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Roshandel D, Lamey TM, Charng J, Heath Jeffery RC, McLaren TL, Thompson JA, De Roach JN, McLenachan S, Mackey DA, Chen FK. Microperimetry and Adaptive Optics Imaging Reveal Localized Functional and Structural Changes in Asymptomatic RPGR Mutation Carriers. Invest Ophthalmol Vis Sci 2023; 64:3. [PMID: 36607619 PMCID: PMC9836009 DOI: 10.1167/iovs.64.1.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purpose Female carriers of RPGR mutations demonstrate no significant retinal dysfunction or structural change despite a characteristic tapetal-like reflex. In this study, we examined localized changes of pointwise sensitivity (PWS) and cone density (CD) using microperimetry (MP) and adaptive optics (AO) imaging in female carriers of RPGR mutations. Methods In this cross-sectional case-control study, MP (MAIA, 10-2 test grid) and AO imaging (rtx1) were performed in female carriers of RPGR mutations and unrelated age-matched healthy controls. PWS at 68 loci located 1 degree to 9 degrees away from the preferred retinal locus and CD at 12 loci located 1 degree to 3 degrees away from the foveal center were measured. Severity of defect was defined by standard deviation (SD) from age-matched healthy control means: normal (<1 SD from normal average), moderate defect (1-2 SD from normal average), and severe defect (>2 SD from normal average). Results Twelve patients from seven unrelated families were enrolled. Seven patients were asymptomatic, 5 of whom had visual acuity 20/20 or better in both eyes. PWS and CD were available in 12 and 8 patients, respectively. Severe PWS and CD defect in at least 1 test location was observed in 10 of 12 patients and 7 of 8 patients, respectively. Among the five asymptomatic patients who had normal visual acuity, severe PWS and CD defects were observed in three of five and four of five patients, respectively. Conclusions MP and AO imaging revealed early functional and structural changes in asymptomatic RPGR mutation carriers and should be considered in clinical assessment of these patients.
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Affiliation(s)
- Danial Roshandel
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - Tina M. Lamey
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Jason Charng
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Department of Optometry, School of Allied Health, University of Western Australia, Western Australia, Australia
| | - Rachael C. Heath Jeffery
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Terri L. McLaren
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,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
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Samuel McLenachan
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia
| | - David A. Mackey
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia
| | - Fred K. Chen
- Centre for Ophthalmology and Visual Science, The University of Western Australia, Nedlands, Western Australia, Australia,Ocular Tissue Engineering Laboratory, Lions Eye Institute, Nedlands, Western Australia, Australia,Australian Inherited Retinal Disease Registry and DNA Bank, Department of Medical Technology and Physics, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia,Department of Optometry, School of Allied Health, University of Western Australia, Western Australia, Australia,Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia,Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
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2
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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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3
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A novel mutation of the RPGR gene in a Chinese X-linked retinitis pigmentosa family and possible involvement of X-chromosome inactivation. Eye (Lond) 2021; 35:1688-1696. [PMID: 32839555 PMCID: PMC8169654 DOI: 10.1038/s41433-020-01150-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 07/14/2020] [Accepted: 08/13/2020] [Indexed: 01/30/2023] Open
Abstract
OBJECTIVES The objective of this study is to investigate the molecular mechanisms and genotype-phenotype correlations of a Chinese family with X-linked retinitis pigmentosa (XLRP). METHODS A four-generation family with a total of 41 individuals including 7 affected males was recruited. All subjects in this pedigree underwent a complete ophthalmic examination. Targeted capture and next-generation sequencing were performed on the proband using a multigene panel containing 57 known causative genes of retinitis pigmentosa (RP), including RP1, RP2, RPGR, RHO, PRPH2, CRB1 among others. All variants were verified in the remaining family members by polymerase chain reaction amplification and Sanger sequencing. Blood DNA was used for X-chromosome inactivation analysis in female carriers. RESULTS All the affected individuals were diagnosed with RP. The affected males showed symptoms from the first decade, while the female carriers had onset in the second decade or later. A frameshift mutation c.345_348delTGAA in the RPGR gene was identified in all affected males and female carriers. By XCI analysis, we found that there was little correlation between their phenotype and the methylation status of their X chromosomes. CONCLUSIONS A novel mutation c.345_348delTGAA of the RPGR gene was identified, expanding the spectrum of RPGR mutations causing XLRP. In this pedigree, the phenotype extended to female carriers, in whom RP was milder and its onset delayed compared to hemizygous males. Although lack of strong correlation between X-inactivation and the severity of the disease, the milder, variable effects in female carriers still could reflect X-inactivation patterns in the retina of each individual.
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4
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Talib M, van Schooneveld MJ, Van Cauwenbergh C, Wijnholds J, Ten Brink JB, Florijn RJ, Schalij-Delfos NE, Dagnelie G, van Genderen MM, De Baere E, Meester-Smoor MA, De Zaeytijd J, Cremers FPM, van den Born LI, Thiadens AA, Hoyng CB, Klaver CC, Leroy BP, Bergen AA, Boon CJF. The Spectrum of Structural and Functional Abnormalities in Female Carriers of Pathogenic Variants in the RPGR Gene. Invest Ophthalmol Vis Sci 2019; 59:4123-4133. [PMID: 30105367 DOI: 10.1167/iovs.17-23453] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to investigate the phenotype and long-term clinical course of female carriers of RPGR mutations. Methods This was a retrospective cohort study of 125 heterozygous RPGR mutation carriers from 49 families. Results Eighty-three heterozygotes were from retinitis pigmentosa (RP) pedigrees, 37 were from cone-/cone-rod dystrophy (COD/CORD) pedigrees, and 5 heterozygotes were from pedigrees with mixed RP/CORD or unknown diagnosis. Mutations were located in exon 1-14 and in ORF15 in 42 of 125 (34%) and 83 of 125 (66%) subjects, respectively. The mean age at the first examination was 34.4 years (range, 2.1 to 86.0 years). The median follow-up time in heterozygotes with longitudinal data (n = 62) was 12.2 years (range, 1.1 to 52.2 years). Retinal pigmentary changes were present in 73 (58%) individuals. Visual symptoms were reported in 51 (40%) cases. Subjects with both symptoms and pigmentary fundus changes were older than the other heterozygotes (P = 0.01) and had thinner foveal outer retinas (P = 0.006). Complete expression of the RP or CORD phenotype was observed in 29 (23%) heterozygotes, although usually in milder forms than in affected male relatives. Best-corrected visual acuity (BCVA) was <20/40 and <20/400 in at least one eye in 45 of 116 (39%) and 11 of 116 (9%) heterozygotes, respectively. Myopia was observed in 74 of 101 (73%) subjects and was associated with lower BCVA (P = 0.006). Increasing age was associated with lower BCVA (P = 0.002) and decreasing visual field size (P = 0.012; I4e isopter). Conclusions RPGR mutations lead to a phenotypic spectrum in female carriers, with myopia as a significantly aggravating factor. Complete disease expression is observed in some individuals, who may benefit from future (gene) therapeutic options.
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Affiliation(s)
- Mays Talib
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Caroline Van Cauwenbergh
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium.,Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Jan Wijnholds
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jacoline B Ten Brink
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Ralph J Florijn
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, The Netherlands
| | | | - Gislin Dagnelie
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States
| | - Maria M van Genderen
- Bartiméus, Diagnostic Centre for Complex Visual Disorders, Zeist, The Netherlands
| | - Elfride De Baere
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | | | - Julie De Zaeytijd
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Frans P M Cremers
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Alberta A Thiadens
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Caroline C Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Bart P Leroy
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium.,Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium.,Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
| | - Arthur A Bergen
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, The Netherlands.,The Netherlands Institute for Neuroscience (NIN-KNAW), Amsterdam, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, The Netherlands
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5
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van Huet RAC, Siemiatkowska AM, Özgül RK, Yücel D, Hoyng CB, Banin E, Blumenfeld A, Rotenstreich Y, Riemslag FCC, den Hollander AI, Theelen T, Collin RWJ, van den Born LI, Klevering BJ. Retinitis pigmentosa caused by mutations in the ciliary MAK gene is relatively mild and is not associated with apparent extra-ocular features. Acta Ophthalmol 2015; 93:83-94. [PMID: 25385675 DOI: 10.1111/aos.12500] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2014] [Accepted: 06/17/2014] [Indexed: 12/13/2022]
Abstract
PURPOSE Defects in MAK, encoding a protein localized to the photoreceptor connecting cilium, have recently been associated with autosomal recessive retinitis pigmentosa (RP). The aim of this study is to describe our detailed clinical observations in patients with MAK-associated RP, including an assessment of syndromic symptoms frequently observed in ciliopathies. METHODS In this international collaborative study, 11 patients carrying nonsense or missense mutations in MAK were clinically evaluated, including extensive assessment of the medical history, slit-lamp biomicroscopy, ophthalmoscopy, kinetic perimetry, electroretinography (ERG), spectral-domain optical coherence tomography (SD-OCT), autofluorescence imaging and fundus photography. Additionally, we used a questionnaire to evaluate the presence of syndromic features and tested the olfactory function. RESULTS MAK-associated RP is not associated with syndromic features, not even with subclinical dysfunction of the olfactory apparatus. All patients experienced typical RP symptoms of night blindness followed by visual field constriction. Symptoms initiated between childhood and the age of 43 (mean: 23 years). Although some patients experienced vision loss, the visual acuity remained normal in most patients. ERG and ophthalmoscopy revealed classic RP characteristics, and SD-OCT demonstrated thinning of the overall retina, outer nuclear layer and photoreceptor-pigment epithelium complex. CONCLUSION Nonsense and missense mutations in MAK give rise to a non-syndromic recessive RP phenotype without apparent extra-ocular features. When compared to other retinal ciliopathies, MAK-associated RP appears to be relatively mild and shows remarkable resemblance to RP1-associated RP, which could be explained by the close functional relation of these proteins.
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Affiliation(s)
- Ramon A. C. van Huet
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
| | - Anna M. Siemiatkowska
- Department of Human Genetics; Radboud University Medical Center; Nijmegen The Netherlands
| | - Riza K. Özgül
- Institute of Child Health and Metabolism Unit; Department of Pediatrics; Hacettepe University; Ankara Turkey
| | - Didem Yücel
- Institute of Child Health and Metabolism Unit; Department of Pediatrics; Hacettepe University; Ankara Turkey
| | - Carel B. Hoyng
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
| | - Eyal Banin
- Department of Ophthalmology; Hadassah-Hebrew University Medical Center; Jerusalem Israel
| | - Anat Blumenfeld
- Department of Ophthalmology; Hadassah-Hebrew University Medical Center; Jerusalem Israel
| | - Ygal Rotenstreich
- Electrophysiology Clinic; Goldschleger Eye Research Institute; Tel Aviv University; Sheba Medical Centre; Ramat Gan Israel
| | - Frans C. C. Riemslag
- The Rotterdam Eye Hospital; Rotterdam The Netherlands
- Bartiméus, Institute for the Visually Handicapped; Zeist The Netherlands
| | - Anneke I. den Hollander
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
- Department of Human Genetics; Radboud University Medical Center; Nijmegen The Netherlands
- Nijmegen Center for Molecular Life Sciences; Radboud University Medical Center; Nijmegen The Netherlands
| | - Thomas Theelen
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
| | - Rob W. J. Collin
- Department of Human Genetics; Radboud University Medical Center; Nijmegen The Netherlands
- Nijmegen Center for Molecular Life Sciences; Radboud University Medical Center; Nijmegen The Netherlands
| | | | - B. Jeroen Klevering
- Department of Ophthalmology; Radboud University Medical Center; Nijmegen The Netherlands
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Beltran WA, Cideciyan AV, Lewin AS, Hauswirth WW, Jacobson SG, Aguirre GD. Gene augmentation for X-linked retinitis pigmentosa caused by mutations in RPGR. Cold Spring Harb Perspect Med 2014; 5:a017392. [PMID: 25301933 DOI: 10.1101/cshperspect.a017392] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
X-linked retinitis pigmentosa (XLRP) caused by mutations in the RPGR gene is a severe and early onset form of retinal degeneration, and no treatment is currently available. Recent evidence in two clinically relevant canine models shows that adeno-associated viral (AAV)-mediated RPGR gene transfer to rods and cones can prevent disease onset and rescue photoreceptors at early- and mid-stages of degeneration. There is thus a strong incentive for conducting long-term, preclinical efficacy and safety studies, while concomitantly pursuing the detailed phenotypic characterization of XLRP disease in patients that may benefit from such corrective therapy.
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Affiliation(s)
- William A Beltran
- Section of Ophthalmology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Alfred S Lewin
- Department of Molecular Genetics & Microbiology, University of Florida, Gainesville, Florida 32610
| | - William W Hauswirth
- Department of Ophthalmology, University of Florida, Gainesville, Florida 32610
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania 19104
| | - Gustavo D Aguirre
- Section of Ophthalmology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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7
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Evaluation of multimodal imaging in carriers of X-linked retinitis pigmentosa. Exp Eye Res 2013; 113:41-8. [PMID: 23669302 DOI: 10.1016/j.exer.2013.05.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 04/26/2013] [Accepted: 05/01/2013] [Indexed: 11/23/2022]
Abstract
The aim of this study was to investigate visualization of the tapetal-like reflex using current imaging modalities and evaluate SD-OCT changes in known carriers of X-linked retinitis pigmentosa (XLRP); the objective being the development of an optimal protocol for clinicians to identify carriers. Ten XLRP carriers (19 eyes) were examined using color fundus photography, 488 nm reflectance (488-R), near-infrared reflectance (NIR-R), autofluorescence (AF) and spectral domain optical coherence tomography (SD-OCT) imaging (Spectralis SLO-OCT, Heidelberg). Horizontal line scans through the fovea were acquired in all subjects and in a group of 10 age-similar controls. Peripheral SD-OCT scans (extending to 27.5° eccentricity) were also acquired in both eyes of 7 carriers. MP-1 microperimetery (10-2 pattern; Nidek) was performed in one eye of each carrier. For the XLRP carriers, a tapetal reflex was observed with all imaging modalities in 8 of 19 eyes. It had the same retinal location on color fundus, 488-R and NIR-R imaging but a different location on AF. The tapetal reflex was most easily detected in 488-R images. The horizontal foveal SD-OCT scans were qualitatively normal, but measurements showed significant outer retinal layer thinning in all eyes. Additionally, the 14 eyes with peripheral SD-OCTs demonstrated patchy loss of the inner segment ellipsoid band. Microperimetry exhibited patchy visual sensitivity loss in 9 eyes. Full field ERGs were variable, ranging from normal to severely abnormal rod and cone responses. Our findings suggest that an optimal protocol for identifying carriers of XLRP should include 488-R imaging in a multimodal approach. Peripheral SD-OCT imaging and central retinal layer quantification revealed significant structural abnormalities.
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8
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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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9
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Sharon D, Sandberg MA, Rabe VW, Stillberger M, Dryja TP, Berson EL. RP2 and RPGR mutations and clinical correlations in patients with X-linked retinitis pigmentosa. Am J Hum Genet 2003; 73:1131-46. [PMID: 14564670 PMCID: PMC1180492 DOI: 10.1086/379379] [Citation(s) in RCA: 157] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2003] [Accepted: 08/29/2003] [Indexed: 11/03/2022] Open
Abstract
We determined the mutation spectrum of the RP2 and RPGR genes in patients with X-linked retinitis pigmentosa (XLRP) and searched for correlations between categories of mutation and severity of disease. We screened 187 unrelated male patients for mutations, including 135 with a prior clinical diagnosis of XLRP, 11 with probable XLRP, 30 isolate cases suspected of having XLRP, and 11 with cone-rod degeneration. Mutation screening was performed by single-strand conformation analysis and by sequencing of all RP2 exons and RPGR exons 1-14, ORF15, and 15a. The refractive error, visual acuity, final dark-adapted threshold, visual field area, and 30-Hz cone electroretinogram (ERG) amplitude were measured in each patient. Among the 187 patients, we found 10 mutations in RP2, 2 of which are novel, and 80 mutations in RPGR, 41 of which are novel; 66% of the RPGR mutations were within ORF15. Among the 135 with a prior clinical diagnosis of XLRP, mutations in the RP2 and RPGR genes were found in 9 of 135 (6.7%) and 98 of 135 (72.6%), respectively, for a total of 79% of patients. Patients with RP2 mutations had, on average, lower visual acuity but similar visual field area, final dark-adapted threshold, and 30-Hz ERG amplitude compared with those with RPGR mutations. Among patients with RPGR mutations, those with ORF15 mutations had, on average, a significantly larger visual field area and a borderline larger ERG amplitude than did patients with RPGR mutations in exons 1-14. Among patients with ORF15 mutations, regression analyses showed that the final dark-adapted threshold became lower (i.e., closer to normal) and that the 30-Hz ERG amplitude increased as the length of the wild-type ORF15 amino acid sequence increased. Furthermore, as the length of the abnormal amino acid sequence following ORF15 frameshift mutations increased, the severity of disease increased.
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Affiliation(s)
- Dror Sharon
- Ocular Molecular Genetics Institute and the Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston
| | - Michael A. Sandberg
- Ocular Molecular Genetics Institute and the Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston
| | - Vivian W. Rabe
- Ocular Molecular Genetics Institute and the Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston
| | - Melissa Stillberger
- Ocular Molecular Genetics Institute and the Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston
| | - Thaddeus P. Dryja
- Ocular Molecular Genetics Institute and the Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston
| | - Eliot L. Berson
- Ocular Molecular Genetics Institute and the Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston
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10
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Koenekoop RK, Loyer M, Hand CK, Al Mahdi H, Dembinska O, Beneish R, Racine J, Rouleau GA. Novel RPGR mutations with distinct retinitis pigmentosa phenotypes in French-Canadian families. Am J Ophthalmol 2003; 136:678-87. [PMID: 14516808 DOI: 10.1016/s0002-9394(03)00331-3] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE To characterize the molecular defects in two x-linked retinitis pigmentosa (RP) families. We hypothesized that different RPGR mutations result in distinct RP phenotypes. DESIGN Observational case series. METHODS Fifteen members in family I and three members in family II were evaluated. Full ophthalmic evaluations were done. Linkage analyses were performed and likelihood of odds scores (LOD score) were calculated. For mutation analyses, we used dHPLC and automated sequencing. RESULTS Two novel RPGR mutations were identified in the two families; a Glu 414 (2-bp del) frameshift mutation in family I and an IVS 2-1 (g to a) splice site mutation in family II. All male family members in family I were severely affected by RP but maintained central visual acuities until their 50s and did not develop a bull's eye maculopathy. The female phenotype was highly variable. Some of the carriers exhibited a severe phenotype, one female displayed an asymmetric phenotype, and other carriers were asymptomatic. All members with the RPGR frameshift mutation exhibited rod-cone electroretinograms abnormalities, whereas five members had hearing loss. Male members of family II were severely affected, with early visual acuity loss, central scotomas, and bull's eye maculopathy. The female family members were asymptomatic but displayed cone-rod electroretinograms changes. There was no hearing loss. CONCLUSIONS Different RPGR mutations lead to distinct RP phenotypes, with a highly variable inter- and intrafamilial phenotypic spectrum of disease that is associated with the type of mutation in RPGR and nonrandom X chromosome inactivation, respectively.
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11
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Lorenz B, Andrassi M, Kretschmann U. Phenotype in two families with RP3 associated with RPGR mutations. Ophthalmic Genet 2003; 24:89-101. [PMID: 12789573 DOI: 10.1076/opge.24.2.89.14001] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
OBJECTIVE To describe the phenotype of three patients and two carriers from two families with mutations in the RPGR gene. The genotypes (a 75-kb deletion on the X chromosome spanning the RPGR gene and the first exon of the SRPX gene, and a stop mutation (G52X) in the RPGR gene) have been reported previously. METHODS A clinical examination including Goldmann perimetry, full-field electroretinography (ERG), dark adaptometry, and dark- and light-adapted two-color threshold (500-nm cut-off, 600-nm cut-on filter) perimetry was performed in all patients and one carrier. The second carrier was only examined clinically. RESULTS All affected males presented with a marked decrease in visual acuity of 0.3 to 0.5 at the age of 17-22.5 years, and a typical fundus appearance. The stop mutation (G52X) appeared to be associated with a more pronounced bone spicule formation compared to the deletion of the entire RPR gene and the first exon of the SRPX gene. The kinetic visual fields were constricted to < 20 degrees eccentricity, in part with a residual island in the temporal field. Using two-color dark-adapted threshold perimetry, rod function was more reduced than cone function. The ERG was extinguished. The carrier with the stop mutation showed sectorial peripheral bone spicules and ERG changes typical of carriers of XLRP. The carrier with the deletion had no visual complaints, full visual acuity, and only minimal peripheral retinal changes. Goldmann perimetry showed minor peripheral defects with small targets. ERG amplitudes were reduced below the 10th percentile of normals, without selective loss in rods or cones. The scotopic (rod) sensitivity loss at 500 nm was more pronounced than the photopic (cone) sensitivity loss at 600 nm. Neither of the two carriers showed a tapetal reflex. CONCLUSION The affected males of the two families with RPGR mutations already exhibited retinitis pigmentosa with severe impairment of the rod and cone system during their second decade of life. The degree of bone spicules differed between the two families. Psychophysics detected a slightly more pronounced affection of the rod system compared to the cone system in both the hemizygous males and the carrier with the deletion of the RPGR gene and the first exon of the SRPX gene. Psychophysics disclosed mild progression of the disease in the carrier underlining the potential of the method in monitoring the disease course. As in most other reported phenotypes of RPGR mutations, no tapetal reflex was found in the carriers.
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Affiliation(s)
- Birgit Lorenz
- Department of Pediatric Ophthalmology, Strabismology, and Ophthalmic Genetics, Klinikum, University of Regensburg, Franz-Josef-Strauss-Allee 11, D-93053 Regensburg, Germany.
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12
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Abstract
Mutations in RPGR, retinitis pigmentosa GTPase regulator, are associated with RP3 type of X-linked retinitis pigmentosa, a severe, non-syndromic form of retinal degeneration. In the majority of subjects RPGR mutations are associated with a typical rod-cone degeneration, but in a small number, cone-rod dystrophy, deafness, and abnormalities in respiratory cilia have been noted. Alternative splicing of RPGR is complex in all species examined. In RP3 patients, mutations have been found in exons 1-14 and ORF15, thus delineating a transcript necessary for normal retinal function in humans. The great majority of mutations are predicted to result in premature termination of translation. These mutations are scattered over exons 1-14 and ORF15, while most missense mutations occur in a domain with homology to the protein RCC1, encoded by exons 1-10. Exon ORF15 is a "hot spot" for mutation, at least in the British population, in which it harbors 80% of the mutations found within a sample of 47 X-linked retinitis pigmentosa patients. Most RPGR mutations are unique to single families, which makes it difficult to demonstrate phenotype-genotype correlations.
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Affiliation(s)
- Raf Vervoort
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, UK
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13
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Arden GB. The absence of diabetic retinopathy in patients with retinitis pigmentosa: implications for pathophysiology and possible treatment. Br J Ophthalmol 2001; 85:366-70. [PMID: 11222350 PMCID: PMC1723904 DOI: 10.1136/bjo.85.3.366] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- G B Arden
- Applied Vision Research Centre, City University, Northampton Square London EC1V 0HB, UK.
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14
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Hong DH, Pawlyk BS, Shang J, Sandberg MA, Berson EL, Li T. A retinitis pigmentosa GTPase regulator (RPGR)- deficient mouse model for X-linked retinitis pigmentosa (RP3). Proc Natl Acad Sci U S A 2000; 97:3649-54. [PMID: 10725384 PMCID: PMC16294 DOI: 10.1073/pnas.97.7.3649] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The X-linked RP3 locus codes for retinitis pigmentosa GTPase regulator (RPGR), a protein of unknown function with sequence homology to the guanine nucleotide exchange factor for Ran GTPase. We created an RPGR-deficient murine model by gene knockout. In the mutant mice, cone photoreceptors exhibit ectopic localization of cone opsins in the cell body and synapses and rod photoreceptors have a reduced level of rhodopsin. Subsequently, both cone and rod photoreceptors degenerate. RPGR was found normally localized to the connecting cilia of rod and cone photoreceptors. These data point to a role for RPGR in maintaining the polarized protein distribution across the connecting cilium by facilitating directional transport or restricting redistribution. The function of RPGR is essential for the long-term maintenance of photoreceptor viability.
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Affiliation(s)
- D H Hong
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA 02114, USA
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15
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A retinitis pigmentosa GTPase regulator (RPGR)-deficient mouse model for X-linked retinitis pigmentosa (RP3). Proc Natl Acad Sci U S A 2000; 97. [PMID: 10725384 PMCID: PMC16294 DOI: 10.1073/pnas.060037497] [Citation(s) in RCA: 119] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The X-linked RP3 locus codes for retinitis pigmentosa GTPase regulator (RPGR), a protein of unknown function with sequence homology to the guanine nucleotide exchange factor for Ran GTPase. We created an RPGR-deficient murine model by gene knockout. In the mutant mice, cone photoreceptors exhibit ectopic localization of cone opsins in the cell body and synapses and rod photoreceptors have a reduced level of rhodopsin. Subsequently, both cone and rod photoreceptors degenerate. RPGR was found normally localized to the connecting cilia of rod and cone photoreceptors. These data point to a role for RPGR in maintaining the polarized protein distribution across the connecting cilium by facilitating directional transport or restricting redistribution. The function of RPGR is essential for the long-term maintenance of photoreceptor viability.
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16
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Uhlmann J, Wiemann S, Ponstingl H. DelGEF, an RCC1-related protein encoded by a gene on chromosome 11p14 critical for two forms of hereditary deafness. FEBS Lett 1999; 460:153-60. [PMID: 10571079 DOI: 10.1016/s0014-5793(99)01333-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
We have cloned a human cDNA, DELGEF (deafness locus associated putative guanine nucleotide exchange factor), derived from a 225 kb genomic sequence of chromosome 11p14, critical for the Usher 1C syndrome and for DFNB18, a locus for non-syndromic sensorineural deafness. The amino acid sequence of the protein hDelGEF1 is homologous to the nucleotide exchange factor RCCI for the small GTPase Ran. hDelGEF2 is derived from the same DELGEF gene by alternative splicing. In addition, we have identified a murine homologue, mDelGEF. The ubiquitously expressed soluble protein hDelGEF1 is found both in the cyytoplasm and in the nucleus. Overexpressed hDelGEF2 colocalizes with mitochondria.
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Affiliation(s)
- J Uhlmann
- Division for Molecular Biology of Mitosis, German Cancer Research Center, Heidelberg
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17
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Rosenberg T, Schwahn U, Feil S, Berger W. Genotype-phenotype correlation in X-linked retinitis pigmentosa 2 (RP2). Ophthalmic Genet 1999; 20:161-72. [PMID: 10520237 DOI: 10.1076/opge.20.3.161.2278] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE To identify possible correlations between the putative mutations and the clinical characteristics in X-linked retinitis pigmentosa, RP2. DESIGN A retrospective, descriptive clinical study. MATERIAL The ophthalmological files on affected persons from three Danish families with identified pathogenic mutations in the RP2 gene. RESULTS Mutation analysis in 14 Danish families with X-linked retinitis pigmentosa revealed disease-associated sequence alterations in eight of them. Five mutations were detected in the RP3 gene (RPGR) and three in the RP2 gene. Genotype-phenotype comparison in the three RP2 families revealed striking interfamilial phenotypic differences. Severe phenotypes were associated with a null mutation Gln26stop and a missense mutation Arg118His. These families differed mutually with respect to retinal appearance. Affected carriers had a delayed onset by three decades. Tapetal reflexes were not observed in the carriers. An in-frame deletion DeltaSer6 was associated with a milder phenotype. CONCLUSIONS Interfamilial differences in RP2 phenotype might be related to the type and location of the mutational event. Due to a considerable overlap between RP2 and RP3 phenotypes, the genotype cannot safely be deduced from conventional clinical examination methods.
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Affiliation(s)
- T Rosenberg
- National Eye Clinic for the Visually Impaired, Hellerup, Denmark.
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Kirschner R, Rosenberg T, Schultz-Heienbrok R, Lenzner S, Feil S, Roepman R, Cremers FP, Ropers HH, Berger W. RPGR transcription studies in mouse and human tissues reveal a retina-specific isoform that is disrupted in a patient with X-linked retinitis pigmentosa. Hum Mol Genet 1999; 8:1571-8. [PMID: 10401007 DOI: 10.1093/hmg/8.8.1571] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is a genetically heterogeneous group of progressive retinal degenerations. The disease process is initiated by premature apoptosis of rod photoreceptor cells in the retina, which leads to reduced visual acuity and, eventually, complete blindness. Mutations in the retinitis pigmentosa GTPase regulator ( RPGR ), a ubiquitously expressed gene at the RP3 locus in Xp21.1, account for approximately 20% of all X-linked cases. We have analysed the expression of this gene by northern blot hybridization, cDNA library screening and RT-PCR in various organs from mouse and man. These studies revealed at least 12 alternatively spliced isoforms. Some of the transcripts are tissue specific and contain novel exons, which elongate or truncate the previously reported open reading frame of the mouse and human RPGR gene. One of the newly identified exons is expressed exclusively in the human retina and mouse eye and contains a premature stop codon. The deduced polypeptide lacks 169 amino acids from the C-terminus of the ubiquitously expressed variant, including an isoprenylation site. Moreover, this exon was found to be deleted in a family with XLRP. Our results indicate tissue-dependent regulation of alternative splicing of RPGR in mouse and man. The discovery of a retina-specific transcript may explain why phenotypic abberations in RP3 are confined to the eye.
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Affiliation(s)
- R Kirschner
- Max-Planck-Institut für molekulare Genetik, Ihnestrasse 73, D-14195 Berlin, Germany.
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