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Yu QC, Geng A, Preusch CB, Chen Y, Peng G, Xu Y, Jia Y, Miao Y, Xue H, Gao D, Bao L, Pan W, Chen J, Garcia KC, Cheung TH, Zeng YA. Activation of Wnt/β-catenin signaling by Zeb1 in endothelial progenitors induces vascular quiescence entry. Cell Rep 2022; 41:111694. [DOI: 10.1016/j.celrep.2022.111694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 08/05/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022] Open
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Kannabiran C, Chaurasia S, Ramappa M, Mootha VV. Update on the genetics of corneal endothelial dystrophies. Indian J Ophthalmol 2022; 70:2239-2248. [PMID: 35791103 PMCID: PMC9426112 DOI: 10.4103/ijo.ijo_992_22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Corneal endothelial dystrophies are a heterogeneous group of diseases with different modes of inheritance and genetic basis for each dystrophy. The genes associated with these diseases encode transcription factors, structural components of the stroma and Descemet membrane, cell transport proteins, and others. Congenital hereditary endothelial dystrophy (CHED) is associated with mutations in two genes, OVOL2 and SLC4A11, for dominant and recessive forms of CHED, respectively. Mutations in three genes are known to cause posterior polymorphous corneal dystrophy (PPCD). They are OVOL2 (PPCD1), ZEB1 (PPCD3), and GRHL1 (PPCD4). The PPCD2 locus involving the collagen gene COL8A2 on chromosome 1 is disputed due to insufficient evidence. Mutations in the COL8A2 gene are associated with early-onset Fuchs’ endothelial corneal dystrophy (FECD). Several genes have been associated with the more common, late-onset FECD. Alterations in each of these genes occur in a fraction of patients, and the most prevalent genetic alteration in FECD patients across the world is a triplet repeat expansion in the TCF4 gene. Knowledge of the genetics of corneal endothelial dystrophies has considerably advanced within the last decade and has contributed to better diagnosis of these dystrophies as well as opened up the possibility of novel therapeutic approaches based on the molecular mechanisms involved. The functions of genes identified to date provide insights into the pathogenic mechanisms involved in each disorder.
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Affiliation(s)
- Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, Prof Brien Holden Eye Research Centre, L.V. Prasad Eye Institute, Hyderabad, Telangana, India
| | - Sunita Chaurasia
- Centre for Rare Eye Diseases and Ocular Genetics; The Cornea Institute; Jasti V Ramanamma Children's Eye Care Center, L.V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India
| | - Muralidhar Ramappa
- Centre for Rare Eye Diseases and Ocular Genetics; The Cornea Institute; Jasti V Ramanamma Children's Eye Care Center, L.V. Prasad Eye Institute, Kallam Anji Reddy Campus, Hyderabad, Telangana, India
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c.-61G>A in OVOL2 is a Pathogenic 5' Untranslated Region Variant Causing Posterior Polymorphous Corneal Dystrophy 1. Cornea 2021; 41:89-94. [PMID: 34469340 DOI: 10.1097/ico.0000000000002843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 06/07/2021] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of this study was to investigate the clinical and genetic features of a man and his daughter with posterior polymorphous corneal dystrophy (PPCD), referred to our clinic for Descemet membrane endothelial keratoplasty. No other known relatives were affected. METHODS Ophthalmic examination and histology, including electron microscopy, were performed. Genetic testing was conducted by means of whole exome sequencing, and variant analysis was achieved by using an internal in silico pipeline. Molecular tests included a dual-luciferase assay. RESULTS Slowly progressive blurred vision was reported from childhood by the daughter. The father's symptoms started at age 55. Best-corrected visual acuity was reduced in both patients (0.2-0.4). Slit-lamp examination in both patients revealed bilateral corneal clouding with gray endothelial lesions; other family members had no ophthalmological signs. Descemet membrane endothelial keratoplasty was performed uneventfully in both patients. Histology showed thickened Descemet membrane and abnormal endothelium resembling epithelial-like cells. Both patients carried the OVOL2 5' untranslated region NM_021220.4.c.-61G>A variant in the heterozygous state. This change was associated with increased promoter activity and was not present in the unaffected members of the family. CONCLUSIONS The 5' untranslated region mutation c.-61G>A in OVOL2 has been previously found in 1 individual with PPCD1 and reported as a variant of unknown significance because of insufficient evidence supporting its pathogenicity. Identification of the second family with 2 individuals affected by PPCD1 carrying this change, together with functional data, provides further proofs that it is disease-causing.
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Alterations in GRHL2-OVOL2-ZEB1 axis and aberrant activation of Wnt signaling lead to altered gene transcription in posterior polymorphous corneal dystrophy. Exp Eye Res 2019; 188:107696. [DOI: 10.1016/j.exer.2019.107696] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/02/2019] [Accepted: 06/11/2019] [Indexed: 12/11/2022]
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Kim Y, You HJ, Park SH, Kim MS, Chae H, Park J, Jekarl DW, Kim J, Kwon A, Choi H, Kim Y, Paek AR, Lee A, Kim JM, Park SY, Kim Y, Joo K, Jung J, Chung SH, Mok JW, Kim M. A Mutation in ZNF143 as a Novel Candidate Gene for Endothelial Corneal Dystrophy. J Clin Med 2019; 8:jcm8081174. [PMID: 31390831 PMCID: PMC6723187 DOI: 10.3390/jcm8081174] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 08/02/2019] [Accepted: 08/04/2019] [Indexed: 02/06/2023] Open
Abstract
Corneal dystrophies (CDs) are a diverse group of inherited disorders with a heterogeneous genetic background. Here, we report the identification of a novel ZNF143 heterozygous missense mutation in three individuals of the same family with clinical and pathological features that are consistent with endothelial CD. Ophthalmologic examination revealed diffuse corneal clouding and edema with decreased endothelial cell density. Pathological findings showed increased corneal thickness due to edema of basal epithelial cells and stroma, and abnormal metaplastic endothelium with stratified epithelium-like changes. Patients’ metaplastic corneal endothelial cells expressed predominantly cytokerain 7, cytokeratin 19, and E-cadherin. Although Sanger sequencing did not detect any mutation associated with endothelial CDs, whole exome sequencing identified the ZNF143 c.937G>C p.(Asp313His) mutation as a candidate gene for our patients’ endothelial CD. In-vitro functional studies demonstrated that mutant ZNF143 promoted the mesenchymal-to-epithelial transition; it upregulated the expression of genes associated with epithelialization in human corneal endothelial cells. Additionally, proinflammatory cytokine responsive genes were significantly enriched after mutant ZNF143 transfection, which may contribute to the severe phenotype of the three patients. These findings link a mutation in ZNF143 with endothelial CD for the first time.
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Affiliation(s)
- Yonggoo Kim
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Hye Jin You
- Cancer Cell and Molecular Biology Branch, Division of Cancer Biology, National Cancer Center, Gyeonggi-do 10408, Korea
| | - Shin Hae Park
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Man Soo Kim
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Hyojin Chae
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Joonhong Park
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Dong Wook Jekarl
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Jiyeon Kim
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Ahlm Kwon
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Hayoung Choi
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - Yeojae Kim
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | - A Rome Paek
- Cancer Cell and Molecular Biology Branch, Division of Cancer Biology, National Cancer Center, Gyeonggi-do 10408, Korea
| | - Ahwon Lee
- Department of Hospital Pathology, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
| | | | - Seon Young Park
- Department of Life Systems, Sookmyung Women's University, Seoul 04312, Korea
| | - Yonghwan Kim
- Department of Life Systems, Sookmyung Women's University, Seoul 04312, Korea
| | - Keehyoung Joo
- Center for in Silico Protein Science, Korea Institute for Advanced Study, Seoul 02455, Korea
- Center for Advanced Computation, Korea Institute for Advanced Study, Seoul 02455, Korea
- Center for Advanced Computation, Korea Institute for Advanced Study, Seoul 02455, Korea
| | | | - So-Hyang Chung
- Department of Ophthalmology and Visual Science, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea
- Catholic Institutes of Visual Science, The Catholic University of Korea, Seoul 06591, Korea
| | - Jee Won Mok
- Catholic Institutes of Visual Science, The Catholic University of Korea, Seoul 06591, Korea
| | - Myungshin Kim
- Department of Laboratory Medicine, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
- Catholic Genetic Laboratory Center, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul 06591, Korea.
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Davidson AE, Hafford-Tear NJ, Dudakova L, Sadan AN, Pontikos N, Hardcastle AJ, Tuft SJ, Liskova P. CUGC for posterior polymorphous corneal dystrophy (PPCD). Eur J Hum Genet 2019; 28:126-131. [PMID: 31201376 DOI: 10.1038/s41431-019-0448-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/23/2019] [Accepted: 05/31/2019] [Indexed: 11/09/2022] Open
Abstract
Name of the disease (synonyms) CUGC for posterior polymorphous corneal dystrophy (PPCD).OMIM# of the disease 122000; 609141; 618031.Name of the analysed genes or DNA/chromosome segments OVOL2 (PPCD1); ZEB1 (PPCD3); GRHL2 (PPCD4).OMIM# of the gene(s) 616441; 189909; 608576. Review of the analytical and clinical validity as well as of the clinical utility of DNA-based testing for variants in theOVOL2, ZEB1andGRHL2gene(s) in a diagnostic setting, predictive and parental settings and for risk assesment in relatives.
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Affiliation(s)
| | | | - Lubica Dudakova
- First Faculty of Medicine, Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08, Prague 2, Czech Republic
| | | | | | | | - Stephen J Tuft
- UCL Institute of Ophthalmology, London, EC1V 9EL, UK.,Moorfields Eye Hospital, London, EC1V 2PD, UK
| | - Petra Liskova
- First Faculty of Medicine, Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08, Prague 2, Czech Republic
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Litke AM, Samuelson S, Delaney KR, Sauvé Y, Chow RL. Investigating the Pathogenicity of VSX1 Missense Mutations and Their Association With Corneal Disease. Invest Ophthalmol Vis Sci 2019; 59:5824-5835. [PMID: 30535423 DOI: 10.1167/iovs.18-25490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Despite numerous studies associating Visual System Homeobox 1 (VSX1), with posterior polymorphous corneal dystrophy and keratoconus, its role in these diseases is unclear. Here we examine the pathogenicity of VSX1 missense mutations in vitro and in a mouse genetic model. Methods Vsx1 transcriptional repressor activity, protein stability, and subcellular localization activity, was examined using luciferase reporter-based assays, western blotting and immunolabeling, respectively, in transfected human embryonic kidney 293T cells. A genetic model for VSX1 p.P247R was generated to investigate pathogenicity of the mutation, in vivo. A wholemount confocal imaging approach on unfixed intact eyes was developed to examine corneal morphology, curvature, and thickness. Immunolabeling and electroretinography was used to examine retinal phenotype. Results A mutation corresponding to human VSX1 p.P247R led to enhanced transcriptional repressor activity, in vitro. A mouse model for VSX1 p.P247R did not have any observable corneal defect, but did exhibit an abnormal electroretinogram response characterized by a more prominent ON as opposed to OFF panretinal responsiveness. In vitro analysis of additional VSX1 missense mutations showed that they either enhanced repressor activity or did not alter activity. Conclusions Our results indicate that although VSX1 sequence variants can alter transcriptional activity, in the context of a mouse genetic model, at least one of these changes does not lead to corneal abnormalities. While we cannot exclude a role for VSX1 as a risk factor for corneal disease, on its own, it does not appear to play a major causative role.
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Affiliation(s)
| | - Sarah Samuelson
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Kerry R Delaney
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Yves Sauvé
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Robert L Chow
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
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Case Report: Iridocorneal Endothelial Syndrome Progression Documented by Anterior Segment Optical Coherence Tomography. Optom Vis Sci 2019; 96:309-313. [PMID: 30907858 DOI: 10.1097/opx.0000000000001358] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
SIGNIFICANCE Iridocorneal endothelial (ICE) syndrome is characterized by a difficult-to-see membrane of ectopic corneal endothelial cells, called an ICE membrane. This report demonstrates that ICE membranes are detectable by anterior segment optical coherence tomography (AS-OCT) and highlights the benefits of using AS-OCT in ICE syndrome. PURPOSE A case of ICE syndrome is reported to highlight the utility of AS-OCT in the characterization and diagnosis of the disease. CASE REPORT A 65-year-old African American man was diagnosed as having the Chandler variant of ICE syndrome of the left eye. He was treated topically for corneal edema. Anterior segment optical coherence tomography and anterior segment photography were used to aid in the diagnosis and document an ICE membrane and multiple peripheral anterior synechiae. Further examinations chronicled the progression of a peripheral anterior synechia. At first, only iridocorneal touch (sparing the trabecular meshwork) was present, but later, full apposition to the trabecular meshwork developed. The patient was diagnosed as having pre-perimetric glaucoma in the left eye and is being treated topically to reduce his intraocular pressure. The right eye remains unremarkable. CONCLUSIONS Anterior segment optical coherence tomography can support the diagnosis of ICE syndrome by visualizing ICE membranes and differentiating between true peripheral anterior synechiae and iridocorneal touch that does not block the trabecular meshwork. Chronicling ICE membranes longitudinally with AS-OCT will enhance understanding of disease progression. By correlating membranes features (such as location and extent) and patient outcomes, AS-OCT-based ICE membrane classifications can be developed to improve the management and prognosis of ICE syndrome.
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9
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Loukovitis E, Sfakianakis K, Syrmakesi P, Tsotridou E, Orfanidou M, Bakaloudi DR, Stoila M, Kozei A, Koronis S, Zachariadis Z, Tranos P, Kozeis N, Balidis M, Gatzioufas Z, Fiska A, Anogeianakis G. Genetic Aspects of Keratoconus: A Literature Review Exploring Potential Genetic Contributions and Possible Genetic Relationships with Comorbidities. Ophthalmol Ther 2018; 7:263-292. [PMID: 30191404 PMCID: PMC6258591 DOI: 10.1007/s40123-018-0144-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Indexed: 01/24/2023] Open
Abstract
Introduction Keratoconus (KC) is a complex, genetically heterogeneous, multifactorial degenerative disorder that is accompanied by corneal ectasia which usually progresses asymmetrically. With an incidence of approximately 1 per 2000 and 2 cases per 100,000 population presenting annually, KC follows an autosomal recessive or dominant pattern of inheritance and is, apparently, associated with genes that interact with environmental, genetic, and/or other factors. This is an important consideration in refractive surgery in the case of familial KC, given the association of KC with other genetic disorders and the imbalance between dizygotic twins. The present review attempts to identify the genetic loci contributing to the different KC clinical presentations and relate them to the common genetically determined comorbidities associated with KC. Methods The PubMed, MEDLINE, Google Scholar, and GeneCards databases were screened for KC-related articles published in English between January 2006 and November 2017. Keyword combinations of “keratoconus,” “risk factor(s),” “genetics,” “genes,” “genetic association(s),” and “cornea” were used. In total, 217 articles were retrieved and analyzed, with greater weight placed on the more recent literature. Further bibliographic research based on the 217 articles revealed another 124 relevant articles that were included in this review. Using the reviewed literature, an attempt was made to correlate genes and genetic risk factors with KC characteristics and genetically related comorbidities associated with KC based on genome-wide association studies, family-based linkage analysis, and candidate-gene approaches. Results An association matrix between known KC-related genes and KC symptoms and/or clinical signs together with an association matrix between identified KC genes and genetically related KC comorbidities/syndromes were constructed. Conclusion Twenty-four genes were identified as potential contributors to KC and 49 KC-related comorbidities/syndromes were found. More than 85% of the known KC-related genes are involved in glaucoma, Down syndrome, connective tissue disorders, endothelial dystrophy, posterior polymorphous corneal dystrophy, and cataract.
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Affiliation(s)
| | - Konstantinos Sfakianakis
- Division of Surgical Anatomy, Laboratory of Anatomy, Medical School, Democritus University of Thrace, University Campus, Alexandroupolis, Greece
| | - Panagiota Syrmakesi
- AHEPA University Hospital, Thessaloníki, Greece.,Ophthalmica Eye Institute, Thessaloníki, Greece
| | - Eleni Tsotridou
- Ophthalmica Eye Institute, Thessaloníki, Greece.,Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Myrsini Orfanidou
- Ophthalmica Eye Institute, Thessaloníki, Greece.,Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Dimitra Rafailia Bakaloudi
- Ophthalmica Eye Institute, Thessaloníki, Greece.,Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Maria Stoila
- Ophthalmica Eye Institute, Thessaloníki, Greece.,Faculty of Medicine, Aristotle University of Thessaloniki, Thessaloníki, Greece
| | - Athina Kozei
- Ophthalmica Eye Institute, Thessaloníki, Greece.,School of Pharmacology, University of Nicosia, Makedonitissis, Nicosia, Cyprus
| | | | | | | | | | | | - Zisis Gatzioufas
- Department of Ophthalmology, Cornea, Cataract and Refractive Surgery, University Hospital Basel, Basel, Switzerland
| | - Aliki Fiska
- Laboratory of Anatomy, Medical School, Democritus University of Thrace, University Campus, Alexandroupolis, Greece
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Lucas SEM, Zhou T, Blackburn NB, Mills RA, Ellis J, Leo P, Souzeau E, Ridge B, Charlesworth JC, Lindsay R, Craig JE, Burdon KP. Rare, potentially pathogenic variants in 21 keratoconus candidate genes are not enriched in cases in a large Australian cohort of European descent. PLoS One 2018; 13:e0199178. [PMID: 29924831 PMCID: PMC6010250 DOI: 10.1371/journal.pone.0199178] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 06/01/2018] [Indexed: 12/30/2022] Open
Abstract
Many genes have been suggested as candidate genes for keratoconus based on their function, their proximity to associated polymorphisms or due to the identification of putative causative variants within the gene. However, very few of these genes have been assessed for rare variation in keratoconus more broadly. In contrast, VSX1 and SOD1 have been widely assessed, however, the vast majority of studies have been small and the findings conflicting. In a cohort of Australians of European descent, consisting of 385 keratoconus cases and 396 controls, we screened 21 keratoconus candidate genes: BANP, CAST, COL4A3, COL4A4, COL5A1, FOXO1, FNDC3B, HGF, IL1A, IL1B, ILRN, IMMP2L, MPDZ, NFIB, RAB3GAP1, RAD51, RXRA, SLC4A11, SOD1, TF and VSX1. The candidate genes were sequenced in these individuals by either whole exome sequencing or targeted gene sequencing. Variants were filtered to identify rare (minor allele frequency <1%), potentially pathogenic variants. A total of 164 such variants were identified across the two groups with no variants fulfilling these criteria in cases in IL1RN, BANP, IL1B, RAD51 or SOD1. The frequency of variants was compared between cases and controls using chi-square or Fishers' Exact tests for each gene with at least one rare potentially pathogenic variant identified in the case cohort. The number of rare potentially pathogenic variants per gene ranged from three (RXRA) to 102 (MPDZ), however for all genes, there was no difference in the frequency between the cases and controls. We conclude that rare potentially pathogenic variation in the 21 candidate genes assessed do not play a major role in keratoconus susceptibility and pathogenesis.
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Affiliation(s)
- Sionne E. M. Lucas
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Tiger Zhou
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Nicholas B. Blackburn
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
- South Texas Diabetes and Obesity Institute, Department of Human Genetics, School of Medicine, University of Texas Rio Grande Valley, Brownsville, Texas, United States of America
| | - Richard A. Mills
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Jonathan Ellis
- Queensland University of Technology and Translational Research Institute, Princess Alexandra Hospital, Brisbane, Queensland, Australia
| | - Paul Leo
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Emmanuelle Souzeau
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Bronwyn Ridge
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Jac C. Charlesworth
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
| | - Richard Lindsay
- Richard Lindsay and Associates, East Melbourne, Victoria, Australia
| | - Jamie E. Craig
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Kathryn P. Burdon
- Menzies Institute for Medical Research, University of Tasmania, Hobart, Tasmania, Australia
- * E-mail:
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Siebelmann S, Scholz P, Sonnenschein S, Bachmann B, Matthaei M, Cursiefen C, Heindl LM. Anterior segment optical coherence tomography for the diagnosis of corneal dystrophies according to the IC3D classification. Surv Ophthalmol 2018; 63:365-380. [DOI: 10.1016/j.survophthal.2017.08.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/31/2017] [Accepted: 08/03/2017] [Indexed: 11/30/2022]
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12
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Shen AL, Moran SM, Glover EA, Teixeira LB, Bradfield CA. Retinal pathology in the PPCD1 mouse. PLoS One 2017; 12:e0185094. [PMID: 28981549 PMCID: PMC5628829 DOI: 10.1371/journal.pone.0185094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 09/06/2017] [Indexed: 12/30/2022] Open
Abstract
Retinal phenotypes of the PPCD1 mouse, a mouse model of posterior polymorphous corneal dystrophy, have been characterized. PPCD1 mice on the DBA/2J background (D2.Ppcd1) have previously been reported to develop an enlarged anterior chamber due to epithelialization and proliferation of the corneal endothelium and subsequent blockage of the iridocorneal angle. Results presented here show that D2.Ppcd1 mice develop increased intraocular pressure (IOP), with measurements at three months of age revealing significant increases in IOP. Significant retinal ganglion cell layer cell loss is observed at five months of age. D2.Ppcd1 animals also exhibit marked degeneration of the outer nuclear layer in association with hyperplasia of the retinal pigment epithelium. Evidence of retinal detachment is present as early as three weeks of age. By 3.5 months of age, focal areas of outer nuclear layer loss are observed. Although the GpnmbR150X mutation leads to increased IOP and glaucoma in DBA/2J mice, development of anterior segment and retinal defects in D2.Ppcd1 animals does not depend upon presence of the GpnmbR150X mutation.
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Affiliation(s)
- Anna L. Shen
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (CAB); (ALS)
| | - Susan M. Moran
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Edward A. Glover
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Leandro B. Teixeira
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Christopher A. Bradfield
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (CAB); (ALS)
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Abstract
PURPOSE To describe clinical features in children diagnosed with posterior polymorphous corneal dystrophy (PPCD) in their first or second decade of life. METHODS A retrospective study was performed with the medical records of seven unrelated Korean pediatric patients who were diagnosed with PPCD and were followed up for a minimum of 3 years. Thorough ocular examinations were performed, including best-corrected visual acuity, intraocular pressure, refractive and keratometric measurements, slit-lamp biomicroscopy, and specular microscopy at all visits. RESULTS Slit-lamp examinations revealed vesicular lesions in one patient and horizontally parallel band-like endothelial lesions in six patients. Unilateral corneal involvement was displayed in 4 patients, yielding 10 eyes with deep corneal features characteristic of PPCD. Other corneal, iris, or fundus pathologic findings were not detected in all cases. Among four children who were examined in their visual development (approximately under 8 years of age), two cases demonstrated unilateral amblyopia at initial examination and exhibited improved visual acuity after refractive correction and occlusion therapy. Astigmatism more than 1.5D, which is generally considered amblyogenic, was found in 8 among 10 PPCD-affected eyes. A final visual acuity of more than 20/32 was achieved with appropriate refractive correction in all PPCD-affected eyes. There was a negative correlation between the corneal astigmatism and the mean endothelial cell density (ECD) (r = -0.655, P = .011). Initial specular microscopic examinations revealed reduced ECD (1733.0 ± 543.9 cells/mm) composed of enlarged cells (average cell area, 624.8 ± 182.1 μm/cell) in PPCD-affected eyes, compared with those in PPCD-unaffected eyes from our study subjects (P < .001 and P = .005, respectively). A statistically significant percent loss in ECD from initial to 3 years was noted in the PPCD-affected eyes (P = .03). CONCLUSIONS The awareness and treatment of refractive error are important, especially in children with early-onset PPCD during the reversible period of amblyopia. Long-term monitoring of corneal endothelium is required in pediatric patients with early-onset PPCD based on a significant endothelial loss over 3 years in PPCD-affected eyes.
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Moussa S, Grabner G, Ruckhofer J, Dietrich M, Reitsamer H. Genetics in Keratoconus - What is New? Open Ophthalmol J 2017; 11:201-210. [PMID: 28932336 PMCID: PMC5585456 DOI: 10.2174/1874364101711010201] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2017] [Revised: 04/01/2017] [Accepted: 06/14/2017] [Indexed: 11/22/2022] Open
Abstract
Background: Keratoconus is characterized as a bilateral, progressive, non-inflammatory thinning of the cornea resulting in blurred vision due to irregular astigmatism. Keratoconus has a multifactorial etiology, with multiple genetic and environmental components contributing to the disease pathophysiology. Several genomic loci and genes have been identified that highlight the complex molecular etiology of this disease. Conclusion: The review focuses on current knowledge of these genetic risk factors associated with keratoconus.
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Affiliation(s)
- Sarah Moussa
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Günther Grabner
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Josef Ruckhofer
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Marie Dietrich
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
| | - Herbert Reitsamer
- Paracelsus Medical University Salzburg, Department of Ophthalmology and Optometry, Müllner Hauptstr. 48, 5020 Salzburg, Austria
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Mas Tur V, MacGregor C, Jayaswal R, O'Brart D, Maycock N. A review of keratoconus: Diagnosis, pathophysiology, and genetics. Surv Ophthalmol 2017; 62:770-783. [PMID: 28688894 DOI: 10.1016/j.survophthal.2017.06.009] [Citation(s) in RCA: 266] [Impact Index Per Article: 38.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 06/26/2017] [Accepted: 06/29/2017] [Indexed: 12/11/2022]
Abstract
We discuss new approaches to the early detection of keratoconus and recent investigations regarding the nature of its pathophysiology. We review the current evidence for its complex genetics and evaluate the presently identified genes/loci and potential candidate gene/loci. In addition, we highlight current research methodologies that may be used to further elucidate the pathogenesis of keratoconus.
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Affiliation(s)
- Veronica Mas Tur
- Eye Department, Queen Alexandra Hospital, Portsmouth, Hants, United Kingdom
| | - Cheryl MacGregor
- Eye Department, Queen Alexandra Hospital, Portsmouth, Hants, United Kingdom
| | - Rakesh Jayaswal
- Eye Department, Queen Alexandra Hospital, Portsmouth, Hants, United Kingdom
| | - David O'Brart
- Department of Ophthalmology, St Thomas' Hospital, London, United Kingdom
| | - Nicholas Maycock
- Department of Ophthalmology, St Thomas' Hospital, London, United Kingdom.
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State of the Art and Beyond: Anterior Segment Diagnostics Genetic Diagnostics in Corneal Disease. Int Ophthalmol Clin 2017; 57:13-26. [PMID: 28590278 DOI: 10.1097/iio.0000000000000178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Chung DD, Frausto RF, Cervantes AE, Gee KM, Zakharevich M, Hanser EM, Stone EM, Heon E, Aldave AJ. Confirmation of the OVOL2 Promoter Mutation c.-307T>C in Posterior Polymorphous Corneal Dystrophy 1. PLoS One 2017; 12:e0169215. [PMID: 28046031 PMCID: PMC5207508 DOI: 10.1371/journal.pone.0169215] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 12/13/2016] [Indexed: 01/28/2023] Open
Abstract
Purpose To identify the genetic basis of posterior polymorphous corneal dystrophy (PPCD) in families mapped to the PPCD1 locus and in affected individuals without ZEB1 coding region mutations. Methods The promoter, 5’ UTR, and coding regions of OVOL2 was screened in the PPCD family in which linkage analysis established the PPCD1 locus and in 26 PPCD probands who did not harbor a ZEB1 mutation. Copy number variation (CNV) analysis in the PPCD1 and PPCD3 intervals was performed on DNA samples from eight probands using aCGH. Luciferase reporter assays were performed in human corneal endothelial cells to determine the impact of the identified potentially pathogenic variants on OVOL2 promoter activity. Results OVOL2 mutation analysis in the first PPCD1-linked family demonstrated segregation of the c.-307T>C variant with the affected phenotype. In the other 26 probands screened, one heterozygous coding region variant and five promoter region heterozygous variants were identified, though none are likely pathogenic based on allele frequency. Array CGH in the PPCD1 and PPCD3 loci excluded the presence of CNV involving either OVOL2 or ZEB1, respectively. The c.-307T>C variant demonstrated increased promoter activity in corneal endothelial cells when compared to the wild-type sequence as has been demonstrated previously in another cell type. Conclusions Previously identified as the cause of PPCD1, the OVOL2 promoter variant c.-307T>C was herein identified in the original family that established the PPCD1 locus. However, the failure to identify presumed pathogenic coding or non-coding OVOL2 or ZEB1 variants, or CNV involving the PPCD1 and PPCD3 loci in 26 other PPCD probands suggests that other genetic loci may be involved in the pathogenesis of PPCD.
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Affiliation(s)
- Doug D. Chung
- Stein Eye Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Ricardo F. Frausto
- Stein Eye Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Aleck E. Cervantes
- Stein Eye Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Katherine M. Gee
- Stein Eye Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Marina Zakharevich
- Stein Eye Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Evelyn M. Hanser
- Stein Eye Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Edwin M. Stone
- Department of Ophthalmology, University of Iowa Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Elise Heon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Anthony J. Aldave
- Stein Eye Institute, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
- * E-mail:
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Clinical characterization of posterior polymorphous corneal dystrophy in patients of Indian ethnicity. Int Ophthalmol 2016; 37:945-952. [PMID: 27658681 DOI: 10.1007/s10792-016-0360-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 09/18/2016] [Indexed: 10/21/2022]
Abstract
PURPOSE To characterize the clinical presentation of posterior polymorphous corneal dystrophy (PPCD) in eyes of Indian ethnicity. DESIGN Retrospective cohort study from January 1995 to December 2015. PARTICIPANTS Patients with the diagnosis of posterior polymorphous corneal dystrophy. METHODS Medical records of the patients were reviewed for clinical presentation. Histology of corneal specimens of those that underwent keratoplasty was assessed. MAIN OUTCOME MEASURES Descriptive analysis of clinical condition. RESULTS Mean age at first evaluation was 32.5 years (range 1-73 years), male:female = 35:18. Majority (44/53; 83 %) of the patients had bilateral involvement. 5/9 (44 %) patients with unilateral presentation were amblyopic in the affected eye. The clinical features documented were vesicles in 94 eyes, band-like pattern in 32 eyes, edema of varying degree in 23 eyes (12 patients, 1 patient was one eyed), and anterior segment changes in 1 eye. 8/45 (17 %) eyes had a regular astigmatism with steep axis >47 D (range 47.2-56.2 D). 16 eyes of 12 patients who had clinically evident corneal edema underwent keratoplasty. Mean age at keratoplasty was 58 years (range 1-73 years). 8 patients had penetrating keratoplasty (PK) and 8 had Descemet stripping endothelial keratoplasty (DSEK). Mean follow-up after keratoplasty was 4.2 years (1 month to 13 years). Except one, all grafts remained clear till the last follow-up. In all specimens, the Descemet membrane was grossly thickened. CONCLUSIONS In our study, 12/53 (22.6 %) patients required keratoplasty for visually significant corneal edema. Except one, all were older adults. The patients who needed keratoplasty were bilaterally afflicted and had visually significant cornea edema in both eyes. With a mean follow-up duration of 4.2 years after keratoplasty, no recurrences were noted.
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Chung DWD, Frausto RF, Chiu S, Lin BR, Aldave AJ. Investigating the Molecular Basis of PPCD3: Characterization of ZEB1 Regulation of COL4A3 Expression. Invest Ophthalmol Vis Sci 2016; 57:4136-43. [PMID: 27537263 PMCID: PMC4991021 DOI: 10.1167/iovs.16-19533] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Accepted: 06/06/2016] [Indexed: 12/13/2022] Open
Abstract
PURPOSE To investigate the role of the zinc finger e-box binding homeobox 1 (ZEB1) transcription factor in posterior polymorphous corneal dystrophy 3 by demonstrating its ability to regulate type IV collagen gene transcription via binding to putative E2 box motifs. METHODS Putative E2 box motifs were identified by in silico analysis within the promoter region of collagen, type IV, alpha3 (COL4A3) and collagen, type IV, alpha4 (COL4A4). To test the ability of ZEB1 to bind to each identified E2 box, electrophoretic mobility shift assays were performed by incubating ZEB1-enriched nuclear extracts with DIG-labeled probes containing one of each of the identified E2 box motifs. Dual-luciferase reporter assays were performed to test the effects of ZEB1 on the luciferase activity of COL4A3 and cadherin 1 (CDH1) promoter constructs, and to determine the effect of a ZEB1 truncating mutation on CDH1 promoter activity. RESULTS ZEB1 exhibited binding to six of the nine COL4A3 E2 box probes, whereas no binding was observed for either of the two COL4A4 E2 box probes. ZEB1 overexpression resulted in reduced activity of the COL4A3 promoter construct containing all identified E2 box motifs, whereas a truncating ZEB1 mutation led to the loss of ZEB1-dependent repression of the CDH1 promoter. CONCLUSIONS COL4A3 gene expression is negatively regulated by ZEB1 binding to E2 box motifs in the COL4A3 promoter region. Therefore, the altered expression of type IV collagens, particularly COL4A3, in the corneal endothelium in individuals with PPCD3 is likely due to reduced transcriptional repression in the setting of a single functional ZEB1 allele.
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Affiliation(s)
- Duk-Won D. Chung
- Stein Eye Institute David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Ricardo F. Frausto
- Stein Eye Institute David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Stephan Chiu
- Stein Eye Institute David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Benjamin R. Lin
- Stein Eye Institute David Geffen School of Medicine at UCLA, Los Angeles, California, United States
| | - Anthony J. Aldave
- Stein Eye Institute David Geffen School of Medicine at UCLA, Los Angeles, California, United States
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Chou SF, Luo LJ, Lai JY, Ma DHK. On the importance of Bloom number of gelatin to the development of biodegradable in situ gelling copolymers for intracameral drug delivery. Int J Pharm 2016; 511:30-43. [PMID: 27374201 DOI: 10.1016/j.ijpharm.2016.06.129] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 06/14/2016] [Accepted: 06/29/2016] [Indexed: 01/27/2023]
Abstract
To overcome the drawbacks associated with conventional antiglaucoma eye drops, this work demonstrated the feasibility of an effective alternative strategy to administer pilocarpine directly via intracameral injections of drug-containing biodegradable in situ gelling GN copolymers composed of gelatin and poly(N-isopropylacrylamide). Specifically, this study aims to understand the importance of Bloom number of gelatin, a physicochemical parameter, to the development of GN carriers for intracameral drug delivery in glaucoma therapy. Our results showed that both imino acid and triple-helix contents increased with increasing Bloom index from 75-100 to 300. The drug encapsulation efficiency in response to temperature-triggered phase transition in GN copolymers was affected by the Bloom index of gelatin. In addition, the differences in protein secondary structure significantly influenced the degradation rates of GN carriers, which were highly correlated with drug release profiles. The increase in released pilocarpine concentration led to a high intracellular calcium level in rabbit ciliary smooth muscle cell cultures, indicating a beneficial pharmacological response to a drug. Irrespective of Bloom number of gelatin, all carrier materials exhibited excellent in vitro and in vivo biocompatibility with corneal endothelium. In a glaucomatous rabbit model, intracameral injections of pilocarpine-containing GN synthesized from gelatins with various Bloom numbers had different abilities to improve ocular hypertension and induce pupillary constriction, indicating distinct antiglaucoma efficacies due to in vivo drug release. It is concluded that the effects on pharmacological treatment using GN carriers for intracameral pilocarpine administration demonstrate a strong dependence on the Bloom number of gelatin.
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Affiliation(s)
- Shih-Feng Chou
- Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, 33302, Taiwan, ROC; Department of Bioengineering, University of Washington, Seattle, WA 98195-5061, USA
| | - Li-Jyuan Luo
- Department of Chemical and Materials Engineering, Chang Gung University, Taoyuan 33302, Taiwan, ROC
| | - Jui-Yang Lai
- Institute of Biochemical and Biomedical Engineering, Chang Gung University, Taoyuan, 33302, Taiwan, ROC; Biomedical Engineering Research Center, Chang Gung University, Taoyuan 33302, Taiwan, ROC; Molecular Medicine Research Center, Chang Gung University, Taoyuan 33302, Taiwan, ROC; Center for Tissue Engineering, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan, ROC; Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan, ROC.
| | - David Hui-Kang Ma
- Center for Tissue Engineering, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan, ROC; Department of Ophthalmology, Chang Gung Memorial Hospital, Taoyuan 33305, Taiwan, ROC; Department of Chinese Medicine, Chang Gung University, Taoyuan 33302, Taiwan, ROC
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Le DJ, Chung DWD, Frausto RF, Kim MJ, Aldave AJ. Identification of Potentially Pathogenic Variants in the Posterior Polymorphous Corneal Dystrophy 1 Locus. PLoS One 2016; 11:e0158467. [PMID: 27355326 PMCID: PMC4927100 DOI: 10.1371/journal.pone.0158467] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2015] [Accepted: 06/16/2016] [Indexed: 12/13/2022] Open
Abstract
Posterior polymorphous corneal dystrophy 1 (PPCD1) is a genetic disorder that affects corneal endothelial cell function and leads to loss of visual acuity. PPCD1 has been linked to a locus on chromosome 20 in multiple families; however, Sanger sequencing of protein-coding genes in the consensus region failed to identify any causative missense mutations. In this study, custom capture probes were utilized for targeted next-generation sequencing of the linked region in a previously reported family with PPCD1. Variants were detected through two bioinformatics pipelines and filtered according to multiple criteria. Additionally, a high-resolution microarray was used to detect copy number variations. No non-synonymous variants in the protein-coding region of annotated genes were identified. However, 12 single nucleotide variants in 10 genes, and 9 indels in 7 genes met the filtering criteria and were considered candidate variants for PPCD1. Eleven single nucleotide variants were confirmed by Sanger sequencing, including 2 synonymous variants and 9 non-coding variants, in 9 genes. One microdeletion was detected in an intron of OVOL2 by microarray but was subsequently not identified by PCR. Using a comprehensive next-generation sequencing approach, a total of 16 genes containing single nucleotide variants or indels that segregated with the affected phenotype in an affected family previously mapped to the PPCD1 locus were identified. Screening of these candidate genes in other families previously mapped to the PPCD1 locus will likely result in the identification of the genetic basis of PPCD1.
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Affiliation(s)
- Derek J. Le
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Duk-Won D. Chung
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Ricardo F. Frausto
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Michelle J. Kim
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
| | - Anthony J. Aldave
- Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America
- * E-mail:
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Shen AL, Moran SA, Glover EA, Drinkwater NR, Swearingen RE, Teixeira LB, Bradfield CA. Association of a Chromosomal Rearrangement Event with Mouse Posterior Polymorphous Corneal Dystrophy and Alterations in Csrp2bp, Dzank1, and Ovol2 Gene Expression. PLoS One 2016; 11:e0157577. [PMID: 27310661 PMCID: PMC4910986 DOI: 10.1371/journal.pone.0157577] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 06/01/2016] [Indexed: 12/26/2022] Open
Abstract
We have previously described a mouse model of human posterior polymorphous corneal dystrophy (PPCD) and localized the causative mutation to a 6.2 Mbp region of chromosome 2, termed Ppcd1. We now show that the gene rearrangement linked to mouse Ppcd1 is a 3.9 Mbp chromosomal inversion flanked by 81 Kbp and 542 bp deletions. This recombination event leads to deletion of Csrp2bp Exons 8 through 11, Dzank1 Exons 20 and 21, and the pseudogene Znf133. In addition, we identified translocation of novel downstream sequences to positions adjacent to Csrp2bp Exon 7 and Dzank1 Exon 20. Twelve novel fusion transcripts involving Csrp2bp or Dzank1 linked to downstream sequences have been identified. Eight are expressed at detectable levels in PPCD1 but not wildtype eyes. Upregulation of two Csrp2bp fusion transcripts, as well as upregulation of the adjacent gene, Ovol2, was observed. Absence of the PPCD1 phenotype in animals haploinsufficient for Csrp2bp or both Csrp2bp and Dzank1 rules out haploinsufficiency of these genes as a cause of mouse PPCD1. Complementation experiments confirm that PPCD1 embryonic lethality is due to disruption of Csrp2bp expression. The ocular expression pattern of Csrp2bp is consistent with a role for this protein in corneal development and pathogenesis of PPCD1.
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Affiliation(s)
- Anna L. Shen
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail: (CAB); (ALS)
| | - Susan A. Moran
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Edward A. Glover
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Norman R. Drinkwater
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Rebecca E. Swearingen
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States of America
| | - Leandro B. Teixeira
- Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison, Madison, WI, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Christopher A. Bradfield
- The McArdle Laboratory for Cancer Research, Department of Oncology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI, United States of America
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail: (CAB); (ALS)
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Davidson A, Liskova P, Evans C, Dudakova L, Nosková L, Pontikos N, Hartmannová H, Hodaňová K, Stránecký V, Kozmík Z, Levis H, Idigo N, Sasai N, Maher G, Bellingham J, Veli N, Ebenezer N, Cheetham M, Daniels J, Thaung C, Jirsova K, Plagnol V, Filipec M, Kmoch S, Tuft S, Hardcastle A. Autosomal-Dominant Corneal Endothelial Dystrophies CHED1 and PPCD1 Are Allelic Disorders Caused by Non-coding Mutations in the Promoter of OVOL2. Am J Hum Genet 2016; 98:75-89. [PMID: 26749309 PMCID: PMC4716680 DOI: 10.1016/j.ajhg.2015.11.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Accepted: 11/13/2015] [Indexed: 11/27/2022] Open
Abstract
Congenital hereditary endothelial dystrophy 1 (CHED1) and posterior polymorphous corneal dystrophy 1 (PPCD1) are autosomal-dominant corneal endothelial dystrophies that have been genetically mapped to overlapping loci on the short arm of chromosome 20. We combined genetic and genomic approaches to identify the cause of disease in extensive pedigrees comprising over 100 affected individuals. After exclusion of pathogenic coding, splice-site, and copy-number variations, a parallel approach using targeted and whole-genome sequencing facilitated the identification of pathogenic variants in a conserved region of the OVOL2 proximal promoter sequence in the index families (c.−339_361dup for CHED1 and c.−370T>C for PPCD1). Direct sequencing of the OVOL2 promoter in other unrelated affected individuals identified two additional mutations within the conserved proximal promoter sequence (c.−274T>G and c.−307T>C). OVOL2 encodes ovo-like zinc finger 2, a C2H2 zinc-finger transcription factor that regulates mesenchymal-to-epithelial transition and acts as a direct transcriptional repressor of the established PPCD-associated gene ZEB1. Interestingly, we did not detect OVOL2 expression in the normal corneal endothelium. Our in vitro data demonstrate that all four mutated OVOL2 promoters exhibited more transcriptional activity than the corresponding wild-type promoter, and we postulate that the mutations identified create cryptic cis-acting regulatory sequence binding sites that drive aberrant OVOL2 expression during endothelial cell development. Our data establish CHED1 and PPCD1 as allelic conditions and show that CHED1 represents the extreme of what can be considered a disease spectrum. They also implicate transcriptional dysregulation of OVOL2 as a common cause of dominantly inherited corneal endothelial dystrophies.
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The genetic and environmental factors for keratoconus. BIOMED RESEARCH INTERNATIONAL 2015; 2015:795738. [PMID: 26075261 PMCID: PMC4449900 DOI: 10.1155/2015/795738] [Citation(s) in RCA: 223] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/08/2015] [Accepted: 01/09/2015] [Indexed: 12/22/2022]
Abstract
Keratoconus (KC) is the most common cornea ectatic disorder. It is characterized by a cone-shaped thin cornea leading to myopia, irregular astigmatism, and vision impairment. It affects all ethnic groups and both genders. Both environmental and genetic factors may contribute to its pathogenesis. This review is to summarize the current research development in KC epidemiology and genetic etiology. Environmental factors include but are not limited to eye rubbing, atopy, sun exposure, and geography. Genetic discoveries have been reviewed with evidence from family-based linkage analysis and fine mapping in linkage region, genome-wide association studies, and candidate genes analyses. A number of genes have been discovered at a relatively rapid pace. The detailed molecular mechanism underlying KC pathogenesis will significantly advance our understanding of KC and promote the development of potential therapies.
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Frausto RF, Wang C, Aldave AJ. Transcriptome analysis of the human corneal endothelium. Invest Ophthalmol Vis Sci 2014; 55:7821-30. [PMID: 25377225 DOI: 10.1167/iovs.14-15021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
PURPOSE To comprehensively characterize human corneal endothelial cell (HCEnC) gene expression and age-dependent differential gene expression and to identify expressed genes mapped to chromosomal loci associated with the corneal endothelial dystrophies posterior polymorphous corneal dystrophy (PPCD)1, Fuchs endothelial corneal dystrophy (FECD)4, and X-linked endothelial dystrophy (XECD). METHODS Total RNA was isolated from ex vivo corneal endothelium obtained from six pediatric and five adult donor corneas. Complementary DNA was hybridized to the Affymetrix GeneChip 1.1ST array. Data analysis was performed using Partek Genomics Suite software, and differentially expressed genes were validated by digital molecular barcoding technology. RESULTS Transcripts corresponding to 12,596 genes were identified in HCEnC. Nine genes displayed the most significant differential expression between pediatric and adult HCEnC: CAPN6, HIST1H3A, HIST1H4E, and HSPA2 were expressed at higher levels in pediatric HCEnC, while ITGBL1, NALCN, PREX2, TAC1, and TMOD1 were expressed at higher levels in adult HCEnC. Analysis of the PPCD1, FECD4 and XECD loci demonstrated transcription of 53/95 protein-coding genes in the PPCD1 locus, 27/40 in the FECD4 locus, and 35/68 in the XECD locus. CONCLUSIONS An analysis of the HCEnC transcriptome reveals the expression of almost 13,000 genes, with less than 1% mapped to chromosomal loci associated with PPCD1, FECD4, and XECD. At least nine genes demonstrated significant differential expression between pediatric and adult HCEnC, defining specific functional properties distinct to each age group. These data will serve as a resource for vision scientists investigating HCEnC gene expression and can be used to focus the search for the genetic basis of the corneal endothelial dystrophies for which the genetic basis remains unknown.
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Affiliation(s)
- Ricardo F Frausto
- The Jules Stein Eye Institute, David Geffen School of Medicine at the University of California-Los Angeles, Los Angeles, California, United States
| | - Cynthia Wang
- The Jules Stein Eye Institute, David Geffen School of Medicine at the University of California-Los Angeles, Los Angeles, California, United States
| | - Anthony J Aldave
- The Jules Stein Eye Institute, David Geffen School of Medicine at the University of California-Los Angeles, Los Angeles, California, United States
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Han J, Young JW, Frausto RF, Isenberg SJ, Aldave AJ. X-linked Megalocornea Associated with the Novel CHRDL1 Gene Mutation p.(Pro56Leu*8). Ophthalmic Genet 2013; 36:145-8. [PMID: 24073597 DOI: 10.3109/13816810.2013.837187] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND The genetic basis of X-linked megalocornea (MGC1) was reported in 2012 to be caused by mutations in the CHRDL1 gene. We sought to confirm that mutations in CHRDL1 are associated with MGC1 in a previously unreported pedigree. MATERIALS AND METHODS Slit lamp examination, corneal pachymetry, corneal topography and DNA collection for screening of the CHRDL1 gene were performed for members of an affected family. RESULTS Examination of a woman and her four sons, ranging in age between 3 and 15 years, demonstrated horizontal corneal diameters of 14 mm in three of the four sons and a normal corneal diameter of 12 mm in the mother and other son. Central corneal thickness in the individuals with enlarged corneal diameters averaged 474 microns, compared to 604 microns in their unaffected brother. Corneal topographic imaging demonstrated an average K value of 44.4 D in the affected individuals compared with 41.6 D in their unaffected sibling. Screening of the CHRDL1 gene demonstrated the novel hemizygous frameshift mutation c.167delC (p.(Pro56Leu*8)) in exon 3 in the affected individuals and in the heterozygous state in their mother. This mutation was not present in the unaffected brother or in unrelated controls. CONCLUSION We provide the initial confirmation that X-linked megalocornea is associated with mutations in the CHRDL1 gene.
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Affiliation(s)
- Jonathan Han
- The Jules Stein Eye Institute, David Geffen School of Medicine at UCLA , Los Angeles , California
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Vincent AL. Corneal dystrophies and genetics in the International Committee for Classification of Corneal Dystrophies era: a review. Clin Exp Ophthalmol 2013; 42:4-12. [PMID: 24433354 DOI: 10.1111/ceo.12149] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 06/06/2013] [Indexed: 02/02/2023]
Abstract
Many of the corneal dystrophies have now been genetically characterized, and a system was established in 2008 by The International Committee for Classification of Corneal Dystrophies (IC3D) in an attempt to standardize the nomenclature. IC3D provided a classification system whereby all dystrophies can be categorized on the basis of the underlying genetic knowledge. Since that time, further work has established even more phenotypic and allelic heterogeneity than anticipated, particular for Fuchs endothelial corneal dystrophy and posterior polymorphous dystrophy. Using genome-wide association studies, a number of genes are now implicated both in normal corneal quantitative traits, such as central corneal thickness, as well as in disease. There is also a trend towards functional characterization of the genetic variants involved to elucidate the pathophysiology of these entities. This review article will provide an overview of the knowledge to date, with an emphasis on findings since the IC3D classification was published in 2008.
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Affiliation(s)
- Andrea L Vincent
- Department of Ophthalmology, National Eye Centre, Faculty of Medical and Health Science, University of Auckland, Auckland, New Zealand
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Aldave AJ, Han J, Frausto RF. Genetics of the corneal endothelial dystrophies: an evidence-based review. Clin Genet 2013; 84:109-19. [PMID: 23662738 DOI: 10.1111/cge.12191] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Revised: 05/08/2013] [Accepted: 05/08/2013] [Indexed: 11/27/2022]
Abstract
The aim of this review was to provide an evidenced-based review of the genetic basis of the corneal endothelial dystrophies. A review of the English language peer-reviewed literature describing the molecular genetic basis of posterior polymorphous corneal dystrophy (PPCD), congenital hereditary endothelial dystrophy (CHED), Fuchs endothelial corneal dystrophy (FECD) and X-linked endothelial corneal dystrophy (XECD) was performed. Mutations in several genes have been implicated as playing a pathogenic role in the corneal endothelial dystrophies: VSX1 mutations in PPCD1; COL8A2 mutations in PPCD2 and FECD; ZEB1 mutations in PPCD3 and FECD; and SLC4A11 mutations in CHED2 and FECD. However, linkage, association and familial segregation analyses support a role of only one gene in each corneal endothelial dystrophy: ZEB1 in PPCD3, SLC4A11 in CHED2 and COL8A2 in FECD (early onset). In addition, insufficient evidence exists to consider the autosomal dominant form of CHED (CHED1) as distinct from PPCD. An accurate classification of the corneal endothelial dystrophies requires a critical review of the evidence to support the role of each suggested chromosomal locus, gene and genetic mutation associated with a corneal endothelial dystrophy. Only after the separation of evidence from opinion is performed can a critical examination of the molecular pathways that lead to endothelial dysfunction in each of these disorders be accurately performed.
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Key Words
- corneal dystrophy, Fuchs endothelial, 1
- corneal dystrophy, Fuchs endothelial, 2
- corneal dystrophy, Fuchs endothelial, early onset
- corneal dystrophy, Fuchs endothelial, late onset
- corneal dystrophy, posterior polymorphous, 1
- corneal dystrophy, posterior polymorphous, 2
- corneal dystrophy, posterior polymorphous, 3
- corneal endothelial dystrophy 1
- corneal endothelial dystrophy 2
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Affiliation(s)
- A J Aldave
- The Jules Stein Eye Institute, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095–7003, USA.
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High prevalence of posterior polymorphous corneal dystrophy in the Czech Republic; linkage disequilibrium mapping and dating an ancestral mutation. PLoS One 2012; 7:e45495. [PMID: 23049806 PMCID: PMC3458081 DOI: 10.1371/journal.pone.0045495] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 08/17/2012] [Indexed: 11/19/2022] Open
Abstract
Posterior polymorphous corneal dystrophy (PPCD) is a rare autosomal dominant genetically heterogeneous disorder. Nineteen Czech PPCD pedigrees with 113 affected family members were identified, and 17 of these kindreds were genotyped for markers on chromosome 20p12.1- 20q12. Comparison of haplotypes in 81 affected members, 20 unaffected first degree relatives and 13 spouses, as well as 55 unrelated controls, supported the hypothesis of a shared ancestor in 12 families originating from one geographic location. In 38 affected individuals from nine of these pedigrees, a common haplotype was observed between D20S48 and D20S107 spanning approximately 23 Mb, demonstrating segregation of disease with the PPCD1 locus. This haplotype was not detected in 110 ethnically matched control chromosomes. Within the common founder haplotype, a core mini-haplotype was detected for D20S605, D20S182 and M189K2 in all 67 affected members from families 1-12, however alleles representing the core mini-haplotype were also detected in population matched controls. The most likely location of the responsible gene within the disease interval, and estimated mutational age, were inferred by linkage disequilibrium mapping (DMLE+2.3). The appearance of a disease-causing mutation was dated between 64-133 generations. The inferred ancestral locus carrying a PPCD1 disease-causing variant within the disease interval spans 60 Kb on 20p11.23, which contains a single known protein coding gene, ZNF133. However, direct sequence analysis of coding and untranslated exons did not reveal a potential pathogenic mutation. Microdeletion or duplication was also excluded by comparative genomic hybridization using a dense chromosome 20 specific array. Geographical origin, haplotype and statistical analysis suggest that in 14 unrelated families an as yet undiscovered mutation on 20p11.23 was inherited from a common ancestor. Prevalence of PPCD in the Czech Republic appears to be the highest worldwide and our data suggests that at least one other novel locus for PPCD also exists.
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Abstract
PURPOSE The visual system homeobox 1 (VSX1) gene variants have recently been shown to be associated with keratoconus. To replicate this finding, we performed a genetic analysis of the VSX1 gene in a Korean case-control sample. METHODS Patients with keratoconus and healthy control subjects were recruited from Seoul National University Hospital. A diagnosis of keratoconus was made based on clinical examinations and the presence of characteristic topographic features. For all patients and controls, the whole coding region and the exon-intron junctions of the VSX1 gene were analyzed by direct sequencing. RESULTS Fifty-three patients with keratoconus and 100 healthy volunteers were included. We observed 2 novel missense substitutions (Leu17Val and Val199Leu) and 1 previously reported substitution (Gly160Val) in 6 of the 53 affected probands. Because these substitutions have been identified in unaffected individuals, they were not considered to be pathogenic. No intragenic polymorphism was associated with a significantly increased risk of keratoconus. CONCLUSIONS We cannot confirm the previously reported association of the VSX1 gene variants with keratoconus. Our results suggest that the VSX1 gene and its mutations with amino acid changes do not play a major role in the pathogenesis of keratoconus.
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Snyder EE, Walts B, Pérusse L, Chagnon YC, Weisnagel SJ, Rankinen T, Bouchard C. The Human Obesity Gene Map: The 2003 Update. ACTA ACUST UNITED AC 2012; 12:369-439. [PMID: 15044658 DOI: 10.1038/oby.2004.47] [Citation(s) in RCA: 207] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
This is the tenth update of the human obesity gene map, incorporating published results up to the end of October 2003 and continuing the previous format. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, quantitative trait loci (QTLs) from human genome-wide scans and animal crossbreeding experiments, and association and linkage studies with candidate genes and other markers is reviewed. Transgenic and knockout murine models relevant to obesity are also incorporated (N = 55). As of October 2003, 41 Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. QTLs reported from animal models currently number 183. There are 208 human QTLs for obesity phenotypes from genome-wide scans and candidate regions in targeted studies. A total of 35 genomic regions harbor QTLs replicated among two to five studies. Attempts to relate DNA sequence variation in specific genes to obesity phenotypes continue to grow, with 272 studies reporting positive associations with 90 candidate genes. Fifteen such candidate genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, more than 430 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful sites can be found at http://obesitygene.pbrc.edu.
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Affiliation(s)
- Eric E Snyder
- Human Genomics Laboratory, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, Louisiana 70808-4124, USA
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Pérusse L, Rankinen T, Zuberi A, Chagnon YC, Weisnagel SJ, Argyropoulos G, Walts B, Snyder EE, Bouchard C. The Human Obesity Gene Map: The 2004 Update. ACTA ACUST UNITED AC 2012; 13:381-490. [PMID: 15833932 DOI: 10.1038/oby.2005.50] [Citation(s) in RCA: 212] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
This paper presents the eleventh update of the human obesity gene map, which incorporates published results up to the end of October 2004. Evidence from single-gene mutation obesity cases, Mendelian disorders exhibiting obesity as a clinical feature, transgenic and knockout murine models relevant to obesity, quantitative trait loci (QTLs) from animal cross-breeding experiments, association studies with candidate genes, and linkages from genome scans is reviewed. As of October 2004, 173 human obesity cases due to single-gene mutations in 10 different genes have been reported, and 49 loci related to Mendelian syndromes relevant to human obesity have been mapped to a genomic region, and causal genes or strong candidates have been identified for most of these syndromes. There are 166 genes which, when mutated or expressed as transgenes in the mouse, result in phenotypes that affect body weight and adiposity. The number of QTLs reported from animal models currently reaches 221. The number of human obesity QTLs derived from genome scans continues to grow, and we have now 204 QTLs for obesity-related phenotypes from 50 genome-wide scans. A total of 38 genomic regions harbor QTLs replicated among two to four studies. The number of studies reporting associations between DNA sequence variation in specific genes and obesity phenotypes has also increased considerably with 358 findings of positive associations with 113 candidate genes. Among them, 18 genes are supported by at least five positive studies. The obesity gene map shows putative loci on all chromosomes except Y. Overall, >600 genes, markers, and chromosomal regions have been associated or linked with human obesity phenotypes. The electronic version of the map with links to useful publications and genomic and other relevant sites can be found at http://obesitygene.pbrc.edu.
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Affiliation(s)
- Louis Pérusse
- Division of Kinesiology, Department of Social and Preventive Medicine, Faculty of Medicine, Laval University, Sainte-Foy, Québec, Canada
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Yellore VS, Rayner SA, Nguyen CK, Gangalum RK, Jing Z, Bhat SP, Aldave AJ. Analysis of the role of ZEB1 in the pathogenesis of posterior polymorphous corneal dystrophy. Invest Ophthalmol Vis Sci 2012; 53:273-8. [PMID: 22199242 DOI: 10.1167/iovs.11-8038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To determine how nonsense mutations in the transcription factor ZEB1 lead to the development of posterior polymorphous corneal dystrophy type 3 (PPCD3). METHODS Whole-cell extracts were obtained from cultured human corneal epithelial cells (HCEpCs) as a source of ZEB1 protein. DNA-binding assays were performed using the whole-cell extract and oligonucleotide probes consisting of the two conserved E2-box motifs and surrounding nucleotides upstream of COL4A3. ZEB1 and COL4A3 mRNA expression in primary human corneal endothelial cells (HCEnCs) was assayed in both PPCD3 and control corneas by RT-PCR. Immunohistochemistry was used to localize ZEB1 and COL4A3 expression in normal human cornea. RESULTS Electromobility shift assays (EMSAs) and competition EMSAs demonstrated binding of protein(s) in the cultured HCEpCs to the E2-box motifs in the probes. The supershift EMSA confirmed that ZEB1, demonstrated to be present in the whole-cell extracts, binds to both the proximal and distal E2-box motifs in the COL4A3 promoter region. Both COL4A3 and ZEB1 are expressed in normal HCEnCs, although in PPCD3, ZEB1 expression is decreased and COL4A3 expression is increased compared with levels of both genes in healthy control corneas. CONCLUSIONS Inversely related HCEnC expression levels of ZEB1 and COL4A3 in PPCD3 indicate that ZEB1-mediated alterations in COL4A3 expression are most likely associated with the pathogenesis of this corneal endothelial dystrophy. However, the demonstration of COL4A3 expression in healthy adult primary HCEnCs suggests that PPCD3 is more likely to involve an alteration in the timing and/or degree of COL4A3 expression than to result from the dichotomous change implied by the previously proposed ectopic expression model.
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Affiliation(s)
- Vivek S Yellore
- Jules Stein Eye Institute, David Geffen School of Medicine at the University of California, Los Angeles, California, USA
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Abstract
Keratoconus is the most common ectatic disorder of the corneal. Genetic and environmental factors may contribute to its pathogenesis. The focus of this article is to summarize current research into the complex genetics of keratoconus. We discuss the evidence of genetic etiology including family-based linkage studies, twin studies, genetic mutations, and genome-wide association studies. The genes implicated potentially include VSX1, miR-184, DOCK9, SOD1, RAB3GAP1, and HGF. Besides the coding mutations, we also highlight the potential contribution of DNA copy number variants in the pathogenesis of keratoconus. Finally, we present future directions for genetic research in the understanding of the complex genetics of keratoconus and its clinical significance. As new functional, candidate genes for keratoconus are being discovered at a rapid pace, the molecular genetic mechanisms underlying keratoconus pathogenesis will advance our understanding of keratoconus and promote the development of a novel therapy.
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Affiliation(s)
- Joshua Wheeler
- Center for Human Genetics, Department of Medicine, Duke University Medical Center, Durham, NC, USA 27710
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Schmedt T, Silva MM, Ziaei A, Jurkunas U. Molecular bases of corneal endothelial dystrophies. Exp Eye Res 2011; 95:24-34. [PMID: 21855542 DOI: 10.1016/j.exer.2011.08.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2011] [Revised: 07/18/2011] [Accepted: 08/03/2011] [Indexed: 01/12/2023]
Abstract
The phrase "corneal endothelial dystrophies" embraces a group of bilateral corneal conditions that are characterized by a non-inflammatory and progressive degradation of corneal endothelium. Corneal endothelial cells exhibit a high pump site density and, along with barrier function, are responsible for maintaining the cornea in its natural state of relative dehydration. Gradual loss of endothelial cells leads to an insufficient water outflow, resulting in corneal edema and loss of vision. Since the pathologic mechanisms remain largely unknown, the only current treatment option is surgical transplantation when vision is severely impaired. In the past decade, important steps have been taken to understand how endothelial degeneration progresses on the molecular level. Studies of affected multigenerational families and sporadic cases identified genes and chromosomal loci, and revealed either Mendelian or complex disorder inheritance patterns. Mutations have been detected in genes that carry important structural, metabolic, cytoprotective, and regulatory functions in corneal endothelium. In addition to genetic predisposition, environmental factors like oxidative stress were found to be involved in the pathogenesis of endotheliopathies. This review summarizes and crosslinks the recent progress on deciphering the molecular bases of corneal endothelial dystrophies.
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Affiliation(s)
- Thore Schmedt
- Schepens Eye Research Institute, Boston, MA 02114, USA
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Espandar L, Meyer J. Keratoconus: overview and update on treatment. Middle East Afr J Ophthalmol 2011; 17:15-20. [PMID: 20543932 PMCID: PMC2880369 DOI: 10.4103/0974-9233.61212] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Keratoconus is a non-inflammatory, progressive thinning process of the cornea. It is a relatively common disorder of unknown etiology that can involve each layer of the cornea and often leads to high myopia and astigmatism. Computer- assisted corneal topography devices are valuable diagnostic tools for the diagnosis of subclinical keratoconus and for tracking the progression of the disease. The traditional conservative management of keratoconus begins with spectacle correction and contact lenses. Several newer, more invasive, treatments are currently available, especially for contact lens-intolerant patients. Intrastromal corneal ring segments can be used to reshape the abnormal cornea to improve the topographic abnormalities and visual acuity. Phakic intraocular lenses such as iris-fixated, angle-supported, posterior chamber implantable collamer and toric lenses are additional valuable options for the correction of refractive error. Corneal cross-linking is a relatively new method of stiffening the cornea to halt the progression of the disease. The future management of keratoconus will most likely incorporate multiple treatment modalities, both simultaneous and sequential, for the prevention and treatment of this disease.
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Affiliation(s)
- Ladan Espandar
- Department of Ophthalmology, Tulane University, New Orleans, LA, USA
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Liskova P, Filipec M, Merjava S, Jirsova K, Tuft SJ. Variable ocular phenotypes of posterior polymorphous corneal dystrophy caused by mutations in the ZEB1 gene. Ophthalmic Genet 2011; 31:230-4. [PMID: 21067486 DOI: 10.3109/13816810.2010.518577] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To describe the ocular features of 6 Czech and British patients with posterior polymorphous corneal dystrophy (PPCD) caused by mutations in the zinc finger E-box binding homeobox 1 gene (ZEB1). METHODS Case note review of 4 individuals with p.E776fs mutation, one with p.Y719X and one with p.F375fs mutation within the ZEB1 gene. RESULTS Five individuals exhibited endothelial and Descemet membrane changes consistent with the diagnosis of PPCD. We concluded that one 70-year-old female who had a normal endothelium at both slit lamp and non-contact specular microscopy was a case of non-penetrance. The onset of disease was as early as 3 months after birth. One patient had irregular astigmatism with inferior corneal steepening on videokeratography, but without corneal thinning or other signs of keratoconus. Two others had corneal steepening >49D but with regular astigmatism. Three individuals underwent penetrating keratoplasty (PK) in 1 eye, with one patient treated for secondary glaucoma prior to the PK. CONCLUSIONS The phenotype associated with changes in the ZEB1 gene exhibits variable expression and incomplete penetrance and seems to have a low risk for secondary glaucoma or the need for keratoplasty compared to PPCD linked to 20p11.2. There is insufficient data for phenotype correlations with PPCD caused by other genes.
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Affiliation(s)
- Petra Liskova
- Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General Teaching Hospital in Prague, Czech Republic.
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Molecular Genetics of Corneal Disease. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00019-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Weisenthal RW, Streeten BW. Descemet's Membrane and Endothelial Dystrophies. Cornea 2011. [DOI: 10.1016/b978-0-323-06387-6.00080-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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Unusual presentation of presumed posterior polymorphous dystrophy associated with iris heterochromia, band keratopathy, and keratoconus. Cornea 2010; 29:1180-5. [PMID: 20567203 DOI: 10.1097/ico.0b013e3181d007e1] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To report an unusual presentation of posterior polymorphous corneal dystrophy (PPCD) associated with band keratopathy, iridocorneal adhesions, heterochromia, keratoconus, and confocal microscopic findings suggestive of iridocorneal endothelial syndrome. METHODS Confocal microscopy, corneal topography, electroretinography, and genetic analysis were performed in the proband and his siblings. RESULTS A 23-year-old man presented with decreased vision in both eyes over 9 months. Examination revealed bilateral alterations in corneal endothelial mosaic with corneal edema and beaten metal appearance in the right eye and cystoid endothelial opacities in the left eye. Marked heterochromia, band keratopathy, and broad peripheral anterior synechiae were present in both eyes. Topographic features of keratoconus were noted. Electroretinography did not detect abnormal retinal function, as has been described with PPCD associated with VSX1 mutations. Diagnosis of PPCD was postulated on the basis of the examination of 3 of proband's brothers by confocal microscopy. Genetic analysis of 3 known PPCD genes, VSX1, COL8A2, and TCF8, did not detect any mutations. CONCLUSIONS In severe cases, PPCD can resemble iridocorneal endothelial syndromes in both clinical appearance and imaging studies (confocal microscopy). There was a strong genetic phenotypic penetrance in the family, which was essential in the diagnostic decision making. A yet undetermined genotype is contributing to this unusual PPCD phenotype.
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Nguyen DQ, Hosseini M, Billingsley G, Héon E, Churchill AJ. Clinical phenotype of posterior polymorphous corneal dystrophy in a family with a novel ZEB1 mutation. Acta Ophthalmol 2010; 88:695-9. [PMID: 19432861 DOI: 10.1111/j.1755-3768.2009.01511.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE To describe the clinical phenotype in a family with posterior polymorphous corneal dystrophy (PPCD) and a novel mutation in the ZEB1 gene. METHODS Clinical examination, anterior segment photography, specular microscopy and electrophysiological investigations were performed and quantified. Genomic DNA extracted from peripheral blood was sequenced for ZEB1 exons. Cosegregation of identified mutation with the disease status in the family was confirmed using polymerase chain reaction and restriction fragment length polymorphism. RESULTS Ocular examination was performed on five family members from two generations. Three had anomalies of the corneal endothelium that were consistent with PPCD. Endothelial cell counts ranged from 2306 to 2987 mm(2) (ref. 2000-4000 cells/mm(2) ). No evidence of glaucoma or retinal abnormalities was observed. Extraocular abnormalities such as inguinal herniation, hydrocoele and possible bony or connective tissue anomalies were part of the disease spectrum in this family. Mutation analysis revealed a novel change in exon 5 of ZEB1 (c.672delA) that cosegregated with the affected disease status. CONCLUSION The detailed clinical features of PPCD associated with a novel ZEB1 mutation are supportive of the previously proposed range of phenotype parameters. Further phenotype-genotype correlations may provide insights into the clinical variability and pathological processes affecting the corneal endothelium, Descemet's membrane, retinal photoreceptor function and extraocular tissues of some patients.
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Affiliation(s)
- Dan Q Nguyen
- Department of Ophthalmology, Bristol Eye Hospital, UK
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Shen AL, O'Leary KA, Dubielzig RR, Drinkwater N, Murphy CJ, Kasper CB, Bradfield CA. The PPCD1 mouse: characterization of a mouse model for posterior polymorphous corneal dystrophy and identification of a candidate gene. PLoS One 2010; 5:e12213. [PMID: 20808945 PMCID: PMC2922377 DOI: 10.1371/journal.pone.0012213] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Accepted: 07/24/2010] [Indexed: 11/18/2022] Open
Abstract
The PPCD1 mouse, a spontaneous mutant that arose in our mouse colony, is characterized by an enlarged anterior chamber resulting from metaplasia of the corneal endothelium and blockage of the iridocorneal angle by epithelialized corneal endothelial cells. The presence of stratified multilayered corneal endothelial cells with abnormal patterns of cytokeratin expression are remarkably similar to those observed in human posterior polymorphous corneal dystrophy (PPCD) and the sporadic condition, iridocorneal endothelial syndrome. Affected eyes exhibit epithelialized corneal endothelial cells, with inappropriate cytokeratin expression and proliferation over the iridocorneal angle and posterior cornea. We have termed this the “mouse PPCD1” phenotype and mapped the mouse locus for this phenotype, designated “Ppcd1”, to a 6.1 Mbp interval on Chromosome 2, which is syntenic to the human Chromosome 20 PPCD1 interval. Inheritance of the mouse PPCD1 phenotype is autosomal dominant, with complete penetrance on the sensitive DBA/2J background and decreased penetrance on the C57BL/6J background. Comparative genome hybridization has identified a hemizygous 78 Kbp duplication in the mapped interval. The endpoints of the duplication are located in positions that disrupt the genes Csrp2bp and 6330439K17Rik and lead to duplication of the pseudogene LOC100043552. Quantitative reverse transcriptase-PCR indicates that expression levels of Csrp2bp and 6330439K17Rik are decreased in eyes of PPCD1 mice. Based on the observations of decreased gene expression levels, association with ZEB1-related pathways, and the report of corneal opacities in Csrp2bptm1a(KOMP)Wtsi heterozygotes and embryonic lethality in nulls, we postulate that duplication of the 78 Kbp segment leading to haploinsufficiency of Csrp2bp is responsible for the mouse PPCD1 phenotype. Similarly, CSRP2BP haploinsufficiency may lead to human PPCD.
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Affiliation(s)
- Anna L Shen
- McArdle Laboratory for Cancer Research, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, Wisconsin, United States of America.
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Abstract
The corneal endothelium maintains the level of hydration in the cornea. Dysfunction of the endothelium results in excess accumulation of water in the corneal stroma, leading to swelling of the stroma and loss of transparency. There are four different corneal endothelial dystrophies that are hereditary, progressive, non-inflammatory disorders involving dysfunction of the corneal endothelium. Each of the endothelial dystrophies is genetically heterogeneous with different modes of transmission and/or different genes involved in each subtype. Genes responsible for disease have been identified for only a subset of corneal endothelial dystrophies. Knowledge of genes involved and their function in the corneal endothelium can aid understanding the pathogenesis of the disorder as well as reveal pathways that are important for normal functioning of the endothelium.
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Exclusion of positional candidate gene coding region mutations in the common posterior polymorphous corneal dystrophy 1 candidate gene interval. Cornea 2009; 28:801-7. [PMID: 19574904 DOI: 10.1097/ico.0b013e31819672fb] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE Posterior polymorphous corneal dystrophy (PPCD) is an autosomal-dominant disorder of the corneal endothelium associated with visually significant corneal edema and glaucoma. Statistical genetic analysis of 4 families with PPCD has demonstrated linkage to a 2.4 cM common support interval on chromosome 20 bordered by the markers D20S182 and D20S139. We sought to identify the genetic basis of PPCD linked to chromosome 20 (PPCD1) by screening the 26 positional candidate genes between these markers in a family previously mapped to the PPCD1 region. METHODS The coding regions of the 26 positional candidate genes mapped to the common PPCD1 support interval were amplified and sequenced in affected and unaffected individuals from a family previously linked to the PPCD1 locus. Nine other genes positioned just outside of the common PPCD1 support interval but within the autosomal-dominant congenital hereditary endothelial dystrophy interval were also screened. RESULTS Four DNA sequence variants in 3 of the positional candidate genes demonstrated complete segregation with the affected phenotype: p.Thr109Thr (rs6111803) in OVOL2, p.Arg56Gln (novel variant-RPSnovel) in RPS19P1, and p.Thr85Thr (rs1053834) and p.Pro99Ser (rs1053839) in C20orf79. Each of these 4 sequence variants demonstrated significant linkage with the affected phenotype in this family (P = 2.5 x 10 for RPSnovel, rs1053834 and rs1053839; P = 8.6 x 10 for rs6111803). However, we also identified each of these 4 sequence variants in > or = affected control individuals. The haplotype on which the disease-causing mutation is segregating was found to have a population frequency of 4.2% in the CEPH HapMap trios. Although a number of other previously described and novel single nucleotide polymorphisms were identified in the 35 positional candidate genes located within the PPCD1 and congenital hereditary endothelial dystrophy intervals, none segregated with the affected phenotype. CONCLUSIONS We report the absence of a presumed pathogenic coding region mutation in the common PPCD1 support interval. Although minor alleles of 4 single nucleotide polymorphisms were identified that segregated with the affected phenotype, the relatively high frequency of each minor allele in the general population indicates that none is a candidate for the causal variant for PPCD. Instead, the causal variant is most likely a coding region deletion or a variant in a noncoding region of the PPCD1 common support interval.
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Mutational screening of VSX1 in keratoconus patients from the European population. Eye (Lond) 2009; 24:1085-92. [DOI: 10.1038/eye.2009.217] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Cohn AC, Kearns LS, Savarirayan R, Ryan J, Craig JE, Mackey DA. Chromosomal Abnormalities and Glaucoma: A Case of Congenital Glaucoma with Trisomy 8q22-Qter/ Monosomy 9p23-Pter. Ophthalmic Genet 2009; 26:45-53. [PMID: 15823925 DOI: 10.1080/13816810590918398] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
PURPOSE To present a case of congenital glaucoma with an unbalanced translocation trisomy 8q22-qter/monosomy 9p23-pter, resulting in trisomy of the GLC1D locus. To perform a literature review of chromosomal abnormalities associated with glaucoma. METHOD A case report of a family with balanced translocation without glaucoma and unbalanced translocation with congenital glaucoma. PubMed and OMIM databases were searched for reports of chromosomal abnormalities and glaucoma. RESULTS Other case reports of congenital glaucoma with chromosomal abnormalities in this region were identified. A review of cytogenetics in southeastern Australia found nine cases involving the loss of 9p23 and 10 cases involving mosaicism for trisomy 8, but none had congenital glaucoma. A review of the literature identified reports of glaucoma and chromosomal abnormalities in regions with glaucoma loci mapped by conventional linkage analysis. These include the loci GLC1B, GLC1C, GLC1D, GLC1F, GPDS1, and RIEG2. CONCLUSION The study of patients with glaucoma and chromosomal abnormalities may help to identify new glaucoma genes. Ophthalmologists can assist with this by requesting cytogenetic studies on congenital and developmental glaucoma cases and interacting with ophthalmic genetics researchers.
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Affiliation(s)
- Amy C Cohn
- Department of Ophthalmology, Royal Victorian Eye and Ear Hospital, 32 Gisborne Street, Eats Melbourne, VIC 3002, Australia
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Abstract
The term corneal dystrophy embraces a heterogenous group of bilateral genetically determined non-inflammatory corneal diseases that are restricted to the cornea. The designation is imprecise but remains in vogue because of its clinical value. Clinically, the corneal dystrophies can be divided into three groups based on the sole or predominant anatomical location of the abnormalities. Some affect primarily the corneal epithelium and its basement membrane or Bowman layer and the superficial corneal stroma (anterior corneal dystrophies), the corneal stroma (stromal corneal dystrophies), or Descemet membrane and the corneal endothelium (posterior corneal dystrophies). Most corneal dystrophies have no systemic manifestations and present with variable shaped corneal opacities in a clear or cloudy cornea and they affect visual acuity to different degrees. Corneal dystrophies may have a simple autosomal dominant, autosomal recessive or X-linked recessive Mendelian mode of inheritance. Different corneal dystrophies are caused by mutations in the CHST6, KRT3, KRT12, PIP5K3, SLC4A11, TACSTD2, TGFBI, and UBIAD1 genes. Knowledge about the responsible genetic mutations responsible for these disorders has led to a better understanding of their basic defect and to molecular tests for their precise diagnosis. Genes for other corneal dystrophies have been mapped to specific chromosomal loci, but have not yet been identified. As clinical manifestations widely vary with the different entities, corneal dystrophies should be suspected when corneal transparency is lost or corneal opacities occur spontaneously, particularly in both corneas, and especially in the presence of a positive family history or in the offspring of consanguineous parents. Main differential diagnoses include various causes of monoclonal gammopathy, lecithin-cholesterol-acyltransferase deficiency, Fabry disease, cystinosis, tyrosine transaminase deficiency, systemic lysosomal storage diseases (mucopolysaccharidoses, lipidoses, mucolipidoses), and several skin diseases (X-linked ichthyosis, keratosis follicularis spinolosa decalvans). The management of the corneal dystrophies varies with the specific disease. Some are treated medically or with methods that excise or ablate the abnormal corneal tissue, such as deep lamellar endothelial keratoplasty (DLEK) and phototherapeutic keratectomy (PTK). Other less debilitating or asymptomatic dystrophies do not warrant treatment. The prognosis varies from minimal effect on the vision to corneal blindness, with marked phenotypic variability.
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Affiliation(s)
- Gordon K Klintworth
- Department of Ophthalmology, Duke University Medical Center, Durham, North Carolina, USA.
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Merjava S, Liskova P, Sado Y, Davis PF, Greenhill NS, Jirsova K. Changes in the localization of collagens IV and VIII in corneas obtained from patients with posterior polymorphous corneal dystrophy. Exp Eye Res 2009; 88:945-52. [PMID: 19162009 DOI: 10.1016/j.exer.2008.12.017] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 12/08/2008] [Accepted: 12/09/2008] [Indexed: 11/15/2022]
Abstract
Posterior polymorphous corneal dystrophy (PPCD) is a hereditary bilateral disorder affecting primarily the endothelium and Descemet's membrane (DM). The aim of this study was to determine the changes in the presence and localization of the alpha1-alpha6 collagen IV chains and alpha1, alpha2 collagen VIII chains in Czech patients with PPCD. Twelve corneal buttons from ten PPCD patients who underwent corneal grafting, as well as eight unaffected corneas, were used. Enzymatic indirect immunohistochemistry was performed on cryosections using antibodies against the alpha1-alpha6 collagen IV chains and alpha1, alpha2 collagen VIII chains. The intensity of the signal was examined separately in the basal membrane of the epithelium (BME), stroma and DM. More than 50% of PPCD specimens exhibited positivity for alpha1 and alpha2 collagen IV chains in the BME and in the posterior stroma, while no staining was detected in these areas in control specimens. The signal for the alpha1 and alpha2 collagen IV chains was more intense in DM of PPCD corneas compared to controls and it was shifted from the stromal side (in control tissue) to the endothelial side of DM (in the patients). A less intensive signal in PPCD corneas for the alpha3 and alpha5 chains in DM and an accumulation of alpha3-alpha5 in the posterior stroma in diseased corneas were the only differences in staining for the alpha3-alpha6 collagen IV chains. The alpha1 collagen VIII chain was detected on both the endothelial and the stromal sides of DM in 90% of patients with PPCD, compared with the prevailing localization on the stromal side of DM in control corneas. A change in the localization of the alpha2 collagen VIII chain in DM from vertically striated features in control specimens to double line positivity in the DM of PPCD corneas and positive staining in the posterior collagenous layer of four patients were also detected. In three PPCD patients a fibrous pannus located under the BME, positive for alpha1-alpha3, alpha5 collagen IV chains and alpha1 collagen VIII chain, was observed. The increased expression of the alpha1, alpha2 collagen IV and alpha1 collagen VIII chains and the change in their localization in DM may contribute to the increased endothelial proliferative capacity observed in PPCD patients.
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Affiliation(s)
- Stanislava Merjava
- Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, General Teaching Hospital and First Faculty of Medicine, Charles University in Prague, Czech Republic
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Weiss JS, Møller HU, Lisch W, Kinoshita S, Aldave AJ, Belin MW, Kivelä T, Busin M, Munier FL, Seitz B, Sutphin J, Bredrup C, Mannis MJ, Rapuano CJ, Van Rij G, Kim EK, Klintworth GK. The IC3D classification of the corneal dystrophies. Cornea 2008; 27 Suppl 2:S1-83. [PMID: 19337156 PMCID: PMC2866169 DOI: 10.1097/ico.0b013e31817780fb] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND The recent availability of genetic analyses has demonstrated the shortcomings of the current phenotypic method of corneal dystrophy classification. Abnormalities in different genes can cause a single phenotype, whereas different defects in a single gene can cause different phenotypes. Some disorders termed corneal dystrophies do not appear to have a genetic basis. PURPOSE The purpose of this study was to develop a new classification system for corneal dystrophies, integrating up-to-date information on phenotypic description, pathologic examination, and genetic analysis. METHODS The International Committee for Classification of Corneal Dystrophies (IC3D) was created to devise a current and accurate nomenclature. RESULTS This anatomic classification continues to organize dystrophies according to the level chiefly affected. Each dystrophy has a template summarizing genetic, clinical, and pathologic information. A category number from 1 through 4 is assigned, reflecting the level of evidence supporting the existence of a given dystrophy. The most defined dystrophies belong to category 1 (a well-defined corneal dystrophy in which a gene has been mapped and identified and specific mutations are known) and the least defined belong to category 4 (a suspected dystrophy where the clinical and genetic evidence is not yet convincing). The nomenclature may be updated over time as new information regarding the dystrophies becomes available. CONCLUSIONS The IC3D Classification of Corneal Dystrophies is a new classification system that incorporates many aspects of the traditional definitions of corneal dystrophies with new genetic, clinical, and pathologic information. Standardized templates provide key information that includes a level of evidence for there being a corneal dystrophy. The system is user-friendly and upgradeable and can be retrieved on the website www.corneasociety.org/ic3d.
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Affiliation(s)
- Jayne S Weiss
- Department of Ophthalmology, Kresge Eye Institute, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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