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Jiang Y, Zhou L, Wang Y, Ouyang J, Li S, Xiao X, Jia X, Wang J, Yi Z, Sun W, Jiao X, Wang P, Hejtmancik JF, Zhang Q. The Genetic Confirmation and Clinical Characterization of LOXL3-Associated MYP28: A Common Type of Recessive Extreme High Myopia. Invest Ophthalmol Vis Sci 2023; 64:14. [PMID: 36917121 PMCID: PMC10019489 DOI: 10.1167/iovs.64.3.24] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
Abstract
Purpose In previous studies, biallelic LOXL3 variants have been shown to cause autosomal recessive Stickler syndrome in one Saudi Arabian family or autosomal recessive early-onset high myopia (eoHM, MYP28) in two Chinese families. The current study aims to elucidate the clinical and genetic features of LOXL3-associated MYP28 in seven new families and two previously published families. Methods LOXL3 variants were detected based on the exome sequencing data of 8389 unrelated probands with various ocular conditions. Biallelic variants were identified through multiple online bioinformatic tools, comparative analysis, and co-segregation analysis. The available clinical data were summarized. Results Biallelic LOXL3 variants were exclusively identified in nine of 1226 families with eoHM but in none of the 7163 families without eoHM (P = 2.97 × 10-8, Fisher's exact test), including seven new and two previously reported families. Seven pathogenic variants were detected, including one nonsense (c.1765C>T/p.Arg589*), three frameshift (c.39dupG/p.Leu14Alafs*21; c.544delC/p.Leu182Cysfs*3, c.594delG/p.Gln199Lysfs*35), and three missense (c.371G>A/p.Cys124Tyr; c.1051G>A/p.Gly351Arg; c.1669G>A/p.Glu557Lys) variants. Clinical data of nine patients from nine unrelated families revealed myopia at the first visit at about 5 years of age, showing slow progression with age. Visual acuity at the last visit ranged from 0.04 to 0.9 (median age at last visit = 5 years, range 3.5-15 years). High myopic fundus changes, observed in all nine patients, were classified as tessellated fundus (C1) in five patients and diffuse choroidal atrophy (C2) in four patients. Electroretinograms showed mildly reduced cone responses and normal rod responses. Except for high myopia, no other specific features were shared by these patients. Conclusions Biallelic LOXL3 variants exclusively presenting in nine unrelated patients with eoHM provide firm evidence implicating MYP28, with an estimated prevalence of 7.3 × 10-3 in eoHM and of about 7.3 × 10-5 in the general population for LOXL3-associated eoHM. So far, MYP28 represents a common type of autosomal recessive extreme eoHM, with a frequency comparable to LRPAP1-associated MYP23.
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Affiliation(s)
- Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Lin Zhou
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Jiamin Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Junwen Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Zhen Yi
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xiaodong Jiao
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Rockville, Maryland, United States
| | - Panfeng Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - J Fielding Hejtmancik
- Ophthalmic Molecular Genetics Section, Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Rockville, Maryland, United States
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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Kannabiran C, Parameswarappa D, Jalali S. Genetics of Inherited Retinal Diseases in Understudied Populations. Front Genet 2022; 13:858556. [PMID: 35295952 PMCID: PMC8919366 DOI: 10.3389/fgene.2022.858556] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Accepted: 02/03/2022] [Indexed: 11/17/2022] Open
Abstract
Retinitis pigmentosa is one of the major forms of inherited retinal dystrophy transmitted in all Mendelian and non-Mendelian forms of inheritance. It involves the loss of retinal photoreceptor cells with severe loss of vision or blindness within the first 2 decades of life. RP occurs at a relatively high prevalence in India and is often associated with consanguinity in certain South Asian communities where this practice is customary. This review describes the studies that have been published with regard to genetics of retinitis pigmentosa in India and neighboring South Asian countries. These populations have been understudied in these aspects although to a variable degree from one country to another. Genetic studies on RP in India have been carried out with a range of methods aimed at detecting specific mutations, to screening of candidate genes or selected genomic regions, homozygosity mapping to whole genome sequencing. These efforts have led to a molecular genetic characterization of RP in Indian families. Similar studies on large extended families from Pakistan have provided insight into several novel genes underlying the pathogenesis of these diseases. The extreme degree of clinical and genetic heterogeneity of RP renders it challenging to identify the associated genes in these populations, and to translate the research output towards better management of the disease, as there are no unifying genetic features that are characteristic of any population so far.
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Affiliation(s)
- Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, Prof Brien Holden Eye Research Centre, Hyderabad, India.,L. V. Prasad Eye Institute, Hyderabad, India
| | - Deepika Parameswarappa
- L. V. Prasad Eye Institute, Hyderabad, India.,Smt Kannuri Santhamma Centre for Retina Vitreous Services, Hyderabad, India
| | - Subhadra Jalali
- L. V. Prasad Eye Institute, Hyderabad, India.,Smt Kannuri Santhamma Centre for Retina Vitreous Services, Hyderabad, India
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Sun W, Xiao X, Li S, Jia X, Zhang Q. A novel deep intronic COL2A1 mutation in a family with early-onset high myopia/ocular-only Stickler syndrome. Ophthalmic Physiol Opt 2020; 40:281-288. [PMID: 32196734 DOI: 10.1111/opo.12682] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 02/13/2020] [Indexed: 12/13/2022]
Abstract
PURPOSE To identify the genetic defect causing early-onset high myopia (eoHM)/ocular-only Stickler syndrome (ocular-STL) in a large Chinese family. METHODS Genomic DNA and clinical data from a four-generation family with eoHM/ocular-STL were collected. Whole-exome sequencing was performed on one affected member in initial screening. Linkage scan based on microsatellite markers was carried out initially from candidate loci associated with autosomal dominant eoHM and Stickler syndrome. Sanger sequencing was used to detect potential variants. The pathogenicity of candidate variants was evaluated using mini genes ex vivo. RESULTS Eight patients and five unaffected members in the family participated in the study, in which the patients had high myopia with other variable ocular phenotypes but without extraocular abnormalities. Whole exome sequencing did not detect any potential pathogenic variant in all genes known to associate with the disease. The eoHM/ocular-STL in the family was mapped to markers around COL2A1 by candidate loci linkage scan, with a maximum lod score of 3.31 for D12S1590 at θ = 0. A novel deep intronic variant, c.86-50C > G in intron 1 of COL2A1, was detected by Sanger sequencing and co-segregated with eoHM/ocular-STL in the family. Ex vivo splicing test using mini genes confirmed that the variant created a new splicing acceptor 49 bp before the canonical splicing site of exon 2, resulted in addition of 49 bp fragment in the transcript (from c.86-49 to c.86-1) and premature termination. CONCLUSIONS Linkage study, bioinformatics prediction, and ex vivo transcript analysis suggest a novel deep intronic variant adjacent to 5-prime of exon 2 of COL2A1, affecting exon 2 splicing, as a potential cause of ocular-STL in a large family. To our knowledge, this is the first report of an intronic variant around exon 2 as a cause of ocular-STL while a series of variants in the coding region of exon 2, a dispensable alternative-splicing exon for extraocular tissues, in COL2A1 have been reported to cause Stickler syndrome-related ocular phenotype alone.
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Affiliation(s)
- Wenmin Sun
- 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
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xiaoyun Jia
- 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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Terao R, Honjo M, Ueta T, Obinata H, Izumi T, Kurano M, Yatomi Y, Koso H, Watanabe S, Aihara M. Light Stress-Induced Increase of Sphingosine 1-Phosphate in Photoreceptors and Its Relevance to Retinal Degeneration. Int J Mol Sci 2019; 20:ijms20153670. [PMID: 31357484 PMCID: PMC6696268 DOI: 10.3390/ijms20153670] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Accepted: 07/24/2019] [Indexed: 12/22/2022] Open
Abstract
Sphingosine 1-phosphate (S1P) is a potent lipid mediator that modulates inflammation and angiogenesis. In this study, we investigated the possible involvement of S1P in the pathology of light-induced retinal degeneration in vivo and in vitro. The intracellular S1P and sphingosine kinase (SphK) activity in a photoreceptor cell line (661W cells) was significantly increased by exposure to light. The enhancement of SphK1 expression was dependent on illumination, and all-trans-retinal significantly promoted SphK1 expression. S1P treatment reduced protein kinase B (Akt) phosphorylation and increased the protein expression of cleaved caspase-3, and induced photoreceptor cell apoptosis. In vivo, light exposure enhanced the expression of SphK1 in the outer segments of photoreceptors. Intravitreal injection of a SphK inhibitor significantly suppressed the thinning of the outer nuclear layer and ameliorated the attenuation of the amplitudes of a-waves and b-waves of electroretinograms during light-induced retinal degeneration. These findings imply that light exposure induces the synthesis of S1P in photoreceptors by upregulating SphK1, which is facilitated by all-trans-retinal, causing retinal degeneration. Inhibition of this enhancement may be a therapeutic target of outer retinal degeneration, including age-related macular degeneration.
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Affiliation(s)
- Ryo Terao
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan
| | - Megumi Honjo
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan
| | - Takashi Ueta
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan
| | - Hideru Obinata
- Gunma University Initiative for Advanced Research (GIAR), 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
| | - Takashi Izumi
- Department of Biochemistry, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan
| | - Makoto Kurano
- Department of Clinical Laboratory Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Yutaka Yatomi
- Department of Clinical Laboratory Medicine, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Hideto Koso
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Sumiko Watanabe
- Division of Molecular and Developmental Biology, Institute of Medical Science, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Makoto Aihara
- Department of Ophthalmology, Graduate School of Medicine, Tokyo University, Tokyo 113-8654, Japan.
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Novel truncation mutations in MYRF cause autosomal dominant high hyperopia mapped to 11p12-q13.3. Hum Genet 2019; 138:1077-1090. [PMID: 31172260 PMCID: PMC6745028 DOI: 10.1007/s00439-019-02039-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 06/04/2019] [Indexed: 12/15/2022]
Abstract
High hyperopia is a common and severe form of refractive error. Genetic factors play important roles in the development of high hyperopia but the exact gene responsible for this condition is mostly unknown. We identified a large Chinese family with autosomal dominant high hyperopia. A genome-wide linkage scan mapped the high hyperopia to chromosome 11p12-q13.3, with maximum log of the odds scores of 4.68 at theta = 0 for D11S987. Parallel whole-exome sequencing detected a novel c.3377delG (p.Gly1126Valfs*31) heterozygous mutation in the MYRF gene within the linkage interval. Whole-exome sequencing in other 121 probands with high hyperopia identified additional novel mutations in MYRF within two other families: a de novo c.3274_3275delAG (p.Leu1093Profs*22) heterozygous mutation and a c.3194+2T>C heterozygous mutation. All three mutations are located in the C-terminal region of MYRF and are predicted to result in truncation of that portion. Two patients from two of the three families developed angle-closure glaucoma. These three mutations were present in neither the ExAC database nor our in-house whole-exome sequencing data from 3280 individuals. No other truncation mutations in MYRF were detected in the 3280 individuals. Knockdown of myrf resulted in small eye size in zebrafish. These evidence all support that truncation mutations in the C-terminal region of MYRF are responsible for autosomal dominant high hyperopia in these families. Our results may provide useful clues for further understanding the functional role of the C-terminal region of this critical myelin regulatory factor, as well as the molecular pathogenesis of high hyperopia and its associated angle-closure glaucoma.
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Li L, Jiao X, D’Atri I, Ono F, Nelson R, Chan CC, Nakaya N, Ma Z, Ma Y, Cai X, Zhang L, Lin S, Hameed A, Chioza BA, Hardy H, Arno G, Hull S, Khan MI, Fasham J, Harlalka GV, Michaelides M, Moore AT, Coban Akdemir ZH, Jhangiani S, Lupski JR, Cremers FPM, Qamar R, Salman A, Chilton J, Self J, Ayyagari R, Kabir F, Naeem MA, Ali M, Akram J, Sieving PA, Riazuddin S, Baple EL, Riazuddin SA, Crosby AH, Hejtmancik JF. Mutation in the intracellular chloride channel CLCC1 associated with autosomal recessive retinitis pigmentosa. PLoS Genet 2018; 14:e1007504. [PMID: 30157172 PMCID: PMC6133373 DOI: 10.1371/journal.pgen.1007504] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 09/11/2018] [Accepted: 06/21/2018] [Indexed: 02/07/2023] Open
Abstract
We identified a homozygous missense alteration (c.75C>A, p.D25E) in CLCC1, encoding a presumptive intracellular chloride channel highly expressed in the retina, associated with autosomal recessive retinitis pigmentosa (arRP) in eight consanguineous families of Pakistani descent. The p.D25E alteration decreased CLCC1 channel function accompanied by accumulation of mutant protein in granules within the ER lumen, while siRNA knockdown of CLCC1 mRNA induced apoptosis in cultured ARPE-19 cells. TALEN KO in zebrafish was lethal 11 days post fertilization. The depressed electroretinogram (ERG) cone response and cone spectral sensitivity of 5 dpf KO zebrafish and reduced eye size, retinal thickness, and expression of rod and cone opsins could be rescued by injection of wild type CLCC1 mRNA. Clcc1+/- KO mice showed decreased ERGs and photoreceptor number. Together these results strongly suggest that intracellular chloride transport by CLCC1 is a critical process in maintaining retinal integrity, and CLCC1 is crucial for survival and function of retinal cells.
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Affiliation(s)
- Lin Li
- Department of Ophthalmology, Shanghai Ninth People’s Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, P.R. China
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xiaodong Jiao
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Ilaria D’Atri
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Fumihito Ono
- Section on Model Synaptic Systems, Laboratory of Molecular Physiology, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, Maryland, United States of America
- Department of Physiology, Osaka Medical College, Takatsuki, Japan
| | - Ralph Nelson
- Unit on Neural Circuits, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Chi-Chao Chan
- Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Naoki Nakaya
- Section of Molecular Mechanisms of Glaucoma, Laboratory of Molecular and Developmental Biology, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Yan Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xiaoying Cai
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P.R. China
| | - Longhua Zhang
- School of Life Sciences, University of Science and Technology of China, Hefei, Anhui, P.R. China
| | - Siying Lin
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Abdul Hameed
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
- Institute of Biomedical and Genetic Engineering (IBGE), Islamabad, Pakistan
| | - Barry A. Chioza
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Holly Hardy
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Gavin Arno
- Institute of Ophthalmology, University College London, London, United Kingdom
- Department of Biosciences, Moorfields Eye Hospital, London, United Kingdom
| | - Sarah Hull
- Institute of Ophthalmology, University College London, London, United Kingdom
- Department of Biosciences, Moorfields Eye Hospital, London, United Kingdom
| | - Muhammad Imran Khan
- Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - James Fasham
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
- Department of Clinical Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Gaurav V. Harlalka
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Michel Michaelides
- Institute of Ophthalmology, University College London, London, United Kingdom
- Department of Biosciences, Moorfields Eye Hospital, London, United Kingdom
| | - Anthony T. Moore
- Institute of Ophthalmology, University College London, London, United Kingdom
- Department of Biosciences, Moorfields Eye Hospital, London, United Kingdom
- Ophthalmology Department, UCSF School of Medicine, San Francisco, California, United States of America
| | - Zeynep Hande Coban Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Shalini Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America
| | - James R. Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
- Texas Children’s Hospital, Houston, Texas, United States of America
| | - Frans P. M. Cremers
- Department of Human Genetics, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Raheel Qamar
- Faculty of Science, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Ahmed Salman
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - John Chilton
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - Jay Self
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Firoz Kabir
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Muhammad Ali
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
- National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Paul A. Sieving
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
- National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Emma L. Baple
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
- Department of Clinical Genetics, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - S. Amer Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Andrew H. Crosby
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Exeter, United Kingdom
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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The Rapid-Onset Chorioretinopathy Phenotype of ABCA4 Disease. Ophthalmology 2017; 125:89-99. [PMID: 28947085 DOI: 10.1016/j.ophtha.2017.07.019] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Revised: 07/20/2017] [Accepted: 07/21/2017] [Indexed: 12/16/2022] Open
Abstract
PURPOSE To characterize patients affected by a uniquely severe, rapid-onset chorioretinopathy (ROC) phenotype of ABCA4 disease. DESIGN Comparative cohort study. PARTICIPANTS Sixteen patients were selected from a large clinically diagnosed and genetically confirmed cohort (n = 300) of patients diagnosed with ABCA4 disease. MAIN OUTCOME MEASURES Phenotypic characteristics were assessed on color fundus photographs, short-wavelength autofluorescence (488-nm), and near-infrared autofluorescence (NIR-AF, 787-nm) images. Subfoveal thickness measurements were obtained from enhanced-depth imaging OCT. Generalized retinal function was determined with full-field electroretinogram (ffERG) testing, and lipofuscin accumulation was assessed by quantitative autofluorescence (qAF). RESULTS All patients exhibited advanced disease features, including pigment migration in the macula and retinal vessel attenuation at an early age, and reported a symptomatic onset, on average, at 7.4 years (average for ABCA4 disease is 21.9 years, P < 0.0001). Deterioration of the macula was observed to begin with an intense, homogeneous signal on short-wavelength autofluorescence, which corresponds to an attenuated NIR-AF signal and progresses to a patchy, coalescing pattern of chorioretinal atrophy within the subsequent decade. Measurement of choroidal thickness revealed a more rapid thinning of choriocapillaris with age of Sattler's layer compared with the rate in most other patients with ABCA4 disease (P < 0.001). Levels of qAF in the macula before atrophy were above both the 95% confidence intervals for healthy individuals and patients with Stargardt disease (STGD1) (>1000 qAF units). Severe attenuation of cone responses and notable decreases in rod responses were detected by ffERG. Sequencing of the ABCA4 gene revealed exclusively deleterious, null mutations, including stop codons; frameshift deletions; variants in canonical splice sites, which completely abolish splicing; and known deleterious missense alleles. CONCLUSIONS The ROC phenotype is a unique classification of ABCA4 disease, which is caused by deleterious null biallelic ABCA4 mutations and is characterized by the rapid deterioration of retinal pigment epithelium and photoreceptor layers in the macula and significant choroidal thinning within the first 2 decades of life.
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LI SHIQIANG, GUAN LIPING, FANG SHAOHUA, JIANG HUI, XIAO XUESHAN, YANG JIANHUA, WANG PANFENG, YIN YE, GUO XIANGMING, WANG JUN, ZHANG JIANGUO, ZHANG QINGJIONG. Exome sequencing reveals CHM mutations in six families with atypical choroideremia initially diagnosed as retinitis pigmentosa. Int J Mol Med 2014; 34:573-7. [DOI: 10.3892/ijmm.2014.1797] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Accepted: 05/30/2014] [Indexed: 11/06/2022] Open
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Khan MI, Azam M, Ajmal M, Collin RWJ, den Hollander AI, Cremers FPM, Qamar R. The molecular basis of retinal dystrophies in pakistan. Genes (Basel) 2014; 5:176-95. [PMID: 24705292 PMCID: PMC3978518 DOI: 10.3390/genes5010176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/14/2014] [Accepted: 02/14/2014] [Indexed: 12/23/2022] Open
Abstract
The customary consanguineous nuptials in Pakistan underlie the frequent occurrence of autosomal recessive inherited disorders, including retinal dystrophy (RD). In many studies, homozygosity mapping has been shown to be successful in mapping susceptibility loci for autosomal recessive inherited disease. RDs are the most frequent cause of inherited blindness worldwide. To date there is no comprehensive genetic overview of different RDs in Pakistan. In this review, genetic data of syndromic and non-syndromic RD families from Pakistan has been collected. Out of the 132 genes known to be involved in non-syndromic RD, 35 different genes have been reported to be mutated in families of Pakistani origin. In the Pakistani RD families 90% of the mutations causing non-syndromic RD and all mutations causing syndromic forms of the disease have not been reported in other populations. Based on the current inventory of all Pakistani RD-associated gene defects, a cost-efficient allele-specific analysis of 11 RD-associated variants is proposed, which may capture up to 35% of the genetic causes of retinal dystrophy in Pakistan.
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Affiliation(s)
- Muhammad Imran Khan
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Maleeha Azam
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Muhammad Ajmal
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen 6500 HB, The Netherlands.
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen 6500 HB, The Netherlands.
| | - Frans P M Cremers
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Raheel Qamar
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
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10
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Chen Y, Okano K, Maeda T, Chauhan V, Golczak M, Maeda A, Palczewski K. Mechanism of all-trans-retinal toxicity with implications for stargardt disease and age-related macular degeneration. J Biol Chem 2012; 287:5059-69. [PMID: 22184108 PMCID: PMC3281612 DOI: 10.1074/jbc.m111.315432] [Citation(s) in RCA: 184] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/17/2011] [Indexed: 12/14/2022] Open
Abstract
Compromised clearance of all-trans-retinal (atRAL), a component of the retinoid cycle, increases the susceptibility of mouse retina to acute light-induced photoreceptor degeneration. Abca4(-/-)Rdh8(-/-) mice featuring defective atRAL clearance were used to examine the one or more underlying molecular mechanisms, because exposure to intense light causes severe photoreceptor degeneration in these animals. Here we report that bright light exposure of Abca4(-/-)Rdh8(-/-) mice increased atRAL levels in the retina that induced rapid NADPH oxidase-mediated overproduction of intracellular reactive oxygen species (ROS). Moreover, such ROS generation was inhibited by blocking phospholipase C and inositol 1,4,5-trisphosphate-induced Ca(2+) release, indicating that activation occurs upstream of NADPH oxidase-mediated ROS generation. Because multiple upstream G protein-coupled receptors can activate phospholipase C, we then tested the effects of antagonists of serotonin 2A (5-HT(2A)R) and M(3)-muscarinic (M(3)R) receptors and found they both protected Abca4(-/-)Rdh8(-/-) mouse retinas from light-induced degeneration. Thus, a cascade of signaling events appears to mediate the toxicity of atRAL in light-induced photoreceptor degeneration of Abca4(-/-)Rdh8(-/-) mice. A similar mechanism may be operative in human Stargardt disease and age-related macular degeneration.
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MESH Headings
- ATP-Binding Cassette Transporters/genetics
- ATP-Binding Cassette Transporters/metabolism
- Alcohol Oxidoreductases/genetics
- Alcohol Oxidoreductases/metabolism
- Animals
- Calcium/metabolism
- Corneal Dystrophies, Hereditary/genetics
- Corneal Dystrophies, Hereditary/metabolism
- Corneal Dystrophies, Hereditary/pathology
- Humans
- Inositol 1,4,5-Trisphosphate/genetics
- Inositol 1,4,5-Trisphosphate/metabolism
- Light/adverse effects
- Macular Degeneration/genetics
- Macular Degeneration/metabolism
- Macular Degeneration/pathology
- Mice
- Mice, Knockout
- NADPH Oxidases/genetics
- NADPH Oxidases/metabolism
- Photoreceptor Cells, Vertebrate/metabolism
- Photoreceptor Cells, Vertebrate/pathology
- Reactive Oxygen Species/metabolism
- Receptor, Muscarinic M3/genetics
- Receptor, Muscarinic M3/metabolism
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Retinaldehyde/metabolism
- Serotonin 5-HT2 Receptor Antagonists/pharmacology
- Signal Transduction
- Type C Phospholipases/genetics
- Type C Phospholipases/metabolism
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Affiliation(s)
- Yu Chen
- From the Departments of Pharmacology and
| | | | - Tadao Maeda
- From the Departments of Pharmacology and
- Ophthalmology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965
| | - Vishal Chauhan
- From the Departments of Pharmacology and
- Ophthalmology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965
| | | | - Akiko Maeda
- From the Departments of Pharmacology and
- Ophthalmology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965
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11
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Maeda A, Golczak M, Chen Y, Okano K, Kohno H, Shiose S, Ishikawa K, Harte W, Palczewska G, Maeda T, Palczewski K. Primary amines protect against retinal degeneration in mouse models of retinopathies. Nat Chem Biol 2011; 8:170-8. [PMID: 22198730 PMCID: PMC3518042 DOI: 10.1038/nchembio.759] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 10/07/2011] [Indexed: 12/31/2022]
Abstract
Vertebrate vision is initiated by photoisomerization of the visual pigment chromophore 11-cis-retinal and is maintained by continuous regeneration of this retinoid through a series of reactions termed the retinoid cycle. However, toxic side reaction products, especially those involving reactive aldehyde groups of the photoisomerized product, all-trans-retinal, can cause severe retinal pathology. Here we lowered peak concentrations of free all-trans-retinal with primary amine-containing Food and Drug Administration (FDA)-approved drugs that did not inhibit chromophore regeneration in mouse models of retinal degeneration. Schiff base adducts between all-trans-retinal and these amines were identified by MS. Adducts were observed in mouse eyes only when an experimental drug protected the retina from degeneration in both short-term and long-term treatment experiments. This study demonstrates a molecular basis of all-trans-retinal-induced retinal pathology and identifies an assemblage of FDA-approved compounds with protective effects against this pathology in a mouse model that shows features of Stargardt's disease and age-related retinal degeneration.
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Affiliation(s)
- Akiko Maeda
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, USA
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12
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Xiao X, Li S, Guo X, Zhang Q. A novel locus for autosomal dominant congenital motor nystagmus mapped to 1q31-q32.2 between D1S2816 and D1S2692. Hum Genet 2011; 131:697-702. [PMID: 22065086 DOI: 10.1007/s00439-011-1113-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Accepted: 10/29/2011] [Indexed: 10/15/2022]
Abstract
Congenital motor nystagmus (CMN) is characterized by bilateral involuntary ocular oscillation without any other underlying ocular or systemic diseases. An autosomal dominant CMN was identified in a large Chinese family where all patients had nystagmus since infancy. The nystagmus in the family is independent of any known ocular or systemic diseases. After exclusion of known CMN loci, a genome-wide scan was performed by genotyping microsatellite markers at about 10 cM intervals, together with two-point linkage analysis. Exome sequencing was used to screen coding exons of well-annotated genes. Sanger-dideoxy sequencing was used to verify candidate variations inside the linkage interval. Congenital motor nystagmus in this family shows linkage to markers in a 11.39 Mb (12.1 cM) region on chromosome 1q31-q32.2 between D1S2816 and D1S2692. All nine markers in the linkage interval gave positive lod scores, with D1S2655 and D1S2636 yielding lod scores of 5.16 and 5.18, respectively, at θ = 0. No causative mutation in the linkage interval was identified by exome sequencing of gDNA from four patients. A linkage study of additional families and further analysis of candidate genes may ultimately lead to identification of the gene responsible for dominantly inherited CMN.
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Affiliation(s)
- Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060 Guangzhou, China.
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13
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Yuan Y, Zhou X, Wang F, Yan M, Ding F. Evidence for a novel autosomal dominant retinitis pigmentosa linked to chromosome 1p22.1-q12 in a Chinese family. Curr Eye Res 2011; 36:154-67. [PMID: 21281067 DOI: 10.3109/02713683.2010.511393] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To identify the causative genetic locus in a Chinese autosomal dominant retinitis pigmentosa (adRP) family that contained seven affected members in three generations. METHODS After clinical diagnosis and exclusion of all mapped genes and loci, the SLINK program was used to simulate the maximum logarithm of the likelihood ratio (LOD) score for a linkage study in this small family. A genome-wide scan was performed using microsatellite markers at 10 cM intervals. Two-point and multipoint LOD scores were calculated, and haplotypes were constructed. RESULTS The H11 family clinical presentation included an early onset of night blindness, a progressive loss of the peripheral visual field, typical retinitis pigmentosa (RP) fundus changes, and a cataract complication. A maximum two-point LOD score of 2.54 (θ = 0) was found at markers D1S2739, D1S457, D1S187, D1S189, and D1S305, and multipoint linkage analysis yielded a maximum LOD score of 2.54 for marker D1S187. These LOD scores were the closest to the maximum simulated LOD score. Haplotype analysis revealed that this form of adRP segregates with a 38.25 cM region that spanned 50 Mb on chromosome 1p22.1-q12. CONCLUSIONS Although this locus overlaps the RP19 locus caused by mutations in ABCA4 and the RP32 locus, both are inherited in an autosomal recessive mode rather than the autosomal dominant mode of inheritance found in the H11 family. The identification of this potential new locus for adRP further confirms the high level of heterogeneity for RP.
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Affiliation(s)
- Yuan Yuan
- Center for Gene Diagnosis, Zhongnan Hospital, Wuhan University, Wuhan, China
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14
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Ji Y, Wang J, Xiao X, Li S, Guo X, Zhang Q. Mutations in RPGR and RP2 of Chinese Patients with X-Linked Retinitis Pigmentosa. Curr Eye Res 2009; 35:73-9. [DOI: 10.3109/02713680903395299] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Yanli Ji
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, P. R. China
| | - Juan Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, P. R. China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, P. R. China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, P. R. China
| | - Xiangming Guo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, P. R. China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, P. R. China
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15
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Zhang Q, Zulfiqar F, Xiao X, Riazuddin SA, Ahmad Z, Caruso R, MacDonald I, Sieving P, Riazuddin S, Hejtmancik JF. Severe retinitis pigmentosa mapped to 4p15 and associated with a novel mutation in the PROM1 gene. Hum Genet 2007; 122:293-9. [PMID: 17605048 DOI: 10.1007/s00439-007-0395-2] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2007] [Accepted: 06/13/2007] [Indexed: 10/23/2022]
Abstract
Mutation in the PROM1 gene previously has been identified in one family with retinal degeneration for which neither ERG recordings nor detailed information about visual impairment is available. A large family with multiple individuals affected by retinal degeneration was ascertained in the Punjab province of Pakistan. The visual acuity of all affected patients in the family was severely compromised beginning in early childhood. The retinal disease in this family is a severe form of retinitis pigmentosa (RP) accompanied by macular degeneration. Fundus changes advanced with age. Choriocapillaris atrophy and posterior RPE atrophy were obvious allowing visualization of the large choroidal vessels in patients over 40 years of age. Rod and cone responses on ERG recordings were extinguished in patient's teens. A genome-wide scan mapped the disease to a 34.7 cM region of chromosome 4p14-p16 between D4S1599 and D4S405. A maximum lod score of 3.96 with D4S403 and D4S391 is seen at theta = 0. Sequence analysis of PROM1 located in the linkage interval identified a c.1726C>T homozygous transition in exon 15: resulting in p.Gln576X in the translated protein. This mutation is found in a homozygous state in all six affected individuals and was heterozygous in five of the six unaffected family members examined. The mutation was not detected in 192 chromosomes of unrelated control individuals of the same ethnicity and from the same region. This delineates the phenotypic characteristics of retinopathy caused by mutations in PROM1.
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Affiliation(s)
- Qingjiong Zhang
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20982, USA.
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16
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Barragán I, Abd El-Aziz MM, Borrego S, El-Ashry MF, O'Driscoll C, Bhattacharya SS, Antiñolo G. Linkage validation of RP25 Using the 10K genechip array and further refinement of the locus by new linked families. Ann Hum Genet 2007; 72:454-62. [PMID: 18510647 DOI: 10.1111/j.1469-1809.2008.00448.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Retinitis pigmentosa (RP) is a clinically and genetically heterogeneous group of retinal dystrophies, characterised by rod photoreceptor cell degeneration with autosomal recessive RP (arRP) as the commonest form worldwide. To date, a total of 26 loci have been reported for arRP, each having a prevalence of 1-5%, except for the RP25 locus which was identified as the genetic cause of 14% of arRP cases in Spain. In order to validate the original linkage of RP25, we undertook a total genome scan using the 10K GeneChip mapping array on three of the previously linked families. The data obtained supported the initial findings of linkage. Additionally, linkage analysis in 18 newly ascertained arRP families was performed using microsatellite markers spanning the chromosome 6p12.1-q15 interval. Five out of the 18 families showed suggestive evidence of linkage to RP25, hence supporting the high prevalence of this locus in the Spanish population. Furthermore, the finding of a crossover in one of these families is likely to have refined the disease interval from the original 16 cM to only a 2.67 cM region between D6S257 and D6S1557.
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Affiliation(s)
- I Barragán
- Unidad Clínica de Genética y Reproducción, Hospitales Universitarios Virgen del Rocío, Seville, Spain, and Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Seville, Spain
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17
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Travis GH, Golczak M, Moise AR, Palczewski K. Diseases caused by defects in the visual cycle: retinoids as potential therapeutic agents. Annu Rev Pharmacol Toxicol 2007; 47:469-512. [PMID: 16968212 PMCID: PMC2442882 DOI: 10.1146/annurev.pharmtox.47.120505.105225] [Citation(s) in RCA: 315] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Absorption of a photon by an opsin pigment causes isomerization of the chromophore from 11-cis-retinaldehyde to all-trans-retinaldehyde. Regeneration of visual chromophore following light exposure is dependent on an enzyme pathway called the retinoid or visual cycle. Our understanding of this pathway has been greatly facilitated by the identification of disease-causing mutations in the genes coding for visual cycle enzymes. Defects in nearly every step of this pathway are responsible for human-inherited retinal dystrophies. These retinal dystrophies can be divided into two etiologic groups. One involves the impaired synthesis of visual chromophore. The second involves accumulation of cytotoxic products derived from all-trans-retinaldehyde. Gene therapy has been successfully used in animal models of these diseases to rescue the function of enzymes involved in chromophore regeneration, restoring vision. Dystrophies resulting from impaired chromophore synthesis can also be treated by supplementation with a chromophore analog. Dystrophies resulting from the accumulation of toxic pigments can be treated pharmacologically by inhibiting the visual cycle, or limiting the supply of vitamin A to the eyes. Recent progress in both areas provides hope that multiple inherited retinal diseases will soon be treated by pharmaceutical intervention.
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Affiliation(s)
- Gabriel H. Travis
- Department of Ophthalmology, UCLA School of Medicine, Los Angeles, California 90095;
| | - Marcin Golczak
- Department of Pharmacology, Case School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965;
| | - Alexander R. Moise
- Department of Pharmacology, Case School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965;
| | - Krzysztof Palczewski
- Department of Pharmacology, Case School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965;
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18
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Abd El-Aziz MM, El-Ashry MF, Chan WM, Chong KL, Barragan I, Antiñolo G, Pang CP, Bhattacharya SS. A novel genetic study of Chinese families with autosomal recessive retinitis pigmentosa. Ann Hum Genet 2006; 71:281-94. [PMID: 17156103 DOI: 10.1111/j.1469-1809.2006.00333.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Autosomal recessive retinitis pigmentosa (arRP) is the commonest form of RP worldwide. To date 22 loci have been implicated in the pathogenesis of this disease; however none of these loci independently account for a significant proportion of recessive RP. Linkage studies of arRP in consanguineous families have been mainly based on homozygosity mapping, but this strategy cannot be applied in the case of non-consanguineous families. Therefore, we implemented a systematic approach for identifying the disease locus in three non-consanguineous Chinese families with arRP. Initially, linkage analysis using SNPs/microsatellite markers or mutation screening of known arRP genes excluded all loci/genes except RP25 on chromosome 6. Subsequently a whole genome scan for the three families using the 10K GeneChip Mapping Array was performed, in order to identify the possible disease locus. To the best of our knowledge this is the first report on the utilisation of the 10K GeneChip to study linkage in non-consanguineous Chinese arRP. This analysis indicates that the studied families are probably linked to the RP25 locus, a well defined arRP locus in other populations. The identification of another ethnic group linked to RP25 is highly suggestive that this represents a major locus for arRP.
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Affiliation(s)
- M M Abd El-Aziz
- Department of Molecular Genetics, Institute of Ophthalmology, London EC1V 9EL, UK.
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