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Cetin GO, Cetin EN, Akyol T, Ilhan HD, Pekel G. Genotype and phenotype characteristics of X-linked retinoschisis: the first report of a Turkish population. Ophthalmic Genet 2021; 43:318-325. [PMID: 34865595 DOI: 10.1080/13816810.2021.2010772] [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 X-linked retinoschisis is an inherited retinal disease caused by mutations in the RS1 gene; however, a genotype-phenotype correlation regarding the mutation type or location within the RS1 gene and clinical characteristics of the patients has not been established yet. This is the first report documenting the genotypes and ophthalmological findings in a Turkish population with confirmed RS1 mutations. MATERIALS AND METHODS Fifty eyes of 25 male patients were included in the study. RS1 mutation analysis was performed by DNA sequencing. Retrospective analysis of ocular examinations and SD-OCT scans were applied. RESULTS The major mutation was c.422 G > A (p.Arg141His, exon 5) affecting 14 patients (56%) and c.531 T > G was the only non-sense mutation out of 7 pathogenic variants. At presentation; the mean age was 24.6 ± 16.2 (4-72) years, mean visual acuity (VA) was 0.61 ± 0.32 (logMAR, 0.10-1.30). Forty-six (92%) eyes had macular, 16 eyes (32%) had peripheral retinoschisis. None of the eyes had macular scar, whereas 7 eyes (14%) had macular atrophy. The most frequent location of schisis was inner nuclear layer (37.5%). The eyes with disruption of ellipsoid zone (EZ) or external limiting membrane (ELM) had worse VA (for EZ, 0.65 ± 0.25 versus 0.45 ± 0.34, logMAR, 31 versus 17 eyes, p = .013; for ELM, 0.66 ± 0.27 versus 0.45 ± 0.31, logMAR, 30 versus 18 eyes, p = .008). CONCLUSIONS Seven different pathogenic variants in the RS1 gene were identified; with c.422 G > A (p.Arg141His) as the most frequent variant and c.531 T > G as only non-sense mutation. Having EZ or ELM disruption were the significant factors affecting VA.
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Affiliation(s)
- Gokhan Ozan Cetin
- Department of Medical Genetics, Medical School of Pamukkale University, Denizli, Turkey
| | - Ebru Nevin Cetin
- Department of Ophthalmology, Medical School of Pamukkale University, Denizli, Turkey
| | - Tunahan Akyol
- Department of Ophthalmology, Medical School of Pamukkale University, Denizli, Turkey
| | - Hatice Deniz Ilhan
- Department of Ophthalmology, Medical School of Akdeniz University, Antalya, Turkey
| | - Gokhan Pekel
- Department of Ophthalmology, Medical School of Pamukkale University, Denizli, Turkey
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2
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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.
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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.
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3
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Grigg JR, Hooper CY, Fraser CL, Cornish EE, McCluskey PJ, Jamieson RV. Outcome measures in juvenile X-linked retinoschisis: A systematic review. Eye (Lond) 2020; 34:1760-1769. [PMID: 32313171 PMCID: PMC7608480 DOI: 10.1038/s41433-020-0848-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 01/06/2020] [Accepted: 03/01/2020] [Indexed: 01/01/2023] Open
Abstract
X-linked retinoschisis (XLRS) is a leading cause of hereditary juvenile macular degeneration in males resulting in significant vision impairment. Outcome measures to monitor disease progression or therapeutic interventions have evolved with technology. A systematic review was undertaken to evaluate outcome measures for XLRS. Inclusion criteria were all publications examining outcome measures for natural history studies or following an interventional approach for patients with XLRS. Studies which did not present follow-up data were excluded. We searched medical databases including CENTRAL, Ovid Medline, pre-Medline and ahead of Print up to February 2019. Two authors independently assessed the risk of bias. Twelve studies meet the inclusion criteria with four prospective and eight retrospective case series. Five series were natural history observational studies and seven were interventional series using either topical or systemic carbonic anhydrase inhibitors. Visual acuity (VA) declined very slowly in the natural history studies equivalent to 0.22-0.5 letters per year. Five of the six interventional studies showed an improvement in VA and four a reduction in spectral domain optical coherence tomography (SD-OCT) parameters for central macular thickness (CMT). The full-field electroretinogram identified the 30-Hz latency as a further parameter to monitor function. VA was the measure most likely to show a statistically significant outcome. How functionally meaningful this is, requires further evaluation. CMT SD-OCT outcomes are variable depending on cystic changes. More refined measures are required to better correlate structure with function.
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Affiliation(s)
- John R Grigg
- Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine and Health, Save Sight Institute, 8 Macquarie Street, Sydney, NSW, 2001, Australia. .,Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia. .,Sydney Eye Hospital, Macquarie Street, Sydney, NSW, Australia.
| | - Claire Y Hooper
- Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine and Health, Save Sight Institute, 8 Macquarie Street, Sydney, NSW, 2001, Australia.,Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia
| | - Clare L Fraser
- Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine and Health, Save Sight Institute, 8 Macquarie Street, Sydney, NSW, 2001, Australia.,Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia.,Sydney Eye Hospital, Macquarie Street, Sydney, NSW, Australia
| | - Elisa E Cornish
- Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine and Health, Save Sight Institute, 8 Macquarie Street, Sydney, NSW, 2001, Australia.,Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia.,Sydney Eye Hospital, Macquarie Street, Sydney, NSW, Australia
| | - Peter J McCluskey
- Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine and Health, Save Sight Institute, 8 Macquarie Street, Sydney, NSW, 2001, Australia.,Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia.,Sydney Eye Hospital, Macquarie Street, Sydney, NSW, Australia
| | - Robyn V Jamieson
- Discipline of Clinical Ophthalmology and Eye Health, Faculty of Medicine and Health, Save Sight Institute, 8 Macquarie Street, Sydney, NSW, 2001, Australia.,Eye Genetics Research, The Children's Hospital at Westmead, Save Sight Institute, Children's Medical Research Institute, University of Sydney, Sydney, NSW, Australia.,Disciplines of Genetic Medicine and Child and Adolescent Health, Sydney Medical School, University of Sydney, Sydney, NSW, Australia
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4
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Kondo H, Oku K, Katagiri S, Hayashi T, Nakano T, Iwata A, Kuniyoshi K, Kusaka S, Hiyoshi A, Uchio E, Kondo M, Oishi N, Kameya S, Mizota A, Naoi N, Ueno S, Terasaki H, Morimoto T, Iwaki M, Yoshitake K, Iejima D, Fujinami K, Tsunoda K, Shinoda K, Iwata T. Novel mutations in the RS1 gene in Japanese patients with X-linked congenital retinoschisis. Hum Genome Var 2019; 6:3. [PMID: 30652005 PMCID: PMC6325138 DOI: 10.1038/s41439-018-0034-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 11/12/2018] [Accepted: 12/09/2018] [Indexed: 12/04/2022] Open
Abstract
X-linked congenital retinoschisis (XLRS) is an inherited retinal disorder characterized by reduced central vision and schisis of the macula and peripheral retina. XLRS is caused by mutations in the RS1 gene. We have identified 37 different mutations in the RS1 gene, including 12 novel mutations, in 67 Japanese patients from 56 XLRS families. We present clinical features of these patients in relation to the associated mutations.
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Affiliation(s)
- Hiroyuki Kondo
- 1Department of Ophthalmology, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Kazuma Oku
- 1Department of Ophthalmology, University of Occupational and Environmental Health, Kitakyushu, Japan
| | - Satoshi Katagiri
- 2Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Takaaki Hayashi
- 2Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Tadashi Nakano
- 2Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Akiko Iwata
- 3Department of Ophthalmology, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Kazuki Kuniyoshi
- 3Department of Ophthalmology, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Shunji Kusaka
- 3Department of Ophthalmology, Kindai University Faculty of Medicine, Osakasayama, Japan
| | - Atsushi Hiyoshi
- 4Department of Ophthalmology, Fukuoka University, Fukuoka, Japan
| | - Eiichi Uchio
- 4Department of Ophthalmology, Fukuoka University, Fukuoka, Japan
| | - Mineo Kondo
- 5Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Japan
| | - Noriko Oishi
- 6Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
| | - Shuhei Kameya
- 6Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Chiba, Japan
| | - Atsushi Mizota
- 7Department of Ophthalmology, Teikyo University, Tokyo, Japan
| | - Nobuhisa Naoi
- 8Department of Ophthalmology, Miyazaki University, Miyazaki, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nogoya University Graduate School of Medicine, Nagoya, Japan
| | - Hiroko Terasaki
- Department of Ophthalmology, Nogoya University Graduate School of Medicine, Nagoya, Japan
| | - Takeshi Morimoto
- 10Department of Applied Visual Science, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Masayoshi Iwaki
- 11Department of Ophthalmology, Aichi Medical University, Nagakute, Japan
| | - Kazutoshi Yoshitake
- 12Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Daisuke Iejima
- 12Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Kaoru Fujinami
- 13Division of Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Kazushige Tsunoda
- 13Division of Vision Research, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Kei Shinoda
- 14Department of Ophthalmology, Saitama Medical University, Moroyama, Japan
| | - Takeshi Iwata
- 12Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
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5
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Understanding variable disease severity in X-linked retinoschisis: Does RS1 secretory mechanism determine disease severity? PLoS One 2018; 13:e0198086. [PMID: 29851975 PMCID: PMC5978886 DOI: 10.1371/journal.pone.0198086] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 05/14/2018] [Indexed: 11/24/2022] Open
Abstract
X-linked retinoschisis (XLRS) is a retinal degenerative disorder caused by mutations in RS1 gene leading to splitting of retinal layers (schisis) which impairs visual signal processing. Retinoschisin (RS1) is an adhesive protein which is secreted predominantly by the photoreceptors and bipolar cells as a double-octameric complex. In general, XLRS patients show wide clinical heterogeneity, presenting practical challenges in disease management. Though researchers have attempted various approaches to offer an explanation for clinical heterogeneity, the molecular basis has not been understood yet. Therefore, this study aims at establishing a link between the phenotype and genotype based on the molecular mechanism exerted by the mutations. Twenty seven XLRS patients were enrolled, of which seven harboured novel mutations. The mutant constructs were genetically engineered and their secretion profiles were studied by in vitro cell culture experiments. Based on the secretory profile, the patients were categorized as either secreted or non-secreted group. Various clinical parameters such as visual acuity, location of schisis, foveal thickness and ERG parameters were compared between the two groups and control. Although the two groups showed severe disease phenotype in comparison with control, there was no significant difference between the two XLRS groups. However, the secreted group exhibited relatively severe disease indications. On the other hand molecular analysis suggests that most of the RS1 mutations result in intracellular retention of retinoschisin. Hence, clinical parameters of patients with non-secreted profile were analyzed which in turn revealed wide variability even within the group. Altogether, our results indicate that disease severity is not merely dependent on secretory profile of the mutations. Thus, we hypothesize that intricate molecular detail such as the precise localization of mutant protein in the cell as well as its ability to assemble into a functionally active oligomer might largely influence disease severity among XLRS patients.
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6
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Katagiri S, Tanaka S, Yokoi T, Hayashi T, Matsuzaka E, Ueda K, Yoshida-Uemura T, Arakawa A, Nishina S, Kadonosono K, Azuma N. Clinical features of a toddler with bilateral bullous retinoschisis with a novel RS1 mutation. Am J Ophthalmol Case Rep 2016; 5:76-80. [PMID: 29503952 PMCID: PMC5758021 DOI: 10.1016/j.ajoc.2016.12.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 11/30/2016] [Accepted: 12/08/2016] [Indexed: 11/03/2022] Open
Abstract
Purpose To report the clinical and genetic findings of a male toddler who presented bilateral bullous retinoschisis with a novel RS1 mutation. Observations This is an observational case report of a patient referred to our hospital with esotropia. A comprehensive ophthalmic examination was performed with the boy (age, 1 year 4 months) under general anesthesia that included fundus examinations, fluorescein angiography (FA), swept-source optical coherence tomography (SS-OCT), and full-field electroretinography (FF-ERG). Genetic analysis of the coding region in the RS1 gene was performed by Sanger sequencing for the patient and mother. There was a family history of X-linked retinoschisis (XLRS). Fundus examinations and FA showed bullous retinoschisis bilaterally in the inferior retina. The SS-OCT images showed two kinds of schisis in the inner nuclear layer (INL) and more proximally. In general, the inner plexiform layer, ganglion cell layer, and retinal nerve fiber layer are in the proximal INL; however, in this case there was hyperreflective tissue with a rough surface instead of normal retinal layers. In addition, in the schisis cavity between the hyperreflective tissue and separated retina, a number of hyperreflective fiber-like strands arose from the hyperreflective tissue and extended to the schisis cavity. During the follow-up period, the bullous retinoschisis collapsed spontaneously in the right eye. FF-ERG showed a reduced b-wave and relatively preserved a-wave in all components. Genetic analysis showed a novel RS1 mutation (c.185_186insT, p.E62DfsX24 in exon 4) in the patient and mother. Conclusions and importance We report the detailed retinal structure in a genetically identified case of bullous retinoschisis. The notable finding was that the cavity of bullous retinoschisis contained a number of fiber-like strands as observed in the cavity of typical retinoschisis.
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Affiliation(s)
- Satoshi Katagiri
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan.,Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Shin Tanaka
- Department of Ophthalmology, Yokohama City University Medical Center, Yokohama, Japan
| | - Tadashi Yokoi
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Tokyo, Japan
| | - Emiko Matsuzaka
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan
| | - Kazuko Ueda
- Department of Ophthalmology, Yokohama City University Medical Center, Yokohama, Japan
| | - Tomoyo Yoshida-Uemura
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan
| | - Akira Arakawa
- Department of Ophthalmology, Yokohama City University Medical Center, Yokohama, Japan
| | - Sachiko Nishina
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan
| | - Kazuaki Kadonosono
- Department of Ophthalmology, Yokohama City University Medical Center, Yokohama, Japan
| | - Noriyuki Azuma
- Department of Ophthalmology and Laboratory for Visual Science, National Center for Child Health and Development, Tokyo, Japan
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7
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Lai YH, Huang SP, Chen SP, Hu PS, Lin SF, Sheu MM, Wang HZ, Tsai RK. A novel gene mutation in a family with X-linked retinoschisis. J Formos Med Assoc 2015; 114:872-80. [DOI: 10.1016/j.jfma.2014.01.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Revised: 01/01/2014] [Accepted: 01/08/2014] [Indexed: 10/25/2022] Open
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8
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Huang CT, Chen SP, Tsai RK. The gene mutation in a Taiwanese family with X-linked retinoschisis. Kaohsiung J Med Sci 2015; 31:309-14. [PMID: 26043410 DOI: 10.1016/j.kjms.2015.03.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 02/13/2015] [Accepted: 02/24/2015] [Indexed: 11/15/2022] Open
Abstract
X-linked retinoschisis (XLRS) is one of the leading causes of macular degeneration in male children. The purpose of this study is to describe the clinical characteristics of a Taiwanese family with X-linked retinoschisis (XLRS) and to investigate the genetic mutation in the retinoschisin 1 (RS1) gene. A total of four participants in this XLRS family were analyzed. Complete ophthalmic examinations were performed, including best corrected visual acuity, optical coherence tomography (OCT), and electroretinogram (ERG). Direct DNA sequence of the RS1 gene identified one affected male and one female carrier. The affected male, had a cartwheel-like macular appearance and abnormal retinal pigment epithelium pigmentation in his bilateral eyes. The mixed scotopic ERG b-wave was more reduced than a-wave. OCT revealed typical macular microcystic schisis cavities. Direct DNA sequence analysis revealed a single base pair substitution in Exon 4, 304C > T, resulting in Arg102Trp. Our results show a RS1 (304C > T) mutation in a Taiwanese family with XLRS. This finding expands the clinical profiles of RS1 mutation and may help to further understand its pathogenesis.
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Affiliation(s)
- Chin-Te Huang
- Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Shee-Ping Chen
- Tzu Chi Stem Cells Center, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Rong-Kung Tsai
- Institute of Medical Sciences, Tzu Chi University, Hualien, Taiwan; Institute of Eye Research, Buddhist Tzu Chi General Hospital, Hualien, Taiwan.
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9
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Abstract
X-linked juvenile retinoschisis (XLRS) is one of the most common genetic causes of juvenile progressive retinal-vitreal degeneration in males. To date, more than 196 different mutations of the RS1 gene have been associated with XLRS. The mutation spectrum is large and the phenotype variable. This review will focus on the clinical features of XLRS and examine the relationship between phenotype and genotype.
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Affiliation(s)
- David Y Kim
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston , Massachusetts , USA
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10
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Sergeev YV, Vitale S, Sieving PA, Vincent A, Robson AG, Moore AT, Webster AR, Holder GE. Molecular modeling indicates distinct classes of missense variants with mild and severe XLRS phenotypes. Hum Mol Genet 2013; 22:4756-67. [PMID: 23847049 DOI: 10.1093/hmg/ddt329] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
X-linked retinoschisis (XLRS) is a vitreo-retinal degeneration caused by mutations in the RS1 gene which encodes the protein retinoschisin (RS1), required for the structural and functional integrity of the retina. Data are presented from a group of 38 XLRS patients from Moorfields Eye Hospital (London, UK) who had one of 18 missense mutations in RS1. Patients were grouped based on mutation severity predicted by molecular modeling: mild (class I), moderate (intermediate) and severe (class II). Most patients had an electronegative scotopic bright flash electroretinogram (ERG) (reduced b/a-wave ratio) in keeping with predominant inner retinal dysfunction. An association between the type of structural RS1 alterations and the severity of b/a-wave reduction was found in all but the oldest group of patients, significant in patients aged 15-30 years. Severe RS1 missense changes were associated with a lower ERG b/a ratio than were mild changes, suggesting that the extent of inner retinal dysfunction is influenced by the effect of the mutations on protein structure. The majority of class I mutations showed no changes involving cysteine residues. Class II mutations caused severe perturbations due to the removal or insertion of cysteine residues or due to changes in the hydrophobic core. The ERG b/a ratio in intermediate cases was abnormal but showed significant variability, possibly related to the role of proline or arginine residues. We also conducted a second study, using a completely independent cohort, to indicate a genotype-ERG phenotype correlation.
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11
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Vincent A, Robson AG, Neveu MM, Wright GA, Moore AT, Webster AR, Holder GE. A phenotype-genotype correlation study of X-linked retinoschisis. Ophthalmology 2013; 120:1454-64. [PMID: 23453514 DOI: 10.1016/j.ophtha.2012.12.008] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Revised: 12/06/2012] [Accepted: 12/06/2012] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To compare the clinical phenotype and detailed electroretinographic parameters in X-linked retinoschisis (XLRS). DESIGN Retrospective, comparative study. PARTICIPANTS Fifty-seven patients (aged 1-67 years) with molecularly confirmed XLRS were clinically ascertained. METHODS Pattern electroretinography (PERG) and full-field electroretinography (ERG), incorporating international standard recordings, were performed in 44 cases. Thirteen patients, mostly pediatric, were tested using a simplified ERG protocol. On-Off and S-cone ERGs were performed in most adults. Fundus autofluorescence (FAF) imaging and optical coherence tomography (OCT) were available in 17 and 21 cases, respectively. MAIN OUTCOME MEASURES The clinical and electrophysiologic data associated with different types of mutation in the RS1 gene. RESULTS Forty-three patients had missense changes (group A), and 14 patients had nonsense, splice-site, or frame-shifting mutations in the RS1 gene (group B). The mean best-corrected visual acuity was better in group A than in group B (0.34 and 0.21, respectively). Fundus examination revealed foveal schisis in approximately half of both groups. The bright-flash dark-adapted (DA) ERG (11.0 candela.sec.m(-2)) waveform was electronegative in 62% of group A eyes and 100% of group B eyes. The photopic 30-Hz flicker ERG was delayed in all group B eyes and all except 6 group A eyes. On-Off ERG b-waves were subnormal in 39% of group A and 89% of group B eyes; d-waves were delayed in 14 eyes (group A = 10, group B = 4). S-cone ERGs were abnormal in 50% of both groups. The PERG was abnormal in 88% of group A and 100% of group B eyes. A spoke-wheel pattern of high and low intensity was the most common FAF abnormality observed. The OCT showed intraretinal schitic cavities in the majority of eyes. CONCLUSIONS There is profound phenotypic variability in patients with XLRS. Most patients have DA bright-flash ERGs with a low b:a ratio in keeping with inner retinal dysfunction. Generalized cone system dysfunction is common and associated with an abnormal On-response and less frequent additional Off-response involvement. Nonsense, splice-site, or frame-shifting mutations in RS1 consistently caused electronegative bright-flash ERG, delayed flicker response, and abnormal PERG; missense mutations result in a wider range of ERG abnormalities.
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Affiliation(s)
- Ajoy Vincent
- Moorfields Eye Hospital, City Road, London, United Kingdom
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12
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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: 208] [Impact Index Per Article: 17.3] [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.
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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.
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Vijayasarathy C, Sui R, Zeng Y, Yang G, Xu F, Caruso RC, Lewis RA, Ziccardi L, Sieving PA. Molecular mechanisms leading to null-protein product from retinoschisin (RS1) signal-sequence mutants in X-linked retinoschisis (XLRS) disease. Hum Mutat 2010; 31:1251-60. [PMID: 20809529 DOI: 10.1002/humu.21350] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Retinoschisin (RS1) is a cell-surface adhesion molecule expressed by photoreceptor and bipolar cells of the retina. The 24-kDa protein encodes two conserved sequence motifs: the initial signal sequence targets the protein for secretion while the larger discoidin domain is implicated in cell adhesion. RS1 helps to maintain the structural organization of the retinal cell layers and promotes visual signal transduction. RS1 gene mutations cause X-linked retinoschisis disease (XLRS) in males, characterized by early-onset central vision loss. We analyzed the biochemical consequences of several RS1 signal-sequence mutants (c.1A>T, c.35T>A, c.38T>C, and c.52G>A) found in our subjects. Expression analysis in COS-7 cells demonstrates that these mutations affect RS1 biosynthesis and result in an RS1 null phenotype by several different mechanisms. By comparison, discoidin-domain mutations generally lead to nonfunctional conformational variants that remain trapped inside the cell. XLRS disease has a broad heterogeneity in general, but subjects with the RS1 null-protein signal-sequence mutations are on the more severe end of the clinical phenotype. Results from the signal-sequence mutants are discussed in the context of the discoidin-domain mutations, clinical phenotypes, genotype-phenotype correlations, and implications for RS1 gene replacement therapy.
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Affiliation(s)
- Camasamudram Vijayasarathy
- Section on Translational Research for Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health (NIH), Bethesda, Maryland 20892, USA
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Sergeev YV, Caruso RC, Meltzer MR, Smaoui N, MacDonald IM, Sieving PA. Molecular modeling of retinoschisin with functional analysis of pathogenic mutations from human X-linked retinoschisis. Hum Mol Genet 2010; 19:1302-13. [PMID: 20061330 DOI: 10.1093/hmg/ddq006] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Gene mutations that encode retinoschisin (RS1) cause X-linked retinoschisis (XLRS), a form of juvenile macular and retinal degeneration that affects males. RS1 is an adhesive protein which is proposed to preserve the structural and functional integrity of the retina, but there is very little evidence of the mechanism by which protein changes are related to XLRS disease. Here, we report molecular modeling of the RS1 protein and consider perturbations caused by mutations found in human XLRS subjects. In 60 XLRS patients who share 27 missense mutations, we then evaluated possible correlations of the molecular modeling with retinal function as determined by the electroretinogram (ERG) a- and b-waves. The b/a-wave ratio reflects visual-signal transfer in retina. We sorted the ERG b/a-ratios by patient age and by the mutation impact on protein structure. The majority of RS1 mutations caused minimal structure perturbation and targeted the protein surface. These patients' b/a-ratios were similar across younger and older subjects. Maximum structural perturbations from either the removal or insertion of cysteine residues or changes in the hydrophobic core were associated with greater difference in the b/a-ratio with age, with a significantly smaller ratio at younger ages, analogous to the ERG changes with age observed in mice with no RS1-protein expression due to a recombinant RS1-knockout gene. The molecular modeling suggests an association between the predicted structural alteration and/or damage to retinoschisin and the severity of XLRS as measured by the ERG analogous to the RS1-knockout mouse.
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Affiliation(s)
- Y V Sergeev
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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Kim DY, Neely KA, Sassani JW, Vrabec TR, Tantri A, Frost A, Donoso LA. X-linked retinoschisis: novel mutation in the initiation codon of the XLRS1 gene in a large family. Retina 2006; 26:940-6. [PMID: 17031297 DOI: 10.1097/01.iae.0000224321.93502.a3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe a novel point mutation in the initiation codon of the XLRS1 gene in a large family and the clinical features of males affected with X-linked juvenile retino-schisis. METHODS Genealogic investigation and mutation screening of the XLRS1 gene were performed for a 4-generation family consisting of 72 members. Affected males were evaluated clinically between 1986 and 2004 with up to 18 years of follow-up. RESULTS We identified a novel point mutation (1A>T transversion) in the initiation codon of the XLRS1 gene in affected males resulting in an amino acid substitution of methionine to leucine (Met1Leu), therefore abolishing the translation initiation Met codon. CONCLUSION Identification of the disease-causing mutation in this family with long-term follow-up allows for earlier and more accurate identification of individuals at risk for this inherited progressive macular degeneration, provides for more accurate genetic counseling, and contributes to our understanding of the pathophysiology of this disorder.
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Affiliation(s)
- David Y Kim
- Henry and Corinne Bower Laboratory, Wills Eye Hospital and the Eye Research Institute, 211 South 9th Street, Room 402, Philadelphia, PA 19107, USA
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Iannaccone A, Mura M, Dyka FM, Ciccarelli ML, Yashar BM, Ayyagari R, Jablonski MM, Molday RS. An unusual X-linked retinoschisis phenotype and biochemical characterization of the W112C RS1 mutation. Vision Res 2006; 46:3845-52. [PMID: 16884758 DOI: 10.1016/j.visres.2006.06.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2006] [Revised: 06/02/2006] [Accepted: 06/09/2006] [Indexed: 10/24/2022]
Abstract
A 52-year-old subject harboring an RS1 gene W112C mutation presented with a prominent and asymmetric tapetal-like retinal sheen. Transient ERG responses were smaller and slower in the eye with the more extensive sheen, an association that, to our knowledge, had not been previously reported. An ON-pathway dysfunction explained the abnormalities of the transient but not those of the flicker ERGs. Although in vitro studies showed that the W112C mutant retinoschisin is present only in the cellular fraction and is not secreted, disease expression was remarkably mild, consistent with the notion of the existence of genetic and/or epigenetic disease modifiers.
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Affiliation(s)
- Alessandro Iannaccone
- Hamilton Eye Institute, Department of Ophthalmology, University of Tennessee Health Science Center, 930 Madison Avenue, Suite 731, Memphis, TN 38163, USA.
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Prasad A, Wagner R, Bhagat N. Vitreous hemorrhage as the initial manifestation of X-linked retinoschisis in a 9-month-old infant. J Pediatr Ophthalmol Strabismus 2006; 43:56-8. [PMID: 16491731 DOI: 10.3928/01913913-20060101-12] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A 9-month-old infant presented with progressive esotropia, bilateral vitreous hemorrhages, bullous retinoschises, and peripheral retinal detachments. X-linked retinoschisis was diagnosed on the basis of electroretinogram findings. We report a case of vitreous hemorrhage as the initial presentation of X-linked retinoschisis in one of the youngest patients discussed in the literature.
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Affiliation(s)
- Archna Prasad
- Institute of Ophthalmology and Visual Science, New Jersey Medical School, Newark, New Jersey, USA
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Kłosowska-Zawadka A, Bernardczyk-Meller J, Gotz-Wieckowska A, Krawczyński M. [Importance of family examination in juvenile X-linked retinoschisis]. Ophthalmologe 2004; 102:1193-9. [PMID: 15349747 DOI: 10.1007/s00347-004-1105-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Congenital (juvenile) retinoschisis belongs to the group of hereditary vitreoretinopathies. This disorder is inherited in an X-linked recessive pattern and its onset usually occurs in 5- to 10-year-old boys. Presenting clinical signs include decreased visual acuity due to maculopathy. CASE REPORT The authors present a case of a 17-year-old boy with decreased visual acuity, hypermetropia, and bilateral retinoschisis with maculopathy upon fundus examination. In view of a 50% risk of the disorder occurring in the brothers of the affected male, they underwent full ophthalmological and electrophysiological examinations (until then asymptomatic). In one of them decreased visual acuity, mixed astigmatism, and maculopathy were present, without any changes of the peripheral retina. In the youngest brother decreased visual acuity, hypermetropia, and maculopathy were diagnosed. CONCLUSIONS Genetic counseling and ophthalmological examination of family members at risk facilitated early recognition of the pathological changes in the siblings. Genetic counseling with pedigree analysis and genetic analysis, if possible, should be offered to all affected patients and family members.
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Shinoda K, Ohde H, Mashima Y, Inoue R, Ishida S, Inoue M, Kawashima S, Oguchi Y. On- and off-responses of the photopic electroretinograms in X-linked juvenile retinoschisis. Am J Ophthalmol 2001; 131:489-94. [PMID: 11292413 DOI: 10.1016/s0002-9394(00)00858-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
PURPOSE To examine the physiologic condition of the middle retinal layer of patients with X-linked juvenile retinoschisis (xlRS) by studying the on- and off-responses of the photopic electroretinograms (ERGs). METHODS Eleven unrelated Japanese men (mean age; 24.9 +/- 7.6 years) who were clinically diagnosed with xlRS and molecularly confirmed as having XLRS1 mutations were investigated. For the photopic ERGs, the a-, b- and d-wave amplitudes elicited by long duration stimuli were recorded, and the responses from the xlRS patients were compared to those recorded from normal subjects (n = 14, mean age, 27.5 +/- 4.5 years). We also examined the relationship between the photopic ERG responses and the genotype. RESULTS No significant difference was found between the a- and d-wave amplitudes in the xlRS patients (34.2 +/- 8.7 microV, 52.5 +/- 10.4 microV, respectively), and those in normal subjects (40.4 +/- 10.3 microV, 44.7 +/- 6.3 microV, respectively). The mean b-wave amplitude in the xlRS patients was significantly smaller (10.5 +/- 7.7 microV) than the mean of normal subjects (46.4 +/- 10.2 microV) (P < 0.0001). No significant correlation was found between the ERG responses and the locus of the mutation. CONCLUSION The photopic ERG demonstrated considerable impairment of the on-pathway arising from an abnormality of the on-bipolar cells or possibly secondary to Müller cell abnormality in xlRS.
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Affiliation(s)
- K Shinoda
- Department of Ophthalmology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
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