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Scala M, Nishikawa M, Ito H, Tabata H, Khan T, Accogli A, Davids L, Ruiz A, Chiurazzi P, Cericola G, Schulte B, Monaghan KG, Begtrup A, Torella A, Pinelli M, Denommé-Pichon AS, Vitobello A, Racine C, Mancardi MM, Kiss C, Guerin A, Wu W, Gabau Vila E, Mak BC, Martinez-Agosto JA, Gorin MB, Duz B, Bayram Y, Carvalho CMB, Vengoechea JE, Chitayat D, Tan TY, Callewaert B, Kruse B, Bird LM, Faivre L, Zollino M, Biskup S, Striano P, Nigro V, Severino M, Capra V, Costain G, Nagata KI. Variant-specific changes in RAC3 function disrupt corticogenesis in neurodevelopmental phenotypes. Brain 2022; 145:3308-3327. [PMID: 35851598 PMCID: PMC9473360 DOI: 10.1093/brain/awac106] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 02/01/2022] [Accepted: 03/13/2022] [Indexed: 01/17/2023] Open
Abstract
Variants in RAC3, encoding a small GTPase RAC3 which is critical for the regulation of actin cytoskeleton and intracellular signal transduction, are associated with a rare neurodevelopmental disorder with structural brain anomalies and facial dysmorphism. We investigated a cohort of 10 unrelated participants presenting with global psychomotor delay, hypotonia, behavioural disturbances, stereotyped movements, dysmorphic features, seizures and musculoskeletal abnormalities. MRI of brain revealed a complex pattern of variable brain malformations, including callosal abnormalities, white matter thinning, grey matter heterotopia, polymicrogyria/dysgyria, brainstem anomalies and cerebellar dysplasia. These patients harboured eight distinct de novo RAC3 variants, including six novel variants (NM_005052.3): c.34G > C p.G12R, c.179G > A p.G60D, c.186_188delGGA p.E62del, c.187G > A p.D63N, c.191A > G p.Y64C and c.348G > C p.K116N. We then examined the pathophysiological significance of these novel and previously reported pathogenic variants p.P29L, p.P34R, p.A59G, p.Q61L and p.E62K. In vitro analyses revealed that all tested RAC3 variants were biochemically and biologically active to variable extent, and exhibited a spectrum of different affinities to downstream effectors including p21-activated kinase 1. We then focused on the four variants p.Q61L, p.E62del, p.D63N and p.Y64C in the Switch II region, which is essential for the biochemical activity of small GTPases and also a variation hot spot common to other Rho family genes, RAC1 and CDC42. Acute expression of the four variants in embryonic mouse brain using in utero electroporation caused defects in cortical neuron morphology and migration ending up with cluster formation during corticogenesis. Notably, defective migration by p.E62del, p.D63N and p.Y64C were rescued by a dominant negative version of p21-activated kinase 1. Our results indicate that RAC3 variants result in morphological and functional defects in cortical neurons during brain development through variant-specific mechanisms, eventually leading to heterogeneous neurodevelopmental phenotypes.
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Affiliation(s)
| | | | | | - Hidenori Tabata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Developmental Disability Center, 713-8 Kamiya, Kasugai 480-0392, Japan
| | - Tayyaba Khan
- Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Andrea Accogli
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy
| | - Laura Davids
- Department of Human Genetics, Emory Healthcare, Atlanta, GA 30322, USA
| | - Anna Ruiz
- Genetics Laboratory, UDIAT-Centre Diagnòstic, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de, Barcelona, Sabadell, Spain
| | - Pietro Chiurazzi
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica Sacro Cuore, Rome, Italy,Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Gabriella Cericola
- Neuropediatric Department, Helios-Klinikum Hildesheim, Hildesheim, Germany
| | | | | | | | - Annalaura Torella
- Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy,Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Michele Pinelli
- Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy
| | - Anne Sophie Denommé-Pichon
- INSERM UMR1231 Génétique des Anomalies du Développement, Université de Bourgogne Franche-Comté, Dijon, France,Laboratoire de Génétique Moléculaire, UF Innovation en diagnostic génomique des maladies rares, Plateau Technique de Biologie, CHU de Dijon Bourgogne, Dijon, France,Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'interrégion Est, FHU TRANSLAD, Hôpital d'Enfants, CHU de Dijon Bourgogne, Dijon, France
| | - Antonio Vitobello
- INSERM UMR1231 Génétique des Anomalies du Développement, Université de Bourgogne Franche-Comté, Dijon, France,Laboratoire de Génétique Moléculaire, UF Innovation en diagnostic génomique des maladies rares, Plateau Technique de Biologie, CHU de Dijon Bourgogne, Dijon, France
| | - Caroline Racine
- Laboratoire de Génétique Moléculaire, UF Innovation en diagnostic génomique des maladies rares, Plateau Technique de Biologie, CHU de Dijon Bourgogne, Dijon, France,Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'interrégion Est, FHU TRANSLAD, Hôpital d'Enfants, CHU de Dijon Bourgogne, Dijon, France
| | - Maria Margherita Mancardi
- Unit of Child Neuropsychiatry, Department of Medical and Surgical Neuroscience and Rehabilitation, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Courtney Kiss
- Division of Medical Genetics, Department of Pediatrics, Queen’s University, Kingston, ON K7L 2V7, Canada
| | - Andrea Guerin
- Division of Medical Genetics, Department of Pediatrics, Queen’s University, Kingston, ON K7L 2V7, Canada
| | - Wendy Wu
- Genetics and Genome Biology, Research Institute, The Hospital for Sick Children, Toronto, Ontario, Canada,Queen’s University, Kingston, ON, Canada
| | - Elisabeth Gabau Vila
- Paediatric Unit, Parc Taulí Hospital Universitari, Institut d'Investigació i Innovació Parc Taulí I3PT, Universitat Autònoma de, Barcelona, Sabadell, Spain
| | - Bryan C Mak
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA
| | - Julian A Martinez-Agosto
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA,Department of Pediatrics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA,Department of Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA
| | - Michael B Gorin
- Department of Human Genetics, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA,Department of Ophthalmology, Jules Stein Eye Institute, David Geffen School of Medicine, UCLA, Los Angeles 90095, CA, USA,Brain Research Institute, UCLA, Los Angeles 90095, CA, USA
| | - Bugrahan Duz
- Haseki Training and Research Hospital, Istanbul, Turkey
| | - Yavuz Bayram
- Division of Genomic Diagnostics, Department of Pathology and Laboratory Medicine, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Claudia M B Carvalho
- Pacific Northwest Research Institute, Seattle, WA 98122, USA,Baylor College of Medicine, Houston, TX 77030, USA
| | | | - David Chitayat
- The Prenatal Diagnosis and Medical Genetics Program, Department of Obstetrics and Gynecology, Mount Sinai Hospital, University of Toronto, Toronto, Ontario, Canada,Division of Clinical and Metabolic Genetics, Department of Paediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Tiong Yang Tan
- Victorian Clinical Genetics Services, Murdoch Children’s Research Institute, and Department of Paediatrics, University of Melbourne, Melbourne, VIC 3052, Australia
| | - Bert Callewaert
- Center for Medical Genetics, Ghent University Hospital, Gent, Belgium
| | - Bernd Kruse
- Neuropediatric Department, Helios-Klinikum Hildesheim, Hildesheim, Germany
| | - Lynne M Bird
- Department of Pediatrics, University of California San Diego, San Diego, CA, USA,Genetics/Dysmorphology, Rady Children’s Hospital San Diego, San Diego, CA, USA
| | - Laurence Faivre
- INSERM UMR1231 Génétique des Anomalies du Développement, Université de Bourgogne Franche-Comté, Dijon, France,Centre de Génétique et Centre de Référence Anomalies du Développement et Syndromes Malformatifs de l'interrégion Est, FHU TRANSLAD, Hôpital d'Enfants, CHU de Dijon Bourgogne, Dijon, France
| | - Marcella Zollino
- Dipartimento Universitario Scienze della Vita e Sanità Pubblica, Sezione di Medicina Genomica, Università Cattolica Sacro Cuore, Rome, Italy,Genetica Medica, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Saskia Biskup
- Praxis für Humangenetik, Tübingen, Germany,CeGaT GmbH, Tübingen, Germany
| | | | | | - Pasquale Striano
- Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health, University of Genoa, Genoa, Italy,Pediatric Neurology and Muscular Diseases Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy
| | - Vincenzo Nigro
- Telethon Institute of Genetics and Medicine, Pozzuoli, Naples, Italy,Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | | | - Valeria Capra
- Correspondence may also be addressed to: Valeria Capra Medical Genetics Unit, IRCCS Istituto Giannina Gaslini, Genoa, Italy E-mail:
| | - Gregory Costain
- Correspondence may also be addressed to: Gregory Costain Division of Clinical and Metabolic Genetics Department of Pediatrics The Hospital for Sick Children Toronto, Ontario, Canada E-mail:
| | - Koh ichi Nagata
- Correspondence to: Koh-ichi Nagata Department of Molecular Neurobiology Institute for Developmental Research Aichi Human Service Center, 713-8 Kamiya Kasugai, Aichi 480-0392, Japan E-mail:
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