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Dwivedi R, Kaushik M, Tripathi M, Dada R, Tiwari P. Unraveling the genetic basis of epilepsy: Recent advances and implications for diagnosis and treatment. Brain Res 2024; 1843:149120. [PMID: 39032529 DOI: 10.1016/j.brainres.2024.149120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Revised: 07/05/2024] [Accepted: 07/08/2024] [Indexed: 07/23/2024]
Abstract
Epilepsy, affecting approximately 1% of the global population, manifests as recurring seizures and is heavily influenced by genetic factors. Recent advancements in genetic technologies have revolutionized our understanding of epilepsy's genetic landscape. Key studies, such as the discovery of mutations in ion channels (e.g., SCN1A and SCN2A), neurotransmitter receptors (e.g., GABRA1), and synaptic proteins (e.g., SYNGAP1, KCNQ2), have illuminated critical pathways underlying epilepsy susceptibility and pathogenesis. Genome-wide association studies (GWAS) have identified specific genetic variations linked to epilepsy risk, such as variants near SCN1A and PCDH7, enhancing diagnostic accuracy and enabling personalized treatment strategies. Moreover, epigenetic mechanisms, including DNA methylation (e.g., MBD5), histone modifications (e.g., HDACs), and non-coding RNAs (e.g., miR-134), play pivotal roles in altering gene expression and synaptic plasticity, contributing to epileptogenesis. These discoveries offer promising avenues for therapeutic interventions aimed at improving outcomes for epilepsy patients. Genetic testing has become essential in clinical practice, facilitating precise diagnosis and tailored management approaches based on individual genetic profiles. Furthermore, insights into epigenetic regulation suggest novel therapeutic targets for developing more effective epilepsy treatments. In summary, this review highlights significant progress in understanding the genetic and epigenetic foundations of epilepsy. By integrating findings from key studies and specifying genes involved in epigenetic modifications, we underscore the potential for advanced therapeutic strategies in this complex neurological disorder, emphasizing the importance of personalized medicine approaches in epilepsy management.
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Affiliation(s)
- Rekha Dwivedi
- Department of Neurology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Meenakshi Kaushik
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Manjari Tripathi
- Department of Neurology, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Rima Dada
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India
| | - Prabhakar Tiwari
- Department of Anatomy, All India Institute of Medical Sciences (AIIMS), New Delhi 110029, India.
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Farach LS, Richard MA, Wulsin AC, Bebin EM, Krueger DA, Sahin M, Porter BE, McPherson TO, Peters JM, O'Kelley S, Taub KS, Rajaraman R, Randle SC, McClintock WM, Koenig MK, Frost MD, Werner K, Nolan DA, Wong M, Cutter G, Northrup H, Au KS. Drug-Resistant Epilepsy in Tuberous Sclerosis Complex Is Associated With TSC2 Genotype: More Findings From the Preventing Epilepsy Using Vigatrin (PREVeNT) Trial. Pediatr Neurol 2024; 159:62-71. [PMID: 39142021 DOI: 10.1016/j.pediatrneurol.2024.06.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Revised: 05/22/2024] [Accepted: 06/24/2024] [Indexed: 08/16/2024]
Abstract
BACKGROUND Children with tuberous sclerosis complex (TSC) are at high risk for drug-resistant epilepsy (DRE). The ability to stratify those at highest risk for DRE is important for counseling and prompt, aggressive management, necessary to optimize neurocognitive outcomes. Using the extensively phenotyped PREVeNT cohort, we aimed to characterize whether the TSC genotype was associated with DRE. METHODS The study group (N = 70) comprised participants with TSC enrolled at age less than or equal to six months with detailed epilepsy and other phenotypic and genotypic data, prospectively collected as part of the PREVeNT trial. Genotype-phenotype correlations of DRE, time to first abnormal electroencephalography, and time to epilepsy onset were compared using Fisher exact test and regression models. RESULTS Presence of a TSC2 pathogenic variant was significantly associated with DRE, compared with TSC1 and participants with no pathogenic mutation identified. In fact, all participants with DRE had a TSC2 pathogenic variant. Furthermore, TSC2 variants expected to result in no protein product were associated with higher risk for DRE. Finally, TSC1 pathogenic variants were associated with later-onset epilepsy, on average 21.2 months later than those with other genotypes. CONCLUSIONS Using a comprehensively phenotyped cohort followed from infancy, this study is the first to delineate genotype-phenotype correlations for epilepsy severity and onset in children with TSC. Patients with TSC2 pathogenic variants, especially TSC2 pathogenic variants predicted to result in lack of TSC2 protein, are at highest risk for DRE, and are likely to have earlier epilepsy onset than those with TSC1. Clinically, these insights can inform counseling, surveillance, and management.
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Affiliation(s)
- Laura S Farach
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas.
| | - Melissa A Richard
- Division of Hematology-Oncology, Department of Pediatrics, Baylor College of Medicine, Houston, Texas
| | - Aynara C Wulsin
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Elizabeth M Bebin
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Darcy A Krueger
- Division of Neurology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Mustafa Sahin
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, Massachusetts; Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Brenda E Porter
- Department of Neurology, Stanford University, Stanford, California
| | - Tarrant O McPherson
- Department of Biostatistics and Bioinformatics, Emory University, Atlanta, Georgia
| | - Jurriaan M Peters
- Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, Massachusetts; Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Sarah O'Kelley
- Department of Psychology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Katherine S Taub
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Rajsekar Rajaraman
- Department of Pediatrics and Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, Los Angeles, California
| | - Stephanie C Randle
- Division Pediatric Neurology and Epilepsy, Department of Neurology, Seattle Children's Hospital, Seattle, Washington
| | - William M McClintock
- Division of Neurology, Department of Pediatrics, Children's National Medical Center, Washington, District of Columbia
| | - Mary Kay Koenig
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas
| | | | - Klaus Werner
- Department of Pediatrics, Duke University, Durham, North Carolina
| | - Danielle A Nolan
- Beaumont Florence and Richard McBrien Pediatric Neuroscience Center, Beaumont Hospital, Royal Oak, Michigan
| | - Michael Wong
- Department of Neurology, Washington University in Saint Louis, Saint Louis, Missouri
| | - Gary Cutter
- Department of Biostatistics, University of Alabama at Birmingham, Alabama
| | - Hope Northrup
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas
| | - Kit Sing Au
- Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas
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3
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Mekahli D, Müller RU, Marlais M, Wlodkowski T, Haeberle S, de Argumedo ML, Bergmann C, Breysem L, Fladrowski C, Henske EP, Janssens P, Jouret F, Kingswood JC, Lattouf JB, Lilien M, Maleux G, Rozenberg M, Siemer S, Devuyst O, Schaefer F, Kwiatkowski DJ, Rouvière O, Bissler J. Clinical practice recommendations for kidney involvement in tuberous sclerosis complex: a consensus statement by the ERKNet Working Group for Autosomal Dominant Structural Kidney Disorders and the ERA Genes & Kidney Working Group. Nat Rev Nephrol 2024; 20:402-420. [PMID: 38443710 DOI: 10.1038/s41581-024-00818-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2024] [Indexed: 03/07/2024]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the presence of proliferative lesions throughout the body. Management of TSC is challenging because patients have a multifaceted systemic illness with prominent neurological and developmental impact as well as potentially severe kidney, heart and lung phenotypes; however, every organ system can be involved. Adequate care for patients with TSC requires a coordinated effort involving a multidisciplinary team of clinicians and support staff. This clinical practice recommendation was developed by nephrologists, urologists, paediatric radiologists, interventional radiologists, geneticists, pathologists, and patient and family group representatives, with a focus on TSC-associated kidney manifestations. Careful monitoring of kidney function and assessment of kidney structural lesions by imaging enable early interventions that can preserve kidney function through targeted approaches. Here, we summarize the current evidence and present recommendations for the multidisciplinary management of kidney involvement in TSC.
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Affiliation(s)
- Djalila Mekahli
- PKD Research Group, Laboratory of Ion Channel Research, Department of Cellular and Molecular Medicine, KU Leuven, Leuven, Belgium.
- Department of Paediatric Nephrology, University Hospitals Leuven, Leuven, Belgium.
| | - Roman-Ulrich Müller
- Department II of Internal Medicine and Center for Molecular Medicine Cologne, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- CECAD, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Center for Rare Diseases Cologne, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Matko Marlais
- UCL Great Ormond Street Institute of Child Health, University College London, London, UK
| | - Tanja Wlodkowski
- Division of Paediatric Nephrology, Center for Paediatrics and Adolescent Medicine, University Hospital, Heidelberg, Germany
| | - Stefanie Haeberle
- Division of Paediatric Nephrology, Center for Paediatrics and Adolescent Medicine, University Hospital, Heidelberg, Germany
| | - Marta López de Argumedo
- Basque Office for Health Technology Assessment, (OSTEBA), Basque Government, Vitoria-Gasteiz, Spain
| | - Carsten Bergmann
- Department of Medicine IV, Medical Center-University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Medizinische Genetik Mainz, Limbach Genetics, Mainz, Germany
| | - Luc Breysem
- Department of Radiology, University Hospital of Leuven, Leuven, Belgium
| | - Carla Fladrowski
- Associazione Sclerosi Tuberosa ASP, Rome, Italy
- European Tuberous Sclerosis Complex Association (ETSC), Oestrich-Winkel, Germany
| | - Elizabeth P Henske
- Center for LAM Research and Clinical Care, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Peter Janssens
- Department of Nephrology and Arterial Hypertension, Universitair Ziekenhuis Brussel (UZ Brussel), Vrije Universiteit Brussel, Brussels, Belgium
| | - François Jouret
- Division of Nephrology, Department of Internal Medicine, University of Liège Hospital, Liège, Belgium
- Interdisciplinary Group of Applied Genoproteomics, Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - John Christopher Kingswood
- Cardiology Clinical Academic Group, Molecular and Clinical Sciences Research Centre, St Georges University of London, London, UK
| | - Jean-Baptiste Lattouf
- Department of Surgery-Urology, CHUM-Centre Hospitalier de l'Université de Montréal, Montreal, Quebec, Canada
| | - Marc Lilien
- Department of Paediatric Nephrology, Wilhelmina Children´s Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Geert Maleux
- Department of Radiology, University Hospitals Leuven, Leuven, Belgium
| | - Micaela Rozenberg
- European Tuberous Sclerosis Complex Association (ETSC), Oestrich-Winkel, Germany
- Associação de Esclerose Tuberosa em Portugal, Lisbon, Portugal
| | - Stefan Siemer
- Department of Urology and Paediatric Urology, Saarland University, Homburg, Germany
| | - Olivier Devuyst
- Department of Physiology, Mechanisms of Inherited Kidney Disorders, University of Zurich, Zurich, Switzerland
- Institute for Rare Diseases, Saint-Luc Academic Hospital, UC Louvain, Brussels, Belgium
| | - Franz Schaefer
- Division of Paediatric Nephrology, Center for Paediatrics and Adolescent Medicine, University Hospital, Heidelberg, Germany
| | - David J Kwiatkowski
- Cancer Genetics Laboratory, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Olivier Rouvière
- Department of Radiology, Edouard Herriot Hospital, Hospices Civils de Lyon, Lyon, France
- Université Lyon 1, Lyon, France, Faculté de médecine Lyon Est, Lyon, France
| | - John Bissler
- Department of Paediatrics, University of Tennessee Health Science Center and Le Bonheur Children's Hospital, Memphis, TN, USA.
- Children's Foundation Research Institute (CFRI), Le Bonheur Children's Hospital, Memphis, TN, USA.
- Paediatric Medicine Department, St. Jude Children's Research Hospital, Memphis, TN, USA.
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Garcia ABDM, Viola GD, Corrêa BDS, Fischer TDS, Pinho MCDF, Rodrigues GM, Ashton-Prolla P, Rosset C. An overview of actionable and potentially actionable TSC1 and TSC2 germline variants in an online Database. Genet Mol Biol 2024; 46:e20230132. [PMID: 38373162 PMCID: PMC10876083 DOI: 10.1590/1678-4685-gmb-2023-0132] [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: 05/03/2023] [Accepted: 11/26/2023] [Indexed: 02/21/2024] Open
Abstract
Tuberous Sclerosis Complex (TSC) is caused by loss of function germline variants in the TSC1 or TSC2 tumor suppressor genes. Genetic testing for the detection of pathogenic variants in either TSC1 or TSC2 was implemented as a diagnostic criterion for TSC. However, TSC molecular diagnosis can be challenging due to the absence of variant hotspots and the high number of variants described. This review aimed to perform an overview of TSC1/2 variants submitted in the ClinVar database. Variants of uncertain significance (VUS), missense and single nucleotide variants were the most frequent in clinical significance (37-40%), molecular consequence (37%-39%) and variation type (82%-83%) categories in ClinVar in TSC1 and TSC2 variants, respectively. Frameshift and nonsense VUS have potential for pathogenic reclassification if further functional and segregation studies were performed. Indeed, there were few functional assays deposited in the database and literature. In addition, we did not observe hotspots for variation and many variants presented conflicting submissions regarding clinical significance. This study underscored the importance of disseminating molecular diagnostic results in a public database to render the information largely accessible and promote accurate diagnosis. We encourage the performance of functional studies evaluating the pathogenicity of TSC1/2 variants.
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Affiliation(s)
- Arthur Bandeira de Mello Garcia
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Departamento de Genética, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil
| | - Guilherme Danielski Viola
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Departamento de Genética, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil
| | - Bruno da Silveira Corrêa
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Departamento de Genética, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil
| | - Taís da Silveira Fischer
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
| | - Maria Clara de Freitas Pinho
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
- Centro Universitário CESUCA, Cachoeirinha, RS, Brazil
| | - Grazielle Motta Rodrigues
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Ciências Médicas, Porto Alegre, RS, Brazil
| | - Patricia Ashton-Prolla
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Departamento de Genética, Programa de Pós-Graduação em Genética e Biologia Molecular, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Ciências Médicas, Porto Alegre, RS, Brazil
- Hospital de Clínicas de Porto Alegre, Serviço de Genética Médica, Porto Alegre, RS, Brazil
| | - Clévia Rosset
- Hospital de Clínicas de Porto Alegre, Centro de Pesquisa Experimental, Laboratório de Medicina Genômica, Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Programa de Pós-Graduação em Ciências Médicas, Porto Alegre, RS, Brazil
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Farach LS, Northrup H, Nellist M, van Unen L, Hillman P, Klonowska K, Ekong R, Crino PB, Sing Au K. Mild TSC Phenotype and Non-Penetrance Associated with a Frameshift Variant in TSC2 Prompts Caution in Evaluating Pathogenicity of Frameshift Variants. Gene 2023:147566. [PMID: 37311496 DOI: 10.1016/j.gene.2023.147566] [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: 04/04/2023] [Revised: 06/06/2023] [Accepted: 06/09/2023] [Indexed: 06/15/2023]
Abstract
INTRODUCTION Technological advances in genetic testing, particularly the adoption of noninvasive prenatal screening (NIPS) for single gene disorders such as tuberous sclerosis complex (TSC, OMIM# 613254), mean that putative/possible pathogenetic DNA variants can be identified prior to the appearance of a disease phenotype. Without a phenotype, accurate prediction of variant pathogenicity is crucial. Here, we report a TSC2 frameshift variant, NM_000548.5(TSC2):c.4255_4256delCA, predicted to result in nonsense-mediated mRNA decay (NMD) and cessation of TSC2 protein production and thus pathogenic according to ACMG criteria, identified by NIPS and subsequently detected in family members with few or no symptoms of TSC. Due to the lack of TSC-associated features in the family, we hypothesized that the deletion created a non-canonical 5' donor site resulting in cryptic splicing and a transcript encoding active TSC2 protein. Verifying the predicted effect of the variant was key to designating pathogenicity in this case and should be considered for other frameshift variants in other genetic disorders. METHODS Phenotypic information on the family members was collected via review of the medical records and patient reports. RNA studies were performed using proband mRNA isolated from blood lymphocytes for RT-PCR and Sanger sequencing. Functional studies were performed by transient expression of the TSC2 variant proteins in cultured cells, followed by immunoblotting. RESULTS No family members harboring the variant met any major clinical diagnostic criteria for TSC, though a few minor features non-specific to TSC were present. RNA studies supported the hypothesis that the variant caused cryptic splicing, resulting in an mRNA transcript with an in-frame deletion of 93 base pairs r.[4255_4256del, 4251_4343del], p.[(Gln1419Valfs*104), (Gln1419_Ser1449del)]. Expression studies demonstrated that the canonical function of the resulting truncated TSC2 p.Gln1419_Ser1449del protein product was maintained and similar to wildtype. CONCLUSION Although most frameshift variants are likely to result in NMD, the NM_000548.5(TSC2):c.4255_4256delCA variant creates a cryptic 5' splice donor site, resulting in an in-frame deletion that retains TSC2 function, explaining why carriers of the variant do not have typical features of TSC. The information is important for this family and others with the same variant. Equally important is the lesson that predictions can be inaccurate, and that caution should be used when designating frameshift variants as pathogenic, especially when phenotypic information to corroborate testing results is unavailable. Our work demonstrates that functional RNA- and protein-based confirmation of the effects of DNA variants improves molecular genetic diagnostics.
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Affiliation(s)
- Laura S Farach
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA.
| | - Hope Northrup
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Leontine van Unen
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Paul Hillman
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA
| | - Katarzyna Klonowska
- Cancer Genetics Laboratory, Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Rosemary Ekong
- Research Department of Genetics, Evolution and Environment, Darwin Building, University College London, London, United Kingdom
| | - Peter B Crino
- Department of Neurology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Kit Sing Au
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School at the University of Texas Health Science Center at Houston (UTHealth Houston) and Children's Memorial Hermann Hospital, Houston, Texas, USA
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Chan CK, Lim KS, Low SK, Tan CT, Ng CC. Genetic interaction between GABRA1 and ERBB4 variants in the pathogenesis of genetic generalized epilepsy. Epilepsy Res 2023; 189:107070. [PMID: 36584483 DOI: 10.1016/j.eplepsyres.2022.107070] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/06/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
Epilepsy is a complex neurological disease that can be caused by both genetic and environmental factors. Many studies have been conducted to investigate the genetic risk variants and molecular mechanisms of epilepsy. Disruption of excitation-inhibition balance (E/I balance) is one of the widely accepted disease mechanisms of epilepsy. The maintenance of E/I balance is an intricate process that is governed by multiple proteins. Using whole exome sequencing (WES), we identified a novel GABRA1 c.448G>A (p.E150K) variant and ERBB4 c.1972A>T (p.I658F, rs190654033) variant in a Malaysian Chinese family with genetic generalized epilepsy (GGE). The GGE may be triggered by dysregulation of E/I balance mechanism. Segregation of the variants in the family was verified by Sanger sequencing. All family members with GGE inherited both variants. However, family members who carried only one of the variants did not show any symptoms of GGE. Both the GABRA1 and ERBB4 variants were predicted damaging by MutationTaster and CADD, and protein structure analysis showed that the variants had resulted in the formation of additional hydrogen bonds in the mutant proteins. GABRA1 variant could reduce the efficiency of GABAA receptors, and constitutively active ERBB4 receptors caused by the ERBB4 variant promote internalization of GABAA receptors. The interaction between the two variants may cause a greater disruption in E/I balance, which is more likely to induce a seizure. Nevertheless, this disease model was derived from a single small family, further studies are still needed to confirm the verifiability of the purported disease model.
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Affiliation(s)
- Chung-Kin Chan
- Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia; Division of Neurology, Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Kheng-Seang Lim
- Division of Neurology, Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia.
| | - Siew-Kee Low
- Cancer Precision Medicine Center, Japanese Foundation for Cancer Research, Tokyo, Japan
| | - Chong-Tin Tan
- Division of Neurology, Department of Medicine, Faculty of Medicine, Universiti Malaya, Kuala Lumpur, Malaysia
| | - Ching-Ching Ng
- Genetics and Molecular Biology, Institute of Biological Sciences, Faculty of Science, Universiti Malaya, Kuala Lumpur, Malaysia.
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7
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Genotype and Phenotype Landscape of 283 Japanese Patients with Tuberous Sclerosis Complex. Int J Mol Sci 2022; 23:ijms231911175. [PMID: 36232477 PMCID: PMC9569560 DOI: 10.3390/ijms231911175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/16/2022] [Accepted: 09/19/2022] [Indexed: 11/16/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by multiple dysplastic organ lesions and neuropsychiatric symptoms, caused by loss of function mutations in either TSC1 or TSC2. Genotype and phenotype analyses are conducted worldwide, but there have been few large-scale studies on Japanese patients, and there are still many unclear points. This study analyzed 283 Japanese patients with TSC (225 definite, 53 possible, and 5 genetic diagnoses). A total of 200 mutations (64 TSC1, 136 TSC2) were identified, of which 17 were mosaic mutations, 11 were large intragenic deletions, and four were splicing abnormalities due to deep intronic mutations. Several lesions and symptoms differed in prevalence and severity between TSC1 and TSC2 patients and were generally more severe in TSC2 patients. Moreover, TSC2 missense and in-frame mutations may attenuate skin and renal symptoms compared to other TSC2 mutations. Genetic testing revealed that approximately 20% of parents of a proband had mild TSC, which could have been missed. The patient demographics presented in this study revealed a high frequency of TSC1 patients and a low prevalence of epilepsy compared to global statistics. More patients with mild neuropsychiatric phenotypes were diagnosed in Japan, seemingly due to a higher utilization of brain imaging, and suggesting the possibility that a significant amount of mild TSC patients may not be correctly diagnosed worldwide.
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8
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A second hit somatic (p.R905W) and a novel germline intron-mutation of TSC2 gene is found in intestinal lymphangioleiomyomatosis: a case report with literature review. Diagn Pathol 2021; 16:83. [PMID: 34465349 PMCID: PMC8406734 DOI: 10.1186/s13000-021-01138-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 08/11/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by hamartomas in multiple organs associated with germline mutations in TSC1 and TSC2, including exonic, intronic, or mosaic mutations. Gastrointestinal (GI) tract Lymphangioleiomyomatosis (LAM) is an extremely rare manifestation of TSC, with few reported cases. Herein, we aimed to determine the driver mutation, pathogenesis, and relationship of germline and somatic mutations of LAM through whole-genome sequencing (WGS) of the tumor and blood samples and whole transcriptome sequencing (WTS) analysis. CASE PRESENTATION A nine-year-old girl with a full-blown TSC presented with abdominal masses detected during a routine check-up. Resected intestinal masses were diagnosed as LAM by thorough pathological examination. Interestingly, the LAM presented a somatic TSC2 gene mutation in exon 24 (p.R905W, c.C2713T), and the patient had intron retention by a novel germline mutation in the intron region of TSC2 (chr16:2126489, C > G). CONCLUSION Our case suggests that intron retention by a single nucleotide intronic mutation of TSC2 is sufficient to develop severe manifestations of TSC, but the development of LAM requires an additional somatic oncogenic mutation of TSC2.
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9
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Alsowat D, Whitney R, Hewson S, Jain P, Chan V, Kabir N, Amburgey K, Noone D, Lemaire M, McCoy B, Zak M. The Phenotypic Spectrum of Tuberous Sclerosis Complex: A Canadian Cohort. Child Neurol Open 2021; 8:2329048X211012817. [PMID: 34017900 PMCID: PMC8114745 DOI: 10.1177/2329048x211012817] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2020] [Revised: 03/15/2021] [Accepted: 03/30/2021] [Indexed: 11/15/2022] Open
Abstract
Objective We aimed to further elucidate the phenotypic spectrum of Tuberous Sclerosis Complex (TSC) depending on genotype. Methods A retrospective review of patients seen in the TSC clinic at the Hospital for Sick Children was conducted and the frequency of TSC manifestations was compared based on genotype. Results Nineteen-patients had TSC1 mutations, 36 had TSC2 mutations and 11 had no mutation identified (NMI). Patients with TSC2 mutations had a higher frequency of early-onset epilepsy and more frequent systemic manifestations. The NMI group had milder neurologic and systemic manifestations. Our data did not demonstrate that intellectual disability and infantile spasms were more common in TSC2 mutations. Conclusions This is the first Canadian pediatric cohort exploring the genotype-phenotype relationship in TSC. We report that some manifestations are more frequent and severe in TSC2 mutations and that NMI may have a milder phenotype. Disease surveillance and counseling should continue regardless of genotype until this is better elucidated.
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Affiliation(s)
- Daad Alsowat
- Epilepsy Program, Division of Pediatric Neurology, Department of Neuroscience, King Faisal Specialist Hospital and Research Center, Riyadh, Saudi Arabia
| | - Robyn Whitney
- Epilepsy Program, Division of Neurology, Department of Pediatrics, McMaster Children's Hospital, Hamilton, Ontario, Canada
| | - Stacy Hewson
- Department of Genetic Counselling, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Puneet Jain
- Epilepsy Program, Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Valerie Chan
- Epilepsy Program, Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Nadia Kabir
- Epilepsy Program, Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Kimberly Amburgey
- Department of Genetic Counselling, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Damien Noone
- Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Mathieu Lemaire
- Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Blathnaid McCoy
- Epilepsy Program, Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Maria Zak
- Epilepsy Program, Division of Neurology, Department of Pediatrics, The Hospital for Sick Children, Toronto, Ontario, Canada
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10
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Di Napoli C, Gennaro A, Lupica C, Falsaperla R, Leonardi R, Garozzo MT, Polizzi A, Praticò AD, Zanghì A, Ruggieri M. TSC1 and TSC2: Tuberous Sclerosis Complex and Its Related Epilepsy Phenotype. JOURNAL OF PEDIATRIC NEUROLOGY 2021. [DOI: 10.1055/s-0041-1727142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AbstractTuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by a multisystemic involvement. In TSC, reduced function of TSC1 and TSC2 genes products (hamartin and tuberin, respectively) leads to an hyperactivation of the mechanistic target of rapamycin (mTOR) pathway and to a consequent cell growth dysregulation. In TSC patients, neurological and neuropsychiatric manifestations, especially epilepsy and neuropsychiatric comorbidities such as autism or intellectual disability, represent the most disabling features. In particular, epilepsy occurrs up to 80% of patients, is often drug resistant and is frequently associated with neurological impairment. Due to the burden of this morbidity, different treatment strategies have been proposed with the purpose to make patients epilepsy free, such as the use of different antiepileptic drugs like vigabatrin, carbamazepine, valproic acid, and levetiracetam. More recently, a mTOR inhibitor (i.e. everolimus) has showed promising results in terms of seizures reduction.
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Affiliation(s)
- Claudia Di Napoli
- Postgraduate Training Program in Genetics, Department of Biomedical and Biotechnological Sciences, Section of Genetics, University of Catania, Catania, Italy
| | - Alessia Gennaro
- Postgraduate Training Program in Genetics, Department of Biomedical and Biotechnological Sciences, Section of Genetics, University of Catania, Catania, Italy
| | - Carmelania Lupica
- Postgraduate Training Program in Genetics, Department of Biomedical and Biotechnological Sciences, Section of Genetics, University of Catania, Catania, Italy
| | - Raffaele Falsaperla
- Unit of Pediatrics and Pediatric Emergency, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
- Unit of Neonatal Intenstive Care and Neonatology, University Hospital “Policlinico Rodolico-San Marco,” Catania, Italy
| | - Roberta Leonardi
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, Unit of Rare Diseases of the Nervous System in Childhood, University of Catania, Catania, Italy
| | - Maria Teresa Garozzo
- Unit of Pediatrics and Pediatric Emergency, Hospital “Cannizzaro,” Catania, Italy
| | - Agata Polizzi
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
| | - Andrea D. Praticò
- Department of Clinical and Experimental Medicine, Section of Pediatrics and Child Neuropsychiatry, Unit of Rare Diseases of the Nervous System in Childhood, University of Catania, Catania, Italy
| | - Antonio Zanghì
- Department of General Surgery and Medical-Surgical Specialty, University of Catania, Catania, Italy
| | - Martino Ruggieri
- Chair of Pediatrics, Department of Educational Sciences, University of Catania, Catania, Italy
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11
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Farach LS, Richard MA, Lupo PJ, Sahin M, Krueger DA, Wu JY, Bebin EM, Au KS, Northrup H. Epilepsy Risk Prediction Model for Patients With Tuberous Sclerosis Complex. Pediatr Neurol 2020; 113:46-50. [PMID: 33011641 PMCID: PMC10461434 DOI: 10.1016/j.pediatrneurol.2020.07.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/29/2020] [Accepted: 07/25/2020] [Indexed: 01/13/2023]
Abstract
BACKGROUND Individuals with tuberous sclerosis complex are at increased risk of epilepsy. Early seizure control improves developmental outcomes, making identifying at-risk patients critically important. Despite several identified risk factors, it remains difficult to predict. The purpose of the study was to evaluate the combined risk prediction of previously identified risk factors for epilepsy in individuals with tuberous sclerosis complex. METHODS The study group (n = 333) consisted of individuals with tuberous sclerosis complex who were enrolled in the Tuberous Sclerosis Complex Autism Center of Excellence Research Network and UT TSC Biobank. The outcome was defined as having an epilepsy diagnosis. Potential risk factors included sex, TSC genotype, and tuber presence. Logistic regression was used to calculate the odds ratio and P value for the association between each variable and epilepsy. A clinical risk prediction model incorporating all risk factors was built. Area under the curve was calculated to characterize the full model's ability to discriminate individuals with tuberous sclerosis complex with and without epilepsy. RESULTS The strongest risk for epilepsy was presence of tubers (95% confidence interval: 2.39 to 10.89). Individuals with pathogenic TSC2 variants were three times more likely (95% confidence interval: 1.55 to 6.36) to develop seizures compared with those with tuberous sclerosis complex from other causes. The combination of risk factors resulted in an area under the curve 0.73. CONCLUSIONS Simple characteristics of patients with tuberous sclerosis complex can be combined to successfully predict epilepsy risk. A risk assessment model that incorporates sex, TSC genotype, protective TSC2 missense variant, and tuber presence correctly predicts epilepsy in 73% of patients with tuberous sclerosis complex.
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Affiliation(s)
- Laura S Farach
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas.
| | - Melissa A Richard
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Philip J Lupo
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Mustafa Sahin
- Translational Neuroscience Center, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Darcy A Krueger
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio
| | - Joyce Y Wu
- Division of Pediatric Neurology, UCLA Mattel Children's Hospital and David Geffen School of Medicine, Los Angeles, California
| | | | - Kit Sing Au
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Hope Northrup
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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12
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Rosengren T, Nanhoe S, de Almeida LGD, Schönewolf-Greulich B, Larsen LJ, Hey CAB, Dunø M, Ek J, Risom L, Nellist M, Møller LB. Mutational analysis of TSC1 and TSC2 in Danish patients with tuberous sclerosis complex. Sci Rep 2020; 10:9909. [PMID: 32555378 PMCID: PMC7303179 DOI: 10.1038/s41598-020-66588-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 05/19/2020] [Indexed: 02/07/2023] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by hamartomas in the skin and other organs, including brain, heart, lung, kidney and bones. TSC is caused by mutations in TSC1 and TSC2. Here, we present the TSC1 and TSC2 variants identified in 168 Danish individuals out of a cohort of 327 individuals suspected of TSC. A total of 137 predicted pathogenic or likely pathogenic variants were identified: 33 different TSC1 variants in 42 patients, and 104 different TSC2 variants in 126 patients. In 40 cases (24%), the identified predicted pathogenic variant had not been described previously. In total, 33 novel variants in TSC2 and 7 novel variants in TSC1 were identified. To assist in the classification of 11 TSC2 variants, we investigated the effects of these variants in an in vitro functional assay. Based on the functional results, as well as population and genetic data, we classified 8 variants as likely to be pathogenic and 3 as likely to be benign.
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Affiliation(s)
- Thomas Rosengren
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Santoesha Nanhoe
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Luis Gustavo Dufner de Almeida
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Genetics and Evolutionary Biology, Institute of Biosciences, University of Sao Paulo, Sao Paulo, Brazil
| | - Bitten Schönewolf-Greulich
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Lasse Jonsgaard Larsen
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Caroline Amalie Brunbjerg Hey
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Morten Dunø
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Jakob Ek
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Lotte Risom
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Lisbeth Birk Møller
- Clinical Genetics Clinic, Copenhagen University Hospital, Rigshospitalet. Address 1: Kennedy Center, Gl landevej 7, DK-2600, Glostrup, Denmark. Address 2: 4062, Blegdamsvej 9, DK-2100, Østerbro, Denmark.
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13
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Farach LS, Pearson DA, Woodhouse JP, Schraw JM, Sahin M, Krueger DA, Wu JY, Bebin EM, Lupo PJ, Au KS, Northrup H. Tuberous Sclerosis Complex Genotypes and Developmental Phenotype. Pediatr Neurol 2019; 96:58-63. [PMID: 31005478 PMCID: PMC6837240 DOI: 10.1016/j.pediatrneurol.2019.03.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/25/2019] [Accepted: 03/06/2019] [Indexed: 10/27/2022]
Abstract
BACKGROUND Children with tuberous sclerosis complex (TSC), caused by pathogenic variants in TSC1/TSC2, are at risk for intellectual disability. TSC2 pathogenic variants appear to increase the risk, compared with TSC1. However, the effect of TSC2 pathogenic variants on early and specific domains of development hasn't been studied. Using an extensively phenotyped group, we aimed to characterize differences in early intellectual development between genotypes. METHODS The study group (n = 92) included participants with TSC enrolled in a multicenter study involving genetic testing and detailed prospective phenotyping including the Mullen Scales of Early Learning, a validated measure of cognition, language, and motor development in babies and preschool children. Mean T-scores at 24 months for each Mullen Scales of Early Learning domain were calculated for children with, versus without, a TSC2 pathogenic variant. Multivariable linear regression models were used to compare the groups, adjusting for seizures. RESULTS T-scores on every Mullen Scales of Early Learning domain were significantly worse in the TSC2 group. Below average composite scores were present in three-fourths of the TSC2 group, compared with one-fourth of those without TSC2. Having a TSC2 pathogenic variant was associated with lower composite Mullen Scales of Early Learning scores, even when corrected for seizures. CONCLUSIONS In a well-characterized patient population with standardized assessment of multiple aspects of development, we found that having a TSC2 pathogenic variant was associated with significantly lower Mullen Scales of Early Learning scores at age 24 months, independent of seizures. These data suggest that a baby with a TSC2 pathogenic variant is at high risk for significant developmental delays by 24 months.
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Affiliation(s)
- Laura S. Farach
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas,Communications should he addressed to: Laura S. Farach; 6431 Fannin Street MSB 3.142; Houston, TX 77030., (L.S. Farach)
| | - Deborah A. Pearson
- Department of Psychiatry, Division of Child and Adolescent Psychiatry, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - John P. Woodhouse
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Jeremy M. Schraw
- Department of Medicine, Section of Epidemiology and Population Sciences, Baylor College of Medicine, Houston, Texas
| | - Mustafa Sahin
- Translational Neuroscience Center, Department of Neurology, Boston Children’s Hospital, Harvard Medical School, Boston, Massachusetts
| | - Darcy A. Krueger
- Division of Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio
| | - Joyce Y. Wu
- Division of Pediatric Neurology, UCLA Mattel Children’s Hospital and David Geffen School of Medicine, Los Angeles, California
| | | | - Philip J. Lupo
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, Texas
| | - Kit Sing Au
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Hope Northrup
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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14
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Ye Y, Zeng Y. Whole exome sequencing identifies a novel intron heterozygous mutation in TSC2 responsible for tuberous sclerosis complex. Sci Rep 2019; 9:4456. [PMID: 30872599 PMCID: PMC6418313 DOI: 10.1038/s41598-019-38898-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/21/2018] [Indexed: 11/09/2022] Open
Abstract
This study was aimed to identify the potentially pathogenic gene variants that contribute to the etiology of the tuberous sclerosis complex. A Chinese pedigree with tuberous sclerosis complex was collected and the exomes of two affected individuals were sequenced using the whole exome sequencing technology. The resulting variants from whole exome sequencing were filtered by basic and advanced biological information analysis and the candidate mutation was verified as heterozygous by sanger sequencing. After basic and advanced biological information analysis, a total of 9 single nucleotide variants were identified, which were all follow the dominant inheritance pattern. Among which, the intron heterozygous mutation c.600-145 C > T transition in TSC2 was identified and validated in the two affected individuals. In silico analysis with human splicing finder (HSF) predicted the effect of the c.600-145 C > T mutations on TSC2 mRNA splicing, and detected the creation of a new exonic cryptic donor site, which would result in a frame-shift, and finally premature termination codon. Our results reported the novel intron heterozygous mutation c.600-145 C > T in TSC2 may contribute to TSC, expanding our understanding of the causally relevant genes for this disorder.
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Affiliation(s)
- Yicong Ye
- Department of Cardiology, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China
- Department of Cardiology, Chinese Academy of Medical College and Peking Union Medical College Hospital; Peking Union Medical College Hospital, Beijing, 100730, China
| | - Yong Zeng
- Department of Cardiology, Beijing Institute of Heart, Lung and Blood Vessel Diseases, Beijing Anzhen Hospital, Capital Medical University, Beijing, 100029, China.
- Department of Cardiology, Chinese Academy of Medical College and Peking Union Medical College Hospital; Peking Union Medical College Hospital, Beijing, 100730, China.
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15
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Pippucci T, Licchetta L, Baldassari S, Marconi C, De Luise M, Myers C, Nardi E, Provini F, Cameli C, Minardi R, Bacchelli E, Giordano L, Crichiutti G, d'Orsi G, Seri M, Gasparre G, Mefford HC, Tinuper P, Bisulli F. Contribution of ultrarare variants in mTOR pathway genes to sporadic focal epilepsies. Ann Clin Transl Neurol 2019; 6:475-485. [PMID: 30911571 PMCID: PMC6414475 DOI: 10.1002/acn3.722] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 12/07/2018] [Accepted: 12/08/2018] [Indexed: 01/16/2023] Open
Abstract
Objective We investigated the contribution to sporadic focal epilepsies (FE) of ultrarare variants in genes coding for the components of complexes regulating mechanistic Target Of Rapamycin (mTOR)complex 1 (mTORC1). Methods We collected genetic data of 121 Italian isolated FE cases and 512 controls by Whole Exome Sequencing (WES) and single-molecule Molecular Inversion Probes (smMIPs) targeting 10 genes of the GATOR1, GATOR2, and TSC complexes. We collapsed "qualifying" variants (ultrarare and predicted to be deleterious or loss of function) across the examined genes and sought to identify their enrichment in cases compared to controls. Results We found eight qualifying variants in cases and nine in controls, demonstrating enrichment in FE patients (P = 0.006; exact unconditional test, one-tailed). Pathogenic variants were identified in DEPDC5 and TSC2, both major genes for Mendelian FE syndromes. Interpretation Our findings support the contribution of ultrarare variants in genes in the mTOR pathway complexes GATOR and TSC to the risk of sporadic FE and a shared genetic basis between rare and common epilepsies. The identification of a monogenic etiology in isolated cases, most typically encountered in clinical practice, may offer to a broader community of patients the perspective of precision therapies directed by the underlying genetic cause.
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Affiliation(s)
- Tommaso Pippucci
- Medical Genetics UnitPolyclinic Sant'Orsola‐Malpighi University HospitalBolognaItaly
| | - Laura Licchetta
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
- Department of Biomedical and Neuromotor Sciences (DIBINEM)University of BolognaBolognaItaly
| | - Sara Baldassari
- Department of Biomedical and Surgical Sciences (DIMEC)University of BolognaBolognaItaly
| | - Caterina Marconi
- Department of Biomedical and Surgical Sciences (DIMEC)University of BolognaBolognaItaly
| | - Monica De Luise
- Department of Biomedical and Surgical Sciences (DIMEC)University of BolognaBolognaItaly
| | - Candace Myers
- Division of Genetic MedicineDepartment of PediatricsUniversity of WashingtonSeattleWashington
| | - Elena Nardi
- Department of Statistical Sciences “Paolo Fortunati”University of BolognaBolognaItaly
| | - Federica Provini
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
- Department of Biomedical and Neuromotor Sciences (DIBINEM)University of BolognaBolognaItaly
| | - Cinzia Cameli
- Department of Pharmacy and BiotechnologyUniversity of BolognaBolognaItaly
| | - Raffaella Minardi
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
- Department of Biomedical and Neuromotor Sciences (DIBINEM)University of BolognaBolognaItaly
| | - Elena Bacchelli
- Department of Pharmacy and BiotechnologyUniversity of BolognaBolognaItaly
| | | | | | - Giuseppe d'Orsi
- Epilepsy CenterClinic of Nervous System DiseasesUniversity of FoggiaRiuniti HospitalFoggiaItaly
| | - Marco Seri
- Medical Genetics UnitPolyclinic Sant'Orsola‐Malpighi University HospitalBolognaItaly
- Department of Biomedical and Surgical Sciences (DIMEC)University of BolognaBolognaItaly
| | - Giuseppe Gasparre
- Department of Biomedical and Surgical Sciences (DIMEC)University of BolognaBolognaItaly
| | - Heather C. Mefford
- Division of Genetic MedicineDepartment of PediatricsUniversity of WashingtonSeattleWashington
| | - Paolo Tinuper
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
- Department of Biomedical and Neuromotor Sciences (DIBINEM)University of BolognaBolognaItaly
| | - Francesca Bisulli
- IRCCS Istituto delle Scienze Neurologiche di BolognaBolognaItaly
- Department of Biomedical and Neuromotor Sciences (DIBINEM)University of BolognaBolognaItaly
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16
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Peron A, Au KS, Northrup H. Genetics, genomics, and genotype-phenotype correlations of TSC: Insights for clinical practice. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2018; 178:281-290. [PMID: 30255984 DOI: 10.1002/ajmg.c.31651] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 08/22/2018] [Indexed: 01/28/2023]
Abstract
Tuberous Sclerosis Complex (TSC) is a multisystem autosomal dominant condition caused by inactivating pathogenic variants in either the TSC1 or the TSC2 gene, leading to hyperactivation of the mTOR pathway. Here, we present an update on the genetic and genomic aspects of TSC, with a focus on clinical and laboratory practice. We briefly summarize the structure of TSC1 and TSC2 as well as their protein products, and discuss current diagnostic testing, addressing mosaicism. We consider genotype-phenotype correlations as an example of precision medicine, and discuss genetic counseling in TSC, with the aim of providing geneticists and health care practitioners involved in the care of TSC individuals with useful tools for their practice.
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Affiliation(s)
- Angela Peron
- Child Neuropsychiatry Unit-Epilepsy Center (Service of Medical Genetics), San Paolo Hospital, Department of Health Sciences, Università degli Studi di Milano, Milan, Italy.,Department of Pediatrics, Division of Medical Genetics, University of Utah School of Medicine, Salt Lake City, Utah
| | - Kit Sing Au
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Hope Northrup
- Department of Pediatrics, Division of Medical Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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17
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Bah I, Fahiminiya S, Bégin LR, Hamel N, D'Agostino MD, Tanguay S, Foulkes WD. Atypical tuberous sclerosis complex presenting as familial renal cell carcinoma with leiomyomatous stroma. JOURNAL OF PATHOLOGY CLINICAL RESEARCH 2018; 4:167-174. [PMID: 29659200 PMCID: PMC6065116 DOI: 10.1002/cjp2.104] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Revised: 04/04/2018] [Accepted: 04/09/2018] [Indexed: 12/17/2022]
Abstract
We report an atypical tuberous sclerosis complex (TSC) phenotype presenting as familial multiple renal cell carcinomas (RCCs) with (angio)leiomyomatous stroma (RCCLS) (5/7 familial RCCs) on a background of multiple angiomyolipomas, hypopigmented skin macules, and absence of neurological anomalies. In the index case and three relatives, germline genetic testing identified a heterozygous TSC2 missense pathogenic variant [c.2714 G > A, (p.Arg905Gln)], a rare TSC‐associated alteration which has previously been associated with a milder TSC phenotype. Whole‐exome sequencing of five RCCs from the index case and one RCC from his mother demonstrated either unique tumour‐specific deleterious second hits in TSC2 or significant allelic imbalance at the TSC2 gene locus (5/6 RCCs). This study confirms the key tumourigenic role of tumour‐specific TSC2 second hits in TSC‐associated RCCs and supports the notion that RCCLS may be strongly related to abnormalities of the mTOR pathway.
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Affiliation(s)
- Ismaël Bah
- Department of Pathology, McGill University Health Centre, Montreal, QC, Canada
| | - Somayyeh Fahiminiya
- Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Génome Québec Innovation Centre, McGill University, Montreal, QC, Canada
| | - Louis R Bégin
- Division of Anatomic Pathology, Hôpital du Sacré-Coeur de Montréal, Montreal, QC, Canada
| | - Nancy Hamel
- Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada
| | - Maria D D'Agostino
- Department of Human Genetics, McGill University, Montreal, QC, Canada.,Department of Medical Genetics, McGill University Health Center, Montreal, QC, Canada
| | - Simon Tanguay
- Division of Urology, McGill University Health Center, Montreal, QC, Canada
| | - William D Foulkes
- Cancer Research Program, Research Institute of the McGill University Health Centre, Montreal, QC, Canada.,Department of Human Genetics, McGill University, Montreal, QC, Canada.,Department of Medical Genetics, Lady Davis Institute, Segal Cancer Centre, Jewish General Hospital, Montreal, QC, Canada.,Program in Cancer Genetics, Department of Oncology and Human Genetics, McGill University, Montreal, QC, Canada
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18
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Wang F, Xiong S, Wu L, Chopra M, Hu X, Wu B. A novel TSC2 missense variant associated with a variable phenotype of tuberous sclerosis complex: case report of a Chinese family. BMC MEDICAL GENETICS 2018; 19:90. [PMID: 29843636 PMCID: PMC5975528 DOI: 10.1186/s12881-018-0611-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Accepted: 05/18/2018] [Indexed: 11/10/2022]
Abstract
Background Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder characterized by the development of hamartomas in multiple organs, including the brain, heart, skin, kidney, lung and retina. A diagnosis of TSC is established with a recently revised clinical/radiological set of criteria and/or a causative mutation in TSC1 or TSC2 gene. Case presentation We report a Chinese TSC family with two siblings presenting with multiple hypomelanotic macules, cardiac rhabdomyomas and cortical tubers associated with a small subependymal nodule. The older child had seizures. A novel heterozygous missense variant in the TSC2 gene (c.899G > T, p.G300 V) was identified and shown to be inherited from their father as well as paternal grandfather, both of whom presented with variable TSC-associated signs and symptoms. Conclusion We identified a novel heterozygous TSC2 variant c.899G > T as the causative mutation in a Chinese family with TSC, resulting in wide intrafamilial phenotypic variability. Our study illustrates the importance of clinical evaluation and genetic testing for family members of the patient affected with TSC.
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Affiliation(s)
- Feng Wang
- Department of Cardiology, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, People's Republic of China
| | - Shiyi Xiong
- Fetal Medicine Unit & Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China
| | - Lin Wu
- Department of Cardiology, Children's Hospital of Fudan University, 399 Wanyuan Road, Shanghai, 201102, People's Republic of China.
| | - Maya Chopra
- Fetal Medicine Unit & Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, People's Republic of China.,Department of Medical Genomics, Royal Prince Alfred Hospital, Missenden Road, Sydney, NSW, Australia
| | - Xihong Hu
- Department of Radiology, Children's Hospital of Fudan University, Shanghai, People's Republic of China
| | - Bingbing Wu
- Institute of Pediatrics, Children's Hospital of Fudan University, Shanghai, People's Republic of China
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19
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Pattern of TSC1 and TSC2 germline mutations in Russian patients with tuberous sclerosis. J Hum Genet 2018; 63:597-604. [PMID: 29476190 DOI: 10.1038/s10038-018-0416-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/07/2017] [Accepted: 01/19/2018] [Indexed: 12/17/2022]
Abstract
Tuberous sclerosis (TS) is a rare autosomal-dominant genetic disease. TS is manifested by the development of multiple hamartomas, which affect brain, kidneys, retina, skin and other organs. This study aimed to reveal specific features of molecular epidemiology of TS in Russia. Blood DNA samples from 61 patients with definite (n = 53) or probable (n = 8) clinical diagnosis of TS were tested for mutations in TSC1 and TSC2 genes using Sanger sequencing and MLPA analysis. Five TSC1/2 mutation-negative patients were further analyzed by exome sequencing. TSC1/2 mutations were detected in 53/61 patients (87%): 39 (74%) carried mutations in the TSC2 and 14 (26%) in the TSC1. Large rearrangements (exon deletions/duplications) affected exclusively TSC2, accounting for 15% of lesions of this gene. 6/8 (75%) patients with incomplete clinical manifestation of TS carried TSC1/2 gene lesion. Overall, 96% of detected germline TSC1/2 mutations occurred de novo. Patients with no mutation identified (NMI) differed from TSC1/2 mutation carriers, being lacking cortical tubers and subependymal nodules but having higher frequencies of renal angiomyolipomas, rhabdomyomas, and lymphangioleiomyomatosis. Exome sequencing failed to identify overt disease-causing mutation candidates among NMI patients. Russian patients with TS have increased frequency of TSC2 large gene rearrangements and TSC1/2 mutations occurring de novo as compared to other studies. Patients with suspected TS diagnosis but NMI status may represent a distinct disease entity.
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20
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Farach LS, Gibson WT, Sparagana SP, Nellist M, Stumpel CTRM, Hietala M, Friedman E, Pearson DA, Creighton SP, Wagemans A, Segel R, Ben-Shalom E, Au KS, Northrup H. TSC2 c.1864C>T variant associated with mild cases of tuberous sclerosis complex. Am J Med Genet A 2017; 173:771-775. [PMID: 28211972 DOI: 10.1002/ajmg.a.38083] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 11/21/2016] [Indexed: 11/08/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominantly inherited disorder with variable expressivity associated with hamartomatous tumors, abnormalities of the skin, and neurologic problems including seizures, intellectual disability, and autism. TSC is caused by pathogenic variants in either TSC1 or TSC2. In general, TSC2 pathogenic variants are associated with a more severe phenotype than TSC1 pathogenic variants. Here, we report a pathogenic TSC2 variant, c.1864C>T, p.(Arg622Trp), associated with a mild phenotype, with most carriers meeting fewer than two major clinical diagnostic criteria for TSC. This finding has significant implications for counseling patients regarding prognosis. More patient data are required before changing the surveillance recommendations for patients with the reported variant. However, consideration should be given to tailoring surveillance recommendations for all pathogenic TSC1 and TSC2 variants with documented milder clinical sequelae. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Laura S Farach
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - William T Gibson
- Department of Medical Genetics, BC Children's Hospital and UBC, Vancouver, British Columbia, Canada
| | - Steven P Sparagana
- Division of Neurology, Texas Scottish Rite Hospital for Children and University of Texas Southwestern Medical School, Dallas, Texas
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Connie T R M Stumpel
- Department of Clinical Genetics and School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center (MUMC), Maastricht, The Netherlands
| | - Marja Hietala
- Department of Clinical Genetics and Department of Medical Biochemistry and Genetics, University of Turku and Turku University Hospital, Turku, Finland
| | - Elliott Friedman
- Department of Diagnostic and Interventional Imaging, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Deborah A Pearson
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Susan P Creighton
- Department of Medical Genetics, BC Women's Hospital and UBC, Vancouver, British Columbia, Canada
| | - Annemiek Wagemans
- Department of Clinical Genetics and School for Oncology and Developmental Biology (GROW), Maastricht University Medical Center (MUMC), Maastricht, The Netherlands.,Koraalgroep, Maasveld, Maastricht, The Netherlands
| | - Reveel Segel
- Medical Genetics Institute, Shaare Zedek Medical Center and the Hebrew University School of Medicine, Jerusalem, Israel
| | - Efrat Ben-Shalom
- Department of Pediatric Nephrology, Shaare Zedek Medical Center, Jerusalem, Israel
| | - Kit Sing Au
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
| | - Hope Northrup
- Division of Medical Genetics, Department of Pediatrics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas
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21
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Abstract
Tuberous sclerosis(TS) is an autosomal dominant disease caused by mutations in TSC1 and TSC2 genes. TSC2 gene is located in chromosome 16p13.3, adjacent to PKD1 gene, responsible for the autosomal dominant polycystic kidney disease. In a rare subgroup of patients, the presence of a deletion which simultaneously affects the TSC2 and PKD1 genes has been confirmed. TSC2/PKD1-Contiguous Gene Syndrome is characterised by the early appearance of autosomal dominant polycystic kidney disease in combination with several phenotypic manifestations of TS. We present a 13-year-old girl with bilateral renal cysts detected at the age of 9 months. At the age of 13, she was referred to the Dermatology Outpatients Clinic due to a facial cutaneous eruption. She presented with facial erythema, fibroadenomas with malar distribution and disseminated hypomelanotic macules, meeting the criteria for TS. TSC2/PKD1 Contiguous Gene Syndrome deletion was suspected, being later confirmed by genetic testing.
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Affiliation(s)
| | - Telma Francisco
- Department of Pediatrics, Hospital Dona Estefânia, CHLC, Lisboa, Portugal
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22
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Rosset C, Vairo F, Bandeira IC, Correia RL, de Goes FV, da Silva RTB, Bueno LSM, de Miranda Gomes MCS, Galvão HDCR, Neri JICF, Achatz MI, Netto CBO, Ashton-Prolla P. Molecular analysis of TSC1 and TSC2 genes and phenotypic correlations in Brazilian families with tuberous sclerosis. PLoS One 2017; 12:e0185713. [PMID: 28968464 PMCID: PMC5624610 DOI: 10.1371/journal.pone.0185713] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 09/18/2017] [Indexed: 12/22/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant multisystem disorder characterized by the development of multiple hamartomas in many organs and tissues. It occurs due to inactivating mutations in either of the two genes, TSC1 and TSC2, following a second hit in a tumor suppressor gene in most hamartomas. Comprehensive screening for mutations in both the TSC1 and TSC2 loci has been performed in several cohorts of patients and a broad spectrum of pathogenic mutations have been described. In Brazil, there is no data regarding incidence and prevalence of tuberous sclerosis and mutations in TSC1 and TSC2. We analyzed both genes in 53 patients with high suspicion of tuberous sclerosis using multiplex-ligation dependent probe amplification and a customized next generation sequencing panel. Confirmation of all variants was done by the Sanger method. We identified 50 distinct variants in 47 (89%) of the patients. Five were large rearrangements and 45 were point mutations. The symptoms presented by our series of patients were not different between male and female individuals, except for the more common occurrence of shagreen patch in women (p = 0.028). In our series, consistent with other studies, TSC2 mutations were associated with a more severe phenotypic spectrum than TSC1 mutations. This is the first study that sought to characterize the molecular spectrum of Brazilian individuals with tuberous sclerosis.
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Affiliation(s)
- Clévia Rosset
- Laboratório de Medicina Genômica – Centro de Pesquisa Experimental – Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
- Programa de pós-graduação em genética e biologia molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Filippo Vairo
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Isabel Cristina Bandeira
- Laboratório de Medicina Genômica – Centro de Pesquisa Experimental – Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Rudinei Luis Correia
- Laboratório de Medicina Genômica – Centro de Pesquisa Experimental – Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
| | - Fernanda Veiga de Goes
- Instituto Fernandes Figueira, Fundação Osvaldo Cruz, Rio de Janeiro, Rio de Janeiro, Brazil
| | | | | | | | | | - João I. C. F. Neri
- Centro Especializado em Reabilitação e Habilitação, Natal, Rio Grande do Norte, Brazil
| | - Maria Isabel Achatz
- A.C. Camargo Cancer Center, São Paulo, São Paulo, Brazil
- Clinical Genetics Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Rockville, United States of America
| | | | - Patricia Ashton-Prolla
- Laboratório de Medicina Genômica – Centro de Pesquisa Experimental – Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
- Programa de pós-graduação em genética e biologia molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil
- Departamento de Genética - Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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23
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Mortaji P, Morris KT, Samedi V, Eberhardt S, Ryan S. Pancreatic neuroendocrine tumor in a patient with a TSC1 variant: case report and review of the literature. Fam Cancer 2017; 17:275-280. [DOI: 10.1007/s10689-017-0029-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Rosset C, Netto CBO, Ashton-Prolla P. TSC1 and TSC2 gene mutations and their implications for treatment in Tuberous Sclerosis Complex: a review. Genet Mol Biol 2017; 40:69-79. [PMID: 28222202 PMCID: PMC5409767 DOI: 10.1590/1678-4685-gmb-2015-0321] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/01/2016] [Indexed: 01/08/2023] Open
Abstract
Tuberous sclerosis complex is an autosomal dominant disorder characterized by skin
manifestations and formation of multiple tumors in different organs, mainly in the
central nervous system. Tuberous sclerosis is caused by the mutation of one of two
tumor suppressor genes, TSC1 or TSC2. Currently,
the development of novel techniques and great advances in high-throughput genetic
analysis made mutation screening of the TSC1 and
TSC2 genes more widely available. Extensive studies of the
TSC1 and TSC2 genes in patients with TSC
worldwide have revealed a wide spectrum of mutations. Consequently, the discovery of
the underlying genetic defects in TSC has furthered our
understanding of this complex genetic disorder, and genotype-phenotype correlations
are becoming possible, although there are still only a few clearly established
correlations. This review focuses on the main symptoms and genetic alterations
described in TSC patients from 13 countries in three continents, as well as on
genotype-phenotype correlations established to date. The determination of
genotype-phenotype correlations may contribute to the establishment of successful
personalized treatment for TSC.
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Affiliation(s)
- Clévia Rosset
- Laboratório de Medicina Genômica, Centro de Pesquisa Experimental. Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | | | - Patricia Ashton-Prolla
- Laboratório de Medicina Genômica, Centro de Pesquisa Experimental. Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil.,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre (HCPA), Porto Alegre, RS, Brazil.,Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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25
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Fox J, Ben-Shachar S, Uliel S, Svirsky R, Saitsu H, Matsumoto N, Fattal-Valevski A. Rare familial TSC2 gene mutation associated with atypical phenotype presentation of Tuberous Sclerosis Complex. Am J Med Genet A 2017; 173:744-748. [PMID: 28127866 DOI: 10.1002/ajmg.a.38027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/07/2016] [Indexed: 12/24/2022]
Abstract
Tuberous sclerosis complex (TSC) is a neurocutaneous disorder that results from mutations within either the TSC1 gene or the TSC2 gene. Diagnosis is based on well-established clinical criteria or genetic criteria. We describe an 18-month-old boy who presented with seizures and a single hypopigmented macule. He did not meet consensus criteria for the clinical diagnosis of TSC. Exome sequencing revealed a heterozygous TSC2 mutation (c.5138G>A (p.Arg1713His)) in the patient. This heterozygous alteration was detected in his mother as well as several other maternal family members. The mother and other family members with the mutation were asymptomatic except for the presence of hypopigmented macules. The phenotypic characteristics of the individuals in this family were not suggestive of a TSC2 mutation as none satisfied the clinical criteria for even a diagnosis of possible TSC. This case provides evidence for a unique TSC2 mutation that resulted in an atypical clinical presentation and indicates potential shortcomings of the current diagnostic criteria for TSC. These findings may have implications for genetic counseling and screening. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jonah Fox
- New York State/American Program, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shay Ben-Shachar
- Genetic Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shimrit Uliel
- Pediatric Neurology Unit, Tel Aviv Sourasky Medical Center, Dana-Dwek Children's Hospital, Tel Aviv, Israel
| | - Ran Svirsky
- Genetic Institute, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.,Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hirotomo Saitsu
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Naomichi Matsumoto
- Department of Human Genetics, Yokohama City University Graduate School of Medicine, Yokohama, Japan
| | - Aviva Fattal-Valevski
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Pediatric Neurology Unit, Tel Aviv Sourasky Medical Center, Dana-Dwek Children's Hospital, Tel Aviv, Israel
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26
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Wang J, Lin ZJ, Liu L, Xu HQ, Shi YW, Yi YH, He N, Liao WP. Epilepsy-associated genes. Seizure 2016; 44:11-20. [PMID: 28007376 DOI: 10.1016/j.seizure.2016.11.030] [Citation(s) in RCA: 275] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/03/2016] [Accepted: 11/30/2016] [Indexed: 10/20/2022] Open
Abstract
Development in genetic technology has led to the identification of an increasing number of genes associated with epilepsy. These discoveries will both provide the basis for including genetic tests in clinical practice and improve diagnosis and treatment of epilepsy. By searching through several databases (OMIM, HGMD, and EpilepsyGene) and recent publications on PubMed, we found 977 genes that are associated with epilepsy. We classified these genes into 4 categories according to the manifestation of epilepsy in phenotypes. We found 84 genes that are considered as epilepsy genes: genes that cause epilepsies or syndromes with epilepsy as the core symptom. 73 genes were listed as neurodevelopment-associated genes: genes associated with both brain-development malformations and epilepsy. Several genes (536) were epilepsy-related: genes associated with both physical or other systemic abnormalities and epilepsy or seizures. We found 284 additional genes putatively associated with epilepsy; this requires further verification. These integrated data will provide new insights useful for both including genetic tests in the clinical practice and evaluating the results of genetic tests. We also summarized the epilepsy-associated genes according to their function, with the goal to better characterize the association between genes and epilepsies and to further understand the mechanisms underlying epilepsy.
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Affiliation(s)
- Jie Wang
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Zhi-Jian Lin
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Liu Liu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Hai-Qing Xu
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China; Department of Neurology, Affiliated Zhongda Hospital, School of Medicine, Southeast University, Nanjing, China
| | - Yi-Wu Shi
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Yong-Hong Yi
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
| | - Na He
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China.
| | - Wei-Ping Liao
- Institute of Neuroscience and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou 510260, China; Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China.
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Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder that affects multiple organ systems and is caused by loss-of-function mutations in one of two genes: TSC1 or TSC2. The disorder can affect both adults and children. First described in depth by Bourneville in 1880, it is now estimated that nearly 2 million people are affected by the disease worldwide. The clinical features of TSC are distinctive and can vary widely between individuals, even within one family. Major features of the disease include tumours of the brain, skin, heart, lungs and kidneys, seizures and TSC-associated neuropsychiatric disorders, which can include autism spectrum disorder and cognitive disability. TSC1 (also known as hamartin) and TSC2 (also known as tuberin) form the TSC protein complex that acts as an inhibitor of the mechanistic target of rapamycin (mTOR) signalling pathway, which in turn plays a pivotal part in regulating cell growth, proliferation, autophagy and protein and lipid synthesis. Remarkable progress in basic and translational research, in addition to several randomized controlled trials worldwide, has led to regulatory approval of the use of mTOR inhibitors for the treatment of renal angiomyolipomas, brain subependymal giant cell astrocytomas and pulmonary lymphangioleiomyomatosis, but further research is needed to establish full indications of therapeutic treatment. In this Primer, we review the state-of-the-art knowledge in the TSC field, including the molecular and cellular basis of the disease, medical management, major knowledge gaps and ongoing research towards a cure.
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Affiliation(s)
- Elizabeth P Henske
- Pulmonary and Critical Care Medicine Division, Brigham and Women's Hospital, Harvard Medical School, 15 Francis Street, Boston, Massachusetts 02115, USA
| | - Sergiusz Jóźwiak
- Department of Pediatric Neurology, Medical University of Warsaw, Warsaw, Poland.,Children's Memorial Health Institute, Warsaw, Poland
| | | | - Julian R Sampson
- Institute of Medical Genetics, Division of Cancer and Genetics, Cardiff University School of Medicine, Cardiff, UK
| | - Elizabeth A Thiele
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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28
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29
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Ekong R, Nellist M, Hoogeveen-Westerveld M, Wentink M, Panzer J, Sparagana S, Emmett W, Dawson NL, Malinge MC, Nabbout R, Carbonara C, Barberis M, Padovan S, Futema M, Plagnol V, Humphries SE, Migone N, Povey S. Variants Within TSC2 Exons 25 and 31 Are Very Unlikely to Cause Clinically Diagnosable Tuberous Sclerosis. Hum Mutat 2016; 37:364-70. [PMID: 26703369 PMCID: PMC4843954 DOI: 10.1002/humu.22951] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/07/2015] [Indexed: 11/16/2022]
Abstract
Inactivating mutations in TSC1 and TSC2 cause tuberous sclerosis complex (TSC). The 2012 international consensus meeting on TSC diagnosis and management agreed that the identification of a pathogenic TSC1 or TSC2 variant establishes a diagnosis of TSC, even in the absence of clinical signs. However, exons 25 and 31 of TSC2 are subject to alternative splicing. No variants causing clinically diagnosed TSC have been reported in these exons, raising the possibility that such variants would not cause TSC. We present truncating and in‐frame variants in exons 25 and 31 in three individuals unlikely to fulfil TSC diagnostic criteria and examine the importance of these exons in TSC using different approaches. Amino acid conservation analysis suggests significantly less conservation in these exons compared with the majority of TSC2 exons, and TSC2 expression data demonstrates that the majority of TSC2 transcripts lack exons 25 and/or 31 in many human adult tissues. In vitro assay of both exons shows that neither exon is essential for TSC complex function. Our evidence suggests that variants in TSC2 exons 25 or 31 are very unlikely to cause classical TSC, although a role for these exons in tissue/stage specific development cannot be excluded.
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Affiliation(s)
- Rosemary Ekong
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
| | - Mark Nellist
- Department of Clinical Genetics, Erasmus MC, Rotterdam, 3015CN, The Netherlands
| | | | - Marjolein Wentink
- Department of Clinical Genetics, Erasmus MC, Rotterdam, 3015CN, The Netherlands
| | - Jessica Panzer
- Department of Pediatrics, Division of Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, 19104-4318.,Department of Neurology Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, 19104
| | | | - Warren Emmett
- University College London Genetics Institute, Darwin building, Gower Street, London, WC1E 6BT, UK
| | - Natalie L Dawson
- Institute of Structural and Molecular Biology, University College London, London, WC1E 6BT, UK
| | - Marie Claire Malinge
- UF de Génétique Moléculaire, Département de Biochimie Génétique PBMM, Institut de Biologie en Santé CHU Angers, 49933 Angers, Cedex 9, France
| | - Rima Nabbout
- Centre de Référence des Epilepsies Rares, Hôpital Universitaire Necker - Enfants Malades, 75015, Paris, France
| | - Caterina Carbonara
- Neonatology and Neonatal Intensive Care Unit, S. Anna Hospital, 10126, Torino, Italy
| | - Marco Barberis
- Laboratory of Molecular Genetics, Azienda Ospedaliero Universitaria Città della Salute e della Scienza, Presidio OIRM S. Anna, 10126, Torino, Italy
| | - Sergio Padovan
- CNR-IBB UOS-TO at MBC, Molecular Biotechnology Center for University of Turin, 10126, Torino, Italy
| | - Marta Futema
- Centre for Cardiovascular Genetics, British Heart Foundation Laboratories, Institute of Cardiovascular Sciences, University College London, London, UK
| | - Vincent Plagnol
- University College London Genetics Institute, Darwin building, Gower Street, London, WC1E 6BT, UK
| | - Steve E Humphries
- Centre for Cardiovascular Genetics, British Heart Foundation Laboratories, Institute of Cardiovascular Sciences, University College London, London, UK
| | - Nicola Migone
- Department of Medical Sciences, University of Turin, 10126, Torino, Italy
| | - Sue Povey
- Department of Genetics, Evolution and Environment, University College London, London WC1E 6BT, UK
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30
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Curatolo P, Moavero R, Roberto D, Graziola F. Genotype/Phenotype Correlations in Tuberous Sclerosis Complex. Semin Pediatr Neurol 2015; 22:259-73. [PMID: 26706013 DOI: 10.1016/j.spen.2015.10.002] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by the development of widespread hamartomatous lesions in various organs, including brain, skin, kidneys, heart, and eyes. Central nervous system is almost invariably involved, with up to 85% of patients presenting with epilepsy, and at least half of patients having intellectual disability or other neuropsychiatric disorders including autism spectrum disorder. TSC is caused by the mutation in one of the 2 genes TSC1, at 9q34, and TSC2, at 16p13.3. They respectively encode for hamartin and tuberin, which form an intracellular complex inhibiting the mammalian target of rapamycin. Mammalian target of rapamycin overactivation following the genetic defect determines the cell growth and proliferation responsible for TSC-related lesions, as well as the alterations in neuronal excitability and synaptogenesis leading to epilepsy and neuropsychiatric disorders. A causative mutation for the disorder is identified in about 85% of patients with a clinical diagnosis of TSC. Mosaicism and technology limits likely explain most of the no mutation identified cases. This review confirms that patients with TSC2 mutations considered as a group usually present a more severe phenotype, characterized by higher number of tubers, earlier age at seizure onset and higher prevalence of intellectual disability. However, the clinical phenotype of the disease presents a high variability, thus making the prediction of the phenotype on an individual basis still challenging. The increasing application of new molecular techniques to subjects with TSC has the potential to significantly reduce the rate of patients with no mutation demonstrated and to identify an increasing higher number of mutations. This would hopefully allow a better characterization of higher risk mutations, which might help clinicians to plan individualized surveillance plans. Furthermore, the increasing availability of disease registries to collect clinical and genetics data of patients help to define more valid and clinically oriented genotype or phenotype correlations.
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Affiliation(s)
- Paolo Curatolo
- (⁎)Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital of Rome, Rome, Italy.
| | - Romina Moavero
- (⁎)Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital of Rome, Rome, Italy; Child Neurology Unit, Department of Neuroscience and Neurorehabilitation, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Denis Roberto
- (⁎)Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital of Rome, Rome, Italy
| | - Federica Graziola
- (⁎)Child Neurology and Psychiatry Unit, Systems Medicine Department, Tor Vergata University Hospital of Rome, Rome, Italy
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Wong HT, McCartney DL, Lewis JC, Sampson JR, Howe CJ, de Vries PJ. Intellectual ability in tuberous sclerosis complex correlates with predicted effects of mutations on TSC1 and TSC2 proteins. J Med Genet 2015; 52:815-22. [DOI: 10.1136/jmedgenet-2015-103154] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 08/29/2015] [Indexed: 12/13/2022]
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Curatolo P, Moavero R, de Vries PJ. Neurological and neuropsychiatric aspects of tuberous sclerosis complex. Lancet Neurol 2015; 14:733-45. [PMID: 26067126 DOI: 10.1016/s1474-4422(15)00069-1] [Citation(s) in RCA: 375] [Impact Index Per Article: 41.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 04/21/2015] [Accepted: 04/27/2015] [Indexed: 01/22/2023]
Abstract
Tuberous sclerosis (also known as tuberous sclerosis complex [TSC]) is a multisystem genetic disorder that affects almost every organ in the body. Mutations in the TSC1 or TSC2 genes lead to disruption of the TSC1-TSC2 intracellular protein complex, causing overactivation of the mammalian target of rapamycin (mTOR) protein complex. The surveillance and management guidelines and clinical criteria for tuberous sclerosis were revised in 2012, and mTOR inhibitors are now recommended as treatment options for subependymal giant cell astrocytomas and renal angiomyolipomas-two common features of the disease. However, most morbidity and mortality caused by tuberous sclerosis is associated with neurological and neuropsychiatric manifestations. Treatment of epilepsy associated with tuberous sclerosis remains a major challenge, with more than 60% of patients having ongoing seizures. Tuberous-sclerosis-associated neuropsychiatric disorders (TAND) are multilevel and occur in most individuals with the disorder, but are rarely assessed and treated. Clinical trials of mTOR inhibitors to treat seizures and TAND are underway. Management of the neurological and neuropsychiatric manifestations of the disorder should be coordinated with treatment of other organ systems. In view of the age-related expression of manifestations from infancy to adulthood, continuity of clinical care and ongoing monitoring is paramount, and particular attention is needed to plan transition of patient care from childhood to adult services.
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Affiliation(s)
- Paolo Curatolo
- Neuroscience Department, Child Neurology and Psychiatry Division, University Hospital of Tor Vergata, Rome, Italy.
| | - Romina Moavero
- Neuroscience Department, Child Neurology and Psychiatry Division, University Hospital of Tor Vergata, Rome, Italy; Neuroscience Department, Child Neurology Division, Bambino Gesù Children's Hospital, IRCCS, Rome, Italy
| | - Petrus J de Vries
- Division of Child and Adolescent Psychiatry, University of Cape Town, Cape Town, South Africa
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Kwiatkowski DJ, Palmer MR, Jozwiak S, Bissler J, Franz D, Segal S, Chen D, Sampson JR. Response to everolimus is seen in TSC-associated SEGAs and angiomyolipomas independent of mutation type and site in TSC1 and TSC2. Eur J Hum Genet 2015; 23:1665-72. [PMID: 25782670 PMCID: PMC4795200 DOI: 10.1038/ejhg.2015.47] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 01/17/2015] [Accepted: 01/27/2015] [Indexed: 12/18/2022] Open
Abstract
Tuberous sclerosis complex is an autosomal dominant disorder that occurs owing to inactivating mutations in either TSC1 or TSC2. Tuberous sclerosis complex-related tumors in the brain, such as subependymal giant cell astrocytoma, and in the kidney, such as angiomyolipoma, can cause significant morbidity and mortality. Recently, randomized clinical trials (EXIST-1 and EXIST-2) of everolimus for each of these tuberous sclerosis complex-associated tumors demonstrated the benefit of this drug, which blocks activated mammalian target of rapamycin complex 1. Here we report on the spectrum of mutations seen in patients treated during these trials and the association between mutation and response. TSC2 mutations were predominant among patients in both trials and were present in nearly all subjects with angiomyolipoma in whom a mutation was identified (97%), whereas TSC1 mutations were rare in those subjects (3%). The spectrum of mutations seen in each gene was similar to those previously reported. In both trials, there was no apparent association between mutation type or location within each gene and response to everolimus. Everolimus responses were also seen at a similar frequency for the 16–18% of patients in each trial in whom no mutation in either gene was identified. These observations confirm the strong association between TSC2 mutation and angiomyolipoma burden seen in previous studies, and they indicate that everolimus response occurs regardless of mutation type or location or when no mutation in TSC1 or TSC2 has been identified.
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Affiliation(s)
| | | | | | - John Bissler
- St Jude Children's Research Hospital, University of Tennessee Health Science Center, Memphis, TN, USA
| | - David Franz
- Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Scott Segal
- Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
| | - David Chen
- Novartis Pharmaceuticals Corporation, East Hanover, NJ, USA
| | - Julian R Sampson
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, UK
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Jansen AC. Careful clinical observation continues to improve understanding of the phenotype in individuals with tuberous sclerosis complex. Dev Med Child Neurol 2014; 56:1134-1135. [PMID: 25039834 DOI: 10.1111/dmcn.12537] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Anna C Jansen
- Pediatric Neurology Unit - UZ Brussel, Brussels, Belgium
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Tyburczy ME, Jozwiak S, Malinowska IA, Chekaluk Y, Pugh TJ, Wu CL, Nussbaum RL, Seepo S, Dzik T, Kotulska K, Kwiatkowski DJ. A shower of second hit events as the cause of multifocal renal cell carcinoma in tuberous sclerosis complex. Hum Mol Genet 2014; 24:1836-42. [PMID: 25432535 DOI: 10.1093/hmg/ddu597] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a genetic disorder characterized by seizures and tumor formation in multiple organs, mainly in the brain, skin, kidney, lung and heart. Renal cell carcinoma (RCC) occurs in ∼3% of TSC patients, and typically develops at age <50. Here we describe genetic findings in two TSC patients with multiple renal tumors, each of whom had the germline mutation TSC2 p.R905Q. The first (female) TSC patient had a left followed by a right nephrectomy at ages 24 and 27. Both kidneys showed multifocal TSC-associated papillary RCC (PRCC). Targeted, next-generation sequencing (NGS) analysis of TSC2 in five tumors (four from the left kidney, one from the right) showed loss of heterozygosity in one tumor, and four different TSC2 point mutations (p.E1351*, p.R1032*, p.R1713H, c.4178_4179delCT) in the other four samples. Only one of the 11 other tumors available from this patient had one of the TSC2 second hit mutations identified. Whole-exome analysis of the five tumors identified a very small number of additional mutated genes, with an average of 3.4 nonsilent coding, somatic mutations per tumor, none of which were seen in >1 tumor. The second (male) TSC patient had bilateral partial nephrectomies (both at age 36), with similar findings of multifocal PRCC. NGS analysis of TSC2 in two of these tumors identified a second hit mutation c.2355+1G>T in one sample that was not seen in other tumors. In conclusion, we report the first detailed genetic analysis of RCCs in TSC patients. Molecular studies indicate that tumors developed independently due to various second hit events, suggesting that these patients experienced a 'shower' of second hit mutations in TSC2 during kidney development leading to this severe phenotype.
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Affiliation(s)
- Magdalena E Tyburczy
- Division of Pulmonary Medicine and of Genetics, Brigham and Women's Hospital, Boston, MA, USA
| | | | - Izabela A Malinowska
- Division of Pulmonary Medicine and of Genetics, Brigham and Women's Hospital, Boston, MA, USA
| | - Yvonne Chekaluk
- Division of Pulmonary Medicine and of Genetics, Brigham and Women's Hospital, Boston, MA, USA
| | - Trevor J Pugh
- Princess Margaret Cancer Centre, University Health Network, Toronto, ON, Canada, Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Chin-Lee Wu
- Pathology Department, Massachusetts General Hospital, Boston, MA, USA
| | - Robert L Nussbaum
- Division of Genomic Medicine, Helen Diller Family Comprehensive Cancer Center and Institute for Human Genetics, University of California San Francisco, San Francisco, CA, USA
| | - Sara Seepo
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Tomasz Dzik
- Children's Memorial Health Institute of Warsaw, Warsaw, Poland
| | | | - David J Kwiatkowski
- Division of Pulmonary Medicine and of Genetics, Brigham and Women's Hospital, Boston, MA, USA,
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Delaney SP, Julian LM, Stanford WL. The neural crest lineage as a driver of disease heterogeneity in Tuberous Sclerosis Complex and Lymphangioleiomyomatosis. Front Cell Dev Biol 2014; 2:69. [PMID: 25505789 PMCID: PMC4243694 DOI: 10.3389/fcell.2014.00069] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 11/02/2014] [Indexed: 12/20/2022] Open
Abstract
Lymphangioleiomyomatosis (LAM) is a rare neoplastic disease, best characterized by the formation of proliferative nodules that express smooth muscle and melanocytic antigens within the lung parenchyma, leading to progressive destruction of lung tissue and function. The pathological basis of LAM is associated with Tuberous Sclerosis Complex (TSC), a multi-system disorder marked by low-grade tumors in the brain, kidneys, heart, eyes, lung and skin, arising from inherited or spontaneous germ-line mutations in either of the TSC1 or TSC2 genes. LAM can develop either in a patient with TSC (TSC-LAM) or spontaneously (S-LAM), and it is clear that the majority of LAM lesions of both forms are characterized by an inactivating mutation in either TSC1 or TSC2, as in TSC. Despite this genetic commonality, there is considerable heterogeneity in the tumor spectrum of TSC and LAM patients, the basis for which is currently unknown. There is extensive clinical evidence to suggest that the cell of origin for LAM, as well as many of the TSC-associated tumors, is a neural crest cell, a highly migratory cell type with extensive multi-lineage potential. Here we explore the hypothesis that the types of tumors that develop and the tissues that are affected in TSC and LAM are dictated by the developmental timing of TSC gene mutations, which determines the identities of the affected cell types and the size of downstream populations that acquire a mutation. We further discuss the evidence to support a neural crest origin for LAM and TSC tumors, and propose approaches for generating humanized models of TSC and LAM that will allow cell of origin theories to be experimentally tested. Identifying the cell of origin and developing appropriate humanized models is necessary to truly understand LAM and TSC pathology and to establish effective and long-lasting therapeutic approaches for these patients.
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Affiliation(s)
- Sean P Delaney
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada
| | - Lisa M Julian
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada
| | - William L Stanford
- Sprott Centre for Stem Cell Research, Regenerative Medicine Program, Ottawa Hospital Research Institute Ottawa, ON, Canada ; Faculty of Graduate and Postdoctoral Studies, University of Ottawa Ottawa, ON, Canada ; Department of Cellular and Molecular Medicine, University of Ottawa Ottawa, ON, Canada ; Department of Biochemistry, Microbiology, and Immunology, University of Ottawa Ottawa, ON, Canada
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Transgenic expression of the N525S-tuberin variant in Tsc2 mutant (Eker) rats causes dominant embryonic lethality. Sci Rep 2014; 4:5927. [PMID: 25088526 PMCID: PMC5379989 DOI: 10.1038/srep05927] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 06/19/2014] [Indexed: 01/05/2023] Open
Abstract
The Tsc2 product, tuberin, negatively regulates the mTOR pathway. We have exploited the Eker (Tsc2-mutant) rat system to analyse various Tsc2 mutations. Here, we focus on the N525S-Tsc2 variant (NSM), which is known to cause distinct symptoms in patients even though normal suppression of mTOR is observed. Unexpectedly, we were repeatedly unable to generate viable rats carrying the NSM transgene. Genotypic analysis revealed that most of the embryos carrying the transgene died around embryonic day after 14.5—similar to the stage of lethality observed for Eker homozygotes. Thus, the NSM transgene appeared to have a dominant lethal effect in our rat model. Further, no significant differences were observed for various signal transduction molecules in transiently expressed NSM cells compared to WT. These results indicate that a non-mTOR pathway, critical for embryogenesis, is being regulated by tuberin, providing a link between tuberin expression and the severity of Tsc2 mutation-related pathogenesis.
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Abstract
Tuberous sclerosis complex (TSC) is a genetic multisystem disorder characterized by widespread hamartomas in several organs, including the brain, heart, skin, eyes, kidney, lung, and liver. The affected genes are TSC1 and TSC2, encoding hamartin and tuberin respectively. The hamartin-tuberin complex inhibits the mammalian-target-of-Rapamycin (mTOR) pathway, which controls cell growth and proliferation. Variations in the distribution, number, size, and location of lesions cause the clinical syndrome to vary even between relatives. About 85% of children and adolescents with TSC have CNS complications, including epilepsy, cognitive impairment, challenging behavioral problems, and autism-like symptoms. Epilepsy generally begins during the first year of life, with focal seizures and spasms. The discovery of the mTOR pathway upregulation in TSC-associated lesions presents new possibilities for treatment strategy. Increasing understanding of the molecular abnormalities caused by TSC may enable improved management of the disease.
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Affiliation(s)
- P Curatolo
- Department of Neuroscience, Pediatric Neurology Unit, Tor Vergata University of Rome, Rome, Italy.
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Franz DN. Everolimus in the treatment of subependymal giant cell astrocytomas, angiomyolipomas, and pulmonary and skin lesions associated with tuberous sclerosis complex. Biologics 2013; 7:211-21. [PMID: 24143074 PMCID: PMC3797614 DOI: 10.2147/btt.s25095] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant genetic disorder caused by inactivating mutations in either the TSC1 or TSC2 genes. It is characterized by the development of multiple, benign tumors in several organs throughout the body. Lesions occur in the brain, kidneys, heart, liver, lungs, and skin and result in seizures and epilepsy, mental retardation, autism, and renal and pulmonary organ system dysfunction, as well as other complications. Elucidation of the molecular pathways and etiological factors responsible for causing TSC has led to a paradigm shift in the management and treatment of the disease. TSC1 or TSC2 mutations lead to constitutive upregulation of the mammalian target of rapamycin pathway, which affects many cellular processes involved in tumor growth. By targeting mammalian target of rapamycin with everolimus, an orally active rapamycin derivative, clinically meaningful and statistically significant reductions in tumor burden have been achieved for the main brain (subependymal giant cell astrocytoma) and renal manifestations (angiomyolipoma) associated with TSC. This review provides an overview of TSC, everolimus, and the clinical trials that led to its approval for the treatment of TSC-associated subependymal giant cell astrocytoma and renal angiomyolipoma.
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Affiliation(s)
- David Neal Franz
- Department of Pediatrics, Tuberous Sclerosis Clinic, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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Gipson TT, Gerner G, Wilson MA, Blue ME, Johnston MV. Potential for treatment of severe autism in tuberous sclerosis complex. World J Clin Pediatr 2013; 2:16-25. [PMID: 25254170 PMCID: PMC4145642 DOI: 10.5409/wjcp.v2.i3.16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2013] [Revised: 04/30/2013] [Accepted: 06/04/2013] [Indexed: 02/06/2023] Open
Abstract
The Food and Drug Administration (FDA) has approved two mechanism-based treatments for tuberous sclerosis complex (TSC)-everolimus and vigabatrin. However, these treatments have not been systematically studied in individuals with TSC and severe autism. The aim of this review is to identify the clinical features of severe autism in TSC, applicable preclinical models, and potential barriers that may warrant strategic planning in the design phase of clinical trial development. A comprehensive search strategy was formed and searched across PubMed, Embase and SCOPUS from their inception to 2/21/12, 3/16/12, and 3/12/12 respectively. After the final search date, relevant, updated articles were selected from PubMed abstracts generated electronically and emailed daily from PubMed. The references of selected articles were searched, and relevant articles were selected. A search of clinicaltrials.gov was completed using the search term “TSC” and “tuberous sclerosis complex”. Autism has been reported in as many as 60% of individuals with TSC; however, review of the literature revealed few data to support clear classification of the severity of autism in TSC. Variability was identified in the diagnostic approach, assessment of cognition, and functional outcome among the reviewed studies and case reports. Objective outcome measures were not used in many early studies; however, diffusion tensor imaging of white matter, neurophysiologic variability in infantile spasms, and cortical tuber subcategories were examined in recent studies and may be useful for objective classification of TSC in future studies. Mechanism-based treatments for TSC are currently available. However, this literature review revealed two potential barriers to successful design and implementation of clinical trials in individuals with severe autism-an unclear definition of the population and lack of validated outcome measures. Recent studies of objective outcome measures in TSC and further study of applicable preclinical models present an opportunity to overcome these barriers.
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Mutational analysis of TSC1 and TSC2 in Japanese patients with tuberous sclerosis complex revealed higher incidence of TSC1 patients than previously reported. J Hum Genet 2013; 58:216-25. [PMID: 23389244 DOI: 10.1038/jhg.2013.3] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant disorder characterized by multiple hamartias and hamartomas involving throughout the body. To date, many TSC1 and TSC2 mutations have been reported all over the world, however, few TSC mutation studies have been performed in the Japanese population, and genetic characteristics of Japanese TSC patients are not yet clear. In this study, we analyzed TSC1 and TSC2 in 57 Japanese patients with TSC (8 familial and 49 sporadic; 46 definite and 11 suspect TSC) and identified 31 mutations including 11 TSC1 mutations (two familial and nine sporadic; all definite TSC) and 20 TSC2 mutations (2 familial and 18 sporadic; 19 definite and 1 suspect TSC). We also reviewed all Japanese TSC mutations previously reported. Our study demonstrates significantly higher incidence (P=0.007) of TSC1 mutations among sporadic TSC patients in the Japanese population compared with US and European studies. No differences emerged in mutation distributions and types in precedent studies, excepting low frequency of the TSC2 nonsense mutation. Comparing clinical manifestations, developmental delay and/or mental retardation were milder in TSC1 patients than TSC2 patients for its frequency (P=0.032) and severity (P=0.015); however, no other symptoms were clearly different.
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Central TSC2 missense mutations are associated with a reduced risk of infantile spasms. Epilepsy Res 2013; 103:83-7. [DOI: 10.1016/j.eplepsyres.2012.07.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 06/25/2012] [Accepted: 07/03/2012] [Indexed: 12/20/2022]
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Hoogeveen-Westerveld M, van Unen L, van den Ouweland A, Halley D, Hoogeveen A, Nellist M. The TSC1-TSC2 complex consists of multiple TSC1 and TSC2 subunits. BMC BIOCHEMISTRY 2012; 13:18. [PMID: 23006675 PMCID: PMC3517901 DOI: 10.1186/1471-2091-13-18] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 09/21/2012] [Indexed: 01/05/2023]
Abstract
Background Mutations to the TSC1 and TSC2 genes cause the disease tuberous sclerosis complex. The TSC1 and TSC2 gene products form a protein complex that integrates multiple metabolic signals to regulate the activity of the target of rapamycin (TOR) complex 1 (TORC1) and thereby control cell growth. Here we investigate the quaternary structure of the TSC1-TSC2 complex by gel filtration and coimmunoprecipitation. Results TSC1 and TSC2 co-eluted in high molecular weight fractions by gel filtration. Coimmunoprecipitation of distinct tagged TSC1 and TSC2 isoforms demonstrated that TSC1-TSC2 complexes contain multiple TSC1 and TSC2 subunits. Conclusions TSC1 and TSC2 interact to form large complexes containing multiple TSC1 and TSC2 subunits.
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Yuan E, Tsai PT, Greene-Colozzi E, Sahin M, Kwiatkowski DJ, Malinowska IA. Graded loss of tuberin in an allelic series of brain models of TSC correlates with survival, and biochemical, histological and behavioral features. Hum Mol Genet 2012; 21:4286-300. [PMID: 22752306 DOI: 10.1093/hmg/dds262] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a neurodevelopmental disorder with prominent brain manifestations due to mutations in either TSC1 or TSC2. Here, we describe novel mouse brain models of TSC generated using conditional hypomorphic and null alleles of Tsc2 combined with the neuron-specific synapsin I cre (SynIcre) allele. This allelic series of homozygous conditional hypomorphic alleles (Tsc2(c-del3/c-del3)SynICre(+)) and heterozygote null/conditional hypomorphic alleles (Tsc2(k/c-del3)SynICre(+)) achieves a graded reduction in expression of Tsc2 in neurons in vivo. The mice demonstrate a progressive neurologic phenotype including hunchback, hind limb clasp, reduced survival and brain and cortical neuron enlargement that correlates with a graded reduction in expression of Tsc2 in the two sets of mice. Both models also showed behavioral abnormalities in anxiety, social interaction and learning assays, which correlated with Tsc2 protein levels as well. The observations demonstrate that there are graded biochemical, cellular and clinical/behavioral effects that are proportional to the extent of reduction in Tsc2 expression in neurons. Further, they suggest that some patients with milder manifestations of TSC may be due to persistent low-level expression of functional protein from their mutant allele. In addition, they point to the potential clinical benefit of strategies to raise TSC2 protein expression from the wild-type allele by even modest amounts.
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Affiliation(s)
- Elizabeth Yuan
- Department of Medicine, Brigham and Women’s Hospital, Boston, MA 02115, USA
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van Eeghen AM, Black ME, Pulsifer MB, Kwiatkowski DJ, Thiele EA. Genotype and cognitive phenotype of patients with tuberous sclerosis complex. Eur J Hum Genet 2011; 20:510-5. [PMID: 22189265 DOI: 10.1038/ejhg.2011.241] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is an autosomal dominant, multisystem disorder, which affects 1 in 6000 people. About half of these patients are affected by mental retardation, which has been associated with TSC2 mutations, epilepsy severity and tuber burden. The bimodal intelligence distribution in TSC populations suggests the existence of subgroups with distinct pathophysiologies, which remain to be identified. Furthermore, it is unknown if heterozygous germline mutations in TSC2 can produce the neurocognitive phenotype of TSC independent of epilepsy and tubers. Genotype-phenotype correlations may help to determine risk profiles and select patients for targeted treatments. A retrospective chart review was performed, including a large cohort of 137 TSC patients who received intelligence assessment and genetic mutation analysis. The distribution of intellectual outcomes was investigated for selected genotypes. Genotype-neurocognitive phenotype correlations were performed and associations between specific germline mutations and intellectual outcomes were compared. Results showed that TSC1 mutations in the tuberin interaction domain were significantly associated with lower intellectual outcomes (P<0.03), which was also the case for TSC2 protein-truncating and hamartin interaction domain mutations (both P<0.05). TSC2 missense mutations and small in-frame deletions were significantly associated with higher IQ/DQs (P<0.05). Effects related to the mutation location within the TSC2 gene were found. These findings suggest that TSC2 protein-truncating mutations and small in-frame mutations are associated with distinctly different intelligence profiles, providing further evidence that different types and locations of TSC germline mutations may be associated with distinct neurocognitive phenotypes.
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Affiliation(s)
- Agnies M van Eeghen
- Department of Neurology, The Carol and James Herscot Center for Tuberous Sclerosis Complex, Massachusetts General Hospital, Boston, MA, USA
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Chévere-Torres I, Kaphzan H, Bhattacharya A, Kang A, Maki JM, Gambello MJ, Arbiser JL, Santini E, Klann E. Metabotropic glutamate receptor-dependent long-term depression is impaired due to elevated ERK signaling in the ΔRG mouse model of tuberous sclerosis complex. Neurobiol Dis 2011; 45:1101-10. [PMID: 22198573 DOI: 10.1016/j.nbd.2011.12.028] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2011] [Revised: 11/08/2011] [Accepted: 12/08/2011] [Indexed: 11/28/2022] Open
Abstract
Tuberous sclerosis complex (TSC) and fragile X syndrome (FXS) are caused by mutations in negative regulators of translation. FXS model mice exhibit enhanced metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD). Therefore, we hypothesized that a mouse model of TSC, ΔRG transgenic mice, also would exhibit enhanced mGluR-LTD. We measured the impact of TSC2-GAP mutations on the mTORC1 and ERK signaling pathways and protein synthesis-dependent hippocampal synaptic plasticity in ΔRG transgenic mice. These mice express a dominant/negative TSC2 that binds to TSC1, but has a deletion and substitution mutation in its GAP-domain, resulting in inactivation of the complex. Consistent with previous studies of several other lines of TSC model mice, we observed elevated S6 phosphorylation in the brains of ΔRG mice, suggesting upregulated translation. Surprisingly, mGluR-LTD was not enhanced, but rather was impaired in the ΔRG transgenic mice, indicating that TSC and FXS have divergent synaptic plasticity phenotypes. Similar to patients with TSC, the ΔRG transgenic mice exhibit elevated ERK signaling. Moreover, the mGluR-LTD impairment displayed by the ΔRG transgenic mice was rescued with the MEK-ERK inhibitor U0126. Our results suggest that the mGluR-LTD impairment observed in ΔRG mice involves aberrant TSC1/2-ERK signaling.
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Impaired social interactions and motor learning skills in tuberous sclerosis complex model mice expressing a dominant/negative form of tuberin. Neurobiol Dis 2011; 45:156-64. [PMID: 21827857 DOI: 10.1016/j.nbd.2011.07.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 06/23/2011] [Accepted: 07/23/2011] [Indexed: 11/20/2022] Open
Abstract
Tuberous sclerosis complex (TSC) is a genetic disorder characterized by the development of hamartomas in multiple organs. Neurological manifestation includes cortical dysplasia, epilepsy, and cognitive deficits such as mental impairment and autism. We measured the impact of TSC2-GAP mutations on cognitive processes and behavior in, ΔRG transgenic mice that express a dominant/negative TSC2 that binds to TSC1, but has mutations affecting its GAP domain and its rabaptin-5 binding motif, resulting in inactivation of the TSC1/2 complex. We performed a behavioral characterization of the ΔRG transgenic mice and found that they display mild, but significant impairments in social behavior and rotarod motor learning. These findings suggest that the ΔRG transgenic mice recapitulate some behavioral abnormalities observed in human TSC patients.
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Seibert D, Hong CH, Takeuchi F, Olsen C, Hathaway O, Moss J, Darling TN. Recognition of tuberous sclerosis in adult women: delayed presentation with life-threatening consequences. Ann Intern Med 2011; 154:806-13, W-294. [PMID: 21690595 PMCID: PMC3367307 DOI: 10.7326/0003-4819-154-12-201106210-00008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Tuberous sclerosis complex (TSC) is associated with tumor development in the brain, retina, kidney, skin, heart, and lung. Seizures, intellectual disability, and characteristic skin lesions commonly manifest in early childhood, but some findings, notably renal angiomyolipomas and pulmonary lymphangioleiomyomatosis (LAM), emerge later, placing adults with undiagnosed TSC at increased risk for morbidity and mortality. OBJECTIVE To describe the clinical presentation and severity of TSC in adult women. DESIGN Retrospective cohort study. SETTING National Institutes of Health Clinical Center, Bethesda, Maryland, 1995 to 2010. PATIENTS 79 women aged 18 years or older who were enrolled in an observational cohort study of TSC to evaluate disease manifestations. MEASUREMENTS History, physical examination, pulmonary function testing, chest radiography, abdominal computed tomography, high-resolution chest computed tomography, and brain magnetic resonance imaging were used to evaluate patients. RESULTS Among the 45 patients who received a diagnosis of TSC in adulthood, 21 presented with symptoms due to LAM, 19 with renal angiomyolipomas, and 10 with seizures. Of the 45 patients, 30 met clinical criteria for TSC in childhood that remained undiagnosed for a median of 21.5 years and 15 were older than 18 years before meeting the clinical criteria for TSC. Patients diagnosed in adulthood and those diagnosed in childhood had similar occurrences of pneumothorax, shortness of breath, hemoptysis, nephrectomy, and death. LIMITATION No men were included in the study, and selection was biased toward patients having pulmonary LAM. CONCLUSION Women who received a TSC diagnosis in adulthood had minimal morbidity during childhood but were still at risk for life-threatening pulmonary and renal manifestations. PRIMARY FUNDING SOURCE Intramural Research Program, National Institutes of Health, National Heart, Lung, and Blood Institute.
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Affiliation(s)
- Diane Seibert
- Department of Dermatology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA
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Wentink M, Nellist M, Hoogeveen-Westerveld M, Zonnenberg B, van der Kolk D, van Essen T, Park SM, Woods G, Cohn-Hokke P, Brussel W, Smeets E, Brooks A, Halley D, van den Ouweland A, Maat-Kievit A. Functional characterization of the TSC2 c.3598C>T (p.R1200W) missense mutation that co-segregates with tuberous sclerosis complex in mildly affected kindreds. Clin Genet 2011; 81:453-61. [DOI: 10.1111/j.1399-0004.2011.01648.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Hoogeveen-Westerveld M, Wentink M, van den Heuvel D, Mozaffari M, Ekong R, Povey S, den Dunnen JT, Metcalfe K, Vallee S, Krueger S, Bergoffen J, Shashi V, Elmslie F, Kwiatkowski D, Sampson J, Vidales C, Dzarir J, Garcia-Planells J, Dies K, Maat-Kievit A, van den Ouweland A, Halley D, Nellist M. Functional assessment of variants in the TSC1 and TSC2 genes identified in individuals with Tuberous Sclerosis Complex. Hum Mutat 2011; 32:424-35. [PMID: 21309039 DOI: 10.1002/humu.21451] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Accepted: 01/06/2011] [Indexed: 11/10/2022]
Abstract
The effects of missense changes and small in-frame deletions and insertions on protein function are not easy to predict, and the identification of such variants in individuals at risk of a genetic disease can complicate genetic counselling. One option is to perform functional tests to assess whether the variants affect protein function. We have used this strategy to characterize variants identified in the TSC1 and TSC2 genes in individuals with, or suspected of having, Tuberous Sclerosis Complex (TSC). Here we present an overview of our functional studies on 45 TSC1 and 107 TSC2 variants. Using a standardized protocol we classified 16 TSC1 variants and 70 TSC2 variants as pathogenic. In addition we identified eight putative splice site mutations (five TSC1 and three TSC2). The remaining 24 TSC1 and 34 TSC2 variants were classified as probably neutral.
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