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Li W, Qu N, Li JK, Li YX, Han DM, Chen YX, Tian L, Shao K, Yang W, Wang ZS, Chen X, Jin XY, Wang ZW, Liang C, Qian WP, Wang LS, He W. Evaluation of the Genetic Variation Spectrum Related to Corneal Dystrophy in a Large Cohort. Front Cell Dev Biol 2021; 9:632946. [PMID: 33816482 PMCID: PMC8012530 DOI: 10.3389/fcell.2021.632946] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/02/2021] [Indexed: 11/13/2022] Open
Abstract
Aims To characterize the genetic landscape and mutation spectrum of patients with corneal dystrophies (CDs) in a large Han ethnic Chinese Cohort with inherited eye diseases (IEDs). Methods Retrospective study. A large IED cohort was recruited in this study, including 69 clinically diagnosed CD patients, as well as other types of eye diseases patients and healthy family members as controls. The 792 genes on the Target_Eye_792_V2 chip were used to screen all common IEDs in our studies, including 22 CD-related genes. Results We identified 2334 distinct high-quality variants on 22 CD-related genes in a large IEDs cohort. A total of 21 distinct pathogenic or likely pathogenic mutations were identified, and the remaining 2313 variants in our IED cohort had no evidence of CD-related pathogenicity. Overall, 81.16% (n = 56/69) of CD patients received definite molecular diagnoses, and transforming growth factor-beta-induced protein (TGFBI), CHTS6, and SLC4A11 genes covered 91.07, 7.14, and 1.79% of the diagnosed cases, respectively. Twelve distinct disease-associated mutations in the TGFBI gene were identified, 11 of which were previously reported and one is novel. Four of these TGFBI mutations (p.D123H, p.M502V, p.P501T, and p.P501A) were redefined as likely benign in our Han ethnic Chinese IED cohort after performing clinical variant interpretation. These four TGFBI mutations were detected in asymptomatic individuals but not in CD patients, especially the previously reported disease-causing mutation p.P501T. Among 56 CD patients with positive detected mutations, the recurrent TGFBI mutations were p.R124H, p.R555W, p.R124C, p.R555Q, and p.R124L, and the proportions were 32.14, 19.64, 14.29, 10.71, and 3.57%, respectively. Twelve distinct pathogenic or likely pathogenic mutations of CHTS6 were detected in 28 individuals. The recurrent mutations were p.Y358H, p.R140X, and p.R205W, and the proportions were 25.00, 21.43, and 14.29%, respectively. All individuals associated with TGFBI were missense mutations; 74.19% associated with CHTS6 mutations were missense mutations, and 25.81% were non-sense mutations. Hot regions were located in exons 4 and 12 of TGFBI individuals and located in exon 3 of CHTS6 individuals. No de novo mutations were identified. Conclusion For the first time, our large cohort study systematically described the variation spectrum of 22 CD-related genes and evaluated the frequency and pathogenicity of all 2334 distinct high-quality variants in our IED cohort. Our research will provide East Asia and other populations with baseline data from a Han ethnic population-specific level.
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Affiliation(s)
- Wei Li
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,Shenyang Industrial Technology Institute of Ophthalmology, Shenyang, China
| | - Ning Qu
- Department of Reproductive Medicine, Peking University Shenzhen Hospital, Shenzhen, China
| | - Jian-Kang Li
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Yu-Xin Li
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Basic Medicine, Qingdao University, Qingdao, China
| | - Dong-Ming Han
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Yi-Xi Chen
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, China
| | - Le Tian
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China.,School of Basic Medicine, Qingdao University, Qingdao, China
| | - Kang Shao
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Wen Yang
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Zhuo-Shi Wang
- Shenyang Industrial Technology Institute of Ophthalmology, Shenyang, China.,He Eye Specialists Hospital, He University, Shenyang, China
| | - Xuan Chen
- College of Plant Protection, Hunan Agricultural University, Changsha, China
| | - Xiao-Ying Jin
- College of Informatics, HuaZhong Agricultural University, Wuhan, China
| | - Zi-Wei Wang
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Chen Liang
- School of Basic Medicine, Qingdao University, Qingdao, China
| | - Wei-Ping Qian
- Department of Reproductive Medicine, Peking University Shenzhen Hospital, Shenzhen, China
| | - Lu-Sheng Wang
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Wei He
- Shenyang Industrial Technology Institute of Ophthalmology, Shenyang, China.,He Eye Specialists Hospital, He University, Shenyang, China
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2
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Bouyacoub Y, Falfoul Y, Ouederni M, Sayeb M, Chedli A, Chargui M, Sassi H, Chakroun Chenguel I, Munier FL, El Matri L, Abdelhak S, Cheour M. Granular type I corneal dystrophy in a large consanguineous Tunisian family with homozygous p.R124S mutation in the TGFBI gene. Ophthalmic Genet 2019; 40:329-337. [PMID: 31322463 DOI: 10.1080/13816810.2019.1639202] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Purpose: We report the clinical features and the mutational analysis in a large Tunisian family with granular corneal dystrophy type I (GCD1). Patients and Methods: Thirty-three members of the Tunisian family underwent a complete ophthalmologic examination. DNA extraction and direct Sanger sequencing of the exons 4 and 12 of transforming growth factor β Induced (TGFBI) gene was performed for 42 members. For the molecular modeling of TGFBI protein, we used pGenTHREADER method to identify templates, 3D-EXPRESSO program to align sequences, MODELLER to get a homology model for the FAS1 (fasciclin-like) domains and finally NOMAD-ref web server for the energy minimization. Results: The diagnosis of GCD1 was clinically and genetically confirmed. Sequencing of exon 4 of TGFBI gene revealed the p.[R124S] mutation at heterozygous and homozygous states in patients with different clinical severities. Visual acuity was severely affected in the homozygous patients leading to a first penetrating keratoplasty. Recurrence occurred rapidly, began in the seat of the corneal stitches and remained superficial up to 40 years after the graft. For heterozygous cases, visual acuity ranged from 6/10 to 10/10. Corneal opacities were deeper and predominating in the stromal center. According to bioinformatic analysis, this mutation likely perturbs the protein physicochemical properties and reduces its solubility without structural modification. Conclusions: Our study describes for the first time phenotype-genotype correlation in a large Tunisian family with GCDI and illustrates for the first time clinical and histopathological presentation of homozygous p.[R124S] mutation. These results help to understand pathophysiology of the disease.
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Affiliation(s)
- Yosra Bouyacoub
- Laboratory of Biomedical Genetics and Oncogenetics, Université Tunis El Manar, Institut Pasteur de Tunis, LR16IPT05 , Tunis , Tunisia.,Institut Supérieur de Biotechnologie, Université de Monastir , Monastir , Tunisia
| | - Yousra Falfoul
- B Department, Hedi Raies Institute of Ophthalmology , Tunis , Tunisia.,Oculogenetic Laboratory, LR14SP01, Hedi Raies Institute of Ophthalmology , Tunis , Tunisia
| | - Mariem Ouederni
- Department of Ophthalmology, Habib Thameur Hospital , Tunis , Tunisia
| | - Marwa Sayeb
- Laboratory of Biomedical Genetics and Oncogenetics, Université Tunis El Manar, Institut Pasteur de Tunis, LR16IPT05 , Tunis , Tunisia
| | - Aschraf Chedli
- Department of Anatomopathology, Habib Thameur Hospital , Tunis , Tunisia
| | - Mariem Chargui
- Laboratory of Biomedical Genetics and Oncogenetics, Université Tunis El Manar, Institut Pasteur de Tunis, LR16IPT05 , Tunis , Tunisia
| | - Hela Sassi
- Department of Ophthalmology, Habib Thameur Hospital , Tunis , Tunisia
| | | | - Francis L Munier
- Jules-Gonin Eye Hospital, University of Lausanne , Lausanne , Switzerland
| | - Leila El Matri
- B Department, Hedi Raies Institute of Ophthalmology , Tunis , Tunisia.,Oculogenetic Laboratory, LR14SP01, Hedi Raies Institute of Ophthalmology , Tunis , Tunisia
| | - Sonia Abdelhak
- Laboratory of Biomedical Genetics and Oncogenetics, Université Tunis El Manar, Institut Pasteur de Tunis, LR16IPT05 , Tunis , Tunisia
| | - Monia Cheour
- Department of Ophthalmology, Habib Thameur Hospital , Tunis , Tunisia
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3
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Clinical and genetic update of corneal dystrophies. Exp Eye Res 2019; 186:107715. [PMID: 31301286 DOI: 10.1016/j.exer.2019.107715] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/06/2019] [Accepted: 06/27/2019] [Indexed: 11/23/2022]
Abstract
The International Committee for Classification of Corneal Dystrophies (IC3D) distinguishes between 22 distinct forms of corneal dystrophy which are predominantly autosomal dominant, although autosomal recessive and X-chromosomal dominant patterns do exist. Before any genetic examination, there should be documentation of a detailed corneal exam of as many affected and unaffected family members as possible, because detailed phenotypic description is essential for accurate diagnosis. Corneal documentation should be performed in direct and indirect illumination at the slit lamp with the pharmacologically dilated pupil. For the majority of the corneal dystrophies, a phenotype-genotype correlation has not been demonstrated. However, for the dystrophies associated with mutations in the transforming growth factor, ß-induced gene (TGFBI) a general phenotype-genotype correlation is evident. The discovery of collagen, type XVII, alpha 1 mutation (COL17A1), causative in the called epithelial recurrent erosion dystrophy (ERED) was a very important step in the accurate diagnosis of corneal dystrophies. This led to the subsequent discovery that the entity previously called 10q Thiel-Behnke corneal dystrophy, was in reality actually COL17A1 ERED, and not Thiel-Behnke corneal dystrophy. In addition to the phenotypic landmarks, we describe the current genotype of the individual corneal dystrophies. Differential diagnosis can be aided by information on histopathology, optical coherence tomography (OCT), and confocal microscopy.
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4
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Kheir V, Cortés-González V, Zenteno JC, Schorderet DF. Mutation update: TGFBI pathogenic and likely pathogenic variants in corneal dystrophies. Hum Mutat 2019; 40:675-693. [PMID: 30830990 DOI: 10.1002/humu.23737] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 02/26/2019] [Accepted: 02/28/2019] [Indexed: 01/07/2023]
Abstract
Human transforming growth factor β-induced (TGFBI), is a gene responsible for various corneal dystrophies. TGFBI produces a protein called TGFBI, which is involved in cell adhesion and serves as a recognition sequence for integrins. An alteration in cell surface interactions could be the underlying cause for the progressive accumulation of extracellular deposits in different layers of the cornea with the resulting changes of refractive index and transparency. To this date, 69 different pathogenic or likely pathogenic variants in TGFBI have been identified in a heterozygous or homozygous state in various corneal dystrophies, including a novel variant reported here. All disease-associated variants were inherited as autosomal-dominant traits but one; this latter was inherited as an autosomal recessive trait. Most corneal dystrophy-associated variants are located at amino acids Arg124 and Arg555. To keep the list of corneal dystrophy-associated variant current, we generated a locus-specific database for TGFBI (http://databases.lovd.nl/shared/variants/TGFBI) containing all pathogenic and likely pathogenic variants reported so far. Non-disease-associated variants are described in specific databases, like gnomAD and ExAC but are not listed here. This article presents the most recent up-to-date list of disease-associated variants.
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Affiliation(s)
- Valeria Kheir
- Institute for Research in Ophthalmology, Sion, Switzerland.,Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Vianney Cortés-González
- Department of Genetics, Hospital "Dr. Luis Sanchez Bulnes", Asociación Para Evitar la Ceguera en México, Mexico City, Mexico
| | - Juan C Zenteno
- Department of Genetics, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico.,Department of Biochemistry, Faculty of Medicine, UNAM, Mexico City, Mexico
| | - Daniel F Schorderet
- Institute for Research in Ophthalmology, Sion, Switzerland.,Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland.,Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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5
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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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6
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pH Induced Conformational Transitions in the Transforming Growth Factor β-Induced Protein (TGFβIp) Associated Corneal Dystrophy Mutants. Sci Rep 2016; 6:23836. [PMID: 27030015 PMCID: PMC4814907 DOI: 10.1038/srep23836] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 02/12/2016] [Indexed: 11/24/2022] Open
Abstract
Most stromal corneal dystrophies are associated with aggregation and deposition of the mutated transforming growth factor-β induced protein (TGFβIp). The 4th_FAS1 domain of TGFβIp harbors ~80% of the mutations that forms amyloidogenic and non-amyloidogenic aggregates. To understand the mechanism of aggregation and the differences between the amyloidogenic and non-amyloidogenic phenotypes, we expressed the 4th_FAS1 domains of TGFβIp carrying the mutations R555W (non-amyloidogenic) and H572R (amyloidogenic) along with the wild-type (WT). R555W was more susceptible to acidic pH compared to H572R and displayed varying chemical stabilities with decreasing pH. Thermal denaturation studies at acidic pH showed that while WT did not undergo any conformational transition, the mutants exhibited a clear pH-dependent irreversible conversion from αβ conformation to β-sheet oligomers. The β-oligomers of both mutants were stable at physiological temperature and pH. Electron microscopy and dynamic light scattering studies showed that β-oligomers of H572R were larger compared to R555W. The β-oligomers of both mutants were cytotoxic to primary human corneal stromal fibroblast (pHCSF) cells. The β-oligomers of both mutants exhibit variations in their morphologies, sizes, thermal and chemical stabilities, aggregation patterns and cytotoxicities.
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7
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Pathogenesis and treatments of TGFBI corneal dystrophies. Prog Retin Eye Res 2015; 50:67-88. [PMID: 26612778 DOI: 10.1016/j.preteyeres.2015.11.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/12/2015] [Accepted: 11/16/2015] [Indexed: 11/22/2022]
Abstract
Transforming growth factor beta-induced (TGFBI) corneal dystrophies are a group of inherited progressive corneal diseases. Accumulation of transforming growth factor beta-induced protein (TGFBIp) is involved in the pathogenesis of TGFBI corneal dystrophies; however, the exact molecular mechanisms are not fully elucidated. In this review article, we summarize the current knowledge of TGFBI corneal dystrophies including clinical manifestations, epidemiology, most common and recently reported associated mutations for each disease, and treatment modalities. We review our current understanding of the molecular mechanisms of granular corneal dystrophy type 2 (GCD2) and studies of other TGFBI corneal dystrophies. In GCD2 corneal fibroblasts, alterations of morphological characteristics of corneal fibroblasts, increased susceptibility to intracellular oxidative stress, dysfunctional and fragmented mitochondria, defective autophagy, and alterations of cell cycle were observed. Other studies of mutated TGFBIp show changes in conformational structure, stability and proteolytic properties in lattice and granular corneal dystrophies. Future research should be directed toward elucidation of the biochemical mechanism of deposit formation, the relationship between the mutated TGFBIp and the other materials in the extracellular matrix, and the development of gene therapy and pharmaceutical agents.
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8
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Lang SJ, Eberwein P, Reinshagen H, Reinhard T, Sundmacher R. Simultaneous transplantation of limbal stem cells may reduce recurrences of granular dystrophy after corneal transplantation: 2 long-term case reports. Medicine (Baltimore) 2015; 94:e789. [PMID: 25997048 PMCID: PMC4602868 DOI: 10.1097/md.0000000000000789] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To present 2 cases with long-term relapse-free intervals only after limbo-keratoplasty but not after conventional penetrating keratoplasty in granular dystrophy.Retrospective review of the patient charts and photographs taken during long-term follow-up of 2 cases with granular dystrophy, in which 1 eye received penetrating keratoplasty and the fellow eye received penetrating limbo-keratoplasty.In the first patient, 1 eye showed extensive recurrence of granular deposits 17 years after penetrating keratoplasty was performed while in the second eye two-thirds of the corneal transplant adjacent to the transplanted limbal area remained clear 12 years after the limbo-corneal transplant. In the second patient, 1 eye showed no signs of recurrence 5 years after limbo-keratoplasty, whereas a recurrence of granular corneal deposits occurred 18 months after surgery in the fellow eye.These cases show that the simultaneous transplantation of healthy donor limbus when performing penetrating keratoplasty may prolong recurrence in granular corneal dystrophy. Although we were unable to prove it on the molecular level, these clinical courses may support the hypothesis that a limbal transplant helps prevent a recurrence.
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Affiliation(s)
- Stefan J Lang
- From the Eye Center, Albert-Ludwigs-University of Freiburg, Freiburg, Germany (TR, RS); Pallas Clinic Olten, Olten, Switzerland (SJL, PE)
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9
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Lakshminarayanan R, Chaurasia SS, Anandalakshmi V, Chai SM, Murugan E, Vithana EN, Beuerman RW, Mehta JS. Clinical and genetic aspects of the TGFBI-associated corneal dystrophies. Ocul Surf 2014; 12:234-51. [PMID: 25284770 DOI: 10.1016/j.jtos.2013.12.002] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 12/05/2013] [Accepted: 12/05/2013] [Indexed: 11/16/2022]
Abstract
Corneal dystrophies are a group of inherited disorders localized to various layers of the cornea that affect corneal transparency and visual acuity. The deposition of insoluble protein materials in the form of extracellular deposits or intracellular cysts is pathognomic. Mutations in TGFBI are responsible for superficial and stromal corneal dystrophies. The gene product, transforming growth factor β induced protein (TGFBIp) accumulates as insoluble deposits in various forms. The severity, clinicopathogenic variations, age of the onset, and location of the deposits depend on the type of amino acid alterations in the protein. Until 2006, 38 different pathogenic mutants were reported for the TGFBI-associated corneal dystrophies. This number has increased to 63 mutants, reported in more than 30 countries. There is no effective treatment to prevent, halt, or reverse the deposition of TGFBIp. This review presents a complete mutation update, classification of phenotypes, comprehensive reported incidents of various mutations, and current treatment options and their shortcomings. Future research directions and possible approaches to inhibiting disease progression are discussed.
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Affiliation(s)
- R Lakshminarayanan
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore
| | - Shyam S Chaurasia
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - Shu-Ming Chai
- Singapore Eye Research Institute, Singapore; Singapore National Eye Centre, Singapore
| | | | - Eranga N Vithana
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Roger W Beuerman
- Singapore Eye Research Institute, Singapore; SRP Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jodhbir S Mehta
- Singapore Eye Research Institute, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Singapore National Eye Centre, Singapore; Department of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore.
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Andreasen M, Nielsen SB, Runager K, Christiansen G, Nielsen NC, Enghild JJ, Otzen DE. Polymorphic fibrillation of the destabilized fourth fasciclin-1 domain mutant A546T of the Transforming growth factor-β-induced protein (TGFBIp) occurs through multiple pathways with different oligomeric intermediates. J Biol Chem 2012; 287:34730-42. [PMID: 22893702 DOI: 10.1074/jbc.m112.379552] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the transforming growth factor β-induced protein (TGFBIp) are linked to the development of corneal dystrophies in which abnormal protein deposition in the cornea leads to a loss of corneal transparency and ultimately blindness. Different mutations give rise to phenotypically distinct corneal dystrophies. Most mutations are located in the fourth fasciclin-1 domain (FAS1-4). The amino acid substitution A546T in the FAS1-4 domain is linked to the development of lattice corneal dystrophy with amyloid deposits in the superficial and deep stroma, classifying it as an amyloid disease. Here we provide a detailed description of the fibrillation of the isolated FAS1-4 domain carrying the A546T substitution. The A546T substitution leads to a significant destabilization of FAS1-4 and induces a partially folded structure with increased surface exposure of hydrophobic patches. The mutation also leads to two distinct fibril morphologies. Long straight fibrils composed of pure β-sheet structure are formed at lower concentrations, whereas short and curly fibrils containing a mixture of α-helical and β-sheet structures are formed at higher concentrations. The formation of short and curly fibrils is preceded by the formation of a small number of oligomeric species with high membrane permeabilization potential and rapid fibril formation. The long straight fibrils are formed more slowly and through progressively bigger oligomers that lose their membrane permeabilization potential as fibrillation proceeds beyond the lag phase. These different fibril classes and associated biochemical differences may lead to different clinical symptoms associated with the mutation.
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Affiliation(s)
- Maria Andreasen
- Center for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience Center (iNANO) and Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus, Denmark
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11
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Long Y, Gu YS, Han W, Li XY, Yu P, Qi M. Genotype-phenotype correlations in Chinese patients with TGFBI gene-linked corneal dystrophy. J Zhejiang Univ Sci B 2011; 12:287-92. [PMID: 21462384 DOI: 10.1631/jzus.b1000154] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In this paper, we report the clinical and molecular features of the distinct TGFBI (human transforming growth factor β-induced, OMIM No. 601692) gene-linked corneal dystrophy. Altogether, five pedigrees and ten unrelated individuals diagnosed as corneal dystrophy were recruited. Peripheral venous DNA was extracted, and then amplified by polymerase chain reaction (PCR) and scanned for mutation by single-stranded conformation polymorphism (SSCP). Direct DNA sequencing was used to analyze the mutations of the TGFBI gene. In our study, thirty patients from five pedigrees and ten sporadic patients were diagnosed as four TGFBI gene-linked corneal dystrophies of granular corneal dystrophy type I (GGCD I), Avellino corneal dystrophy (ACD), lattice corneal dystrophy type I (LCD I), and lattice corneal dystrophy type IIIA (LCD IIIA), and in total, seven disease-causing mutations, namely R555W, A546D, A546T, and T538P mutations in exon 12, R124H and R124C mutations in exon 4, and P501T mutation in exon 11, were identified, while four polymorphisms of V327V, L472L, F540F, and 1665-1666insC were screened in exons 8, 11, and 12. The study ascertained the tight genotype-phenotype relationship and confirmed the clinical and genetic features of four TGFBI gene-linked corneal dystrophies.
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Affiliation(s)
- Yan Long
- Department of Ophthalmology, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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12
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Dalton K, Schneider S, Sorbara L, Jones L. Confocal microscopy and optical coherence tomography imaging of hereditary granular dystrophy. Cont Lens Anterior Eye 2009; 33:33-40. [PMID: 19945908 DOI: 10.1016/j.clae.2009.09.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 09/26/2009] [Accepted: 09/30/2009] [Indexed: 10/20/2022]
Abstract
OBJECTIVES This case report examines the clinical characteristics of hereditary granular dystrophy through the use of slit lamp digital photography, confocal microscopy (CM) and optical coherence tomography (OCT). A review of the literature describing the histopathological and genetic associations of stromal dystrophies, suggest it may be possible to differentiate dystrophies based on their clinical manifestations, and appearances of CM and OCT images, with or without the use of genetic testing. CASE REPORT Two sisters, previously diagnosed with Granular (Groenouw I) Dystrophy, were examined. Examination included the use of digital slit lamp photography, CM and OCT imaging. RESULTS "Breadcrumb" opacities were visualized in the anterior two-thirds of the stroma with all three imaging techniques. Opacities were demonstrated in the posterior third of the stroma with the digital photography and OCT techniques. CONCLUSIONS The digital photography, CM and OCT images support the sister's diagnosis of Granular (Groenouw I) Dystrophy. Currently, genetic and histopathological testing are the only techniques available to determine exactly which corneal dystrophy and gene mutation are present. The results of this case report demonstrate that slit lamp digital photography, combined with CM and OCT may be capable of providing sufficient diagnostic information to diagnose corneal granular dystrophies in a clinical setting.
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Affiliation(s)
- Kristine Dalton
- School of Optometry, University of Waterloo, Ontario, Canada.
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13
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Karring H, Runager K, Valnickova Z, Thøgersen IB, Møller-Pedersen T, Klintworth GK, Enghild JJ. Differential expression and processing of transforming growth factor beta induced protein (TGFBIp) in the normal human cornea during postnatal development and aging. Exp Eye Res 2009; 90:57-62. [PMID: 19788893 DOI: 10.1016/j.exer.2009.09.011] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 09/07/2009] [Accepted: 09/13/2009] [Indexed: 11/17/2022]
Abstract
Transforming growth factor beta induced protein (TGFBIp, also named keratoepithelin) is an extracellular matrix protein abundant in the cornea. The purpose of this study was to determine the expression and processing of TGFBIp in the normal human cornea during postnatal development and aging. TGFBIp in corneas from individuals ranging from six months to 86 years of age was detected and quantified by immunoblotting. The level of TGFBIp in the cornea increases about 30% between 6 and 14 years of age, and adult corneas contain 0.7-0.8 microg TGFBIp per mg wet tissue. Two-dimensional (2-D) immunoblots of the corneal extracts showed a characteristic "zig-zag" pattern formed by different lower-molecular mass TGFBIp isoforms (30-60 kDa). However, the relative abundance of the different isoforms was different between infant corneas (<1 year) and the child/adult corneas (>6 years). Matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) data of TGFBIp isoforms separated on large 2-D gels show that TGFBIp is proteolytically processed from the N-terminus. This observation was supported by in silico 2-D gel electrophoresis showing that sequential proteolytical trimming events from the N-terminus of mature TGFBIp generate TGFBIp isoforms which form a similar "zig-zag" pattern when separated by 2-D polyacrylamide gel electrophoresis (PAGE). This study shows that in humans TGFBIp is more abundant in mature corneas than in the developing cornea and that the processing of TGFBIp changes during postnatal development of the cornea. In addition, TGFBIp appears to be degraded in a highly orchestrated manner in the normal human cornea with the resulting C-terminal fragments being retained in the cornea. The age-related changes in the expression and processing of corneal TGFBIp suggests that TGFBIp may play a role in the postnatal development and maturation of the cornea. Furthermore, these observations may be relevant to the age at which mutant TGFBIp deposits in the cornea in those dystrophies caused by mutations in the transforming growth factor beta induced gene (TGFBI) as well as the mechanisms of corneal protein deposition.
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Affiliation(s)
- Henrik Karring
- Institute of Chemical Engineering, Biotechnology and Environmental Technology, Faculty of Engineering, University of Southern Denmark, Niels Bohrs Allé 1, DK-5230 Odense M, Denmark
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Yu P, Gu Y, Jin F, Hu R, Chen L, Yan X, Yang Y, Qi M. p.Ala546 > Asp and p.Arg555 > Trp mutations of TGFBI gene and their clinical manifestations in two large Chinese families with granular corneal dystrophy type I. ACTA ACUST UNITED AC 2008; 12:421-5. [PMID: 18752451 DOI: 10.1089/gte.2008.0005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The aim of this study was to conduct clinical, genetic, and molecular analysis of Chinese patients with granular corneal dystrophy type I (CDGG1). Two large unrelated Chinese families with CDGG1 were clinically and genetically evaluated. Molecular genetic analysis was performed on DNA extracted from peripheral blood. Exons 4, 11, 12, and 14 of the human transforming growth factor beta-induced gene (TGFBI, formerly designated BIGH3) were amplified by PCR, scanned for mutations using the single-strand conformation polymorphism method, and the mutations identified by nucleotide sequencing. One family segregated the p.Ala546 > Asp mutation, and the other family had a p.Arg555 > Trp mutation. These missense mutations were not found in 53 unrelated, healthy individuals analyzed as controls. Clinical and genetic evaluations revealed the variable severity, symmetry, and age of onset in visual impairment in these families for different mutations. Penetrance of visual impairment in these families was 100% and 75%, respectively. This study confirms that the p.Arg555 > Trp mutation is a frequent cause of CDGG1, and that the p.Ala546 > Asp mutation is also associated with this disease.
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Affiliation(s)
- Ping Yu
- Department of Medical Genetics, School of Medicine, Zhejiang University, Hangzhou, People's Republic of China
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15
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Pampukha VN, Kravchenko SA, Tereshchenko F, Drozhzhina GI, Livshits LA. TGFBI gene mutations in the Ukrainian patients with inherited corneal stromal dystrophies. RUSS J GENET+ 2008. [DOI: 10.1134/s1022795408100104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Moon JW, Kim SW, Kim TI, Cristol SM, Chung ES, Kim EK. Homozygous granular corneal dystrophy type II (Avellino corneal dystrophy): natural history and progression after treatment. Cornea 2008; 26:1095-100. [PMID: 17893542 DOI: 10.1097/ico.0b013e3181484013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To describe the clinical features of homozygous granular corneal dystrophy type II (GCDII) with age and with several kinds of treatment in 18 homozygous patients in several different conditions. METHODS Eighteen homozygous GCDII patients, confirmed with DNA analysis, of 13 families were enrolled. Their clinical features that include age at detection by parents, visual acuity, and disease progression were evaluated. We also studied the recurrence patterns for the 13 patients who underwent phototherapeutic keratectomy, penetrating keratoplasty, lamellar keratoplasty, or deep lamellar keratoplasty. RESULTS The age at detection by the parents ranged from 3 to 5 years; visual loss begins in childhood with progression into the 20s. All of the patients who had undergone surgeries acquired better vision immediately after surgery. Corneal deposits reappeared soon after treatments. Recurrences became progressively more rapid and severe with treatments. CONCLUSIONS The clinical features of homozygous GCDII are characterized by a severe granular type of corneal dystrophy with an early onset and rapid progression. After surgical treatment, recurrence is rapid and severe.
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Affiliation(s)
- Jong Wook Moon
- Corneal Dystrophy Research Institute, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea
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17
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Abstract
The lattice corneal dystrophies (LCD) and granular corneal dystrophies (GCD) are autosomal dominant disorders of the corneal stroma. They are bilateral, progressive conditions characterized by the formation of opacities arising due to the deposition of insoluble material in the corneal stroma leading to visual impairment. The LCDs and GCDs are distinguished from each other and are divided into subtypes on the basis of the clinical appearance of the opacities, clinical features of the disease, and on histopathological staining properties of the deposits. The GCDs and most types of LCD arise from mutations in the transforming growth factor beta-induced (TGFBI) gene on chromosome 5q31. Over 30 mutations causing LCD and GCD have been identified so far in the TGFBI. There are two mutation hotspots corresponding to arginine residues at positions 124 and 555 of the transforming growth factor beta induced protein (TGFBIp) and they are the most frequent sites of mutation in various populations. Mutations at either of these two hotspots result in specific types of LCD or GCD. The majority of identified mutations involve residues in the fourth fasciclin-like domain of TGFBIp.
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Affiliation(s)
- Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, L.V. Prasad Eye Institute, Hyderabad, India.
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18
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Yamada N, Chikama TI, Morishige N, Yanai R, Nishida T, Inui M, Seki K. Homozygous mutation (L527R) of TGFBI in an individual with lattice corneal dystrophy. Br J Ophthalmol 2005; 89:771-3. [PMID: 15923518 PMCID: PMC1772697 DOI: 10.1136/bjo.2004.056168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Sjoberg SA. Genetics of Corneal Disease for the Ocular Surface Clinician. Ocul Surf 2005; 3:155-66. [PMID: 17131020 DOI: 10.1016/s1542-0124(12)70197-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Advances in the understanding of inherited corneal and external diseases may allow interventions that prevent the substantial vision impairment currently caused by these diseases. The observant clinician may first recognize inherited corneal and external diseases based on clinical examination and a careful family history. Researchers using positional cloning and candidate gene techniques have identified several disease-causing genes. Identification of the genes responsible for inherited corneal and external diseases will lead to more definitive diagnoses and represent the first step in development of effective therapies. Future endeavors are directed toward identifying additional inherited corneal and external diseases, the genes that cause them, and possible gene therapies to improve visual outcomes.
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Affiliation(s)
- Stacy A Sjoberg
- Department of Ophthalmology, University of Iowa Hospitals and Clinics, Iowa City, IA 52242, USA.
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Aldave AJ, Gutmark JG, Yellore VS, Affeldt JA, Meallet MA, Udar N, Rao NA, Small KW, Klintworth GK. Lattice corneal dystrophy associated with the Ala546Asp and Pro551Gln missense changes in the TGFBI gene. Am J Ophthalmol 2004; 138:772-81. [PMID: 15531312 DOI: 10.1016/j.ajo.2004.06.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2004] [Indexed: 11/16/2022]
Abstract
PURPOSE To report a phenotypic variant of lattice corneal dystrophy associated with two missense changes, Ala546Asp and Pro551Gln, in the transforming growth factor-beta-induced gene (TGFBI). DESIGN Experimental study. METHODS Genomic DNA was obtained from the proband as well as affected and unaffected family members. Exons 4, 11, 12, and 14 of the TGFBI gene were amplified and sequenced. Additionally, a corneal button excised from the proband was examined by light and transmission electron microscopy. Haplotype analysis was performed on the proband's family and members of a previously identified pedigree with the same TGFBI gene missense changes. RESULTS Bilateral, symmetric, radially arranged, branching refractile lines within and surrounding an area of central anterior stromal haze were noted in the proband. Multiple polymorphic, refractile deposits were noted in the mid and posterior stroma in both the proband and her daughter. Light and electron microscopic analyses demonstrated amyloid and excluded the presence of deposits characteristic of granular corneal dystrophy. Screening of TGFBI exon 12 in the proband and her affected daughter revealed two missense changes, Ala546Asp and Pro551Gln (both absent in 250 control chromosomes). Haplotype analysis suggested that the mutations in this family and in a previously identified pedigree reflect a founder effect, rather than an independent occurrence. CONCLUSIONS We present a phenotypic variant of lattice corneal dystrophy associated with the Ala546Asp and Pro551Gln missense changes in exon 12 of the TGFBI gene. A common ancestor appears to account for the missense mutations observed in this pedigree and in a previously reported family.
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Affiliation(s)
- Anthony J Aldave
- Cornea Service, The Jules Stein Eye Institute, 100 Stein Plaza, Los Angeles, CA 90095, USA.
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21
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Schmitt-Bernard CF, Pouliquen Y, Argilès A. [BIG-H3 protein: mutation of codon 124 and corneal amyloidosis]. J Fr Ophtalmol 2004; 27:510-22. [PMID: 15179309 DOI: 10.1016/s0181-5512(04)96173-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In 1997, a group of hereditary corneal dystrophies was related to mutations in the TGFBI (BIGH3) gene. Within this group, some corneal dystrophies present particular biochemical features in that they are characterized by corneal amyloid deposition. Contrary to clinical and genetic knowledge, the biochemical characteristics of the encoded protein (Big-h3) and the mechanisms of its amyloid conversion remain unclear. We review the current knowledge on the Big-h3 protein and focus on the behavior of the codon 124 region. We discuss this protein's mechanisms of amyloid conversion from our results and previous reports as well as from other types of amyloidosis. These data provide a better understanding of the putative processes leading to the phenotypic variations linked with their respective codon 124 mutation.
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22
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Abstract
Modern molecular genetics has had a profound effect on our understanding of corneal dystrophies. Mutations in the BIGH3 gene are responsible for four autosomal dominant corneal dystrophies. The mutation spectrum reveals the phenotypically diverse possibilities stemming from mutations of a single gene. Dystrophies have been grouped together in a "stamp-collector" fashion. Classification has been based on clinical description of disease. With better appreciation of molecular genetics, classifications can be based on underlying genetic cause. In fact, classification schema based on the gene or molecular defect responsible for the dystrophy have been introduced. Different phenotypes are determined by different genotypes. Clinicians must become more adept at understanding the molecular genetics of corneal dystrophies as genetics is increasingly important in the long-term diagnostic and therapeutic approach to dystrophies.
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Affiliation(s)
- Nouman Siddiqui
- Duke University Eye Center, Duke University Medical Center, Durham, North Carolina, USA
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Inoue T, Watanabe H, Yamamoto S, Maeda N, Inoue Y, Shimomura Y, Tano Y. Recurrence of corneal dystrophy resulting from an R124H Big-h3 mutation after phototherapeutic keratectomy. Cornea 2002; 21:570-3. [PMID: 12131032 DOI: 10.1097/00003226-200208000-00007] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE The purpose of the study was to investigate the recurrence-free interval after phototherapeutic keratectomy (PTK) in patients with corneal dystrophies resulting from an Arg124His (R124H) mutation of the Big-h3 gene. METHODS Patients with corneal dystrophy resulting from a genetically confirmed Big-h3 R124H mutation were examined with a slit lamp. The patients were divided into two groups on the basis of the mutation genotype, and the recurrence-free interval was analyzed. RESULTS In the 4 eyes of 3 homozygous patients, the mean (+/- standard deviation [SD]) recurrence-free interval was 9.5 +/- 3.1 months, whereas in the 7 eyes of 4 heterozygous patients it was 38.4 +/- 6.2 months. The former interval was statistically shorter than the latter (Kaplan-Meier survival analysis with log-rank test, p = 0.004). CONCLUSIONS These results strongly suggest that the mutation genotype of Big-h3 gene determined the recurrence-free interval as well as the clinical picture after PTK. Therefore, PTK should be considered for patients with Big-h3 R124H corneal dystrophy, on the basis of the expected recurrence-free interval deduced from molecular analysis of the zygosity of the Big-h3 R124H mutation.
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Affiliation(s)
- Tomoyuki Inoue
- Department of Ophthalmology, Osaka University Medical School E-7, 2-2 Yamadaoka, Suita 565-0871, Osaka, Japan
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Schmitt-Bernard CF, Schneider C, Argilés A. Clinical, histopathologic, and ultrastructural characteristics of BIGH3(TGFBI) amyloid corneal dystrophies are supportive of the existence of a new type of LCD: the LCDi. Cornea 2002; 21:463-8. [PMID: 12072720 DOI: 10.1097/00003226-200207000-00006] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To assess the morphologic differences of three types of lattice corneal dystrophies (LCDs) from histologic, immunohistochemical, and ultrastructural studies. METHODS Corneas from three patients, one LCD1, one His626Arg-LCD, and one LCD3A were processed for Congo red, betaig-h3(541-564) antibodies immunostaining, and electron transmission microscopy studies. Control tissues were submitted to identical analyses and consisted of one cornea from a patient not having LCD and one skin biopsy from the patient suffering from LCD1. RESULTS The three corneas displayed birefringent congophilic deposits under polarized light, confirming their amyloid nature. The deposits differed regarding their shape and location in each of the corneas. A strong immunoreactivity for betaig-h3 was shown in the LCD1 and His626Arg-LCD deposits, which was faint for the LCD3A deposits. Ultrastructural analysis confirmed the dissimilarity of the deposits among the different types of LCD. No amyloid deposits were observed in the skin from the LCD1 patient, whereas immunostaining showed the presence of high amounts of betaig-h3. CONCLUSION Our results show that betaig-h3 is involved in amyloid deposition in all the LCDs included in the study (LCD1, His626Arg-LCD, and LCD3A). These three forms of LCD, clinically different, were also distinguishable histologically, confirming that they belong to distinctive groups of LCDs. The absence of amyloid deposition in skin from the LCD1 patient supports cornea-specific amyloid formation. In light of the present clinical, histologic, and ultrastructural data, His626Arg and related LCDs constitute a separate group of LCD that could be considered as of intermediate type on clinical grounds.
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Affiliation(s)
- Clair-Florent Schmitt-Bernard
- Institut de Génétique Humaine, CNRS UPR 1142, Antigone Ophtalmologie, 141 Rue de la Cardonille, 34396 Montpellier Cedex 5, France.
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Kiratli H, Irkeç M, Ozgül K, Ogüş A. The phenotype of arg555trp mutation in a large Turkish family with corneal granular dystrophy. Eur J Ophthalmol 2001; 11:333-7. [PMID: 11820303 DOI: 10.1177/112067210101100403] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
PURPOSE A large Turkish family with 52 members, 26 of whom had Groenouw type 1 corneal granular dystrophy was evaluated by genetic linkage studies and mutation analyses. Phenotype-genotype correlations were also assessed. METHODS DNA from peripheral blood lymphocytes of 22 family members was used in establishing linkage to chromosome 5q31. Single-strand conformation polymorphism analysis was done to detect mutations in exons 4 and 12 of the human transforming growth factor beta-induced gene located on chromosome 5q31. Automated sequencing was performed on exon 12 of an affected patient. RESULTS Patients yonger than 15 years of age had typical linear, granular opacities whereas adults had coarser, deeper granular stromal deposits. These changes were not associated with recurrent erosions or significant visual disabilities. The family was linked to chromosome 5q31 and a DNA shift was observed on exon 12 of affected patients. CGG to TGG transition producing R555W mutation was found. CONCLUSIONS Segregation of Arg555Trp has been described as causing Groenouw type I corneal dystrophy of variable severity in patients of various ethnic backgrounds. In this large Turkish pedigree, the Arg555Trp mutation was associated with a mild phenotype that became clinically evident at five years of age but which remained asymptomatic in terms of corneal erosions.
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Affiliation(s)
- H Kiratli
- Department of Ophthalmology, School of Medicine, Hacettepe University, Ankara, Turkey.
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Kinoshita S, Adachi W, Sotozono C, Nishida K, Yokoi N, Quantock AJ, Okubo K. Characteristics of the human ocular surface epithelium. Prog Retin Eye Res 2001; 20:639-73. [PMID: 11470454 DOI: 10.1016/s1350-9462(01)00007-6] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
An appreciation of the biological characteristics of the human ocular surface epithelium affords us a great insight into the physiology of the human ocular surface in health and disease. Here, we review five important aspects of the human ocular surface epithelium. First, we recognize the discovery of corneal epithelial stem cells, and note how the palisades of Vogt have been suggested as a clinical marker of their presence. Second, we introduce the concept of the gene expression profile of the ocular surface epithelium as arrived at using a new strategy for the systematic analysis of active genes. We also provide a summary of several genes abundantly or uniquely expressed in the human corneal epithelium, namely clusterin, keratin 3, keratin 12, aldehyde dehydrogenase 3 (ALDH3), troponin-I fast-twitch isoform, ssig-h3, cathepsin L2 (cathepsin V), uroplakin Ib, and Ca(2+)-activated chloride channel. Genes related to limbal and conjunctival epithelia are also described. Third, we touch upon the genetic abnormalities thought to be involved with epithelial dysfunction in Meesmann's dystrophy, gelatinous drop-like corneal dystrophy, and the ssig-h3-mutated corneal dystrophies. Fourth, we provide an update regarding the current state of knowledge of the role of cytokines, growth factors and apoptosis in relation to ocular surface homeostasis and tissue reconstruction; the main factors being epidermal growth factor (EGF), keratinocyte growth factor (KGF), hepatocyte growth factor (HGF), transforming growth factor-ss (TGF-ss), and some inflammatory cytokines. Fifth, corneal epithelial barrier function and dysfunction as measured by fluorophotometry is remarked upon, with an explanation of the FL-500 fluorophotometer and its ability to detect corneal epithelial dysfunction at a subclinical level. The research described in this review has undoubtedly generated a complete understanding of corneal epithelial pathophysiology-an understanding that, directly or indirectly, has helped advance the development of new therapeutic modalities for ocular surface reconstruction.
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Affiliation(s)
- S Kinoshita
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 645 Kajii-cho, Hirokoji Kawaramachi, Kamigyo-ku, Kyoto 602-0841, Japan.
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Dighiero P, Niel F, Ellies P, D'Hermies F, Savoldelli M, Renard G, Delpech M, Valleix S. Histologic phenotype-genotype correlation of corneal dystrophies associated with eight distinct mutations in the TGFBI gene. Ophthalmology 2001; 108:818-23. [PMID: 11297504 DOI: 10.1016/s0161-6420(00)00662-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To establish a phenotype-genotype correlation of various autosomal-dominant corneal dystrophies among French subjects. DESIGN Retrospective molecular genetic study and clinicopathologic correlation. PARTICIPANTS Forty-four subjects from 26 unrelated French families were included in this study, and 60 corneal buttons could be examined at the histologic and ultrastructural levels. METHODS Light microscopy and transmission electron microscopy were performed on corneal specimens obtained during keratoplasty. Blood samples were collected for DNA analysis. MAIN OUTCOME MEASURES After genomic DNA extraction from peripheral blood leukocytes of each family member, exons of the TGFBI gene were amplified by polymerase chain reaction (PCR), and the PCR products were directly sequenced on both strands. RESULTS Four different mutations were found to be responsible for dystrophy of granular type (R555W, R124L, R124H, and R124L+delT125-delE126), three other different mutations produced a lattice type (R124C, H626R, and A546T), and the last mutation identified was associated with the honeycomb-shaped dystrophy (R555Q). Each subtype of dystrophy showed, histologically and ultrastructurally, specific characteristics that are easily recognizable. However, besides these stereotyped forms, differential histologic diagnosis of atypical forms remains difficult, and these forms could be misdiagnosed. CONCLUSIONS The characteristic biomicroscopic appearance and histopathologic features of each "classic" dystrophy present a significant degree of specificity and generally provide an accurate diagnosis. However, atypical forms in which clinical and histologic data alone could be misleading, are unequivocally diagnosed after DNA analysis.
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Affiliation(s)
- P Dighiero
- Department of Ophthalmology, Hôtel-Dieu Hospital, Paris, France
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Kocak-Altintas AG, Kocak-Midillioglu I, Akarsu AN, Duman S. BIGH3 gene analysis in the differential diagnosis of corneal dystrophies. Cornea 2001; 20:64-8. [PMID: 11189007 DOI: 10.1097/00003226-200101000-00013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To identify the mutation in the keratoepithelin gene for proper diagnosis of granular corneal dystrophies. METHODS Four generations of a single family with corneal dystrophy were analyzed. Fourteen family members were examined and 11 were found to be affected by clinical evaluation. Genetic DNA was extracted from proband's leukocytes for molecular analysis. Exons 4 and 12 of the BIGH3 gene were amplified then directly sequenced. RESULTS The clinical appearance of corneas consisted of grayish white granules with sharp borders, fine dots, and radial lines in the superficial part of the central corneal stroma, which resembles granular and Avellino corneal dystrophies. Performing BIGH3 gene analysis, we observed a C-to-T transition at position 1710 (CGG to TGG) producing R555W mutation, which is a hot spot for granular corneal dystrophy. CONCLUSION Direct clinical examination may be insignificant in the proper diagnosis of corneal dystrophies, and molecular genetic approach may be required.
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Affiliation(s)
- A G Kocak-Altintas
- SB Ankara Training and Research Hospital, Hacettepe University Institute of Child Health, Ankara, Turkey.
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Fujiki K, Hotta Y, Nakayasu K, Yamaguchi T, Kato T, Uesugi Y, Ha NT, Endo S, Ishida N, Lu WN, Kanai A. Six different mutations of TGFBI (betaig-h3, keratoepithelin) gene found in Japanese corneal dystrophies. Cornea 2000; 19:842-5. [PMID: 11095060 DOI: 10.1097/00003226-200011000-00015] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE To investigate mutations of the human transforming growth factor beta-induced gene (TGFBI), transforming growth factor-beta-induced gene product (betaig-h3, keratoepithelin), in Japanese patients with Avellino corneal dystrophy (ACD), lattice corneal dystrophy (LCD), granular corneal dystrophy (GCD), and Reis-Bücklers corneal dystrophy (RBCD). METHODS Genomic DNA was extracted from the peripheral blood of 75 patients and 7 unaffected relatives from 60 families with ACD, 34 patients and 8 unaffected relatives from 21 families with LCD, 4 patients and 4 unaffected relatives from 4 families with GCD, and 4 patients and an unaffected relative from 3 families with RBCD. Fifty normal volunteers served as controls. Exons 4, 11, and 12 of the TGFBI gene were amplified by polymerase chain reaction and were directly sequenced. RESULTS Six different heterozygous missense mutations were detected in codons R124, L518, L527, and R555 of the TGFBI gene in the 117 patients from 88 families. A R124H mutation was detected in the patients with ACD. A R124C mutation was detected in the patients with LCD type 1 (LCD1), L518P was in atypical LCDI, and L527R in LCD with opacities deep in stroma. A R555W mutation was detected in the patients with GCD. A R555Q mutation was detected in the patients with RBCD. CONCLUSIONS We conclude that codons R124 and R555 of the TGFBI gene are also hot spots in Japanese patients with ACD, LCD, GCD, and RBCD. Many Japanese patients with CD had ACD with R124H mutation. GCD with R555W mutation was rare.
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Affiliation(s)
- K Fujiki
- Department of Ophthalmology, Juntendo University School of Medicine, Tokyo, Japan
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Abstract
PURPOSE To indicate important changes in our understanding of the corneal dystrophies. METHODS A review of the literature of the last quarter of a century. RESULTS The earliest clinical classifications of the corneal dystrophies were based on the application of clinical, biological, histochemical, and ultrastructural methods. Since then, the first great impetus to our understanding has come from the application of techniques to map disorders to specific chromosome loci, using polymorphic markers. More recently, using candidate gene and related approaches, it has been possible to identify genes causing several of the corneal dystrophies and the mutations responsible for their phenotypic variation. A notable success has been to show that several important "stromal" dystrophies result from mutations in the gene beta ig-h3, which encodes for the protein keratoepithelin (beta ig-h3). CONCLUSIONS For the corneal dystrophies, as with other inherited disorders, there is room for two sorts of classification system, one based mainly on clinical presentation and the other on an up-to-date understanding of the genetic mechanisms. They are not mutually exclusive. Some developmental corneal disorders are also discussed.
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Affiliation(s)
- A J Bron
- Nuffield Laboratory of Ophthalmology, University of Oxford, UK
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Kaji Y, Amano S, Oshika T, Usui T, Kitagawa M, Mimura T, Matsubara M. Chronic clinical course of two patients with severe corneal dystrophy caused by homozygous R124H mutations in the betaig-h3 gene. Am J Ophthalmol 2000; 129:663-5. [PMID: 10844061 DOI: 10.1016/s0002-9394(00)00372-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To report the chronic clinical course of two patients with homozygous R124H mutations in the betaig-h3 gene. METHODS Case reports. RESULTS Two patients with homozygous R124H mutations in the betaig-h3 gene developed severe juvenile corneal opacities that required keratoplasty. After surgery, corneal opacities recurred and limited the recovery of visual acuity in the chronic follow-up. CONCLUSION In patients with homozygous R124H mutations in the betaig-h3 gene, recurrence of corneal opacities after keratoplasty limits the recovery of visual acuity in the chronic follow-up.
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Affiliation(s)
- Y Kaji
- Department of Ophthalmology, University of Tokyo School of Medicine, Tokyo, Japan
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Abstract
PURPOSE To improve our understanding of the role of specific genes on corneal transparency through a review of linkage to specific chromosomal loci and the identification of the mutant genes dealing with the corneal dystrophies. METHOD Relevant recent literature on the corneal dystrophies is reviewed. RESULTS Molecular genetic studies of the corneal dystrophies suggest that genes on at least 10 human chromosomes are involved in the maintenance of corneal transparency (chromosomes 1, 5, 9, 10, 12, 16, 17, 20, 21, and X). Within the 10 chromosomes to which corneal dystrophies have been mapped, specific genetic mutations in seven genes (GSN, BIGH3, KRT3, See also pp. 687-691. KRT12, MSS1, GLA, and ARSC1) have been identified in 15 corneal dystrophies. Some corneal dystrophies that are considered distinct clinicopathologic entities are actually caused by different mutations in the same gene. For example, lattice dystrophy types I and IIIA, granular corneal dystrophy types I, II (Avellino dystrophy), and III (Reis-Bucklers dystrophy), and Thiel-Behnke corneal dystrophy are the result of mutations in BIGH3. Mutations in three genes (GSN, BIGH3, MSS1) are associated with amyloid deposition in the cornea. A gene for keratoconus has been mapped to chromosome 21, which is noteworthy because of the established association of keratoconus in Down syndrome (trisomy 21). CONCLUSION Recent genetic studies on the corneal dystrophies provide insight into some of these disorders at a basic molecular level. Some corneal dystrophies that were previously believed to be distinct clinicopathologic entities are closely related at the molecular level with the different phenotypes resulting from distinct mutations in the same gene. This new knowledge is leading to a revised classification of the corneal dystrophies and to the development of animal models of corneal dystrophies. The latter will lead to a better understanding of the pathogenesis of the disorders and hence to novel therapeutic approaches to those dystrophies that cause significant visual impairment. Research of this nature is only in its infancy.
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Affiliation(s)
- G K Klintworth
- Department of Pathology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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Gupta SK, Hodge WG. A new clinical perspective of corneal dystrophies through molecular genetics. Curr Opin Ophthalmol 1999; 10:234-41. [PMID: 10621529 DOI: 10.1097/00055735-199908000-00003] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
In the past 2 years, significant advances have been made in the genetics of corneal dystrophies. Genetic heterogeneity (one disease condition caused by single mutations in any one of multiple genes) and phenotypic diversity (many disease conditions caused by mutations in a single gene) are common emerging themes. Genetic heterogeneity in Meesmann corneal dystrophy was established with the identification of two causative genes, keratins 3 and 12, that encode cytoskeletal proteins. Conversely, mutations in a single gene, keratoepithelin, were found to cause several distinct corneal dystrophies affecting the Bowman layer and the stroma. We present a novel preliminary classification of corneal dystrophies based on molecular etiology. This classification may be useful in understanding the pathogenesis of corneal dystrophies and in developing new strategies to treat these dystrophies.
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Affiliation(s)
- S K Gupta
- University of Ottawa Eye Institute, Ontario, Canada
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