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Engal E, Oja KT, Maroofian R, Geminder O, Le TL, Marzin P, Guimier A, Mor E, Zvi N, Elefant N, Zaki MS, Gleeson JG, Muru K, Pajusalu S, Wojcik MH, Pachat D, Elmaksoud MA, Chan Jeong W, Lee H, Bauer P, Zifarelli G, Houlden H, Daana M, Elpeleg O, Amiel J, Lyonnet S, Gordon CT, Harel T, Õunap K, Salton M, Mor-Shaked H. Bi-allelic loss-of-function variants in WBP4, encoding a spliceosome protein, result in a variable neurodevelopmental syndrome. Am J Hum Genet 2023; 110:2112-2119. [PMID: 37963460 PMCID: PMC10716347 DOI: 10.1016/j.ajhg.2023.10.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 10/25/2023] [Accepted: 10/25/2023] [Indexed: 11/16/2023] Open
Abstract
Over two dozen spliceosome proteins are involved in human diseases, also referred to as spliceosomopathies. WW domain-binding protein 4 (WBP4) is part of the early spliceosomal complex and has not been previously associated with human pathologies in the Online Mendelian Inheritance in Man (OMIM) database. Through GeneMatcher, we identified ten individuals from eight families with a severe neurodevelopmental syndrome featuring variable manifestations. Clinical manifestations included hypotonia, global developmental delay, severe intellectual disability, brain abnormalities, musculoskeletal, and gastrointestinal abnormalities. Genetic analysis revealed five different homozygous loss-of-function variants in WBP4. Immunoblotting on fibroblasts from two affected individuals with different genetic variants demonstrated a complete loss of protein, and RNA sequencing analysis uncovered shared abnormal splicing patterns, including in genes associated with abnormalities of the nervous system, potentially underlying the phenotypes of the probands. We conclude that bi-allelic variants in WBP4 cause a developmental disorder with variable presentations, adding to the growing list of human spliceosomopathies.
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Affiliation(s)
- Eden Engal
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; Department of Military Medicine and "Tzameret," Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Kaisa Teele Oja
- Genetics and Personalized Medicine Clinic, Tartu University Hospital, Tartu, Estonia; Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Reza Maroofian
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Ophir Geminder
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel; Department of Military Medicine and "Tzameret," Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Thuy-Linh Le
- Laboratory of Embryology and Genetics of Human Malformations, Institut National de La Santé et de La Recherche Médicale (INSERM) UMR 1163, Institut Imagine and Université Paris Cité, 75015 Paris, France
| | - Pauline Marzin
- Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, AP-HP, 75015 Paris, France
| | - Anne Guimier
- Laboratory of Embryology and Genetics of Human Malformations, Institut National de La Santé et de La Recherche Médicale (INSERM) UMR 1163, Institut Imagine and Université Paris Cité, 75015 Paris, France; Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, AP-HP, 75015 Paris, France
| | - Evyatar Mor
- Department of Computer Science, Ben-Gurion University of the Negev, Beersheba, Israel
| | - Naama Zvi
- Department of Genetics, Hadassah Medical Organization, Jerusalem, Israel
| | - Naama Elefant
- Department of Genetics, Hadassah Medical Organization, Jerusalem, Israel
| | - Maha S Zaki
- Department of Clinical Genetics, Human Genetics and Genome Research Institute, Cairo, Egypt
| | - Joseph G Gleeson
- Department of Neurosciences, University of California, San Diego, La Jolla, USA; Rady Children's Institute for Genomic Medicine, San Diego, La Jolla, USA
| | - Kai Muru
- Genetics and Personalized Medicine Clinic, Tartu University Hospital, Tartu, Estonia; Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Sander Pajusalu
- Genetics and Personalized Medicine Clinic, Tartu University Hospital, Tartu, Estonia; Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | | | - Divya Pachat
- Department of Medical Genetics, Aster MIMS (Malabar Institute of Medical Sciences)-Calicut, Kerala, India
| | - Marwa Abd Elmaksoud
- Neurology Unit, Department of Pediatrics, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | | | | | - Peter Bauer
- CENTOGENE GmbH, Am Strande 7, 18055 Rostock, Germany
| | | | - Henry Houlden
- Department of Neuromuscular Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Muhannad Daana
- Child Development Centers, Clalit Health Care Services, Jerusalem, Israel
| | - Orly Elpeleg
- Department of Genetics, Hadassah Medical Organization, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Jeanne Amiel
- Laboratory of Embryology and Genetics of Human Malformations, Institut National de La Santé et de La Recherche Médicale (INSERM) UMR 1163, Institut Imagine and Université Paris Cité, 75015 Paris, France; Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, AP-HP, 75015 Paris, France
| | - Stanislas Lyonnet
- Laboratory of Embryology and Genetics of Human Malformations, Institut National de La Santé et de La Recherche Médicale (INSERM) UMR 1163, Institut Imagine and Université Paris Cité, 75015 Paris, France; Service de Médecine Génomique des Maladies Rares, Hôpital Necker-Enfants Malades, AP-HP, 75015 Paris, France
| | - Christopher T Gordon
- Laboratory of Embryology and Genetics of Human Malformations, Institut National de La Santé et de La Recherche Médicale (INSERM) UMR 1163, Institut Imagine and Université Paris Cité, 75015 Paris, France
| | - Tamar Harel
- Department of Genetics, Hadassah Medical Organization, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Katrin Õunap
- Genetics and Personalized Medicine Clinic, Tartu University Hospital, Tartu, Estonia; Institute of Clinical Medicine, University of Tartu, Tartu, Estonia
| | - Maayan Salton
- Department of Biochemistry and Molecular Biology, The Institute for Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 9112102, Israel
| | - Hagar Mor-Shaked
- Department of Genetics, Hadassah Medical Organization, Jerusalem, Israel; Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
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Pinto C, Guerra J, Pinheiro M, Escudeiro C, Santos C, Pinto P, Porto M, Bartosch C, Silva J, Peixoto A, Teixeira MR. Combined germline and tumor mutation signature testing identifies new families with NTHL1 tumor syndrome. Front Genet 2023; 14:1254908. [PMID: 37727376 PMCID: PMC10505957 DOI: 10.3389/fgene.2023.1254908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Accepted: 08/14/2023] [Indexed: 09/21/2023] Open
Abstract
NTHL1 tumor syndrome is an autosomal recessive rare disease caused by biallelic inactivating variants in the NTHL1 gene and which presents a broad tumor spectrum. To contribute to the characterization of the phenotype of this syndrome, we studied 467 index patients by KASP assay or next-generation sequencing, including 228 patients with colorectal polyposis and 239 patients with familial/personal history of multiple tumors (excluding multiple breast/ovarian/polyposis). Three NTHL1 tumor syndrome families were identified in the group of patients with polyposis and none in patients with familial/personal history of multiple tumors. Altogether, we identified nine affected patients with polyposis (two of them diagnosed after initiating colorectal cancer surveillance) with biallelic pathogenic or likely pathogenic NTHL1 variants, as well as two index patients with one pathogenic or likely pathogenic NTHL1 variant in concomitance with a missense variant of uncertain significance. Here we identified a novel inframe deletion classified as likely pathogenic using the ACMG criteria, supported also by tumor mutational signature analysis. Our findings indicate that the NTHL1 tumor syndrome is a multi-tumor syndrome strongly associated with polyposis and not with multiple tumors without polyposis.
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Affiliation(s)
- Carla Pinto
- Department of Laboratory Genetics, Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Department of Pathological, Cytological and Thanatological Anatomy, School of Health, Polytechnic Institute of Porto, Porto, Portugal
| | - Joana Guerra
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Doctoral Programme in Biomedical Sciences, School of Medicine and Biomedical Sciences (ICBAS), University of Porto, Porto, Portugal
| | - Manuela Pinheiro
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - Carla Escudeiro
- Department of Laboratory Genetics, Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - Catarina Santos
- Department of Laboratory Genetics, Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - Pedro Pinto
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - Miguel Porto
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - Carla Bartosch
- Department of Pathology, Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Cancer Biology and Epigenetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - João Silva
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Department of Medical Genetics, Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - Ana Peixoto
- Department of Laboratory Genetics, Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
| | - Manuel R. Teixeira
- Department of Laboratory Genetics, Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- Cancer Genetics Group, IPO-Porto Research Center (CI-IPOP)/RISE@CI-IPOP (Health Research Network), Portuguese Oncology Institute of Porto (IPO-Porto)/Porto Comprehensive Cancer Center, Porto, Portugal
- School of Medicine and Biomedical Sciences (ICBAS), University of Porto, Porto, Portugal
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Correia-Costa GR, de Leeuw N, Pfundt R, Sgardioli IC, Dos Santos AP, de Lima Santos M, Gil-da-Silva-Lopes VL, Vieira TP. Biallelic frameshift variant in the TBC1D2B gene in two siblings with progressive gingival overgrowth, fibrous dysplasia of face, and mental deterioration. Clin Genet 2022; 102:537-542. [PMID: 36029130 DOI: 10.1111/cge.14215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 01/27/2023]
Abstract
Biallelic loss-of-function variants in the TBC1D2B gene were recently reported as a cause of a neurodevelopmental disorder with seizures and gingival overgrowth. Here, we report two male siblings with the similar clinical characteristics. They started with gingival overgrowth and bilateral growth of soft tissues in the malar region at 3 years of age, which evolved with significant maxillary hypertrophy and compression of the brainstem due to fibrous dysplasia of facial bones. After disease evolution, they presented with mental deterioration, limb tremors, and gait ataxia. One of them also presented with seizures. Whole exome sequencing revealed a novel biallelic frameshift variant [c.595del; p.(Val199Trpfs*22)] in the TBC1D2B gene in both patients, which was confirmed and found in heterozygous state in each of their parents. There are strong similarities in clinical characteristics, age of onset, and evolution between the patients described here and cases reported in the literature, including cherubism-like phenotype with progressive gingival overgrowth and seizures. This is the fourth family in the world in which a biallelic loss-of-function variant in the TBC1D2B gene is associated with this phenotype. These results support that loss of TBC1D2B is the cause of this rare condition.
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Affiliation(s)
- Gabriela Roldão Correia-Costa
- Department of Translational Medicine - Laboratory of Human Cytogenetics and Cytogenomics, School of Medical Sciences, State University of Campinas, São Paulo, Brazil
| | - Nicole de Leeuw
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Rolph Pfundt
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Ilária Cristina Sgardioli
- Department of Translational Medicine - Laboratory of Human Cytogenetics and Cytogenomics, School of Medical Sciences, State University of Campinas, São Paulo, Brazil
| | - Ana Paula Dos Santos
- Department of Translational Medicine - Laboratory of Human Cytogenetics and Cytogenomics, School of Medical Sciences, State University of Campinas, São Paulo, Brazil
| | - Marilza de Lima Santos
- Department of Translational Medicine - Laboratory of Human Cytogenetics and Cytogenomics, School of Medical Sciences, State University of Campinas, São Paulo, Brazil
| | - Vera Lúcia Gil-da-Silva-Lopes
- Department of Translational Medicine - Laboratory of Human Cytogenetics and Cytogenomics, School of Medical Sciences, State University of Campinas, São Paulo, Brazil
| | - Társis Paiva Vieira
- Department of Translational Medicine - Laboratory of Human Cytogenetics and Cytogenomics, School of Medical Sciences, State University of Campinas, São Paulo, Brazil
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Hegele RA. APOC3 Interference for Familial Chylomicronaemia Syndrome. touchREV Endocrinol 2022; 18:82-83. [PMID: 36694895 PMCID: PMC9835816 DOI: 10.17925/ee.2022.18.2.82] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Accepted: 09/13/2022] [Indexed: 12/13/2022]
Abstract
Patients with familial chylomicronaemia syndrome (FCS) have severe hypertriglyceridaemia due to genetically absent lipolytic capacity. They have a poor response to conventional therapies. To reduce the risk of potentially fatal pancreatitis, the management of FCS relies principally on a strict low-fat diet, which is difficult to follow and compromises quality of life. Targeted reduction of apolipoprotein C-III using new anti-APOC3 agents, such as the short interfering RNA ARO-APOC3, represents a promising approach to correct the severe biochemical disturbance in FCS.
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Affiliation(s)
- Robert A Hegele
- Departments of Medicine, (Division of Endocrinology) and Biochemistry, Western University, London, Canada
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Charnay T, Mougel G, Amouroux C, Gueorguieva I, Joubert F, Pertuit M, Reynaud R, Barlier A, Brue T, Saveanu A. A novel TBX19 gene mutation in patients with isolated ACTH deficiency from distinct families with a common geographical origin. Front Endocrinol (Lausanne) 2022; 13:1080649. [PMID: 36890856 PMCID: PMC9987334 DOI: 10.3389/fendo.2022.1080649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/28/2022] [Indexed: 02/22/2023] Open
Abstract
Isolated ACTH deficiency (IAD) is a life-threatening condition, particularly in the neonatal period, while a main consequence of undiagnosed isolated ACTH deficiency in survivors is cognitive impairment. TBX19 is involved in the differentiation and proliferation of corticotropic cells and TBX19 mutations are responsible for more than 60% of neonatal cases of IAD. We describe a new variant of the main TBX19 transcript (NM 005149.3, c.840del (p.(Glu280Asp fs*27)), classified as pathogenic, whose pathogenicity is assumed to be due to nonsense mediated decay leading to non-expression of T-box transcription factor TBX19. Moreover we summarize the TBX19 mutations published as individual cases since our last large cohort. Interestingly, this pathogenic variant was identified in four patients from three apparently unrelated families. Two of these families were consanguineous, and after investigations all of three were discovered to have roots in the same mountainous region of northern Morocco, suggesting a founder effect. Early diagnosis, timely treatment (hydrocortisone therapy) and preventive education allowed normal development, growth and quality of life in all patients.
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Affiliation(s)
- Théo Charnay
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1251, Marseille Medical Genetics (MMG), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
- Laboratory of Molecular Biology, Centre Hospitalier Universitaire Conception, Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
| | - Gregory Mougel
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1251, Marseille Medical Genetics (MMG), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
- Laboratory of Molecular Biology, Centre Hospitalier Universitaire Conception, Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
| | - Cyril Amouroux
- Paediatric Department, Endocrinology Unit, Arnaud de Villeneuve Hospital, Montpellier University Hospital, Montpellier, France
| | - Iva Gueorguieva
- Paediatric Department, Endocrinology Unit, Children’s Center, Jeanne-de-Flandre Hospital, Lille University Hospital, Lille, France
| | - Florence Joubert
- Department of Pediatrics, Centre Hospitalier d’Avignon, Avignon, France
| | - Morgane Pertuit
- Laboratory of Molecular Biology, Centre Hospitalier Universitaire Conception, Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
| | - Rachel Reynaud
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1251, Marseille Medical Genetics (MMG), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
- Department of Multidisciplinary Peadiatrics, Centre de Référence des Maladies Rares d’origine hypophysaire HYPO, Hôpital Timone-Enfants, Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
| | - Anne Barlier
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1251, Marseille Medical Genetics (MMG), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
- Laboratory of Molecular Biology, Centre Hospitalier Universitaire Conception, Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
| | - Thierry Brue
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1251, Marseille Medical Genetics (MMG), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
- Department of Endocrinology, Centre de Référence des Maladies Rares de l’hypophyse HYPO, Hôpital de la Conception, Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
| | - Alexandru Saveanu
- Institut National de la Santé et de la Recherche Médicale (INSERM) U1251, Marseille Medical Genetics (MMG), Institut Marseille Maladies Rares (MarMaRa), Aix-Marseille Université, Marseille, France
- Laboratory of Molecular Biology, Centre Hospitalier Universitaire Conception, Assistance Publique-Hôpitaux de Marseille (AP-HM), Marseille, France
- *Correspondence: Alexandru Saveanu,
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Samanta D, Arya K. Electroclinical Findings of SYNJ1 Epileptic Encephalopathy. J Pediatr Neurosci 2020; 15:29-33. [PMID: 32435303 PMCID: PMC7227754 DOI: 10.4103/jpn.jpn_10_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 06/10/2019] [Accepted: 11/18/2019] [Indexed: 01/03/2023] Open
Abstract
Introduction Early-onset epileptic encephalopathies are among the most severe early-onset epilepsies, leading to progressive neurodegeneration. An increasing number of novel genetic causes continue to be uncovered as the primary etiology. Results We report a girl infant of Semitic (Saudi Arabian) descent who presented with multifocal seizures and later developed intractable infantile spasms and myoclonic seizures. Her clinical features and electroencephalography were consistent with early-onset epileptic encephalopathy. Whole exome sequence analysis showed homozygous novel pathogenic variant (variant p.Q287PfsX27; coding DNA c.858_862delACAAA) in the SYNJ1 gene. Conclusion This is a newly described early-onset epileptic encephalopathy secondary to a critical reduction of the dual phosphatase activity of SYNJ. Clinical features include early-onset intractable focal, myoclonic seizures, infantile spasms, and hypotonia progressing to spastic quadriparesis, opisthotonus, dystonia, profound developmental delay, and a progressive neurodegenerative course. Brain magnetic resonance imaging is usually normal. Electroencephalography shows diffuse slowing with multifocal epileptiform discharges or modified hypsarrhythmia. These findings further expand the clinical spectrum of synaptic dysregulation in patients with severe epilepsy and emphasize the importance of this biological pathway in seizure pathophysiology.
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Affiliation(s)
- Debopam Samanta
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR, USA
| | - Kapil Arya
- Child Neurology Section, Department of Pediatrics, University of Arkansas for Medical Sciences (UAMS), Little Rock, AR, USA
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Kimble DC, Lach FP, Gregg SQ, Donovan FX, Flynn EK, Kamat A, Young A, Vemulapalli M, Thomas JW, Mullikin JC, Auerbach AD, Smogorzewska A, Chandrasekharappa SC. A comprehensive approach to identification of pathogenic FANCA variants in Fanconi anemia patients and their families. Hum Mutat 2018; 39:237-254. [PMID: 29098742 PMCID: PMC5762269 DOI: 10.1002/humu.23366] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 10/20/2017] [Accepted: 10/22/2017] [Indexed: 11/11/2022]
Abstract
Fanconi anemia (FA) is a rare recessive DNA repair deficiency resulting from mutations in one of at least 22 genes. Two-thirds of FA families harbor mutations in FANCA. To genotype patients in the International Fanconi Anemia Registry (IFAR) we employed multiple methodologies, screening 216 families for FANCA mutations. We describe identification of 57 large deletions and 261 sequence variants, in 159 families. All but seven families harbored distinct combinations of two mutations demonstrating high heterogeneity. Pathogenicity of the 18 novel missense variants was analyzed functionally by determining the ability of the mutant cDNA to improve the survival of a FANCA-null cell line when treated with MMC. Overexpressed pathogenic missense variants were found to reside in the cytoplasm, and nonpathogenic in the nucleus. RNA analysis demonstrated that two variants (c.522G > C and c.1565A > G), predicted to encode missense variants, which were determined to be nonpathogenic by a functional assay, caused skipping of exons 5 and 16, respectively, and are most likely pathogenic. We report 48 novel FANCA sequence variants. Defining both variants in a large patient cohort is a major step toward cataloging all FANCA variants, and permitting studies of genotype-phenotype correlations.
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Affiliation(s)
- Danielle C Kimble
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Francis P Lach
- Laboratory of Genome Maintenance, The Rockefeller University, New York, New York
| | - Siobhan Q Gregg
- Laboratory of Genome Maintenance, The Rockefeller University, New York, New York
| | - Frank X Donovan
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Elizabeth K Flynn
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Aparna Kamat
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
| | - Alice Young
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - Meghana Vemulapalli
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - James W Thomas
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - James C Mullikin
- NIH Intramural Sequencing Center, National Human Genome Research Institute, Bethesda, Maryland
| | - Arleen D Auerbach
- Human Genetics and Hematology Program, The Rockefeller University, New York, New York
| | - Agata Smogorzewska
- Laboratory of Genome Maintenance, The Rockefeller University, New York, New York
| | - Settara C Chandrasekharappa
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, Bethesda, Maryland
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8
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Hardies K, Cai Y, Jardel C, Jansen AC, Cao M, May P, Djémié T, Hachon Le Camus C, Keymolen K, Deconinck T, Bhambhani V, Long C, Sajan SA, Helbig KL, Suls A, Balling R, Helbig I, De Jonghe P, Depienne C, De Camilli P, Weckhuysen S. Loss of SYNJ1 dual phosphatase activity leads to early onset refractory seizures and progressive neurological decline. Brain 2016; 139:2420-30. [PMID: 27435091 DOI: 10.1093/brain/aww180] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 06/07/2016] [Indexed: 12/30/2022] Open
Abstract
SYNJ1 encodes a polyphosphoinositide phosphatase, synaptojanin 1, which contains two consecutive phosphatase domains and plays a prominent role in synaptic vesicle dynamics. Autosomal recessive inherited variants in SYNJ1 have previously been associated with two different neurological diseases: a recurrent homozygous missense variant (p.Arg258Gln) that abolishes Sac1 phosphatase activity was identified in three independent families with early onset parkinsonism, whereas a homozygous nonsense variant (p.Arg136*) causing a severe decrease of mRNA transcript was found in a single patient with intractable epilepsy and tau pathology. We performed whole exome or genome sequencing in three independent sib pairs with early onset refractory seizures and progressive neurological decline, and identified novel segregating recessive SYNJ1 defects. A homozygous missense variant resulting in an amino acid substitution (p.Tyr888Cys) was found to impair, but not abolish, the dual phosphatase activity of SYNJ1, whereas three premature stop variants (homozygote p.Trp843* and compound heterozygote p.Gln647Argfs*6/p.Ser1122Thrfs*3) almost completely abolished mRNA transcript production. A genetic follow-up screening in a large cohort of 543 patients with a wide phenotypical range of epilepsies and intellectual disability revealed no additional pathogenic variants, showing that SYNJ1 deficiency is rare and probably linked to a specific phenotype. While variants leading to early onset parkinsonism selectively abolish Sac1 function, our results provide evidence that a critical reduction of the dual phosphatase activity of SYNJ1 underlies a severe disorder with neonatal refractory epilepsy and a neurodegenerative disease course. These findings further expand the clinical spectrum of synaptic dysregulation in patients with severe epilepsy, and emphasize the importance of this biological pathway in seizure pathophysiology.
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