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Gwack J, Kim N, Park J. Improving the Yield of Genetic Diagnosis through Additional Genetic Panel Testing in Hereditary Ophthalmic Diseases. Curr Issues Mol Biol 2024; 46:5010-5022. [PMID: 38785568 PMCID: PMC11119902 DOI: 10.3390/cimb46050300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2024] [Revised: 05/17/2024] [Accepted: 05/18/2024] [Indexed: 05/25/2024] Open
Abstract
Numerous hereditary ophthalmic diseases display significant genetic diversity. Consequently, the utilization of gene panel sequencing allows a greater number of patients to receive a genetic diagnosis for their clinical manifestations. We investigated how to improve the yield of genetic diagnosis through additional gene panel sequencing in hereditary ophthalmic diseases. A gene panel sequencing consisting of a customized hereditary retinopathy panel or hereditary retinitis pigmentosa (RP) panel was prescribed and referred to a CAP-accredited clinical laboratory. If no significant mutations associated with hereditary retinopathy and RP were detected in either panel, additional gene panel sequencing was requested for research use, utilizing the remaining panel. After additional gene panel sequencing, a total of 16 heterozygous or homozygous variants were identified in 15 different genes associated with hereditary ophthalmic diseases. Of 15 patients carrying any candidate variants, the clinical symptoms could be tentatively accounted for by genetic mutations in seven patients. However, in the remaining eight patients, given the in silico mutation predictive analysis, variant allele frequency in gnomAD, inheritance pattern, and genotype-phenotype correlation, fully elucidating the clinical manifestations with the identified rare variant was challenging. Our study highlights the utility of gene panel sequencing in achieving accurate diagnoses for hereditary ophthalmic diseases and enhancing the diagnostic yield through additional gene panel sequencing. Thus, gene panel sequencing can serve as a primary tool for the genetic diagnosis of hereditary ophthalmic diseases, even in cases where a single genetic cause is suspected. With a deeper comprehension of the genetic mechanisms underlying these diseases, it becomes feasible.
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Affiliation(s)
- Jin Gwack
- Department of Preventive Medicine, Jeonbuk National University Medical School, Jeonju 54907, Republic of Korea;
| | - Namsu Kim
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju 54907, Republic of Korea;
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 54907, Republic of Korea
| | - Joonhong Park
- Department of Laboratory Medicine, Jeonbuk National University Medical School and Hospital, Jeonju 54907, Republic of Korea;
- Research Institute of Clinical Medicine of Jeonbuk National University-Biomedical Research Institute of Jeonbuk National University Hospital, Jeonju 54907, Republic of Korea
- Department of Laboratory Medicine, Daejeon St. Mary’s Hospital, Daejeon 34943, Republic of Korea
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Gocuk SA, Jolly JK, Edwards TL, Ayton LN. Female carriers of X-linked inherited retinal diseases - Genetics, diagnosis, and potential therapies. Prog Retin Eye Res 2023; 96:101190. [PMID: 37406879 DOI: 10.1016/j.preteyeres.2023.101190] [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: 03/09/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023]
Abstract
Inherited retinal diseases (IRDs) are a group of heterogeneous conditions that cause progressive vision loss, typically due to monogenic mutations. Female carriers of X-linked IRDs have a single copy of the disease-causing gene, and therefore, may exhibit variable clinical signs that vary from near normal retina to severe disease and vision loss. The relationships between individual genetic mutations and disease severity in X-linked carriers requires further study. This review summarises the current literature surrounding the spectrum of disease seen in female carriers of choroideremia and X-linked retinitis pigmentosa. Various classification systems are contrasted to accurately grade retinal disease. Furthermore, genetic mechanisms at the early embryonic stage are explored to potentially explain the variability of disease seen in female carriers. Future research in this area will provide insight into the association between genotype and retinal phenotypes of female carriers, which will guide in the management of these patients. This review acknowledges the importance of identifying which patients may be at high risk of developing severe symptoms, and therefore should be considered for emerging treatments, such as retinal gene therapy.
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Affiliation(s)
- Sena A Gocuk
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jasleen K Jolly
- Vision and Eye Research Institute, Anglia Ruskin University, Cambridge, UK
| | - Thomas L Edwards
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia.
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Marques JP, Pinheiro R, Carvalho AL, Raimundo M, Soares M, Melo P, Murta J, Saraiva J, Silva R. Genetic spectrum, retinal phenotype, and peripapillary RNFL thickness in RPGR heterozygotes. Graefes Arch Clin Exp Ophthalmol 2023; 261:867-878. [PMID: 36050475 DOI: 10.1007/s00417-022-05809-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 08/01/2022] [Accepted: 08/10/2022] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Phenotypic heterogeneity with variable severity has been reported in female carriers of retinitis pigmentosa GTPase regulator (RPGR) mutations, including a male-type phenotype. A phenomenon not fully understood is peripapillary retinal nerve fiber layer (pRNFL) thickening in male patients with RPGR-associated X-linked retinitis pigmentosa, especially in the temporal sector. We aim to describe the genetic spectrum, retinal phenotypes, and pRNFL thickness in a cohort of Caucasian RPGR-mutation heterozygotes. METHODS A cross-sectional study was conducted at an inherited retinal degeneration (IRD) reference center in Portugal. Female patients heterozygous for clinically significant RPGR variants were identified using the IRD-PT registry. A complete ophthalmologic examination was performed, complemented by macular and peripapillary spectral domain optical coherence tomography (SD-OCT), ultra-widefield color fundus photography (UW-CFP), and ultra-widefield fundus autofluorescence (UW-FAF). The retinal phenotypes were graded according to previously described classifications. The pRNFL thickness across the superior, inferior, nasal, and temporal quadrants was compared to the Spectralis® RNFL age-adjusted reference database. RESULTS Forty-eight eyes from 24 females (10 families) were included in the study. Genetic analysis yielded 8 distinct clinically significant frameshift variants in RPGR gene, 3 of which herein reported for the first time. No association was found between mutation location and best-corrected visual acuity (BCVA) or retinal phenotype. Age was associated with worse BCVA and more advanced phenotypes on SD-OCT, UW-CFP, and UW-FAF. Seven women (29.17%) presented a male-type phenotype on UW-FAF in at least one eye. An association was found between UW-FAF and pRNFL thickness in the temporal sector (p = 0.003), with the most advanced fundus autofluorescence phenotypes showing increased pRNFL thickness in this sector. CONCLUSION This study expands the genetic landscape of RPGR-associated disease by reporting 3 novel clinically significant variants. We have shown that clinically severe phenotypes are not uncommon among female carriers. Furthermore, we provide novel insights into pRNFL changes observed in RPGR heterozygotes that mimic what has been reported in male patients.
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Affiliation(s)
- João Pedro Marques
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal. .,Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal. .,University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal. .,Centro de Responsabilidade Integrado de Oftalmologia (CRIO), Centro Hospitalar e Universitário de Coimbra (CHUC), Praceta Prof. Mota Pinto, 3000-075, Coimbra, Portugal.
| | - Rosa Pinheiro
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
| | - Ana Luísa Carvalho
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.,Medical Genetics Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal.,University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Miguel Raimundo
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal.,Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.,University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Mário Soares
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
| | - Pedro Melo
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal
| | - Joaquim Murta
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal.,Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.,University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Jorge Saraiva
- Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.,University Clinic of Medical Genetics, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal.,University Clinic of Pediatrics, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Rufino Silva
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal.,Clinical Academic Center of Coimbra (CACC), Coimbra, Portugal.,University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
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Ahmad I. CRISPR/Cas9—A Promising Therapeutic Tool to Cure Blindness: Current Scenario and Future Prospects. Int J Mol Sci 2022; 23:ijms231911482. [PMID: 36232782 PMCID: PMC9569777 DOI: 10.3390/ijms231911482] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/24/2022] [Accepted: 09/26/2022] [Indexed: 11/16/2022] Open
Abstract
CRISPR-based targeted genome editing is bringing revolutionary changes in the research arena of biological sciences. CRISPR/Cas9 has been explored as an efficient therapeutic tool for the treatment of genetic diseases. It has been widely used in ophthalmology research by using mouse models to correct pathogenic mutations in the eye stem cells. In recent studies, CRISPR/Cas9 has been used to correct a large number of mutations related to inherited retinal disorders. In vivo therapeutic advantages for retinal diseases have been successfully achieved in some rodents. Current advances in the CRISPR-based gene-editing domain, such as modified Cas variants and delivery approaches have optimized its application to treat blindness. In this review, recent progress and challenges of the CRISPR-Cas system have been discussed to cure blindness and its prospects.
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Affiliation(s)
- Irshad Ahmad
- Department of Bioengineering, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia; ; Tel.: +966-13-8608393
- Interdisciplinary Research Center for Membranes and Water Security, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia
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Panikker P, Roy S, Ghosh A, Poornachandra B, Ghosh A. Advancing precision medicines for ocular disorders: Diagnostic genomics to tailored therapies. Front Med (Lausanne) 2022; 9:906482. [PMID: 35911417 PMCID: PMC9334564 DOI: 10.3389/fmed.2022.906482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Accepted: 06/29/2022] [Indexed: 11/20/2022] Open
Abstract
Successful sequencing of the human genome and evolving functional knowledge of gene products has taken genomic medicine to the forefront, soon combining broadly with traditional diagnostics, therapeutics, and prognostics in patients. Recent years have witnessed an extraordinary leap in our understanding of ocular diseases and their respective genetic underpinnings. As we are entering the age of genomic medicine, rapid advances in genome sequencing, gene delivery, genome surgery, and computational genomics enable an ever-increasing capacity to provide a precise and robust diagnosis of diseases and the development of targeted treatment strategies. Inherited retinal diseases are a major source of blindness around the world where a large number of causative genes have been identified, paving the way for personalized diagnostics in the clinic. Developments in functional genetics and gene transfer techniques has also led to the first FDA approval of gene therapy for LCA, a childhood blindness. Many such retinal diseases are the focus of various clinical trials, making clinical diagnoses of retinal diseases, their underlying genetics and the studies of natural history important. Here, we review methodologies for identifying new genes and variants associated with various ocular disorders and the complexities associated with them. Thereafter we discuss briefly, various retinal diseases and the application of genomic technologies in their diagnosis. We also discuss the strategies, challenges, and potential of gene therapy for the treatment of inherited and acquired retinal diseases. Additionally, we discuss the translational aspects of gene therapy, the important vector types and considerations for human trials that may help advance personalized therapeutics in ophthalmology. Retinal disease research has led the application of precision diagnostics and precision therapies; therefore, this review provides a general understanding of the current status of precision medicine in ophthalmology.
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Affiliation(s)
| | - Shomereeta Roy
- Grow Research Laboratory, Narayana Nethralaya Foundation, Bengaluru, India
| | - Anuprita Ghosh
- Grow Research Laboratory, Narayana Nethralaya Foundation, Bengaluru, India
| | | | - Arkasubhra Ghosh
- Grow Research Laboratory, Narayana Nethralaya Foundation, Bengaluru, India
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Schneider N, Sundaresan Y, Gopalakrishnan P, Beryozkin A, Hanany M, Levanon EY, Banin E, Ben-Aroya S, Sharon D. Inherited retinal diseases: Linking genes, disease-causing variants, and relevant therapeutic modalities. Prog Retin Eye Res 2021; 89:101029. [PMID: 34839010 DOI: 10.1016/j.preteyeres.2021.101029] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 12/11/2022]
Abstract
Inherited retinal diseases (IRDs) are a clinically complex and heterogenous group of visual impairment phenotypes caused by pathogenic variants in at least 277 nuclear and mitochondrial genes, affecting different retinal regions, and depleting the vision of affected individuals. Genes that cause IRDs when mutated are unique by possessing differing genotype-phenotype correlations, varying inheritance patterns, hypomorphic alleles, and modifier genes thus complicating genetic interpretation. Next-generation sequencing has greatly advanced the identification of novel IRD-related genes and pathogenic variants in the last decade. For this review, we performed an in-depth literature search which allowed for compilation of the Global Retinal Inherited Disease (GRID) dataset containing 4,798 discrete variants and 17,299 alleles published in 31 papers, showing a wide range of frequencies and complexities among the 194 genes reported in GRID, with 65% of pathogenic variants being unique to a single individual. A better understanding of IRD-related gene distribution, gene complexity, and variant types allow for improved genetic testing and therapies. Current genetic therapeutic methods are also quite diverse and rely on variant identification, and range from whole gene replacement to single nucleotide editing at the DNA or RNA levels. IRDs and their suitable therapies thus require a range of effective disease modelling in human cells, granting insight into disease mechanisms and testing of possible treatments. This review summarizes genetic and therapeutic modalities of IRDs, provides new analyses of IRD-related genes (GRID and complexity scores), and provides information to match genetic-based therapies such as gene-specific and variant-specific therapies to the appropriate individuals.
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Affiliation(s)
- Nina Schneider
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Yogapriya Sundaresan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Prakadeeswari Gopalakrishnan
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Avigail Beryozkin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Mor Hanany
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Erez Y Levanon
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel
| | - Shay Ben-Aroya
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, 5290002, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, 91120, Israel.
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7
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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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Nebbioso M, Franzone F, Lambiase A, La Cava M, Mallone F, Pizzuti A, Marchionni E. X-linked dominant RPGR gene mutation in a familial Coats angiomatosis. BMC Ophthalmol 2021; 21:37. [PMID: 33446141 PMCID: PMC7807486 DOI: 10.1186/s12886-020-01791-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 12/25/2020] [Indexed: 11/15/2022] Open
Abstract
Background Retinitis Pigmentosa (RP) is the most frequent retinal hereditary disease and every kind of transmission pattern has been described. The genetic etiology of RP is extremely heterogeneous and in the last few years the large application of Next Generation Sequencing (NGS) approaches improved the diagnostic yield, elucidating previously unexplained RP causes and new genotype-phenotype correlations. The objective of this study was to reevaluate a previously reported family affected by Coats’-type RP without genetic diagnosis and to describe the new genetic findings. Case presentation Cohort, prospective, and single-center observational family case. Three individuals of a family, consisting of a mother and four sons, with a Coats phenotype were revaluated after 25 years of clinical follow-up using visual acuity tests, ophthalmoscopy, Goldmann visual field, electroretinography (ERG), and spectral domain-optical coherence tomography (SD-OCT). Specifically, a RP NGS panel was performed on one member of the family and segregation analysis was required for the other affected and unaffected members. NGS analysis disclosed a RPGR (Retinitis Pigmentosa GTPase Regulator) gene truncating variant segregating with the phenotype in all the three affected members. RPGR mutations are reported as causative of an X-linked RP. Conclusions This is the first reported family with a Coats’-type RP associated to a RPGR mutation and segregating as a dominant X-linked disease, confirming the hypothesis of the genetic origin of this condition and expanding the phenotypic spectrum of diseases caused by RPGR gene mutations. The Authors suggest RPGR gene screening mutations in patients presenting this phenotype.
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Affiliation(s)
- Marcella Nebbioso
- Department of Sense Organs, Faculty of Medicine and Odontology, Sapienza University of Rome, p. le A. Moro 5, 00185, Rome, Italy
| | - Federica Franzone
- Department of Sense Organs, Faculty of Medicine and Odontology, Sapienza University of Rome, p. le A. Moro 5, 00185, Rome, Italy
| | - Alessandro Lambiase
- Department of Sense Organs, Faculty of Medicine and Odontology, Sapienza University of Rome, p. le A. Moro 5, 00185, Rome, Italy. .,Department of Sense Organs, Sapienza University of Rome, Viale del Policlinico 155, 00161, Rome, Italy.
| | - Maurizio La Cava
- Department of Sense Organs, Faculty of Medicine and Odontology, Sapienza University of Rome, p. le A. Moro 5, 00185, Rome, Italy
| | - Fabiana Mallone
- Department of Sense Organs, Faculty of Medicine and Odontology, Sapienza University of Rome, p. le A. Moro 5, 00185, Rome, Italy
| | - Antonio Pizzuti
- Department of Experimental Medicine, Faculty of Medicine and Odontology, Sapienza University of Rome, p. le A. Moro 5, 00185, Rome, Italy
| | - Enrica Marchionni
- Department of Experimental Medicine, Faculty of Medicine and Odontology, Sapienza University of Rome, p. le A. Moro 5, 00185, Rome, Italy
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Talib M, Boon CJF. Retinal Dystrophies and the Road to Treatment: Clinical Requirements and Considerations. Asia Pac J Ophthalmol (Phila) 2020; 9:159-179. [PMID: 32511120 PMCID: PMC7299224 DOI: 10.1097/apo.0000000000000290] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 04/01/2020] [Indexed: 12/15/2022] Open
Abstract
: Retinal dystrophies (RDs) comprise relatively rare but devastating causes of progressive vision loss. They represent a spectrum of diseases with marked genetic and clinical heterogeneity. Mutations in the same gene may lead to different diagnoses, for example, retinitis pigmentosa or cone dystrophy. Conversely, mutations in different genes may lead to the same phenotype. The age at symptom onset, and the rate and characteristics of peripheral and central vision decline, may vary widely per disease group and even within families. For most RD cases, no effective treatment is currently available. However, preclinical studies and phase I/II/III gene therapy trials are ongoing for several RD subtypes, and recently the first retinal gene therapy has been approved by the US Food and Drug Administration for RPE65-associated RDs: voretigene neparvovec-rzyl (Luxturna). With the rapid advances in gene therapy studies, insight into the phenotypic spectrum and long-term disease course is crucial information for several RD types. The vast clinical heterogeneity presents another important challenge in the evaluation of potential efficacy in future treatment trials, and in establishing treatment candidacy criteria. This perspective describes these challenges, providing detailed clinical descriptions of several forms of RD that are caused by genes of interest for ongoing and future gene or cell-based therapy trials. Several ongoing and future treatment options will be described.
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Affiliation(s)
- Mays Talib
- Department of Ophthalmology, Leiden, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden, The Netherlands
- Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, University of Amsterdam. Amsterdam, The Netherlands
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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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Talib M, van Schooneveld MJ, Van Cauwenbergh C, Wijnholds J, Ten Brink JB, Florijn RJ, Schalij-Delfos NE, Dagnelie G, van Genderen MM, De Baere E, Meester-Smoor MA, De Zaeytijd J, Cremers FPM, van den Born LI, Thiadens AA, Hoyng CB, Klaver CC, Leroy BP, Bergen AA, Boon CJF. The Spectrum of Structural and Functional Abnormalities in Female Carriers of Pathogenic Variants in the RPGR Gene. Invest Ophthalmol Vis Sci 2019; 59:4123-4133. [PMID: 30105367 DOI: 10.1167/iovs.17-23453] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to investigate the phenotype and long-term clinical course of female carriers of RPGR mutations. Methods This was a retrospective cohort study of 125 heterozygous RPGR mutation carriers from 49 families. Results Eighty-three heterozygotes were from retinitis pigmentosa (RP) pedigrees, 37 were from cone-/cone-rod dystrophy (COD/CORD) pedigrees, and 5 heterozygotes were from pedigrees with mixed RP/CORD or unknown diagnosis. Mutations were located in exon 1-14 and in ORF15 in 42 of 125 (34%) and 83 of 125 (66%) subjects, respectively. The mean age at the first examination was 34.4 years (range, 2.1 to 86.0 years). The median follow-up time in heterozygotes with longitudinal data (n = 62) was 12.2 years (range, 1.1 to 52.2 years). Retinal pigmentary changes were present in 73 (58%) individuals. Visual symptoms were reported in 51 (40%) cases. Subjects with both symptoms and pigmentary fundus changes were older than the other heterozygotes (P = 0.01) and had thinner foveal outer retinas (P = 0.006). Complete expression of the RP or CORD phenotype was observed in 29 (23%) heterozygotes, although usually in milder forms than in affected male relatives. Best-corrected visual acuity (BCVA) was <20/40 and <20/400 in at least one eye in 45 of 116 (39%) and 11 of 116 (9%) heterozygotes, respectively. Myopia was observed in 74 of 101 (73%) subjects and was associated with lower BCVA (P = 0.006). Increasing age was associated with lower BCVA (P = 0.002) and decreasing visual field size (P = 0.012; I4e isopter). Conclusions RPGR mutations lead to a phenotypic spectrum in female carriers, with myopia as a significantly aggravating factor. Complete disease expression is observed in some individuals, who may benefit from future (gene) therapeutic options.
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Affiliation(s)
- Mays Talib
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | | | - Caroline Van Cauwenbergh
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium.,Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Jan Wijnholds
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands
| | - Jacoline B Ten Brink
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, The Netherlands
| | - Ralph J Florijn
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, The Netherlands
| | | | - Gislin Dagnelie
- Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, United States
| | - Maria M van Genderen
- Bartiméus, Diagnostic Centre for Complex Visual Disorders, Zeist, The Netherlands
| | - Elfride De Baere
- Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium
| | | | - Julie De Zaeytijd
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Frans P M Cremers
- Department of Human Genetics and Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - Alberta A Thiadens
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Carel B Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Caroline C Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Bart P Leroy
- Department of Ophthalmology, Ghent University and Ghent University Hospital, Ghent, Belgium.,Center for Medical Genetics, Ghent University and Ghent University Hospital, Ghent, Belgium.,Ophthalmic Genetics & Visual Electrophysiology, Division of Ophthalmology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, United States
| | - Arthur A Bergen
- Department of Clinical Genetics, Amsterdam UMC, University of Amsterdam, The Netherlands.,The Netherlands Institute for Neuroscience (NIN-KNAW), Amsterdam, The Netherlands
| | - Camiel J F Boon
- Department of Ophthalmology, Leiden University Medical Center, Leiden, The Netherlands.,Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, The Netherlands
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12
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Singh M, Tyagi SC. Genes and genetics in eye diseases: a genomic medicine approach for investigating hereditary and inflammatory ocular disorders. Int J Ophthalmol 2018; 11:117-134. [PMID: 29376001 DOI: 10.18240/ijo.2018.01.20] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 10/31/2017] [Indexed: 12/27/2022] Open
Abstract
Past 25y have witnessed an exponential increase in knowledge and understanding of ocular diseases and their respective genetic underpinnings. As a result, scientists have mapped many genes and their variants that can influence vision and health of our eyes. Based on these findings, it is becoming clear that an early diagnosis employing genetic testing can help evaluate patients' conditions for instituting treatment plan(s) and follow-up care to avoid vision complications later. For example, knowing family history becomes crucial for inherited eye diseases as it can benefit members in family who may have similar eye diseases or predispositions. Therefore, gathering information from an elaborate examination along with complete assessment of past medical illness by ophthalmologists followed by consultation with geneticists can help create a roadmap for making diagnosis and treatment precise and beneficial. In this review, we present an update on ocular genomic medicine that we believe has tremendous potential towards unraveling genetic implications in ocular diseases and patients' susceptibilities. We also discuss translational aspects of genetic ophthalmology and genome engineering that may help advance molecular diagnostics and therapeutics.
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Affiliation(s)
- Mahavir Singh
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Suresh C Tyagi
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
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13
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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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Identification of novel X-linked gain-of-function RPGR-ORF15 mutation in Italian family with retinitis pigmentosa and pathologic myopia. Sci Rep 2016; 6:39179. [PMID: 27995965 PMCID: PMC5171904 DOI: 10.1038/srep39179] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 11/18/2016] [Indexed: 11/09/2022] Open
Abstract
The aim of this study was to describe a new pathogenic variant in the mutational hot spot exon ORF15 of retinitis pigmentosa GTPase regulator (RPGR) gene within an Italian family with X-linked retinitis pigmentosa (RP), detailing its distinctive genotype-phenotype correlation with pathologic myopia (PM). All members of this RP-PM family underwent a complete ophthalmic examination. The entire open reading frames of RPGR and retinitis pigmentosa 2 genes were analyzed by Sanger sequencing. A novel frame-shift mutation in exon ORF15 of RPGR gene (c.2091_2092insA; p.A697fs) was identified as hemizygous variant in the male proband with RP, and as heterozygous variant in the females of this pedigree who invariably exhibited symmetrical PM in both eyes. The c.2091_2092insA mutation coherently co-segregated with the observed phenotypes. These findings expand the spectrum of X-linked RP variants. Interestingly, focusing on Caucasian ethnicity, just three RPGR mutations are hitherto reported in RP-PM families: one of these is located in exon ORF15, but none appears to be characterized by a high penetrance of PM trait as observed in the present, relatively small, pedigree. The geno-phenotypic attributes of this heterozygosity suggest that gain-of-function mechanism could give rise to PM via a degenerative cell-cell remodeling of the retinal structures.
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Zhang Q. Genetics of Refraction and Myopia. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:269-79. [PMID: 26310160 DOI: 10.1016/bs.pmbts.2015.05.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Both genetic and environmental factors play roles in the development of refractive errors. Identification of genes involved in refractive errors may help in elucidating the underlying molecular mechanism related to both genetic defects and environmental pressure. Recent development of techniques for genome wide analysis provides unique opportunity in dissecting the genetic basis related to refractive errors. This chapter tries to give a brief overview on the recent progress of genetic study of refractive errors, especially myopia.
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Affiliation(s)
- Qingjiong Zhang
- State Key Lab of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, PR China.
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Tzu JH, Arguello T, Berrocal AM, Berrocal M, Weisman AD, Liu M, Hess D, Caputo M, Goldberg JL, Feuer WJ, Stone EM, Lam BL. Clinical and Electrophysiologic Characteristics of a Large Kindred with X-Linked Retinitis Pigmentosa Associated with the RPGR Locus. Ophthalmic Genet 2014; 36:321-6. [PMID: 24555744 DOI: 10.3109/13816810.2014.886267] [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 phenotypically and genotypically characterize a large Puerto Rican kindred with X-linked retinitis pigmentosa associated with a novel RP GTPase regulator (RPGR) genotype. METHODS A total of 100 family members of a single kindred with X-linked RP were evaluated with ophthalmic examinations and blood DNA analysis. Visual fields, OCT, and full-field ERG were obtained on all affected males and carriers. RESULTS Of the 100 family members examined, 13 were affected males and 18 were carriers. A deletion of 2 base pair of the RPGR gene in the ORF15 region at position c.2267-2268 (Lys756del2aaAG hemi) was identified with the affected and carriers. Best eye visual acuity was correlated with age (Spearman coefficient = 0.95) with hand-motion acuity by age 35 and light perception to no light perception by age 50-60. Visual fields were minimally plottable by age 40, and ERG responses reached non-detectable levels by late teens. Carriers had no or mild visual symptoms. All carriers had visual acuity of at least 20/50 or better in one eye, and the amount of retinal degeneration was variable with ERG responses ranging from severely impaired to normal. CONCLUSIONS Profound visual loss occurred by the second decade of life with progression to near no light perception by age 60 in this kindred of X-linked RP associated with the RPGR genotype. Female carriers maintained visual acuity with age and were identifiable by clinical and ERG examination. The information from this study is important to determine the optimal age for intervention, as new RP treatments are being developed and tested.
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Affiliation(s)
- Jonathan H Tzu
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - Tania Arguello
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - Audina M Berrocal
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | | | - Alejandra D Weisman
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - Mu Liu
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - Ditte Hess
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - Michelle Caputo
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - Jeffrey L Goldberg
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - William J Feuer
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
| | - Edwin M Stone
- c Department of Ophthalmology and Visual Sciences , University of Iowa , IA , USA , and.,d Howard Hughes Medical Institute, University of Iowa Carver College of Medicine , Iowa City , IA , USA
| | - Byron L Lam
- a Bascom Palmer Eye Institute, University of Miami Miller School of Medicine , Miami , FL , USA
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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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Zahid S, Khan N, Branham K, Othman M, Karoukis AJ, Sharma N, Moncrief A, Mahmood MN, Sieving PA, Swaroop A, Heckenlively JR, Jayasundera T. Phenotypic conservation in patients with X-linked retinitis pigmentosa caused by RPGR mutations. JAMA Ophthalmol 2013; 131:1016-25. [PMID: 23681342 DOI: 10.1001/jamaophthalmol.2013.120] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
IMPORTANCE For patients with X-linked retinitis pigmentosa and clinicians alike, phenotypic variability can be challenging because it complicates counseling regarding patients' likely visual prognosis. OBJECTIVE To evaluate the clinical findings from patients with X-linked retinitis pigmentosa with 13 distinct RPGR mutations and assess for phenotypic concordance or variability. DESIGN Retrospective medical record review of data collected from 1985 to 2011. SETTING Kellogg Eye Center, University of Michigan. PATIENTS A total of 42 patients with X-linked retinitis pigmentosa with mutations in RPGR. Age at first visit ranged from 4 to 53 years, with follow-up ranging from 1 to 11 visits (median follow-up time, 5.5 years; range, 1.4-32.7 years, for 23 patients with >1 visit). MAIN OUTCOMES AND MEASURES Clinical data assessed for concordance included visual acuity (VA), Goldmann visual fields (GVFs), and full-field electroretinography (ERG). Electroretinography phenotype (cone-rod vs rod-cone dysfunction) was defined by the extent of photopic vs scotopic abnormality. Qualitative GVF phenotype was determined by the GVF pattern, where central or peripheral loss suggested cone or rod dysfunction, respectively. Goldmann visual fields were also quantified and compared among patients. RESULTS Each mutation was detected in 2 or more related or unrelated patients. Five mutations in 11 patients displayed strong concordance of VA, while 4 mutations in 16 patients revealed moderate concordance of VA. A definitive cone-rod or rod-cone ERG pattern consistent among patients was found in 6 of 13 mutations (46.2%); the remaining mutations were characterized by patients demonstrating both phenotypes or who had limited data or nonrecordable ERG values. Concordant GVF phenotypes (7 rod-cone pattern vs 4 cone-rod pattern) were seen in 11 of 13 mutations (84.6%). All 6 mutations displaying a constant ERG pattern within the mutation group revealed a GVF phenotype consistent with the ERG findings. CONCLUSIONS AND RELEVANCE While VA and ERG phenotypes are concordant in only some patients carrying identical mutations, assessment of GVF phenotypes revealed stronger phenotypic conservation. Phenotypic concordance is important for establishing proper counseling of patients diagnosed as having X-linked retinitis pigmentosa, as well as for establishing accurate patient selection and efficacy monitoring in therapeutic trials.
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Affiliation(s)
- Sarwar Zahid
- Department of Ophthalmology and Visual Sciences, Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, 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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Abstract
PURPOSE To document the progression of disease in male and female members of a previously described family with X-linked dominant retinitis pigmentosa (RP) caused by a de novo insertion after nucleotide 173 in exon ORF15 of RPGR. METHODS The clinical records of 19 members of family UTAD054 were reviewed. Their evaluations consisted of confirmation of family history, standardised electroretinograms (ERGs), Goldmann visual fields, and periodic ophthalmological examinations over a 23-year period. RESULTS Male members of family UTAD054 had non-recordable to barely recordable ERGs from early childhood. The males showed contracted central fields and developed more severe retinopathy than the females. The female members showed a disease onset delayed to teenage years, recordable but diminishing photopic and scotopic ERG amplitudes in a cone-rod pattern, progressive loss and often asymmetric visual fields, and diffuse atrophic retinopathy with fewer pigment deposits compared with males. CONCLUSIONS This insertion mutation in the RPGR exon ORF15 is associated with a RP phenotype that severely affects males early and females by 30 years of age, and is highly penetrant in female members. Families with dominant-acting RPGR mutations may be mistaken to have an autosomal mode of inheritance resulting in an incorrect prediction of recurrence risk and prognosis. Broader recognition of X-linked RP forms with dominant inheritance is necessary to facilitate appropriate counselling of these patients.
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