51
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Hong SJ, Bernhardt BC, Gill RS, Bernasconi N, Bernasconi A. The spectrum of structural and functional network alterations in malformations of cortical development. Brain 2017; 140:2133-2143. [DOI: 10.1093/brain/awx145] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/07/2017] [Indexed: 12/28/2022] Open
Affiliation(s)
- Seok-Jun Hong
- Neuroimaging of Epilepsy Laboratory, Department of Neurology and McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Boris C Bernhardt
- Neuroimaging of Epilepsy Laboratory, Department of Neurology and McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Ravnoor S Gill
- Neuroimaging of Epilepsy Laboratory, Department of Neurology and McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Neda Bernasconi
- Neuroimaging of Epilepsy Laboratory, Department of Neurology and McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
| | - Andrea Bernasconi
- Neuroimaging of Epilepsy Laboratory, Department of Neurology and McConnell Brain Imaging Centre, Montreal Neurological Institute and Hospital, McGill University, Montreal, Quebec, Canada
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52
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A novel missense mutation in the HECT domain of NEDD4L identified in a girl with periventricular nodular heterotopia, polymicrogyria and cleft palate. J Hum Genet 2017; 62:861-863. [DOI: 10.1038/jhg.2017.53] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 04/18/2017] [Accepted: 04/20/2017] [Indexed: 02/02/2023]
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53
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McConnell MJ, Moran JV, Abyzov A, Akbarian S, Bae T, Cortes-Ciriano I, Erwin JA, Fasching L, Flasch DA, Freed D, Ganz J, Jaffe AE, Kwan KY, Kwon M, Lodato MA, Mills RE, Paquola ACM, Rodin RE, Rosenbluh C, Sestan N, Sherman MA, Shin JH, Song S, Straub RE, Thorpe J, Weinberger DR, Urban AE, Zhou B, Gage FH, Lehner T, Senthil G, Walsh CA, Chess A, Courchesne E, Gleeson JG, Kidd JM, Park PJ, Pevsner J, Vaccarino FM. Intersection of diverse neuronal genomes and neuropsychiatric disease: The Brain Somatic Mosaicism Network. Science 2017; 356:356/6336/eaal1641. [PMID: 28450582 DOI: 10.1126/science.aal1641] [Citation(s) in RCA: 172] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Neuropsychiatric disorders have a complex genetic architecture. Human genetic population-based studies have identified numerous heritable sequence and structural genomic variants associated with susceptibility to neuropsychiatric disease. However, these germline variants do not fully account for disease risk. During brain development, progenitor cells undergo billions of cell divisions to generate the ~80 billion neurons in the brain. The failure to accurately repair DNA damage arising during replication, transcription, and cellular metabolism amid this dramatic cellular expansion can lead to somatic mutations. Somatic mutations that alter subsets of neuronal transcriptomes and proteomes can, in turn, affect cell proliferation and survival and lead to neurodevelopmental disorders. The long life span of individual neurons and the direct relationship between neural circuits and behavior suggest that somatic mutations in small populations of neurons can significantly affect individual neurodevelopment. The Brain Somatic Mosaicism Network has been founded to study somatic mosaicism both in neurotypical human brains and in the context of complex neuropsychiatric disorders.
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54
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Abstract
INTRODUCTION Dishevelled, Egl-10 and Pleckstrin (DEP) domain-containing protein 5 (DEPDC5) is a protein subunit of the GTPase-activating proteins towards Rags 1 (GATOR1) complex. GATOR1 is a recently identified modulator of mechanistic target of rapamycin (mTOR) activity. mTOR is a key regulator of cell proliferation and metabolism; disruption of the mTOR pathway is implicated in focal epilepsy, both acquired and genetic. Tuberous sclerosis is the prototypic mTOR genetic syndrome with epilepsy, however GATOR1 gene mutations have recently been shown to cause lesional and non-lesional focal epilepsy. Areas covered: This review summarizes the mTOR pathway, including regulators and downstream effectors, emphasizing recent developments in the understanding of the complex role of the GATOR1 complex. We review the epilepsy types associated with mTOR overactivity, including tuberous sclerosis, polyhydramnios megalencephaly symptomatic epilepsy, cortical dysplasia, non-lesional focal epilepsy and post-traumatic epilepsy. Currently available mTOR inhibitors are discussed, primarily rapamycin analogs and ATP competitive mTOR inhibitors. Expert opinion: DEPDC5 is an attractive therapeutic target in focal epilepsy, as effects of DEPDC5 agonists would likely be anti-epileptogenic and more selective than currently available mTOR inhibitors. Therapeutic effects might be synergistic with certain existing dietary therapies, including the ketogenic diet.
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Affiliation(s)
- Kenneth A Myers
- a Epilepsy Research Centre, Department of Medicine , The University of Melbourne, Austin Health , Heidelberg , Victoria , Australia.,b Department of Paediatrics , Royal Children's Hospital, The University of Melbourne , Flemington , Victoria , Australia
| | - Ingrid E Scheffer
- a Epilepsy Research Centre, Department of Medicine , The University of Melbourne, Austin Health , Heidelberg , Victoria , Australia.,b Department of Paediatrics , Royal Children's Hospital, The University of Melbourne , Flemington , Victoria , Australia.,c The Florey Institute of Neuroscience and Mental Health , Heidelberg , Victoria , Australia
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55
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Abstract
This review is a summary of a talk presented at the 2015 American Epilepsy Society Annual Meeting. Its purposes are 1) to review developments in epilepsy genetics, 2) to discuss which groups of patients with epilepsy might benefit from genetic testing, and 3) to present a rational approach to genetic testing in epilepsy in the rapidly evolving era of genomic medicine.
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56
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Lungu M, Romila A, Hangan L, Caraban B. Schizencephaly Associated with Polymicrogirya – Cause for Late-Onset Epileptic Seizures in Adult. A Case Report. ARS MEDICA TOMITANA 2016. [DOI: 10.1515/arsm-2016-0039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
The article presents the case of a 61-year old female patient, with no history of neurological illness, who presents a rapid onset of two convulsive seizures, triggered by a psychological trauma. The first convulsive seizure is repeated within 24 hours.
The general, as well as the neurological clinical examination have not found any pathological signs. MRI scanning of the brain pointed to right-parietal schizencephaly, associated with polymicrogyria, the believed causes of the epileptic seizures.
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Affiliation(s)
- Mihaela Lungu
- Neurological Department, Emergency Clinical Hospital, Galati; Faculty of Medicine and Pharmacy, “Dunarea de Jos” University of Galati
| | - Aurelia Romila
- Geriatric Department, Emergency Clinical Hospital, Galati; Faculty of Medicine and Pharmacy, “Dunarea de Jos” University of Galati, Center for Research on Medical-Pharmaceutical
| | - L.T. Hangan
- Faculty of Medicine, University “Ovidius” of Constanta
| | - B.M. Caraban
- Faculty of Medicine, University “Ovidius” of Constanta
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57
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Mutations in the HECT domain of NEDD4L lead to AKT-mTOR pathway deregulation and cause periventricular nodular heterotopia. Nat Genet 2016; 48:1349-1358. [PMID: 27694961 PMCID: PMC5086093 DOI: 10.1038/ng.3676] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Accepted: 08/24/2016] [Indexed: 12/16/2022]
Abstract
Neurodevelopmental disorders with periventricular nodular heterotopia (PNH) are etiologically heterogeneous, and their genetic causes remain in many cases unknown. Here we show that missense mutations in NEDD4L mapping to the HECT domain of the encoded E3 ubiquitin ligase lead to PNH associated with toe syndactyly, cleft palate and neurodevelopmental delay. Cellular and expression data showed sensitivity of PNH-associated mutants to proteasome degradation. Moreover, an in utero electroporation approach showed that PNH-related mutants and excess wild-type NEDD4L affect neurogenesis, neuronal positioning and terminal translocation. Further investigations, including rapamycin-based experiments, found differential deregulation of pathways involved. Excess wild-type NEDD4L leads to disruption of Dab1 and mTORC1 pathways, while PNH-related mutations are associated with deregulation of mTORC1 and AKT activities. Altogether, these data provide insights into the critical role of NEDD4L in the regulation of mTOR pathways and their contributions in cortical development.
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58
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Abstract
Malformations of cortical development (MCD) represent a major cause of developmental disabilities, severe epilepsy, and reproductive disadvantage. Genes that have been associated to MCD are mainly involved in cell proliferation and specification, neuronal migration, and late cortical organization. Lissencephaly-pachygyria-severe band heterotopia are diffuse neuronal migration disorders causing severe global neurological impairment. Abnormalities of the LIS1, DCX, ARX, RELN, VLDLR, ACTB, ACTG1, TUBG1, KIF5C, KIF2A, and CDK5 genes have been associated with these malformations. More recent studies have also established a relationship between lissencephaly, with or without associated microcephaly, corpus callosum dysgenesis as well as cerebellar hypoplasia, and at times, a morphological pattern consistent with polymicrogyria with mutations of several genes (TUBA1A, TUBA8, TUBB, TUBB2B, TUBB3, and DYNC1H1), regulating the synthesis and function of microtubule and centrosome key components and hence defined as tubulinopathies. MCD only affecting subsets of neurons, such as mild subcortical band heterotopia and periventricular heterotopia, have been associated with abnormalities of the DCX, FLN1A, and ARFGEF2 genes and cause neurological and cognitive impairment that vary from severe to mild deficits. Polymicrogyria results from abnormal late cortical organization and is inconstantly associated with abnormal neuronal migration. Localized polymicrogyria has been associated with anatomo-specific deficits, including disorders of language and higher cognition. Polymicrogyria is genetically heterogeneous, and only in a small minority of patients, a definite genetic cause has been identified. Megalencephaly with normal cortex or polymicrogyria by MRI imaging, hemimegalencephaly and focal cortical dysplasia can all result from mutations in genes of the PI3K-AKT-mTOR pathway. Postzygotic mutations have been described for most MCD and can be limited to the dysplastic tissue in the less diffuse forms.
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Affiliation(s)
- Elena Parrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Department of Neuroscience, A. Meyer Children's Hospital, University of Florence, Florence, Italy
| | - Valerio Conti
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Department of Neuroscience, A. Meyer Children's Hospital, University of Florence, Florence, Italy
| | - William B Dobyns
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, and Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Wash., USA
| | - Renzo Guerrini
- Pediatric Neurology, Neurogenetics and Neurobiology Unit and Laboratories, Department of Neuroscience, A. Meyer Children's Hospital, University of Florence, Florence, Italy
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59
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Eckert MA, Berninger VW, Hoeft F, Vaden KI. A case of Bilateral Perisylvian Syndrome with reading disability. Cortex 2016; 76:121-4. [PMID: 26861558 PMCID: PMC4776332 DOI: 10.1016/j.cortex.2016.01.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Revised: 12/23/2015] [Accepted: 01/05/2016] [Indexed: 12/21/2022]
Affiliation(s)
- Mark A Eckert
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, Charleston, SC, United States.
| | - Virginia W Berninger
- Department of Educational Psychology, University of Washington, Seattle, WA, United States
| | - Fumiko Hoeft
- Department of Psychiatry, University of California San Francisco, San Francisco, CA, United States
| | - Kenneth I Vaden
- Department of Otolaryngology - Head and Neck Surgery, Medical University of South Carolina, Charleston, SC, United States
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60
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Terrone G, Voisin N, Abdullah Alfaiz A, Cappuccio G, Vitiello G, Guex N, D'Amico A, James Barkovich A, Brunetti-Pierri N, Del Giudice E, Reymond A. De novo PIK3R2 variant causes polymicrogyria, corpus callosum hyperplasia and focal cortical dysplasia. Eur J Hum Genet 2016; 24:1359-62. [PMID: 26860062 DOI: 10.1038/ejhg.2016.7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/08/2015] [Accepted: 12/16/2015] [Indexed: 11/09/2022] Open
Abstract
We report an 8-year-old boy with a complex cerebral malformation, intellectual disability, and complex partial seizures. Whole-exome sequencing revealed a yet unreported de novo variant in the PIK3R2 gene that was recently associated with megalencephaly-polymicrogyria-polydactyly-hydrocephalus (MPPH) syndrome and bilateral perisylvian polymicrogyria (BPP). Our patient showed cerebral abnormalities (megalencephaly, perisylvian polymicrogyria, and mega corpus callosum) that were consistent with these conditions. Imaging also showed right temporal anomalies suggestive of cortical dysplasia. Until now, only three variants (c.1117G>A (p.(G373R)), c.1126A>G (p.(K376E)) and c.1202T>C (p.(L401P))) affecting the SH2 domain of the PIK3R2 protein have been reported in MPPH and BPP syndromes. In contrast to the variants reported so far, the patient described herein exhibits the c.1669G>C (p.(D557H)) variant that affects a highly conserved residue at the interface with the PI3K catalytic subunit α. The phenotypic spectrum associated with variants in this gene and its pathway are likely to continue to expand as more cases are identified.
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Affiliation(s)
- Gaetano Terrone
- Department of Translational Medicine, Section of Pediatrics, Federico II University, Naples, Italy
| | - Norine Voisin
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Ali Abdullah Alfaiz
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland.,Bioinformatics Section, King Abdullah International Medical Research Center (KAIMRC), Riyadh, Kingdom of Saudi Arabia.,King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Kingdom of Saudi Arabia
| | - Gerarda Cappuccio
- Department of Translational Medicine, Section of Pediatrics, Federico II University, Naples, Italy
| | - Giuseppina Vitiello
- Department of Translational Medicine, Section of Pediatrics, Federico II University, Naples, Italy
| | - Nicolas Guex
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland.,Swiss Institute of Bioinformatics (SIB), Lausanne, Switzerland
| | - Alessandra D'Amico
- Department of Diagnostic Imaging, Neuroradiology Unit, Federico II University, Naples, Italy
| | - A James Barkovich
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA
| | - Nicola Brunetti-Pierri
- Department of Translational Medicine, Section of Pediatrics, Federico II University, Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy
| | - Ennio Del Giudice
- Department of Translational Medicine, Section of Pediatrics, Federico II University, Naples, Italy
| | - Alexandre Reymond
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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61
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Scheffer IE. PIK-ing the right gene for polymicrogyria. Lancet Neurol 2015; 14:1147-8. [PMID: 26520803 DOI: 10.1016/s1474-4422(15)00305-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 10/20/2015] [Indexed: 10/22/2022]
Affiliation(s)
- Ingrid E Scheffer
- Florey Institute, University of Melbourne, Austin Health and Royal Children's Hospital, Melbourne, VIC, Australia.
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