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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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2
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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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3
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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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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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Choi JH, Shin JH, Seo JH, Jung JH, Choi KD. A start codon mutation of the FRMD7 gene in two Korean families with idiopathic infantile nystagmus. Sci Rep 2015; 5:13003. [PMID: 26268155 PMCID: PMC4534761 DOI: 10.1038/srep13003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/10/2015] [Indexed: 11/09/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is the involuntary oscillation of the eyes with onset in the first few months of life. The most common form of inheritance is X-linked, and mutations in FRMD7 gene are a major cause. To identify the FRMD7 gene mutations associated with X-linked IIN, we performed PCR-based DNA direct sequencing in 4 affected subjects from 2 Korean families. We also assessed structural abnormalities of retina and optic nerve head using optical coherence tomography (OCT). Genetic analysis revealed a A>G transversion at nucleotide c.1, the first base of the start codon. This mutation leads to the loss of the primary start codon ATG for methionine, which is replaced by a triplet GTG for valine. The alternative in-frame start codon is not present around a mutation. OCT revealed the morphological changes within the optic nerve head, including shallow cup depth and small cup-to-disc ratio. In summary, we identified a novel start codon mutation within the FRMD7 gene of 2 Korean families. Our data expands the mutation spectrum of FRMD7 causing IIN. We also demonstrated abnormal developments of afferent system in patients with FRMD7 mutations using OCT, which may help to understand the etiological factor in development of nystagmus.
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Affiliation(s)
- Jae-Hwan Choi
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Je Hyun Seo
- Department of Ophthalmology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Jae-Ho Jung
- Department of Ophthalmology, Pusan National University School of Medicine, Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Kwang-Dong Choi
- Department of Neurology, Pusan National University Hospital, Pusan National University School of Medicine and Biomedical Research Institute, Busan, Korea
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Mehrian-Shai R, Freedman S, Shams S, Doherty J, Slattery W, Hsu NYH, Reichardt JKV, Andalibi A, Toren A. Schwannomas exhibit distinct size-dependent gene-expression patterns. Future Oncol 2015; 11:1751-8. [PMID: 26075443 DOI: 10.2217/fon.15.72] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
AIM Neurofibromatosis type 2 (NF2)-associated vestibular schwannomas have variable size at presentation which presents a unique challenge in NF2 patient management. Therefore, we investigated the molecular signature characteristic of the differences in size for improved individualized precise therapy. MATERIALS & METHODS RNA expression analysis was performed on 15 small and 27 large NF2-associated vestibular schwannoma tumors using a microarray analyzing over 47,000 transcripts. RESULTS A signature of 11 genes was found to be correlated with NF2 tumor size. CONCLUSION We have identified the genetic hallmark that differentiates large NF2-associated tumors from smaller tumors. This is the first time that these genes have been shown to be the hallmark for NF2 tumor size.
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Affiliation(s)
- Ruty Mehrian-Shai
- Department of Pediatric Hemato-Oncology, The Cancer Research Center, Sheba Medical Center, 2 Sheba Road, Ramat Gan, 52621, Israel
| | - Shany Freedman
- Department of Pediatric Hemato-Oncology, The Cancer Research Center, Sheba Medical Center, 2 Sheba Road, Ramat Gan, 52621, Israel
| | - Soheil Shams
- BioDiscovery, 5155 W Rosecrans Ave # 310, Hawthorne, CA 90250, USA
| | - Joni Doherty
- Head & Neck Surgery, University of California, San Diego School of Medicine, 9500 Gilman Dr, La Jolla, CA 92093, USA
| | - William Slattery
- Department of Clinical Studies, House Ear Institute, 2100 W 3rd St #500, Los Angeles, CA 90057, USA
| | | | - Juergen K V Reichardt
- Division of Tropical Health & Medicine, James Cook University, Townsville, QLD, Australia
| | - Ali Andalibi
- Stony Brook University, Stony Brook, NY 11794, USA
| | - Amos Toren
- Department of Pediatric Hemato-Oncology, The Cancer Research Center, Sheba Medical Center, 2 Sheba Road, Ramat Gan, 52621, Israel
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Watkins RJ, Patil R, Goult BT, Thomas MG, Gottlob I, Shackleton S. A novel interaction between FRMD7 and CASK: evidence for a causal role in idiopathic infantile nystagmus. Hum Mol Genet 2013; 22:2105-18. [PMID: 23406872 PMCID: PMC3633374 DOI: 10.1093/hmg/ddt060] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is a genetically heterogeneous disorder of eye movement that can be caused by mutations in the FRMD7 gene that encodes a FERM domain protein. FRMD7 is expressed in the brain and knock-down studies suggest it plays a role in neurite extension through modulation of the actin cytoskeleton, yet little is known about its precise molecular function and the effects of IIN mutations. Here, we studied four IIN-associated missense mutants and found them to have diverse effects on FRMD7 expression and cytoplasmic localization. The C271Y mutant accumulates in the nucleus, possibly due to disruption of a nuclear export sequence located downstream of the FERM-adjacent domain. While overexpression of wild-type FRMD7 promotes neurite outgrowth, mutants reduce this effect to differing degrees and the nuclear localizing C271Y mutant acts in a dominant-negative manner to inhibit neurite formation. To gain insight into FRMD7 molecular function, we used an IP-MS approach and identified the multi-domain plasma membrane scaffolding protein, CASK, as a FRMD7 interactor. Importantly, CASK promotes FRMD7 co-localization at the plasma membrane, where it enhances CASK-induced neurite length, whereas IIN-associated FRMD7 mutations impair all of these features. Mutations in CASK cause X-linked mental retardation. Patients with C-terminal CASK mutations also present with nystagmus and, strikingly, we show that these mutations specifically disrupt interaction with FRMD7. Together, our data strongly support a model whereby CASK recruits FRMD7 to the plasma membrane to promote neurite outgrowth during development of the oculomotor neural network and that defects in this interaction result in nystagmus.
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Affiliation(s)
- Rachel J Watkins
- Department of Biochemistry, University of Leicester, Leicester, UK
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Xiao X, Li S, Guo X, Zhang Q. A novel locus for autosomal dominant congenital motor nystagmus mapped to 1q31-q32.2 between D1S2816 and D1S2692. Hum Genet 2011; 131:697-702. [PMID: 22065086 DOI: 10.1007/s00439-011-1113-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Accepted: 10/29/2011] [Indexed: 10/15/2022]
Abstract
Congenital motor nystagmus (CMN) is characterized by bilateral involuntary ocular oscillation without any other underlying ocular or systemic diseases. An autosomal dominant CMN was identified in a large Chinese family where all patients had nystagmus since infancy. The nystagmus in the family is independent of any known ocular or systemic diseases. After exclusion of known CMN loci, a genome-wide scan was performed by genotyping microsatellite markers at about 10 cM intervals, together with two-point linkage analysis. Exome sequencing was used to screen coding exons of well-annotated genes. Sanger-dideoxy sequencing was used to verify candidate variations inside the linkage interval. Congenital motor nystagmus in this family shows linkage to markers in a 11.39 Mb (12.1 cM) region on chromosome 1q31-q32.2 between D1S2816 and D1S2692. All nine markers in the linkage interval gave positive lod scores, with D1S2655 and D1S2636 yielding lod scores of 5.16 and 5.18, respectively, at θ = 0. No causative mutation in the linkage interval was identified by exome sequencing of gDNA from four patients. A linkage study of additional families and further analysis of candidate genes may ultimately lead to identification of the gene responsible for dominantly inherited CMN.
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Affiliation(s)
- Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, 510060 Guangzhou, China.
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The Role of FRMD7 in Idiopathic Infantile Nystagmus. J Ophthalmol 2011; 2012:460956. [PMID: 21904664 PMCID: PMC3163398 DOI: 10.1155/2012/460956] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2011] [Accepted: 06/20/2011] [Indexed: 11/21/2022] Open
Abstract
Idiopathic infantile nystagmus (IIN) is an inherited disorder in which the nystagmus arises independently of any other symptoms, leading to the speculation that the disorder represents a primary defect in the area of the brain responsible for ocular motor control. The inheritance patterns are heterogeneous, however the most common form is X-linked. FRMD7 resides at Xq26-27 and approximately 50% of X-linked IIN families map to this region. Currently 45 mutations within FRMD7 have been associated with IIN, confirming the importance of FRMD7 in the pathogenesis of the disease. Although mutations in FRMD7 are known to cause IIN, very little is known about the function of the protein. FRMD7 contains a conserved N-terminal FERM domain suggesting that it may provide a link between the plasma membrane and actin cytoskeleton. Limited studies together with the knowledge of the function of other FERM domain containing proteins, suggest that FRMD7 may play a role in membrane extension during neuronal development through remodeling of the actin cytoskeleton.
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