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Dennys CN, Vermudez SAD, Deacon RJM, Sierra-Delgado JA, Rich K, Zhang X, Buch A, Weiss K, Moxley Y, Rajpal H, Espinoza FD, Powers S, Ávila AS, Gogliotti RG, Cogram P, Niswender CM, Meyer KC. MeCP2 gene therapy ameliorates disease phenotype in mouse model for Pitt Hopkins syndrome. Neurotherapeutics 2024:e00376. [PMID: 38876822 DOI: 10.1016/j.neurot.2024.e00376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 05/07/2024] [Accepted: 05/14/2024] [Indexed: 06/16/2024] Open
Abstract
The neurodevelopmental disorder Pitt Hopkins syndrome (PTHS) causes clinical symptoms similar to Rett syndrome (RTT) patients. However, RTT is caused by MECP2 mutations whereas mutations in the TCF4 gene lead to PTHS. The mechanistic commonalities underling these two disorders are unknown, but their shared symptomology suggest that convergent pathway-level disruption likely exists. We reprogrammed patient skin derived fibroblasts into induced neuronal progenitor cells. Interestingly, we discovered that MeCP2 levels were decreased in PTHS patient iNPCs relative to healthy controls and that both iNPCs and iAstrocytes displayed defects in function and differentiation in a mutation-specific manner. When Tcf4+/- mice were genetically crossed with mice overexpressing MeCP2, molecular and phenotypic defects were significantly ameliorated, underlining and important role of MeCP2 in PTHS pathology. Importantly, post-natal intracerebroventricular gene replacement therapy with adeno-associated viral vector serotype 9 (AAV9)-expressing MeCP2 (AAV9.P546.MeCP2) significantly improved iNPC and iAstrocyte function and effectively ameliorated histological and behavioral defects in Tcf4+/- mice. Combined, our data suggest a previously unknown role of MeCP2 in PTHS pathology and common pathways that might be affected in multiple neurodevelopmental disorders. Our work highlights potential novel therapeutic targets for PTHS, including upregulation of MeCP2 expression or its downstream targets or, potentially, MeCP2-based gene therapy.
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Affiliation(s)
- Cassandra N Dennys
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Sheryl Anne D Vermudez
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Robert J M Deacon
- Department of Genetics, Institute of Ecology and Biodiversity, Faculty of Science, University of Chile, Chile
| | - J Andrea Sierra-Delgado
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Kelly Rich
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Xiaojin Zhang
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Aditi Buch
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Kelly Weiss
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Yuta Moxley
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Hemangi Rajpal
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA
| | - Francisca D Espinoza
- Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, 4090541, Chile
| | - Samantha Powers
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Ariel S Ávila
- Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, 4090541, Chile
| | - Rocco G Gogliotti
- Department of Molecular Pharmacology and Neuroscience, Loyola University Chicago, Maywood, IL 60153, USA
| | - Patricia Cogram
- Department of Genetics, Institute of Ecology and Biodiversity, Faculty of Science, University of Chile, Chile
| | - Colleen M Niswender
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37232, USA; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kathrin C Meyer
- Center for Gene Therapy, The Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA; Department of Pediatrics, The Ohio State University Medical Center, Columbus, OH, USA; Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
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2
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Currò A, Doddato G, Bruttini M, Zollino M, Marangi G, Zappella M, Renieri A, Pinto AM. CDKL5 mutations may mimic Pitt-Hopkins syndrome phenotype. Eur J Med Genet 2020; 64:104102. [PMID: 33220470 DOI: 10.1016/j.ejmg.2020.104102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 10/30/2020] [Accepted: 11/08/2020] [Indexed: 11/28/2022]
Abstract
Genetic conditions comprise a wide spectrum of different phenotypes, rapidly expanding due to new diagnostic methodologies. Patients' facial features and clinical history represent the key elements leading clinicians to the right diagnosis. CDKL5-early onset epilepsy and Pitt-Hopkins syndrome are two well-known genetic conditions, with a defined phenotype sharing some common characteristics like early-onset epilepsy and hyperventilation episodes. Whilst facial features represent a diagnostic handle in patients with Pitt-Hopkins syndrome, clinical history is crucial in patients carrying a mutation in CDKL5. Here we present the clinical case of a girl evaluated for the first time when she was 24-years old, with a clinical phenotype mimicking Pitt-Hopkins syndrome. Her facial features have become coarser while she was growing up, leading geneticists to raise different clinical hypotheses and to perform several molecular tests before getting the diagnosis of CDKL5-early-epileptic encephalopathy. This finding highlights that although typical facial gestalt has not so far extensively been described in CDKL5 mutated adult patients, peculiar facial features could be present later in life and may let CDKL5-related disorder mimic Pitt Hopkins. Thus, considering atypical Rett syndrome in the differential diagnosis of Pitt Hopkins syndrome could be important to solve complex clinical cases.
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Affiliation(s)
- Aurora Currò
- Medical Genetics, University of Siena, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Gabriella Doddato
- Medical Genetics, University of Siena, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Mirella Bruttini
- Medical Genetics, University of Siena, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
| | - Marcella Zollino
- Università Cattolica del Sacro Cuore, Facoltà di Medicina e Chirurgia, Dipartimento Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Roma, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologico, Unità di Genetica Medica, Roma, Italy
| | - Giuseppe Marangi
- Università Cattolica del Sacro Cuore, Facoltà di Medicina e Chirurgia, Dipartimento Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Roma, Italy; Fondazione Policlinico Universitario A. Gemelli IRCCS, Dipartimento di Scienze di Laboratorio e Infettivologico, Unità di Genetica Medica, Roma, Italy
| | | | - Alessandra Renieri
- Medical Genetics, University of Siena, Siena, Italy; Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
| | - Anna Maria Pinto
- Genetica Medica, Azienda Ospedaliera Universitaria Senese, Siena, Italy
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3
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Kaur S, Van Bergen NJ, Ben-Zeev B, Leonardi E, Tan TY, Coman D, Kamien B, White SM, St John M, Phelan D, Rigbye K, Lim SC, Torres MC, Marty M, Savva E, Zhao T, Massey S, Murgia A, Gold WA, Christodoulou J. Expanding the genetic landscape of Rett syndrome to include lysine acetyltransferase 6A (KAT6A). J Genet Genomics 2020; 47:650-654. [PMID: 33386251 DOI: 10.1016/j.jgg.2020.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 09/21/2020] [Accepted: 09/23/2020] [Indexed: 10/23/2022]
Affiliation(s)
- Simranpreet Kaur
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Nicole J Van Bergen
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia
| | - Bruria Ben-Zeev
- Paediatric Neurology Institute, The Edmond and Lily Safra Paediatric Hospital, Sheba Medical Center, Tel HaShomer, Israel; Sackler School of Medicine, Tel Aviv University, Israel
| | - Emanuela Leonardi
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, Italy; Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padova, Italy
| | - Tiong Y Tan
- Department of Paediatrics, University of Melbourne, Melbourne, Australia; Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - David Coman
- Department of Paediatrics, The Wesley Hospital, Brisbane, Brisbane, Australia; Queensland Children's Hospital, Brisbane, Australia; School of Medicine, University of Queensland, Brisbane, Australia
| | - Benjamin Kamien
- Genetic Services of Western Australia, Western Australia, Australia; Faculty of Health and Medical Sciences, University of Western Australia, Australia
| | - Susan M White
- Department of Paediatrics, University of Melbourne, Melbourne, Australia; Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Miya St John
- Speech and Language, Murdoch Children's Research Institute, Parkville, Victoria, Australia; Department of Audiology and Speech Pathology, University of Melbourne, Parkville, Victoria, Australia
| | - Dean Phelan
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Kristin Rigbye
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Sze Chern Lim
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Michelle C Torres
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Melanie Marty
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Elena Savva
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Teresa Zhao
- Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia
| | - Sean Massey
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, Australia
| | - Alessandra Murgia
- Molecular Genetics of Neurodevelopment, Department of Woman and Child Health, University of Padova, Italy; Fondazione Istituto di Ricerca Pediatrica (IRP), Città della Speranza, Padova, Italy
| | - Wendy A Gold
- The University of Sydney, School of Medical Sciences and Discipline of Child and Adolescent Health, Faculty of Medicine and Health, Sydney, Australia; Molecular Neurobiology Lab, Kids Research, Westmead Children's Hospital, Westmead, Sydney, Australia; Kids Neuroscience Centre, Kids Research, Children's Hospital at Westmead, Westmead, Sydney, Australia
| | - John Christodoulou
- Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, Melbourne, Australia; Department of Paediatrics, University of Melbourne, Melbourne, Australia; Victorian Clinical Genetics Services, Murdoch Children's Research Institute, Melbourne, Australia; The University of Sydney, School of Medical Sciences and Discipline of Child and Adolescent Health, Faculty of Medicine and Health, Sydney, Australia.
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4
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Kaur S, Van Bergen NJ, Gold WA, Eggers S, Lunke S, White SM, Ellaway C, Christodoulou J. Whole exome sequencing reveals a de novo missense variant in EEF1A2 in a Rett syndrome-like patient. Clin Case Rep 2019; 7:2476-2482. [PMID: 31893083 PMCID: PMC6935606 DOI: 10.1002/ccr3.2511] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 09/19/2019] [Accepted: 09/30/2019] [Indexed: 01/09/2023] Open
Abstract
Using whole exome sequencing, we found a pathogenic variant in the EEF1A2 gene in a patient with a Rett syndrome-like (RTT-like) phenotype, further confirming the association between EEF1A2 and Rett syndrome RTT and RTT-like phenotypes.
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Affiliation(s)
- Simranpreet Kaur
- Brain and Mitochondrial Research GroupMurdoch Children's Research InstituteParkvilleVic.Australia
- Department of PaediatricsUniversity of MelbourneParkvilleVic.Australia
| | - Nicole J. Van Bergen
- Brain and Mitochondrial Research GroupMurdoch Children's Research InstituteParkvilleVic.Australia
- Department of PaediatricsUniversity of MelbourneParkvilleVic.Australia
| | - Wendy Anne Gold
- Molecular Neurobiology Lab, Kids ResearchWestmead Children's HospitalWestmeadNSWAustralia
- Disciplines of Genetic Medicine and Child and Adolescent HealthSydney Medical SchoolUniversity of SydneyNSWAustralia
| | - Stefanie Eggers
- Translational Genomics UnitMurdoch Children's Research InstituteParkvilleVic.Australia
- Victorian Clinical Genetics ServicesMurdoch Children's Research InstituteParkvilleVic.Australia
| | - Sebastian Lunke
- Translational Genomics UnitMurdoch Children's Research InstituteParkvilleVic.Australia
- Victorian Clinical Genetics ServicesMurdoch Children's Research InstituteParkvilleVic.Australia
| | - Susan M. White
- Department of PaediatricsUniversity of MelbourneParkvilleVic.Australia
- Victorian Clinical Genetics ServicesMurdoch Children's Research InstituteParkvilleVic.Australia
| | - Carolyn Ellaway
- Disciplines of Genetic Medicine and Child and Adolescent HealthSydney Medical SchoolUniversity of SydneyNSWAustralia
- Genetic Metabolic Disorders ServiceSydney Children's Hospital NetworkSydneyNSWAustralia
| | - John Christodoulou
- Brain and Mitochondrial Research GroupMurdoch Children's Research InstituteParkvilleVic.Australia
- Department of PaediatricsUniversity of MelbourneParkvilleVic.Australia
- Disciplines of Genetic Medicine and Child and Adolescent HealthSydney Medical SchoolUniversity of SydneyNSWAustralia
- Victorian Clinical Genetics ServicesMurdoch Children's Research InstituteParkvilleVic.Australia
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5
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Krishnaraj R, Haase F, Coorey B, Luca EJ, Wong I, Boyling A, Ellaway C, Christodoulou J, Gold WA. Genome-wide transcriptomic and proteomic studies of Rett syndrome mouse models identify common signaling pathways and cellular functions as potential therapeutic targets. Hum Mutat 2019; 40:2184-2196. [PMID: 31379106 DOI: 10.1002/humu.23887] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 07/27/2019] [Accepted: 07/31/2019] [Indexed: 12/13/2022]
Abstract
The discovery that Rett syndrome is caused by mutations in the MECP2 gene has provided a major breakthrough in our understanding of the disorder. However, despite this, there is still limited understanding of the underlying pathophysiology of the disorder hampering the development of curative treatments. Over the years, a number of animal models have been developed contributing to our knowledge of the role of MECP2 in development and improving our understanding of how subtle expression levels affect brain morphology and function. Transcriptomic and proteomic studies of animal models are useful in identifying perturbations in functional pathways and providing avenues for novel areas of research into disease. This review focuses on published transcriptomic and proteomic studies of mouse models of Rett syndrome with the aim of providing a summary of all the studies, the reported dysregulated genes and functional pathways that are found to be perturbed. The 36 articles identified highlighted a number of dysfunctional pathways as well as perturbed biological networks and cellular functions including synaptic dysfunction and neuronal transmission, inflammation, and mitochondrial dysfunction. These data reveal biological insights that contribute to the disease process which may be targeted to investigate curative treatments.
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Affiliation(s)
- Rahul Krishnaraj
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Florencia Haase
- Molecular Neurobiology Research Group, Kids Research, Sydney Children's Hospitals Network, Westmead, Australia
| | - Bronte Coorey
- Molecular Neurobiology Research Group, Kids Research, Sydney Children's Hospitals Network, Westmead, Australia
| | - Edward J Luca
- University Library, The University of Sydney, Sydney, New South Wales, Australia
| | - Ingar Wong
- Molecular Neurobiology Research Group, Kids Research, Sydney Children's Hospitals Network, Westmead, Australia
| | - Alexandra Boyling
- Molecular Neurobiology Research Group, Kids Research, Sydney Children's Hospitals Network, Westmead, Australia
| | - Carolyn Ellaway
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, The University of Sydney, Sydney, New South Wales, Australia.,Genetic Medicine, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia
| | - John Christodoulou
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Discipline of Child and Adolescent Health, The University of Sydney, Sydney, New South Wales, Australia.,Genetic Medicine, Sydney Medical School, The University of Sydney, Sydney, New South Wales, Australia.,Brain and Mitochondrial Research Group, Murdoch Children's Research Institute, and Department of Paediatrics, Melbourne Medical School, University of Melbourne, Melbourne, Victoria, Australia
| | - Wendy A Gold
- Genetic Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children's Hospital at Westmead, Sydney, New South Wales, Australia.,Molecular Neurobiology Research Group, Kids Research, Sydney Children's Hospitals Network, Westmead, Australia.,Discipline of Child and Adolescent Health, The University of Sydney, Sydney, New South Wales, Australia.,Kids Neuroscience Centre, The Children's Hospital at Westmead, Kids Research, Westmead, NSW, Australia
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6
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Babbi G, Martelli PL, Casadio R. PhenPath: a tool for characterizing biological functions underlying different phenotypes. BMC Genomics 2019; 20:548. [PMID: 31307376 PMCID: PMC6631446 DOI: 10.1186/s12864-019-5868-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Background Many diseases are associated with complex patterns of symptoms and phenotypic manifestations. Parsimonious explanations aim at reconciling the multiplicity of phenotypic traits with the perturbation of one or few biological functions. For this, it is necessary to characterize human phenotypes at the molecular and functional levels, by exploiting gene annotations and known relations among genes, diseases and phenotypes. This characterization makes it possible to implement tools for retrieving functions shared among phenotypes, co-occurring in the same patient and facilitating the formulation of hypotheses about the molecular causes of the disease. Results We introduce PhenPath, a new resource consisting of two parts: PhenPathDB and PhenPathTOOL. The former is a database collecting the human genes associated with the phenotypes described in Human Phenotype Ontology (HPO) and OMIM Clinical Synopses. Phenotypes are then associated with biological functions and pathways by means of NET-GE, a network-based method for functional enrichment of sets of genes. The present version considers only phenotypes related to diseases. PhenPathDB collects information for 18 OMIM Clinical synopses and 7137 HPO phenotypes, related to 4292 diseases and 3446 genes. Enrichment of Gene Ontology annotations endows some 87.7, 86.9 and 73.6% of HPO phenotypes with Biological Process, Molecular Function and Cellular Component terms, respectively. Furthermore, 58.8 and 77.8% of HPO phenotypes are also enriched for KEGG and Reactome pathways, respectively. Based on PhenPathDB, PhenPathTOOL analyzes user-defined sets of phenotypes retrieving diseases, genes and functional terms which they share. This information can provide clues for interpreting the co-occurrence of phenotypes in a patient. Conclusions The resource allows finding molecular features useful to investigate diseases characterized by multiple phenotypes, and by this, it can help researchers and physicians in identifying molecular mechanisms and biological functions underlying the concomitant manifestation of phenotypes. The resource is freely available at http://phenpath.biocomp.unibo.it. Electronic supplementary material The online version of this article (10.1186/s12864-019-5868-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Giulia Babbi
- University of Bologna, FABIT, Via San Donato 15, 40126, Bologna, Italy.,Department of BIGEA, University of Bologna, Piazza di Porta S. Donato, 1, 40126, Bologna, Italy
| | - Pier Luigi Martelli
- University of Bologna, FABIT, Via San Donato 15, 40126, Bologna, Italy. .,Interdepartmental Center "Luigi Galvani" for integrated studies of Bioinformatics, Biophysics and Biocomplexity, University of Bologna, CIG, Via G. Petroni 26, 40126, Bologna, Italy.
| | - Rita Casadio
- University of Bologna, FABIT, Via San Donato 15, 40126, Bologna, Italy.,Interdepartmental Center "Luigi Galvani" for integrated studies of Bioinformatics, Biophysics and Biocomplexity, University of Bologna, CIG, Via G. Petroni 26, 40126, Bologna, Italy.,CNR, Institute of Biomembrane and Bioenergetics (IBIOM), Via Giovanni Amendola 165/A, 70126, Bari, Italy
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7
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Vidal S, Brandi N, Pacheco P, Maynou J, Fernandez G, Xiol C, Pascual-Alonso A, Pineda M, Armstrong J, Garcia-Cazorla À, del Carmen Serrano Munuera M, García SC, Troncoso M, Fariña G, García Peñas JJ, Fournier BG, León SR, Guitart M, Baena N, de Nanclares GP, Oci IO, Gutiérrez-Delicado E, Abarrategui B, Barroso E, Santos-Simarro F, Lapunzina P, García FJ, Acedo JM, García A, Martinez MA, Martínez-Bermejo A. The most recurrent monogenic disorders that overlap with the phenotype of Rett syndrome. Eur J Paediatr Neurol 2019; 23:609-620. [PMID: 31105003 DOI: 10.1016/j.ejpn.2019.04.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 02/12/2019] [Accepted: 04/28/2019] [Indexed: 12/30/2022]
Abstract
Rett syndrome (RTT) is an early-onset neurodevelopmental disorder that is caused by mutations in the MECP2 gene; however, defects in other genes (CDKL5 and FOXG1) can lead to presentations that resemble classic RTT, although they are not completely identical. Here, we attempted to identify other monogenic disorders that share features of RTT. A total of 437 patients with a clinical diagnosis of RTT-like were studied; in 242 patients, a custom panel with 17 genes related to an RTT-like phenotype was run via a HaloPlex-Target-Enrichment-System. In the remaining 195 patients, a commercial TruSight-One-Sequencing-Panel was analysed. A total of 40 patients with clinical features of RTT had variants which affect gene function in six genes associated with other monogenic disorders. Twelve patients had variants in STXBP1, nine in TCF4, six in SCN2A, five in KCNQ2, four in MEF2C and four in SYNGAP1. Genetic studies using next generation sequencing (NGS) allowed us to study a larger number of genes associated with RTT-like simultaneously, providing a genetic diagnosis for a wider group of patients. These new findings provide the clinician with more information and clues that could help in the prevention of future symptoms or in pharmacologic therapy.
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Affiliation(s)
- S Vidal
- Sant Joan de Déu Research Foundation, Barcelona, Spain; Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
| | - N Brandi
- School of Medicine, Universitat de Barcelona, Barcelona, Spain
| | - P Pacheco
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - J Maynou
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain; Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
| | - G Fernandez
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain; Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
| | - C Xiol
- Sant Joan de Déu Research Foundation, Barcelona, Spain; Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
| | - A Pascual-Alonso
- Sant Joan de Déu Research Foundation, Barcelona, Spain; Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
| | - M Pineda
- Sant Joan de Déu Research Foundation, Barcelona, Spain
| | | | - J Armstrong
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain; Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain; CIBER-ER (Biomedical Network Research Center for Rare Diseases), Institute of Health Carlos III (ISCIII), Madrid, Spain.
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8
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Persico AM, Ricciardello A, Cucinotta F. The psychopharmacology of autism spectrum disorder and Rett syndrome. HANDBOOK OF CLINICAL NEUROLOGY 2019; 165:391-414. [DOI: 10.1016/b978-0-444-64012-3.00024-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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9
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Abstract
OBJECTIVES Pitt-Hopkins syndrome (PTHS) is a rare genetic disorder caused by insufficient expression of the TCF4 gene. Most cases are characterized by severe intellectual disability, absent speech, motor delays, and autism spectrum disorder. Many have abnormal brain imaging, dysmorphic facial features, and medical comorbidities: myopia, constipation, epilepsy, and apneic spells. The present case study expands existing understanding of this disorder by presenting a unique phenotype with higher cognitive abilities and fewer medical comorbidities. METHODS The present case study reports on a 13-year-old, Caucasian male with a recent diagnosis of PTHS following genetic testing (i.e., whole exome sequencing). He was referred for a neuropsychological evaluation to document his neurocognitive functioning to assist with intervention planning. RESULTS Evaluation of intellectual, attention/executive, memory, visual-motor/fine-motor, academic, adaptive, and emotional/behavioral functioning revealed global impairment across all areas of functioning. However, he demonstrated abilities beyond what has been detailed in the literature, including use of full sentences, capacity to learn and solve novel problems, basic academic functioning, and independent ambulation. CONCLUSIONS Children with PTHS may demonstrate a spectrum of abilities beyond what has been documented in the literature thus far. Failure to recognize this spectrum can result in late identification of an accurate diagnosis. (JINS, 2018, 24, 995-1002).
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10
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Goodspeed K, Newsom C, Morris MA, Powell C, Evans P, Golla S. Pitt-Hopkins Syndrome: A Review of Current Literature, Clinical Approach, and 23-Patient Case Series. J Child Neurol 2018; 33:233-244. [PMID: 29318938 PMCID: PMC5922265 DOI: 10.1177/0883073817750490] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pitt-Hopkins syndrome (PTHS) is a rare, genetic disorder caused by a molecular variant of TCF4 which is involved in embryologic neuronal differentiation. PTHS is characterized by syndromic facies, psychomotor delay, and intellectual disability. Other associated features include early-onset myopia, seizures, constipation, and hyperventilation-apneic spells. Many also meet criteria for autism spectrum disorder. Here the authors present a series of 23 PTHS patients with molecularly confirmed TCF4 variants and describe 3 unique individuals. The first carries a small deletion but does not exhibit the typical facial features nor the typical pattern of developmental delay. The second exhibits typical facial features, but has attained more advanced motor and verbal skills than other reported cases to date. The third displays typical features of PTHS, however inherited a large chromosomal duplication involving TCF4 from his unaffected father with somatic mosaicism. To the authors' knowledge, this is the first chromosomal duplication case reported to date.
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Affiliation(s)
| | - Cassandra Newsom
- University of Texas Southwestern Medical School
- Children’s Health Dallas
| | | | | | - Patricia Evans
- University of Texas Southwestern Medical School
- Children’s Health Dallas
| | - Sailaja Golla
- University of Texas Southwestern Medical School
- Children’s Health Dallas
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11
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Gold WA, Krishnarajy R, Ellaway C, Christodoulou J. Rett Syndrome: A Genetic Update and Clinical Review Focusing on Comorbidities. ACS Chem Neurosci 2018; 9:167-176. [PMID: 29185709 DOI: 10.1021/acschemneuro.7b00346] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Rett syndrome (RTT) is a unique neurodevelopmental disorder that primarily affects females resulting in severe cognitive and physical disabilities. Despite the commendable collective efforts of the research community to better understand the genetics and underlying biology of RTT, there is still no cure. However, in the past 50 years, since the first report of RTT, steady progress has been made in the accumulation of clinical and molecular information resulting in the identification of a number of genes associated with RTT and associated phenotypes, improved diagnostic criteria, natural history studies, curation of a number of databases capturing genotypic and phenotypic data, a number of promising clinical trials and exciting novel therapeutic options which are currently being tested in laboratory and clinical settings. This Review focuses on the current knowledge of the clinical aspects of RTT, with particular attention being paid to clinical trials and the comorbidities of the disorder as well as the genetic etiology and the recognition of new diseases genes.
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Affiliation(s)
- Wendy A Gold
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Rahul Krishnarajy
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - Carolyn Ellaway
- Genetic
Metabolic Disorders Service, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
| | - John Christodoulou
- Genetic
Metabolic Disorders Research Unit, Western Sydney Genetics Program, The Children’s Hospital at Westmead, Sydney, NSW 2145, Australia
- Neurodevelopmental
Genomics Research Group, Murdoch Children’s Research Institute,
and Department of Paediatrics, Melbourne Medical School, University of Melbourne, Melbourne, VIC 3010, Australia
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Vidal S, Brandi N, Pacheco P, Gerotina E, Blasco L, Trotta JR, Derdak S, Del Mar O'Callaghan M, Garcia-Cazorla À, Pineda M, Armstrong J. The utility of Next Generation Sequencing for molecular diagnostics in Rett syndrome. Sci Rep 2017; 7:12288. [PMID: 28947817 PMCID: PMC5613000 DOI: 10.1038/s41598-017-11620-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 08/29/2017] [Indexed: 02/07/2023] Open
Abstract
Rett syndrome (RTT) is an early-onset neurodevelopmental disorder that almost exclusively affects girls and is totally disabling. Three genes have been identified that cause RTT: MECP2, CDKL5 and FOXG1. However, the etiology of some of RTT patients still remains unknown. Recently, next generation sequencing (NGS) has promoted genetic diagnoses because of the quickness and affordability of the method. To evaluate the usefulness of NGS in genetic diagnosis, we present the genetic study of RTT-like patients using different techniques based on this technology. We studied 1577 patients with RTT-like clinical diagnoses and reviewed patients who were previously studied and thought to have RTT genes by Sanger sequencing. Genetically, 477 of 1577 patients with a RTT-like suspicion have been diagnosed. Positive results were found in 30% by Sanger sequencing, 23% with a custom panel, 24% with a commercial panel and 32% with whole exome sequencing. A genetic study using NGS allows the study of a larger number of genes associated with RTT-like symptoms simultaneously, providing genetic study of a wider group of patients as well as significantly reducing the response time and cost of the study.
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Affiliation(s)
- Silvia Vidal
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Núria Brandi
- Facultat de Medicina, Universitat de Barcelona, Barcelona, Spain
| | - Paola Pacheco
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Edgar Gerotina
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Laura Blasco
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Jean-Rémi Trotta
- Centro Nacional de Análisis Genómica (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Sophia Derdak
- Centro Nacional de Análisis Genómica (CNAG-CRG), Center for Genomic Regulation, Barcelona Institute of Science and Technology (BIST), Barcelona, Spain
| | - Maria Del Mar O'Callaghan
- Neurology Service, Hospital Sant Joan de Déu, Barcelona, Spain
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
- CIBER-ER (Biomedical Network Research Center for Rare Diseases), Instituto de Salud Carlos III, Madrid, Spain
| | - Àngels Garcia-Cazorla
- Neurology Service, Hospital Sant Joan de Déu, Barcelona, Spain
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
- CIBER-ER (Biomedical Network Research Center for Rare Diseases), Instituto de Salud Carlos III, Madrid, Spain
| | - Mercè Pineda
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain
| | - Judith Armstrong
- Molecular and Genetics Medicine Section, Hospital Sant Joan de Déu, Barcelona, Spain.
- Institut de Recerca Pediàtrica Hospital Sant Joan de Déu, Barcelona, Spain.
- CIBER-ER (Biomedical Network Research Center for Rare Diseases), Instituto de Salud Carlos III, Madrid, Spain.
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Wang LH, Baker NE. E Proteins and ID Proteins: Helix-Loop-Helix Partners in Development and Disease. Dev Cell 2016; 35:269-80. [PMID: 26555048 DOI: 10.1016/j.devcel.2015.10.019] [Citation(s) in RCA: 110] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/18/2015] [Accepted: 10/23/2015] [Indexed: 01/12/2023]
Abstract
The basic Helix-Loop-Helix (bHLH) proteins represent a well-known class of transcriptional regulators. Many bHLH proteins act as heterodimers with members of a class of ubiquitous partners, the E proteins. A widely expressed class of inhibitory heterodimer partners-the Inhibitor of DNA-binding (ID) proteins-also exists. Genetic and molecular analyses in humans and in knockout mice implicate E proteins and ID proteins in a wide variety of diseases, belying the notion that they are non-specific partner proteins. Here, we explore relationships of E proteins and ID proteins to a variety of disease processes and highlight gaps in knowledge of disease mechanisms.
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Affiliation(s)
- Lan-Hsin Wang
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA
| | - Nicholas E Baker
- Department of Genetics, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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Gold WA, Christodoulou J. The Utility of Next-Generation Sequencing in Gene Discovery for Mutation-Negative Patients with Rett Syndrome. Front Cell Neurosci 2015; 9:266. [PMID: 26236194 PMCID: PMC4500929 DOI: 10.3389/fncel.2015.00266] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2015] [Accepted: 06/29/2015] [Indexed: 01/13/2023] Open
Abstract
Rett syndrome (RTT) is a rare, severe disorder of neuronal plasticity that predominantly affects girls. Girls with RTT usually appear asymptomatic in the first 6–18 months of life, but gradually develop severe motor, cognitive, and behavioral abnormalities that persist for life. A predominance of neuronal and synaptic dysfunction, with altered excitatory–inhibitory neuronal synaptic transmission and synaptic plasticity, are overarching features of RTT in children and in mouse models. Over 90% of patients with classical RTT have mutations in the X-linked methyl-CpG-binding (MECP2) gene, while other genes, including cyclin-dependent kinase-like 5 (CDKL5), Forkhead box protein G1 (FOXG1), myocyte-specific enhancer factor 2C (MEF2C), and transcription factor 4 (TCF4), have been associated with phenotypes overlapping with RTT. However, there remain a proportion of patients who carry a clinical diagnosis of RTT, but who are mutation negative. In recent years, next-generation sequencing technologies have revolutionized approaches to genetic studies, making whole-exome and even whole-genome sequencing possible strategies for the detection of rare and de novo mutations, aiding the discovery of novel disease genes. Here, we review the recent progress that is emerging in identifying pathogenic variations, specifically from exome sequencing in RTT patients, and emphasize the need for the use of this technology to identify known and new disease genes in RTT patients.
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Affiliation(s)
- Wendy Anne Gold
- Western Sydney Genetics Program, New South Wales Centre for Rett Syndrome Research, Children's Hospital at Westmead , Sydney, NSW , Australia ; Discipline of Paediatrics and Child Health, University of Sydney , Sydney, NSW , Australia
| | - John Christodoulou
- Western Sydney Genetics Program, New South Wales Centre for Rett Syndrome Research, Children's Hospital at Westmead , Sydney, NSW , Australia ; Discipline of Paediatrics and Child Health, University of Sydney , Sydney, NSW , Australia ; Discipline of Genetic Medicine, Sydney Medical School, University of Sydney , Sydney, NSW , Australia
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Williamson SL, Ellaway CJ, Peters GB, Pelka GJ, Tam PPL, Christodoulou J. Deletion of protein tyrosine phosphatase, non-receptor type 4 (PTPN4) in twins with a Rett syndrome-like phenotype. Eur J Hum Genet 2014; 23:1171-5. [PMID: 25424712 PMCID: PMC4538211 DOI: 10.1038/ejhg.2014.249] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/13/2014] [Accepted: 09/19/2014] [Indexed: 12/22/2022] Open
Abstract
Rett syndrome (RTT), a neurodevelopmental disorder that predominantly affects females, is primarily caused by variants in MECP2. Variants in other genes such as CDKL5 and FOXG1 are usually associated with individuals who manifest distinct phenotypes that may overlap with RTT. Individuals with phenotypes suggestive of RTT are typically screened for variants in MECP2 and then subsequently the other genes dependent on the specific phenotype. Even with this screening strategy, there are individuals in whom no causative variant can be identified, suggesting that there are other novel genes that contribute to the RTT phenotype. Here we report a de novo deletion of protein tyrosine phosphatase, non-receptor type 4 (PTPN4) in identical twins with a RTT-like phenotype. We also demonstrate the reduced expression of Ptpn4 in a Mecp2 null mouse model of RTT, as well as the activation of the PTPN4 promoter by MeCP2. Our findings suggest that PTPN4 should be considered for addition to the growing list of genes that warrant screening in individuals with a RTT-like phenotype.
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Affiliation(s)
- Sarah L Williamson
- NSW Centre for Rett Syndrome Research, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Carolyn J Ellaway
- 1] NSW Centre for Rett Syndrome Research, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia [2] Disciplines of Paediatrics and Child Health and Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Greg B Peters
- 1] Disciplines of Paediatrics and Child Health and Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia [2] Sydney Genome Diagnostics, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Gregory J Pelka
- Embryology Unit, Children's Medical Research Institute, Sydney, New South Wales, Australia
| | - Patrick P L Tam
- 1] Embryology Unit, Children's Medical Research Institute, Sydney, New South Wales, Australia [2] Discipline of Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - John Christodoulou
- 1] NSW Centre for Rett Syndrome Research, Western Sydney Genetics Program, Children's Hospital at Westmead, Sydney, New South Wales, Australia [2] Disciplines of Paediatrics and Child Health and Genetic Medicine, Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
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Knockdown of human TCF4 affects multiple signaling pathways involved in cell survival, epithelial to mesenchymal transition and neuronal differentiation. PLoS One 2013; 8:e73169. [PMID: 24058414 PMCID: PMC3751932 DOI: 10.1371/journal.pone.0073169] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Accepted: 07/18/2013] [Indexed: 01/04/2023] Open
Abstract
Haploinsufficiency of TCF4 causes Pitt-Hopkins syndrome (PTHS): a severe form of mental retardation with phenotypic similarities to Angelman, Mowat-Wilson and Rett syndromes. Genome-wide association studies have also found that common variants in TCF4 are associated with an increased risk of schizophrenia. Although TCF4 is transcription factor, little is known about TCF4-regulated processes in the brain. In this study we used genome-wide expression profiling to determine the effects of acute TCF4 knockdown on gene expression in SH-SY5Y neuroblastoma cells. We identified 1204 gene expression changes (494 upregulated, 710 downregulated) in TCF4 knockdown cells. Pathway and enrichment analysis on the differentially expressed genes in TCF4-knockdown cells identified an over-representation of genes involved in TGF-β signaling, epithelial to mesenchymal transition (EMT) and apoptosis. Among the most significantly differentially expressed genes were the EMT regulators, SNAI2 and DEC1 and the proneural genes, NEUROG2 and ASCL1. Altered expression of several mental retardation genes such as UBE3A (Angelman Syndrome), ZEB2 (Mowat-Wilson Syndrome) and MEF2C was also found in TCF4-depleted cells. These data suggest that TCF4 regulates a number of convergent signaling pathways involved in cell differentiation and survival in addition to a subset of clinically important mental retardation genes.
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Sweatt JD. Pitt-Hopkins Syndrome: intellectual disability due to loss of TCF4-regulated gene transcription. Exp Mol Med 2013; 45:e21. [PMID: 23640545 PMCID: PMC3674405 DOI: 10.1038/emm.2013.32] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 02/03/2013] [Indexed: 01/22/2023] Open
Abstract
TCF4 (transcription factor 4; E2-2, ITF2) is a transcription factor that when haplo-insufficient causes Pitt-Hopkins Syndrome (PTHS), an autism-spectrum disorder that is associated with pervasive developmental delay and severe intellectual disability. The TCF4 gene is also a risk factor with highly significant linkage to schizophrenia, presumably via overexpression of the TCF4 gene product in the central nervous system. This review will present an overview of the clinical manifestations of PTHS and relate those clinical attributes to the underlying molecular genetics of TCF4. In order to provide a molecular biological context for the loss of function of TCF4 in PTHS, the review will also present a brief overview of the basic biochemistry of TCF4-mediated regulation of cellular and neuronal gene expression. In the final section of this review, I will discuss and speculate upon possible roles for the TCF4 transcription factor in neuronal function and comment upon how understanding these roles may give new insights into the molecular neurobiology of human cognition.
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Affiliation(s)
- J David Sweatt
- Department of Neurobiology and Evelyn F. McKnight Brain Institute, Civitan International Research Center, University of Alabama at Birmingham, Birmingham, AL 35294-2182, USA.
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18
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Dietrich JB. The MEF2 family and the brain: from molecules to memory. Cell Tissue Res 2013; 352:179-90. [DOI: 10.1007/s00441-013-1565-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 01/10/2013] [Indexed: 12/31/2022]
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Bienvenu T, Diebold B, Chelly J, Isidor B. Refining the phenotype associated with MEF2C point mutations. Neurogenetics 2012; 14:71-5. [PMID: 23001426 DOI: 10.1007/s10048-012-0344-7] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2012] [Accepted: 09/11/2012] [Indexed: 01/20/2023]
Abstract
Up to now, only five-point mutations in the MEF2C gene have been described in patients with severe mental retardation with absent speech, limited walking abilities, epilepsy, and lack of gross malformations. In brain, MEF2C is essential for early neurogenesis, neuronal migration, and differentiation. Here, we present a new patient with severe mental retardation, epilepsy, and hand stereotypies associated with a novel MEF2C frameshift mutation c.457delA. The purpose of this work was to clarify criteria for the selection of patients with severe intellectual disability to screen for deficiency in the MEF2C gene. By combining the clinical data of all patients with MEF2C point mutations published so far with the phenotype of our patient, a targeted search for MEF2C mutations could be applied to patients with a severe intellectual deficiency associated with absence of language and hypotonia, strabismus, and epilepsy (started after 6 months, often well controlled by valproate).
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Affiliation(s)
- Thierry Bienvenu
- CNRS UMR 8104, Institut Cochin, Laboratoire de Génétique des Maladies Neurodéveloppementales, Université Paris Descartes, Paris, France.
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Sepp M, Pruunsild P, Timmusk T. Pitt-Hopkins syndrome-associated mutations in TCF4 lead to variable impairment of the transcription factor function ranging from hypomorphic to dominant-negative effects. Hum Mol Genet 2012; 21:2873-88. [PMID: 22460224 DOI: 10.1093/hmg/dds112] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Transcription factor TCF4 (alias ITF2, SEF2 or E2-2) is a broadly expressed basic helix-loop-helix (bHLH) protein that functions as a homo- or heterodimer. Missense, nonsense, frame-shift and splice-site mutations as well as translocations and large deletions encompassing TCF4 gene cause Pitt-Hopkins syndrome (PTHS), a rare developmental disorder characterized by severe motor and mental retardation, typical facial features and breathing anomalies. Irrespective of the mutation, TCF4 haploinsufficiency has been proposed as an underlying mechanism for PTHS. We have recently demonstrated that human TCF4 gene is transcribed using numerous 5' exons. Here, we re-evaluated the impact of all the published PTHS-associated mutations, taking into account the diversity of TCF4 isoforms, and assessed how the reading frame elongating and missense mutations affect TCF4 functions. Our analysis revealed that not all deletions and truncating mutations in TCF4 result in complete loss-of-function and the impact of reading frame elongating and missense mutations ranges from subtle deficiencies to dominant-negative effects. We show that (i) missense mutations in TCF4 bHLH domain and the reading frame elongating mutation damage DNA-binding and transactivation ability in a manner dependent on dimer context (homodimer versus heterodimer with ASCL1 or NEUROD2); (ii) the elongating mutation and the missense mutation at the dimer interface of the HLH domain destabilize the protein; and (iii) missense mutations outside of the bHLH domain cause no major functional deficiencies. We conclude that different PTHS-associated mutations impair the functions of TCF4 by diverse mechanisms and to a varying extent, possibly contributing to the phenotypic variability of PTHS patients.
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Affiliation(s)
- Mari Sepp
- Department of Gene Technology, Tallinn University of Technology, Akadeemia tee 15, Tallinn, Estonia
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