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Ma MF, Li LB, Pei YQ, Cheng Z. Use of high-throughput targeted exome sequencing in genetic diagnosis of Chinese family with congenital cataract. Int J Ophthalmol 2016; 9:650-4. [PMID: 27275416 DOI: 10.18240/ijo.2016.05.02] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 07/28/2015] [Indexed: 01/19/2023] Open
Abstract
AIM To identify disease-causing mutation in a congenital cataract family using enrichment of targeted genes combined with next-generation sequencing. METHODS A total of 371 known genes related to inherited eye diseases of the proband was selected and captured, followed by high-throughput sequencing. The sequencing data were analyzed by established bioinformatics pipeline. Validation was performed by Sanger sequencing. RESULTS A recurrent heterozygous non-synonymous mutation c.130G>A (p.V44M) in the GJA3 gene was identified in the proband. The result was confirmed by Sanger sequencing. The mutation showed co-segregation with the disease phenotype in the family but was not detected in unaffected controls. CONCLUSION Targeted exome sequencing is a rapid, high-throughput and cost-efficient method for screening known genes and could be applied to the routine gene diagnosis of congenital cataract.
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Affiliation(s)
- Ming-Fu Ma
- Key Laboratory of Birth Defects and Reproductive Health of the National Health and Family Planning Commission (Chongqing Population and Family Planning Science and Technology Research Institute), Chongqing 400020, China
| | - Lian-Bing Li
- Key Laboratory of Birth Defects and Reproductive Health of the National Health and Family Planning Commission (Chongqing Population and Family Planning Science and Technology Research Institute), Chongqing 400020, China
| | - Yun-Qi Pei
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China
| | - Zhi Cheng
- Department of Cell Biology and Genetics, Chongqing Medical University, Chongqing 400016, China
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Ma AS, Grigg JR, Ho G, Prokudin I, Farnsworth E, Holman K, Cheng A, Billson FA, Martin F, Fraser C, Mowat D, Smith J, Christodoulou J, Flaherty M, Bennetts B, Jamieson RV. Sporadic and Familial Congenital Cataracts: Mutational Spectrum and New Diagnoses Using Next-Generation Sequencing. Hum Mutat 2016; 37:371-84. [PMID: 26694549 PMCID: PMC4787201 DOI: 10.1002/humu.22948] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 12/14/2015] [Indexed: 12/13/2022]
Abstract
Congenital cataracts are a significant cause of lifelong visual loss. They may be isolated or associated with microcornea, microphthalmia, anterior segment dysgenesis (ASD) and glaucoma, and there can be syndromic associations. Genetic diagnosis is challenging due to marked genetic heterogeneity. In this study, next-generation sequencing (NGS) of 32 cataract-associated genes was undertaken in 46 apparently nonsyndromic congenital cataract probands, around half sporadic and half familial cases. We identified pathogenic variants in 70% of cases, and over 68% of these were novel. In almost two-thirds (20/33) of these cases, this resulted in new information about the diagnosis and/or inheritance pattern. This included identification of: new syndromic diagnoses due to NHS or BCOR mutations; complex ocular phenotypes due to PAX6 mutations; de novo autosomal-dominant or X-linked mutations in sporadic cases; and mutations in two separate cataract genes in one family. Variants were found in the crystallin and gap junction genes, including the first report of severe microphthalmia and sclerocornea associated with a novel GJA8 mutation. Mutations were also found in rarely reported genes including MAF, VIM, MIP, and BFSP1. Targeted NGS in presumed nonsyndromic congenital cataract patients provided significant diagnostic information in both familial and sporadic cases.
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Affiliation(s)
- Alan S. Ma
- Eye Genetics ResearchThe Children's Hospital at WestmeadSave Sight InstituteChildren's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
- Department of Clinical GeneticsThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of Paediatrics and Child Healthand Discipline of Genetic MedicineSydney Medical SchoolUniversity of SydneyNew South WalesAustralia
| | - John R. Grigg
- Eye Genetics ResearchThe Children's Hospital at WestmeadSave Sight InstituteChildren's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
- Department of OphthalmologyThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of OphthalmologySydney Medical SchoolUniversity of SydneyNew South WalesAustralia
| | - Gladys Ho
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Department of Molecular GeneticsThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
| | - Ivan Prokudin
- Eye Genetics ResearchThe Children's Hospital at WestmeadSave Sight InstituteChildren's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
| | - Elizabeth Farnsworth
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Department of Molecular GeneticsThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
| | - Katherine Holman
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Department of Molecular GeneticsThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
| | - Anson Cheng
- Eye Genetics ResearchThe Children's Hospital at WestmeadSave Sight InstituteChildren's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
| | - Frank A. Billson
- Eye Genetics ResearchThe Children's Hospital at WestmeadSave Sight InstituteChildren's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
- Department of OphthalmologyThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of OphthalmologySydney Medical SchoolUniversity of SydneyNew South WalesAustralia
| | - Frank Martin
- Department of OphthalmologyThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of OphthalmologySydney Medical SchoolUniversity of SydneyNew South WalesAustralia
| | - Clare Fraser
- Discipline of OphthalmologySydney Medical SchoolUniversity of SydneyNew South WalesAustralia
| | - David Mowat
- Department of Medical GeneticsSydney Children's HospitalSydneyNew South WalesAustralia
| | - James Smith
- Department of OphthalmologyThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
| | - John Christodoulou
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of Paediatrics and Child Healthand Discipline of Genetic MedicineSydney Medical SchoolUniversity of SydneyNew South WalesAustralia
| | - Maree Flaherty
- Eye Genetics ResearchThe Children's Hospital at WestmeadSave Sight InstituteChildren's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
- Department of OphthalmologyThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of OphthalmologySydney Medical SchoolUniversity of SydneyNew South WalesAustralia
| | - Bruce Bennetts
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of Paediatrics and Child Healthand Discipline of Genetic MedicineSydney Medical SchoolUniversity of SydneyNew South WalesAustralia
- Department of Molecular GeneticsThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
| | - Robyn V. Jamieson
- Eye Genetics ResearchThe Children's Hospital at WestmeadSave Sight InstituteChildren's Medical Research InstituteUniversity of SydneySydneyNew South WalesAustralia
- Department of Clinical GeneticsThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Western Sydney Genetics ProgramThe Children's Hospital at WestmeadSydneyNew South WalesAustralia
- Discipline of Paediatrics and Child Healthand Discipline of Genetic MedicineSydney Medical SchoolUniversity of SydneyNew South WalesAustralia
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Javadiyan S, Craig JE, Souzeau E, Sharma S, Lower KM, Pater J, Casey T, Hodson T, Burdon KP. Recurrent mutation in the crystallin alpha A gene associated with inherited paediatric cataract. BMC Res Notes 2016; 9:83. [PMID: 26867756 PMCID: PMC4750205 DOI: 10.1186/s13104-016-1890-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 01/27/2016] [Indexed: 12/18/2022] Open
Abstract
Background Cataract is a major cause of childhood blindness worldwide. The purpose of this study was to determine the genetic cause of paediatric cataract in a South Australian family with a bilateral lamellar paediatric cataract displaying variable phenotypes. Case presentation Fifty-one genes implicated in congenital cataract in human or mouse were sequenced in an affected individual from an Australian (Caucasian) family using a custom Ampliseq library on the Ion Torrent Personal Genome Machine. Reads were mapped against the human genome (hg19) and variants called with the Torrent Suite software. Variants were annotated to dbSNP 137 using Ion Reporter (IR 1.6.2) and were prioritised for validation if they were novel or rare and were predicted to be protein changing. We identified a previously reported oligomerization disrupting mutation, c.62G > A (p.R21Q), in the Crystallin alpha A (CRYAA) gene segregating in this three generation family. No other novel or rare coding mutations were detected in the known cataract genes sequenced. Microsatellite markers were used to compare the haplotypes between the family reported here and a previously published family with the same segregating mutation. Haplotype analysis indicated a potential common ancestry between the two South Australian families with this mutation. The work strengthens the genotype-phenotype correlations between this functional mutation in the crystallin alpha A (CRYAA) gene and paediatric cataract. Conclusion The p.R21Q mutation is the most likely cause of paediatric cataract in this family. The recurrence of this mutation in paediatric cataract families is likely due to a familial relationship. Electronic supplementary material The online version of this article (doi:10.1186/s13104-016-1890-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Shari Javadiyan
- Department of Ophthalmology, School of Medicine, Flinders Medical Centre, Flinders University, Rm 4D 111.1, Flinders Dr, Bedford Park, Adelaide, 5042, Australia.
| | - Jamie E Craig
- Department of Ophthalmology, School of Medicine, Flinders Medical Centre, Flinders University, Rm 4D 111.1, Flinders Dr, Bedford Park, Adelaide, 5042, Australia.
| | - Emmanuelle Souzeau
- Department of Ophthalmology, School of Medicine, Flinders Medical Centre, Flinders University, Rm 4D 111.1, Flinders Dr, Bedford Park, Adelaide, 5042, Australia.
| | - Shiwani Sharma
- Department of Ophthalmology, School of Medicine, Flinders Medical Centre, Flinders University, Rm 4D 111.1, Flinders Dr, Bedford Park, Adelaide, 5042, Australia.
| | - Karen M Lower
- Department of Haematology and Genetic Pathology, School of Medicine, Flinders University, Adelaide, Australia.
| | - John Pater
- Ophthalmology Department, Women's and Children's Hospital, Adelaide, Australia.
| | - Theresa Casey
- Ophthalmology Department, Women's and Children's Hospital, Adelaide, Australia.
| | | | - Kathryn P Burdon
- Department of Ophthalmology, School of Medicine, Flinders Medical Centre, Flinders University, Rm 4D 111.1, Flinders Dr, Bedford Park, Adelaide, 5042, Australia. .,Menzies Institute for Medical Research, University of Tasmania, Hobart, Australia.
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Complex translocation t(1;12;14)(q42;q14;q32) and HMGA2 deletion in a fetus presenting growth delay and bilateral cataracts. Eur J Med Genet 2015; 58:591-6. [PMID: 26386246 DOI: 10.1016/j.ejmg.2015.09.006] [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] [Received: 02/20/2015] [Revised: 09/15/2015] [Accepted: 09/15/2015] [Indexed: 11/20/2022]
Abstract
We report the prenatal detection of a de novo unbalanced complex chromosomal rearrangement (CCR), in a fetus with growth delay and bilateral cataracts. Standard karyotype and FISH analyses on amniotic fluid revealed a complex de novo translocation, resulting in a 46,XY,t(1;12;14)(q42;q14;q32) karyotype. CGH-array showed a significant deletion of 387 kb at 12q14.3, at a distance of only 200-700 kb from the breakpoint at 12q14, which encompassed the HMGA2 gene and occurred de novo. Although 12q14 microdeletions are associated with growth delay in several reports in the literature, we present here the smallest deletion prenatally detected, and we detail the clinical description of the fetus. The correlation between cataracts and this complex genotype is puzzling. Among the genes disrupted by the breakpoint in 12q14, GRIP1 has been associated with abnormal eye development in mice, including lens degeneration. Interestingly, HMGA2 is expressed in the mouse's developing lens, and its expression is decreased in lens of elderly humans, correlated with the severity of lens opacity. In this report, we refine the link between HMGA2 loss of function and growth delay during prenatal development. We also discuss the correlation between cataracts and genotype in this unbalanced CCR case of unexpected complexity.
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Pasutto F, Mauri L, Popp B, Sticht H, Ekici A, Piozzi E, Bonfante A, Penco S, Schlötzer-Schrehardt U, Reis A. Whole exome sequencing reveals a novel de novo FOXC1 mutation in a patient with unrecognized Axenfeld–Rieger syndrome and glaucoma. Gene 2015; 568:76-80. [DOI: 10.1016/j.gene.2015.05.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/17/2015] [Accepted: 05/07/2015] [Indexed: 02/03/2023]
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Deml B, Reis LM, Muheisen S, Bick D, Semina EV. EFTUD2 deficiency in vertebrates: Identification of a novel human mutation and generation of a zebrafish model. ACTA ACUST UNITED AC 2015; 103:630-40. [PMID: 26118977 DOI: 10.1002/bdra.23397] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/30/2015] [Accepted: 05/26/2015] [Indexed: 12/17/2022]
Abstract
BACKGROUND Congenital microphthalmia and coloboma are severe developmental defects that are frequently associated with additional systemic anomalies and display a high level of genetic heterogeneity. METHODS To identify the pathogenic variant in a patient with microphthalmia, coloboma, retinal dystrophy, microcephaly, and other features, whole exome sequencing analysis of the patient and parental samples was undertaken. To further explore the identified variant/gene, expression and functional studies in zebrafish were performed. RESULTS Whole exome sequencing revealed a de novo variant, c.473_474delGA, p.(Arg158Lysfs*4), in EFTUD2 which encodes a component of the spliceosome complex. Dominant mutations in EFTUD2 cause Mandibulofacial Dysostosis, Guion-Almeida type, which does not involve microphthalmia, coloboma, or retinal dystrophy; analysis of genes known to cause these ocular phenotypes identified several variants of unknown significance but no causal alleles in the affected patient. Zebrafish eftud2 demonstrated high sequence conservation with the human gene and broad embryonic expression. TALEN-mediated disruption was employed to generate a c.378_385 del, p.(Ser127Aspfs*23) truncation mutation in eftud2. Homozygous mutants displayed a reduced head size, small eye, curved body, and early embryonic lethality. Apoptosis assays demonstrated a striking increase in terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL)-positive cells in the developing brain, eye, spinal cord, and other tissues starting at 30 hours postfertilization. CONCLUSION This study reports a novel mutation in EFTUD2 in a Mandibulofacial Dysostosis, Guion-Almeida type patient with unusual ocular features and the generation of a first animal model of eftud2 deficiency. The severe embryonic phenotype observed in eftud2 mutants indicates an important conserved role during development of diverse tissues in vertebrates.
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Affiliation(s)
- Brett Deml
- Department of Pediatrics and Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin.,Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Linda M Reis
- Department of Pediatrics and Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Sanaa Muheisen
- Department of Pediatrics and Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - David Bick
- Department of Pediatrics and Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | - Elena V Semina
- Department of Pediatrics and Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin.,Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
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Schilter KF, Reis LM, Sorokina EA, Semina EV. Identification of an Alu-repeat-mediated deletion of OPTN upstream region in a patient with a complex ocular phenotype. Mol Genet Genomic Med 2015; 3:490-9. [PMID: 26740941 PMCID: PMC4694134 DOI: 10.1002/mgg3.159] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 05/05/2015] [Accepted: 05/08/2015] [Indexed: 12/14/2022] Open
Abstract
Genetic causes of ocular conditions remain largely unknown. To reveal the molecular basis for a congenital ocular phenotype associated with glaucoma we performed whole‐exome sequencing (WES) and whole‐genome copy number analyses of patient DNA. WES did not identify a causative variant. Copy number variation analysis identified a deletion of 10p13 in the patient and his unaffected father; the deletion breakpoint contained a single 37‐bp sequence that is normally present in two distinct Alu repeats separated by ~181 kb. The deletion removed part of the upstream region of optineurin (OPTN) as well as the upstream sequence and two coding exons of coiled‐coil domain containing 3 (CCDC3); analysis of the patient's second allele showed normal OPTN and CCDC3 sequences. Studies of zebrafish orthologs identified expression in the developing eye for both genes. OPTN is a known factor in dominant adult‐onset glaucoma and Amyotrophic Lateral Sclerosis (ALS). The deletion eliminates 98 kb of the OPTN upstream sequence leaving only ~1 kb of the proximal promoter region. Comparison of transcriptional activation capability of the 3 kb normal and the rearranged del(10)(p13) OPTN promoter sequences demonstrated a statistically significant decrease for the deleted allele; sequence analysis of the entire deleted region identified multiple conserved elements with possible cis‐regulatory activity. Additional screening of CCDC3 indicated that heterozygous loss‐of‐function alleles are unlikely to cause congenital ocular disease. In summary, we report the first regulatory region deletion involving OPTN, caused by Alu‐mediated nonallelic homologous recombination and possibly contributing to the patient's ocular phenotype. In addition, our data indicate that Alu‐mediated rearrangements of the OPTN upstream region may represent a new source of affected alleles in human conditions. Evaluation of the upstream OPTN sequences in additional ocular and ALS patients may help to determine the role of this region, if any, in human disease.
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Affiliation(s)
- Kala F Schilter
- Department of Pediatrics and Children's Research InstituteMedical College of WisconsinMilwaukeeWisconsin53226; Department of Cell Biology, Neurobiology and AnatomyMedical College of WisconsinMilwaukeeWisconsin53226
| | - Linda M Reis
- Department of Pediatrics and Children's Research Institute Medical College of Wisconsin Milwaukee Wisconsin 53226
| | - Elena A Sorokina
- Department of Pediatrics and Children's Research Institute Medical College of Wisconsin Milwaukee Wisconsin 53226
| | - Elena V Semina
- Department of Pediatrics and Children's Research InstituteMedical College of WisconsinMilwaukeeWisconsin53226; Department of Cell Biology, Neurobiology and AnatomyMedical College of WisconsinMilwaukeeWisconsin53226
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SIPA1L3 identified by linkage analysis and whole-exome sequencing as a novel gene for autosomal recessive congenital cataract. Eur J Hum Genet 2015; 23:1627-33. [PMID: 25804400 DOI: 10.1038/ejhg.2015.46] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 02/10/2015] [Accepted: 02/11/2015] [Indexed: 12/25/2022] Open
Abstract
Congenital cataract (CC) is one of the most important causes for blindness or visual impairment in infancy. A substantial proportion of isolated CCs has monogenic causes. The disease is genetically heterogeneous, and all Mendelian modes of inheritance have been reported. We mapped a locus for isolated CC on 19p13.1-q13.2 in a distantly consanguineous German family with two sisters affected by dense white cataracts. Whole-exome sequencing identified a homozygous nonsense variant c.4489C>T (p.(R1497*)) in SIPA1L3 (signal-induced proliferation-associated 1 like 3) in both affected children. SIPA1L3 encodes a GTPase-activating protein (GAP), which interacts with small GTPases of the Rap family via its Rap-GAP-domain. The suggested role of Rap GTPases in cell growth, differentiation and organization of the cytoskeleton in the human lens, and lens-enriched expression of the murine ortholog gene Sipa1l3 in embryonic mice indicates that this gene is crucial for early lens development. Our results provide evidence that sequence variants in human SIPA1L3 cause autosomal recessive isolated CC and give new insight into the molecular pathogenesis underlying human cataracts.
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Song Z, Wang L, Liu Y, Xiao W. A novel nonsense mutation in the MIP gene linked to congenital posterior polar cataracts in a Chinese family. PLoS One 2015; 10:e0119296. [PMID: 25803033 PMCID: PMC4372439 DOI: 10.1371/journal.pone.0119296] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 01/12/2015] [Indexed: 11/19/2022] Open
Abstract
Purpose To detect the causative mutation for congenital posterior polar cataracts in a five-generation Chinese family and further explore the potential pathogenesis of this disease. Methods Coding exons, with flanking sequences of five candidate genes, were screened using direct DNA sequencing. The identified mutations were confirmed by restriction fragment length polymorphism (RFLP) analysis. A full-length wild-type or an Y219* mutant aquaporin0 (AQP0) fused with an N-terminal FLAG tag, was transfected into HEK293T cells. For co-localization studies, FLAG-WT-AQP0 and Myc-Y219*-AQP0 constructs were co-transfected. Quantitative real-time RT-PCR, western blotting and immunofluorescence studies were performed to determine protein expression levels and sub-cellular localization, respectively. Results We identified a novel nonsense mutation in MIP (c.657 C>G; p.Y219*) (major intrinsic protein gene) that segregates with congenital posterior polar cataract in a Chinese family. This mutation altered a highly conserved tyrosine to a stop codon (Y219*) within AQP0.When FLAG-WT-AQP0 and FLAG-Y219*-AQP0 expression constructs were singly transfected into HEK 293T cells, mRNA expression showed no significant difference between the wild-type and the mutant, while Y219*-AQP0 protein expression was significantly lower than that of wild-type AQP0. Wild-type AQP0 predominantly localized to the plasma membrane, while the mutated protein was abundant within the cytoplasm of HEK293T cells. However, when FLAG-WT-AQP0 andMyc-MU-AQP0were co-expressed, both proteins showed high fluorescence in the cytoplasm. Conclusions The novel nonsense mutation in the MIP gene (c.657 C>G) identified in a Chinese family may cause posterior polar cataracts. The dominant negative effect of the mutated protein on the wild-type protein interfered with the trafficking of wild-type protein to the cell membrane and both the mutant and wild-type protein were trapped in the cytoplasm. Consequently, both wild-type and mutant protein lost their function as a water channel on the cell membrane, and may result in a cataract phenotype. Our data also expands the spectrum of known MIP mutations.
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Affiliation(s)
- Zixun Song
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
| | - Lianqing Wang
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P. R. China
| | - Yaping Liu
- Department of Medical Genetics, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing 100005, P. R. China
| | - Wei Xiao
- Department of Ophthalmology, Shengjing Hospital of China Medical University, Shenyang, Liaoning, 110004, China
- * E-mail:
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Zhu Y, Yu H, Wang W, Gong X, Yao K. A novel GJA8 mutation (p.V44A) causing autosomal dominant congenital cataract. PLoS One 2014; 9:e115406. [PMID: 25517998 PMCID: PMC4269439 DOI: 10.1371/journal.pone.0115406] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 11/24/2014] [Indexed: 12/16/2022] Open
Abstract
Purpose To examine the mechanism by which a novel connexin 50 (Cx50) mutation, Cx50 V44A, in a Chinese family causes suture-sparing autosomal dominant congenital nuclear cataracts. Methods Family history and clinical data were recorded and direct gene sequencing was used to identify the disease-causing mutation. The Cx50 gene was cloned from a human lens cDNA library. Connexin protein distributions were assessed by fluorescence microscopy. Hemichannel functions were analyzed by dye uptake assay. Formation of functional channels was assessed by dye transfer experiments. Results Direct sequencing of the candidate GJA8 gene revealed a novel c.131T>C transition in exon 2, which cosegregated with the disease in the family and resulted in the substitution of a valine residue with alanine at codon 44 (p. V44A) in the extracellular loop 1 of the Cx50 protein. Both Cx50 and Cx50V44A formed functional gap junctions, as shown by the neurobiotin transfer assay. However, unlike wild-type Cx50, Cx50V44A was unable to form open hemichannels in dye uptake experiments. Conclusion This work identified a unique congenital cataract in the Chinese population, caused by the novel mutation Cx50V44A, and it showed that the V44A mutation specifically impairs the gating of the hemichannels but not the gap junction channels. The dysfunctional hemichannels resulted in the development of human congenital cataracts.
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Affiliation(s)
- Yanan Zhu
- Eye center, 2nd Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Key Laboratory of Ophthalmology of Zhejiang Province, Wenzhou, China
| | - Hao Yu
- Department of Neurobiology, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Wei Wang
- Eye center, 2nd Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Key Laboratory of Ophthalmology of Zhejiang Province, Wenzhou, China
| | - Xiaohua Gong
- School of Optometry and Vision Science Program, University of California, Berkeley, California, United States of America
| | - Ke Yao
- Eye center, 2nd Affiliated Hospital of Medical College, Zhejiang University, Hangzhou, China
- Key Laboratory of Ophthalmology of Zhejiang Province, Wenzhou, China
- * E-mail:
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Mackay DS, Bennett TM, Culican SM, Shiels A. Exome sequencing identifies novel and recurrent mutations in GJA8 and CRYGD associated with inherited cataract. Hum Genomics 2014; 8:19. [PMID: 25403472 PMCID: PMC4240822 DOI: 10.1186/s40246-014-0019-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Accepted: 10/23/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Inherited cataract is a clinically important and genetically heterogeneous cause of visual impairment. Typically, it presents at an early age with or without other ocular/systemic signs and lacks clear phenotype-genotype correlation rendering both clinical classification and molecular diagnosis challenging. Here we have utilized trio-based whole exome sequencing to discover mutations in candidate genes underlying autosomal dominant cataract segregating in three nuclear families. RESULTS In family A, we identified a recurrent heterozygous mutation in exon-2 of the gene encoding γD-crystallin (CRYGD; c.70C > A, p.Pro24Thr) that co-segregated with 'coralliform' lens opacities. Families B and C were found to harbor different novel variants in exon-2 of the gene coding for gap-junction protein α8 (GJA8; c.20T > C, p.Leu7Pro and c.293A > C, p.His98Pro). Each novel variant co-segregated with disease and was predicted in silico to have damaging effects on protein function. CONCLUSIONS Exome sequencing facilitates concurrent mutation-profiling of the burgeoning list of candidate genes for inherited cataract, and the results can provide enhanced clinical diagnosis and genetic counseling for affected families.
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Affiliation(s)
- Donna S Mackay
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA.
| | - Thomas M Bennett
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA.
| | - Susan M Culican
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA.
| | - Alan Shiels
- Department of Ophthalmology and Visual Sciences, Washington University School of Medicine, 660 S. Euclid Ave., Box 8096, St. Louis, Missouri, 63110, USA.
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Reis LM, Tyler RC, Semina EV. Identification of a novel C-terminal extension mutation in EPHA2 in a family affected with congenital cataract. Mol Vis 2014; 20:836-42. [PMID: 24940039 PMCID: PMC4057250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2013] [Accepted: 06/11/2013] [Indexed: 11/10/2022] Open
Abstract
PURPOSE Congenital cataracts occur in 3-4 per 10,000 live births and account for 5% to 20% of pediatric blindness worldwide. With more than 37 genes known to be associated with isolated congenital cataract, whole exome sequencing (WES) was recently introduced as an efficient method for screening all known factors. METHODS Whole exome analysis in two members of a four-generation pedigree affected with dominant congenital cataract and glaucoma was performed by WES; co-segregation analysis of identified variants in all pedigree members was completed by Sanger sequencing. RESULTS Analysis of the WES data identified a novel pathogenic variant in EPHA2, c.2925dupC, p.(Ile976Hisfs*37), that demonstrated complete cosegregation with the phenotype in the pedigree. The mutation occurs in the final amino acid before the stop codon of the normal EPHA2 protein and is predicted to produce a mutant protein with an erroneous C-terminal extension of 35 amino acids. Nine other families have been previously reported with dominant congenital/juvenile cataracts and mutations in EPHA2. Two additional likely loss-of-function variants in genes known to cause dominant congenital cataract were considered and excluded based on control data and cosegregation analysis: a nonsense variant in CYRBB3, c.547G>T, p.(Glu183*), and a splicing variant in CRYBA2, c.446+1G>A. CONCLUSIONS Identification of a novel pathogenic EPHA2 allele further implicates this gene in congenital cataract. This is only the second EPHA2 mutation that specifically affects the most C-terminal PSD95/Dlg/ZO1 (PDZ)-binding motif and the third pathogenic allele associated with an erroneous C-terminal extension beyond the normal stop codon.
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Affiliation(s)
- Linda M. Reis
- Department of Pediatrics and Children’s Research Institute, Medical College of Wisconsin, Milwaukee, WI
| | - Rebecca C. Tyler
- Department of Pediatrics and Children’s Research Institute, Medical College of Wisconsin, Milwaukee, WI
| | - Elena V. Semina
- Department of Pediatrics and Children’s Research Institute, Medical College of Wisconsin, Milwaukee, WI,Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI
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Chhetri J, Jacobson G, Gueven N. Zebrafish--on the move towards ophthalmological research. Eye (Lond) 2014; 28:367-80. [PMID: 24503724 PMCID: PMC3983641 DOI: 10.1038/eye.2014.19] [Citation(s) in RCA: 105] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2013] [Accepted: 01/15/2014] [Indexed: 12/15/2022] Open
Abstract
Millions of people are affected by visual impairment and blindness globally, and the prevalence of vision loss is likely to increase as we are living longer. However, many ocular diseases remain poorly controlled due to lack of proper understanding of the pathogenesis and the corresponding lack of effective therapies. Consequently, there is a major need for animal models that closely mirror the human eye pathology and at the same time allow higher-throughput drug screening approaches. In this context, zebrafish as an animal model organism not only address these needs but can in many respects reflect the human situation better than the current rodent models. Over the past decade, zebrafish have become an established model to study a variety of human diseases and are more recently becoming a valuable tool for the study of human ophthalmological disorders. Many human ocular diseases such as cataract, glaucoma, diabetic retinopathy, and age-related macular degeneration have already been modelled in zebrafish. In addition, zebrafish have become an attractive model for pre-clinical drug toxicity testing and are now increasingly used by scientists worldwide for the discovery of novel treatment approaches. This review presents the advantages and uses of zebrafish for ophthalmological research.
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Affiliation(s)
- J Chhetri
- School of Pharmacy, University of Tasmania, Hobart, TAS, Australia
| | - G Jacobson
- School of Pharmacy, University of Tasmania, Hobart, TAS, Australia
| | - N Gueven
- School of Pharmacy, University of Tasmania, Hobart, TAS, Australia
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Worthey EA. Analysis and annotation of whole-genome or whole-exome sequencing-derived variants for clinical diagnosis. CURRENT PROTOCOLS IN HUMAN GENETICS 2013; 79:9.24.1-9.24.24. [PMID: 24510652 DOI: 10.1002/0471142905.hg0924s79] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Over the last several years, next-generation sequencing (NGS) has transformed genomic research through substantial advances in technology and reduction in the cost of sequencing, and also in the systems required for analysis of these large volumes of data. This technology is now being used as a standard molecular diagnostic test under particular circumstances in some clinical settings. The advances in sequencing have come so rapidly that the major bottleneck in identification of causal variants is no longer the sequencing but rather the analysis and interpretation. Interpretation of genetic findings in a clinical setting is scarcely a new challenge, but the task is increasingly complex in clinical genome-wide sequencing given the dramatic increase in dataset size and complexity. This increase requires the development of novel or repositioned analysis tools, methodologies, and processes. This unit provides an overview of these items. Specific challenges related to implementation in a clinical setting are discussed.
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Affiliation(s)
- Elizabeth A Worthey
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, Wisconsin.,The Human and Molecular Genetics Center, Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Computer Science, University of Wisconsin, Milwaukee, Wisconsin
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