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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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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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3
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Schlottmann PG, Luna JD, Labat N, Yadarola MB, Bainttein S, Esposito E, Ibañez A, Barbaro EI, Álvarez Mendiara A, Picotti CP, Chirino Misisian A, Andreussi L, Gras J, Capalbo L, Visotto M, Dipierri JE, Alcoba E, Fernández Gabrielli L, Ávila S, Aucar ME, Martin DM, Ormaechea GJ, Inga ME, Francone AA, Charles M, Zompa T, Pérez PJ, Lotersztein V, Nuova PJ, Canonero IB, Mahroo OA, Michaelides M, Arno G, Daich Varela M. Nationwide genetic analysis of more than 600 families with inherited eye diseases in Argentina. NPJ Genom Med 2023; 8:8. [PMID: 37217489 DOI: 10.1038/s41525-023-00352-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Accepted: 04/05/2023] [Indexed: 05/24/2023] Open
Abstract
This study corresponds to the first large-scale genetic analysis of inherited eye diseases (IED) in Argentina and describes the comprehensive genetic profile of a large cohort of patients. Medical records of 22 ophthalmology and genetics services throughout 13 Argentinian provinces were analyzed retrospectively. Patients with a clinical diagnosis of an ophthalmic genetic disease and a history of genetic testing were included. Medical, ophthalmological and family history was collected. A total of 773 patients from 637 families were included, with 98% having inherited retinal disease. The most common phenotype was retinitis pigmentosa (RP, 62%). Causative variants were detected in 379 (59%) patients. USH2A, RPGR, and ABCA4 were the most common disease-associated genes. USH2A was the most frequent gene associated with RP, RDH12 early-onset severe retinal dystrophy, ABCA4 Stargardt disease, PROM1 cone-rod dystrophy, and BEST1 macular dystrophy. The most frequent variants were RPGR c.1345 C > T, p.(Arg449*) and USH2A c.15089 C > A, p.(Ser5030*). The study revealed 156/448 (35%) previously unreported pathogenic/likely pathogenic variants and 8 possible founder mutations. We present the genetic landscape of IED in Argentina and the largest cohort in South America. This data will serve as a reference for future genetic studies, aid diagnosis, inform counseling, and assist in addressing the largely unmet need for clinical trials to be conducted in the region.
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Affiliation(s)
| | - José D Luna
- Centro Privado de Ojos Romagosa SA, Córdoba, Argentina
| | - Natalia Labat
- Centro Privado de Ojos Romagosa SA, Córdoba, Argentina
| | | | | | - Evangelina Esposito
- University Clinic Reina Fabiola, Córdoba, Córdoba, Argentina
- Catholic University of Cordoba, Cordoba, Argentina
| | - Agustina Ibañez
- University Clinic Reina Fabiola, Córdoba, Córdoba, Argentina
- Catholic University of Cordoba, Cordoba, Argentina
| | | | | | | | | | | | | | | | - Mauro Visotto
- Instituto Oftalmológico Trelew, Trelew, Chubut, Argentina
| | | | - Emilio Alcoba
- Hospital Materno Infantil Dr Héctor Quintana, Jujuy, Argentina
| | | | - Silvia Ávila
- Facultad de Ciencias Médicas, Universidad Nacional del Comahue, Río Negro, Argentina
| | | | | | | | - M Eugenia Inga
- Organización Medica de Investigación, Buenos Aires, Argentina
| | | | | | - Tamara Zompa
- Charles Centro Oftalmológico, Buenos Aires, Argentina
| | | | | | - Pedro J Nuova
- Ocularyb Oftalmoclinica, Yerba Buena, Tucumán, Argentina
| | | | - Omar A Mahroo
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Michel Michaelides
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Gavin Arno
- Moorfields Eye Hospital, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Malena Daich Varela
- Moorfields Eye Hospital, London, UK.
- UCL Institute of Ophthalmology, University College London, London, UK.
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Hecht I, Weiner C, Kotlyar A, Shoshany N, Pras E. Micro chromosomal deletions at the NYS7 locus and autosomal dominant nystagmus. Exp Eye Res 2023; 230:109459. [PMID: 37001852 DOI: 10.1016/j.exer.2023.109459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/13/2023] [Accepted: 03/25/2023] [Indexed: 03/31/2023]
Abstract
Nystagmus is an ocular condition characterized by bilateral involuntary ocular oscillation which can severely affect vision. When not associated with other ocular or systemic diseases, it is referred to as idiopathic or congenital motor nystagmus (CMN). Genome-wide linkage studies have previously identified several loci associated with CMN, however the genes responsible for some of these loci have yet to be identified. We have examined a large, five-generation family with autosomal dominant CMN. Our purpose was to characterize the clinical manifestations and reveal the molecular basis of the disease in this family. In addition to full ophthalmic examination and imaging, molecular analysis included copy number variation analysis, linkage studies, and Sanger sequencing. Expression analyses of candidate genes was done by real-time PCR. Of the 68 family members, 27 subjects in five-generations had CMN, in line with an autosomal dominant inheritance pattern. Molecular analysis was performed on 27 members, 15 of them affected by CMN. Copy number variation analysis using array comparative genomic hybridization (aCGH) revealed a novel deletion located on 1q32 (NYS7) among affected individuals. Linkage analysis using polymorphic markers demonstrated full segregation with a heterozygous haplotype in all affected patients, with a LOD score of >5. Sanger sequencing of affected subjects revealed a novel deletion of 732,526 bp in the linkage interval. No protein-coding genes exist within the deleted region; however, the deletion disrupts topologically associated domains encompassing the gene NR5A2 and the non-protein coding MIR181A. Both are strongly associated with other genes expressed in the retina such as PROX1, which in turn is also associated with genes related to nystagmus such as PAX6. We therefore hypothesized that the deletion might affect NR5A2 and MIR181A expression, causing CMN. Expression analysis by real-time PCR showed significantly lower expression of NR5A2, and significantly higher expression of PROX1 among patients compared with controls. To conclude, among a large five-generation family with autosomal dominant CMN, a large deletion in the interval of NYS7 was linked with the disease. No protein-coding genes exist inside the deleted region, and so the exact mechanism in which CMN is caused is uncertain. Based on topological association and expression analyses we suggest a possible mechanism for the pathogenesis.
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Affiliation(s)
- Idan Hecht
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Matlow's Ophthalmo-Genetics Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel.
| | - Chen Weiner
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Matlow's Ophthalmo-Genetics Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
| | - Alina Kotlyar
- Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Matlow's Ophthalmo-Genetics Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
| | - Nadav Shoshany
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Matlow's Ophthalmo-Genetics Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
| | - Eran Pras
- Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel; Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel; The Matlow's Ophthalmo-Genetics Laboratory, Department of Ophthalmology, Shamir Medical Center (formerly Assaf-Harofeh), Tzrifin, Israel
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5
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Zeitz C, Roger JE, Audo I, Michiels C, Sánchez-Farías N, Varin J, Frederiksen H, Wilmet B, Callebert J, Gimenez ML, Bouzidi N, Blond F, Guilllonneau X, Fouquet S, Léveillard T, Smirnov V, Vincent A, Héon E, Sahel JA, Kloeckener-Gruissem B, Sennlaub F, Morgans CW, Duvoisin RM, Tkatchenko AV, Picaud S. Shedding light on myopia by studying complete congenital stationary night blindness. Prog Retin Eye Res 2023; 93:101155. [PMID: 36669906 DOI: 10.1016/j.preteyeres.2022.101155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 12/02/2022] [Accepted: 12/05/2022] [Indexed: 01/20/2023]
Abstract
Myopia is the most common eye disorder, caused by heterogeneous genetic and environmental factors. Rare progressive and stationary inherited retinal disorders are often associated with high myopia. Genes implicated in myopia encode proteins involved in a variety of biological processes including eye morphogenesis, extracellular matrix organization, visual perception, circadian rhythms, and retinal signaling. Differentially expressed genes (DEGs) identified in animal models mimicking myopia are helpful in suggesting candidate genes implicated in human myopia. Complete congenital stationary night blindness (cCSNB) in humans and animal models represents an ON-bipolar cell signal transmission defect and is also associated with high myopia. Thus, it represents also an interesting model to identify myopia-related genes, as well as disease mechanisms. While the origin of night blindness is molecularly well established, further research is needed to elucidate the mechanisms of myopia development in subjects with cCSNB. Using whole transcriptome analysis on three different mouse models of cCSNB (in Gpr179-/-, Lrit3-/- and Grm6-/-), we identified novel actors of the retinal signaling cascade, which are also novel candidate genes for myopia. Meta-analysis of our transcriptomic data with published transcriptomic databases and genome-wide association studies from myopia cases led us to propose new biological/cellular processes/mechanisms potentially at the origin of myopia in cCSNB subjects. The results provide a foundation to guide the development of pharmacological myopia therapies.
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Affiliation(s)
- Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France.
| | - Jérome E Roger
- Paris-Saclay Institute of Neuroscience, CERTO-Retina France, CNRS, Université Paris-Saclay, Saclay, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France
| | | | | | - Juliette Varin
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Helen Frederiksen
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Baptiste Wilmet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jacques Callebert
- Service of Biochemistry and Molecular Biology, INSERM U942, Hospital Lariboisière, APHP, Paris, France
| | | | - Nassima Bouzidi
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Frederic Blond
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Stéphane Fouquet
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | | | - Vasily Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, ON, Canada; Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, ON, Canada; Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON, Canada
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France; CHNO des Quinze-Vingts, INSERM-DGOS CIC 1423, Paris, France; Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | | | - Florian Sennlaub
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Catherine W Morgans
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA
| | - Robert M Duvoisin
- Department of Chemical Physiology & Biochemistry, Oregon Health & Science University, Portland, OR, USA
| | - Andrei V Tkatchenko
- Oujiang Laboratory, Zhejiang Laboratory for Regenerative Medicine, Vision and Brain Health, Wenzhou, China; Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University, New York, NY, USA
| | - Serge Picaud
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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Salchow DJ. [Nystagmus in Children - a Survey]. Klin Monbl Augenheilkd 2023; 240:617-635. [PMID: 36827996 DOI: 10.1055/a-2022-1111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
Abstract
Nystagmus describes an involuntary, periodic movement of one or both eyes. About 1/600 children and adolescents have nystagmus, most of them idiopathic infantile nystagmus (IIN), also called "congenital nystagmus", which can be caused by mutations in the FRMD7 gene. Other frequent forms of nystagmus are latent nystagmus, which is usually associated with infantile strabismus, and nystagmus associated with albinism. Sometimes difficult to distinguish in young infants is a sensory nystagmus, where a defect in the visual system reduces vision and causes nystagmus. Causes include retinal dystrophies, congenital stationary night blindness and structural ocular defects including optic nerve hypoplasia or dense bilateral congenital cataracts. Unilateral nystagmus can be the sign of an anterior visual pathway lesion. Seesaw nystagmus may be associated with suprasellar and mesodiencephalic lesions and - rarely - with retinal dystrophies.The ophthalmology plays a key role in identifying the form of nystagmus. Children with new onset nystagmus, with spasmus nutans, with vertical or unilateral nystagmus and those with seesaw nystagmus require neurologic evaluation including imaging of the brain.The treatment of nystagmus depends on the underlying cause. Even minor refractive errors should be corrected, contact lenses offer advantages over glasses.Gabapentin and memantine, possibly also carbonic anhydrase inhibitors, are effective in treating IIN, nystagmus in albinism and sensory nystagmus. Nevertheless, pharmacologic treatment of nystagmus is rarely used in children; the reasons are the limited effects on vision, the need for lifelong therapy, and potential side effects. Eye muscle surgery (Anderson procedure, Kestenbaum procedure) can correct a nystagmus-related anomalous head posture. The concept of "artifical divergence" of Cüppers may help to decrease nystagmus intensity in patients whose nystagmus dampens with convergence. The four-muscle-tenotomy, which involves disinsertion and reinsertion of the horizontal muscles at the original insertion of both eyes, has a proven but limited positive effect on visual acuity.
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Salchow DJ. Nystagmus bei Kindern – eine Übersicht. AUGENHEILKUNDE UP2DATE 2023. [DOI: 10.1055/a-1774-3608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
ZusammenfassungNystagmus ist definiert als unwillkürliche, periodische Bewegung, bei der eines oder beide Augen vom Fixationspunkt wegdriften (sog. Drift). Auf die Drift, die langsame Phase, folgt entweder eine schnelle, refixierende Bewegung (sog. Refixationssakkade oder schnelle Phase) oder eine langsamere Bewegung zur Wiederaufnahme der Fixation. In dieser Übersichtsarbeit sollen die wichtigsten Formen von Nystagmus bei Kindern erörtert werden, für eine Übersicht bei Erwachsenen sei auf 1 verwiesen.
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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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9
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Lu S, Ma M, Mao X, Bacino CA, Jankovic J, Sutton VR, Bartley JA, Wang X, Rosenfeld JA, Beleza-Meireles A, Chauhan J, Pan X, Li M, Liu P, Prescott K, Amin S, Davies G, Wangler MF, Dai Y, Bellen HJ. De novo variants in FRMD5 are associated with developmental delay, intellectual disability, ataxia, and abnormalities of eye movement. Am J Hum Genet 2022; 109:1932-1943. [PMID: 36206744 PMCID: PMC9606480 DOI: 10.1016/j.ajhg.2022.09.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 09/09/2022] [Indexed: 01/25/2023] Open
Abstract
Proteins containing the FERM (four-point-one, ezrin, radixin, and moesin) domain link the plasma membrane with cytoskeletal structures at specific cellular locations and have been implicated in the localization of cell-membrane-associated proteins and/or phosphoinositides. FERM domain-containing protein 5 (FRMD5) localizes at cell adherens junctions and stabilizes cell-cell contacts. To date, variants in FRMD5 have not been associated with a Mendelian disease in OMIM. Here, we describe eight probands with rare heterozygous missense variants in FRMD5 who present with developmental delay, intellectual disability, ataxia, seizures, and abnormalities of eye movement. The variants are de novo in all for whom parental testing was available (six out of eight probands), and human genetic datasets suggest that FRMD5 is intolerant to loss of function (LoF). We found that the fly ortholog of FRMD5, CG5022 (dFrmd), is expressed in the larval and adult central nervous systems where it is present in neurons but not in glia. dFrmd LoF mutant flies are viable but are extremely sensitive to heat shock, which induces severe seizures. The mutants also exhibit defective responses to light. The human FRMD5 reference (Ref) cDNA rescues the fly dFrmd LoF phenotypes. In contrast, all the FRMD5 variants tested in this study (c.340T>C, c.1051A>G, c.1053C>G, c.1054T>C, c.1045A>C, and c.1637A>G) behave as partial LoF variants. In addition, our results indicate that two variants that were tested have dominant-negative effects. In summary, the evidence supports that the observed variants in FRMD5 cause neurological symptoms in humans.
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Affiliation(s)
- Shenzhao Lu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Mengqi Ma
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Xiao Mao
- National Health Commission Key Laboratory for Birth Defect Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China; Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Carlos A Bacino
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Joseph Jankovic
- Parkinson's Disease Center and Movement Disorders Clinic, Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA
| | - V Reid Sutton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - James A Bartley
- Loma Linda University Children's Hospital, Loma Linda, CA 92354, USA
| | - Xueying Wang
- Department of Pediatrics, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710004, China
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics Laboratories, Houston, TX 77021, USA
| | - Ana Beleza-Meireles
- Clinical Genetics Department, St Michael's Hospital, University Hospitals Bristol and Weston, Bristol BS1 3NU, UK
| | - Jaynee Chauhan
- Yorkshire Regional Genetics Service, Leeds Teaching Hospitals NHS Trust, Chapel Allerton Hospital, Leeds LS7 4SA, UK
| | - Xueyang Pan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Megan Li
- Invitae, San Francisco, CA 94103, USA
| | - Pengfei Liu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Baylor Genetics Laboratories, Houston, TX 77021, USA
| | - Katrina Prescott
- Yorkshire Regional Genetics Service, Leeds Teaching Hospitals NHS Trust, Chapel Allerton Hospital, Leeds LS7 4SA, UK
| | - Sam Amin
- Paediatric Neurology Department, Bristol Royal Pediatric Hospital, University Hospitals Bristol and Weston, Bristol BS1 3NU, UK
| | | | - Michael F Wangler
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Yuwei Dai
- National Health Commission Key Laboratory for Birth Defect Research and Prevention, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China; Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China.
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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10
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Aychoua N, Schiff E, Malka S, Tailor VK, Chan HW, Oluonye N, Theodorou M, Moosajee M. Prospective study of pediatric patients presenting with idiopathic infantile nystagmus-Management and molecular diagnostics. Front Genet 2022; 13:977806. [PMID: 36072665 PMCID: PMC9441591 DOI: 10.3389/fgene.2022.977806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 07/18/2022] [Indexed: 11/30/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is an inherited disorder occurring in the first 6 months of life, with no underlying retinal or neurological etiologies and is predominantly caused by mutations in the FRMD7 gene. IIN poses a diagnostic challenge as underlying pre-symptomatic "multisystem" disorders varying from benign to life-threatening should first be ruled out before nystagmus can be labeled as idiopathic. A multidisciplinary approach including multimodal ocular investigations and next-generation sequencing with whole-genome sequencing (WGS) or targeted gene panel testing is required to delineate the exact etiology. We report the clinical and genetic outcomes of 22 patients, from 22 unrelated families of diverse ethnicities, with IIN seen in the ocular genetics service at Moorfields Eye Hospital NHS Foundation Trust between 2016 and 2022. Thirty-six percent (8/22) received a confirmed molecular diagnosis with eight mutations identified in two genes (seven in FRMD7 including one novel variant c.706_707del; p. [Lys236Alafs*66], and one in GPR143). This study expands the mutational spectrum of IIN and highlights the significant role of an integrated care pathway and broader panel testing in excluding underlying pathologies.
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Affiliation(s)
- Nancy Aychoua
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Elena Schiff
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Samantha Malka
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Vijay K Tailor
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Experimental Psychology, University College London, London, United Kingdom
| | - Hwei Wuen Chan
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
- Department of Ophthalmology, National University Hospital, Singapore, Singapore
| | - Ngozi Oluonye
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Maria Theodorou
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Mariya Moosajee
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
- The Francis Crick Institute, London, United Kingdom
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11
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Hassan A, Mir YR, Kuchay RAH. Ocular findings and genomics of X-linked recessive disorders: A review. Indian J Ophthalmol 2022; 70:2386-2396. [PMID: 35791118 PMCID: PMC9426149 DOI: 10.4103/ijo.ijo_252_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Advent of new sequencing technologies and modern diagnostic procedures has opened the door for a deeper understanding of disorders about which little was known previously. Discovery of novel genes, new genetic variants in previously known genes and better techniques of functional validation has immensely contributed to unraveling the molecular basis of genetic disorders. Availability of knockout animal models like the zebrafish and gene editing tools like CRISPR-Cas9 has elucidated the function of many new genes and helped us to better understand the functional consequences of various gene defects. This has also led to better diagnosis and therapeutic interventions. In this context, a good body of research work has been done on X-linked recessive disorders with ocular findings. This review will focus on ocular and genetic findings of these rare disorders. To our knowledge, this is the first comprehensive review encompassing ocular and genomic spectrum of X-linked recessive disorders.
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Affiliation(s)
- Asima Hassan
- Department of Health and Medical Education, Srinagar, Jammu and Kashmir, India
| | - Yaser R Mir
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
| | - Raja A H Kuchay
- Department of Biotechnology, Baba Ghulam Shah Badshah University, Rajouri, Jammu and Kashmir, India
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12
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Tiriac A, Feller MB. Roles of visually evoked and spontaneous activity in the development of retinal direction selectivity maps. Trends Neurosci 2022; 45:529-538. [PMID: 35491255 DOI: 10.1016/j.tins.2022.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/30/2022] [Accepted: 04/05/2022] [Indexed: 11/18/2022]
Abstract
Detecting the direction of motion underlies many visually guided behaviors, from reflexive eye movements to identifying and catching moving objects. A subset of motion sensitive cells are direction selective - responding strongly to motion in one direction and weakly to motion in other directions. In mammals, direction-selective cells are found throughout the visual system, including the retina, superior colliculus, and primary visual cortex. Direction selectivity maps are well characterized in the mouse retina, where the preferred directions of retinal direction-selective cells follow the projections of optic flow, generated by the movements animals make as they navigate their environment. Here, we synthesize recent findings implicating activity-dependent mechanisms in the development of retinal direction selectivity maps, with primary focus on studies in mice, and discuss the implications for the development of direction-selective responses in downstream visual areas.
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Affiliation(s)
- Alexandre Tiriac
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Marla B Feller
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA.
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13
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Huang L, Zhou Y, Chen W, Lin P, Xie Y, He K, Zhang S, Wu Y, Li N. Correlations of FRMD7 gene mutations with ocular oscillations. Sci Rep 2022; 12:9914. [PMID: 35705619 PMCID: PMC9200781 DOI: 10.1038/s41598-022-14144-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 05/11/2022] [Indexed: 11/30/2022] Open
Abstract
Mutations in the FERM domain containing 7 (FRMD7) gene have been proven to be responsible for infantile nystagmus (IN). The purpose of this study is to investigate FRMD7 gene mutations in patients with IN, and to evaluate the nystagmus intensity among patients with and without FRMD7 mutations. The affected males were subdivided into three groups according to whether or not having FRMD7 mutations and the types of mutations. Fifty-two mutations were detected in FRMD7 in 56 pedigrees and 34 sporadic patients with IN, including 28 novel and 24 previous reported mutations. The novel identified mutations further expand the spectrum of FRMD7 mutations. The parameters of nystagmus intensity and the patients’ best corrected visual acuity were not statistically different among the patients with and without identified FRMD7 mutations, and also not different among patients with different mutant types. The FERM-C domain, whose amino acids are encoded by exons 7, 8 and 9, could be the harbor region for most mutations. Loss-of-function is suggested to be the common molecular mechanism for the X-linked infantile nystagmus.
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Affiliation(s)
- Lijuan Huang
- Department of Ophthalmology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, China.,Department of Ophthalmology, Beijing Children's Hospital, Capital Medical University, No 56. Nan Li Shi Rd, Xicheng District, Beijing, 100045, China
| | - Yunyu Zhou
- Department of Ophthalmology, Beijing Children's Hospital, Capital Medical University, No 56. Nan Li Shi Rd, Xicheng District, Beijing, 100045, China
| | - Wencong Chen
- Department of Biostatistics, Vanderbilt University Medical Center, 2525 West End Avenue, Suite 1100, Nashville, TN, 37203, USA
| | - Ping Lin
- Department of Ophthalmology, Xi'an Children's Hospital, Xi'an, 710002, China
| | - Yan Xie
- Department of Ophthalmology, Beijing Children's Hospital, Capital Medical University, No 56. Nan Li Shi Rd, Xicheng District, Beijing, 100045, China
| | - Kaiwen He
- Department of Ophthalmology, Beijing Children's Hospital, Capital Medical University, No 56. Nan Li Shi Rd, Xicheng District, Beijing, 100045, China
| | - Shasha Zhang
- Department of Ophthalmology, Xi'an Children's Hospital, Xi'an, 710002, China
| | - Yuyu Wu
- Department of Ophthalmology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, China.
| | - Ningdong Li
- Department of Ophthalmology, The Second Affiliated Hospital of Fujian Medical University, Quanzhou, 362000, China. .,Department of Ophthalmology, Beijing Children's Hospital, Capital Medical University, No 56. Nan Li Shi Rd, Xicheng District, Beijing, 100045, China. .,Department of Ophthalmology, Xi'an Children's Hospital, Xi'an, 710002, China. .,Key Laboratory of Major Diseases in Children, Ministry of Education, Beijing, 100045, China. .,Department of Ophthalmology, Children's Hospital, Capital Institute of Pediatrics, Beijing, 100020, China.
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14
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Abstract
Retinal circuits transform the pixel representation of photoreceptors into the feature representations of ganglion cells, whose axons transmit these representations to the brain. Functional, morphological, and transcriptomic surveys have identified more than 40 retinal ganglion cell (RGC) types in mice. RGCs extract features of varying complexity; some simply signal local differences in brightness (i.e., luminance contrast), whereas others detect specific motion trajectories. To understand the retina, we need to know how retinal circuits give rise to the diverse RGC feature representations. A catalog of the RGC feature set, in turn, is fundamental to understanding visual processing in the brain. Anterograde tracing indicates that RGCs innervate more than 50 areas in the mouse brain. Current maps connecting RGC types to brain areas are rudimentary, as is our understanding of how retinal signals are transformed downstream to guide behavior. In this article, I review the feature selectivities of mouse RGCs, how they arise, and how they are utilized downstream. Not only is knowledge of the behavioral purpose of RGC signals critical for understanding the retinal contributions to vision; it can also guide us to the most relevant areas of visual feature space. Expected final online publication date for the Annual Review of Vision Science, Volume 8 is September 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Daniel Kerschensteiner
- John F. Hardesty, MD, Department of Ophthalmology and Visual Sciences; Department of Neuroscience; Department of Biomedical Engineering; and Hope Center for Neurological Disorders, Washington University School of Medicine, Saint Louis, Missouri, USA;
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15
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Yu M, Bouhenni R, Kurup SK, He W. Editorial: Genetic Mutations Associated With Ocular Diseases. Front Cell Dev Biol 2022; 9:815522. [PMID: 35004704 PMCID: PMC8741275 DOI: 10.3389/fcell.2021.815522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 12/08/2021] [Indexed: 11/21/2022] Open
Affiliation(s)
- Minzhong Yu
- Ophthalmic Research, Cole Eye Institute, Cleveland Clinic, Cleveland, OH, United States.,Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH, United States.,Department of Ophthalmology, University Hospitals, Case Western Reserve University, Cleveland, OH, United States
| | - Rachida Bouhenni
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown Township, OH, United States.,The Vision Center, Akron Children's Hospital, Akron, OH, United States
| | - Shree K Kurup
- Department of Ophthalmology, University Hospitals, Case Western Reserve University, Cleveland, OH, United States
| | - Wei He
- Department of Ophthalmology, He Eye Specialist Hospital, He University, Shenyang, China
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16
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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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17
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Johnson LL, Kueppers RB, Shen EY, Rudell JC, McLoon LK. Development of Nystagmus With the Absence of MYOD Expression in the Extraocular Muscles. Invest Ophthalmol Vis Sci 2021; 62:3. [PMID: 34617961 PMCID: PMC8504190 DOI: 10.1167/iovs.62.13.3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 09/15/2021] [Indexed: 01/22/2023] Open
Abstract
Purpose Myoblast determination protein 1 (MYOD) is a critical myogenic regulatory factor in muscle development, differentiation, myofiber repair, and regeneration. As the extraocular muscles significantly remodel their myofibers throughout life compared with limb skeletal muscles, we hypothesized that the absence of MYOD would result in their abnormal structure and function. To assess structural and functional changes in the extraocular muscles in MyoD-/- mice, fiber size and number and optokinetic nystagmus reflex (OKN) responses were examined. Methods OKN was measured in MyoD-/- mice and littermate wild-type controls at 3, 6, and 12 months. The extraocular muscles were examined histologically for changes in mean myofiber cross-sectional area, total myofiber number, and nuclei immunostained for PAX7 and PITX2, markers of myogenic precursor cells. Results The MyoD-/- mice developed nystagmus, with both jerk and pendular waveforms, in the absence and in the presence of moving visual stimulation. At 12 months, there were significant losses in mean myofiber cross-sectional area and in total number of orbital layer fibers in all rectus muscles, as well as in global layer fibers in the superior and inferior rectus muscles. Haploinsufficient mice showed abnormal OKN responses. PITX2-positive cell entry into myofibers of the MyoD-/- mice was significantly reduced. Conclusions This study is the first demonstration of the development of nystagmus in the constitutive absence of expression of the muscle-specific transcription factor MYOD. We hypothesize that myofiber loss over time may alter anterograde and/or retrograde communication between the motor nerves and extraocular muscles that are critical for maintaining normalcy of extraocular muscle function.
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Affiliation(s)
- Laura L. Johnson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Graduate Program in Molecular, Cellular, Developmental Biology and Genetics, University of Minnesota, Minneapolis, Minnesota, United States
| | - Rachel B. Kueppers
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Erin Y. Shen
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota Medical School, Minneapolis, Minnesota, United States
| | - Jolene C. Rudell
- Department of Ophthalmology, University of California San Diego, San Diego, California, United States
| | - Linda K. McLoon
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota Medical School, Minneapolis, Minnesota, United States
- Graduate Program in Molecular, Cellular, Developmental Biology and Genetics, University of Minnesota, Minneapolis, Minnesota, United States
- Stem Cell Institute, University of Minnesota Medical School, Minneapolis, Minnesota, United States
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18
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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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19
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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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20
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Development of the vertebrate retinal direction-selective circuit. Dev Biol 2021; 477:273-283. [PMID: 34118273 DOI: 10.1016/j.ydbio.2021.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 05/17/2021] [Accepted: 06/04/2021] [Indexed: 01/13/2023]
Abstract
The vertebrate retina contains an array of neural circuits that detect distinct features in visual space. Direction-selective (DS) circuits are an evolutionarily conserved retinal circuit motif - from zebrafish to rodents to primates - specialized for motion detection. During retinal development, neuronal subtypes that wire DS circuits form exquisitely precise connections with each other to shape the output of retinal ganglion cells tuned for specific speeds and directions of motion. In this review, we follow the chronology of DS circuit development in the vertebrate retina, including the cellular, molecular, and activity-dependent mechanisms that regulate the formation of DS circuits, from cell birth and migration to synapse formation and refinement. We highlight recent findings that identify genetic programs critical for specifying neuronal subtypes within DS circuits and molecular interactions essential for responses along the cardinal axes of motion. Finally, we discuss the roles of DS circuits in visual behavior and in certain human visual disease conditions. As one of the best-characterized circuits in the vertebrate retina, DS circuits represent an ideal model system for studying the development of neural connectivity at the level of individual genes, cells, and behavior.
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21
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Wang XF, Chen H, Huang PJ, Feng ZK, Hua ZQ, Feng X, Han F, Xu XT, Shen RJ, Li Y, Jin ZB, Yu HY. Genotype-Phenotype Analysis and Mutation Spectrum in a Cohort of Chinese Patients With Congenital Nystagmus. Front Cell Dev Biol 2021; 9:627295. [PMID: 33732697 PMCID: PMC7958879 DOI: 10.3389/fcell.2021.627295] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 01/06/2021] [Indexed: 11/28/2022] Open
Abstract
Purpose: Congenital nystagmus (CN) is a genetically and clinically heterogeneous ocular disorder that manifests as involuntary, periodic oscillations of the eyes. To date, only FRMD7 and GPR143 have been reported to be responsible for causing CN. Here, we aimed to identify the disease-causing mutations and describe the clinical features in the affected members in our study. Methods: All the subjects underwent a detailed ophthalmic examination. Direct sequencing of all coding exons and splice site regions in FRMD7 and GPR143 and a mutation assessment were performed in each patient. Results: We found 14 mutations in 14/37 (37.8%) probands, including nine mutations in the FRMD7 gene and five mutations in the GPR143 gene, seven of which are novel, including c.284G>A(R95K), c.964C>T(P322S), c.284+10T>G, c.901T>C (Y301H), and c.2014_2023delTCACCCATGG(S672Pfs*12) in FRMD7, and c.250+1G>C, and c.485G>A (W162*) in GPR143. The mutation detection rate was 87.5% (7/8) of familial vs. 24.1% (7/29) of sporadic cases. Ten mutations in 24 (41.7%) non-syndromic subjects and 4 mutations in 13(30.8%) syndromic subjects were detected. A total of 77.8% (7/9) of mutations in FRMD7 were concentrated within the FERM and FA domains, while all mutations in GPR143 were located in exons 1, 2, 4 and 6. We observed that visual acuity tended to be worse in the GPR143 group than in the FRMD7 group, and no obvious difference in other clinical manifestations was found through comparisons in different groups of patients. Conclusions: This study identified 14 mutations (seven novel and seven known) in eight familial and 29 sporadic patients with congenital nystagmus, expanding the mutational spectrum and validating FRMD7 and GPR143 as mutation hotspots. These findings also revealed a significant difference in the screening rate between different groups of participants, providing new insights for the strategy of genetic screening and early clinical diagnosis of CN.
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Affiliation(s)
- Xiao-Fang Wang
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Hui Chen
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Peng-Juan Huang
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zhuo-Kun Feng
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zi-Qi Hua
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xiang Feng
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Fang Han
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Xiao-Tao Xu
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Ren-Juan Shen
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Yang Li
- Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Zi-Bing Jin
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China.,Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Huan-Yun Yu
- School of Ophthalmology and Optometry, The Eye Hospital, Wenzhou Medical University, Wenzhou, China
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22
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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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23
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Self JE, Lee H. Novel therapeutics in nystagmus: what has the genetics taught us so far? THERAPEUTIC ADVANCES IN RARE DISEASE 2021; 2:2633004021998714. [PMID: 37181109 PMCID: PMC10032456 DOI: 10.1177/2633004021998714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 02/08/2021] [Indexed: 05/16/2023]
Abstract
Nystagmus is a disorder characterised by uncontrolled, repetitive, to-and-fro movement of the eyes. It can occur as a seemingly isolated disorder but is most commonly the first, or most obvious, feature in a host of ophthalmic and systemic disorders. The number of underlying causes is vast, and recent improvements in the provision of genetic testing have shown that many conditions can include nystagmus as a feature, but that phenotypes overlap significantly. Therefore, an increase in the understanding of the genetic causes of nystagmus has shown that successful novel therapeutics for 'nystagmus' can target either specific underlying disorders and mechanisms (aiming to treat the underlying condition as a whole), or a final common pathway (aiming to treat the nystagmus directly). Plain language summary Novel treatments for a disorder of eye movement (nystagmus): what has the genetics taught us so far? Nystagmus is a disorder of eye movement characterised by uncontrolled, to-and-fro movements. It can occur as an isolated disorder, in conditions affecting other parts of the eye, in conditions affecting multiple other parts of the body or secondary to neurological diseases (brain diseases). In recent years, advances in genetic testing methods and increase in genetic testing in healthcare systems have provided a greater understanding of the underlying causes of nystagmus. They have highlighted the bewildering number of genetic causes that can result in what looks like a very similar eye movement disorder.In recent years, new classes of drugs have been developed for some of the causes of nystagmus, and some new drugs have been developed for other conditions which have the potential to work in certain types of nystagmus. For these reasons, genetics has taught us that identifying new possible treatments for nystagmus can either be dependent on identifying the underlying genetic cause and aiming to treat that, or aiming to treat the nystagmus per se by targeting a final common pathway. A toolkit based on specific treatments for specific conditions is more to have meaningful impact on 'nystagmus' than pursuing a panacea based on a 'one size fits all' approach.
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Affiliation(s)
- Jay E Self
- Clinical and Experimental Sciences, Faculty of
Medicine, University of Southampton, Tremona Road, Southampton SO16 6YD,
UK
- University Hospital Southampton, Southampton,
UK
| | - Helena Lee
- Clinical and Experimental Sciences, Faculty of
Medicine, University of Southampton, Southampton, UK
- University Hospital Southampton, Southampton,
UK
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24
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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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25
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Li Y, Jiang L, Wang L, Wang C, Liu C, Guo A, Liu M, Zhang L, Ma C, Zhang X, Gao S, Liu JY. p.His16Arg of STXBP1 (MUNC18-1) Associated With Syntaxin 3B Causes Autosomal Dominant Congenital Nystagmus. Front Cell Dev Biol 2020; 8:591781. [PMID: 33251218 PMCID: PMC7672047 DOI: 10.3389/fcell.2020.591781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/15/2020] [Indexed: 02/04/2023] Open
Abstract
Congenital nystagmus (CN) is an ocular movement disorder manifested as involuntary conjugated binocular oscillation and usually occurs in early infancy. The pathological mechanism underlying CN is still poorly understood. We mapped a novel genetic locus 9q33.1-q34.2 in a larger Chinese family with autosomal dominant CN and identified a variant (c.47A>G/p.His16Arg) of STXBP1 by exome sequencing, which fully co-segregated with the nystagmus phenotype in this family and was absent in 571 healthy unrelated individuals. The STXBP1 encodes syntaxin binding protein 1 (also known as MUNC18-1), which plays a pivotal role in neurotransmitter release. In unc-18 (nematode homolog of MUNC18-1) null Caenorhabditis elegans, we found that the p.His16Arg exhibits a compromised ability to rescue the locomotion defect and aldicarb sensitivity, indicating a functional defect in neurotransmitter release. In addition, we also found an enhanced binding of the p.His16Arg mutant to syntaxin 3B, which is a homolog of syntaxin 1A and specifically located in retinal ribbon synapses. We hypothesize that the variant p.His16Arg of STXBP1 is likely to affect neurotransmitter release in the retina, which may be the underlying etiology of CN in this family. Our results provide a new perspective on understanding the molecular mechanism of CN.
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Affiliation(s)
- Yulei Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China.,School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, China
| | - Lei Jiang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Lejin Wang
- Department of Ophthalmology, Peking University People's Hospital, Beijing, China
| | - Cheng Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Chunjie Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Anyuan Guo
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Mugen Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Luoying Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Cong Ma
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Xianqin Zhang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jing Yu Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
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26
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Borovok N, Weiss C, Sharkia R, Reichenstein M, Wissinger B, Azem A, Mahajnah M. Gene and Protein Expression in Subjects With a Nystagmus-Associated AHR Mutation. Front Genet 2020; 11:582796. [PMID: 33193710 PMCID: PMC7542227 DOI: 10.3389/fgene.2020.582796] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 09/02/2020] [Indexed: 11/24/2022] Open
Abstract
Recently, a consanguineous family was identified in Israel with three children affected by Infantile Nystagmus and Foveal Hypoplasia, following an autosomal recessive mode of inheritance. A homozygous stop mutation c.1861C > T; p.Q621∗ in the aryl hydrocarbon receptor (AHR) gene (AHR; MIM 600253) was identified that co-segregated with the disease in the larger family. AHR is the first gene to be identified causing an autosomal recessive Infantile Nystagmus-related disease in humans. The goal of this study is to delineate the molecular basis of this newly discovered human genetic disorder associated with a rare AHR gene mutation. The gene and protein expression levels of AHR and selected AHR targets from leukocyte cultures of healthy subjects and the patients were analyzed. We observed significant variation between mRNA and protein expression of CYP1A1, CYP1B1, and TiPARP under rest and AHR-induced conditions. The CYP1A1 enzymatic activity in induced leukocytes also differs significantly between the patients and healthy volunteers. Intriguingly, the heterozygous subjects demonstrate CYP1A1 and TiPARP gene and protein expression similar to homozygous patients. In contrast, CYP1B1 inducibility and expression vary between hetero- and homozygous subjects. Similarity and differences in gene and protein expression between heterozygotes and homozygous patients can give us a hint as to which metabolic pathway/s might be involved in the Nystagmus etiology. Thus, we have a unique human model for AHR deficiency that will allow us the opportunity to study the biochemical basis of this rare human mutation, as well as the involvement of AHR in other physiological processes.
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Affiliation(s)
- Natalia Borovok
- Faculty of Life Sciences, School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Celeste Weiss
- Faculty of Life Sciences, School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Rajech Sharkia
- Triangle Research and Development Center, Kafr Qara, Israel.,Beit Berl College, Beit Berl, Israel
| | - Michal Reichenstein
- Faculty of Life Sciences, School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Bernd Wissinger
- Institute for Ophthalmic Research Centre for Ophthalmology, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Abdussalam Azem
- Faculty of Life Sciences, School of Neurobiology, Biochemistry and Biophysics, Tel Aviv University, Tel Aviv, Israel
| | - Muhammad Mahajnah
- Hillel Yaffe Medical Center, Hadera, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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27
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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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28
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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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29
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Structural variations in a non-coding region at 1q32.1 are responsible for the NYS7 locus in two large families. Hum Genet 2020; 139:1057-1064. [PMID: 32248360 PMCID: PMC7406531 DOI: 10.1007/s00439-020-02156-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 03/24/2020] [Indexed: 01/20/2023]
Abstract
Congenital motor nystagmus (CMN) is characterized by early-onset bilateral ocular oscillations without other ocular deficits. To date, mutations in only one gene have been identified to be responsible for CMN, i.e., FRMD7 for X-linked CMN. Four loci for autosomal dominant CMN, including NYS7 (OMIM 614826), have been mapped but the causative genes have yet to be identified. NYS7 was mapped to 1q32.1 based on independent genome-wide linkage scan on two large families with CMN. In this study, mutations in all known protein-coding genes, both intronic sequence with predicted effect and coding sequence, in the linkage interval were excluded by whole-genome sequencing. Then, long-read genome sequencing based on the Nanopore platform was performed with a sample from each of the two families. Two deletions with an overlapping region of 775,699 bp, located in a region without any known protein-coding genes, were identified in the two families in the linkage region. The two deletions as well as their breakpoints were confirmed by Sanger sequencing and co-segregated with CMN in the two families. The 775,699 bp deleted region contains uncharacterized non-protein-coding expressed sequences and pseudogenes but no protein-coding genes. However, Hi-C data predicted that the deletions span two topologically associated domains and probably lead to a change in the 3D genomic architecture. These results provide novel evidence of a strong association between structural variations in non-coding genomic regions and human hereditary diseases like CMN with a potential mechanism involving changes in 3D genome architecture, which provides clues regarding the molecular pathogenicity of CMN.
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30
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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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31
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Sawada J, Katayama T, Tokashiki T, Kikuchi S, Kano K, Takahashi K, Saito T, Adachi Y, Okamoto Y, Yoshimura A, Takashima H, Hasebe N. The First Case of Spinocerebellar Ataxia Type 8 in Monozygotic Twins. Intern Med 2020; 59:277-283. [PMID: 31554751 PMCID: PMC7008061 DOI: 10.2169/internalmedicine.2905-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Spinocerebellar ataxia type 8 (SCA8) is a rare hereditary cerebellar ataxia showing mainly pure cerebellar ataxia. We herein report cases of SCA8 in Japanese monozygotic twins that presented with nystagmus, dysarthria, and limb and truncal ataxia. Their ATXN8OS CTA/CTG repeats were 25/97. They showed similar manifestations, clinical courses, and cerebellar atrophy on magnetic resonance imaging. Some of their pedigrees had nystagmus but not ataxia. These are the first monozygotic twins with SCA8 to be reported anywhere in the world. Although not all subjects with the ATXN8OS CTG expansion develop cerebellar ataxia, these cases suggest the pathogenesis of ATXN8OS repeat expansions in hereditary cerebellar ataxia.
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Affiliation(s)
- Jun Sawada
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Takayuki Katayama
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Takashi Tokashiki
- Department of Neurology, National Hospital Organization Okinawa Hospital, Japan
| | - Shiori Kikuchi
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Kohei Kano
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Kae Takahashi
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Tsukasa Saito
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
| | - Yoshiki Adachi
- Department of Neurology, National Hospital Organization Matsue Medical Center, Japan
| | - Yuji Okamoto
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Akiko Yoshimura
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Hiroshi Takashima
- Department of Neurology and Geriatrics, Kagoshima University Graduate School of Medical and Dental Sciences, Japan
| | - Naoyuki Hasebe
- Division of Neurology, Department of Internal Medicine, Asahikawa Medical University, Japan
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32
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Pu J, Dai S, Gao T, Hu J, Fang Y, Zheng R, Jin C, Zhang B. Nystagmus-related FRMD7 gene influences the maturation and complexities of neuronal processes in human neurons. Brain Behav 2019; 9:e01473. [PMID: 31743612 PMCID: PMC6908866 DOI: 10.1002/brb3.1473] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/15/2019] [Indexed: 02/02/2023] Open
Abstract
AIMS Idiopathic congenital nystagmus (ICN) is an oculomotor disorder caused by the defects in the ocular motor control regions of the brain. Mutations in FRMD7, a member of the FERM family of proteins, associated with cytoskeletal dynamics, are the most frequent causes of X-linked ICN. Previous studies illustrated that FRMD7 is involved in the elongation of neurites during neuronal development; however, almost all the studies were performed on mice cell models. The complexity in the human neuronal network might suggest a unique vulnerability of human neurons to FRMD7 mutations. METHODS Herein, we successfully established human neuronal cell models with FRMD7 mutations, from fibroblasts-reprogrammed neurons (iNs). In these neurons, the complexity of the neuronal processes was measured by the induced ratio, total neurite length, the number of terminals, and the number of maturation neurons. RESULTS The complexity of the neuronal processes was greatly reduced during various reprogramming stages in the presence of FRMD7 mutations. Consistently, the expression of the three main Rho GTPases was significantly increased by FRMD7 mutations. Interestingly, a slightly diverse phenotype is observed in different derived neurons. CONCLUSION We established ideal human neuron models and confirmed that the mutation in FRMD7 influences the maturation and complexities of neuronal processes, which might be involved with the Rho GTPase signaling.
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Affiliation(s)
- Jiali Pu
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Shaobing Dai
- Department of Anesthesiology, Women's Hospital, School Of Medicine, Zhejiang University, Hangzhou, China
| | - Ting Gao
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Jing Hu
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Yi Fang
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Ran Zheng
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Chongyao Jin
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
| | - Baorong Zhang
- Department of Neurology, Second Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, China
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33
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Campbell P, Ellingford JM, Parry NRA, Fletcher T, Ramsden SC, Gale T, Hall G, Smith K, Kasperaviciute D, Thomas E, Lloyd IC, Douzgou S, Clayton-Smith J, Biswas S, Ashworth JL, Black GCM, Sergouniotis PI. Clinical and genetic variability in children with partial albinism. Sci Rep 2019; 9:16576. [PMID: 31719542 PMCID: PMC6851142 DOI: 10.1038/s41598-019-51768-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 09/30/2019] [Indexed: 12/20/2022] Open
Abstract
Individuals who have ocular features of albinism and skin pigmentation in keeping with their familial background present a considerable diagnostic challenge. Timely diagnosis through genomic testing can help avert diagnostic odysseys and facilitates accurate genetic counselling and tailored specialist management. Here, we report the clinical and gene panel testing findings in 12 children with presumed ocular albinism. A definitive molecular diagnosis was made in 8/12 probands (67%) and a possible molecular diagnosis was identified in a further 3/12 probands (25%). TYR was the most commonly mutated gene in this cohort (75% of patients, 9/12). A disease-causing TYR haplotype comprised of two common, functional polymorphisms, TYR c.[575 C > A;1205 G > A] p.[(Ser192Tyr);(Arg402Gln)], was found to be particularly prevalent. One participant had GPR143-associated X-linked ocular albinism and another proband had biallelic variants in SLC38A8, a glutamine transporter gene associated with foveal hypoplasia and optic nerve misrouting without pigmentation defects. Intriguingly, 2/12 individuals had a single, rare, likely pathogenic variant in each of TYR and OCA2 - a significant enrichment compared to a control cohort of 4046 individuals from the 100,000 genomes project pilot dataset. Overall, our findings highlight that panel-based genetic testing is a clinically useful test with a high diagnostic yield in children with partial/ocular albinism.
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Affiliation(s)
- Patrick Campbell
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Jamie M Ellingford
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Neil R A Parry
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK
| | - Tracy Fletcher
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Simon C Ramsden
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Theodora Gale
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Georgina Hall
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | | | | | | | - I Chris Lloyd
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK
| | - Sofia Douzgou
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Jill Clayton-Smith
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Susmito Biswas
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK
| | - Jane L Ashworth
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK
| | - Graeme C M Black
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
| | - Panagiotis I Sergouniotis
- Manchester Centre for Genomic Medicine, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Division of Evolution and Genomic Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
- Manchester Royal Eye Hospital, Manchester Academic Health Science Centre, Manchester University NHS Foundation Trust, Manchester, UK.
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34
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Fraik AK, Quackenbush C, Margres MJ, Comte S, Hamilton DG, Kozakiewicz CP, Jones M, Hamede R, Hohenlohe PA, Storfer A, Kelley JL. Transcriptomics of Tasmanian Devil ( Sarcophilus Harrisii) Ear Tissue Reveals Homogeneous Gene Expression Patterns across a Heterogeneous Landscape. Genes (Basel) 2019; 10:E801. [PMID: 31614864 PMCID: PMC6826840 DOI: 10.3390/genes10100801] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 02/06/2023] Open
Abstract
In an era of unprecedented global change, exploring patterns of gene expression among wild populations across their geographic range is crucial for characterizing adaptive potential. RNA-sequencing studies have successfully characterized gene expression differences among populations experiencing divergent environmental conditions in a wide variety of taxa. However, few of these studies have identified transcriptomic signatures to multivariate, environmental stimuli among populations in their natural environments. Herein, we aim to identify environmental and sex-driven patterns of gene expression in the Tasmanian devil (Sarcophilus harrisii), a critically endangered species that occupies a heterogeneous environment. We performed RNA-sequencing on ear tissue biopsies from adult male and female devils from three populations at the extremes of their geographic range. There were no transcriptome-wide patterns of differential gene expression that would be suggestive of significant, environmentally-driven transcriptomic responses. The general lack of transcriptome-wide variation in gene expression levels across the devil's geographic range is consistent with previous studies that documented low levels of genetic variation in the species. However, genes previously implicated in local adaptation to abiotic environment in devils were enriched for differentially expressed genes. Additionally, three modules of co-expressed genes were significantly associated with either population of origin or sex.
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Affiliation(s)
- Alexandra K Fraik
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA.
| | - Corey Quackenbush
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA.
| | - Mark J Margres
- School of Biological Sciences, Washington State University, Pullman, WA 99164, USA.
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA.
| | - Sebastien Comte
- School of Natural Sciences, Hobart, TAS 7001, Australia.
- Vertebrate Pest Research Unit, NSW Department of Primary Industries, 1447 Forest Road, Orange, NSW 2800, Australia.
| | | | | | - Menna Jones
- School of Natural Sciences, Hobart, TAS 7001, Australia.
| | - Rodrigo Hamede
- School of Natural Sciences, Hobart, TAS 7001, Australia.
| | - Paul A Hohenlohe
- Department of Biological Sciences, University of Idaho, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, ID 83844, USA.
| | - Andrew Storfer
- Department of Biological Sciences, University of Idaho, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, ID 83844, USA.
| | - Joanna L Kelley
- Department of Biological Sciences, University of Idaho, Institute for Bioinformatics and Evolutionary Studies, University of Idaho, 875 Perimeter Drive, Moscow, ID 83844, USA.
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35
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A small gene sequencing panel realises a high diagnostic rate in patients with congenital nystagmus following basic phenotyping. Sci Rep 2019; 9:13229. [PMID: 31519934 PMCID: PMC6744446 DOI: 10.1038/s41598-019-49368-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 07/26/2019] [Indexed: 11/08/2022] Open
Abstract
Nystagmus is a disorder of uncontrolled eye movement and can occur as an isolated trait (idiopathic INS, IINS) or as part of multisystem disorders such as albinism, significant visual disorders or neurological disease. Eighty-one unrelated patients with nystagmus underwent routine ocular phenotyping using commonly available phenotyping methods and were grouped into four sub-cohorts according to the level of phenotyping information gained and their findings. DNA was extracted and sequenced using a broad utility next generation sequencing (NGS) gene panel. A clinical subpanel of genes for nystagmus/albinism was utilised and likely causal variants were prioritised according to methods currently employed by clinical diagnostic laboratories. We determine the likely underlying genetic cause for 43.2% of participants with similar yields regardless of prior phenotyping. This study demonstrates that a diagnostic workflow combining basic ocular phenotyping and a clinically available targeted NGS panel, can provide a high diagnostic yield for patients with infantile nystagmus, enabling access to disease specific management at a young age and reducing the need for multiple costly, often invasive tests. By describing diagnostic yield for groups of patients with incomplete phenotyping data, it also permits the subsequent design of ‘real-world’ diagnostic workflows and illustrates the changing role of genetic testing in modern diagnostic workflows for heterogeneous ophthalmic disorders.
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36
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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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37
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Abstract
Pathological nystagmus is a spontaneous oscillation of the eyes. It is a complex problem with many subtypes and causes ranging from the acute neurological emergency to chronic visual disorders. There is considerable variability in clinical management and patient experience across the UK. The Nystagmus Care Pathway (NCP) is a proposal to provide an evidence-based, consistent minimum standard of care across all eye services for patients with nystagmus. The NCP coordinates expertise from the various team members with a staged approach: 1) pathway entry; 2) nystagmus identification; 3) finding underlying causes/associations; 4) managing causes/associations; 5) managing the nystagmus and its effects; 6) support for patients and families; 7) pathway exit. Orthoptists are ideally placed to coordinate the NCP as they are trained in ocular motility and visual assessment. They are accustomed to providing continuity of care, multidisciplinary working and via the British and Irish Orthoptic Society (BIOS), they can provide consistency of care across the UK. Key performance indicators are proposed.
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Affiliation(s)
- Christopher M Harris
- Orthoptic Department, Royal Eye Infirmary, Plymouth, UK.,Nystagmus Network, Kent, UK.,Psychology Department, Plymouth University, Plymouth, UK
| | - Julie Owen
- Orthoptic Department, Royal Eye Infirmary, Plymouth, UK
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38
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Lee B, Choi DG, Chun BY, Oh EH, Lee YJ, Kim UK, Park JS. A family with a mild form of congenital nystagmus and optic disc coloboma caused by a novel PAX6 mutation. Gene 2019; 705:177-180. [PMID: 30986449 DOI: 10.1016/j.gene.2019.04.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 11/25/2022]
Abstract
Congenital nystagmus (CN) is a heterogeneous disease that shows variable clinical features. There are a few mutations that are known to cause CN. Among them, a PAX6 mutation is known to cause CN with an extremely high frequency of aniridia. Here, we report on a family with an autosomal dominant PAX6 mutation, c.214G > A (p.Gly72Ser.), who presented with CN in the absence of aniridia. This study describes detailed clinical findings, including videonystagmography and fundus photography findings and emphasizes the importance of screening for the PAX6 gene in patients who present with CN in the absence of aniridia, as this will further elucidate the known phenotypes of PAX6-related diseases.
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Affiliation(s)
- Byeonghyeon Lee
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea; School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Deok-Gyun Choi
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Bo Young Chun
- Department of Opthalmology, School of Medicine, Kyungpook National University, Daegu 41944, Republic of Korea
| | - Eun Hye Oh
- Department of Neurology, Pusan National Nuiversity School of Medicine, Pusan National University Yangsan Hospital, Yangsan 50612, Republic of Korea
| | - Yun-Jeong Lee
- Department of Pediatric Neurology, Kyungpook National University Hospital, Daegu 41566, Republic of Korea
| | - Un-Kyung Kim
- Department of Biology, College of Natural Sciences, Kyungpook National University, Daegu 41566, Republic of Korea; School of Life Sciences, BK21 Plus KNU Creative BioResearch Group, Kyungpook National University, Daegu 41566, Republic of Korea
| | - Jin-Sung Park
- Department of Neurology, School of Medicine, Kyungpook National University, Kyungpook National University Chilgok Hospital, Daegu 41404, Republic of Korea.
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39
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Michaud V, Defoort-Dhellemmes S, Drumare I, Pennamen P, Plaisant C, Lasseaux E, Arveiler B. Clinical and molecular findings of FRMD7 related congenital nystagmus as adifferential diagnosis of ocular albinism. Ophthalmic Genet 2019; 40:161-164. [PMID: 30942644 DOI: 10.1080/13816810.2019.1592201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
BACKGROUND Congenital nystagmus is one of the most common neuro-ophthalmological disorders. X chromosome-linked forms are associated with pathogenic variants of the GPR143 and FRMD7 genes. MATERIALS AND METHODS Patients' DNA was analyzed using a next-generation sequencing (NGS) panel of genes involved in albinism and related pathologies (TYR, OCA2, TYRP1, SLC45A2, SLC24A5, C10ORF11, GPR143, SLC38A8, HPS 1 to 10, LYST, MITF, FRMD7) Results: We report a 4 generation family with 5 affected members initially referred for molecular diagnosis of ocular albinism. A missense variant of FRMD7 was found in 3 affected cases and one female carrier. We show that the disease in the affected girl is due to skewed inactivation of the X chromosome. CONCLUSIONS By compiling all the published cases we discuss the variable penetrance among females due to different types of mutation and to X-inactivation.
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Affiliation(s)
- Vincent Michaud
- a Service de Génétique Médicale , CHU de Bordeaux , Bordeaux , France
| | | | - Isabelle Drumare
- b Service d'exploration de la vision et neuro-ophtalmologie , CHRU de Lille , Lille , France
| | - Perrine Pennamen
- a Service de Génétique Médicale , CHU de Bordeaux , Bordeaux , France.,c INSERM U1211, Maladies Rares, Génétique et Métabolisme , Université de Bordeaux , Bordeaux , France
| | - Claudio Plaisant
- a Service de Génétique Médicale , CHU de Bordeaux , Bordeaux , France
| | - Eulalie Lasseaux
- a Service de Génétique Médicale , CHU de Bordeaux , Bordeaux , France
| | - Benoit Arveiler
- a Service de Génétique Médicale , CHU de Bordeaux , Bordeaux , France.,c INSERM U1211, Maladies Rares, Génétique et Métabolisme , Université de Bordeaux , Bordeaux , France
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40
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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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41
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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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Wang Z, Wang M, Wang C, Lu B. Identification and functional characterization of a novel missense mutation in FRMD7 responsible for idiopathic congenital nystagmus. Acta Biochim Biophys Sin (Shanghai) 2019; 51:178-184. [PMID: 30576400 DOI: 10.1093/abbs/gmy161] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Revised: 11/21/2018] [Indexed: 11/14/2022] Open
Abstract
Idiopathic congenital nystagmus (ICN) is a genetically heterogeneous eye movement disorder which seriously reduces childhood visual acuity. X-linked inheritance is the most common pattern, and mutations in FERM domain-containing protein 7 (FRMD7) are the major cause. Here, we recruited a four-generation Chinese family with X-linked ICN for the causative mutational screening of FRMD7. A novel missense variant, c.805 A > C, was identified in the proband. The mutation was confirmed in all the affected individuals but was not detected in unaffected family members or 100 unrelated Chinese male controls. The mutation causes a substitution of lysine to glutamine at position 269 (p.Lys269Gln, K269Q). The FRMD7 mutant inhibits the formation and extension of neurites. Moreover, the mutation disrupts FRMD7 interaction with calcium/calmodulin-dependent serine protein kinase and neurite formation. Together, our data expand the mutation spectrum of FRMD7 causing ICN and provide an insight into the pathogenesis of nystagmus.
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Affiliation(s)
- Zhe Wang
- Department of Ophthalmology, Central Hospital of Zibo, Zibo, China
| | - Min Wang
- Department of Pathology, Jilin Cancer Hospital, Changchun, China
| | - Chengyan Wang
- Department of Ultrasound, Jilin Cancer Hospital, Changchun, China
| | - Boyang Lu
- Department of Ophthalmology, The First Hospital of Jilin University, Changchun, China
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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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Gravier N. [Etiological assessment of a nystagmus in childhood]. J Fr Ophtalmol 2018; 41:868-878. [PMID: 30361175 DOI: 10.1016/j.jfo.2018.04.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 04/04/2018] [Indexed: 11/19/2022]
Abstract
Apart from the latent nystagmus, which arises as a consequence of failure to develop binocular vision, every case of childhood nystagmus needs an etiological assessment. Knowledge of the pathogenesis of the various types of nystagmus guides this assessment, particularly considering the morphological characteristics of the nystagmus. The clinical ophthalmologic examination is complemented by OCT and electrophysiologic testing (ERG, VEP). If this testing is normal, an MRI and genetic assessment are required.
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Affiliation(s)
- N Gravier
- Unité de strabologie-polyclinique de l'Atlantique, avenue Claude-Bernard, BP 40419, 44819 Nantes-Saint-Herblain cedex, France.
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45
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Xiu Y, Yao Y, Yang T, Pan M, Yang H, Fang W, Gu F, Zhao J, Zhu Y. Identification of a novel idiopathic congenital nystagmus‑causing missense mutation, p.G296C, in the FRMD7 gene. Mol Med Rep 2018; 18:2816-2822. [PMID: 30015830 PMCID: PMC6102629 DOI: 10.3892/mmr.2018.9260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 06/12/2018] [Indexed: 11/06/2022] Open
Abstract
Exploring the genetic basis for idiopathic congenital nystagmus is critical for improving our understanding of its molecular pathogenesis. In the present study, direct sequencing using gene specific primers was performed in order to identify the causative mutations in two brothers from a Chinese family who had been diagnosed with idiopathic congenital nystagmus. A comprehensive ophthalmological examination, including eye movement recordings, fundus examination, and retinal optical coherence tomography imaging was also conducted, to characterize the disease phenotype. The results revealed that the two brothers exhibited clear signs of nystagmus without any other ocular anomalies. Direct sequencing revealed a G to T transition (c.886G>T) in exon 9 of the four‑point‑one, ezrin, radixin, moesin domain‑containing 7 (FRMD7) gene, which resulted in a conservative substitution of glycine to cysteine at codon 296 (p.G296C), leading to idiopathic congenital nystagmus in the two affected brothers. c.886G>T is a novel idiopathic congenital nystagmus‑inducing mutation in the FRMD7 gene. This finding expands the spectrum of known gene mutations in idiopathic congenital nystagmus, and may be useful for faster gene diagnosis, prenatal testing, the development of potential gene therapies, and for improving the understanding of the molecular pathogenesis of idiopathic congenital nystagmus.
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Affiliation(s)
- Yanghui Xiu
- The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Yihua Yao
- The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Tanchu Yang
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Meihua Pan
- Eye Institute and Xiamen Eye Center Affiliated Xiamen University, Xiamen, Fujian 361001, P.R. China
| | - Hui Yang
- Department of Ophthalmology, Xiamen Children's Hospital, Xiamen, Fujian 361000, P.R. China
| | - Weifang Fang
- The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
| | - Feng Gu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang 325027, P.R. China
| | - Junzhao Zhao
- The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou, Zhejiang 325000, P.R. China
| | - Yihua Zhu
- The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian 350005, P.R. China
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46
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Kuo YC, He X, Coleman AJ, Chen YJ, Dasari P, Liou J, Biederer T, Zhang X. Structural analyses of FERM domain-mediated membrane localization of FARP1. Sci Rep 2018; 8:10477. [PMID: 29992992 PMCID: PMC6041286 DOI: 10.1038/s41598-018-28692-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Accepted: 06/25/2018] [Indexed: 12/15/2022] Open
Abstract
FARP1 is a multi-domain protein that is involved in regulating neuronal development through interacting with cell surface proteins such as class A Plexins and SynCAM 1. The N-terminal FERM domain in FARP1 is known to both promote membrane localization and mediate these protein interactions, for which the underlying molecular mechanisms remain unclear. Here we determined the crystal structures of the FERM domain of FARP1 from zebrafish, and those of FARP2 (a close homolog of FARP1) from mouse and zebrafish. These FERM domains adopt the three-leaved clover fold that is typical of all FERM domains. Our structures reveal a positively charged surface patch that is highly conserved in the FERM domain of FARP1 and FARP2. In vitro lipid-binding experiments showed that the FARP1 FERM domain binds specifically to several types of phospholipid, which is dependent on the positively charged surface patch. We further determined through cell-based analyses that this surface patch on the FERM domain underlies the localization of FARP1 to the plasma membrane, and that FERM domain interactions recruit it to postsynaptic sites in neurons.
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Affiliation(s)
- Yi-Chun Kuo
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Xiaojing He
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Andrew J Coleman
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Yu-Ju Chen
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Pranathi Dasari
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Jen Liou
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Thomas Biederer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Xuewu Zhang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA.
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47
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Cristofoli F, Devriendt K, Davis EE, Van Esch H, Vermeesch JR. Novel CASK mutations in cases with syndromic microcephaly. Hum Mutat 2018; 39:993-1001. [PMID: 29691940 PMCID: PMC5995665 DOI: 10.1002/humu.23536] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 04/13/2018] [Accepted: 04/17/2018] [Indexed: 11/05/2022]
Abstract
Mutations in CASK cause a wide spectrum of phenotypes in humans ranging from mild X-linked intellectual disability to a severe microcephaly (MC) and pontocerebellar hypoplasia syndrome. Nevertheless, predicting pathogenicity and phenotypic consequences of novel CASK mutations through the exclusive consideration of genetic information and population-based data remains a challenge. Using whole exome sequencing, we identified four novel CASK mutations in individuals with syndromic MC. To understand the functional consequences of the different point mutations on the development of MC and cerebellar defects, we established a transient loss-of-function zebrafish model, and demonstrate recapitulation of relevant neuroanatomical phenotypes. Furthermore, we utilized in vivo complementation studies to demonstrate that the three point mutations confer a loss-of-function effect. This work endorses zebrafish as a tractable model to rapidly assess the effect of novel CASK variants on brain development.
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Affiliation(s)
- Francesca Cristofoli
- Laboratory for Cytogenetics and Genome Research, Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Koen Devriendt
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
| | - Erica E Davis
- Center for Human Disease Modeling, Duke University Medical Center, Durham, North Carolina
| | - Hilde Van Esch
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
- Laboratory for the Genetics of Cognition, Center for Human Genetics, KU Leuven, Leuven, Belgium
| | - Joris R Vermeesch
- Laboratory for Cytogenetics and Genome Research, Center for Human Genetics, KU Leuven, Leuven, Belgium
- Center for Human Genetics, University Hospitals Leuven, Leuven, Belgium
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48
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Trifunović D, Arango-Gonzalez B, Comitato A, Barth M, Del Amo EM, Kulkarni M, Sahaboglu A, Hauck SM, Urtti A, Arsenijevic Y, Ueffing M, Marigo V, Paquet-Durand F. HDAC inhibition in the cpfl1 mouse protects degenerating cone photoreceptors in vivo. Hum Mol Genet 2018; 25:4462-4472. [PMID: 28172811 DOI: 10.1093/hmg/ddw275] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2016] [Revised: 08/05/2016] [Accepted: 08/11/2016] [Indexed: 12/21/2022] Open
Abstract
Cone photoreceptor cell death as it occurs in certain hereditary retinal diseases is devastating, with the affected patients suffering from a loss of accurate and colour vision. Regrettably, these hereditary cone diseases are still untreatable to date. Thus, the identification of substances able to block or restrain cone cell death is of primary importance. We studied the neuroprotective effects of a histone deacetylase inhibitor, Trichostatin A (TSA), in a mouse model of inherited, primary cone degeneration (cpfl1). We show that HDAC inhibition protects cpfl1 cones in vitro, in retinal explant cultures. More importantly, in vivo, a single intravitreal TSA injection significantly increased cone survival for up to 16 days post-injection. In addition, the abnormal, incomplete cone migration pattern in the cpfl1 retina was significantly improved by HDAC inhibition. These findings suggest a crucial role for HDAC activity in primary cone degeneration and highlight a new avenue for future therapy developments for cone dystrophies and retinal diseases associated with impaired cone migration.
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Affiliation(s)
- Dragana Trifunović
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | | | - Antonella Comitato
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
| | - Melanie Barth
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Eva M Del Amo
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland
| | - Manoj Kulkarni
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Ayse Sahaboglu
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Stefanie M Hauck
- Research Unit Protein Science, Helmholtz Center Munich, Neuherberg, Germany
| | - Arto Urtti
- School of Pharmacy, University of Eastern Finland, Kuopio, Finland.,Centre for Drug Research, Division of Pharmaceutical Bioscience, University of Helsinki, Helsinki, Finland
| | - Yvan Arsenijevic
- Unit of Gene Therapy & Stem Cell Biology, Hôpital Ophtalmique Jules Gonin, University of Lausanne, Lausanne, Switzerland
| | - Marius Ueffing
- Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Valeria Marigo
- Department of Life Sciences, University of Modena and Reggio Emilia, Modena, Italy
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50
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Bertsch M, Floyd M, Kehoe T, Pfeifer W, Drack AV. The clinical evaluation of infantile nystagmus: What to do first and why. Ophthalmic Genet 2017; 38:22-33. [PMID: 28177849 DOI: 10.1080/13816810.2016.1266667] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Infantile nystagmus has many causes, some life threatening. We determined the most common diagnoses in order to develop a testing algorithm. METHODS Retrospective chart review. Exclusion criteria were no nystagmus, acquired after 6 months, or lack of examination. DATA COLLECTED pediatric eye examination findings, ancillary testing, order of testing, referral, and final diagnoses. Final diagnosis was defined as meeting published clinical criteria and/or confirmed by diagnostic testing. Patients with a diagnosis not meeting the definition were "unknown." Patients with incomplete testing were "incomplete." Patients with multiple plausible etiologies were "multifactorial." Patients with negative complete workup were "motor." RESULTS A total of 284 charts were identified; 202 met inclusion criteria. The three most common causes were Albinism (19%), Leber Congenital Amaurosis (LCA; 14%), and Non-LCA retinal dystrophy (13%). Anatomic retinal disorders comprised 10%, motor another 10%. The most common first test was MRI (74/202) with a diagnostic yield of 16%. For 28 MRI-first patients, nystagmus alone was the indication; for 46 MRI-first patients other neurologic signs were present. 0/28 nystagmus-only patients had a diagnostic MRI while 14/46 (30%) with neurologic signs did. The yield of ERG as first test was 56%, OCT 55%, and molecular genetic testing 47%. Overall, 90% of patients had an etiology identified. CONCLUSION The most common causes of infantile nystagmus were retinal disorders (56%), however the most common first test was brain MRI. For patients without other neurologic stigmata complete pediatric eye examination, ERG, OCT, and molecular genetic testing had a higher yield than MRI scan. If MRI is not diagnostic, a complete ophthalmologic workup should be pursued.
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Affiliation(s)
- Morgan Bertsch
- a Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research , Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City , Iowa , USA
| | - Michael Floyd
- a Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research , Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City , Iowa , USA.,b HealthPartners , Minneapolis , Minnesota , USA
| | - Taylor Kehoe
- a Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research , Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City , Iowa , USA.,c Physician Assistant Program , University of Iowa , Iowa City , Iowa , USA
| | - Wanda Pfeifer
- a Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research , Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City , Iowa , USA
| | - Arlene V Drack
- a Department of Ophthalmology and Visual Sciences, Wynn Institute for Vision Research , Roy J. and Lucille A. Carver College of Medicine, University of Iowa , Iowa City , Iowa , USA
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