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Gocuk SA, Edwards TL, Jolly JK, Ayton LN. Perspectives of carriers of X-linked retinal diseases on genetic testing and gene therapy: A global survey. Clin Genet 2024; 105:150-158. [PMID: 37859457 DOI: 10.1111/cge.14442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/03/2023] [Accepted: 10/06/2023] [Indexed: 10/21/2023]
Abstract
Female carriers of X-linked inherited retinal diseases (IRDs) are burdened with potentially passing their disease-causing variant to future generations, as well as exhibiting signs of retinal disease themselves. This study aimed to investigate carriers' experiences of genetic testing, emotions relating to having affected children, and their knowledge regarding genetic testing and gene therapy. An online survey was advertised to self-identified carriers worldwide. Two hundred and twenty-eight carriers completed the survey with mean age of 51 years (SD ± 15.0). A majority of respondents resided in the United States of America (51%), Australia (19%), and the United Kingdom (14%). Most carriers identified with feelings of guilt (70%), concern (91%), and anxiety (88%) for their child. Female carriers who had given birth to children had significantly greater gene therapy knowledge compared to carriers who had not (p < 0.05). Respondents agreed that their eyecare provider and general practitioner helped them understand their condition (63%), however, few carriers reported receiving psychological counselling (9%) or family planning advice (5%). Most respondents (78%) agreed that gene therapy should be available to carriers. This study emphasises the importance of providing appropriate counselling to female carriers and illustrates the motivation of many to participate in emerging treatment options, such as gene therapy.
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Affiliation(s)
- Sena A Gocuk
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Thomas L Edwards
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
| | - Jasleen K Jolly
- Vision and Eye Research Institute, Anglia Ruskin University, Cambridge, UK
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, University of Melbourne, Melbourne, Victoria, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, Melbourne, Victoria, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia
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Wang YZ, Juroch K, Chen Y, Ying GS, Birch DG. Deep Learning-Facilitated Study of the Rate of Change in Photoreceptor Outer Segment Metrics in RPGR-Related X-Linked Retinitis Pigmentosa. Invest Ophthalmol Vis Sci 2023; 64:31. [PMID: 37988107 PMCID: PMC10668621 DOI: 10.1167/iovs.64.14.31] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Accepted: 11/02/2023] [Indexed: 11/22/2023] Open
Abstract
Purpose The aim of this retrospective cohort study was to obtain three-dimensional (3D) photoreceptor outer segment (OS) metrics measurements with the assistance of a deep learning model (DLM) and to evaluate the longitudinal change in OS metrics and associated factors in retinitis pigmentosa GTPase regulator (RPGR) X-linked retinitis pigmentosa (XLRP). Methods The study included 34 male patients with RPGR-associated XLRP who had preserved ellipsoid zone (EZ) within their spectral-domain optical coherence tomography volume scans and an approximate 2-year or longer follow-up. Volume scans were segmented using a DLM with manual correction for EZ and apical retinal pigment epithelium (RPE). OS metrics were measured from 3D EZ-RPE layers of volume scans. Linear mixed-effects models were used to calculate the rate of change in OS metrics and the associated factors, including baseline age, baseline OS metrics, and follow-up duration. Results The mean (standard deviation) of progression rates were -0.28 (0.43) µm/y, -0.73 (0.61) mm2/y, and -0.014 (0.012) mm3/y for OS thickness, EZ area, and OS volume, respectively. In multivariable analysis, the progression rates of EZ area and OS volume were strongly associated with their baseline values, with faster decline in eyes with larger baseline values (P ≤ 0.003), and nonlinearly associated with the baseline age (P ≤ 0.003). OS thickness decline was not associated with its baseline value (P = 0.32). Conclusions These results provide evidence to support using OS metrics as biomarkers to assess the progression of XLRP and as the outcome measures of clinical trials. Given that their progression rates are dependent on their baseline values, the baseline EZ area and OS volume should be considered in the design and statistical analysis of future clinical trials. Deep learning may provide a useful tool to reduce the burden of human graders to analyze OCT scan images and to facilitate the assessment of disease progression and treatment trials for retinitis pigmentosa.
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Affiliation(s)
- Yi-Zhong Wang
- Retina Foundation of the Southwest, Dallas, Texas, United States
- Department of Ophthalmology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States
| | - Katherine Juroch
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Yineng Chen
- Center for Preventive Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Gui-Shuang Ying
- Center for Preventive Ophthalmology and Biostatistics, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - David G. Birch
- Retina Foundation of the Southwest, Dallas, Texas, United States
- Department of Ophthalmology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas, United States
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Nowomiejska K, Baltaziak K, Całka P, Ciesielka M, Teresiński G, Rejdak R. Identification of the RPGR Gene Pathogenic Variants in a Cohort of Polish Male Patients with Retinitis Pigmentosa Phenotype. Genes (Basel) 2023; 14:1950. [PMID: 37895299 PMCID: PMC10606843 DOI: 10.3390/genes14101950] [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: 09/17/2023] [Revised: 10/13/2023] [Accepted: 10/15/2023] [Indexed: 10/29/2023] Open
Abstract
The goal of the study was to explore the spectrum of pathogenic variants in the RPGR gene in a group of male Polish patients with a retinitis pigmentosa (RP) phenotype. A total of 45 male index patients, including twins, being members of 44 families, were screened for pathogenic variants in the RPGR gene via the direct sequencing of PCR-amplified genomic DNA and underwent a comprehensive ophthalmological examination in one center located in Poland. A total of two pathogenic and five likely pathogenic variants in eight patients (18%) were detected in the studied cohort. Of these, five variants were novel, and five disease-causing variants (71%) were identified within the ORF15 mutational hotspot of the RPGR gene. The median age of onset of the disease was 10 years (range 6-14 years), the median age during the examination was 30 years (range 20-47 years), and the median visual acuity was 0.4 (range 0.01-0.7). The majority of patients had middle constriction of the visual field and thinning of the central foveal thickness. Dizygotic twins bearing the same hemizygous mutation showed a different retinal phenotype in regard to the severity of the symptoms. This is the first RPGR mutation screening in Poland showing a prevalence of 18% of RPGR pathogenic mutations and likely pathogenic variants in the studied cohort of male patients with an RP phenotype.
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Affiliation(s)
- Katarzyna Nowomiejska
- Chair and Department of General and Pediatric Ophthalmology, Medical University of Lublin, 20-059 Lublin, Poland; (K.B.); (R.R.)
| | - Katarzyna Baltaziak
- Chair and Department of General and Pediatric Ophthalmology, Medical University of Lublin, 20-059 Lublin, Poland; (K.B.); (R.R.)
| | - Paulina Całka
- Department of Forensic Medicine, Medical University of Lublin, 20-059 Lublin, Poland; (P.C.); (M.C.); (G.T.)
| | - Marzanna Ciesielka
- Department of Forensic Medicine, Medical University of Lublin, 20-059 Lublin, Poland; (P.C.); (M.C.); (G.T.)
| | - Grzegorz Teresiński
- Department of Forensic Medicine, Medical University of Lublin, 20-059 Lublin, Poland; (P.C.); (M.C.); (G.T.)
| | - Robert Rejdak
- Chair and Department of General and Pediatric Ophthalmology, Medical University of Lublin, 20-059 Lublin, Poland; (K.B.); (R.R.)
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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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Liu HL, Gao FG, Wang DD, Hu FY, Xu P, Chang Q, Xu GZ, Wu JH. Mutation Analysis of the RPGR Gene in a Chinese Cohort. Front Genet 2022; 13:850122. [PMID: 35432464 PMCID: PMC9008860 DOI: 10.3389/fgene.2022.850122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Accepted: 02/17/2022] [Indexed: 12/05/2022] Open
Abstract
Purpose: The purpose of this study was to investigate the clinical and genetic characteristics of the retinitis pigmentosa GTPase regulatory factor gene (RPGR) in a Chinese cohort. Methods: A retrospective analysis was performed on 80 subjects with RPGR-retinal dystrophy (RPGR-RD) for detailed genetic and clinical characterization. The panel-based next-generation sequencing of 792 causative genes involved in common genetic eye diseases was conducted in all individuals, followed by clinical variant interpretation. Information, including age, sex, geographic distribution, family history, consanguineous marriage, age at symptom onset, disease duration, best corrected visual acuity (BCVA), and complete ophthalmologic examination results, was collected. Results: This cohort (41 men and 39 women) included 26 families (26 probands and their available family members) and 13 sporadic cases. The average age of these participants was 36.35 ± 17.68 years, and the majority of the families were from eastern China (28 families, 71.79%). The average duration of disease in the probands was 22.68 ± 15.80 years. In addition, the average BCVA values of the right and left eyes in the probands were 0.96 ± 0.77 and 1.00 ± 0.77, respectively. A total of 34 RPGR variants were identified, including 6 reported variants and 28 novel variants. Among these variants, NM_001034853.1: c.2899_2902delGAAG and c.2744_2745ins24 were considered de novo variants. The majority of the RPGR variants were classified as likely pathogenic, accounting for 70.59% of the variants (24 variants). The most common nucleotide and amino acid changes identified in this study were deletions (16 variants, 45.06%) and frameshifts (17 variants, 50.00%), respectively. Genetic analysis revealed that these RPGR variants were distributed in 10 different subregions of RPGR, and 70.59% of the RPGR variants (24 variants) were located in exon 15. Four RPGR variants, NM_001034853.1: c.2405_2406delAG, c.1345C > T, c.2218G > T and c.2236_2237delGA, occurred at a very high frequency of 28.21% (11 families) among 39 unrelated families. Conclusion: This study expands the known mutational spectrum of RPGR, and we provide a new reference for the genetic diagnosis of RPGR variants.
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Affiliation(s)
- Hong-Li Liu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Feng-Guan Gao
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Dan-Dan Wang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Fang-Yuan Hu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Ping Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Qing Chang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Ge-Zhi Xu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
| | - Ji-Hong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai Medical College, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- Key Laboratory of Myopia (Fudan University), Chinese Academy of Medical Sciences, National Health Commission, Shanghai, China
- *Correspondence: Ji-Hong Wu,
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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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Analysis of imaging biomarkers and retinal nerve fiber layer thickness in RPGR-associated retinitis pigmentosa. Graefes Arch Clin Exp Ophthalmol 2021; 259:3597-3604. [PMID: 34287692 PMCID: PMC8589744 DOI: 10.1007/s00417-021-05233-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 03/22/2021] [Accepted: 05/03/2021] [Indexed: 01/23/2023] Open
Abstract
Purpose To investigate multimodal retinal imaging characteristics including the retinal nerve fiber layer (RNFL) thickness in patients with RPGR-associated retinitis pigmentosa (RP). Methods This cross-sectional case–control study included 17 consecutive patients (median age, 21 years) with RPGR-associated RP who underwent retinal imaging including optical coherence tomography (OCT), short-wavelength fundus autofluorescence (AF) imaging, and RNFL scans centered on the optic disc. RNFL thickness was manually segmented and compared to clinical and imaging parameters including the transfoveal ellipsoid zone (EZ) width, the horizontal diameter of the macular hyperautofluorescent ring. RNFL thickness was compared to 17 age- and sex-matched controls. Results In patients with RPGR-associated RP, the EZ width (R2 = 0.65), the central hyperautofluorescent ring on AF images (R2 = 0.72), and visual acuity (R2 = 0.68) were negatively correlated with age. In comparison to controls, a significantly (p < 0.0001) increased global RNFL thickness was identified in RPGR-associated RP, which was, however, less pronounced in progressed disease as indicated by the EZ width or the diameter of the central hyperautofluorescent ring. Conclusions This study describes retinal characteristics in patients with RPGR-associated RP including a pronounced peripapillary RNFL thickness compared to healthy controls. These results contribute to the knowledge about imaging biomarkers in RP, which might be of interest for therapeutic approaches such as gene replacement therapies.
![]() Supplementary Information The online version contains supplementary material available at 10.1007/s00417-021-05233-w.
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Chivers M, Li N, Pan F, Wieffer H, Slowik R, Leartsakulpanitch J. The Burden of X-Linked Retinitis Pigmentosa on Patients and Society: A Narrative Literature Review. CLINICOECONOMICS AND OUTCOMES RESEARCH 2021; 13:565-572. [PMID: 34188501 PMCID: PMC8236258 DOI: 10.2147/ceor.s297287] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/10/2021] [Indexed: 01/18/2023] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is a severe form of retinitis pigmentosa (RP), a rare, inherited retinal degenerative disorder, that causes blindness. The aim of this literature review was to identify what is currently known about the burden of XLRP. Literature databases were searched for articles describing the clinical, humanistic, or economic burden of XLRP or RP in the US, Japan, France, Germany, Italy, Spain, and the UK, published in English between 2014 and 2019; gray literature and cited references were reviewed. Literature describing XLRP is limited as this is an ultra-rare condition; findings relating to burden of RP have been reported with interpretation of how burden differs for XLRP. In XLRP, night blindness usually presents in the first decade of life, followed by loss of peripheral and then central vision; legal blindness is reported at a median of 45 years in affected males (vs median 70 years for RP). There is limited evidence of humanistic or economic burden specific to XLRP; one study identified greater vision-related activity limitations in patients with XLRP compared with the wider RP population. Qualitative studies describe increased humanistic burden for people living with RP; difficulty undertaking everyday tasks (driving, hobbies, reading), psychosocial burden and barriers to work and career. People described the emotional impact of dealing with progression of RP, ongoing social and physical challenges, and the impact of RP on relationships. The economic burden of RP is associated with lost productivity, greater healthcare costs and increasing requirement for formal and informal care. In summary, XLRP remains an untreatable condition that can impact people from childhood. The humanistic burden of RP has been shown to increase as the disease progresses; hence, in XLRP the earlier onset and earlier progression to blindness during prime working years may mean a comparatively greater lifetime burden of disease.
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Affiliation(s)
| | - Nan Li
- Janssen Global Services,LLC, Raritan, NJ, 08869, USA
| | - Feng Pan
- Janssen Global Services,LLC, Raritan, NJ, 08869, USA
| | | | - Rafal Slowik
- Janssen Global Services,LLC, Raritan, NJ, 08869, USA
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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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Affiliation(s)
- Ajit Thakur
- Sagarmatha Choudhary Eye Hospital, Lahan, Nepal
E‐mail:
| | - Lila Puri
- Sagarmatha Choudhary Eye Hospital, Lahan, Nepal
E‐mail:
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De Silva SR, Arno G, Robson AG, Fakin A, Pontikos N, Mohamed MD, Bird AC, Moore AT, Michaelides M, Webster AR, Mahroo OA. The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies. Prog Retin Eye Res 2020; 82:100898. [PMID: 32860923 DOI: 10.1016/j.preteyeres.2020.100898] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/07/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research.
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Affiliation(s)
- Samantha R De Silva
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Ana Fakin
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Moin D Mohamed
- Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Alan C Bird
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK; Section of Ophthalmology, King's College London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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12
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Morizur L, Herardot E, Monville C, Ben M'Barek K. Human pluripotent stem cells: A toolbox to understand and treat retinal degeneration. Mol Cell Neurosci 2020; 107:103523. [PMID: 32634576 DOI: 10.1016/j.mcn.2020.103523] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/24/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP) are retinal degenerative disorders that dramatically damage the retina. As there is no therapeutic option for the majority of patients, vision is progressively and irremediably lost. Owing to their unlimited renewal and potency to give rise to any cell type of the human adult body, human pluripotent stem cells (hPSCs) have been extensively studied in recent years to develop more physiologically relevant in vitro cellular models. Such models open new perspectives to investigate the pathological molecular mechanisms of AMD and RP but also in drug screening. Moreover, proof-of-concept of hPSC-derived retinal cell therapy in animal models have led to first clinical trials. This review outlines the recent advances in the use of hPSCs in pathological modeling of retinal degeneration and their use in regenerative medicine. We also address the associated limitations and challenges that need to be overcome when using hPSCs.
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Affiliation(s)
- Lise Morizur
- INSERM U861, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, 91100 Corbeil-Essonnes, France; Université Paris-Saclay, Université d'Evry, U861, 91100 Corbeil-Essonnes, France; Centre d'Etude des Cellules Souches, 91100 Corbeil-Essonnes, France
| | - Elise Herardot
- INSERM U861, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, 91100 Corbeil-Essonnes, France; Université Paris-Saclay, Université d'Evry, U861, 91100 Corbeil-Essonnes, France
| | - Christelle Monville
- INSERM U861, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, 91100 Corbeil-Essonnes, France; Université Paris-Saclay, Université d'Evry, U861, 91100 Corbeil-Essonnes, France.
| | - Karim Ben M'Barek
- INSERM U861, I-Stem, AFM, Institute for Stem Cell Therapy and Exploration of Monogenic Diseases, 91100 Corbeil-Essonnes, France; Université Paris-Saclay, Université d'Evry, U861, 91100 Corbeil-Essonnes, France; Centre d'Etude des Cellules Souches, 91100 Corbeil-Essonnes, France.
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13
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Garafalo AV, Cideciyan AV, Héon E, Sheplock R, Pearson A, WeiYang Yu C, Sumaroka A, Aguirre GD, Jacobson SG. Progress in treating inherited retinal diseases: Early subretinal gene therapy clinical trials and candidates for future initiatives. Prog Retin Eye Res 2020; 77:100827. [PMID: 31899291 PMCID: PMC8714059 DOI: 10.1016/j.preteyeres.2019.100827] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/21/2019] [Accepted: 12/26/2019] [Indexed: 12/15/2022]
Abstract
Due to improved phenotyping and genetic characterization, the field of 'incurable' and 'blinding' inherited retinal diseases (IRDs) has moved substantially forward. Decades of ascertainment of IRD patient data from Philadelphia and Toronto centers illustrate the progress from Mendelian genetic types to molecular diagnoses. Molecular genetics have been used not only to clarify diagnoses and to direct counseling but also to enable the first clinical trials of gene-based treatment in these diseases. An overview of the recent reports of gene augmentation clinical trials by subretinal injections is used to reflect on the reasons why there has been limited success in this early venture into therapy. These first-in human experiences have taught that there is a need for advancing the techniques of delivery of the gene products - not only for refining further subretinal trials, but also for evaluating intravitreal delivery. Candidate IRDs for intravitreal gene delivery are then suggested to illustrate some of the disorders that may be amenable to improvement of remaining central vision with the least photoreceptor trauma. A more detailed understanding of the human IRDs to be considered for therapy and the calculated potential for efficacy should be among the routine prerequisites for initiating a clinical trial.
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Affiliation(s)
- Alexandra V Garafalo
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Rebecca Sheplock
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Alexander Pearson
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Caberry WeiYang Yu
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Alexander Sumaroka
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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14
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Song C, Dufour VL, Cideciyan AV, Ye GJ, Swider M, Newmark JA, Timmers AM, Robinson PM, Knop DR, Chulay JD, Jacobson SG, Aguirre GD, Beltran WA, Shearman MS. Dose Range Finding Studies with Two RPGR Transgenes in a Canine Model of X-Linked Retinitis Pigmentosa Treated with Subretinal Gene Therapy. Hum Gene Ther 2020; 31:743-755. [PMID: 32414297 DOI: 10.1089/hum.2019.337] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recombinant adeno-associated viral (rAAV) vector-mediated gene therapy is being developed to treat X-linked retinitis pigmentosa (XLRP) in patients with mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene. In preparation for a clinical gene therapy trial, we conducted dose range finding (DRF) studies with an AAV2 capsid with three surface tyrosine residues changed to phenylalanine (AAV2tYF) vector administered by subretinal injection in a naturally occurring RPGR-mutant canine model (XLPRA2) to compare two different human RPGR (hRPGR) transgenes and to establish a reasonable starting dose for a clinical trial. Different dose levels of two candidate vectors (0.15 mL at 1.2 × 1010-3.0 × 1012 vg/mL of rAAV2tYF-GRK1-hRPGRco or 4 × 1010-3.0 × 1012 vg/mL of rAAV2tYF-GRK1-hRPGRstb), 6.0 × 1011 vg/mL rAAV5-GRK1-hRPGRco reference vector or Vehicle were subretinally administered, and the dogs were followed for 8 weeks postdose. Ophthalmic examinations, analyses of retinal structure by in vivo imaging using confocal scanning laser ophthalmoscopy (cSLO)/optical coherence tomography (OCT) in the Lower (4.0 × 1010 vg/mL) and Lowest (1.2 × 1010 vg/mL) Doses, immunological responses by cell based assays or enzyme-linked immunosorbent assay, RPGR transgene expression, and reversal of opsin mislocalization by immunohistochemistry were performed. No sustained signs of ocular discomfort or ophthalmic complications were noted in any of the injected eyes except some in the High Dose group (3.0 × 1012 vg/mL), which showed signs of retinal detachment and inflammation. A change in fundus reflectivity suggestive of a rescue effect was seen in the High, Mid (6.0 × 1011 vg/mL), and Low (1.2 × 1011 vg/mL) Dose groups. cSLO/OCT demonstrated qualitative and quantitative evidence of rescue effect in eyes treated with the Lower Dose. Anti-hRPGR antibodies were absent, but neutralizing antibody titers against AAV2 were detected in all animals dosed with rAAV2tYF in an apparent dose-related pattern. RPGR expression was stronger for rAAV2tYF-GRK1-hRPGRco compared to rAAV2tYF-GRK1-hRPGRstb at all dose levels. Subretinal administration of rAAV2tYF-GRK1-hRPGRco and rAAV2tYF-GRK1-hRPGRstb both corrected rod and cone opsin mislocalization, two early markers of disease in the XLPRA2 canine model of RPGR-XLRP. These results support the selection and use of rAAV2tYF-GRK1-hRPGRco (AGTC-501) and guided the initial doses in clinical studies in patients with XLRP caused by RPGR mutations.
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Affiliation(s)
- Chunjuan Song
- Applied Genetic Technologies Corporation, Alachua, Florida, USA
| | - Valérie L Dufour
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Guo-Jie Ye
- Applied Genetic Technologies Corporation, Alachua, Florida, USA
| | - Malgorzata Swider
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | | | | | | | - David R Knop
- Applied Genetic Technologies Corporation, Alachua, Florida, USA
| | | | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - William A Beltran
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Mark S Shearman
- Applied Genetic Technologies Corporation, Alachua, Florida, USA
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15
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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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16
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Select pediatric vitreoretinal disease in the setting of Turner's syndrome. Am J Ophthalmol Case Rep 2020; 18:100662. [PMID: 32274445 PMCID: PMC7132148 DOI: 10.1016/j.ajoc.2020.100662] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 11/05/2019] [Accepted: 03/09/2020] [Indexed: 02/07/2023] Open
Abstract
Purpose To report 2 cases of pediatric vitreoretinal disease in the setting of Turner's syndrome. Observations A 4-year-old girl with Turner's syndrome was referred for evaluation of a tractional retinal detachment in the right eye. Fundoscopic examination disclosed temporal dragging of the macula in the right eye, and vascular nonperfusion in the right and left eyes. Genetic testing revealed a novel frameshift mutation in the LRP5 gene consistent with familial exudative vitreoretinopathy (FEVR). The patient was treated with laser. A 14-year-old girl with Turner's syndrome presented with nyctalopia. Dilated fundus exam disclosed peri-foveal pigmentary changes and peripheral bone spicules. Full-field electroretinography demonstrated decreased rod and cone responses, consistent with retinitis pigmentosa (RP). Conclusions and importance Vitreoretinal disease, including RP and FEVR, is rarely observed in patients with Turner's syndrome.
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17
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RPGR-Associated Dystrophies: Clinical, Genetic, and Histopathological Features. Int J Mol Sci 2020; 21:ijms21030835. [PMID: 32012938 PMCID: PMC7038140 DOI: 10.3390/ijms21030835] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/21/2020] [Accepted: 01/27/2020] [Indexed: 12/11/2022] Open
Abstract
This study describes the clinical, genetic, and histopathological features in patients with RPGR-associated retinal dystrophies. Nine male patients from eight unrelated families underwent a comprehensive ophthalmic examination. Additionally, the histopathology of the right eye from a patient with an end-stage cone-rod-dystrophy (CRD)/sector retinitis pigmentosa (RP) phenotype was examined. All RPGR mutations causing a CRD phenotype were situated in exon ORF15. The mean best-corrected visual acuity (BCVA, decimals) was 0.58 (standard deviation (SD)): 0.34; range: 0.05-1.13); and the mean spherical refractive error was -4.1 D (SD: 2.11; range: -1.38 to -8.19). Hyperautofluorescent rings were observed in six patients. Full-field electroretinography responses were absent in all patients. The visual field defects ranged from peripheral constriction to central islands. The mean macular sensitivity on microperimetry was 11.6 dB (SD: 7.8; range: 1.6-24.4) and correlated significantly with BCVA (r = 0.907; p = 0.001). A histological examination of the donor eye showed disruption of retinal topology and stratification, with a more severe loss found in the peripheral regions. Reactive gliosis was seen in the inner layers of all regions. Our study demonstrates the highly variable phenotype found in RPGR-associated retinal dystrophies. Therapies should be applied at the earliest signs of photoreceptor degeneration, prior to the remodeling of the inner retina.
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18
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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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19
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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: 38] [Impact Index Per Article: 7.6] [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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20
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Song C, Conlon TJ, Deng WT, Coleman KE, Zhu P, Plummer C, Mandapati S, Van Hoosear M, Green KB, Sonnentag P, Sharma AK, Timmers A, Robinson PM, Knop DR, Hauswirth WW, Chulay JD, Shearman MS, Ye GJ. Toxicology and Pharmacology of an AAV Vector Expressing Codon-Optimized RPGR in RPGR-Deficient Rd9 Mice. HUM GENE THER CL DEV 2019; 29:188-197. [PMID: 30280954 DOI: 10.1089/humc.2018.168] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Applied Genetic Technologies Corporation (AGTC) is developing a recombinant adeno-associated virus (rAAV) vector AGTC-501, also designated AAV2tYF-GRK1-RPGRco, to treat retinitis pigmentosa (RP) in patients with mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene. The vector contains a codon-optimized human RPGR cDNA (RPGRco) driven by a photoreceptor-specific promoter (G protein-coupled receptor kinase 1, GRK1) and is packaged in an AAV2 capsid with three surface tyrosine residues changed to phenylalanine (AAV2tYF). We conducted a safety and potency study of this vector administered by subretinal a injection in the naturally occurring RPGR-deficient Rd9 mouse model. Sixty Rd9 mice (20 per group) received a subretinal injection in the right eye of vehicle (control) or AAV2tYF-GRK1-RPGRco at one of two dose levels (4 × 108 or 4 × 109 vg/eye) and were followed for 12 weeks after injection. Vector injections were well tolerated, with no systemic toxicity. There was a trend towards reduced electroretinography b-wave amplitudes in the high vector dose group that was not statistically significant. There were no clinically important changes in hematology or clinical chemistry parameters and no vector-related ocular changes in life or by histological examination. Dose-dependent RPGR protein expression, mainly in the inner segment of photoreceptors and the adjacent connecting cilium region, was observed in all vector-treated eyes examined. Sequence integrity of the codon-optimized RPGR was confirmed by sequencing of PCR-amplified DNA, or cDNA reverse transcribed from total RNA extracted from vector-treated retinal tissues, and by sequencing of RPGR protein obtained from transfected HEK 293 cells. These results support the use of rAAV2tYF-GRK1-RPGRco in clinical studies in patients with XLRP caused by RPGR mutations.
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Affiliation(s)
- Chunjuan Song
- 1 Applied Genetic Technologies Corporation (AGTC), Alachua, FL
| | - Thomas J Conlon
- 2 CR Scientific and Compliance Consulting LLC, Gainesville, FL
| | - Wen-Tao Deng
- 3 Department of Ophthalmology, University of Florida, Gainesville, FL
| | - Kirsten E Coleman
- 3 Department of Ophthalmology, University of Florida, Gainesville, FL
| | - Ping Zhu
- 3 Department of Ophthalmology, University of Florida, Gainesville, FL
| | - Cayrn Plummer
- 3 Department of Ophthalmology, University of Florida, Gainesville, FL
| | | | | | - Kari B Green
- 4 Department of Chemistry, University of Florida, Gainesville, FL
| | | | | | - Adrian Timmers
- 1 Applied Genetic Technologies Corporation (AGTC), Alachua, FL
| | | | - David R Knop
- 1 Applied Genetic Technologies Corporation (AGTC), Alachua, FL
| | | | | | - Mark S Shearman
- 1 Applied Genetic Technologies Corporation (AGTC), Alachua, FL
| | - Guo-Jie Ye
- 1 Applied Genetic Technologies Corporation (AGTC), Alachua, FL
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21
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Kurata K, Hosono K, Hayashi T, Mizobuchi K, Katagiri S, Miyamichi D, Nishina S, Sato M, Azuma N, Nakano T, Hotta Y. X-linked Retinitis Pigmentosa in Japan: Clinical and Genetic Findings in Male Patients and Female Carriers. Int J Mol Sci 2019; 20:E1518. [PMID: 30917587 PMCID: PMC6470860 DOI: 10.3390/ijms20061518] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 03/23/2019] [Accepted: 03/25/2019] [Indexed: 12/18/2022] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is a type of severe retinal dystrophy, and female carriers of XLRP demonstrate markedly variable clinical severity. In this study, we aimed to elucidate the clinical findings of male patients with and female carriers of XLRP in a Japanese cohort and demonstrate the genetic contribution. Twelve unrelated families (13 male patients, 15 female carriers) harboring pathogenic mutations in RPGR or RP2 were included, and comprehensive ophthalmic examinations were performed. To identify potential pathogenic mutations, targeted next-generation sequencing was employed. Consequently, we identified 11 pathogenic mutations, of which five were novel. Six and five mutations were detected in RPGR and RP2, respectively. Only one mutation was detected in ORF15. Affected male patients with RP2 mutations tended to have lower visual function than those with RPGR mutations. Female carriers demonstrated varying visual acuities and visual fields. Among the female carriers, 92% had electroretinographical abnormalities and 63% had a radial autofluorescent pattern, and the carriers who had higher myopia showed worse visual acuity and more severe retinal degeneration. Our results expand the knowledge of the clinical phenotypes of male patients with and female carriers of XLRP and suggest the possibility that RP2 mutations are relatively highly prevalent in Japan.
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Affiliation(s)
- Kentaro Kurata
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
| | - Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, 3-19-18, Nishi-shimbashi, Minato-ku, Tokyo 105-8471, Japan.
| | - Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, 3-19-18, Nishi-shimbashi, Minato-ku, Tokyo 105-8471, Japan.
| | - Satoshi Katagiri
- Department of Ophthalmology, The Jikei University School of Medicine, 3-19-18, Nishi-shimbashi, Minato-ku, Tokyo 105-8471, Japan.
| | - Daisuke Miyamichi
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
| | - Sachiko Nishina
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo 157-8535, Japan.
| | - Miho Sato
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
| | - Noriyuki Azuma
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, 2-10-1, Okura, Setagaya-ku, Tokyo 157-8535, Japan.
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, 3-19-18, Nishi-shimbashi, Minato-ku, Tokyo 105-8471, Japan.
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, 1-20-1, Handayama, Higashi-ku, Hamamatsu, Shizuoka 431-3192, Japan.
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22
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Exploring the Variable Phenotypes of RPGR Carrier Females in Assessing their Potential for Retinal Gene Therapy. Genes (Basel) 2018; 9:genes9120643. [PMID: 30567410 PMCID: PMC6316369 DOI: 10.3390/genes9120643] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 11/27/2018] [Accepted: 12/13/2018] [Indexed: 11/16/2022] Open
Abstract
Inherited retinal degenerations are the leading cause of blindness in the working population. X-linked retinitis pigmentosa (XLRP), caused by mutations in the Retinitis pigmentosa GTPase regulator (RPGR) gene is one of the more severe forms, and female carriers of RPGR mutations have a variable presentation. A retrospective review of twenty-three female RPGR carriers aged between 8 and 76 years old was carried out using fundoscopy, autofluorescence imaging (AF), blue reflectance (BR) imaging and optical coherence tomography (OCT). Confirmation of the genetic mutation was obtained from male relatives or Sanger genetic sequencing. Fundus examination and AF demonstrate phenotypic variability in RPGR carriers. The genetic mutation appears indeterminate of the degree of change. We found four distinct classifications based on AF images to describe RPGR carriers; normal (N) representing normal or near-normal AF appearance (n = 1, 4%); radial (R) pattern reflex without pigmentary retinopathy (n = 14, 61%); focal (F) pigmentary retinopathy (n = 5, 22%) and; male (M) phenotype (n = 3, 13%). The phenotypes were precisely correlated in both eyes (rs = 1.0, p < 0.0001). Skewed X-inactivation can result in severely affected carrier females—in some cases indistinguishable from the male pattern and these patients should be considered for RPGR gene therapy. In the cases of the male (M) phenotype where the X-inactivation was skewed, the pattern was similar in both eyes, suggesting that the mechanism is not truly random but may have an underlying genetic basis.
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23
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Birtel J, Gliem M, Mangold E, Müller PL, Holz FG, Neuhaus C, Lenzner S, Zahnleiter D, Betz C, Eisenberger T, Bolz HJ, Charbel Issa P. Next-generation sequencing identifies unexpected genotype-phenotype correlations in patients with retinitis pigmentosa. PLoS One 2018; 13:e0207958. [PMID: 30543658 PMCID: PMC6292620 DOI: 10.1371/journal.pone.0207958] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 11/08/2018] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa (RP) is an inherited degenerative disease causing severe retinal dystrophy and visual impairment mainly with onset in infancy or adolescence. Targeted next-generation sequencing (NGS) has become an efficient tool to encounter the enormous genetic heterogeneity of diverse retinal dystrophies, including RP. To identify disease-causing mutations in unselected, consecutive RP patients, we conducted Sanger sequencing of genes commonly involved in the suspected genetic RP subtype, followed by targeted large-panel NGS if no mutation was identified, or NGS as primary analysis. A high (70%) detection rate of disease-causing mutations was achieved in a large cohort of 116 unrelated patients. About half (48%) of the solved RP cases were explained by mutations in four genes: RPGR, EYS, PRPF31 and USH2A. Overall, 110 different mutations distributed across 30 different genes were detected, and 46 of these mutations were novel. A molecular diagnosis was achieved in the majority (82–100%) of patients if the family history was suggestive for a particular mode of inheritance, but only in 60% in cases of sporadic RP. The diagnostic potential of extensive molecular analysis in a routine setting is also illustrated by the identification of unexpected genotype-phenotype correlations for RP patients with mutations in CRX, CEP290, RPGRIP1, MFSD8. Furthermore, we identified numerous mutations in autosomal dominant (PRPF31, PRPH2, CRX) and X-linked (RPGR) RP genes in patients with sporadic RP. Variants in RP2 and RPGR were also found in female RP patients with apparently sporadic or dominant disease. In summary, this study demonstrates that massively parallel sequencing of all known retinal dystrophy genes is a valuable diagnostic approach for RP patients.
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Affiliation(s)
- Johannes Birtel
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | - Martin Gliem
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | | | - Philipp L. Müller
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | - Frank G. Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
| | | | | | | | - Christian Betz
- Bioscientia Center for Human Genetics, Ingelheim, Germany
| | | | - Hanno J. Bolz
- Bioscientia Center for Human Genetics, Ingelheim, Germany
- Institute of Human Genetics, University Hospital of Cologne, Cologne, Germany
| | - Peter Charbel Issa
- Department of Ophthalmology, University of Bonn, Bonn, Germany
- Center for Rare Diseases Bonn (ZSEB), University of Bonn, Bonn, Germany
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, and Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- * E-mail:
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Takahashi VKL, Takiuti JT, Jauregui R, Tsang SH. Gene therapy in inherited retinal degenerative diseases, a review. Ophthalmic Genet 2018; 39:560-568. [PMID: 30040511 DOI: 10.1080/13816810.2018.1495745] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hereditary diseases of the retina represent a group of diseases with several heterogeneous mutations that have the common end result of progressive photoreceptor death leading to blindness. Retinal degenerations encompass multifactorial diseases such as age-related macular degeneration, Leber congenital amaurosis, Stargardt disease, and retinitis pigmentosa. Although there is currently no cure for degenerative retinal diseases, ophthalmology has been at the forefront of the development of gene therapy, which offers hope for the treatment of these conditions. This article will explore an overview of the clinical trials of gene supplementation therapy for retinal diseases that are underway or planned for the near future.
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Affiliation(s)
- Vitor K L Takahashi
- a Department of Ophthalmology , Columbia University , New York , NY , USA.,b Departments of Ophthalmology, Pathology & Cell Biology,Columbia Stem Cell Initiative, Institute of Human Nutrition , Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University , New York , NY , USA.,c Department of Ophthalmology , Federal University of São Paulo , São Paulo , Brazil
| | - Júlia T Takiuti
- a Department of Ophthalmology , Columbia University , New York , NY , USA.,b Departments of Ophthalmology, Pathology & Cell Biology,Columbia Stem Cell Initiative, Institute of Human Nutrition , Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University , New York , NY , USA.,d Division of Ophthalmology , University of São Paulo Medical School , São Paulo , Brazil
| | - Ruben Jauregui
- a Department of Ophthalmology , Columbia University , New York , NY , USA.,b Departments of Ophthalmology, Pathology & Cell Biology,Columbia Stem Cell Initiative, Institute of Human Nutrition , Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University , New York , NY , USA.,e Weill Cornell Medical College , New York , NY , USA
| | - Stephen H Tsang
- a Department of Ophthalmology , Columbia University , New York , NY , USA.,b Departments of Ophthalmology, Pathology & Cell Biology,Columbia Stem Cell Initiative, Institute of Human Nutrition , Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Columbia University , New York , NY , USA.,f Department of Pathology & Cell Biology, Stem Cell Initiative (CSCI), Institute of Human Nutrition, College of Physicians and Surgeons , Columbia University , New York , NY , USA
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25
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Rao KN, Zhang W, Li L, Anand M, Khanna H. Prenylated retinal ciliopathy protein RPGR interacts with PDE6δ and regulates ciliary localization of Joubert syndrome-associated protein INPP5E. Hum Mol Genet 2018; 25:4533-4545. [PMID: 28172980 DOI: 10.1093/hmg/ddw281] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 07/24/2016] [Accepted: 08/19/2016] [Indexed: 12/11/2022] Open
Abstract
Ciliary trafficking defects underlie the pathogenesis of severe human ciliopathies, including Joubert Syndrome (JBTS), Bardet-Biedl Syndrome, and some forms of retinitis pigmentosa (RP). Mutations in the ciliary protein RPGR (retinitis pigmentosa GTPase regulator) are common causes of RP-associated photoreceptor degeneration worldwide. While previous work has suggested that the localization of RPGR to cilia is critical to its functions, the mechanism by which RPGR and its associated cargo are trafficked to the cilia is unclear. Using proteomic and biochemical approaches, we show that RPGR interacts with two JBTS-associated ciliary proteins: PDE6δ (delta subunit of phosphodiesterase; a prenyl-binding protein) and INPP5E (inositol polyphosphate-5-phosphatase 5E). We find that PDE6δ binds selectively to the C-terminus of RPGR and that this interaction is critical for RPGR’s localization to cilia. Furthermore, we show that INPP5E associates with the N-terminus of RPGR and trafficking of INPP5E to cilia is dependent upon the ciliary localization of RPGR. These results implicate prenylation of RPGR as a critical modification for its localization to cilia and, in turn suggest that trafficking of INPP5E to cilia depends upon the interaction of RPGR with PDE6δ. Finally, our results implicate INPP5E, a novel RPGR-interacting protein, in the pathogenesis of RPGR-associated ciliopathies.
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Affiliation(s)
- Kollu N Rao
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA
| | - Wei Zhang
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA
| | - Linjing Li
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA
| | - Manisha Anand
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA
| | - Hemant Khanna
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA
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26
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Zhou Q, Yao F, Wang F, Li H, Chen R, Sui R. A heterozygous mutation in RPGR associated with X-linked retinitis pigmentosa in a patient with Turner syndrome mosaicism (45,X/46,XX). Am J Med Genet A 2017; 176:214-218. [PMID: 29135076 DOI: 10.1002/ajmg.a.38501] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 07/17/2017] [Accepted: 09/24/2017] [Indexed: 01/15/2023]
Abstract
Turner syndrome with retinitis pigmentosa (RP) is rare, with only three cases reported based on clinical examination alone. We summarized the 4-year follow-up and molecular findings in a 28-year-old patient with Turner syndrome and the typical features of short stature and neck webbing, who also had X-linked RP. Her main complaints were night blindness and progressive loss of vision since the age of 9 years. Ophthalmologic examination, optical coherent tomographic imaging, and visual electrophysiology tests showed classic manifestations of RP. The karyotype of peripheral blood showed mosaicism (45,X [72%]/46,XX[28%]). A novel heterozygous frameshift mutation (c.2403_2406delAGAG, p.T801fsX812) in the RP GTPase regulator (RPGR) gene was detected using next generation sequencing and validated by Sanger sequencing. We believe that this is the first report of X-linked RP in a patient with Turner syndrome associated with mosaicism, and an RPGR heterozygous mutation. We hypothesize that X-linked RP in this woman is not related to Turner syndrome, but may be a manifestation of the lack of a normal paternal X chromosome with intact but mutated RPGR.
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Affiliation(s)
- Qi Zhou
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Fengxia Yao
- Laboratory of Clinical Genetics, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Feng Wang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Hui Li
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
| | - Rui Chen
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas
| | - Ruifang Sui
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing, China
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27
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Analysis of RP2 and RPGR Mutations in Five X-Linked Chinese Families with Retinitis Pigmentosa. Sci Rep 2017; 7:44465. [PMID: 28294154 PMCID: PMC5353642 DOI: 10.1038/srep44465] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/08/2017] [Indexed: 11/08/2022] Open
Abstract
Mutations in RP2 and RPGR genes are responsible for the X-linked retinitis pigmentosa (XLRP). In this study, we analyzed the RP2 and RPGR gene mutations in five Han Chinese families with XLRP. An approximately 17Kb large deletion including the exon 4 and exon 5 of RP2 gene was found in an XLRP family. In addition, four frameshift mutations including three novel mutations of c.1059 + 1 G > T, c.2002dupC and c.2236_2237del CT, as well as a previously reported mutation of c.2899delG were detected in the RPGR gene in the other four families. Our study further expands the mutation spectrum of RP2 and RPGR, and will be helpful for further study molecular pathogenesis of XLRP.
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28
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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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29
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Rao KN, Zhang W, Li L, Ronquillo C, Baehr W, Khanna H. Ciliopathy-associated protein CEP290 modifies the severity of retinal degeneration due to loss of RPGR. Hum Mol Genet 2016; 25:2005-2012. [PMID: 26936822 DOI: 10.1093/hmg/ddw075] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/29/2016] [Indexed: 12/25/2022] Open
Abstract
Mutations in RPGR (retinitis pigmentosa GTPase regulator) are the most common cause of X-linked RP, a severe blindness disorder. RPGR mutations result in clinically variable disease with early- to late-onset phenotypic presentation. Molecular mechanisms underlying such heterogeneity are unclear. Here we show that phenotypic expression of Rpgr-loss in mice is influenced genetically by the loss of Cep290, a human ciliopathy gene. We found that Rpgrko/Y mice with a heterozygous hypomorphic allele of Cep290 (Cep290rd16/+) but not of a heterozygous null allele of Cep290 (Cep290null/+) or of other ciliopathy genes, Rpgrip1, Nphp1, Nphp4 and Nphp5, exhibit relatively early onset (by 3 months of age) retinal degeneration and dysfunction when compared with the onset at ∼7 months of age in the Rpgrko/Y mice. We also observed disorganized photoreceptor outer-segment morphology and defective trafficking of opsins in the Rpgrko/Y::Cep290rd16/+ mice. Together with a physical interaction between RPGR and the C-terminal domain of CEP290, our data suggest that RPGR and CEP290 genetically interact and highlight the involvement of hypomorphic alleles of genes as potential modifiers of heterogeneous retinal ciliopathies.
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Affiliation(s)
- Kollu N Rao
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA and
| | - Wei Zhang
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA and
| | - Linjing Li
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA and
| | - Cecinio Ronquillo
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Wolfgang Baehr
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Hemant Khanna
- Department of Ophthalmology, Horae Gene Therapy Center, UMASS Medical School, Worcester, MA, USA and
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30
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Hoffman DR, Hughbanks-Wheaton DK, Spencer R, Fish GE, Pearson NS, Wang YZ, Klein M, Takacs A, Locke KG, Birch DG. Docosahexaenoic Acid Slows Visual Field Progression in X-Linked Retinitis Pigmentosa: Ancillary Outcomes of the DHAX Trial. Invest Ophthalmol Vis Sci 2016; 56:6646-53. [PMID: 26469750 DOI: 10.1167/iovs.15-17786] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Docosahexaenoic acid (DHA) was supplemented in a single-site, placebo-controlled, randomized clinical trial designed to slow vision loss associated with X-linked retinitis pigmentosa (XLRP); the DHAX Trial. We previously reported no significant differences between supplemented and placebo groups in intent-to-treat analysis of primary ERG outcomes. Assessed herein are hypothesis-generating measures of ancillary visual function outcomes in participants fully adhering to trial protocol. METHODS Male participants with XLRP (range, 7-31 years) received 30 mg DHA/kg/d (n = 29) or placebo (n = 22) for 4 years. Visual outcomes were measured annually and red blood cell (RBC) DHA determined every 6 months. RESULTS Oral DHA supplementation increased mean RBC-DHA levels by 4-fold (P < 0.0001) over placebo. No group differences in progression were found for visual acuity (P = 0.11), shape discrimination (P = 0.18), or fundus appearance (P = 0.70). Optical coherence tomography (OCT) became available during year 2 of the trial; no group differences were seen in ellipsoid zone constriction (P = 0.87) over 2 years. Yearly rates of progression were reduced for dark-adapted thresholds (P = 0.06) and visual field sensitivity for foveal, macular, peripheral, total, and ellipsoid zone regions by DHA supplementation (P = 0.039, P = 0.031, P < 0.0001, P < 0.0001, and P = 0.033). Rates of visual field sensitivity decline were dependent on RBC-DHA (P = 0.046 to <0.0001). CONCLUSIONS Supplementation of DHA significantly elevated blood DHA levels and reduced the rate of progression in final dark-adapted thresholds and visual field sensitivity. From the relationship between RBC-DHA and the rate of field sensitivity loss, we can extrapolate that an RBC-DHA level of 17% could minimize the decline in field sensitivity. (ClinicalTrials.gov number, NCT00100230.)
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Affiliation(s)
- Dennis R Hoffman
- Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Dianna K Hughbanks-Wheaton
- Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Rand Spencer
- Texas Retina Associates, Dallas, Texas, United States
| | - Gary E Fish
- Texas Retina Associates, Dallas, Texas, United States
| | - N Shirlene Pearson
- Center for Teaching Excellence, Southern Methodist University, Dallas, Texas, United States
| | - Yi-Zhong Wang
- Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Martin Klein
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Alison Takacs
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Kirsten G Locke
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - David G Birch
- Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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31
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Ogino K, Oishi M, Oishi A, Morooka S, Sugahara M, Gotoh N, Kurimoto M, Yoshimura N. Radial fundus autofluorescence in the periphery in patients with X-linked retinitis pigmentosa. Clin Ophthalmol 2015; 9:1467-74. [PMID: 26316687 PMCID: PMC4544811 DOI: 10.2147/opth.s89371] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose To describe the peripheral autofluorescence images and clinical features of patients with retinal dystrophy who showed radial fundus autofluorescence (FAF) at the posterior pole. Methods The authors retrospectively reviewed pooled wide-field FAF images of 711 patients with retinal dystrophy and 56 family members. Results Eleven eyes of seven women exhibited radial FAF at the posterior pole. Wide-field FAF showed extension of the radial pattern to the periphery in all eyes except one. One woman showed radial hyper-FAF only in the periphery, not at the posterior pole. These eight individuals were X-linked retinitis pigmentosa patients or carriers. The tapetal-like reflex was not observed in their color fundus photographs. The peripheral visual field showed wedge-shaped restriction in some individuals. Conclusion Wide-field FAF imaging can depict radial FAF not only at the posterior pole but also in the periphery in X-linked retinitis pigmentosa carriers. The authors therefore agree with previous reports that radial FAF may be a hallmark of X-linked retinitis pigmentosa.
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Affiliation(s)
- Ken Ogino
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Maho Oishi
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Akio Oishi
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Satoshi Morooka
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masako Sugahara
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Norimoto Gotoh
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan ; Center for Genomic Medicine, Kyoto University, Kyoto, Japan
| | | | - Nagahisa Yoshimura
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Kyoto, Japan
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Deng WT, Dyka FM, Dinculescu A, Li J, Zhu P, Chiodo VA, Boye SL, Conlon TJ, Erger K, Cossette T, Hauswirth WW. Stability and Safety of an AAV Vector for Treating RPGR-ORF15 X-Linked Retinitis Pigmentosa. Hum Gene Ther 2015; 26:593-602. [PMID: 26076799 DOI: 10.1089/hum.2015.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Our collaborative successful gene replacement therapy using AAV vectors expressing a variant of human RPGR-ORF15 in two canine models provided therapeutic proof of concept for translation into human treatment. The ORF15 sequence contained within this AAV vector, however, has ORF15 DNA sequence variations compared to the published sequence that are likely due to its unusual composition of repetitive purine nucleotides. This mutability is a concern for AAV vector production and safety when contemplating a human trial. In this study, we establish the safety profile of AAV-hIRBP-hRPGR and AAV-hGRK1-hRPGR vectors used in the initial canine proof-of-principle experiments by demonstrating hRPGR-ORF15 sequence stability during all phases of manipulation, from plasmid propagation to vector production to its stability in vivo after subretinal administration to animals. We also evaluate potential toxicity in vivo by investigating protein expression, retinal structure and function, and vector biodistribution. Expression of hRPGR is detected in the inner segments and synaptic terminals of photoreceptors and is restricted to the connecting cilium when the vector is further diluted. Treated eyes exhibit no toxicity as assessed by retinal histopathology, immunocytochemistry, optical coherence tomography, fundoscopy, electroretinogram, and vector biodistribution. Therefore, the hRPGR-ORF15 variant in our AAV vectors appears to be a more stable form than the endogenous hRPGR cDNA when propagated in vitro. Its safety profile presented here in combination with its proven efficacy supports future gene therapy clinical trials.
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Affiliation(s)
- Wen-Tao Deng
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Frank M Dyka
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Astra Dinculescu
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Jie Li
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Ping Zhu
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Vince A Chiodo
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Sanford L Boye
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
| | - Thomas J Conlon
- 2 Powell Gene Therapy Center, Department of Pediatrics, University of Florida , Gainesville, Florida
| | - Kirsten Erger
- 2 Powell Gene Therapy Center, Department of Pediatrics, University of Florida , Gainesville, Florida
| | - Travis Cossette
- 2 Powell Gene Therapy Center, Department of Pediatrics, University of Florida , Gainesville, Florida
| | - William W Hauswirth
- 1 Department of Ophthalmology, College of Medicine, University of Florida , Gainesville, Florida
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Comander J, Weigel-DiFranco C, Sandberg MA, Berson EL. Visual Function in Carriers of X-Linked Retinitis Pigmentosa. Ophthalmology 2015; 122:1899-906. [PMID: 26143542 DOI: 10.1016/j.ophtha.2015.05.039] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Revised: 05/20/2015] [Accepted: 05/24/2015] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To determine the frequency and severity of visual function loss in female carriers of X-linked retinitis pigmentosa (XLRP). DESIGN Case series. PARTICIPANTS Two hundred seventy-six XLRP carriers with cross-sectional data (n = 242) and longitudinal data (n = 34; median follow-up, 16 years; follow-up range, 3-37 years). Half of the carriers were from RPGR- or RP2-genotyped families. METHODS Retrospective medical records review. MAIN OUTCOME MEASURES Visual acuities, visual field areas, final dark adaptation thresholds, and full-field electroretinography (ERG) responses to 0.5-Hz and 30-Hz flashes. RESULTS In genotyped families, 40% of carriers showed a baseline abnormality on at least 1 of 3 psychophysical tests. There was a wide range of function among carriers. For example, 3 of 121 (2%) genotyped carriers were legally blind because of poor visual acuity, some as young as 35 years. Visual fields were less affected than visual acuity. In all carriers, the average ERG amplitude to 30-Hz flashes was approximately 50% of normal, and the average exponential rate of amplitude loss over time was half that of XLRP males (3.7%/year vs. 7.4%/year, respectively). Among obligate carriers with affected fathers, sons, or both, 53 of 55 (96%) had abnormal baseline ERG results. Some carriers who initially had completely normal fundi in both eyes went on to experience moderately decreased vision, although not legal blindness. Among carriers with RPGR mutations, those with mutations in ORF15, compared with those in exons 1-14, had worse final dark adaptation thresholds and lower 0.5-Hz and 30-Hz ERG amplitudes. CONCLUSIONS Most carriers of XLRP had mildly or moderately reduced visual function but rarely became legally blind. In most cases, obligate carriers could be identified by ERG testing. Carriers of RPGR ORF15 mutations tended to have worse visual function than carriers of RPGR exon 1 through 14 mutations. Because XLRP carrier ERG amplitudes and decay rates over time were on average half of those of affected men, these observations were consistent with the Lyon hypothesis of random X-inactivation.
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Affiliation(s)
- Jason Comander
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, Massachusetts.
| | - Carol Weigel-DiFranco
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, Massachusetts
| | - Michael A Sandberg
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, Massachusetts
| | - Eliot L Berson
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Massachusetts Eye & Ear Infirmary, Harvard Medical School, Boston, Massachusetts
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Megaw RD, Soares DC, Wright AF. RPGR: Its role in photoreceptor physiology, human disease, and future therapies. Exp Eye Res 2015; 138:32-41. [PMID: 26093275 PMCID: PMC4553903 DOI: 10.1016/j.exer.2015.06.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 12/21/2022]
Abstract
Mammalian photoreceptors contain specialised connecting cilia that connect the inner (IS) to the outer segments (OS). Dysfunction of the connecting cilia due to mutations in ciliary proteins are a common cause of the inherited retinal dystrophy retinitis pigmentosa (RP). Mutations affecting the Retinitis Pigmentosa GTPase Regulator (RPGR) protein is one such cause, affecting 10-20% of all people with RP and the majority of those with X-linked RP. RPGR is located in photoreceptor connecting cilia. It interacts with a wide variety of ciliary proteins, but its exact function is unknown. Recently, there have been important advances both in our understanding of RPGR function and towards the development of a therapy. This review summarises the existing literature on human RPGR function and dysfunction, and suggests that RPGR plays a role in the function of the ciliary gate, which controls access of both membrane and soluble proteins to the photoreceptor outer segment. We discuss key models used to investigate and treat RPGR disease and suggest that gene augmentation therapy offers a realistic therapeutic approach, although important questions still remain to be answered, while cell replacement therapy based on retinal progenitor cells represents a more distant prospect.
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Affiliation(s)
- Roly D Megaw
- Scottish Centre for Regenerative Medicine, University of Edinburgh, 5 Little France Drive, Edinburgh EH16 4UU, United Kingdom.
| | - Dinesh C Soares
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom.
| | - Alan F Wright
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, United Kingdom.
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Schwarz N, Carr AJ, Lane A, Moeller F, Chen LL, Aguilà M, Nommiste B, Muthiah MN, Kanuga N, Wolfrum U, Nagel-Wolfrum K, da Cruz L, Coffey PJ, Cheetham ME, Hardcastle AJ. Translational read-through of the RP2 Arg120stop mutation in patient iPSC-derived retinal pigment epithelium cells. Hum Mol Genet 2015; 24:972-86. [PMID: 25292197 PMCID: PMC4986549 DOI: 10.1093/hmg/ddu509] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 09/29/2014] [Indexed: 01/08/2023] Open
Abstract
Mutations in the RP2 gene lead to a severe form of X-linked retinitis pigmentosa. RP2 patients frequently present with nonsense mutations and no treatments are currently available to restore RP2 function. In this study, we reprogrammed fibroblasts from an RP2 patient carrying the nonsense mutation c.519C>T (p.R120X) into induced pluripotent stem cells (iPSC), and differentiated these cells into retinal pigment epithelial cells (RPE) to study the mechanisms of disease and test potential therapies. RP2 protein was undetectable in the RP2 R120X patient cells, suggesting a disease mechanism caused by complete lack of RP2 protein. The RP2 patient fibroblasts and iPSC-derived RPE cells showed phenotypic defects in IFT20 localization, Golgi cohesion and Gβ1 trafficking. These phenotypes were corrected by over-expressing GFP-tagged RP2. Using the translational read-through inducing drugs (TRIDs) G418 and PTC124 (Ataluren), we were able to restore up to 20% of endogenous, full-length RP2 protein in R120X cells. This level of restored RP2 was sufficient to reverse the cellular phenotypic defects observed in both the R120X patient fibroblasts and iPSC-RPE cells. This is the first proof-of-concept study to demonstrate successful read-through and restoration of RP2 function for the R120X nonsense mutation. The ability of the restored RP2 protein level to reverse the observed cellular phenotypes in cells lacking RP2 indicates that translational read-through could be clinically beneficial for patients.
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Affiliation(s)
- Nele Schwarz
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Amanda-Jayne Carr
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Amelia Lane
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Fabian Moeller
- Johannes Gutenberg-University Muellerweg 6, 55099 Mainz, Germany and
| | - Li Li Chen
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mònica Aguilà
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Britta Nommiste
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Manickam N Muthiah
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK
| | - Naheed Kanuga
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Uwe Wolfrum
- Johannes Gutenberg-University Muellerweg 6, 55099 Mainz, Germany and
| | | | - Lyndon da Cruz
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK, Moorfields Eye Hospital, 162 City Road, London EC1V 2PD, UK
| | - Peter J Coffey
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
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Cai CX, Locke KG, Ramachandran R, Birch DG, Hood DC. A comparison of progressive loss of the ellipsoid zone (EZ) band in autosomal dominant and x-linked retinitis pigmentosa. Invest Ophthalmol Vis Sci 2014; 55:7417-22. [PMID: 25342618 DOI: 10.1167/iovs.14-15013] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE In patients with retinitis pigmentosa (RP), the inner segment ellipsoid zone (EZ; also known as the inner segment/outer segment [IS/OS] border) is a marker of the usable visual field at a given point in time and of the progression of the disease over time. Here we compare the change in the width per year of the EZ band in patients with autosomal dominant (ad) and x-linked (xl) RP. METHODS Using optical coherence tomography (OCT), 9-mm horizontal and vertical line scans through the fovea were obtained for one eye of 26 xlRP patients and 33 adRP patients. Scans were repeated on average 2.0 years later (range, 0.6-4.8 years). Using a manual segmentation procedure, the EZ band was delineated and its horizontal width (HW) and vertical width (VW) were determined. RESULTS The adRP and xlRP patients had similar initial EZ HW (xlRP: 11.8 ± 5.4°, adRP: 12.4 ± 6.3°, P = 0.69) and VW (xlRP: 8.5 ± 4.9°, adRP: 11.4 ± 7.1°, P = 0.09). However, between visits the absolute loss and percent loss of the EZ width per year was significantly greater for xlRP than adRP for both HW (xlRP: 1.0 ± 0.6°/y, 9.6 ± 5.6%/y; adRP: 0.4 ± 0.5°/y, 3.4 ± 5.4%/y; P < 0.001) and VW (xlRP: 0.8 ± 0.8°/y, 9.2 ± 8.9%/y; adRP: 0.3 ± 0.5°/y, 4.2 ± 6.4%/y; P < 0.01). There was a weak correlation between the loss of EZ width per year and the initial width for xlRP (r(2) = 0.17, P = 0.036), but no correlation for adRP (r(2) = 0.004, P = 0.73). The test-retest difference of EZ HW was 0.2 ± 0.5°. CONCLUSIONS The OCT data here support a faster rate of loss per year in the case of xlRP. (ClinicalTrials.gov number, NCT00100230.).
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Affiliation(s)
- Cindy X Cai
- College of Physicians and Surgeons, Columbia University, New York, New York, United States
| | - Kirsten G Locke
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | | | - David G Birch
- Retina Foundation of the Southwest, Dallas, Texas, United States Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Donald C Hood
- Department of Psychology, Columbia University, New York, New York, United States Department of Ophthalmology, Columbia University, New York, New York, United States
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Hughbanks-Wheaton DK, Birch DG, Fish GE, Spencer R, Pearson NS, Takacs A, Hoffman DR. Safety assessment of docosahexaenoic acid in X-linked retinitis pigmentosa: the 4-year DHAX trial. Invest Ophthalmol Vis Sci 2014; 55:4958-66. [PMID: 25015354 DOI: 10.1167/iovs.14-14437] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Docosahexaenoic acid (DHA) continues to be evaluated and recommended as treatment and prophylaxis for various diseases. We recently assessed efficacy of high-dose DHA supplementation to slow vision loss in patients with X-linked retinitis pigmentosa (XLRP) in a randomized clinical trial. Because DHA is a highly unsaturated fatty acid, it could serve as a target for free-radical induced oxidation, resulting in increased oxidative stress. Biosafety was monitored during the 4-year trial to determine whether DHA supplementation was associated with identifiable risks. METHODS Males (n = 78; 7-31 years) meeting entry criteria were enrolled. The modified intent-to-treat cohort (DHA = 33; placebo = 27) adhered to the protocol ≥ 1 year. Participants were randomized to an oral dose of 30 mg/kg/d DHA or placebo plus a daily multivitamin. Comprehensive metabolic analyses were assessed for group differences. Treatment-emergent adverse events including blood chemistry metabolites were recorded. RESULTS By year 4, supplementation elevated plasma and red blood cell-DHA 4.4- and 3.6-fold, respectively, compared with the placebo group (P < 0.00001). Over the trial duration, no significant differences between DHA and placebo groups were found for vitamin A, vitamin E, platelet aggregation, antioxidant activity, lipoprotein cholesterol, or oxidized LDL levels (all P > 0.14). Adverse events were transient and not considered severe (e.g., gastrointestinal [GI] irritability, blood chemistry alterations). One participant was unable to tolerate persistent GI discomfort. CONCLUSIONS Long-term, high-dose DHA supplementation to patients with XLRP was associated with limited safety risks in this 4-year trial. Nevertheless, GI symptoms should be monitored in all patients taking high dose DHA especially those with personal or family history of GI disturbances. (ClinicalTrials.gov number, NCT00100230.).
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Affiliation(s)
- Dianna K Hughbanks-Wheaton
- Retina Foundation of the Southwest, Dallas, Texas, United States Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - David G Birch
- Retina Foundation of the Southwest, Dallas, Texas, United States Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Gary E Fish
- Texas Retina Associates, Dallas, Texas, United States
| | - Rand Spencer
- Texas Retina Associates, Dallas, Texas, United States
| | - N Shirlene Pearson
- Pearson Statistical Consulting & Expert Testimony, Richardson, Texas, United States
| | - Alison Takacs
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Dennis R Hoffman
- Retina Foundation of the Southwest, Dallas, Texas, United States Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
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Shifera AS, Kay CN. Early-Onset X-Linked Retinitis Pigmentosa in a Heterozygous Female Harboring an Intronic Donor Splice Site Mutation in the Retinitis Pigmentosa GTPase Regulator Gene. Ophthalmic Genet 2014; 36:251-6. [PMID: 24428633 DOI: 10.3109/13816810.2013.879597] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To report a heterozygous female presenting with an early-onset and severe form of X-linked retinitis pigmentosa (XLRP). PATIENTS AND METHODS This is a case series presenting the clinical findings in a heterozygous female with XLRP and two of her family members. Fundus photography, fundus autofluorescence, ocular coherence tomography, and visual perimetry are presented. RESULTS The proband reported here is a heterozygous female who presented at the age of 8 years with an early onset and aggressive form of XLRP. The patient belongs to a four-generation family with a total of three affected females and four affected males. The patient was initially diagnosed with retinitis pigmentosa (RP) at the age of 4 years. Genetic testing identified a heterozygous donor splice site mutation in intron 1 (IVS1 + 1G > A) of the retinitis pigmentosa GTPase regulator gene. The father of the proband was diagnosed with RP when he was a young child. The sister of the proband, evaluated at the age of 6 years, showed macular pigmentary changes. CONCLUSIONS Although carriers of XLRP are usually asymptomatic or have a mild disease of late onset, the proband presented here exhibited an early-onset, aggressive form of the disease. It is not clear why some carrier females manifest a severe phenotype. A better understanding of the genetic processes involved in the penetrance and expressivity of XLRP in heterozygous females could assist in providing the appropriate counseling to affected families.
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Yang L, Yin X, Feng L, You D, Wu L, Chen N, Li A, Li G, Ma Z. Novel mutations of RPGR in Chinese retinitis pigmentosa patients and the genotype-phenotype correlation. PLoS One 2014; 9:e85752. [PMID: 24454928 PMCID: PMC3893273 DOI: 10.1371/journal.pone.0085752] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/30/2013] [Indexed: 11/19/2022] Open
Abstract
X-linked Retinitis Pigmentosa (XLRP) accounts for 10–20% of all RP cases, and represents the most severe subtype of this disease. Mutations in the Retinitis Pigmentosa GTPase Regulator (RPGR) gene are the most common causes of XLRP, accounting for over 70–75% of all XLRP cases. In this work, we analyzed all the exons of RPGR gene with Sanger sequencing in seven Chinese XLRP families, two of these with a provisional diagnosis of adRP but without male-to-male transmission. Three novel deletions (c.2233_34delAG; c.2236_37delGA and c.2403_04delAG) and two known nonsense mutations (c.851C→G and c.2260G→T) were identified in five families. Two novel deletions (c.2233_34delAG and c.2236_37delGA) resulted in the same frame shift (p.E746RfsX22), created similar phenotype in Family 3 and 4. The novel deletion (c.2403_04delAG; p.E802GfsX31) resulted in both XLRP and x-linked cone-rod dystrophy within the male patients of family 5, which suggested the presence of either genetic or environmental modifiers, or both, play a substantial role in disease expression. Genotype-phenotype correlation analysis suggested that (1) both patients and female carriers with mutation in Exon 8 (Family 1) manifest more severe disease than did those with ORF15 mutations (Family 2&3&4); (2) mutation close to downstream of ORF15 (Family 5) demonstrate the early preferential loss of cone function with moderate loss of rod function.
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Affiliation(s)
- Liping Yang
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, P. R. China
| | - Xiaobei Yin
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, P. R. China
| | - Lina Feng
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, P. R. China
| | - Debo You
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, P. R. China
| | - Lemeng Wu
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, P. R. China
| | - Ningning Chen
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, P. R. China
| | - Aijun Li
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, P. R. China
| | - Genlin Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, P. R. China
- * E-mail: (GL); (ZM)
| | - Zhizhong Ma
- Department of Ophthalmology, Peking University Third Hospital, Key Laboratory of Vision Loss and Restoration, Ministry of Education, Beijing, P. R. China
- * E-mail: (GL); (ZM)
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Raghupathy RK, McCulloch DL, Akhtar S, Al-Mubrad TM, Shu X. Pathogenesis of X-linked RP3: insights from animal models. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:477-85. [PMID: 24664734 DOI: 10.1007/978-1-4614-3209-8_61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Retinitis Pigmentosa (RP) is a genetically heterogeneous disorder characterized by rod and cone photoreceptor cell dysfunction. X-linked RP (XLRP) is one of the most severe forms of human retinal degeneration, as determined by age-of-set and progression, and accounts for six to 20 % of all RP cases. At least six XLRP loci have been identified, but RP3 is the major subtype of XLRP, accounting for 70 to 80 % of affected families. The RPGR gene is responsible for the RP3 form of XLRP and is mutated in 10-20 % of all RP patients. The pathogenesis of retinitis pigmentosa GTPase regulator (RPGR) mutant-causing RP is not clear, different animal models have been used to understand the pathogenesis of these diseases. In this brief review, we will summarize the functional characterization of RPGR and highlight recent studies in animal models, which will not only shed light on the disease mechanisms in XLRP but will also provide therapeutic strategies for RP treatment.
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Pyo Park S, Hwan Hong I, Tsang SH, Chang S. Cellular imaging demonstrates genetic mosaicism in heterozygous carriers of an X-linked ciliopathy gene. Eur J Hum Genet 2013; 21:1240-8. [PMID: 23443027 PMCID: PMC3798832 DOI: 10.1038/ejhg.2013.21] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Revised: 11/02/2012] [Accepted: 01/24/2013] [Indexed: 11/09/2022] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is the least common genetic type of retinitis pigmentosa; however, it has extremely devastating consequences to patients' activities of daily living. RPGR and RP2 genes expressed in the photoreceptor sensory cilia are predominantly implicated in XLRP; however, the interpretation of genetic mutations and their correlation with clinical phenotypes remain unknown, and the role of these genes in photoreceptor cilia function is not completely elucidated. Therefore, we evaluated structural characteristics in five female obligate carriers of XLRP by using state-of-the-art non-invasive imaging methods, including adaptive optics (AO) scanning laser ophthalmoscopy (SLO). In all five carriers examined, qualitative and quantitative analyses by AO SLO imaging revealed a mosaic pattern of cone disruption, even in the absence of visual symptoms, normal visual acuity and normal macular thickness, on optical coherence tomography and mildly subnormal full-field cone electroretinographic findings. As the technique is sensitive to the level of a single cone, the ability to visualize the cone cells in vivo should be especially useful in other retinal diseases. In addition, further investigation of XLRP carriers may yield insight into how cone structures change over time and ultimately enable understanding of the role of RPGR and RP2 in cone cell survival.
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Affiliation(s)
- Sung Pyo Park
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Ophthalmology, Kangdong Sacred Heart Hospital, Hallym University Medical Center, Seoul, South Korea
| | - In Hwan Hong
- Department of Ophthalmology, Kangdong Sacred Heart Hospital, Hallym University Medical Center, Seoul, South Korea
| | - Stephen H Tsang
- Department of Ophthalmology, Columbia University, New York, NY, USA
- Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | - Stanley Chang
- Department of Ophthalmology, Columbia University, New York, NY, USA
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Abstract
PURPOSE OF REVIEW To describe the entity of Lyonization in ocular eye diseases, along with its clinical and counseling implications. RECENT FINDINGS Several X-linked ocular diseases such as choroideremia, X-linked retinitis pigmentosa, and X-linked ocular albinism may have signs of Lyonization on ocular examination and diagnostic testing. These findings may aid in the proper diagnosis of ocular disease in both female carriers and their affected male relatives. SUMMARY Manifestations of Lyonization in the eye may help in the diagnosis of X-linked ocular diseases which may lead to accurate diagnosis, appropriate molecular genetic testing and genetic counseling.
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Gillespie RL, Hall G, Black GC. Genetic testing for inherited ocular disease: delivering on the promise at last? Clin Exp Ophthalmol 2013; 42:65-77. [PMID: 23845030 DOI: 10.1111/ceo.12159] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Accepted: 06/30/2013] [Indexed: 12/11/2022]
Abstract
Genetic testing is of increasing clinical utility for diagnosing inherited eye disease. Clarifying a clinical diagnosis is important for accurate estimation of prognosis, facilitating genetic counselling and management of families, and in the future will direct gene-specific therapeutic strategies. Often, precise diagnosis of genetic ophthalmic conditions is complicated by genetic heterogeneity, a difficulty that the so-called 'next-generation sequencing' technologies promise to overcome. Despite considerable counselling and ethical complexities, next-generation sequencing offers to revolutionize clinical practice. This will necessitate considerable adjustment to standard practice but has the power to deliver a personalized approach to genomic medicine for many more patients and enhance the potential for preventing vision loss.
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Affiliation(s)
- Rachel L Gillespie
- Centre for Genomic Medicine, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, MAHSC, Manchester, UK; Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre (MAHSC), Manchester, UK
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Bertelsen M, Jensen H, Larsen M, Lorenz B, Preising MN, Rosenberg T. Prevalence and Diagnostic Spectrum of Generalized Retinal Dystrophy in Danish Children. Ophthalmic Epidemiol 2013; 20:164-9. [DOI: 10.3109/09286586.2013.776692] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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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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Branham K, Othman M, Brumm M, Karoukis AJ, Atmaca-Sonmez P, Yashar BM, Schwartz SB, Stover NB, Trzupek K, Wheaton D, Jennings B, Ciccarelli ML, Jayasundera KT, Lewis RA, Birch D, Bennett J, Sieving PA, Andreasson S, Duncan JL, Fishman GA, Iannaccone A, Weleber RG, Jacobson SG, Heckenlively JR, Swaroop A. Mutations in RPGR and RP2 account for 15% of males with simplex retinal degenerative disease. Invest Ophthalmol Vis Sci 2012; 53:8232-7. [PMID: 23150612 DOI: 10.1167/iovs.12-11025] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE To determine the proportion of male patients presenting simplex retinal degenerative disease (RD: retinitis pigmentosa [RP] or cone/cone-rod dystrophy [COD/CORD]) with mutations in the X-linked retinal degeneration genes RPGR and RP2. METHODS Simplex males were defined as patients with no known affected family members. Patients were excluded if they had a family history of parental consanguinity. Blood samples from a total of 214 simplex males with a diagnosis of retinal degeneration were collected for genetic analysis. The patients were screened for mutations in RPGR and RP2 by direct sequencing of PCR-amplified genomic DNA. RESULTS We identified pathogenic mutations in 32 of the 214 patients screened (15%). Of the 29 patients with a diagnosis of COD/CORD, four mutations were identified in the ORF15 mutational hotspot of the RPGR gene. Of the 185 RP patients, three patients had mutations in RP2 and 25 had RPGR mutations (including 12 in the ORF15 region). CONCLUSIONS This study represents mutation screening of RPGR and RP2 in the largest cohort, to date, of simplex males affected with RP or COD/CORD. Our results demonstrate a substantial contribution of RPGR mutations to retinal degenerations, and in particular, to simplex RP. Based on our findings, we suggest that RPGR should be considered as a first tier gene for screening isolated males with retinal degeneration.
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Affiliation(s)
- Kari Branham
- Department of Ophthalmology and Visual Sciences, University of Michigan, Kellogg Eye Center, Ann Arbor, Michigan 48105, USA
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Huang WC, Wright AF, Roman AJ, Cideciyan AV, Manson FD, Gewaily DY, Schwartz SB, Sadigh S, Limberis MP, Bell P, Wilson JM, Swaroop A, Jacobson SG. RPGR-associated retinal degeneration in human X-linked RP and a murine model. Invest Ophthalmol Vis Sci 2012; 53:5594-608. [PMID: 22807293 DOI: 10.1167/iovs.12-10070] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE We investigated the retinal disease due to mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene in human patients and in an Rpgr conditional knockout (cko) mouse model. METHODS XLRP patients with RPGR-ORF15 mutations (n = 35, ages at first visit 5-72 years) had clinical examinations, and rod and cone perimetry. Rpgr-cko mice, in which the proximal promoter and first exon were deleted ubiquitously, were back-crossed onto a BALB/c background, and studied with optical coherence tomography and electroretinography (ERG). Retinal histopathology was performed on a subset. RESULTS Different patterns of rod and cone dysfunction were present in patients. Frequently, there were midperipheral losses with residual rod and cone function in central and peripheral retina. Longitudinal data indicated that central rod loss preceded peripheral rod losses. Central cone-only vision with no peripheral function was a late stage. Less commonly, patients had central rod and cone dysfunction, but preserved, albeit abnormal, midperipheral rod and cone vision. Rpgr-cko mice had progressive retinal degeneration detectable in the first months of life. ERGs indicated relatively equal rod and cone disease. At late stages, there was greater inferior versus superior retinal degeneration. CONCLUSIONS RPGR mutations lead to progressive loss of rod and cone vision, but show different patterns of residual photoreceptor disease expression. Knowledge of the patterns should guide treatment strategies. Rpgr-cko mice had onset of degeneration at relatively young ages and progressive photoreceptor disease. The natural history in this model will permit preclinical proof-of-concept studies to be designed and such studies should advance progress toward human therapy.
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Affiliation(s)
- Wei Chieh Huang
- Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
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Webb TR, Parfitt DA, Gardner JC, Martinez A, Bevilacqua D, Davidson AE, Zito I, Thiselton DL, Ressa JHC, Apergi M, Schwarz N, Kanuga N, Michaelides M, Cheetham ME, Gorin MB, Hardcastle AJ. Deep intronic mutation in OFD1, identified by targeted genomic next-generation sequencing, causes a severe form of X-linked retinitis pigmentosa (RP23). Hum Mol Genet 2012; 21:3647-54. [PMID: 22619378 DOI: 10.1093/hmg/dds194] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is genetically heterogeneous with two causative genes identified, RPGR and RP2. We previously mapped a locus for a severe form of XLRP, RP23, to a 10.71 Mb interval on Xp22.31-22.13 containing 62 genes. Candidate gene screening failed to identify a causative mutation, so we adopted targeted genomic next-generation sequencing of the disease interval to determine the molecular cause of RP23. No coding variants or variants within or near splice sites were identified. In contrast, a variant deep within intron 9 of OFD1 increased the splice site prediction score 4 bp upstream of the variant. Mutations in OFD1 cause the syndromic ciliopathies orofaciodigital syndrome-1, which is male lethal, Simpson-Golabi-Behmel syndrome type 2 and Joubert syndrome. We tested the effect of the IVS9+706A>G variant on OFD1 splicing in vivo. In RP23 patient-derived RNA, we detected an OFD1 transcript with the insertion of a cryptic exon spliced between exons 9 and 10 causing a frameshift, p.N313fs.X330. Correctly spliced OFD1 was also detected in patient-derived RNA, although at reduced levels (39%), hence the mutation is not male lethal. Our data suggest that photoreceptors are uniquely susceptible to reduced expression of OFD1 and that an alternative disease mechanism can cause XLRP. This disease mechanism of reduced expression for a syndromic ciliopathy gene causing isolated retinal degeneration is reminiscent of CEP290 intronic mutations that cause Leber congenital amaurosis, and we speculate that reduced dosage of correctly spliced ciliopathy genes may be a common disease mechanism in retinal degenerations.
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Affiliation(s)
- Tom R Webb
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
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Gene therapy rescues photoreceptor blindness in dogs and paves the way for treating human X-linked retinitis pigmentosa. Proc Natl Acad Sci U S A 2012; 109:2132-7. [PMID: 22308428 DOI: 10.1073/pnas.1118847109] [Citation(s) in RCA: 204] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Hereditary retinal blindness is caused by mutations in genes expressed in photoreceptors or retinal pigment epithelium. Gene therapy in mouse and dog models of a primary retinal pigment epithelium disease has already been translated to human clinical trials with encouraging results. Treatment for common primary photoreceptor blindness, however, has not yet moved from proof of concept to the clinic. We evaluated gene augmentation therapy in two blinding canine photoreceptor diseases that model the common X-linked form of retinitis pigmentosa caused by mutations in the retinitis pigmentosa GTPase regulator (RPGR) gene, which encodes a photoreceptor ciliary protein, and provide evidence that the therapy is effective. After subretinal injections of adeno-associated virus-2/5-vectored human RPGR with human IRBP or GRK1 promoters, in vivo imaging showed preserved photoreceptor nuclei and inner/outer segments that were limited to treated areas. Both rod and cone photoreceptor function were greater in treated (three of four) than in control eyes. Histopathology indicated normal photoreceptor structure and reversal of opsin mislocalization in treated areas expressing human RPGR protein in rods and cones. Postreceptoral remodeling was also corrected: there was reversal of bipolar cell dendrite retraction evident with bipolar cell markers and preservation of outer plexiform layer thickness. Efficacy of gene therapy in these large animal models of X-linked retinitis pigmentosa provides a path for translation to human treatment.
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