1
|
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.
Collapse
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.
| |
Collapse
|
2
|
Liu F, Wang M, Liao M, Liu L, Jiang X. X-linked FRMD7 gene mutation in idiopathic congenital nystagmus and its role in eye movement: A case report and literature review. FRONTIERS IN OPHTHALMOLOGY 2023; 2:1080869. [PMID: 38983508 PMCID: PMC11182149 DOI: 10.3389/fopht.2022.1080869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Accepted: 12/28/2022] [Indexed: 07/11/2024]
Abstract
Background Idiopathic congenital nystagmus (ICN) is an inherited disorder characterized by uncontrollable binocular conjugating oscillation. X-linked idiopathic congenital nystagmus is one of the most prevalent types of ICN. Elucidation of the genetic mechanisms involved in ICN will enhance our understanding of its molecular etiology. Case presentation We report a girl with uncontrollable binocular oscillation and anomalous head posture, then presented a novel heterozygous missense variant (c.686G>T) within the mutation-rich region of the FERM domain containing 7 (FRMD7) gene in her family member. The girl received occlusion therapy and surgical operation which balanced her binocular vision and corrected the anomalous head posture. Conclusions This is the first report on a mutation (c.686G>T) caused the substitution of Arg (R) with Leu (L) at position 229 (p.R229L) of the FRMD7 protein in a patient with ICN.
Collapse
Affiliation(s)
- Fanfei Liu
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Minjin Wang
- Department of Laboratory Medicine, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Meng Liao
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Longqian Liu
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| | - Xiaoshuang Jiang
- Department of Ophthalmology, West China Hospital of Sichuan University, Chengdu, Sichuan, China
| |
Collapse
|
3
|
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.
Collapse
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.
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
GPR143 Gene Mutations in Five Chinese Families with X-linked Congenital Nystagmus. Sci Rep 2015; 5:12031. [PMID: 26160353 PMCID: PMC4498220 DOI: 10.1038/srep12031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 06/12/2015] [Indexed: 02/07/2023] Open
Abstract
The ocular albinism type I (OA1) is clinically characterized by impaired visual acuity, nystagmus, iris hypopigmentation with translucency, albinotic fundus, and macular hypoplasia together with normally pigmented skin and hair. However, it is easily misdiagnosed as congenital idiopathic nystagmus in some Chinese patients with OA1 caused by the G-protein coupled receptor 143 (GPR143) gene mutations. Mutations in the FERM domain–containing 7 (FRMD7) gene are responsible for the X-linked congenital idiopathic nystagmus. In this study, five Chinese families initially diagnosed as X-linked congenital nystagmus were recruited and patients underwent ophthalmological examinations. After direct sequencing of the FRMD7 and GPR143 genes, five mutations in GPR143 gene were detected in each of the five families, including a novel nonsense mutation of c.333G>A (p.W111X), two novel splicing mutations of c.360+1G>C and c.659-1G>A, a novel small deletion mutation of c.43_50dupGACGCAGC (p.L20PfsX25), and a previously reported missense mutation of c.703G>A (p.E235K). Optical coherence tomography (OCT) examination showed foveal hypoplasia in all the affected patients with nystagmus. Our study further expands the GPR143 mutation spectrum and contributes to the study of GPR143 molecular pathogenesis. Molecular diagnosis and optical coherence tomography (OCT) are two useful tools for differential diagnosis.
Collapse
|
6
|
Oculomotor neurocircuitry, a structural connectivity study of infantile nystagmus syndrome. PLoS One 2015; 10:e0125380. [PMID: 25860806 PMCID: PMC4393090 DOI: 10.1371/journal.pone.0125380] [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: 11/13/2012] [Accepted: 03/24/2015] [Indexed: 11/19/2022] Open
Abstract
Infantile nystagmus syndrome (INS) is one of the leading causes of significant vision loss in children and affects about 1 in 1000 to 6000 births. In the present study, we are the first to investigate the structural pathways of patients and controls using diffusion tensor imaging (DTI). Specifically, three female INS patients from the same family were scanned, two sisters and a mother. Six regions of interest (ROIs) were created manually to analyze the number of tracks. Additionally, three ROI masks were analyzed using TBSS (Tract-Based Spatial Statistics). The number of fiber tracks was reduced in INS subjects, compared to normal subjects, by 15.9%, 13.9%, 9.2%, 18.6%, 5.3%, and 2.5% for the pons, cerebellum (right and left), brainstem, cerebrum, and thalamus. Furthermore, TBSS results indicated that the fractional anisotropy (FA) values for the patients were lower in the superior ventral aspects of the pons of the brainstem than in those of the controls. We have identified some brain regions that may be actively involved in INS. These novel findings would be beneficial to the neuroimaging clinical and research community as they will give them new direction in further pursuing neurological studies related to oculomotor function and provide a rational approach to studying INS.
Collapse
|
7
|
Leguire LE, Kashou NH, Fogt N, Smith MA, Lewis JR, Kulwin R, Rogers GL. Neural circuit involved in idiopathic infantile nystagmus syndrome based on FMRI. J Pediatr Ophthalmol Strabismus 2011; 48:347-56. [PMID: 21261242 DOI: 10.3928/01913913-20110118-03] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2010] [Accepted: 12/30/2010] [Indexed: 12/19/2022]
Abstract
PURPOSE To identify the neural circuitry of idiopathic infantile nystagmus syndrome (INS), characterized by an early onset alternating series of slow and rapid eye movements that can manifest in different waveforms and genetic lines. The neural circuitry of INS is currently unknown. METHODS A novel functional magnetic resonance imaging (fMRI) method, referred to as the null zone fMRI technique, was used to identify the neural circuitry for INS. In the null zone fMRI technique, a gaze position with minimal nystagmus within the null zone was linked to the fMRI "off" condition and a gaze position with robust nystagmus outside of the null zone was linked to the fMRI "on" condition. Eye movements were monitored with an fMRI compatible eye tracker and observed in real time to ensure subject compliance in "on" and "off" states. Subjects with INS (n = 4) included three family members (a mother and two daughters) with presumed autosomal dominant INS, as well as age- and gender-matched normal controls (n = 3). RESULTS Three of four subjects with INS demonstrated significant increased activation of the declive of the cerebellum, whereas no normal subjects under identical conditions showed activation of the declive of the cerebellum. Both groups showed significant activation in the occipital lobe (Brodmann areas 17, 18, 19, and cuneus). CONCLUSION A novel fMRI method demonstrated that the declive of the cerebellum is actively involved in INS. These are the first results to identify the cerebellum, and specifically the declive, as a possible site involved in the ocular motor dysfunction known as INS.
Collapse
Affiliation(s)
- Lawrence E Leguire
- Departments of Ophthalmology, Nationwide Children’s Hospital, Columbus, Ohio, USA
| | | | | | | | | | | | | |
Collapse
|
8
|
Abstract
We review current concepts of nystagmus and saccadic oscillations, applying a pathophysiological approach. We begin by discussing how nystagmus may arise when the mechanisms that normally hold gaze steady are impaired. We then describe the clinical and laboratory evaluation of patients with ocular oscillations. Next, we systematically review the features of nystagmus arising from peripheral and central vestibular disorders, nystagmus due to an abnormal gaze-holding mechanism (neural integrator), and nystagmus occurring when vision is compromised. We then discuss forms of nystagmus for which the pathogenesis is not well understood, including acquired pendular nystagmus and congenital forms of nystagmus. We then summarize the spectrum of saccadic disorders that disrupt steady gaze, from intrusions to flutter and opsoclonus. Finally, we review current treatment options for nystagmus and saccadic oscillations, including drugs, surgery, and optical methods. Examples of each type of nystagmus are provided in the form of figures.
Collapse
Affiliation(s)
- Matthew J Thurtell
- Departments of Neurology and Daroff-Dell'Osso Laboratory, Veterans Affairs Medical Center and University Hospitals, Case Western Reserve University, Cleveland, OH 44106, USA
| | | |
Collapse
|
9
|
Abstract
Congenital Idiopathic Nystagmus (CIN) is genetically heterogeneous. Autosomal dominant, autosomal recessive and X-linked patterns of inheritance have been reported. Linkage analysis has suggested the existence of at least three distinct loci for both autosomal dominant and x-linked forms, although as yet no disease genes have been identified. The pathophysiological mechanisms underlying nystagmus are poorly understood and it is likely that insights may arise from finding and characterizing disease genes. If linkage experiments are used to find "nystagmus genes," their power will depend heavily on accurate phenotyping to avoid misdiagnosis due to masquerading conditions and phenotypic variations within pedigrees.
Collapse
Affiliation(s)
- James Self
- University of Southampton, Southampton, UK.
| | | |
Collapse
|
10
|
Self J, Lotery A. A review of the molecular genetics of congenital Idiopathic Nystagmus (CIN). Ophthalmic Genet 2008; 28:187-91. [PMID: 18161616 DOI: 10.1080/13816810701651233] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Congenital Idiopathic Nystagmus (CIN) is genetically heterogeneous. Autosomal dominant, autosomal recessive and X-linked patterns of inheritance have been reported. Linkage analysis has suggested the existence of at least three distinct loci for both autosomal dominant and X-linked forms, although only one disease gene has been identified (FRMD7, Xq26.2). The pathophysiological mechanisms underlying nystagmus are poorly understood but it is anticipated that characterization of the FRMD7 gene and identification of novel nystagmus genes will provide insights into this condition and the functioning and development of the visual pathways in general.
Collapse
Affiliation(s)
- James Self
- Clinical Neurosciences Division, University of Southampton, Southampton, United Kingdom.
| | | |
Collapse
|
11
|
Zhang B, Xia K, Ding M, Liang D, Liu Z, Pan Q, Hu Z, Wu LQ, Cai F, Xia J. Confirmation and refinement of a genetic locus of congenital motor nystagmus in Xq26.3-q27.1 in a Chinese family. Hum Genet 2004; 116:128-31. [PMID: 15517395 DOI: 10.1007/s00439-004-1188-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Accepted: 08/26/2004] [Indexed: 10/26/2022]
Abstract
Congenital motor nystagmus (CMN), a subtype of nystagmus, may reduce vision or be associated with other, more serious, conditions that limit vision. The genetic basis for CMN is still unknown. To identify a locus for CMN, genotyping and linkage analysis were performed in 22 individuals from a Chinese family with X-linked CMN using markers from X chromosome. The maximum LOD score obtained for microsatellite maker DXS1192 linked the CMN locus in this family to Xq. By haplotype construction the locus for CMN was finally localized to an approximately 4.4-cM region at chromosome Xq26.3-q27.1. The SLC9A6 and FGF13 genes in this region, were selected and screened for mutation in this family, but no mutation was detected.
Collapse
Affiliation(s)
- Baorong Zhang
- Department of Neurology of Second Hospital, Affiliated Zhejiang University, 310009 Hangzhou, China.
| | | | | | | | | | | | | | | | | | | |
Collapse
|