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Seo G, Yu C, Han H, Xing L, Kattan RE, An J, Kizhedathu A, Yang B, Luo A, Buckle AL, Tifrea D, Edwards R, Huang L, Ju HQ, Wang W. The Hippo pathway noncanonically drives autophagy and cell survival in response to energy stress. Mol Cell 2023; 83:3155-3170.e8. [PMID: 37595580 PMCID: PMC10568779 DOI: 10.1016/j.molcel.2023.07.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 06/22/2023] [Accepted: 07/18/2023] [Indexed: 08/20/2023]
Abstract
The Hippo pathway is known for its crucial involvement in development, regeneration, organ size control, and cancer. While energy stress is known to activate the Hippo pathway and inhibit its effector YAP, the precise role of the Hippo pathway in energy stress response remains unclear. Here, we report a YAP-independent function of the Hippo pathway in facilitating autophagy and cell survival in response to energy stress, a process mediated by its upstream components MAP4K2 and STRIPAK. Mechanistically, energy stress disrupts the MAP4K2-STRIPAK association, leading to the activation of MAP4K2. Subsequently, MAP4K2 phosphorylates ATG8-family member LC3, thereby facilitating autophagic flux. MAP4K2 is highly expressed in head and neck cancer, and its mediated autophagy is required for head and neck tumor growth in mice. Altogether, our study unveils a noncanonical role of the Hippo pathway in energy stress response, shedding light on this key growth-related pathway in tissue homeostasis and cancer.
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Affiliation(s)
- Gayoung Seo
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Han Han
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Li Xing
- Irvine Materials Research Institute, University of California, Irvine, Irvine, CA 92697, USA
| | - Rebecca Elizabeth Kattan
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Jeongmin An
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Amrutha Kizhedathu
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Bing Yang
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Annabella Luo
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Abigail L Buckle
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA
| | - Delia Tifrea
- Department of Pathology, University of California, Irvine, Irvine, CA 92697, USA
| | - Robert Edwards
- Department of Pathology, University of California, Irvine, Irvine, CA 92697, USA
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697, USA
| | - Huai-Qiang Ju
- State Key Laboratory of Oncology in South China, Sun Yat-sen University Cancer Center, Guangzhou 510060, China.
| | - Wenqi Wang
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697, USA.
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2
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da Silva-Buttkus P, Spielmann N, Klein-Rodewald T, Schütt C, Aguilar-Pimentel A, Amarie OV, Becker L, Calzada-Wack J, Garrett L, Gerlini R, Kraiger M, Leuchtenberger S, Östereicher MA, Rathkolb B, Sanz-Moreno A, Stöger C, Hölter SM, Seisenberger C, Marschall S, Fuchs H, Gailus-Durner V, Hrabě de Angelis M. Knockout mouse models as a resource for the study of rare diseases. Mamm Genome 2023; 34:244-261. [PMID: 37160609 PMCID: PMC10290595 DOI: 10.1007/s00335-023-09986-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 03/07/2023] [Indexed: 05/11/2023]
Abstract
Rare diseases (RDs) are a challenge for medicine due to their heterogeneous clinical manifestations and low prevalence. There is a lack of specific treatments and only a few hundred of the approximately 7,000 RDs have an approved regime. Rapid technological development in genome sequencing enables the mass identification of potential candidates that in their mutated form could trigger diseases but are often not confirmed to be causal. Knockout (KO) mouse models are essential to understand the causality of genes by allowing highly standardized research into the pathogenesis of diseases. The German Mouse Clinic (GMC) is one of the pioneers in mouse research and successfully uses (preclinical) data obtained from single-gene KO mutants for research into monogenic RDs. As part of the International Mouse Phenotyping Consortium (IMPC) and INFRAFRONTIER, the pan-European consortium for modeling human diseases, the GMC expands these preclinical data toward global collaborative approaches with researchers, clinicians, and patient groups.Here, we highlight proprietary genes that when deleted mimic clinical phenotypes associated with known RD targets (Nacc1, Bach2, Klotho alpha). We focus on recognized RD genes with no pre-existing KO mouse models (Kansl1l, Acsf3, Pcdhgb2, Rabgap1, Cox7a2) which highlight novel phenotypes capable of optimizing clinical diagnosis. In addition, we present genes with intriguing phenotypic data (Zdhhc5, Wsb2) that are not presently associated with known human RDs.This report provides comprehensive evidence for genes that when deleted cause differences in the KO mouse across multiple organs, providing a huge translational potential for further understanding monogenic RDs and their clinical spectrum. Genetic KO studies in mice are valuable to further explore the underlying physiological mechanisms and their overall therapeutic potential.
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Affiliation(s)
- Patricia da Silva-Buttkus
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Nadine Spielmann
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Tanja Klein-Rodewald
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Christine Schütt
- Institute of Experimental Genetics, Applied Computational Biology, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Antonio Aguilar-Pimentel
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Oana V Amarie
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Lore Becker
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Julia Calzada-Wack
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Lillian Garrett
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Raffaele Gerlini
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Markus Kraiger
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Stefanie Leuchtenberger
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Manuela A Östereicher
- Institute of Experimental Genetics, Applied Computational Biology, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Birgit Rathkolb
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany
- Institute of Molecular Animal Breeding and Biotechnology, Gene Center, Ludwig-Maximilians-Universität München, Feodor-Lynen Strasse 25, 81377, Munich, Germany
| | - Adrián Sanz-Moreno
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Claudia Stöger
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Sabine M Hölter
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
- Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Claudia Seisenberger
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Susan Marschall
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Helmut Fuchs
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Valerie Gailus-Durner
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany
| | - Martin Hrabě de Angelis
- Institute of Experimental Genetics, German Mouse Clinic, Helmholtz Zentrum München, German Research Center for Environmental Health, Ingolstaedter Landstrasse 1, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Ingolstaedter Landstrasse 1, 85764, Neuherberg, Germany.
- Chair of Experimental Genetics, TUM School of Life Sciences, Technische Universität München, Alte Akademie 8, 85354, Freising, Germany.
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Geckinli B, Turkyilmaz A, Alavanda C, Sager G, Arslan Ates E, Soylemez MA, Arman A. Novel, homozygous RAB3GAP1 c.2606 + 1G>A, p.Glu830ValfsTer9 variant and chromosome 3q29 duplication in a Turkish individual with Warburg micro syndrome. Clin Dysmorphol 2023; 32:55-61. [PMID: 36876345 DOI: 10.1097/mcd.0000000000000454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Warburg micro syndrome (WARBM) is a rare, autosomal recessive, neurodevelopmental disorder characterized by microcephaly, cortical dysplasia, corpus callosum hypoplasia, congenital hypotonia leading to subsequent spastic quadriplegia, severe developmental delay and hypogenitalism. Ophthalmologic findings that may affect any ocular segment including characteristic, small, atonic pupils. WARBM is known to be caused by biallelic, pathogenic variants in at least five genes although additional genetic loci may exist. The RAB3GAP1 c.748 + 1G>A, p.Asp250CysfsTer24 founder variant has been described in families of Turkish ancestry. We report the clinical and molecular findings in three, unrelated, Turkish families with WARBM. A novel c.974-2A>G variant causing WARBM in three siblings of Turkish descent was found. Functional studies of the novel, c.2606 + 1G>A variant in patients' mRNA revealed skipping of exon 22 which results in a premature stop codon in exon 23. However, the clinical consequences of this variant are blended given that the individual also had a maternally inherited chromosome 3q29 microduplication.
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Affiliation(s)
- Bilge Geckinli
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul
| | - Ayberk Turkyilmaz
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul
- Department of Medical Genetics, Karadeniz Technical University School of Medicine, Trabzon
| | - Ceren Alavanda
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul
| | - Gunes Sager
- Department of Pediatric Neurology, Marmara University School of Medicine
- Pediatric Neurology, Kartal Dr. Lutfi Kirdar City Hospital
| | - Esra Arslan Ates
- Department of Medical Genetics, Marmara University Pendik Training and Research Hospital, Istanbul, Turkey
| | - Mehmet Ali Soylemez
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul
| | - Ahmet Arman
- Department of Medical Genetics, Marmara University School of Medicine, Istanbul
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4
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László ZI, Lele Z. Flying under the radar: CDH2 (N-cadherin), an important hub molecule in neurodevelopmental and neurodegenerative diseases. Front Neurosci 2022; 16:972059. [PMID: 36213737 PMCID: PMC9539934 DOI: 10.3389/fnins.2022.972059] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 08/31/2022] [Indexed: 12/03/2022] Open
Abstract
CDH2 belongs to the classic cadherin family of Ca2+-dependent cell adhesion molecules with a meticulously described dual role in cell adhesion and β-catenin signaling. During CNS development, CDH2 is involved in a wide range of processes including maintenance of neuroepithelial integrity, neural tube closure (neurulation), confinement of radial glia progenitor cells (RGPCs) to the ventricular zone and maintaining their proliferation-differentiation balance, postmitotic neural precursor migration, axon guidance, synaptic development and maintenance. In the past few years, direct and indirect evidence linked CDH2 to various neurological diseases, and in this review, we summarize recent developments regarding CDH2 function and its involvement in pathological alterations of the CNS.
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Affiliation(s)
- Zsófia I. László
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Budapest, Hungary
- Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, United Kingdom
| | - Zsolt Lele
- Momentum Laboratory of Molecular Neurobiology, Institute of Experimental Medicine, Budapest, Hungary
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5
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Kerkeni N, Kharrat M, Maazoul F, Boudabous H, M’rad R, Trabelsi M. Novel RAB3GAP1 Mutation in the First Tunisian Family With Warburg Micro Syndrome. J Clin Neurol 2022; 18:214-222. [PMID: 35196747 PMCID: PMC8926778 DOI: 10.3988/jcn.2022.18.2.214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/24/2021] [Accepted: 08/24/2021] [Indexed: 11/17/2022] Open
Affiliation(s)
- Nesrine Kerkeni
- University of Tunis El Manar, Faculty of Medicine of Tunis, Laboratory of Human Genetics LR99ES10, Tunis, Tunisia
| | - Maher Kharrat
- University of Tunis El Manar, Faculty of Medicine of Tunis, Laboratory of Human Genetics LR99ES10, Tunis, Tunisia
| | - Faouzi Maazoul
- University of Tunis El Manar, Faculty of Medicine of Tunis, Laboratory of Human Genetics LR99ES10, Tunis, Tunisia
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
| | - Hela Boudabous
- Department of Paediatrics, Rabta Hospital, Tunis, Tunisia
| | - Ridha M’rad
- University of Tunis El Manar, Faculty of Medicine of Tunis, Laboratory of Human Genetics LR99ES10, Tunis, Tunisia
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
| | - Mediha Trabelsi
- University of Tunis El Manar, Faculty of Medicine of Tunis, Laboratory of Human Genetics LR99ES10, Tunis, Tunisia
- Department of Congenital and Hereditary Diseases, Charles Nicolle Hospital, Tunis, Tunisia
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6
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Karamichos D, Escandon P, Vasini B, Nicholas SE, Van L, Dang DH, Cunningham RL, Riaz KM. Anterior pituitary, sex hormones, and keratoconus: Beyond traditional targets. Prog Retin Eye Res 2021; 88:101016. [PMID: 34740824 PMCID: PMC9058044 DOI: 10.1016/j.preteyeres.2021.101016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 12/13/2022]
Abstract
"The Diseases of the Horny-coat of The Eye", known today as keratoconus, is a progressive, multifactorial, non-inflammatory ectatic corneal disorder that is characterized by steepening (bulging) and thinning of the cornea, irregular astigmatism, myopia, and scarring that can cause devastating vision loss. The significant socioeconomic impact of the disease is immeasurable, as patients with keratoconus can have difficulties securing certain jobs or even joining the military. Despite the introduction of corneal crosslinking and improvements in scleral contact lens designs, corneal transplants remain the main surgical intervention for treating keratoconus refractory to medical therapy and visual rehabilitation. To-date, the etiology and pathogenesis of keratoconus remains unclear. Research studies have increased exponentially over the years, highlighting the clinical significance and international interest in this disease. Hormonal imbalances have been linked to keratoconus, both clinically and experimentally, with both sexes affected. However, it is unclear how (molecular/cellular signaling) or when (age/disease stage(s)) those hormones affect the keratoconic cornea. Previous studies have categorized the human cornea as an extragonadal tissue, showing modulation of the gonadotropins, specifically luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Studies herein provide new data (both in vitro and in vivo) to further delineate the role of hormones/gonadotropins in the keratoconus pathobiology, and propose the existence of a new axis named the Hypothalamic-Pituitary-Adrenal-Corneal (HPAC) axis.
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Affiliation(s)
- Dimitrios Karamichos
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA.
| | - Paulina Escandon
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Brenda Vasini
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Sarah E Nicholas
- North Texas Eye Research Institute, University of North Texas Health Science Center, 3430 Camp Bowie Blvd, Fort Worth, TX, 76107, USA; Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Lyly Van
- University of Oklahoma Health Sciences Center, 940 Stanton L Young, Oklahoma City, OK, USA; Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Deanna H Dang
- College of Medicine, University of Oklahoma Health Sciences Center, 940 Stanton L Young, Oklahoma City, OK, USA
| | - Rebecca L Cunningham
- Department of Pharmaceutical Sciences, University of North Texas Health Science Center, 3500 Camp Bowie Blvd, Fort Worth, TX, 76107, USA
| | - Kamran M Riaz
- Department of Ophthalmology, Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Two novel Warburg micro syndrome 1 cases caused by pathogenic variants in RAB3GAP1. Hum Genome Var 2021; 8:39. [PMID: 34702808 PMCID: PMC8548584 DOI: 10.1038/s41439-021-00171-9] [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: 03/31/2021] [Revised: 09/08/2021] [Accepted: 09/20/2021] [Indexed: 11/19/2022] Open
Abstract
In this study, we detected a novel pathogenic variant and a previously reported variant in RAB3GAP1 by whole-exome sequencing (NM_001172435.2: c.1552C>T, p.Gln518*; c.1471C>T, p.Arg491*). The first patient is a 3-year-old girl who presented with bilateral congenital cataracts, developmental delay, abnormal craniofacial features, drug-resistant constipation, and corpus callosum hypoplasia. The proband of the second family is a 13-year-old boy who suffers from developmental delay, quadriplegia, intellectual disability, abnormal craniofacial features, and corpus callosum hypoplasia.
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8
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Mutlu Albayrak H, Elçioğlu NH, Yeter B, Karaer K. From cataract to syndrome diagnosis: Revaluation of Warburg-Micro syndrome Type 1 patients. Am J Med Genet A 2021; 185:2325-2334. [PMID: 33951304 DOI: 10.1002/ajmg.a.62234] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 04/06/2021] [Accepted: 04/15/2021] [Indexed: 12/11/2022]
Abstract
Warburg-Micro syndrome (WARBM) is a rare autosomal recessively inherited neuro-ophthalmologic syndrome. Although WARBM shows genetic heterogeneity, the pathogenic variants in RAB3GAP1 were the most common cause of WARBM. In this study, we aimed to evaluate the detailed clinical and dysmorphic features of seven WARBM1 patients and overview the variant spectrum of RAB3GAP1 in comparison with the literature who were referred due to congenital cataracts. A previously reported homozygous variant (c.2187_2188delGAinsCT) was identified in three of these patients, while the other four had three novel variants (c.251_258delAGAA, c.2606+1G>A, and c.2861_2862dupGC). Congenital cataract and corpus callosum hypo/agenesia are pathognomonic for WARBM, which could be distinguished from other similar syndromes with additional typical dysmorphic facial features. Although there is no known phenotype and genotype correlation in any type of WARBM, RAB3GAP1 gene analysis should be previously requested as the first step of genetic diagnosis in clinically suspicious patients when it is not possible to request a multi-gene panel.
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Affiliation(s)
| | - Nursel H Elçioğlu
- Department of Pediatric Genetics, Marmara University, İstanbul, Turkey.,Faculty of Medicine, Eastern Mediterranean University, Mersin, Turkey
| | - Burcu Yeter
- Department of Pediatric Genetics, Marmara University, İstanbul, Turkey
| | - Kadri Karaer
- Department of Medical Genetics, Pamukkale University, Denizli, Turkey
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9
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Novel manifestations of Warburg micro syndrome type 1 caused by a new splicing variant of RAB3GAP1: a case report. BMC Neurol 2021; 21:180. [PMID: 33910511 PMCID: PMC8080372 DOI: 10.1186/s12883-021-02204-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 04/15/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The present study aimed to determine the underlying genetic factors causing the possible Warburg micro syndrome (WARBM) phenotype in two Iranian patients. CASE PRESENTATION A 5-year-old female and a 4.5-year-old male were referred due to microcephaly, global developmental delay, and dysmorphic features. After doing neuroimaging and clinical examinations, due to the heterogeneity of neurodevelopmental disorders, we subjected 7 family members to whole-exome sequencing. Three candidate variants were confirmed by Sanger sequencing and allele frequency of each variant was also determined in 300 healthy ethnically matched people using the tetra-primer amplification refractory mutation system-PCR and PCR-restriction fragment length polymorphism. To show the splicing effects, reverse transcription-PCR (RT-PCR) and RT-qPCR were performed, followed by Sanger sequencing. A novel homozygous variant-NM_012233.2: c.151-5 T > G; p.(Gly51IlefsTer15)-in the RAB3GAP1 gene was identified as the most likely disease-causing variant. RT-PCR/RT-qPCR showed that this variant can activate a cryptic site of splicing in intron 3, changing the splicing and gene expression processes. We also identified some novel manifestations in association with WARBM type 1 to touch upon abnormal philtrum, prominent antitragus, downturned corners of the mouth, malaligned teeth, scrotal hypoplasia, low anterior hairline, hypertrichosis of upper back, spastic diplegia to quadriplegia, and cerebral white matter signal changes. CONCLUSIONS Due to the common phenotypes between WARBMs and Martsolf syndrome (MIM: 212720), we suggest using the "RABopathies" term that can in turn cover a broad range of manifestations. This study can per se increase the genotype-phenotype spectrum of WARBM type 1.
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10
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Veerappa AM. Cascade of interactions between candidate genes reveals convergent mechanisms in keratoconus disease pathogenesis. Ophthalmic Genet 2021; 42:114-131. [PMID: 33554698 DOI: 10.1080/13816810.2020.1868013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Keratoconus is a progressive thinning, steepening and distortion of the cornea which can lead to loss of vision if left untreated. Keratoconus has a complex multifactorial etiology, with genetic and environmental components contributing to the disease pathophysiology. Studies have observed high concordance between monozygotic twins, discordance between dizygotic twins, and high familial segregation indicating the presence of a very strong genetic component in the pathogenesis of keratoconus. The use of genome-wide linkage studies on families and twins, genome-wide association studies (GWAS) on case-controls, next-generation sequencing (NGS)-based genomic screens on both familial and non-familial cohorts have led to the identification of keratoconus candidate genes with much greater success and increased resproducibility of genetic findings. This review focuses on candidate genes identified till date and attempts to understand their role in biological processes underlying keratoconus pathogenesis. In addition, using these genes I propose molecular pathways that could contribute to keratoconus pathogenesis. The pathways identified the presence of direct cross-talk between known candidate genes of keratoconus and remarkably, 28 known candidate genes have a direct relationship among themselves that involves direct protein-protein binding, regulatory activities such as activation and inhibition, chaperone, transcriptional activation/co-activation, and enzyme catalysis. This review attempts to describe these relationships and cross-talks in the context of keratoconus pathogenesis.
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Affiliation(s)
- Avinash M Veerappa
- Department of Ophthalmology, NYU Langone Medical Center, New York, New York, USA
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11
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Zhou D, Wang Q, Liu H. A novel mutation in RAB3GAP1 gene in Chinese patient causing the Warburg micro syndrome: A case report. Medicine (Baltimore) 2021; 100:e22902. [PMID: 33466118 PMCID: PMC7808449 DOI: 10.1097/md.0000000000022902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 09/25/2020] [Indexed: 01/05/2023] Open
Abstract
RATIONALE Warburg Micro syndrome is a rare, autosomal recessive disorder characterized by multiple organ abnormalities involving the ocular, nervous, and genital systems. This case report describes a novel mutation in the RAB3GAP1 gene associated with Warburg Micro syndrome. PATIENT CONCERNS A 6-month-old female infant with bilateral congenital cataracts and developmental delay was referred to our department for further assessment. She presented with facial dysmorphic features, including a prominent forehead, microphthalmia, wide nasal bridge, relatively narrow mouth, large anteverted ears, and micrognathia. DIAGNOSES The patient was diagnosed with Warburg Micro syndrome based on clinical manifestations, as well as a novel homozygous mutation in RAB3GAP1: c.75-2A>C. Both parents were identified as heterozygotic carriers of this mutation. INTERVENTIONS Bilateral cataract extraction and anterior vitrectomy were performed at age 6 months, followed by physical rehabilitation. Convex lenses were used to protect the eyes postoperatively until intraocular lens implantation. OUTCOMES Although the patient received physical rehabilitation, she suffered global developmental delay. LESSONS The c.75-2A>C mutation in RAB3GAP1 expands the spectrum of known mutations in this gene, and it may be associated with Warburg Micro syndrome. Genetic counselors may wish to take this finding into consideration, especially given the poor prognosis associated with the disease.
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Affiliation(s)
- Dan Zhou
- Department of Pediatrics, West China Second University Hospital, Sichuan University
- Key Laboratory of Birth Defects and Related Diseases in Women and Children, Sichuan University, Ministry of Education
| | - Qiu Wang
- Key Laboratory of Birth Defects and Related Diseases in Women and Children, Sichuan University, Ministry of Education
- Department of Rehabilitation Medicine, West China Second University Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Hanmin Liu
- Department of Pediatrics, West China Second University Hospital, Sichuan University
- Key Laboratory of Birth Defects and Related Diseases in Women and Children, Sichuan University, Ministry of Education
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Abdel‐Hamid MS, Abdel‐Ghafar SF, Ismail SR, Desouky LM, Issa MY, Effat LK, Zaki MS. Micro and Martsolf syndromes in 34 new patients: Refining the phenotypic spectrum and further molecular insights. Clin Genet 2020; 98:445-456. [DOI: 10.1111/cge.13825] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 07/26/2020] [Accepted: 07/28/2020] [Indexed: 11/28/2022]
Affiliation(s)
- Mohamed S. Abdel‐Hamid
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division National Research Centre Cairo Egypt
| | - Sherif F. Abdel‐Ghafar
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division National Research Centre Cairo Egypt
| | - Suzan R. Ismail
- Human Genetics Department, Medical Research Institute Alexandria University Egypt
| | - Lubna M. Desouky
- Human Genetics Department, Medical Research Institute Alexandria University Egypt
| | - Mahmoud Y. Issa
- Clinical Genetics Department, Human Genetics and Genome Research Division National Research Centre Cairo Egypt
| | - Laila K. Effat
- Medical Molecular Genetics Department, Human Genetics and Genome Research Division National Research Centre Cairo Egypt
| | - Maha S. Zaki
- Clinical Genetics Department, Human Genetics and Genome Research Division National Research Centre Cairo Egypt
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13
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Koparir A, Karatas OF, Yilmaz SS, Suer I, Ozer B, Yuceturk B, Ozen M. Revealing the functions of novel mutations in RAB3GAP1
in Martsolf and Warburg micro syndromes. Am J Med Genet A 2019; 179:579-587. [DOI: 10.1002/ajmg.a.61065] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/17/2019] [Accepted: 01/17/2019] [Indexed: 12/30/2022]
Affiliation(s)
- Asuman Koparir
- Department of Internal Medicine, Division of Medical Genetics; Istanbul University; Istanbul Turkey
| | - Omer Faruk Karatas
- Molecular Biology and Genetics Department; Erzurum Technical University; Erzurum Turkey
| | - Seda Salman Yilmaz
- Department of Medical Genetics; Istanbul University, Cerrahpasa Medical School; Istanbul Turkey
| | - Ilknur Suer
- Department of Internal Medicine, Division of Medical Genetics; Istanbul University; Istanbul Turkey
| | - Bugra Ozer
- Advanced Genomics and Bioinformatics Research Center; The Scientific and Technological Research Council of Turkey (TUBITAK-BILGEM); Kocaeli Turkey
| | - Betul Yuceturk
- Advanced Genomics and Bioinformatics Research Center; The Scientific and Technological Research Council of Turkey (TUBITAK-BILGEM); Kocaeli Turkey
| | - Mustafa Ozen
- Department of Medical Genetics; Istanbul University, Cerrahpasa Medical School; Istanbul Turkey
- Department of Pathology and Immunology; Baylor College of Medicine; Houston Texas
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14
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Genetics and mechanisms leading to human cortical malformations. Semin Cell Dev Biol 2018; 76:33-75. [DOI: 10.1016/j.semcdb.2017.09.031] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 09/21/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
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15
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Duan H, Zhang D, Cheng J, Lu Y, Yuan H. Gene screening facilitates diagnosis of complicated symptoms: A case report. Mol Med Rep 2017; 16:7915-7922. [PMID: 28944914 PMCID: PMC5779872 DOI: 10.3892/mmr.2017.7590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 05/02/2017] [Indexed: 01/22/2023] Open
Abstract
Gene mutation has an important role in disease pathogenesis; therefore, genetic screening is a useful tool for diagnosis. The present study screened pathogenic genes, ectodysplasin A (EDA) and lamin A/C (LMNA), in a patient with suspected syndromic hearing impairment and various other symptoms including tooth and skin abnormalities. Large-scale sequencing of 438 deafness-associated genes and whole-genome sequencing was also performed. The present findings did not identify copy number variation and mutations in EDA; therefore, excluding the possibility of EDA-initiated ectodermal dysplasia syndrome. A synonymous mutation in LMNA, possibly due to a splicing abnormality, did not elucidate the pathogenesis of Hutchinson-Gilford progeria syndrome. Whole-genome sequencing revealed copy number variations or mutations in various candidate genes which may elucidate part of the symptoms observed. The copy number variations and mutations were also used to identify single nucleotide variations (SNVs) in crystallin mu (CRYM), RAB3 GTPase activating protein catalytic subunit 1 (RAB3GAP1) and Wnt family member 10A (WNT10A), implicated in deafness, hypogonadism and tooth/skin abnormalities, respectively. The importance of an existing SNV in CRYM and a novel SNV in RAB3GAP1 in pathogenesis remains to be further elucidated. The WNT10A p.G213S mutation was confirmed to be the etiological cause of tooth agenesis and ectodermal dysplasia as previously described. It was concluded that a mutation in WNT10A may be the reason for some of the symptoms observed in the patient; however, other genes may also be involved for other symptoms. The findings of the present study provide putative gene mutations that require further investigation in order to determine their roles in pathogenesis.
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Affiliation(s)
- Hong Duan
- Department of Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Di Zhang
- Department of Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Jing Cheng
- Department of Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Yu Lu
- Department of Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Huijun Yuan
- Department of Surgery, Institute of Otolaryngology, Chinese PLA General Hospital, Beijing 100853, P.R. China
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Moussa S, Grabner G, Ruckhofer J, Dietrich M, Reitsamer H. Genetics in Keratoconus - What is New? Open Ophthalmol J 2017; 11:201-210. [PMID: 28932336 PMCID: PMC5585456 DOI: 10.2174/1874364101711010201] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 04/01/2017] [Accepted: 06/14/2017] [Indexed: 11/22/2022] Open
Abstract
Background: Keratoconus is characterized as a bilateral, progressive, non-inflammatory thinning of the cornea resulting in blurred vision due to irregular astigmatism. Keratoconus has a multifactorial etiology, with multiple genetic and environmental components contributing to the disease pathophysiology. Several genomic loci and genes have been identified that highlight the complex molecular etiology of this disease. Conclusion: The review focuses on current knowledge of these genetic risk factors associated with keratoconus.
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Affiliation(s)
- Sarah Moussa
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Günther Grabner
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Josef Ruckhofer
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Marie Dietrich
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Herbert Reitsamer
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
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State of the Art and Beyond: Anterior Segment Diagnostics Genetic Diagnostics in Corneal Disease. Int Ophthalmol Clin 2017; 57:13-26. [PMID: 28590278 DOI: 10.1097/iio.0000000000000178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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18
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Bikbov MM, Usubov EL, Oganisyan KK, Lobov SL, Khasanova RR, Dzhemileva LU, Khusnutdinova EK. Genetic aspects of keratoconus development. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417040020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bykhovskaya Y, Margines B, Rabinowitz YS. Genetics in Keratoconus: where are we? EYE AND VISION 2016; 3:16. [PMID: 27350955 PMCID: PMC4922054 DOI: 10.1186/s40662-016-0047-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/03/2016] [Indexed: 01/06/2023]
Abstract
Keratoconus (KC) is a non-inflammatory thinning and protrusion of the cornea in which the cornea assumes a conical shape. Complex etiology of this condition at present remains an enigma. Although environmental factors have been involved in KC pathogenesis, strong underlining genetic susceptibility has been proven. The lack of consistent findings among early genetic studies suggested a heterogeneity and complex nature of the genetic contribution to the development of KC. Recently, genome-wide linkage studies (GWLS) and genome-wide association studies (GWAS) were undertaken. Next-generation sequencing (NGS)-based genomic screens are also currently being carried out. Application of these recently developed comprehensive genetic tools led to a much greater success and increased reproducibility of genetic findings in KC. Involvement of the LOX gene identified through GWLS has been confirmed in multiple cohorts of KC patients around the world. KC susceptibility region located at the 2q21.3 chromosomal region near the RAB3GAP1 gene identified through GWAS was independently replicated. Rare variants in the ZNF469 gene (mutated in corneal dystrophy Brittle Cornea Syndrome) and in the TGFBI gene (mutated in multiple corneal epithelial–stromal TGFBI dystrophies) have been repeatedly identified in familial and sporadic KC patients of different ethnicities. Additional comprehensive strategies using quantitative endophenotypes have been successfully employed to bring further understanding to the genetics of KC. Additional genetic determinants including the COL5A1 gene have been identified in the GWAS of KC-related trait central corneal thickness. These recent discoveries confirmed the importance of the endophenotype approach for studying complex genetic diseases such as KC and showed that different connective tissue disorders may have the same genetic determinants.
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Affiliation(s)
- Yelena Bykhovskaya
- Regenerative Medicine Institute and Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, USA ; Cornea Genetic Eye Institute, 50 N. La Cienega Blvd. Suite #340, Beverly Hills, CA 90211 USA
| | - Benjamin Margines
- Cornea Genetic Eye Institute, 50 N. La Cienega Blvd. Suite #340, Beverly Hills, CA 90211 USA
| | - Yaron S Rabinowitz
- Regenerative Medicine Institute and Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, USA ; Cornea Genetic Eye Institute, 50 N. La Cienega Blvd. Suite #340, Beverly Hills, CA 90211 USA ; The Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, USA
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20
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Al-Raddadi HS, Al-Barry MA, Al-Harbi E, Samman MI, Albalawi AM, Basit S. Sequence analysis of the VSX1 and SOD1 genes in families with Keratoconus and a review of the literature. J Taibah Univ Med Sci 2016. [DOI: 10.1016/j.jtumed.2015.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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21
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Mhlanga-Mutangadura T, Johnson GS, Ashwini A, Shelton GD, Wennogle SA, Johnson GC, Kuroki K, O'Brien DP. A Homozygous RAB3GAP1:c.743delC Mutation in Rottweilers with Neuronal Vacuolation and Spinocerebellar Degeneration. J Vet Intern Med 2016; 30:813-8. [PMID: 26968732 PMCID: PMC4913561 DOI: 10.1111/jvim.13921] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 12/28/2015] [Accepted: 02/11/2016] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND A variety of presumed hereditary, neurologic diseases have been reported in young Rottweilers. Overlapping ages of onset and clinical signs have made antemortem diagnosis difficult. One of these diseases, neuronal vacuolation and spinocerebellar degeneration (NVSD) shares clinical and histological features with polyneuropathy with ocular abnormalities and neuronal vacuolation (POANV), a recently described hereditary disease in Black Russian Terriers (BRTs). Dogs with POANV harbor mutations in RAB3GAP1 which codes for a protein involved in membrane trafficking. HYPOTHESIS Rottweilers with NVSD will be homozygous for the RAB3GAP1:c.743delC allele associated with POANV in BRTs. ANIMALS Eight Rottweilers with NVSD confirmed at necropsy, 128 Rottweilers without early onset neurologic signs, and 468 randomly selected dogs from 169 other breeds. METHODS Retrospective case-control study. Dogs were genotyped for the RAB3GAP1:c.743delC allele with an allelic discrimination assay. RESULTS All 8 NVSD-affected dogs were homozygous for the RAB3GAP1:c.743delC allele while the 128 NVSD-free Rottweilers were either homozygous for the reference allele (n = 105) or heterozygous (n = 23) and the 468 genotyped dogs from other breeds were all homozygous for the reference allele. CONCLUSIONS AND CLINICAL IMPORTANCE The RAB3GAP1:c.743delC mutation is associated with a similar phenotype in Rottweilers and BRTs. Identification of the mutation permits a DNA test that can aid in the diagnosis of NVSD and identify carriers of the trait so that breeders can avoid producing affected dogs. Disruption of membrane trafficking could explain the neuronal vacuolation seen in NVSD and other spongiform encephalopathies.
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Affiliation(s)
- T Mhlanga-Mutangadura
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - G S Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - A Ashwini
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - G D Shelton
- Department of Pathology, University of California San Diego, La Jolla, CA
| | - S A Wennogle
- Department of Clinical Sciences, Colorado State University, Fort Collins, CO
| | - G C Johnson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - K Kuroki
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO
| | - D P O'Brien
- Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO
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Mhlanga-Mutangadura T, Johnson GS, Schnabel RD, Taylor JF, Johnson GC, Katz ML, Shelton GD, Lever TE, Giuliano E, Granger N, Shomper J, O'Brien DP. A mutation in the Warburg syndrome gene, RAB3GAP1, causes a similar syndrome with polyneuropathy and neuronal vacuolation in Black Russian Terrier dogs. Neurobiol Dis 2015; 86:75-85. [PMID: 26607784 DOI: 10.1016/j.nbd.2015.11.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Revised: 11/13/2015] [Accepted: 11/18/2015] [Indexed: 11/30/2022] Open
Abstract
An autosomal recessive disease of Black Russian Terriers was previously described as a juvenile-onset, laryngeal paralysis and polyneuropathy similar to Charcot Marie Tooth disease in humans. We found that in addition to an axonal neuropathy, affected dogs exhibit microphthalmia, cataracts, and miotic pupils. On histopathology, affected dogs exhibit a spongiform encephalopathy characterized by accumulations of abnormal, membrane-bound vacuoles of various sizes in neuronal cell bodies, axons and adrenal cells. DNA from an individual dog with this polyneuropathy with ocular abnormalities and neuronal vacuolation (POANV) was used to generate a whole genome sequence which contained a homozygous RAB3GAP1:c.743delC mutation that was absent from 73 control canine whole genome sequences. An additional 12 Black Russian Terriers with POANV were RAB3GAP1:c.743delC homozygotes. DNA samples from 249 Black Russian Terriers with no known signs of POANV were either heterozygotes or homozygous for the reference allele. Mutations in human RAB3GAP1 cause Warburg micro syndrome (WARBM), a severe developmental disorder characterized by abnormalities of the eye, genitals and nervous system including a predominantly axonal peripheral neuropathy. RAB3GAP1 encodes the catalytic subunit of a GTPase activator protein and guanine exchange factor for Rab3 and Rab18 respectively. Rab proteins are involved in membrane trafficking in the endoplasmic reticulum, axonal transport, autophagy and synaptic transmission. The neuronal vacuolation and membranous inclusions and vacuoles in axons seen in this canine disorder likely reflect alterations of these processes. Thus, this canine disease could serve as a model for WARBM and provide insight into its pathogenesis and treatment.
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Affiliation(s)
| | - Gary S Johnson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, USA
| | - Robert D Schnabel
- Division of Animal Sciences, University of Missouri, Columbia, USA; Informatics Institute, University of Missouri, Columbia, USA
| | - Jeremy F Taylor
- Division of Animal Sciences, University of Missouri, Columbia, USA
| | - Gayle C Johnson
- Department of Veterinary Pathobiology, University of Missouri, Columbia, USA
| | - Martin L Katz
- Mason Eye Institute, University of Missouri, Columbia, USA
| | - G Diane Shelton
- Department of Pathology, University of California, San Diego, La Jolla, USA
| | - Teresa E Lever
- Department of Otolaryngology, University of Missouri, Columbia, USA
| | - Elizabeth Giuliano
- Department of Veterinary Medicine & Surgery, University of Missouri, Columbia, USA
| | - Nicolas Granger
- School of Veterinary Sciences, University of Bristol, Langford House, Langford, Somerset BS40 5DU, UK
| | - Jeremy Shomper
- Department of Veterinary Medicine & Surgery, University of Missouri, Columbia, USA
| | - Dennis P O'Brien
- Department of Veterinary Medicine & Surgery, University of Missouri, Columbia, USA.
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A RAB3GAP1 SINE Insertion in Alaskan Huskies with Polyneuropathy, Ocular Abnormalities, and Neuronal Vacuolation (POANV) Resembling Human Warburg Micro Syndrome 1 (WARBM1). G3-GENES GENOMES GENETICS 2015; 6:255-62. [PMID: 26596647 PMCID: PMC4751546 DOI: 10.1534/g3.115.022707] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We observed a hereditary phenotype in Alaskan Huskies that was characterized by polyneuropathy with ocular abnormalities and neuronal vacuolation (POANV). The affected dogs developed a progressive severe ataxia, which led to euthanasia between 8 and 16 months of age. The pedigrees were consistent with a monogenic autosomal recessive inheritance. We localized the causative genetic defect to a 4 Mb interval on chromosome 19 by a combined linkage and homozygosity mapping approach. Whole genome sequencing of one affected dog, an obligate carrier, and an unrelated control revealed a 218-bp SINE insertion into exon 7 of the RAB3GAP1 gene. The SINE insertion was perfectly associated with the disease phenotype in a cohort of 43 Alaskan Huskies, and it was absent from 541 control dogs of diverse other breeds. The SINE insertion induced aberrant splicing and led to a transcript with a greatly altered exon 7. RAB3GAP1 loss-of-function variants in humans cause Warburg Micro Syndrome 1 (WARBM1), which is characterized by additional developmental defects compared to canine POANV, whereas Rab3gap1-deficient mice have a much milder phenotype than either humans or dogs. Thus, the RAB3GAP1 mutant Alaskan Huskies provide an interesting intermediate phenotype that may help to better understand the function of RAB3GAP1 in development. Furthermore, the identification of the presumed causative genetic variant will enable genetic testing to avoid the nonintentional breeding of affected dogs.
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Two novel homozygous RAB3GAP1 mutations cause Warburg micro syndrome. Hum Genome Var 2015; 2:15034. [PMID: 27081543 PMCID: PMC4785564 DOI: 10.1038/hgv.2015.34] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Revised: 08/07/2015] [Accepted: 08/11/2015] [Indexed: 11/30/2022] Open
Abstract
Warburg micro syndrome is an autosomal recessive disease where patients present with optic, neurologic and genital symptoms. Until now, four disease genes for Warburg micro syndrome, RAB3GAP1, RAB3GAP2, RAB18 and TBC1D20, have been identified. Here, we report two novel homozygous RAB3GAP1 mutations (c.22G>T, p.Glu8* and c.1353delA, p.Pro452Hisfs*5) in two consanguineous families by whole-exome sequencing.
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Abstract
Malformations of cortical development (MCDs) are a common cause of neurodevelopmental delay and epilepsy and are caused by disruptions in the normal development of the cerebral cortex. Several causative genes have been identified in patients with MCD. There is increasing evidence of role of de novo mutations, including those occurring post fertilization, in MCD. These somatic mutations may not be detectable by traditional methods of genetic testing performed on blood DNA. Identification of the genetic cause can help in guiding families in future pregnancies. Research has highlighted how elucidation of key molecular pathways can also allow for targeted therapeutic interventions.
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Affiliation(s)
- Saumya S Jamuar
- Department of Paediatrics, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore 229899, Singapore; Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA; Paediatrics Academic Programme, Duke-NUS Graduate Medical School, 8 College Road, Singapore 169857, Singapore
| | - Christopher A Walsh
- Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02138, USA.
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The association of RAB18 gene polymorphism (rs3765133) with cerebellar volume in healthy adults. THE CEREBELLUM 2015; 13:616-22. [PMID: 24996981 DOI: 10.1007/s12311-014-0579-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Genetic factors are responsible for the development of the human brain. Certain genetic factors are known to increase the risk of common brain disorders and affect the brain structure. Therefore, even in healthy people, these factors have a role in the development of specific brain regions. Loss-of-function mutations in the RAB18 gene (RAB18) cause Warburg Micro syndrome, which is associated with reduced brain size and deformed brain structures. In this study, we hypothesized that the RAB18 variant might influence regional brain volumes in healthy people. The study participants comprised 246 normal volunteers between 21 and 59 years of age (mean age of 37.8 ± 12.0 years; 115 men, 131 women). Magnetic resonance imaging (MRI) and genotypes of RAB18 rs3765133 were examined for each participant. The differences in regional brain volumes between T homozygotes and A-allele carriers were tested using voxel-based morphometry. The results showed that RAB18 rs3765133 T homozygote group exhibited larger gray matter (GM) volume in the left middle temporal and inferior frontal gyrus of the cerebrum than the A-allele carriers. An opposite effect was observed in both the posterior lobes and right tonsil of the cerebellum, in which the GM volume of RAB18 rs3765133 T homozygotes was smaller than that of the A-allele carriers (all P FWE < 0.05). Our findings suggest that RAB18 rs3765133 polymorphism affects the deve-lopment of specific brain regions, particularly the cerebellum, in healthy people.
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The genetic and environmental factors for keratoconus. BIOMED RESEARCH INTERNATIONAL 2015; 2015:795738. [PMID: 26075261 PMCID: PMC4449900 DOI: 10.1155/2015/795738] [Citation(s) in RCA: 233] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 12/22/2022]
Abstract
Keratoconus (KC) is the most common cornea ectatic disorder. It is characterized by a cone-shaped thin cornea leading to myopia, irregular astigmatism, and vision impairment. It affects all ethnic groups and both genders. Both environmental and genetic factors may contribute to its pathogenesis. This review is to summarize the current research development in KC epidemiology and genetic etiology. Environmental factors include but are not limited to eye rubbing, atopy, sun exposure, and geography. Genetic discoveries have been reviewed with evidence from family-based linkage analysis and fine mapping in linkage region, genome-wide association studies, and candidate genes analyses. A number of genes have been discovered at a relatively rapid pace. The detailed molecular mechanism underlying KC pathogenesis will significantly advance our understanding of KC and promote the development of potential therapies.
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Arroyo-Carrera I, de Zaldívar Tristancho MS, Bermejo-Sánchez E, Martínez-Fernández ML, López-Lafuente A, MacDonald A, Zúñiga Á, Luis Gómez-Skarmeta J, Luisa Martínez-Frías M. Deletion 1q43-44 in a patient with clinical diagnosis of Warburg-Micro syndrome. Am J Med Genet A 2015; 167:1243-51. [PMID: 25899426 DOI: 10.1002/ajmg.a.36878] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 10/17/2014] [Indexed: 11/11/2022]
Abstract
Warburg-Micro syndrome (WARBM) is an autosomal recessive syndrome characterized by microcephaly, microphthalmia, microcornea, congenital cataracts, optic atrophy and central nervous system malformations. This syndrome is caused by mutations in the RAB3GAP1/2 and RAB18 genes, part of the Rab family, and in the TBC1D20 gene, which contributes to lipid droplet formation/metabolism. Here we present a patient with clinical diagnosis of WARBM syndrome, who did not have mutations in either the RAB3GAP1/2 genes, in the main exons of RAB18, nor in the TBC1D20 gene. However, the analysis with CGH-array detected a 9.6 Mb deletion at 1q43-qter. We performed a genotype-phenotype correlation using 20 previously published patients in whom the coordinates of the deleted regions were defined. The comparative analysis revealed that the current patient and three of the other 20 patients share the loss of six genes, four of which are related with the family of G proteins, and are strongly expressed in the brain, retina, heart and kidney. Consequently, their haploinsufficiency may result in different combinations of clinical alterations, including some of those of WARBM syndrome. In addition, the haploinsufficiency of other genes may contribute to other defects and clinical variability. Additionally, for the genotype-phenotype correlation, one must also consider molecular pathways that can result in the observed alterations. To early confirm a genetic diagnosis is essential for the patient and family. The current patient was considered as having a recessive syndrome, but since he had a "de novo" deletion, there was not an increased recurrence risk.
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Affiliation(s)
- Ignacio Arroyo-Carrera
- Servicio de Pediatría, Hospital San Pedro de Alcántara, Cáceres, Spain.,Spanish Collaborative Study of Congenital Malformations (ECEMC), Spain.,CIBER de Enfermedades Raras (CIBERER) (U724), Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain
| | - María Solo de Zaldívar Tristancho
- Servicio de Pediatría, Hospital San Pedro de Alcántara, Cáceres, Spain.,Spanish Collaborative Study of Congenital Malformations (ECEMC), Spain
| | - Eva Bermejo-Sánchez
- Spanish Collaborative Study of Congenital Malformations (ECEMC), Spain.,CIBER de Enfermedades Raras (CIBERER) (U724), Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain.,Centro de Investigación sobre Anomalías Congénitas (CIAC), Instituto de Salud Carlos III, Madrid, Spain.,Instituto de Investigación de Enfermedades Raras (IIER), Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain
| | - María Luisa Martínez-Fernández
- Spanish Collaborative Study of Congenital Malformations (ECEMC), Spain.,CIBER de Enfermedades Raras (CIBERER) (U724), Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain.,Centro de Investigación sobre Anomalías Congénitas (CIAC), Instituto de Salud Carlos III, Madrid, Spain
| | | | - Alexandra MacDonald
- Spanish Collaborative Study of Congenital Malformations (ECEMC), Spain.,Centro de Investigación sobre Anomalías Congénitas (CIAC), Instituto de Salud Carlos III, Madrid, Spain
| | - Ángel Zúñiga
- Servicio de Genética y Biología Molecular, Hospital Universitario de la Ribera, Alzira, Valencia, Spain
| | | | - María Luisa Martínez-Frías
- Spanish Collaborative Study of Congenital Malformations (ECEMC), Spain.,CIBER de Enfermedades Raras (CIBERER) (U724), Instituto de Salud Carlos III, Ministerio de Economía y Competitividad, Madrid, Spain.,Centro de Investigación sobre Anomalías Congénitas (CIAC), Instituto de Salud Carlos III, Madrid, Spain.,Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, Madrid, Spain
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Park AK, Liegel RP, Ronchetti A, Ebert AD, Geurts A, Sidjanin DJ. Targeted disruption of Tbc1d20 with zinc-finger nucleases causes cataracts and testicular abnormalities in mice. BMC Genet 2014; 15:135. [PMID: 25476608 PMCID: PMC4266191 DOI: 10.1186/s12863-014-0135-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 11/24/2014] [Indexed: 12/27/2022] Open
Abstract
Background Loss-of-function mutations in TBC1D20 cause Warburg Micro syndrome 4 (WARBM4), which is an autosomal recessive syndromic disorder characterized by eye, brain, and genital abnormalities. Blind sterile (bs) mice carry a Tbc1d20-null mutation and exhibit cataracts and testicular phenotypes similar to those observed in WARBM4 patients. In addition to TBC1D20, mutations in RAB3GAP1, RAB3GAP2 and RAB18 cause WARBM1-3 respectively. However, regardless of which gene harbors the causative mutation, all individuals affected with WARBM exhibit indistinguishable clinical presentations. In contrast, bs, Rab3gap1-/-, and Rab18-/- mice exhibit distinct phenotypes; this phenotypic variability of WARBM mice was previously attributed to potential compensatory mechanisms. Rab3gap1-/- and Rab18-/- mice were genetically engineered using standard approaches, whereas the Tbc1d20 mutation in the bs mice arose spontaneously. There is the possibility that another unidentified mutation within the bs linkage disequilibrium may be contributing to the bs phenotypes and thus contributing to the phenotypic variability in WARBM mice. The goal of this study was to establish the phenotypic consequences in mice caused by the disruption of the Tbc1d20 gene. Results The zinc finger nuclease (ZFN) mediated genomic editing generated a Tbc1d20 c.[418_426del] deletion encoding a putative TBC1D20-ZFN protein with an in-frame p.[H140_Y143del] deletion within the highly conserved TBC domain. The evaluation of Tbc1d20ZFN/ZFN eyes identified severe cataracts and thickened pupillary sphincter muscle. Tbc1d20ZFN/ZFN males are infertile and the analysis of the seminiferous tubules identified disrupted acrosomal development. The compound heterozygote Tbc1d20ZFN/bs mice, generated from an allelic bs/+ X Tbc1d20ZFN/+ cross, exhibited cataracts and aberrant acrosomal development indicating a failure to complement. Conclusions Our findings show that the disruption of Tbc1d20 in mice results in cataracts and aberrant acrosomal formation, thus establishing bs and Tbc1d20ZFN/ZFN as allelic variants. Although the WARBM molecular disease etiology remains unclear, both the bs and Tbc1d20ZFN/ZFN mice are excellent model organisms for future studies to establish TBC1D20-mediated molecular and cellular functions.
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Affiliation(s)
- Anna Kyunglim Park
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA.
| | - Ryan P Liegel
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA.
| | - Adam Ronchetti
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA.
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA.
| | - Aron Geurts
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA. .,Human and Molecular Genetics Center, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA.
| | - Duska J Sidjanin
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA. .,Human and Molecular Genetics Center, Medical College of Wisconsin, 8701 Watertown Plank, Milwaukee, WI, 53226, USA.
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Large homozygous RAB3GAP1 gene microdeletion causes Warburg micro syndrome 1. Orphanet J Rare Dis 2014; 9:113. [PMID: 25332050 PMCID: PMC4224754 DOI: 10.1186/s13023-014-0113-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 07/07/2014] [Indexed: 11/20/2022] Open
Abstract
Warburg micro syndrome (WARBM) is a genetic heterogeneous disease characterized by microcephaly, intellectual disability, brain, ocular, and endocrine anomalies. WARBM1-4 can be caused by biallelic mutations of the RAB3GAP1 (RAB3 GTPase-activating protein 1), RAB3GAP2, RAB18 (RAS-associated protein RAB18), or TBC1D20 (TBC1 domain protein, member 20) gene, respectively. Here, we delineate the so far largest intragenic homozygous RAB3GAP1 microdeletion. Despite the size of the RAB3GAP1 gene deletion, the patient phenotype is mainly consistent with that of other WARBM1 patients, supporting strongly the theory that WARBM1 is caused by a loss of RAB3GAP1 function. We further highlight osteopenia as a feature of WARBM1.
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Greally MT, Robinson E, Allen NM, O'Donovan D, Crolla JA. De novo interstitial deletion 2q14.1q22.1: is there a recognizable phenotype? Am J Med Genet A 2014; 164A:3194-202. [PMID: 25263257 DOI: 10.1002/ajmg.a.36786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 08/21/2014] [Indexed: 12/29/2022]
Abstract
In this report we describe a male patient with a rare de novo interstitial deletion of chromosome 2q14.1-q22.1. His karyotype was reported as 46,XY,del(2)(q13q21) but subsequent array comparative genomic hybridization (array CGH) analysis redefined the deletion breakpoints as 2q14.1 and 2q22.1. Eight patients have been reported with deletions either within or spanning the region 2q13 or 2q14 to 2q22.1. In five patients the diagnosis was made by karyotype analysis alone and in three reported patients and the proband array CGH analysis was also performed. When the proband was compared with the eight previously reported patients it was apparent that they shared many clinical findings suggesting that patients with a de novo interstitial deletion involving 2q13 or 2q14 to 2q21 or 2q22 may have a recognizable phenotype. There are 14 known disease-associated genes in the deleted region of 2q14.1-q22.1 and their possible phenotypic effects on the proband and the eight previously reported patients are discussed.
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Affiliation(s)
- Marie T Greally
- National Centre for Medical Genetics, Our Lady's Children's Hospital, Crumlin, Dublin, Ireland
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Jeyabalan N, Shetty R, Ghosh A, Anandula VR, Ghosh AS, Kumaramanickavel G. Genetic and genomic perspective to understand the molecular pathogenesis of keratoconus. Indian J Ophthalmol 2014; 61:384-8. [PMID: 23925319 PMCID: PMC3775069 DOI: 10.4103/0301-4738.116055] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Keratoconus (KC; Mendelian Inheritance in Man (OMIM) 14830) is a bilateral, progressive corneal defect affecting all ethnic groups around the world. It is the leading cause of corneal transplantation. The age of onset is at puberty, and the disorder is progressive until the 3rd–4th decade of life when it usually arrests. It is one of the major ocular problems with significant social and economic impacts as the disease affects young generation. Although genetic and environmental factors are associated with KC, but the precise etiology is still elusive. Results from complex segregation analysis suggests that genetic abnormalities may play an essential role in the susceptibility to KC. Due to genetic heterogeneity, a recent study revealed 17 different genomic loci identified in KC families by linkage mapping in various populations. The focus of this review is to provide a concise update on the current knowledge of the genetic basis of KC and genomic approaches to understand the disease pathogenesis.
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Affiliation(s)
- Nallathambi Jeyabalan
- Department of Genetics, Grow Laboratory, Grow Laboratory, Narayana Nethralaya Eye Hospital, Bangalore, Karnataka, India
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Seltzer LE, Paciorkowski AR. Genetic disorders associated with postnatal microcephaly. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2014; 166C:140-55. [PMID: 24839169 DOI: 10.1002/ajmg.c.31400] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Several genetic disorders are characterized by normal head size at birth, followed by deceleration in head growth resulting in postnatal microcephaly. Among these are classic disorders such as Angelman syndrome and MECP2-related disorder (formerly Rett syndrome), as well as more recently described clinical entities associated with mutations in CASK, CDKL5, CREBBP, and EP300 (Rubinstein-Taybi syndrome), FOXG1, SLC9A6 (Christianson syndrome), and TCF4 (Pitt-Hopkins syndrome). These disorders can be identified clinically by phenotyping across multiple neurodevelopmental and neurobehavioral realms, and enough data are available to recognize these postnatal microcephaly disorders as separate diagnostic entities in their own right. A second diagnostic grouping, comprised of Warburg MICRO syndrome, Cockayne syndrome, and Cerebral-oculo-facial skeletal syndrome, share similar features of somatic growth failure, ophthalmologic, and dysmorphologic features. Many postnatal microcephaly syndromes are caused by mutations in genes important in the regulation of gene expression in the developing forebrain and hindbrain, although important synaptic structural genes also play a role. This is an emerging group of disorders with a fascinating combination of brain malformations, specific epilepsies, movement disorders, and other complex neurobehavioral abnormalities.
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Baulac S, Lenk GM, Dufresnois B, Ouled Amar Bencheikh B, Couarch P, Renard J, Larson PA, Ferguson CJ, Noé E, Poirier K, Hubans C, Ferreira S, Guerrini R, Ouazzani R, El Hachimi KH, Meisler MH, Leguern E. Role of the phosphoinositide phosphatase FIG4 gene in familial epilepsy with polymicrogyria. Neurology 2014; 82:1068-75. [PMID: 24598713 DOI: 10.1212/wnl.0000000000000241] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE The aim of this study was to identify the causal gene in a consanguineous Moroccan family with temporo-occipital polymicrogyria, psychiatric manifestations, and epilepsy, previously mapped to the 6q16-q22 region. METHODS We used exome sequencing and analyzed candidate variants in the 6q16-q22 locus, as well as a rescue assay in Fig4-null mouse fibroblasts and immunohistochemistry of Fig4-null mouse brains. RESULTS A homozygous missense mutation (p.Asp783Val) in the phosphoinositide phosphatase gene FIG4 was identified. Pathogenicity of the variant was supported by impaired rescue of the enlarged vacuoles in transfected fibroblasts from Fig4-deficient mice. Histologic examination of Fig4-null mouse brain revealed neurodevelopmental impairment in the hippocampus, cortex, and cerebellum as well as impaired cerebellar gyration/foliation reminiscent of human cortical malformations. CONCLUSIONS This study extends the spectrum of phenotypes associated with FIG4 mutations to include cortical malformation associated with seizures and psychiatric manifestations, in addition to the previously described Charcot-Marie-Tooth disease type 4J and Yunis-Varón syndrome.
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Affiliation(s)
- Stéphanie Baulac
- From INSERM (S.B., B.D., B.O.A.B., P.C., J.R., E.N., K.H.E.H., E.L.), U1127; Sorbonne Universités, UPMC Univ Paris 06 (S.B., B.D., B.O.A.B., P.C., J.R., E.N., K.H.E.H., E.L.), UM 75; CNRS (S.B., B.D., B.O.A.B., P.C., J.R., E.N., K.H.E.H., E.L.), UMR 7225, ICM, Paris, ICM, (S.B., B.D., B.O.A.B., P.C., J.R., E.N., K.H.E.H., E.L.) Paris, F-75013 Paris, France; Department of Human Genetics (G.M.L., P.A.L., C.J.F., M.H.M.), University of Michigan, Ann Arbor; Service de Neurophysiologie Clinique (B.O.A.B.), Hôpital des Spécialités, Centre Hospitalier Ibn Sina Rabat, Morocco; Genetics and Pathophysiology of Neurodevelopmental and Neuromuscular Diseases (K.P.), Cochin Institute, Paris; GenoScreen (C.H., S.F.), Lille, France; Neuroscience Department (R.G.), Children's Hospital A. Meyer, University of Florence and IRCCS Stella Maris, Pisa, Italy; Laboratoire de Neurogénétique (K.H.E.H.), Ecole Pratique des Hautes Etudes, Paris; and Département de Génétique et de Cytogénétique (E.L.), AP-HP Groupe hospitalier Pitié-Salpêtrière, Paris, France
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Liegel R, Handley M, Ronchetti A, Brown S, Langemeyer L, Linford A, Chang B, Morris-Rosendahl D, Carpanini S, Posmyk R, Harthill V, Sheridan E, Abdel-Salam G, Terhal P, Faravelli F, Accorsi P, Giordano L, Pinelli L, Hartmann B, Ebert A, Barr F, Aligianis I, Sidjanin D. Loss-of-function mutations in TBC1D20 cause cataracts and male infertility in blind sterile mice and Warburg micro syndrome in humans. Am J Hum Genet 2013; 93:1001-14. [PMID: 24239381 DOI: 10.1016/j.ajhg.2013.10.011] [Citation(s) in RCA: 93] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 09/20/2013] [Accepted: 10/11/2013] [Indexed: 12/22/2022] Open
Abstract
blind sterile (bs) is a spontaneous autosomal-recessive mouse mutation discovered more than 30 years ago. Phenotypically, bs mice exhibit nuclear cataracts and male infertility; genetic analyses assigned the bs locus to mouse chromosome 2. In this study, we first positionally cloned the bs locus and identified a putative causative mutation in the Tbc1d20 gene. Functional analysis established the mouse TBC1D20 protein as a GTPase-activating protein (GAP) for RAB1 and RAB2, and bs as a TBC1D20 loss-of-function mutation. Evaluation of bs mouse embryonic fibroblasts (mEFs) identified enlarged Golgi morphology and aberrant lipid droplet (LD) formation. Based on the function of TBC1D20 as a RABGAP and the bs cataract and testicular phenotypes, we hypothesized that mutations in TBC1D20 may contribute to Warburg micro syndrome (WARBM); WARBM constitutes a spectrum of disorders characterized by eye, brain, and endocrine abnormalities caused by mutations in RAB3GAP1, RAB3GAP2, and RAB18. Sequence analysis of a cohort of 77 families affected by WARBM identified five distinct TBC1D20 loss-of-function mutations, thereby establishing these mutations as causative of WARBM. Evaluation of human fibroblasts deficient in TBC1D20 function identified aberrant LDs similar to those identified in the bs mEFs. Additionally, our results show that human fibroblasts deficient in RAB18 and RAB3GAP1 function also exhibit aberrant LD formation. These findings collectively indicate that a defect in LD formation/metabolism may be a common cellular abnormality associated with WARBM, although it remains unclear whether abnormalities in LD metabolism are contributing to WARBM disease pathology.
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Handley MT, Morris-Rosendahl DJ, Brown S, Macdonald F, Hardy C, Bem D, Carpanini SM, Borck G, Martorell L, Izzi C, Faravelli F, Accorsi P, Pinelli L, Basel-Vanagaite L, Peretz G, Abdel-Salam GMH, Zaki MS, Jansen A, Mowat D, Glass I, Stewart H, Mancini G, Lederer D, Roscioli T, Giuliano F, Plomp AS, Rolfs A, Graham JM, Seemanova E, Poo P, García-Cazorla A, Edery P, Jackson IJ, Maher ER, Aligianis IA. Mutation spectrum in RAB3GAP1, RAB3GAP2, and RAB18 and genotype-phenotype correlations in warburg micro syndrome and Martsolf syndrome. Hum Mutat 2013; 34:686-96. [PMID: 23420520 DOI: 10.1002/humu.22296] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 02/07/2013] [Indexed: 01/10/2023]
Abstract
Warburg Micro syndrome and Martsolf syndrome (MS) are heterogeneous autosomal-recessive developmental disorders characterized by brain, eye, and endocrine abnormalities. Causative biallelic germline mutations have been identified in RAB3GAP1, RAB3GAP2, or RAB18, each of which encode proteins involved in membrane trafficking. This report provides an up to date overview of all known disease variants identified in 29 previously published families and 52 new families. One-hundred and forty-four Micro and nine Martsolf families were investigated, identifying mutations in RAB3GAP1 in 41% of cases, mutations in RAB3GAP2 in 7% of cases, and mutations in RAB18 in 5% of cases. These are listed in Leiden Open source Variation Databases, which was created by us for all three genes. Genotype-phenotype correlations for these genes have now established that the clinical phenotypes in Micro syndrome and MS represent a phenotypic continuum related to the nature and severity of the mutations present in the disease genes, with more deleterious mutations causing Micro syndrome and milder mutations causing MS. RAB18 has not yet been linked to the RAB3 pathways, but mutations in all three genes cause an indistinguishable phenotype, making it likely that there is some overlap. There is considerable genetic heterogeneity for these disorders and further gene identification will help delineate these pathways.
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Affiliation(s)
- Mark T Handley
- MRC Human Genetics Unit, Medical Research Council and Institute of Genetics and Molecular Medicine, University of Edinburgh, Scotland, UK
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Youssef G, Gerner L, Naeem AS, Ralph O, Ono M, O'Neill CA, O'Shaughnessy RFL. Rab3Gap1 mediates exocytosis of Claudin-1 and tight junction formation during epidermal barrier acquisition. Dev Biol 2013; 380:274-85. [PMID: 23685254 PMCID: PMC3995087 DOI: 10.1016/j.ydbio.2013.04.034] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 04/26/2013] [Accepted: 04/30/2013] [Indexed: 12/01/2022]
Abstract
Epidermal barrier acquisition during late murine gestation is accompanied by an increase in Akt kinase activity and cJun dephosphorlyation. The latter is directed by the Ppp2r2a regulatory subunit of the Pp2a phosphatase. This was accompanied by a change of Claudin-1 localisation to the cell surface and interaction between Occludin and Claudin-1 which are thought to be required for tight junction formation. The aim of this study was to determine the nature of the barrier defect caused by the loss of AKT/Ppp2r2a function. There was a paracellular barrier defect in rat epidermal keratinocytes expressing a Ppp2r2a siRNA. In Ppp2r2a knockdown cells, Claudin-1 was located to the cytoplasm and its expression was increased. Inhibiting cJun phosphorylation restored barrier function and plasma membrane localisation of Claudin-1. Expression of the Rab3 GTPase activating protein, Rab3Gap1, was restored in Ppp2r2a siRNA cells when cJun phosphorylation was inhibited. During normal mouse epidermal development, Claudin-1 plasma membrane localisation and Rab3Gap1 cell surface expression were co-incident with Akt activation in mouse epidermis, strongly suggesting a role of Rab3Gap1 in epidermal barrier acquisition. Supporting this hypothesis, siRNA knockdown of Rab3Gap1 prevented plasma membrane Claudin-1 expression and the formation of a barrier competent epithelium. Replacing Rab3Gap1 in Ppp2r2a knockdown cells was sufficient to rescue Claudin-1 transport to the cell surface. Therefore these data suggest Rab3Gap1 mediated exocytosis of Claudin-1 is an important component of epidermal barrier acquisition during epidermal development. Barrier acquisition correlates with Ppp2r2a and cell surface Claudin-1 expression. Ppp2r2a knockdown results in a paracellular barrier defect. Ppp2r2a knockdown prevents cell-surface claudin-1 expression in a c-Jun dependent fashion. Barrier rescue by inhibition of c-Jun phosphorylation involves exocytosis and Rab3Gap1. Rab3Gap1 is induced during barrier acquisition and is necessary for cell surface claudin-1.
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Affiliation(s)
- G Youssef
- Livingstone Skin Research Centre for Children, UCL Institute of Child Health, London WC1N 1EH, UK
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Abstract
Micro syndrome (OMIM 60018) and Martsolf syndrome (OMIM 21270) are related rare autosomal recessive disorders characterized by ocular and neurological abnormalities and hypothalamic hypogonadism. Micro syndrome has been associated with causative mutations in three disease genes: RAB3GAP1, RAB3GAP2 and RAB18. Martsolf syndrome has been associated with a mutation in RAB3GAP2. The present review summarizes the current literature on these genes and the proteins they encode.
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Sharif J, Shinkai Y, Koseki H. Is there a role for endogenous retroviruses to mediate long-term adaptive phenotypic response upon environmental inputs? Philos Trans R Soc Lond B Biol Sci 2013; 368:20110340. [PMID: 23166400 DOI: 10.1098/rstb.2011.0340] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Endogenous retroviruses (ERVs) are long terminal repeat-containing virus-like elements that have colonized approximately 10 per cent of the present day mammalian genomes. The intracisternal A particles (IAPs) are a class of ERVs that is currently highly active in the rodents. IAP elements can influence the transcription profile of nearby genes by providing functional promoter elements and modulating local epigenetic landscape through changes in DNA methylation and histone (H3K9) modifications. Despite the potential role for IAPs in gene regulation, the precise genomic locations where these elements are integrated are not well understood. To address this issue, we have identified more than 400 novel IAP insertion sites within/near annotated genes by searching the murine genome, which suggests that the impact of IAP elements on local and/or global gene regulation could be more profound than was previously expected. On the basis of our independent analyses and already published reports, here we argue that IAPs and ERV elements in general could have an evolutionary role for modulating phenotypic plasticity upon environmental inputs, and that this could be mediated through specific stages of embryonic development such as placentation during which the epigenetic constraints on IAP elements are partially relaxed.
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Affiliation(s)
- Jafar Sharif
- Developmental Genetics Group, RIKEN Research Center for Allergy & Immunology, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, 230-0045 Kanagawa, Japan.
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Al-Owain M, Al-Zahrani J, Al-Bakheet A, Abudheim N, Al-Younes B, Aldhalaan H, Al-Zaidan H, Colak D, Almohaileb F, Abouzied ME, Al-Fadhli F, Meyer B, Kaya N. A novel syndrome of abnormal striatum and congenital cataract: evidence for linkage to chromosomes 11. Clin Genet 2012. [DOI: 10.1111/cge.12066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
| | | | | | | | | | | | | | | | - F Almohaileb
- Department of Radiology; King Faisal Specialist Hospital and Research Centre; Riyadh; Saudi Arabia
| | - ME Abouzied
- Department of Radiology; King Faisal Specialist Hospital and Research Centre; Riyadh; Saudi Arabia
| | - F Al-Fadhli
- Department of Pediatrics; Maternity and Children Hospital; Al-Madinah; Saudi Arabia
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Barkovich AJ, Guerrini R, Kuzniecky RI, Jackson GD, Dobyns WB. A developmental and genetic classification for malformations of cortical development: update 2012. Brain 2012; 135:1348-69. [PMID: 22427329 PMCID: PMC3338922 DOI: 10.1093/brain/aws019] [Citation(s) in RCA: 655] [Impact Index Per Article: 54.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Malformations of cerebral cortical development include a wide range of developmental disorders that are common causes of neurodevelopmental delay and epilepsy. In addition, study of these disorders contributes greatly to the understanding of normal brain development and its perturbations. The rapid recent evolution of molecular biology, genetics and imaging has resulted in an explosive increase in our knowledge of cerebral cortex development and in the number and types of malformations of cortical development that have been reported. These advances continue to modify our perception of these malformations. This review addresses recent changes in our perception of these disorders and proposes a modified classification based upon updates in our knowledge of cerebral cortical development.
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Affiliation(s)
- A James Barkovich
- Neuroradiology, University of California at San Francisco, 505 Parnassus Avenue, San Francisco, CA 94913-0628, USA.
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Abstract
Keratoconus is the most common ectatic disorder of the corneal. Genetic and environmental factors may contribute to its pathogenesis. The focus of this article is to summarize current research into the complex genetics of keratoconus. We discuss the evidence of genetic etiology including family-based linkage studies, twin studies, genetic mutations, and genome-wide association studies. The genes implicated potentially include VSX1, miR-184, DOCK9, SOD1, RAB3GAP1, and HGF. Besides the coding mutations, we also highlight the potential contribution of DNA copy number variants in the pathogenesis of keratoconus. Finally, we present future directions for genetic research in the understanding of the complex genetics of keratoconus and its clinical significance. As new functional, candidate genes for keratoconus are being discovered at a rapid pace, the molecular genetic mechanisms underlying keratoconus pathogenesis will advance our understanding of keratoconus and promote the development of a novel therapy.
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Affiliation(s)
- Joshua Wheeler
- Center for Human Genetics, Department of Medicine, Duke University Medical Center, Durham, NC, USA 27710
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Li X, Bykhovskaya Y, Haritunians T, Siscovick D, Aldave A, Szczotka-Flynn L, Iyengar SK, Rotter JI, Taylor KD, Rabinowitz YS. A genome-wide association study identifies a potential novel gene locus for keratoconus, one of the commonest causes for corneal transplantation in developed countries. Hum Mol Genet 2011; 21:421-9. [PMID: 21979947 DOI: 10.1093/hmg/ddr460] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Keratoconus is a condition in which the cornea progressively thins over time, and is a major cause for cornea transplantation. To identify keratoconus susceptibility regions, we performed a comprehensive genome-wide association study (GWAS) using a discovery and replication design. A discovery panel of 222 keratoconus Caucasian patients and 3324 Caucasian controls was genotyped using Illumina 370K beadchips. Further associated and fine-mapping single nucleotide polymorphisms (SNPs) (n= 4905) were genotyped in an independent replication case-control panel of 304 cases and 518 controls and a family panel of 307 subjects in 70 families. Logistic regression models implemented in PLINK were performed to test associations in case-control samples with and without principal component (PC) adjustments. Generalized estimation equation models accounting for familial correlations implemented in GWAF were used for association testing in families. No genome-wide associations were identified in the discovery GWAS panel. From the initial testing without adjustments for PCs, the top three SNPs located at 3p26 (rs6442925), 2q21.3 (rs4954218) and 19q13.3 (rs1428642) were identified with unadjusted P-values of 6.5 × 10(-8), 2.4 × 10(-7) and 3.1 × 10(-7), respectively. After adjustments for PCs, rs1428642 became the most significant through the genome with a P-value of 1.4 × 10(-6), while rs6442925 and rs4954218 were less significant (P= 1.9 × 10(-5) and 2.6 × 10(-4)). SNP rs4954218 was confirmed in two independent replication panels with P-values of 0.004 and 0.009, respectively. Meta-analysis revealed a highest association at rs4954218 with adjusted P= 1.6 × 10(-7) (unadjusted P= 1.2 × 10(-9)). These findings suggest SNP rs4954218, located near the RAB3GAP1 gene, previously reported to be associated with corneal malformation, is a potential susceptibility locus for keratoconus.
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Affiliation(s)
- Xiaohui Li
- Cornea Genetic Eye Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Loss-of-function mutations in RAB18 cause Warburg micro syndrome. Am J Hum Genet 2011; 88:499-507. [PMID: 21473985 DOI: 10.1016/j.ajhg.2011.03.012] [Citation(s) in RCA: 137] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 03/08/2011] [Accepted: 03/16/2011] [Indexed: 12/24/2022] Open
Abstract
Warburg Micro syndrome and Martsolf syndrome are heterogenous autosomal-recessive developmental disorders characterized by brain, eye, and endocrine abnormalities. Previously, identification of mutations in RAB3GAP1 and RAB3GAP2 in both these syndromes implicated dysregulation of the RAB3 cycle (which controls calcium-mediated exocytosis of neurotransmitters and hormones) in disease pathogenesis. RAB3GAP1 and RAB3GAP2 encode the catalytic and noncatalytic subunits of the hetrodimeric enzyme RAB3GAP (RAB3GTPase-activating protein), a key regulator of the RAB3 cycle. We performed autozygosity mapping in five consanguineous families without RAB3GAP1/2 mutations and identified loss-of-function mutations in RAB18. A c.71T > A (p.Leu24Gln) founder mutation was identified in four Pakistani families, and a homozygous exon 2 deletion (predicted to result in a frameshift) was found in the fifth family. A single family whose members were compound heterozygotes for an anti-termination mutation of the stop codon c.619T > C (p.X207QextX20) and an inframe arginine deletion c.277_279 del (p.Arg93 del) were identified after direct gene sequencing and multiplex ligation-dependent probe amplification (MLPA) of a further 58 families. Nucleotide binding assays for RAB18(Leu24Gln) and RAB18(Arg93del) showed that these mutant proteins were functionally null in that they were unable to bind guanine. The clinical features of Warburg Micro syndrome patients with RAB3GAP1 or RAB3GAP2 mutations and RAB18 mutations are indistinguishable, although the role of RAB18 in trafficking is still emerging, and it has not been linked previously to the RAB3 pathway. Knockdown of rab18 in zebrafish suggests that it might have a conserved developmental role. Our findings imply that RAB18 has a critical role in human brain and eye development and neurodegeneration.
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Borck G, Wunram H, Steiert A, Volk AE, Körber F, Roters S, Herkenrath P, Wollnik B, Morris-Rosendahl DJ, Kubisch C. A homozygous RAB3GAP2 mutation causes Warburg Micro syndrome. Hum Genet 2010; 129:45-50. [PMID: 20967465 DOI: 10.1007/s00439-010-0896-2] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 09/25/2010] [Indexed: 11/29/2022]
Abstract
Warburg Micro syndrome and Martsolf syndrome are clinically overlapping autosomal recessive conditions characterized by congenital cataracts, microphthalmia, postnatal microcephaly, and developmental delay. The neurodevelopmental and ophthalmological phenotype is more severe in Warburg Micro syndrome in which cerebral malformations and severe motor and mental retardation are common. While biallelic loss-of-function mutations in RAB3GAP1 are present in the majority of patients with Warburg Micro syndrome; a hypomorphic homozygous splicing mutation of RAB3GAP2 has been reported in a single family with Martsolf syndrome. Here, we report a novel homozygous RAB3GAP2 small in-frame deletion, c.499_507delTTCTACACT (p.Phe167_Thr169del) that causes Warburg Micro syndrome in a girl from a consanguineous Turkish family presenting with congenital cataracts, microphthalmia, absent visually evoked potentials, microcephaly, polymicrogyria, hypoplasia of the corpus callosum, and severe developmental delay. No RAB3GAP2 mutations were detected in ten additional unrelated patients with RAB3GAP1-negative Warburg Micro syndrome, consistent with further genetic heterogeneity. In conclusion, we provide evidence that RAB3GAP2 mutations are not specific to Martsolf syndrome. Rather, our findings suggest that loss-of-function mutations of RAB3GAP1 as well as functionally severe RAB3GAP2 mutations cause Warburg Micro syndrome while hypomorphic RAB3GAP2 mutations can result in the milder Martsolf phenotype. Thus, a phenotypic severity gradient may exist in the RAB3GAP-associated disease continuum (the "Warburg-Martsolf syndrome") which is presumably determined by the mutant gene and the nature of the mutation.
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Affiliation(s)
- Guntram Borck
- Institute of Human Genetics, University of Cologne, Kerpener Str. 34, 50931, Cologne, Germany.
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