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Wu J, Li J, Zhang D, Liu H, Li T, Xu P, Zhao Y, Li C, Hu F, Li Q, Zhang S, Wu JH. From onset to blindness: a comprehensive analysis of RPGR-associated X-linked retinopathy in a large cohort in China. J Med Genet 2024:jmg-2024-110088. [PMID: 39153854 DOI: 10.1136/jmg-2024-110088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Accepted: 08/03/2024] [Indexed: 08/19/2024]
Abstract
BACKGROUND Variants in the RPGR are the leading cause of X-linked retinopathies (XLRPs). Further in-depth investigation is needed to understand the natural history. METHODS Review of all case records, molecular genetic testing results, best-corrected visual acuity (BCVA), retinal imaging data (including fundus autofluorescence imaging and optical coherence tomography (OCT)), static visual field (VF) assessments and full-field electroretinogram. RESULTS Genetic testing was conducted on 104 male patients from 89 family pedigrees, identifying 22 novel variants and 1 de novo variant. The initial symptoms appeared in 78.2% of patients at a median age of 5 years. BCVA declined at a mean rate of 0.02 (IQR, 0-0.04) logarithm of the minimum angle of resolution per year, with a gradual, non-linear decrease over the first 40 years. Autofluorescence imaging revealed macular atrophy at a median age of 36.1 (IQR, 29.9-43.2) years. Patients experienced blindness at a median age of 42.5 (IQR, 32.9-45.2) years according to WHO visual impairment categories. OCT analysis showed a mean ellipsoid zone narrowing rate of 23.3 (IQR, -1.04-22.29) µm/month, with an accelerated reduction in the first 40 years (p<0.01). The median age at which ERG no longer detected a waveform was 26.5 (IQR, 20.5-32.8) years. Comparison by variant location indicated faster progression in patients with exon 1-14 variants during the initial two decades, while those with ORF15 variants showed accelerated progression from the third decade. CONCLUSIONS We provide a foundation for determining the treatment window and an objective basis for evaluating the therapeutic efficacy of gene therapy for XLRP.
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Affiliation(s)
- Jiawen Wu
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Junfeng Li
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Daowei Zhang
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Hongli Liu
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Ting Li
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Ping Xu
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Yingke Zhao
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Chenchen Li
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Fangyuan Hu
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Qian Li
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Shenghai Zhang
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
| | - Ji-Hong Wu
- Department of Opthalmology, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai 200000, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai 200000, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai 200000, China
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2
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Georgiou M, Robson AG, Fujinami K, de Guimarães TAC, Fujinami-Yokokawa Y, Daich Varela M, Pontikos N, Kalitzeos A, Mahroo OA, Webster AR, Michaelides M. Phenotyping and genotyping inherited retinal diseases: Molecular genetics, clinical and imaging features, and therapeutics of macular dystrophies, cone and cone-rod dystrophies, rod-cone dystrophies, Leber congenital amaurosis, and cone dysfunction syndromes. Prog Retin Eye Res 2024; 100:101244. [PMID: 38278208 DOI: 10.1016/j.preteyeres.2024.101244] [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: 10/26/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/28/2024]
Abstract
Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population and in children. The scope of this review is to familiarise clinicians and scientists with the current landscape of molecular genetics, clinical phenotype, retinal imaging and therapeutic prospects/completed trials in IRD. Herein we present in a comprehensive and concise manner: (i) macular dystrophies (Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), PRPH2-associated pattern dystrophy, Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)), (ii) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4, KCNV2 and RPGR), (iii) predominant rod or rod-cone dystrophies (retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)), (iv) Leber congenital amaurosis/early-onset severe retinal dystrophy (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (v) cone dysfunction syndromes (achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6), X-linked cone dysfunction with myopia and dichromacy (Bornholm Eye disease; OPN1LW/OPN1MW array), oligocone trichromacy, and blue-cone monochromatism (OPN1LW/OPN1MW array)). Whilst we use the aforementioned classical phenotypic groupings, a key feature of IRD is that it is characterised by tremendous heterogeneity and variable expressivity, with several of the above genes associated with a range of phenotypes.
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Affiliation(s)
- Michalis Georgiou
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| | - Anthony G Robson
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Kaoru Fujinami
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
| | - Thales A C de Guimarães
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Yu Fujinami-Yokokawa
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan; Department of Health Policy and Management, Keio University School of Medicine, Tokyo, Japan.
| | - Malena Daich Varela
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Nikolas Pontikos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Angelos Kalitzeos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Omar A Mahroo
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Section of Ophthalmology, King s College London, St Thomas Hospital Campus, London, United Kingdom; Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, United Kingdom; Department of Translational Ophthalmology, Wills Eye Hospital, Philadelphia, PA, USA.
| | - Andrew R Webster
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
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3
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Park H, Hwang S, Kim SJ. Severe Phenotypic Presentation of RPGR-associated X-linked Retinitis Pigmentosa in Female Carriers: Two Case Reports. KOREAN JOURNAL OF OPHTHALMOLOGY 2024; 38:164-166. [PMID: 38351481 PMCID: PMC11016683 DOI: 10.3341/kjo.2023.0119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 11/22/2023] [Accepted: 01/04/2024] [Indexed: 04/16/2024] Open
Affiliation(s)
- Hansol Park
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul,
Korea
| | - Sungsoon Hwang
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul,
Korea
- Department of Clinical Research Design and Evaluation, Samsung Advanced Institute for Health Sciences and Technology (SAIHST), Sungkyunkwan University, Seoul,
Korea
| | - Sang Jin Kim
- Department of Ophthalmology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul,
Korea
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4
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Wang SW, Igarashi-Yokoi T, Mochida S, Fujinami K, Ohno-Matsui K. PREVALENCE AND CLINICAL FEATURES OF RADIAL FUNDUS AUTOFLUORESCENCE IN HIGH MYOPIC WOMEN. Retina 2024; 44:446-454. [PMID: 37948743 DOI: 10.1097/iae.0000000000003981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 10/21/2023] [Indexed: 11/12/2023]
Abstract
PURPOSE To determine the prevalence and characteristics of radial fundus autofluorescence (FAF) in highly myopic women. METHODS This was a retrospective, observational case study to determine the prevalence of radial FAF in the ultra-widefield FAF images in women. The clinical characteristics of these patients were evaluated. RESULTS Fifteen of 1,935 (0.78%) highly myopic women were found to have radial FAF. Their mean age was 36.6 ± 25.6 years, and their mean best-corrected visual acuity was 0.3 ± 0.42 logMAR units. The mean axial length (AL) was 28.8 ± 2.8 mm. Among the 15 cases, eight did not have pigmentary changes and seven had pigmentary changes in the ultra-widefield FAF images. The women with the pigmentary changes were significantly older ( P = 0.021), had poorer BCVA ( P = 0.001), and had longer ALs ( P = 0.002). The visual fields and electroretinograms were worse in the eyes with pigmentary changes. CONCLUSION The prevalence of radial FAF was 0.78% in women with high myopia. These patients might have mutations in the RPGR or RP2 genes and can develop high myopia and retinitis pigmentosa. Ultra-widefield FAF images should be examined in all highly myopic patients for early detection of radial FAF, and myopia prevention and genetic counseling for possible genetic therapy are recommended.
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Affiliation(s)
- Shih-Wen Wang
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan
- Department of Ophthalmology, Shuang Ho Hospital, Taipei Medical University, Taiwan, ROC
| | - Tae Igarashi-Yokoi
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shiho Mochida
- Department of Ophthalmology, Tokyo Metropolitan Ohkubo Hospital, Tokyo, Japan; and
| | - Kaoru Fujinami
- National Institute of Sensory Organs, National Hospital Organization, Tokyo Medical Center, Tokyo Japan
| | - Kyoko Ohno-Matsui
- Department of Ophthalmology and Visual Science, Tokyo Medical and Dental University, Tokyo, Japan
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5
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Han RC, Taylor LJ, Martinez-Fernandez de la Camara C, Henderson RH, Thompson DA, Cehajic-Kapetanovic J, MacLaren RE. Is RPGR-related retinal dystrophy associated with systemic disease? A case series. Ophthalmic Genet 2023; 44:577-584. [PMID: 36602268 DOI: 10.1080/13816810.2022.2163405] [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: 09/09/2022] [Revised: 11/30/2022] [Accepted: 12/23/2022] [Indexed: 01/06/2023]
Abstract
BACKGROUND Ciliopathies responsible for retinitis pigmentosa can also cause systemic manifestations. RPGR is a ciliary gene and pathogenic variants in RPGR cause a retinal ciliopathy, the commonest cause of X-linked recessive retinitis pigmentosa. The RPGR protein interacts with numerous other ciliary proteins present in the transition zone of both motile and sensory cilia, and may play an important role in regulating ciliary protein transport. There has been a growing, putative association of RPGR variants with systemic ciliopathies: mainly sino-respiratory infections and primary ciliary dyskinesia. MATERIALS AND METHODS Retrospective case series of patients with RPGR-RP presenting to Oxford Eye Hospital with systemic disease. RESULTS We report three children with RPGR-related rod-cone dystrophy, all of whom have mutations in the N-terminus of RPGR. Two cases co-presented with confirmed diagnoses of primary ciliary dyskinesia and one case with multiple sino-respiratory symptoms strongly suggestive of primary ciliary dyskinesia. These and all previously reported RPGR co-pathologies relate to ciliopathies and have no other systemic associations. CONCLUSIONS The link between RPGR variants and a systemic ciliopathy remains plausible, but currently unproven.
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Affiliation(s)
- Ruofan Connie Han
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Laura J Taylor
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Robert H Henderson
- Department of Ophthalmology, Great Ormond Street Children's Hospital, London, UK
| | - Dorothy A Thompson
- Department of Ophthalmology, Great Ormond Street Children's Hospital, London, UK
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK
| | - Jasmina Cehajic-Kapetanovic
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Robert E MacLaren
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
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6
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Awadh Hashem S, Georgiou M, Ali RR, Michaelides M. RPGR-Related Retinopathy: Clinical Features, Molecular Genetics, and Gene Replacement Therapy. Cold Spring Harb Perspect Med 2023; 13:a041280. [PMID: 37188525 PMCID: PMC10626266 DOI: 10.1101/cshperspect.a041280] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Retinitis pigmentosa GTPase regulator (RPGR) gene variants are the predominant cause of X-linked retinitis pigmentosa (XLRP) and a common cause of cone-rod dystrophy (CORD). XLRP presents as early as the first decade of life, with impaired night vision and constriction of peripheral visual field and rapid progression, eventually leading to blindness. In this review, we present RPGR gene structure and function, molecular genetics, animal models, RPGR-associated phenotypes and highlight emerging potential treatments such as gene-replacement therapy.
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Affiliation(s)
- Shaima Awadh Hashem
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, United Kingdom
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, United Kingdom
- Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
| | - Robin R Ali
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, United Kingdom
- Centre for Cell and Gene Therapy, King's College London, London WC2R 2LS, United Kingdom
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, United Kingdom
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7
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Lee HW, Lee EK. Asymmetric presentation with a novel RP2 gene mutation in X-Linked retinitis pigmentosa: a case report. BMC Ophthalmol 2023; 23:221. [PMID: 37198560 DOI: 10.1186/s12886-023-02968-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 05/09/2023] [Indexed: 05/19/2023] Open
Abstract
BACKGROUND We present the detailed multimodal imaging analysis in a case of X-linked retinitis pigmentosa (XLRP) exhibiting a markedly asymmetric presentation with a novel RP2 mutation. CASE PRESENTATION A 25-year-old woman complained of decreased vision in the right eye as well as night blindness. Her visual acuity was 20/100 (OD) and 20/20 (OS). Fundus examination revealed bone spicule pigmentation with tessellated changes in the fundus within the posterior pole. Optical coherence tomography (OCT) showed generalized disruption of foveal microstructures in the OD. No abnormal findings were identified, but localized ellipsoid zone band losses were observed on OCT in the OS. Fundus autofluorescence revealed multiple patchy hypo-autofluorescent lesions in the OD and a tapetal-like radial reflex against a dark background in the OS. Fluorescein angiography and OCT angiography revealed diffuse mottled hyperfluorescence with reduced retinal vessel density in the OD and no evidence of vascular compromise in the OS. Goldmann perimetry demonstrated a constricted visual field, and electrophysiological assessment revealed an extinguished rod response and a severely impaired cone response in the OD. Molecular genetic tests via next-generation sequencing revealed the pathogenic variant to be a heterozygous frameshift mutation in RP2 (RP2, p.Glu269Glyfs*7), resulting in premature termination of the protein. CONCLUSIONS Random X-inactivation may be attributed to interocular differences in the severity of XLRP in female carriers. A novel frameshift mutation in the RP2 gene and a comprehensive phenotypic evaluation in the current study may broaden the spectrum of the disease in XLRP carriers.
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Affiliation(s)
- Hyun Woo Lee
- Pre-medical Program, Seoul National University College of Medicine, Seoul, Korea
| | - Eun Kyoung Lee
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Hospital, #101, Daehak-ro, Jongno-gu, Seoul, Republic of Korea.
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8
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Koller S, Beltraminelli T, Maggi J, Wlodarczyk A, Feil S, Baehr L, Gerth-Kahlert C, Menghini M, Berger W. Functional Analysis of a Novel, Non-Canonical RPGR Splice Variant Causing X-Linked Retinitis Pigmentosa. Genes (Basel) 2023; 14:genes14040934. [PMID: 37107692 PMCID: PMC10137330 DOI: 10.3390/genes14040934] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/05/2023] [Accepted: 04/12/2023] [Indexed: 04/29/2023] Open
Abstract
X-linked retinitis pigmentosa (XLRP) caused by mutations in the RPGR gene is one of the most severe forms of RP due to its early onset and intractable progression. Most cases have been associated with genetic variants within the purine-rich exon ORF15 region of this gene. RPGR retinal gene therapy is currently being investigated in several clinical trials. Therefore, it is crucial to report and functionally characterize (all novel) potentially pathogenic DNA sequence variants. Whole-exome sequencing (WES) was performed for the index patient. The splicing effects of a non-canonical splice variant were tested on cDNA from whole blood and a minigene assay. WES revealed a rare, non-canonical splice site variant predicted to disrupt the wildtype splice acceptor and create a novel acceptor site 8 nucleotides upstream of RPGR exon 12. Reverse-transcription PCR analyses confirmed the disruption of the correct splicing pattern, leading to the insertion of eight additional nucleotides in the variant transcript. Transcript analyses with minigene assays and cDNA from peripheral blood are useful tools for the characterization of splicing defects due to variants in the RPGR and may increase the diagnostic yield in RP. The functional analysis of non-canonical splice variants is required to classify those variants as pathogenic according to the ACMG's criteria.
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Affiliation(s)
- Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Tim Beltraminelli
- Department of Ophthalmology, Institute of Clinical Neurosciences of Southern Switzerland, Ente Ospedaliero Cantonale (EOC), 6962 Lugano, Switzerland
| | - Jordi Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Agnès Wlodarczyk
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Luzy Baehr
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital, University of Zurich, 8091 Zurich, Switzerland
| | - Moreno Menghini
- Department of Ophthalmology, Institute of Clinical Neurosciences of Southern Switzerland, Ente Ospedaliero Cantonale (EOC), 6962 Lugano, Switzerland
- Department of Ophthalmology, University Hospital, University of Zurich, 8091 Zurich, Switzerland
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), University and ETH Zurich, 8057 Zurich, Switzerland
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9
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Kuruvilla SE, Song E, Raoof N, van Bysterveldt K, Oliver VF, Hong SC, Al-Taie R, Wilson G, Vincent AL. Genotypic and phenotypic characterisation of RP2- and RPGR-associated X-linked inherited retinal dystrophy, including female manifestations. Clin Exp Ophthalmol 2023. [PMID: 36882936 DOI: 10.1111/ceo.14220] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/24/2023] [Accepted: 02/28/2023] [Indexed: 03/09/2023]
Abstract
BACKGROUND With the promise of gene replacement therapy, eligible males and females with X-linked inherited retinal dystrophy (XL-IRD) should be identified. METHODS Retrospective observational cohort study to establish the phenotypic and genotypic spectrum of XL-IRD within New Zealand (NZ). Thirty-two probands, including 9 females, with molecularly proven XL-IRD due to RP2 or RPGR mutations, and 72 family members, of which 43 were affected, were identified from the NZ IRD Database. Comprehensive ophthalmic phenotyping, familial cosegregation, genotyping, and bioinformatics were undertaken. Main outcome measures were: RP2 and RPGR pathogenic variant spectrum, phenotype in males and females (symptoms, age of onset, visual acuity, refraction, electrophysiology, autofluorescence, retinal appearance), and genotype-phenotype correlation. RESULTS For 32 families, 26 unique pathogenic variants were identified; in RP2 (n = 6, 21.9% of all families), RPGR exons 1-14 (n = 10, 43.75%), and RPGR-ORF15 (n = 10, 34.3%). Three RP2 and 8 RPGR exons 1-14 variants are novel, rare, and cosegregate. Thirty-one percent of carrier females were significantly affected, with 18.5% of families initially classified as autosomal dominant. Of five Polynesian families, 80% had novel disease-causing variants. One Māori family showed keratoconus segregating with an ORF15 variant. CONCLUSIONS Significant disease was present in 31% of genetically proven female carriers, often leading to an erroneous presumption of the inheritance pattern. Pathogenic variants in 44% of the families were in exon 1-14 of RPGR, more frequent than usually described, which may inform the gene testing algorithm. Proving cosegregation in families for novel variants and identifying affected females and males translates to optimised clinical care and potential for gene therapy.
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Affiliation(s)
- Shilpa E Kuruvilla
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Eileen Song
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Naz Raoof
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Katherine van Bysterveldt
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Verity F Oliver
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Sheng Chiong Hong
- Eye Department - Gisborne Hospital, Hauora Tairawhiti, Gisborne, New Zealand
| | - Rasha Al-Taie
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Department of Ophthalmology, Manukau Super Clinic, Counties Manukau District Health Board, Manukau, New Zealand
| | - Graham Wilson
- Eye Department - Gisborne Hospital, Hauora Tairawhiti, Gisborne, New Zealand
| | - Andrea L Vincent
- Department of Ophthalmology, Faculty of Medical and Health Sciences, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
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10
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Karali M, Testa F, Di Iorio V, Torella A, Zeuli R, Scarpato M, Romano F, Onore ME, Pizzo M, Melillo P, Brunetti-Pierri R, Passerini I, Pelo E, Cremers FPM, Esposito G, Nigro V, Simonelli F, Banfi S. Genetic epidemiology of inherited retinal diseases in a large patient cohort followed at a single center in Italy. Sci Rep 2022; 12:20815. [PMID: 36460718 PMCID: PMC9718770 DOI: 10.1038/s41598-022-24636-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 11/17/2022] [Indexed: 12/04/2022] Open
Abstract
Inherited retinal diseases (IRDs) are the leading cause of vision loss in the working-age population. We performed a retrospective epidemiological study to determine the genetic basis of IRDs in a large Italian cohort (n = 2790) followed at a single referral center. We provided, mainly by next generation sequencing, potentially conclusive molecular diagnosis for 2036 patients (from 1683 unrelated families). We identified a total of 1319 causative sequence variations in 132 genes, including 353 novel variants, and 866 possibly actionable genotypes for therapeutic approaches. ABCA4 was the most frequently mutated gene (n = 535; 26.3% of solved cases), followed by USH2A (n = 228; 11.2%) and RPGR (n = 102; 5.01%). The other 129 genes had a lower contribution to IRD pathogenesis (e.g. CHM 3.5%, RHO 3.5%; MYO7A 3.4%; CRB1 2.7%; RPE65 2%, RP1 1.8%; GUCY2D 1.7%). Seventy-eight genes were mutated in five patients or less. Mitochondrial DNA variants were responsible for 2.1% of cases. Our analysis confirms the complex genetic etiology of IRDs and reveals the high prevalence of ABCA4 and USH2A mutations. This study also uncovers genetic associations with a spectrum of clinical subgroups and highlights a valuable number of cases potentially eligible for clinical trials and, ultimately, for molecular therapies.
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Affiliation(s)
- Marianthi Karali
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy ,grid.9841.40000 0001 2200 8888Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy
| | - Francesco Testa
- grid.9841.40000 0001 2200 8888Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy
| | - Valentina Di Iorio
- grid.9841.40000 0001 2200 8888Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy
| | - Annalaura Torella
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy ,grid.410439.b0000 0004 1758 1171Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Roberta Zeuli
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy
| | - Margherita Scarpato
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy
| | - Francesca Romano
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy
| | - Maria Elena Onore
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy
| | - Mariateresa Pizzo
- grid.410439.b0000 0004 1758 1171Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Paolo Melillo
- grid.9841.40000 0001 2200 8888Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy
| | - Raffaella Brunetti-Pierri
- grid.9841.40000 0001 2200 8888Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy
| | - Ilaria Passerini
- grid.24704.350000 0004 1759 9494Department of Genetic Diagnosis, Careggi Teaching Hospital, Florence, Italy
| | - Elisabetta Pelo
- grid.24704.350000 0004 1759 9494Department of Genetic Diagnosis, Careggi Teaching Hospital, Florence, Italy
| | - Frans P. M. Cremers
- grid.10417.330000 0004 0444 9382Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Gabriella Esposito
- grid.4691.a0000 0001 0790 385XDepartment of Molecular Medicine and Medical Biotechnologies, University of Naples Federico II, Via Pansini 5, 80131 Naples, Italy ,CEINGE-Advanced Biotechnologies, Via G. Salvatore 486, 80145 Naples, Italy
| | - Vincenzo Nigro
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy ,grid.410439.b0000 0004 1758 1171Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Francesca Simonelli
- grid.9841.40000 0001 2200 8888Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Pansini 5, 80131 Naples, Italy
| | - Sandro Banfi
- grid.9841.40000 0001 2200 8888Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ’Luigi Vanvitelli’, Via Luigi De Crecchio 7, 80138 Naples, Italy ,grid.410439.b0000 0004 1758 1171Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
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11
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Mansouri V. X-Linked Retinitis Pigmentosa Gene Therapy: Preclinical Aspects. Ophthalmol Ther 2022; 12:7-34. [PMID: 36346573 PMCID: PMC9641696 DOI: 10.1007/s40123-022-00602-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Accepted: 10/17/2022] [Indexed: 11/11/2022] Open
Abstract
The most common inherited eye disease is retinitis pigmentosa (RP). X-linked RP (XLRP) is one of the most severe types of RP, with a considerable disease burden. Patients with XLRP experience a decrease in their vision and become blind in their 4th decade of life, causing much morbidity after starting a rather normal life. Treatment of XLRP remains challenging, and current treatments are not effective enough in restoring vision. Gene therapy of XLRP, capable of restoring the functional RPGR gene, showed promising results in preclinical studies and clinical trials; however, to date, no approved product has entered the market. The development of a gene therapy product needs through preliminary assessment of the drug in animal models before administration to humans. In this article, we reviewed the genetic pathology of XLRP, along with the preclinical aspects of the XLRP gene therapy, animal models, associated assessments, and future challenges and directions.
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Affiliation(s)
- Vahid Mansouri
- Gene Therapy Research Center, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
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12
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Nassisi M, De Bartolo G, Mohand-Said S, Condroyer C, Antonio A, Lancelot ME, Bujakowska K, Smirnov V, Pugliese T, Neidhardt J, Sahel JA, Zeitz C, Audo I. Retrospective Natural History Study of RPGR-Related Cone- and Cone-Rod Dystrophies While Expanding the Mutation Spectrum of the Disease. Int J Mol Sci 2022; 23:7189. [PMID: 35806195 PMCID: PMC9266815 DOI: 10.3390/ijms23137189] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 06/24/2022] [Accepted: 06/24/2022] [Indexed: 01/06/2023] Open
Abstract
Variants in the X-linked retinitis pigmentosa GTPase regulator gene (RPGR) and, specifically, in its retinal opening reading frame-15 isoform (RPGRORF15) may cause rod-cone (RCD), cone, and cone-rod dystrophies (CDs and CRDs). While RPGR-related RCDs have been frequently evaluated, the characteristics and progression of RPGR-related CD/CRDs are largely unknown. Therefore, the goal of our work was to perform genotype-phenotype correlations specifically in RPGRORF15-related CD/CRDs. This retrospective longitudinal study included 34 index patients and two affected relatives with a molecular diagnosis of RPGR-related CD/CRDs. Patients were recruited at the "Quinze-Vingts" Hospital, Paris, France and screened for mutations in RPGRORF15 at the Institut de la Vision, Paris, France. We identified 29 distinct variants, of which 27 were truncating. All were located in the 3' half of the RPGRORF15 transcript. Twenty of them were novel. Fifteen subjects were affected by CD, the remaining had CRD. When analyzing the longitudinal data, a progressive decline in visual acuity (VA) was noted, with more than 60% of the patients reaching VA ≥ 1 LogMar in the best eye after the fifth decade of life. To our knowledge, this is the largest described study of a cohort of CD/CRD patients affected by RPGRORF15 variants. Longitudinal data showed a rapidly progressive disease, possibly locating an optimal window of intervention for future therapies in younger ages.
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Affiliation(s)
- Marco Nassisi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, 75012 Paris, France
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
- Ophthalmology Unit, Fondazione IRCCS Ca’ Granda Ospedale Maggiore Policlinico di Milano, 20122 Milan, Italy
| | - Giuseppe De Bartolo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, 75012 Paris, France
| | - Saddek Mohand-Said
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, 75012 Paris, France
| | - Christel Condroyer
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
| | - Aline Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, 75012 Paris, France
| | - Marie-Elise Lancelot
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
| | - Kinga Bujakowska
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA
| | - Vasily Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Exploration de la Vision et Neuro-Ophthalmologie, Centre Hospitalier Universitaire de Lille, 59000 Lille, France
- Faculté de Médecine, Université de Lille, 59000 Lille, France
| | - Thomas Pugliese
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, 75012 Paris, France
| | - John Neidhardt
- Human Genetics, Faculty VI, School of Medicine and Health Sciences, University of Oldenburg, 26129 Oldenburg, Germany;
- Research Center Neurosensory Science, University Oldenburg, 26129 Oldenburg, Germany
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, 75012 Paris, France
- Department of Ophthalmology, University of Pittsburgh Medical School, Pittsburgh, PA 15213, USA
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (M.N.); (G.D.B.); (S.M.-S.); (C.C.); (A.A.); (M.-E.L.); (K.B.); (V.S.); (T.P.); (J.-A.S.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and INSERM-DGOS CIC 1423, 75012 Paris, France
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13
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Chahine Karam F, Loi TH, Ma A, Nash BM, Grigg JR, Parekh D, Riley LG, Farnsworth E, Bennetts B, Gonzalez-Cordero A, Jamieson RV. Human iPSC-Derived Retinal Organoids and Retinal Pigment Epithelium for Novel Intronic RPGR Variant Assessment for Therapy Suitability. J Pers Med 2022; 12:jpm12030502. [PMID: 35330501 PMCID: PMC8951517 DOI: 10.3390/jpm12030502] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 02/04/2023] Open
Abstract
The RPGR gene encodes Retinitis Pigmentosa GTPase Regulator, a known interactor with ciliary proteins, which is involved in maintaining healthy photoreceptor cells. Variants in RPGR are the main contributor to X-linked rod-cone dystrophy (RCD), and RPGR gene therapy approaches are in clinical trials. Hence, elucidation of the pathogenicity of novel RPGR variants is important for a patient therapy opportunity. Here, we describe a novel intronic RPGR variant, c.1415 − 9A>G, in a patient with RCD, which was classified as a variant of uncertain significance according to current clinical diagnostic criteria. The variant lay several base pairs intronic to the canonical splice acceptor site, raising suspicion of an RPGR RNA splicing abnormality and consequent protein dysfunction. To investigate disease causation in an appropriate disease model, induced pluripotent stem cells were generated from patient fibroblasts and differentiated to retinal pigment epithelium (iPSC-RPE) and retinal organoids (iPSC-RO). Abnormal RNA splicing of RPGR was demonstrated in patient fibroblasts, iPSC-RPE and iPSC-ROs, leading to a predicted frameshift and premature stop codon. Decreased RPGR expression was demonstrated in these cell types, with a striking loss of RPGR localization at the ciliary transitional zone, critically in the photoreceptor cilium of the patient iPSC-ROs. Mislocalisation of rhodopsin staining was present in the patient’s iPSC-RO rod photoreceptor cells, along with an abnormality of L/M opsin staining affecting cone photoreceptor cells and increased photoreceptor apoptosis. Additionally, patient iPSC-ROs displayed an increase in F-actin expression that was consistent with an abnormal actin regulation phenotype. Collectively, these studies indicate that the splicing abnormality caused by the c.1415 − 9A>G variant has an impact on RPGR function. This work has enabled the reclassification of this variant to pathogenic, allowing the consideration of patients with this variant having access to gene therapy clinical trials. In addition, we have identified biomarkers of disease suitable for the interrogation of other RPGR variants of uncertain significance.
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Affiliation(s)
- Fidelle Chahine Karam
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
| | - To Ha Loi
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
| | - Alan Ma
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Department of Clinical Genetics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
| | - Benjamin M. Nash
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
| | - John R. Grigg
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Specialty of Ophthalmology, Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
| | - Darshan Parekh
- Rare Diseases Functional Genomics Laboratory, Sydney Children’s Hospitals Network and Children’s Medical Research Institute, Westmead, Sydney 2145, Australia; (D.P.); (L.G.R.)
| | - Lisa G. Riley
- Rare Diseases Functional Genomics Laboratory, Sydney Children’s Hospitals Network and Children’s Medical Research Institute, Westmead, Sydney 2145, Australia; (D.P.); (L.G.R.)
- Specialty of Child and Adolescent Health, University of Sydney, Westmead, Sydney 2145, Australia
| | - Elizabeth Farnsworth
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
| | - Bruce Bennetts
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Sydney Genome Diagnostics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
| | - Anai Gonzalez-Cordero
- Stem Cell Medicine Group, Children’s Medical Research Institute, University of Sydney, Westmead, Sydney 2145, Australia;
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney 2006, Australia
| | - Robyn V. Jamieson
- Eye Genetics Research Unit, Children’s Medical Research Institute, Sydney Children’s Hospitals Network, Save Sight Institute, University of Sydney, Westmead, Sydney 2145, Australia; (F.C.K.); (T.H.L.); (A.M.); (B.M.N.); (J.R.G.)
- Department of Clinical Genetics, Western Sydney Genetics Program, Sydney Children’s Hospitals Network, Westmead, Sydney 2145, Australia
- Specialty of Genomic Medicine, Faculty of Medicine and Health, University of Sydney, Westmead, Sydney 2145, Australia; (E.F.); (B.B.)
- Correspondence: ; Tel.: +61-2-9687-2800; Fax: +61-2-9687-2120
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14
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Pulido JS, Procopio R, Davila HJ, Bello N, Ku C, Pennesi ME, Yang P, Nagiel A, Mahroo OA, Aleman TS, Salido EM, Reynolds M. Inherited Retinal Disease Panels-Caveat Emptor-Truly Know Your Inherited Retinal Disease Panel. Retina 2022; 42:1-3. [PMID: 34690342 PMCID: PMC8702468 DOI: 10.1097/iae.0000000000003319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Jose S Pulido
- Department of Ophthalmology, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania
- Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota
- Department of Molecular Medicine, Mayo Clinic, Rochester, Minnesota
| | - Rebecca Procopio
- Department of Ophthalmology, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Hiram J Davila
- Department of Ophthalmology, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Nicholas Bello
- Department of Ophthalmology, Wills Eye Hospital, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Cristy Ku
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Mark E Pennesi
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Paul Yang
- Department of Ophthalmology, Casey Eye Institute, Oregon Health & Science University, Portland, Oregon
| | - Aaron Nagiel
- The Vision Center, Children's Hospital Los Angeles, USC Roski Eye Institute, Keck School of Medicine University of Southern California, Los Angeles, California
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Department of Ophthalmology, Guy's and St Thomas' NHS Foundation Trust, London, United Kingdom
- Section of Ophthalmology, King's College London, London, United Kingdom
- Physiology, Development, and Neuroscience, University of Cambridge, Cambridge, United Kingdom
| | - Tomas S Aleman
- Department of Ophthalmology, Scheie Eye Institute at the Perelman Center for Advance Medicine and the Center for Advanced Retinal and Ocular Therapeutics (CAROT), University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- The Children's Hospital of Philadelphia (CHOP), Philadelphia, Pennsylvania
| | - Ezequiel M Salido
- Department of Biochemistry, Ophthalmology, and Visual Sciences, West Virginia University, Morgantown, West Virginia; and
| | - Margaret Reynolds
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis, Missouri
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15
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Yang J, Zhou L, Ouyang J, Xiao X, Sun W, Li S, Zhang Q. Genotype-Phenotype Analysis of RPGR Variations: Reporting of 62 Chinese Families and a Literature Review. Front Genet 2021; 12:600210. [PMID: 34745198 PMCID: PMC8565807 DOI: 10.3389/fgene.2021.600210] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 04/27/2021] [Indexed: 02/05/2023] Open
Abstract
Purpose RPGR is the most common cause of X-linked retinitis pigmentosa (RP), of which female carriers are also frequently affected. The aim of the current study was to explore the RPGR variation spectrum and associated phenotype based on the data from our lab and previous studies. Methods Variants in RPGR were selected from exome sequencing data of 7,092 probands with different eye conditions. The probands and their available family members underwent comprehensive ocular examinations. Similar data were collected from previous reports through searches in PubMed, Web of Science, and Google Scholar. Systematic analyses of genotypes, phenotypes and their correlations were performed. Results A total of 46 likely pathogenic variants, including nine missense and one in-frame variants in RCC1-like domain and 36 truncation variants, in RPGR were detected in 62 unrelated families in our in-house cohort. In addition, a total of 585 variants, including 491 (83.9%) truncation variants, were identified from the literature. Systematic analysis of variants from our in-house dataset, literature, and gnomAD suggested that most of the pathogenic variants of RPGR were truncation variants while pathogenic missense and in-frame variants were enriched in the RCC1-like domain. Phenotypic variations were present between males and female carriers, including more severe refractive error but better best corrected visual acuity (BCVA) in female carriers than those in males. The male patients showed a significant reduction of BCVA with increase of age and males with exon1-14 variants presented a better BCVA than those with ORF15 variants. For female carriers, the BCVA also showed significant reduction with increase of age, but BCVA in females with exon1-14 variants was not significant difference compared with those with ORF15 variants. Conclusion Most pathogenic variants of RPGR are truncations. Missense and in-frame variants located outside of the RCC1-like domain might be benign and the pathogenicity criteria for these variants should be considered with greater caution. The BCVA and refractive error are different between males and female carriers. Increase of age and location of variants in ORF15 contribute to the reduction of BCVA in males. These results are valuable for understanding genotypes and phenotypes of RPGR.
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Affiliation(s)
- Junxing Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Lin Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Jiamin Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Shiqiang Li
- 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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Di Iorio V, Karali M, Melillo P, Testa F, Brunetti-Pierri R, Musacchia F, Condroyer C, Neidhardt J, Audo I, Zeitz C, Banfi S, Simonelli F. Spectrum of Disease Severity in Patients With X-Linked Retinitis Pigmentosa Due to RPGR Mutations. Invest Ophthalmol Vis Sci 2021; 61:36. [PMID: 33372982 PMCID: PMC7774109 DOI: 10.1167/iovs.61.14.36] [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: 02/03/2023] Open
Abstract
Purpose The purpose of this study was to perform a detailed longitudinal phenotyping of X-linked retinitis pigmentosa (RP) caused by mutations in the RPGR gene during a long follow-up period. Methods An Italian cohort of 48 male patients (from 31 unrelated families) with RPGR-associated RP was clinically assessed at a single center (mean follow-up = 6.5 years), including measurements of best-corrected visual acuity (BCVA), Goldmann visual field (GVF), optical coherence tomography (OCT), fundus autofluorescence (FAF), microperimetry, and full-field electroretinography (ERG). Results Patients (29.6 ± 15.2 years) showed a mean BCVA of 0.6 ± 0.7 logMAR, mostly with myopic refraction (79.2%). Thirty patients (62.5%) presented a typical RP fundus, while the remaining sine pigmento RP. Over the follow-up, BCVA significantly declined at a mean rate of 0.025 logMAR/year. Typical RP and high myopia were associated with a significantly faster decline of BCVA. Blindness was driven primarily by GVF loss. ERG responses with a rod-cone pattern of dysfunction were detectable in patients (50%) that were significantly younger and more frequently presented sine pigmento RP. Thirteen patients (27.1%) had macular abnormalities without cystoid macular edema. Patients (50%) with a perimacular hyper-FAF ring were significantly younger, had a higher BCVA and a better-preserved ellipsoid zone band than those with markedly decreased FAF. Patients harboring pathogenic variants in exons 1 to 14 showed a milder phenotype compared to those with ORF15 mutations. Conclusions Our monocentric, longitudinal retrospective study revealed a spectrum disease progression in male patients with RPGR-associated RP. Slow disease progression correlated with sine pigmento RP, absence of high myopia, and mutations in RPGR exons 1 to 14.
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Affiliation(s)
- Valentina Di Iorio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania "Luigi Vanvitelli," Naples, Italy
| | - Marianthi Karali
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania "Luigi Vanvitelli," Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Paolo Melillo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania "Luigi Vanvitelli," Naples, Italy
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania "Luigi Vanvitelli," Naples, Italy
| | - Raffaella Brunetti-Pierri
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania "Luigi Vanvitelli," Naples, Italy
| | | | | | - John Neidhardt
- Human Genetics, Faculty of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany.,Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DGOS CIC, France.,Institute of Ophthalmology, University College of London, London, United Kingdom
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania "Luigi Vanvitelli," Naples, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania "Luigi Vanvitelli," Naples, Italy
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17
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Hadalin V, Šuštar M, Volk M, Maver A, Sajovic J, Jarc-Vidmar M, Peterlin B, Hawlina M, Fakin A. Cone Dystrophy Associated with a Novel Variant in the Terminal Codon of the RPGR- ORF15. Genes (Basel) 2021; 12:genes12040499. [PMID: 33805381 PMCID: PMC8066792 DOI: 10.3390/genes12040499] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/30/2022] Open
Abstract
Mutations in RPGRORF15 are associated with rod-cone or cone/cone-rod dystrophy, the latter associated with mutations at the distal end. We describe the phenotype associated with a novel variant in the terminal codon of the RPGRORF15 c.3457T>A (Ter1153Lysext*38), which results in a C-terminal extension. Three male patients from two families were recruited, aged 31, 35, and 38 years. Genetic testing was performed by whole exome sequencing. Filtered variants were analysed according to the population frequency, ClinVar database, the variant’s putative impact, and predicted pathogenicity; and were classified according to the ACMG guidelines. Examination included visual acuity (Snellen), colour vision (Ishihara), visual field, fundus autofluorescence (FAF), optical coherence tomography (OCT), and electrophysiology. All patients were myopic, and had central scotoma and reduced colour vision. Visual acuities on better eyes were counting fingers, 0.3 and 0.05. Electrophysiology showed severely reduced cone-specific responses and macular dysfunction, while the rod-specific response was normal. FAF showed hyperautofluorescent ring centred at the fovea encompassing an area of photoreceptor loss approximately two optic discs in diameter (3462–6342 μm). Follow up after 2–11 years showed enlargement of the diameter (avg. 100 μm/year). The novel c.3457T>A (Ter1153Lysext*38) mutation in the terminal RPGRORF15 codon is associated with cone dystrophy, which corresponds to the previously described phenotypes associated with mutations in the distal end of the RPGRORF15. Minimal progression during follow-up years suggests a relatively stable disease after the initial loss of the central cones.
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Affiliation(s)
- Vlasta Hadalin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Maja Šuštar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Marija Volk
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Aleš Maver
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Jana Sajovic
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Martina Jarc-Vidmar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Borut Peterlin
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
- Correspondence:
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18
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Georgiou M, Fujinami K, Michaelides M. Inherited retinal diseases: Therapeutics, clinical trials and end points-A review. Clin Exp Ophthalmol 2021; 49:270-288. [PMID: 33686777 DOI: 10.1111/ceo.13917] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/22/2021] [Accepted: 03/01/2021] [Indexed: 12/18/2022]
Abstract
Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of disorders characterised by photoreceptor degeneration or dysfunction. These disorders typically present with severe vision loss that can be progressive, with disease onset ranging from congenital to late adulthood. The advances in genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRDs, with the first approved gene therapy and the commencement of multiple clinical trials. The scope of this review is to familiarise clinicians and scientists with the current management and the prospects for novel therapies for: (1) macular dystrophies, (2) cone and cone-rod dystrophies, (3) cone dysfunction syndromes, (4) Leber congenital amaurosis, (5) rod-cone dystrophies, (6) rod dysfunction syndromes and (7) chorioretinal dystrophies. We also briefly summarise the investigated end points for the ongoing trials.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Kaoru Fujinami
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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19
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Georgiou M, Ali N, Yang E, Grewal PS, Rotsos T, Pontikos N, Robson AG, Michaelides M. Extending the phenotypic spectrum of PRPF8, PRPH2, RP1 and RPGR, and the genotypic spectrum of early-onset severe retinal dystrophy. Orphanet J Rare Dis 2021; 16:128. [PMID: 33712029 PMCID: PMC7953775 DOI: 10.1186/s13023-021-01759-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 02/25/2021] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To present the detailed retinal phenotype of patients with Leber Congenital Amaurosis/Early-Onset Severe Retinal Dystrophy (LCA/EOSRD) caused by sequence variants in four genes, either not (n = 1) or very rarely (n = 3) previously associated with the disease. METHODS Retrospective case series of LCA/EOSRD from four pedigrees. Chart review of clinical notes, multimodal retinal imaging, electrophysiology, and molecular genetic testing at a single tertiary referral center (Moorfields Eye Hospital, London, UK). RESULTS The mean age of presentation was 3 months of age, with disease onset in the first year of life in all cases. Molecular genetic testing revealed the following disease-causing variants: PRPF8 (heterozygous c.5804G > A), PRPH2 (homozygous c.620_627delinsTA, novel variant), RP1 (homozygous c.4147_4151delGGATT, novel variant) and RPGR (heterozygous c.1894_1897delGACA). PRPF8, PRPH2, and RP1 variants have very rarely been reported, either as unique cases or case reports, with limited clinical data presented. RPGR variants have not previously been associated with LCA/EOSRD. Clinical history and detailed retinal imaging are presented. CONCLUSIONS The reported cases extend the phenotypic spectrum of PRPF8-, PRPH2-, RP1-, and RPGR-associated disease, and the genotypic spectrum of LCA/EOSRD. The study highlights the importance of retinal and functional phenotyping, and the importance of specific genetic diagnosis to potential future therapy.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital, London, UK
| | | | | | | | - Tryfon Rotsos
- First Division of Ophthalmology, General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
- Moorfields Eye Hospital, London, UK.
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20
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Sánchez-Bellver L, Toulis V, Marfany G. On the Wrong Track: Alterations of Ciliary Transport in Inherited Retinal Dystrophies. Front Cell Dev Biol 2021; 9:623734. [PMID: 33748110 PMCID: PMC7973215 DOI: 10.3389/fcell.2021.623734] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/09/2021] [Indexed: 01/14/2023] Open
Abstract
Ciliopathies are a group of heterogeneous inherited disorders associated with dysfunction of the cilium, a ubiquitous microtubule-based organelle involved in a broad range of cellular functions. Most ciliopathies are syndromic, since several organs whose cells produce a cilium, such as the retina, cochlea or kidney, are affected by mutations in ciliary-related genes. In the retina, photoreceptor cells present a highly specialized neurosensory cilium, the outer segment, stacked with membranous disks where photoreception and phototransduction occurs. The daily renewal of the more distal disks is a unique characteristic of photoreceptor outer segments, resulting in an elevated protein demand. All components necessary for outer segment formation, maintenance and function have to be transported from the photoreceptor inner segment, where synthesis occurs, to the cilium. Therefore, efficient transport of selected proteins is critical for photoreceptor ciliogenesis and function, and any alteration in either cargo delivery to the cilium or intraciliary trafficking compromises photoreceptor survival and leads to retinal degeneration. To date, mutations in more than 100 ciliary genes have been associated with retinal dystrophies, accounting for almost 25% of these inherited rare diseases. Interestingly, not all mutations in ciliary genes that cause retinal degeneration are also involved in pleiotropic pathologies in other ciliated organs. Depending on the mutation, the same gene can cause syndromic or non-syndromic retinopathies, thus emphasizing the highly refined specialization of the photoreceptor neurosensory cilia, and raising the possibility of photoreceptor-specific molecular mechanisms underlying common ciliary functions such as ciliary transport. In this review, we will focus on ciliary transport in photoreceptor cells and discuss the molecular complexity underpinning retinal ciliopathies, with a special emphasis on ciliary genes that, when mutated, cause either syndromic or non-syndromic retinal ciliopathies.
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Affiliation(s)
- Laura Sánchez-Bellver
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
| | - Vasileios Toulis
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
| | - Gemma Marfany
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
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21
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Hu ML, Edwards TL, O'Hare F, Hickey DG, Wang JH, Liu Z, Ayton LN. Gene therapy for inherited retinal diseases: progress and possibilities. Clin Exp Optom 2021; 104:444-454. [PMID: 33689657 DOI: 10.1080/08164622.2021.1880863] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Inherited retinal diseases (IRDs) comprise a heterogeneous group of genetic disorders affecting the retina. Caused by mutations in over 300 genes, IRDs result in visual impairment due to dysfunction and degeneration of photoreceptors, retinal pigment epithelium, or the choroid. Important photoreceptor IRDs include retinitis pigmentosa and Leber congenital amaurosis. Macular dystrophies include Stargardt and Best disease. Currently, IRDs are largely incurable but the landscape of treatment options is rapidly changing for these diseases which, untreated, result in severe visual impairment and blindness.Advances in DNA delivery to the retina and improved genetic diagnosis of IRDs have led to a new era of research into gene therapy for these vision-threatening disorders. Gene therapy is a compelling approach due to the monogenic nature of most IRDs, with the retina being a favourable target for administering genetic vectors due to its immunoprivileged environment, direct visibility, and multiple methods to assess sensitivity and function. Generally, retinal gene therapy involves a subretinal or intravitreal injection of a viral vector, which infects target cells to deliver a therapeutic gene, or transgene. A gene augmentation strategy introduces a functioning copy of a gene to restore expression of a mutated gene, whereas a gene-editing strategy aims to directly edit and correct the mutation. Common delivery vectors include adeno-associated virus (AAV) and lentivirus.Voretigene neparvovec-rzyl (Luxturna) became the first FDA-approved direct gene therapy in December 2017, and the Australian TGA followed suit in August 2020. More are projected to follow, with clinical trials underway for many other IRDs.This review provides an overview of gene therapy for IRDs, including current progress and challenges. A companion article in this issue details target patient populations for IRD gene therapy, and how optometrists can assist in assessing individuals who may be eligible for current and future therapies.
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Affiliation(s)
- Monica L Hu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Thomas L Edwards
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia
| | - Fleur O'Hare
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia.,Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia
| | - Doron G Hickey
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Zhengyang Liu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Lauren N Ayton
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,Department of Surgery (Ophthalmology), Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia.,Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, the University of Melbourne, Melbourne, Australia
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22
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Kilgore DA, Kilgore TA, Sukpraprut-Braaten S, Schaefer GB, Uwaydat SH. Multimodal imaging of an RPGR carrier female. Ophthalmic Genet 2021; 42:312-316. [PMID: 33620278 DOI: 10.1080/13816810.2021.1881981] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Background: Retinitis pigmentosa GTPase regulator (RPGR) gene mutations are a common cause of X-linked retinitis pigmentosa and X-linked cone-rod dystrophy. There have been no previous reports of association with crystalline retinopathy or pseudo-crystalline retinopathy.Materials and Methods: We describe the history, clinical findings, retinal imaging, and electrodiagnostic studies of a patient with a tapetal-like reflex (TLR) and pseudo-crystalline retinopathy secondary to RPGR mutation.Case Description: Asymptomatic TLR secondary to RPGR mutation was diagnosed in a 14-year-old African American female with a family history of retinal dystrophy and no other past ophthalmic or medical history. Pseudo-crystalline retinopathy was observed on the Optos scanning laser ophthalmoscopy (SLO) imaging system but not on color fundus photography (CFP). Evidence of a TLR secondary to RPGR mutation was confirmed by CFP, autofluorescence, and genetic testing.Conclusion: We present a case of pseudo-crystalline retinopathy seen on Optos imaging in a patient with a TLR secondary to RPGR mutation.
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Affiliation(s)
- David A Kilgore
- Jones Eye Institute, Department of Ophthalmology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Tyler A Kilgore
- College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Suporn Sukpraprut-Braaten
- Department of Graduate Medical Education, Unity Health-White County Medical Center, Searcy, Arkansas, USA
| | - Gerald B Schaefer
- Department of Genetics, Arkansas Children's Hospital, Little Rock, Arkansas, USA
| | - Sami H Uwaydat
- Jones Eye Institute, Department of Ophthalmology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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23
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Abstract
Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population. The advances in ocular genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRD, with the first approved gene therapy and the commencement of multiple therapy trials. The scope of this review is to familiarize clinicians and scientists with the current landscape of retinal imaging in IRD. Herein we present in a comprehensive and concise manner the imaging findings of: (I) macular dystrophies (MD) [Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), pattern dystrophy (PRPH2), Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)], (II) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4 and RPGR), (III) cone dysfunction syndromes [achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6], blue-cone monochromatism (OPN1LW/OPN1MW array), oligocone trichromacy, bradyopsia (RGS9/R9AP) and Bornholm eye disease (OPN1LW/OPN1MW), (IV) Leber congenital amaurosis (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (V) rod-cone dystrophies [retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)], (VI) rod dysfunction syndromes (congenital stationary night blindness, fundus albipunctatus (RDH5), Oguchi disease (SAG, GRK1), and (VII) chorioretinal dystrophies [choroideremia (CHM), gyrate atrophy (OAT)].
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Kaoru Fujinami
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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24
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CLINICAL AND GENETIC CHARACTERISTICS OF MALE PATIENTS WITH RPGR-ASSOCIATED RETINAL DYSTROPHIES: A Long-Term Follow-up Study. Retina 2020. [PMID: 29528978 DOI: 10.1097/iae.0000000000002125] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe the phenotype and clinical course of patients with RPGR-associated retinal dystrophies, and to identify genotype-phenotype correlations. METHODS A multicenter medical records review of 74 male patients with RPGR-associated retinal dystrophies. RESULTS Patients had retinitis pigmentosa (RP; n = 52; 70%), cone dystrophy (COD; n = 5; 7%), or cone-rod dystrophy (CORD; n = 17; 23%). The median follow-up time was 11.6 years (range 0-57.1). The median age at symptom onset was 5.0 years (range 0-14 years) for patients with RP and 23.0 years (range 0-60 years) for patients with COD/CORD. The probability of being blind (best-corrected visual acuity <0.05) at the age of 40 was 20% and 55% in patients with RP and COD/CORD, respectively. RPGR-ORF15 mutations were associated with high myopia (P = 0.01), which led to a faster best-corrected visual acuity decline in patients with RP (P < 0.001) and COD/CORD (P = 0.03). Patients with RP with RPGR-ORF15 mutations had a faster visual field decline (P = 0.01) and thinner central retina (P = 0.03) than patients with mutations in exon 1 to 14. CONCLUSION Based on best-corrected visual acuity survival probabilities, the intervention window for gene therapy for RPGR-associated retinal dystrophies is relatively broad in patients with RP. RPGR-ORF15 mutations were associated with COD/CORD and with a more severe phenotype in RP. High myopia is a risk factor for faster best-corrected visual acuity decline.
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25
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Zou X, Fang S, Wu S, Li H, Sun Z, Zhu T, Wei X, Sui R. Detailed comparison of phenotype between male patients carrying variants in exons 1-14 and ORF15 of RPGR. Exp Eye Res 2020; 198:108147. [PMID: 32702353 DOI: 10.1016/j.exer.2020.108147] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 07/05/2020] [Accepted: 07/08/2020] [Indexed: 12/19/2022]
Abstract
PURPOSE To compare disease severity in detail between patients carrying variants in exons 1-14 and ORF15 of retinitis pigmentosa GTPase regulator (RPGR). METHODS Systematic next-generation sequencing data analysis, Sanger sequencing validation and segregation analysis were utilised to identify the pathogenic variants. Detailed ophthalmic examinations, including electroretinograms, fundus photography, fundus autofluorescence and optical coherence tomography were performed. Statistical analysis, including age adjustment and comparison, were performed based on cross-sectional level to compare disease severity between variants in the two RPGR variant groups. RESULTS Sixty-two variants were identified in RPGR in 86 patients from 77 unrelated families. Twenty-nine (37.7%) had variants in RPGR-exons 1-14 (group 1) and 48 (62.3%) in RPGR-ORF15 (group 2). Eighty-four patients were diagnosed with X-linked retinitis pigmentosa and only two patients with cone-rod dystrophy. LogMAR visual acuity increased 0.035 and 0.022 each year on average in group 1 and group 2, respectively. Group 2 patients had better visual acuity with a mean logMAR difference of 0.4378, which is significant after age adjustment (P < 0.01). Neither the value of log (ellipsoid zone width) nor central retinal thickness was significantly correlated with variant grouping after considering the effect of the age variable (P = 0.56 and 0.40, respectively). Spherical refractive error did not differ significantly between the two variant groups (P = 0.17). Patterns of autofluorescence included a hyperfluorescent ring at the posterior pole, diffuse hyperfluorescence in the macular area, and dark macular autofluorescence with or without fovea hyperfluorescence. The age and proportion of fundus autofluorescence patterns between the two variant groups were significantly different (P < 0.01). CONCLUSIONS Patients with variants in exons 1-14 retained less visual acuity than patients with ORF15 variants and deteriorated faster. However, the ellipsoid zone widths, central retinal thickness and refractions were comparable between the two groups. Autofluorescence pattern relates to the age and the variant grouping.
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Affiliation(s)
- Xuan Zou
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Sha Fang
- School of Statistics, Capital University of Economics and Business, Beijing, 100070, China
| | - Shijing Wu
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Hui Li
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Zixi Sun
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Tian Zhu
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Xing Wei
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China
| | - Ruifang Sui
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, 100730, China.
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Maggi J, Roberts L, Koller S, Rebello G, Berger W, Ramesar R. De Novo Assembly-Based Analysis of RPGR Exon ORF15 in an Indigenous African Cohort Overcomes Limitations of a Standard Next-Generation Sequencing (NGS) Data Analysis Pipeline. Genes (Basel) 2020; 11:genes11070800. [PMID: 32679846 PMCID: PMC7396994 DOI: 10.3390/genes11070800] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 06/24/2020] [Accepted: 07/13/2020] [Indexed: 01/10/2023] Open
Abstract
RPGR exon ORF15 variants are one of the most frequent causes for inherited retinal disorders (IRDs), in particular retinitis pigmentosa. The low sequence complexity of this mutation hotspot makes it prone to indels and challenging for sequence data analysis. Whole-exome sequencing generally fails to provide adequate coverage in this region. Therefore, complementary methods are needed to avoid false positives as well as negative results. In this study, next-generation sequencing (NGS) was used to sequence long-range PCR amplicons for an IRD cohort of African ancestry. By developing a novel secondary analysis pipeline based on de novo assembly, we were able to avoid the miscalling of variants generated by standard NGS analysis tools. We identified pathogenic variants in 11 patients (13% of the cohort), two of which have not been reported previously. We provide a novel and alternative end-to-end secondary analysis pipeline for targeted NGS of ORF15 that is less prone to false positive and negative variant calls.
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Affiliation(s)
- Jordi Maggi
- Institute of Medical Molecular Genetic, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.)
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8006 Zurich, Switzerland
| | - Lisa Roberts
- University of Cape Town/MRC Genomic and Precision Medicine Research Unit, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (L.R.); (G.R.); (R.R.)
| | - Samuel Koller
- Institute of Medical Molecular Genetic, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.)
| | - George Rebello
- University of Cape Town/MRC Genomic and Precision Medicine Research Unit, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (L.R.); (G.R.); (R.R.)
| | - Wolfgang Berger
- Institute of Medical Molecular Genetic, University of Zurich, 8952 Schlieren, Switzerland; (J.M.); (S.K.)
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8006 Zurich, Switzerland
- Neuroscience Center Zurich (ZNZ), University and ETH Zurich, 8006 Zurich, Switzerland
- Correspondence:
| | - Rajkumar Ramesar
- University of Cape Town/MRC Genomic and Precision Medicine Research Unit, Division of Human Genetics, Department of Pathology, Institute of Infectious Disease and Molecular Medicine (IDM), Faculty of Health Sciences, University of Cape Town, Cape Town 7925, South Africa; (L.R.); (G.R.); (R.R.)
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Salvetti AP, Nanda A, MacLaren RE. RPGR-Related X-Linked Retinitis Pigmentosa Carriers with a Severe "Male Pattern". Ophthalmologica 2020; 244:60-67. [PMID: 32434206 DOI: 10.1159/000503687] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2019] [Accepted: 09/25/2019] [Indexed: 11/19/2022]
Abstract
BACKGROUND X-linked retinitis pigmentosa (XLRP) due to mutations in the RPGR gene is a very severe form of RP, resulting in rapid disease progression and retinal dysfunction. Female carriers do not usually report symptoms. However, it has reported that carriers of XLRP can have a significant visual and retinal impairment. OBJECTIVES To report a detailed description of 3 cases of severely affected females who presented with a "male" phenotype and have posed challenges at diagnosis, due to the apparent autosomal dominant family history. METHOD Autofluorescence imaging (AF), colour imaging and optical coherence tomography (OCT) were performed. Confirmation of the genetic mutation was obtained by Sanger genetic sequencing. In 1 patient an X-inactivation analysis was performed to detect the X-inactivation ratio, as the percentage of cells tested in which each allele is active. RESULTS All the patients started suffering from night blindness in early childhood. Colour, fundus AF and OCT images showed the typical pattern of degeneration reported in men. One patient underwent retina implant surgery due to the severe atrophy. CONCLUSIONS This is a small selection of females with a severe phenotype that do not differ from the typical male phenotype. In our opinion gene therapy surgery should be warranted in this scenario.
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Affiliation(s)
- Anna Paola Salvetti
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, and Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Anika Nanda
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, and Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
| | - Robert E MacLaren
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, and Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom,
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Abstract
PURPOSE To examine the features of the tapetal-like reflex (TLR) in female carriers of RPGR-associated retinopathy by means of adaptive optics scanning light ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography. METHODS Nine molecularly confirmed RPGR carriers and three healthy controls underwent ocular examination and the following retinal imaging modalities: color photography, near-infrared reflectance, fundus autofluorescence, spectral domain optical coherence tomography, and AOSLO. After identifying TLR areas across all imaging modalities, normalized local contrast of outer retinal bands on spectral domain optical coherence tomography was calculated and AOSLO-acquired photoreceptor mosaic analysis was performed. RESULTS Seven carriers had TLR areas, which colocalized with increased rod photoreceptor reflectivity on confocal AOSLO and reduced cone photoreceptor densities. Parafoveal TLR areas also exhibited reduced local contrast (i.e., increased reflectivity) of the outer retinal bands on spectral domain optical coherence tomography (inner segment ellipsoid zone and outer segment interdigitation zone). Healthy controls did not show TLR. CONCLUSION The cellular resolution provided by AOSLO affords the characterization of the photoreceptor mosaic in RPGR carriers with a TLR. Features revealed include reduced cone density, increased cone inner segment diameter, and increased rod outer segment reflectivity.
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Menghini M, Jolly JK, Nanda A, Wood L, Cehajic-Kapetanovic J, MacLaren RE. Early Cone Photoreceptor Outer Segment Length Shortening in RPGR X-Linked Retinitis Pigmentosa. Ophthalmologica 2020; 244:281-290. [PMID: 32209785 DOI: 10.1159/000507484] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 03/24/2020] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Introduction of retinal gene therapy requires established outcome measures along with thorough understanding of the pathophysiology. Evidence of early, thinned outer segments in RPGR X-linked retinitis pigmentosa could help understand how the level of cone photoreceptor involvement translates to visual potential. OBJECTIVE Analysis of foveal photoreceptor outer segment length in a young cohort of RPGR patients to help clarify the reason for absent maximal visual acuity seen. METHODS Case-control study of RPGR patients. Quantitative measurement of photoreceptor outer segment by OCT. RESULTS Eighteen male RPGR patients and 30 normal subjects were included. Outer segment thickness differed significantly between the RPGR and normal eyes (p < 0.0005). Mean outer segment values were 35.6 ± 2.3 µm and 35.4 ± 2.6 µm for RPGR right and left eyes, respectively. In normal eyes, the mean outer segment thickness was 61.4 ± 0.7 µm for right eyes and 62.4 ± 0.7 µm for left eyes. CONCLUSIONS Patients with RPGR X-linked retinitis pigmentosa show thinning of the foveal photoreceptor outer segment thickness early in the disease course, which could be an explanation for the lower maximum visual acuity seen. These findings must be taken into consideration when assessing efficacy outcome measures in retinal gene therapy trials.
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Affiliation(s)
- Moreno Menghini
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK,
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK,
| | - Jasleen K Jolly
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Anika Nanda
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Laura Wood
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford, UK
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
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Dufour VL, Cideciyan AV, Ye GJ, Song C, Timmers A, Habecker PL, Pan W, Weinstein NM, Swider M, Durham AC, Ying GS, Robinson PM, Jacobson SG, Knop DR, Chulay JD, Shearman MS, Aguirre GD, Beltran WA. Toxicity and Efficacy Evaluation of an Adeno-Associated Virus Vector Expressing Codon-Optimized RPGR Delivered by Subretinal Injection in a Canine Model of X-linked Retinitis Pigmentosa. Hum Gene Ther 2020; 31:253-267. [PMID: 31910043 DOI: 10.1089/hum.2019.297] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Applied Genetic Technologies Corporation (AGTC) is developing a recombinant adeno-associated virus (rAAV) vector AGTC-501, also designated rAAV2tYF-GRK1-hRPGRco, to treat X-linked retinitis pigmentosa (XLRP) in patients with mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene. The vector contains a codon-optimized human RPGR cDNA (hRPGRco) driven by a photoreceptor-specific promoter (G protein-coupled receptor kinase 1 [GRK1]), and is packaged in an AAV2 capsid variant with three surface tyrosine residues changed to phenylalanine (AAV2tYF). We conducted a toxicity and efficacy study of this vector administered by subretinal injection in the naturally occurring RPGR mutant (X-linked progressive retinal atrophy 2 [XLPRA2]) dog model. Sixteen RPGR mutant dogs divided into four groups of three to five animals each received either a subretinal injection of 0.07 mL of AGTC-501 at low (1.2 × 1011 vector genome [vg]/mL), mid (6 × 1011 vg/mL), or high dose (3 × 1012 vg/mL), or of vehicle control in the right eye at early-stage disease. The left eye remained untreated. Subretinal injections were well tolerated and were not associated with systemic toxicity. Electroretinography, in vivo retinal imaging, and histological analysis showed rescue of photoreceptor function and structure in the absence of ocular toxicity in the low- and mid-dose treatment groups when compared with the vehicle-treated group. The high-dose group showed evidence of both photoreceptor rescue and posterior segment toxicity. These results support the use of AGTC-501 in clinical studies with patients affected with XLRP caused by RPGR mutations and define the no-observed-adverse-effect level at 6 × 1011 vg/mL.
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Affiliation(s)
- Valérie L Dufour
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Guo-Jie Ye
- Applied Genetic Technologies Corporation, Alachua, Florida
| | - Chunjuan Song
- Applied Genetic Technologies Corporation, Alachua, Florida
| | - Adrian Timmers
- Applied Genetic Technologies Corporation, Alachua, Florida
| | - Perry L Habecker
- Department of Pathobiology, New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Kennett Square, Pennsylvania
| | - Wei Pan
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nicole M Weinstein
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Malgorzata Swider
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Amy C Durham
- Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Gui-Shuang Ying
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | | | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - David R Knop
- Applied Genetic Technologies Corporation, Alachua, Florida
| | | | | | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - William A Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
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Zhang Z, Dai H, Wang L, Tao T, Xu J, Sun X, Yang L, Li G. Novel mutations of RPGR in Chinese families with X-linked retinitis pigmentosa. BMC Ophthalmol 2019; 19:240. [PMID: 31775781 PMCID: PMC6882249 DOI: 10.1186/s12886-019-1250-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 11/18/2019] [Indexed: 12/15/2022] Open
Abstract
Background RP (retinitis pigmentosa) is a group of hereditary retinal degenerative diseases. XLRP is a relatively severe subtype of RP. Thus, it is necessary to identify genes and mutations in patients who present with X-linked retinitis pigmentosa. Methods Genomic DNA was extracted from peripheral blood. The coding regions and intron-exon boundaries of the retinitis pigmentosa GTPase regulator (RPGR) and RP2 genes were amplified by PCR and then sequenced directly. Ophthalmic examinations were performed to identify affected individuals from two families and to characterize the phenotype of the disease. Results Mutation screening demonstrated two novel nonsense mutations (c.1541C > G; p.S514X and c.2833G > T; p.E945X) in the RPGR gene. The clinical manifestation of family 1 with mutations in exon 13 was mild. Genotype-phenotype correlation analysis suggested that patients with mutations close to the downstream region of ORF15 in family 2 manifested an early loss of cone function. Family 2 carried a nonsense mutation in ORF15 that appeared to have a semi-dominant pattern of inheritance. All male patients and two female carriers in family 2 manifested pathological myopia (PM), indicating that there may be a distinctive X-linked genotype-phenotype correlation between RP and PM. Conclusions We identified two novel mutations of the RPGR gene, which broadens the spectrum of RPGR mutations and the phenotypic spectrum of the disease in Chinese families.
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Affiliation(s)
- Zhimeng Zhang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, People's Republic of China
| | - Hehua Dai
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, People's Republic of China
| | - Lei Wang
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, People's Republic of China
| | - Tianchang Tao
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, People's Republic of China
| | - Jing Xu
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, People's Republic of China
| | - Xiaowei Sun
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, People's Republic of China
| | - Liping Yang
- Department of Ophthalmology, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Peking University Third Hospital, Beijing, People's Republic of China
| | - Genlin Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University; Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, People's Republic of China.
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QUANTITATIVE ANALYSIS OF HYPERAUTOFLUORESCENT RINGS TO CHARACTERIZE THE NATURAL HISTORY AND PROGRESSION IN RPGR-ASSOCIATED RETINOPATHY. Retina 2019; 38:2401-2414. [PMID: 29016458 PMCID: PMC5797695 DOI: 10.1097/iae.0000000000001871] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Seventy to eighty percent of X-linked retinitis pigmentosa are associated with RPGR mutations. This disease-specific autofluorescence study provides data on baseline values, progression rates, symmetry, and associations with age and genotype. These findings can guide future treatment trials and contribute to clinical care of patients with RPGR-associated retinitis pigmentosa. Purpose: Quantitative analysis of hyperautofluorescent rings and progression in subjects with retinitis pigmentosa associated with retinitis pigmentosa GTPase regulator (RPGR) gene mutations. Methods: Prospective observational study of 46 subjects. Ring area, horizontal and vertical diameter measurements taken from outer and inner ring borders. Intraobserver repeatability, baseline measurements, progression rates, interocular symmetry, and association with age and genotype were investigated. Results: Baseline ring area was 11.8 ± 13.4 mm2 and 11.4 ± 13.2 mm2 for right and left eyes, respectively, with very strong interocular correlation (r = 0.9398; P < 0.0001). Ring area constriction was 1.5 ± 2.0 mm2/year and 1.3 ± 1.9 mm2/year for right and left eyes, respectively, with very strong interocular correlation (r = 0.878, P < 0.0001). Baseline ring area and constriction rate correlated negatively with age (r = −0.767; P < 0.0001 and r = −0.644, P < 0.0001, respectively). Constriction rate correlated strongly with baseline area (r = 0.850, P < 0.0001). Age, but not genotype, exerted a significant effect on constriction rates (P < 0.0001), with greatest rates of progression seen in younger subjects. An exponential decline overall was found. Conclusion: This study provides disease-specific baseline values and progression rates together with a repeatability assessment of fundus autofluorescence metrics. Our findings can guide future treatment trials and contribute to the clinical care of patients with RPGR-associated retinitis pigmentosa.
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Mawatari G, Fujinami K, Liu X, Yang L, Yokokawa YF, Komori S, Ueno S, Terasaki H, Katagiri S, Hayashi T, Kuniyoshi K, Miyake Y, Tsunoda K, Yoshitake K, Iwata T, Nao-i N. Clinical and genetic characteristics of 14 patients from 13 Japanese families with RPGR-associated retinal disorder: report of eight novel variants. Hum Genome Var 2019; 6:34. [PMID: 31645972 PMCID: PMC6804603 DOI: 10.1038/s41439-019-0065-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 05/21/2019] [Accepted: 06/30/2019] [Indexed: 01/08/2023] Open
Abstract
Variants in the retinitis pigmentosa GTPase regulator (RPGR) gene are a major cause of X-linked inherited retinal disorder (IRD). We herein describe the clinical and genetic features of 14 patients from 13 Japanese families harboring RPGR variants in a nationwide cohort. Comprehensive ophthalmological examinations were performed to classify the patients into one of the phenotype subgroups: retinitis pigmentosa (RP) and cone rod dystrophy (CORD). The mean age of onset/at examination was 13.8/38.1 years (range, 0-50/11-72), respectively. The mean visual acuity in the right/left eye was 0.43/0.43 (range, 0.1-1.7/-0.08-1.52) LogMAR unit. Eight patients had RP, and six had CORD. Whole-exome sequencing with target analyses identified 13 RPGR variants in 730 families with IRD, including 8 novel variants. An association between the phenotype subgroup and the position of variants (cutoff of amino acid 950) was revealed. To conclude, the clinical and genetic spectrum of RPGR-associated retinal disorder was first illustrated in a Japanese population, with a high proportion of novel variants. These results suggest the distinct genetic background of RPGR in the Japanese population, in which the genotype-phenotype association was affirmed. This evidence should be helpful monitoring and counseling patients and in selecting patients for future therapeutic trials.
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Affiliation(s)
- Go Mawatari
- Department of Ophthalmology, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki, Japan
| | - Kaoru Fujinami
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- UCL Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
| | - Xiao Liu
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, China
| | - Lizhu Yang
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Yu-Fujinami Yokokawa
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Graduate School of Health Management, Keio University, Tokyo, Japan
- Division of Public Health, Yokokawa Clinic, Suita, Osaka, Japan
| | - Shiori Komori
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi Japan
| | - Satoshi Katagiri
- Department of Ophthalmology, The Jikei University School of Medicine, Nishi-Shimbashi, Minato-ku, Tokyo, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Nishi-Shimbashi, Minato-ku, Tokyo, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kinki University Faculty of Medicine, Osaka-Sayama City, Osaka, Japan
| | - Yozo Miyake
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Kobe Eye Center, Next Vision, Kobe, Hyogo, Japan
| | - Kazushige Tsunoda
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
| | - Kazutoshi Yoshitake
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
| | - Nobuhisa Nao-i
- Department of Ophthalmology, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki, Japan
| | - on behalf of the JEGC study group
- Department of Ophthalmology, Faculty of Medicine, University of Miyazaki, Kiyotake, Miyazaki, Japan
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
- UCL Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
- Southwest Hospital/Southwest Eye Hospital, Third Military Medical University, Chongqing, China
- Graduate School of Health Management, Keio University, Tokyo, Japan
- Division of Public Health, Yokokawa Clinic, Suita, Osaka, Japan
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Showa-ku, Nagoya, Aichi Japan
- Department of Ophthalmology, The Jikei University School of Medicine, Nishi-Shimbashi, Minato-ku, Tokyo, Japan
- Department of Ophthalmology, Kinki University Faculty of Medicine, Osaka-Sayama City, Osaka, Japan
- Kobe Eye Center, Next Vision, Kobe, Hyogo, Japan
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Meguro-ku, Tokyo, Japan
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Chen HY, Welby E, Li T, Swaroop A. Retinal disease in ciliopathies: Recent advances with a focus on stem cell-based therapies. ACTA ACUST UNITED AC 2019; 4:97-115. [PMID: 31763178 PMCID: PMC6839492 DOI: 10.3233/trd-190038] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ciliopathies display extensive genetic and clinical heterogeneity, varying in severity, age of onset, disease progression and organ systems affected. Retinal involvement, as demonstrated by photoreceptor dysfunction or death, is a highly penetrant phenotype among a vast majority of ciliopathies. Photoreceptor cells possess a specialized and modified sensory cilium with membrane discs where efficient photon capture and ensuing signaling cascade initiate the visual process. Disruptions of cilia biogenesis and protein transport lead to impairment of photoreceptor function and eventually degeneration. Despite advances in elucidation of ciliogenesis and photoreceptor cilia defects, we have limited understanding of pathogenic mechanisms underlying retinal phenotype(s) observed in human ciliopathies. Patient-derived induced pluripotent stem cell (iPSC)-based approaches offer a unique opportunity to complement studies with model organisms and examine cilia disease relevant to humans. Three-dimensional retinal organoids from iPSC lines feature laminated cytoarchitecture, apical-basal polarity and emergence of a ciliary structure, thereby permitting pathogenic modeling of human photoreceptors in vitro. Here, we review the biology of photoreceptor cilia and associated defects and discuss recent progress in evolving treatment modalities, especially using patient-derived iPSCs, for retinal ciliopathies.
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Affiliation(s)
- Holly Yu Chen
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Emily Welby
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Tiansen Li
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
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Sanchez Tocino H, Diez Montero C, Villanueva Gómez A, Lobo Valentin R, Montero-Moreno JA. Phenotypic high myopia in X-linked retinitis pigmentosa secondary to a novel mutation in the RPGR gene. Ophthalmic Genet 2019; 40:170-176. [DOI: 10.1080/13816810.2019.1605385] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
| | | | - Ana Villanueva Gómez
- Pediatric Ophthalmology Unit, Rio Hortega University Hospital, Valladolid, Spain
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Chiang JPW, Lamey TM, Wang NK, Duan J, Zhou W, McLaren TL, Thompson JA, Ruddle J, De Roach JN. Development of High-Throughput Clinical Testing of RPGR ORF15 Using a Large Inherited Retinal Dystrophy Cohort. Invest Ophthalmol Vis Sci 2019; 59:4434-4440. [PMID: 30193314 DOI: 10.1167/iovs.18-24555] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Mutations in the ORF15 region of RPGR account for approximately half of all X-linked retinitis pigmentosa cases. However, a robust high-throughput method for the detection of ORF15 mutations has yet to be validated. We set out to develop the first clinically validated next-generation sequencing (NGS) method for the detection of mutations in this difficult-to-sequence region, including test accuracy and coverage data. Methods As part of a blind-test, 145 research samples, previously tested by Sanger sequencing, and 81 clinical samples were evaluated using NGS of long-range PCR products fragmented with Illumina's Nextera library preparation kit (method 1), or with Centrillion's OneTube technology, supplemented with duplication analysis using an ORF15-specific in-silico array (method 2). DNA fragments were analyzed using Agilent's DNA 1000 assay, and sequencing was done on Illumina's MiSeq 2×150 or HiSeq2500 2×100. NextGENe by SoftGenetics was used for data analysis and variant calling. Results The Nextera library preparation method produced 24 cases of discordance due to (in order of decreasing occurrence) false-negatives, incorrectly called variants, and a false-positive. Subsequent use of a new, OneTube NGS library preparation method, supplemented with duplication analyses, resolved discordance between Sanger and NGS data in all cases. This improvement in variant detection accuracy was largely attributed to improvement in random fragmentation offered by the enzymatic OneTube method, resulting in more complete coverage of the highly repetitive ORF15 region. Minimum coverage was roughly 320 reads for Nextera and 6800 reads for OneTube (normalized for total read counts). Conclusions This paper documents the first clinically validated NGS method for reliable, high-throughput sequencing of RPGR ORF15. Sensitivity and specificity of the new method were 100%, with the caveat of unclear zygosity calling for one large duplication case. These findings demonstrate a reliable and practical implementation for NGS-based diagnosis of RPGR ORF15 mutations. They also provide the foundation for targeted, high-coverage sequencing of any other repetitive regions within the genome.
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Affiliation(s)
- John P W Chiang
- Molecular Vision Laboratory, Hillsboro, Oregon, United States
| | - Tina M Lamey
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
| | - Nicholas K Wang
- Molecular Vision Laboratory, Hillsboro, Oregon, United States
| | - Jie Duan
- Molecular Vision Laboratory, Hillsboro, Oregon, United States
| | - Wei Zhou
- Centrillion Technologies, Palo Alto, California, United States
| | - Terri L McLaren
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Jennifer A Thompson
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | | | - John N De Roach
- Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.,Centre for Ophthalmology and Visual Science, The University of Western Australia, Crawley, Western Australia, Australia
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Zhang X, Shahani U, Reilly J, Shu X. Disease mechanisms and neuroprotection by tauroursodeoxycholic acid in Rpgr knockout mice. J Cell Physiol 2019; 234:18801-18812. [PMID: 30924157 DOI: 10.1002/jcp.28519] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 02/22/2019] [Accepted: 03/06/2019] [Indexed: 12/16/2022]
Abstract
Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene are the predominant cause of retinitis pigmentosa. RPGR plays a critical role as a scaffold protein in the regulation of protein trafficking from the basal body to the axoneme, where the cargoes are transported to the outer segments (OSs) of photoreceptors. This trafficking process is controlled directly by intraflagellar transport complexes and regulated by the RPGR protein complex, although the precise mechanisms have yet to be defined. We used an Rpgr conditional knockout (cko) mouse model to investigate the disease mechanisms during retinal degeneration and to evaluate the protective effects of tauroursodeoxycholic acid (TUDCA). Rhodopsin, cone opsins and transducin were mislocalized in Rpgr cko photoreceptors, while localization of NPHP4 to connecting cilia was absent, suggesting that RPGR is required for ciliary protein trafficking. Microglia were activated in advance of retinal degeneration in Rpgr cko mouse retinas. TUDCA treatment suppressed microglial activation and inflammation and prevented photoreceptor degeneration in Rpgr cko mice. Our data demonstrated that TUDCA has therapeutic potential for RPGR-associated RP patients.
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Affiliation(s)
- Xun Zhang
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, Scotland
| | - Uma Shahani
- Department of Vision Science, Glasgow Caledonian University, Glasgow, Scotland
| | - James Reilly
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, Scotland
| | - Xinhua Shu
- Department of Biological and Biomedical Sciences, Glasgow Caledonian University, Glasgow, Scotland.,Department of Vision Science, Glasgow Caledonian University, Glasgow, Scotland
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Tee JJL, Yang Y, Kalitzeos A, Webster A, Bainbridge J, Michaelides M. Natural History Study of Retinal Structure, Progression, and Symmetry Using Ellipzoid Zone Metrics in RPGR-Associated Retinopathy. Am J Ophthalmol 2019; 198:111-123. [PMID: 30312579 PMCID: PMC6355316 DOI: 10.1016/j.ajo.2018.10.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/30/2018] [Accepted: 10/01/2018] [Indexed: 11/19/2022]
Abstract
PURPOSE This is a quantitative study of retinal structure, progression rates, and interocular symmetry in retinitis pigmentosa GTPase regulator gene (RPGR)-associated retinopathy using spectral-domain optical coherence tomography (OCT). DESIGN Prospective, observational cohort study. METHODS Thirty-eight subjects at Moorfields Eye Hospital in London were assessed with 2 spectral-domain OCT-derived ellipzoid zone (EZ) metrics with repeatability assessments. EZ width (EZW) measurements were made on transfoveal line scans. En face images of the EZ area (EZA) were generated from high-density macular volume scans and were quantified. Baseline size, progression rate, symmetry, associations with age and genotype, and baseline structure-function correlation were investigated. RESULTS Baseline EZW and EZA measurements were 1963.6 μm and 3.70 mm2, respectively. The mean EZW progression rate was 233.6 μm per year, and the mean EZA rate was 0.67 mm2 per year. Relative interocular difference as an index of symmetry was 3% for both metrics, indicating good baseline symmetry in general-although significant variation existed across the cohort. Analysis of variance found a significant effect of age but not genotype on EZ dimension and progression rates. Larger EZ dimension and greater progression were seen in younger subjects. A positive correlation between EZ dimension and progression was evident. Overall exponential decline rates of 8.2% with EZW and 15.5% with EZA were obtained. Good functional correlation was found with EZW demonstrating stronger correlation; however, EZA correlation with function was also significant. CONCLUSIONS EZ metrics are sensitive structural biomarkers for measuring residual extent and progression in RPGR-associated retinopathy. Our elucidation of the natural history will provide clinicians and patients with more knowledge about the condition and inform the design and interpretation of interventional trials.
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Affiliation(s)
- James J L Tee
- University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom
| | - Yesa Yang
- University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom
| | - Angelos Kalitzeos
- University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom
| | - Andrew Webster
- University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom
| | - James Bainbridge
- University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom
| | - Michel Michaelides
- University College London Institute of Ophthalmology and Moorfields Eye Hospital, London, United Kingdom.
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Gill JS, Georgiou M, Kalitzeos A, Moore AT, Michaelides M. Progressive cone and cone-rod dystrophies: clinical features, molecular genetics and prospects for therapy. Br J Ophthalmol 2019; 103:bjophthalmol-2018-313278. [PMID: 30679166 PMCID: PMC6709772 DOI: 10.1136/bjophthalmol-2018-313278] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 11/23/2018] [Accepted: 11/29/2018] [Indexed: 12/16/2022]
Abstract
Progressive cone and cone-rod dystrophies are a clinically and genetically heterogeneous group of inherited retinal diseases characterised by cone photoreceptor degeneration, which may be followed by subsequent rod photoreceptor loss. These disorders typically present with progressive loss of central vision, colour vision disturbance and photophobia. Considerable progress has been made in elucidating the molecular genetics and genotype-phenotype correlations associated with these dystrophies, with mutations in at least 30 genes implicated in this group of disorders. We discuss the genetics, and clinical, psychophysical, electrophysiological and retinal imaging characteristics of cone and cone-rod dystrophies, focusing particularly on four of the most common disease-associated genes: GUCA1A, PRPH2, ABCA4 and RPGR Additionally, we briefly review the current management of these disorders and the prospects for novel therapies.
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Affiliation(s)
- Jasdeep S Gill
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, London, UK
- Ophthalmology Department, University of California San Francisco School of Medicine, San Francisco, California, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
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40
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Disruption of RPGR protein interaction network is the common feature of RPGR missense variations that cause XLRP. Proc Natl Acad Sci U S A 2019; 116:1353-1360. [PMID: 30622176 DOI: 10.1073/pnas.1817639116] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Retinitis pigmentosa (RP) is an inherited retinal degenerative disease with severe vision impairment leading to blindness. About 10-15% of RP cases are caused by mutations in the RPGR gene, with RPGR mutations accounting for 70% of X-linked RP cases. The mechanism by which RPGR mutations cause photoreceptor cell dysfunction is not well understood. In this study, we show that the two isoforms of RPGR (RPGR1-19 and RPGRORF15) interact with endogenous PDE6D, INPP5E, and RPGRIP1L. The RPGR1-19 isoform contains two PDE6D binding sites with the C-terminal prenylation site being the predominant PDE6D binding site. The C terminus of RPGR1-19 that contains the prenylation site regulates its interaction with PDE6D, INPP5E, and RPGRIP1L. Only the RPGR1-19 isoform localizes to cilia in cultured RPE1 cells. Missense variations found in RPGR patients disrupt the interaction between RPGR isoforms and their endogenous interactors INPP5E, PDE6D, and RPGRIP1L. We evaluated a RPGR missense variation (M58K) found in a family with X-linked retinitis pigmentosa (XLRP) and show that this missense variation disrupts the interaction of RPGR isoforms with their endogenous interactors. The M58K variation also disrupts the ciliary localization of the RPGR1-19 isoform. Using this assay, we also show that some of the RPGR missense variants reported in the literature might not actually be disease causing. Our data establishes an in vitro assay that can be used to validate the potential pathogenicity of RPGR missense variants.
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Schlegel J, Hoffmann J, Röll D, Müller B, Günther S, Zhang W, Janise A, Vössing C, Fühler B, Neidhardt J, Khanna H, Lorenz B, Stieger K. Toward genome editing in X-linked RP-development of a mouse model with specific treatment relevant features. Transl Res 2019; 203:57-72. [PMID: 30213530 PMCID: PMC6294733 DOI: 10.1016/j.trsl.2018.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 08/16/2018] [Accepted: 08/16/2018] [Indexed: 01/06/2023]
Abstract
Genome editing represents a powerful tool to treat inherited disorders. Highly specific endonucleases induce a DNA double strand break near the mutant site, which is subsequently repaired by cellular DNA repair mechanisms that involve the presence of a wild type template DNA. In vivo applications of this strategy are still rare, in part due to the absence of appropriate animal models carrying human disease mutations and knowledge of the efficient targeting of endonucleases. Here we report the generation and characterization of a new mouse model for X-linked retinitis pigmentosa (XLRP) carrying a point mutation in the mutational hotspot exon ORF15 of the RPGR gene as well as a recognition site for the homing endonuclease I-SceI. Presence of the genomic modifications was verified at the RNA and protein levels. The mutant protein was observed at low levels. Optical coherence tomography studies revealed a slowly progressive retinal degeneration with photoreceptor loss starting at 9 months of age, paralleling the onset of functional deficits as seen in the electroretinogram. Early changes to the outer retinal bands can be used as biomarker during treatment applications. We further show for the first time efficient targeting using the I-SceI enzyme at the genomic locus in a proof of concept in photoreceptors following adeno-associated virus mediated gene transfer in vivo. Taken together, our studies not only provide a human-XLRP disease model but also act as a platform to design genome editing technology for retinal degenerative diseases using the currently available endonucleases.
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Affiliation(s)
- J Schlegel
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - J Hoffmann
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - D Röll
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - B Müller
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - S Günther
- Max-Planck-Institute for Heart and Lung Research, Bad Nauheim, Germany
| | - W Zhang
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - A Janise
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - C Vössing
- Human Genetics, Faculty of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany
| | - B Fühler
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - J Neidhardt
- Human Genetics, Faculty of Medicine and Health Sciences, University of Oldenburg, Oldenburg, Germany; Research Center Neurosensory Science, University Oldenburg, Oldenburg, Germany
| | - H Khanna
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts
| | - B Lorenz
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany
| | - K Stieger
- Department of Ophthalmology, Faculty of Medicine, Justus-Liebig-University Giessen, Giessen, Germany.
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Baehr W, Hanke-Gogokhia C, Sharif A, Reed M, Dahl T, Frederick JM, Ying G. Insights into photoreceptor ciliogenesis revealed by animal models. Prog Retin Eye Res 2018; 71:26-56. [PMID: 30590118 DOI: 10.1016/j.preteyeres.2018.12.004] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 12/10/2018] [Accepted: 12/18/2018] [Indexed: 12/11/2022]
Abstract
Photoreceptors are polarized neurons, with very specific subcellular compartmentalization and unique requirements for protein expression and trafficking. Each photoreceptor contains an outer segment, the site of photon capture that initiates vision, an inner segment that houses the biosynthetic machinery and a synaptic terminal for signal transmission to downstream neurons. Outer segments and inner segments are connected by a connecting cilium (CC), the equivalent of a transition zone (TZ) of primary cilia. The connecting cilium is part of the basal body/axoneme backbone that stabilizes the outer segment. This report will update the reader on late developments in photoreceptor ciliogenesis and transition zone formation, specifically in mouse photoreceptors, focusing on early events in photoreceptor ciliogenesis. The connecting cilium, an elongated and narrow structure through which all outer segment proteins and membrane components must traffic, functions as a gate that controls access to the outer segment. Here we will review genes and their protein products essential for basal body maturation and for CC/TZ genesis, sorted by phenotype. Emphasis is given to naturally occurring mouse mutants and gene knockouts that interfere with CC/TZ formation and ciliogenesis.
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Affiliation(s)
- Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA.
| | - Christin Hanke-Gogokhia
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Ali Sharif
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Michelle Reed
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Tiffanie Dahl
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Jeanne M Frederick
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
| | - Guoxin Ying
- Department of Ophthalmology and Visual Sciences, University of Utah Health Sciences, Salt Lake City, UT, 84132, USA
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The Role of the Microglial Cx3cr1 Pathway in the Postnatal Maturation of Retinal Photoreceptors. J Neurosci 2018; 38:4708-4723. [PMID: 29669747 DOI: 10.1523/jneurosci.2368-17.2018] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 03/22/2018] [Accepted: 04/10/2018] [Indexed: 11/21/2022] Open
Abstract
Microglia are the resident immune cells of the CNS, and their response to infection, injury and disease is well documented. More recently, microglia have been shown to play a role in normal CNS development, with the fractalkine-Cx3cr1 signaling pathway of particular importance. This work describes the interaction between the light-sensitive photoreceptors and microglia during eye opening, a time of postnatal photoreceptor maturation. Genetic removal of Cx3cr1 (Cx3cr1GFP/GFP ) led to an early retinal dysfunction soon after eye opening [postnatal day 17 (P17)] and cone photoreceptor loss (P30 onward) in mice of either sex. This dysfunction occurred at a time when fractalkine expression was predominantly outer retinal, when there was an increased microglial presence near the photoreceptor layer and increased microglial-cone photoreceptor contacts. Photoreceptor maturation and outer segment elongation was coincident with increased opsin photopigment expression in wild-type retina, while this was aberrant in the Cx3cr1GFP/GFP retina and outer segment length was reduced. A beadchip array highlighted Cx3cr1 regulation of genes involved in the photoreceptor cilium, a key structure that is important for outer segment elongation. This was confirmed with quantitative PCR with specific cilium-related genes, Rpgr and Rpgrip1, downregulated at eye opening (P14). While the overall cilium structure was unaffected, expression of Rpgr, Rpgrip1, and centrin were restricted to more proximal regions of the transitional zone. This study highlighted a novel role for microglia in postnatal neuronal development within the retina, with loss of fractalkine-Cx3cr1 signaling leading to an altered distribution of cilium proteins, failure of outer segment elongation and ultimately cone photoreceptor loss.SIGNIFICANCE STATEMENT Microglia are involved in CNS development and disease. This work highlights the role of microglia in postnatal development of the light-detecting photoreceptor neurons within the mouse retina. Loss of the microglial Cx3cr1 signaling pathway resulted in specific alterations in the cilium, a key structure in photoreceptor outer segment elongation. The distribution of key components of the cilium transitional zone, Rpgr, Rpgrip1, and centrin, were altered in retinae lacking Cx3cr1 with reduced outer segment length and cone photoreceptor death observed at later postnatal ages. This work identifies a novel role for microglia in the postnatal maturation of retinal photoreceptors.
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Rpgrip1 is required for rod outer segment development and ciliary protein trafficking in zebrafish. Sci Rep 2017; 7:16881. [PMID: 29203866 PMCID: PMC5715152 DOI: 10.1038/s41598-017-12838-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Accepted: 09/14/2017] [Indexed: 12/23/2022] Open
Abstract
Mutations in the RPGR-interacting protein 1 (RPGRIP1) gene cause recessive Leber congenital amaurosis (LCA), juvenile retinitis pigmentosa (RP) and cone-rod dystrophy. RPGRIP1 interacts with other retinal disease-causing proteins and has been proposed to have a role in ciliary protein transport; however, its function remains elusive. Here, we describe a new zebrafish model carrying a nonsense mutation in the rpgrip1 gene. Rpgrip1homozygous mutants do not form rod outer segments and display mislocalization of rhodopsin, suggesting a role for RPGRIP1 in rhodopsin-bearing vesicle trafficking. Furthermore, Rab8, the key regulator of rhodopsin ciliary trafficking, was mislocalized in photoreceptor cells of rpgrip1 mutants. The degeneration of rod cells is early onset, followed by the death of cone cells. These phenotypes are similar to that observed in LCA and juvenile RP patients. Our data indicate RPGRIP1 is necessary for rod outer segment development through regulating ciliary protein trafficking. The rpgrip1 mutant zebrafish may provide a platform for developing therapeutic treatments for RP patients.
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Huang D, Fletcher S, Wilton SD, Palmer N, McLenachan S, Mackey DA, Chen FK. Inherited Retinal Disease Therapies Targeting Precursor Messenger Ribonucleic Acid. Vision (Basel) 2017; 1:vision1030022. [PMID: 31740647 PMCID: PMC6836112 DOI: 10.3390/vision1030022] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 07/24/2017] [Accepted: 08/24/2017] [Indexed: 02/07/2023] Open
Abstract
Inherited retinal diseases are an extremely diverse group of genetically and phenotypically heterogeneous conditions characterized by variable maturation of retinal development, impairment of photoreceptor cell function and gradual loss of photoreceptor cells and vision. Significant progress has been made over the last two decades in identifying the many genes implicated in inherited retinal diseases and developing novel therapies to address the underlying genetic defects. Approximately one-quarter of exonic mutations related to human inherited diseases are likely to induce aberrant splicing products, providing opportunities for the development of novel therapeutics that target splicing processes. The feasibility of antisense oligomer mediated splice intervention to treat inherited diseases has been demonstrated in vitro, in vivo and in clinical trials. In this review, we will discuss therapeutic approaches to treat inherited retinal disease, including strategies to correct splicing and modify exon selection at the level of pre-mRNA. The challenges of clinical translation of this class of emerging therapeutics will also be discussed.
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Affiliation(s)
- Di Huang
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Sue Fletcher
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Steve D. Wilton
- Molecular Therapy Laboratory, Murdoch University, Murdoch 6150, Australia
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Norman Palmer
- Perron Institute, 4th Floor A Block, Queen Elizabeth II Medical Centre, Verdun Street, Nedlands 6009, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
| | - David A. Mackey
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
| | - Fred K. Chen
- Centre for Ophthalmology and Visual Science (Incorporating Lions Eye Institute), The University of Western Australia, Nedlands 6009, Australia
- Department of Ophthalmology, Royal Perth Hospital, Perth 6000, Australia
- Correspondence: ; Tel.: +61-8-9381-0817
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Disease mechanisms of X-linked retinitis pigmentosa due to RP2 and RPGR mutations. Biochem Soc Trans 2017; 44:1235-1244. [PMID: 27911705 DOI: 10.1042/bst20160148] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 08/16/2016] [Accepted: 08/18/2016] [Indexed: 01/24/2023]
Abstract
Photoreceptor degeneration is the prominent characteristic of retinitis pigmentosa (RP), a heterogeneous group of inherited retinal dystrophies resulting in blindness. Although abnormalities in many pathways can cause photoreceptor degeneration, one of the most important causes is defective protein transport through the connecting cilium, the structure that connects the biosynthetic inner segment with the photosensitive outer segment of the photoreceptors. The majority of patients with X-linked RP have mutations in the retinitis pigmentosa GTPase regulator (RPGR) or RP2 genes, the protein products of which are both components of the connecting cilium and associated with distinct mechanisms of protein delivery to the outer segment. RP2 and RPGR proteins are associated with severe diseases ranging from classic RP to atypical forms. In this short review, we will summarise current knowledge generated by experimental studies and knockout animal models, compare and discuss the prominent hypotheses about the two proteins' functions in retinal cell biology.
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Tee JJL, Carroll J, Webster AR, Michaelides M. Quantitative Analysis of Retinal Structure Using Spectral-Domain Optical Coherence Tomography in RPGR-Associated Retinopathy. Am J Ophthalmol 2017; 178:18-26. [PMID: 28322733 PMCID: PMC5451208 DOI: 10.1016/j.ajo.2017.03.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 03/08/2017] [Accepted: 03/09/2017] [Indexed: 01/29/2023]
Abstract
Purpose To quantify retinal structure and progression using spectral-domain optical coherence tomography (SDOCT) in patients with retinitis pigmentosa (RP) associated with retinitis pigmentosa GTPase regulator gene (RPGR) mutations. Design Retrospective observational case series. Methods Setting: Moorfields Eye Hospital, London, United Kingdom. Subjects: Both eyes of 32 patients. SDOCT follow-up period of >1 year (3.1 ± 1.4 years). Main Outcome Measures: Ellipsoid zone (EZ) width (EZW) and outer nuclear layer (ONL) and inner retinal layer (IRL) thickness measurements. Progression rates, interocular symmetry, and association with age and genotype were investigated. Results Significant differences were observed between baseline and final measurements of EZW and ONL thickness, but not for IRL thickness. Baseline and final EZWs were 2438 ± 1646 μm and 1901 ± 1423 μm for right eyes (P < .0001); 2420 ± 1758 μm and 1922 ± 1482 μm for left eyes (P < .0001). EZW constriction rates were 176.6 ± 130.1 μm/year and 173.1 ± 146.8 μm/year for right and left eyes. ONL thinning rates were 2.58 ± 2.85 μm/year and 2.52 ± 3.54 μm/year for right and left eyes. Interocular differences in EZW and ONL progression were not significant (P = .8609 and P = .6735, respectively). Strong correlations were found between EZW constriction rates of right and left eyes (rs = 0.627, P = .0002) and between EZW constriction and baseline EZW (rs = 0.714, P < .0001). There was moderate negative correlation between EZW constriction and age (rs = −0.532, P < .0001). Correlation between ONL thinning and age was not significant, as were differences between EZW and ONL progression rates with respect to genotype. Conclusions This study provides SDOCT progression rates for RPGR-associated RP. There is overall interocular symmetry with implications for future treatment trials where 1 eye could serve as a control.
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Affiliation(s)
- James J L Tee
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom.
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48
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May-Simera H, Nagel-Wolfrum K, Wolfrum U. Cilia - The sensory antennae in the eye. Prog Retin Eye Res 2017; 60:144-180. [PMID: 28504201 DOI: 10.1016/j.preteyeres.2017.05.001] [Citation(s) in RCA: 96] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 05/04/2017] [Accepted: 05/08/2017] [Indexed: 12/21/2022]
Abstract
Cilia are hair-like projections found on almost all cells in the human body. Originally believed to function merely in motility, the function of solitary non-motile (primary) cilia was long overlooked. Recent research has demonstrated that primary cilia function as signalling hubs that sense environmental cues and are pivotal for organ development and function, tissue hoemoestasis, and maintenance of human health. Cilia share a common anatomy and their diverse functional features are achieved by evolutionarily conserved functional modules, organized into sub-compartments. Defects in these functional modules are responsible for a rapidly growing list of human diseases collectively termed ciliopathies. Ocular pathogenesis is common in virtually all classes of syndromic ciliopathies, and disruptions in cilia genes have been found to be causative in a growing number of non-syndromic retinal dystrophies. This review will address what is currently known about cilia contribution to visual function. We will focus on the molecular and cellular functions of ciliary proteins and their role in the photoreceptor sensory cilia and their visual phenotypes. We also highlight other ciliated cell types in tissues of the eye (e.g. lens, RPE and Müller glia cells) discussing their possible contribution to disease progression. Progress in basic research on the cilia function in the eye is paving the way for therapeutic options for retinal ciliopathies. In the final section we describe the latest advancements in gene therapy, read-through of non-sense mutations and stem cell therapy, all being adopted to treat cilia dysfunction in the retina.
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Affiliation(s)
- Helen May-Simera
- Institute of Molecular Physiology, Cilia Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Kerstin Nagel-Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany
| | - Uwe Wolfrum
- Institute of Molecular Physiology, Molecular Cell Biology, Johannes Gutenberg-Universität Mainz, 55099 Mainz, Germany.
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Charng J, Cideciyan AV, Jacobson SG, Sumaroka A, Schwartz SB, Swider M, Roman AJ, Sheplock R, Anand M, Peden MC, Khanna H, Heon E, Wright AF, Swaroop A. Variegated yet non-random rod and cone photoreceptor disease patterns in RPGR-ORF15-associated retinal degeneration. Hum Mol Genet 2016; 25:5444-5459. [PMID: 27798110 PMCID: PMC6078602 DOI: 10.1093/hmg/ddw361] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 12/13/2022] Open
Abstract
Mutations in the ORF15 exon of the RPGR gene cause a common form of X-linked retinitis pigmentosa, which often results in severe loss of vision. In dogs and mice, gene augmentation therapy has been shown to arrest the progressive degeneration of rod and cone photoreceptors. However, the distribution of potentially treatable photoreceptors across the human retinas and the rate of degeneration are not known. Here, we have defined structural and functional features of the disease in 70 individuals with ORF15 mutations. We also correlated the features observed in patients with those of three Rpgr-mutant (Rpgr-ko, Rd9, and Rpgr-cko) mice. In patients, there was pronounced macular disease. Across the retina, rod and cone dysfunction showed a range of patterns and a spectrum of severity between individuals, but a high symmetry was observed between eyes of each individual. Genotype was not related to disease expression. In the Rpgr-ko mice, there were intra-retinal differences in rhodopsin and cone opsin trafficking. In Rd9 and Rpgr-cko mice, retinal degeneration showed inter-ocular symmetry. Longitudinal results in patients revealed localized rod and cone dysfunction with progression rates of 0.8 to 1.3 log per decade in sensitivity loss. Relatively retained rod and cone photoreceptors in mid- and far-peripheral temporal-inferior and nasal-inferior visual field regions should be good targets for future localized gene therapies in patients.
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Affiliation(s)
- Jason Charng
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Sharon B. Schwartz
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, PA, USA
| | - Manisha Anand
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, MA, USA
| | - Marc C. Peden
- Retina Associates of Florida, Tampa, Florida, FL, USA
| | - Hemant Khanna
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, MA, USA
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Canada
| | - Alan F. Wright
- MRC Human Genetics Unit, MRC IGMM, University of Edinburgh, Edinburgh, Scotland, UK
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, MD, USA
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50
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Dutta N, Seo S. RPGR, a prenylated retinal ciliopathy protein, is targeted to cilia in a prenylation- and PDE6D-dependent manner. Biol Open 2016; 5:1283-9. [PMID: 27493202 PMCID: PMC5051646 DOI: 10.1242/bio.020461] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
RPGR (retinitis pigmentosa GTPase regulator) is a ciliary protein associated with several forms of inherited retinal degenerative diseases. PDE6D is a ubiquitously expressed prenyl-binding protein and involved in ciliary targeting of prenylated proteins. The current working model for the RPGR function depicts that RPGR acts as a scaffold protein to recruit cargo-loaded PDE6D to primary cilia. Here, we present evidence demonstrating an alternative relationship between RPGR and PDE6D, in which RPGR is a cargo of PDE6D for ciliary targeting. We found that the constitutive isoform of RPGR, which is prenylated, requires prenylation for its ciliary localization. We also found that there are at least two independent ciliary targeting signals in RPGR: one within the N-terminal region that contains the RCC1-like domain and the other near the prenylation site at the C-terminus. Ablation of PDE6D blocked ciliary targeting of RPGR. Our study indicates that prenylated RPGR is one of the cargos of PDE6D for ciliary trafficking and provides insight into the mechanisms by which RPGR is targeted to cilia. Summary: RPGR is a ciliary protein that functions as a scaffold to recruit cargo-loaded PDE6D to cilia. Our study shows that RPGR is also a cargo of PDE6D.
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Affiliation(s)
- Nirmal Dutta
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, IA 52242, USA
| | - Seongjin Seo
- Department of Ophthalmology and Visual Sciences, University of Iowa College of Medicine, Iowa City, IA 52242, USA
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