1
|
Kirkby J, Halford S, Shanks M, Moore A, Gait A, Jenkins L, Clouston P, Patel CK, Downes SM. A Carrier Female Manifesting an Unusual X-Linked Retinoschisis Phenotype Associated with the Pathogenic Variant c.266delA, p.(Tyr89LeufsTer37) in RS1, and Skewed X-Inactivation. Genes (Basel) 2023; 14:1193. [PMID: 37372373 DOI: 10.3390/genes14061193] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/24/2023] [Accepted: 05/25/2023] [Indexed: 06/29/2023] Open
Abstract
X-linked retinoschisis (XLRS) is the most common juvenile macular degeneration in males. Unlike most other X-linked retinal dystrophies, carrier heterozygous females are very rarely reported to show clinical features of the disease. Herein, we describe unusual retinal features in a 2-year-old female infant with family history and genetic testing consistent with XLRS.
Collapse
Affiliation(s)
- Jennifer Kirkby
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Stephanie Halford
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| | - Morag Shanks
- Oxford Medical Genetics Laboratory, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Anthony Moore
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA 94158, USA
| | - Anthony Gait
- Rare & Inherited Disease Genomic Laboratory, Great Ormond Street for Children NHS Foundation Trust, London WC1N 3JN, UK
| | - Lucy Jenkins
- Rare & Inherited Disease Genomic Laboratory, Great Ormond Street for Children NHS Foundation Trust, London WC1N 3JN, UK
| | - Penny Clouston
- Oxford Medical Genetics Laboratory, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Chetan K Patel
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Susan M Downes
- Oxford Eye Hospital, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neuroscience, University of Oxford, Level 6 John Radcliffe Hospital, Headley Way, Oxford OX3 9DU, UK
| |
Collapse
|
2
|
Li H, Li J, Huang Y, Sui R. Clinical and genetic study of a pseudo-dominant retinoschisis pedigree: the first female patient reported in Chinese population. Ophthalmic Genet 2022; 43:433-437. [PMID: 35189768 DOI: 10.1080/13816810.2022.2042702] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND The inheritance pattern of genetically confirmed hereditary juvenile retinoschisis reported so far is X-linked recessive with limited number of female cases. We identified a female patient with retinoschisis, and this study reports the clinical features as well as the underlying genetic defect of this family. MATERIALS AND METHODS Detailed family history and pedigree analysis were performed. All affected subjects underwent detailed ophthalmic examinations, including best corrected visual acuity (BCVA), dilated fundoscopy, optical coherent tomography (OCT) and fundus autofluorescence (FAF). DNA sample of the proband was sequenced by next-generation sequencing (NGS). Sanger sequencing was performed for validation and segregation. RESULTS Three affected subjects including one female and two males were confirmed in this consanguineous family. The BCVA ranged from 20/50 to hand motion. Foveoschisis, hyperopia, subcapsular cataracts, vitreous opacity, retinal pigmentation, and macular atrophy were present in all three patients, with variable severity. Nystagmus, esotropia, and retinal vessels transposition were noted in the female patient. Retinal detachment occurred in the female patient and her affected brother. A small deletion in RS1 gene c.97delT (p.W33Gfs*93) (NM_000330.3) was found, which was co-segregated in the pedigree. CONCLUSIONS Consanguineous family having XLRS female patient could manifest as pseudo-dominant inheritance. Significant intrafamilial phenotypic variation was revealed.
Collapse
Affiliation(s)
- Huajin Li
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Jing Li
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Yanfeng Huang
- Department of Ophthalmology, The First Affiliated Hospital of Fujian Medical University, Fuzhou, China
| | - Ruifang Sui
- Department of Ophthalmology, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China
| |
Collapse
|
3
|
Vijaysarathy C, Babu Sardar Pasha SP, Sieving PA. Of men and mice: Human X-linked retinoschisis and fidelity in mouse modeling. Prog Retin Eye Res 2021; 87:100999. [PMID: 34390869 DOI: 10.1016/j.preteyeres.2021.100999] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 08/02/2021] [Accepted: 08/06/2021] [Indexed: 02/07/2023]
Abstract
X-linked Retinoschisis (XLRS) is an early-onset transretinal dystrophy, often with a prominent macular component, that affects males and generally spares heterozygous females because of X-linked recessive inheritance. It results from loss-of-function RS1 gene mutations on the X-chromosome. XLRS causes bilateral reduced acuities from young age, and on clinical exam and by ocular coherence tomography (OCT) the neurosensory retina shows foveo-macular cystic schisis cavities in the outer plexiform (OPL) and inner nuclear layers (INL). XLRS manifests between infancy and school-age with variable phenotypic presentation and without reliable genotype-phenotype correlations. INL disorganization disrupts synaptic signal transmission from photoreceptors to ON-bipolar cells, and this reduces the electroretinogram (ERG) bipolar b-wave disproportionately to photoreceptor a-wave changes. RS1 gene expression is localized mainly to photoreceptors and INL bipolar neurons, and RS1 protein is thought to play a critical cell adhesion role during normal retinal development and later for maintenance of retinal structure. Several independent XLRS mouse models with mutant RS1 were created that recapitulate features of human XLRS disease, with OPL-INL schisis cavities, early onset and variable phenotype across mutant models, and reduced ERG b-wave to a-wave amplitude ratio. The faithful phenotype of the XLRS mouse has assisted in delineating the disease pathophysiology. Delivery to XLRS mouse retina of an AAV8-RS1 construct under control of the RS1 promoter restores the retinal structure and synaptic function (with increase of b-wave amplitude). It also ameliorates the schisis-induced inflammatory microglia phenotype toward a state of immune quiescence. The results imply that XLRS gene therapy could yield therapeutic benefit to preserve morphological and functional retina particularly when intervention is conducted at earlier ages before retinal degeneration becomes irreversible. A phase I/IIa single-center, open-label, three-dose-escalation clinical trial reported a suitable safety and tolerability profile of intravitreally administered AAV8-RS1 gene replacement therapy for XLRS participants. Dose-related ocular inflammation occurred after dosing, but this resolved with topical and oral corticosteroids. Systemic antibodies against AAV8 increased in dose-dependent fashion, but no antibodies were observed against the RS1 protein. Retinal cavities closed transiently in one participant. Technological innovations in methods of gene delivery and strategies to further reduce immune responses are expected to enhance the therapeutic efficacy of the vector and ultimate success of a gene therapy approach.
Collapse
Affiliation(s)
| | | | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, 20892, USA; Department of Ophthalmology, University of California Davis, 95817, USA.
| |
Collapse
|
4
|
Wang W, Liu J, Yang M, Qiu R, Li Y, Bian S, Hao B, Lei B. Intravitreal Injection of an Exosome-Associated Adeno-Associated Viral Vector Enhances Retinoschisin 1 Gene Transduction in the Mouse Retina. Hum Gene Ther 2021; 32:707-716. [PMID: 33832349 DOI: 10.1089/hum.2020.328] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
To investigate whether exosome-associated adeno-associated virus (AAV) retinoschisin 1 (RS1) vector improved the transduction efficiency of RS1 in the mouse retina. pAAV2-RS1-ZsGreen plasmid was constructed by homologous recombination. Exosome-associated AAV vectors containing human RS1 gene (exosome-associated AAV [exo-AAV]2-RS1-ZsGreen) were isolated from producer cells' supernatant, and confirmed by transmission electron microscopy, nanoparticle tracking analysis, and western blotting. In vitro, HEK-293T cells were transduced with AAV2-RS1-ZsGreen and exo-AAV2-RS1-ZsGreen. In vivo, 1 μL of AAV2-RS1-ZsGreen or 1 μL exo-AAV2-RS1-ZsGreen (2 × 108 genome copies/μL) was injected intravitreally into the C57BL/6J mouse eyes. Phosphate buffer saline was injected as controls. The mRNA and the protein expression in the retina were detected. Exo-AAV2-RS1-ZsGreen possessed lipid bilayers, a saucer-like structures and an average of 120 nm particle size. The expression of RS1 and ZsGreen in exo-AAV2-RS1-ZsGreen group were 7.6 times and 5.7 times that of AAV2-RS1-ZsGreen group in HEK-293T cells, respectively. Furthermore, RS1 protein expression increased by 11.8 times in HEK-293T cells. Intravitreal injection of exo-AAV significantly increased the transduction efficiency of RS1 than AAV. Exo-AAV may be a powerful gene delivery system for gene therapy of X-link retinoschisis as well as other inherited retina degenerations.
Collapse
Affiliation(s)
- Weiping Wang
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Jingyang Liu
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Mingzhu Yang
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ruiqi Qiu
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Ya Li
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Shasha Bian
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Bingtao Hao
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| | - Bo Lei
- Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Henan Provincial People's Hospital, Zhengzhou, China
| |
Collapse
|
5
|
Önen M, Zor K, Küçük E, Yıldırım G. X-Linked Retinoschisis in Females in a Consanguineous Family: A Rare Entity. Turk J Ophthalmol 2020; 50:252-254. [PMID: 32854471 PMCID: PMC7469900 DOI: 10.4274/tjo.galenos.2020.42815] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
X-linked juvenile retinoschisis (XLRS) is a disease considered characteristic for males. In this study we report a consanguineous family in which 3 daughters were diagnosed with XLRS. Typical signs of XLRS were detected in 2 girls, aged 4 and 15. Fundoscopic examination of the father and the oldest daughter (age 17) revealed bilateral atrophic macula and retinal thinning. Although rare and considered characteristic for males, XLRS can be seen in females in Middle-East countries that have a high rate of consanguineous marriage. It can be overlooked by ophthalmologists and these patients may be misdiagnosed.
Collapse
Affiliation(s)
- Mehmet Önen
- Ankara City Hospital, Clinic of Ophthalmology, Ankara, Turkey
| | - Kürşat Zor
- Niğde Ömer Halisdemir University Faculty of Medicine, Department of Ophthalmology, Niğde, Turkey
| | - Erkut Küçük
- Niğde Ömer Halisdemir University Faculty of Medicine, Department of Ophthalmology, Niğde, Turkey
| | - Gamze Yıldırım
- Niğde Ömer Halisdemir Training and Research Hospital, Clinic of Ophthalmology, Niğde, Turkey
| |
Collapse
|
6
|
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: 68] [Impact Index Per Article: 17.0] [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.
Collapse
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.
| |
Collapse
|
7
|
Liu Y, Kinoshita J, Ivanova E, Sun D, Li H, Liao T, Cao J, Bell BA, Wang JM, Tang Y, Brydges S, Peachey NS, Sagdullaev BT, Romano C. Mouse models of X-linked juvenile retinoschisis have an early onset phenotype, the severity of which varies with genotype. Hum Mol Genet 2020; 28:3072-3090. [PMID: 31174210 DOI: 10.1093/hmg/ddz122] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 05/04/2019] [Accepted: 06/03/2019] [Indexed: 12/17/2022] Open
Abstract
X-linked juvenile retinoschisis (XLRS) is an early-onset inherited condition that affects primarily males and is characterized by cystic lesions of the inner retina, decreased visual acuity and contrast sensitivity and a selective reduction of the electroretinogram (ERG) b-wave. Although XLRS is genetically heterogeneous, all mouse models developed to date involve engineered or spontaneous null mutations. In the present study, we have studied three new Rs1 mutant mouse models: (1) a knockout with inserted lacZ reporter gene; (2) a C59S point mutant substitution and (3) an R141C point mutant substitution. Mice were studied from postnatal day (P15) to 28 weeks by spectral domain optical coherence tomography and ERG. Retinas of P21-22 mice were examined using biochemistry, single cell electrophysiology of retinal ganglion cells (RGCs) and by immunohistochemistry. Each model developed intraretinal schisis and reductions in the ERG that were greater for the b-wave than the a-wave. The phenotype of the C59S mutant appeared less severe than the other mutants by ERG at adult ages. RGC electrophysiology demonstrated elevated activity in the absence of a visual stimulus and reduced signal-to-noise ratios in response to light stimuli. Immunohistochemical analysis documented early abnormalities in all cells of the outer retina. Together, these results provide significant insight into the early events of XLRS pathophysiology, from phenotype differences between disease-causing variants to common mechanistic events that may play critical roles in disease presentation and progression.
Collapse
Affiliation(s)
- Yang Liu
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Junzo Kinoshita
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Elena Ivanova
- Burke Neurological Institute at Weill Cornell Medicine, White Plains, NY 10605, USA
| | - Duo Sun
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Hong Li
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Tara Liao
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Jingtai Cao
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | - Brent A Bell
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Jacob M Wang
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Yajun Tang
- Regeneron Pharmaceuticals, Tarrytown, NY 10591, USA
| | | | - Neal S Peachey
- Cole Eye Institute, Cleveland Clinic, Cleveland, OH 44195, USA.,Louis Stokes Cleveland VA Medical Center, Cleveland, OH 44106, USA.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Botir T Sagdullaev
- Burke Neurological Institute at Weill Cornell Medicine, White Plains, NY 10605, USA
| | | |
Collapse
|
8
|
Khan AO, El-Ghrably IA. Overlapping retinal phenotypes in a consanguineous family harboring mutations in CRB1 and RS1. Ophthalmic Genet 2019; 40:17-21. [DOI: 10.1080/13816810.2018.1561906] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Arif O. Khan
- Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western University, Cleveland, OH, USA
| | | |
Collapse
|
9
|
Staffieri SE, Rose L, Chang A, De Roach JN, McLaren TL, Mackey DA, Hewitt AW, Lamey TM. Clinical and molecular characterization of females affected by X-linked retinoschisis. Clin Exp Ophthalmol 2015; 43:643-7. [DOI: 10.1111/ceo.12541] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 04/03/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Sandra E Staffieri
- Centre for Eye Research Australia; University of Melbourne; Department of Ophthalmology; Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
| | - Loreto Rose
- Macquarie University; Sydney New South Wales Australia
| | - Andrew Chang
- Save Sight Institute; University of Sydney; Sydney New South Wales Australia
| | - John N De Roach
- Australian Inherited Retinal Disease Register & DNA Bank; Department of Medical Technology and Physics; Sir Charles Gairdner Hospital; Perth Western Australia Australia
| | - Terri L McLaren
- Australian Inherited Retinal Disease Register & DNA Bank; Department of Medical Technology and Physics; Sir Charles Gairdner Hospital; Perth Western Australia Australia
| | - David A Mackey
- Centre for Eye Research Australia; University of Melbourne; Department of Ophthalmology; Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
- Lions Eye Institute; Centre for Ophthalmology and Visual Science; University of Western Australia; Perth Western Australia Australia
- School of Medicine; Menzies Institute for Medical Research; University of Tasmania; Hobart Tasmania Australia
| | - Alex W Hewitt
- Centre for Eye Research Australia; University of Melbourne; Department of Ophthalmology; Royal Victorian Eye and Ear Hospital; Melbourne Victoria Australia
- Lions Eye Institute; Centre for Ophthalmology and Visual Science; University of Western Australia; Perth Western Australia Australia
- School of Medicine; Menzies Institute for Medical Research; University of Tasmania; Hobart Tasmania Australia
| | - Tina M Lamey
- Australian Inherited Retinal Disease Register & DNA Bank; Department of Medical Technology and Physics; Sir Charles Gairdner Hospital; Perth Western Australia Australia
| |
Collapse
|
10
|
|
11
|
Molday RS, Kellner U, Weber BHF. X-linked juvenile retinoschisis: clinical diagnosis, genetic analysis, and molecular mechanisms. Prog Retin Eye Res 2012; 31:195-212. [PMID: 22245536 PMCID: PMC3334421 DOI: 10.1016/j.preteyeres.2011.12.002] [Citation(s) in RCA: 220] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Revised: 12/16/2011] [Accepted: 12/19/2011] [Indexed: 01/07/2023]
Abstract
X-linked juvenile retinoschisis (XLRS, MIM 312700) is a common early onset macular degeneration in males characterized by mild to severe loss in visual acuity, splitting of retinal layers, and a reduction in the b-wave of the electroretinogram (ERG). The RS1 gene (MIM 300839) associated with the disease encodes retinoschisin, a 224 amino acid protein containing a discoidin domain as the major structural unit, an N-terminal cleavable signal sequence, and regions responsible for subunit oligomerization. Retinoschisin is secreted from retinal cells as a disulphide-linked homo-octameric complex which binds to the surface of photoreceptors and bipolar cells to help maintain the integrity of the retina. Over 190 disease-causing mutations in the RS1 gene are known with most mutations occurring as non-synonymous changes in the discoidin domain. Cell expression studies have shown that disease-associated missense mutations in the discoidin domain cause severe protein misfolding and retention in the endoplasmic reticulum, mutations in the signal sequence result in aberrant protein synthesis, and mutations in regions flanking the discoidin domain cause defective disulphide-linked subunit assembly, all of which produce a non-functional protein. Knockout mice deficient in retinoschisin have been generated and shown to display most of the characteristic features found in XLRS patients. Recombinant adeno-associated virus (rAAV) mediated delivery of the normal RS1 gene to the retina of young knockout mice result in long-term retinoschisin expression and rescue of retinal structure and function providing a 'proof of concept' that gene therapy may be an effective treatment for XLRS.
Collapse
Affiliation(s)
- Robert S Molday
- Department of Biochemistry and Molecular Biology, Centre of Macular Research, University of British Columbia, 2350 Health Sciences Mall, Vancouver, B.C. V6T 1Z3, Canada.
| | | | | |
Collapse
|
12
|
|