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
|
Rodriguez-Martinez AC, Higgins BE, Tailor-Hamblin V, Malka S, Cheloni R, Collins AM, Bladen J, Henderson R, Moosajee M. Foveal Hypoplasia in CRB1-Related Retinopathies. Int J Mol Sci 2023; 24:13932. [PMID: 37762234 PMCID: PMC10531165 DOI: 10.3390/ijms241813932] [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: 07/25/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/29/2023] Open
Abstract
The CRB1 gene plays a role in retinal development and its maintenance. When disrupted, it gives a range of phenotypes such as early-onset severe retinal dystrophy/Leber congenital amaurosis (EOSRD/LCA), retinitis pigmentosa (RP), cone-rod dystrophy (CORD) and macular dystrophy (MD). Studies in CRB1 retinopathies have shown thickening and coarse lamination of retinal layers resembling an immature retina. Its role in foveal development has not yet been described; however, this retrospective study is the first to report foveal hypoplasia (FH) presence in a CRB1-related retinopathy cohort. Patients with pathogenic biallelic CRB1 variants from Moorfields Eye Hospital, London, UK, were collected. Demographic, clinical data and SD-OCT analyses with FH structural grading were performed. A total of 15 (48%) patients had EOSRD/LCA, 11 (35%) MD, 3 (9%) CORD and 2 (6%) RP. FH was observed in 20 (65%; CI: 0.47-0.79) patients, all of whom were grade 1. A significant difference in BCVA between patients with FH and without was found (p = 0.014). BCVA continued to worsen over time in both groups (p < 0.001), irrespective of FH. This study reports FH in a CRB1 cohort, supporting the role of CRB1 in foveal development. FH was associated with poorer BCVA and abnormal retinal morphology. Nonetheless, its presence did not alter the disease progression.
Collapse
Affiliation(s)
- Ana Catalina Rodriguez-Martinez
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 1LE, UK
| | - Bethany Elora Higgins
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Vijay Tailor-Hamblin
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- UCL Experimental Psychology, London WC1H 0AP, UK
| | - Samantha Malka
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Riccardo Cheloni
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
| | - Alexander Mark Collins
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
| | - John Bladen
- King’s College Hospital NHS Foundation Trust, Strand, London WC2R 2LS, UK;
| | - Robert Henderson
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 1LE, UK
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.C.R.-M.); (B.E.H.); (V.T.-H.); (S.M.); (R.C.); (A.M.C.); (R.H.)
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 1LE, UK
- The Francis Crick Institute, London NW1 1AT, UK
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
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
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|