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Shu DY, Chaudhary S, Cho KS, Lennikov A, Miller WP, Thorn DC, Yang M, McKay TB. Role of Oxidative Stress in Ocular Diseases: A Balancing Act. Metabolites 2023; 13:187. [PMID: 36837806 PMCID: PMC9960073 DOI: 10.3390/metabo13020187] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Redox homeostasis is a delicate balancing act of maintaining appropriate levels of antioxidant defense mechanisms and reactive oxidizing oxygen and nitrogen species. Any disruption of this balance leads to oxidative stress, which is a key pathogenic factor in several ocular diseases. In this review, we present the current evidence for oxidative stress and mitochondrial dysfunction in conditions affecting both the anterior segment (e.g., dry eye disease, keratoconus, cataract) and posterior segment (age-related macular degeneration, proliferative vitreoretinopathy, diabetic retinopathy, glaucoma) of the human eye. We posit that further development of therapeutic interventions to promote pro-regenerative responses and maintenance of the redox balance may delay or prevent the progression of these major ocular pathologies. Continued efforts in this field will not only yield a better understanding of the molecular mechanisms underlying the pathogenesis of ocular diseases but also enable the identification of novel druggable redox targets and antioxidant therapies.
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Affiliation(s)
- Daisy Y. Shu
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Suman Chaudhary
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Kin-Sang Cho
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Anton Lennikov
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - William P. Miller
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - David C. Thorn
- Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA
| | - Menglu Yang
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, Boston, MA 02114, USA
| | - Tina B. McKay
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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2
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The Role of Estriol and Estrone in Keratoconic Stromal Sex Hormone Receptors. Int J Mol Sci 2022; 23:ijms23020916. [PMID: 35055103 PMCID: PMC8779160 DOI: 10.3390/ijms23020916] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/06/2022] [Accepted: 01/08/2022] [Indexed: 02/04/2023] Open
Abstract
Keratoconus (KC) is a progressive corneal thinning disease that manifests in puberty and worsens during pregnancy. KC onset and progression are attributed to diverse factors that include: environmental, genetics, and hormonal imbalances; however, the pathobiology remains elusive. This study aims to determine the role of corneal stroma sex hormone receptors in KC and their interplay with estrone (E1) and estriol (E3) using our established 3D in vitro model. Healthy cornea stromal cells (HCFs) and KC cornea stromal cells (HKCs), both male and female, were stimulated with various concentrations of E1 and E3. Significant changes were observed between cell types, as well as between males and females in the sex hormone receptors tested; androgen receptor (AR), progesterone receptor (PR), estrogen receptor alpha (ERα), and estrogen receptor beta (ERβ) using Western blot analysis. E1 and E3 stimulations in HCF females showed AR, PR, and ERβ were significantly upregulated compared to HCF males. In contrast, ERα and ERβ had significantly higher expression in HKC's females than HKC's males. Our data suggest that the human cornea is a sex-dependent, hormone-responsive tissue that is significantly influenced by E1 and E3. Therefore, it is plausible that E1, E3, and sex hormone receptors are involved in the KC pathobiology, warranting further investigation.
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Lopes AG, de Almeida GC, Miola MP, Teixeira RM, Pires FCBL, Miani RA, de Mattos LC, Brandão CC, Castiglioni L. Absence of significant genetic alterations in the VSX1, SOD1, TIMP3, and LOX genes in Brazilian patients with Keratoconus. Ophthalmic Genet 2021; 43:73-79. [PMID: 34802378 DOI: 10.1080/13816810.2021.1992785] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
PURPOSE To identify inherited or acquired mutations in the VSX1, SOD1, TIMP3 and LOX genes from the combined analysis of corneal and blood samples from patients with Keratoconus. METHODS The casuistry was consisted of samples of peripheral blood and corneal epithelium from 35 unrelated patients with Keratoconus who were submitted to corneal crosslink treatment. Also, blood and corneal epithelium samples from 89 non-keratoconic patients were used to compose the control group. Ophthalmologic evaluations included a clinical examination, topography and tomography. DNA samples were extracted from peripheral blood and from corneal epithelium in both groups and all coding regions of the VSX1, SOD1, TIMP3 and LOX genes were amplified by polymerase chain reaction, denatured and subjected to polyacrylamide gel electrophoresis. Mutational screening was performed by single-strand conformation polymorphism and direct DNA sequencing. RESULTS No pathogenic variant was found in all coding regions of VSX1, SOD1, TIMP3 and LOX genes, we detected only few SNPs (single-nucleotide polymorphisms). Among the polymorphisms stand out three of them, corresponding to the synonymous exchange of amino acids: exon 3 of VSX1 Ala182Ala and exon 3 of TIMP3 His83His and Ser87Ser; in patients with Keratoconus and also in control subjects. All the polymorphisms were found in samples of corneal epithelium and corresponding blood. CONCLUSION There is absence of KC pathogenic related to mutations in the VSX1, SOD1, TIMP3 and LOX genes in the studied patients.
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Affiliation(s)
- Alessandro Garcia Lopes
- Biology Department, Instituto De Biociências, Letras E, Universidade Estadual Paulista "Júlio De Mesquita Filho", São José do Rio Preto, São Paulo, Brazil.,Immunogenetics Laboratory, Molecular Biology Department, Faculdade De Medicina De São José Do Rio Preto (FAMERP), São José do Rio Preto, São Paulo, Brazil
| | - Gildásio Castello de Almeida
- Ophthalmology Outpatient Clinic, Hospital De Base Da Fundação Faculdade Regional De Medicina (HB-, São José do Rio Preto, São Paulo, Brazil
| | - Marcos Paulo Miola
- Immunogenetics Laboratory, Molecular Biology Department, Faculdade De Medicina De São José Do Rio Preto (FAMERP), São José do Rio Preto, São Paulo, Brazil
| | - Ronan Marques Teixeira
- Biology Department, Instituto De Biociências, Letras E, Universidade Estadual Paulista "Júlio De Mesquita Filho", São José do Rio Preto, São Paulo, Brazil
| | | | | | - Luiz Carlos de Mattos
- Immunogenetics Laboratory, Molecular Biology Department, Faculdade De Medicina De São José Do Rio Preto (FAMERP), São José do Rio Preto, São Paulo, Brazil
| | - Cinara Cássia Brandão
- Immunogenetics Laboratory, Molecular Biology Department, Faculdade De Medicina De São José Do Rio Preto (FAMERP), São José do Rio Preto, São Paulo, Brazil
| | - Lilian Castiglioni
- Biology Department, Instituto De Biociências, Letras E, Universidade Estadual Paulista "Júlio De Mesquita Filho", São José do Rio Preto, São Paulo, Brazil.,Epidemiology and Collective Health, Faculdade De Medicina De São José Do Rio Preto (FAMERP), São José do Rio Preto, São Paulo, Brazil
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4
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Ates KM, Estes AJ, Liu Y. Potential underlying genetic associations between keratoconus and diabetes mellitus. ADVANCES IN OPHTHALMOLOGY PRACTICE AND RESEARCH 2021; 1:100005. [PMID: 34746916 PMCID: PMC8570550 DOI: 10.1016/j.aopr.2021.100005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/18/2021] [Accepted: 08/29/2021] [Indexed: 12/14/2022]
Abstract
Background Keratoconus (KC) is the most common ectatic corneal disease, characterized by significantly localized thinning of the corneal stroma. Genetic, environmental, hormonal, and metabolic factors contribute to the pathogenesis of KC. Additionally, multiple comorbidities, such as diabetes mellitus, may affect the risk of KC. Main Body Patients with diabetes mellitus (DM) have been reported to have lower risk of developing KC by way of increased endogenous collagen crosslinking in response to chronic hyperglycemia. However, this remains a debated topic as other studies have suggested either a positive association or no association between DM and KC. To gain further insight into the underlying genetic components of these two diseases, we reviewed candidate genes associated with KC and central corneal thickness in the literature. We then explored how these genes may be regulated similarly or differentially under hyperglycemic conditions and the role they play in the systemic complications associated with DM. Conclusion Our comprehensive review of potential genetic factors underlying KC and DM provides a direction for future studies to further determine the genetic etiology of KC and how it is influenced by systemic diseases such as diabetes.
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Affiliation(s)
- Kristin M. Ates
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Amy J. Estes
- Department of Ophthalmology, Medical College of Georgia, Augusta University, Augusta, GA, USA
- James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - Yutao Liu
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
- James and Jean Culver Vision Discovery Institute, Medical College of Georgia, Augusta University, Augusta, GA, USA
- Center for Biotechnology and Genomic Medicine, Medical College of Georgia, Augusta University, Augusta, GA, USA
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5
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Burdon KP, Vincent AL. Insights into keratoconus from a genetic perspective. Clin Exp Optom 2021; 96:146-54. [DOI: 10.1111/cxo.12024] [Citation(s) in RCA: 80] [Impact Index Per Article: 26.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Revised: 10/18/2012] [Accepted: 10/30/2012] [Indexed: 01/08/2023] Open
Affiliation(s)
- Kathryn P Burdon
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia,
| | - Andrea L Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand,
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Shinde V, Sobreira N, Wohler ES, Maiti G, Hu N, Silvestri G, George S, Jackson J, Chakravarti A, Willoughby CE, Chakravarti S. Pathogenic alleles in microtubule, secretory granule and extracellular matrix-related genes in familial keratoconus. Hum Mol Genet 2021; 30:658-671. [PMID: 33729517 DOI: 10.1093/hmg/ddab075] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 03/03/2021] [Accepted: 03/05/2021] [Indexed: 12/30/2022] Open
Abstract
Keratoconus is a common corneal defect with a complex genetic basis. By whole exome sequencing of affected members from 11 multiplex families of European ancestry, we identified 23 rare, heterozygous, potentially pathogenic variants in 8 genes. These include nonsynonymous single amino acid substitutions in HSPG2, EML6 and CENPF in two families each, and in NBEAL2, LRP1B, PIK3CG and MRGPRD in three families each; ITGAX had nonsynonymous single amino acid substitutions in two families and an indel with a base substitution producing a nonsense allele in the third family. Only HSPG2, EML6 and CENPF have been associated with ocular phenotypes previously. With the exception of MRGPRD and ITGAX, we detected the transcript and encoded protein of the remaining genes in the cornea and corneal cell cultures. Cultured stromal cells showed cytoplasmic punctate staining of NBEAL2, staining of the fibrillar cytoskeletal network by EML6, while CENPF localized to the basal body of primary cilia. We inhibited the expression of HSPG2, EML6, NBEAL2 and CENPF in stromal cell cultures and assayed for the expression of COL1A1 as a readout of corneal matrix production. An upregulation in COL1A1 after siRNA inhibition indicated their functional link to stromal cell biology. For ITGAX, encoding a leukocyte integrin, we assayed its level in the sera of 3 affected families compared with 10 unrelated controls to detect an increase in all affecteds. Our study identified genes that regulate the cytoskeleton, protein trafficking and secretion, barrier tissue function and response to injury and inflammation, as being relevant to keratoconus.
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Affiliation(s)
- Vishal Shinde
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Nara Sobreira
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Elizabeth S Wohler
- McKusick-Nathans Department of Genetic Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | - George Maiti
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Nan Hu
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Giuliana Silvestri
- Department of Ophthalmology, Belfast Health and Social Care Trust, Belfast BT12 6BA UK
| | - Sonia George
- Department of Ophthalmology, Belfast Health and Social Care Trust, Belfast BT12 6BA UK
| | - Jonathan Jackson
- Department of Ophthalmology, Belfast Health and Social Care Trust, Belfast BT12 6BA UK
| | - Aravinda Chakravarti
- Center for Human Genetics and Genomics, NYU Grossman School of Medicine, New York, NY 10016, USA
| | - Colin E Willoughby
- Department of Ophthalmology, Belfast Health and Social Care Trust, Belfast BT12 6BA UK.,Genomic Medicine, Biomedical Sciences Research Institute, Ulster University, Coleraine BT52 1SA, UK
| | - Shukti Chakravarti
- Department of Ophthalmology, NYU Grossman School of Medicine, New York, NY 10016, USA.,Department of Pathology, NYU Grossman School of Medicine, New York, NY 10016, USA
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Veerappa AM. Cascade of interactions between candidate genes reveals convergent mechanisms in keratoconus disease pathogenesis. Ophthalmic Genet 2021; 42:114-131. [PMID: 33554698 DOI: 10.1080/13816810.2020.1868013] [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: 10/22/2022]
Abstract
Keratoconus is a progressive thinning, steepening and distortion of the cornea which can lead to loss of vision if left untreated. Keratoconus has a complex multifactorial etiology, with genetic and environmental components contributing to the disease pathophysiology. Studies have observed high concordance between monozygotic twins, discordance between dizygotic twins, and high familial segregation indicating the presence of a very strong genetic component in the pathogenesis of keratoconus. The use of genome-wide linkage studies on families and twins, genome-wide association studies (GWAS) on case-controls, next-generation sequencing (NGS)-based genomic screens on both familial and non-familial cohorts have led to the identification of keratoconus candidate genes with much greater success and increased resproducibility of genetic findings. This review focuses on candidate genes identified till date and attempts to understand their role in biological processes underlying keratoconus pathogenesis. In addition, using these genes I propose molecular pathways that could contribute to keratoconus pathogenesis. The pathways identified the presence of direct cross-talk between known candidate genes of keratoconus and remarkably, 28 known candidate genes have a direct relationship among themselves that involves direct protein-protein binding, regulatory activities such as activation and inhibition, chaperone, transcriptional activation/co-activation, and enzyme catalysis. This review attempts to describe these relationships and cross-talks in the context of keratoconus pathogenesis.
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Affiliation(s)
- Avinash M Veerappa
- Department of Ophthalmology, NYU Langone Medical Center, New York, New York, USA
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8
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Ferrari G, Rama P. The keratoconus enigma: A review with emphasis on pathogenesis. Ocul Surf 2020; 18:363-373. [PMID: 32234342 DOI: 10.1016/j.jtos.2020.03.006] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/11/2020] [Accepted: 03/19/2020] [Indexed: 12/16/2022]
Abstract
PURPOSE To review the literature on the etiopathogenesis of keratoconus (KC). METHODS A literature search was conducted using PUBMED and Google Scholar for keratoconus. The authors analyzed epidemiology studies, reviews, and case reports. RESULTS Atopy and ocular surface inflammation are a common features of KC and should lead to a reconsideration of the traditional definition of KC as a "non inflammatory" condition. Co-morbidities suggest that KC may be the ocular manifestation of a systemic disease. Finally, KC shows higher prevalence in certain ethnicities, which calls into question the status of KC as a rare disease, at least in these communities. CONCLUSION We believe that future studies should test whether selected, high prevalence populations exhibit specific genetic background and/or ethno-specific environmental risk factors.
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Affiliation(s)
- Giulio Ferrari
- San Raffaele Hospital, Cornea and Ocular Surface Unit, Eye Repair Lab, Italy.
| | - Paolo Rama
- San Raffaele Hospital, Cornea and Ocular Surface Unit, Eye Repair Lab, Italy
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9
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Cao K, Sahebjada S, Richardson AJ, Baird PN. Do age-related macular degeneration genes show association with keratoconus? EYE AND VISION 2019; 6:38. [PMID: 31819893 PMCID: PMC6885317 DOI: 10.1186/s40662-019-0164-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 11/03/2019] [Indexed: 01/06/2023]
Abstract
Background Keratoconus (KC) is a common corneal condition with an unknown gender predominance. Although numerous studies have investigated the genetic component of KC, no specific genes have yet been attributed to the condition. We recently reported posterior segment changes occurring in the eyes of KC patients. However, it is not clear whether these changes are part of KC pathogenesis or reflect changes in anatomical features of the eye manifested by changes at the cornea. Given retinal changes represent the main characteristics observed in age-related macular degeneration (AMD) and that pleiotropy has been demonstrated between different eye diseases, we wished to assess if known AMD associated genes were also associated with KC. Methods A total of 248 KC subjects and 366 non-KC (control) subjects were recruited from public and private clinics in Melbourne for this analysis. Nineteen single nucleotide polymorphisms (SNPs) previously associated with AMD, including rs10490924 (ARMS2/HTRA1), rs10737680 (CFH), rs13278062 (TNFRSF10A), rs1864163 (CETP), rs2230199 (C3), rs3130783 (IER3/DDR1), rs334353 (TGFBR1), rs3812111 (COL10A1), rs429608 (C2/CFB), rs4420638 (APOE), rs4698775 (CFI), rs5749482 (TIMP3), rs6795735 (ADAMTS9), rs8017304 (RAD51B), rs8135665 (SLC16A8), rs920915 (LIPC), rs943080 (VEGFA), rs9542236 (B3GALTL) and rs13081855 (COL8A1/FILIP1L), were genotyped in this cohort. Logistic regression was applied to evaluate the association between these SNPs and KC on both genders together, as well as each gender separately. Linear regression was also applied to assess the association between SNPs and corneal curvature. Bonferroni correction was applied to adjust for multiple testing. Results Genotyping data were available for 18 SNPs. The SNP, rs6795735 (ADAMTS9) was significantly associated with KC (p = 3.5 × 10- 4) when both genders were assessed, whereas rs5749482 (TIMP3) was only associated in males (p = 7.7 × 10- 4) following Bonferroni multiple correction. However, when the covariates of age and gender were included, the associations became non-significant. In addition, none of the SNPs appeared significant for corneal curvature. Conclusions Our study suggested a potential association of rs6795735 in the ADAMTS9 gene and rs5749482 in the TIMP3 gene in KC and that different associations may be gender specific. Overall, SNPs initially identified as associated with AMD following multiple correction may be further impacted by other factors such as age or gender and further studies are needed to resolve this issue.
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Affiliation(s)
- Ke Cao
- 1Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,2Department of Surgery, Ophthalmology, The University of Melbourne, 32 Gisborne Street, East Melbourne, VIC 3000 Australia
| | - Srujana Sahebjada
- 1Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia.,2Department of Surgery, Ophthalmology, The University of Melbourne, 32 Gisborne Street, East Melbourne, VIC 3000 Australia
| | - Andrea J Richardson
- 1Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Paul N Baird
- 2Department of Surgery, Ophthalmology, The University of Melbourne, 32 Gisborne Street, East Melbourne, VIC 3000 Australia
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10
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Nabil KM, Elhady GM, Morsy H. The Association Between Interleukin 1 Beta Promoter Polymorphisms And Keratoconus Incidence And Severity In An Egyptian Population. Clin Ophthalmol 2019; 13:2217-2223. [PMID: 31814706 PMCID: PMC6863178 DOI: 10.2147/opth.s220723] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/27/2019] [Indexed: 11/23/2022] Open
Abstract
Purpose In the present study, we investigated whether interleukin 1 beta (IL1B) promoter polymorphisms are associated with keratoconus in an Egyptian population and their association with disease severity. Methods A total of 95 Egyptian keratoconus patients and 126 Egyptian healthy controls were enrolled in the study. Two IL1B single nucleotide polymorphisms (SNPs) (rs1143627 and rs16944) were genotyped using Taqman real-time PCR to compare haplotype, genotype, and allele frequencies between cases and controls (primary outcome) and their association with disease severity (secondary outcome). Results Statistically significant association was observed for rs1143627 and rs16944; the T allele of rs1143627 and the G allele of rs16944 were associated with an increased risk of keratoconus (p < 0.001, odds ratio = 3.313, 4.770, respectively). The TT genotype of rs1143627 and the GG genotype of rs16944 were strongly associated with an increased risk of keratoconus (p < 0.001, odds ratio = 5.631, 11.478, respectively). The G allele of rs16944 was associated with an increased curvature of the flattest corneal meridian Kf in keratoconus (p = 0.041). The GG genotype of rs16944 was associated with an increased curvature of the flattest corneal meridian Kf, steepest corneal meridian Ks and average corneal curvature Kavg in keratoconus (p = 0.01, 0.046, 0.023, respectively). Conclusion IL1B is suspected to play a crucial role, both in development and severity of keratoconus in Egyptian population.
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Affiliation(s)
- Karim Mahmoud Nabil
- Department of Ophthalmology, Faculty of Medicine, University of Alexandria, Alexandria, Egypt
| | - Ghada Mohamed Elhady
- Department of Human Genetics, Medical Research Institute, University of Alexandria, Alexandria, Egypt
| | - Heba Morsy
- Department of Human Genetics, Medical Research Institute, University of Alexandria, Alexandria, Egypt
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Skorodumova LO, Belodedova AV, Sharova EI, Malyugin BE. [Search for genetic markers for precise diagnostics of keratoconus]. BIOMEDIT︠S︡INSKAI︠A︡ KHIMII︠A︡ 2019; 65:9-20. [PMID: 30816092 DOI: 10.18097/pbmc20196501009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Keratoconus is a chronic disorder of the cornea, characterized by its progressive thinning, stretching, and conical protrusion. Diagnostics of subclinical keratoconus, as well as its early stages (forme fruste), is a complex problem. The presence of these forms of keratoconus in a patient is one of the reasons for the development of keratectasia after laser refractive surgery. Currently, the role of genetic factors in keratoconus development has been proven. This indicates the possibility of diagnostics of subclinical and forme fruste keratoconus using genetic markers. Knowledge about the patient's genetic susceptibility to keratoconus would allow correcting the tactics of treatment of refractive anomalies and avoiding serious side effects. The studies of causal mutations indicate the genetic heterogeneity of keratoconus, which complicates the development of a diagnostic panel. Selection of candidate variants from the currently known ones based on clear criteria may be one of the approaches for diagnostic markers search. In this review, we have analyzed articles on keratoconus markers in order to form a list of candidate variants for genotyping in the Russian population. The selection criteria took into account the complexes of symptoms in which a marker was found, populations in which a particular marker was investigated, the presence and results of replication studies. The analysis included markers in VSX1, SOD1, ZEB1, LOX, CAST, DOCK9, TGFBI, HGF, MAP3K19, KCND3, COL4A3, COL4A4, COL5A1, FNDC3B, FOXO1, BANP-ZNF469, MPDZ-NF1B, WNT10A genes. Based on the results of the analysis, the following candidate variants were selected for genotyping in the Russian population of patients with keratoconus: rs1536482 and rs7044529 in the COL5A1 gene, rs5745752 and rs2286194 in the HGF gene, rs4954218 in the MAP3K19 gene, rs4839200 near the KCND3 gene, rs2721051 near the FOXO1 gene, rs1324183 between the MPDZ and the NF1B genes, and rs121908120 in the WNT10A gene.
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Affiliation(s)
- L O Skorodumova
- Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia
| | - A V Belodedova
- Fyodorov Eye Microsurgery Complex Federal State Institution, Moscow, Russia
| | - E I Sharova
- Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia
| | - B E Malyugin
- Fyodorov Eye Microsurgery Complex Federal State Institution, Moscow, Russia
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Atilano SR, Lee DH, Fukuhara PS, Chwa M, Nesburn AB, Udar N, Kenney MC. Corneal Oxidative Damage in Keratoconus Cells due to Decreased Oxidant Elimination from Modified Expression Levels of SOD Enzymes, PRDX6, SCARA3, CPSF3, and FOXM1. J Ophthalmic Vis Res 2019; 14:62-70. [PMID: 30820289 PMCID: PMC6388514 DOI: 10.4103/jovr.jovr_80_18] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Purpose: To compare the levels of gene expression for enzymes involved in production and elimination of reactive oxygen/nitrogen species (ROS/RNS) in normal human corneal cells (NL cells) with those in human corneal cells with keratoconus (KC cells) in vitro. Methods: Primary NL and KC stromal fibroblast cultures were incubated with apocynin (an inhibitor of NADPH oxidase) or N-nitro-L-arginine (N-LLA; an inhibitor of nitric oxide synthase). ROS/RNS levels were measured using an H2 DCFDA fluorescent assay. The RT2 Profiler™ PCR Array for Oxidative Stress and Antioxidant Defense was used for initial screening of the NL and KC cultures. Transcription levels for genes related to production or elimination of ROS/RNS were analyzed using quantitative PCR. Immunohistochemistry was performed on 10 intact human corneas using antibodies against SCARA3 and CPSF3. Results: Array screening of 84 antioxidant-related genes identified 12 genes that were differentially expressed between NL and KC cultures. Compared with NL cells, quantitative PCR showed that KC cells had decreased expression of antioxidant genes SCARA3 isoform 2 (0.59-fold, P = 0.02) and FOXM1 isoform 1 (0.61-fold, P = 0.03). KC cells also had downregulation of the antioxidant genes SOD1 (0.4-fold, P = 0.0001) and SOD3 (0.37-fold, P = 0.02) but increased expression of SOD2 (3.3-fold, P < 0.0001), PRDX6 (1.47-fold, P = 0.01), and CPSF3 (1.44-fold, P = 0.02). Conclusion: The difference in expression of antioxidant enzymes between KC and NL suggests that the oxidative stress imbalances found in KC are caused by defects in ROS/RNS removal rather than increased ROS/RNS production.
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Affiliation(s)
- Shari R Atilano
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
| | - Daniel H Lee
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
| | - Paula S Fukuhara
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
| | - Marilyn Chwa
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
| | - Anthony B Nesburn
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA.,Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Nitin Udar
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
| | - M Cristina Kenney
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA.,Department of Pathology and Laboratory Medicine, University of California Irvine, Irvine, CA, USA
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13
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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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Panahi Y, Azimi A, Naderi M, Jadidi K, Sahebkar A. An analytical enrichment-based review of structural genetic studies on keratoconus. J Cell Biochem 2018; 120:4748-4756. [PMID: 30260013 DOI: 10.1002/jcb.27764] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2018] [Accepted: 09/06/2018] [Indexed: 12/19/2022]
Abstract
Keratoconus is a progressive bilateral corneal protrusion that leads to irregular astigmatism and impairment of vision. Keratoconus is an etiologically heterogeneous corneal dystrophy and both environmental and genetic factors play a role in its etiopathogenesis. In this analytical review, we have studied all the genes that are structurally associated with keratoconus and have tried to explain the function of each gene and its association with other eye disorders in a concise way. In addition, using gene set enrichment analysis, it was attempted to find the most important impaired metabolic pathways in keratoconus. Several genetic studies have been carried out on keratoconus and several genes have been identified as risk factors involved in the etiology of the disease. In the current study, 16 studies, including nine association studies, five genome-wide association studies, one linkage study, and one meta-analysis, were reviewed and based on the 19 genes found, enrichment was performed and the most important metabolic pathways involved in the disease were identified. The enrichment results indicated that the two pathways, interleukin 1 processing and assembly of collagen fibrils, are significantly associated with the disease. Obviously, the results of this study, in addition to providing information about the genes involved in the disease, can provide an integrated insight into the gene-based etiology of keratoconus and therapeutic opportunities thereof.
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Affiliation(s)
- Yunes Panahi
- Chemical Injuries Research Center, System Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Ali Azimi
- Department of Ophthalmology, Poostchi Eye Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mostafa Naderi
- Chemical Injuries Research Center, System Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Khosrow Jadidi
- Chemical Injuries Research Center, System Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Amirhossein Sahebkar
- Biotechnology Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,Neurogenic inflammation Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran.,School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran
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15
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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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16
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Valgaeren H, Koppen C, Van Camp G. A new perspective on the genetics of keratoconus: why have we not been more successful? Ophthalmic Genet 2017; 39:158-174. [DOI: 10.1080/13816810.2017.1393831] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Hanne Valgaeren
- Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp & Antwerp University Hospital, Antwerp, Belgium
| | - Carina Koppen
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
- Department of Ophthalmology, Visual Optics and Visual Rehabilitation, University of Antwerp, Antwerp, Belgium
| | - Guy Van Camp
- Department of Biomedical Sciences, Center of Medical Genetics, University of Antwerp & Antwerp University Hospital, Antwerp, Belgium
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17
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Analysis of the VSX1 gene in sporadic keratoconus patients from China. BMC Ophthalmol 2017; 17:173. [PMID: 28950846 PMCID: PMC5615802 DOI: 10.1186/s12886-017-0567-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Accepted: 09/20/2017] [Indexed: 12/15/2022] Open
Abstract
Background Keratoconus normally presents as a sporadic disease. Although different studies have found sequence variants of the visual system homeobox 1 (VSX1) gene associated with keratoconus in humans, no research has detected such variants in sporadic keratoconus patients from China. To investigate the possibility of VSX1 being a candidate susceptibility gene for Chinese patients with sporadic keratoconus, we performed sequence screening of this gene in such patients. Methods Whole DNA was obtained from the leukocytes in the peripheral venous blood of 50 patients with sporadic keratoconus and 50 control subjects without this ocular disorder. Polymerase chain reaction single-strand conformation polymorphism analysis and direct DNA sequencing technology were used to detect sequence variation in the five exons and splicing regions of the introns of the VSX1 gene. The sequencing results were analyzed using DNAstar software. Results One novel missense heterozygous sequence variant (p.Arg131Pro) was found in the first exon of the VSX1 gene in one keratoconus patient. Another heterozygous sequence variant (p.Gly160Val) in the second exon was found in two keratoconus patients. These variants were not detected in the control subjects. In the third intron of the VSX1 gene, c.8326G > A nucleotide substitution (including heterozygous and homozygous change) was also discovered. The frequency of this variation did not differ significantly between patients and controls, it should belong to single-nucleotide polymorphism of the VSX1 gene. Bioinformatic analysis also predicted that one missense sequence variation (p.Arg131Pro) may not cause a pathogenic change. Conclusions In this study, we added one novel missense sequence variation (p.Arg131Pro) in the coding region of the VSX1 gene to the range of VSX1 coding region variations observed in patients with sporadic keratoconus from China. Our work suggests that VSX1 sequence variants might be involved in the pathogenesis of sporadic keratoconus, but their precise role in disease causation requires further investigation.
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18
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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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19
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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: 269] [Impact Index Per Article: 38.4] [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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20
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Rong SS, Ma STU, Yu XT, Ma L, Chu WK, Chan TCY, Wang YM, Young AL, Pang CP, Jhanji V, Chen LJ. Genetic associations for keratoconus: a systematic review and meta-analysis. Sci Rep 2017; 7:4620. [PMID: 28676647 PMCID: PMC5496893 DOI: 10.1038/s41598-017-04393-2] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 05/15/2017] [Indexed: 12/21/2022] Open
Abstract
Genetic associations for keratoconus could be useful for understanding disease pathogenesis and discovering biomarkers for early detection of the disease. We conducted a systematic review and meta-analysis to summarize all reported genetic associations for the disease. We searched in the MEDLINE, Embase, Web of Science, and HuGENET databases for genetic studies of keratoconus published from 1950 to June 2016. The summary odds ratio and 95% confidence intervals of all polymorphisms were estimated using the random-effect model. Among 639 reports that were retrieved, 24 fulfilled required criteria as eligible studies for meta-analysis, involving a total of 53 polymorphisms in 28 genes/loci. Results of our meta-analysis lead to the prioritization of 8 single-nucleotide polymorphisms (SNPs) in 6 genes/loci for keratoconus in Whites. Of them 5 genes/loci were originally detected in genome-wide association studies, including FOXO1 (rs2721051, P = 5.6 × 10-11), RXRA-COL5A1 (rs1536482, P = 2.5 × 10-9), FNDC3B (rs4894535, P = 1.4 × 10-8), IMMP2L (rs757219, P = 6.1 × 10-7; rs214884, P = 2.3 × 10-5), and BANP-ZNF469 (rs9938149, P = 1.3 × 10-5). The gene COL4A4 (rs2229813, P = 1.3 × 10-12; rs2228557, P = 4.5 × 10-7) was identified in previous candidate gene studies. We also found SNPs in 10 genes/loci that had a summary P value < 0.05. Sensitivity analysis indicated that the results were robust. Replication studies and understanding the roles of these genes in keratoconus are warranted.
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Affiliation(s)
- Shi Song Rong
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Sarah Tsz Ue Ma
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Xin Ting Yu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong, China
- Department of Gastroenterology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | - Li Ma
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Wai Kit Chu
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Tommy Chung Yan Chan
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
- Hong Kong Eye Hospital, Kowloon, Hong Kong, China
| | - Yu Meng Wang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Alvin L Young
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China
| | - Chi Pui Pang
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - Vishal Jhanji
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China.
- UPMC Eye Centre, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
| | - Li Jia Chen
- Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong, China.
- Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, China.
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21
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Bikbov MM, Usubov EL, Oganisyan KK, Lobov SL, Khasanova RR, Dzhemileva LU, Khusnutdinova EK. Genetic aspects of keratoconus development. RUSS J GENET+ 2017. [DOI: 10.1134/s1022795417040020] [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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22
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Karolak JA, Gajecka M. Genomic strategies to understand causes of keratoconus. Mol Genet Genomics 2016; 292:251-269. [PMID: 28032277 PMCID: PMC5357269 DOI: 10.1007/s00438-016-1283-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Accepted: 12/19/2016] [Indexed: 12/12/2022]
Abstract
Keratoconus (KTCN) is a degenerative disorder of the eye characterized by the conical shape and thinning of the cornea. The abnormal structure of KTCN-affected cornea results in loss of visual acuity. While many studies examine how environmental factors influence disease development, finding the genetic triggers has been a major emphasis of KTCN research. This paper focuses on genomic strategies that were implemented for finding candidate genes, including linkage and association studies, and presents different approaches of mutation screening. The advantages and limitations of particular tools are discussed based on literature and personal experience. Since etiology underlying KTCN is complex, numerous findings indicating heterogeneity of genetic factors involved KTCN etiology are presented.
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Affiliation(s)
- Justyna A Karolak
- Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Swiecickiego 4, Poznan, 60-781, Poland.,Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska 32, Poznan, 60-479, Poland
| | - Marzena Gajecka
- Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Swiecickiego 4, Poznan, 60-781, Poland. .,Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska 32, Poznan, 60-479, Poland.
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23
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Bykhovskaya Y, Margines B, Rabinowitz YS. Genetics in Keratoconus: where are we? EYE AND VISION 2016; 3:16. [PMID: 27350955 PMCID: PMC4922054 DOI: 10.1186/s40662-016-0047-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/03/2016] [Indexed: 01/06/2023]
Abstract
Keratoconus (KC) is a non-inflammatory thinning and protrusion of the cornea in which the cornea assumes a conical shape. Complex etiology of this condition at present remains an enigma. Although environmental factors have been involved in KC pathogenesis, strong underlining genetic susceptibility has been proven. The lack of consistent findings among early genetic studies suggested a heterogeneity and complex nature of the genetic contribution to the development of KC. Recently, genome-wide linkage studies (GWLS) and genome-wide association studies (GWAS) were undertaken. Next-generation sequencing (NGS)-based genomic screens are also currently being carried out. Application of these recently developed comprehensive genetic tools led to a much greater success and increased reproducibility of genetic findings in KC. Involvement of the LOX gene identified through GWLS has been confirmed in multiple cohorts of KC patients around the world. KC susceptibility region located at the 2q21.3 chromosomal region near the RAB3GAP1 gene identified through GWAS was independently replicated. Rare variants in the ZNF469 gene (mutated in corneal dystrophy Brittle Cornea Syndrome) and in the TGFBI gene (mutated in multiple corneal epithelial–stromal TGFBI dystrophies) have been repeatedly identified in familial and sporadic KC patients of different ethnicities. Additional comprehensive strategies using quantitative endophenotypes have been successfully employed to bring further understanding to the genetics of KC. Additional genetic determinants including the COL5A1 gene have been identified in the GWAS of KC-related trait central corneal thickness. These recent discoveries confirmed the importance of the endophenotype approach for studying complex genetic diseases such as KC and showed that different connective tissue disorders may have the same genetic determinants.
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Affiliation(s)
- Yelena Bykhovskaya
- Regenerative Medicine Institute and Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, USA ; Cornea Genetic Eye Institute, 50 N. La Cienega Blvd. Suite #340, Beverly Hills, CA 90211 USA
| | - Benjamin Margines
- Cornea Genetic Eye Institute, 50 N. La Cienega Blvd. Suite #340, Beverly Hills, CA 90211 USA
| | - Yaron S Rabinowitz
- Regenerative Medicine Institute and Department of Surgery, Cedars-Sinai Medical Center, Los Angeles, USA ; Cornea Genetic Eye Institute, 50 N. La Cienega Blvd. Suite #340, Beverly Hills, CA 90211 USA ; The Jules Stein Eye Institute, University of California Los Angeles, Los Angeles, USA
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Al-Raddadi HS, Al-Barry MA, Al-Harbi E, Samman MI, Albalawi AM, Basit S. Sequence analysis of the VSX1 and SOD1 genes in families with Keratoconus and a review of the literature. J Taibah Univ Med Sci 2016. [DOI: 10.1016/j.jtumed.2015.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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25
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Moschos MM, Kokolakis N, Gazouli M, Chatziralli IP, Droutsas D, Anagnou NP, Ladas ID. Polymorphism Analysis of VSX1 and SOD1 Genes in Greek Patients with Keratoconus. Ophthalmic Genet 2016; 36:213-7. [PMID: 24099280 DOI: 10.3109/13816810.2013.843712] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND A number of mutations in the VSX1 and SOD1 genes have been reported to be associated with keratoconus (KC), however the results from different studies are controversial. In this study, we conducted the genotyping of common polymorphisms [VSX1: D144E, H244R, R166W, G160D; SOD1: intronic 7-base deletion (c.169 + 50 delTAAACAG)], in a case-control sample panel of the Greek population. MATERIALS AND METHODS A case-control panel, with 33 KC patients and 78 healthy controls, were surveyed. DNA from each individual was tested for the VSX1: D144E, H244R, R166W, G160D and SOD1: intronic 7-base deletion (c.169 + 50 delTAAACAG) polymorphisms by direct sequencing. RESULTS We observed no polymorphisms of the VSX1 gene in the case-control panel. Concerning the SOD1 intronic 7-base deletion (c.169 + 50 delTAAACAG), our findings suggest that heterozygous carriers are over-represented among KC cases compared to healthy controls (p = 0.002). CONCLUSIONS We cannot confirm the previously reported association of the polymorphism in the VSX1 gene with KC. Our results suggest a possible causative role of SOD1 in the pathogenesis of KC. Further studies are required to identify other important genetic factors involved in the pathogenesis and progression of KC.
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Nowak DM, Gajecka M. Nonrandom Distribution of miRNAs Genes and Single Nucleotide Variants in Keratoconus Loci. PLoS One 2015; 10:e0132143. [PMID: 26176855 PMCID: PMC4503774 DOI: 10.1371/journal.pone.0132143] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2015] [Accepted: 06/10/2015] [Indexed: 12/14/2022] Open
Abstract
Despite numerous studies, the causes of both development and progression of keratoconus remain elusive. Previous studies of this disorder focused mainly on one or two genetic factors only. However, in the analysis of such complex diseases all potential factors should be taken into consideration. The purpose of this study was a comprehensive analysis of known keratoconus loci to uncover genetic factors involved in this disease causation in the general population, which could be omitted in the original studies. In this investigation genomic data available in various databases and experimental own data were assessed. The lists of single nucleotide variants and miRNA genes localized in reported keratoconus loci were obtained from Ensembl and miRBase, respectively. The potential impact of nonsynonymous amino acid substitutions on protein structure and function was assessed with PolyPhen-2 and SIFT. For selected protein genes the ranking was made to choose those most promising for keratoconus development. Ranking results were based on topological features in the protein-protein interaction network. High specificity for the populations in which the causative sequence variants have been identified was found. In addition, the possibility of links between previously analyzed keratoconus loci was confirmed including miRNA-gene interactions. Identified number of genes associated with oxidative stress and inflammatory agents corroborated the hypothesis of their effect on the disease etiology. Distribution of the numerous sequences variants within both exons and mature miRNA which forces you to search for a broader look at the determinants of keratoconus. Our findings highlight the complexity of the keratoconus genetics.
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Affiliation(s)
- Dorota M. Nowak
- Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
- Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
| | - Marzena Gajecka
- Department of Genetics and Pharmaceutical Microbiology, Poznan University of Medical Sciences, Poznan, Poland
- Institute of Human Genetics, Polish Academy of Sciences, Poznan, Poland
- * E-mail:
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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: 233] [Impact Index Per Article: 25.9] [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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Dudakova L, Liskova P, Jirsova K. Is copper imbalance an environmental factor influencing keratoconus development? Med Hypotheses 2015; 84:518-24. [PMID: 25758858 DOI: 10.1016/j.mehy.2015.02.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Accepted: 02/25/2015] [Indexed: 12/15/2022]
Affiliation(s)
- L Dudakova
- Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.
| | - P Liskova
- Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic; Department of Ophthalmology, General Teaching Hospital and First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - K Jirsova
- Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
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Abstract
Keratoconus (KC) is the most common ectasia of the cornea and is a common reason for corneal transplant. Therapeutic strategies that can arrest the progression of this disease and modify the underlying pathogenesis are getting more and more popularity among scientists. Cumulating data represent strong evidence of a genetic role in the pathogenesis of KC. Different loci have been identified, and certain mutations have also been mapped for this disease. Moreover, Biophysical properties of the cornea create an appropriate candidate of this tissue for gene therapy. Immune privilege, transparency and ex vivo stability are among these properties. Recent advantage in vectors, besides the ability to modulate the corneal milieu for accepting the target gene for a longer period and fruitful translation, make a big hope for stupendous results reasonable.
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Affiliation(s)
- Mahgol Farjadnia
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad Naderan
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
| | - Mehrdad Mohammadpour
- Eye Research Center, Farabi Eye Hospital, Tehran University of Medical Sciences, Tehran, Iran
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Abu-Amero KK, Al-Muammar AM, Kondkar AA. Genetics of keratoconus: where do we stand? J Ophthalmol 2014; 2014:641708. [PMID: 25254113 PMCID: PMC4164130 DOI: 10.1155/2014/641708] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Revised: 08/07/2014] [Accepted: 08/20/2014] [Indexed: 01/07/2023] Open
Abstract
Keratoconus is a progressive thinning and anterior protrusion of the cornea that results in steepening and distortion of the cornea, altered refractive powers, and reduced vision. Keratoconus has a complex multifactorial etiology, with environmental, behavioral, and multiple genetic components contributing to the disease pathophysiology. Using genome-wide and candidate gene approaches several genomic loci and genes have been identified that highlight the complex molecular etiology of this disease. The review focuses on current knowledge of these genetic risk factors associated with keratoconus.
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Affiliation(s)
- Khaled K. Abu-Amero
- Ophthalmic Genetics Laboratory, Department of Ophthalmology, College of Medicine, King Saud University, P.O. Box 245, Riyadh 11411, Saudi Arabia
- Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, P.O. Box 245, Riyadh 11411, Saudi Arabia
- Department of Ophthalmology, College of Medicine, University of Florida, Jacksonville, FL 32209, USA
| | - Abdulrahman M. Al-Muammar
- Ophthalmic Genetics Laboratory, Department of Ophthalmology, College of Medicine, King Saud University, P.O. Box 245, Riyadh 11411, Saudi Arabia
| | - Altaf A. Kondkar
- Ophthalmic Genetics Laboratory, Department of Ophthalmology, College of Medicine, King Saud University, P.O. Box 245, Riyadh 11411, Saudi Arabia
- Glaucoma Research Chair, Department of Ophthalmology, College of Medicine, King Saud University, P.O. Box 245, Riyadh 11411, Saudi Arabia
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Karolak JA, Polakowski P, Szaflik J, Szaflik JP, Gajecka M. Molecular Screening of Keratoconus Susceptibility Sequence Variants in VSX1, TGFBI, DOCK9, STK24, and IPO5 Genes in Polish Patients and Novel TGFBI Variant Identification. Ophthalmic Genet 2014; 37:37-43. [PMID: 24940934 DOI: 10.3109/13816810.2014.926375] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE Keratoconus (KTCN) is a degenerative disorder of the eye that results in the conical shape and thinning of the cornea and is a leading cause for corneal transplantations. A number of studies suggest that genetic factors play a role in KTCN etiology. Some candidate gene variants have recently been shown to be associated with KTCN. The purpose of our study was to verify the role of VSX1, TGFBI, DOCK9, IPO5, and STK24 sequence variants in Polish KTCN patients. METHODS Forty-two Polish patients with sporadic KTCN and 50 control individuals were enrolled into this study. Both affected and unaffected individuals underwent detailed ophthalmic examination. The mutations screening in the candidate genes was performed by the direct sequencing method. RESULTS Analysis of VSX1, TGFBI, DOCK9, IPO5, and STK24 genes identified numerous sequence variants. Variants c.-264_-255delGGGGTGGGGT, c.627 + 23G > A, c.809-6_809-5insT, and c.*200G > T in the VSX1 gene, and heterozygous c.1598G > A mutation (Arg533Gln) in exon 12 of TGFBI were detected for the first time in KTCN patients. Two known sequence variants of TGFBI c.1620T > C (Phe540Phe) and c.1678 + 23G > A were observed in KTCN patients and control individuals. The newly reported c.717 + 43A > G substitution in intron 7 of DOCK9 was identified in both KTCN patients and healthy individuals. CONCLUSIONS Our investigation showed that KTCN-related sequence variants of analyzed genes were found in a very small proportion of the studied patients indicating that genes other than VSX1, TGFBI, DOCK9, IPO5, and STK24 are involved in the development and progression of KTCN in Polish patients. Our results support the hypothesis about the genetic heterogeneity of KTCN.
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Affiliation(s)
- Justyna A Karolak
- a Department of Genetics and Pharmaceutical Microbiology , Poznan University of Medical Sciences , Poznan , Poland .,b Institute of Human Genetics, Polish Academy of Sciences , Poznan , Poland , and
| | - Piotr Polakowski
- c Department of Ophthalmology , Medical University of Warsaw, SPKSO University Ophthalmic Hospital , Warsaw , Poland
| | - Jerzy Szaflik
- c Department of Ophthalmology , Medical University of Warsaw, SPKSO University Ophthalmic Hospital , Warsaw , Poland
| | - Jacek P Szaflik
- c Department of Ophthalmology , Medical University of Warsaw, SPKSO University Ophthalmic Hospital , Warsaw , Poland
| | - Marzena Gajecka
- b Institute of Human Genetics, Polish Academy of Sciences , Poznan , Poland , and
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Lechner J, Porter LF, Rice A, Vitart V, Armstrong DJ, Schorderet DF, Munier FL, Wright AF, Inglehearn CF, Black GC, Simpson DA, Manson F, Willoughby CE. Enrichment of pathogenic alleles in the brittle cornea gene, ZNF469, in keratoconus. Hum Mol Genet 2014; 23:5527-35. [PMID: 24895405 DOI: 10.1093/hmg/ddu253] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Keratoconus, a common inherited ocular disorder resulting in progressive corneal thinning, is the leading indication for corneal transplantation in the developed world. Genome-wide association studies have identified common SNPs 100 kb upstream of ZNF469 strongly associated with corneal thickness. Homozygous mutations in ZNF469 and PR domain-containing protein 5 (PRDM5) genes result in brittle cornea syndrome (BCS) Types 1 and 2, respectively. BCS is an autosomal recessive generalized connective tissue disorder associated with extreme corneal thinning and a high risk of corneal rupture. Some individuals with heterozygous PRDM5 mutations demonstrate a carrier ocular phenotype, which includes a mildly reduced corneal thickness, keratoconus and blue sclera. We hypothesized that heterozygous variants in PRDM5 and ZNF469 predispose to the development of isolated keratoconus. We found a significant enrichment of potentially pathologic heterozygous alleles in ZNF469 associated with the development of keratoconus (P = 0.00102) resulting in a relative risk of 12.0. This enrichment of rare potentially pathogenic alleles in ZNF469 in 12.5% of keratoconus patients represents a significant mutational load and highlights ZNF469 as the most significant genetic factor responsible for keratoconus identified to date.
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Affiliation(s)
- Judith Lechner
- Centre for Vision and Vascular Science, Queen's University Belfast, Belfast BT12 6BA, UK
| | - Louise F Porter
- Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WU, UK
| | - Aine Rice
- Leeds Institute of Molecular Medicine, St. James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Veronique Vitart
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - David J Armstrong
- Department of Ophthalmology, Royal Victoria Hospital, Belfast BT12 6BA, UK
| | - Daniel F Schorderet
- IRO - Institute for Research in Ophthalmology, Sion, Switzerland Department of Ophthalmology, University of Lausanne, Lausanne, Switzerland Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Francis L Munier
- IRO - Institute for Research in Ophthalmology, Sion, Switzerland Jules-Gonin Eye Hospital, Lausanne, Switzerland
| | - Alan F Wright
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Chris F Inglehearn
- Leeds Institute of Molecular Medicine, St. James's University Hospital, University of Leeds, Leeds LS9 7TF, UK
| | - Graeme C Black
- Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WU, UK
| | - David A Simpson
- Centre for Vision and Vascular Science, Queen's University Belfast, Belfast BT12 6BA, UK
| | - Forbes Manson
- Institute of Human Development, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester M13 9WU, UK
| | - Colin E Willoughby
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool L69 3GA, UK
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Aldave AJ, Ann LB, Frausto RF, Nguyen CK, Yu F, Raber IM. Classification of posterior polymorphous corneal dystrophy as a corneal ectatic disorder following confirmation of associated significant corneal steepening. JAMA Ophthalmol 2014; 131:1583-90. [PMID: 24113819 DOI: 10.1001/jamaophthalmol.2013.5036] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
IMPORTANCE The identification of steep corneal curvatures in a significant percentage of patients with posterior polymorphous corneal dystrophy (PPCD) confirms this previously reported association and suggests a role for the ZEB1 protein in keratocyte function. OBJECTIVE To determine whether PPCD is characterized by significant corneal steepening. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study at university-based and private ophthalmology practices of 38 individuals (27 affected and 11 unaffected) from 23 families with PPCD. EXPOSURE Slitlamp examination and corneal topographic imaging were performed for individuals with PPCD and unaffected family members. Saliva or blood samples were obtained from each individual for DNA isolation and ZEB1 sequencing. Corneal ZEB1 expression was measured using immunohistochemistry. MAIN OUTCOMES AND MEASURES Percentage of individuals affected with PPCD and controls with an average keratometric value greater than 48.0 diopters (D) in each eye; the mean keratometric value averaged for both eyes of individuals with PPCD and controls; and the correlation of ZEB1 mutation with keratometric value. RESULTS ZEB1 coding region mutations were identified in 7 of the 27 affected individuals. Ten of the 38 individuals (26.3%) had average keratometric values greater than 48.0 D OU: 10 of 27 individuals with PPCD (37.0%; 6 of 7 individuals with ZEB1 mutations [85.7%] and 4 of 20 individuals without ZEB1 mutations [20.0%]) and 0 of 11 unaffected individuals (P = .04 for unaffected vs affected individuals; P = .004 for individuals with PPCD with vs without ZEB1 mutation). The mean keratometric value of each eye of affected individuals (48.2 D) was significantly greater than that of each eye of unaffected family members (44.1 D) (P = .03). Affected individuals with ZEB1 mutations demonstrated a mean keratometric value of 53.3 D, which was significantly greater than that of affected individuals without ZEB1 mutations (46.5 D; P = .004). Fluorescence immunohistochemistry demonstrated ZEB1 expression in keratocyte nuclei. CONCLUSIONS AND RELEVANCE Abnormally steep corneal curvatures are identified in 37% of all individuals with PPCD and 86% of affected individuals with PPCD secondary to ZEB1 mutations. ZEB1 is present in keratocyte nuclei, suggesting a role for ZEB1 in keratocyte function. Therefore, ZEB1 may play a role in both corneal stromal and endothelial development and function, and PPCD should be considered both an endothelial dystrophy and an ectatic disorder.
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Affiliation(s)
- Anthony J Aldave
- Jules Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles
| | - Lydia B Ann
- Jules Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles
| | - Ricardo F Frausto
- Jules Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles
| | - Catherine K Nguyen
- Jules Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles
| | - Fei Yu
- Jules Stein Eye Institute, David Geffen School of Medicine at University of California, Los Angeles
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Sutherland JE, Day MA. Advantages and disadvantages of molecular testing in ophthalmology. EXPERT REVIEW OF OPHTHALMOLOGY 2014. [DOI: 10.1586/eop.11.2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Sahebjada S, Schache M, Richardson AJ, Snibson G, Daniell M, Baird PN. Association of the hepatocyte growth factor gene with keratoconus in an Australian population. PLoS One 2014; 9:e84067. [PMID: 24416191 PMCID: PMC3885514 DOI: 10.1371/journal.pone.0084067] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 11/11/2013] [Indexed: 02/08/2023] Open
Abstract
PURPOSE A previous study has indicated suggestive association of the hepatocyte growth factor (HGF) gene with Keratoconus. We wished to assess this association in an independent Caucasian cohort as well as assess its association with corneal curvature. PARTICIPANTS Keratoconus patients were recruited from private and public clinics in Melbourne, Australia. Non-keratoconic individuals were identified from the Genes in Myopia (GEM) study from Australia. A total of 830 individuals were used for the analysis including 157 keratoconic and 673 non keratoconic subjects. METHODS Tag single nucleotide polymorphisms (tSNPs) were chosen to encompass the hepatocyte growth factor gene as well as 2 kb upstream of the start codon through to 2 kb downstream of the stop codon. Logistic and linear regression including age and gender as covariates were applied in statistical analysis with subsequent Bonferroni correction. RESULTS Ten tSNPs were genotyped. Following statistical analysis and multiple testing correction, a statistically significant association was found for the tSNP rs2286194 {p = 1.1×10-(3) Odds Ratio 0.52, 95% CI--0.35, 0.77} for keratoconus. No association was found between the 10 tSNPs and corneal curvature. CONCLUSIONS These findings provide additional evidence of significant association of the HGF gene with Keratoconus. This association does not appear to act through the corneal curvature route.
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Affiliation(s)
- Srujana Sahebjada
- Centre for Eye Research Australia, Melbourne, Australia
- The University of Melbourne, Melbourne, Australia
| | - Maria Schache
- Centre for Eye Research Australia, Melbourne, Australia
| | | | - Grant Snibson
- Centre for Eye Research Australia, Melbourne, Australia
- Royal Victorian Eye and Ear Hospital, Melbourne, Australia
| | - Mark Daniell
- Centre for Eye Research Australia, Melbourne, Australia
| | - Paul N. Baird
- Centre for Eye Research Australia, Melbourne, Australia
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Abstract
Keratoconus (KC) is a common degenerative condition that frequently results in visual loss with an onset typically in early adulthood. It is the single most common reason for keratoplasty in the developed world. The cause and underlying pathological mechanism are unknown, but both environmental and genetic factors are thought to contribute to the development of the disease. Various strategies have been employed to address the gap in our understanding of this complex disease, with the expectation that over time more sophisticated therapies will be developed. In this review we summarise our current knowledge of the aetiology and risk factors associated with KC.
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Verma A, Das M, Srinivasan M, Prajna NV, Sundaresan P. Investigation of VSX1 sequence variants in South Indian patients with sporadic cases of keratoconus. BMC Res Notes 2013; 6:103. [PMID: 23506487 PMCID: PMC3608990 DOI: 10.1186/1756-0500-6-103] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 01/15/2013] [Indexed: 01/17/2023] Open
Abstract
Background The involvement of VSX1 gene for the genetic basis of keratoconus is unclear and controversial. The genetic screening of VSX1 from different ethnic populations can enlighten this subject. The aim of the present study is to investigate the role of VSX1 gene in patients with sporadic cases of keratoconus from South India. Methods The VSX1 gene coding regions, including exon-intron boundaries were screened by direct sequencing analysis in 117 sporadic cases of keratoconus. The identified variations were also analyzed in 108 ethnic matched healthy blood donors. Results In the VSX1 gene screening, no pathogenic mutation was identified, whereas we could find the presence of four reported single nucleotide polymorphisms; c.546A>G (rs12480307), c.627+23G>A (rs6138482), c.627+84T>A (rs56157240) and c.504-24C>T (IVS3-24C). These variations were observed in similar frequency between cases and controls. Conclusions The lack of VSX1 pathogenic variations in a large number of unrelated sporadic keratoconus patients tend to omit its role, and corroborate the involvement of other genetic, environmental or behavioural factors in the development of this complex disorder.
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Affiliation(s)
- Anshuman Verma
- Department of Genetics, Dr. G. Venkataswamy Eye Research Institute, Aravind Medical Research Foundation, Aravind Eye Hospital, Madurai, Tamil Nadu, India
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Abstract
Keratoconus (KC) is one of the leading causes for keratoplasty. While the genetic aetiology of more and more corneal dystrophies is revealed, KC falls behind. And it is not because of lack of effort. The diversity in the many published results from over two decades is discussed in relation to the present knowledge in molecular biology. Results that at first appear to be in conflict with each other make sense when placed in the right context. Ophthalmologists often refer to KC as a heterogeneous disease. This review demonstrates that it truly is a multifactorial disease. Despite the many attempts to reveal the aetiology of KC, the pathological mechanism(s) still remain to be solved.
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Affiliation(s)
- Kim Nielsen
- Department of Ophthalmology, Aarhus University Hospital, Aarhus C, Denmark.
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Dehkordi FA, Rashki A, Bagheri N, Chaleshtori MH, Memarzadeh E, Salehi A, Ghatreh H, Zandi F, Yazdanpanahi N, Tabatabaiefar MA, Chaleshtori MH. Study of VSX1 mutations in patients with keratoconus in southwest Iran using PCR-single-strand conformation polymorphism/heteroduplex analysis and sequencing method. Acta Cytol 2013; 57:646-51. [PMID: 24107477 DOI: 10.1159/000353297] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2013] [Accepted: 05/28/2013] [Indexed: 11/19/2022]
Abstract
OBJECTIVE Keratoconus (KC) is an eye disorder in which the cornea is swollen, thinned and deformed. Despite extensive studies, the pathophysiological processes and genetic etiology of KC are unknown. The disease incidence is approximately 1 in 2,000, and it is the most common cause of corneal transplantation in the USA. Many genes are involved in the disease, but evidence suggests a major role for VSX1 in the etiology of KC. This study aimed to determine the frequency of mutations in exons 2, 3 and 4 of the VSX1 gene in Chaharmahal va Bakhtiari province in the southwest of Iran. STUDY DESIGN In this experimental study, mutations in 3 exons, namely exons 2, 3 and 4, of VSX1 were investigated in 50 patients with KC and 50 healthy control subjects. DNA was extracted using a standard phenol-chloroform method. PCR-single-strand conformational polymorphism/heteroduplex analysis was performed, followed by DNA sequencing to confirm the identified motility shifts. RESULTS H244R mutations were found in 1 patient and also in 1 healthy control subject. Furthermore, 12 polymorphisms were identified in patients with KC and 7 in healthy control subjects [rs6138482 and c.546A>G (rs12480307)]. CONCLUSION Our investigation showed that KC-related VSX1 mutations were found in a very small proportion of the studied patients from Iran. Further investigations on other genes are needed to clarify their roles in KC pathogenesis.
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Kapasi M, Rocha G. Comparison of visual and refractive outcomes following Intacs implantation in keratoconus eyes with central and eccentric cones. Can J Ophthalmol 2012; 47:354-9. [DOI: 10.1016/j.jcjo.2012.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2011] [Revised: 02/14/2012] [Accepted: 03/29/2012] [Indexed: 10/26/2022]
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Joo CK, Rho CR, Mok JW, Lee YJ, Kim DH, Park YK. Epidemiologic and Genetic Studies of Keratoconus Patients in Korea. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2012. [DOI: 10.3341/jkos.2012.53.6.839] [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]
Affiliation(s)
- Choun-Ki Joo
- Department of Ophthalmology and Visual Science, The Catholic University of Korea College of Medicine, Seoul, Korea
- Catholic institute of Visual Science, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Chang Rae Rho
- Department of Ophthalmology and Visual Science, The Catholic University of Korea College of Medicine, Seoul, Korea
- Catholic institute of Visual Science, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Jee Won Mok
- Catholic institute of Visual Science, The Catholic University of Korea College of Medicine, Seoul, Korea
| | - Young Jun Lee
- Catholic institute of Visual Science, The Catholic University of Korea College of Medicine, Seoul, Korea
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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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Czugala M, Karolak JA, Nowak DM, Polakowski P, Pitarque J, Molinari A, Rydzanicz M, Bejjani BA, Yue BYJT, Szaflik JP, Gajecka M. Novel mutation and three other sequence variants segregating with phenotype at keratoconus 13q32 susceptibility locus. Eur J Hum Genet 2011; 20:389-97. [PMID: 22045297 DOI: 10.1038/ejhg.2011.203] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Keratoconus (KTCN), a non-inflammatory corneal disorder characterized by stromal thinning, represents a major cause of corneal transplantations. Genetic and environmental factors have a role in the etiology of this complex disease. Previously reported linkage analysis revealed that chromosomal region 13q32 is likely to contain causative gene(s) for familial KTCN. Consequently, we have chosen eight positional candidate genes in this region: MBNL1, IPO5, FARP1, RNF113B, STK24, DOCK9, ZIC5 and ZIC2, and sequenced all of them in 51 individuals from Ecuadorian KTCN families and 105 matching controls. The mutation screening identified one mutation and three sequence variants showing 100% segregation under a dominant model with KTCN phenotype in one large Ecuadorian family. These substitutions were found in three different genes: c.2262A>C (p.Gln754His) and c.720+43A>G in DOCK9; c.2377-132A>C in IPO5 and c.1053+29G>C in STK24. PolyPhen analyses predicted that c.2262A>C (Gln754His) is possibly damaging for the protein function and structure. Our results suggest that c.2262A>C (p.Gln754His) mutation in DOCK9 may contribute to the KTCN phenotype in the large KTCN-014 family.
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Affiliation(s)
- Marta Czugala
- Institute of Human Genetics, Polish Academy of Sciences, Strzeszynska 32,Poznan, Poland
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Burdon KP, Macgregor S, Bykhovskaya Y, Javadiyan S, Li X, Laurie KJ, Muszynska D, Lindsay R, Lechner J, Haritunians T, Henders AK, Dash D, Siscovick D, Anand S, Aldave A, Coster DJ, Szczotka-Flynn L, Mills RA, Iyengar SK, Taylor KD, Phillips T, Montgomery GW, Rotter JI, Hewitt AW, Sharma S, Rabinowitz YS, Willoughby C, Craig JE. Association of polymorphisms in the hepatocyte growth factor gene promoter with keratoconus. Invest Ophthalmol Vis Sci 2011; 52:8514-9. [PMID: 22003120 DOI: 10.1167/iovs.11-8261] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
PURPOSE Keratoconus is a progressive disorder of the cornea that can lead to severe visual impairment or blindness. Although several genomic regions have been linked to rare familial forms of keratoconus, no genes have yet been definitively identified for common forms of the disease. METHODS Two genome-wide association scans were undertaken in parallel. The first used pooled DNA from an Australian cohort, followed by typing of top-ranked single-nucleotide polymorphisms (SNPs) in individual DNA samples. The second was conducted in individually genotyped patients, and controls from the USA. Tag SNPs around the hepatocyte growth factor (HGF) gene were typed in three additional replication cohorts. Serum levels of HGF protein in normal individuals were assessed with ELISA and correlated with genotype. RESULTS The only SNP observed to be associated in both the pooled discovery and primary replication cohort was rs1014091, located upstream of the HGF gene. The nearby SNP rs3735520 was found to be associated in the individually typed discovery cohort (P = 6.1 × 10(-7)). Genotyping of tag SNPs around HGF revealed association at rs3735520 and rs17501108/rs1014091 in four of the five cohorts. Meta-analysis of all five datasets together yielded suggestive P values for rs3735520 (P = 9.9 × 10(-7)) and rs17501108 (P = 9.9 × 10(-5)). In addition, SNP rs3735520 was found to be associated with serum HGF level in normal individuals (P = 0.036). CONCLUSIONS Taken together, these results implicate genetic variation at the HGF locus with keratoconus susceptibility.
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Affiliation(s)
- Kathryn P Burdon
- Department of Ophthalmology, Flinders University, Flinders Medical Centre, Adelaide, South Australia, Australia.
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