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Han SB, Anandalakshmi V, Wong CW, Ng SR, Mehta JS. Genotypic Homogeneity in Distinctive Transforming Growth Factor-Beta Induced (TGFBI) Protein Phenotypes. Int J Mol Sci 2021; 22:ijms22031230. [PMID: 33513810 PMCID: PMC7866065 DOI: 10.3390/ijms22031230] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 01/20/2021] [Accepted: 01/20/2021] [Indexed: 11/16/2022] Open
Abstract
Background: To evaluate the distribution of the transforming growth factor-beta induced (TGFBI) corneal dystrophies in a multi-ethnic population in Singapore, and to present the different phenotypes with the same genotype. Methods: This study included 32 patients. Slit lamp biomicroscopy was performed for each patient to determine the disease phenotype. Genomic DNA was extracted from the blood samples and the 17 exons of the TGFBI gene were amplified by PCR and sequenced bi-directionally for genotype analysis. Results: Regarding phenotypes, the study patients comprised 11 (34.4%; 8 with R555W and 3 with R124H mutation) patients with granular corneal dystrophy type 1 (GCD1), 6 (18.8%; 5 with R124H and 1 with R124C mutation) patients with GCD2, 13 (40.6%; 7 with R124C, 2 with H626R, 2 with L550P, 1 with A620D and 1 with H572R) patients with lattice corneal dystrophy (LCD) and 2 (6.3%; 1 with R124L and 1 with R124C) patients with Reis–Bückler corneal dystrophy. Regarding genotype, R124H mutation was associated with GCD2 (5 cases; 62.5%) and GCD1 (3 cases; 37.5%). R124C mutation was associated with LCD (7 cases; 87.5%) and GCD2 (1 case; 12.5%). All the 8 cases (100%) of R555W mutation were associated with GCD1. Conclusions: Although the association between genotype and phenotype was good in most cases (65.7%; 21 of 32 patients), genotype/phenotype discrepancy was observed in a significant number.
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Affiliation(s)
- Sang Beom Han
- Department of Ophthalmology, Kangwon National University School of Medicine, Chuncheon 24289, Korea;
- Department of Ophthalmology, Kangwon National University Hospital, Chuncheon 24289, Korea
| | | | - Chee Wai Wong
- Singapore Eye Research Institute, Singapore 169856, Singapore; (V.A.); (C.W.W.); (S.R.N.)
- Singapore National Eye Centre, Singapore 168751, Singapore
| | - Si Rui Ng
- Singapore Eye Research Institute, Singapore 169856, Singapore; (V.A.); (C.W.W.); (S.R.N.)
- Singapore National Eye Centre, Singapore 168751, Singapore
| | - Jodhbir S. Mehta
- Singapore National Eye Centre, Singapore 168751, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Graduate Medical School, Singapore 169857, Singapore
- Correspondence: ; Tel.: +65-91825146; Fax: +65-08701316622
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Zhang T, Liu C, He J, Kang Y, Wang F, Li S. Cornea guttata associated with special phenotypic variants of granular corneal dystrophy type 2 in a Chinese family. Eur J Ophthalmol 2019; 30:469-474. [PMID: 30871369 DOI: 10.1177/1120672119832176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE The aim of this study was to analyze the relevant gene mutations in a Chinese family with special phenotypic variants of granular corneal dystrophy type 2 with cornea guttata. METHODS A total of 11 individuals from the affected family underwent complete ophthalmic examination. Genomic DNA was extracted from peripheral leukocytes of affected and unaffected family members. High-throughput sequencing was performed to screen for mutations in 290 genes associated with inherited ophthalmic diseases. Results were validated by bidirectional Sanger sequencing. RESULTS An Arg124His (R124H) mutation of the transforming growth factor beta-induced gene was identified in three members of the affected family: the proband (II-1), his mother (I-2), and his son (III-1). The eyes of the proband and his mother had bilateral superficial whitish ring patches with clear centers occupying their central corneas and appeared to be discoid or ring shaped. In addition, specular microscopic examination showed the presence of dark, round bodies. In vivo confocal microscopy showed some hyporeflective round images (cornea guttata), containing occasionally central highlight, in the proband, his mother, and one of his elder sisters. CONCLUSION We report, for the first time, atypical granular corneal dystrophy type 2 with cornea guttata associated with a single R124H mutation in a Chinese family. Our findings emphasize that genotyping is essential for the accurate diagnosis and classification of granular corneal dystrophy type 2.
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Affiliation(s)
- Tao Zhang
- Aier School of Ophthalmology, Central South University and Beijing Aier-Intech Eye Hospital, Beijing, P.R. China
| | - Chang Liu
- Aier School of Ophthalmology, Central South University and Beijing Aier-Intech Eye Hospital, Beijing, P.R. China
| | - Jingliang He
- Aier School of Ophthalmology, Central South University and Beijing Aier-Intech Eye Hospital, Beijing, P.R. China
| | - Yanwei Kang
- Aier School of Ophthalmology, Central South University and Beijing Aier-Intech Eye Hospital, Beijing, P.R. China
| | - Feng Wang
- Aier School of Ophthalmology, Central South University and Beijing Aier-Intech Eye Hospital, Beijing, P.R. China
| | - Shaowei Li
- Aier School of Ophthalmology, Central South University and Beijing Aier-Intech Eye Hospital, Beijing, P.R. China
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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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Abstract
PURPOSE Both granular and lattice deposits are present in Avellino corneal dystrophy (ACD), primarily associated with the R124H mutation of transforming growth factor-β-induced (TGFBIp). We investigated the presence of these deposits in other TGFBI mutations and the use of Thioflavin-T (ThT), a fluorescent amyloid stain for characterizing corneal amyloid deposits. METHODS Surgical corneal specimens of 3 unrelated patients clinically diagnosed with ACD were studied. Corneal sections from normal individuals and patients with prior lattice corneal dystrophy (LCD) were used as controls. Histochemical studies were performed with Congo red and Masson trichrome stains, and fluorescent imaging with scanning laser confocal microscopy was performed for ThT and anti-TGFBIp antibody staining. RESULTS Clinical and histopathological findings supported the diagnoses of ACD in these 3 cases in whom granular deposits stained with Masson trichrome and lattice deposits stained with ThT and Congo red showed birefringence and dichroism as expected. However, genotyping revealed a heterozygous R124C mutation in each case. In addition to classical stromal deposits, unique subepithelial TGFBIp aggregates, which stain with neither ThT nor trichrome, were observed. In control LCD sections, stromal deposits were stained with ThT but not with trichrome, confirming lack of granular deposits. CONCLUSIONS Our results demonstrate that both granular and lattice corneal deposits can be associated with R124C mutation in addition to the more common R124H mutation. An additional feature of nonhyaline, nonamyloid, TGFBIp subepithelial deposits might substantiate the categorization of such cases as a variant form of ACD. This study further validates ThT staining for detection of amyloid TGFBIp deposits.
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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: 195] [Impact Index Per Article: 12.2] [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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Aldave AJ, Yellore VS, Sonmez B, Bourla N, Salem AK, Khan MA, Rayner SA, Glasgow BJ. A novel variant of combined granular-lattice corneal dystrophy associated with the Met619Lys mutation in the TGFBI gene. ACTA ACUST UNITED AC 2008; 126:371-7. [PMID: 18332318 DOI: 10.1001/archopht.126.3.371] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
OBJECTIVE To report a novel mutation in TGFBI (GenBank NM_000358), p.Met619Lys, associated with a variant of combined granular-lattice corneal dystrophy. METHODS Slitlamp examination and DNA collection from the proband and affected and unaffected relatives. All 17 exons of TGFBI were amplified and sequenced in the proband. Exon 14 was amplified and sequenced in the proband's family members and in 100 controls. Histopathologic examination of the excised corneal buttons from the proband and 3 family members was also performed. RESULTS Affected individuals demonstrated an age-dependent phenotype, with the progression from central subepithelial needlelike deposits in younger individuals to polymorphic anterior stromal opacities in older family members. Screening of TGFBI in the proband demonstrated a novel mutation, p.Met619Lys, which was also present in all affected family members. Histopathologic examination revealed stromal deposits that stained with the Congo red and Masson trichrome stains as well as an antibody to the protein product of TGFBI. CONCLUSIONS We present a unique corneal dystrophy phenotype associated with the novel p.Met619Lys mutation in TGFBI. Clinical Relevance The atypical and variable phenotype and the demonstration of both hyaline and amyloid stromal deposits indicate that neither clinical nor histopathologic features may be relied on to accurately diagnose and classify the corneal dystrophies.
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Affiliation(s)
- Anthony J Aldave
- Jules Stein Eye Institute, University of California, Los Angeles, CA 90095, USA.
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Zhao XC, Nakamura H, Subramanyam S, Stock LE, Gillette TE, Yoshikawa S, Ma X, Yee RW. Spontaneous and inheritable R555Q mutation in the TGFBI/BIGH3 gene in two unrelated families exhibiting Bowman's layer corneal dystrophy. Ophthalmology 2007; 114:e39-46. [PMID: 17980739 DOI: 10.1016/j.ophtha.2007.07.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2007] [Revised: 07/20/2007] [Accepted: 07/25/2007] [Indexed: 11/18/2022] Open
Abstract
PURPOSE Bowman's layer corneal dystrophies (CDBs) include 2 distinct types: CDB1, or Reis-Bücklers (RBCD), and CDB2, or Thiel-Behnke (TBCD). We studied the genetic basis of 2 cases of apparent spontaneous CDB mutations and attempted to determine if these are sporadic and inheritable mutations. DESIGN Retrospective molecular genetic study and case report. PARTICIPANTS Twelve patients were recruited from 2 unrelated families for this study, including 2 affected individuals from one family (family A) and 1 affected individual from another (family B). METHODS Slit-lamp examination was performed for each patient to determine the disease phenotype. Histological analysis of affected cornea specimens was used for identification of pathogenic corneal opacities in 2 affected patients from family A. MAIN OUTCOME MEASURES Genomic DNA was isolated from the blood samples and used for mutation screening of the TGFBI/BIGH3 gene. Sixteen polymorphic DNA markers from 9 different chromosomes were used to establish the maternity and paternity of the 2 probands. RESULTS The 2 families were confirmed to be unrelated. The age onset of ocular symptoms was <2 years for all 3 affected patients. Clinical diagnoses of CDB1 (RBCD) and CDB2 (TBCD) were made for probands A and B, respectively. The affected corneas showed epithelial haze with diffuse, irregular, patchy opacities in a honeycomb and geographic pattern. Subepithelial plaques, increased trichome staining of anterior stroma, and irregular Bowman's layer were observed. An R555Q mutation was found in TGFBI/BIGH3 in the 2 probands but not in their parents. The son of proband A was also affected and apparently inherited his disease allele from his father. CONCLUSION The R555Q mutation occurred spontaneously and independently in the 2 unrelated CDB families and was confirmed to be transmitted to the next generation in 1 of the 2 families. These findings strongly support the notion that a genetic diagnosis should be determined for CDB and other dystrophies associated with mutations in TGFBI/BIGH3. The discovery of a spontaneous mutation should alert clinicians to be aware of the existence of genetic alterations for their patients without apparent family history of the disease.
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Affiliation(s)
- Xinping C Zhao
- Department of Ophthalmology and Visual Science and Hermann Eye Center, University of Texas Health Science Center at Houston, Houston, Texas, USA.
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Santos LN, Fernandes BF, de Moura LR, Cheema DP, Maloney S, Logan P, Burnier MN. Histopathologic Study of Corneal Stromal Dystrophies. Cornea 2007; 26:1027-31. [PMID: 17893527 DOI: 10.1097/ico.0b013e318123f298] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To determine the frequency and describe the histopathologic features of stromal corneal dystrophies over a 10-year period. METHODS A single-centered, retrospective analysis was performed on corneal specimens diagnosed as stromal dystrophies retrieved from the Henry C. Witelson Ophthalmic Pathology Laboratory and Registry (Montreal, Canada) over a period of 10 years. Corneal specimens obtained during keratoplasty were subjected to hematoxylin and eosin, periodic acid-Schiff, and other special staining. RESULTS During the period of the study, 885 corneal specimens from penetrating keratoplasties were received. Twenty-six (2.9%) specimens from a total of 22 patients showed stromal corneal dystrophies: 17 (65.4%) eyes with lattice dystrophy, 5 (19.2%) eyes with combined granular/lattice ("Avellino") dystrophy, 3 (11.5%) eyes with granular dystrophy, and 1 (3.9%) eye with macular dystrophy. CONCLUSIONS Corneal stromal dystrophies have distinct histopathologic features, which can be diagnosed with routine and special staining, particularly for combined granular/lattice (Avellino) dystrophy. Clinically, combined granular/lattice (Avellino) dystrophy can have features of both lattice and granular dystrophies, which can be misleading for diagnosis. Lattice dystrophy was the most frequent stromal dystrophy in this particular population.
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Affiliation(s)
- Leonardo N Santos
- Department of Ophthalmology and Pathology, The McGill University Health Center & Henry C. Witelson Ocular Pathology Laboratory, Montreal, Canada.
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