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Vijayasarathy C, Zeng Y, Brooks MJ, Fariss RN, Sieving PA. Genetic Rescue of X-Linked Retinoschisis Mouse ( Rs1-/y) Retina Induces Quiescence of the Retinal Microglial Inflammatory State Following AAV8- RS1 Gene Transfer and Identifies Gene Networks Underlying Retinal Recovery. Hum Gene Ther 2020; 32:667-681. [PMID: 33019822 PMCID: PMC8312029 DOI: 10.1089/hum.2020.213] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To understand RS1 gene interaction networks in the X-linked retinoschisis (XLRS) mouse retina (Rs1-/y), we analyzed the transcriptome by RNA sequencing before and after in vivo expression of exogenous retinoschisin (RS1) gene delivered by AAV8. RS1 is a secreted cell adhesion protein that is critical for maintaining structural lamination and synaptic integrity of the neural retina. RS1 loss-of-function mutations cause XLRS disease in young boys and men, with splitting ("schisis") of retinal layers and synaptic dysfunction that cause progressive vision loss with age. Analysis of differential gene expression profiles and pathway enrichment analysis of Rs1-KO (Rs1-/y) retina identified cell surface receptor signaling and positive regulation of cell adhesion as potential RS1 gene interaction networks. Most importantly, it also showed massive dysregulation of immune response genes at early age, with characteristics of a microglia-driven proinflammatory state. Delivery of AAV8-RS1 primed the Rs1-KO retina toward structural and functional recovery. The disease transcriptome transitioned toward a recovery phase with upregulation of genes implicated in wound healing, anatomical structure (camera type eye) development, metabolic pathways, and collagen IV networks that provide mechanical stability to basement membrane. AAV8-RS1 expression also attenuated the microglia gene signatures to low levels toward immune quiescence. This study is among the first to identify RS1 gene interaction networks that underlie retinal structural and functional recovery after RS1 gene therapy. Significantly, it also shows that providing wild-type RS1 gene function caused the retina immune status to transition from a degenerative inflammatory phenotype toward immune quiescence, even though the transgene is not directly linked to microglia function. This study indicates that inhibition of microglial proinflammatory responses is an integral part of therapeutic rescue in XLRS gene therapy, and gene therapy might realize its full potential if delivered before microglia activation and photoreceptor cell death. Clinical Trials. gov Identifier NTC 02317887.
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Affiliation(s)
| | - Yong Zeng
- Section for Translational Research in Retinal and Macular Degeneration
| | | | - Robert N Fariss
- Biological Imaging Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Paul A Sieving
- Department of Ophthalmology, Center for Ocular Regenerative Therapy, School of Medicine, University of California at Davis, Sacramento, CA, USA
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Kim S, Thomasy SM, Raghunathan VK, Teixeira LB, Moshiri A, FitzGerald P, Murphy CJ. Ocular phenotypic consequences of a single copy deletion of the Yap1 gene ( Yap1 +/-) in mice. Mol Vis 2019; 25:129-142. [PMID: 30820148 PMCID: PMC6382475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 02/15/2019] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To identify the effects of a single copy deletion of Yap1 (Yap1 +/-) in the mouse eye, the ocular phenotypic consequences of Yap1 +/- were determined in detail. METHODS Complete ophthalmic examinations, as well as corneal esthesiometry, the phenol red thread test, intraocular pressure, and Fourier-domain optical coherence tomography were performed on Yap1 +/- and age-matched wild-type (WT) mice between eyelid opening (2 weeks after birth) and adulthood (2 months and 1 year after birth). Following euthanasia, enucleated eyes were characterized histologically. RESULTS Microphthalmia with small palpebral fissures, corneal fibrosis, and reduced corneal sensation were common findings in the Yap1 +/- mice. Generalized corneal fibrosis precluded clinical examination of the posterior structures. Histologically, thinning and keratinization of the corneal epithelium were observed in the Yap1 +/- mice in comparison with the WT mice. Distorted collagen fiber arrangement and hypercellularity of keratocytes were observed in the stroma. Descemet's membrane was extremely thin and lacked an endothelial layer in the Yap1 +/- mice. The iris was adherent to the posterior cornea along most of its surface creating a distorted contour. Most of the Yap1 +/- eyes were microphakic with swollen fibers and bladder cells. The retinas of the Yap1 +/- mice were normal at 2 weeks and 2 months of age, but the presence of retinal abnormalities, including retinoschisis and detachment, was markedly increased in the Yap1 +/- mice at 1 year of age. CONCLUSIONS The results show that the heterozygous deletion of the Yap1 gene in mice leads to complex ocular abnormalities, including microphthalmia, corneal fibrosis, anterior segment dysgenesis, and cataract.
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Affiliation(s)
- Soohyun Kim
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA
| | - Sara M. Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA,Department of Ophthalmology & Vision Science, School of Medicine, School of Medicine, University of California Davis, Davis, CA
| | - Vijay Krishna Raghunathan
- Department of Basic Sciences, College of Optometry, University of Houston, Houston, TX,The Ocular Surface Institute, College of Optometry, University of Houston, Houston, TX,Department of Biomedical Engineering, Cullen College of Engineering, University of Houston, Houston, TX
| | - Leandro B.C. Teixeira
- Comparative Ocular Pathology Laboratory of Wisconsin, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI
| | - Ala Moshiri
- Department of Ophthalmology & Vision Science, School of Medicine, School of Medicine, University of California Davis, Davis, CA
| | - Paul FitzGerald
- Department of Ophthalmology & Vision Science, School of Medicine, School of Medicine, University of California Davis, Davis, CA,Department of Cell Biology and Human Anatomy, School of Medicine, School of Medicine, University of California Davis, Davis, CA
| | - Christopher J. Murphy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA,Department of Ophthalmology & Vision Science, School of Medicine, School of Medicine, University of California Davis, Davis, CA
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Meyer KJ, Anderson MG. Genetic modifiers as relevant biological variables of eye disorders. Hum Mol Genet 2017; 26:R58-R67. [PMID: 28482014 DOI: 10.1093/hmg/ddx180] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 05/05/2017] [Indexed: 12/19/2022] Open
Abstract
From early in the study of mammalian genetics, it was clear that modifiers can have a striking influence on phenotypes. Today, several modifiers have now been studied in enough detail to allow a glimpse of how they function and influence our perspective of disease. With respect to diseases of the eye, some modifiers are an important source of phenotypic variation that can elucidate how genes function in networks to collectively shape ocular anatomy and physiology, thus influencing our understanding of basic biology. Other modifiers represent an opportunity for new therapeutic targets, whose manipulation could be used to mitigate ophthalmic disease. Here, we review progress in the study of genetic modifiers of eye disorders, with examples from mice and humans that together illustrate the ubiquitous nature of genetic modifiers and why they are relevant biological variables in experimental design. Special emphasis is given to ophthalmic modifiers in mice, especially those relevant to selection of genetic background and those that might inadvertently be a source of experimental variability. These modifiers are capable of influencing interpretations of many experiments using targeted genome manipulations such as knockouts or transgenics. Whereas there are fewer examples of modifiers of eye disorders in humans with a molecular identification, there is ample evidence that they exist and should be considered as a relevant biological variable in human genetic studies as well.
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Affiliation(s)
- Kacie J Meyer
- Department of Molecular Physiology and Biophysics.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA
| | - Michael G Anderson
- Department of Molecular Physiology and Biophysics.,Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA.,Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, IA 52242, USA.,Center for Prevention and Treatment of Visual Loss, Iowa City Veterans Administration Medical Center, Iowa City, IA 52242, USA
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Xiao Y, Liu X, Tang L, Wang X, Coursey TG, Coursy T, Guo X, Li Z. X-Linked Retinoschisis: Phenotypic Variability in a Chinese Family. Sci Rep 2016; 6:20118. [PMID: 26823236 PMCID: PMC4731765 DOI: 10.1038/srep20118] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 12/29/2015] [Indexed: 11/09/2022] Open
Abstract
X-linked juvenile retinoschisis (XLRS), a leading cause of juvenile macular degeneration, is characterized by a spoke-wheel pattern in the macular region of the retina and splitting of the neurosensory retina. Our study is to describe the clinical characteristics of a four generations of this family (a total of 18 members)with X-linked retinoschisis (XLRS) and detected a novel mutations of c.3G > A (p.M1?) in the initiation codon of the RS1 gene. by direct sequencing.Identification of this mutation in this family provides evidence about potential genetic or environmental factors on its phenotypic variance, as patients presented with different phenotypes regardless of having the same mutation. Importantly, OCT has proven vital for XLRS diagnosis in children.
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Affiliation(s)
- Yangyan Xiao
- Department of Ophthalmology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiao Liu
- Department of Ophthalmology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Luosheng Tang
- Department of Ophthalmology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xia Wang
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | | | - Terry Coursy
- Cullen eye institute, Baylor College of Medicine, Houston, Texas, USA
| | - Xiaojian Guo
- Department of Ophthalmology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Zhuo Li
- Department of Ophthalmology, Second Xiangya Hospital, Central South University, Changsha, Hunan, China
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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
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Won J, Charette JR, Philip VM, Stearns TM, Zhang W, Naggert JK, Krebs MP, Nishina PM. Genetic modifier loci of mouse Mfrp(rd6) identified by quantitative trait locus analysis. Exp Eye Res 2013; 118:30-5. [PMID: 24200520 DOI: 10.1016/j.exer.2013.10.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Accepted: 10/27/2013] [Indexed: 11/25/2022]
Abstract
The identification of genes that modify pathological ocular phenotypes in mouse models may improve our understanding of disease mechanisms and lead to new treatment strategies. Here, we identify modifier loci affecting photoreceptor cell loss in homozygous Mfrp(rd6) mice, which exhibit a slowly progressive photoreceptor degeneration. A cohort of 63 F2 homozygous Mfrp(rd6) mice from a (B6.C3Ga-Mfrp(rd6)/J × CAST/EiJ) F1 intercross exhibited a variable number of cell bodies in the retinal outer nuclear layer at 20 weeks of age. Mice were genotyped with a panel of single nucleotide polymorphism markers, and genotypes were correlated with phenotype by quantitative trait locus (QTL) analysis to map modifier loci. A genome-wide scan revealed a statistically significant, protective candidate locus on CAST/EiJ Chromosome 1 and suggestive modifier loci on Chromosomes 6 and 11. Multiple regression analysis of a three-QTL model indicated that the modifier loci on Chromosomes 1 and 6 together account for 26% of the observed phenotypic variation, while the modifier locus on Chromosome 11 explains only an additional 4%. Our findings indicate that the severity of the Mfrp(rd6) retinal degenerative phenotype in mice depends on the strain genetic background and that a significant modifier locus on CAST/EiJ Chromosome 1 protects against Mfrp(rd6)-associated photoreceptor loss.
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Affiliation(s)
- Jungyeon Won
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | | | - Vivek M Philip
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | | | - Weidong Zhang
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Jürgen K Naggert
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Mark P Krebs
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
| | - Patsy M Nishina
- The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA.
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Kawakami-Schulz SV, Sattler SG, Doebley AL, Ikeda A, Ikeda S. Genetic modification of corneal neovascularization in Dstn (corn1) mice. Mamm Genome 2013; 24:349-57. [PMID: 23929036 PMCID: PMC3802551 DOI: 10.1007/s00335-013-9468-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/05/2013] [Indexed: 10/26/2022]
Abstract
Mutations in the gene for destrin (Dstn), an actin depolymerizing factor, lead to corneal abnormalities in mice. A null mutation in Dstn, termed Dstn (corn1) , isolated and maintained in the A.BY background (A.BY Dstn (corn1) ), results in corneal epithelial hyperproliferation, inflammation, and neovascularization. We previously reported that neovascularization in the cornea of Dstn (corn1) mice on the C57BL/6 background (B6.A.BY-Dstn (corn1) ) is significantly reduced when compared to A.BY Dstn (corn1) mice, suggesting the existence of genetic modifier(s). The purpose of this study is to identify the genetic basis of the difference in corneal neovascularization between A.BY Dstn (corn1) and B6.A.BY-Dstn (corn1) mice. We generated N2 mice for a whole-genome scan by backcrossing F1 progeny (A.BY Dstn (corn1) × B6.A.BY-Dstn (corn1) ) to B6.A.BY-Dstn (corn1) mice. N2 progeny were quantitatively phenotyped for the extent of corneal neovascularization and genotyped for markers across the mouse genome. We identified significant association of variability in corneal neovascularization with a locus on chromosome 3 (Chr3). The validity of the identified quantitative trait locus (QTL) was tested using B6 consomic mice carrying Chr3 from A/J mice. Dstn (corn1) mice from F1 and F2 intercrosses (B6.A.BY-Dstn (corn1) × C57BL/6J-Chr3(A/J)/NaJ) were phenotyped for the extent of corneal neovascularization. This analysis showed that mice carrying the A/J allele at the QTL show significantly increased neovascularization. Our results indicate the existence of a modifier that genetically interacts with the Dstn gene. This modifier demonstrates allelic differences between C57BL6 and A.BY or A/J. The modifier is sufficient to increase neovascularization in Dstn (corn1) mice.
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Affiliation(s)
| | - Shannon G. Sattler
- Department of Medical Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Anna-Lisa Doebley
- Department of Medical Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Akihiro Ikeda
- Department of Medical Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - Sakae Ikeda
- Department of Medical Genetics, University of Wisconsin, Madison, Wisconsin 53706, USA
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Jelcick AS, Yuan Y, Leehy BD, Cox LC, Silveira AC, Qiu F, Schenk S, Sachs AJ, Morrison MA, Nystuen AM, DeAngelis MM, Haider NB. Genetic variations strongly influence phenotypic outcome in the mouse retina. PLoS One 2011; 6:e21858. [PMID: 21779340 PMCID: PMC3136482 DOI: 10.1371/journal.pone.0021858] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 06/07/2011] [Indexed: 01/22/2023] Open
Abstract
Variation in genetic background can significantly influence the phenotypic outcome of both disease and non-disease associated traits. Additionally, differences in temporal and strain specific gene expression can also contribute to phenotypes in the mammalian retina. This is the first report of microarray based cross-strain analysis of gene expression in the retina investigating genetic background effects. Microarray analyses were performed on retinas from the following mouse strains: C57BL6/J, AKR/J, CAST/EiJ, and NOD.NON-H2-nb1 at embryonic day 18.5 (E18.5) and postnatal day 30.5 (P30.5). Over 3000 differentially expressed genes were identified between strains and developmental stages. Differential gene expression was confirmed by qRT-PCR, Western blot, and immunohistochemistry. Three major gene networks were identified that function to regulate retinal or photoreceptor development, visual perception, cellular transport, and signal transduction. Many of the genes in these networks are implicated in retinal diseases such as bradyopsia, night-blindness, and cone-rod dystrophy. Our analysis revealed strain specific variations in cone photoreceptor cell patterning and retinal function. This study highlights the substantial impact of genetic background on both development and function of the retina and the level of gene expression differences tolerated for normal retinal function. These strain specific genetic variations may also be present in other tissues. In addition, this study will provide valuable insight for the development of more accurate models for human retinal diseases.
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Affiliation(s)
- Austin S. Jelcick
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Yang Yuan
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Barrett D. Leehy
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Lakeisha C. Cox
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Alexandra C. Silveira
- Ocular Molecular Genetics Institute, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States of America
| | - Fang Qiu
- Division of Biostatistics, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Sarah Schenk
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Andrew J. Sachs
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Margaux A. Morrison
- Ocular Molecular Genetics Institute, Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, United States of America
| | - Arne M. Nystuen
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska, United States of America
| | - Margaret M. DeAngelis
- Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
| | - Neena B. Haider
- Department of Ophthalmology, Harvard Medical School, Schepens Eye Research Institute, Boston, Massachusetts, United States of America
- * E-mail:
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Xu F, Xiang H, Jiang R, Dong F, Sui R. Phenotypic expression of X-linked retinoschisis in Chinese families with mutations in the RS1 gene. Doc Ophthalmol 2011; 123:21-7. [PMID: 21701876 DOI: 10.1007/s10633-011-9278-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Accepted: 06/09/2011] [Indexed: 10/18/2022]
Abstract
To assess the clinical features of and identify genetic defects in six Chinese families with X-linked retinoschisis (XLRS). Patients were recruited from ophthalmic clinics in Peking Union Medical College Hospital. A cohort of six unrelated families was identified. Clinical evaluation was performed on eight affected males (six probands) and five female carriers. Genomic DNA was extracted from peripheral leukocytes. All exons and the flanking introns of the RS1 gene were amplified by polymerase chain reaction and screened for mutations by direct DNA sequencing. One hundred control X chromosomes were screened by direct sequencing to exclude nonpathogenic polymorphisms. Typical foveal schisis was found in all eight patients, while peripheral schisis was noted in six patients. The six probands displayed electronegative electroretinography (ERG) in the standard combined response, while the remaining two patients showed non-recordable waveforms. Two novel mutations (W112X and S134P) and three previously identified missense mutations (R102Q, R200H, and R213W) were found. None of these novel nucleotide variations were observed in any of 100 ethnically matched control chromosomes. Chinese patients with XLRS displayed variability in phenotypes. Novel mutations in RS1 were associated with these patients. Identification of the disease-causing mutations in suspected families can help to confirm the diagnosis for the patients and recommend genetic counseling for the female carriers. In addition, genetic testing could provide important information for future treatment.
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Affiliation(s)
- Fei Xu
- Department of Ophthalmology, Peking Union Medical College Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Shuai Fu Yuan, Beijing, China.
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Abstract
X-linked retinoschisis (XLRS) is a form of macular degeneration with a juvenile onset. This disease is caused by mutations in the retinoschisin (RS1) gene. The major clinical pathologies of this disease include splitting of the retina (schisis) and a loss in synaptic transmission. Human XLRS patients display a broad range in phenotypic severity, even among family members with the same mutation. This variation suggests the existence of genetic modifiers that may contribute to disease severity. Previously, we reported the identification of a modifier locus, named Mor1, which affects severity of schisis in a mouse model of XLRS (the Rs1tmgc1 mouse). Homozygosity for the protective AKR allele of Mor1 restores cell adhesion in Rs1tmgc1 mice. Here, we report our study to identify the Mor1 gene. Through collecting recombinant mice followed by progeny testing, we have localized Mor1 to a 4.4-Mb region on chromosome 7. In this genetic region, the AKR strain is known to carry a mutation in the tyrosinase (Tyr) gene. We observed that the schisis phenotype caused by the Rs1 mutation is rescued by a Tyr mutation in the C57BL/6J genetic background, strongly suggesting that Tyr is the Mor1 gene.
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Yu J, Ni Y, Keane PA, Jiang C, Wang W, Xu G. Foveomacular schisis in juvenile X-linked retinoschisis: an optical coherence tomography study. Am J Ophthalmol 2010; 149:973-978.e2. [PMID: 20430364 DOI: 10.1016/j.ajo.2010.01.031] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Revised: 01/15/2010] [Accepted: 01/15/2010] [Indexed: 11/18/2022]
Abstract
PURPOSE To explore the structural features of juvenile X-linked retinoschisis using spectral-domain optical coherence tomography (OCT). DESIGN Retrospective, observational cross-sectional study. METHODS Eighteen male patients (34 eyes) who were diagnosed with juvenile X-linked retinoschisis at the Eye & ENT Hospital of Fudan University over an 18-month period were included. Their OCT images, which were obtained using spectral-domain OCT (Cirrus HD-OCT; Carl Zeiss Meditec), were analyzed. The anatomic location of the schisis cavity in juvenile X-linked retinoschisis was characterized by direct inspection of OCT images. RESULTS On OCT, the schisis cavity was visible at the fovea in all 34 eyes, and it was associated with increased retinal thickness. Schisis was present at the retinal nerve fiber layer in 4 eyes, at the inner nuclear layer in 29 eyes, and at the outer nuclear layer/outer plexiform layer in 22 eyes. In most cases, widespread foveomacular schisis was detected using OCT; however, in 9 eyes (6 patients), the schisis was confined to the fovea. Schisis of the inner nuclear layer and outer nuclear layer/outer plexiform layer almost always involved the foveal center, but retinal nerve fiber layer schisis was seen only in the parafoveal area. CONCLUSIONS Despite conventional wisdom, in patients with X-linked retinoschisis, the schisis cavity can occur in a number of different layers of the neurosensory retina (retinal nerve fiber layer, inner nuclear layer, and outer nuclear layer/outer plexiform layer). In addition, different forms of schisis may affect different locations in the macula (foveal vs parafoveal), and, in most eyes, the schisis involves the entire foveomacular region.
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Affiliation(s)
- Jia Yu
- Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, People's Republic of China
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Abstract
PURPOSE OF REVIEW The aim of this review is to highlight recent advances in our understanding of the molecular genetic basis and phenotype of childhood onset macular dystrophies and to summarize current attempts to develop novel therapies for this group of disorders. RECENT FINDINGS The genes associated with the major causes of childhood onset macular dystrophies have now been identified and current research efforts have been focused on understanding the function of the encoded protein, how the mutant protein leads to photoreceptor cell death and investigation of the range of retinal phenotypes that result from mutations in these genes. Assessment of the phenotype has been greatly helped by improvements in retinal imaging such as spectral domain optical coherence tomography and fundus autofluorescence imaging. The development of animal models has, despite their limitations, helped understanding of disease mechanisms and allowed assessment of new therapeutic approaches such as gene replacement therapy and pharmacological treatments. SUMMARY Molecular diagnosis and improvements in retinal imaging have greatly improved the accuracy of diagnosis in paediatric macular disease and allowed better genetic counselling and information about prognosis to be given to children and their families. Advances in basic understanding of disease mechanism will lead to the development of clinical trials of novel therapies in the near future.
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Vijayasarathy C, Ziccardi L, Zeng Y, Smaoui N, Caruso RC, Sieving PA. Null retinoschisin-protein expression from an RS1 c354del1-ins18 mutation causing progressive and severe XLRS in a cross-sectional family study. Invest Ophthalmol Vis Sci 2009; 50:5375-83. [PMID: 19474399 DOI: 10.1167/iovs.09-3839] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To explore the retinoschisin (RS1) protein biochemical phenotype from an RS1 exon-5 deletion/insertion frame-shift mutation in a family with X-linked retinoschisis (XLRS) and describe the clinical and electrophysiological features. METHODS Six XLRS males underwent ophthalmic examination and electroretinogram (ERG) recording. The RS1 gene was sequenced. Mutant RS1-RNA and protein expression were assessed by transfecting COS-7 cells with minigene constructs. RESULTS All six males carried the RS1 c354del1-ins18 mutation in which an 18-bp insertion replaced nucleotide 354, duplicating the adjacent upstream intron 4-to-exon 5 junction and creating a premature termination codon downstream. Analysis indicated normal pre-mRNA splicing producing mRNA transcripts. Truncated RS1 protein was expressed transiently but was degraded rapidly by a proteasomal pathway rather than by nonsense-mediated mRNA decay. Two boys, 1.5 and 5 years of age, had foveal cysts and minimal peripheral schisis, and retained near-normal scotopic b-wave amplitude and normal ERG waveforms. The 5-year-old's ERG was diminished when repeated 3 years later. Four older XLRS relatives 32 to 45 years old had substantial b-wave loss and strongly electronegative ERGs; three had overt macular atrophy. Cross-sectional family analysis showed the b-/a-wave amplitude ratio as inversely related to age in the six males. CONCLUSIONS The c354del1-ins18 mutation caused an RS1-null biochemical phenotype and a progressive clinical phenotype in a 5-year-old boy, whereas the older XLRS relatives had macular atrophy and marked ERG changes. The phenotypic heterogeneity with age by cross-sectional study of this family mutation argues that XLRS disease is not stationary and raises questions regarding factors involved in progression.
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Affiliation(s)
- Camasamudram Vijayasarathy
- Section for Translational Research in Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
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Liu Q, Saveliev A, Pierce EA. The severity of retinal degeneration in Rp1h gene-targeted mice is dependent on genetic background. Invest Ophthalmol Vis Sci 2008; 50:1566-74. [PMID: 19060274 DOI: 10.1167/iovs.08-2776] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The severity of disease in patients with retinitis pigmentosa (RP) can vary significantly, even among patients with the same primary mutations. It is hypothesized that modifier genes play important roles in determining the severity of RP, including the retinitis pigmentosa 1 (RP1) form of disease. To investigate the basis of variation in disease expression for RP1 disease, the authors generated congenic mice with a gene-targeted retinitis pigmentosa 1 homolog (Rp1h) allele (Rp1h(tm1Eap)) on several different genetic backgrounds and analyzed their retinal phenotypes. METHODS The Rp1h(tm1Eap) allele was placed onto the C57BL/6J, DBA1/J, and A/J backgrounds. Retinal function of the resultant congenic mice was evaluated using electroretinographic analyses. Retinal structure and ultrastructure were evaluated using light and electron microscopy. Rp1h protein location was determined with immunofluorescence microscopy. RESULTS Analysis of the retinal phenotype of incipient congenic (N6) B6.129S-Rp1h(+/tm1Eap), DBA.129S(B6)-Rp1h(+/tm1Eap), and A.129S(B6)-Rp1h(+/tm1Eap) mice at 1 year of age showed retinal degeneration only in the A.129S(B6)-Rp1h(+/tm1Eap) mice. Further analyses revealed that the photoreceptors of the fully congenic A.129S(B6)-Rp1h(+/tm1Eap) mice show evidence of degeneration at 6 months of age and are almost completely lost by 18 months of age. In contrast, the photoreceptor cells in the fully congenic B6.129S-Rp1h(+/tm1Eap) mice remain healthy up to 18 months. CONCLUSIONS The severity of the retinal degeneration caused by the Rp1h(tm1Eap) allele is notably dependent on genetic background. The development and characterization of the B6.129S-Rp1h(+/tm1Eap) and A.129S(B6)-Rp1h(+/tm1Eap) congenic mouse lines will facilitate identification of sequence alterations in genes that modify the severity of RP1 disease.
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Affiliation(s)
- Qin Liu
- F. M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA
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Saleheen D, Ali A, Khanum S, Ozair MZ, Zaidi M, Sethi MJ, Khan N, Frossard P. Molecular analysis of the XLRS1 gene in 4 females affected with X-linked juvenile retinoschisis. Can J Ophthalmol 2008; 43:596-9. [DOI: 10.3129/i08-143] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
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