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Yang Z, Yan L, Zhang W, Qi J, An W, Yao K. Dyschromatopsia: a comprehensive analysis of mechanisms and cutting-edge treatments for color vision deficiency. Front Neurosci 2024; 18:1265630. [PMID: 38298913 PMCID: PMC10828017 DOI: 10.3389/fnins.2024.1265630] [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: 07/23/2023] [Accepted: 01/02/2024] [Indexed: 02/02/2024] Open
Abstract
Color blindness is a retinal disease that mainly manifests as a color vision disorder, characterized by achromatopsia, red-green color blindness, and blue-yellow color blindness. With the development of technology and progress in theory, extensive research has been conducted on the genetic basis of color blindness, and various approaches have been explored for its treatment. This article aims to provide a comprehensive review of recent advances in understanding the pathological mechanism, clinical symptoms, and treatment options for color blindness. Additionally, we discuss the various treatment approaches that have been developed to address color blindness, including gene therapy, pharmacological interventions, and visual aids. Furthermore, we highlight the promising results from clinical trials of these treatments, as well as the ongoing challenges that must be addressed to achieve effective and long-lasting therapeutic outcomes. Overall, this review provides valuable insights into the current state of research on color blindness, with the intention of informing further investigation and development of effective treatments for this disease.
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Affiliation(s)
- Zihao Yang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Lin Yan
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenliang Zhang
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Jia Qi
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Wenjing An
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
| | - Kai Yao
- Institute of Visual Neuroscience and Stem Cell Engineering, Wuhan University of Science and Technology, Wuhan, China
- College of Life Sciences and Health, Wuhan University of Science and Technology, Wuhan, China
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2
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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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3
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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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Georgiou M, Singh N, Kane T, Zaman S, Hirji N, Aboshiha J, Kumaran N, Kalitzeos A, Carroll J, Weleber RG, Michaelides M. Long-Term Investigation of Retinal Function in Patients with Achromatopsia. Invest Ophthalmol Vis Sci 2021; 61:38. [PMID: 32960951 PMCID: PMC7509756 DOI: 10.1167/iovs.61.11.38] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To investigate the long-term natural history of retinal function of achromatopsia (ACHM). Methods Subjects with molecularly confirmed ACHM were recruited in a prospective cohort study of mesopic microperimetry. Coefficient of repeatability and intraclass correlation coefficient (ICC) of mean sensitivity (MS) were calculated. Best-corrected visual acuity (BCVA), bivariate contour ellipse area (BCEA), contrast sensitivity (CS), MS, total volume (VTOT), and central field volume (V5°) from volumetric and topographic analyses were acquired. Correlation of functional parameters with structural findings from optical coherence tomography (OCT) was performed. Results Eighteen subjects were recruited. Mean follow-up was 7.2 years. The MS test–retest repeatability coefficient was 1.65 decibels (dB), and the ICC was 0.973 (95% confidence interval, 0.837–0.98). Mean MS was similar for right and left eyes (16.97dB and 17.14dB, respectively). A negative significant correlation between logMAR BCVA and the retinal sensitivity indices (MS, VTOT, V5°) was found. A significant negative correlation between logCS and MS, VTOT, and V5° was also observed. BCVA and BCEA improved during follow-up. Mean CS, MS, VTOT, and V5° at final follow-up were similar to baseline. MS was similar between CNGA3- and CNGB3-ACHM. Patients with and without the presence of a foveal ellipsoid zone on OCT had similar MS (16.64 dB and 17.17 dB, respectively). Conclusions We demonstrate a highly reproducible assessment of MS. Retinal function including MS, volumetric indices, and CS are stable in ACHM. Improvement of fixation stability and small changes of BCVA over time may be part of the natural history of the disease.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Navjit Singh
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Thomas Kane
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Serena Zaman
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Nashila Hirji
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Jonathan Aboshiha
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Neruban Kumaran
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Joseph Carroll
- Department of Ophthalmology & Visual Sciences, Medical College of Wisconsin, Wauwatosa, Wisconsin, United States
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
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Brunetti-Pierri R, Karali M, Melillo P, Di Iorio V, De Benedictis A, Iaccarino G, Testa F, Banfi S, Simonelli F. Clinical and Molecular Characterization of Achromatopsia Patients: A Longitudinal Study. Int J Mol Sci 2021; 22:1681. [PMID: 33562422 PMCID: PMC7914547 DOI: 10.3390/ijms22041681] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 01/28/2021] [Accepted: 02/03/2021] [Indexed: 02/08/2023] Open
Abstract
Achromatopsia (ACHM) is a rare genetic disorder of infantile onset affecting cone photoreceptors. To determine the extent of progressive retinal changes in achromatopsia, we performed a detailed longitudinal phenotyping and genetic characterization of an Italian cohort comprising 21 ACHM patients (17 unrelated families). Molecular genetic testing identified biallelic pathogenic mutations in known ACHM genes, including four novel variants. At baseline, the patients presented a reduced best corrected visual acuity (BCVA), reduced macular sensitivity (MS), normal dark-adapted electroretinogram (ERG) responses and undetectable or severely reduced light-adapted ERG. The longitudinal analysis of 16 patients (mean follow-up: 5.4 ± 1.0 years) showed a significant decline of BCVA (0.012 logMAR/year) and MS (-0.16 dB/year). Light-adapted and flicker ERG responses decreased below noise level in three and two patients, respectively. Only two patients (12.5%) progressed to a worst OCT grading during the follow-up. Our findings corroborate the notion that ACHM is a progressive disease in terms of BCVA, MS and ERG responses, and affects slowly the structural integrity of the retina. These observations can serve towards the development of guidelines for patient selection and intervention timing in forthcoming gene replacement therapies.
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Affiliation(s)
- Raffaella Brunetti-Pierri
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
| | - Marianthi Karali
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy;
| | - Paolo Melillo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
| | - Valentina Di Iorio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
| | - Antonella De Benedictis
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
| | - Gennarfrancesco Iaccarino
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy;
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania “Luigi Vanvitelli”, via Luigi De Crecchio 7, 80138 Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania “Luigi Vanvitelli”, via Pansini 5, 80131 Naples, Italy; (R.B.-P.); (M.K.); (P.M.); (V.D.I.); (A.D.B.); (G.I.); (F.T.)
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6
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Koch M, Scheel C, Ma H, Yang F, Stadlmeier M, Glück AF, Murenu E, Traube FR, Carell T, Biel M, Ding XQ, Michalakis S. The cGMP-Dependent Protein Kinase 2 Contributes to Cone Photoreceptor Degeneration in the Cnga3-Deficient Mouse Model of Achromatopsia. Int J Mol Sci 2020; 22:E52. [PMID: 33374621 PMCID: PMC7793084 DOI: 10.3390/ijms22010052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/18/2020] [Accepted: 12/19/2020] [Indexed: 12/21/2022] Open
Abstract
Mutations in the CNGA3 gene, which encodes the A subunit of the cyclic guanosine monophosphate (cGMP)-gated cation channel in cone photoreceptor outer segments, cause total colour blindness, also referred to as achromatopsia. Cones lacking this channel protein are non-functional, accumulate high levels of the second messenger cGMP and degenerate over time after induction of ER stress. The cell death mechanisms that lead to loss of affected cones are only partially understood. Here, we explored the disease mechanisms in the Cnga3 knockout (KO) mouse model of achromatopsia. We found that another important effector of cGMP, the cGMP-dependent protein kinase 2 (Prkg2) is crucially involved in cGMP cytotoxicity of cones in Cnga3 KO mice. Virus-mediated knockdown or genetic ablation of Prkg2 in Cnga3 KO mice counteracted degeneration and preserved the number of cones. Analysis of markers of endoplasmic reticulum stress and unfolded protein response confirmed that induction of these processes in Cnga3 KO cones also depends on Prkg2. In conclusion, we identified Prkg2 as a novel key mediator of cone photoreceptor degeneration in achromatopsia. Our data suggest that this cGMP mediator could be a novel pharmacological target for future neuroprotective therapies.
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Affiliation(s)
- Mirja Koch
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.K.); (C.S.); (E.M.); (M.B.)
| | - Constanze Scheel
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.K.); (C.S.); (E.M.); (M.B.)
| | - Hongwei Ma
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (H.M.); (F.Y.); (X.-Q.D.)
| | - Fan Yang
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (H.M.); (F.Y.); (X.-Q.D.)
| | - Michael Stadlmeier
- Department of Chemistry, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.S.); (A.F.G.); (F.R.T.); (T.C.)
| | - Andrea F. Glück
- Department of Chemistry, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.S.); (A.F.G.); (F.R.T.); (T.C.)
| | - Elisa Murenu
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.K.); (C.S.); (E.M.); (M.B.)
- Department of Ophthalmology, Ludwig-Maximilians-University, 80336 Munich, Germany
| | - Franziska R. Traube
- Department of Chemistry, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.S.); (A.F.G.); (F.R.T.); (T.C.)
| | - Thomas Carell
- Department of Chemistry, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.S.); (A.F.G.); (F.R.T.); (T.C.)
| | - Martin Biel
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.K.); (C.S.); (E.M.); (M.B.)
| | - Xi-Qin Ding
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (H.M.); (F.Y.); (X.-Q.D.)
| | - Stylianos Michalakis
- Department of Pharmacy—Center for Drug Research, Ludwig-Maximilians-University, 81377 Munich, Germany; (M.K.); (C.S.); (E.M.); (M.B.)
- Department of Ophthalmology, Ludwig-Maximilians-University, 80336 Munich, Germany
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7
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Jinda W, Tuekprakhon A, Thongnoppakhun W, Limwongse C, Trinavarat A, Atchaneeyasakul LO. Molecular and clinical characterization of Thai patients with achromatopsia: identification of three novel disease-associated variants in the CNGA3 and CNGB3 genes. Int Ophthalmol 2020; 41:121-134. [PMID: 32869108 DOI: 10.1007/s10792-020-01559-2] [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: 05/01/2020] [Accepted: 08/17/2020] [Indexed: 11/24/2022]
Abstract
PURPOSE Achromatopsia (ACHM) is an autosomal recessive cone disorder characterized by pendular nystagmus, photophobia, reduced visual acuity, and partial or total absence of color vision. Mutations in six genes (CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, and ATF6) have been reported in ACHM. There is no information on these disease-associated genes in Thai population. This study aimed to investigate the molecular and clinical characteristics in Thai patients with ACHM. METHODS Seven unrelated Thai patients with ACHM were recruited. Detailed ophthalmologic examination was performed. Polymerase chain reaction (PCR)-coupled single-strand conformation polymorphism (SSCP) screening followed by Sanger sequencing was used to identify sequence variants in all exons and splice junctions of three genes (CNGA3, CNGB3, and GNAT2). The pathogenicity of the detected variants was interpreted. Segregation analysis was performed to determine variant sharing in available family members. RESULTS Four patients displayed different SSCP migration patterns. Sequence analysis revealed a reported pathogenic and a novel disease-associated variant in the CNGA3 gene. For the CNGB3 gene, we found two novel disease-associated variants and a reported variant of uncertain significance (VUS). Segregation analysis confirmed that the variants identified in each patient were present in the heterozygous state in their corresponding family members, which was consistent with an autosomal recessive mode of inheritance. CONCLUSIONS This study demonstrated the first molecular and clinical characterization of ACHM in Thai patients. The identification of disease-associated genes in a specific population leads to a personalized gene therapy benefiting those affected patients.
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Affiliation(s)
- Worapoj Jinda
- Division of Medical Genetics Research and Laboratory, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Aekkachai Tuekprakhon
- Clinical Molecular Pathology Laboratory, Department of Clinical Pathology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Wanna Thongnoppakhun
- Division of Medical Genetics Research and Laboratory, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Chanin Limwongse
- Division of Medical Genetics Research and Laboratory, Research Department, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand.,Division of Medical Genetics, Department of Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Adisak Trinavarat
- Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand
| | - La-Ongsri Atchaneeyasakul
- Department of Ophthalmology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, 10700, Thailand.
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Yuan S, Qi R, Fang X, Wang X, Zhou L, Sheng X. Two novel PDE6C gene mutations in Chinese family with achromatopsia. Ophthalmic Genet 2020; 41:591-598. [PMID: 32787476 DOI: 10.1080/13816810.2020.1802762] [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: 10/23/2022]
Abstract
Background: Achromatopsia (ACHM) is an inherited retinal disease affecting the cone cell function. To date, six pathogenic genes of ACHM have been identified. However, the diagnostic and therapeutic methods of this disorder remain limited. Herein, to characterize the clinical features and genetic causes of three affected siblings in a Chinese family with ACHM, we used target next-generation sequencing (NGS) and found new pathogenic factors associated with ACHM in this family. Materials and methods: Three patients with ACHM and three healthy family members were included in this study. All participants received comprehensive ophthalmic tests. NGS approach was performed on the patients to determine the causative mutation for this family. The silico analysis was also applied to predict the pathogenesis of identified mutations. Results: Genetic assessments revealed compound heterozygous mutations of the PDE6C gene (c.1413 + 1 G > C, c.305 G > A), carried by all three patients. Both mutations were novel and predicted to be deleterious by six types of online predictive software. The heterozygous PDE6C missense mutation (c.305 G > A) was found from the mother and the heterozygous PDE6C splice site mutation (c.1413 + 1 G > C) was found in the father and all the children. All patients in the family showed typical signs and symptoms of ACHM. Conclusions: We report novel compound heterozygous PDE6C mutations in causing ACHM and further confirm the clinical diagnosis. Our study extends the genotypic spectrums for PDE6C-ACHM and better illustrates its genotype-phenotype correlations, which would help the ACHM patients with better genetic diagnosis, prognosis, and gene treatment.
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Affiliation(s)
- Shiqin Yuan
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities) , Yinchuan, China
| | - Rui Qi
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities) , Yinchuan, China.,Aier Eye Hospital Group, Hubin Aier Eye Hospital , Binzhou, Shangdong, China
| | - Xinhe Fang
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities) , Yinchuan, China
| | - Xiaoguang Wang
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities) , Yinchuan, China
| | - Liang Zhou
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities) , Yinchuan, China
| | - Xunlun Sheng
- Ningxia Clinical Research Center of Blinding Eye Disease, Ningxia Eye Hospital, People Hospital of Ningxia Hui Autonomous Region (First Affiliated Hospital of Northwest University for Nationalities) , Yinchuan, China
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Georgiou M, Singh N, Kane T, Robson AG, Kalitzeos A, Hirji N, Webster AR, Dubra A, Carroll J, Michaelides M. Photoreceptor Structure in GNAT2-Associated Achromatopsia. Invest Ophthalmol Vis Sci 2020; 61:40. [PMID: 32203983 PMCID: PMC7401776 DOI: 10.1167/iovs.61.3.40] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to report GNAT2-associated achromatopsia (GNAT2-ACHM) natural history, characterize photoreceptor mosaic, and determine a therapeutic window for potential intervention. Methods Patients with GNAT2-ACHM were recruited from a single tertiary referral eye center (Moorfields Eye Hospital, London, UK). We performed longitudinal clinical evaluation and ophthalmic examination, and multimodal retinal imaging, including adaptive optics scanning light ophthalmoscopy, quantitative analysis of the cone mosaic, and outer nuclear layer (ONL) thickness, including cone densities evaluation in selected regions of interest and comparison with reported healthy controls. Results All nine subjects (3 women) presented with nystagmus, decreased visual acuity (VA), light sensitivity, and highly variable color vision loss. One patient had normal color vision and better VA. Mean VA was 1.01 (±0.10) logarithms of the minimal angle of resolution (LogMAR) at baseline, and 1.04 (±0.10) LogMAR after a mean follow-up (range) of 7.6 years (1.7−12.8 years). Optical coherence tomography showed preservation of the foveal ellipsoid zone (EZ; n = 8; 88.9%), and EZ disruption (n = 1; 11.1%). Mean ONL thickness (range, ± SD) was 84.72 µm (28.57−113.33, ± 25.46 µm) and 86.47 µm (28.57−113.33, ± 24.65 µm) for right and left eyes, respectively. Mean cone densities (±SD) at 190 µm, 350 µm, and 500 µm from the foveal center, were 48.4 (±24.6), 37.8 (±14.7), and 30.7 (±9.9), ×103 cones/mm2, respectively. Mean cone densities were lower than these of unaffected individuals, but with an overlap. Conclusions The cone mosaic in GNAT2-ACHM is relatively well preserved, potentially allowing for a wide therapeutic window for cone-directed interventions.
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