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An Analysis of Phenotype and Genotype in a Large Cohort of Chinese Children with Angelman Syndrome. Genes (Basel) 2022; 13:genes13081447. [PMID: 36011358 PMCID: PMC9408022 DOI: 10.3390/genes13081447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/01/2022] [Accepted: 08/11/2022] [Indexed: 11/17/2022] Open
Abstract
Angelman syndrome (AS) is a neurodevelopmental genetic disorder, but there has been limited analysis of a large cohort of Chinese children with Angelman syndrome. This study aims to assess the phenotype and genotype of Chinese children with Angelman syndrome. We retrospectively analyzed data through a detailed online survey combined with an on-site study. Furthermore, phenotype analysis stratified by deletion and non-deletion groups was carried out. The responses of family members of 695 individuals with AS revealed that 577 patients (83.02%) had maternal deletions, 65 patients (9.35%) carried UBE3A mutations, 31 (4.46%) patients had UPD15pat (one patient with UPD15pat constituted by a mosaic), 10 patients (1.44%) had imprinting defects and 12 (1.58%) patients only showed abnormal methylation without further detection. We identified 50 different pathogenic variants in this cohort, although 18 of these variants were unreported. Recurrent variant c.2507_2510del (p.K836Rfs*4) was found in 7 patients. In the deletion group, patients were diagnosed at an earlier age, had a more severe clinical phenotype, a higher rate of epilepsy with more multiple seizure types, and more frequently combined medication. Strabismus and sleep disturbances were both common in deletion and non-deletion groups. The top three resources invested in caring for AS children are: daily involvement in patient care, rehabilitation cost, and anti-epileptic treatment. Our study showed the genetic composition of Chinese children with 83.02% of maternal deletions, and the mutation spectrum for UBE3A variants was expanded. Developmental outcomes are associated with genotype, and this was confirmed by deletion patients having a worse clinical phenotype and complex epilepsy.
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2
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Weston KP, Gao X, Zhao J, Kim KS, Maloney SE, Gotoff J, Parikh S, Leu YC, Wu KP, Shinawi M, Steimel JP, Harrison JS, Yi JJ. Identification of disease-linked hyperactivating mutations in UBE3A through large-scale functional variant analysis. Nat Commun 2021; 12:6809. [PMID: 34815418 PMCID: PMC8635412 DOI: 10.1038/s41467-021-27156-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 11/01/2021] [Indexed: 12/03/2022] Open
Abstract
The mechanisms that underlie the extensive phenotypic diversity in genetic disorders are poorly understood. Here, we develop a large-scale assay to characterize the functional valence (gain or loss-of-function) of missense variants identified in UBE3A, the gene whose loss-of-function causes the neurodevelopmental disorder Angelman syndrome. We identify numerous gain-of-function variants including a hyperactivating Q588E mutation that strikingly increases UBE3A activity above wild-type UBE3A levels. Mice carrying the Q588E mutation exhibit aberrant early-life motor and communication deficits, and individuals possessing hyperactivating UBE3A variants exhibit affected phenotypes that are distinguishable from Angelman syndrome. Additional structure-function analysis reveals that Q588 forms a regulatory site in UBE3A that is conserved among HECT domain ubiquitin ligases and perturbed in various neurodevelopmental disorders. Together, our study indicates that excessive UBE3A activity increases the risk for neurodevelopmental pathology and suggests that functional variant analysis can help delineate mechanistic subtypes in monogenic disorders. UBE3A gene dysregulation is associated with neurodevelopmental disorders, but predicting the function of UBE3A variants remains difficult. The authors use a high-throughput assay to categorize variants by functional activity, and show that UBE3A hyperactivity increases the risk of neurodevelopmental disease.
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Affiliation(s)
- Kellan P Weston
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Xiaoyi Gao
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jinghan Zhao
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Kwang-Soo Kim
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Susan E Maloney
- Department of Psychiatry, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Jill Gotoff
- Department of Pediatrics, Geisinger Medical Center, Danville, PA, 17822, USA
| | - Sumit Parikh
- Department of Neurogenetics, Neurosciences Institute, Cleveland Clinic, Cleveland, OH, 44106, USA
| | - Yen-Chen Leu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Kuen-Phon Wu
- Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan
| | - Marwan Shinawi
- Division of Genetics and Genomic Medicine, Department of Pediatrics, St. Louis Children's Hospital, Washington University School of Medicine, St. Louis, MO, 63110, USA
| | - Joshua P Steimel
- Deparment of Mechanical Engineering, University of the Pacific, Stockton, CA, 95211, USA
| | - Joseph S Harrison
- Department of Chemistry, University of the Pacific, Stockton, CA, 95211, USA
| | - Jason J Yi
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, 63110, USA.
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3
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Bossuyt SNV, Punt AM, de Graaf IJ, van den Burg J, Williams MG, Heussler H, Elgersma Y, Distel B. Loss of nuclear UBE3A activity is the predominant cause of Angelman syndrome in individuals carrying UBE3A missense mutations. Hum Mol Genet 2021; 30:430-442. [PMID: 33607653 PMCID: PMC8101352 DOI: 10.1093/hmg/ddab050] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/16/2022] Open
Abstract
Angelman syndrome (AS) is a severe neurodevelopmental disorder caused by deletion (~75%) or mutation (~10%) of the ubiquitin E3 ligase A (UBE3A) gene, which encodes a HECT type E3 ubiquitin protein ligase. Although the critical substrates of UBE3A are unknown, previous studies have suggested a critical role of nuclear UBE3A in AS pathophysiology. Here, we investigated to what extent UBE3A missense mutations disrupt UBE3A subcellular localization as well as catalytic activity, stability and protein folding. Our functional screen of 31 UBE3A missense mutants revealed that UBE3A mislocalization is the predominant cause of UBE3A dysfunction, accounting for 55% of the UBE3A mutations tested. The second major cause (29%) is a loss of E3-ubiquitin ligase activity, as assessed in an Escherichia coli in vivo ubiquitination assay. Mutations affecting catalytic activity are found not only in the catalytic HECT domain, but also in the N-terminal half of UBE3A, suggesting an important contribution of this N-terminal region to its catalytic potential. Together, our results show that loss of nuclear UBE3A E3 ligase activity is the predominant cause of UBE3A-linked AS. Moreover, our functional analysis screen allows rapid assessment of the pathogenicity of novel UBE3A missense variants which will be of particular importance when treatments for AS become available.
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Affiliation(s)
- Stijn N V Bossuyt
- Department of Medical Biochemistry, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - A Mattijs Punt
- Department of Clinical Genetics and Department of Neuroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands.,ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC, 3015, 3015 CN, Rotterdam, The Netherlands
| | - Ilona J de Graaf
- Department of Medical Biochemistry, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Janny van den Burg
- Department of Medical Biochemistry, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands
| | - Mark G Williams
- Mater Research Institute, Faculty of Medicine, The University of Queensland, 4101, South Brisbane, Queensland, Australia
| | - Helen Heussler
- Mater Research Institute, Faculty of Medicine, The University of Queensland, 4101, South Brisbane, Queensland, Australia.,Child Development Program, Queensland Children's Hospital, 4101, South Brisbane, Queensland, Australia.,Child Health Research Centre, The University of Queensland, 4101, South Brisbane, Queensland, Australia
| | - Ype Elgersma
- Department of Clinical Genetics and Department of Neuroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands.,ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC, 3015, 3015 CN, Rotterdam, The Netherlands
| | - Ben Distel
- Department of Medical Biochemistry, Amsterdam UMC, University of Amsterdam, 1105 AZ, Amsterdam, The Netherlands.,Department of Clinical Genetics and Department of Neuroscience, Erasmus MC, 3015 GD Rotterdam, The Netherlands.,ENCORE Expertise Center for Neurodevelopmental Disorders, Erasmus MC, 3015, 3015 CN, Rotterdam, The Netherlands
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4
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Geerts‐Haages A, Bossuyt SNV, den Besten I, Bruggenwirth H, van der Burgt I, Yntema HG, Punt AM, Brooks A, Elgersma Y, Distel B, Valstar M. A novel UBE3A sequence variant identified in eight related individuals with neurodevelopmental delay, results in a phenotype which does not match the clinical criteria of Angelman syndrome. Mol Genet Genomic Med 2020; 8:e1481. [PMID: 32889787 PMCID: PMC7667313 DOI: 10.1002/mgg3.1481] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 07/10/2020] [Accepted: 07/31/2020] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND Loss of functional UBE3A, an E3 protein ubiquitin ligase, causes Angelman syndrome (AS), a neurodevelopmental disorder characterized by severe developmental delay, speech impairment, epilepsy, movement or balance disorder, and a characteristic behavioral pattern. We identified a novel UBE3A sequence variant in a large family with eight affected individuals, who did not meet the clinical AS criteria. METHODS Detailed clinical examination and genetic analysis was performed to establish the phenotypic diversity and the genetic cause. The function of the mutant UBE3A protein was assessed with respect to its subcellular localization, stability, and E3 ubiquitin ligase activity. RESULTS All eight affected individuals showed the presence of a novel maternally inherited UBE3A sequence variant (NM_130838.4(UBE3A):c.1018-1020del, p.(Asn340del), which is in line with a genetic AS diagnosis. Although they presented with moderate to severe intellectual disability, the phenotype did not match the clinical criteria for AS. In line with this, functional analysis of the UBE3A p.Asn340del mutant protein revealed no major deficits in UBE3A protein localization, stability, or E3 ubiquitin ligase activity. CONCLUSION The p.(Asn340del) mutant protein behaves distinctly different from previously described AS-linked missense mutations in UBE3A, and causes a phenotype that is markedly different from AS. This study further extends the range of phenotypes that are associated with UBE3A loss, duplication, or mutation.
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Affiliation(s)
- Amber Geerts‐Haages
- Intellectual Disability MedicineDepartment of General PracticeErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Stijn N. V. Bossuyt
- Department of Medical BiochemistryAmsterdam UMC, University of AmsterdamAmsterdamThe Netherlands
| | - Inge den Besten
- Intellectual Disability MedicineDepartment of General PracticeErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Hennie Bruggenwirth
- Department of Clinical GeneticsErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Ineke van der Burgt
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
| | - Helger G. Yntema
- Department of Human GeneticsRadboud University Medical CenterNijmegenThe Netherlands
| | - A. Mattijs Punt
- Department of NeuroscienceErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Alice Brooks
- Department of Clinical GeneticsErasmus MC University Medical CenterRotterdamThe Netherlands
- ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Ype Elgersma
- Department of NeuroscienceErasmus MC University Medical CenterRotterdamThe Netherlands
- ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Ben Distel
- Department of Medical BiochemistryAmsterdam UMC, University of AmsterdamAmsterdamThe Netherlands
- Department of NeuroscienceErasmus MC University Medical CenterRotterdamThe Netherlands
- ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdamThe Netherlands
| | - Marlies Valstar
- Intellectual Disability MedicineDepartment of General PracticeErasmus MC University Medical CenterRotterdamThe Netherlands
- ENCORE Expertise Center for Neurodevelopmental DisordersErasmus MC University Medical CenterRotterdamThe Netherlands
- ASVZ, Medical DepartmentCare and Service Centre for People with Intellectual DisabilitiesSliedrechtThe Netherlands
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5
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Gawel K, Langlois M, Martins T, van der Ent W, Tiraboschi E, Jacmin M, Crawford AD, Esguerra CV. Seizing the moment: Zebrafish epilepsy models. Neurosci Biobehav Rev 2020; 116:1-20. [PMID: 32544542 DOI: 10.1016/j.neubiorev.2020.06.010] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 04/20/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022]
Abstract
Zebrafish are now widely accepted as a valuable animal model for a number of different central nervous system (CNS) diseases. They are suitable both for elucidating the origin of these disorders and the sequence of events culminating in their onset, and for use as a high-throughput in vivo drug screening platform. The availability of powerful and effective techniques for genome manipulation allows the rapid modelling of different genetic epilepsies and of conditions with seizures as a core symptom. With this review, we seek to summarize the current knowledge about existing epilepsy/seizures models in zebrafish (both pharmacological and genetic) and compare them with equivalent rodent and human studies. New findings obtained from the zebrafish models are highlighted. We believe that this comprehensive review will highlight the value of zebrafish as a model for investigating different aspects of epilepsy and will help researchers to use these models to their full extent.
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Affiliation(s)
- Kinga Gawel
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Department of Experimental and Clinical Pharmacology, Medical University of Lublin, Jaczewskiego St. 8b, 20-090, Lublin, Poland
| | | | - Teresa Martins
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Wietske van der Ent
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway
| | - Ettore Tiraboschi
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway; Neurophysics Group, Center for Mind/Brain Sciences, University of Trento, Piazza Manifattura 1, Building 14, 38068, Rovereto, TN, Italy
| | - Maxime Jacmin
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg
| | - Alexander D Crawford
- Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Belval, Luxembourg; Faculty of Veterinary Medicine, Norwegian University of Life Sciences (NMBU), Oslo, Norway
| | - Camila V Esguerra
- Chemical Neuroscience Group, Centre for Molecular Medicine Norway (NCMM), University of Oslo, Gaustadalléen 21, Forskningsparken, 0349, Oslo, Norway.
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6
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Molecular-Genetic Diagnostics of Angelman Syndrome – The Bulgarian Experience. ACTA MEDICA BULGARICA 2020. [DOI: 10.2478/amb-2020-0002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Objective: The aim of the study was to determine the molecular mechanisms of mutagenesis in Bulgarian patients with Angelman syndrome (AS). AS is a severe neurodevelopmental disorder caused by loss of expression in brain of the maternally inherited UBE3A gene as a result of various 15q11.2-q13 alterations.
Material and Methods: In total 24 patients (11 boys, 13 girls) from 22 unrelated families with suspected clinical diagnosis AS were analysed. We used methylation specific PCR, multiplex ligation-dependent probe amplification, methylation sensitive MLPA, and direct sequencing of the UBE3A gene.
Results: In 9 families (41%) pathogenic mutations were detected, which confirmed the clinical diagnosis on а molecular-genetic level. In 4 (44%) of these families we found 15q11-q13 region deletion with breakpoints BP1-BP3 or BP2-BP3. In 1 (11%) of the families we found imprinting defect: deletion of the AS-SRO regulatory region (part of the PWS-AS imprinting center). In 1 (11%) of the families we detected a rare finding – paternal uniparental disomy of chromosome 15. In 3 (33%) of the families diff erent point mutations in the UBE3A gene were detected: two novel missence mutations c.488T > C; p.Leu163Ser and c.1832A > T; p.Gln611Leu, and one known frameshift mutation c.2576_2579delAAGA; p.Lys859Argfs*4.
Conclusion: The obtained results helped us to develop a systematic diagnostic algorithm in order to provide proper diagnosis for the patients with AS. Combining excellent knowledge of the molecular mechanisms of mutagenesis and proper molecular-genetic testing approaches is a cornerstone in the management of AS patients, ensuring AS families would receive both adequate genetic counseling and prophylaxis of the disease in the future.
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7
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Buiting K, Williams C, Horsthemke B. Angelman syndrome — insights into a rare neurogenetic disorder. Nat Rev Neurol 2016; 12:584-93. [DOI: 10.1038/nrneurol.2016.133] [Citation(s) in RCA: 199] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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8
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Noor A, Dupuis L, Mittal K, Lionel AC, Marshall CR, Scherer SW, Stockley T, Vincent JB, Mendoza-Londono R, Stavropoulos DJ. 15q11.2 Duplication Encompassing Only the UBE3A Gene Is Associated with Developmental Delay and Neuropsychiatric Phenotypes. Hum Mutat 2016; 36:689-93. [PMID: 25884337 DOI: 10.1002/humu.22800] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 03/31/2015] [Indexed: 01/08/2023]
Abstract
Duplications of chromosome region 15q11-q13 with the maternal imprint are associated with a wide spectrum of neuropsychiatric disorders, including autism spectrum disorders, developmental delay, learning difficulties, schizophrenia, and seizures. These observations suggest there is a dosage-sensitive imprinted gene or genes within this region that explains the increased risk for neuropsychiatric phenotypes. We present a female patient with developmental delay in whom we identified a maternally inherited 129-Kb duplication in chromosome region 15q11.2 encompassing only the UBE3A gene. Expression analysis in cultured fibroblasts confirmed overexpression of UBE3A in the proband, compared with age- and sex-matched controls. We further tested segregation of this duplication in four generations and found it segregated with neuropsychiatric phenotypes. Our study shows for the first time clinical features associated with overexpression of UBE3A in humans and underscores the significance of this gene in the phenotype of individuals with 15q11-q13 duplication.
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Affiliation(s)
- Abdul Noor
- Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Pathology and Laboratory Medicine, Mount Sinai Hospital Joseph and Wolf Lebovic Health Complex, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Lucie Dupuis
- The Hospital for Sick Children, Department of Pediatrics, Division of Clinical and Metabolic Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Kirti Mittal
- Molecular Neuropsychiatry & Development Lab, The Campbell Family Brain Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Anath C Lionel
- The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Christian R Marshall
- Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,McLaughlin Centre, University of Toronto, Toronto, Ontario, Canada
| | - Stephen W Scherer
- The Centre for Applied Genomics and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario, Canada.,McLaughlin Centre, University of Toronto, Toronto, Ontario, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Tracy Stockley
- Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - John B Vincent
- Molecular Neuropsychiatry & Development Lab, The Campbell Family Brain Research Institute, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
| | - Roberto Mendoza-Londono
- The Hospital for Sick Children, Department of Pediatrics, Division of Clinical and Metabolic Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Dimitri J Stavropoulos
- Department of Pediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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9
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Yi JJ, Berrios J, Newbern JM, Snider WD, Philpot BD, Hahn KM, Zylka MJ. An Autism-Linked Mutation Disables Phosphorylation Control of UBE3A. Cell 2015; 162:795-807. [PMID: 26255772 DOI: 10.1016/j.cell.2015.06.045] [Citation(s) in RCA: 116] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 03/06/2015] [Accepted: 06/18/2015] [Indexed: 12/31/2022]
Abstract
Deletion of UBE3A causes the neurodevelopmental disorder Angelman syndrome (AS), while duplication or triplication of UBE3A is linked to autism. These genetic findings suggest that the ubiquitin ligase activity of UBE3A must be tightly maintained to promote normal brain development. Here, we found that protein kinase A (PKA) phosphorylates UBE3A in a region outside of the catalytic domain at residue T485 and inhibits UBE3A activity toward itself and other substrates. A de novo autism-linked missense mutation disrupts this phosphorylation site, causing enhanced UBE3A activity in vitro, enhanced substrate turnover in patient-derived cells, and excessive dendritic spine development in the brain. Our study identifies PKA as an upstream regulator of UBE3A activity and shows that an autism-linked mutation disrupts this phosphorylation control. Moreover, our findings implicate excessive UBE3A activity and the resulting synaptic dysfunction to autism pathogenesis.
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Affiliation(s)
- Jason J Yi
- Department of Cell Biology and Physiology and UNC Neuroscience Center, The University of North Carolina, Chapel Hill, NC 27599, USA; Department of Pharmacology, The University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Janet Berrios
- Department of Cell Biology and Physiology and UNC Neuroscience Center, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jason M Newbern
- School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA
| | - William D Snider
- Department of Cell Biology and Physiology and UNC Neuroscience Center, The University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Benjamin D Philpot
- Department of Cell Biology and Physiology and UNC Neuroscience Center, The University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Klaus M Hahn
- Department of Pharmacology, The University of North Carolina, Chapel Hill, NC 27599, USA
| | - Mark J Zylka
- Department of Cell Biology and Physiology and UNC Neuroscience Center, The University of North Carolina, Chapel Hill, NC 27599, USA; Carolina Institute for Developmental Disabilities, The University of North Carolina, Chapel Hill, NC 27599, USA.
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10
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Sadikovic B, Fernandes P, Zhang VW, Ward PA, Miloslavskaya I, Rhead W, Rosenbaum R, Gin R, Roa B, Fang P. Mutation Update for UBE3A variants in Angelman syndrome. Hum Mutat 2015; 35:1407-17. [PMID: 25212744 DOI: 10.1002/humu.22687] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 08/25/2014] [Indexed: 11/07/2022]
Abstract
Angelman syndrome is a neurodevelopmental disorder caused by a deficiency of the imprinted and maternally expressed UBE3A gene. Although de novo genetic and epigenetic imprinting defects of UBE3A genomic locus account for majority of Angelman diagnoses, approximately 10% of individuals affected with Angelman syndrome are a result of UBE3A loss-of-function mutations occurring on the expressed maternal chromosome. The variants described in this manuscript represent the analysis of 2,515 patients referred for UBE3A gene sequencing at our institution, along with a comprehensive review of the UBE3A mutation literature. Of these, 267 (10.62%) patients had a report issued for detection of a UBE3A gene nucleotide variant, which in many cases involved family studies resulting in reclassification of variants of unknown clinical significance (VUS). Overall, 111 (4.41%) probands had a nucleotide change classified as pathogenic or strongly favored to be pathogenic, 29 (1.15%) had a VUS, and 126 (5.0%) had a nucleotide change classified as benign or strongly favored to be benign. All variants and their clinical interpretations are submitted to NCBI ClinVar, a freely accessible human variation and phenotype database.
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Affiliation(s)
- Bekim Sadikovic
- Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada
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11
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Carvill GL, Heavin SB, Yendle SC, McMahon JM, O’Roak BJ, Cook J, Khan A, Dorschner MO, Weaver M, Calvert S, Malone S, Wallace G, Stanley T, Bye AME, Bleasel A, Howell KB, Kivity S, Mackay MT, Rodriguez-Casero V, Webster R, Korczyn A, Afawi Z, Zelnick N, Lerman-Sagie T, Lev D, Møller RS, Gill D, Andrade DM, Freeman JL, Sadleir LG, Shendure J, Berkovic SF, Scheffer IE, Mefford HC. Targeted resequencing in epileptic encephalopathies identifies de novo mutations in CHD2 and SYNGAP1. Nat Genet 2013; 45:825-30. [PMID: 23708187 PMCID: PMC3704157 DOI: 10.1038/ng.2646] [Citation(s) in RCA: 467] [Impact Index Per Article: 42.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Accepted: 05/01/2013] [Indexed: 12/16/2022]
Abstract
Epileptic encephalopathies are a devastating group of epilepsies with poor prognosis, of which the majority are of unknown etiology. We perform targeted massively parallel resequencing of 19 known and 46 candidate genes for epileptic encephalopathy in 500 affected individuals (cases) to identify new genes involved and to investigate the phenotypic spectrum associated with mutations in known genes. Overall, we identified pathogenic mutations in 10% of our cohort. Six of the 46 candidate genes had 1 or more pathogenic variants, collectively accounting for 3% of our cohort. We show that de novo CHD2 and SYNGAP1 mutations are new causes of epileptic encephalopathies, accounting for 1.2% and 1% of cases, respectively. We also expand the phenotypic spectra explained by SCN1A, SCN2A and SCN8A mutations. To our knowledge, this is the largest cohort of cases with epileptic encephalopathies to undergo targeted resequencing. Implementation of this rapid and efficient method will change diagnosis and understanding of the molecular etiologies of these disorders.
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Affiliation(s)
- Gemma L. Carvill
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
| | - Sinéad B. Heavin
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Simone C. Yendle
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Jacinta M. McMahon
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Brian J. O’Roak
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98195, USA
| | - Joseph Cook
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
| | - Adiba Khan
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
| | - Michael O Dorschner
- Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, Washington, 98195, USA
- Veteran Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Molly Weaver
- Department of Psychiatry & Behavioral Sciences, University of Washington, Seattle, Washington, 98195, USA
- Veteran Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Sophie Calvert
- Neurosciences Children’s Health Queensland, Royal and Mater Children’s Hospitals, Brisbane, Queensland, Australia
| | - Stephen Malone
- Neurosciences Children’s Health Queensland, Royal and Mater Children’s Hospitals, Brisbane, Queensland, Australia
| | - Geoffrey Wallace
- Neurosciences Children’s Health Queensland, Royal and Mater Children’s Hospitals, Brisbane, Queensland, Australia
| | - Thorsten Stanley
- Department of Paediatrics, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
| | - Ann M. E. Bye
- Department of Paediatric Neurology, University of New South Wales, Sydney Children’s Hospital, Sydney, New South Wales, Australia
| | - Andrew Bleasel
- Westmead Hospital, University of Sydney, Sydney, New South Wales, Australia
| | - Katherine B. Howell
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
| | - Sara Kivity
- Epilepsy Unit, Schneider Children’s Medical Center of Israel, Petach Tikvah, Israel
| | - Mark T. Mackay
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
- Critical Care & Neurosciences Theme, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, The Royal Children’s Hospital, Melbourne, Victoria, Australia
| | | | - Richard Webster
- TY Nelson Department of Neurology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Amos Korczyn
- Department of Neurology, Tel-Aviv University, Tel-Aviv, Israel
| | - Zaid Afawi
- Tel-Aviv University Medical School, Tel-Aviv, Israel
| | - Nathanel Zelnick
- Department of Pediatrics, Carmel Medical Center, Technion Faculty of Medicine, Haifa, Israel
| | - Tally Lerman-Sagie
- Metabolic-Neurogenetic Service, Wolfson Medical Center, Holon, and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - Dorit Lev
- Metabolic-Neurogenetic Service, Wolfson Medical Center, Holon, and Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | | | - Deepak Gill
- TY Nelson Department of Neurology, The Children's Hospital at Westmead, Sydney, New South Wales, Australia
| | - Danielle M. Andrade
- Division of Neurology, Department of Medicine, University of Toronto, Toronto Western Hospital, Krembil Neurosciences Program. Toronto, Canada
| | - Jeremy L. Freeman
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
- Critical Care & Neurosciences Theme, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Lynette G. Sadleir
- Department of Paediatrics, School of Medicine and Health Sciences, University of Otago, Wellington, New Zealand
| | - Jay Shendure
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98195, USA
| | - Samuel F. Berkovic
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
| | - Ingrid E. Scheffer
- Epilepsy Research Centre, Department of Medicine, University of Melbourne, Austin Health, Melbourne, Victoria, Australia
- Department of Neurology, The Royal Children’s Hospital, Parkville, Melbourne, Victoria, Australia
- Department of Paediatrics, The University of Melbourne, The Royal Children’s Hospital, Melbourne, Victoria, Australia
- Florey Institute, Melbourne, Victoria, Australia
| | - Heather C. Mefford
- Division of Genetic Medicine, Department of Pediatrics, University of Washington, Seattle, Washington, 98195, USA
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12
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Tzagkaraki E, Sofocleous C, Fryssira-Kanioura H, Dinopoulos A, Goulielmos G, Mavrou A, Kitsiou-Tzeli S, Kanavakis E, Sofia KT, Kanavakis E. Screening of UBE3A gene in patients referred for Angelman Syndrome. Eur J Paediatr Neurol 2013; 17:366-73. [PMID: 23416059 DOI: 10.1016/j.ejpn.2012.12.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 12/27/2012] [Accepted: 12/30/2012] [Indexed: 01/05/2023]
Abstract
Angelman Syndrome (AS) is a neurodevelopmental disorder characterized by severe developmental delay, speech impairment and unique behaviors including inappropriate laughter and happy disposition. AS is related to deficient maternal UBE3A gene expression caused either by chromosomal deletions, uniparental disomy, molecular defects of the imprinted 15q11-q13 critical region or by loss of function mutations in the maternally inherited UBE3A. In the present study, screening UBE3A was performed in 43 patients who were referred for AS but whom previous molecular diagnostic tests failed to provide a diagnosis. Two causative mutations--one of them novel--and four polymorphic variants one of which is also novel were revealed. Further investigation of 7 patients disclosed defects in other genes involved in clinical phenotypes mimicking AS. A typical EEG pattern and microcephaly in patients with developmental delay prompt for AS investigation while wide genetic screening should be applied to help resolution of the complex phenotypes characterized by developmental delay.
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Affiliation(s)
- Evmorfia Tzagkaraki
- Department of Medical Genetics, University of Athens School of Medicine, Choremeio Research Laboratory, Aghia Sophia Children's Hospital, Thivon and Levadeias str, 11527 Goudi, Athens, Greece.
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13
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Knezevic T, Petronic I, Nikolic D, Cirovic D, Krstic V, Ducic S, Konstantinovic L, Foti C. Evaluation of visual evoked potentials in patient with angelmans syndrome - case report. Balkan Med J 2013; 30:242-3. [PMID: 25207107 DOI: 10.5152/balkanmedj.2013.8280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 01/08/2013] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND Angelman syndrome (AS) is a genetic disorder with varying degrees of neurological impairment. It is often associated with ocular involvement. CASE REPORT We present a child diagnosed with AS who had a deletion on the short arm of chromosome 15. The child seemed to be happy, with developmental delay, speech problem, and altering strabismus. To assess the potential presence and degree of damage in the visual pathway, we recorded monocular flash visual evoked potentials (VEPs). Our results revealed the presence of severe central afferent dysfunction in both optical pathways. CONCLUSION VEPs can be used in patients with AS and visual disturbances to assess the integrity of the visual system.
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Affiliation(s)
- Tatjana Knezevic
- Physical Medicine and Rehabilitation, University Childrens Hospital, Belgrade, Serbia
| | - Ivana Petronic
- University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Dejan Nikolic
- Physical Medicine and Rehabilitation, University Childrens Hospital, Belgrade, Serbia
| | - Dragana Cirovic
- University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Vera Krstic
- University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | - Sinisa Ducic
- University of Belgrade, Faculty of Medicine, Belgrade, Serbia
| | | | - Calogero Foti
- Physical and Rehabilitation Medicine, Tor Vergata University, Rome, Italy
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14
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Dagli A, Buiting K, Williams CA. Molecular and Clinical Aspects of Angelman Syndrome. Mol Syndromol 2011; 2:100-112. [PMID: 22670133 DOI: 10.1159/000328837] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The Angelman syndrome is caused by disruption of the UBE3A gene and is clinically delineated by the combination of severe mental disability, seizures, absent speech, hypermotoric and ataxic movements, and certain remarkable behaviors. Those with the syndrome have a predisposition toward apparent happiness and paroxysms of laughter, and this finding helps distinguish Angelman syndrome from other conditions involving severe developmental handicap. Accurate diagnosis rests on a combination of clinical criteria and molecular and/or cytogenetic testing. Analysis of parent-specific DNA methylation imprints in the critical 15q11.2-q13 genomic region identifies 75-80% of all individuals with the syndrome, including those with cytogenetic deletions, imprinting center defects and paternal uniparental disomy. In the remaining group, UBE3A sequence analysis identifies an additional percentage of patients, but 5-10% will remain who appear to have the major clinical phenotypic features but do not have any identifiable genetic abnormalities. Genetic counseling for recurrence risk is complicated because multiple genetic mechanisms can disrupt the UBE3A gene, and there is also a unique inheritance pattern associated with UBE3A imprinting. Angelman syndrome is a prototypical developmental syndrome due to its remarkable behavioral phenotype and because UBE3A is so crucial to normal synaptic function and neural plasticity.
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Affiliation(s)
- A Dagli
- Raymond C. Philips Unit, Division of Genetics and Metabolism, Department of Pediatrics, University of Florida, Gainesville, Fla., USA
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15
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Spontaneous seizures and altered gene expression in GABA signaling pathways in a mind bomb mutant zebrafish. J Neurosci 2010; 30:13718-28. [PMID: 20943912 DOI: 10.1523/jneurosci.1887-10.2010] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Disruption of E3 ubiquitin ligase activity in immature zebrafish mind bomb mutants leads to a failure in Notch signaling, excessive numbers of neurons, and depletion of neural progenitor cells. This neurogenic phenotype is associated with defects in neural patterning and brain development. Because developmental brain abnormalities are recognized as an important feature of childhood neurological disorders such as epilepsy and autism, we determined whether zebrafish mutants with grossly abnormal brain structure exhibit spontaneous electrical activity that resembles the long-duration, high-amplitude multispike discharges reported in immature zebrafish exposed to convulsant drugs. Electrophysiological recordings from agar immobilized mind bomb mutants at 3 d postfertilization confirmed the occurrence of electrographic seizure activity; seizure-like behaviors were also noted during locomotion video tracking of freely behaving mutants. To identify genes differentially expressed in the mind bomb mutant and provide insight into molecular pathways that may mediate these epileptic phenotypes, a transcriptome analysis was performed using microarray. Interesting candidate genes were further analyzed using conventional reverse transcriptase-PCR and real-time quantitative PCR, as well as whole-mount in situ hybridization. Approximately 150 genes, some implicated in development, transcription, cell metabolism, and signal transduction, are differentially regulated, including downregulation of several genes necessary for GABA-mediated signaling. These findings identify a collection of gene transcripts that may be responsible for the abnormal electrical discharge and epileptic activities observed in a mind bomb zebrafish mutant. This work may have important implications for neurological and neurodevelopmental disorders associated with mutations in ubiquitin ligase activity.
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16
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Abaied L, Trabelsi M, Chaabouni M, Kharrat M, Kraoua L, M'rad R, Tebib N, Maazoul F, Chaabouni H. A novel UBE3A truncating mutation in large Tunisian Angelman syndrome pedigree. Am J Med Genet A 2010; 152A:141-6. [PMID: 20034088 DOI: 10.1002/ajmg.a.33179] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
We identified in a large Tunisian pedigree a novel UBE3A frameshift mutation in exon 16 coding region, and we expect that the resulting UBE3A truncated protein in our patients is non-functional since the mutation implies the catalytic region of the enzyme. The family includes 14 affected patients born from four sisters. This mutation was found in all surviving affected individuals and their mothers pointing out the importance of genetic counseling possibility in Angelman syndrome (AS). All patients had severe mental retardation with epilepsy and microcephaly. Minor clinical expression variation was observed among the investigated patients. The severity of clinical expression is related to the detected molecular variation: deletion of 15 bp and insertion of 7 bp. These results are concordant with the gene expression observed in previously reported individuals with AS and truncated UBE3A protein.
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Affiliation(s)
- L Abaied
- Faculté de Médecine de Tunis, Laboratoire de Génétique Humaine, Tunis, Tunisia
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