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Chowdhury S, Chermakani P, Baliga G, Anjanamurthy R, Sundaresan P. Genotypic and phenotypic diversity in X-linked retinoschisis: Findings from a South Indian patient cohort. Indian J Ophthalmol 2024; 72:902-911. [PMID: 38317323 PMCID: PMC11232871 DOI: 10.4103/ijo.ijo_2525_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/12/2023] [Accepted: 12/13/2023] [Indexed: 02/07/2024] Open
Abstract
PURPOSE Retinoschisis is a distinctive condition characterized by intraretinal layer clefts, primarily associated with X-linked recessive inheritance due to RS1 gene mutations. This study aims to uncover the RS1 mutation spectrum in a cohort of 22 X-linked retinoschisis cases from South India and emphasizes the genotypic and phenotypic associations within patients harboring only RS1 mutations. METHODS A total of 22 probands were suspected of having X-linked retinoschisis. All study subjects underwent ophthalmic investigations, including assessments of visual acuity, fundus examination, optical coherence tomography (OCT), and electroretinogram (ERG). RS1 gene screening was conducted using Sanger sequencing, and the pathogenicity of the variants was assessed through Sorting Intolerant from Tolerant (SIFT) and PolyPhen-2 in silico tools. RESULTS The study found that the probands had an average visual acuity of 0.79 ± 0.39 log of minimum angle of resolution (logMAR), ranging from 0.17 to 1.77. During fundus examination, the probands exhibited a characteristic spoke wheel-like pattern in the macular region. Furthermore, OCT analysis revealed distinct alterations in the inner retinal microstructure, and ERG results consistently showed a reduction in b-wave amplitude. Eventually, Sanger sequencing results showed hemizygous mutations in the RS1 gene in only 12 probands, including a novel missense mutation in the RS1 gene's signal sequence. CONCLUSION This study provides valuable insights into the spectrum of RS1 mutations in X-linked retinoschisis probands from South India. It reveals distinct genotypic-phenotypic associations and highlights the clinical manifestations associated with the disease pathogenesis.
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Affiliation(s)
- Susmita Chowdhury
- Department of Molecular Genetics, Aravind Medical Research Foundation, Madurai, Tamil Nadu, India
- Department of Molecular Biology, Aravind Medical Research Foundation - Affiliated to Alagappa University, Karaikudi, Tamil Nadu, India
| | - Prakash Chermakani
- Department of Molecular Genetics, Aravind Medical Research Foundation, Madurai, Tamil Nadu, India
- Department of Molecular Biology, Aravind Medical Research Foundation - Affiliated to Alagappa University, Karaikudi, Tamil Nadu, India
| | - Girish Baliga
- Department of Retina-Vitreous Services, Madurai, Tamil Nadu, India
| | - Rupa Anjanamurthy
- Paediatric Ophthalmology and Adult Strabismus Services, Aravind Eye Hospital, Madurai, Tamil Nadu, India
| | - Periasamy Sundaresan
- Department of Molecular Genetics, Aravind Medical Research Foundation, Madurai, Tamil Nadu, India
- Department of Molecular Biology, Aravind Medical Research Foundation - Affiliated to Alagappa University, Karaikudi, Tamil Nadu, India
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van der Veen I, Heredero Berzal A, Koster C, ten Asbroek ALMA, Bergen AA, Boon CJF. The Road towards Gene Therapy for X-Linked Juvenile Retinoschisis: A Systematic Review of Preclinical Gene Therapy in Cell-Based and Rodent Models of XLRS. Int J Mol Sci 2024; 25:1267. [PMID: 38279267 PMCID: PMC10816913 DOI: 10.3390/ijms25021267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 01/12/2024] [Accepted: 01/17/2024] [Indexed: 01/28/2024] Open
Abstract
X-linked juvenile retinoschisis (XLRS) is an early-onset progressive inherited retinopathy affecting males. It is characterized by abnormalities in the macula, with formation of cystoid retinal cavities, frequently accompanied by splitting of the retinal layers, impaired synaptic transmission of visual signals, and associated loss of visual acuity. XLRS is caused by loss-of-function mutations in the retinoschisin gene located on the X chromosome (RS1, MIM 30083). While proof-of-concept studies for gene augmentation therapy have been promising in in vitro and rodent models, clinical trials in XLRS patients have not been successful thus far. We performed a systematic literature investigation using search strings related to XLRS and gene therapy in in vivo and in vitro models. Three rounds of screening (title/abstract, full text and qualitative) were performed by two independent reviewers until consensus was reached. Characteristics related to study design and intervention were extracted from all studies. Results were divided into studies using (1) viral and (2) non-viral therapies. All in vivo rodent studies that used viral vectors were assessed for quality and risk of bias using the SYRCLE's risk-of-bias tool. Studies using alternative and non-viral delivery techniques, either in vivo or in vitro, were extracted and reviewed qualitatively, given the diverse and dispersed nature of the information. For in-depth analysis of in vivo studies using viral vectors, outcome data for optical coherence tomography (OCT), immunohistopathology and electroretinography (ERG) were extracted. Meta-analyses were performed on the effect of recombinant adeno-associated viral vector (AAV)-mediated gene augmentation therapies on a- and b-wave amplitude as well as the ratio between b- and a-wave amplitudes (b/a-ratio) extracted from ERG data. Subgroup analyses and meta-regression were performed for model, dose, age at injection, follow-up time point and delivery method. Between-study heterogeneity was assessed with a Chi-square test of homogeneity (I2). We identified 25 studies that target RS1 and met our search string. A total of 19 of these studies reported rodent viral methods in vivo. Six of the 25 studies used non-viral or alternative delivery methods, either in vitro or in vivo. Of these, five studies described non-viral methods and one study described an alternative delivery method. The 19 aforementioned in vivo studies were assessed for risk of bias and quality assessments and showed inconsistency in reporting. This resulted in an unclear risk of bias in most included studies. All 19 studies used AAVs to deliver intact human or murine RS1 in rodent models for XLRS. Meta-analyses of a-wave amplitude, b-wave amplitude, and b/a-ratio showed that, overall, AAV-mediated gene augmentation therapy significantly ameliorated the disease phenotype on these parameters. Subgroup analyses and meta-regression showed significant correlations between b-wave amplitude effect size and dose, although between-study heterogeneity was high. This systematic review reiterates the high potential for gene therapy in XLRS, while highlighting the importance of careful preclinical study design and reporting. The establishment of a systematic approach in these studies is essential to effectively translate this knowledge into novel and improved treatment alternatives.
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Affiliation(s)
- Isa van der Veen
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Andrea Heredero Berzal
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Céline Koster
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Anneloor L. M. A. ten Asbroek
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Arthur A. Bergen
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Human Genetics, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands;
| | - Camiel J. F. Boon
- Department of Ophthalmology, Amsterdam UMC, University of Amsterdam, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands; (I.v.d.V.); (A.H.B.); (C.K.); (A.A.B.)
- Department of Ophthalmology, Leiden University Medical Center, Leiden University, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
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Ambrosio L, Akula JD, Harman JC, Arellano IA, Fulton AB. Do the retinal abnormalities in X-linked juvenile retinoschisis include impaired phototransduction? Exp Eye Res 2023; 234:109591. [PMID: 37481224 DOI: 10.1016/j.exer.2023.109591] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 07/16/2023] [Indexed: 07/24/2023]
Abstract
X-linked juvenile retinoschisis (XLRS), a hereditary retinal disorder primarily affecting males, is characterized by the formation of cystic spaces between the outer plexiform layer and outer nuclear layer of the retina. Mutations in the RS1 gene, which encodes the extracellular binding protein retinoschisin, are responsible for XLRS pathogenesis. While the role of retinoschisin in maintaining retinal integrity is well established, there is growing evidence suggesting compromised photoreceptor function in XLRS. To investigate the molecular pathways affected by RS1 deficiency, particularly in phototransduction, we performed electroretinographic (ERG) and proteomic analyses on retinae from Rs1 knockout mice, a model of human XLRS. The Rs1 knockout mice had reduced ERG a-wave amplitudes. Correspondingly, differential expression analysis revealed downregulation of proteins crucial for phototransduction, with Ingenuity Pathway Analysis (IPA) highlighting "phototransduction" as the most significantly downregulated biological theme. Compensatory mechanisms were also observed in the IPA, including upregulation of synaptic remodeling, inflammation, cell adhesion, and G-protein signaling. These findings strongly implicate an underrecognized role of photoreceptor dysfunction in XLRS pathology. We speculate that entrapment of mutant retinoschisin protein within photoreceptor inner segments as well as disrupted reciprocal regulation between L-type voltage-gated calcium channels and retinoschisin contribute to the dysfunction in photoreceptors.
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Affiliation(s)
- Lucia Ambrosio
- Department of Neuroscience, Reproductive and Odontostomatological Sciences, University of Naples Federico II, Naples, Italy; Department of Public Health, University of Naples Federico II, Naples, Italy; Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - James D Akula
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
| | - Jarrod C Harman
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Harvard Medical School, Boston, MA, USA; Department of Pharmacology and Bioanalytics, EyeCRO LLC, Ann Arbor, MI, USA
| | - Ivana A Arellano
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA
| | - Anne B Fulton
- Department of Ophthalmology, Boston Children's Hospital, Boston, MA, USA; Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
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Feathers KL, Jia L, Khan NW, Smith AJ, Ma JX, Ali RR, Thompson DA. Gene Supplementation in Mice Heterozygous for the D477G RPE65 Variant Implicated in Autosomal Dominant Retinitis Pigmentosa. Hum Gene Ther 2023; 34:639-648. [PMID: 37014074 PMCID: PMC10354729 DOI: 10.1089/hum.2022.240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 03/20/2023] [Indexed: 04/05/2023] Open
Abstract
The use of AAV-RPE65 vectors for gene supplementation has achieved spectacular success as a treatment for individuals with autosomal recessive retinal disease caused by biallelic mutations in the visual cycle gene RPE65. However, the efficacy of this approach in treating autosomal dominant retinitis pigmentosa (adRP) associated with a monoallelic mutation encoding a rare D477G RPE65 variant has not been studied. Although lacking a severe phenotype, we now find that knock-in mice heterozygous for D477G RPE65 (D477G KI mice) can be used to evaluate outcomes of AAV-RPE65 gene supplementation. Total RPE65 protein levels, which are decreased in heterozygous D477G KI mice, were doubled following subretinal delivery of rAAV2/5.hRPE65p.hRPE65. In addition, rates of recovery of the chromophore 11-cis retinal after bleaching were significantly increased in eyes that received AAV-RPE65, consistent with increased RPE65 isomerase activity. While dark-adapted chromophore levels and a-wave amplitudes were not affected, b-wave recovery rates were modestly improved. The present findings establish that gene supplementation enhances 11-cis retinal synthesis in heterozygous D477G KI mice and complement previous studies showing that chromophore therapy results in improved vision in individuals with adRP associated with D477G RPE65.
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Affiliation(s)
- Kecia L. Feathers
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Lin Jia
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Naheed W. Khan
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alexander J. Smith
- Centre for Stem Cells & Regenerative Medicine, King's College London, London, United Kingdom
| | - Jian-Xing Ma
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Robin R. Ali
- Centre for Stem Cells & Regenerative Medicine, King's College London, London, United Kingdom
| | - Debra A. Thompson
- Department of Biological Chemistry, University of Michigan Medical School, Ann Arbor, Michigan, USA
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Hathibelagal AR, Bhutia P, Das M, Babu H, Jalali S, Takkar B, Paremeswarappa DC, Ballae Ganeshrao S. Tablet-based 'ON/OFF' pathway test can distinguish between rod- and cone-dominated diseases. Ophthalmic Physiol Opt 2023; 43:231-238. [PMID: 36416095 DOI: 10.1111/opo.13072] [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: 06/28/2022] [Revised: 11/07/2022] [Accepted: 11/08/2022] [Indexed: 11/23/2022]
Abstract
INTRODUCTION The photopic ON pathway defect is associated with nocturnal vision loss. However, the measurement of ON function to detect a rod-dominated disease (rods affected more than cones) has not been explored. We evaluated whether the psychophysical evaluation of ON/OFF pathways can be used to distinguish cone-dominated from rod-dominated diseases. METHODS Thirty-seven patients with inherited retinal diseases were tested using the 'EyeSpeed' [iOS application] on an iPad. The test displayed a random number (1-3) of light or dark targets on a black-and-white noise background. Participants responded on a touch screen indicating the correct number of targets displayed. The outcome variables-reaction time, accuracy and performance index (speed [1/reaction time] * accuracy) to both light and dark targets were assessed for diagnostic ability using standard receiver-operating characteristic (ROC) analysis. RESULTS Mean ± standard deviation age and visual acuity for the cone- and rod-dominated groups were 25.15 ± 11.74 years, 0.80 ± 0.25 logMAR and 28.3 ± 14.29 years, 0.48 ± 0.26 logMAR, respectively. The median reaction time to light targets in rod-dominated disease [interquartile range] was 5.28 s [3.17], significantly greater than for patients with cone-dominated disease (2.07 s [0.93]; Mann-Whitney U test, p < 0.001). Amongst all of the outcome variables evaluated, the reaction time to light targets (criterion of ≥2.98 s) exhibited the highest area under the ROC curve (area = 0.89 ± 0.11; p < 0.001), with a sensitivity and specificity of 82.4% and 85% respectively. CONCLUSIONS Reaction time to light targets using the ON/OFF pathway paradigm is a valid marker to differentiate between rod- and cone-dominated retinal dystrophies. ON pathway function measured using a tablet-based test could act as a supplemental test in the diagnosis of challenging photoreceptor-specific inherited retinal diseases.
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Affiliation(s)
- Amithavikram R Hathibelagal
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, India.,Professor Brien Holden Eye Research Center, L V Prasad Eye Institute, Hyderabad, India
| | - Phuntsok Bhutia
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, India.,Professor Brien Holden Eye Research Center, L V Prasad Eye Institute, Hyderabad, India
| | - Mritunjoy Das
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, India.,Professor Brien Holden Eye Research Center, L V Prasad Eye Institute, Hyderabad, India
| | - Helna Babu
- Brien Holden Institute of Optometry and Vision Sciences, L V Prasad Eye Institute, Hyderabad, India.,Professor Brien Holden Eye Research Center, L V Prasad Eye Institute, Hyderabad, India
| | - Subhadra Jalali
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, Anant Bajaj Retina Institute, L V Prasad Eye Institute, Hyderabad, India.,Jasti V Ramanamma Children's Eye Care Centre, Child Sight Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Brijesh Takkar
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, Anant Bajaj Retina Institute, L V Prasad Eye Institute, Hyderabad, India.,Indian Health Outcomes, Public Health, and Economics Research (IHOPE) Centre, L V Prasad Eye Institute, Hyderabad, India
| | - Deepika C Paremeswarappa
- Srimati Kanuri Santhamma Centre for Vitreoretinal Diseases, Anant Bajaj Retina Institute, L V Prasad Eye Institute, Hyderabad, India
| | - Shonraj Ballae Ganeshrao
- Department of Optometry, Manipal College of Health Professions, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India
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Chiang TK, Yu M. Electrophysiological Evaluation of Macular Dystrophies. J Clin Med 2023; 12:jcm12041430. [PMID: 36835965 PMCID: PMC9962076 DOI: 10.3390/jcm12041430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 02/15/2023] Open
Abstract
Macular dystrophies are a heterogeneous group of genetic disorders that often severely threatens the bilateral central vision of the affected patient. While advances in molecular genetics have been instrumental in the understanding and diagnosis of these disorders, there remains significant phenotypical variation among patients within any particular subset of macular dystrophies. Electrophysiological testing remains a vital tool not only to characterize vision loss for differential diagnosis but also to understand the pathophysiology of these disorders and to monitor the treatment effect, potentially leading to therapeutic advances. This review summarizes the application of electrophysiological testing in macular dystrophies, including Stargardt disease, bestrophinopathies, X-linked retinoschisis, Sorsby fundus dystrophy, Doyne honeycomb retina dystrophy, autosomal dominant drusen, occult macular dystrophy, North Carolina macular dystrophy, pattern dystrophy, and central areolar choroidal dystrophy.
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Wang XF, Chen FF, Zhou X, Cheng XX, Xie ZG. A novel mutation in RS1 and clinical manifestations in a Chinese twin family with congenital retinoschisis. Front Genet 2022; 13:993157. [PMID: 36212125 PMCID: PMC9538544 DOI: 10.3389/fgene.2022.993157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Accepted: 08/22/2022] [Indexed: 11/13/2022] Open
Abstract
Purpose: We aim to analyze the clinical and genetic features in a Chinese family with congenital retinoschisis by whole-exome sequencing and comprehensive clinical examination.Methods: Six members were recruited from a Chinese family. Three of them were diagnosed as congenital retinoschisis, including two twin siblings. All subjects received a full eye examination. Whole-exome sequencing (WES) and Sanger sequencing were performed on two twin probands and all participants, respectively.Results: A novel splice site mutation RS1.c.53-1G>A was identified in a Chinese congenital retinoschisis family. The mean onset age was 16.7 ± 2.4 years old. The average BCVA in patients was 0.37 ± 0.05. A typical spoke-wheel pattern was observed in all affected eyes. OCT examination results showed fovea schisis and schisis cavities were located in the inner nuclear layer in 100% eyes (6/6). ERG b/a ratio was decreased markedly, but was still more than 1 in the four eyes that were available.Conclusion: The present study discovered a new pathogenic splice cite variant of RS1 in congenital retinoschisis, which expands the mutational spectrum. In contrast to previous research, the phenotype of patients with the same mutation within one family was highly similar. Early molecular testing is crucial for early diagnosis, clinical management, and genetic counseling of patients with congenital retinoschisis.
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Affiliation(s)
- Xiao-Fang Wang
- Department of Ophthalmology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Fei-Fei Chen
- Department of Ophthalmology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Xin Zhou
- Department of Ophthalmology, The First People’s Hospital of Kunshan Affiliated with Jiangsu University, Suzhou, China
| | - Xin-Xuan Cheng
- Department of Ophthalmology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Zheng-Gao Xie
- Department of Ophthalmology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
- *Correspondence: Zheng-Gao Xie,
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Yan W, Wang Y, Ye Q, Chen X, Chen Y, Jiang C, Chen M. The electrophysiological features of X-linked juvenile retinoschisis in a young male: a case report. J Int Med Res 2022; 50:3000605211039571. [PMID: 34994217 PMCID: PMC8743956 DOI: 10.1177/03000605211039571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
This case report describes the detailed electrophysiological features and the corresponding relationship with the structural changes in a case of X-linked juvenile retinoschisis (XLRS). A 25-year-old male presented with a history of several years of decreased visual acuity in both eyes. The best corrected visual acuity was 20/200 in oculus dexter (OD) and 20/80 in oculus sinister. Retinoschisis was found in the macula by optical coherence tomography, which was more severe in OD. Electroretinogram revealed a similar electronegative waveform in both eyes. Visual evoked potential detected a reduced amplitude and delayed phase in P100-wave, which was worse in OD. The patient was diagnosed as XLRS and advised to undergo continuous medical observation. He was followed up for the next year, with no significant change in retinal function and structure being observed. These current findings suggest that electrophysiology permits the detailed analysis of the clinical picture of XLRS and helps to gain a deeper understanding of the pathogenesis.
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Affiliation(s)
- Weiming Yan
- Department of Ophthalmology, The 900th Hospital of Joint Logistic Support Force, PLA (Clinical Medical College of Fujian Medical University, Dongfang Hospital Affiliated to Xiamen University), Fuzhou Province, China
| | - Yunpeng Wang
- Department of Ophthalmology, The 900th Hospital of Joint Logistic Support Force, PLA (Clinical Medical College of Fujian Medical University, Dongfang Hospital Affiliated to Xiamen University), Fuzhou Province, China
| | - Qian Ye
- Department of Ophthalmology, The 900th Hospital of Joint Logistic Support Force, PLA (Clinical Medical College of Fujian Medical University, Dongfang Hospital Affiliated to Xiamen University), Fuzhou Province, China
| | - Xiaohong Chen
- Department of Ophthalmology, The 900th Hospital of Joint Logistic Support Force, PLA (Clinical Medical College of Fujian Medical University, Dongfang Hospital Affiliated to Xiamen University), Fuzhou Province, China
| | - Yanjin Chen
- Department of Ophthalmology, The 900th Hospital of Joint Logistic Support Force, PLA (Clinical Medical College of Fujian Medical University, Dongfang Hospital Affiliated to Xiamen University), Fuzhou Province, China
| | - Chuan Jiang
- Department of Ophthalmology, The 900th Hospital of Joint Logistic Support Force, PLA (Clinical Medical College of Fujian Medical University, Dongfang Hospital Affiliated to Xiamen University), Fuzhou Province, China
| | - Meizhu Chen
- Department of Ophthalmology, The 900th Hospital of Joint Logistic Support Force, PLA (Clinical Medical College of Fujian Medical University, Dongfang Hospital Affiliated to Xiamen University), Fuzhou Province, China
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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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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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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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12
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Ambrosio L, Williams JS, Gutierrez A, Swanson EA, Munro RJ, Ferguson RD, Fulton AB, Akula JD. Carbonic anhydrase inhibition in X-linked retinoschisis: An eye on the photoreceptors. Exp Eye Res 2020; 202:108344. [PMID: 33186570 DOI: 10.1016/j.exer.2020.108344] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 09/01/2020] [Accepted: 10/26/2020] [Indexed: 12/28/2022]
Abstract
The retinoschisin protein is encoded on the short arm of the X-chromosome by RS1, is expressed abundantly in photoreceptor inner segments and in bipolar cells, and is secreted as an octamer that maintains the structural integrity of the retina. Mutations in RS1 lead to X-linked retinoschisis (XLRS), a disease characterized by the formation of cystic spaces between boys' retinal layers that frequently present in ophthalmoscopy as a "spoke-wheel" pattern on their maculae and by progressively worsening visual acuity (VA). There is no proven therapy for XLRS, but there is mixed evidence that carbonic anhydrase inhibitors (CAIs) produce multiple beneficial effects, including improved VA and decreased volume of cystic spaces. Consequently, linear mixed-effects (LME) models were used to evaluate the effects of CAI therapy on VA and central retinal thickness (CRT, a proxy for cystic cavity volume) in a review of 19 patients' records. The mechanism of action of action of CAIs is unclear but, given that misplaced retinoschisin might accumulate in the photoreceptors, it is possible-perhaps even likely-that CAIs act to benefit the function of photoreceptors and the neighboring retinal pigment epithelium by acidification of the extracellular milieu; patients on CAIs have among the most robust photoreceptor responses. Therefore, a small subset of five subjects were recruited for imaging on a custom multimodal adaptive optics retinal imager for inspection of their parafoveal cone photoreceptors. Those cones that were visible, which numbered far fewer than in controls, were enlarged, consistent with the retinoschisin accumulation hypothesis. Results of the LME modeling found that there is an initial benefit to both VA and CRT in CAI therapy, but these wane, in both cases, after roughly two years. That said, even a short beneficial effect of CAIs on the volume of the cystic spaces may give CAI therapy an important role as pretreatment before (or immediately following) administration of gene therapy.
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Affiliation(s)
- Lucia Ambrosio
- Ophthalmology, Boston Children's Hospital, USA; Ophthalmology, Harvard Medical School, USA
| | - Jacqueline S Williams
- Ophthalmology, Boston Children's Hospital, USA; Biology, Northeastern University, USA
| | - Alfredo Gutierrez
- Ophthalmology, Boston Children's Hospital, USA; Community Health, Tufts University, USA
| | | | | | | | - Anne B Fulton
- Ophthalmology, Boston Children's Hospital, USA; Ophthalmology, Harvard Medical School, USA
| | - James D Akula
- Ophthalmology, Boston Children's Hospital, USA; Ophthalmology, Harvard Medical School, USA; Psychology, Northeastern University, USA.
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C Parameswarappa D, Belenje A, Rani PK. Multimodal imaging of bilateral macular hole in X-linked retinoschisis. BMJ Case Rep 2020; 13:13/9/e238354. [DOI: 10.1136/bcr-2020-238354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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McAnany JJ, Park JC, Fishman GA, Collison FT. Full-Field Electroretinography, Pupillometry, and Luminance Thresholds in X-Linked Retinoschisis. Invest Ophthalmol Vis Sci 2020; 61:53. [PMID: 32579680 PMCID: PMC7416904 DOI: 10.1167/iovs.61.6.53] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose To evaluate the nature and extent of functional abnormality in X-linked retinoschisis (XLRS) by comparing three dark-adapted, full-field measures: the electroretinogram (ERG), pupillary light reflex (PLR), and luminance threshold. Methods ERGs, PLRs (pupil constriction due to light stimulation), and luminance thresholds were measured from seven XLRS subjects and from 10 normally sighted, age-similar controls. ERGs and PLRs were obtained for a range of flash strengths, and these data were fit with Naka–Rushton functions to derive the maximum saturated b-wave (Vmax) and PLR (Pmax) amplitudes. Additionally, semi-saturation constants were obtained for the b-wave (σ) and PLR (s). Values of 1/σ and 1/s provide sensitivity measures. Full-field, dark-adapted luminance thresholds were measured using 465-nm and 642-nm flash stimuli. Results Vmax and 1/σ were significantly reduced in XLRS compared to the controls (both t ≥ 5.33, P < 0.001). In comparison, Pmax was normal in the XLRS subjects (t = 1.39, P = 0.19), but 1/s was reduced (t = 7.84, P < 0.001). Luminance thresholds for the control and XLRS groups did not differ significantly (F = 3.57, P = 0.08). Comparisons among measures indicated that pupil sensitivity was correlated with luminance threshold for the long- and short-wavelength stimuli (both, r ≥ 0.77, P ≤ 0.04). Correlations among all other measures were not statistically significant. Conclusions The results indicate that the presumed bipolar cell dysfunction in XLRS, indicated by b-wave abnormalities, has complex downstream effects: Dark-adapted luminance threshold and maximum pupil responses are not significantly affected, but pupil sensitivity is reduced.
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Ambrosio L, Hansen RM, Kimia R, Fulton AB. Retinal Function in X-Linked Juvenile Retinoschisis. Invest Ophthalmol Vis Sci 2020; 60:4872-4881. [PMID: 31747688 DOI: 10.1167/iovs.19-27897] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To assess retinal function in young patients with X-linked juvenile retinoschisis (XLRS), a disorder that is known to alter ERG postreceptor retinal components and also possibly photoreceptor components. Methods ERG responses to full-field stimuli were recorded under scotopic and photopic conditions in 12 XLRS patients aged 1 to 15 (median 8) years. A- and b-wave amplitudes and implicit times were examined over a range of stimulus intensities. Rod and cone photoreceptor (SROD, RROD, SCONE, RCONE) and rod-driven postreceptor (log σ, VMAX) response parameters were calculated from the a- and b-waves. Data from XLRS patients were evaluated for significant change with age. Results A- and b-wave amplitudes were smaller in XLRS patients compared with controls under both scotopic and photopic conditions. Saturated photoresponse amplitude (RROD), postreceptor b-wave (log σ), and saturated b-wave amplitude (VMAX) were significantly lower in XLRS patients than in controls; SROD did not differ between the two groups. SCONE and RCONE values were normal. In XLRS patients, neither a- and b-wave amplitudes nor calculated parameters (SROD, RROD, log σ, VMAX,SCONE, and RCONE) changed with age. Conclusions In these young XLRS patients, RROD and a-wave amplitudes were significantly smaller than in controls. Thus, in addition to XLRS causing postreceptor dysfunction, an effect of XLRS on rod photoreceptors cannot be ignored.
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Affiliation(s)
- Lucia Ambrosio
- Department of Ophthalmology, Boston Children's Hospital & Harvard Medical School, Boston, Massachusetts, United States
| | - Ronald M Hansen
- Department of Ophthalmology, Boston Children's Hospital & Harvard Medical School, Boston, Massachusetts, United States
| | - Rotem Kimia
- Department of Ophthalmology, Boston Children's Hospital & Harvard Medical School, Boston, Massachusetts, United States
| | - Anne B Fulton
- Department of Ophthalmology, Boston Children's Hospital & Harvard Medical School, Boston, Massachusetts, United States
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Identification of the retinoschisin-binding site on the retinal Na/K-ATPase. PLoS One 2019; 14:e0216320. [PMID: 31048931 PMCID: PMC6497308 DOI: 10.1371/journal.pone.0216320] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 04/19/2019] [Indexed: 01/11/2023] Open
Abstract
X-linked juvenile retinoschisis (XLRS) is a hereditary retinal dystrophy, caused by mutations in the RS1 gene which encodes the secreted protein retinoschisin. In recent years, several molecules have been proposed to interact with retinoschisin, including the retinal Na/K-ATPase, L-voltage gated Ca2+ channels, and specific sugars. We recently showed that the retinal Na/K-ATPase consisting of subunits ATP1A3 and ATP1B2 is essential for anchoring retinoschisin to plasma membranes and identified the glycosylated ATP1B2 subunit as the direct interaction partner for retinoschisin. We now aimed to precisely map the retinoschisin binding domain(s) in ATP1B2. In general, retinoschisin binding was not affected after selective elimination of individual glycosylation sites via site-directed mutagenesis as well as after full enzymatic deglycosylation of ATP1B2. Applying the interface prediction tool PresCont, two putative protein-protein interaction patches (“patch I” and “patch II”) consisting each of four hydrophobic amino acid stretches on the ATP1B2 surface were identified. These were consecutively altered by site-directed mutagenesis. Functional assays with the ATP1B2 patch mutants identified patch II and, specifically, the associated amino acid at position 240 (harboring a threonine in ATP1B2) as crucial for retinoschisin binding to ATP1B2. These and previous results led us to suggest an induced-fit binding mechanism for the interaction between retinoschisin and the Na/K-ATPase, which is dependent on threonine 240 in ATP1B2 allowing the accommodation of hyperflexible retinoschisin spikes by the associated protein-protein interaction patch on ATP1B2.
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A case of X-linked retinoschisis with atypical fundus appearance. Doc Ophthalmol 2019; 139:75-81. [PMID: 31006083 DOI: 10.1007/s10633-019-09698-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 04/10/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE Mutations in the RS1 gene are known to cause retinoschisis, an X-linked hereditary retinal degeneration. Here, we present a case of atypical retinoschisis with clinical findings of retinoschisis and retinitis pigmentosa. METHODS This report is an observational case report. The detailed ophthalmological examinations included visual field determination, multimodal imaging and electrophysiological recordings. Targeted next-generation sequencing of a retinal disease gene panel was performed. RESULTS The 55-year-old male, highly hyperopic patient, presented with a best-corrected Snellen visual acuity of 20/100 in the right eye and 20/400 in the left eye. In the kinetic visual field, there was a superior scotoma, as well as a ring scotoma in the inferior hemisphere in the right eye and a concentric visual field constriction to 10° in the left eye. Funduscopy revealed marked pigmentary changes (i.e. bone spicules) in the mid-periphery bilaterally and symmetrically, as well as two small intra-retinal haemorrhages in the left eye. Full-field electroretinography recordings showed extinguished rod and cone responses. Diagnostic-genetic testing revealed a hemizygous missense mutation in the RS1 gene (c.305G > A; p.Arg102Gln) was identified. CONCLUSION We present a case of atypical retinoschisis with clinical findings of retinitis pigmentosa.
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Cukras CA, Huryn LA, Jeffrey BG, Turriff A, Sieving PA. Analysis of Anatomic and Functional Measures in X-Linked Retinoschisis. Invest Ophthalmol Vis Sci 2019; 59:2841-2847. [PMID: 30025115 PMCID: PMC5987578 DOI: 10.1167/iovs.17-23297] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To examine the symmetry of structural and functional parameters between eyes in patients with X-linked retinoschisis (XLRS), as well as changes in visual acuity and electrophysiology over time. Methods This is a single-center observational study of 120 males with XLRS who were evaluated at the National Eye Institute. Examinations included best-corrected visual acuity for all participants, as well as ERG recording and optical coherence tomography (OCT) on a subset of participants. Statistical analyses were performed using nonparametric Spearman correlations and linear regression. Results Our analyses demonstrated a statistically significant correlation of structural and functional measures between the two eyes of XLRS patients for all parameters. OCT central macular thickness (n = 78; Spearman r = 0.83, P < 0.0001) and ERG b/a ratio (n = 78; Spearman r = 0.82, P < 0.0001) were the most strongly correlated between a participant's eyes, whereas visual acuity was less strongly correlated (n = 120; Spearman r = 0.47, P < 0.0001). Stability of visual acuity was observed with an average change of less than one letter (n = 74; OD −0.66 and OS −0.70 letters) in a mean follow-up time of 6.8 years. There was no statistically significant change in the ERG b/a ratio within eyes over time. Conclusions Although a broad spectrum of clinical phenotypes is observed across individuals with XLRS, our study demonstrates a significant correlation of structural and functional findings between the two eyes and stability of measures of acuity and ERG parameters over time. These results highlight the utility of the fellow eye as a useful reference for monocular interventional trials.
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Affiliation(s)
- Catherine A Cukras
- Division of Epidemiology and Clinical Research, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States.,Ocular Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Laryssa A Huryn
- Ocular Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Brett G Jeffrey
- Ocular Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Amy Turriff
- Ocular Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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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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Plössl K, Schmid V, Straub K, Schmid C, Ammon M, Merkl R, Weber BHF, Friedrich U. Pathomechanism of mutated and secreted retinoschisin in X-linked juvenile retinoschisis. Exp Eye Res 2018; 177:23-34. [PMID: 30040949 DOI: 10.1016/j.exer.2018.07.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 07/20/2018] [Accepted: 07/20/2018] [Indexed: 01/08/2023]
Abstract
Mutations in the RS1 gene encoding retinoschisin cause X-linked juvenile retinoschisis (XLRS), a hereditary retinal dystrophy in males. While most of the XLRS associated mutations strongly interfere with cellular secretion, this is not true for mutants RS1-F108C, -R141G, -R141H, -R182C, -H207Q and -R209H. Native retinoschisin builds double-octamers and binds to retinal membranes, interacting with the retinal Na/K-ATPase. Functionally, it regulates MAP kinase signaling and Na/K-ATPase localization, and hampers photoreceptor degeneration. In this study, we investigated the capacity of the retinoschisin mutants still secreted extracellularly to fulfil these tasks. We addressed secretion and oligomerization of the heterologously expressed mutants as well as their binding to recombinant retinal Na/K-ATPases and murine retinoschisin-deficient (Rs1h-/Y) retinal and non-retinal explants. This has refined the categorization of secreted retinoschisin mutants: (i) no octamerization, unspecific membrane binding (RS1-F108C and -R182C), (ii) double-octamerization but no membrane binding (RS1-R141H), and (iii) double-octamerization and unspecific membrane binding (RS1-R141G, -H207Q, and -R209H). Notably, selected mutants of all categories (RS1-F108C, -R141H, and -R209H) failed to regulate retinal MAP kinase signaling and Na/K-ATPase localization in Rs1h-/Y retinal explants, and could not attenuate photoreceptor degeneration. Bioinformatic modeling of the secreted mutants depicted prominent alterations in the spatial and temporal conformation of a substructure called "spike 3" and its vicinity, implying a crucial role of this substructure for binding capacity and specificity. Taken together, our data point to a pathomechanism for secreted retinoschisin mutants, specifically to disturbances of the retinoschisin interface accompanied by unphysiological membrane interactions and impaired regulatory functions.
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Affiliation(s)
- Karolina Plössl
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Verena Schmid
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Kristina Straub
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
| | - Carina Schmid
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Mirjam Ammon
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Rainer Merkl
- Institute of Biophysics and Physical Biochemistry, University of Regensburg, Universitätsstraße 31, 93040 Regensburg, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany
| | - Ulrike Friedrich
- Institute of Human Genetics, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany.
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Abstract
The International Society for Clinical Electrophysiology of Vision (ISCEV) standard for full-field electroretinography (ERG) describes a minimum procedure, but encourages more extensive testing. This ISCEV extended protocol describes an extension to the ERG standard, namely the photopic On-Off ERG, and outlines common clinical applications. A light stimulus duration of 150-200 ms is used in the presence of a rod-suppressing background to elicit cone-driven On- and Off-system ERG components. The On-response occurs after the stimulus onset and has a negative a-wave and positive b-wave. The Off d-wave is a positive component evoked by stimulus offset. Common diagnoses that may benefit from additional photopic On-Off ERG testing include retinal dystrophies and retinal disorders that cause dysfunction at a level that is post-phototransduction or post-receptoral. On-Off ERGs assess the relative involvement of On- and Off-systems and may be of use in the diagnosis of disorders such as complete and incomplete congenital stationary night blindness (complete and incomplete CSNB), melanoma-associated retinopathy, and some forms of autoimmune retinopathy. The photopic On-Off ERGs may also be useful in X-linked retinoschisis, Batten disease, Duchenne muscular dystrophy, spinocerebellar degeneration, quinine toxicity, and other retinal disorders.
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Abalem MF, Musch DC, Birch DG, Pennesi ME, Heckenlively JR, Jayasundera T. Diurnal variations of foveoschisis by optical coherence tomography in patients with RS1 X-linked juvenile retinoschisis. Ophthalmic Genet 2018; 39:437-442. [PMID: 29902095 DOI: 10.1080/13816810.2018.1466340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
BACKGROUND To evaluate diurnal variations in macular schisis cavities in patients with X-linked juvenile retinoschisis (XLRS) with pathogenic variants in the RS1 gene using spectral-domain optical coherence tomography (SD-OCT). METHODS Three consecutive patients with a clinical diagnosis of XLRS and pathogenic variants in the RS1, treated with carbonic anhydrase inhibitors (CAIs). Observational procedures: SD-OCT scans of the macula were acquired at 9 a.m., 1 p.m., and 4 p.m. within 24 h. RESULTS All patients demonstrated increased measures of central foveal thickness in the morning with gradual decrease through the day (9-43%). Major changes were observed between 9 a.m. and 1 p.m. in the central foveal thickness. CONCLUSION The central foveal thickness varies during daytime hours in patients with XLRS. This finding may explain the inconsistent and heterogeneous responses to treatment with CAIs and necessitate standardization of measurement times in treatment trials for XLRS as well as in the routine ophthalmic evaluation of these patients.
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Affiliation(s)
- Maria Fernanda Abalem
- a Department of Ophthalmology and Visual Sciences, Kellogg Eye Center , University of Michigan Medical School , Ann Arbor , MI , USA.,b Department of Ophthalmology and Otolaryngology , University of Sao Paulo Medical School , Sao Paulo , Brazil
| | - David C Musch
- a Department of Ophthalmology and Visual Sciences, Kellogg Eye Center , University of Michigan Medical School , Ann Arbor , MI , USA.,c Department of Epidemiology , University of Michigan School of Public Health , Ann Arbor , MI , USA
| | - David G Birch
- d Retina Foundation of the Southwest , Dallas , TX , USA
| | - Mark E Pennesi
- e Casey Eye Institute , Oregon Health & Science University , Portland , OR , USA
| | - John R Heckenlively
- a Department of Ophthalmology and Visual Sciences, Kellogg Eye Center , University of Michigan Medical School , Ann Arbor , MI , USA
| | - Thiran Jayasundera
- a Department of Ophthalmology and Visual Sciences, Kellogg Eye Center , University of Michigan Medical School , Ann Arbor , MI , USA
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Orès R, Mohand-Said S, Dhaenens CM, Antonio A, Zeitz C, Augstburger E, Andrieu C, Sahel JA, Audo I. Phenotypic Characteristics of a French Cohort of Patients with X-Linked Retinoschisis. Ophthalmology 2018; 125:1587-1596. [PMID: 29739629 DOI: 10.1016/j.ophtha.2018.03.057] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 03/25/2018] [Accepted: 03/28/2018] [Indexed: 10/17/2022] Open
Abstract
PURPOSE To analyze the retinal structure in patients with X-linked retinoschisis (XLRS) using spectral-domain OCT and to correlate the morphologic findings with visual acuity, electroretinographic results, and patient age. DESIGN Retrospective, observational study. PARTICIPANTS Data from 52 consecutive male patients with molecularly confirmed XLRS were collected retrospectively. METHODS Complete clinical evaluation included best-corrected visual acuity, full-field electroretinography, fundus photography, spectral-domain OCT, and fundus autofluorescence. Spectral-domain OCT images were analyzed to determine full thickness of the retina and tomographic structural changes. MAIN OUTCOME MEASURES Relationships between age, OCT, and visual acuity were assessed. RESULTS One hundred four eyes of 52 patients were included. The mean age at inclusion was 24±15 years (range, 3-57 years). The best-corrected visual acuity ranged from no light perception to 0.1 logarithm of the minimum angle of resolution (mean, 0.6±0.38 logarithm of the minimum angle of resolution). Macular schisis was found in 88% of eyes and macular atrophy was found in 11% of eyes, whereas peripheral schisis was present in 30% of eyes. A spoke-wheel pattern of high and low intensity was the most frequently observed fundus autofluorescence abnormality (51/94 eyes [54%]). The b-to-a amplitude ratio on bright-flash dark-adapted electroretinography was reduced significantly in 45 of 64 eyes (70%). Spectral-domain OCT was available for 97 eyes and showed foveoschisis in 76 of 97 eyes (78%), parafoveal schisis in 10 of 97 eyes (10%), and foveal atrophy in 11 of 97 eyes (11%). Mean central macular thickness (CMT) was of 373.6±140 μm. Cystoid changes were localized mainly in the inner nuclear layer (85/97 eyes [88%]). Qualitative defects in photoreceptor structures were found in most eyes (79/97 eyes [81%]), and the most frequent abnormality was an interruption of the photoreceptor cell outer segment tips (79/79 eyes [100%]). Older age correlated well with lower CMT (correlation coefficient [CC], -0.44; P < 0.001) and with lower photoreceptor outer segment (PROS) length (CC, -0.42; P < 0.001). Lower visual acuity correlated strongly with lower PROS length (CC, -0.53; P < 0.001). CONCLUSIONS This study underlined the wide variety of clinical features of XLRS. It highlighted the correlation between visual acuity, patient age, and OCT features, emphasizing the relevance of the latter as potential outcome measure in clinical trials.
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Affiliation(s)
- Raphaëlle Orès
- Centre de Maladies Rares "Dystrophies Rétiniennes d'Origine Génétique," DHU Sight Restore INSERM-DHOS CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Saddek Mohand-Said
- Centre de Maladies Rares "Dystrophies Rétiniennes d'Origine Génétique," DHU Sight Restore INSERM-DHOS CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France; INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - Claire-Marie Dhaenens
- Department of Biochemistry and Molecular Biology-UF Génopathies, Université Lille, Inserm UMR-S 1172, CHU Lille, Lille, France
| | - Aline Antonio
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - Christina Zeitz
- INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France
| | - Edouard Augstburger
- Centre de Maladies Rares "Dystrophies Rétiniennes d'Origine Génétique," DHU Sight Restore INSERM-DHOS CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - Camille Andrieu
- Centre de Maladies Rares "Dystrophies Rétiniennes d'Origine Génétique," DHU Sight Restore INSERM-DHOS CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France
| | - José-Alain Sahel
- Centre de Maladies Rares "Dystrophies Rétiniennes d'Origine Génétique," DHU Sight Restore INSERM-DHOS CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France; INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France; Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Isabelle Audo
- Centre de Maladies Rares "Dystrophies Rétiniennes d'Origine Génétique," DHU Sight Restore INSERM-DHOS CIC 1423, Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, Paris, France; INSERM, CNRS, Institut de la Vision, Sorbonne Université, Paris, France.
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24
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Coussa RG, Kapusta MA. Treatment of cystic cavities in X-linked juvenile retinoschisis: The first sequential cross-over treatment regimen with dorzolamide. Am J Ophthalmol Case Rep 2017; 8:1-3. [PMID: 29260104 PMCID: PMC5731553 DOI: 10.1016/j.ajoc.2017.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 07/03/2017] [Accepted: 07/19/2017] [Indexed: 11/30/2022] Open
Abstract
Purpose To report the first sequential cross-over treatment with the longest ophthalmic follow-up in a case of X-linked juvenile retinoschisis (XLRS) successfully treated with topical dorzolamide. Observations A healthy 34 year-old man presented with one month history of decreased visual acuity in his left eye. Funduscopy was significant for a blunted and cystoid-like foveal reflex in both eyes. The macular OCT showed cystic foveal changes OU. The patient was diagnosed with XLRS and was observed. On two subsequent follow-ups, a significant decrease in the patient's visual acuity warranted the use of topical dorzolamide for treating the cystic foveal changes, which completely resolved two months post-treatment initiation. Conclusion and importance Previous reports showed the benefit of dorzolamide in treating foveal cystic cavities in XLRS. To our knowledge, this is the first case of XLRS demonstrating the benefits of topical dorzolamide based on a sequential cross-over treatment regimen. It may also represent a case with the longest ophthalmic follow-up providing, in consequence, long-term understanding of the natural history and complications of this rare disease After ruling out major causes of cystoid macular edema, XLRS patients presenting with worsening of their visual acuities due to larger cystic macular changes may benefit from an alternating ON/OFF regimen of topical dorzolamide, which offers a significant treatment advantage outweighing its well-known side effects. Our study consolidates the importance of “medication vacation” by showing its efficacy in providing anatomical and visual functional improvements in patients with chronic cystic macular changes.
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Affiliation(s)
- Razek Georges Coussa
- Department of Ophthalmology, Jewish General Hospital, McGill University Health Center, 3755 Côte-Ste-Catherine Road, E-030, Montreal, Quebec, H3T 1E2, Canada
| | - Michael Alton Kapusta
- Department of Ophthalmology, Jewish General Hospital, McGill University Health Center, 3755 Côte-Ste-Catherine Road, E-030, Montreal, Quebec, H3T 1E2, Canada
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25
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Plössl K, Royer M, Bernklau S, Tavraz NN, Friedrich T, Wild J, Weber BHF, Friedrich U. Retinoschisin is linked to retinal Na/K-ATPase signaling and localization. Mol Biol Cell 2017; 28:2178-2189. [PMID: 28615319 PMCID: PMC5531734 DOI: 10.1091/mbc.e17-01-0064] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 06/02/2017] [Accepted: 06/06/2017] [Indexed: 01/30/2023] Open
Abstract
Retinoschisin binds to the extracellular domain of Na/K-ATPase subunit β2. Retinoschisin inhibits Na/K-ATPase–associated signaling cascades and affects Na/K-ATPase localization. The retinoschisin-Na/K-ATPase complex overlaps with signaling mediators. Defective Na/K-ATPase signaling by retinoschisin deficiency may promote retinal dystrophy. Mutations in the RS1 gene cause X-linked juvenile retinoschisis (XLRS), a hereditary retinal dystrophy. We recently showed that retinoschisin, the protein encoded by RS1, regulates ERK signaling and apoptosis in retinal cells. In this study, we explored an influence of retinoschisin on the functionality of the Na/K-ATPase, its interaction partner at retinal plasma membranes. We show that retinoschisin binding requires the β2-subunit of the Na/K-ATPase, whereas the α-subunit is exchangeable. Our investigations revealed no effect of retinoschisin on Na/K-ATPase–mediated ATP hydrolysis and ion transport. However, we identified an influence of retinoschisin on Na/K-ATPase–regulated signaling cascades and Na/K-ATPase localization. In addition to the known ERK deactivation, retinoschisin treatment of retinoschisin-deficient (Rs1h-/Y) murine retinal explants decreased activation of Src, an initial transmitter in Na/K-ATPase signal transduction, and of Ca2+ signaling marker Camk2. Immunohistochemistry on murine retinae revealed an overlap of the retinoschisin–Na/K-ATPase complex with proteins involved in Na/K-ATPase signaling, such as caveolin, phospholipase C, Src, and the IP3 receptor. Finally, retinoschisin treatment altered Na/K-ATPase localization in photoreceptors of Rs1h-/Y retinae. Taken together, our results suggest a regulatory effect of retinoschisin on Na/K-ATPase signaling and localization, whereas Na/K-ATPase-dysregulation caused by retinoschisin deficiency could represent an initial step in XLRS pathogenesis.
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Affiliation(s)
- Karolina Plössl
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
| | - Melanie Royer
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
| | - Sarah Bernklau
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
| | - Neslihan N Tavraz
- Institute of Chemistry, Technical University of Berlin, 10623 Berlin, Germany
| | - Thomas Friedrich
- Institute of Chemistry, Technical University of Berlin, 10623 Berlin, Germany
| | - Jens Wild
- Institute of Clinical Microbiology and Hygiene, University Hospital of Regensburg, University of Regensburg, 93053 Regensburg, Germany
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
| | - Ulrike Friedrich
- Institute of Human Genetics, University of Regensburg, 93053 Regensburg, Germany
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Altschwager P, Ambrosio L, Swanson EA, Moskowitz A, Fulton AB. Juvenile Macular Degenerations. Semin Pediatr Neurol 2017; 24:104-109. [PMID: 28941524 PMCID: PMC5709045 DOI: 10.1016/j.spen.2017.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In this article, we review the following 3 common juvenile macular degenerations: Stargardt disease, X-linked retinoschisis, and Best vitelliform macular dystrophy. These are inherited disorders that typically present during childhood, when vision is still developing. They are sufficiently common that they should be included in the differential diagnosis of visual loss in pediatric patients. Diagnosis is secured by a combination of clinical findings, optical coherence tomography imaging, and genetic testing. Early diagnosis promotes optimal management. Although there is currently no definitive cure for these conditions, therapeutic modalities under investigation include pharmacologic treatment, gene therapy, and stem cell transplantation.
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Affiliation(s)
- Pablo Altschwager
- Departamento de Oftalmología, Escuela de Medicina, Pontificia, Universidad Católica de Chile, Santiago, Chile.
| | - Lucia Ambrosio
- Department of Ophthalmology, Children's Hospital, Boston, MA 02115 USA,Department of Ophthalmology, Harvard Medical School, Boston, MA 02115 USA
| | - Emily A. Swanson
- Department of Ophthalmology, Children's Hospital, Boston, MA 02115 USA
| | - Anne Moskowitz
- Department of Ophthalmology, Children's Hospital, Boston, MA 02115 USA,Department of Ophthalmology, Harvard Medical School, Boston, MA 02115 USA
| | - Anne B. Fulton
- Department of Ophthalmology, Children's Hospital, Boston, MA 02115 USA,Department of Ophthalmology, Harvard Medical School, Boston, MA 02115 USA
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Fahim AT, Ali N, Blachley T, Michaelides M. Peripheral fundus findings in X-linked retinoschisis. Br J Ophthalmol 2017; 101:1555-1559. [DOI: 10.1136/bjophthalmol-2016-310110] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 02/27/2017] [Accepted: 03/03/2017] [Indexed: 12/25/2022]
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28
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Nicoletti A, Ziccardi L, Maltese PE, Benedetti S, Palumbo O, Rendina M, D'Agruma L, Falsini B, Wang X, Bertelli M. Design and Validation of a New MLPA-Based Assay for the Detection of RS1 Gene Deletions and Application in a Large Family with X-Linked Juvenile Retinoschisis. Genet Test Mol Biomarkers 2016; 21:116-121. [PMID: 27997221 DOI: 10.1089/gtmb.2016.0257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
AIMS X-linked juvenile retinoschisis (XLRS) is a severe ocular disorder that can evolve to blindness. More than 200 different disease-causing mutations have been reported in the RS1 gene and approximately 10% of these are deletions. Since transmission is X-linked, males are always affected and females are usually carriers. The identification of female carriers is always important and poses a technical challenge. Therefore, we sought to develop a multiplex ligation dependent probe amplification (MLPA)-based method to identify deletions or duplications in this gene. We then used our assay to study a large XLRS family. METHODS We designed six probes specific for each RS1 exon and then optimized and validated our method using control samples with known gene deletions. In the XLRS family, RS1 gene copy number variation was assessed by "home-made" MLPA analysis and by single nucleotide polymorphism (SNP) array analysis using the CytoScan HD Array. Direct sequencing was used for deletion breakpoint mapping. RESULTS Our assay detected all deletions in control samples. All affected males of the family were positive for a deletion of exon 2 of the RS1 gene (RS1:NM_000330:c.53-?_78+?del). Carrier females were also identified. CONCLUSION Our method is easily replicated, reliable, and inexpensive and allows female carriers to be detected. This is the first report of deep characterization of a whole exon deletion in the RS1 gene.
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Affiliation(s)
- Annalisa Nicoletti
- 1 MAGI Non-Profit Human Medical Genetics Institute , Rovereto, Trento, Italy
- 2 Department of Medical and Surgical Sciences (DIMEC), University of Bologna , Bologna, Italy
| | | | | | - Sabrina Benedetti
- 1 MAGI Non-Profit Human Medical Genetics Institute , Rovereto, Trento, Italy
| | - Orazio Palumbo
- 4 Medical Genetics Service, "IRCCS Casa Sollievo della Sofferenza," San Giovanni Rotondo, Italy
| | - Michelina Rendina
- 4 Medical Genetics Service, "IRCCS Casa Sollievo della Sofferenza," San Giovanni Rotondo, Italy
| | - Leonardo D'Agruma
- 4 Medical Genetics Service, "IRCCS Casa Sollievo della Sofferenza," San Giovanni Rotondo, Italy
| | - Benedetto Falsini
- 5 Institute of Ophthalmology, Policlinico Gemelli, Catholic University , Roma, Italy
| | - Xinjing Wang
- 6 DNA Diagnostic Laboratory, Ophthalmic Genetics and Visual Function Branch, National Eye Institute/NIH , Bethesda, Maryland
| | - Matteo Bertelli
- 1 MAGI Non-Profit Human Medical Genetics Institute , Rovereto, Trento, Italy
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Bennett LD, Wang YZ, Klein M, Pennesi ME, Jayasundera T, Birch DG. Structure/Psychophysical Relationships in X-Linked Retinoschisis. Invest Ophthalmol Vis Sci 2016; 57:332-7. [PMID: 26830370 PMCID: PMC4736741 DOI: 10.1167/iovs.15-18354] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To compare structural properties from spectral-domain optical coherence tomography (SDOCT) and psychophysical measures from a subset of patients enrolled in a larger multicenter natural history study of X-linked retinoschisis (XLRS). METHODS A subset of males (n = 24) participating in a larger natural history study of XLRS underwent high-resolution SDOCT. Total retina (TR) thickness and outer segment (OS) thickness were measured manually. Shape discrimination hyperacuity (SDH) and contour integration perimetry (CIP) were performed on an iPad with the myVisionTrack application. Sensitivity was measured with fundus-guided perimetry (4-2 threshold testing strategy; 10-2 grid, spot size 3, 68 points). Correlation was determined with Pearson's r correlation. Values are presented as the mean ± SD. RESULTS Mean macular OS thickness was less in XLRS patients (17.2 ± 8.1 μm) than in controls (37.1 ± 5.7 μm; P < 0.0001) but mean TR thickness was comparable (P = 0.5884). For patients, total sensitivity was lower (13.2 ± 6.6 dB) than for controls (24.2 ± 2.4 dB; P = 0.0008) and had a strong correlation with photoreceptor OS (R(2) = 0.55, P = 0.0001) and a weak correlation with TR thickness (R(2) = 0.22, P = 0.0158). The XLRS subjects had a logMAR best corrected visual acuity (BCVA) of 0.5 ± 0.3 that was associated with OS (R(2) = 0.79, P < 0.0001) but not TR thickness (R(2) = 0.01, P = 0.6166). Shape DH and CIP inner ring correlated with OS (R(2) = 0.33, P = 0.0085 and R(2) = 0.47, P = 0.0001, respectively) but not TR thickness (R(2) = 0.0004, P = 0.93; R(2) = 0.0043, P = 0.75, respectively). CONCLUSIONS When considered from a single visit, OS thickness within the macula is more closely associated with macular function than TR thickness within the macula in patients with XLRS.
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Affiliation(s)
- Lea D Bennett
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Yi-Zhong Wang
- Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Martin Klein
- Retina Foundation of the Southwest, Dallas, Texas, United States
| | - Mark E Pennesi
- Oregon Health & Science University, Casey Eye Institute, Portland, Oregon, United States
| | - Thiran Jayasundera
- University of Michigan, Kellogg Eye Center, Ann Arbor, Michigan, United States
| | - David G Birch
- Retina Foundation of the Southwest, Dallas, Texas, United States 2Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas, United States
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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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31
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Jeffrey BG, Cukras CA, Vitale S, Turriff A, Bowles K, Sieving PA. Test-Retest Intervisit Variability of Functional and Structural Parameters in X-Linked Retinoschisis. Transl Vis Sci Technol 2014; 3:5. [PMID: 25346871 DOI: 10.1167/tvst.3.5.5] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 06/30/2014] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To examine the variability of four outcome measures that could be used to address safety and efficacy in therapeutic trials with X-linked juvenile retinoschisis. METHODS Seven men with confirmed mutations in the RS1 gene were evaluated over four visits spanning 6 months. Assessments included visual acuity, full-field electroretinograms (ERG), microperimetric macular sensitivity, and retinal thickness measured by optical coherence tomography (OCT). Eyes were separated into Better or Worse Eye groups based on acuity at baseline. Repeatability coefficients were calculated for each parameter and jackknife resampling used to derive 95% confidence intervals (CIs). RESULTS The threshold for statistically significant change in visual acuity ranged from three to eight letters. For ERG a-wave, an amplitude reduction greater than 56% would be considered significant. For other parameters, variabilities were lower in the Worse Eye group, likely a result of floor effects due to collapse of the schisis pockets and/or retinal atrophy. The criteria for significant change (Better/Worse Eye) for three important parameters were: ERG b/a-wave ratio (0.44/0.23), point wise sensitivity (10.4/7.0 dB), and central retinal thickness (31%/18%). CONCLUSIONS The 95% CI range for visual acuity, ERG, retinal sensitivity, and central retinal thickness relative to baseline are described for this cohort of participants with X-linked juvenile retinoschisis (XLRS). TRANSLATIONAL RELEVANCE A quantitative understanding of the variability of outcome measures is vital to establishing the safety and efficacy limits for therapeutic trials of XLRS patients.
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Affiliation(s)
- Brett G Jeffrey
- National Eye Institute, National Institutes of Health, Bethesda, MD
| | | | - Susan Vitale
- National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Amy Turriff
- National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Kristin Bowles
- Current address: College of Optometry, University of Houston, TX ; National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, MD
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Huang Y, Mei L, Gui B, Su W, Liang D, Wu L, Pan Q. A novel deletion mutation in RS1 gene caused X-linked juvenile retinoschisis in a Chinese family. Eye (Lond) 2014; 28:1364-9. [PMID: 25168411 DOI: 10.1038/eye.2014.196] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Accepted: 06/26/2014] [Indexed: 11/09/2022] Open
Abstract
PURPOSE 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. This study aimed to identify the underlying genetic defect in a Chinese family with XLRS. METHODS The proband underwent complete ophthalmic examinations, including fundus examination, fundus autofluorescence, and optical coherence tomography. DNA extracted from proband and his younger brother was screened for mutations in RS1 gene. The detected RS1 mutation was tested in all available family members and 200 healthy controls. RESULTS Reduced visual acuity, spoke-wheel pattern at the fovea, and split retina were observed in the proband. A novel frameshift mutation c.206-207delTG in the RS1 gene, leading to a truncated protein (p.L69fs16X), was identified in the proband and his younger brother. This mutation was not found in any unaffected member or in the healthy controls. The mother of the proband was hemizygous for this mutant allele. CONCLUSIONS We identified a novel causative mutation of RS1 in a Chinese family with XLRS. This finding expands the mutation spectrum of RS1 and provides evidence for a phenotype-genotype study in XLRS.
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Affiliation(s)
- Y Huang
- State Key Laboratory of Medical Genetics, Xiangya Hospital, Central South University, Changsha, China
| | - L Mei
- State Key Laboratory of Medical Genetics, Xiangya Hospital, Central South University, Changsha, China
| | - B Gui
- State Key Laboratory of Medical Genetics, Xiangya Hospital, Central South University, Changsha, China
| | - W Su
- State Key Laboratory of Medical Genetics, Xiangya Hospital, Central South University, Changsha, China
| | - D Liang
- State Key Laboratory of Medical Genetics, Xiangya Hospital, Central South University, Changsha, China
| | - L Wu
- State Key Laboratory of Medical Genetics, Xiangya Hospital, Central South University, Changsha, China
| | - Q Pan
- State Key Laboratory of Medical Genetics, Xiangya Hospital, Central South University, Changsha, China
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Vukmanic E, Godwin K, Shi P, Hughes A, DeMarco P. Full-field electroretinogram response to increment and decrement stimuli. Doc Ophthalmol 2014; 129:85-95. [PMID: 25074040 DOI: 10.1007/s10633-014-9455-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 07/16/2014] [Indexed: 11/24/2022]
Abstract
PURPOSE The d-wave is typically elicited after the termination of an increment flash, but a decrement flash provides an alternative, and perhaps more appropriate, stimulus to elicit the d-wave. Here, we investigated the affects of stimulus polarity on the electroretinogram (ERG) response. METHODS ERG responses elicited to increment and decrement flashes of varying intensity and duration from different background levels were measured from human participants to assess the b-wave and d-wave responses as a function of adaptation level and flash polarity. Response amplitudes were measured using standard metrics for waveform analysis. RESULTS The amplitude of the b-wave is larger than the d-wave regardless of flash polarity when using different background levels which maximized the dynamic range of the two waveforms. However, when response amplitudes are measured from a common background, the d-wave elicited with decrement flash was larger than the b-wave elicited by an increment flash. This trend was evident across a range of background levels. The b-wave and d-wave become separate entities when flash duration reaches approximately 50 ms. Rapid-on and rapid-off sawtooth stimuli were also tested against increment and decrement step stimuli that were matched in mean luminance. These two stimulus types produced different amplitude b-wave and d-wave responses, suggesting asymmetric effects of the two stimulus types on the retinal response. CONCLUSIONS We conclude that the response properties of the b-wave and d-wave are influenced by the duration, polarity and waveform of the stimulus, as well as the background from which the stimuli arise.
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Affiliation(s)
- Eric Vukmanic
- Department of Psychological and Brain Sciences, 317 Life Sciences Bldg., University of Louisville, Louisville, KY, USA
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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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Cox KF, Kerr NC, Kedrov M, Nishimura D, Jennings BJ, Stone EM, Sheffield VC, Iannaccone A. Phenotypic expression of Bardet-Biedl syndrome in patients homozygous for the common M390R mutation in the BBS1 gene. Vision Res 2012; 75:77-87. [PMID: 22940089 DOI: 10.1016/j.visres.2012.08.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Revised: 08/07/2012] [Accepted: 08/08/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE To characterize the phenotype of Bardet-Biedl syndrome (BBS) patients homozygous for the BBS1 M390R mutation. METHODS Three patients [PT1, F, 27 years old (yo) at last examination, 14-year follow-up (F/U) PT2, F, 15-yo PT3, M, 15-yo, both 1-year F/U] underwent eye exams, Goldmann visual fields (GVFs), dark- (DA) and light-adapted (LA) electroretinograms (ERGs), spectral domain optical coherence tomography (SD-OCT) and fundus autofluorescence (FAF). Vision and systemic history were also collected. RESULTS All patients had night blindness, hyperopic astigmatism, ptosis or mild blepharospasm, foot polydactyly, 5th finger clinodactyly, history of headaches, and variable, diet-responsive obesity. Two had asthma, PT1 was developmentally delayed, PT2 had Asperger-like symptoms, and PT3 had normal cognition. At age 14, acuity was 20/100 in PT1, who had nystagmus since age 2, 20/40 in PT2 and 20/30 in PT3. By 27yo PT1 progressed to 20/320, by 15 yo PT2 was 20/60 and PT3 remained stable. PT1 had well preserved peripheral GVFs, with minimal progression over 10 years of F/U. PT2 and PT3 presented with ring scotomas and I4e<5°. All patients had severe generalized visual sensitivity depression. ERGs were consistently recordable (also rod ERG in PT3 after 60 min DA), but progressed to non-recordable in PT1. Mixed DA ERGs exhibited electronegativity. In PT3, this was partly due to a bleaching effect during bright-flash DA averaging, partly to ON≫OFF LA response compromise. PT2 and 3 had, on SD-OCTs, generalized macular thinning, normal retinal lamination, and widespread photoreceptor outer/inner segment attenuation except foveally, and multiple rings of abnormal FAF configuring a complex bull's eye-pattern. PT1 had macular atrophy. All patients also had peripapillary nerve fiber layer thickening. CONCLUSIONS The observed phenotype matches very closely that reported in patients by Azari et al. (IOVS 2006) and in the Bbs1-M390R knock-in mouse model, and expands it to the characterization of important ERG response characteristics that provide insight in the pathogenesis of retinopathy in these patients. Our findings confirm the consistent pathogenicity of the BBS1 M390R mutation.
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Affiliation(s)
- Kyle F Cox
- University of Tennessee Health Science Center, Hamilton Eye Institute, Memphis, TN 38163, USA
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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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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, Ziccardi L, Sieving PA. Biology of retinoschisin. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 723:513-8. [PMID: 22183371 PMCID: PMC3475158 DOI: 10.1007/978-1-4614-0631-0_64] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- Camasamudram Vijayasarathy
- Section for Translation Research in Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Lucia Ziccardi
- Neurophthalmology Unit, Fondazione “G.B. Bietti” IRCCS, Via Livenza, 300198 Rome, Italy
| | - Paul A. Sieving
- National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Duncan JL, Ratnam K, Birch DG, Sundquist SM, Lucero AS, Zhang Y, Meltzer M, Smaoui N, Roorda A. Abnormal cone structure in foveal schisis cavities in X-linked retinoschisis from mutations in exon 6 of the RS1 gene. Invest Ophthalmol Vis Sci 2011; 52:9614-23. [PMID: 22110067 DOI: 10.1167/iovs.11-8600] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To evaluate macular cone structure in patients with X-linked retinoschisis (XLRS) caused by mutations in exon 6 of the RS1 gene. METHODS High-resolution macular images were obtained with adaptive optics scanning laser ophthalmoscopy (AOSLO) and spectral domain optical coherence tomography (SD-OCT) in two patients with XLRS and 27 age-similar healthy subjects. Retinal structure was correlated with best-corrected visual acuity, kinetic and static perimetry, fundus-guided microperimetry, full-field electroretinography (ERG), and multifocal ERG. The six coding exons and the flanking intronic regions of the RS1 gene were sequenced in each patient. RESULTS Two unrelated males, ages 14 and 29, with visual acuity ranging from 20/32 to 20/63, had macular schisis with small relative central scotomas in each eye. The mixed scotopic ERG b-wave was reduced more than the a-wave. SD-OCT showed schisis cavities in the outer and inner nuclear and plexiform layers. Cone spacing was increased within the largest foveal schisis cavities but was normal elsewhere. In each patient, a mutation in exon 6 of the RS1 gene was identified and was predicted to change the amino acid sequence in the discoidin domain of the retinoschisin protein. CONCLUSIONS AOSLO images of two patients with molecularly characterized XLRS revealed increased cone spacing and abnormal packing in the macula of each patient, but cone coverage and function were near normal outside the central foveal schisis cavities. Although cone density is reduced, the preservation of wave-guiding cones at the fovea and eccentric macular regions has prognostic and therapeutic implications for XLRS patients with foveal schisis. (Clinical Trials.gov number, NCT00254605.).
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Affiliation(s)
- Jacque L Duncan
- Department of Ophthalmology, University of California at San Francisco, San Francisco, California 94143, USA.
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Bowles K, Cukras C, Turriff A, Sergeev Y, Vitale S, Bush RA, Sieving PA. X-linked retinoschisis: RS1 mutation severity and age affect the ERG phenotype in a cohort of 68 affected male subjects. Invest Ophthalmol Vis Sci 2011; 52:9250-6. [PMID: 22039241 DOI: 10.1167/iovs.11-8115] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To assess the effect of age and RS1 mutation on the phenotype of X-linked retinoschisis (XLRS) subjects using the clinical electroretinogram (ERG) in a cross-sectional analysis. METHODS Sixty-eight XLRS males 4.5 to 55 years of age underwent genotyping, and the retinoschisis (RS1) mutations were classified as less severe (27 subjects) or more severe (41 subjects) based on the putative impact on the protein. ERG parameters of retinal function were analyzed by putative mutation severity with age as a continuous variable. RESULTS The a-wave amplitude remained greater than the lower limit of normal (mean, -2 SD) for 72% of XLRS males and correlated with neither age nor mutation class. However, b-wave and b/a-ratio amplitudes were significantly lower in the more severe than in the less severe mutation groups and in older than in younger subjects. Subjects up to 10 years of age with more severe RS1 mutations had significantly greater b-wave amplitudes and faster a-wave trough implicit times than older subjects in this group. CONCLUSIONS RS1 mutation putative severity and age both had significant effects on retinal function in XLRS only in the severe mutation group, as judged by ERG analysis of the b-wave amplitude and the b/a-ratio, whereas the a-wave amplitude remained normal in most. A new observation was that increasing age (limited to those aged 55 and younger) caused a significant delay in XLRS b-wave onset (i.e., a-wave implicit time), even for those who retained considerable b-wave amplitudes. The delayed b-wave onset suggested that dysfunction of the photoreceptor synapse or of bipolar cells increases with age of XLRS subjects.
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Affiliation(s)
- Kristen Bowles
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, Bethesda, Maryland 20892, USA
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EFFECT OF AGING ON MACULAR FEATURES OF X-LINKED RETINOSCHISIS ASSESSED WITH OPTICAL COHERENCE TOMOGRAPHY. Retina 2011; 31:1186-92. [DOI: 10.1097/iae.0b013e3181ff0d2d] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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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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A novel mutation (Cys83Tyr) in the second zinc finger of NR2E3 in enhanced S-cone syndrome. Graefes Arch Clin Exp Ophthalmol 2010; 249:201-8. [PMID: 20725840 DOI: 10.1007/s00417-010-1482-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2009] [Revised: 07/25/2010] [Accepted: 07/26/2010] [Indexed: 10/19/2022] Open
Abstract
BACKGROUND Enhanced S-cone syndrome (ESCS) is an autosomal recessive retinal disorder characterized by an increased number of S-cones over L/M cones and rods. Mutations in the NR2E3 gene, encoding a photoreceptor-specific nuclear receptor, are identified in patients with ESCS. The purpose of this study is to report the ophthalmic features of a 25-year-old Portuguese male with a typical ESCS phenotype and a novel homozygous NR2E3 mutation. METHODS The patient underwent a detailed ophthalmic examination including fundus photography, fluorescein angiography (FAF), fundus autofluorescence imaging (FAI), and spectral domain optical coherence tomography (SD-OCT). Full-field electroretinography (ERG), S-cone ERG, and multifocal ERG were performed. Mutation screening of the NR2E3 gene was performed with polymerase chain reaction amplification and direct sequencing. RESULTS The patient had poor visual acuity but good color vision. Funduscopy showed degenerative changes from the vascular arcades to the midperipheral retina. The SD-OCT revealed macular schisis and cystoid changes that had no fluorescein leakage. The posterior pole showed diffusely increased autofluorescence compared with eccentric areas in both eyes. International-standard full-field ERG showed the typical pathognomonic changes associated with ESCS and the short-wavelength flash ERG was simplified, delayed, and similar to the standard photopic flash ERG. Multifocal ERG showed widespread delay and reduction. Genetic analysis revealed a novel homozygous mutation (p.C83Y), which resides in the second zinc finger of the DNA-binding domain. CONCLUSIONS This homozygous mutation is likely to affect binding to target DNA sites, resulting in a non-functional behavior of NR2E3 protein. It is associated with a typical form of ESCS with a nondetectable rod response and reduced/delayed mfERG responses at all eccentricities.
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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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Takada Y, Vijayasarathy C, Zeng Y, Kjellstrom S, Bush RA, Sieving PA. Synaptic pathology in retinoschisis knockout (Rs1-/y) mouse retina and modification by rAAV-Rs1 gene delivery. Invest Ophthalmol Vis Sci 2008; 49:3677-86. [PMID: 18660429 DOI: 10.1167/iovs.07-1071] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE At an early age, the retinoschisin knockout (Rs1-KO) mouse retina has progressive photoreceptor degeneration with severe disruption of the outer plexiform layer (OPL) that decreases at older ages. The electroretinogram (ERG) undergoes parallel changes. The b-wave amplitude from bipolar cells is reduced disproportionately to the photoreceptor a-wave at young but not at older ages. The protein expression and morphology of the OPL in Rs1-KO mice was investigated at different ages, to explore the role of the synaptic layer in these ERG changes. METHODS Retinas of wild-type (Wt) and Rs1-KO mice from postnatal day (P)7 to 12 months were evaluated by light and electron microscopy (EM) and biochemistry. PSD95 (postsynaptic density protein), mGluR6 (metabotropic glutamate receptor subtype 6), retinoschisin (Rs1), the Müller cell proteins glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), the bipolar cell marker protein kinase C alpha (PKCalpha), and the horizontal cell marker calbindin were localized by immunofluorescence and immuno-EM. Levels of PSD95 and mGluR6 were determined by quantitative Western blot. Rs1-KO mice treated by intravitreous injection of rAAV(2/2)-CMV-Rs1 in one eye at P14 were evaluated at 8 months by full-field scotopic ERG responses and retinal immunohistochemistry. RESULTS Rs1 was associated with the outer surface of synaptic membranes in wild-type (Wt) retinas. PSD95 and mGluR6 were juxtaposed in the OPL of the Rs1-KO retinas by P14, implying that synaptic structures are formed. Light microscopic retinal morphology was similar in Wt and Rs1-KO at P14, but by P21, the OPL was disrupted in Rs1-KO, and some PSD95 and mGluR6 was mislocalized in the outer nuclear layer (ONL). GFAP expression spanned all retinal layers. EM showed synaptic structures adjacent to photoreceptor nuclei. PSD95 and mGluR6 levels were normal at 1 month on Western blot but declined to 59% (P < 0.001) and 55% (P < 0.05) of Wt, respectively, by 4 months. Levels thereafter showed no further reduction out to 12 months. Eyes injected with AAV-Rs1 were studied at 8 months by immunohistochemistry and had higher expression of PSD95 and mGluR6 and less GFAP expression compared with fellow untreated eyes. CONCLUSIONS In the Rs1-KO mouse, retinal layer formation and synaptic protein expression in the OPL is normal up to P14, implying normal development of synaptic connections. Aberrant localization of synaptic proteins by P21 indicates that displacement of developing and/or mature synapses contributes to the b-wave reduction at young ages, when photoreceptor numbers and synaptic protein levels are normal. The subsequent decline in PSD95 and mGluR6 between 1 and 12 months in Rs1-KO retina mirrors the course of b-wave change and provides evidence of causal relationship between the ERG and OPL changes. These findings and the improved structural integrity of the OPL and b-wave amplitude after Rs1 gene transfer therapy provide a cellular and molecular basis for interpreting the changes in retinal signaling in this model.
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Affiliation(s)
- Yuichiro Takada
- Section for Translational Research in Retinal and Macular Degeneration, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland 20892, USA
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Gerth C, Zawadzki RJ, Werner JS, Héon E. Retinal morphological changes of patients with X-linked retinoschisis evaluated by Fourier-domain optical coherence tomography. ACTA ACUST UNITED AC 2008; 126:807-11. [PMID: 18541843 DOI: 10.1001/archopht.126.6.807] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To investigate the retinal microstructure and lamination of patients affected with X-linked retinoschisis (XLRS) using high-resolution imaging modalities. METHODS Patients diagnosed as having XLRS underwent assessment. Visual function testing included visual acuity, color vision, and full-field electroretinography. We used a high-resolution Fourier-domain optical coherence tomography (FD-OCT) system (4.5-mum axial resolution; 9 frames/s; 1000 A-scans per frame) combined with a handheld scanner. Macular image evaluation included schisis localization and retinal layer integrity. RESULTS Six patients with XLRS and identified mutations in the XLRS1 gene underwent testing. Visual acuity ranged from 0.2 to 1.6 logMAR (logarithm of the minimum angle of resolution). Results of FD-OCT revealed foveal schisis extending from the outer to the inner plexiform layer in 4 of 6 patients. Bullous foveal schisis was associated with younger age. All patients showed extrafoveal schisis within the outer and inner nuclear and ganglion cell layer, alone or in combination. Photoreceptor outer and inner segment layers were disrupted and irregular in all patients. CONCLUSIONS Retinal dystrophy in XLRS is reflected by morphological changes within the inner and outer retinal layers. Disturbed foveal photoreceptor integrity was identified in all patients. Retinal layer abnormalities correlated with age but did not appear to correlate with visual acuity or genotypic variation.
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Affiliation(s)
- Christina Gerth
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
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Janssen A, Min SH, Molday LL, Tanimoto N, Seeliger MW, Hauswirth WW, Molday RS, Weber BHF. Effect of Late-stage Therapy on Disease Progression in AAV-mediated Rescue of Photoreceptor Cells in the Retinoschisin-deficient Mouse. Mol Ther 2008; 16:1010-7. [DOI: 10.1038/mt.2008.57] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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Audo I, Robson AG, Holder GE, Moore AT. The negative ERG: clinical phenotypes and disease mechanisms of inner retinal dysfunction. Surv Ophthalmol 2008; 53:16-40. [PMID: 18191655 DOI: 10.1016/j.survophthal.2007.10.010] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Inner retinal dysfunction is encountered in a number of retinal disorders, either inherited or acquired, as a primary or predominant defect. Fundus examination is rarely diagnostic in these disorders, although some show characteristic features, and careful electrophysiological assessment of retinal function is needed for accurate diagnosis. The ERG in inner retinal dysfunction typically shows a negative waveform with a preserved a-wave and a selectively reduced b-wave. Advances in retinal physiology and molecular genetics have led to a greater understanding of the pathogenesis of these disorders. This review summarizes current knowledge on normal retinal physiology, the investigative techniques used and the range of clinical disorders in which there is predominantly inner retinal dysfunction.
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ERG variability in X-linked congenital retinoschisis patients with mutations in the RS1 gene and the diagnostic importance of fundus autofluorescence and OCT. Doc Ophthalmol 2007; 116:97-109. [DOI: 10.1007/s10633-007-9094-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2006] [Accepted: 10/16/2007] [Indexed: 11/27/2022]
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Holopigian K, Wynn P, Seiple W, Carr RE, Hood DC. Eccentricity-dependent changes in local onset and offset responses in patients with progressive cone dystrophy. Vision Res 2007; 47:2297-304. [PMID: 17614114 DOI: 10.1016/j.visres.2007.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 04/19/2007] [Accepted: 05/18/2007] [Indexed: 11/19/2022]
Abstract
Shinoda and colleagues hypothesized that patients with cone dystrophy (CD) might suffer from a selective ON-system deficit, based on the local nature of the disease [Shinoda, K, Ohde, H, Inoue, R, Ishida, S, Mashima, Y, & Oguchi, Y (2002). ON-pathway disturbance in two siblings. Acta Ophthalmologica Scandinavica, 80, 219-223]. The purpose of the current study was to test this hypothesis by examining onset and offset responses as a function of eccentricity in a group of patients with CD using long-duration LED stimuli. Nine patients with CD participated in this study (mean age of 36.1 years and visual acuity 20/200). For this study, the following measures were obtained: Humphrey threshold visual fields, standard multifocal ERGs (mfERGs) as well as mfERGs to long duration stimuli recorded using the Retiscan stimulator (Roland Instruments). This display contained 61 scaled hexagons and the LEDs were on for 100ms (180cd/m(2)) and off for 100ms. In addition, standard full-field photopic and flicker ERGs using Ganzfeld stimulation were obtained. For the control subjects, the onset responses were larger than the offset responses at all eccentricities; whereas for the patients, there was overlap between the amplitudes of the onset and offset responses. For the patients, the amplitude ratios (relative to the control data) indicated that the difference between the onset and offset responses was greatest for the central-most ring and this difference decreased with increasing eccentricity. For the onset responses, Humphrey thresholds and mfERG amplitudes, performance was poorest for the center ring and best for the most peripheral ring; for the offset responses, the opposite pattern of results was obtained. The differences in the pattern of results in the long duration mfERG data are consistent with a selective loss of the onset responses in our patient population.
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Affiliation(s)
- K Holopigian
- Department of Ophthalmology, New York University School of Medicine, BEL 5N15, 462 First Avenue, New York, NY 10016, USA.
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