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Tang Y, Xu J, Lu Y, Zheng T. Three Novel Mutations of Microphthalmos Identified in Two Chinese Families. PHENOMICS (CHAM, SWITZERLAND) 2022; 2:254-260. [PMID: 36939803 PMCID: PMC9590552 DOI: 10.1007/s43657-022-00053-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 03/03/2022] [Accepted: 03/08/2022] [Indexed: 10/18/2022]
Abstract
Genetic alterations are a major cause of microphthalmos, while novel-related genes and mutations in microphthalmos have rarely been explored. To identify the underlying genetic defect responsible for microphthalmos eyes in two three-generation Chinese families, we screened 425 genes involved in common inherited non-syndromic eye diseases with next-generation sequencing-based target capture sequencing of the two probands of two three-generation Chinese families diagnosed with microphthalmos. Variants were filtered and analyzed to identify possible disease-causing variants before Sanger sequencing validation. We enrolled two families with microphthalmos (Family 1: microphthalmos with congenital ocular coloboma and Family 2: simple microphthalmos). Two novel heterozygous mutations, Peroxidasin (PXDN) c.3165C>T (p.Pro1055Pro) and PXDN c.2640C>G (p.Arg880Arg), were found in Family 1, and Crystallin Beta B2 (CRYBB2) c.481G>A (p.Gly161Arg) was found in Family 2, but none of the mutations were found in the unaffected individuals, who were phenotypically normal. Multiple orthologous sequence alignment (MSA) revealed that the CRYBB2 p.Gly161Arg mutation was a deleterious effect mutation. In conclusion, the three novel mutations found in our study extend our current understanding of the genetic basis of microphthalmos and provide early pre-symptomatic diagnosis and emphasize the significance of genetic diagnosis of microphthalmos.
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Affiliation(s)
- Yating Tang
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
| | - Jie Xu
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
| | - Yi Lu
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
| | - Tianyu Zheng
- grid.411079.a0000 0004 1757 8722Department of Ophthalmology and Eye Research Institute, Eye and ENT Hospital of Fudan University, Shanghai, 200031 China
- grid.506261.60000 0001 0706 7839NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, 200031, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, 200031 China
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Xu J, Wang H, Wang A, Xu J, Fu C, Jia Z, Yao K, Chen X. βB2 W151R mutant is prone to degradation, aggregation and exposes the hydrophobic side chains in the fourth Greek Key motif. Biochim Biophys Acta Mol Basis Dis 2020; 1867:166018. [PMID: 33246011 DOI: 10.1016/j.bbadis.2020.166018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 11/14/2020] [Accepted: 11/16/2020] [Indexed: 12/16/2022]
Abstract
Studies have established that congenital cataract is the major cause of blindness in children across the globe. The β-crystallin protein family is the richest and most soluble structural protein in the lens. Their solubility and stability are essential in maintaining lens transparency. In this study, we identified a novel βB2 mutation W151R in a rare progressive cortical congenital cataract family and explored its pathogenesis using purified protein and mutant related cataract-cell models. Due to its low solubility and poor structural stability, the βB2 W151R mutation was prone to aggregation. Moreover, the W151R mutation enhanced the exposure of the hydrophobic side chains in the fourth Greek Key motif, which were readily degraded by trypsin. However, upon the administration of lanosterol, the negative effect of the W151R mutation was reversed. Therefore, lanosterol is a potential therapeutic option for cataracts.
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Affiliation(s)
- Jingjie Xu
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Huaxia Wang
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310020, China
| | - Ailing Wang
- Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310020, China
| | - Jia Xu
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Chenxi Fu
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Zhekun Jia
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China
| | - Ke Yao
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China.
| | - Xiangjun Chen
- Eye Center of the Second Affiliated Hospital, Medical College of Zhejiang University, 88 Jiefang Road, Hangzhou 310009, China; Institute of Translational Medicine, Zhejiang University School of Medicine, Hangzhou 310020, China.
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Ching YH, Yeh JI, Fan WL, Chen KC, Yeh MC, Woon PY, Lee YC. A CRYBB2 mutation in a Taiwanese family with autosomal dominant cataract. J Formos Med Assoc 2018; 118:57-63. [PMID: 29395391 DOI: 10.1016/j.jfma.2018.01.005] [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] [Received: 09/28/2017] [Revised: 12/24/2017] [Accepted: 01/05/2018] [Indexed: 10/18/2022] Open
Abstract
BACKGROUND/PURPOSE To identify the underlying genetic cause of a Taiwanese family with autosomal dominant cerulean cataract. METHODS A three-generation cerulean cataract family with 13 affected and 13 normal was identified. Whole exome sequencing, whole genome single nucleotide polymorphism genotyping and haplotype analysis, and fine mapping using polymorphic short tandem repeat markers were used to identify the causative gene mutation. RESULTS Whole genome single nucleotide polymorphism genotyping and haplotype analysis mapped the candidate disease loci to chromosome 18 and chromosome 22. Polymorphic short tandem repeat markers further narrowed down the disease interval to chromosome 22 between markers D22S1174 and D22S1163. Whole exome sequencing was performed on selected individuals. Polymorphisms detected were filtered based on their genomic positions, allele frequency (<1%), and segregation within the pedigree. Affected individuals were found to be heterozygous carrying a C to T mutation on exon 6 of the CRYBB2 gene (with SNP ID: rs74315489). The mutation was predicted to produce a premature stop mutation Q155X. The mutation is co-segregation across the pedigree and the disease "T" allele was not detected in healthy members of the family and in additional 50 normal controls (100 chromosomes). Phylogenic protein alignment was also performed for the CRYBB2 gene across 68 species ranging from fishes, Sauropsida, Placentalia, carnivores, rodents, and primates with total 56 orthologous genes. The Q155 residue is 100% conserved across the evolutionary tree, indicating its crucial function. CONCLUSION Here we identify the first Taiwanese cerulean cataract family carrying a CRYBB2_Q155X mutation.
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Affiliation(s)
- Yung-Hao Ching
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien, Taiwan
| | - Jih-I Yeh
- Department of Family Medicine, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Wen-Lang Fan
- Whole-Genome Research Core Laboratory of Human Diseases, Chang Gung Memorial Hospital, Keelung, Taiwan
| | - Ko-Chen Chen
- Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Man-Chieh Yeh
- Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan
| | - Peng Yeong Woon
- Department of Molecular Biology and Human Genetics, Tzu Chi University, Hualien, Taiwan
| | - Yuan-Chieh Lee
- Department of Ophthalmology, Buddhist Tzu Chi General Hospital, Hualien, Taiwan; Department of Ophthalmology and Visual Science, Tzu Chi University, Hualien, Taiwan.
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Singh M, Tyagi SC. Genes and genetics in eye diseases: a genomic medicine approach for investigating hereditary and inflammatory ocular disorders. Int J Ophthalmol 2018; 11:117-134. [PMID: 29376001 DOI: 10.18240/ijo.2018.01.20] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 10/31/2017] [Indexed: 12/27/2022] Open
Abstract
Past 25y have witnessed an exponential increase in knowledge and understanding of ocular diseases and their respective genetic underpinnings. As a result, scientists have mapped many genes and their variants that can influence vision and health of our eyes. Based on these findings, it is becoming clear that an early diagnosis employing genetic testing can help evaluate patients' conditions for instituting treatment plan(s) and follow-up care to avoid vision complications later. For example, knowing family history becomes crucial for inherited eye diseases as it can benefit members in family who may have similar eye diseases or predispositions. Therefore, gathering information from an elaborate examination along with complete assessment of past medical illness by ophthalmologists followed by consultation with geneticists can help create a roadmap for making diagnosis and treatment precise and beneficial. In this review, we present an update on ocular genomic medicine that we believe has tremendous potential towards unraveling genetic implications in ocular diseases and patients' susceptibilities. We also discuss translational aspects of genetic ophthalmology and genome engineering that may help advance molecular diagnostics and therapeutics.
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Affiliation(s)
- Mahavir Singh
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, USA
| | - Suresh C Tyagi
- Eye and Vision Science Laboratory, Department of Physiology, University of Louisville School of Medicine, Louisville, Kentucky 40202, 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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