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Kousal B, Hlavata L, Vlaskova H, Dvorakova L, Brichova M, Dubska Z, Langrova H, Vincent AL, Dudakova L, Liskova P. Clinical and Genetic Study of X-Linked Juvenile Retinoschisis in the Czech Population. Genes (Basel) 2021; 12:genes12111816. [PMID: 34828422 PMCID: PMC8623540 DOI: 10.3390/genes12111816] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Revised: 11/10/2021] [Accepted: 11/17/2021] [Indexed: 11/16/2022] Open
Abstract
The aim of this study was to identify RS1 pathogenic variants in Czech patients with X-linked retinoschisis (XLRS) and to describe the associated phenotypes, including natural history, in some cases. Twenty-one affected males from 17 families were included. The coding region of RS1 was directly sequenced and segregation of the identified mutations was performed in available family members. In total, 12 disease-causing variants within RS1 were identified; of these c.20del, c.275G>A, c.[375_379del; 386A>T], c.539C>A and c.575_576insT were novel, all predicted to be null alleles. The c.539C>A mutation occurred de novo. Three patients (aged 8, 11 and 19 years) were misdiagnosed as having intermediate uveitis and treated with systemic steroids. Repeat spectral domain optical coherence tomography examinations in four eyes documented the transition from cystoid macular lesions to macular atrophy in the fourth decade of life. Four individuals were treated with topical dorzolamide and in two of them, complete resolution of the cystic macular lesions bilaterally was achieved, while one patient was noncompliant. Rebound phenomenon after discontinuation of dorzolamide for 7 days was documented in one case. Misdiagnosis of XLRS for uveitis is not uncommon; therefore, identification of disease-causing variants is of considerable benefit to the affected individuals.
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Affiliation(s)
- Bohdan Kousal
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (B.K.); (L.H.); (H.V.); (L.D.); (L.D.)
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (M.B.); (Z.D.)
| | - Lucia Hlavata
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (B.K.); (L.H.); (H.V.); (L.D.); (L.D.)
| | - Hana Vlaskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (B.K.); (L.H.); (H.V.); (L.D.); (L.D.)
| | - Lenka Dvorakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (B.K.); (L.H.); (H.V.); (L.D.); (L.D.)
| | - Michaela Brichova
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (M.B.); (Z.D.)
| | - Zora Dubska
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (M.B.); (Z.D.)
| | - Hana Langrova
- Department of Ophthalmology, Faculty of Medicine in Hradec Kralove, Charles University and University Hospital Hradec Kralove, 500 05 Hradec Kralove, Czech Republic;
| | - Andrea L. Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland 1142, New Zealand;
| | - Lubica Dudakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (B.K.); (L.H.); (H.V.); (L.D.); (L.D.)
| | - Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (B.K.); (L.H.); (H.V.); (L.D.); (L.D.)
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (M.B.); (Z.D.)
- Correspondence: ; Tel.: +420-2-2496-7139
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Stepanova AA, Ivanova EA, Kadyshev VV, Polyakov AV. The Spectrum and Novel Mutations in RS1 Gene in a Russian Cohort of Patients with X-Linked Retinoschisis. RUSS J GENET+ 2021. [DOI: 10.1134/s1022795421070139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Rubinstein Y, Weiner C, Chetrit N, Newman H, Hecht I, Shoshany N, Pras E. Effect of light and diurnal variation on macular thickness in X-linked retinoschisis: a case series. Graefes Arch Clin Exp Ophthalmol 2020; 258:529-536. [PMID: 31897705 DOI: 10.1007/s00417-019-04578-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 12/07/2019] [Accepted: 12/18/2019] [Indexed: 10/25/2022] Open
Abstract
BACKGROUND Diurnal variations in foveal thickness have been reported in several ocular pathologies including X-linked retinoschisis (XLRS), but its underlying mechanism is poorly understood. Rods are active under scotopic conditions with high metabolic demand, and its decrease may have positive effect on metabolic activity and macular thickness. The purpose of this study is to evaluate whether exposure to light and diurnal variation influence macular thickness in XLRS patients. METHODS Five patients with clinical suspicion of XLRS underwent RS1 gene sequencing and optical coherence tomography measurements at three consecutive times: morning following sleep in a dark room, morning following sleep in an illuminated room, and late afternoon following sleep in an illuminated room. Central macular thickness (CMT) was compared between measurements, and molecular analysis was performed. RESULTS Five RS1 mutations were identified: p.Gly140Arg, p.Arg141Cys, p.Gly109Glu, p.Pro193Leu, and p.Arg200His in patients 1-5, respectively. Two patients (4-5) had atrophied macula and were excluded from macular thickness variation analysis. A significant decrease in CMT between morning and afternoon measurements was observed in all patients (1-3: mean: 455.0 ± 32 μm to 342.17 ± 39 μm, 25%). Morning measurements following sleep in an illuminated room show a CMT reduction in all eyes of all patients with a mean reduction of 113 μm (mean: 547.17 ± 105 μm to 455.0 ± 32 μm, 17%). CONCLUSIONS Among XLRS patients, CMT decreased at the afternoon compared to the morning of the same day and may be reduced following sleep in an illuminated room. These results help shed light on the pathophysiologic process underlying intraretinal fluid accumulation involved with the disease.
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Affiliation(s)
- Yair Rubinstein
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel.,Matlow's Ophthalmogenetic Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel
| | - Chen Weiner
- Matlow's Ophthalmogenetic Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel.,Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Noa Chetrit
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel
| | - Hadas Newman
- Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Ophthalmology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel
| | - Idan Hecht
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel. .,Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
| | - Nadav Shoshany
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel.,Matlow's Ophthalmogenetic Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel
| | - Eran Pras
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel.,Matlow's Ophthalmogenetic Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf Harofeh Medical Center), Zerifin, Israel.,Sackler faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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Heymann JB, Vijayasarathy C, Huang RK, Dearborn AD, Sieving PA, Steven AC. Cryo-EM of retinoschisin branched networks suggests an intercellular adhesive scaffold in the retina. J Cell Biol 2019; 218:1027-1038. [PMID: 30630865 PMCID: PMC6400569 DOI: 10.1083/jcb.201806148] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 11/06/2018] [Accepted: 12/07/2018] [Indexed: 12/26/2022] Open
Abstract
Mutations in the essential retinal protein retinoschisin (RS1) cause a form of macular degeneration. Heymann et al. use cryo-EM to show that RS1 assembles into branched networks that may play a stabilizing role in maintaining the integrity of the retina. Mutations in the retinal protein retinoschisin (RS1) cause progressive loss of vision in young males, a form of macular degeneration called X-linked retinoschisis (XLRS). We previously solved the structure of RS1, a 16-mer composed of paired back-to-back octameric rings. Here, we show by cryo–electron microscopy that RS1 16-mers can assemble into extensive branched networks. We classified the different configurations, finding four types of interaction between the RS1 molecules. The predominant configuration is a linear strand with a wavy appearance. Three less frequent types constitute the branch points of the network. In all cases, the “spikes” around the periphery of the double rings are involved in these interactions. In the linear strand, a loop (usually referred to as spike 1) occurs on both sides of the interface between neighboring molecules. Mutations in this loop suppress secretion, indicating the possibility of intracellular higher-order assembly. These observations suggest that branched networks of RS1 may play a stabilizing role in maintaining the integrity of the retina.
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Affiliation(s)
- J Bernard Heymann
- Laboratory for Structural Biology Research, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD
| | - Camasamudram Vijayasarathy
- Section on Translational Research for Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
| | - Rick K Huang
- Cryo-Electron Microscopy Facility, Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA
| | - Altaira D Dearborn
- Laboratory for Structural Biology Research, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD
| | - Paul A Sieving
- Section on Translational Research for Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD.,National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Alasdair C Steven
- Laboratory for Structural Biology Research, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD
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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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Yi J, Li S, Jia X, Xiao X, Wang P, Guo X, Zhang Q. Novel RS1 mutations associated with X-linked juvenile retinoschisis. Int J Mol Med 2012; 29:644-8. [PMID: 22245991 PMCID: PMC3573736 DOI: 10.3892/ijmm.2012.882] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Accepted: 12/15/2011] [Indexed: 11/12/2022] Open
Abstract
To identify mutations in the retinoschisin (RS1) gene in families with X-linked retinoschisis (XLRS). Twenty families with XLRS were enrolled in this study. All six coding exons and adjacent intronic regions of RS1 were amplified by polymerase chain reaction (PCR). The nucleotide sequences of the amplicons were determined by Sanger sequencing. Ten hemizygous mutations in RS1 were detected in patients from 14 of the 20 families. Four of the ten mutations were novel, including c:176G>A (p:Cys59Tyr) in exon 3, c:531T>G (p:Tyr177X), c:607C>G (p:Pro203Ala) and c:668G>A (p:Cys223Tyr) in exon 6. These four novel mutations were not present in 176 normal individuals. The remaining six were recurrent mutations, including c:214G>A (p:Glu72Lys), c:304C>T (p:Arg102Trp), c:436G>A (p:Glu146Lys), c:544C>T (p:Arg182Cys), c:599G>A (p:Arg200His) and c:644A>T (p:Glu215Val). Our study expanded the mutation spectrum of RS1 and enriches our understanding of the molecular basis of XLRS.
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Affiliation(s)
- Junhui Yi
- Department of Ophthalmology, The Third Xiangya Hospital, Central-South University, Changsha 410013, PR China
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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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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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Hayashi T, Omoto S, Takeuchi T, Kozaki K, Ueoka Y, Kitahara K. Four Japanese male patients with juvenile retinoschisis: only three have mutations in the RS1 gene. Am J Ophthalmol 2004; 138:788-98. [PMID: 15531314 DOI: 10.1016/j.ajo.2004.06.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2004] [Indexed: 10/26/2022]
Abstract
PURPOSE To describe the clinical phenotypes of four unrelated Japanese male patients with juvenile retinoschisis and to investigate occurrences of mutations in the RS1 gene. DESIGN Observational case series and experimental study. METHODS Fundus examinations, fluorescein angiography, and single-flash electroretinography (ERG) were carried out. In one patient, optical coherence tomography (OCT) was performed. The coding regions of the RS1 gene that encodes retinoschisin were amplified by polymerase chain reaction (PCR). The PCR products were purified and directly sequenced. RESULTS The four affected patients showed cystoid- or wheel-like foveal changes with a little or no fluorescein leakage and negative b-wave patterns in both eyes. The OCT images of foveal retinoschisis disclosed that splitting occurs in the putative fibers of Henle. In three patients, we identified three different missense mutations (p.S73P, p.Y89C, p.R209C) in the functionally important discoidin domain of the RS1 gene. The p.S73P mutation has not been previously reported. In contrast, no nucleotide substitutions were detected in the fourth patient whose parents were unrelated and asymptomatic. No other member of this family for three generations has had juvenile retinoschisis. CONCLUSION Because serine 73 is conserved in the mouse ortholog and other discoidin proteins, the proline 73 allele is therefore very likely to encode a defective retinoschisin. Although the inheritance pattern is uncertain in the patient without the RS1 mutation, the clinical and ERG findings were indistinguishable from those of patients with RS1 mutations. This finding points to the genetic heterogeneity of juvenile retinoschisis.
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Affiliation(s)
- Takaaki Hayashi
- Department of Ophthalmology, Jikei University School of Medicine, Tokyo, Japan.
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Shinoda K, Ohde H, Ishida S, Inoue M, Oguchi Y, Mashima Y. Novel 473-bp deletion in XLRS1 gene in a Japanese family with X-linked juvenile retinoschisis. Graefes Arch Clin Exp Ophthalmol 2004; 242:561-5. [PMID: 14986011 DOI: 10.1007/s00417-004-0878-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2003] [Revised: 12/18/2003] [Accepted: 01/14/2004] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To present the clinical features of two brothers with molecularly confirmed X-linked juvenile retinoschisis (xlRS) but with non-characteristic electrophysiological findings. METHODS Comprehensive ophthalmological examinations were performed. The electroretinograms (ERGs) were recorded under ISCEV standards, and ERGs elicited by long-duration stimuli were also evaluated. Standard genetic analysis of peripheral blood leukocytes was performed. RESULTS Molecular testing revealed a novel 473-bp deletion including exon 4 in the XLRS1 gene in both siblings. This resulted in a frameshift mutation and a premature termination at codon 78. The scotopic and photopic ERGs were reduced, but the "negative-type" ERG, characteristic of xlRS, was not observed. Flicker ERGs were also highly reduced. Long-duration stimuli elicited ERGs with a complete loss of the b-wave and a preservation of the off-response, i.e., negative-type ERG. The phenotype/genotype relationship was not determined. CONCLUSION The consistency of the ERGs elicited by long-duration stimuli in xlRS patients suggests that this type of stimuli provides responses that are a better indicator for the progression or stage of the disease.
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Affiliation(s)
- Kei Shinoda
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku 160-8582, Tokyo, Japan.
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Simonelli F, Cennamo G, Ziviello C, Testa F, de Crecchio G, Nesti A, Manitto MP, Ciccodicola A, Banfi S, Brancato R, Rinaldi E. Clinical features of X linked juvenile retinoschisis associated with new mutations in the XLRS1 gene in Italian families. Br J Ophthalmol 2003; 87:1130-4. [PMID: 12928282 PMCID: PMC1771850 DOI: 10.1136/bjo.87.9.1130] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AIMS To describe the clinical phenotype of X linked juvenile retinoschisis in eight Italian families with six different mutations in the XLRS1 gene. METHODS Complete ophthalmic examinations, electroretinography and A and B-scan standardised echography were performed in 18 affected males. The coding sequences of the XLRS1 gene were amplified by polymerase chain reaction and directly sequenced on an automated sequencer. RESULTS Six different XLRS1 mutations were identified; two of these mutations Ile81Asn and the Trp122Cys, have not been previously described. The affected males showed an electronegative response to the standard white scotopic stimulus and a prolonged implicit time of the 30 Hz flicker. In the families with Trp112Cys and Trp122Cys mutations we observed a more severe retinoschisis (RS) clinical picture compared with the other genotypes. CONCLUSION The severe RS phenotypes associated with Trp112Cys and to Trp122Cys mutations suggest that these mutations determine a notable alteration in the function of the retinoschisin protein.
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Affiliation(s)
- F Simonelli
- Department of Ophthalmology, Seconda Università di Napoli, Naples, Italy. Telethon Institute of Genetics and Medicine (TIGEM), Italy.
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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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Huopaniemi L, Tyynismaa H, Rantala A, Rosenberg T, Alitalo T. Characterization of two unusual RS1 gene deletions segregating in Danish retinoschisis families. Hum Mutat 2000; 16:307-14. [PMID: 11013441 DOI: 10.1002/1098-1004(200010)16:4<307::aid-humu3>3.0.co;2-l] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Over 100 distinct retinoschisis gene (RS1) mutations, of which approximately 10% are single exon deletions, have been described to date. In this paper we have characterized in detail two dissimilar RS1 gene deletions which are accountable for RS in one-third of Danish patients. First, a 136 kb deletion, spanning from the 5' region of the RS1 gene to intron 3, was identified. Unexpectedly this large deletion abolishes exons of three adjacent genes: serine-threonine phosphatase gene (PPEF-1)/serine-threonine protein phosphatase gene (PP7), retinoschisis gene (RS1), and serine-threonine kinase gene (STK9). We demonstrate that the RS1 and STK9 genes are partly overlapping and the sequences of the PP7 and PPEF-1 genes are identical. This is the first study which reports of retinoschisis patients who also suffer from deletions in genes adjacent to RS1. The 136 kb deletion is also the first gross deletion of the retinoschisis gene deleting three exons. It results from a recombination between two repetitive sequences of the Alu family, one in 5' region of the RS1 gene and the other in RS1 intron 3. The second alteration, the actual Danish RS founder mutation, is a 4.4 kb noncontiguous two-part deletion composed of two deleted 1.5 and 2.9 kb segments, separated by an intact 1.2 kb segment. It extends from the 5' flanking region of the retinoschisis gene to RS intron 1. RS1 gene deletions of this type have not been identified previously. Despite these two unique deletions, which either lead to severely defective transcription or total absence of the retinoschisin and PPEF-1 protein, all the patients have a typical retinoschisis phenotype.
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Affiliation(s)
- L Huopaniemi
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
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