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Lando L, Borooah S. Late-Onset Retinal Degeneration: Clinical Perspectives. Clin Ophthalmol 2022; 16:3225-3246. [PMID: 36204011 PMCID: PMC9531619 DOI: 10.2147/opth.s362691] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 09/13/2022] [Indexed: 12/03/2022] Open
Abstract
Late-onset retinal degeneration (L-ORD) is a type of retinal dystrophy marked by nyctalopia and subretinal pigment epithelium deposits, which eventually promote retinal atrophy with final visual compromise. L-ORD may also present with changes in the anterior segment, notably long anterior zonules and iris atrophy, distinguishing it from other inherited eye conditions. Although it can clinically simulate age-related macular degeneration, L-ORD has a different course of progression and prognosis, requiring adequate diagnosis for patient counseling. This review summarizes the main clinical, genetic, pathophysiological, diagnostic, and therapeutic aspects of L-ORD to help ophthalmologists identify and manage this rare ocular disease.
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Affiliation(s)
- Leonardo Lando
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada
| | - Shyamanga Borooah
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
- Correspondence: Shyamanga Borooah, Shiley Eye Institute, University of California San Diego, 9415 Campus Point Drive, La Jolla, CA, 92093, USA, Email
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2
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Can metformin modulate the retinal degenerative changes in a rat model of retinitis pigmentosa? Tissue Cell 2022; 76:101786. [DOI: 10.1016/j.tice.2022.101786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2021] [Revised: 02/18/2022] [Accepted: 03/13/2022] [Indexed: 11/21/2022]
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Wu AL, Wang JP, Tseng YJ, Liu L, Kang YC, Chen KJ, Chao AN, Yeh LK, Chen TL, Hwang YS, Wu WC, Lai CC, Wang NK. MULTIMODAL IMAGING OF MOSAIC RETINOPATHY IN CARRIERS OF HEREDITARY X-LINKED RECESSIVE DISEASES. Retina 2018; 38:1047-1057. [PMID: 28376043 DOI: 10.1097/iae.0000000000001629] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate the clinical features in carriers of X-linked retinitis pigmentosa, X-linked ocular albinism, and choroideremia (CHM) using multimodal imaging and to assess their diagnostic value in these three mosaic retinopathies. METHODS We prospectively examined 14 carriers of 3 X-linked recessive disorders (X-linked retinitis pigmentosa, X-linked ocular albinism, and CHM). Details of abnormalities of retinal morphology were evaluated using fundus photography, fundus autofluorescence (FAF) imaging, and spectral domain optical coherence tomography. RESULTS In six X-linked retinitis pigmentosa carriers, fundus appearance varied from unremarkable to the presence of tapetal-like reflex and pigmentary changes. On FAF imaging, all carriers exhibited a bright radial reflex against a dark background. By spectral domain optical coherence tomography, loss of the ellipsoid zone in the macula was observed in 3 carriers (50%). Regarding the retinal laminar architecture, 4 carriers (66.7%) showed thinning of the outer nuclear layer and a dentate appearance of the outer plexiform layer. All five X-linked ocular albinism carriers showed a characteristic mud-splatter patterned fundus, dark radial streaks against a bright background on FAF imaging, and a normal-appearing retinal structure by spectral domain optical coherence tomography imaging. Two of the 3 CHM carriers (66.7%) showed a diffuse moth-eaten appearance of the fundus, and all 3 showed irregular hyper-FAF and hypo-FAF spots throughout the affected area. In the CHM carriers, the structural changes observed by spectral domain optical coherence tomography imaging were variable. CONCLUSION Our findings in an Asian cohort suggest that FAF imaging is a practical diagnostic test for differentiating X-linked retinitis pigmentosa, X-linked ocular albinism, and CHM carriers. Wide-field FAF is an easy and helpful adjunct to testing for the correct diagnosis and identification of lyonization in carriers of these three mosaic retinopathies.
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Affiliation(s)
- An-Lun Wu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Jung-Pan Wang
- Department of Orthopaedics and Traumatology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Yun-Ju Tseng
- Herbert Irving Comprehensive Cancer Center, Columbia University, New York, New York
| | - Laura Liu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yu-Chuan Kang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Kuan-Jen Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - An-Ning Chao
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Lung-Kun Yeh
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Tun-Lu Chen
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Yih-Shiou Hwang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Chi Wu
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Chi-Chun Lai
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Nan-Kai Wang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan, Taiwan.,College of Medicine, Chang Gung University, Taoyuan, Taiwan
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Fu X, Huu VAN, Duan Y, Kermany DS, Valentim CCS, Zhang R, Zhu J, Zhang CL, Sun X, Zhang K. Clinical applications of retinal gene therapies. PRECISION CLINICAL MEDICINE 2018; 1:5-20. [PMID: 35694125 PMCID: PMC8982485 DOI: 10.1093/pcmedi/pby004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 03/27/2018] [Accepted: 04/03/2018] [Indexed: 02/05/2023] Open
Abstract
Retinal degenerative diseases are a major cause of blindness. Retinal gene therapy is a
trail-blazer in the human gene therapy field, leading to the first FDA approved gene
therapy product for a human genetic disease. The application of Clustered Regularly
Interspaced Short Palindromic Repeat/Cas9 (CRISPR/Cas9)-mediated gene editing technology
is transforming the delivery of gene therapy. We review the history, present, and future
prospects of retinal gene therapy.
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Affiliation(s)
- Xin Fu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Viet Anh Nguyen Huu
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Yaou Duan
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Daniel S Kermany
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Carolina C S Valentim
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Runze Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Jie Zhu
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Charlotte L Zhang
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
| | - Xiaodong Sun
- Shanghai Key Laboratory of Ocular Fundus Diseases, Shanghai General Hospital, Shanghai Jiaodong University, Shanghai, China
| | - Kang Zhang
- Guangzhou Women and Children’s Medical Center, Guangzhou Medical University, Guangzhou, China
- Shiley Eye Institute, Institute for Engineering in Medicine, Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, USA
- Molecular Medicine Research Center, West China Hospital, Sichuan University, Chengdu, China
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Jacobson SG, McGuigan DB, Sumaroka A, Roman AJ, Gruzensky ML, Sheplock R, Palma J, Schwartz SB, Aleman TS, Cideciyan AV. Complexity of the Class B Phenotype in Autosomal Dominant Retinitis Pigmentosa Due to Rhodopsin Mutations. Invest Ophthalmol Vis Sci 2016; 57:4847-4858. [PMID: 27654411 PMCID: PMC5032913 DOI: 10.1167/iovs.16-19890] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose Previously, patients with RHO mutations and a class A phenotype were found to have severe early-onset loss of rod function, whereas patients with a class B phenotype retained rod function at least in certain retinal regions. Here class B patients were studied at different disease stages to understand the topographic details of the phenotype in preparation for therapies of this regionalized retinopathy. Methods A cohort of patients with RHO mutations and class B phenotype (n = 28; ages 10–80 years) were studied with rod and cone perimetry and optical coherence tomography (OCT). Results At least three components of the phenotype were identified in these cross-sectional studies. Patients could have hemifield dysfunction, pericentral loss of function, or a diffuse rod sensitivity loss across the visual field. Combinations of these different patterns were also found. Colocalized photoreceptor layer thicknesses were in agreement with the psychophysical results. Conclusions These disorders with regional retinal variation of severity require pre-evaluations before enrollment into clinical trials to seek answers to questions about where in the retina would be appropriate to deliver focal treatments, and, for retina-wide treatment strategies, where in the retina should be monitored for therapeutic efficacy (or safety).
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Affiliation(s)
- Samuel G Jacobson
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - David B McGuigan
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alexander Sumaroka
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Alejandro J Roman
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Michaela L Gruzensky
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Rebecca Sheplock
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Judy Palma
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Sharon B Schwartz
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Tomas S Aleman
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Artur V Cideciyan
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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Thompson DA, Khan NW, Othman MI, Chang B, Jia L, Grahek G, Wu Z, Hiriyanna S, Nellissery J, Li T, Khanna H, Colosi P, Swaroop A, Heckenlively JR. Rd9 is a naturally occurring mouse model of a common form of retinitis pigmentosa caused by mutations in RPGR-ORF15. PLoS One 2012; 7:e35865. [PMID: 22563472 PMCID: PMC3341386 DOI: 10.1371/journal.pone.0035865] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2012] [Accepted: 03/27/2012] [Indexed: 11/18/2022] Open
Abstract
Animal models of human disease are an invaluable component of studies aimed at understanding disease pathogenesis and therapeutic possibilities. Mutations in the gene encoding retinitis pigmentosa GTPase regulator (RPGR) are the most common cause of X-linked retinitis pigmentosa (XLRP) and are estimated to cause 20% of all retinal dystrophy cases. A majority of RPGR mutations are present in ORF15, the purine-rich terminal exon of the predominant splice-variant expressed in retina. Here we describe the genetic and phenotypic characterization of the retinal degeneration 9 (Rd9) strain of mice, a naturally occurring animal model of XLRP. Rd9 mice were found to carry a 32-base-pair duplication within ORF15 that causes a shift in the reading frame that introduces a premature-stop codon. Rpgr ORF15 transcripts, but not protein, were detected in retinas from Rd9/Y male mice that exhibited retinal pathology, including pigment loss and slowly progressing decrease in outer nuclear layer thickness. The levels of rhodopsin and transducin in rod outer segments were also decreased, and M-cone opsin appeared mislocalized within cone photoreceptors. In addition, electroretinogram (ERG) a- and b-wave amplitudes of both Rd9/Y male and Rd9/Rd9 female mice showed moderate gradual reduction that continued to 24 months of age. The presence of multiple retinal features that correlate with findings in individuals with XLRP identifies Rd9 as a valuable model for use in gaining insight into ORF15-associated disease progression and pathogenesis, as well as accelerating the development and testing of therapeutic strategies for this common form of retinal dystrophy.
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Affiliation(s)
- Debra A. Thompson
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Naheed W. Khan
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Mohammad I. Othman
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Bo Chang
- Jackson Laboratory, Bar Harbor, Maine, United States of America
| | - Lin Jia
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Garrett Grahek
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Zhijian Wu
- Neurobiology-Neurodegeneration & Repair laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Suja Hiriyanna
- Neurobiology-Neurodegeneration & Repair laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Jacob Nellissery
- Neurobiology-Neurodegeneration & Repair laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Tiansen Li
- Neurobiology-Neurodegeneration & Repair laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hemant Khanna
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Peter Colosi
- Neurobiology-Neurodegeneration & Repair laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail: (AS); (JRH)
| | - John R. Heckenlively
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- * E-mail: (AS); (JRH)
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A novel mutation (Cys83Tyr) in the second zinc finger of NR2E3 in enhanced S-cone syndrome. Graefes Arch Clin Exp Ophthalmol 2010; 249:201-8. [PMID: 20725840 DOI: 10.1007/s00417-010-1482-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 07/25/2010] [Accepted: 07/26/2010] [Indexed: 10/19/2022] Open
Abstract
BACKGROUND Enhanced S-cone syndrome (ESCS) is an autosomal recessive retinal disorder characterized by an increased number of S-cones over L/M cones and rods. Mutations in the NR2E3 gene, encoding a photoreceptor-specific nuclear receptor, are identified in patients with ESCS. The purpose of this study is to report the ophthalmic features of a 25-year-old Portuguese male with a typical ESCS phenotype and a novel homozygous NR2E3 mutation. METHODS The patient underwent a detailed ophthalmic examination including fundus photography, fluorescein angiography (FAF), fundus autofluorescence imaging (FAI), and spectral domain optical coherence tomography (SD-OCT). Full-field electroretinography (ERG), S-cone ERG, and multifocal ERG were performed. Mutation screening of the NR2E3 gene was performed with polymerase chain reaction amplification and direct sequencing. RESULTS The patient had poor visual acuity but good color vision. Funduscopy showed degenerative changes from the vascular arcades to the midperipheral retina. The SD-OCT revealed macular schisis and cystoid changes that had no fluorescein leakage. The posterior pole showed diffusely increased autofluorescence compared with eccentric areas in both eyes. International-standard full-field ERG showed the typical pathognomonic changes associated with ESCS and the short-wavelength flash ERG was simplified, delayed, and similar to the standard photopic flash ERG. Multifocal ERG showed widespread delay and reduction. Genetic analysis revealed a novel homozygous mutation (p.C83Y), which resides in the second zinc finger of the DNA-binding domain. CONCLUSIONS This homozygous mutation is likely to affect binding to target DNA sites, resulting in a non-functional behavior of NR2E3 protein. It is associated with a typical form of ESCS with a nondetectable rod response and reduced/delayed mfERG responses at all eccentricities.
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Cideciyan AV. Leber congenital amaurosis due to RPE65 mutations and its treatment with gene therapy. Prog Retin Eye Res 2010; 29:398-427. [PMID: 20399883 DOI: 10.1016/j.preteyeres.2010.04.002] [Citation(s) in RCA: 178] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Leber congenital amaurosis (LCA) is a rare hereditary retinal degeneration caused by mutations in more than a dozen genes. RPE65, one of these mutated genes, is highly expressed in the retinal pigment epithelium where it encodes the retinoid isomerase enzyme essential for the production of chromophore which forms the visual pigment in rod and cone photoreceptors of the retina. Congenital loss of chromophore production due to RPE65-deficiency together with progressive photoreceptor degeneration cause severe and progressive loss of vision. RPE65-associated LCA recently gained recognition outside of specialty ophthalmic circles due to early success achieved by three clinical trials of gene therapy using recombinant adeno-associated virus (AAV) vectors. The trials were built on multitude of basic, pre-clinical and clinical research defining the pathophysiology of the disease in human subjects and animal models, and demonstrating the proof-of-concept of gene (augmentation) therapy. Substantial gains in visual function of clinical trial participants provided evidence for physiologically relevant biological activity resulting from a newly introduced gene. This article reviews the current knowledge on retinal degeneration and visual dysfunction in animal models and human patients with RPE65 disease, and examines the consequences of gene therapy in terms of improvement of vision reported.
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Affiliation(s)
- Artur V Cideciyan
- Scheie Eye Institute, University of Pennsylvania, 51 North 39th St, Philadelphia, PA 19104, USA.
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Abstract
PURPOSE The purpose of this study is to document the appearance of macular toxoplasmosis scars with the high-resolution cross-sectional retinal imaging technique of optical coherence tomography (OCT) and investigate whether a correlation exists between the morphology of the toxoplasmosis scars, the OCT images, and visual acuity. METHODS In this retrospective observational case series, fundus photos were taken of the macular lesions that were also documented by OCT. Photos were digitized for the purpose of sizing lesions. All images were classified by the authors. RESULTS There were 10 consecutive patients (13 eyes) whose average age is 13.0 years. Macular lesions ranged from 1.6 mm2 to 20.2 mm2. OCT features included retinal thinning, retinal pigment epithelial hyperreflectivity, excavation, intraretinal cysts, and fibrosis. Patients with better than expected vision had either parafoveal lesions or an intact neurosensory layer. CONCLUSION The most characteristic OCT features in this young population were prominent retinal thinning, retinal pigment epithelium hyperreflectivity, and excavation of varying severity. OCT imaging is helpful in explaining better than expected vision.
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Hugosson T, Gränse L, Ponjavic V, Andréasson S. Macular dysfunction and morphology in spinocerebellar ataxia type 7 (SCA 7). Ophthalmic Genet 2009; 30:1-6. [PMID: 19172503 DOI: 10.1080/13816810802454081] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
PURPOSE To characterize the clinical phenotype regarding retinal function and macular appearance in patients with spinocerebellar ataxia type 7 (SCA 7), with an emphasis on electrophysiological findings. METHODS Three patients from two Swedish families were given an ophthalmological examination including visual acuity, fundus inspection, Farnsworth's color vision test, Goldmann perimetry, full-field electroretinography (full-field ERG), multifocal electroretinography (mfERG) and optical coherence tomography (OCT). DNA was analyzed with polymerase chain reaction for CAG trinucleotide expansion repeats in the SCA 7 gene. RESULTS Molecular analysis demonstrated abnormally expanded CAG repeats in the gene for SCA 7, which encodes the protein ataxin-7, thus confirming the diagnosis SCA 7. In the oldest patient very discreet pigmentary changes in the maculae were found, but with that exception the patients had a normal ophthalmoscopic fundus appearance and OCT demonstrated only minor changes. MfERG indicated predominantly central involvement, especially in the early disease stages, which in pace with disease progression extended from the center to the more peripheral areas. Full-field ERG in the oldest patient demonstrated bilaterally distinctly prolonged 30-Hz flicker implicit time, verifying widespread cone photoreceptor degeneration. CONCLUSIONS The patients with genetically confirmed SCA 7 presented an early macular dysfunction, preceding any signs of abnormalities in fundus appearance. According to the electrophysiological findings the primary dysfunction involves the cone photoreceptors in the foveal region, however in an older patient involvement of cone photoreceptors throughout the retina was verified. This is in accordance with the theory that ataxin-7 interacts with CRX transcription, since it is known that mutations in the CRX gene cause cone-rod dystrophy.
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Affiliation(s)
- Therése Hugosson
- Department of Ophthalmology, Central Hospital, Kristianstad, Sweden.
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Shu X, Black GC, Rice JM, Hart-Holden N, Jones A, O'Grady A, Ramsden S, Wright AF. RPGRmutation analysis and disease: an update. Hum Mutat 2007; 28:322-8. [PMID: 17195164 DOI: 10.1002/humu.20461] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene are the most common single cause of retinitis pigmentosa, accounting for up to 15 to 20% of cases in Caucasians. A total of 240 different RPGR mutations have been reported, including 24 novel ones in this work, which are associated with X-linked retinitis pigmentosa (XLRP) (95%), cone, cone-rod dystrophy, or atrophic macular atrophy (3%), and syndromal retinal dystrophies with ciliary dyskinesia and hearing loss (2%). All disease-causing mutations occur in one or more RPGR isoforms containing the carboxyl-terminal exon open reading frame 15 (ORF15), which are widely expressed but show their highest expression in the connecting cilia of rod and cone photoreceptors. Of reported RPGR mutations, 55% occur in a glutamic acid-rich domain within exon ORF15, which accounts for only 31% of the protein. RPGR forms complexes with a variety of other proteins and appears to have a role in microtubular organization and transport between photoreceptor inner and outer segments.
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Affiliation(s)
- Xinhua Shu
- Medical Research Council Human Genetics Unit, Edinburgh, United Kingdom
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Adamian M, Pawlyk BS, Hong DH, Berson EL. Rod and cone opsin mislocalization in an autopsy eye from a carrier of X-linked retinitis pigmentosa with a Gly436Asp mutation in the RPGR gene. Am J Ophthalmol 2006; 142:515-8. [PMID: 16935610 DOI: 10.1016/j.ajo.2006.03.061] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2005] [Revised: 03/27/2006] [Accepted: 03/27/2006] [Indexed: 10/24/2022]
Abstract
PURPOSE We investigated whether opsin mislocalization occurs in photoreceptors in a female carrier of X-linked retinitis pigmentosa with a Gly436Asp mutation in the retinitis pigmentosa GTPase regulator gene (RPGR). DESIGN Histologic findings in autopsy eyes from a carrier were compared with those from a normal female. METHODS Frozen retinal sections from the periphery of one eye of the carrier and the normal were stained with antibodies against either human red or green opsins, blue cone opsin, or rhodopsin and labeled with fluorochrome conjugated secondary antibodies. Cell nuclei were counterstained with Hoechst dye. Fellow eyes were evaluated with light microscopy. RESULTS Fluorescent labeling showed mislocalized cone and rod opsins in photoreceptor cells only in the carrier. The carrier also showed some loss of photoreceptor nuclei. CONCLUSIONS A defect in trafficking of opsins to outer segments exists in a carrier with the RPGR Gly436Asp mutation.
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Affiliation(s)
- Michael Adamian
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts 02114, USA
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