genome linkage analysis in a three-generation south Indian family with multiple members affected with juvenile myoclonic epilepsy (JME). The maximum two-point LOD score obtained was 3.32 at recombination fraction (theta) = 0 for D2S2248. The highest multipoint score of 3.59 was observed for the genomic interval between D2S2322 and D2S2228 at the chromosomal region 2q33-q36. Proximal and distal boundaries of the critical genetic interval were defined by D2S116 and D2S2390, respectively. A 24-Mb haplotype was found to co-segregate with JME in the family. While any potentially causative variant in the functional candidate genes, SLC4A3, SLC23A3, SLC11A1 and KCNE4, was not detected, we propose to examine brain-expressed NRP2, MAP2, PAX3, GPR1, TNS1 and DNPEP, and other such positional candidate genes to identify the disease-causing gene for the disorder.
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de Nijs L, Léon C, Nguyen L, Loturco JJ, Delgado-Escueta AV, Grisar T, Lakaye B. EFHC1 interacts with microtubules to regulate cell division and cortical development. Nat Neurosci 2009; 12:1266-74. [PMID: 19734894 DOI: 10.1038/nn.2390] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Accepted: 08/04/2009] [Indexed: 12/29/2022]
Abstract
Mutations in the EFHC1 gene are linked to juvenile myoclonic epilepsy (JME), one of the most frequent forms of idiopathic generalized epilepsies. JME is associated with subtle alterations of cortical and subcortical architecture, but the underlying pathological mechanism remains unknown. We found that EFHC1 is a microtubule-associated protein involved in the regulation of cell division. In vitro, EFHC1 loss of function disrupted mitotic spindle organization, impaired M phase progression, induced microtubule bundling and increased apoptosis. EFHC1 impairment in the rat developing neocortex by ex vivo and in utero electroporation caused a marked disruption of radial migration. We found that this effect was a result of cortical progenitors failing to exit the cell cycle and defects in the radial glia scaffold organization and in the locomotion of postmitotic neurons. Therefore, we propose that EFHC1 is a regulator of cell division and neuronal migration during cortical development and that disruption of its functions leads to JME.
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Bai D, Bailey JN, Durón RM, Alonso ME, Medina MT, Martínez-Juárez IE, Suzuki T, Machado-Salas J, Ramos-Ramírez R, Tanaka M, Ortega RHC, López-Ruiz M, Rasmussen A, Ochoa A, Jara-Prado A, Yamakawa K, Delgado-Escueta AV. DNA variants in coding region of EFHC1: SNPs do not associate with juvenile myoclonic epilepsy. Epilepsia 2009; 50:1184-90. [PMID: 18823326 DOI: 10.1111/j.1528-1167.2008.01762.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE Juvenile myoclonic epilepsy (JME) accounts for 3 to 12% of all epilepsies. In 2004, we identified a mutation-harboring Mendelian gene that encodes a protein with one EF-hand motif (EFHC1) in chromosome 6p12. We observed one doubly heterozygous and three heterozygous missense mutations in EFHC1 segregating as an autosomal dominant gene with 21 affected members of six Hispanic JME families from California and Mexico. In 2006, similar and three novel missense mutations were reported in sporadic and familial Caucasian JME from Italy and Austria. In this study, we asked if coding single nucleotide polymorphisms (SNPs) of EFHC1 also contribute as susceptibility alleles to JME with complex genetics. METHODS We screened using denaturing high-performance liquid chromatography (DHPLC) and then directly sequenced the 11 exons of EFHC1 in 130 unrelated JME probands, their 352 family members, and seven exons of EFHC1 in 400-614 ethnically matched controls. We carried out case-control association studies between 124 unrelated Hispanic JME probands and 552-614 ethnically matched controls using four SNPs, rs3804506, rs3804505, rs1266787, and rs17851770. We also performed family-based association on SNPs rs3804506 and rs3804505 in 84 complete JME families using the Family-Based Association Test (FBAT) program. RESULTS We found no statistically significant differences between JME probands and controls in case-control association and no genetic transmission disequilibria in family-based association for the tested SNPs. In addition, we identified four new DNA variants in the coding region of EFHC1. CONCLUSION The four coding SNPs, rs3804506, rs3804505, rs1266787, and rs17851770, of EFHC1 may not be susceptibility alleles for JME.
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Affiliation(s)
- Dongsheng Bai
- Epilepsy Genetics/Genomics Lab, CEP, UCLA & VA GLAHS, Los Angeles, California 90073, USA
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Abstract
OBJECTIVE This article aimed to review the latest genes associated with idiopathic focal and generalized epilepsies. METHODS PubMed and Entrez Gene searches pertaining to this work was conducted using specific keyword search terms related to genes and various listed subtopics related to idiopathic epilepsy syndromes. RESULTS Mutations in the cholinergic receptor, neuronal nicotinic, alpha2, alpha4 and beta2 subunit genes have been found in autosomal dominant nocturnal frontal lobe epilepsy. Mutations of potassium voltage-gated channel, KQT-like subfamily, members 2 and 3 genes were identified to be responsible for benign familial neonatal seizures. The voltage-gated sodium channel genes and gamma-aminobutyric acid receptor alpha subunit genes may be involved in the pathogenesis of generalized epilepsy with febrile seizure plus. Mutations of gamma-aminobutyric acid receptor alpha1, gamma-aminobutyric acid receptor delta, calcium channel voltage-dependent beta4 subunit and chloride channel 2 gene are associated with juvenile myoclonic epilepsy. In addition, mutations of leucine-rich, glioma-inactivated 1 gene leads to genetic abnormalities of familial lateral temporal lobe epilepsy. EF-hand domain (C-terminal)-containing 1 gene can cause some patterns of juvenile myoclonic and juvenile absence epilepsies. DISCUSSION Genetic factors play an important role in idiopathic epilepsy syndromes. Ion channel genes and some non-ion channel genes contribute to the pathogenesis of idiopathic epilepsies. Based on these findings, genetic diagnosis and new treatment strategies to part of idiopathic epilepsies become possible in the future.
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Affiliation(s)
- Yang Lu
- The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
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Suzuki T, Miyamoto H, Nakahari T, Inoue I, Suemoto T, Jiang B, Hirota Y, Itohara S, Saido TC, Tsumoto T, Sawamoto K, Hensch TK, Delgado-Escueta AV, Yamakawa K. Efhc1 deficiency causes spontaneous myoclonus and increased seizure susceptibility. Hum Mol Genet 2009; 18:1099-109. [PMID: 19147686 DOI: 10.1093/hmg/ddp006] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Mutations in EFHC1 gene have been previously reported in patients with epilepsies, including those with juvenile myoclonic epilepsy. Myoclonin1, also known as mRib72-1, is encoded by the mouse Efhc1 gene. Myoclonin1 is dominantly expressed in embryonic choroid plexus, post-natal ependymal cilia, tracheal cilia and sperm flagella. In this study, we generated viable Efhc1-deficient mice. Most of the mice were normal in outward appearance, and both sexes were found to be fertile. However, the ventricles of the brains were significantly enlarged in the null mutants, but not in the heterozygotes. Although the ciliary structure was found intact, the ciliary beating frequency was significantly reduced in null mutants. In adult stages, both the heterozygous and null mutants developed frequent spontaneous myoclonus. Furthermore, the threshold of seizures induced by pentylenetetrazol was significantly reduced in both heterozygous and null mutants. These observations seem to further suggest that decrease or loss of function of myoclonin1 may be the molecular basis for epilepsies caused by EFHC1 mutations.
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Affiliation(s)
- Toshimitsu Suzuki
- Laboratory for Neurogenetics, RIKEN Brain Science Institute (BSI), Wako-shi, 351-0198 Saitama, Japan
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Mechanisms of human inherited epilepsies. Prog Neurobiol 2009; 87:41-57. [DOI: 10.1016/j.pneurobio.2008.09.016] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2008] [Revised: 08/25/2008] [Accepted: 09/29/2008] [Indexed: 12/19/2022]
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Kinirons P, Verlaan DJ, Dubé MP, Poirier J, Deacon C, Lortie A, Clément JF, Desbiens R, Carmant L, Cieuta-Walti C, Shevell M, Rouleau GA, Cossette P. A novel locus for idiopathic generalized epilepsy in French-Canadian families maps to 10p11. Am J Med Genet A 2008; 146A:578-84. [PMID: 18241056 DOI: 10.1002/ajmg.a.32139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Idiopathic generalized epilepsy (IGE) has evidence of a strong genetic etiology. We conducted genomewide linkage analysis for genes responsible for familial IGE in French-Canadian pedigrees. Twenty families segregating autosomal dominant epilepsy were collected. Four larger IGE families sufficiently powerful for independent linkage analysis were genome-scanned and follow-up fine mapping was performed over regions with LOD scores >3.0. The genotyping of 16 smaller families was carried out at significantly linked loci for supportive linkage analysis and haplotype comparisons. One of the four families provided a significant linkage result at marker D10S1426 on chromosome 10 (two-point LOD score = 3.05, theta = 0, multipoint LOD score = 3.18). Fine mapping revealed a segregating haplotype and key recombination breakpoints, suggesting a candidate gene interval of 6.5 Mb. Multipoint linkage analyses using the additional 16 families yielded a maximum LOD score under heterogeneity of 4.23 (alpha = 0.34) at this locus. Evaluation of recombination breakpoints in these families narrowed the candidate region to 1.7 Mb. Sequencing of the two known genes in this region, NRP1 and PARD3, was negative for mutation. Replication of linkage to this locus in other cohorts of IGE families is essential to characterize the underlying genetic mechanism for the disease.
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Affiliation(s)
- Peter Kinirons
- Centre for the Study of Brain Diseases, University of Montreal, Montreal, Canada
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Suzuki T, Inoue I, Yamagata T, Morita N, Furuichi T, Yamakawa K. Sequential expression of Efhc1/myoclonin1 in choroid plexus and ependymal cell cilia. Biochem Biophys Res Commun 2007; 367:226-33. [PMID: 18164683 DOI: 10.1016/j.bbrc.2007.12.126] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Accepted: 12/19/2007] [Indexed: 11/19/2022]
Abstract
EFHC1 is a gene mutated in patients with idiopathic epilepsies, and encodes the myoclonin1 protein. We here report the distribution of myoclonin1 in mouse. Immunohistochemical analyses revealed that the myoclonin1 first appeared at the roof of hindbrain at embryonic day 10 (E10), and moved on to choroid plexus at E14. At E18, it moved to ventricle walls and disappeared from choroid plexus. From neonatal to adult stages, myoclonin1 was concentrated in the cilia of ependymal cells at ventricle walls. At adult stages, myoclonin1 expression was also observed at tracheal epithelial cilia in lung and at sperm flagella in testis. Specificities of these immunohistochemical signals were verified by using Efhc1-deficient mice as negative controls. Results of Efhc1 mRNA in situ hybridization were also consistent with the immunohistochemical observations. Our findings raise "choroid plexusopathy" or "ciliopathy" as intriguing candidate cascades for the molecular pathology of epilepsies caused by the EFHC1 mutations.
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Affiliation(s)
- Toshimitsu Suzuki
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako-Shi, Saitama 351-0198, Japan
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Abstract
Genetic influences as causal factors in the epilepsies continue to be vigorously investigated, and we review several important studies of genes reported in 2006. To date, mutations in ion channel and neuroreceptor component genes have been reported in the small fraction of cases with clear Mendelian inheritance. These findings confirm that the so-called "channelopathies" are generally inherited as monogenic disorders. At the same time, the literature in common epilepsies abounds with reports of associations and reports of nonreplication of those association studies, primarily with channel genes. These contradictory reports can mostly be explained by confounding factors unique to genetic studies. The methodology of genetic studies and their common biases and confounding factors are also explained in this review. Amid the controversy, steady progress is being made on the epilepsies of complex inheritance, which represent the most common idiopathic epilepsy. Recent discoveries show that genes influencing the developmental assembly of neural circuits and neuronal metabolism may play a more prominent role in the common epilepsies than genes affecting membrane excitability and synaptic transmission.
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Affiliation(s)
- David A Greenberg
- Division of Statistical Genetics, Mailman School of Public Health, Columbia University Medical Center, 122 West 168th Street, 6th Floor, New York, NY 10032, USA.
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Lucarini N, Verrotti A, Napolioni V, Bosco G, Curatolo P. Genetic polymorphisms and idiopathic generalized epilepsies. Pediatr Neurol 2007; 37:157-64. [PMID: 17765802 DOI: 10.1016/j.pediatrneurol.2007.06.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 03/14/2007] [Accepted: 06/01/2007] [Indexed: 10/22/2022]
Abstract
In recent years, progress in understanding the genetic basis of idiopathic generalized epilepsies has proven challenging because of their complex inheritance patterns and genetic heterogeneity. Genetic polymorphisms offer a convenient avenue for a better understanding of the genetic basis of idiopathic generalized epilepsy by providing evidence for the involvement of a given gene in these disorders, and by clarifying its pathogenetic mechanisms. Many of these genes encode for some important central nervous system ion channels (KCNJ10, KCNJ3, KCNQ2/KCNQ3, CLCN2, GABRG2, GABRA1, SCN1B, and SCN1A), while many others encode for ubiquitary enzymes that play crucial roles in various metabolic pathways (HP, ACP1, ME2, LGI4, OPRM1, GRIK1, BRD2, EFHC1, and EFHC2). We review the main genetic polymorphisms reported in idiopathic generalized epilepsy, and discusses their possible functional significance in the pathogenesis of seizures.
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Affiliation(s)
- Nazzareno Lucarini
- Department of Molecular, Cellular, and Animal Biology, University of Camerino, Camerino, Italy.
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