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Tu Z, Degg C, Bach M, McLean R, Sheth V, Thomas MG, Yang S, Gottlob I, Proudlock FA. ERG Responses in Albinism, Idiopathic Infantile Nystagmus, and Controls. Invest Ophthalmol Vis Sci 2024; 65:11. [PMID: 38573619 PMCID: PMC10996992 DOI: 10.1167/iovs.65.4.11] [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: 08/01/2023] [Accepted: 03/04/2024] [Indexed: 04/05/2024] Open
Abstract
Purpose Our primary aim was to compare adult full-field ERG (ffERG) responses in albinism, idiopathic infantile nystagmus (IIN), and controls. A secondary aim was to investigate the effect of within-subject changes in nystagmus eye movements on ffERG responses. Methods Dilated Ganzfeld flash ffERG responses were recorded using DTL electrodes under conditions of dark (standard and dim flash) and light adaptation in 68 participants with albinism, 43 with IIN, and 24 controls. For the primary aim, the effect of group and age on ffERG responses was investigated. For the secondary aim, null region characteristics were determined using eye movements recorded prior to ffERG recordings. ffERG responses were recorded near and away from the null regions of 18 participants also measuring the success rate of recordings. Results For the primary aim, age-adjusted photopic a- and b-wave amplitudes were consistently smaller in IIN compared with controls (P < 0.0001), with responses in both groups decreasing with age. In contrast, photopic a-wave amplitudes increased with age in albinism (P = 0.0035). For the secondary aim, more intense nystagmus significantly reduced the success rate of measurable responses. Within-subject changes in nystagmus intensity generated small, borderline significant differences in photopic b-wave peak times and a-and b-wave amplitudes under scotopic conditions with standard flash. Conclusions Age-adjusted photopic ffERG responses are significantly reduced in IIN adding to the growing body of evidence of retinal abnormalities in IIN. Differences between photopic responses in albinism and controls depend on age. Success at obtaining ffERG responses could be improved by recording responses at the null region.
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Affiliation(s)
- Zhanhan Tu
- University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Christopher Degg
- Medical Physics and Clinical Engineering, Nottingham University Hospitals NHS Trust, United Kingdom
| | - Michael Bach
- Eye Center, Freiburg University, Killianstraße 5, Freiburg, Germany
| | - Rebecca McLean
- University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Viral Sheth
- University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Mervyn G. Thomas
- University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Shangqing Yang
- Gonville and Caius College, University of Cambridge, Cambridge, United Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
- Cooper University Hospital, Camden, United States
| | - Frank A. Proudlock
- University of Leicester Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
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2
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Su Y, Zhang J, Gao J, Ding G, Jiang H, Liu Y, Li Y, Yang G. Truncated FRMD7 proteins in congenital Nystagmus: novel frameshift mutations and proteasomal pathway implications. BMC Med Genomics 2024; 17:36. [PMID: 38279119 PMCID: PMC10811807 DOI: 10.1186/s12920-024-01817-7] [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: 11/01/2023] [Accepted: 01/23/2024] [Indexed: 01/28/2024] Open
Abstract
Idiopathic congenital nystagmus (ICN) manifests as involuntary and periodic eye movements. To identify the genetic defect associated with X-linked ICN, Whole Exome Sequencing (WES) was conducted in two affected families. We identified two frameshift mutations in FRMD7, c.1492dupT/p.(Y498Lfs*15) and c.1616delG/p.(R539Kfs*2). Plasmids harboring the mutated genes and qPCR analysis revealed mRNA stability, evading degradation via the NMD pathway, and corroborated truncated protein production via Western-blot analysis. Notably, both truncated proteins were degraded through the proteasomal (ubiquitination) pathway, suggesting potential therapeutic avenues targeting this pathway for similar mutations. Moreover, we conducted a comprehensive analysis, summarizing 140 mutations within the FRMD7 gene. Our findings highlight the FERM and FA structural domains as mutation-prone regions. Interestingly, exons 9 and 12 are the most mutated regions, but 90% (28/31) mutations in exon 9 are missense while 84% (21/25) mutations in exon 12 are frameshift. A predominant occurrence of shift code mutations was observed in exons 11 and 12, possibly associated with the localization of premature termination codons (PTCs), leading to the generation of deleterious truncated proteins. Additionally, our conjecture suggests that the loss of FRMD7 protein function might not solely drive pathology; rather, the emergence of aberrant protein function could be pivotal in nystagmus etiology. We propose a dependence of FRMD7 protein normal function primarily on its anterior domain. Future investigations are warranted to validate this hypothesis.
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Affiliation(s)
- Yuqing Su
- Department of Medical Genetics, School of Basic Medical Science, Wuhan University, Wuhan, China
- The First Clinical College of Wuhan University, Wuhan, China
| | - Juntao Zhang
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, 441021, China
| | - Jiahui Gao
- Department of Medical Genetics, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Guoqing Ding
- Department of Medical Genetics, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Heng Jiang
- Department of Medical Genetics, School of Basic Medical Science, Wuhan University, Wuhan, China
| | - Yang Liu
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, 441021, China
| | - Yulei Li
- Xiangyang Central Hospital, Affiliated Hospital of Hubei University of Arts and Science, Xiangyang, 441021, China.
- School of Basic Medicine, Hubei University of Arts and Science, Xiangyang, 441053, China.
| | - Guohua Yang
- Department of Medical Genetics, School of Basic Medical Science, Wuhan University, Wuhan, China.
- Hubei Provincial Key Laboratory of Developmentally Originated Disease, Wuhan, 430071, China.
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Rodwell V, Patil M, Kuht HJ, Neuhauss SCF, Norton WHJ, Thomas MG. Zebrafish Optokinetic Reflex: Minimal Reporting Guidelines and Recommendations. BIOLOGY 2023; 13:4. [PMID: 38275725 PMCID: PMC10813647 DOI: 10.3390/biology13010004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 12/14/2023] [Accepted: 12/18/2023] [Indexed: 01/27/2024]
Abstract
Optokinetic reflex (OKR) assays in zebrafish models are a valuable tool for studying a diverse range of ophthalmological and neurological conditions. Despite its increasing popularity in recent years, there are no clear reporting guidelines for the assay. Following reporting guidelines in research enhances reproducibility, reduces bias, and mitigates underreporting and poor methodologies in published works. To better understand optimal reporting standards for an OKR assay in zebrafish, we performed a systematic literature review exploring the animal, environmental, and technical factors that should be considered. Using search criteria from three online databases, a total of 109 research papers were selected for review. Multiple crucial factors were identified, including larval characteristics, sample size, fixing method, OKR set-up, distance of stimulus, detailed stimulus parameters, eye recording, and eye movement analysis. The outcome of the literature analysis highlighted the insufficient information provided in past research papers and the lack of a systematic way to present the parameters related to each of the experimental factors. To circumvent any future errors and champion robust transparent research, we have created the zebrafish optokinetic (ZOK) reflex minimal reporting guideline.
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Affiliation(s)
- Vanessa Rodwell
- Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Leicester LE1 7RH, UK
| | - Manjiri Patil
- Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Leicester LE1 7RH, UK
| | - Helen J. Kuht
- Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Leicester LE1 7RH, UK
| | | | - William H. J. Norton
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Mervyn G. Thomas
- Ulverscroft Eye Unit, School of Psychology and Vision Sciences, University of Leicester, Leicester LE1 7RH, UK
- Department of Ophthalmology, University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary, Leicester LE1 5WW, UK
- Department of Clinical Genetics, University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary, Leicester LE1 5WW, UK
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4
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Hafdaoui S, Ciaccio C, Castellotti B, Sciacca FL, Pantaleoni C, D'Arrigo S. Case report: A novel pathogenic FRMD7 variant in a Turner syndrome patient with familial idiopathic infantile nystagmus. Front Neurol 2023; 14:1199095. [PMID: 37545716 PMCID: PMC10398378 DOI: 10.3389/fneur.2023.1199095] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Accepted: 06/28/2023] [Indexed: 08/08/2023] Open
Abstract
Infantile idiopathic nystagmus (IIN) is an oculomotor disorder characterized by involuntary bilateral, periodic ocular oscillations, predominantly on the horizontal axis. X-linked IIN (XLIIN) is the most common form of congenital nystagmus, and the FERM domain-containing gene (FRMD7) is the most common cause of pathogenesis, followed by mutations in GPR143. To date, more than 60 pathogenic FRMD7 variants have been identified, and the physiopathological pathways leading to the disease are not yet completely understood. FRMD7-associated nystagmus usually affects male patients, while it shows incomplete penetrance in female patients, who are mostly asymptomatic but sometimes present with mild ocular oscillations or, occasionally, with clear nystagmus. Here we report the first case of a patient with Turner syndrome and INN in an XLIIN pedigree, in which we identified a novel frameshift mutation (c.1492dupT) in the FRMD7 gene: the absence of one X chromosome in the patient unmasked the presence of the familial genetic nystagmus.
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Affiliation(s)
- Sara Hafdaoui
- Department of Pediatric Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Claudia Ciaccio
- Department of Pediatric Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Barbara Castellotti
- Department of Medical Genetics and Neurogenetics, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Francesca L. Sciacca
- Laboratory of Cytogenetic, Neurological Biochemistry and Neuropharmacology Unit, Department of Diagnostic and Technology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Chiara Pantaleoni
- Department of Pediatric Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Stefano D'Arrigo
- Department of Pediatric Neurosciences, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
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5
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Arshad MW, Shabbir MI, Asif S, Shahzad M, Leydier L, Rai SK. FRMD7 Gene Alterations in a Pakistani Family Associated with Congenital Idiopathic Nystagmus. Genes (Basel) 2023; 14:genes14020346. [PMID: 36833273 PMCID: PMC9957179 DOI: 10.3390/genes14020346] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2022] [Revised: 01/27/2023] [Accepted: 01/27/2023] [Indexed: 01/31/2023] Open
Abstract
Congenital idiopathic nystagmus (CIN) is an oculomotor disorder characterized by repetitive and rapid involuntary movement of the eye that usually develops in the first six months after birth. Unlike other forms of nystagmus, CIN is widely associated with mutations in the FRMD7 gene. This study involves the molecular genetic analysis of a consanguineous Pakistani family with individuals suffering from CIN to undermine any potential pathogenic mutations. Blood samples were taken from affected and normal individuals of the family. Genomic DNA was extracted using an in-organic method. Whole Exome Sequencing (WES) and analysis were performed to find any mutations in the causative gene. To validate the existence and co-segregation of the FRMD7 gene variant found using WES, sanger sequencing was also carried out using primers that targeted all of the FRMD7 coding exons. Additionally, the pathogenicity of the identified variant was assessed using different bioinformatic tools. The WES results identified a novel nonsense mutation in the FRMD7 (c.443T>A; p. Leu148 *) gene in affected individuals from the Pakistani family, with CIN resulting in a premature termination codon, further resulting in the formation of a destabilized protein structure that was incomplete. Co-segregation analysis revealed that affected males are hemizygous for the mutated allele c.443T>A; p. Leu148 * and the affected mother is heterozygous. Overall, such molecular genetic studies expand our current knowledge of the mutations associated with the FRMD7 gene in Pakistani families with CIN and significantly enhance our understanding of the molecular mechanisms involved in genetic disorders.
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Affiliation(s)
- Muhammad Waqar Arshad
- Department of Psychiatry, Yale School of Medicine, VA CT Healthcare Center S116A2, West Haven, CT 06516, USA
- Department of Molecular Biology, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad 44080, Pakistan
| | - Muhammad Imran Shabbir
- Department of Biological Sciences, Faculty of Basic & Applied Sciences, International Islamic University, Sector H-10, Islamabad 44000, Pakistan
- Correspondence: (M.I.S.); (S.K.R.)
| | - Saaim Asif
- Department of Biological Sciences, Faculty of Basic & Applied Sciences, International Islamic University, Sector H-10, Islamabad 44000, Pakistan
- Department of Biosciences, COMSATS University Islamabad, Islamabad Campus, Islamabad 45550, Pakistan
| | - Mohsin Shahzad
- Department of Molecular Biology, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad 44080, Pakistan
| | - Larissa Leydier
- Department of Molecular Biology, Medical University of the Americas, Charlestown KN 1102, Saint Kitts and Nevis, West Indies
| | - Sunil Kumar Rai
- Department of Molecular Biology, Medical University of the Americas, Charlestown KN 1102, Saint Kitts and Nevis, West Indies
- Correspondence: (M.I.S.); (S.K.R.)
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6
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Lee J, Jeong H, Won D, Shin S, Lee ST, Choi JR, Byeon SH, Kuht HJ, Thomas MG, Han J. Noncanonical Splice Site and Deep Intronic FRMD7 Variants Activate Cryptic Exons in X-linked Infantile Nystagmus. Transl Vis Sci Technol 2022; 11:25. [PMID: 35762937 PMCID: PMC9251792 DOI: 10.1167/tvst.11.6.25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Purpose We aim to report noncoding pathogenic variants in patients with FRMD7-related infantile nystagmus (FIN). Methods Genome sequencing (n = 2 families) and reanalysis of targeted panel next generation sequencing (n = 2 families) was performed in genetically unsolved cases of suspected FIN. Previous sequence analysis showed no pathogenic coding variants in genes associated with infantile nystagmus. SpliceAI, SpliceRover, and Alamut consensus programs were used to annotate noncoding variants. Minigene splicing assay was performed to confirm aberrant splicing. In silico analysis of exonic splicing enhancer and silencer was also performed. Results FRMD7 intronic variants were identified based on genome sequencing and targeted next-generation sequencing analysis. These included c.285-12A>G (pedigree 1), c.284+63T>A (pedigrees 2 and 3), and c. 383-1368A>G (pedigree 4). All variants were absent in gnomAD, and the both c.285-12A>G and c.284+63T>A variants were predicted to enhance new splicing acceptor gains with SpliceAI, SpliceRover, and Alamut consensus approaches. However, the c.383-1368 A>G variant only had a significant impact score on the SpliceRover program. The c.383-1368A>G variant was predicted to promote pseudoexon inclusion by binding of exonic splicing enhancer. Aberrant exonizations were validated through minigene constructs, and all variants were segregated in the families. Conclusions Deep learning–based annotation of noncoding variants facilitates the discovery of hidden genetic variations in patients with FIN. This study provides evidence of effectiveness of combined deep learning–based splicing tools to identify hidden pathogenic variants in previously unsolved patients with infantile nystagmus. Translational Relevance These results demonstrate robust analysis using two deep learning splicing predictions and in vitro functional study can lead to finding hidden genetic variations in unsolved patients.
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Affiliation(s)
- Junwon Lee
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Han Jeong
- Brain Korea 21 Project for Medical Science, Yonsei University, Seoul, South Korea.,Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Dongju Won
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Saeam Shin
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.,Dxome Co., Ltd. Seongnam-si, Gyeonggi-do, South Korea
| | - Jong Rak Choi
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea.,Dxome Co., Ltd. Seongnam-si, Gyeonggi-do, South Korea
| | - Suk Ho Byeon
- Brain Korea 21 Project for Medical Science, Yonsei University, Seoul, South Korea.,Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
| | - Helen J Kuht
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Mervyn G Thomas
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, South Korea
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7
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Kuht HJ, Maconachie GDE, Han J, Kessel L, van Genderen MM, McLean RJ, Hisaund M, Tu Z, Hertle RW, Gronskov K, Bai D, Wei A, Li W, Jiao Y, Smirnov V, Choi JH, Tobin MD, Sheth V, Purohit R, Dawar B, Girach A, Strul S, May L, Chen FK, Heath Jeffery RC, Aamir A, Sano R, Jin J, Brooks BP, Kohl S, Arveiler B, Montoliu L, Engle EC, Proudlock FA, Nishad G, Pani P, Varma G, Gottlob I, Thomas MG. Genotypic and Phenotypic Spectrum of Foveal Hypoplasia: A Multicenter Study. Ophthalmology 2022; 129:708-718. [PMID: 35157951 PMCID: PMC9341240 DOI: 10.1016/j.ophtha.2022.02.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To characterize the genotypic and phenotypic spectrum of foveal hypoplasia (FH). DESIGN Multicenter, observational study. PARTICIPANTS A total of 907 patients with a confirmed molecular diagnosis of albinism, PAX6, SLC38A8, FRMD7, AHR, or achromatopsia from 12 centers in 9 countries (n = 523) or extracted from publicly available datasets from previously reported literature (n = 384). METHODS Individuals with a confirmed molecular diagnosis and availability of foveal OCT scans were identified from 12 centers or from the literature between January 2011 and March 2021. A genetic diagnosis was confirmed by sequence analysis. Grading of FH was derived from OCT scans. MAIN OUTCOME MEASURES Grade of FH, presence or absence of photoreceptor specialization (PRS+ vs. PRS-), molecular diagnosis, and visual acuity (VA). RESULTS The most common genetic etiology for typical FH in our cohort was albinism (67.5%), followed by PAX6 (21.8%), SLC38A8 (6.8%), and FRMD7 (3.5%) variants. AHR variants were rare (0.4%). Atypical FH was seen in 67.4% of achromatopsia cases. Atypical FH in achromatopsia had significantly worse VA than typical FH (P < 0.0001). There was a significant difference in the spectrum of FH grades based on the molecular diagnosis (chi-square = 60.4, P < 0.0001). All SLC38A8 cases were PRS- (P = 0.003), whereas all FRMD7 cases were PRS+ (P < 0.0001). Analysis of albinism subtypes revealed a significant difference in the grade of FH (chi-square = 31.4, P < 0.0001) and VA (P = 0.0003) between oculocutaneous albinism (OCA) compared with ocular albinism (OA) and Hermansky-Pudlak syndrome (HPS). Ocular albinism and HPS demonstrated higher grades of FH and worse VA than OCA. There was a significant difference (P < 0.0001) in VA between FRMD7 variants compared with other diagnoses associated with FH. CONCLUSIONS We characterized the phenotypic and genotypic spectrum of FH. Atypical FH is associated with a worse prognosis than all other forms of FH. In typical FH, our data suggest that arrested retinal development occurs earlier in SLC38A8, OA, HPS, and AHR variants and later in FRMD7 variants. The defined time period of foveal developmental arrest for OCA and PAX6 variants seems to demonstrate more variability. Our findings provide mechanistic insight into disorders associated with FH and have significant prognostic and diagnostic value.
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Affiliation(s)
- Helen J Kuht
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom; Foveal Development Investigators Group
| | - Gail D E Maconachie
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom; Academic Unit of Ophthalmology and Orthoptics, University of Sheffield, Sheffield, United Kingdom; Foveal Development Investigators Group
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea; Foveal Development Investigators Group
| | - Line Kessel
- Department of Ophthalmology, Rigshospitalet, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Foveal Development Investigators Group
| | - Maria M van Genderen
- Department of Ophthalmology, University Medical Centre Utrecht, Utrecht, The Netherlands; Bartiméus Diagnostic Centre for Complex Visual Disorders, Zeist, The Netherlands; Foveal Development Investigators Group
| | - Rebecca J McLean
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Michael Hisaund
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Zhanhan Tu
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom; Foveal Development Investigators Group
| | - Richard W Hertle
- Department of Ophthalmology, The Rebecca D. Considine Research Institute and The Children's Vision Center, Akron Children's Hospital, Akron, Ohio; Department of Surgery, The Northeastern Ohio Medical University, Rootstown, Ohio; Foveal Development Investigators Group
| | - Karen Gronskov
- Department of Clinical Genetics, Rigshospitalet-Kennedy Center, Glostrup, Denmark; Foveal Development Investigators Group
| | - Dayong Bai
- Department of Ophthalmology, Beijing Children's Hospital, National Center for Children's Health, Capital Medical University, Beijing, China; Foveal Development Investigators Group
| | - Aihua Wei
- Department of Dermatology, Beijing Tongren Hospital, Capital Medical University, Beijing, China; Foveal Development Investigators Group
| | - Wei Li
- Beijing Key Laboratory for Genetics of Birth Defects, Beijing Pediatric Research Institute; Rare Disease Center, National Center for Children's Health; MOE Key Laboratory of Major Diseases in Children, Beijing Children's Hospital, Capital Medical University, Beijing, China; Foveal Development Investigators Group
| | - Yonghong Jiao
- Beijing Tongren Eye Centre, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Science Key Lab, Beijing, China; Foveal Development Investigators Group
| | - Vasily Smirnov
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la Vision, Paris, France; Exploration de la Vision et Neuro-Ophtalmologie, CHU de Lille, Lille, France; Foveal Development Investigators Group
| | - Jae-Hwan Choi
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea; Foveal Development Investigators Group
| | - Martin D Tobin
- Department of Health Sciences, University of Leicester, Leicester, United Kingdom; Foveal Development Investigators Group
| | - Viral Sheth
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom; Academic Unit of Ophthalmology and Orthoptics, University of Sheffield, Sheffield, United Kingdom
| | - Ravi Purohit
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Basu Dawar
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Ayesha Girach
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Sasha Strul
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota; Foveal Development Investigators Group
| | - Laura May
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota; Foveal Development Investigators Group
| | - Fred K Chen
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Crawley, Australia; Foveal Development Investigators Group
| | - Rachael C Heath Jeffery
- Centre for Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Crawley, Australia; Foveal Development Investigators Group
| | - Abdullah Aamir
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Ronaldo Sano
- Retina and Vitreous Sector of Santa Casa de Misericórdia de São Paulo, São Paulo, Brazil; Foveal Development Investigators Group
| | - Jing Jin
- Sidney Kimmel Medical College of Thomas Jefferson University, Nemours Children's Health, Philadelphia, Pennsylvania; Nemours Children's Health, Wilmington, Delaware
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland; Foveal Development Investigators Group
| | - Susanne Kohl
- Centre for Ophthalmology, Institute for Ophthalmic Research, University Tübingen, Tübingen, Germany; Foveal Development Investigators Group
| | - Benoit Arveiler
- Rare Diseases, Genetics and Metabolism, INSERM U1211, University of Bordeaux, Bordeaux, France; Molecular Genetics Laboratory, Bordeaux University Hospital, Bordeaux, France; Foveal Development Investigators Group
| | - Lluis Montoliu
- National Centre for Biotechnology (CNB-CSIC) and CIBERER-ISCIII, Madrid, Spain; Foveal Development Investigators Group
| | - Elizabeth C Engle
- Departments of Neurology and Ophthalmology, Boston Children's Hospital and Harvard Medical School, Boston, Massachusetts; Howard Hughes Medical Institute, Chevy Chase, Maryland; Foveal Development Investigators Group
| | - Frank A Proudlock
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom
| | - Garima Nishad
- International Institute of Information Technology, Hyderabad, India
| | - Prateek Pani
- International Institute of Information Technology, Hyderabad, India
| | - Girish Varma
- International Institute of Information Technology, Hyderabad, India; Foveal Development Investigators Group
| | - Irene Gottlob
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom; Foveal Development Investigators Group; Cooper Neurological Institute, Cooper Medical School of Rowan University, Camden, New Jersey
| | - Mervyn G Thomas
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, United Kingdom; Foveal Development Investigators Group.
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8
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Galvez-Ruiz A, Galindo-Ferreiro A, Lehner AJ. A new gene mutation in a family with idiopathic infantile nystagmus. Saudi J Ophthalmol 2021; 35:61-65. [PMID: 34667935 PMCID: PMC8486036 DOI: 10.4103/1319-4534.325787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 01/20/2021] [Accepted: 01/30/2021] [Indexed: 12/04/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is an inherited disease, which can occur through a number of different inheritance patterns (autosomal dominant, recessive, or X-linked). The most common of these is X-linked inheritance with incomplete penetrance and variable expressivity, and can also be dominant or recessive. To date, only two mutations have been described: the first, affecting the FPR143 gene, which is associated with ocular albinism type I, and located on chromosome Xp22, and the second, affecting the FRMD7 gene located on chromosome X26-q27. To date, a causative gene on locus Xp11.3p11.4 has not yet been identified. The most common cause of IIN is due to mutations in the FRMD7 gene, located on chromosome Xq26. We present a case of a new mutation found in three siblings from a family with FRMD7-related infantile nystagmus, whose parents are consanguineously related in the first degree. A complex mutation has occurred in this family, which, to date, has not been previously reported in the scientific literature. The complex mutation consists of the presence of three consecutive 1 bp deletions in exon 12 (c.1248delT; 1299del C; and 1312delT), causing a secondary deletion (c. 1340–2145 + 214del), and resulting in a truncated protein. We also present a 7-year-old patient from a different family, with periodic alternating nystagmus, having no mutation in the FRMD7 gene, which we assume may be an example of non-FRMD7-related IIN. This patient does not have a family history of nystagmus.
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Affiliation(s)
- Alberto Galvez-Ruiz
- Neuro-ophthalmology Division, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | | | - Anthony J Lehner
- Orthoptics Division, Clinical Orthoptist, Vision Eye Institute, University of Sydney, New South Wales, Australia.,Orthoptics Division, Save Sight Institute, University of Sydney, New South Wales, Australia
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9
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Dawar B, Kuht HJ, Han J, Maconachie GDE, Thomas MG. Clinical utility gene card for FRMD7-related infantile nystagmus. Eur J Hum Genet 2021; 29:1584-1588. [PMID: 33633368 PMCID: PMC8484540 DOI: 10.1038/s41431-021-00826-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 12/29/2020] [Accepted: 01/24/2021] [Indexed: 02/07/2023] Open
Affiliation(s)
- Basu Dawar
- grid.9918.90000 0004 1936 8411Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX UK
| | - Helen J. Kuht
- grid.9918.90000 0004 1936 8411Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX UK
| | - Jinu Han
- grid.15444.300000 0004 0470 5454Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
| | - Gail D. E. Maconachie
- grid.9918.90000 0004 1936 8411Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX UK ,grid.11835.3e0000 0004 1936 9262Division of Ophthalmology and Orthoptics, Health Sciences School, University of Sheffield, Sheffield, UK
| | - Mervyn G. Thomas
- grid.9918.90000 0004 1936 8411Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, RKCSB, PO Box 65, Leicester, LE2 7LX UK
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10
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Choi JH, Kim SJ, Thomas MG, Jung JH, Oh EH, Shin JH, Cho JW, Kim HS, Park JY, Choi SY, Choi HY, Choi KD. Diagnostic yield of targeted next-generation sequencing in infantile nystagmus syndrome. Ophthalmic Genet 2021; 42:561-569. [PMID: 34132631 DOI: 10.1080/13816810.2021.1938138] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Background: Infantile nystagmus syndrome (INS) is a genetically heterogeneous disorder. Identifying genetic causes of INS would help clinicians to facilitate clinical diagnosis and provide appropriate treatment. The aim of this study was to determine the diagnostic utility of targeted next-generation sequencing (NGS) for INS.Materials and methods: We recruited 37 patients who were referred to the Neuro-ophthalmology clinics for evaluations of INS. NGS was performed using a targeted panel that included 98 candidate genes associated with INS. We identified pathogenic variants according to guidelines of the American College of Medical Genetics and Genomics. We also calculated the sensitivity and specificity of each clinical sign to assess the diagnostic yield of our gene panel.Results: After variant filtering, annotation, and interpretation, the potential pathogenic variants were detected in 13 of the 37 patients, achieving a molecular diagnostic rate of 35%. The identified genes were PAX6 (n = 4), FRMD7 (n = 4), GPR143 (n = 2), CACNA1F (n = 1), CNGA3 (n = 1) and GUCY2D (n = 1). In approximately 30% (n = 4) of the patients, the initial clinical diagnosis was revised after a molecular diagnosis was performed. The presence of a family history had the highest predictive power for a molecular diagnosis (sensitivity = 61.5%, specificity = 91.7%), and the sensitivity increased when the family history was considered together with one of two clinical signs such as pendular nystagmus waveforms or anterior segment dysgenesis.Conclusions: Our study shows that targeted NGS can be useful to determine a molecular diagnosis for patients with INS. Targeted NGS also helps to confirm a clinical diagnosis in atypical phenotypes or unresolved cases.
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Affiliation(s)
- Jae-Hwan Choi
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Su-Jin Kim
- Department of Ophthalmology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Mervyn G Thomas
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Jae-Ho Jung
- Department of Ophthalmology, Seoul National University Hospital, Seoul, Korea
| | - Eun Hye Oh
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jae Wook Cho
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Hyang-Sook Kim
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Ji-Yun Park
- Department of Neurology, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea
| | - Seo Young Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, Korea
| | - Hee Young Choi
- Department of Ophthalmology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, Korea
| | - Kwang-Dong Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, Korea
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11
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Discordant phenotypes in twins with infantile nystagmus. Sci Rep 2021; 11:2826. [PMID: 33531592 PMCID: PMC7854608 DOI: 10.1038/s41598-021-82368-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 01/18/2021] [Indexed: 11/08/2022] Open
Abstract
Infantile nystagmus (IN) may result from aetiologies including albinism and FRMD7 mutations. IN has low prevalence, and twins with IN are rare. Whilst discordant presentation has been previously reported for IN, we present for the first time the comprehensive assessment of diagnostically discordant monozygotic twins. From a cohort of over 2000 patients, we identified twins and triplets discordant for nystagmus. Using next-generation sequencing, high-resolution infra-red pupil tracking and optical coherence tomography, we characterised differences in genotype and phenotype. Monozygotic twins (n = 1), dizygotic twins (n = 3) and triplets (n = 1) were included. The monozygotic twins had concordant TYR variants. No causative variants were identified in the triplets. Dizygotic twins had discordant variants in TYR, OCA2 and FRMD7. One unaffected co-twin demonstrated sub-clinical nystagmus. Foveal hypoplasia (FH) was noted in four of five probands. Both co-twins of the monozygotic pair and triplets displayed FH. In three families, at least one parent had FH without nystagmus. FH alone may be insufficient to develop nystagmus. Whilst arrested optokinetic reflex pathway development is implicated in IN, discordant twins raise questions regarding where differences in development have arisen. In unaffected monozygotes therefore, genetic variants may predispose to oculomotor instability, with variable expressivity possibly responsible for the discordance observed.
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12
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Papageorgiou E, Gottlob I. The challenges faced by clinicians diagnosing and treating infantile nystagmus Part I: diagnosis. EXPERT REVIEW OF OPHTHALMOLOGY 2020. [DOI: 10.1080/17469899.2021.1860754] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Eleni Papageorgiou
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, University of Leicester, Leicester, UK
- Department of Ophthalmology, University Hospital of Larissa, Larissa, Greece
| | - Irene Gottlob
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, University of Leicester, Leicester, UK
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13
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Kuht HJ, Han J, Maconachie GDE, Park SE, Lee ST, McLean R, Sheth V, Hisaund M, Dawar B, Sylvius N, Mahmood U, Proudlock FA, Gottlob I, Lim HT, Thomas MG. SLC38A8 mutations result in arrested retinal development with loss of cone photoreceptor specialization. Hum Mol Genet 2020; 29:2989-3002. [PMID: 32744312 PMCID: PMC7645707 DOI: 10.1093/hmg/ddaa166] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 01/09/2023] Open
Abstract
Foveal hypoplasia, optic nerve decussation defects and anterior segment dysgenesis is an autosomal recessive disorder arising from SLC38A8 mutations. SLC38A8 is a putative glutamine transporter with strong expression within the photoreceptor layer in the retina. Previous studies have been limited due to lack of quantitative data on retinal development and nystagmus characteristics. In this multi-centre study, a custom-targeted next generation sequencing (NGS) gene panel was used to identify SLC38A8 mutations from a cohort of 511 nystagmus patients. We report 16 novel SLC38A8 mutations. The sixth transmembrane domain is most frequently disrupted by missense SLC38A8 mutations. Ninety percent of our cases were initially misdiagnosed as PAX6-related phenotype or ocular albinism prior to NGS. We characterized the retinal development in vivo in patients with SLC38A8 mutations using high-resolution optical coherence tomography. All patients had severe grades of arrested retinal development with lack of a foveal pit and no cone photoreceptor outer segment lengthening. Loss of foveal specialization features such as outer segment lengthening implies reduced foveal cone density, which contributes to reduced visual acuity. Unlike other disorders (such as albinism or PAX6 mutations) which exhibit a spectrum of foveal hypoplasia, SLC38A8 mutations have arrest of retinal development at an earlier stage resulting in a more under-developed retina and severe phenotype.
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Affiliation(s)
- Helen J Kuht
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea
| | - Gail D E Maconachie
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
- Academic Unit of Ophthalmology and Orthoptics, University of Sheffield, Sheffield S10 2RX, UK
| | - Sung Eun Park
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea
| | - Seung-Tae Lee
- Department of Laboratory Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea
| | - Rebecca McLean
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Viral Sheth
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Michael Hisaund
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Basu Dawar
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Nicolas Sylvius
- Department of Genetics and Genome Biology, University of Leicester, Leicester LE1 7RH, UK
| | - Usman Mahmood
- Department of Ophthalmology, Hull and East Yorkshire Hospitals NHS Trust, Hull HU3 2JZ, UK
| | - Frank A Proudlock
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Irene Gottlob
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Hyun Taek Lim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Mervyn G Thomas
- The University of Leicester Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester – RKCSB, PO Box 65, Leicester LE2 7LX, UK
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14
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Salman A, Hutton SB, Newall T, Scott JA, Griffiths HL, Lee H, Gomez-Nicola D, Lotery AJ, Self JE. Characterization of the Frmd7 Knock-Out Mice Generated by the EUCOMM/COMP Repository as a Model for Idiopathic Infantile Nystagmus (IIN). Genes (Basel) 2020; 11:genes11101157. [PMID: 33007925 PMCID: PMC7601595 DOI: 10.3390/genes11101157] [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: 08/18/2020] [Revised: 09/21/2020] [Accepted: 09/24/2020] [Indexed: 12/30/2022] Open
Abstract
In this study, we seek to exclude other pathophysiological mechanisms by which Frmd7 knock-down may cause Idiopathic Infantile Nystagmus (IIN) using the Frmd7.tm1a and Frmd7.tm1b murine models. We used a combination of genetic, histological and visual function techniques to characterize the role of Frmd7 gene in IIN using a novel murine model for the disease. We demonstrate that the Frmd7.tm1b allele represents a more robust model of Frmd7 knock-out at the mRNA level. The expression of Frmd7 was investigated using both antibody staining and X-gal staining confirming previous reports that Frmd7 expression in the retina is restricted to starburst amacrine cells and demonstrating that X-gal staining recapitulates the expression pattern in this model. Thus, it offers a useful tool for further expression studies. We also show that gross retinal morphology and electrophysiology are unchanged in these Frmd7 mutant models when compared with wild-type mice. High-speed eye-tracking recordings of Frmd7 mutant mice confirm a specific horizontal optokinetic reflex defect. In summary, our study confirms the likely role for Frmd7 in the optokinetic reflex in mice mediated by starburst amacrine cells. We show that the Frmd7.tm1b model provides a more robust knock-out than the Frmd7.tm1a model at the mRNA level, although the functional consequence is unchanged. Finally, we establish a robust eye-tracking technique in mice that can be used in a variety of future studies using this model and others. Although our data highlight a deficit in the optiokinetic reflex as a result of the starburst amacrine cells in the retina, this does not rule out the involvement of other cells, in the brain or the retina where Frmd7 is expressed, in the pathophysiology of IIN.
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MESH Headings
- Alleles
- Amacrine Cells/metabolism
- Animals
- Cytoskeletal Proteins/genetics
- Cytoskeletal Proteins/metabolism
- Disease Models, Animal
- Electroretinography
- Female
- Gene Expression
- Genetic Diseases, X-Linked/genetics
- Genetic Diseases, X-Linked/pathology
- Genetic Diseases, X-Linked/physiopathology
- Male
- Mice
- Mice, Knockout
- Mutation
- Nystagmus, Congenital/genetics
- Nystagmus, Congenital/pathology
- Nystagmus, Congenital/physiopathology
- Nystagmus, Optokinetic
- Retina/metabolism
- Retina/pathology
- Retina/physiopathology
- Tomography, Optical Coherence
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Affiliation(s)
- Ahmed Salman
- Clinical and Experimental Neurosciences, University of Southampton, Southampton SO16 6YD, UK; (T.N.); (J.A.S.); (H.L.G.); (H.L.); (A.J.L.); (J.E.S.)
- Correspondence:
| | - Samuel B. Hutton
- School of Psychology, University of Sussex, Brighton BN1 9QH, UK;
| | - Tutte Newall
- Clinical and Experimental Neurosciences, University of Southampton, Southampton SO16 6YD, UK; (T.N.); (J.A.S.); (H.L.G.); (H.L.); (A.J.L.); (J.E.S.)
| | - Jennifer A. Scott
- Clinical and Experimental Neurosciences, University of Southampton, Southampton SO16 6YD, UK; (T.N.); (J.A.S.); (H.L.G.); (H.L.); (A.J.L.); (J.E.S.)
| | - Helen L. Griffiths
- Clinical and Experimental Neurosciences, University of Southampton, Southampton SO16 6YD, UK; (T.N.); (J.A.S.); (H.L.G.); (H.L.); (A.J.L.); (J.E.S.)
| | - Helena Lee
- Clinical and Experimental Neurosciences, University of Southampton, Southampton SO16 6YD, UK; (T.N.); (J.A.S.); (H.L.G.); (H.L.); (A.J.L.); (J.E.S.)
| | - Diego Gomez-Nicola
- School of Biological Sciences, University of Southampton, Southampton SO171BJ, UK;
| | - Andrew J. Lotery
- Clinical and Experimental Neurosciences, University of Southampton, Southampton SO16 6YD, UK; (T.N.); (J.A.S.); (H.L.G.); (H.L.); (A.J.L.); (J.E.S.)
| | - Jay E. Self
- Clinical and Experimental Neurosciences, University of Southampton, Southampton SO16 6YD, UK; (T.N.); (J.A.S.); (H.L.G.); (H.L.); (A.J.L.); (J.E.S.)
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15
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Jiang L, Li Y, Yang K, Wang Y, Wang J, Cui X, Mao J, Gao Y, Yi P, Wang L, Liu JY. FRMD7 Mutations Disrupt the Interaction with GABRA2 and May Result in Infantile Nystagmus Syndrome. Invest Ophthalmol Vis Sci 2020; 61:41. [PMID: 32446246 PMCID: PMC7405782 DOI: 10.1167/iovs.61.5.41] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Purpose To identify the pathogenic gene of infantile nystagmus syndrome (INS) in three Chinese families and explore the potential pathogenic mechanism of FERM domain-containing 7 (FRMD7) mutations. Methods Genetic testing was performed via Sanger sequencing. Western blotting was used to analyze protein expression of FRMD7. Glutathione S-transferase pull-down and immunoprecipitation were conducted to investigate the proteins interacting with FRMD7. Rescue assays were performed in Caenorhabditis elegans to explore the potential role of FRMD7 in vivo. Results We recruited three Chinese families with X-linked INS and identified a duplication and two missense mutations in FRMD7: c.998dupA/p.His333Glnfs*2, c.580G>A/p.Ala194Thr, and c.973A>G/p.Arg325Gly (one in each family). Expression levels of three mutants were similar to that of wild-type FRMD7 in vitro. Interestingly, the mutant p.His333Glnfs*2 exhibited a predominantly nuclear location, whereas wild-type FRMD7 localized to the cytoplasm. In addition, we found FRMD7 to directly interact with the loop between transmembrane domains 3 and 4 of GABRA2, a type A gamma-aminobutyric acid (GABA) receptor (GABAARs) subunit critical for receptor transport and localization, whereas the mutants p.Ala194Thr and p.Arg325Gly exhibited decreased binding to GABRA2. In frm-3 (a nematode homologue of FRMD7) null C.elegans, we found that FRMD7 mutants exhibited a poor rescue effect on the defects of locomotion and fluorescence recovery after photobleaching of GABAARs. Conclusions Our findings identified three FRMD7 mutants in three Chinese families with X-linked INS and confirmed GABRA2 as a novel binding partner of FRMD7. These findings suggest that FRMD7 plays an important role by targeting GABAARs.
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16
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Mayer AK, Mahajnah M, Thomas MG, Cohen Y, Habib A, Schulze M, Maconachie GDE, AlMoallem B, De Baere E, Lorenz B, Traboulsi EI, Kohl S, Azem A, Bauer P, Gottlob I, Sharkia R, Wissinger B. Homozygous stop mutation in AHR causes autosomal recessive foveal hypoplasia and infantile nystagmus. Brain 2020; 142:1528-1534. [PMID: 31009037 DOI: 10.1093/brain/awz098] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 02/04/2019] [Accepted: 02/16/2019] [Indexed: 01/27/2023] Open
Abstract
Herein we present a consanguineous family with three children affected by foveal hypoplasia with infantile nystagmus, following an autosomal recessive mode of inheritance. The patients showed normal electroretinography responses, no signs of albinism, and no anterior segment or brain abnormalities. Upon whole exome sequencing, we identified a homozygous mutation (c.1861C>T;p.Q621*) in the aryl hydrocarbon receptor (AHR) gene that perfectly co-segregated with the disease in the larger family. AHR is a ligand-activated transcription factor that has been intensively studied in xenobiotic-induced toxicity. Further, it has been shown to play a physiological role under normal cellular conditions, such as in immunity, inflammatory response and neurogenesis. Notably, knockout of the Ahr gene in mouse impairs optic nerve myelin sheath formation and results in oculomotor deficits sharing many features with our patients: the eye movement disorder in Ahr-/- mice appears early in development and presents as conjugate horizontal pendular nystagmus. We therefore propose AHR to be a novel disease gene for a new, recessively inherited disorder in humans, characterized by infantile nystagmus and foveal hypoplasia.
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Affiliation(s)
- Anja K Mayer
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Muhammad Mahajnah
- Child Neurology and Development Center, Hillel-Yaffe Medical Center, Hadera, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Mervyn G Thomas
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Yuval Cohen
- The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.,Ophthalmology Department, Hillel Yaffe Medical Center, Hadera, Israel
| | - Adib Habib
- Pediatric Department, St. Vincent French Hospital, Nazareth, Israel
| | - Martin Schulze
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Gail D E Maconachie
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Basamat AlMoallem
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium.,Department of Ophthalmology, King Abdul-Aziz University Hospital, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Elfride De Baere
- Center for Medical Genetics Ghent, Ghent University and Ghent University Hospital, Ghent, Belgium
| | - Birgit Lorenz
- Department of Ophthalmology, Justus Liebig University Giessen, Giessen, Germany
| | | | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Abdussalam Azem
- Department of Biochemistry and Molecular Biology, Tel Aviv University, Tel Aviv, Israel
| | - Peter Bauer
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Irene Gottlob
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Rajech Sharkia
- The Triangle Regional Research and Development Center, Kfar Qari', Israel.,Beit-Berl Academic College, Beit-Berl, Israel
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
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17
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Wang F, Guan H, Liu W, Zhao G, Liu S. Next-generation sequencing identifies a novel frameshift variant in FRMD7 in a Chinese family with idiopathic infantile nystagmus. J Clin Lab Anal 2019; 34:e23012. [PMID: 31495972 PMCID: PMC6977136 DOI: 10.1002/jcla.23012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 07/05/2019] [Accepted: 07/26/2019] [Indexed: 01/27/2023] Open
Abstract
Background Idiopathic infantile nystagmus (IIN) is a high genetically heterogeneous ophthalmic disease and is often associated with pathogenic mutations in FRMD7 and GPR143, respectively. Idiopathic infantile nystagmus manifests as involuntary periodic rhythmic oscillation of the eyes in the very early life, which decreases visual acuity and affects the quality of life. Objective and Methods The aim of our study was to reveal a possible pathogenic variant through the investigation of a Chinese Han family with IIN with an implementation of a next‐generation sequencing method. Isolated DNA analysis was followed by Sanger sequencing validation. We also performed the detailed ophthalmological examination of family members. Results We identified a novel frameshift variant in FRMD7 (NM_194277.2: c.1419_1422dup, p.Tyr475fs), which leads to a frameshift mutation since tyrosine (Tyr) at 475 codon of FRMD7 protein (p.Tyr475fs) and co‐segregates with IIN phenotype in this family. Conclusions We found a novel frameshift FRMD7 variant in a Chinese Han family, which may be causative variant for IIN and can further enrich the mutation spectrum and uncover the etiology of IIN.
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Affiliation(s)
- Fengqi Wang
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hongzai Guan
- Department of Clinical Hematology, Medical College of Qingdao University, Qingdao, China
| | - Wenmiao Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Guiqiu Zhao
- Department of Ophthalmology, The Affiliated Hospital of Qingdao University, Qingdao, China
| | - Shiguo Liu
- Medical Genetic Department, The Affiliated Hospital of Qingdao University, Qingdao, China.,Prenatal Diagnosis Center, The Affiliated Hospital of Qingdao University, Qingdao, China
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18
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Thomas MG, Maconachie GDE, Constantinescu CS, Chan WM, Barry B, Hisaund M, Sheth V, Kuht HJ, Dineen RA, Harieaswar S, Engle EC, Gottlob I. Congenital monocular elevation deficiency associated with a novel TUBB3 gene variant. Br J Ophthalmol 2019; 104:547-550. [PMID: 31302631 PMCID: PMC6998158 DOI: 10.1136/bjophthalmol-2019-314293] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 06/15/2019] [Accepted: 06/23/2019] [Indexed: 11/24/2022]
Abstract
Background The genetic basis of monocular elevation deficiency (MED) is unclear. It has previously been considered to arise due to a supranuclear abnormality. Methods Two brothers with MED were referred to Leicester Royal Infirmary, UK from the local opticians. Their father had bilateral ptosis and was unable to elevate both eyes, consistent with the diagnosis of congenital fibrosis of extraocular muscles (CFEOM). Candidate sequencing was performed in all family members. Results Both affected siblings (aged 7 and 12 years) were unable to elevate the right eye. Their father had bilateral ptosis, left esotropia and bilateral limitation of elevation. Chin up head posture was present in the older sibling and the father. Bell’s phenomenon and vertical rotational vestibulo-ocular reflex were absent in the right eye for both children. Mild bilateral facial nerve palsy was present in the older sibling and the father. Both siblings had slight difficulty with tandem gait. MRI revealed hypoplastic oculomotor nerve. Left anterior insular focal cortical dysplasia was seen in the older sibling. Sequencing of TUBB3 revealed a novel heterozygous variant (c.1263G>C, p.E421D) segregating with the phenotype. This residue is in the C-terminal H12 α-helix of β-tubulin and is one of three putative kinesin binding sites. Conclusion We show that familial MED can arise from a TUBB3 variant and could be considered a limited form of CFEOM. Neurological features such as mild facial palsy and cortical malformations can be present in patients with MED. Thus, in individuals with congenital MED, consideration may be made for TUBB3 mutation screening.
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Affiliation(s)
- Mervyn G Thomas
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Gail D E Maconachie
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | | | - Wai-Man Chan
- Howard Hughes Medical Institute, Chevy Chase, Mayland, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Brenda Barry
- Howard Hughes Medical Institute, Chevy Chase, Mayland, United States.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, United States
| | - Michael Hisaund
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Viral Sheth
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Helen J Kuht
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Rob A Dineen
- Department of Radiology, University of Nottingham, Nottingham, UK
| | - Sreemathi Harieaswar
- Department of Radiology, University Hospitals of Leicester NHS Trust, Leicester, UK
| | - Elizabeth C Engle
- Howard Hughes Medical Institute, Chevy Chase, Mayland, United States.,Departments of Neurology and Ophthalmology, Boston Children's Hospital, Boston, Massachusetts, United States.,Departments of Neurology and Ophthalmology, Harvard Medical Schoool, Boston, Massachusetts, United States
| | - Irene Gottlob
- Ulverscroft Eye Unit, Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
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19
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Yan N, Xiao L, Hou C, Guo B, Fan W, Deng Y, Ma K. X-linked inheritances recessive of congenital nystagmus and autosomal dominant inheritances of congenital cataracts coexist in a Chinese family: a case report and literature review. BMC MEDICAL GENETICS 2019; 20:41. [PMID: 30890130 PMCID: PMC6423883 DOI: 10.1186/s12881-019-0780-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 03/07/2019] [Indexed: 02/05/2023]
Abstract
BACKGROUND Congenital nystagmus (CN) and congenital cataracts are distinct eye diseases and are usually isolated. Cases with CN and congenital cataracts caused by different genes in one family have been rarely reported. CASE PRESENTATION A 27-year-old man presented with CN and congenital cataracts and he underwent cataract extraction 2 weeks after birth. Three years later, he had posterior chamber intraocular lens implantation. The proband's mother was only afflicted by bilateral lens opacities. Lensectomy was performed in both eyes at age 15. The proband's daughter had bilateral central cataracts and no nystagmus. She had undergone cataract extraction when she was two months old. In this family, 8 affected individuals were affected by bilateral cataracts, and three of them presented with CN. The genetic analysis was performed using a specific Hereditary Ophthalmological Disease Gene Panel on proband and his parents (one of which was a patient). PCR and Sanger sequencing verified the presence of these variants in all members of the family. The novel mutation, c.498-3C > T, in FRMD7 explains why X-Linked recessive inheritance of CN was found in a subset of patients. A heterozygous mutation of the GJA8 gene (c.139G > C), was identified in all patients and thus explains the autosomal dominant pattern of inheritance of congenital cataracts within the family. CONCLUSIONS This is the first time that FRMD7 and GJA8 gene mutations have been linked to the pathogenesis of a family with both CN and congenital cataracts. The phenomenon of two different genetic patterns coexisting in one family is rare.
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Affiliation(s)
- Naihong Yan
- Research Laboratory of Ophthalmology and Vision Sciences, Torsten-Wiesel Research Institute of World Eye Organization, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Lirong Xiao
- Research Laboratory of Ophthalmology and Vision Sciences, Torsten-Wiesel Research Institute of World Eye Organization, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Chen Hou
- Research Laboratory of Ophthalmology and Vision Sciences, Torsten-Wiesel Research Institute of World Eye Organization, West China Hospital, Sichuan University, Chengdu, 610041, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Bo Guo
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Wei Fan
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Yingping Deng
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China
| | - Ke Ma
- Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, 610041, China.
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20
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Choi JH, Jung JH, Oh EH, Shin JH, Kim HS, Seo JH, Choi SY, Kim MJ, Choi HY, Lee C, Choi KD. Genotype and Phenotype Spectrum of FRMD7-Associated Infantile Nystagmus Syndrome. Invest Ophthalmol Vis Sci 2019; 59:3181-3188. [PMID: 30025138 DOI: 10.1167/iovs.18-24207] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose We investigate the genotype and phenotype spectrum of FRMD7-associated infantile nystagmus syndrome in Korean probands. Methods A total of 37 patients with infantile nystagmus syndrome were recruited prospectively for genetic analysis. We performed polymerase chain reaction (PCR)-based direct sequencing and haplotype analysis for FRMD7. Detailed ophthalmic examinations and eye movement recordings were compared between FRMD7 and non-FRMD7 groups. Results In 13 (35%) of 37 patients, five different mutations of FRMD7 were detected: start codon mutation c.1A>G, splice site mutation c.162+6T>C, and three missense mutations (c.575A>C, c.722A>G, and c.875T>C). The latter mutation was identified in seven unrelated patients, and always was accompanied with two single nucleotide polymorphisms of exon 12 (rs6637934, rs5977623). Compared to non-FRMD7 groups, a cup-to-disc ratio was significantly decreased in FRMD7 groups (P < 0.001), and a disc-macula distance to disc diameter ratio markedly increased in the FRMD7 group (P = 0.015). Most patients in the FRMD7 group had at least two types of the nystagmus waveforms, and the most common type was unidirectional jerk nystagmus (75%), such as pure jerk and jerk with extended foveation, followed by pendular (25%), bidirectional jerk (19%), and dual jerk (6%) nystagmus. No significant differences were observed between FRMD7 and non-FRMD7 groups in terms of the nystagmus waveform, presence of periodic alternating nystagmus, and mean foveation time. Conclusions We identified five FRMD7 mutations in 35% of our infantile nystagmus syndrome cohort, expanding its mutational spectrum. The missense mutation c.875T>C may be a common mutation arisen from the founder effect in Korea. Optic nerve dysplasia associated with FRMD7 mutations suggests that the abnormal development of afferent visual systems may affect neural circuitry within the oculomotor system.
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Affiliation(s)
- Jae-Hwan Choi
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Jae-Ho Jung
- Department of Ophthalmology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Eun Hye Oh
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Hyang-Sook Kim
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Je Hyun Seo
- Department of Ophthalmology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, South Korea
| | - Seo Young Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea
| | - Min-Ji Kim
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea
| | - Hee Young Choi
- Department of Ophthalmology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea
| | - Changwook Lee
- Department of Biological Sciences, School of Life Sciences, Ulsan National Institute of Sciences and Technology, Ulsan, South Korea
| | - Kwang-Dong Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, South Korea
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21
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Wu S, Deng S, Song Z, Xu H, Yang Z, Liu X, Qi L, Deng H, Yuan L. A Disease-Causing FRMD7 Variant in a Chinese Family with Infantile Nystagmus. J Mol Neurosci 2019; 67:418-423. [PMID: 30618027 DOI: 10.1007/s12031-018-1245-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 12/14/2018] [Indexed: 11/29/2022]
Abstract
In this report, we described a large Han-Chinese family which presents with various phenotypes from unaffected to manifested nystagmus in females. Infantile nystagmus (IN) is characterized by bilateral, involuntary, and periodic eyeball oscillation, occurring at birth or within the first 6 months. The most common inheritance pattern of IN is an X-linked form with incomplete penetrance among females, and the FERM domain containing 7 gene (FRMD7) is a main disease-causing gene. A combination of exome sequencing and Sanger sequencing, as well as detailed clinical examinations were performed on the Chinese IN family. An FRMD7 c.47T>C (p.Phe16Ser) variant was proposed as the disease-causing variant. Incomplete penetrance was found in females with the FRMD7 c.47T>C variant, and hemizygous male affected subjects presented more severe manifestations compared to heterozygous female affected subjects. These findings could enhance genetic counseling and antenatal diagnosis of IN.
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Affiliation(s)
- Shan Wu
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, 410013, Hunan, People's Republic of China
| | - Sheng Deng
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, China
| | - Zhi Song
- Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongbo Xu
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, 410013, Hunan, People's Republic of China
| | - Zhijian Yang
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, 410013, Hunan, People's Republic of China
| | - Xin Liu
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, 410013, Hunan, People's Republic of China
| | - Li Qi
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, 410013, Hunan, People's Republic of China
| | - Hao Deng
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, 410013, Hunan, People's Republic of China.,Department of Neurology, the Third Xiangya Hospital, Central South University, Changsha, China
| | - Lamei Yuan
- Center for Experimental Medicine, the Third Xiangya Hospital, Central South University, 138 Tongzipo Road, Changsha, 410013, Hunan, People's Republic of China.
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22
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Kaski D, Haider S, Male A, Radunovich A, Liu F, Cordivari C, Bhatia KP, Bronstein AM. Adult Periodic Alternating Nystagmus Masked by Involuntary Head Movements. Front Neurol 2018; 9:326. [PMID: 29867735 PMCID: PMC5960698 DOI: 10.3389/fneur.2018.00326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 04/24/2018] [Indexed: 11/13/2022] Open
Abstract
Acquired periodic alternating nystagmus (PAN) describes a horizontal jerk nystagmus that reverses its direction with a predictable cycle, and is thought to arise from lesions involving the brainstem and cerebellum. We report a 20-year-old patient with PAN who presented with an acute vertiginous episode and developed an involuntary head movement that initially masked the PAN. The involuntary head movements were abolished with a subtherapeutic dose of botulinum toxin to the neck muscles. We propose that the head movements initially developed as a compensatory movement to the nystagmus, to maintain visual fixation in the presence of the underlying nystagmus, and became an entrained involuntary behavior. This case highlights the importance of disambiguating psychogenic from organic pathology as this may have clinical therapeutic implications, in this case resolution of the most disabling symptom which was her head oscillations, leading to improved day-to-day function despite PAN.
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Affiliation(s)
- Diego Kaski
- Department of Neuro-Otology, University College London Hospitals, London, United Kingdom.,Department of Brain Sciences, Imperial College London, London, United Kingdom
| | - Salman Haider
- Department of Neurology, Royal London Hospital, London, United Kingdom
| | - Amanda Male
- Department of Neuro-Otology, University College London Hospitals, London, United Kingdom
| | - Alex Radunovich
- Department of Neurology, Royal London Hospital, London, United Kingdom
| | - Fan Liu
- Department of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Carla Cordivari
- Department of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Kailash P Bhatia
- Department of Neurology, National Hospital for Neurology and Neurosurgery, London, United Kingdom
| | - Adolfo M Bronstein
- Department of Neuro-Otology, University College London Hospitals, London, United Kingdom.,Department of Brain Sciences, Imperial College London, London, United Kingdom
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23
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Tarnutzer AA, Straumann D, Salman MS. Neuro-ophthalmologic assessment and investigations in children and adults with cerebellar diseases. THE CEREBELLUM: FROM EMBRYOLOGY TO DIAGNOSTIC INVESTIGATIONS 2018; 154:305-327. [DOI: 10.1016/b978-0-444-63956-1.00019-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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24
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Han J, Lee T, Lee JB, Han SH. Retinal microstructures are altered in patients with idiopathic infantile nystagmus. Graefes Arch Clin Exp Ophthalmol 2017; 255:1661-1668. [PMID: 28616716 DOI: 10.1007/s00417-017-3713-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 03/26/2017] [Accepted: 05/30/2017] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To compare segmented retinal layer thicknesses between patients with idiopathic infantile nystagmus (IIN) and controls. METHODS This retrospective case-control study included 66 patients with IIN and 66 age-matched controls. The retinal layers were examined using spectral domain optical coherence tomography with autosegmentation. Central foveal thickness (CFT), outer nuclear layer (ONL), and outer segment length (OSL) thickness were measured at the fovea center. Mean values for retinal nerve fiber layer, ganglion cell inner plexiform layer (GCIPL), inner nuclear layer, outer plexiform-outer nuclear layer (OPNL) thicknesses were calculated at two measurement points (nasal and temporal hump points at the macula area). RESULTS There were no significant between-group differences in age, gender, or refraction error. The CFT was thicker in the IIN group compared with the control group (225.0 μm vs. 217.8 μm, P = 0.017) and OSL was shorter in IIN than in controls (40.0 μm vs. 43.7 μm., P < 0.001). The ONL thickness at the central fovea was not statistically different between the two groups. At the nasal and temporal position where the ganglion cell density was thickest, the GCIPL thickness was thinner in the IIN group compared to the controls (99.5 μm vs. 102.8 μm, P = 0.010). The GCIPL thickness was negatively correlated with logMAR visual acuity (Spearman's rho = -0.502, P < 0.001). CONCLUSIONS The foveal pit was shallower, OSL was shorter, and the GCIPL thicknesses at macular humps were decreased in the patients with IIN compared with that of controls. The faulty development of the macula may be related to unknown pathophysiologic mechanism during fovea maturation in IIN or continuous eye movement itself interrupt fovea development.
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Affiliation(s)
- Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, Korea
- Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul, Seodaemun-gu, 03572, Korea
| | - Taekjune Lee
- Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul, Seodaemun-gu, 03572, Korea
| | - Jong Bok Lee
- Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul, Seodaemun-gu, 03572, Korea
- Kong Eye Center, Seoul, Korea
| | - Sueng-Han Han
- Institute of Vision Research, Department of Ophthalmology, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seoul, Seodaemun-gu, 03572, Korea.
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25
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Verma R, Ramkumar HL, Zhang K, Granet DB, Hertle RW. X-Linked Idiopathic Infantile Nystagmus (XLIIN): Case Report and Review of Literature. CURRENT OPHTHALMOLOGY REPORTS 2017. [DOI: 10.1007/s40135-017-0139-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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26
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Yonehara K, Fiscella M, Drinnenberg A, Esposti F, Trenholm S, Krol J, Franke F, Scherf BG, Kusnyerik A, Müller J, Szabo A, Jüttner J, Cordoba F, Reddy AP, Németh J, Nagy ZZ, Munier F, Hierlemann A, Roska B. Congenital Nystagmus Gene FRMD7 Is Necessary for Establishing a Neuronal Circuit Asymmetry for Direction Selectivity. Neuron 2015; 89:177-93. [PMID: 26711119 PMCID: PMC4712192 DOI: 10.1016/j.neuron.2015.11.032] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Revised: 08/14/2015] [Accepted: 11/18/2015] [Indexed: 12/24/2022]
Abstract
Neuronal circuit asymmetries are important components of brain circuits, but the molecular pathways leading to their establishment remain unknown. Here we found that the mutation of FRMD7, a gene that is defective in human congenital nystagmus, leads to the selective loss of the horizontal optokinetic reflex in mice, as it does in humans. This is accompanied by the selective loss of horizontal direction selectivity in retinal ganglion cells and the transition from asymmetric to symmetric inhibitory input to horizontal direction-selective ganglion cells. In wild-type retinas, we found FRMD7 specifically expressed in starburst amacrine cells, the interneuron type that provides asymmetric inhibition to direction-selective retinal ganglion cells. This work identifies FRMD7 as a key regulator in establishing a neuronal circuit asymmetry, and it suggests the involvement of a specific inhibitory neuron type in the pathophysiology of a neurological disease. Video Abstract
FRMD7 is required for the horizontal optokinetic reflex in mice as in humans Horizontal direction selectivity is lost in the retina of FRMD7 mutant mice Asymmetry of inhibitory inputs to horizontal DS cells is lost in FRMD7 mutant mice FRMD7 is expressed in ChAT-expressing cells in the retina of mice and primates
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Affiliation(s)
- Keisuke Yonehara
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Michele Fiscella
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Antonia Drinnenberg
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Federico Esposti
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Stuart Trenholm
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Jacek Krol
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Felix Franke
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Brigitte Gross Scherf
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Akos Kusnyerik
- Department of Ophthalmology, Semmelweis University, Mária u. 39, 1085 Budapest, Hungary
| | - Jan Müller
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Arnold Szabo
- Department of Human Morphology and Developmental Biology, Faculty of Medicine, Semmelweis University, Tűzoltó u. 58, 1094 Budapest, Hungary
| | - Josephine Jüttner
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Francisco Cordoba
- Laboratory and Animal Services, Novartis Institute for Biomedical Research, Fabrikstrasse 28, 4056 Basel, Switzerland
| | - Ashrithpal Police Reddy
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - János Németh
- Department of Ophthalmology, Semmelweis University, Mária u. 39, 1085 Budapest, Hungary
| | - Zoltán Zsolt Nagy
- Department of Ophthalmology, Semmelweis University, Mária u. 39, 1085 Budapest, Hungary
| | - Francis Munier
- Jules-Gonin Eye Hospital, Avenue de France 15, 1000 Lausanne, Switzerland
| | - Andreas Hierlemann
- Bio Engineering Laboratory, Department of Biosystems Science and Engineering of ETH Zurich, Mattenstrasse 26, 4058 Basel, Switzerland
| | - Botond Roska
- Neural Circuit Laboratories, Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; Department of Ophthalmology, University of Basel, Mittlere Strasse 91, 4031 Basel, Switzerland.
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27
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Penix K, Swanson MW, DeCarlo DK. Nystagmus in pediatric patients: interventions and patient-focused perspectives. Clin Ophthalmol 2015; 9:1527-36. [PMID: 26345377 PMCID: PMC4551307 DOI: 10.2147/opth.s62786] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Nystagmus refers to involuntary, typically conjugate, often rhythmic oscillations of the eyes. The most common cause of nystagmus in children is infantile nystagmus syndrome (INS). INS presents within the first few months of life and is sometimes accompanied by an ocular condition associated with sensory impairment. Because this condition affects a person throughout life, it is important to understand the options available to manage it. This review focuses on the underlying nystagmus etiology, psychosocial and functional effects of nystagmus, as well as current principles of management, including optical, pharmacological, surgical, and rehabilitative options. Currently, the neural mechanisms underlying INS are not fully understood. Treatment options are designed to increase foveation duration or correct anomalous head postures; however, evidence is limited to mainly pre- and post-study designs with few objective comparisons of treatment strategies. Management of INS should be individualized. The decision on which treatment is best suited for a particular patient lies with the patient and his/her physician.
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Affiliation(s)
- Kimberly Penix
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Mark W Swanson
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Dawn K DeCarlo
- School of Optometry, University of Alabama at Birmingham, Birmingham, AL, USA
- Department of Ophthalmology, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA
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28
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Choi JH, Shin JH, Seo JH, Jung JH, Choi KD. A start codon mutation of the FRMD7 gene in two Korean families with idiopathic infantile nystagmus. Sci Rep 2015; 5:13003. [PMID: 26268155 PMCID: PMC4534761 DOI: 10.1038/srep13003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/10/2015] [Indexed: 11/09/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is the involuntary oscillation of the eyes with onset in the first few months of life. The most common form of inheritance is X-linked, and mutations in FRMD7 gene are a major cause. To identify the FRMD7 gene mutations associated with X-linked IIN, we performed PCR-based DNA direct sequencing in 4 affected subjects from 2 Korean families. We also assessed structural abnormalities of retina and optic nerve head using optical coherence tomography (OCT). Genetic analysis revealed a A>G transversion at nucleotide c.1, the first base of the start codon. This mutation leads to the loss of the primary start codon ATG for methionine, which is replaced by a triplet GTG for valine. The alternative in-frame start codon is not present around a mutation. OCT revealed the morphological changes within the optic nerve head, including shallow cup depth and small cup-to-disc ratio. In summary, we identified a novel start codon mutation within the FRMD7 gene of 2 Korean families. Our data expands the mutation spectrum of FRMD7 causing IIN. We also demonstrated abnormal developments of afferent system in patients with FRMD7 mutations using OCT, which may help to understand the etiological factor in development of nystagmus.
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Affiliation(s)
- Jae-Hwan Choi
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Je Hyun Seo
- Department of Ophthalmology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jae-Ho Jung
- Department of Ophthalmology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Kwang-Dong Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, Korea
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Abstract
PURPOSE OF REVIEW Mechanisms underlying infantile nystagmus are unclear. The aim of this review is to outline recent developments in understanding the aetiology of infantile nystagmus. RECENT FINDINGS There have been advances in understanding mechanisms underlying idiopathic infantile nystagmus, which has progressed through determining the role of the FRMD7 gene in controlling neurite outgrowth, and albinism, in which recent models have investigated the possibility of retinal miswiring leading to nystagmus. We also briefly review aetiology of infantile nystagmus in afferent visual deficits caused by ocular disease, and PAX6 mutations. Improved phenotypical characterization of all these infantile nystagmus subtypes has been achieved recently through high-resolution retinal imaging using optical coherence tomography. Several new hypotheses proposing common mechanisms that could underlie various infantile nystagmus subtypes are also highlighted. SUMMARY Although there is still no consensus of opinion regarding the mechanisms causing infantile nystagmus, identification of new genes and determining their cellular function, phenotypical characterization of genetic subtypes, and improvements in animal models have significantly advanced our understanding of infantile nystagmus. These recent developments pave the way to achieving a much clearer picture of infantile nystagmus aetiology in the future.
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Chhetri J, Jacobson G, Gueven N. Zebrafish--on the move towards ophthalmological research. Eye (Lond) 2014; 28:367-80. [PMID: 24503724 PMCID: PMC3983641 DOI: 10.1038/eye.2014.19] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/15/2014] [Indexed: 12/15/2022] Open
Abstract
Millions of people are affected by visual impairment and blindness globally, and the prevalence of vision loss is likely to increase as we are living longer. However, many ocular diseases remain poorly controlled due to lack of proper understanding of the pathogenesis and the corresponding lack of effective therapies. Consequently, there is a major need for animal models that closely mirror the human eye pathology and at the same time allow higher-throughput drug screening approaches. In this context, zebrafish as an animal model organism not only address these needs but can in many respects reflect the human situation better than the current rodent models. Over the past decade, zebrafish have become an established model to study a variety of human diseases and are more recently becoming a valuable tool for the study of human ophthalmological disorders. Many human ocular diseases such as cataract, glaucoma, diabetic retinopathy, and age-related macular degeneration have already been modelled in zebrafish. In addition, zebrafish have become an attractive model for pre-clinical drug toxicity testing and are now increasingly used by scientists worldwide for the discovery of novel treatment approaches. This review presents the advantages and uses of zebrafish for ophthalmological research.
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Affiliation(s)
- J Chhetri
- School of Pharmacy, University of Tasmania, Hobart, TAS, Australia
| | - G Jacobson
- School of Pharmacy, University of Tasmania, Hobart, TAS, Australia
| | - N Gueven
- School of Pharmacy, University of Tasmania, Hobart, TAS, Australia
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31
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Thomas MG, Crosier M, Lindsay S, Kumar A, Araki M, Leroy BP, McLean RJ, Sheth V, Maconachie G, Thomas S, Moore AT, Gottlob I. Abnormal retinal development associated with FRMD7 mutations. Hum Mol Genet 2014; 23:4086-93. [PMID: 24688117 PMCID: PMC4082370 DOI: 10.1093/hmg/ddu122] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is a genetically heterogeneous disorder, often associated with FRMD7 mutations. As the appearance of the retina is reported to be normal based on conventional fundus photography, IIN is postulated to arise from abnormal cortical development. To determine whether the afferent visual system is involved in FRMD7 mutations, we performed in situ hybridization studies in human embryonic and fetal stages (35 days post-ovulation to 9 weeks post-conception). We show a dynamic retinal expression pattern of FRMD7 during development. We observe expression within the outer neuroblastic layer, then in the inner neuroblastic layer and at 9 weeks post-conception a bilaminar expression pattern. Expression was also noted within the developing optic stalk and optic disk. We identified a large cohort of IIN patients (n = 100), and performed sequence analysis which revealed 45 patients with FRMD7 mutations. Patients with FRMD7 mutations underwent detailed retinal imaging studies using ultrahigh-resolution optical coherence tomography. The tomograms were compared with a control cohort (n = 60). The foveal pit was significantly shallower in FRMD7 patients (P < 0.0001). The optic nerve head morphology was abnormal with significantly decreased optic disk area, retinal nerve fiber layer thickness, cup area and cup depth in FRMD7 patients (P < 0.0001). This study shows for the first time that abnormal afferent system development is associated with FRMD7 mutations and could be an important etiological factor in the development of nystagmus.
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Affiliation(s)
- Mervyn G Thomas
- Ophthalmology Group, School of Medicine, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Moira Crosier
- MRC-Wellcome Trust Human Developmental Biology Resource (Newcastle), Institute of Human Genetics, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - Susan Lindsay
- MRC-Wellcome Trust Human Developmental Biology Resource (Newcastle), Institute of Human Genetics, Newcastle University, International Centre for Life, Newcastle upon Tyne NE1 3BZ, UK
| | - Anil Kumar
- Ophthalmology Group, School of Medicine, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Masasuke Araki
- Department of Biological Sciences, Developmental Neurobiology Laboratory, Nara Women's University, Nara 630-8506, Japan
| | - Bart P Leroy
- Department of Ophthalmology and Centre for Medical Genetics, Ghent University and Ghent University Hospital, Ghent 9000, Belgium
| | - Rebecca J McLean
- Ophthalmology Group, School of Medicine, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Viral Sheth
- Ophthalmology Group, School of Medicine, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Gail Maconachie
- Ophthalmology Group, School of Medicine, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
| | - Shery Thomas
- Ophthalmology Group, School of Medicine, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK Department of Ophthalmology, Nottingham University Hospital NHS Trust, Nottingham, UK
| | | | - Irene Gottlob
- Ophthalmology Group, School of Medicine, University of Leicester, RKCSB, PO Box 65, Leicester LE2 7LX, UK
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Guo Y, Song Z, Xu H, Yi J, Zheng W, Xiang H, Deng X, Lv H, Gao K, Qi Y, Deng H. Heterogeneous phenotype in a family with the FERM domain-containing 7 gene R335X mutation. Can J Ophthalmol 2014; 49:50-3. [PMID: 24513357 DOI: 10.1016/j.jcjo.2013.09.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 08/23/2013] [Accepted: 09/13/2013] [Indexed: 10/25/2022]
Abstract
OBJECTIVE Infantile nystagmus (IN) is characterized by bilateral involuntary, periodic, and predominantly ocular oscillations. In this article, we describe a mutation screen conducted on a 4-generation family in which 4 patients were affected with X-linked IN (XLIN). DESIGN Experimental study. PARTICIPANTS A 4-generation Chinese Han family including 4 symptomatic members with IN and 200 normal male controls. METHODS DNA was extracted from peripheral blood, and the FERM domain-containing 7 gene (FRMD7) was amplified on DNA samples of all the available family members. The mutation screen was conducted by performing direct DNA sequencing. RESULTS A nonsense mutation (R335X) in the FRMD7 gene was identified in 4 male patients and an asymptomatic female member. CONCLUSIONS Although the R335X mutation in the FRMD7 gene has been previously described, the clinical features, including both disease penetrance and severity, among individuals with FRMD7 mutation in our family vary greatly. One female member with the heterozygous R335X mutation had no clinical manifestation of the disease. This incomplete penetrance suggests that random X-chromosome inactivation may play a role in the pathogenesis of IN, and that loss of functional FRMD7 may account for the development of this disorder. Our findings may be helpful in the genetic counseling of patients with nystagmus.
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Affiliation(s)
- Yi Guo
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China; Department of Medical Information, Xiangya School of Medicine, Central South University, Changsha, China; Department of Neurology, Third Xiangya Hospital, Central South University, Changsha, China
| | - Zhi Song
- Department of Neurology, Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongbo Xu
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China
| | - Junhui Yi
- Department of Ophthalmology, Third Xiangya Hospital, Central South University, Changsha, China
| | - Wen Zheng
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China; Department of Neurology, Third Xiangya Hospital, Central South University, Changsha, China
| | - Hong Xiang
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China
| | - Xiong Deng
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China
| | - Hongwei Lv
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China
| | - Kai Gao
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China
| | - Yong Qi
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China
| | - Hao Deng
- Center for Experimental Medicine, Third Xiangya Hospital, Central South University, Changsha, China; Department of Neurology, Third Xiangya Hospital, Central South University, Changsha, China.
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33
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Song FW, Chen BB, Sun ZH, Wu LP, Zhao SJ, Miao Q, Tang XJ. Novel mutation c.980_983delATTA compound with c.986C>A mutation of the FRMD7 gene in a Chinese family with X-linked idiopathic congenital nystagmus. J Zhejiang Univ Sci B 2014; 14:479-86. [PMID: 23733424 DOI: 10.1631/jzus.b1200259] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To screen mutations in FERM domain-containing protein 7 (FRMD7) gene in two Chinese families with X-linked idiopathic congenital nystagmus (XLICN). METHODS Common ophthalmic data and peripheral blood of two Chinese XLICN families (families A and B) were collected after informed consent. Genomic DNA was prepared from the peripheral blood of members of the two families and from 100 normal controls. Mutations in the FRMD7 gene were determined by directly sequencing polymerase chain reaction (PCR) products. RESULTS We identified a novel mutation c.980_983delATTA compound with c.986C>A mutation in the 11th exon of FRMD7 in family B, and a previously reported splicing mutation c.781C>G (p.R261G) [corrected] in family A. The mutations were detected in patients and female carriers, while they were absent in other relatives or in the 100 normal controls. CONCLUSIONS Our results expand the spectrum of FRMD7 mutations in association with XLICN, and further confirm that the mutations of FRMD7 are the underlying molecular mechanism for XLICN.
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Affiliation(s)
- Feng-wei Song
- Eye Center, the Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310009, China
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Thomas S, Thomas MG, Andrews C, Chan WM, Proudlock FA, McLean RJ, Pradeep A, Engle EC, Gottlob I. Autosomal-dominant nystagmus, foveal hypoplasia and presenile cataract associated with a novel PAX6 mutation. Eur J Hum Genet 2013; 22:344-9. [PMID: 23942204 DOI: 10.1038/ejhg.2013.162] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 05/12/2013] [Accepted: 05/15/2013] [Indexed: 11/09/2022] Open
Abstract
Autosomal-dominant idiopathic infantile nystagmus has been linked to 6p12 (OMIM 164100), 7p11.2 (OMIM 608345) and 13q31-q33 (OMIM 193003). PAX6 (11p13, OMIM 607108) mutations can also cause autosomal-dominant nystagmus, typically in association with aniridia or iris hypoplasia. We studied a large multigenerational white British family with autosomal-dominant nystagmus, normal irides and presenile cataracts. An SNP-based genome-wide analysis revealed a linkage to a 13.4-MB region on chromosome 11p13 with a maximum lod score of 2.93. A mutation analysis of the entire coding region and splice junctions of the PAX6 gene revealed a novel heterozygous missense mutation (c.227C>G) that segregated with the phenotype and is predicted to result in the amino-acid substitution of proline by arginine at codon 76 p.(P76R). The amino-acid variation p.(P76R) within the paired box domain is likely to destabilise the protein due to steric hindrance as a result of the introduction of a polar and larger amino acid. Eye movement recordings showed a significant intrafamilial variability of horizontal, vertical and torsional nystagmus. High-resolution in vivo imaging of the retina using optical coherence tomography (OCT) revealed features of foveal hypoplasia, including rudimentary foveal pit, incursion of inner retinal layers, short photoreceptor outer segments and optic nerve hypoplasia. Thus, this study presents a family that segregates a PAX6 mutation with nystagmus and foveal hypoplasia in the absence of iris abnormalities. Moreover, it is the first study showing detailed characteristics using eye movement recordings of autosomal-dominant nystagmus in a multigenerational family with a novel PAX6 mutation.
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Affiliation(s)
- Shery Thomas
- 1] Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK [2] Department of Ophthalmology, Nottingham University Hospital NHS Trust, Nottingham, UK
| | - Mervyn G Thomas
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Caroline Andrews
- 1] Department of Neurology, Ophthalmology, Medicine (Genetics), FM Kirby Neurobiology Center, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA [2] Department of Neurology, Harvard Medical School, Boston, MA, USA [3] Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Wai-Man Chan
- 1] Department of Neurology, Ophthalmology, Medicine (Genetics), FM Kirby Neurobiology Center, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA [2] Department of Neurology, Harvard Medical School, Boston, MA, USA [3] Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Frank A Proudlock
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Rebecca J McLean
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Archana Pradeep
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Elizabeth C Engle
- 1] Department of Neurology, Ophthalmology, Medicine (Genetics), FM Kirby Neurobiology Center, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA [2] Department of Neurology, Harvard Medical School, Boston, MA, USA [3] Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Irene Gottlob
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
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Watkins RJ, Patil R, Goult BT, Thomas MG, Gottlob I, Shackleton S. A novel interaction between FRMD7 and CASK: evidence for a causal role in idiopathic infantile nystagmus. Hum Mol Genet 2013; 22:2105-18. [PMID: 23406872 PMCID: PMC3633374 DOI: 10.1093/hmg/ddt060] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is a genetically heterogeneous disorder of eye movement that can be caused by mutations in the FRMD7 gene that encodes a FERM domain protein. FRMD7 is expressed in the brain and knock-down studies suggest it plays a role in neurite extension through modulation of the actin cytoskeleton, yet little is known about its precise molecular function and the effects of IIN mutations. Here, we studied four IIN-associated missense mutants and found them to have diverse effects on FRMD7 expression and cytoplasmic localization. The C271Y mutant accumulates in the nucleus, possibly due to disruption of a nuclear export sequence located downstream of the FERM-adjacent domain. While overexpression of wild-type FRMD7 promotes neurite outgrowth, mutants reduce this effect to differing degrees and the nuclear localizing C271Y mutant acts in a dominant-negative manner to inhibit neurite formation. To gain insight into FRMD7 molecular function, we used an IP-MS approach and identified the multi-domain plasma membrane scaffolding protein, CASK, as a FRMD7 interactor. Importantly, CASK promotes FRMD7 co-localization at the plasma membrane, where it enhances CASK-induced neurite length, whereas IIN-associated FRMD7 mutations impair all of these features. Mutations in CASK cause X-linked mental retardation. Patients with C-terminal CASK mutations also present with nystagmus and, strikingly, we show that these mutations specifically disrupt interaction with FRMD7. Together, our data strongly support a model whereby CASK recruits FRMD7 to the plasma membrane to promote neurite outgrowth during development of the oculomotor neural network and that defects in this interaction result in nystagmus.
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Affiliation(s)
- Rachel J Watkins
- Department of Biochemistry, University of Leicester, Leicester, UK
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36
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Thomas MG, Gottlob I. Optical Coherence Tomography Studies Provides New Insights into Diagnosis and Prognosis of Infantile Nystagmus: A Review. Strabismus 2012; 20:175-80. [DOI: 10.3109/09273972.2012.735336] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Mervyn G. Thomas
- Ophthalmology Group, School of Medicine, University of Leicester,
Leicester, UK
| | - Irene Gottlob
- Ophthalmology Group, School of Medicine, University of Leicester,
Leicester, UK
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37
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Xiao X, Li S, Guo X, Zhang Q. A novel locus for autosomal dominant congenital motor nystagmus mapped to 1q31-q32.2 between D1S2816 and D1S2692. Hum Genet 2011; 131:697-702. [PMID: 22065086 DOI: 10.1007/s00439-011-1113-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Accepted: 10/29/2011] [Indexed: 10/15/2022]
Abstract
Congenital motor nystagmus (CMN) is characterized by bilateral involuntary ocular oscillation without any other underlying ocular or systemic diseases. An autosomal dominant CMN was identified in a large Chinese family where all patients had nystagmus since infancy. The nystagmus in the family is independent of any known ocular or systemic diseases. After exclusion of known CMN loci, a genome-wide scan was performed by genotyping microsatellite markers at about 10 cM intervals, together with two-point linkage analysis. Exome sequencing was used to screen coding exons of well-annotated genes. Sanger-dideoxy sequencing was used to verify candidate variations inside the linkage interval. Congenital motor nystagmus in this family shows linkage to markers in a 11.39 Mb (12.1 cM) region on chromosome 1q31-q32.2 between D1S2816 and D1S2692. All nine markers in the linkage interval gave positive lod scores, with D1S2655 and D1S2636 yielding lod scores of 5.16 and 5.18, respectively, at θ = 0. No causative mutation in the linkage interval was identified by exome sequencing of gDNA from four patients. A linkage study of additional families and further analysis of candidate genes may ultimately lead to identification of the gene responsible for dominantly inherited CMN.
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Affiliation(s)
- Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060 Guangzhou, China.
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The Role of FRMD7 in Idiopathic Infantile Nystagmus. J Ophthalmol 2011; 2012:460956. [PMID: 21904664 PMCID: PMC3163398 DOI: 10.1155/2012/460956] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 06/20/2011] [Indexed: 11/21/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is an inherited disorder in which the nystagmus arises independently of any other symptoms, leading to the speculation that the disorder represents a primary defect in the area of the brain responsible for ocular motor control. The inheritance patterns are heterogeneous, however the most common form is X-linked. FRMD7 resides at Xq26-27 and approximately 50% of X-linked IIN families map to this region. Currently 45 mutations within FRMD7 have been associated with IIN, confirming the importance of FRMD7 in the pathogenesis of the disease. Although mutations in FRMD7 are known to cause IIN, very little is known about the function of the protein. FRMD7 contains a conserved N-terminal FERM domain suggesting that it may provide a link between the plasma membrane and actin cytoskeleton. Limited studies together with the knowledge of the function of other FERM domain containing proteins, suggest that FRMD7 may play a role in membrane extension during neuronal development through remodeling of the actin cytoskeleton.
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