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Solaki M, Wissinger B, Kohl S, Reuter P. Functional evaluation allows ACMG/AMP-based re-classification of CNGA3 variants associated with achromatopsia. Genet Med 2023; 25:100979. [PMID: 37689994 DOI: 10.1016/j.gim.2023.100979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/11/2023] Open
Abstract
PURPOSE CNGA3 encoding the main subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors is one of the major disease-associated genes for achromatopsia. Most CNGA3 variants are missense variants with the majority being functionally uncharacterized and therefore hampering genetic diagnosis. In light of potential gene therapy, objective variant pathogenicity assessment is essential. METHODS We established a medium-throughput aequorin-based luminescence bioassay allowing mutant CNGA3 channel function assessment via quantification of CNGA3 channel-mediated calcium influx in a cell culture system, thereby enabling American College of Medical Genetics and Genomics/Association for Molecular Pathology-based variant re-classification. RESULTS We provide functional read-out obtained for 150 yet uncharacterized CNGA3 missense substitutions of which 55 were previously categorized as variants of uncertain significance (VUS) identifying 25 as functionally normal and 125 as functionally abnormal. These data enabled the American College of Medical Genetics and Genomics/ Association for Molecular Pathology-based variant re-classification of 52/55 VUS as either benign, likely benign, or likely pathogenic reaching a VUS re-classification rate of 94.5%. CONCLUSION Our aequorin-based bioassay allows functionally ensured clinical variant interpretation for 150 CNGA3 missense variants enabling and supporting VUS re-classification and assuring molecular diagnosis to patients affected by CNGA3-associated achromatopsia, hereby identifying patients eligible for future gene therapy trials on this disease.
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Affiliation(s)
- Maria Solaki
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
| | - Peggy Reuter
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
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Biology, Pathobiology and Gene Therapy of CNG Channel-Related Retinopathies. Biomedicines 2023; 11:biomedicines11020269. [PMID: 36830806 PMCID: PMC9953513 DOI: 10.3390/biomedicines11020269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 01/21/2023] Open
Abstract
The visual process begins with the absorption of photons by photopigments of cone and rod photoreceptors in the retina. In this process, the signal is first amplified by a cyclic guanosine monophosphate (cGMP)-based signaling cascade and then converted into an electrical signal by cyclic nucleotide-gated (CNG) channels. CNG channels are purely ligand-gated channels whose activity can be controlled by cGMP, which induces a depolarizing Na+/Ca2+ current upon binding to the channel. Structurally, CNG channels belong to the superfamily of pore-loop cation channels and share structural similarities with hyperpolarization-activated cyclic nucleotide (HCN) and voltage-gated potassium (KCN) channels. Cone and rod photoreceptors express distinct CNG channels encoded by homologous genes. Mutations in the genes encoding the rod CNG channel (CNGA1 and CNGB1) result in retinitis-pigmentosa-type blindness. Mutations in the genes encoding the cone CNG channel (CNGA3 and CNGB3) lead to achromatopsia. Here, we review the molecular properties of CNG channels and describe their physiological and pathophysiological roles in the retina. Moreover, we summarize recent activities in the field of gene therapy aimed at developing the first gene therapies for CNG channelopathies.
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3
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Solaki M, Baumann B, Reuter P, Andreasson S, Audo I, Ayuso C, Balousha G, Benedicenti F, Birch D, Bitoun P, Blain D, Bocquet B, Branham K, Català-Mora J, De Baere E, Dollfus H, Falana M, Giorda R, Golovleva I, Gottlob I, Heckenlively JR, Jacobson SG, Jones K, Jägle H, Janecke AR, Kellner U, Liskova P, Lorenz B, Martorell-Sampol L, Messias A, Meunier I, Belga Ottoni Porto F, Papageorgiou E, Plomp AS, de Ravel TJL, Reiff CM, Renner AB, Rosenberg T, Rudolph G, Salati R, Sener EC, Sieving PA, Stanzial F, Traboulsi EI, Tsang SH, Varsanyi B, Weleber RG, Zobor D, Stingl K, Wissinger B, Kohl S. Comprehensive variant spectrum of the CNGA3 gene in patients affected by achromatopsia. Hum Mutat 2022; 43:832-858. [PMID: 35332618 DOI: 10.1002/humu.24371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 02/23/2022] [Accepted: 03/22/2022] [Indexed: 11/06/2022]
Abstract
Achromatopsia (ACHM) is a congenital cone photoreceptor disorder characterized by impaired color discrimination, low visual acuity, photosensitivity, and nystagmus. To date, six genes have been associated with ACHM (CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, and ATF6), the majority of these being implicated in the cone phototransduction cascade. CNGA3 encodes the CNGA3 subunit of the cyclic nucleotide-gated ion channel in cone photoreceptors and is one of the major disease-associated genes for ACHM. Herein, we provide a comprehensive overview of the CNGA3 variant spectrum in a cohort of 1060 genetically confirmed ACHM patients, 385 (36.3%) of these carrying "likely disease-causing" variants in CNGA3. Compiling our own genetic data with those reported in the literature and in public databases, we further extend the CNGA3 variant spectrum to a total of 316 variants, 244 of which we interpreted as "likely disease-causing" according to ACMG/AMP criteria. We report 48 novel "likely disease-causing" variants, 24 of which are missense substitutions underlining the predominant role of this mutation class in the CNGA3 variant spectrum. In addition, we provide extensive in silico analyses and summarize reported functional data of previously analyzed missense, nonsense and splicing variants to further advance the pathogenicity assessment of the identified variants.
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Affiliation(s)
- Maria Solaki
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Britta Baumann
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Peggy Reuter
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Sten Andreasson
- Department of Ophthalmology, University Hospital Lund, Lund, Sweden
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- CHNO des Quinze-Vingts, Centre de Référence Maladies Rares REFERET, and INSERM-DGOS CIC1423, Paris, France
| | - Carmen Ayuso
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz University Hospital - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Ghassan Balousha
- Department of Pathology and Histology, Faculty of Medicine, Al-Quds University, Eastern Jerusalem, Palestine
| | - Francesco Benedicenti
- Clinical Genetics Service and South Tyrol Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | - David Birch
- Retina Foundation of the Southwest, Dallas, Texas, USA
| | - Pierre Bitoun
- Genetique Medicale, CHU Paris Nord, Hopital Jean Verdier, Bondy Cedex, France
| | | | - Beatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, Montpellier, France
| | - Kari Branham
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, USA
| | - Jaume Català-Mora
- Unitat de Distròfies Hereditàries de Retina Hospital Sant Joan de Déu, Barcelona, Esplugues de Llobregat, Spain
| | - Elfride De Baere
- Department of Biomolecular Medicine, Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Helene Dollfus
- CARGO, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
- U-1112, Inserm, Faculté de Médecine, Université de Strasbourg, Strasbourg, France
| | - Mohammed Falana
- Department of Pathology and Histology, Faculty of Medicine, Al-Quds University, Eastern Jerusalem, Palestine
| | - Roberto Giorda
- Molecular Biology Laboratory, Scientific Institute IRCCS E. Medea, Bosisio Parini, Lecco, Italy
| | - Irina Golovleva
- Department of Medical Biosciences/Medical and Clinical Genetics, University of Umea, Umea, Sweden
| | - Irene Gottlob
- The University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, UK
| | - John R Heckenlively
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, Michigan, USA
| | - Samuel G Jacobson
- Department of Ophthalmology, Perelman School of Medicine, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Kaylie Jones
- Retina Foundation of the Southwest, Dallas, Texas, USA
| | - Herbert Jägle
- Department of Ophthalmology, University of Regensburg, Regensburg, Germany
| | - Andreas R Janecke
- Institute of Human Genetics, Medical University of Innsbruck, Innsbruck, Austria
| | - Ulrich Kellner
- Zentrum für Seltene Netzhauterkrankungen, AugenZentrum Siegburg, MVZ Augenärztliches Diagnostik- und Therapiecentrum Siegburg GmbH, Siegburg, Germany
- RetinaScience, Bonn, 53192, Germany
| | - Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig University Giessen, Giessen, Germany
- Department of Ophthalmology, Universitaetsklinikum Bonn, Bonn, Germany
| | | | - André Messias
- Department of Ophthalmology, Otorhinolaryngology, and Head and Neck Surgery, School of Medicine of Ribeirão Preto, University of São Paulo, Ribeirão Preto, Brazil
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, Montpellier University Hospital, University of Montpellier, Montpellier, France
- Sensgene Care Network, France
| | | | - Eleni Papageorgiou
- Department of Ophthalmology, University Hospital of Larissa, Mezourlo, Larissa, Greece
| | - Astrid S Plomp
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Thomy J L de Ravel
- Centre for Medical Genetics, University Hospital Brussels, Brussels, Belgium
| | | | | | - Thomas Rosenberg
- Department of Ophthalmology, National Eye Clinic, Glostrup Hospital, Glostrup, Denmark
| | - Günther Rudolph
- University Eye Hospital, Ludwig Maximilians University, Munich, Germany
| | - Roberto Salati
- Scientific Institute, IRCCS Eugenio Medea, Pediatric Ophthalmology Unit, Bosisio Parini, Lecco, Italy
| | - E Cumhur Sener
- Strabismus and Pediatric Ophthalmology, Private Practice, Ankara, Turkey
| | - Paul A Sieving
- Center for Ocular Regenerative Therapy, School of Medicine, University of California Davis, Sacramento, USA
| | - Franco Stanzial
- Clinical Genetics Service and South Tyrol Coordination Center for Rare Diseases, Department of Pediatrics, Regional Hospital of Bolzano, Bolzano, Italy
| | - Elias I Traboulsi
- Center for Genetic Eye Diseases, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, Ohio, USA
| | - Stephen H Tsang
- Department of Ophthalmology, Pathology and Cell Biology, College of Physicians and Surgeons, Columbia Stem Cell Initiative, Columbia University, New York City, New York, USA
| | - Balázs Varsanyi
- Department of Ophthalmology, Medical School, University of Pécs and Ganglion Medical Center, Pécs, Pécs, Hungary
| | - Richard G Weleber
- Oregon Health & Science University, Ophthalmic Genetics Service of the Casey Eye Institute, 515 SW Campus Drive, 97239, Portland, Oregon, USA
| | - Ditta Zobor
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Hospital Tübingen, Tübingen, Germany
- Department of Ophthalmology, Semmelweis University Budapest, Budapest, Hungary
| | - Katarina Stingl
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, Tübingen, Germany
- Center for Rare Eye Diseases, University of Tübingen, Tübingen, Germany
| | - Bernd Wissinger
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
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Delineating the Molecular and Phenotypic Spectrum of the CNGA3-Related Cone Photoreceptor Disorder in Pakistani Families. Genes (Basel) 2022; 13:genes13040617. [PMID: 35456423 PMCID: PMC9031457 DOI: 10.3390/genes13040617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/10/2022] [Accepted: 03/21/2022] [Indexed: 11/17/2022] Open
Abstract
Cone photoreceptor dysfunction represents a clinically heterogenous group of disorders characterized by nystagmus, photophobia, reduced central or color vision, and macular dystrophy. Here, we described the molecular findings and clinical manifestations of achromatopsia, a partial or total absence of color vision, co-segregating with three known missense variants of CNGA3 in three large consanguineous Pakistani families. Fundus examination and optical coherence tomography (OCT) imaging revealed myopia, thin retina, retinal pigment epithelial cells loss at fovea/perifovea, and macular atrophy. Combination of Sanger and whole exome sequencing revealed three known homozygous missense variants (c.827A>G, p.(Asn276Ser); c.847C>T, p.(Arg283Trp); c.1279C>T, p.(Arg427Cys)) in CNGA3, the α-subunit of the cyclic nucleotide-gated cation channel in cone photoreceptor cells. All three variants are predicted to replace evolutionary conserved amino acids, and to be pathogenic by specific in silico programs, consistent with the observed altered membrane targeting of CNGA3 in heterologous cells. Insights from our study will facilitate counseling regarding the molecular and phenotypic landscape of CNGA3-related cone dystrophies.
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Michalakis S, Gerhardt M, Rudolph G, Priglinger S, Priglinger C. Achromatopsia: Genetics and Gene Therapy. Mol Diagn Ther 2022; 26:51-59. [PMID: 34860352 PMCID: PMC8766373 DOI: 10.1007/s40291-021-00565-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/02/2021] [Indexed: 01/02/2023]
Abstract
Achromatopsia (ACHM), also known as rod monochromatism or total color blindness, is an autosomal recessively inherited retinal disorder that affects the cones of the retina, the type of photoreceptors responsible for high-acuity daylight vision. ACHM is caused by pathogenic variants in one of six cone photoreceptor-expressed genes. These mutations result in a functional loss and a slow progressive degeneration of cone photoreceptors. The loss of cone photoreceptor function manifests at birth or early in childhood and results in decreased visual acuity, lack of color discrimination, abnormal intolerance to light (photophobia), and rapid involuntary eye movement (nystagmus). Up to 90% of patients with ACHM carry mutations in CNGA3 or CNGB3, which are the genes encoding the alpha and beta subunits of the cone cyclic nucleotide-gated (CNG) channel, respectively. No authorized therapy for ACHM exists, but research activities have intensified over the past decade and have led to several preclinical gene therapy studies that have shown functional and morphological improvements in animal models of ACHM. These encouraging preclinical data helped advance multiple gene therapy programs for CNGA3- and CNGB3-linked ACHM into the clinical phase. Here, we provide an overview of the genetic and molecular basis of ACHM, summarize the gene therapy-related research activities, and provide an outlook for their clinical application.
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Affiliation(s)
- Stylianos Michalakis
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstr. 8, 80336, Munich, Germany.
| | - Maximilian Gerhardt
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstr. 8, 80336, Munich, Germany
| | - Günther Rudolph
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstr. 8, 80336, Munich, Germany
| | - Siegfried Priglinger
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstr. 8, 80336, Munich, Germany
| | - Claudia Priglinger
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstr. 8, 80336, Munich, Germany
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6
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Lowndes R, Molz B, Warriner L, Herbik A, de Best PB, Raz N, Gouws A, Ahmadi K, McLean RJ, Gottlob I, Kohl S, Choritz L, Maguire J, Kanowski M, Käsmann-Kellner B, Wieland I, Banin E, Levin N, Hoffmann MB, Morland AB, Baseler HA. Structural Differences Across Multiple Visual Cortical Regions in the Absence of Cone Function in Congenital Achromatopsia. Front Neurosci 2021; 15:718958. [PMID: 34720857 PMCID: PMC8551799 DOI: 10.3389/fnins.2021.718958] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/16/2021] [Indexed: 11/13/2022] Open
Abstract
Most individuals with congenital achromatopsia (ACHM) carry mutations that affect the retinal phototransduction pathway of cone photoreceptors, fundamental to both high acuity vision and colour perception. As the central fovea is occupied solely by cones, achromats have an absence of retinal input to the visual cortex and a small central area of blindness. Additionally, those with complete ACHM have no colour perception, and colour processing regions of the ventral cortex also lack typical chromatic signals from the cones. This study examined the cortical morphology (grey matter volume, cortical thickness, and cortical surface area) of multiple visual cortical regions in ACHM (n = 15) compared to normally sighted controls (n = 42) to determine the cortical changes that are associated with the retinal characteristics of ACHM. Surface-based morphometry was applied to T1-weighted MRI in atlas-defined early, ventral and dorsal visual regions of interest. Reduced grey matter volume in V1, V2, V3, and V4 was found in ACHM compared to controls, driven by a reduction in cortical surface area as there was no significant reduction in cortical thickness. Cortical surface area (but not thickness) was reduced in a wide range of areas (V1, V2, V3, TO1, V4, and LO1). Reduction in early visual areas with large foveal representations (V1, V2, and V3) suggests that the lack of foveal input to the visual cortex was a major driving factor in morphological changes in ACHM. However, the significant reduction in ventral area V4 coupled with the lack of difference in dorsal areas V3a and V3b suggest that deprivation of chromatic signals to visual cortex in ACHM may also contribute to changes in cortical morphology. This research shows that the congenital lack of cone input to the visual cortex can lead to widespread structural changes across multiple visual areas.
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Affiliation(s)
- Rebecca Lowndes
- Department of Psychology, University of York, York, United Kingdom
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Barbara Molz
- Department of Psychology, University of York, York, United Kingdom
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, Netherlands
| | - Lucy Warriner
- Department of Psychology, University of York, York, United Kingdom
| | - Anne Herbik
- Department of Ophthalmology, University Hospital, Otto von Guericke University, Magdeburg, Germany
| | - Pieter B. de Best
- MRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Noa Raz
- MRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Andre Gouws
- York Neuroimaging Centre, Department of Psychology, University of York, York, United Kingdom
| | - Khazar Ahmadi
- Department of Ophthalmology, University Hospital, Otto von Guericke University, Magdeburg, Germany
| | - Rebecca J. McLean
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tübingen, Tübingen, Germany
| | - Lars Choritz
- Department of Ophthalmology, University Hospital, Otto von Guericke University, Magdeburg, Germany
| | - John Maguire
- School of Optometry and Vision Sciences, University of Bradford, Bradford, United Kingdom
| | - Martin Kanowski
- Department of Neurology, University Hospital, Otto von Guericke University, Magdeburg, Germany
| | - Barbara Käsmann-Kellner
- Department of Ophthalmology, Saarland University Hospital and Medical Faculty of the Saarland University Hospital, Homburg, Germany
| | - Ilse Wieland
- Department of Molecular Genetics, Institute for Human Genetics, University Hospital, Otto von Guericke University, Magdeburg, Germany
| | - Eyal Banin
- Degenerative Diseases of the Retina Unit, Department of Ophthalmology, Hadassah Medical Center, Jerusalem, Israel
| | - Netta Levin
- MRI Unit, Department of Neurology, Hadassah Medical Center, Jerusalem, Israel
| | - Michael B. Hoffmann
- Department of Ophthalmology, University Hospital, Otto von Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
| | - Antony B. Morland
- Department of Psychology, University of York, York, United Kingdom
- York Biomedical Research Institute, University of York, York, United Kingdom
| | - Heidi A. Baseler
- Department of Psychology, University of York, York, United Kingdom
- York Biomedical Research Institute, University of York, York, United Kingdom
- Hull York Medical School, University of York, York, United Kingdom
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Kohl S, Baumann B, Dassie F, Mayer AK, Solaki M, Reuter P, Kühlewein L, Wissinger B, Maffei P. Paternal Uniparental Isodisomy of Chromosome 2 in a Patient with CNGA3-Associated Autosomal Recessive Achromatopsia. Int J Mol Sci 2021; 22:7842. [PMID: 34360608 PMCID: PMC8346044 DOI: 10.3390/ijms22157842] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/13/2021] [Accepted: 07/21/2021] [Indexed: 01/18/2023] Open
Abstract
Achromatopsia (ACHM) is a rare autosomal recessively inherited retinal disease characterized by congenital photophobia, nystagmus, low visual acuity, and absence of color vision. ACHM is genetically heterogeneous and can be caused by biallelic mutations in the genes CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, or ATF6. We undertook molecular genetic analysis in a single female patient with a clinical diagnosis of ACHM and identified the homozygous variant c.778G>C;p.(D260H) in the CNGA3 gene. While segregation analysis in the father, as expected, identified the CNGA3 variant in a heterozygous state, it could not be displayed in the mother. Microsatellite marker analysis provided evidence that the homozygosity of the CNGA3 variant is due to partial or complete paternal uniparental isodisomy (UPD) of chromosome 2 in the patient. Apart from the ACHM phenotype, the patient was clinically unsuspicious and healthy. This is one of few examples proving UPD as the underlying mechanism for the clinical manifestation of a recessive mutation in a patient with inherited retinal disease. It also highlights the importance of segregation analysis in both parents of a given patient or especially in cases of homozygous recessive mutations, as UPD has significant implications for genetic counseling with a very low recurrence risk assessment in such families.
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Affiliation(s)
- Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Britta Baumann
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Francesca Dassie
- Department of Medicine (DIMED), University of Padua, 35121 Padua, Italy; (F.D.); (P.M.)
| | - Anja K. Mayer
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Maria Solaki
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Peggy Reuter
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Laura Kühlewein
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
- Centre for Ophthalmology, University Eye Hospital, University Tübingen, 72076 Tübingen, Germany
| | - Bernd Wissinger
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, 72076 Tübingen, Germany; (B.B.); (A.K.M.); (M.S.); (P.R.); (L.K.); (B.W.)
| | - Pietro Maffei
- Department of Medicine (DIMED), University of Padua, 35121 Padua, Italy; (F.D.); (P.M.)
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Sensing through Non-Sensing Ocular Ion Channels. Int J Mol Sci 2020; 21:ijms21186925. [PMID: 32967234 PMCID: PMC7554890 DOI: 10.3390/ijms21186925] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/12/2022] Open
Abstract
Ion channels are membrane-spanning integral proteins expressed in multiple organs, including the eye. In the eye, ion channels are involved in various physiological processes, like signal transmission and visual processing. A wide range of mutations have been reported in the corresponding genes and their interacting subunit coding genes, which contribute significantly to an array of blindness, termed ocular channelopathies. These mutations result in either a loss- or gain-of channel functions affecting the structure, assembly, trafficking, and localization of channel proteins. A dominant-negative effect is caused in a few channels formed by the assembly of several subunits that exist as homo- or heteromeric proteins. Here, we review the role of different mutations in switching a “sensing” ion channel to “non-sensing,” leading to ocular channelopathies like Leber’s congenital amaurosis 16 (LCA16), cone dystrophy, congenital stationary night blindness (CSNB), achromatopsia, bestrophinopathies, retinitis pigmentosa, etc. We also discuss the various in vitro and in vivo disease models available to investigate the impact of mutations on channel properties, to dissect the disease mechanism, and understand the pathophysiology. Innovating the potential pharmacological and therapeutic approaches and their efficient delivery to the eye for reversing a “non-sensing” channel to “sensing” would be life-changing.
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9
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Yang F, Ma H, Butler MR, Ding XQ. Potential contribution of ryanodine receptor 2 upregulation to cGMP/PKG signaling-induced cone degeneration in cyclic nucleotide-gated channel deficiency. FASEB J 2020; 34:6335-6350. [PMID: 32173907 PMCID: PMC7299158 DOI: 10.1096/fj.201901951rr] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 02/01/2020] [Accepted: 03/01/2020] [Indexed: 12/28/2022]
Abstract
Photoreceptor cyclic nucleotide-gated (CNG) channels regulate Ca2+ influx in rod and cone photoreceptors. Mutations in cone CNG channel subunits CNGA3 and CNGB3 are associated with achromatopsia and cone dystrophies. Mice lacking functional cone CNG channel show endoplasmic reticulum (ER) stress-associated cone degeneration. The elevated cyclic guanosine monophosphate (cGMP)/cGMP-dependent protein kinase (PKG) signaling and upregulation of the ER Ca2+ channel ryanodine receptor 2 (RyR2) have been implicated in cone degeneration. This work investigates the potential contribution of RyR2 to cGMP/PKG signaling-induced ER stress and cone degeneration. We demonstrated that the expression and activity of RyR2 were highly regulated by cGMP/PKG signaling. Depletion of cGMP by deleting retinal guanylate cyclase 1 or inhibition of PKG using chemical inhibitors suppressed the upregulation of RyR2 in CNG channel deficiency. Depletion of cGMP or deletion of Ryr2 equivalently inhibited unfolded protein response/ER stress, activation of the CCAAT-enhancer-binding protein homologous protein, and activation of the cyclic adenosine monophosphate response element-binding protein, leading to early-onset cone protection. In addition, treatment with cGMP significantly enhanced Ryr2 expression in cultured photoreceptor-derived Weri-Rb1 cells. Findings from this work demonstrate the regulation of cGMP/PKG signaling on RyR2 in the retina and support the role of RyR2 upregulation in cGMP/PKG signaling-induced ER stress and photoreceptor degeneration.
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Affiliation(s)
- Fan Yang
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Hongwei Ma
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Michael R. Butler
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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10
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Tobias P, Philipp SI, Stylianos M, Martin B, Barbara W, Felix R, Alexander OG, Eberhart Z, Marius U, Birgit K, Sven K, Ulrich BSK, Dominik FM, Bartz-Schmidt KU, Bolz S, Fischer D, Kohl S, Kühlewein L, Mühlfriedel R, Neubauer J, Ochakovski A, Paquet-Durand F, Seeliger M, Sothilingam V, Ueffing M, Weisschuh N, Wissinger B, Zhour A, Zobor D, Zrenner E, Biel M, Michalakis S, Schön C, Kahle N, Peters T, Wilhelm B, Tsang S, Glöckner CJ. Safety and Toxicology of Ocular Gene Therapy with Recombinant AAV Vector rAAV.hCNGA3 in Nonhuman Primates. HUM GENE THER CL DEV 2019; 30:50-56. [DOI: 10.1089/humc.2018.188] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Peters Tobias
- University Eye Hospital Tübingen, University of Tübingen, Tübingen, Germany
- STZ Eyetrial, University of Tübingen, Tübingen, Germany
| | | | - Michalakis Stylianos
- Center for Integrated Protein Science Munich, Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of Munich, Munich, Germany
| | - Biel Martin
- Center for Integrated Protein Science Munich, Department of Pharmacy – Center for Drug Research, Ludwig Maximilian University of Munich, Munich, Germany
| | | | - Reichel Felix
- University Eye Hospital Tübingen, University of Tübingen, Tübingen, Germany
| | | | - Zrenner Eberhart
- Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Ueffing Marius
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | | | - Korte Sven
- Covance Preclinical Services GmbH, Münster, Germany
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11
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Sun W, Zhang Q. Diseases associated with mutations in CNGA3: Genotype-phenotype correlation and diagnostic guideline. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2018; 161:1-27. [PMID: 30711023 DOI: 10.1016/bs.pmbts.2018.10.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Along with the molecular and functional characterization of CNGA3, knowledge about diseases associated with CNGA3 mutations has made great progress. So far, CNGA3 mutations are not only one of the most common causes of achromatopsia and cone dystrophy or cone-rod dystrophy but also one of the most commonly mutated genes among various forms of retinopathy. Understanding the clinical characteristics of CNGA3-associated retinal diseases may help clinical practice of infants or children with related diseases. Recognizing the importance of CNGA3 in inherited retinal diseases may enhance related research in searching for functional restoration or repair of CNGA3 defects.
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Affiliation(s)
- Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
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12
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Täger J, Kohl S, Birch DG, Wheaton DKH, Wissinger B, Reuter P. An early nonsense mutation facilitates the expression of a short isoform of CNGA3 by alternative translation initiation. Exp Eye Res 2018; 171:48-53. [PMID: 29499183 DOI: 10.1016/j.exer.2018.02.027] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 02/26/2018] [Accepted: 02/26/2018] [Indexed: 11/24/2022]
Abstract
The cyclic nucleotide-gated (CNG) channel - composed of CNGA3 and CNGB3 subunits - mediates the influx of cations in cone photoreceptors after light stimulation and thus is a key element in cone phototransduction. Mutations in CNGA3 and CNGB3 are associated with achromatopsia, a rare autosomal recessive retinal disorder. Here, we demonstrate that the presence of an early nonsense mutation in CNGA3 induces the usage of a downstream alternative translation initiation site giving rise to a short CNGA3 isoform. The expression of this short isoform was verified by Western blot analysis and DAB staining of HEK293 cells and cone photoreceptor-like 661W cells expressing CNGA3-GST fusion constructs. Functionality of the short isoform was confirmed by a cellular calcium influx assay. Furthermore, patients carrying an early nonsense mutation were analyzed for residual cone photoreceptor function in order to identify a potential role of the short isoform to modify the clinical outcome in achromatopsia patients. Yet the results suggest that the short isoform is not able to compensate for the loss of the long isoform leaving the biological role of this variant unclear.
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Affiliation(s)
- Joachim Täger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany; Graduate School of Cellular and Molecular Neuroscience, University of Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | | | | | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
| | - Peggy Reuter
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany.
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13
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Maguire J, McKibbin M, Khan K, Kohl S, Ali M, McKeefry D. CNGB3 mutations cause severe rod dysfunction. Ophthalmic Genet 2017; 39:108-114. [PMID: 28929832 DOI: 10.1080/13816810.2017.1368087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Congenital achromatopsia or rod monochromatism is a rare autosomal recessive condition defined by a severe loss of cone photoreceptor function in which rods purportedly retain normal or near-to-normal function. This report describes the results of electroretinography in two siblings with CNGB3-associated achromatopsia. METHODS Full field light- and dark-adapted electroretinograms (ERGs) were recorded using standard protocols detailed by the International Society for Clinical Electrophysiology of Vision (ISCEV). We also examined rod-mediated ERGs using series of stimuli that varied over a 6 log unit range of retinal illuminances (-1.9-3.5 log scotopic trolands). RESULTS Dark-adapted ERGs in achromatopsia patients exhibited severely reduced b-wave amplitudes with abnormal b:a ratios (1.3 and 0.6). In comparison, the reduction in a-wave amplitude was less marked. The rod-mediated ERG took on an electronegative appearance at high-stimulus illuminances. CONCLUSION Although the defect that causes achromatopsia is primarily in the cone photoreceptors, our results reveal an accompanying disruption of rod function that is more severe than has previously been reported. The differential effects on the b-wave relative to the a-wave points to an inner-retinal locus for the disruption of rod function in these patients.
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Affiliation(s)
- J Maguire
- a School of Optometry and Vision Sciences , University of Bradford , Bradford , West Yorkshire , UK
| | - M McKibbin
- b Department of Ophthalmology , St. James's University Teaching Hospital , Leeds , UK
| | - K Khan
- b Department of Ophthalmology , St. James's University Teaching Hospital , Leeds , UK
| | - S Kohl
- c Molecular Genetics Laboratory, Institute of Ophthalmic Research, Centre of Ophthalmology , University Clinics Tubingen , Tubingen , Germany
| | - M Ali
- d Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical Sciences , University of Leeds , Leeds , UK
| | - D McKeefry
- a School of Optometry and Vision Sciences , University of Bradford , Bradford , West Yorkshire , UK
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14
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Ye GJ, Budzynski E, Sonnentag P, Nork TM, Sheibani N, Gurel Z, Boye SL, Peterson JJ, Boye SE, Hauswirth WW, Chulay JD. Cone-Specific Promoters for Gene Therapy of Achromatopsia and Other Retinal Diseases. Hum Gene Ther 2016; 27:72-82. [PMID: 26603570 DOI: 10.1089/hum.2015.130] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Adeno-associated viral (AAV) vectors containing cone-specific promoters have rescued cone photoreceptor function in mouse and dog models of achromatopsia, but cone-specific promoters have not been optimized for use in primates. Using AAV vectors administered by subretinal injection, we evaluated a series of promoters based on the human L-opsin promoter, or a chimeric human cone transducin promoter, for their ability to drive gene expression of green fluorescent protein (GFP) in mice and nonhuman primates. Each of these promoters directed high-level GFP expression in mouse photoreceptors. In primates, subretinal injection of an AAV-GFP vector containing a 1.7-kb L-opsin promoter (PR1.7) achieved strong and specific GFP expression in all cone photoreceptors and was more efficient than a vector containing the 2.1-kb L-opsin promoter that was used in AAV vectors that rescued cone function in mouse and dog models of achromatopsia. A chimeric cone transducin promoter that directed strong GFP expression in mouse and dog cone photoreceptors was unable to drive GFP expression in primate cones. An AAV vector expressing a human CNGB3 gene driven by the PR1.7 promoter rescued cone function in the mouse model of achromatopsia. These results have informed the design of an AAV vector for treatment of patients with achromatopsia.
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Affiliation(s)
- Guo-Jie Ye
- 1 Applied Genetic Technologies Corporation , Alachua, Florida
| | | | | | - T Michael Nork
- 3 University of Wisconsin-Madison , Madison, Wisconsin
- 4 OSOD (Ocular Services On Demand), LLC , Madison, Wisconsin
| | - Nader Sheibani
- 3 University of Wisconsin-Madison , Madison, Wisconsin
- 4 OSOD (Ocular Services On Demand), LLC , Madison, Wisconsin
| | - Zafer Gurel
- 3 University of Wisconsin-Madison , Madison, Wisconsin
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15
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Kuniyoshi K, Muraki-Oda S, Ueyama H, Toyoda F, Sakuramoto H, Ogita H, Irifune M, Yamamoto S, Nakao A, Tsunoda K, Iwata T, Ohji M, Shimomura Y. Novel mutations in the gene for α-subunit of retinal cone cyclic nucleotide-gated channels in a Japanese patient with congenital achromatopsia. Jpn J Ophthalmol 2016; 60:187-97. [PMID: 27040408 DOI: 10.1007/s10384-016-0424-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 12/22/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE To present the characteristics and pathology of a patient with congenital achromatopsia. PATIENT AND METHODS The patient was a 22-year-old Japanese woman who was 8 years old when she first visited our clinic. Comprehensive ophthalmic examinations including visual acuity measurements, perimetry, optical coherence tomography (OCT), fundus autofluorescence (FAF) imaging, electroretinography (ERG), and color vision tests were performed. Her genomic DNA was used as the template for the amplification of exons of five candidate genes for achromatopsia; CNGA3, CNGB3, GNAT2, PDE6C, and PDE6H, and the amplified products were sequenced. A missense mutation, found in the CNGA3, was studied both electrophysiologically and biochemically. RESULTS Her phenotype was typical of congenital complete achromatopsia. She was followed for 14 years, and her vision and fundus findings were stable. However, the scotopic ERG b-waves at age 22 were smaller than those at age 8, and her FAF images showed increased autofluorescence in both maculae. Genetic examinations revealed combined heterozygous mutations of c.997_998delGA and p.M424V in the CNGA3 gene. The homomeric channel consisting of the CNGA3 subunit with the p.M424V mutation had a weak cGMP-activated current in patch-clamp recordings. In heterologous expression analyses, the expression at the cell surface of the mutant CNGA3 subunit was about 28 % of the wild type. CONCLUSIONS The two novel mutations found in the CNGA3 gene, c.997_998delGA and p.M424V, can cause complete achromatopsia. The vision of the patient was stationary until the third decade of life although the FAF was altered at the age of 22 years.
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Affiliation(s)
- Kazuki Kuniyoshi
- Department of Ophthalmology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8911, Japan.
| | - Sanae Muraki-Oda
- Department of Ophthalmology, Shiga University of Medical Science, Otsu, Japan
| | - Hisao Ueyama
- Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Futoshi Toyoda
- Department of Physiology, Shiga University of Medical Science, Otsu, Japan
| | - Hiroyuki Sakuramoto
- Department of Ophthalmology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8911, Japan
| | - Hisakazu Ogita
- Department of Biochemistry and Molecular Biology, Shiga University of Medical Science, Otsu, Japan
| | - Motohiro Irifune
- Department of Ophthalmology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8911, Japan
- Irifune Eye Clinic, Izumi, Japan
| | - Shuji Yamamoto
- Jin Eye Clinic, Nishinomiya, Japan
- Department of Ophthalmology, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Akira Nakao
- Department of Ophthalmology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8911, Japan
| | - Kazushige Tsunoda
- Laboratory of Visual Physiology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Masahito Ohji
- Department of Ophthalmology, Shiga University of Medical Science, Otsu, Japan
| | - Yoshikazu Shimomura
- Department of Ophthalmology, Kinki University Faculty of Medicine, 377-2 Ohno-higashi, Osaka-Sayama, Osaka, 589-8911, Japan
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16
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Banin E, Gootwine E, Obolensky A, Ezra-Elia R, Ejzenberg A, Zelinger L, Honig H, Rosov A, Yamin E, Sharon D, Averbukh E, Hauswirth WW, Ofri R. Gene Augmentation Therapy Restores Retinal Function and Visual Behavior in a Sheep Model of CNGA3 Achromatopsia. Mol Ther 2015; 23:1423-33. [PMID: 26087757 DOI: 10.1038/mt.2015.114] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 06/05/2015] [Indexed: 12/15/2022] Open
Abstract
Achromatopsia is a hereditary form of day blindness caused by cone photoreceptor dysfunction. Affected patients suffer from congenital color blindness, photosensitivity, and low visual acuity. Mutations in the CNGA3 gene are a major cause of achromatopsia, and a sheep model of this disease was recently characterized by our group. Here, we report that unilateral subretinal delivery of an adeno-associated virus serotype 5 (AAV5) vector carrying either the mouse or the human intact CNGA3 gene under the control of the red/green opsin promoter results in long-term recovery of visual function in CNGA3-mutant sheep. Treated animals demonstrated shorter maze passage times and a reduced number of collisions with obstacles compared with their pretreatment status, with values close to those of unaffected sheep. This effect was abolished when the treated eye was patched. Electroretinography (ERG) showed marked improvement in cone function. Retinal expression of the transfected human and mouse CNGA3 genes at the mRNA level was shown by polymerase chain reaction (PCR), and cone-specific expression of CNGA3 protein was demonstrated by immunohistochemisrty. The rescue effect has so far been maintained for over 3 years in the first-treated animals, with no obvious ocular or systemic side effects. The results support future application of subretinal AAV5-mediated gene-augmentation therapy in CNGA3 achromatopsia patients.
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Affiliation(s)
- Eyal Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Elisha Gootwine
- Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Alexey Obolensky
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Raaya Ezra-Elia
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Ayala Ejzenberg
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Lina Zelinger
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Hen Honig
- Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Alexander Rosov
- Agricultural Research Organization, The Volcani Center, Bet Dagan, Israel
| | - Esther Yamin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Edward Averbukh
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, Florida, USA
| | - Ron Ofri
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
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