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Chen X, Guo Y, Bi H, Liu X, Wu Y, Wang T, Li L, Lu W, Liu M, Wang Y. The Impact of Back Optic Zone Design in Orthokeratology on Visual Performance. Transl Vis Sci Technol 2024; 13:12. [PMID: 38758570 PMCID: PMC11107949 DOI: 10.1167/tvst.13.5.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 03/21/2024] [Indexed: 05/18/2024] Open
Abstract
Purpose To evaluate the visual performance in adolescents undergoing orthokeratology (OrthoK) treatment with two different optical zone diameters (OZDs). Methods This randomized, double-masked, self-controlled prospective study was conducted at Tianjin Eye Hospital (Tianjin, China) in June 2022. Thirty-six eligible schoolchildren were enrolled and fitted with corneal refractive therapy lenses with two sizes of OZDs (5 mm [5OZ] and 6 mm [6OZ]). Each participant was randomized to wear the 5OZ in one eye and the 6OZ in the contralateral eye. Subjective visual quality was assessed using visual acuity, refraction, contrast sensitivity function, and visual symptoms, and the objective optical quality was assessed using ocular higher order aberrations (HOAs) and modulation transfer function (MTF). Results Thirty-five myopic children completed a 1-month follow-up visit. The 5OZ lens induced significantly smaller treatment zone diameters than the 6OZ lens (P < 0.001). Subjective visual quality did not differ significantly between the two groups. Compared to baseline, aberrations of Z40, coma-like, spherical-like, and total HOAs in both groups increased significantly (P < 0.05). For the 3-mm pupils, spherical aberration in the 5OZ group was significantly higher than that in the 6OZ group (P < 0.05). The MTF value of the 6OZ group was significantly higher than that of 5OZ group for 0.3 and 1.5 cycles per degree for the 3-mm pupils (P = 0.006 and P = 0.026, respectively). However, HOAs or MTF did not differ significantly between the two groups for the 5-mm pupils. Conclusions The difference induced by varying OZD was significant only in the smaller pupil condition. The selection of OZD in OrthoK designs in real-world patient management should be done while considering individual pupil size. Translational Relevance This study revealed that the objective visual quality of small OZD lenses was only slightly affected for the small pupil size.
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Affiliation(s)
- Xiaoqin Chen
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
- Tianjin Eye Hospital Optometric Center, Tianjin, China
| | - Ying Guo
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
- Tianjin Eye Hospital Optometric Center, Tianjin, China
| | - Hua Bi
- College of Optometry, Nova Southeastern University, Davie, FL, USA
| | - Xuewei Liu
- Department of Epidemiology and Health Statistics, Tianjin Medical University, Tianjin, China
| | - Yiyuan Wu
- Tianjin Eye Hospital Optometric Center, Tianjin, China
| | - Ting Wang
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
- Tianjin Eye Hospital Optometric Center, Tianjin, China
| | - Lihua Li
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
- Tianjin Eye Hospital Optometric Center, Tianjin, China
| | - Wenli Lu
- Department of Epidemiology and Health Statistics, Tianjin Medical University, Tianjin, China
| | - Maria Liu
- School of Optometry, University of California, Berkeley, Berkeley, CA, USA
| | - Yan Wang
- Clinical College of Ophthalmology, Tianjin Medical University, Tianjin, China
- Tianjin Key Lab of Ophthalmology and Visual Science, Tianjin Eye Hospital, Tianjin, China
- Nankai University Eye Institute, Nankai University, Tianjin, China
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Georgiou M, Robson AG, Fujinami K, de Guimarães TAC, Fujinami-Yokokawa Y, Daich Varela M, Pontikos N, Kalitzeos A, Mahroo OA, Webster AR, Michaelides M. Phenotyping and genotyping inherited retinal diseases: Molecular genetics, clinical and imaging features, and therapeutics of macular dystrophies, cone and cone-rod dystrophies, rod-cone dystrophies, Leber congenital amaurosis, and cone dysfunction syndromes. Prog Retin Eye Res 2024; 100:101244. [PMID: 38278208 DOI: 10.1016/j.preteyeres.2024.101244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/28/2024]
Abstract
Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population and in children. The scope of this review is to familiarise clinicians and scientists with the current landscape of molecular genetics, clinical phenotype, retinal imaging and therapeutic prospects/completed trials in IRD. Herein we present in a comprehensive and concise manner: (i) macular dystrophies (Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), PRPH2-associated pattern dystrophy, Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)), (ii) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4, KCNV2 and RPGR), (iii) predominant rod or rod-cone dystrophies (retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)), (iv) Leber congenital amaurosis/early-onset severe retinal dystrophy (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (v) cone dysfunction syndromes (achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6), X-linked cone dysfunction with myopia and dichromacy (Bornholm Eye disease; OPN1LW/OPN1MW array), oligocone trichromacy, and blue-cone monochromatism (OPN1LW/OPN1MW array)). Whilst we use the aforementioned classical phenotypic groupings, a key feature of IRD is that it is characterised by tremendous heterogeneity and variable expressivity, with several of the above genes associated with a range of phenotypes.
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Affiliation(s)
- Michalis Georgiou
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
| | - Anthony G Robson
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Kaoru Fujinami
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.
| | - Thales A C de Guimarães
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Yu Fujinami-Yokokawa
- UCL Institute of Ophthalmology, University College London, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan; Department of Health Policy and Management, Keio University School of Medicine, Tokyo, Japan.
| | - Malena Daich Varela
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Nikolas Pontikos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Angelos Kalitzeos
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Omar A Mahroo
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom; Section of Ophthalmology, King s College London, St Thomas Hospital Campus, London, United Kingdom; Physiology, Development and Neuroscience, University of Cambridge, Downing Street, Cambridge, United Kingdom; Department of Translational Ophthalmology, Wills Eye Hospital, Philadelphia, PA, USA.
| | - Andrew R Webster
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom; UCL Institute of Ophthalmology, University College London, London, United Kingdom.
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Rappon J, Chung C, Young G, Hunt C, Neitz J, Neitz M, Chalberg T. Control of myopia using diffusion optics spectacle lenses: 12-month results of a randomised controlled, efficacy and safety study (CYPRESS). Br J Ophthalmol 2023; 107:1709-1715. [PMID: 36126105 PMCID: PMC10646852 DOI: 10.1136/bjo-2021-321005] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 08/16/2022] [Indexed: 12/29/2022]
Abstract
BACKGROUND Mutations in the L/M cone opsin gene array cause abnormally high perceived retinal contrast and the development of myopia. Environmental factors may also lead to high visual contrast and cause myopia. Diffusion optics technology (DOT) lenses are designed to reduce contrast signalling in the retina and slow myopia progression. METHODS The Control of Myopia Using Peripheral Diffusion Lenses Efficacy and Safety Study (CYPRESS, NCT03623074) is a 36-month, multicentre, randomised, controlled, double-masked trial evaluating two investigational spectacle lenses versus control lenses in myopic children aged 6-10, with a planned interim analysis at 12 months. The primary endpoints are change from baseline in axial length (AL) and spherical equivalent refraction (SER). RESULTS 256 children (58% female; mean age at screening, 8.1 years) were dispensed spectacles. Across all groups, baseline averages were AL 24.02 mm (SD±0.77 mm), SER -2.01 D (SD±0.9 D) using manifest refraction, and SER -1.94 D (SD±1.0 D) using cycloplegic autorefraction. At 12 months, mean difference in SER progression for test 1 versus control was -0.40 D (p<0.0001), representing a 74% reduction and -0.32 D for Test 2 (p<0.0001), representing a 59% reduction. The difference in AL progression for test 1 versus control was 0.15 mm (p<0.0001) and test 2 versus control was 0.10 mm (p=0.0018). CONCLUSION 12-month results from this ongoing trial demonstrate the safety and effectiveness of DOT spectacles for reducing myopic progression.
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Affiliation(s)
- Joe Rappon
- SightGlass Vision Inc, Palo Alto, California, USA
| | - Carol Chung
- Carol Chung Statistics Consulting Inc, Pacifica, California, USA
| | | | | | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, USA
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Farre AA, Sun C, Starostik MR, Hunter SS, English MA, Duncan A, Santhanam A, Shihabeddin E, O’Brien J, Swaroop A, Stenkamp DL. Long wavelength-sensing cones of zebrafish retina exhibit multiple layers of transcriptional heterogeneity. Front Cell Neurosci 2023; 17:1214084. [PMID: 37519633 PMCID: PMC10382231 DOI: 10.3389/fncel.2023.1214084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 06/26/2023] [Indexed: 08/01/2023] Open
Abstract
Introduction Understanding how photoreceptor genes are regulated is important for investigating retinal development and disease. While much is known about gene regulation in cones, the mechanism by which tandemly-replicated opsins, such as human long wavelength-sensitive and middle wavelength-sensitive opsins, are differentially regulated remains elusive. In this study, we aimed to further our understanding of transcriptional heterogeneity in cones that express tandemly-replicated opsins and the regulation of such differential expression using zebrafish, which express the tandemly-replicated opsins lws1 and lws2. Methods We performed bulk and single cell RNA-Seq of LWS1 and LWS2 cones, evaluated expression patterns of selected genes of interest using multiplex fluorescence in situ hybridization, and used exogenous thyroid hormone (TH) treatments to test selected genes for potential control by thyroid hormone: a potent, endogenous regulator of lws1 and lws2 expression. Results Our studies indicate that additional transcriptional differences beyond opsin expression exist between LWS1 and LWS2 cones. Bulk RNA-Seq results showed 95 transcripts enriched in LWS1 cones and 186 transcripts enriched in LWS2 cones (FC > 2, FDR < 0.05). In situ hybridization results also reveal underlying heterogeneity within the lws1- and lws2-expressing populations. This heterogeneity is evident in cones of mature zebrafish, and further heterogeneity is revealed in transcriptional responses to TH treatments. Discussion We found some evidence of coordinate regulation of lws opsins and other genes by exogenous TH in LWS1 vs. LWS2 cones, as well as evidence of gene regulation not mediated by TH. The transcriptional differences between LWS1 and LWS2 cones are likely controlled by multiple signals, including TH.
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Affiliation(s)
- Ashley A. Farre
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Chi Sun
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Margaret R. Starostik
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Samuel S. Hunter
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Milton A. English
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Audrey Duncan
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
| | - Abirami Santhanam
- Department of Vision Science, University of Houston College of Optometry, Houston, TX, United States
| | - Eyad Shihabeddin
- MD Anderson Cancer Center UTHealth Houston Graduate School of Biomedical Sciences, Houston, TX, United States
| | - John O’Brien
- Department of Vision Science, University of Houston College of Optometry, Houston, TX, United States
| | - Anand Swaroop
- Neurobiology-Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Deborah L. Stenkamp
- Department of Biological Sciences, University of Idaho, Moscow, ID, United States
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Breher K, Neumann A, Kurth D, Schaeffel F, Wahl S. ON and OFF receptive field processing in the presence of optical scattering. BIOMEDICAL OPTICS EXPRESS 2023; 14:2618-2628. [PMID: 37342711 PMCID: PMC10278613 DOI: 10.1364/boe.489117] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 06/23/2023]
Abstract
The balance of ON/OFF pathway activation in the retina plays a role in emmetropization. A new myopia control lens design uses contrast reduction to down-regulate a hypothesized enhanced ON contrast sensitivity in myopes. The study thus examined ON/OFF receptive field processing in myopes and non-myopes and the impact of contrast reduction. A psychophysical approach was used to measure the combined retinal-cortical output in the form of low-level ON and OFF contrast sensitivity with and without contrast reduction in 22 participants. ON responses were lower than OFF responses (ON 1.25 ± 0.03 vs. OFF 1.39 ± 0.03 log(CS); p < 0.0001) and myopes showed generally reduced sensitivities (myopes 1.25 ± 0.05 vs. non-myopes 1.39 ± 0.05 log(CS); p = 0.05). These findings remained unaffected by contrast reduction (p > 0.05). The study suggests that perceptual differences in ON and OFF signal processing between myopes and non-myopes exist but cannot explain how contrast reduction can inhibit myopia development.
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Affiliation(s)
- Katharina Breher
- Carl Zeiss Vision International GmbH, Turnstr. 27, 73430 Aalen, Germany
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tübingen, Germany
| | - Antonia Neumann
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tübingen, Germany
| | - Dominik Kurth
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tübingen, Germany
| | - Frank Schaeffel
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tübingen, Germany
- Institute of Molecular and Clinical Ophthalmology Basel, Mittlere Str. 91, 4056 Basel, Switzerland
| | - Siegfried Wahl
- Carl Zeiss Vision International GmbH, Turnstr. 27, 73430 Aalen, Germany
- Institute for Ophthalmic Research, University of Tübingen, Elfriede-Aulhorn-Str. 7, 72076 Tübingen, Germany
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Wang Y, Sun W, Xiao X, Jiang Y, Ouyang J, Wang J, Yi Z, Li S, Jia X, Wang P, Hejtmancik JF, Zhang Q. Unique Haplotypes in OPN1LW as a Common Cause of High Myopia With or Without Protanopia: A Potential Window Into Myopic Mechanism. Invest Ophthalmol Vis Sci 2023; 64:29. [PMID: 37097228 PMCID: PMC10148663 DOI: 10.1167/iovs.64.4.29] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
Purpose Specific haplotypes (LVAVA, LIVVA, and LIAVA) formed by five polymorphisms (p.L153M, p.V171I, p.A174V, p.I178V, and p.S180A in exon 3 of OPN1LW) that cause partial or complete exon skipping have been reported as unique genetic causes of high myopia with or without colorblindness. This study aimed to identify the contribution of OPN1LW to early-onset high myopia (eoHM) and the molecular basis underlying eoHM with or without colorblindness. Methods Comparative analysis of exome sequencing data was conducted for 1226 families with eoHM and 9304 families with other eye conditions. OPN1LW variants detected by targeted or whole exome sequencing were confirmed by long-range amplification and Sanger sequencing, together with segregation analysis. The clinical data were thoroughly analyzed. Results Unique haplotypes and truncation variants in OPN1LW were detected exclusively in 68 of 1226 families with eoHM but in none of the 9304 families with other visual diseases (P = 1.63 × 10-63). Four classes of variants were identified: haplotypes causing partial splicing defects in OPN1LW (LVAVA or LIVVA in 31 families), LVAVA in OPN1LW-OPN1MW hybrid gene (in 3 families), LIAVA in OPN1LW (in 29 families), and truncations in OPN1LW (in 5 families). The first class causes partial loss of red photopigments, whereas the latter three result in complete loss of red photopigments. This is different from the replacement of red with green owing to unequal re-arrangement causing red-green colorblindness alone. Of the 68 families, 42 affected male patients (31 families) with the first class of variants (LVAVA or LIVVA in OPN1LW) had eoHM alone, whereas 37 male patients with the latter 3 classes had eoHM with protanopia. Adaptive optics retinal imaging demonstrated reduced cone regularity and density in men with eoHM caused by OPN1LW variants compared to those patients with eoHM and without OPN1LW variants. Conclusion Based on the 68 families with unique variants in OPN1LW, our study provides firm evidence that the two different phenotypes (eoHM with or without colorblindness) are caused by two different classes of variants (partial splicing-effect haplotypes or complete splicing-effect haplotypes/truncation variants, respectively). The contribution of OPN1LW to eoHM (isolated and syndromic) was characterized by OPN1LW variants found in 5.5% (68/1226) of the eoHM families, making it the second most common cause of monogenic eoHM alone (2.4%) and a frequent cause of syndromic monogenic eoHM with colorblindness. Such haplotypes, in which each individual variant alone is considered a benign polymorphism, are potential candidates for other hereditary diseases with causes of missing genetic defects.
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Affiliation(s)
- 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
| | - 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
| | - 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
| | - 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
| | - 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
| | - 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
| | - 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
| | - 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
| | - 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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Applications of Genomics and Transcriptomics in Precision Medicine for Myopia Control or Prevention. Biomolecules 2023; 13:biom13030494. [PMID: 36979429 PMCID: PMC10046175 DOI: 10.3390/biom13030494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Revised: 02/18/2023] [Accepted: 03/02/2023] [Indexed: 03/12/2023] Open
Abstract
Myopia is a globally emerging concern accompanied by multiple medical and socio-economic burdens with no well-established causal treatment to control thus far. The study of the genomics and transcriptomics of myopia treatment is crucial to delineate disease pathways and provide valuable insights for the design of precise and effective therapeutics. A strong understanding of altered biochemical pathways and underlying pathogenesis leading to myopia may facilitate early diagnosis and treatment of myopia, ultimately leading to the development of more effective preventive and therapeutic measures. In this review, we summarize current data about the genomics and transcriptomics of myopia in human and animal models. We also discuss the potential applicability of these findings to precision medicine for myopia treatment.
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Hassan A, Mir YR, Kuchay RAH. Ocular findings and genomics of X-linked recessive disorders: A review. Indian J Ophthalmol 2022; 70:2386-2396. [PMID: 35791118 PMCID: PMC9426149 DOI: 10.4103/ijo.ijo_252_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Advent of new sequencing technologies and modern diagnostic procedures has opened the door for a deeper understanding of disorders about which little was known previously. Discovery of novel genes, new genetic variants in previously known genes and better techniques of functional validation has immensely contributed to unraveling the molecular basis of genetic disorders. Availability of knockout animal models like the zebrafish and gene editing tools like CRISPR-Cas9 has elucidated the function of many new genes and helped us to better understand the functional consequences of various gene defects. This has also led to better diagnosis and therapeutic interventions. In this context, a good body of research work has been done on X-linked recessive disorders with ocular findings. This review will focus on ocular and genetic findings of these rare disorders. To our knowledge, this is the first comprehensive review encompassing ocular and genomic spectrum of X-linked recessive disorders.
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Affiliation(s)
- Asima Hassan
- Department of Health and Medical Education, Srinagar, Jammu and Kashmir, India
| | - Yaser R Mir
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
| | - Raja A H Kuchay
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
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Stingl K, Baumann B, De Angeli P, Vincent A, Héon E, Cordonnier M, De Baere E, Raskin S, Sato MT, Shiokawa N, Kohl S, Wissinger B. Novel OPN1LW/OPN1MW Exon 3 Haplotype-Associated Splicing Defect in Patients with X-Linked Cone Dysfunction. Int J Mol Sci 2022; 23:ijms23126868. [PMID: 35743313 PMCID: PMC9224739 DOI: 10.3390/ijms23126868] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 06/15/2022] [Indexed: 02/01/2023] Open
Abstract
Certain combinations of common variants in exon 3 of OPN1LW and OPN1MW, the genes encoding the apo-protein of the long- and middle-wavelength sensitive cone photoreceptor visual pigments in humans, induce splicing defects and have been associated with dyschromatopsia and cone dysfunction syndromes. Here we report the identification of a novel exon 3 haplotype, G-C-G-A-T-T-G-G (referring to nucleotide variants at cDNA positions c.453, c.457, c.465, c.511, c.513, c.521, c.532, and c.538) deduced to encode a pigment with the amino acid residues L-I-V-V-A at positions p.153, p.171, p.174, p.178, and p.180, in OPN1LW or OPN1MW or both in a series of seven patients from four families with cone dysfunction. Applying minigene assays for all observed exon 3 haplotypes in the patients, we demonstrated that the novel exon 3 haplotype L-I-V-V-A induces a strong but incomplete splicing defect with 3-5% of residual correctly spliced transcripts. Minigene splicing outcomes were similar in HEK293 cells and the human retinoblastoma cell line WERI-Rb1, the latter retaining a cone photoreceptor expression profile including endogenous OPN1LW and OPN1MW gene expression. Patients carrying the novel L-I-V-V-A haplotype presented with a mild form of Blue Cone Monochromacy or Bornholm Eye Disease-like phenotype with reduced visual acuity, reduced cone electroretinography responses, red-green color vision defects, and frequently with severe myopia.
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Affiliation(s)
- Katarina Stingl
- Centre for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany;
| | - Britta Baumann
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
| | - Pietro De Angeli
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children and University of Toronto, Toronto, ON M5G 1X8, Canada; (A.V.); (E.H.)
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children and University of Toronto, Toronto, ON M5G 1X8, Canada; (A.V.); (E.H.)
| | - Monique Cordonnier
- Department of Ophthalmology, Hôpital Erasme, Cliniques Universitaires de Bruxelles, Université Libre de Bruxelles, 1070 Bruxelles, Belgium;
| | - Elfriede De Baere
- Center for Medical Genetics, Ghent University Hospital, Department of Biomolecular Medicine, Ghent University, 9000 Ghent, Belgium;
| | - Salmo Raskin
- Laboratório Genetika, Curitiba 80730-180, Brazil;
| | - Mario Teruo Sato
- Department of Ophthalmology & Otorhinolaryngology, Federal University of Paraná, Curitiba 80060-900, Brazil;
- Retina and Vitreo Consulting Eye Clinic, Curitiba 80530-010, Brazil;
| | - Naoye Shiokawa
- Retina and Vitreo Consulting Eye Clinic, Curitiba 80530-010, Brazil;
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, 72076 Tübingen, Germany; (B.B.); (P.D.A.); (S.K.)
- Correspondence:
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10
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Neitz M, Wagner-Schuman M, Rowlan JS, Kuchenbecker JA, Neitz J. Insight from OPN1LW Gene Haplotypes into the Cause and Prevention of Myopia. Genes (Basel) 2022; 13:genes13060942. [PMID: 35741704 PMCID: PMC9222437 DOI: 10.3390/genes13060942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 05/18/2022] [Accepted: 05/24/2022] [Indexed: 02/01/2023] Open
Abstract
Nearsightedness (myopia) is a global health problem of staggering proportions that has driven the hunt for environmental and genetic risk factors in hopes of gaining insight into the underlying mechanism and providing new avenues of intervention. Myopia is the dominant risk factor for leading causes of blindness, including myopic maculopathy and retinal detachment. The fundamental defect in myopia—an excessively elongated eyeball—causes blurry distance vision that is correctable with lenses or surgery, but the risk of blindness remains. Haplotypes of the long-wavelength and middle-wavelength cone opsin genes (OPN1LW and OPN1MW, respectively) that exhibit profound exon-3 skipping during pre-messenger RNA splicing are associated with high myopia. Cone photoreceptors expressing these haplotypes are nearly devoid of photopigment. Conversely, cones in the same retina that express non-skipping haplotypes are relatively full of photopigment. We hypothesized that abnormal contrast signals arising from adjacent cones differing in photopigment content stimulate axial elongation, and spectacles that reduce contrast may significantly slow myopia progression. We tested for an association between spherical equivalent refraction and OPN1LW haplotype in males of European ancestry as determined by long-distance PCR and Sanger sequencing and identified OPN1LW exon 3 haplotypes that increase the risk of common myopia. We also evaluated the effects of contrast-reducing spectacles lenses on myopia progression in children. The work presented here provides new insight into the cause and prevention of myopia progression.
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Affiliation(s)
- Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA; (J.S.R.); (J.A.K.); (J.N.)
- Correspondence:
| | | | - Jessica S. Rowlan
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA; (J.S.R.); (J.A.K.); (J.N.)
| | - James A. Kuchenbecker
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA; (J.S.R.); (J.A.K.); (J.N.)
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, WA 98109, USA; (J.S.R.); (J.A.K.); (J.N.)
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11
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Neitz M, Neitz J. Intermixing the OPN1LW and OPN1MW Genes Disrupts the Exonic Splicing Code Causing an Array of Vision Disorders. Genes (Basel) 2021; 12:genes12081180. [PMID: 34440353 PMCID: PMC8391646 DOI: 10.3390/genes12081180] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/27/2021] [Accepted: 07/29/2021] [Indexed: 02/07/2023] Open
Abstract
Light absorption by photopigment molecules expressed in the photoreceptors in the retina is the first step in seeing. Two types of photoreceptors in the human retina are responsible for image formation: rods, and cones. Except at very low light levels when rods are active, all vision is based on cones. Cones mediate high acuity vision and color vision. Furthermore, they are critically important in the visual feedback mechanism that regulates refractive development of the eye during childhood. The human retina contains a mosaic of three cone types, short-wavelength (S), long-wavelength (L), and middle-wavelength (M) sensitive; however, the vast majority (~94%) are L and M cones. The OPN1LW and OPN1MW genes, located on the X-chromosome at Xq28, encode the protein component of the light-sensitive photopigments expressed in the L and M cones. Diverse haplotypes of exon 3 of the OPN1LW and OPN1MW genes arose thru unequal recombination mechanisms that have intermixed the genes. A subset of the haplotypes causes exon 3- skipping during pre-messenger RNA splicing and are associated with vision disorders. Here, we review the mechanism by which splicing defects in these genes cause vision disorders.
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12
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Holmquist D, Epstein D, Olsson M, Wissinger B, Kohl S, Hengstler J, Tear-Fahnehjelm K. Visual and ocular findings in a family with X-linked cone dysfunction and protanopia. Ophthalmic Genet 2021; 42:570-576. [PMID: 34287097 DOI: 10.1080/13816810.2021.1938139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Background: Bornholm eye disease (BED) is a rare X-linked cone dysfunction disorder with high myopia, amblyopia, and color vision defects.Materials and methods: Visual and ocular outcomes in a family where two of five siblings had molecularly confirmed BED are reported. Ophthalmological assessments included best-corrected visual acuity (BCVA), color vision test, and optical coherence tomography (OCT). Medical records, electroretinography (ERG), and genetic analyses were re-evaluated.Results: Two male siblings had confirmed BED with myopia and protanopia. The younger brother had high myopia, subnormal BCVA, and ocular fundi that showed tilted discs, crescent shaped peripapillary atrophy, and visible choroidal vessels. OCT confirmed retinal and choroidal atrophy. The older brother was lightly myopic with normal/subnormal BCVA and subtle findings in the fundi. Both brothers had abnormal ERG recordings with a decreased cone response. They also had a structurally intact OPN1LW/OPN1MW gene cluster. The OPN1LW gene was shown to carry a deleterious variant combination in exon 3 known to result in mis-splicing of opsin mRNA and acknowledged as LIAVA amino acid delineation (Leu153-Ile171-Ala174-Val178-Ala180), while the OPN1MW gene exon 3 showed a non-pathogenic variant combination (MVVVA). Another normal-sighted brother carried another wildtype variant combination (LVAIS) in exon 3 of the OPN1LW gene.Conclusions: The two affected brothers demonstrated a large variability in their phenotypes even though the genotypes were identical. They presented a disease-associated haplotype in exon 3 of OPN1LW that has been described as the molecular cause of BED.
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Affiliation(s)
- Dag Holmquist
- Department of Paediatric Ophthalmology, Strabismus, Electrophysiology and Ocular Oncology, St. Erik Eye Hospital, Stockholm, Sweden
| | - David Epstein
- Department of Retinal Diseases, St. Erik Eye Hospital, Stockholm, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Monica Olsson
- Department of Paediatric Ophthalmology, Strabismus, Electrophysiology and Ocular Oncology, St. Erik Eye Hospital, Stockholm, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tübingen, Tübingen, Germany
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tübingen, Tübingen, Germany
| | - Jürg Hengstler
- Department of Retinal Diseases, St. Erik Eye Hospital, Stockholm, Sweden
| | - Kristina Tear-Fahnehjelm
- Department of Paediatric Ophthalmology, Strabismus, Electrophysiology and Ocular Oncology, St. Erik Eye Hospital, Stockholm, Sweden.,Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
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13
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Georgiou M, Fujinami K, Michaelides M. Inherited retinal diseases: Therapeutics, clinical trials and end points-A review. Clin Exp Ophthalmol 2021; 49:270-288. [PMID: 33686777 DOI: 10.1111/ceo.13917] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/22/2021] [Accepted: 03/01/2021] [Indexed: 12/18/2022]
Abstract
Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of disorders characterised by photoreceptor degeneration or dysfunction. These disorders typically present with severe vision loss that can be progressive, with disease onset ranging from congenital to late adulthood. The advances in genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRDs, with the first approved gene therapy and the commencement of multiple clinical trials. The scope of this review is to familiarise clinicians and scientists with the current management and the prospects for novel therapies for: (1) macular dystrophies, (2) cone and cone-rod dystrophies, (3) cone dysfunction syndromes, (4) Leber congenital amaurosis, (5) rod-cone dystrophies, (6) rod dysfunction syndromes and (7) chorioretinal dystrophies. We also briefly summarise the investigated end points for the ongoing trials.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Kaoru Fujinami
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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14
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Ross M, Ofri R, Aizenberg I, Abu-Siam M, Pe'er O, Arad D, Rosov A, Gootwine E, Dvir H, Honig H, Obolensky A, Averbukh E, Banin E, Gantz L. Naturally-occurring myopia and loss of cone function in a sheep model of achromatopsia. Sci Rep 2020; 10:19314. [PMID: 33168939 PMCID: PMC7653946 DOI: 10.1038/s41598-020-76205-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 10/23/2020] [Indexed: 01/01/2023] Open
Abstract
Achromatopsia is an inherited retinal disease characterized by loss of cone photoreceptor function. Day blind CNGA3 mutant Improved Awassi sheep provide a large animal model for achromatopsia. This study measured refractive error and axial length parameters of the eye in this model and evaluated chromatic pupillary light reflex (cPLR) testing as a potential screening test for loss of cone function. Twenty-one CNGA3 mutant, Improved Awassi, 12 control Afec-Assaf and 12 control breed-matched wild-type (WT) Awassi sheep were examined using streak retinoscopy and B-mode ocular ultrasonography. Four CNGA3 mutant and four Afec-Assaf control sheep underwent cPLR testing. Statistical tests showed that day-blind sheep are significantly more myopic than both Afec-Assaf and WT Awassi controls. Day-blind sheep had significantly longer vitreous axial length compared to WT Awassi (1.43 ± 0.13 and 1.23 ± 0.06 cm, respectively, p < 0.0002) and no response to bright red light compared to both controls. Lack of response to bright red light is consistent with cone dysfunction, demonstrating that cPLR can be used to diagnose day blindness in sheep. Day-blind sheep were found to exhibit myopia and increased vitreous chamber depth, providing a naturally occurring large animal model of myopia.
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Affiliation(s)
- Maya Ross
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Ron Ofri
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Itzhak Aizenberg
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | | | - Oren Pe'er
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Dikla Arad
- Koret School of Veterinary Medicine, Hebrew University of Jerusalem, Rehovot, Israel
| | - Alexander Rosov
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Elisha Gootwine
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Hay Dvir
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Hen Honig
- Institute of Animal Science, Agricultural Research Organization, Volcani Center, Rishon LeZion, Israel
| | - Alexey Obolensky
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Edward Averbukh
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Liat Gantz
- Department of Optometry and Vision Science, Hadassah Academic College, 37 Haneviim St., Jerusalem, 9101001, Israel.
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15
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Neitz M, Patterson SS, Neitz J. Photopigment genes, cones, and color update: disrupting the splicing code causes a diverse array of vision disorders. Curr Opin Behav Sci 2019; 30:60-66. [PMID: 32195292 DOI: 10.1016/j.cobeha.2019.05.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The human long- and middle-wavelength sensitive cone opsin genes exhibit an extraordinary degree of haplotype diversity that results from recombination mechanisms that have intermixed the genes. As a first step in expression, genes-including the protein coding exons and intervening introns-are transcribed. Next, transcripts are spliced to remove the introns and join the exons to generate a mature message that codes for the protein. Important information necessary for splicing is contained within exons, and is overlaid by the protein code. Intermixing the long- and middle-wavelength sensitive cone opsin genes has disrupted the splicing code, leading to exclusion of some exons from the mature message and is associated with several vision disorders including nearsightedness, cone dystrophy, and color vision deficiencies.
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Affiliation(s)
- Maureen Neitz
- University of Washington, Department of Ophthalmology, Vision Sciences Center, 750 Republican St, Box 358058, Seattle, WA 98109
| | - Sara S Patterson
- University of Washington, Graduate Program in Neuroscience, Vision Science Center, 750 Republican St, Box 358058, Seattle, WA 98109
| | - Jay Neitz
- University of Washington, Department of Ophthalmology, Vision Sciences Center, 750 Republican St, Box 358058, Seattle, WA 98109
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16
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Patterson EJ, Kalitzeos A, Kasilian M, Gardner JC, Neitz J, Hardcastle AJ, Neitz M, Carroll J, Michaelides M. Residual Cone Structure in Patients With X-Linked Cone Opsin Mutations. Invest Ophthalmol Vis Sci 2019; 59:4238-4248. [PMID: 30128495 PMCID: PMC6103386 DOI: 10.1167/iovs.18-24699] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Purpose To assess residual cone structure in subjects with mutations in exon 2, 3, and 4 of the OPN1LW or OPN1MW opsin. Methods Thirteen males had their OPN1LW/OPN1MW opsin genes characterized. The cone mosaic was imaged using both confocal and nonconfocal split-detection adaptive optics scanning light ophthalmoscopy (AOSLO), and retinal thickness was evaluated using optical coherence tomography (OCT). Six subjects completed serial imaging over a maximum period of 18 months and cone density was measured across imaging sessions. Results Ten subjects had an OPN1LW/OPN1MW "interchange" opsin mutation designated as LIAVA or LVAVA, which both introduce exon 3 splicing defects leading to a lack of functional photopigment in cones expressing LIAVA and greatly reduced functional photopigment in cones expressing LVAVA. Despite disrupted cone reflectivity and reduced numerosity, residual inner segments could be visualized. Similar patterns were observed in individuals with an exon 2 insertion, or an exon 4 splice defect, both of which are also expected to produce cones that are devoid of functional opsin protein. OCT revealed variably reduced retinal thickness. A significant inverse relationship was found between the proportion of waveguiding cones and axial length. Conclusions Split-detection imaging revealed that the altered appearance of the cone mosaic in confocal images for subjects with exon 2, 3, and 4 mutations was generally due to disrupted waveguiding, rather than structural loss, making them possible candidates for gene therapy to restore cone function. The relative fraction of waveguiding cones was highly variable across subjects, which appears to influence emmetropization in these subjects.
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Affiliation(s)
- Emily J Patterson
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Angelos Kalitzeos
- University College London Institute of Ophthalmology, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Melissa Kasilian
- University College London Institute of Ophthalmology, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Jessica C Gardner
- University College London Institute of Ophthalmology, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Alison J Hardcastle
- University College London Institute of Ophthalmology, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
| | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.,Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States.,Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Michel Michaelides
- University College London Institute of Ophthalmology, London, United Kingdom.,Moorfields Eye Hospital, London, United Kingdom
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17
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Georgiou M, Kalitzeos A, Patterson EJ, Dubra A, Carroll J, Michaelides M. Adaptive optics imaging of inherited retinal diseases. Br J Ophthalmol 2017; 102:1028-1035. [PMID: 29141905 PMCID: PMC6059037 DOI: 10.1136/bjophthalmol-2017-311328] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Revised: 10/23/2017] [Accepted: 11/04/2017] [Indexed: 12/17/2022]
Abstract
Adaptive optics (AO) ophthalmoscopy allows for non-invasive retinal phenotyping on a microscopic scale, thereby helping to improve our understanding of retinal diseases. An increasing number of natural history studies and ongoing/planned interventional clinical trials exploit AO ophthalmoscopy both for participant selection, stratification and monitoring treatment safety and efficacy. In this review, we briefly discuss the evolution of AO ophthalmoscopy, recent developments and its application to a broad range of inherited retinal diseases, including Stargardt disease, retinitis pigmentosa and achromatopsia. Finally, we describe the impact of this in vivo microscopic imaging on our understanding of disease pathogenesis, clinical trial design and outcome metrics, while recognising the limitation of the small cohorts reported to date.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Emily J Patterson
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Alfredo Dubra
- Department of Ophthalmology, Stanford University, Palo Alto, California, USA
| | - Joseph Carroll
- Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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18
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Patterson EJ, Wilk M, Langlo CS, Kasilian M, Ring M, Hufnagel RB, Dubis AM, Tee JJ, Kalitzeos A, Gardner JC, Ahmed ZM, Sisk RA, Larsen M, Sjoberg S, Connor TB, Dubra A, Neitz J, Hardcastle AJ, Neitz M, Michaelides M, Carroll J. Cone Photoreceptor Structure in Patients With X-Linked Cone Dysfunction and Red-Green Color Vision Deficiency. Invest Ophthalmol Vis Sci 2017; 57:3853-63. [PMID: 27447086 PMCID: PMC4968428 DOI: 10.1167/iovs.16-19608] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Purpose Mutations in the coding sequence of the L and M opsin genes are often associated with X-linked cone dysfunction (such as Bornholm Eye Disease, BED), though the exact color vision phenotype associated with these disorders is variable. We examined individuals with L/M opsin gene mutations to clarify the link between color vision deficiency and cone dysfunction. Methods We recruited 17 males for imaging. The thickness and integrity of the photoreceptor layers were evaluated using spectral-domain optical coherence tomography. Cone density was measured using high-resolution images of the cone mosaic obtained with adaptive optics scanning light ophthalmoscopy. The L/M opsin gene array was characterized in 16 subjects, including at least one subject from each family. Results There were six subjects with the LVAVA haplotype encoded by exon 3, seven with LIAVA, two with the Cys203Arg mutation encoded by exon 4, and two with a novel insertion in exon 2. Foveal cone structure and retinal thickness was disrupted to a variable degree, even among related individuals with the same L/M array. Conclusions Our findings provide a direct link between disruption of the cone mosaic and L/M opsin variants. We hypothesize that, in addition to large phenotypic differences between different L/M opsin variants, the ratio of expression of first versus downstream genes in the L/M array contributes to phenotypic diversity. While the L/M opsin mutations underlie the cone dysfunction in all of the subjects tested, the color vision defect can be caused either by the same mutation or a gene rearrangement at the same locus.
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Affiliation(s)
- Emily J Patterson
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Melissa Wilk
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Christopher S Langlo
- Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Melissa Kasilian
- UCL Institute of Ophthalmology, London, United Kingdom 4Moorfields Eye Hospital, London, United Kingdom
| | - Michael Ring
- UCL Institute of Ophthalmology, London, United Kingdom 4Moorfields Eye Hospital, London, United Kingdom
| | - Robert B Hufnagel
- Department of Pediatrics, Division of Pediatric Ophthalmology, University of Cincinnati and Cincinnati Children's Hospital, Cincinnati, Ohio, United States
| | - Adam M Dubis
- UCL Institute of Ophthalmology, London, United Kingdom 4Moorfields Eye Hospital, London, United Kingdom
| | - James J Tee
- UCL Institute of Ophthalmology, London, United Kingdom 4Moorfields Eye Hospital, London, United Kingdom
| | - Angelos Kalitzeos
- UCL Institute of Ophthalmology, London, United Kingdom 4Moorfields Eye Hospital, London, United Kingdom
| | | | - Zubair M Ahmed
- Department of Otorhinolaryngology Head & Neck Surgery, School of Medicine, University of Maryland, Baltimore, Maryland, United States
| | - Robert A Sisk
- Department of Pediatrics, Division of Pediatric Ophthalmology, University of Cincinnati and Cincinnati Children's Hospital, Cincinnati, Ohio, United States
| | - Michael Larsen
- Department of Ophthalmology, Rigshospitalet and Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stacy Sjoberg
- Great River Eye Clinic, Crosby, Minnesota, United States
| | - Thomas B Connor
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States
| | - Alfredo Dubra
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States 9Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States 10Department of Cell Biology, Neurobiology, & Anatomy, Medical Coll
| | - Jay Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | | | - Maureen Neitz
- Department of Ophthalmology, University of Washington, Seattle, Washington, United States
| | - Michel Michaelides
- UCL Institute of Ophthalmology, London, United Kingdom 4Moorfields Eye Hospital, London, United Kingdom
| | - Joseph Carroll
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, United States 9Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States 10Department of Cell Biology, Neurobiology, & Anatomy, Medical Coll
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19
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Aboshiha J, Dubis AM, Carroll J, Hardcastle AJ, Michaelides M. The cone dysfunction syndromes. Br J Ophthalmol 2016; 100:115-21. [PMID: 25770143 PMCID: PMC4717370 DOI: 10.1136/bjophthalmol-2014-306505] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/09/2015] [Indexed: 11/05/2022]
Abstract
The cone dysfunction syndromes are a heterogeneous group of inherited, predominantly stationary retinal disorders characterised by reduced central vision and varying degrees of colour vision abnormalities, nystagmus and photophobia. This review details the following conditions: complete and incomplete achromatopsia, blue-cone monochromatism, oligocone trichromacy, bradyopsia and Bornholm eye disease. We describe the clinical, psychophysical, electrophysiological and imaging findings that are characteristic to each condition in order to aid their accurate diagnosis, as well as highlight some classically held notions about these diseases that have come to be challenged over the recent years. The latest data regarding the genetic aetiology and pathological changes observed in the cone dysfunction syndromes are discussed, and, where relevant, translational avenues of research, including completed and anticipated interventional clinical trials, for some of the diseases described herein will be presented. Finally, we briefly review the current management of these disorders.
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Affiliation(s)
- Jonathan Aboshiha
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Adam M Dubis
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Joseph Carroll
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Alison J Hardcastle
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
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20
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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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21
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Gardner JC, Liew G, Quan YH, Ermetal B, Ueyama H, Davidson AE, Schwarz N, Kanuga N, Chana R, Maher ER, Webster AR, Holder GE, Robson AG, Cheetham ME, Liebelt J, Ruddle JB, Moore AT, Michaelides M, Hardcastle AJ. Three different cone opsin gene array mutational mechanisms with genotype-phenotype correlation and functional investigation of cone opsin variants. Hum Mutat 2015; 35:1354-62. [PMID: 25168334 PMCID: PMC4285181 DOI: 10.1002/humu.22679] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/18/2014] [Indexed: 11/22/2022]
Abstract
Mutations in the OPN1LW (L-) and OPN1MW (M-)cone opsin genes underlie a spectrum of cone photoreceptor defects from stationary loss of color vision to progressive retinal degeneration. Genotypes of 22 families with a range of cone disorders were grouped into three classes: deletions of the locus control region (LCR); missense mutation (p.Cys203Arg) in an L-/M-hybrid gene; and exon 3 single-nucleotide polymorphism (SNP) interchange haplotypes in an otherwise normal gene array. Moderate-to-high myopia was observed in all mutation categories. Individuals with LCR deletions or p.Cys203Arg mutations were more likely to have nystagmus and poor vision, with disease progression in some p.Cys203Arg patients. Three disease-associated exon 3 SNP haplotypes encoding LIAVA, LVAVA, or MIAVA were identified in our cohort. These patients were less likely to have nystagmus but more likely to show progression, with all patients over the age of 40 years having marked macular abnormalities. Previously, the haplotype LIAVA has been shown to result in exon 3 skipping. Here, we show that haplotypes LVAVA and MIAVA also result in aberrant splicing, with a residual low level of correctly spliced cone opsin. The OPN1LW/OPN1MW:c.532A>G SNP, common to all three disease-associated haplotypes, appears to be principally responsible for this mutational mechanism.
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Zhang Z, Xu Y, Liu J, Wong DWK, Kwoh CK, Saw SM, Wong TY. Automatic diagnosis of pathological myopia from heterogeneous biomedical data. PLoS One 2013; 8:e65736. [PMID: 23799040 PMCID: PMC3683061 DOI: 10.1371/journal.pone.0065736] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 04/26/2013] [Indexed: 11/21/2022] Open
Abstract
Pathological myopia is one of the leading causes of blindness worldwide. The condition is particularly prevalent in Asia. Unlike myopia, pathological myopia is accompanied by degenerative changes in the retina, which if left untreated can lead to irrecoverable vision loss. The accurate diagnosis of pathological myopia will enable timely intervention and facilitate better disease management to slow down the progression of the disease. Current methods of assessment typically consider only one type of data, such as that from retinal imaging. However, different kinds of data, including that of genetic, demographic and clinical information, may contain different and independent information, which can provide different perspectives on the visually observable, genetic or environmental mechanisms for the disease. The combination of these potentially complementary pieces of information can enhance the understanding of the disease, providing a holistic appreciation of the multiple risks factors as well as improving the detection outcomes. In this study, we propose a computer-aided diagnosis framework for Pathological Myopia diagnosis through Biomedical and Image Informatics(PM-BMII). Through the use of multiple kernel learning (MKL) methods, PM-BMII intelligently fuses heterogeneous biomedical information to improve the accuracy of disease diagnosis. Data from 2,258 subjects of a population-based study, in which demographic and clinical information, retinal fundus imaging data and genotyping data were collected, are used to evaluate the proposed framework. The experimental results show that PM-BMII achieves an AUC of 0.888, outperforming the detection results from the use of demographic and clinical information 0.607 (increase , ), genotyping data 0.774 (increase , ) or imaging data 0.852 (increase , ) alone. The accuracy of the results obtained demonstrates the feasibility of using heterogeneous data for improved disease diagnosis through our proposed PM-BMII framework.
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Affiliation(s)
- Zhuo Zhang
- Institute for Infocomm Research, Agency for Science, Technology and Research, Singapore, Singapore.
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McClements M, Davies WIL, Michaelides M, Young T, Neitz M, MacLaren RE, Moore AT, Hunt DM. Variations in opsin coding sequences cause x-linked cone dysfunction syndrome with myopia and dichromacy. Invest Ophthalmol Vis Sci 2013; 54:1361-9. [PMID: 23322568 DOI: 10.1167/iovs.12-11156] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine the role of variant L opsin haplotypes in seven families with Bornholm Eye Disease (BED), a cone dysfunction syndrome with dichromacy and myopia. METHODS Analysis of the opsin genes within the L/M opsin array at Xq28 included cloning and sequencing of an exon 3-5 gene fragment, long range PCR to establish gene order, and quantitative PCR to establish gene copy number. In vitro expression of normal and variant opsins was performed to examine cellular trafficking and spectral sensitivity of pigments. RESULTS All except one of the BED families possessed L opsin genes that contained a rare exon 3 haplotype. The exception was a family with the deleterious Cys203Arg substitution. Two rare exon 3 haplotypes were found and, where determined, these variant opsin genes were in the first position in the array. In vitro expression in transfected cultured neuronal cells showed that the variant opsins formed functional pigments, which trafficked to the cell membranes. The variant opsins were, however, less stable than wild type. CONCLUSIONS It is concluded that the variant L opsin haplotypes underlie BED. The reduction in the amount of variant opsin produced in vitro compared with wild type indicates a possible disease mechanism. Alternatively, the recently identified defective splicing of exon 3 of the variant opsin transcript may be involved. Both mechanisms explain the presence of dichromacy and cone dystrophy. Abnormal pigment may also underlie the myopia that is invariably present in BED subjects.
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Affiliation(s)
- Michelle McClements
- University College London Institute of Ophthalmology, London, United Kingdom
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Hawthorne FA, Young TL. Genetic contributions to myopic refractive error: Insights from human studies and supporting evidence from animal models. Exp Eye Res 2013; 114:141-9. [PMID: 23379998 DOI: 10.1016/j.exer.2012.12.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 12/13/2012] [Accepted: 12/14/2012] [Indexed: 12/28/2022]
Abstract
Genetic studies of both population-based and recruited affected patient cohorts have identified a number of genomic regions and candidate genes that may contribute to myopic development. Scientists have developed animal models of myopia, as collection of affected tissues from patents is impractical. Recent advances in whole exome sequencing technology show promise for further elucidation of disease causing variants as in the recent identification of rare variants within ZNF644 segregating with pathological myopia. We present a review of the current research trends and findings on genetic contributions to myopic refraction including candidate loci for myopic development and their genomic convergence with expression studies of animal models inducing myopic development.
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25
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McClements M, Davies WIL, Michaelides M, Carroll J, Rha J, Mollon JD, Neitz M, MacLaren RE, Moore AT, Hunt DM. X-linked cone dystrophy and colour vision deficiency arising from a missense mutation in a hybrid L/M cone opsin gene. Vision Res 2013; 80:41-50. [PMID: 23337435 DOI: 10.1016/j.visres.2012.12.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Revised: 12/20/2012] [Accepted: 12/22/2012] [Indexed: 11/17/2022]
Abstract
In this report, we describe a male subject who presents with a complex phenotype of myopia associated with cone dysfunction and a protan vision deficiency. Retinal imaging demonstrates extensive cone disruption, including the presence of non-waveguiding cones, an overall thinning of the retina, and an irregular mottled appearance of the hyper-reflective band associated with the inner segment ellipsoid portion of the photoreceptor. Mutation screening revealed a novel p.Glu41Lys missense mutation in a hybrid L/M opsin gene. Spectral analysis shows that the mutant opsin fails to form a pigment in vitro and fails to be trafficked to the cell membrane in transfected Neuro2a cells. Extensive sequence and quantitative PCR analysis identifies this mutant gene as the only gene present in the affected subject's L/M opsin gene array, yet the presence of protanopia indicates that the mutant opsin must retain some activity in vivo. To account for this apparent contradiction, we propose that a limited amount of functional pigment is formed within the normal cellular environment of the intact photoreceptor, and that this requires the presence of chaperone proteins that promote stability and normal folding of the mutant protein.
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26
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Carroll J, Dubra A, Gardner JC, Mizrahi-Meissonnier L, Cooper RF, Dubis AM, Nordgren R, Genead M, Connor TB, Stepien KE, Sharon D, Hunt DM, Banin E, Hardcastle AJ, Moore AT, Williams DR, Fishman G, Neitz J, Neitz M, Michaelides M. The effect of cone opsin mutations on retinal structure and the integrity of the photoreceptor mosaic. Invest Ophthalmol Vis Sci 2012; 53:8006-15. [PMID: 23139274 DOI: 10.1167/iovs.12-11087] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate retinal structure and photoreceptor mosaic integrity in subjects with OPN1LW and OPN1MW mutations. METHODS Eleven subjects were recruited, eight of whom have been previously described. Cone and rod density was measured using images of the photoreceptor mosaic obtained from an adaptive optics scanning light ophthalmoscope (AOSLO). Total retinal thickness, inner retinal thickness, and outer nuclear layer plus Henle fiber layer (ONL+HFL) thickness were measured using cross-sectional spectral-domain optical coherence tomography (SD-OCT) images. Molecular genetic analyses were performed to characterize the OPN1LW/OPN1MW gene array. RESULTS While disruptions in retinal lamination and cone mosaic structure were observed in all subjects, genotype-specific differences were also observed. For example, subjects with "L/M interchange" mutations resulting from intermixing of ancestral OPN1LW and OPN1MW genes had significant residual cone structure in the parafovea (∼25% of normal), despite widespread retinal disruption that included a large foveal lesion and thinning of the parafoveal inner retina. These subjects also reported a later-onset, progressive loss of visual function. In contrast, subjects with the C203R missense mutation presented with congenital blue cone monochromacy, with retinal lamination defects being restricted to the ONL+HFL and the degree of residual cone structure (8% of normal) being consistent with that expected for the S-cone submosaic. CONCLUSIONS The photoreceptor phenotype associated with OPN1LW and OPN1MW mutations is highly variable. These findings have implications for the potential restoration of visual function in subjects with opsin mutations. Our study highlights the importance of high-resolution phenotyping to characterize cellular structure in inherited retinal disease; such information will be critical for selecting patients most likely to respond to therapeutic intervention and for establishing a baseline for evaluating treatment efficacy.
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Affiliation(s)
- Joseph Carroll
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Flitcroft DI. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye Res 2012; 31:622-60. [PMID: 22772022 DOI: 10.1016/j.preteyeres.2012.06.004] [Citation(s) in RCA: 441] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2011] [Revised: 06/10/2012] [Accepted: 06/21/2012] [Indexed: 02/09/2023]
Abstract
Myopia is the commonest ocular abnormality but as a research topic remains at the margins of mainstream ophthalmology. The concept that most myopes fall into the category of 'physiological myopia' undoubtedly contributes to this position. Yet detailed analysis of epidemiological data linking myopia with a range of ocular pathologies from glaucoma to retinal detachment demonstrates statistically significant disease association in the 0 to -6 D range of 'physiological myopia'. The calculated risks from myopia are comparable to those between hypertension, smoking and cardiovascular disease. In the case of myopic maculopathy and retinal detachment the risks are an order of magnitude greater. This finding highlights the potential benefits of interventions that can limit or prevent myopia progression. Our understanding of the regulatory processes that guide an eye to emmetropia and, conversely how the failure of such mechanisms can lead to refractive errors, is certainly incomplete but has grown enormously in the last few decades. Animal studies, observational clinical studies and more recently randomized clinical trials have demonstrated that the retinal image can influence the eye's growth. To date human intervention trials in myopia progression using optical means have had limited success but have been designed on the basis of simple hypotheses regarding the amount of defocus at the fovea. Recent animal studies, backed by observational clinical studies, have revealed that the mechanisms of optically guided eye growth are influenced by the retinal image across a wide area of the retina and not solely the fovea. Such results necessitate a fundamental shift in how refractive errors are defined. In the context of understanding eye growth a single sphero-cylindrical definition of foveal refraction is insufficient. Instead refractive error must be considered across the curved surface of the retina. This carries the consequence that local retinal image defocus can only be determined once the 3D structure of the viewed scene, off axis performance of the eye and eye shape has been accurately defined. This, in turn, introduces an under-appreciated level of complexity and interaction between the environment, ocular optics and eye shape that needs to be considered when planning and interpreting the results of clinical trials on myopia prevention.
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Affiliation(s)
- D I Flitcroft
- Children's University Hospital, Temple Street, Dublin, Ireland.
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Kitakawa T, Hayashi T, Tsuzuranuki S, Kubo A, Tsuneoka H. Color vision in an elderly patient with protanopic genotype and successfully treated unilateral age-related macular degeneration. Int Ophthalmol 2011; 31:471-5. [PMID: 22076412 DOI: 10.1007/s10792-011-9479-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Accepted: 03/08/2011] [Indexed: 11/29/2022]
Abstract
We investigated differences in color discrimination between the fellow eye and the affected eye successfully treated for unilateral age-related macular degeneration (AMD) in a 69-year-old male patient with protanopia. His best-corrected visual acuity (BCVA) was 1.2 in the right eye (RE) and 0.2 in the left eye (LE). Fundus and angiographic findings showed classic choroidal neovascularization (CNV) secondary to AMD in the LE. BCVA of the LE improved to 0.4, and CNV resolved by 15 months after initiating combined anti-vascular endothelial growth factor and photodynamic therapies. After CNV closure, the Farnsworth dichotomous was performed, showing confusion patterns of the protan axis in either eye. The Farnsworth-Munsell 100-hue test showed a total error score of 520 in the LE, much higher than the score of 348 in the RE. Complete genotypes of the long-wavelength-sensitive (L-) cone and middle-wavelength-sensitive (M-) cone opsin genes were determined by polymerase chain reaction, revealing that the patient had a single 5' L-M 3' hybrid gene (encoding an M-cone opsin), with this genotype responsible for protanopia (the L-cone opsin gene was non-functional), instead of the L-cone and M-cone opsin gene arrays. Poorer color vision discrimination in the LE than the RE remained present despite closure of CNV. The presence and type of congenital color vision defect can be confirmed using molecular genetic testing even if complications of acquired retinal diseases such as AMD are identified.
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Affiliation(s)
- Takaaki Kitakawa
- Department of Ophthalmology, The Jikei University School of Medicine, 3-25-8, Nishi-shimbashi, Minato-ku, Tokyo, 105-8461, Japan
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Abstract
The refractive errors, myopia and hyperopia, are optical defects of the visual system that can cause blurred vision. Uncorrected refractive errors are the most common causes of visual impairment worldwide. It is estimated that 2.5 billion people will be affected by myopia alone within the next decade. Experimental, epidemiological and clinical research has shown that refractive development is influenced by both environmental and genetic factors. Animal models have showed that eye growth and refractive maturation during infancy are tightly regulated by visually guided mechanisms. Observational data in human populations provide compelling evidence that environmental influences and individual behavioral factors play crucial roles in myopia susceptibility. Nevertheless, the majority of the variance of refractive error within populations is thought to be because of hereditary factors. Genetic linkage studies have mapped two dozen loci, while association studies have implicated more than 25 different genes in refractive variation. Many of these genes are involved in common biological pathways known to mediate extracellular matrix (ECM) composition and regulate connective tissue remodeling. Other associated genomic regions suggest novel mechanisms in the etiology of human myopia, such as mitochondrial-mediated cell death or photoreceptor-mediated visual signal transmission. Taken together, observational and experimental studies have revealed the complex nature of human refractive variation, which likely involves variants in several genes and functional pathways. Multiway interactions between genes and/or environmental factors may also be important in determining individual risks of myopia, and may help explain the complex pattern of refractive error in human populations.
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Affiliation(s)
- R Wojciechowski
- Statistical Genetics Section, Inherited Disease Branch, National Human Genome Research Institute/NIH, 333 Cassell Drive, Baltimore, MD 21224, USA.
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30
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Abstract
PURPOSE OF REVIEW Myopia, or nearsightedness, is the most common human eye disorder in the world and is a significant global public health concern. Along with cataract, macular degeneration, infectious disease, and vitamin A deficiency, myopia is one of the most important causes of visual impairment worldwide. Severe or high-grade myopia is a leading cause of blindness because of its associated ocular comorbidities of retinal detachment, macular choroidal degeneration, premature cataract, and glaucoma. Ample epidemiologic and molecular genetic studies support heritability of the nonsyndromic forms of this condition. RECENT FINDINGS Multiple myopia genetic loci have been identified, establishing this entity as a common complex disorder and underscoring the suitability for gene inquiry studies. Animal model research, primarily using form-deprivation techniques, implicates multiple altered regulation of biological substances in the ocular wall layers, which provides important information for prioritizing human candidate gene studies. Recent epidemiologic work supports a greater role for outdoor activity in relieving myopia progression rather than the previous touted young-age near-work activity model. SUMMARY The identification of myopia susceptibility genes will not only provide insight into the molecular basis of this significant eye disorder, but will also identify pathways involved in eye growth and development. This effort may lead to effective therapies to treat or potentially prevent this common eye condition.
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31
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Li YJ, Guggenheim JA, Bulusu A, Metlapally R, Abbott D, Malecaze F, Calvas P, Rosenberg T, Paget S, Creer RC, Kirov G, Owen MJ, Zhao B, White T, Mackey DA, Young TL. An international collaborative family-based whole-genome linkage scan for high-grade myopia. Invest Ophthalmol Vis Sci 2009; 50:3116-27. [PMID: 19324860 DOI: 10.1167/iovs.08-2781] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE Several nonsyndromic high-grade myopia loci have been mapped primarily by microsatellite markers and a limited number of pedigrees. In this study, whole-genome linkage scans were performed for high-grade myopia, using single nucleotide polymorphisms (SNPs) in 254 families from five independent sites. METHODS Genomic DNA samples from 1411 subjects were genotyped (Linkage Panel IVb; Illumina, San Diego, CA). Linkage analyses were performed on 1201 samples from 10 Asian, 12 African-American, and 221 Caucasian families, screening for 5744 SNPs after quality-control exclusions. Two disease states defined by sphere (SPH) and spherical equivalence (SE; sphere+cylinder/2) were analyzed. Parametric and nonparametric two-point and multipoint linkage analyses were performed using the FASTLINK, HOMOG, and MERLIN programs. Multiple stratified datasets were examined, including overall, center-specific, and race-specific. Linkage regions were declared suggestive if they had a peak LOD score >or= 1.5. RESULTS The MYP1, MYP3, MYP6, MYP11, MYP12, and MYP14 loci were replicated. The novel region q34.11 on chromosome 9 (max NPL= 2.07 at rs913275) was identified. Chromosome 12, region q21.2-24.12 (36.59 cM, MYP3 locus) showed significant linkage (peak HLOD = 3.48) at rs337663 in the overall dataset by SPH and was detected by the Duke, Asian, and Caucasian subsets as well. Potential shared interval was race dependent-a 9.4-cM region (rs163016-rs1520724) driven by the Asian subset and a 13.43-cM region (rs163016-rs1520724) driven by the Caucasian subset. CONCLUSIONS The present study is the largest linkage scan to date for familial high-grade myopia. The outcomes will facilitate the identification of genes implicated in myopic refractive error development and ocular growth.
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Affiliation(s)
- Yi-Ju Li
- Center for Human Genetics, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Wojciechowski R, Stambolian D, Ciner E, Ibay G, Holmes TN, Bailey-Wilson JE. Genomewide linkage scans for ocular refraction and meta-analysis of four populations in the Myopia Family Study. Invest Ophthalmol Vis Sci 2009; 50:2024-32. [PMID: 19151385 DOI: 10.1167/iovs.08-2848] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Genomewide linkage scans were performed in Caucasian (CAUC) and Old Order Amish (OOA) families to identify genomic regions containing genes responsible for refractive error control. We also performed a meta-analysis by combining these results with our previous linkage results from Ashkenazi Jewish (ASHK) and African American (AFRAM) families. METHODS Two hundred seventy-one CAUC and 411 OOA participants (36 and 61 families, respectively) were recruited to participate in the Myopia Family Study. Recruitment criteria were designed to enrich the sample for multiplex myopic families. Genomewide, model-free, multipoint linkage analyses were performed separately for each population by using >370 microsatellite markers. Empirical significance levels were determined via gene-dropping simulations. A meta-analysis was performed by combining linkage results from the CAUC, OOA, AFRAM, and ASHK samples, and results were compared to previously reported loci for myopia and refraction. RESULTS Suggestive evidence of linkage was found at 12q24 (LOD = 4.583, P = 0.00037) and 4q21 (LOD = 2.72, P = 0.0028) in the CAUC sample and at 5qter (LOD = 3.271, P = 0.0014) in the OOA. Meta-analysis linkage results were largely driven by population-specific signals from ASHK and AFRAM families. The meta-analysis showed suggestive evidence of linkage to 4q21-22 (meta-P = 0.00214) adjacent to the previously reported MYP9 and MYP11 loci. CONCLUSIONS The results showed suggestive evidence of linkage of ocular refraction to 12q24 and 4q21 in CAUC and to 5qter in OOA families. The meta-analysis supports the view that several genes play a role in refractive development across populations. In MFS families, four broad genomic regions (on 1p, 4q, 7p, and 12q) most likely contain genes that influence ocular refraction.
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Affiliation(s)
- Robert Wojciechowski
- Inherited Disease Research Branch, National Human Genome Research Institute, Baltimore, Maryland 21231, USA.
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33
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Abstract
Myopia, or nearsightedness, is the most common human eye disorder in the world, and is a significant global public health concern. Along with cataract, macular degeneration, infectious disease, and vitamin A deficiency, myopia is one of the most important causes of visual impairment worldwide. Severe or high-grade myopia is a leading cause of blindness because of its associated ocular morbidities of retinal detachment, macular choroidal degeneration, premature cataract, and glaucoma. Ample evidence documents the heritability of the non-syndromic forms of this condition, especially for high-grade myopia, commonly referred to as myopic spherical refractive power of 5 to 6 diopters or higher. Multiple high-grade myopia genetic loci have been identified, and confirmatory studies identifying high-grade and moderate myopia loci have also occurred. In general, myopia susceptibility genes are unknown with few association studies performed, and without confirmation in other research laboratories or testing of separate patient cohorts.
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Affiliation(s)
- Terri L Young
- Department of Ophthalmology and Pediatrics, The Duke Eye Center and the Center for Human Genetics, Duke University Medical Center, Durham, North Carolina 27710, USA.
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34
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Metlapally R, Michaelides M, Bulusu A, Li YJ, Schwartz M, Rosenberg T, Hunt DM, Moore AT, Züchner S, Rickman CB, Young TL. Evaluation of the X-linked high-grade myopia locus (MYP1) with cone dysfunction and color vision deficiencies. Invest Ophthalmol Vis Sci 2008; 50:1552-8. [PMID: 19098318 DOI: 10.1167/iovs.08-2455] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE X-linked high myopia with mild cone dysfunction and color vision defects has been mapped to chromosome Xq28 (MYP1 locus). CXorf2/TEX28 is a nested, intercalated gene within the red-green opsin cone pigment gene tandem array on Xq28. The authors investigated whether TEX28 gene alterations were associated with the Xq28-linked myopia phenotype. Genomic DNA from five pedigrees (with high myopia and either protanopia or deuteranopia) that mapped to Xq28 were screened for TEX28 copy number variations (CNVs) and sequence variants. METHODS To examine for CNVs, ultra-high resolution array-comparative genomic hybridization (array-CGH) assays were performed comparing the subject genomic DNA with control samples (two pairs from two pedigrees). Opsin or TEX28 gene-targeted quantitative real-time gene expression assays (comparative CT method) were performed to validate the array-CGH findings. All exons of TEX28, including intron/exon boundaries, were amplified and sequenced using standard techniques. RESULTS Array-CGH findings revealed predicted duplications in affected patient samples. Although only three copies of TEX28 were previously reported within the opsin array, quantitative real-time analysis of the TEX28 targeted assay of affected male or carrier female individuals in these pedigrees revealed either fewer (one) or more (four or five) copies than did related and control unaffected individuals. Sequence analysis of TEX28 did not reveal any variants associated with the disease status. CONCLUSIONS CNVs have been proposed to play a role in disease inheritance and susceptibility as they affect gene dosage. TEX28 gene CNVs appear to be associated with the MYP1 X-linked myopia phenotypes.
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Zhu G, Hewitt AW, Ruddle JB, Kearns LS, Brown SA, Mackinnon JR, Chen CY, Hammond CJ, Craig JE, Montgomery GW, Martin NG, Mackey DA. Genetic dissection of myopia: evidence for linkage of ocular axial length to chromosome 5q. Ophthalmology 2007; 115:1053-1057.e2. [PMID: 17964656 DOI: 10.1016/j.ophtha.2007.08.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Revised: 08/07/2007] [Accepted: 08/09/2007] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To estimate heritability and locate quantitative trait loci influencing axial length. DESIGN Classic twin study of monozygotic and dizygotic twins reared together. PARTICIPANTS Eight hundred ninety-three individuals from 460 families were recruited through the Twin Eye Study in Tasmania and the Brisbane Adolescent Twin Study (BATS) and had ocular axial length measured. METHODS Structural equation modeling on the entire sample was used to estimate genetic and environmental components of variation in axial length. Analysis of existing microsatellite marker genomewide linkage scan data was performed on 318 individuals from 142 BATS families. MAIN OUTCOME MEASURE Ocular axial length. RESULTS The heritability estimate for axial length, adjusted for age and sex, in the full sample was 0.81. The highest multipoint logarithm of the odds (LOD) score observed was 3.40 (genomewide P = 0.0004), on chromosome 5q (at 98 centimorgans [cM]). Additional regions with suggestive multipoint LOD scores were also identified on chromosome 6 (LOD scores, 2.13 at 76 cM and 2.05 at 83 cM), chromosome 10 (LOD score, 2.03 at 131 cM), and chromosome 14 (LOD score, 2.84 at 97 cM). CONCLUSION Axial length, a major endophenotype for refractive error, is highly heritable and is likely to be influenced by one or more genes on the long arm of chromosome 5.
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Affiliation(s)
- Gu Zhu
- Genetic Epidemiology Unit, Queensland Institute of Medical Research, Brisbane, Australia.
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36
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Zhang Q, Li S, Xiao X, Jia X, Guo X. Confirmation of a genetic locus for X-linked recessive high myopia outside MYP1. J Hum Genet 2007; 52:469-472. [PMID: 17351708 DOI: 10.1007/s10038-007-0130-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 02/09/2007] [Indexed: 10/23/2022]
Abstract
High myopia is a severe ocular condition affecting approximately 100 million people throughout the world. It is a common cause of blindness, and several studies have suggested it is transmitted through Mendelian traits. High myopia is clinically and genetically heterogeneous, with eight loci assigned. Most loci have not been confirmed by additional studies, and genes responsible for high myopia have not been identified. We recently studied a Chinese family with X-linked high myopia and mapped the high myopia locus to Xq25-q27.2. This linked region overlapped with that of MYP13 but was outside MYP1.
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Affiliation(s)
- Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, 54 Xianlie Road, Guangzhou, 510060, People's Republic of China.
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, 54 Xianlie Road, Guangzhou, 510060, People's Republic of China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, 54 Xianlie Road, Guangzhou, 510060, People's Republic of China
| | - Xiaoyun Jia
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, 54 Xianlie Road, Guangzhou, 510060, People's Republic of China
| | - Xiangming Guo
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, 54 Xianlie Road, Guangzhou, 510060, People's Republic of China.
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Hayashi T, Kubo A, Takeuchi T, Gekka T, Goto-Omoto S, Kitahara K. Novel form of a single X-linked visual pigment gene in a unique dichromatic color-vision defect. Vis Neurosci 2006; 23:411-7. [PMID: 16961974 DOI: 10.1017/s0952523806233029] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2005] [Accepted: 11/06/2005] [Indexed: 11/07/2022]
Abstract
In normal trichromats, the long- (L) and middle-wavelength-sensitive (M) pigment genes are arranged in a head-to-tandem array on the X chromosome. Two amino acids at positions 277 and 285, encoded by exon 5 of the L and M genes, respectively, are essential for the spectral difference between L and M pigments whose spectral peaks are at approximately 560 and 530 nm. Intragenic or intergenic unequal crossing-over commonly occurs between the highly homologous L and M genes, resulting in red-green color vision deficiencies. The dichromacy is usually associated with a single L gene for deuteranopia or a single 5' L-M 3' hybrid gene with M-gene exon 5 for protanopia. We clinically diagnosed a total of 88 male dichromats using a Nagel model I anomaloscope, which included one unclassified subject in addition to 31 protanopes and 56 deuteranopes. The objective of this study was to characterize the phenotype of the subject and to determine the genotype of his X-linked pigment genes. The subject accepted not only any red-green mixture but also an extended yellow-scale range at each matching point (i.e. 20 to 32 scale units at the green primary and 3.5 to 6 scale units at the red primary). The slopes of regression lines were in the range of -0.34 to -0.23, while the mean slopes for the protanopes and deuteranopes were -0.38 and -0.01, respectively. Spectral sensitivity tests showed that the subject's curve was shifted between the protanope and deuteranope curves. Molecular analysis revealed a novel form of a single pigment gene with a unique arrangement of exon 5 (Y277 from the L gene and A285 from the M gene). The predicted lambdamax (541 to 546 nm) of the unique pigment was closer to the M than to the L pigment. Our outcome suggests that intragenic unequal crossing-over may have occurred between amino acid positions 279 and 283.
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Affiliation(s)
- Takaaki Hayashi
- Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan.
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Zhang Q, Guo X, Xiao X, Jia X, Li S, Hejtmancik JF. Novel locus for X linked recessive high myopia maps to Xq23-q25 but outside MYP1. J Med Genet 2006; 43:e20. [PMID: 16648373 PMCID: PMC2564525 DOI: 10.1136/jmg.2005.037853] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND High myopia is a common genetic variation in most cases, affecting 1-2% of people, and is the fourth most common disorder causing blindness worldwide. Six autosomal dominant loci and one X-linked recessive locus have been reported, but no genes responsible for high myopia have been identified. OBJECTIVE To report a Chinese family in which six males presented with high myopia consistent with an X linked recessive trait. RESULTS Affected individuals shared three common features: high myopia, reduced visual acuity, and fundal changes of high myopia. Protan and deutan were observed in the family, but they did not co-segregate with the high myopia phenotype. X-chromosome-wide linkage analysis mapped the high myopia locus to a 25 cM (14.9 Mb) region on Xq23-q25 between DXS1210 and DXS8057, with maximum two point lod scores at theta = 0 of 2.75 and 2.29 for DXS1001 and DXS8059, respectively. CONCLUSIONS This new myopia locus is outside the linked region of the first high myopia locus (MYP1). Refinement of the linkage region with additional families and screening candidate genes for mutation may lead to the identification of the defect gene.
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Xiao X, Jia X, Guo X, Li S, Yang Z, Zhang Q. CSNB1 in Chinese families associated with novel mutations in NYX. J Hum Genet 2006; 51:634-40. [PMID: 16670814 DOI: 10.1007/s10038-006-0406-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Accepted: 03/20/2006] [Indexed: 10/24/2022]
Abstract
X-linked congenital stationary night blindness (CSNB) and NYX mutation have not been reported in Chinese. Here, two Chinese families with the complete form of CSNB (CSNB1) are presented. Linkage analysis of one family mapped the disease to Xp11-Xq13 where NYX is located. Sequence analysis of NYX identified two novel mutations, c.281G>C and c.302T>C, which would result in missense changes of p.Arg94Pro and p.Ile101Thr in the encoded protein. These two mutations were not found in 96 controls. The c.281G>C mutation cosegregated with nyctalopia and myopia. Our results expand the mutation spectrum of NYX and enrich the clinical information related to NYX mutation. The importance of associated myopia with NYX mutations is discussed.
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Affiliation(s)
- Xueshan Xiao
- Key Laboratory of Ophthalmology of the Ministry of Education and Zhongshan Ophthalmic Center, Sun Yat-sen University, 54 Xianlie Road, Guangzhou, 510060, PR China
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Wojciechowski R, Moy C, Ciner E, Ibay G, Reider L, Bailey-Wilson JE, Stambolian D. Genomewide scan in Ashkenazi Jewish families demonstrates evidence of linkage of ocular refraction to a QTL on chromosome 1p36. Hum Genet 2006; 119:389-99. [PMID: 16501916 PMCID: PMC3123998 DOI: 10.1007/s00439-006-0153-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2005] [Accepted: 01/29/2006] [Indexed: 11/24/2022]
Abstract
UNLABELLED The development of refractive error is mediated by both environmental and genetic factors. We performed regression-based quantitative trait locus (QTL) linkage analysis on Ashkenazi Jewish families to identify regions in the genome responsible for ocular refraction. We measured refractive error on individuals in 49 multi-generational American families of Ashkenazi Jewish descent. The average family size was 11.1 individuals and was composed of 2.7 generations. Recruitment criteria specified that each family contain at least two myopic members. The mean spherical equivalent refractive error in the sample was -3.46D (SD=3.29) and 87% of individuals were myopic. Microsatellite genotyping with 387 markers was performed on 411 individuals. We performed multipoint regression-based linkage analysis for ocular refraction and a log transformation of the trait using the statistical package Merlin-Regress. Empirical genomewide significance levels were estimated through gene-dropping simulations by generating random genotypes at each of the 387 markers in 200 replicates of our pedigrees. Maximum LOD scores of 9.5 for ocular refraction and 8.7 for log-transformed refraction (LTR) were observed at 49.1 cM on chromosome 1p36 between markers D1S552 and D1S1622. The empirical genomewide significance levels were P=0.065 for ocular refraction and P<0.005 for LTR, providing strong evidence for linkage of refraction to this locus. The inter-marker region containing the peak spans 11 Mb and contains approximately 189 genes. CONCLUSION We found genomewide significant evidence for linkage of refractive error to a novel QTL on chromosome 1p36 in an Ashkenazi Jewish population.
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Affiliation(s)
- Robert Wojciechowski
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
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Michaelides M, Johnson S, Bradshaw K, Holder GE, Simunovic MP, Mollon JD, Moore AT, Hunt DM. X-Linked Cone Dysfunction Syndrome with Myopia and Protanopia. Ophthalmology 2005; 112:1448-54. [PMID: 15953640 DOI: 10.1016/j.ophtha.2005.02.021] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2004] [Accepted: 02/21/2005] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To perform a detailed clinical, psychophysical, and molecular assessment of members of 4 families with an unusual X-linked cone dysfunction syndrome associated with myopia. PARTICIPANTS Affected and unaffected members of 4 British nonconsanguineous families. METHODS Subjects underwent both detailed clinical examination and psychophysical testing. After informed consent was obtained, blood samples were taken for DNA extraction, and molecular genetic analysis was performed. The strategy for molecular analysis was to amplify the coding regions of the long and middle wavelength-sensitive cone opsin genes and the upstream locus control region by polymerase chain reaction and to examine these fragments for mutations by sequencing of DNA. RESULTS The phenotype was almost identical in all 4 families, consisting of moderate to high myopia, astigmatism, moderately reduced acuity, and normal fundi. Electroretinography showed abnormal cone but normal rod responses. Psychophysical testing showed a selective impairment of long cones in combination with well-preserved middle cone and short cone function. There was no evidence to suggest that the phenotype was progressive. Molecular analysis of the X-linked opsin gene array in the 4 families indicated that affected males have inherited the same X-chromosome from their mother. In 2 families, a long/middle hybrid gene was detected. In a third family, the commonly described deleterious Cys203Arg amino acid substitution was identified in both the long and middle opsin genes. In the fourth family, the only abnormality was absence of a middle opsin exon 2; the cause of the protanopia in this family is uncertain. CONCLUSIONS The X-linked cone dysfunction syndrome associated with myopia and dichromacy described here has many similarities to Bornholm eye disease, a condition previously mapped to Xq28. Except for the Cys203Arg substitution in one family, no alterations in the opsin gene array were identified that could underlie the cone dysfunction. It is therefore possible that the cone dysfunction may have a genetic origin different from that of the dichromacy.
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Affiliation(s)
- Michel Michaelides
- Institute of Ophthalmology, University College London, London, United Kingdom
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