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Jones JL, Burdon KP. Evaluating gap junction variants for a role in pediatric cataract: an overview of the genetic landscape and clinical classification of variants in the GJA3 and GJA8 genes. EXPERT REVIEW OF OPHTHALMOLOGY 2022. [DOI: 10.1080/17469899.2023.2160320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Johanna L Jones
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Kathryn P Burdon
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
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Jin A, Zhao Q, Liu S, Jin ZB, Li S, Xiang M, Zeng M, Jin K. Identification of a New Mutation p.P88L in Connexin 50 Associated with Dominant Congenital Cataract. Front Cell Dev Biol 2022; 10:794837. [PMID: 35531093 PMCID: PMC9068895 DOI: 10.3389/fcell.2022.794837] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 03/29/2022] [Indexed: 11/13/2022] Open
Abstract
Congenital hereditary cataract is genetically heterogeneous and the leading cause of visual impairment in children. Identification of hereditary causes is critical to genetic counselling and family planning. Here, we examined a four-generation Chinese pedigree with congenital dominant cataract and identified a new mutation in GJA8 via targeted exome sequencing. A heterozygous missense mutation c.263C > T, leading to a proline-to-Leucine conversion at the conserved residue 88 in the second transmembrane domain of human connexin 50 (Cx50), was identified in all patients but not in unaffected family members. Functional analyses of the mutation revealed that it disrupted the stability of Cx50 and had a deleterious effect on protein function. Indeed, the mutation compromised normal membrane permeability and gating of ions, and impeded cell migration when overexpressed. Together, our results expand the pathogenic mutation spectrum of Cx50 underlying congenital cataract and lend more support to clinical diagnosis and genetic counseling.
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Affiliation(s)
- Aixia Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingqing Zhao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shuting Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Zi-bing Jin
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
| | - Shuyan Li
- Department of Biochemistry and Biophysics, Peking University Health Science Center, Beijing, China
| | - Mengqing Xiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- *Correspondence: Kangxin Jin, ; Mengqing Xiang, ; Mingbing Zeng,
| | - Mingbing Zeng
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Hainan Eye Hospital, Hainan Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Haikou, China
- *Correspondence: Kangxin Jin, ; Mengqing Xiang, ; Mingbing Zeng,
| | - Kangxin Jin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
- Beijing Institute of Ophthalmology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
- *Correspondence: Kangxin Jin, ; Mengqing Xiang, ; Mingbing Zeng,
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Detection of c.139G>A (D47N) mutation in GJA8 gene in an extended family with inheritance of autosomal dominant zonular cataract without pulverulent opacities by exome sequencing. J Genet 2018. [DOI: 10.1007/s12041-018-0971-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Li J, Xia CH, Wang E, Yao K, Gong X. Screening, genetics, risk factors, and treatment of neonatal cataracts. Birth Defects Res 2017; 109:734-743. [PMID: 28544770 DOI: 10.1002/bdr2.1050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 04/15/2017] [Indexed: 12/21/2022]
Abstract
Neonatal cataracts remain the most common cause of visual loss in children worldwide and have diverse, often unknown, etiologies. This review summarizes current knowledge about the detection, treatment, genetics, risk factors, and molecular mechanisms of congenital cataracts. We emphasize significant progress and topics requiring further study in both clinical cataract therapy and basic lens research. Advances in genetic screening and surgical technologies have improved the diagnosis, management, and visual outcomes of affected children. For example, mutations in lens crystallins and membrane/cytoskeletal components that commonly underlie genetically inherited cataracts are now known. However, many questions still remain regarding the causes, progression, and pathology of neonatal cataracts. Further investigations are also required to improve diagnostic criteria for determining the timing of appropriate interventions, such as the implantation of intraocular lenses and postoperative management strategies, to ensure safety and predictable visual outcomes for children. Birth Defects Research 109:734-743, 2017. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Jinyu Li
- Eye Center, Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Ophthalmology of Zhejiang Province, China
| | - Chun-Hong Xia
- School of Optometry and Vision Science Program, University of California, Berkeley, California, USA
| | - Eddie Wang
- School of Optometry and Vision Science Program, University of California, Berkeley, California, USA
| | - Ke Yao
- Eye Center, Second Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, Zhejiang, China.,Key Laboratory of Ophthalmology of Zhejiang Province, China
| | - Xiaohua Gong
- School of Optometry and Vision Science Program, University of California, Berkeley, California, USA
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Messina-Baas O, Cuevas-Covarrubias SA. Inherited Congenital Cataract: A Guide to Suspect the Genetic Etiology in the Cataract Genesis. Mol Syndromol 2017; 8:58-78. [PMID: 28611546 DOI: 10.1159/000455752] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/05/2016] [Indexed: 01/23/2023] Open
Abstract
Cataracts are the principal cause of treatable blindness worldwide. Inherited congenital cataract (CC) shows all types of inheritance patterns in a syndromic and nonsyndromic form. There are more than 100 genes associated with cataract with a predominance of autosomal dominant inheritance. A cataract is defined as an opacity of the lens producing a variation of the refractive index of the lens. This variation derives from modifications in the lens structure resulting in light scattering, frequently a consequence of a significant concentration of high-molecular-weight protein aggregates. The aim of this review is to introduce a guide to identify the gene involved in inherited CC. Due to the manifold clinical and genetic heterogeneity, we discarded the cataract phenotype as a cardinal sign; a 4-group classification with the genes implicated in inherited CC is proposed. We consider that this classification will assist in identifying the probable gene involved in inherited CC.
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Deng H, Yuan L. Molecular genetics of congenital nuclear cataract. Eur J Med Genet 2013; 57:113-22. [PMID: 24384146 DOI: 10.1016/j.ejmg.2013.12.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2013] [Accepted: 12/22/2013] [Indexed: 01/28/2023]
Abstract
A cataract is defined as opacification of the normally transparent crystalline lens. Congenital cataract (CC) is a type of cataract that presents at birth or during early childhood. CC is one of the most common causes of visual impairment or blindness in children worldwide. Approximately 50% of all CC cases may have a genetic cause which is quite heterogeneous. CC occurs in a variety of morphologic configurations, including polar/subcapsular, nuclear, lamellar, sutural, cortical, membranous/capsular and complete. Nuclear cataract refers to the opacification limited to the embryonic and/or fetal nuclei of the lens. Although congenital nuclear cataract can be caused by multiple factors, genetic mutation remains to be the most common cause. It can be inherited in one of the three patterns: autosomal dominant, autosomal recessive, or X-linked transmission. Autosomal dominant inheritance is the most frequent mode with high penetrance. There may be no obvious correlation between the genotype and phenotype of congenital nuclear cataract. Animal models have been established to study the pathogenesis of congenital nuclear cataract and to identify candidate genes. In this review, we highlight identified genetic mutations that account for congenital nuclear cataract. Our review may be helpful for genetic counseling and prenatal diagnosis.
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Affiliation(s)
- Hao Deng
- Center for Experimental Medicine and Department of Neurology, the Third Xiangya Hospital, Central South University, Tongzipo Road 138, Changsha, Hunan 410013, China.
| | - Lamei Yuan
- Center for Experimental Medicine and Department of Neurology, the Third Xiangya Hospital, Central South University, Tongzipo Road 138, Changsha, Hunan 410013, China
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Abstract
Specimens of the anterior lens capsule with an attached monolayer of lens epithelial cells (LECs) were obtained from patients (n=52) undergoing cataract surgery. Specimens were divided into three groups based on the type of cataract: nuclear cataract, cortical cataract and posterior subcapsular cataract (PSC). Clear lenses (n=11) obtained from donor eyes were used as controls. Expression was studied by immunofluorescence, real-time PCR and Western blot. Statistical analysis was done using the student's t-test. Immunofluorescence results showed punctate localization of Cx43 at the cell boundaries in controls, nuclear cataract and PSC groups. In the cortical cataract group, cytoplasmic pools of Cx43 without any localization at the cell boundaries were observed. Real-time PCR results showed significant up-regulation of Cx43 in nuclear and cortical cataract groups. Western blot results revealed significant increase in protein levels of Cx43 and significant decrease of ZO-1 in all three cataract groups. Protein levels of alpha-catenin were decreased significantly in nuclear and cortical cataract group. There was no significant change in expression of beta-catenin in the cataractous groups. Our findings suggest that ZO-1 and alpha-catenin are important for gap junctions containing Cx43 in the LECs. Alterations in cell junction proteins may play a role during formation of different types of cataract.
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Reis LM, Tyler RC, Muheisen S, Raggio V, Salviati L, Han DP, Costakos D, Yonath H, Hall S, Power P, Semina EV. Whole exome sequencing in dominant cataract identifies a new causative factor, CRYBA2, and a variety of novel alleles in known genes. Hum Genet 2013; 132:761-70. [PMID: 23508780 DOI: 10.1007/s00439-013-1289-0] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/07/2013] [Indexed: 01/05/2023]
Abstract
Pediatric cataracts are observed in 1-15 per 10,000 births with 10-25 % of cases attributed to genetic causes; autosomal dominant inheritance is the most commonly observed pattern. Since the specific cataract phenotype is not sufficient to predict which gene is mutated, whole exome sequencing (WES) was utilized to concurrently screen all known cataract genes and to examine novel candidate factors for a disease-causing mutation in probands from 23 pedigrees affected with familial dominant cataract. Review of WES data for 36 known cataract genes identified causative mutations in nine pedigrees (39 %) in CRYAA, CRYBB1, CRYBB3, CRYGC (2), CRYGD, GJA8 (2), and MIP and an additional likely causative mutation in EYA1; the CRYBB3 mutation represents the first dominant allele in this gene and demonstrates incomplete penetrance. Examination of crystallin genes not yet linked to human disease identified a novel cataract gene, CRYBA2, a member of the βγ-crystallin superfamily. The p.(Val50Met) mutation in CRYBA2 cosegregated with disease phenotype in a four-generation pedigree with autosomal dominant congenital cataracts with incomplete penetrance. Expression studies detected cryba2 transcripts during early lens development in zebrafish, supporting its role in congenital disease. Our data highlight the extreme genetic heterogeneity of dominant cataract as the eleven causative/likely causative mutations affected nine different genes, and the majority of mutant alleles were novel. Furthermore, these data suggest that less than half of dominant cataract can be explained by mutations in currently known genes.
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Affiliation(s)
- Linda M Reis
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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