1
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Mir A, Song Y, Lee H, Nadeali Z, Tabatabaiefar MA. A novel de novo frameshift variant in the CHD2 gene related to intellectual and developmental disability, seizures and speech problems. Mol Genet Genomic Med 2024; 12:e2305. [PMID: 37877434 PMCID: PMC10767600 DOI: 10.1002/mgg3.2305] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 09/23/2023] [Accepted: 10/13/2023] [Indexed: 10/26/2023] Open
Abstract
BACKGROUND The chromodomain helicase DNA-binding protein 2 (CHD2) is a member of the ATP-dependent chromatin remodelling family of proteins, which are critical for the assembly and regulation of chromatin. De novo variants and deletions in the CHD2 gene have been associated with childhood-onset developmental and epileptic encephalopathies type 94 (DEE 94). This study reports a novel deleterious de novo heterozygous frameshift insertion variant in the CHD2 gene. METHODS The causative variant was diagnosed using whole-exome sequencing. Sanger sequencing and cosegregation analysis were applied to confirm the candidate variant. Multiple in silico analysis tools were employed to interpret the variant using the American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines. RESULTS A de novo deleterious variant, NM_001271.4:c.1570dup (NP_001262.3:p.Ser524PhefsTer30), in the CHD2 gene, was identified in a 16-year-old boy with an intellectual and developmental disability, seizures and speech problems. The de novo occurrence of the variant was confirmed by segregation analysis in the family. CONCLUSION The findings of this study expand the existing knowledge of variants of the CHD2 gene and provide a detailed phenotype associated with this gene. These data could have implications for genetic diagnosis and counselling in similar conditions. Moreover, this information could be useful for therapeutic purposes, including the proper administration of medication to control epilepsy.
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Affiliation(s)
- Atefeh Mir
- Department of Genetics and Molecular Biology, School of MedicineIsfahan University of Medical SciencesIsfahanIran
| | - Yongjun Song
- Division of Medical Genetics3Billion IncSeoulSouth Korea
| | - Hane Lee
- Division of Medical Genetics3Billion IncSeoulSouth Korea
| | - Zakiye Nadeali
- Department of Genetics and Molecular Biology, School of MedicineIsfahan University of Medical SciencesIsfahanIran
| | - Mohammad Amin Tabatabaiefar
- Department of Genetics and Molecular Biology, School of MedicineIsfahan University of Medical SciencesIsfahanIran
- Pediatric Inherited Diseases Research Center, Research Institute for Primordial Prevention of Noncommunicable DiseaseIsfahan University of Medical SciencesIsfahanIran
- GenTArget Corp (GTAC), Deputy of Research and TechnologyIsfahan University of Medical SciencesIsfahanIran
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2
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Muhammad T, Pastore SF, Good K, Ausió J, Vincent JB. Chromatin gatekeeper and modifier CHD proteins in development, and in autism and other neurological disorders. Psychiatr Genet 2023; 33:213-232. [PMID: 37851134 DOI: 10.1097/ypg.0000000000000353] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2023]
Abstract
Chromatin, a protein-DNA complex, is a dynamic structure that stores genetic information within the nucleus and responds to molecular/cellular changes in its structure, providing conditional access to the genetic machinery. ATP-dependent chromatin modifiers regulate access of transcription factors and RNA polymerases to DNA by either "opening" or "closing" the structure of chromatin, and its aberrant regulation leads to a variety of neurodevelopmental disorders. The chromodomain helicase DNA-binding (CHD) proteins are ATP-dependent chromatin modifiers involved in the organization of chromatin structure, act as gatekeepers of genomic access, and deposit histone variants required for gene regulation. In this review, we first discuss the structural and functional domains of the CHD proteins, and their binding sites, and phosphorylation, acetylation, and methylation sites. The conservation of important amino acids in SWItch/sucrose non-fermenting (SWI/SNF) domains, and their protein and mRNA tissue expression profiles are discussed. Next, we convey the important binding partners of CHD proteins, their protein complexes and activities, and their involvements in epigenetic regulation. We also show the ChIP-seq binding dynamics for CHD1, CHD2, CHD4, and CHD7 proteins at promoter regions of histone genes, as well as several genes that are critical for neurodevelopment. The role of CHD proteins in development is also discussed. Finally, this review provides information about CHD protein mutations reported in autism and neurodevelopmental disorders, and their pathogenicity. Overall, this review provides information on the progress of research into CHD proteins, their structural and functional domains, epigenetics, and their role in stem cell, development, and neurological disorders.
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Affiliation(s)
- Tahir Muhammad
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Institute of Medical Science, University of Toronto, Toronto, ON
| | - Stephen F Pastore
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Institute of Medical Science, University of Toronto, Toronto, ON
| | - Katrina Good
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC
| | - Juan Ausió
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC
| | - John B Vincent
- Molecular Neuropsychiatry & Development (MiND) Lab, Campbell Family Mental Health Research Institute, Centre for Addiction and Mental Health
- Institute of Medical Science, University of Toronto, Toronto, ON
- Department of Psychiatry, University of Toronto, Toronto, ON, Canada
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3
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Novel Loss-of-Function Variants in CHD2 Cause Childhood-Onset Epileptic Encephalopathy in Chinese Patients. Genes (Basel) 2022; 13:genes13050908. [PMID: 35627293 PMCID: PMC9140428 DOI: 10.3390/genes13050908] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/16/2022] Open
Abstract
Developmental and epileptic encephalopathy-94 (DEE94) is a severe form of epilepsy characterized by a broad spectrum of neurodevelopmental disorders. It is caused by pathogenic CHD2 variants. While only a few pathogenic CHD2 variants have been reported with detailed clinical phenotypes, most of which lack molecular analysis. In this study, next-generation sequencing (NGS) was performed to identify likely pathogenic CHD2 variants in patients with epilepsy. Three likely pathogenic variants were finally identified in different patients. The seizure onset ages were from two years to six years. Patients 1 and 2 had developmental delays before epilepsy, while patient 3 had intellectual regression after the first seizure onset. The observed seizures were myoclonic, febrile, and generalized tonic-clonic, which had been controlled by different combinations of antiepileptic drugs. Two de novo (c.1809_1809+1delGGinsTT, p.? and c.3455+2_3455+3insTG, p.?) and one maternal (c.3783G>A, p.W1261*) variant were identified, which were all predicted to be pathogenic/likely pathogenic. Molecular analysis was performed in patient 1, and we detected aberrantly spliced products, proving the pathogenicity of this CHD2 variant. New cases with novel variants, along with a detailed clinical and molecular analysis, are important for a better understanding of CHD2-related epileptic encephalopathy.
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4
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Feng W, Fang F, Wang X, Chen C, Lu J, Deng J. Clinical analysis of
CHD2
gene mutations in pediatric patients with epilepsy. Pediatr Investig 2022; 6:93-99. [PMID: 35774528 PMCID: PMC9218986 DOI: 10.1002/ped4.12321] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 03/10/2022] [Indexed: 11/10/2022] Open
Affiliation(s)
- Weixing Feng
- Department of Neurology Beijing Children's Hospital, Capital Medical University, National Center for Children's Health Beijing China
| | - Fang Fang
- Department of Neurology Beijing Children's Hospital, Capital Medical University, National Center for Children's Health Beijing China
| | - Xiaohui Wang
- Department of Neurology Beijing Children's Hospital, Capital Medical University, National Center for Children's Health Beijing China
| | - Chunhong Chen
- Department of Neurology Beijing Children's Hospital, Capital Medical University, National Center for Children's Health Beijing China
| | - Junlan Lu
- Department of Neurology Beijing Children's Hospital, Capital Medical University, National Center for Children's Health Beijing China
| | - Jie Deng
- Department of Neurology Beijing Children's Hospital, Capital Medical University, National Center for Children's Health Beijing China
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5
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Luo X, Sun X, Wang Y, Lin L, Yuan F, Wang S, Zhang W, Ji X, Liu M, Wu S, Lan X, Zhang J, Yan J, Zeng F, Chen Y. Clinical Study of 8 Cases of CHD2 Gene Mutation–Related Neurological Diseases and Their Mechanisms. Front Cell Dev Biol 2022; 10:853127. [PMID: 35386198 PMCID: PMC8977407 DOI: 10.3389/fcell.2022.853127] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/01/2022] [Indexed: 01/15/2023] Open
Abstract
Background: The chromodomain helicase DNA-binding protein 2 (CHD2) gene, is an ATPase and part of the CHD family of chromatin remodelers. Mutations in the CHD2 gene are inherited in an autosomal-dominant manner and can lead to intellectual disability, epilepsy, and autism. We investigated the clinical characteristics of CHD2-related conditions and their possible pathogenesis. Methods: We collected and analysed the clinical data of patients that were identified as having CHD2 mutations. Genetic testing was performed using targeted sequencing or whole-exome sequencing. We analysed the expression of CHD2 and repressor element 1-silencing transcription factor (REST) in blood samples using quantitative PCR and the conservation of the mutations. The CHD2 mutations we identified were compared with the known mutations reported in the CHD2-related literature. Results: Eight patients with CHD2 gene mutations were analysed. Six mutations were identified; four were unreported previously (c.670C>T; c.4012A>C; c.2416dup; c.1727–1728insAT), and two were known mutations: c.5035C>T (two cases) and c.4173dup (two cases). Among these mutations, seven were de novo mutations, and one could not be determined because the parents refused genetic testing. The clinical manifestations included mild or severe intellectual disability, epilepsy, and behavioural abnormalities. Quantitative PCR showed that the CHD2 gene expression levels among the patients, parents, and the controls were not significantly different. The levels of REST gene expression in the patients were significantly higher than those of the controls; thus, mutation of the CHD2 gene led to an increase in the expression level of the REST gene. The mutations reported were all located in conserved positions in different species. Among the various medications administered for treatment, valproate showed the best results for the treatment of epilepsy caused by CHD2 gene mutation. Conclusion: Mutation in CHD2 did not lead to a significant decrease in its expression level, indicating that the clinical phenotype was unrelated to its expression level, and the mutant protein may retain some function. Most of the mutations relatively stable. In addition, the clinical manifestations from the same mutation in the CHD2 gene were different among the known cases; this may be related to the regulation of REST or other regulatory factors.
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Affiliation(s)
- Xiaona Luo
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Xiaoang Sun
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Yilin Wang
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Longlong Lin
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Fang Yuan
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Simei Wang
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Wenjing Zhang
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Xiaobing Ji
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Meiyan Liu
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Shengnan Wu
- Department of Clinical Laboratory, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Xiaoping Lan
- Department of Clinical Laboratory, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Zhang
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
| | - Jingbin Yan
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Fanyi Zeng
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
| | - Yucai Chen
- Department of Neurology, Shanghai Children’s Hospital, Shanghai JiaoTong University, Shanghai, China
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology and Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, China
- *Correspondence: Yucai Chen,
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6
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Wilson KD, Porter EG, Garcia BA. Reprogramming of the epigenome in neurodevelopmental disorders. Crit Rev Biochem Mol Biol 2022; 57:73-112. [PMID: 34601997 PMCID: PMC9462920 DOI: 10.1080/10409238.2021.1979457] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The etiology of neurodevelopmental disorders (NDDs) remains a challenge for researchers. Human brain development is tightly regulated and sensitive to cellular alterations caused by endogenous or exogenous factors. Intriguingly, the surge of clinical sequencing studies has revealed that many of these disorders are monogenic and monoallelic. Notably, chromatin regulation has emerged as highly dysregulated in NDDs, with many syndromes demonstrating phenotypic overlap, such as intellectual disabilities, with one another. Here we discuss epigenetic writers, erasers, readers, remodelers, and even histones mutated in NDD patients, predicted to affect gene regulation. Moreover, this review focuses on disorders associated with mutations in enzymes involved in histone acetylation and methylation, and it highlights syndromes involving chromatin remodeling complexes. Finally, we explore recently discovered histone germline mutations and their pathogenic outcome on neurological function. Epigenetic regulators are mutated at every level of chromatin organization. Throughout this review, we discuss mechanistic investigations, as well as various animal and iPSC models of these disorders and their usefulness in determining pathomechanism and potential therapeutics. Understanding the mechanism of these mutations will illuminate common pathways between disorders. Ultimately, classifying these disorders based on their effects on the epigenome will not only aid in prognosis in patients but will aid in understanding the role of epigenetic machinery throughout neurodevelopment.
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Affiliation(s)
- Khadija D. Wilson
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Elizabeth G. Porter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Benjamin A. Garcia
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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7
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Abstract
Chromatin is highly dynamic, undergoing continuous global changes in its structure and type of histone and DNA modifications governed by processes such as transcription, repair, replication, and recombination. Members of the chromodomain helicase DNA-binding (CHD) family of enzymes are ATP-dependent chromatin remodelers that are intimately involved in the regulation of chromatin dynamics, altering nucleosomal structure and DNA accessibility. Genetic studies in yeast, fruit flies, zebrafish, and mice underscore essential roles of CHD enzymes in regulating cellular fate and identity, as well as proper embryonic development. With the advent of next-generation sequencing, evidence is emerging that these enzymes are subjected to frequent DNA copy number alterations or mutations and show aberrant expression in malignancies and other human diseases. As such, they might prove to be valuable biomarkers or targets for therapeutic intervention.
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Affiliation(s)
- Andrej Alendar
- Division of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam 1066CX, The Netherlands
| | - Anton Berns
- Division of Molecular Genetics, The Netherlands Cancer Institute, Amsterdam 1066CX, The Netherlands
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8
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Frewer V, Gilchrist CP, Collins SE, Williams K, Seal ML, Leventer RJ, Amor DJ. A systematic review of brain MRI findings in monogenic disorders strongly associated with autism spectrum disorder. J Child Psychol Psychiatry 2021; 62:1339-1352. [PMID: 34426966 DOI: 10.1111/jcpp.13510] [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] [Accepted: 07/06/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Research on monogenic forms of autism spectrum disorder (autism) can inform our understanding of genetic contributions to the autism phenotype; yet, there is much to be learned about the pathways from gene to brain structure to behavior. This systematic review summarizes and evaluates research on brain magnetic resonance imaging (MRI) findings in monogenic conditions that have strong association with autism. This will improve understanding of the impact of genetic variability on brain structure and related behavioral traits in autism. METHODS The search strategy for this systematic review followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Risk of bias (ROB) assessment was completed on included studies using the Newcastle-Ottawa Scales. RESULTS Of 4,287 studies screened, 69 were included pertaining to 13 of the top 20 genes with the strongest association with autism. The greatest number of studies related to individuals with PTEN variants and autism. Brain MRI abnormalities were reported for 12 of the 13 genes studied, and in 51.7% of participants across all 13 genes, including 100% of participants with ARID1B variants. Specific MRI findings were highly variable, with no clear patterns emerging within or between the 13 genes, although white matter abnormalities were the most common. Few studies reported specific details about methods for acquisition and processing of brain MRI, and descriptors for brain abnormalities were variable. ROB assessment indicated high ROB for all studies, largely due to small sample sizes and lack of comparison groups. CONCLUSIONS Brain abnormalities are common in this population of individuals, in particular, children; however, a range of different brain abnormalities were reported within and between genes. Directions for future neuroimaging research in monogenic autism are suggested.
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Affiliation(s)
- Veronica Frewer
- Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, The University of Melbourne, Parkville, Vic., Australia
| | - Courtney P Gilchrist
- Murdoch Children's Research Institute, Parkville, Vic., Australia.,Neurodevelopment in Health and Disease, RMIT University, Bundoora, Vic., Australia
| | - Simonne E Collins
- Murdoch Children's Research Institute, Parkville, Vic., Australia.,School of Psychological Sciences, Turner Institute for Brain & Mental Health, Monash University, Melbourne, Vic., Australia
| | - Katrina Williams
- Monash University, Melbourne, Vic., Australia.,Monash Children's Hospital, Melbourne, Vic., Australia
| | - Marc L Seal
- Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, The University of Melbourne, Parkville, Vic., Australia
| | - Richard J Leventer
- Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, The University of Melbourne, Parkville, Vic., Australia.,Royal Children's Hospital, Parkville, Vic., Australia
| | - David J Amor
- Murdoch Children's Research Institute, Parkville, Vic., Australia.,Department of Paediatrics, The University of Melbourne, Parkville, Vic., Australia.,Royal Children's Hospital, Parkville, Vic., Australia
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9
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Benbouchta Y, De Leeuw N, Amasdl S, Sbiti A, Smeets D, Sadki K, Sefiani A. 15q26 deletion in a patient with congenital heart defect, growth restriction and intellectual disability: case report and literature review. Ital J Pediatr 2021; 47:188. [PMID: 34530895 PMCID: PMC8447573 DOI: 10.1186/s13052-021-01121-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 07/07/2021] [Indexed: 11/15/2022] Open
Abstract
Background 15q26 deletion is a relatively rare chromosomal disorder, and it is described only in few cases. Patients with this aberration show many signs and symptoms, particularly pre- and postnatal growth restriction, developmental delay, microcephaly, intellectual disability and various congenital malformations. Case presentation We report on a girl, 4 years old, of consanguineous parents, with a 15q26 deletion. Clinical manifestations included failure to thrive, developmental delay, microcephaly, dysmorphic facies with broad forehead, hypertelorism, narrowed eyelid slits and protruding columella. The patient also showed skeletal abnormalities, especially clinodactyly of the 5th finger, varus equine right foot and left club foot. Additionally, she had teething delay and divergent strabismus. Heart ultrasound displayed two atrial septal defects with left-to-right shunt, enlarging the right cavities. Routine cytogenetic analysis revealed a shortened 15q chromosome. Subsequent array analysis disclosed a terminal 9.15 Mb deletion at subband 15q26.1-q26.3. Four candidate genes associated with 15q26 deletion phenotype were within the deleted region, i.e. IGF1R, NR2F2, CHD2 and MEF2A. Conclusion We report on an additional case of 15q26 monosomy, characterized by array-CGH. Molecular cytogenetic analysis allowed us to identify the exact size of the deletion, and four candidate genes for genotype-phenotype correlation. 15q26 monosomy should be considered when growth retardation is associated with hearing anomalies and congenital heart defect, especially atrioventricular septal defects (AVSDs) and/or aortic arch anomaly (AAA).
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Affiliation(s)
- Yahya Benbouchta
- Department of Medical Genetics, National Institute of Health, Rabat, Morocco. .,Laboratory of Human Pathology, Faculty of Sciences, Mohammed V University, Rabat, Morocco.
| | - Nicole De Leeuw
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, Netherlands
| | - Saadia Amasdl
- Department of Medical Genetics, National Institute of Health, Rabat, Morocco
| | - Aziza Sbiti
- Department of Medical Genetics, National Institute of Health, Rabat, Morocco
| | - Dominique Smeets
- Research Team in Genomics and Molecular Epidemiology of Genetic Diseases, Genomic Center of Human Pathologies, Medical School and Pharmacy, University Mohammed V, Rabat, Morocco
| | - Khalid Sadki
- Laboratory of Human Pathology, Faculty of Sciences, Mohammed V University, Rabat, Morocco
| | - Abdelaziz Sefiani
- Department of Medical Genetics, National Institute of Health, Rabat, Morocco.,Research Team in Genomics and Molecular Epidemiology of Genetic Diseases, Genomic Center of Human Pathologies, Medical School and Pharmacy, University Mohammed V, Rabat, Morocco
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10
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Sadler B, Wilborn J, Antunes L, Kuensting T, Hale AT, Gannon SR, McCall K, Cruchaga C, Harms M, Voisin N, Reymond A, Cappuccio G, Brunetti-Pierri N, Tartaglia M, Niceta M, Leoni C, Zampino G, Ashley-Koch A, Urbizu A, Garrett ME, Soldano K, Macaya A, Conrad D, Strahle J, Dobbs MB, Turner TN, Shannon CN, Brockmeyer D, Limbrick DD, Gurnett CA, Haller G. Rare and de novo coding variants in chromodomain genes in Chiari I malformation. Am J Hum Genet 2021; 108:100-114. [PMID: 33352116 DOI: 10.1016/j.ajhg.2020.12.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 11/24/2020] [Indexed: 12/16/2022] Open
Abstract
Chiari I malformation (CM1), the displacement of the cerebellum through the foramen magnum into the spinal canal, is one of the most common pediatric neurological conditions. Individuals with CM1 can present with neurological symptoms, including severe headaches and sensory or motor deficits, often as a consequence of brainstem compression or syringomyelia (SM). We conducted whole-exome sequencing (WES) on 668 CM1 probands and 232 family members and performed gene-burden and de novo enrichment analyses. A significant enrichment of rare and de novo non-synonymous variants in chromodomain (CHD) genes was observed among individuals with CM1 (combined p = 2.4 × 10-10), including 3 de novo loss-of-function variants in CHD8 (LOF enrichment p = 1.9 × 10-10) and a significant burden of rare transmitted variants in CHD3 (p = 1.8 × 10-6). Overall, individuals with CM1 were found to have significantly increased head circumference (p = 2.6 × 10-9), with many harboring CHD rare variants having macrocephaly. Finally, haploinsufficiency for chd8 in zebrafish led to macrocephaly and posterior hindbrain displacement reminiscent of CM1. These results implicate chromodomain genes and excessive brain growth in CM1 pathogenesis.
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11
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Hirose S, Tanaka Y, Shibata M, Kimura Y, Ishikawa M, Higurashi N, Yamamoto T, Ichise E, Chiyonobu T, Ishii A. Application of induced pluripotent stem cells in epilepsy. Mol Cell Neurosci 2020; 108:103535. [DOI: 10.1016/j.mcn.2020.103535] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023] Open
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12
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Feng Y, Duan C, Luo Z, Xiao W, Tian F. Silencing miR-20a-5p inhibits axonal growth and neuronal branching and prevents epileptogenesis through RGMa-RhoA-mediated synaptic plasticity. J Cell Mol Med 2020; 24:10573-10588. [PMID: 32779334 PMCID: PMC7521253 DOI: 10.1111/jcmm.15677] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2020] [Revised: 06/24/2020] [Accepted: 07/03/2020] [Indexed: 12/18/2022] Open
Abstract
Epileptogenesis is a potential process. Mossy fibre sprouting (MFS) and synaptic plasticity promote epileptogenesis. Overexpression of repulsive guidance molecule a (RGMa) prevents epileptogenesis by inhibiting MFS. However, other aspects underlying the RGMa regulatory process of epileptogenesis have not been elucidated. We studied whether RGMa could be modulated by microRNAs and regulated RhoA in epileptogenesis. Using microRNA databases, we selected four miRNAs as potential candidates. We further experimentally confirmed miR‐20a‐5p as a RGMa upstream regulator. Then, in vitro, by manipulating miR‐20a‐5p and RGMa, we investigated the regulatory relationship between miR‐20a‐5p, RGMa and RhoA, and the effects of this pathway on neuronal morphology. Finally, in the epilepsy animal model, we determined whether the miR‐20a‐5p‐RGMa‐RhoA pathway influenced MFS and synaptic plasticity and then modified epileptogenesis. Our results showed that miR‐20a‐5p regulated RGMa and that RGMa regulated RhoA in vitro. Furthermore, in primary hippocampal neurons, the miR‐20a‐5p‐RGMa‐RhoA pathway regulated axonal growth and neuronal branching; in the PTZ‐induced epilepsy model, silencing miR‐20a‐5p prevented epileptogenesis through RGMa‐RhoA‐mediated synaptic plasticity but did not change MFS. Overall, we concluded that silencing miR‐20a‐5p inhibits axonal growth and neuronal branching and prevents epileptogenesis through RGMa‐RhoA‐mediated synaptic plasticity in the PTZ‐induced epilepsy model, thereby providing a possible strategy to prevent epileptogenesis.
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Affiliation(s)
- Yanyan Feng
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Chaojun Duan
- Department of Oncology, Xiangya Hospital, Central South University, Changsha, China
| | - Zhaohui Luo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Wenbiao Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Fafa Tian
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
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13
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Gawel K, Langlois M, Martins T, van der Ent W, Tiraboschi E, Jacmin M, Crawford AD, Esguerra CV. Seizing the moment: Zebrafish epilepsy models. Neurosci Biobehav Rev 2020; 116:1-20. [PMID: 32544542 DOI: 10.1016/j.neubiorev.2020.06.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/20/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022]
Abstract
Zebrafish are now widely accepted as a valuable animal model for a number of different central nervous system (CNS) diseases. They are suitable both for elucidating the origin of these disorders and the sequence of events culminating in their onset, and for use as a high-throughput in vivo drug screening platform. The availability of powerful and effective techniques for genome manipulation allows the rapid modelling of different genetic epilepsies and of conditions with seizures as a core symptom. With this review, we seek to summarize the current knowledge about existing epilepsy/seizures models in zebrafish (both pharmacological and genetic) and compare them with equivalent rodent and human studies. New findings obtained from the zebrafish models are highlighted. We believe that this comprehensive review will highlight the value of zebrafish as a model for investigating different aspects of epilepsy and will help researchers to use these models to their full extent.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | | | - Teresa Martins
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Ettore Tiraboschi
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Neurophysics Group, Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, Building 14, 38068, Rovereto, TN, Italy
| | - Maxime Jacmin
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Alexander D Crawford
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg; Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.
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14
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Chen J, Zhang J, Liu A, Zhang L, Li H, Zeng Q, Yang Z, Yang X, Wu X, Zhang Y. CHD2-related epilepsy: novel mutations and new phenotypes. Dev Med Child Neurol 2020; 62:647-653. [PMID: 31677157 DOI: 10.1111/dmcn.14367] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/21/2019] [Indexed: 12/16/2022]
Abstract
The aim of this report was to refine the genotypes and phenotypes of chromodomain helicase DNA-binding protein 2 (CHD2)-related epilepsy. Seventeen patients with CHD2 mutations were enrolled. CHD2 mutations were identified by application of next-generation sequencing of epilepsy or whole exome sequencing. Sixteen mutations were identified, among which 15 have not yet been reported. Thirteen mutations were de novo. Age at seizure onset ranged from 3 months to 10 years 5 months. Seizures observed were generalized tonic-clonic, myoclonic, atonic, atypical absence, focal, and myoclonic-atonic. Epileptic spasms occurred in two patients. Developmental disability was present in 14 patients. Autism features were observed in seven patients. Video electroencephalogram was abnormal in 15 patients. Five patients were diagnosed with non-specific epileptic encephalopathy, two with epilepsy with myoclonic-atonic seizures, two with Lennox-Gastaut syndrome, two with febrile seizures plus, and one with West syndrome. Seizures were controlled in nine patients. Q1392TfsX17 may be a hot-spot mutation of CHD2. West syndrome was observed as a new phenotype of CHD2 mutation. The severity of the phenotypes of CHD2 mutations ranged from mild febrile seizures to severe epileptic encephalopathy. WHAT THIS PAPER ADDS: Q1392TfsX17 maybe the hot-spot mutation of CHD2. West syndrome could be a new phenotype of CHD2 mutation.
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Affiliation(s)
- Jiaoyang Chen
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Jing Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Aijie Liu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Liping Zhang
- Department of Pediatrics, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Hua Li
- Department of Pediatrics, Guangdong 999 Brain Hospital, Guangzhou, China
| | - Qi Zeng
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Zhixian Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiaoling Yang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Xiru Wu
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Yuehua Zhang
- Department of Pediatrics, Peking University First Hospital, Beijing, China
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15
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Shahin Varnoosfaderani F, Palau A, Dong W, Persson J, Durand-Dubief M, Svensson JP, Lennartsson A. A regulatory role for CHD2 in myelopoiesis. Epigenetics 2020; 15:702-714. [PMID: 31900031 PMCID: PMC7574388 DOI: 10.1080/15592294.2019.1710913] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The transcriptional program that dictates haematopoietic cell fate and differentiation requires an epigenetic regulatory and memory function, provided by a network of epigenetic factors that regulate DNA methylation, post-translational histone modifications and chromatin structure. Disturbed epigenetic regulation causes perturbations in the blood cell differentiation program that results in various types of haematopoietic disorders. Thus, accurate epigenetic regulation is essential for functional haematopoiesis. In this study, we used a CRISPR-Cas9 screening approach to identify new epigenetic regulators in myeloid differentiation. We designed a Chromatin-UMI CRISPR guide library targeting 1092 epigenetic regulators. Phorbol 12-myristate 13-acetate (PMA) treatment of the chronic myeloid leukaemia cell line K-562 was used as a megakaryocytic myeloid differentiation model. Both previously described developmental epigenetic regulators and novel factors were identified in our screen. In this study, we validated and characterized a role for the chromatin remodeller CHD2 in myeloid proliferation and megakaryocytic differentiation.
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Affiliation(s)
| | - Anna Palau
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet , Stockholm, Sweden
| | - Wenbo Dong
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet , Stockholm, Sweden
| | - Jenna Persson
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Stockholm, Sweden.,High Throughput Genome Engineering, Science for Life Laboratory , Stockholm, Sweden
| | - Mickaël Durand-Dubief
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet , Stockholm, Sweden
| | - J Peter Svensson
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet , Stockholm, Sweden
| | - Andreas Lennartsson
- Department of Biosciences and Nutrition, Neo, Karolinska Institutet , Stockholm, Sweden
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16
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Genetic mechanisms of regression in autism spectrum disorder. Neurosci Biobehav Rev 2019; 102:208-220. [DOI: 10.1016/j.neubiorev.2019.04.022] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 02/12/2019] [Accepted: 04/28/2019] [Indexed: 12/17/2022]
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17
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Song M, Tian F, Xia H, Xie Y. Repulsive guidance molecule a suppresses seizures and mossy fiber sprouting via the FAK‑p120RasGAP‑Ras signaling pathway. Mol Med Rep 2019; 19:3255-3262. [PMID: 30816469 DOI: 10.3892/mmr.2019.9951] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 01/21/2019] [Indexed: 11/05/2022] Open
Abstract
Repulsive guidance molecule a (RGMa) is a membrane‑associated glycoprotein that regulates axonal guidance and inhibits axon outgrowth. In our previous study, we hypothesized that RGMa may be involved in temporal lobe epilepsy (TLE) via the repulsive guidance molecule a (RGMa)‑focal adhesion kinase (FAK)‑Ras signaling pathway. To investigate the role of RGMa in epilepsy, recombinant RGMa protein and FAK inhibitor 14 was intracerebroventricularly injected into a pentylenetetrazol (PTZ) kindling model and Timm staining, co‑immunoprecipitation and western blotting analyses were subsequently performed. The results of the present study revealed that intracerebroventricular injection of recombinant RGMa protein reduced the phosphorylation of FAK (Tyr397) and intracerebroventricular injection of FAK inhibitor 14 reduced the interaction between FAK and p120GAP, as wells as Ras expression. Recombinant RGMa protein and FAK inhibitor 14 exerted seizure‑suppressant effects; however, recombinant RGMa protein but not FAK inhibitor 14 suppressed mossy fiber sprouting in the PTZ kindling model. Collectively, these results demonstrated that RGMa may be considered as a potential therapeutic agent for epilepsy, and that RGMa may exert the aforementioned biological effects partly via the FAK‑p120GAP‑Ras signaling pathway.
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Affiliation(s)
- Mingyu Song
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Fafa Tian
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Huang Xia
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yuanyuan Xie
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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18
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Lamar KMJ, Carvill GL. Chromatin Remodeling Proteins in Epilepsy: Lessons From CHD2-Associated Epilepsy. Front Mol Neurosci 2018; 11:208. [PMID: 29962935 PMCID: PMC6013553 DOI: 10.3389/fnmol.2018.00208] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 05/25/2018] [Indexed: 12/24/2022] Open
Abstract
The chromodomain helicase DNA-binding (CHD) family of proteins are ATP-dependent chromatin remodelers that contribute to the reorganization of chromatin structure and deposition of histone variants necessary to regulate gene expression. CHD proteins play an important role in neurodevelopment, as pathogenic variants in CHD1, CHD2, CHD4, CHD7 and CHD8 have been associated with a range of neurological phenotypes, including autism spectrum disorder (ASD), intellectual disability (ID) and epilepsy. Pathogenic variants in CHD2 are associated with developmental epileptic encephalopathy (DEE) in humans, however little is known about how these variants contribute to this disorder. Of the nine CHD family members, CHD2 is the only one that leads to a brain-restricted phenotype when disrupted in humans. This suggests that despite being expressed ubiquitously, CHD2 has a unique role in human brain development and function. In this review, we will discuss the phenotypic spectrum of patients with pathogenic variants in CHD2, current animal models of CHD2 deficiency, and the role of CHD2 in proliferation, neurogenesis, neuronal differentiation, chromatin remodeling and DNA-repair. We also consider how CHD2 depletion can affect each of these biological mechanisms and how these defects may underpin neurodevelopmental disorders including epilepsy.
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Affiliation(s)
- Kay-Marie J Lamar
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Gemma L Carvill
- Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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19
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Sun H, Wang Z, Zhang Z, Xiao Q, Mawed S, Xu Z, Zhang X, Yang H, Zhu M, Xue M, Liu X, Zhang W, Zhen Y, Wang Q, Pan Y. Genomic signatures reveal selection of characteristics within and between Meishan pig populations. Anim Genet 2018; 49:119-126. [PMID: 29508928 DOI: 10.1111/age.12642] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/18/2017] [Indexed: 12/21/2022]
Abstract
The Chinese Meishan pig breed is well known for its high prolificacy. Moreover, this breed can be divided into three types based on their body size: big Meishan, middle Meishan (MMS) and small Meishan (SMS) pigs. Few studies have reported on the genetic signatures of Meishan pigs, particularly on a genome-wide scale. Exploring for genetic signatures could be quite valuable for revealing the genetic architecture of phenotypic variation. Thus, we performed research in two parts based on the genome reducing and sequencing data of 143 Meishan pigs (74 MMS pigs, 69 SMS pigs). First, we detected the selection signatures among all Meishan pigs studied using the relative extended haplotype homozygosity test. Second, we detected the selection signatures between MMS and SMS pigs using the cross-population extended haplotype homozygosity and FST methods. A total of 111 398 SNPs were identified from the sequenced genomes. In the population analysis, the most significant genes were associated with the mental development (RGMA), reproduction (HDAC4, FOXL2) and lipid metabolism (ACACB). From the cross-population analysis, we detected genes related to body weight (SPDEF, PACSIN1) in both methods. We suggest that rs341373351, located within the PACSIN1 gene, might be the causal variant. This study may have achieved consistency between selection signatures and characteristics within and between Meishan pig populations. These findings can provide insight into investigating the molecular background of high prolificacy and body size in pig.
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Affiliation(s)
- H Sun
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Z Wang
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Z Zhang
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Q Xiao
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - S Mawed
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Z Xu
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - X Zhang
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, 200240, China
| | - H Yang
- National Station of Animal Husbandry, Beijing, 100125, China
| | - M Zhu
- Jiangshu Station of Animal Husbandry, Nanjing, 210036, China
| | - M Xue
- National Station of Animal Husbandry, Beijing, 100125, China
| | - X Liu
- Jiangshu Station of Animal Husbandry, Nanjing, 210036, China
| | - W Zhang
- Jiangshu Station of Animal Husbandry, Nanjing, 210036, China
| | - Y Zhen
- National Station of Animal Husbandry, Beijing, 100125, China
| | - Q Wang
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, 200240, China
| | - Y Pan
- Department of Animal Science, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, 200240, China.,Shanghai Key Laboratory of Veterinary Biotechnology, Shanghai, 200240, China
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20
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Moccia A, Martin DM. Nervous system development and disease: A focus on trithorax related proteins and chromatin remodelers. Mol Cell Neurosci 2018; 87:46-54. [PMID: 29196188 PMCID: PMC5828982 DOI: 10.1016/j.mcn.2017.11.016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 11/08/2017] [Accepted: 11/27/2017] [Indexed: 01/12/2023] Open
Abstract
The nervous system comprises many different cell types including neurons, glia, macrophages, and immune cells, each of which is defined by specific patterns of gene expression, morphology, function, and anatomical location. Establishment of these complex and highly regulated cell fates requires spatial and temporal coordination of gene transcription. Open chromatin (euchromatin) allows transcription factors to interact with gene promoters and activate lineage specific genes, whereas closed chromatin (heterochromatin) remains inaccessible to transcriptional activation. Changes in the genome-wide distribution of euchromatin accompany transcriptional plasticity that allows the diversity of mature cell fates to be generated during development. In the past 20years, many new genes and gene families have been identified to participate in regulation of chromatin accessibility. These genes include chromatin remodelers that interact with Trithorax group (TrxG) and Polycomb group (PcG) proteins to activate or repress transcription, respectively. Here we review the role of TrxG proteins in neurodevelopment and disease.
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Affiliation(s)
- Amanda Moccia
- Department of Human Genetics, The University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Donna M Martin
- Department of Human Genetics, The University of Michigan Medical School, Ann Arbor, MI 48109, United States; Department of Pediatrics and Communicable Diseases, The University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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21
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Ortega-Moreno L, Giráldez BG, Soto-Insuga V, Losada-Del Pozo R, Rodrigo-Moreno M, Alarcón-Morcillo C, Sánchez-Martín G, Díaz-Gómez E, Guerrero-López R, Serratosa JM. Molecular diagnosis of patients with epilepsy and developmental delay using a customized panel of epilepsy genes. PLoS One 2017; 12:e0188978. [PMID: 29190809 PMCID: PMC5708701 DOI: 10.1371/journal.pone.0188978] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 11/16/2017] [Indexed: 12/30/2022] Open
Abstract
Pediatric epilepsies are a group of disorders with a broad phenotypic spectrum that are associated with great genetic heterogeneity, thus making sequential single-gene testing an impractical basis for diagnostic strategy. The advent of next-generation sequencing has increased the success rate of epilepsy diagnosis, and targeted resequencing using genetic panels is the a most cost-effective choice. We report the results found in a group of 87 patients with epilepsy and developmental delay using targeted next generation sequencing (custom-designed Haloplex panel). Using this gene panel, we were able to identify disease-causing variants in 17 out of 87 (19.5%) analyzed patients, all found in known epilepsy-associated genes (KCNQ2, CDKL5, STXBP1, SCN1A, PCDH19, POLG, SLC2A1, ARX, ALG13, CHD2, SYNGAP1, and GRIN1). Twelve of 18 variants arose de novo and 6 were novel. The highest yield was found in patients with onset in the first years of life, especially in patients classified as having early-onset epileptic encephalopathy. Knowledge of the underlying genetic cause provides essential information on prognosis and could be used to avoid unnecessary studies, which may result in a greater diagnostic cost-effectiveness.
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Affiliation(s)
- Laura Ortega-Moreno
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Beatriz G. Giráldez
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Victor Soto-Insuga
- Department of Pediatrics, Hospital Universitario Fundación Jiménez Díaz, UAM, Madrid, Spain
| | - Rebeca Losada-Del Pozo
- Department of Pediatrics, Hospital Universitario Fundación Jiménez Díaz, UAM, Madrid, Spain
| | - María Rodrigo-Moreno
- Department of Pediatrics, Hospital Universitario Fundación Jiménez Díaz, UAM, Madrid, Spain
| | - Cristina Alarcón-Morcillo
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Gema Sánchez-Martín
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Esther Díaz-Gómez
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - Rosa Guerrero-López
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
| | - José M. Serratosa
- Neurology Lab and Epilepsy Unit, Department of Neurology, IIS- Fundación Jiménez Díaz, UAM, Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Madrid, Spain
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22
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Repulsive Guidance Molecule a (RGMa) Induces Neuropathological and Behavioral Changes That Closely Resemble Parkinson's Disease. J Neurosci 2017; 37:9361-9379. [PMID: 28842419 DOI: 10.1523/jneurosci.0084-17.2017] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2017] [Revised: 07/12/2017] [Accepted: 08/11/2017] [Indexed: 01/06/2023] Open
Abstract
Repulsive guidance molecule member a (RGMa) is a membrane-associated or released guidance molecule that is involved in axon guidance, cell patterning, and cell survival. In our previous work, we showed that RGMa is significantly upregulated in the substantia nigra of patients with Parkinson's disease. Here we demonstrate the expression of RGMa in midbrain human dopaminergic (DA) neurons. To investigate whether RGMa might model aspects of the neuropathology of Parkinson's disease in mouse, we targeted RGMa to adult midbrain dopaminergic neurons using adeno-associated viral vectors. Overexpression of RGMa resulted in a progressive movement disorder, including motor coordination and imbalance, which is typical for a loss of DA release in the striatum. In line with this, RGMa induced selective degeneration of dopaminergic neurons in the substantia nigra (SN) and affected the integrity of the nigrostriatal system. The degeneration of dopaminergic neurons was accompanied by a strong microglia and astrocyte activation. The behavioral, molecular, and anatomical changes induced by RGMa in mice are remarkably similar to the clinical and neuropathological hallmarks of Parkinson's disease. Our data indicate that dysregulation of RGMa plays an important role in the pathology of Parkinson's disease, and antibody-mediated functional interference with RGMa may be a disease modifying treatment option.SIGNIFICANCE STATEMENT Parkinson's disease (PD) is a neurodegenerative disease characterized by severe motor dysfunction due to progressive degeneration of mesencephalic dopaminergic (DA) neurons in the substantia nigra. To date, there is no regenerative treatment available. We previously showed that repulsive guidance molecule member a (RGMa) is upregulated in the substantia nigra of PD patients. Adeno-associated virus-mediated targeting of RGMa to mouse DA neurons showed that overexpression of this repulsive axon guidance and cell patterning cue models the behavioral and neuropathological characteristics of PD in a remarkable way. These findings have implications for therapy development as interfering with the function of this specific axon guidance cue may be beneficial to the survival of DA neurons.
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23
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Teixeira WG, Marques FK, Freire MCM. Retrospective karyotype study in mentally retarded patients. Rev Assoc Med Bras (1992) 2016; 62:262-8. [PMID: 27310551 DOI: 10.1590/1806-9282.62.03.262] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 11/04/2014] [Indexed: 11/21/2022] Open
Abstract
OBJECTIVE To describe the chromosomal alterations in patients with mental retardation (MR) using G-banding karyotype analysis. METHOD A retrospective study of the results G-banding karyotype analysis of 369 patients investigated for MR was performed. Based on the structural rearrangements found, the authors searched all chromosomal regions related with breakpoints, and these were compared with the literature on MR and databases. RESULTS 338 (91.6%) normal cases, and 31 (8.4%) with some type of chromosomal abnormality were identified. Among the altered cases, 21 patients (67.8%) were identified with structural chromosomal alterations, nine (29%) with numerical alterations, and one (3.2%) with numerical and structural alterations. CONCLUSION Structural chromosomal abnormalities were observed more frequently in this study. G-banding karyotyping contributes to the investigation of the causes of MR, showing that this technique can be useful for initial screening of patients. However, higher resolution techniques such as array based comparative genomic hybridization (aCGH) and multiplex ligation-dependent probe amplification (MPLA) can detect submicroscopic alterations commonly associated with MR.
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Affiliation(s)
- Wellcy Gonçalves Teixeira
- Instituto Hermes Pardini, Laboratory Specialist, Belo Horizonte MG , Brazil, MSc in General and Applied Biology - Laboratory Specialist at Instituto Hermes Pardini, Belo Horizonte, MG, Brazil
| | - Fabiana Kalina Marques
- Instituto Hermes Pardini, Belo Horizonte MG , Brazil, MSc in Genetics - Researcher at Instituto Hermes Pardini, Belo Horizonte, MG, Brazil
| | - Maíra Cristina Menezes Freire
- Instituto Hermes Pardini, Belo Horizonte MG , Brazil, PhD in Genetics - Researcher at Instituto Hermes Pardini, Belo Horizonte, MG, Brazil
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24
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Shen T, Ji F, Yuan Z, Jiao J. CHD2 is Required for Embryonic Neurogenesis in the Developing Cerebral Cortex. Stem Cells 2016; 33:1794-806. [PMID: 25786798 DOI: 10.1002/stem.2001] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 02/02/2015] [Accepted: 02/06/2015] [Indexed: 11/08/2022]
Abstract
Chromodomain helicase DNA-binding protein 2 (CHD2) has been associated with a broad spectrum of neurodevelopmental disorders, such as autism spectrum disorders and intellectual disability. However, it is largely unknown whether and how CHD2 is involved in brain development. Here, we demonstrate that CHD2 is predominantly expressed in Pax6(+) radial glial cells (RGs) but rarely expressed in Tbr2(+) intermediate progenitors (IPs). Importantly, the suppression of CHD2 expression inhibits the self-renewal of RGs and increases the generation of IPs and the production of neurons. CHD2 mediates these functions by directly binding to the genomic region of repressor element 1-silencing transcription factor (REST), thereby regulating the expression of REST. Furthermore, the overexpression of REST rescues the defect in neurogenesis caused by CHD2 knockdown. Taken together, these findings demonstrate an essential role of CHD2 in the maintenance of the RGs self-renewal levels, the subsequent generation of IPs, and neuronal output during neurogenesis in cerebral cortical development, suggesting that inactivation of CHD2 during neurogenesis might contribute to abnormal neurodevelopment.
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Affiliation(s)
- Tianjin Shen
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China.,University of Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Fen Ji
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Zengqiang Yuan
- State Key Laboratory of Brain and Cognitive Sciences, Institute of Biophysics, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Jianwei Jiao
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, People's Republic of China
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25
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Lentiviral Vector-Induced Overexpression of RGMa in the Hippocampus Suppresses Seizures and Mossy Fiber Sprouting. Mol Neurobiol 2016; 54:1379-1391. [PMID: 26843113 DOI: 10.1007/s12035-016-9744-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 01/22/2016] [Indexed: 10/22/2022]
Abstract
Repulsive guidance molecule a (RGMa) is a membrane-bound protein that inhibits axon outgrowth in the central nervous system. Temporal lobe epilepsy (TLE) is a common neurological disorder characterized by recurrent spontaneous seizures. To explore the role of RGMa in epilepsy, we investigated the expression of RGMa in patients with TLE, pilocarpine-induced rat model, and pentylenetetrazol kindling model of epilepsy, and then we performed behavioral, histological, and electrophysiological analysis by lentivirus-mediated overexpression of RGMa in the hippocampus of animal model. We found that RGMa was significantly decreased in TLE patients and in experimental rats from 6 h to 60 days after pilocarpine-induced seizures. In two types of epileptic animal models, pilocarpine-induced model and pentylenetetrazol kindling model, overexpression of RGMa in the hippocampus of rats exerted seizure-suppressant effects. The reduced spontaneous seizures were accompanied by attenuation of hippocampal mossy fiber sprouting. In addition, overexpression of RGMa inhibited hyperexcitability of hippocampal neurons via suppressing NMDAR-mediated currents in Mg2+-free-induced organotypic slice model. Collectively, these results demonstrate that overexpression of RGMa could be an alternative strategy for epilepsy therapy.
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Verhoeven WM, Egger JI, Knegt AC, Zuydam J, Kleefstra T. Absence epilepsy and the CHD2 gene: an adolescent male with moderate intellectual disability, short-lasting psychoses, and an interstitial deletion in 15q26.1-q26.2. Neuropsychiatr Dis Treat 2016; 12:1135-9. [PMID: 27274247 PMCID: PMC4869798 DOI: 10.2147/ndt.s102272] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Deletions of the 15q26 region encompassing the chromodomain helicase DNA binding domain 2 (CHD2) gene have been associated with intellectual disability, behavioral problems, and several types of epilepsy. Including the cases mentioned in ECARUCA (European cytogeneticists association register of unbalanced chromosome aberrations) and DECIPHER (database of genomic variation and phenotype in humans using ensembl resources), so far, a total of 13 intellectually disabled patients with a genetically proven deletion of the CHD2 gene are described, of whom eleven had a history of severe forms of epilepsy starting from a young age. In this article, a moderately intellectually disabled 15-year-old male with a 15q26.1-q26.2 interstitial deletion is reported, who was referred for analysis of two recent short-lasting psychotic episodes that were nonresponsive to antipsychotic treatment and recurrent disinhibited behaviors since early infancy. Careful interdisciplinary assessment revealed that the psychotic phenomena originated from a previously unrecognized absence epilepsy. Treatment with valproic acid was started which resulted in full remission of psychotic symptoms, and consequently, substantial improvement of behavior. It was concluded that in case of (rare) developmental disorders with genetically proven etiology, a detailed inventory of anamnestic data and description of symptomatology over time may elucidate epilepsy-related psychopathology for which a specific treatment regimen is needed.
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Affiliation(s)
- Willem Ma Verhoeven
- Centre of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, Venray, the Netherlands; Department of Psychiatry, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Jos Im Egger
- Centre of Excellence for Neuropsychiatry, Vincent van Gogh Institute for Psychiatry, Venray, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, the Netherlands; Behavioural Science Institute, Radboud University, Nijmegen, the Netherlands
| | - Alida C Knegt
- Department of Clinical Genetics, University of Amsterdam Medical Center, Amsterdam, the Netherlands
| | - José Zuydam
- Reigersdaal Institute for Intellectual Disabilities, Heerhugowaard, the Netherlands
| | - Tjitske Kleefstra
- Department of Genetics, Radboud University Medical Centre, Nijmegen, the Netherlands
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27
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Trivisano M, Striano P, Sartorelli J, Giordano L, Traverso M, Accorsi P, Cappelletti S, Claps DJ, Vigevano F, Zara F, Specchio N. CHD2 mutations are a rare cause of generalized epilepsy with myoclonic-atonic seizures. Epilepsy Behav 2015; 51:53-6. [PMID: 26262932 DOI: 10.1016/j.yebeh.2015.06.029] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/14/2015] [Accepted: 06/15/2015] [Indexed: 11/30/2022]
Abstract
Chromodomain helicase DNA-binding protein 2 (CHD2) gene mutations have been reported in patients with myoclonic-atonic epilepsy (MAE), as well as in patients with Lennox-Gastaut, Dravet, and Jeavons syndromes and other epileptic encephalopathies featuring generalized epilepsy and intellectual disability. The aim of this study was to assess the impact of CHD2 mutations in a series of patients with MAE. Twenty patients affected by MAE were included in the study. We analyzed antecedents, age at onset, seizure semiology and frequency, EEG, treatment, and neuropsychological outcome. We sequenced the CHD2 gene with Sanger technology. We identified a CHD2 frameshift mutation in one patient (c.4256del19). He was a 17-year-old boy with no familial history for epilepsy and normal development before epilepsy onset. Epilepsy onset was at 3years and 5months: he presented with myoclonic-atonic seizures, head drops, myoclonic jerks, and absences. Interictal EEGs revealed slow background activity associated with generalized epileptiform abnormalities and photoparoxysmal response. His seizures were highly responsive to valproic acid, and an attempt to withdraw it led to seizure recurrence. Neuropsychological evaluation revealed moderate intellectual disability. Chromodomain-helicase-DNA-binding protein 2 is not the major gene associated with MAE. Conversely, CHD2 could be responsible for a proper phenotype characterized by infantile-onset generalized epilepsy, intellectual disability, and photosensitivity, which might overlap with MAE, Lennox-Gastaut, Dravet, and Jeavons syndromes.
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Affiliation(s)
- Marina Trivisano
- Neurology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Pasquale Striano
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
| | - Jacopo Sartorelli
- Pediatric Neurology and Muscular Diseases Unit, Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, "G. Gaslini" Institute, Genova, Italy
| | - Lucio Giordano
- Department of Child and Adolescent Neuropsychiatry, Spedali Civili, Brescia, Italy
| | - Monica Traverso
- Laboratory of Neurogenetics, Department of Neurosciences, "G. Gaslini" Institute, Genova, Italy
| | - Patrizia Accorsi
- Department of Child and Adolescent Neuropsychiatry, Spedali Civili, Brescia, Italy
| | | | | | - Federico Vigevano
- Neurology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Federico Zara
- Laboratory of Neurogenetics, Department of Neurosciences, "G. Gaslini" Institute, Genova, Italy
| | - Nicola Specchio
- Neurology Unit, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy.
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28
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Li W, Mills AA. Architects of the genome: CHD dysfunction in cancer, developmental disorders and neurological syndromes. Epigenomics 2015; 6:381-95. [PMID: 25333848 DOI: 10.2217/epi.14.31] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Chromatin is vital to normal cells, and its deregulation contributes to a spectrum of human ailments. An emerging concept is that aberrant chromatin regulation culminates in gene expression programs that set the stage for the seemingly diverse pathologies of cancer, developmental disorders and neurological syndromes. However, the mechanisms responsible for such common etiology have been elusive. Recent evidence has implicated lesions affecting chromatin-remodeling proteins in cancer, developmental disorders and neurological syndromes, suggesting a common source for these different pathologies. Here, we focus on the chromodomain helicase DNA binding chromatin-remodeling family and the recent evidence for its deregulation in diverse pathological conditions, providing a new perspective on the underlying mechanisms and their implications for these prevalent human diseases.
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Affiliation(s)
- Wangzhi Li
- Cold Spring Harbor Laboratory Cold Spring Harbor, NY 11724, USA
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29
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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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30
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Galizia EC, Myers CT, Leu C, de Kovel CGF, Afrikanova T, Cordero-Maldonado ML, Martins TG, Jacmin M, Drury S, Krishna Chinthapalli V, Muhle H, Pendziwiat M, Sander T, Ruppert AK, Møller RS, Thiele H, Krause R, Schubert J, Lehesjoki AE, Nürnberg P, Lerche H, Palotie A, Coppola A, Striano S, Gaudio LD, Boustred C, Schneider AL, Lench N, Jocic-Jakubi B, Covanis A, Capovilla G, Veggiotti P, Piccioli M, Parisi P, Cantonetti L, Sadleir LG, Mullen SA, Berkovic SF, Stephani U, Helbig I, Crawford AD, Esguerra CV, Kasteleijn-Nolst Trenité DGA, Koeleman BPC, Mefford HC, Scheffer IE, Sisodiya SM. CHD2 variants are a risk factor for photosensitivity in epilepsy. Brain 2015; 138:1198-207. [PMID: 25783594 PMCID: PMC4407192 DOI: 10.1093/brain/awv052] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/07/2015] [Indexed: 12/24/2022] Open
Abstract
Photosensitivity in epilepsy is common and has high heritability, but its genetic basis remains uncertain. Galizia et al. reveal an overrepresentation of unique variants of CHD2 — which encodes the transcriptional regulator ‘chromodomain helicase DNA-binding protein 2’ — in photosensitive epilepsies, and show that chd2 knockdown in zebrafish causes photosensitivity. Photosensitivity is a heritable abnormal cortical response to flickering light, manifesting as particular electroencephalographic changes, with or without seizures. Photosensitivity is prominent in a very rare epileptic encephalopathy due to de novo CHD2 mutations, but is also seen in epileptic encephalopathies due to other gene mutations. We determined whether CHD2 variation underlies photosensitivity in common epilepsies, specific photosensitive epilepsies and individuals with photosensitivity without seizures. We studied 580 individuals with epilepsy and either photosensitive seizures or abnormal photoparoxysmal response on electroencephalography, or both, and 55 individuals with photoparoxysmal response but no seizures. We compared CHD2 sequence data to publicly available data from 34 427 individuals, not enriched for epilepsy. We investigated the role of unique variants seen only once in the entire data set. We sought CHD2 variants in 238 exomes from familial genetic generalized epilepsies, and in other public exome data sets. We identified 11 unique variants in the 580 individuals with photosensitive epilepsies and 128 unique variants in the 34 427 controls: unique CHD2 variation is over-represented in cases overall (P = 2·17 × 10−5). Among epilepsy syndromes, there was over-representation of unique CHD2 variants (3/36 cases) in the archetypal photosensitive epilepsy syndrome, eyelid myoclonia with absences (P = 3·50 × 10−4). CHD2 variation was not over-represented in photoparoxysmal response without seizures. Zebrafish larvae with chd2 knockdown were tested for photosensitivity. Chd2 knockdown markedly enhanced mild innate zebrafish larval photosensitivity. CHD2 mutation is the first identified cause of the archetypal generalized photosensitive epilepsy syndrome, eyelid myoclonia with absences. Unique CHD2 variants are also associated with photosensitivity in common epilepsies. CHD2 does not encode an ion channel, opening new avenues for research into human cortical excitability.
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Affiliation(s)
- Elizabeth C Galizia
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | | | - Costin Leu
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | - Carolien G F de Kovel
- 4 Department of Medical Genetics Research, University Medical Centre Utrecht, The Netherlands
| | - Tatiana Afrikanova
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | | | - Teresa G Martins
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Maxime Jacmin
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Suzanne Drury
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - V Krishna Chinthapalli
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
| | - Hiltrud Muhle
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Manuela Pendziwiat
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Thomas Sander
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | | | - Rikke S Møller
- 9 Danish Epilepsy Centre, Dianalund, Denmark 10 Institute for Regional Health Services, University of Southern Denmark, Odense, Denmark
| | - Holger Thiele
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | - Roland Krause
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Julian Schubert
- 11 Deptartment of Neurology and Epileptology, Hertie Institut for Clinical Brain Research, Tübingen, Germany
| | - Anna-Elina Lehesjoki
- 12 Folkhälsan Institute of Genetics and Neuroscience Centre, University of Helsinki, Helsinki, Finland 13 Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
| | - Peter Nürnberg
- 8 Cologne Centre for Genomics, University of Cologne, Cologne, Germany
| | - Holger Lerche
- 11 Deptartment of Neurology and Epileptology, Hertie Institut for Clinical Brain Research, Tübingen, Germany
| | | | - Aarno Palotie
- 14 Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, UK 15 Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland 16 Program in Medical and Population Genetics and Genetic Analysis Platform, The Broad Institute of MIT and Harvard, Cambridge, USA
| | - Antonietta Coppola
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Salvatore Striano
- 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Luigi Del Gaudio
- 17 Epilepsy Centre, Neurology Department, Federico II University of Naples, Naples, Italy
| | - Christopher Boustred
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Amy L Schneider
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
| | - Nicholas Lench
- 6 North East Thames Regional Genetics Laboratories, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Bosanka Jocic-Jakubi
- 19 Department of Child Neurology, Paediatric Clinic, Clinical Centre Nis, Serbia 20 Department of Paediatric Neurology, Paediatric Clinic, Al Sabah Hospital, Kuwait
| | - Athanasios Covanis
- 21 Neurology Department, The Children's Hospital Agia Sophia, Athens, Greece
| | | | - Pierangelo Veggiotti
- 23 Department of Child Neurology and Psychiatry C. Mondino National Neurological Institute, Via Mondino, 2, 27100, Pavia, Italy 24 Brain and Behaviour Department, University of Pavia, Pavia, Italy
| | - Marta Piccioli
- 25 Neurophysiopathology Unit, San Filippo Neri Hospital, Rome, Italy
| | - Pasquale Parisi
- 26 Child Neurology, NESMOS Department, Faculty of Medicine and Psychology, Sapienza University, Rome, Italy
| | - Laura Cantonetti
- 27 Neurorehabilitation Unit, Department of Neuroscience and Neurorehabilitation, IRCCS, Bambino Gesu' Children's Hospital, Rome, Italy
| | - Lynette G Sadleir
- 28 Department of Paediatrics and Child Health, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
| | - Saul A Mullen
- 29 Florey Institute of Neurosciences and Mental Health, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia
| | - Samuel F Berkovic
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia
| | - Ulrich Stephani
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Ingo Helbig
- 7 Department of Neuropaediatrics, University Medical Centre Schleswig-Holstein and Christian-Albrechts-University of Kiel, Kiel, Germany
| | - Alexander D Crawford
- 5 Luxembourg Centre for Systems Biomedicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Camila V Esguerra
- 30 Chemical Neuroscience Group, Biotechnology Centre of Oslo, University of Oslo, Oslo, Norway 31 Laboratory for Molecular Biodiscovery, University of Leuven, Leuven, Belgium
| | | | - Bobby P C Koeleman
- 4 Department of Medical Genetics Research, University Medical Centre Utrecht, The Netherlands
| | | | - Ingrid E Scheffer
- 18 Department of Medicine, University of Melbourne, Austin Health, Melbourne, Australia 29 Florey Institute of Neurosciences and Mental Health, and Department of Paediatrics, University of Melbourne, Royal Children's Hospital, Melbourne, Australia
| | - Sanjay M Sisodiya
- 1 NIHR Biomedical Research Centre Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UK 2 Epilepsy Society, Bucks, UK
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31
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Thomas RH, Zhang LM, Carvill GL, Archer JS, Heavin SB, Mandelstam SA, Craiu D, Berkovic SF, Gill DS, Mefford HC, Scheffer IE. CHD2 myoclonic encephalopathy is frequently associated with self-induced seizures. Neurology 2015; 84:951-8. [PMID: 25672921 DOI: 10.1212/wnl.0000000000001305] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
OBJECTIVE To delineate the phenotype of early childhood epileptic encephalopathy due to de novo mutations of CHD2, which encodes the chromodomain helicase DNA binding protein 2. METHODS We analyzed the medical history, MRI, and video-EEG recordings of 9 individuals with de novo CHD2 mutations and one with a de novo 15q26 deletion encompassing CHD2. RESULTS Seizures began at a mean of 26 months (12-42) with myoclonic seizures in all 10 cases. Seven exhibited exquisite clinical photosensitivity; 6 self-induced with the television. Absence seizures occurred in 9 patients including typical (4), atypical (2), and absence seizures with eyelid myoclonias (4). Generalized tonic-clonic seizures occurred in 9 of 10 cases with a mean onset of 5.8 years. Convulsive and nonconvulsive status epilepticus were later features (6/10, mean onset 9 years). Tonic (40%) and atonic (30%) seizures also occurred. In 3 cases, an unusual seizure type, the atonic-myoclonic-absence was captured on video. A phenotypic spectrum was identified with 7 cases having moderate to severe intellectual disability and refractory seizures including tonic attacks. Their mean age at onset was 23 months. Three cases had a later age at onset (34 months) with relative preservation of intellect and an initial response to antiepileptic medication. CONCLUSION The phenotypic spectrum of CHD2 encephalopathy has distinctive features of myoclonic epilepsy, marked clinical photosensitivity, atonic-myoclonic-absence, and intellectual disability ranging from mild to severe. Recognition of this genetic entity will permit earlier diagnosis and enable the development of targeted therapies.
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Affiliation(s)
- Rhys H Thomas
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Lin Mei Zhang
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Gemma L Carvill
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - John S Archer
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Sinéad B Heavin
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Simone A Mandelstam
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Dana Craiu
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Samuel F Berkovic
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Deepak S Gill
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Heather C Mefford
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia
| | - Ingrid E Scheffer
- From the Epilepsy Research Centre (R.H.T., L.M.Z., J.S.A., S.B.H., S.A.M., S.F.B., I.E.S.), University of Melbourne, Austin Health, Heidelberg, Australia; MRC Centre for Neuropsychiatric Genetics & Genomics (R.H.T.), Hadyn Ellis Building, Cathays, Cardiff University, UK; Department of Neurology (L.M.Z.), Children's Hospital of Fudan University, Shanghai, China; Department of Pediatrics (G.L.C., H.C.M.), Division of Genetic Medicine, University of Washington, Seattle; Florey Institute of Neuroscience and Mental Health (S.A.M., I.E.S.), Melbourne, Australia; Departments of Radiology and Paediatrics (S.A.M., I.E.S.), Royal Children's Hospital, and University of Melbourne, Australia; Carol Davila University of Medicine (D.C.), Pediatric Neurology Clinic, Al Obregia Hospital, Bucharest, Romania; and TY Nelson Department of Neurology (D.S.G.), The Children's Hospital at Westmead, Sydney, Australia.
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Song MY, Tian FF, Wang YZ, Huang X, Guo JL, Ding DX. Potential roles of the RGMa-FAK-Ras pathway in hippocampal mossy fiber sprouting in the pentylenetetrazole kindling model. Mol Med Rep 2014; 11:1738-44. [PMID: 25420768 PMCID: PMC4270322 DOI: 10.3892/mmr.2014.2993] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2014] [Accepted: 08/01/2014] [Indexed: 11/23/2022] Open
Abstract
Mossy fiber sprouting (MFS) is a unique feature of chronic epilepsy. However, the molecular signals underlying MFS are still unclear. The repulsive guidance molecule A (RGMa) appears to contribute to axon growth and axonal guidance, and may exert its biological effects by dephosphorylating focal adhesion kinase (FAK) at Tyr397, then regulating the activation of Ras. The objective of this study was to explore the expression patterns of RGMa, FAK (Tyr397) and Ras in epileptogenesis, and their correlation with MFS. The epileptic models were established by intraperitoneal pentylenetetrazole (PTZ) injection of Sprague-Dawley rats. At 3 days and at 1, 2, 4 and 6 weeks after the first PTZ injection, Timm staining was scored at different time points in the CA3 region of the hippocampus and dentate gyrus. The protein levels of RGMa, FAK (Tyr397) and Ras were analyzed at different time points in the CA3 region of the hippocampus using immunofluorescence, immunohistochemistry and western blot analysis. Compared with the control (saline-injected) group, the expression of RGMa in the CA3 area was significantly downregulated (P<0.05) from 3 days and still maintained the low expression at 6 weeks in the PTZ group. The expression of FAK (Tyr397) and Ras was upregulated (P<0.05) in the PTZ groups. The Timm score in the CA3 region was significantly higher than that in the control group at different time points and reached a peak at 4 weeks. In the CA3 region, no obvious distinction was observed at the different time points in the control group. To the best of our knowledge, these are the first results to indicate that the RGMa-FAK-Ras pathway may be involved in MFS and the development of temporal lobe epilepsy.
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Affiliation(s)
- Ming-Yu Song
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Fa-Fa Tian
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Yu-Zhong Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Xia Huang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Jia-Ling Guo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
| | - Dong-Xue Ding
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, P.R. China
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33
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15q26.1 microdeletion encompassing only CHD2 and RGMA in two adults with moderate intellectual disability, epilepsy and truncal obesity. Eur J Med Genet 2014; 57:520-3. [PMID: 24932903 DOI: 10.1016/j.ejmg.2014.06.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 06/02/2014] [Indexed: 01/28/2023]
Abstract
We report two patients with microdeletions in chromosomal subdomain 15q26.1 encompassing only two genes, CHD2 and RGMA. Both patients present a distinct phenotype with intellectual disability, epilepsy, behavioral issues, truncal obesity, scoliosis and facial dysmorphism. CHD2 haploinsufficiency is known to cause intellectual disability and epilepsy, RGMA haploinsufficiency might explain truncal obesity with onset around puberty observed in our two patients.
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Chénier S, Yoon G, Argiropoulos B, Lauzon J, Laframboise R, Ahn JW, Ogilvie CM, Lionel AC, Marshall CR, Vaags AK, Hashemi B, Boisvert K, Mathonnet G, Tihy F, So J, Scherer SW, Lemyre E, Stavropoulos DJ. CHD2 haploinsufficiency is associated with developmental delay, intellectual disability, epilepsy and neurobehavioural problems. J Neurodev Disord 2014; 6:9. [PMID: 24834135 PMCID: PMC4022362 DOI: 10.1186/1866-1955-6-9] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Accepted: 04/03/2014] [Indexed: 11/10/2022] Open
Abstract
Background The chromodomain helicase DNA binding domain (CHD) proteins modulate gene expression via their ability to remodel chromatin structure and influence histone acetylation. Recent studies have shown that CHD2 protein plays a critical role in embryonic development, tumor suppression and survival. Like other genes encoding members of the CHD family, pathogenic mutations in the CHD2 gene are expected to be implicated in human disease. In fact, there is emerging evidence suggesting that CHD2 might contribute to a broad spectrum of neurodevelopmental disorders. Despite growing evidence, a description of the full phenotypic spectrum of this condition is lacking. Methods We conducted a multicentre study to identify and characterise the clinical features associated with haploinsufficiency of CHD2. Patients with deletions of this gene were identified from among broadly ascertained clinical cohorts undergoing genomic microarray analysis for developmental delay, congenital anomalies and/or autism spectrum disorder. Results Detailed clinical assessments by clinical geneticists showed recurrent clinical symptoms, including developmental delay, intellectual disability, epilepsy, behavioural problems and autism-like features without characteristic facial gestalt or brain malformations observed on magnetic resonance imaging scans. Parental analysis showed that the deletions affecting CHD2 were de novo in all four patients, and analysis of high-resolution microarray data derived from 26,826 unaffected controls showed no deletions of this gene. Conclusions The results of this study, in addition to our review of the literature, support a causative role of CHD2 haploinsufficiency in developmental delay, intellectual disability, epilepsy and behavioural problems, with phenotypic variability between individuals.
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Affiliation(s)
- Sébastien Chénier
- Division of Medical Genetics, Department of Pediatrics, Centre Hospitalier Universitaire de Sherbrooke, 3001, 12E Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Grace Yoon
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for Sick Children and University of Toronto, 555 University Ave, Toronto, ON M5G 1X8, Canada
| | - Bob Argiropoulos
- Department of Medical Genetics, Alberta Children's Hospital Research Institute, University of Calgary, 2888 Shaganappi Trail NW, Calgary, AB T3B 6A8, Canada
| | - Julie Lauzon
- Department of Medical Genetics, Alberta Children's Hospital Research Institute, University of Calgary, 2888 Shaganappi Trail NW, Calgary, AB T3B 6A8, Canada
| | - Rachel Laframboise
- Division of Medical Genetics, Department of Pediatrics, Centre Hospitalier Universitaire de Québec, 2705 Boulevard Laurier, Québec, QC G1V 4G2, Canada
| | - Joo Wook Ahn
- Cytogenetics Department, Guy's and St Thomas' NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK
| | - Caroline Mackie Ogilvie
- Cytogenetics Department, Guy's and St Thomas' NHS Foundation Trust, Great Maze Pond, London SE1 9RT, UK
| | - Anath C Lionel
- Department of Molecular Genetics and McLaughlin Centre, The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children and University of Toronto, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Christian R Marshall
- Department of Molecular Genetics and McLaughlin Centre, The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children and University of Toronto, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Andrea K Vaags
- Division of Anatomic Pathology and Cytopathology, Cytogenetics Laboratory, Calgary Laboratory Service and Alberta Children's Hospital, 2888 Shaganappi Trail NW, Calgary, AB T3B 6A8, Canada
| | - Bita Hashemi
- Division of Clinical and Metabolic Genetics, Department of Pediatrics, The Hospital for Sick Children and University of Toronto, 555 University Ave, Toronto, ON M5G 1X8, Canada
| | - Karine Boisvert
- Division of Medical Genetics, Department of Pediatrics, Centre Hospitalier Universitaire de Québec, 2705 Boulevard Laurier, Québec, QC G1V 4G2, Canada
| | - Géraldine Mathonnet
- Division of Medical Genetics, Department of Pediatrics, Centre Hospitalier Universitaire de Sainte-Justine, Université de Montréal, 3175, Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1C5, Canada
| | - Frédérique Tihy
- Division of Medical Genetics, Department of Pediatrics, Centre Hospitalier Universitaire de Sainte-Justine, Université de Montréal, 3175, Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1C5, Canada
| | - Joyce So
- Department of Clinical Genetics, Lakeridge Health Oshawa, 1 Hospital Court, Oshawa, ON L1G 2B9, Canada
| | - Stephen W Scherer
- Department of Molecular Genetics and McLaughlin Centre, The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children and University of Toronto, 686 Bay Street, Toronto, ON M5G 0A4, Canada
| | - Emmanuelle Lemyre
- Division of Medical Genetics, Department of Pediatrics, Centre Hospitalier Universitaire de Sainte-Justine, Université de Montréal, 3175, Chemin de la Côte-Sainte-Catherine, Montréal, QC H3T 1C5, Canada
| | - Dimitri J Stavropoulos
- Department of Paediatric Laboratory Medicine, The Hospital for Sick Children and University of Toronto, 555 University Avenue, Toronto, ON M5G 1X8, Canada
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Lund C, Brodtkorb E, Øye AM, Røsby O, Selmer KK. CHD2 mutations in Lennox-Gastaut syndrome. Epilepsy Behav 2014; 33:18-21. [PMID: 24614520 DOI: 10.1016/j.yebeh.2014.02.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 02/03/2014] [Accepted: 02/03/2014] [Indexed: 12/19/2022]
Abstract
Lennox-Gastaut syndrome (LGS) is an epileptic encephalopathy with a heterogeneous etiology. In this study, we aimed to explore the role of CHD2 in LGS, as CHD2 mutations have been described recently in various epileptic encephalopathies. We have previously identified one patient with a large deletion affecting the CHD2 gene in a group of 22 patients with LGS or LGS-like epilepsy. In the remaining 17 patients without known etiology, Sanger sequencing revealed a de novo 1-bp duplication in the CHD2 gene in another patient. This mutation leads to a frameshift and, consequently, a premature stop codon 49bp downstream of the mutation. The patient had prominent myoclonic seizures and photosensitivity, thus, sharing phenotypic features with previously reported patients with CHD2-related epilepsy. In our original material of 22 patients with LGS features, we have now found two (9%) with mutations in the CHD2 gene. Our findings suggest that CHD2 mutations are important in the etiological spectrum of LGS.
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Affiliation(s)
- Caroline Lund
- National Centre for Rare Epilepsy-related Disorders, Oslo University Hospital, Oslo, Norway; National Centre for Epilepsy, SSE, Oslo University Hospital, Oslo, Norway.
| | - Eylert Brodtkorb
- Department of Neurology and Clinical Neurophysiology, St. Olav's Hospital, Trondheim, Norway; Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway
| | - Ane-Marte Øye
- Department of Medical Genetics, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Oddveig Røsby
- Department of Medical Genetics, Oslo University Hospital, University of Oslo, Oslo, Norway
| | - Kaja Kristine Selmer
- National Centre for Rare Epilepsy-related Disorders, Oslo University Hospital, Oslo, Norway; Department of Medical Genetics, Oslo University Hospital, University of Oslo, Oslo, Norway
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O'Leary C, Cole SJ, Langford M, Hewage J, White A, Cooper HM. RGMa regulates cortical interneuron migration and differentiation. PLoS One 2013; 8:e81711. [PMID: 24312340 PMCID: PMC3842424 DOI: 10.1371/journal.pone.0081711] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 10/23/2013] [Indexed: 11/24/2022] Open
Abstract
The etiology of neuropsychiatric disorders, including schizophrenia and autism, has been linked to a failure to establish the intricate neural network comprising excitatory pyramidal and inhibitory interneurons during neocortex development. A large proportion of cortical inhibitory interneurons originate in the medial ganglionic eminence (MGE) of the ventral telencephalon and then migrate through the ventral subventricular zone, across the corticostriatal junction, into the embryonic cortex. Successful navigation of newborn interneurons through the complex environment of the ventral telencephalon is governed by spatiotemporally restricted deployment of both chemorepulsive and chemoattractive guidance cues which work in concert to create a migratory corridor. Despite the expanding list of interneuron guidance cues, cues responsible for preventing interneurons from re-entering the ventricular zone of the ganglionic eminences have not been well characterized. Here we provide evidence that the chemorepulsive axon guidance cue, RGMa (Repulsive Guidance Molecule a), may fulfill this function. The ventricular zone restricted expression of RGMa in the ganglionic eminences and the presence of its receptor, Neogenin, in the ventricular zone and on newborn and maturing MGE-derived interneurons implicates RGMa-Neogenin interactions in interneuron differentiation and migration. Using an in vitro approach, we show that RGMa promotes interneuron differentiation by potentiating neurite outgrowth. In addition, using in vitro explant and migration assays, we provide evidence that RGMa is a repulsive guidance cue for newborn interneurons migrating out of the ganglionic eminence ventricular zone. Intriguingly, the alternative Neogenin ligand, Netrin-1, had no effect on migration. However, we observed complete abrogation of RGMa-induced chemorepulsion when newborn interneurons were simultaneously exposed to RGMa and Netrin-1 gradients, suggesting a novel mechanism for the tight regulation of RGMa-guided interneuron migration. We propose that during peak neurogenesis, repulsive RGMa-Neogenin interactions drive interneurons into the migratory corridor and prevent re-entry into the ventricular zone of the ganglionic eminences.
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Affiliation(s)
- Conor O'Leary
- The University of Queensland, Queensland Brain Institute, Brisbane, Queensland, Australia
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Suls A, Jaehn JA, Kecskés A, Weber Y, Weckhuysen S, Craiu DC, Siekierska A, Djémié T, Afrikanova T, Gormley P, von Spiczak S, Kluger G, Iliescu CM, Talvik T, Talvik I, Meral C, Caglayan HS, Giraldez BG, Serratosa J, Lemke JR, Hoffman-Zacharska D, Szczepanik E, Barisic N, Komarek V, Hjalgrim H, Møller RS, Linnankivi T, Dimova P, Striano P, Zara F, Marini C, Guerrini R, Depienne C, Baulac S, Kuhlenbäumer G, Crawford AD, Lehesjoki AE, de Witte PAM, Palotie A, Lerche H, Esguerra CV, De Jonghe P, Helbig I. De novo loss-of-function mutations in CHD2 cause a fever-sensitive myoclonic epileptic encephalopathy sharing features with Dravet syndrome. Am J Hum Genet 2013; 93:967-75. [PMID: 24207121 DOI: 10.1016/j.ajhg.2013.09.017] [Citation(s) in RCA: 144] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 05/28/2013] [Accepted: 09/30/2013] [Indexed: 11/18/2022] Open
Abstract
Dravet syndrome is a severe epilepsy syndrome characterized by infantile onset of therapy-resistant, fever-sensitive seizures followed by cognitive decline. Mutations in SCN1A explain about 75% of cases with Dravet syndrome; 90% of these mutations arise de novo. We studied a cohort of nine Dravet-syndrome-affected individuals without an SCN1A mutation (these included some atypical cases with onset at up to 2 years of age) by using whole-exome sequencing in proband-parent trios. In two individuals, we identified a de novo loss-of-function mutation in CHD2 (encoding chromodomain helicase DNA binding protein 2). A third CHD2 mutation was identified in an epileptic proband of a second (stage 2) cohort. All three individuals with a CHD2 mutation had intellectual disability and fever-sensitive generalized seizures, as well as prominent myoclonic seizures starting in the second year of life or later. To explore the functional relevance of CHD2 haploinsufficiency in an in vivo model system, we knocked down chd2 in zebrafish by using targeted morpholino antisense oligomers. chd2-knockdown larvae exhibited altered locomotor activity, and the epileptic nature of this seizure-like behavior was confirmed by field-potential recordings that revealed epileptiform discharges similar to seizures in affected persons. Both altered locomotor activity and epileptiform discharges were absent in appropriate control larvae. Our study provides evidence that de novo loss-of-function mutations in CHD2 are a cause of epileptic encephalopathy with generalized seizures.
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Affiliation(s)
- Arvid Suls
- Neurogenetics group, Department of Molecular Genetics, VIB, 2610 Antwerp, Belgium; Laboratory of Neurogenetics, Institute Born-Bunge, University of Antwerp, 2610 Antwerp, Belgium
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Carvill GL, Heavin SB, Yendle SC, McMahon JM, O’Roak BJ, Cook J, Khan A, Dorschner MO, Weaver M, Calvert S, Malone S, Wallace G, Stanley T, Bye AME, Bleasel A, Howell KB, Kivity S, Mackay MT, Rodriguez-Casero V, Webster R, Korczyn A, Afawi Z, Zelnick N, Lerman-Sagie T, Lev D, Møller RS, Gill D, Andrade DM, Freeman JL, Sadleir LG, Shendure J, Berkovic SF, Scheffer IE, Mefford HC. Targeted resequencing in epileptic encephalopathies identifies de novo mutations in CHD2 and SYNGAP1. Nat Genet 2013; 45:825-30. [PMID: 23708187 PMCID: PMC3704157 DOI: 10.1038/ng.2646] [Citation(s) in RCA: 460] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 05/01/2013] [Indexed: 12/16/2022]
Abstract
Epileptic encephalopathies are a devastating group of epilepsies with poor prognosis, of which the majority are of unknown etiology. We perform targeted massively parallel resequencing of 19 known and 46 candidate genes for epileptic encephalopathy in 500 affected individuals (cases) to identify new genes involved and to investigate the phenotypic spectrum associated with mutations in known genes. Overall, we identified pathogenic mutations in 10% of our cohort. Six of the 46 candidate genes had 1 or more pathogenic variants, collectively accounting for 3% of our cohort. We show that de novo CHD2 and SYNGAP1 mutations are new causes of epileptic encephalopathies, accounting for 1.2% and 1% of cases, respectively. We also expand the phenotypic spectra explained by SCN1A, SCN2A and SCN8A mutations. To our knowledge, this is the largest cohort of cases with epileptic encephalopathies to undergo targeted resequencing. Implementation of this rapid and efficient method will change diagnosis and understanding of the molecular etiologies of these disorders.
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Affiliation(s)
- Gemma L. Carvill
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
| | - Sinéad B. Heavin
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Simone C. Yendle
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Jacinta M. McMahon
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Brian J. O’Roak
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98195, USA
| | - Joseph Cook
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
| | - Adiba Khan
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
| | - Michael O Dorschner
- Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, Washington, 98195, USA
- Veteran Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Molly Weaver
- Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, Washington, 98195, USA
- Veteran Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Sophie Calvert
- Neurosciences Children’s Health Queensland, Royal and Mater Children’s Hospitals, Brisbane, Queensland, Australia
| | - Stephen Malone
- Neurosciences Children’s Health Queensland, Royal and Mater Children’s Hospitals, Brisbane, Queensland, Australia
| | - Geoffrey Wallace
- Neurosciences Children’s Health Queensland, Royal and Mater Children’s Hospitals, Brisbane, Queensland, Australia
| | - Thorsten Stanley
- Department of Paediatrics, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
| | - Ann M. E. Bye
- Department of Paediatric Neurology, University of New South Wales, Sydney Children’s Hospital, Sydney, New South Wales, Australia
| | - Andrew Bleasel
- Westmead Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Katherine B. Howell
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
| | - Sara Kivity
- Epilepsy Unit, Schneider Children’s Medical Center of Israel, Petach Tikvah, Israel
| | - Mark T. Mackay
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
- Critical Care & Neurosciences Theme, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | | | - Richard Webster
- TY Nelson Department of Neurology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Amos Korczyn
- Department of Neurology, Tel-Aviv University, Tel-Aviv, Israel
| | - Zaid Afawi
- Tel-Aviv University Medical School, Tel-Aviv, Israel
| | - Nathanel Zelnick
- Department of Pediatrics, Carmel Medical Center, Technion Faculty of Medicine, Haifa, Israel
| | - Tally Lerman-Sagie
- Metabolic-Neurogenetic Service, Wolfson Medical Center, Holon, and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Dorit Lev
- Metabolic-Neurogenetic Service, Wolfson Medical Center, Holon, and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Deepak Gill
- TY Nelson Department of Neurology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Danielle M. Andrade
- Division of Neurology, Department of Medicine, University of Toronto, Toronto Western Hospital, Krembil Neurosciences Program. Toronto, Canada
| | - Jeremy L. Freeman
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
- Critical Care & Neurosciences Theme, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Lynette G. Sadleir
- Department of Paediatrics, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98195, USA
| | - Samuel F. Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Ingrid E. Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Florey Institute, Melbourne, Victoria, Australia
| | - Heather C. Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
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