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Gocuk SA, Jolly JK, Edwards TL, Ayton LN. Female carriers of X-linked inherited retinal diseases - Genetics, diagnosis, and potential therapies. Prog Retin Eye Res 2023; 96:101190. [PMID: 37406879 DOI: 10.1016/j.preteyeres.2023.101190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 06/13/2023] [Accepted: 06/14/2023] [Indexed: 07/07/2023]
Abstract
Inherited retinal diseases (IRDs) are a group of heterogeneous conditions that cause progressive vision loss, typically due to monogenic mutations. Female carriers of X-linked IRDs have a single copy of the disease-causing gene, and therefore, may exhibit variable clinical signs that vary from near normal retina to severe disease and vision loss. The relationships between individual genetic mutations and disease severity in X-linked carriers requires further study. This review summarises the current literature surrounding the spectrum of disease seen in female carriers of choroideremia and X-linked retinitis pigmentosa. Various classification systems are contrasted to accurately grade retinal disease. Furthermore, genetic mechanisms at the early embryonic stage are explored to potentially explain the variability of disease seen in female carriers. Future research in this area will provide insight into the association between genotype and retinal phenotypes of female carriers, which will guide in the management of these patients. This review acknowledges the importance of identifying which patients may be at high risk of developing severe symptoms, and therefore should be considered for emerging treatments, such as retinal gene therapy.
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Affiliation(s)
- Sena A Gocuk
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - Jasleen K Jolly
- Vision and Eye Research Institute, Anglia Ruskin University, Cambridge, UK
| | - Thomas L Edwards
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia
| | - Lauren N Ayton
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Victoria, Australia; Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Victoria, Australia; Ophthalmology, Department of Surgery, The University of Melbourne, Melbourne, Victoria, Australia.
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Parmann R, Greenstein VC, Tsang SH, Sparrow JR. Choroideremia Carriers: Dark-Adapted Perimetry and Retinal Structures. Invest Ophthalmol Vis Sci 2022; 63:4. [PMID: 35816046 PMCID: PMC9284471 DOI: 10.1167/iovs.63.8.4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose In choroideremia (CHM) carriers, scotopic sensitivity was assessed by dark adapted chromatic perimetry (DACP) and outer retinal structure was evaluated by multimodal imaging. Methods Nine carriers (18 eyes) and 13 healthy controls (13 eyes) underwent DACP testing with cyan and red stimuli. Analysis addressed peripapillary (4 test locations closest to the optic disc), macular (52 locations), and peripheral (60 locations outside the macula) regions. Responses were considered to be rod-mediated when cyan relative to red sensitivity was >5 dB. Fundus imaging included spectral domain optical coherence tomography (SD-OCT), short-wavelength (SW-AF), near-infrared (NIR-AF), ultrawide-field (200 degrees) pseudocolor fundus imaging, and quantitative (qAF) fundus autofluorescence. Results Detection of the cyan stimulus was rod mediated in essentially all test locations (99.7%). In the macular and peripheral areas, DACP sensitivity values were not significantly different from healthy eyes. In the peripapillary area, sensitivities were significantly decreased (P < 0.05). SD-OCT imaging ranged from hyper-reflective lesions and discontinuities of the outer retinal bands to hypertransmission of signal. SW-AF and NIR-AF images presented with peripapillary atrophy in seven patients (14 eyes). Mosaicism was detectable in SW-AF images in seven patients and in NIR-AF images in five patients. Frank hypo-autofluorescence was visible in eight patients with distinct chorioretinopathy in seven patients. The qAF values were below the 95% confidence interval (CI) of healthy age-matched individuals in 12 eyes. Conclusions Rod mediated scotopic sensitivity was comparable to that in control eyes in macular and peripheral areas but was decreased in the peripapillary area where changes in retinal structure were also most severe.
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Affiliation(s)
- Rait Parmann
- Departments of Ophthalmology, Columbia University, New York, NY, United States
| | | | - Stephen H Tsang
- Departments of Ophthalmology, Columbia University, New York, NY, United States.,Departments of Pathology and Cell Biology, Columbia University, New York, NY, United States
| | - Janet R Sparrow
- Departments of Ophthalmology, Columbia University, New York, NY, United States.,Departments of Pathology and Cell Biology, Columbia University, New York, NY, United States
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De Silva SR, Arno G, Robson AG, Fakin A, Pontikos N, Mohamed MD, Bird AC, Moore AT, Michaelides M, Webster AR, Mahroo OA. The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies. Prog Retin Eye Res 2020; 82:100898. [PMID: 32860923 DOI: 10.1016/j.preteyeres.2020.100898] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/07/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research.
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Affiliation(s)
- Samantha R De Silva
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Ana Fakin
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Moin D Mohamed
- Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Alan C Bird
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK; Section of Ophthalmology, King's College London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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Abstract
PURPOSE To examine the features of the tapetal-like reflex (TLR) in female carriers of RPGR-associated retinopathy by means of adaptive optics scanning light ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography. METHODS Nine molecularly confirmed RPGR carriers and three healthy controls underwent ocular examination and the following retinal imaging modalities: color photography, near-infrared reflectance, fundus autofluorescence, spectral domain optical coherence tomography, and AOSLO. After identifying TLR areas across all imaging modalities, normalized local contrast of outer retinal bands on spectral domain optical coherence tomography was calculated and AOSLO-acquired photoreceptor mosaic analysis was performed. RESULTS Seven carriers had TLR areas, which colocalized with increased rod photoreceptor reflectivity on confocal AOSLO and reduced cone photoreceptor densities. Parafoveal TLR areas also exhibited reduced local contrast (i.e., increased reflectivity) of the outer retinal bands on spectral domain optical coherence tomography (inner segment ellipsoid zone and outer segment interdigitation zone). Healthy controls did not show TLR. CONCLUSION The cellular resolution provided by AOSLO affords the characterization of the photoreceptor mosaic in RPGR carriers with a TLR. Features revealed include reduced cone density, increased cone inner segment diameter, and increased rod outer segment reflectivity.
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Paavo M, Carvalho JRL, Lee W, Sengillo JD, Tsang SH, Sparrow JR. Patterns and Intensities of Near-Infrared and Short-Wavelength Fundus Autofluorescence in Choroideremia Probands and Carriers. Invest Ophthalmol Vis Sci 2020; 60:3752-3761. [PMID: 31499530 PMCID: PMC6735265 DOI: 10.1167/iovs.19-27366] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Purpose To ascertain cellular constituents within islands of preserved retina in choroideremia (CHM) by multimodal imaging. Methods CHM probands (16) and female carriers (9) of CHM were studied. Near-infrared autofluorescence (NIR-AF; 787-nm excitation; emission, >830 nm), short-wavelength autofluorescence (SW-AF; 488-nm excitation, 500- to 680-nm emission), and spectral-domain optical coherence tomography (SD-OCT) images were acquired with a confocal scanning laser ophthalmoscope. SW-AF intensities were measured by quantitative fundus autofluorescence (qAF), and NIR-AF intensity profiles were analyzed. Retinal thicknesses and visual acuity were measured. Results In 19 of 31 eyes of affected males, islands of preserved NIR-AF signal were also visible as fluorescence signal in SW-AF images. Notable in 12 eyes were areas of speckled SW-AF that was hypoautofluorescent in the NIR-AF image. Islands of preserved NIR-AF and SW-AF signal were often associated with the presence of visible but thinned outer nuclear layer and discontinuous interdigitation zone, ellipsoid zone, and external limiting membrane. NIR-AF profiles revealed that even in areas of preserved retina, the NIR-AF signal from retinal pigment epithelium (RPE) melanin is greatly reduced. qAF was reduced overall. The fundus of carriers was characterized by a mosaicism in which patches of reduced NIR-AF colocalized with reduced SW-AF. Conclusions In CHM-affected males, the presence of RPE was indicated by an NIR-AF signal and the absence of hypertransmission of OCT signal into the choroid. RPE preservation was associated with better visual acuity. In carriers, patches of reduced SW-AF colocalized with decreased NIR-AF and qAF was severely reduced.
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Affiliation(s)
- Maarjaliis Paavo
- Department of Ophthalmology Columbia University Medical Center, New York, New York, United States.,Department of Ophthalmology, Helsinki University Hospital, Helsinki, Finland
| | - Jose R L Carvalho
- Department of Ophthalmology Columbia University Medical Center, New York, New York, United States.,Department of Ophthalmology, Empresa Brasileira de Servicos Hospitalares, Hospital das Clinicas de Pernambuco, Federal University of Pernambuco, Recife, Brazil.,Department of Ophthalmology, Federal University of São Paulo, São Paulo, Brazil
| | - Winston Lee
- Department of Ophthalmology Columbia University Medical Center, New York, New York, United States
| | - Jesse D Sengillo
- Department of Ophthalmology Columbia University Medical Center, New York, New York, United States.,Department of Internal Medicine, Reading Hospital of Tower Health, West Reading, Pennsylvania, United States
| | - Stephen H Tsang
- Department of Ophthalmology Columbia University Medical Center, New York, New York, United States.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States
| | - Janet R Sparrow
- Department of Ophthalmology Columbia University Medical Center, New York, New York, United States.,Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York, United States
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Wert KJ, Bakall B, Bassuk AG, Tsang SH, Mahajan VB. Insights into Retinal Development Using Live Imaging in Female Carriers of Choroideremia. Ophthalmic Surg Lasers Imaging Retina 2019; 50:e158-e162. [PMID: 31100169 DOI: 10.3928/23258160-20190503-15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Accepted: 06/04/2018] [Indexed: 11/20/2022]
Abstract
Lineage tracing can provide key insights into the development of tissues, such as the retina. Yet it is not possible to manipulate human cells during embryogenesis. The authors observed a distinct phenotype in female carriers of X-linked disorders, in particular, carriers of choroideremia caused by mutations in CHM, encoding Rab escort protein-1. The authors found that X chromosome inactivation provides a method for retinal lineage tracing in human patients. Live imaging of female carriers displays a developmental pattern that is different within the peripheral retina compared with the posterior retina and provides important insights into the development and migration of retinal cells. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:e158-e162.].
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Suzuki K, Gocho K, Akeo K, Kikuchi S, Kubota D, Katagiri S, Fujinami K, Tsunoda K, Iwata T, Yamaki K, Igarashi T, Nakano T, Takahashi H, Hayashi T, Kameya S. High-Resolution Retinal Imaging Reveals Preserved Cone Photoreceptor Density and Choroidal Thickness in Female Carriers of Choroideremia. Ophthalmic Surg Lasers Imaging Retina 2019; 50:76-85. [PMID: 30768214 DOI: 10.3928/23258160-20190129-03] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Accepted: 11/02/2018] [Indexed: 08/02/2024]
Abstract
BACKGROUND AND OBJECTIVE To characterize the photoreceptors and choroidal morphology of heterozygous female carriers of choroideremia who typically do not have any visual defects but can have severe funduscopic changes. PATIENTS AND METHODS This was a clinical case series study. Detailed ophthalmic examinations were performed on six female carriers from four families with choroideremia. The subfoveal choroidal thickness (SFCT) was determined by spectral-domain optical coherence tomography (SD-OCT) and the cone photoreceptor density by adaptive optics (AO) retinal imaging. SFCT and cone densities of the carriers were compared to that of normal eyes of healthy subjects. RESULTS The mean age of the carriers was 42.5 years. Fundus photographs showed diffuse, patchy depigmentation; however, the SFCT was within the normal limits. AO retinal imaging revealed preserved cone densities at temporal eccentricities from 2 to 8 angular degrees. CONCLUSIONS The findings indicate that despite the presence of distinctive depigmentation of the retinal pigment epithelium in female carriers of choroideremia, their cone photoreceptor densities and SFCT are well-preserved. These observations may account for the good visual acuity and lack of an awareness of visual disturbances. [Ophthalmic Surg Lasers Imaging Retina. 2019;50:76-85.].
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Murro V, Mucciolo DP, Passerini I, Palchetti S, Sodi A, Virgili G, Rizzo S. Retinal dystrophy and subretinal drusenoid deposits in female choroideremia carriers. Graefes Arch Clin Exp Ophthalmol 2017; 255:2099-2111. [DOI: 10.1007/s00417-017-3751-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2017] [Revised: 06/22/2017] [Accepted: 07/10/2017] [Indexed: 11/30/2022] Open
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PHENOTYPING CHOROIDEREMIA AND ITS CARRIER STATE WITH MULTIMODAL IMAGING TECHNIQUES. Retin Cases Brief Rep 2017; 11 Suppl 1:S178-S181. [PMID: 27599108 DOI: 10.1097/icb.0000000000000419] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To describe findings in a patient with choroideremia (CHM) and his mother, an obligate CHM carrier. METHODS Case report. RESULTS A 25-year-old man with nyctalopia and poor peripheral vision since childhood, as well as a family history consistent with an X-linked retinal disorder was diagnosed with CHM. His asymptomatic 50-year-old mother, an obligate carrier, was also examined. Fundus examination of the affected man showed significant atrophy of the choroid and retinal pigment epithelium, whereas the carrier woman showed patchy pigmentary mottling. Imaging of the affected man showed diffuse retinal pigment epithelium atrophy on optical coherence tomography and extensive areas of decreased choriocapillaris flow on optical coherence tomography angiography. By contrast, the carrier woman showed subtle retinal pigment epithelium changes on optical coherence tomography and mild flow alterations on optical coherence tomography angiography. CONCLUSION This case demonstrates the findings seen in CHM, and while CHM carrier women are often asymptomatic, they may exhibit a mosaic pattern of pigmentary change on fundus examination. Optical coherence tomography angiography may show mild choroidal flow abnormalities. This finding serves to further characterize the extent of dysfunction in CHM and its carrier state.
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Fahim AT, Daiger SP. The Role of X-Chromosome Inactivation in Retinal Development and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:325-31. [PMID: 26427428 DOI: 10.1007/978-3-319-17121-0_43] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The expression of X-linked genes is equalized between males and females in mammalian species through X-Chromosome inactivation (XCI). Every cell in a female mammalian embryo randomly chooses one X Chromosome for epigenetic silencing at the 8-16 cell stage, resulting in a Gaussian distribution of XCI ratios with a peak at 50:50. At the tail extremes of this distribution, X-linked recessive mutations can manifest in disease in female carriers if the mutant allele is disproportionately active. The role of XCI skewing, if any, in X-linked retinal disease is still unknown, although many have speculated that such skewing accounts for phenotypic variation in female carriers of X-linked retinitis pigmentosa (XlRP). Some investigators have used clinical findings such as tapetal-like reflex, pigmentary changes, and multifocal ERG parameters to approximate XCI patches in the retina. These studies are limited by small cohorts and the relative inaccessibility of retinal tissue for genetic and epigenetic analysis. Although blood has been used as a proxy for other tissues in determining XCI ratios, blood XCI skews with age out of proportion to other tissues and may not accurately reflect retinal XCI ratios. Future investigations in determining retinal XCI ratios and the contribution of XCI to phenotype could potentially impact prognosis for female carriers of X-linked retinal disease.
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Affiliation(s)
- Abigail T Fahim
- Department of Ophthalmology and Visual Sciences, University of Michigan, Kellogg Eye Center, 1000 Wall Street, 48105, Ann Arbor, MI, USA.
| | - Stephen P Daiger
- School of Public Health, University of Texas Health Science Center, 1200 Herman Pressler Drive, RAS W-522, 77030, Houston, TX, USA.
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Dimopoulos IS, Chan S, MacLaren RE, MacDonald IM. Pathogenic mechanisms and the prospect of gene therapy for choroideremia. Expert Opin Orphan Drugs 2015; 3:787-798. [PMID: 26251765 PMCID: PMC4522943 DOI: 10.1517/21678707.2015.1046434] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Choroideremia is a rare, X-linked disorder recognized by its specific ocular phenotype as a progressive degenerative retinopathy resulting in blindness. New therapeutic approaches, primarily based on genetic mechanisms, have emerged that aim to prevent the progressive vision loss. AREAS COVERED This article will review the research that has progressed incrementally over the past two decades from mapping to gene discovery, uncovering the presumed mechanisms triggering the retinopathy to preclinical testing of potential therapies. EXPERT OPINION While still in an evaluative phase, the introduction of gene replacement as a potential therapy has been greeted with great enthusiasm by patients, advocacy groups and the medical community.
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Affiliation(s)
- Ioannis S Dimopoulos
- University of Alberta, Department of Ophthalmology and Visual Sciences, Edmonton, Alberta, Canada
| | - Stephanie Chan
- University of Alberta, Department of Ophthalmology and Visual Sciences, Edmonton, Alberta, Canada
| | - Robert E MacLaren
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, John Radcliffe Hospital, Oxford, UK
- Moorfields Eye Hospital Foundation Trust, NIHR Ophthalmology Biomedical Research Centre, London, UK
| | - Ian M MacDonald
- University of Alberta, Department of Ophthalmology and Visual Sciences, Edmonton, Alberta, Canada
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Abstract
PURPOSE OF REVIEW To describe the entity of Lyonization in ocular eye diseases, along with its clinical and counseling implications. RECENT FINDINGS Several X-linked ocular diseases such as choroideremia, X-linked retinitis pigmentosa, and X-linked ocular albinism may have signs of Lyonization on ocular examination and diagnostic testing. These findings may aid in the proper diagnosis of ocular disease in both female carriers and their affected male relatives. SUMMARY Manifestations of Lyonization in the eye may help in the diagnosis of X-linked ocular diseases which may lead to accurate diagnosis, appropriate molecular genetic testing and genetic counseling.
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Choroideremia: towards a therapy. Am J Ophthalmol 2013; 156:433-437.e3. [PMID: 23810476 DOI: 10.1016/j.ajo.2013.05.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Revised: 05/06/2013] [Accepted: 05/09/2013] [Indexed: 12/17/2022]
Abstract
PURPOSE To review what progress has been made towards the application of ocular gene therapy to prevent progressive vision loss in patients affected by choroideremia. DESIGN A Perspective based on the collective opinions of researchers and clinicians actively engaged in vision research on choroideremia and a review of current literature. METHODS Researchers from Europe, Canada, Australia, and the United States were convened to the first International Choroideremia Research Symposium held in Sommières, France in September 2011. Attendees shared their collective understanding of the pathophysiology of choroideremia and current trends in the development of treatments, with an emphasis on the potential of gene therapy as an achievable approach. Supplemental perspectives are provided along with an update of progress made since the meeting. RESULTS The complexity of treating a retinal disease such as choroideremia that affects multiple tissue layers has been brought to light. The genetic basis of choroideremia must be thoroughly deciphered and appropriate clinical tests selected to follow disease progression and evaluate the efficiency of treatments. CONCLUSIONS Whereas the time frame for the development of therapies for some retinal dystrophies may be in the years hence, gene therapy trials for choroideremia have started in the United Kingdom and results are pending. These first trials may help resolve the remaining issues associated with the treatment of this disease.
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Syed R, Sundquist SM, Ratnam K, Zayit-Soudry S, Zhang Y, Crawford JB, MacDonald IM, Godara P, Rha J, Carroll J, Roorda A, Stepien KE, Duncan JL. High-resolution images of retinal structure in patients with choroideremia. Invest Ophthalmol Vis Sci 2013; 54:950-61. [PMID: 23299470 DOI: 10.1167/iovs.12-10707] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To study retinal structure in choroideremia patients and carriers using high-resolution imaging techniques. METHODS Subjects from four families (six female carriers and five affected males) with choroideremia (CHM) were characterized with best-corrected visual acuity (BCVA), kinetic and static perimetry, full-field electroretinography, and fundus autofluorescence (FAF). High-resolution macular images were obtained with adaptive optics scanning laser ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography (SD-OCT). Coding regions of the CHM gene were sequenced. RESULTS Molecular analysis of the CHM gene identified a deletion of exons 9 to 15 in family A, a splice site mutation at position 79+1 of exon 1 in family B, deletion of exons 6 to 8 in family C, and a substitution at position 106 causing a premature stop in family D. BCVA ranged from 20/16 to 20/63 in carriers and from 20/25 to 5/63 in affected males. FAF showed abnormalities in all subjects. SD-OCT showed outer retinal layer loss, outer retinal tubulations at the margin of outer retinal loss, and inner retinal microcysts. Patchy cone loss was present in two symptomatic carriers. In two affected males, cone mosaics were disrupted with increased cone spacing near the fovea but more normal cone spacing near the edge of atrophy. CONCLUSIONS High-resolution retinal images in CHM carriers and affected males demonstrated RPE and photoreceptor cell degeneration. As both RPE and photoreceptor cells were affected, these cell types may degenerate simultaneously in CHM. These findings provide insight into the effect of CHM mutations on macular retinal structure, with implications for the development of treatments for CHM. (ClinicalTrials.gov number, NCT00254605.).
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Affiliation(s)
- Reema Syed
- Department of Ophthalmology, University of California, San Francisco, USA
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Coussa RG, Kim J, Traboulsi EI. Choroideremia: effect of age on visual acuity in patients and female carriers. Ophthalmic Genet 2011; 33:66-73. [PMID: 22060191 DOI: 10.3109/13816810.2011.623261] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND/AIMS The extent and time course of vision loss in Choroideremia (CHM) is still unclear. We undertook this study to quantitate the change in visual acuity (VA) over time in order to gain a better understanding of the natural course of this retinal disorder. METHODS Corrected VA of 120 males with CHM and 53 female carriers were collected from 24 studies and/or case reports published between 1981 and 2010, as well as from data on 15 patients examined at the Cole Eye Institute (Cleveland Clinic). Cross-sectional and longitudinal analyses were used to investigate the relationship between VA and age, as well as the progression rate of VA with age, respectively. Age grouping effects were investigated using ANOVA. RESULTS The mean age of affected males was 36.6 ± 17.7 years. The mean logMAR VA was 0.35 ± 0.53. There was a significant 0.0072 decrease in logMAR VA per year (p = 1.22 × 10(-4)). There was a significant difference between VA of patients <50 years of age and those >50 years (0.27 ± 0.39 vs. 0.61 ± 0.81, p = 2.90 × 10(-5)). When we compared the rate of VA loss for patients <50 years vs. those >50 years, we also found a significant difference (0.01 ± 0.04 vs. 0.06 ± 0.08, p = 1.23 × 10(-2)). The average age of female carriers was 36.4 ± 17.7 years, with an average logMAR VA of 0.36 ± 0.6. There was no significant correlation between VA of female carriers and age (p = 0.12) with 46% of female carriers having a VA better than 20/20 at an average age of 33 years compared to 25% of affected males at 30 years. CONCLUSION In affected males with CHM, VA decreases very slowly until subjects reach 50 years of age, at which time the rate and extent of vision loss become significantly higher. Additionally, VA decreases more rapidly as individuals get older. In contradistinction to affected males, VA loss in female carriers is much milder.
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Abstract
Choroideremia (CHM) is an X-linked retinal dystrophy belonging to the family of blinding disorders. It is characterized by progressive degeneration of the choriocapillaris, retinal pigment epithelium and photoreceptors. CHM is caused by mutations in the Rab Escort Protein 1 (REP-1) gene, which encodes a protein involved in vesicular trafficking. This paper gives an overview of the clinical features, visual function, biochemistry, histology, molecular genetics, pathogenesis, diagnosis and treatment of CHM.
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Thobani A, Anastasakis A, Fishman GA. Microperimetry and OCT findings in female carriers of choroideremia. Ophthalmic Genet 2010; 31:235-9. [DOI: 10.3109/13816810.2010.518578] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Abstract
PURPOSE OF REVIEW To introduce the issues specific to the genetic counseling profession for genetic eye diseases. RECENT FINDINGS To discuss current issues in ocular genetic counseling including the use of a focused ophthalmology pedigree, informed consent in the blind population, genetic testing trends and psychosocial issues. SUMMARY Introduce the time-consuming issues to be addressed in genetic counseling for genetic eye disease patients.
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Preising MN, Wegscheider E, Friedburg C, Poloschek CM, Wabbels BK, Lorenz B. Fundus Autofluorescence in Carriers of Choroideremia and Correlation with Electrophysiologic and Psychophysical Data. Ophthalmology 2009; 116:1201-9.e1-2. [DOI: 10.1016/j.ophtha.2009.01.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 12/12/2008] [Accepted: 01/15/2009] [Indexed: 10/20/2022] Open
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MacDonald IM, Sui R, Zein W. Lines of Blaschko and choroideremia. Ophthalmology 2009; 116:1017-8; author reply 1018. [PMID: 19410966 DOI: 10.1016/j.ophtha.2009.01.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Accepted: 01/22/2009] [Indexed: 11/16/2022] Open
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Fishman GA, Vajaranant TS. Author reply. Ophthalmology 2009. [DOI: 10.1016/j.ophtha.2009.01.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Meyer CH, Rodrigues EB, Kroll P. Lines of Blaschko. Ophthalmology 2008; 115:1855. [PMID: 18929175 DOI: 10.1016/j.ophtha.2008.05.019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2008] [Accepted: 05/12/2008] [Indexed: 10/21/2022] Open
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