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Bhattacharyya N, Chai N, Hafford-Tear NJ, Sadan AN, Szabo A, Zarouchlioti C, Jedlickova J, Leung SK, Liao T, Dudakova L, Skalicka P, Parekh M, Moghul I, Jeffries AR, Cheetham ME, Muthusamy K, Hardcastle AJ, Pontikos N, Liskova P, Tuft SJ, Davidson AE. Deciphering novel TCF4-driven mechanisms underlying a common triplet repeat expansion-mediated disease. PLoS Genet 2024; 20:e1011230. [PMID: 38713708 DOI: 10.1371/journal.pgen.1011230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2023] [Accepted: 03/19/2024] [Indexed: 05/09/2024] Open
Abstract
Fuchs endothelial corneal dystrophy (FECD) is an age-related cause of vision loss, and the most common repeat expansion-mediated disease in humans characterised to date. Up to 80% of European FECD cases have been attributed to expansion of a non-coding CTG repeat element (termed CTG18.1) located within the ubiquitously expressed transcription factor encoding gene, TCF4. The non-coding nature of the repeat and the transcriptomic complexity of TCF4 have made it extremely challenging to experimentally decipher the molecular mechanisms underlying this disease. Here we comprehensively describe CTG18.1 expansion-driven molecular components of disease within primary patient-derived corneal endothelial cells (CECs), generated from a large cohort of individuals with CTG18.1-expanded (Exp+) and CTG 18.1-independent (Exp-) FECD. We employ long-read, short-read, and spatial transcriptomic techniques to interrogate expansion-specific transcriptomic biomarkers. Interrogation of long-read sequencing and alternative splicing analysis of short-read transcriptomic data together reveals the global extent of altered splicing occurring within Exp+ FECD, and unique transcripts associated with CTG18.1-expansions. Similarly, differential gene expression analysis highlights the total transcriptomic consequences of Exp+ FECD within CECs. Furthermore, differential exon usage, pathway enrichment and spatial transcriptomics reveal TCF4 isoform ratio skewing solely in Exp+ FECD with potential downstream functional consequences. Lastly, exome data from 134 Exp- FECD cases identified rare (minor allele frequency <0.005) and potentially deleterious (CADD>15) TCF4 variants in 7/134 FECD Exp- cases, suggesting that TCF4 variants independent of CTG18.1 may increase FECD risk. In summary, our study supports the hypothesis that at least two distinct pathogenic mechanisms, RNA toxicity and TCF4 isoform-specific dysregulation, both underpin the pathophysiology of FECD. We anticipate these data will inform and guide the development of translational interventions for this common triplet-repeat mediated disease.
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Affiliation(s)
- Nihar Bhattacharyya
- University College London Institute of Ophthalmology, London, United Kingdom
| | - Niuzheng Chai
- University College London Institute of Ophthalmology, London, United Kingdom
| | | | - Amanda N Sadan
- University College London Institute of Ophthalmology, London, United Kingdom
| | - Anita Szabo
- University College London Institute of Ophthalmology, London, United Kingdom
| | | | - Jana Jedlickova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Szi Kay Leung
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Tianyi Liao
- University College London Institute of Ophthalmology, London, United Kingdom
| | - Lubica Dudakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Pavlina Skalicka
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Mohit Parekh
- University College London Institute of Ophthalmology, London, United Kingdom
| | - Ismail Moghul
- University College London Institute of Ophthalmology, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Aaron R Jeffries
- Faculty of Health and Life Sciences, University of Exeter, Exeter, United Kingdom
| | - Michael E Cheetham
- University College London Institute of Ophthalmology, London, United Kingdom
| | | | - Alison J Hardcastle
- University College London Institute of Ophthalmology, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Nikolas Pontikos
- University College London Institute of Ophthalmology, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Stephen J Tuft
- University College London Institute of Ophthalmology, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
| | - Alice E Davidson
- University College London Institute of Ophthalmology, London, United Kingdom
- Moorfields Eye Hospital, London, United Kingdom
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Patterson K, Chong JX, Chung DD, Lisch W, Karp CL, Dreisler E, Lockington D, Rohrbach JM, Garczarczyk-Asim D, Müller T, Tuft SJ, Skalicka P, Wilnai Y, Samra NN, Ibrahim A, Mandel H, Davidson AE, Liskova P, Aldave AJ, Bamshad MJ, Janecke AR. Lisch Epithelial Corneal Dystrophy Is Caused by Heterozygous Loss-of-Function Variants in MCOLN1. Am J Ophthalmol 2024; 258:183-195. [PMID: 37972748 DOI: 10.1016/j.ajo.2023.10.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 10/19/2023] [Accepted: 10/20/2023] [Indexed: 11/19/2023]
Abstract
PURPOSE To report the genetic etiology of Lisch epithelial corneal dystrophy (LECD). DESIGN Multicenter cohort study. METHODS A discovery cohort of 27 individuals with LECD from 17 families, including 7 affected members from the original LECD family, 6 patients from 2 new families and 14 simplex cases, was recruited. A cohort of 6 individuals carrying a pathogenic MCOLN1 (mucolipin 1) variant was reviewed for signs of LECD. Next-generation sequencing or targeted Sanger sequencing were used in all patients to identify pathogenic or likely pathogenic variants and penetrance of variants. RESULTS Nine rare heterozygous MCOLN1 variants were identified in 23 of 27 affected individuals from 13 families. The truncating nature of 7 variants and functional testing of 1 missense variant indicated that they result in MCOLN1 haploinsufficiency. Importantly, in the homozygous and compound-heterozygous state, 4 of 9 LECD-associated variants cause the rare lysosomal storage disorder mucolipidosis IV (MLIV). Autosomal recessive MLIV is a systemic disease and comprises neurodegeneration as well as corneal opacity of infantile-onset with epithelial autofluorescent lysosomal inclusions. However, the 6 parents of 3 patients with MLIV confirmed to carry pathogenic MCOLN1 variants did not have the LECD phenotype, suggesting MCOLN1 haploinsufficiency may be associated with reduced penetrance and variable expressivity. CONCLUSIONS MCOLN1 haploinsufficiency is the major cause of LECD. Based on the overlapping clinical features of corneal epithelial cells with autofluorescent inclusions reported in both LECD and MLIV, it is concluded that some carriers of MCOLN1 haploinsufficiency-causing variants present with LECD.
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Affiliation(s)
- Karynne Patterson
- From the Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA (K.P., M.J.B.)
| | - Jessica X Chong
- Department of Pediatrics and Brotman-Baty Institute for Precision Medicine, University of Washington, Seattle, WA 98195, USA (J.X.C.)
| | - Doug D Chung
- Department of Ophthalmology, Stein Eye Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA (D.D.C., A.J.A.)
| | - Walter Lisch
- Department of Ophthalmology, University Medical Center of the Johannes Gutenberg- University Mainz, 55131 Mainz, Germany (W.L.)
| | - Carol L Karp
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller, School of Medicine, Miami, USA (C.L.K.)
| | - Erling Dreisler
- Independent scholar, N.Jespersensvej 3, DK-2000 Copenhagen, Frederiksberg, Denmark (E.D.)
| | - David Lockington
- Tennent Institute of Ophthalmology, NHS Greater Glasgow and Clyde, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, G12 0YN, UK (D.L.)
| | - Jens M Rohrbach
- Universitäts-Augenklinik, Elfriede-Aulhorn-Str. 7, 72076, Tübingen, Deutschland (J.M.R.)
| | - Dorota Garczarczyk-Asim
- Department of Pediatrics I, Medical University of Innsbruck, 6020 Innsbruck, Austria (D.G.-A., T.M., A.R.J.)
| | - Thomas Müller
- Department of Pediatrics I, Medical University of Innsbruck, 6020 Innsbruck, Austria (D.G.-A., T.M., A.R.J.)
| | - Stephen J Tuft
- Moorfields eye hospital NHS foundation trust, London, UK (S.J.T.); UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK (A.E.D.)
| | - Pavlina Skalicka
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic (P.S., P.L.)
| | - Yael Wilnai
- Genetic Institute, Tel Aviv Sourasky Medical Center, Tel Aviv 6423906, Israel (Y.W.)
| | - Nadra Naser Samra
- Genetic Unit, Sieff hospital, Bar Ilan University Faculty of Medicine, Safed, Israel (N.N.S.)
| | - Ali Ibrahim
- Ophthalmology unit, Maccabi and Clalit Health Services, Magdal Shams Medical center, Golan Heights, Israel (A.I.)
| | - Hanna Mandel
- Pediatric Metabolic Clinic, Sieff hospital, Bar Ilan University Faculty of Medicine, Safed, Israel (H.M.)
| | - Alice E Davidson
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK (A.E.D.)
| | - Petra Liskova
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic (P.S., P.L.); Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic (P.S.,P.L.)
| | - Anthony J Aldave
- Department of Ophthalmology, Stein Eye Institute, David Geffen School of Medicine, UCLA, Los Angeles, CA 90095, USA (D.D.C., A.J.A.)
| | - Michael J Bamshad
- From the Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA (K.P., M.J.B.); Department of Pediatrics and Brotman-Baty Institute for Precision Medicine, University of Washington, Seattle, WA 98195, USA (J.X.C.)
| | - Andreas R Janecke
- Department of Pediatrics I, Medical University of Innsbruck, 6020 Innsbruck, Austria (D.G.-A., T.M., A.R.J.); Division of Human Genetics, Medical University of Innsbruck, 6020 Innsbruck, Austria (A.R.J.).
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Cipriani V, Vestito L, Magavern EF, Jacobsen JO, Arno G, Behr ER, Benson KA, Bertoli M, Bockenhauer D, Bowl MR, Burley K, Chan LF, Chinnery P, Conlon P, Costa M, Davidson AE, Dawson SJ, Elhassan E, Flanagan SE, Futema M, Gale DP, García-Ruiz S, Corcia CG, Griffin HR, Hambleton S, Hicks AR, Houlden H, Houlston RS, Howles SA, Kleta R, Lekkerkerker I, Lin S, Liskova P, Mitchison H, Morsy H, Mumford AD, Newman WG, Neatu R, O'Toole EA, Ong AC, Pagnamenta AT, Rahman S, Rajan N, Robinson PN, Ryten M, Sadeghi-Alavijeh O, Sayer JA, Shovlin CL, Taylor JC, Teltsh O, Tomlinson I, Tucci A, Turnbull C, van Eerde AM, Ware JS, Watts LM, Webster AR, Westbury SK, Zheng SL, Caulfield M, Smedley D. Rare disease gene association discovery from burden analysis of the 100,000 Genomes Project data. medRxiv 2023:2023.12.20.23300294. [PMID: 38196618 PMCID: PMC10775325 DOI: 10.1101/2023.12.20.23300294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
To discover rare disease-gene associations, we developed a gene burden analytical framework and applied it to rare, protein-coding variants from whole genome sequencing of 35,008 cases with rare diseases and their family members recruited to the 100,000 Genomes Project (100KGP). Following in silico triaging of the results, 88 novel associations were identified including 38 with existing experimental evidence. We have published the confirmation of one of these associations, hereditary ataxia with UCHL1 , and independent confirmatory evidence has recently been published for four more. We highlight a further seven compelling associations: hypertrophic cardiomyopathy with DYSF and SLC4A3 where both genes show high/specific heart expression and existing associations to skeletal dystrophies or short QT syndrome respectively; monogenic diabetes with UNC13A with a known role in the regulation of β cells and a mouse model with impaired glucose tolerance; epilepsy with KCNQ1 where a mouse model shows seizures and the existing long QT syndrome association may be linked; early onset Parkinson's disease with RYR1 with existing links to tremor pathophysiology and a mouse model with neurological phenotypes; anterior segment ocular abnormalities associated with POMK showing expression in corneal cells and with a zebrafish model with developmental ocular abnormalities; and cystic kidney disease with COL4A3 showing high renal expression and prior evidence for a digenic or modifying role in renal disease. Confirmation of all 88 associations would lead to potential diagnoses in 456 molecularly undiagnosed cases within the 100KGP, as well as other rare disease patients worldwide, highlighting the clinical impact of a large-scale statistical approach to rare disease gene discovery.
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Liu S, Sadan AN, Muthusamy K, Zarouchlioti C, Jedlickova J, Pontikos N, Thaung C, Hardcastle AJ, Netukova M, Skalicka P, Dudakova L, Bunce C, Tuft SJ, Davidson AE, Liskova P. Phenotype and genotype of concurrent keratoconus and Fuchs endothelial corneal dystrophy. Acta Ophthalmol 2023. [PMID: 36883248 DOI: 10.1111/aos.15654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 02/12/2023] [Accepted: 02/16/2023] [Indexed: 03/09/2023]
Abstract
PURPOSE To characterise the phenotype and genotype of concurrent keratoconus and Fuchs endothelial corneal dystrophy (KC + FECD). METHODS We recruited 20 patients with concurrent KC + FECD for a retrospective observational case series from the United Kingdom and the Czech Republic. We compared eight parameters of corneal shape (Pentacam, Oculus) with two groups of age-matched controls who had either isolated keratoconus (KC) or isolated FECD. We genotyped probands for an intronic triplet TCF4 repeat expansion (CTG18.1) and the ZEB1 variant c.1920G >T p.(Gln640His). RESULTS The median age at diagnosis of patients with KC + FECD was 54 (interquartile range 46 to 66) years, with no evidence of KC progression (median follow-up 84 months, range 12 to 120 months). The mean (standard deviation (SD)) of the minimum corneal thickness, 493 (62.7) μm, was greater than eyes with KC, 458 (51.1) μm, but less than eyes with FECD, 590 (55.6) μm. Seven other parameters of corneal shape were more like KC than FECD. Seven (35%) probands with KC + FECD had a TCF4 repeat expansion of ≥50 compared to five controls with isolated FECD. The average of the largest TCF4 expansion in cases with KC + FECD (46 repeats, SD 36 repeats) was similar to the age-matched controls with isolated FECD (36 repeats, SD 28 repeats; p = 0.299). No patient with KC + FECD harboured the ZEB1 variant. CONCLUSIONS The KC + FECD phenotype is consistent with KC but with superimposed stromal swelling from endothelial disease. The proportion of cases with a TCF4 expansion is similar in concurrent KC + FECD and age-matched controls with isolated FECD.
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Affiliation(s)
- Siyin Liu
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK.,UCL Institute of Ophthalmology, London, UK
| | | | - Kirithika Muthusamy
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | | | - Jana Jedlickova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | | | - Caroline Thaung
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | | | - Magdalena Netukova
- Eye Clinic, Medical Faculty Charles University, Teaching Hospital Kralovske Vinohrady, Prague, Czech Republic
| | - Pavlina Skalicka
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Lubica Dudakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Catey Bunce
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | - Stephen J Tuft
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | | | - Petra Liskova
- UCL Institute of Ophthalmology, London, UK.,Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
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5
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Skalicka P, Jedlickova J, Horinek A, Trkova M, Davidson AE, Tuft SJ, Dudakova L, Liskova P. Snail Track Lesion with Flat Keratometry in Anterior Segment Dysgenesis Caused by a Novel FOXC1 Variant. J Clin Med 2022; 11:jcm11175166. [PMID: 36079096 PMCID: PMC9457150 DOI: 10.3390/jcm11175166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
We report the phenotype of a 15-year-old female patient with anterior segment dysgenesis (ASD) caused by a novel heterozygous loss-of-function FOXC1 variant. The proband underwent an ophthalmic examination as well as a molecular genetic investigation comprising exome sequencing, a single nucleotide polymorphism array to access copy number and Sanger sequencing to exclude non-coding causal variants. There was bilateral mild iris hypoplasia with pupil deformation and iridocorneal adhesions. In addition to these features of ASD, the corneas were flat, with mean keratometry readings of 38.8 diopters in the right eye and 39.5 diopters in the left eye. There was a snail track lesion of the left cornea at the level of the Descemet membrane. The central corneal endothelial cell density was reduced bilaterally at 1964 and 1373 cells/mm2 in the right and left eyes, respectively. Molecular genetic analysis revealed that the proband was a carrier of a novel heterozygous frameshifting variant in FOXC1, c.605del p.(Pro202Argfs*113). Neither parent had this change, suggesting a de novo origin which was supported by paternity testing. We found no possibly pathogenic variants in the other genes associated with posterior corneal dystrophies or ASD. Further studies are warranted to verify whether there is a true association between snail track lesions, corneal flattening, and pathogenic variants in FOXC1.
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Affiliation(s)
- Pavlina Skalicka
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
| | - Jana Jedlickova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
| | - Ales Horinek
- Institute of Biology and Medical Genetics, First Faculty of Medicine, Charles University, Prague and General University Hospital in Prague, 128 08 Prague, Czech Republic
| | | | | | - Stephen J. Tuft
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Lubica Dudakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
| | - Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
- Correspondence: ; Tel.: +420-224-967-139
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Thaung C, Davidson AE. Fuchs endothelial corneal dystrophy: current perspectives on diagnostic pathology and genetics-Bowman Club Lecture. BMJ Open Ophthalmol 2022; 7:bmjophth-2022-001103. [PMID: 36161831 PMCID: PMC9341215 DOI: 10.1136/bmjophth-2022-001103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 07/01/2022] [Indexed: 11/18/2022] Open
Abstract
Fuchs endothelial corneal dystrophy (FECD) was first described over a century ago. Since then, we have learnt much about its clinical manifestations, surgical and non-surgical treatment, microscopic appearance and pathogenesis. Over the past decade, significant advances have been made with respect to our understanding of FECD genetics. This progress now enables us to appreciate that FECD in fact describes multiple entities with distinct underlying genetic causes. For example, an early-onset and rare form of the disease has been attributed to missense mutations in the COL8A2 gene, whereas the vast majority of late-onset cases can be attributed to a non-coding repeat expansion within the TCF4 gene.FECD is one of the most common indications for corneal transplantation. In recent years, attention has turned to alternative treatment techniques that do not depend on donor tissue supply. The design and development of these non-surgical treatment approaches have benefited from increased knowledge of pathogenesis.This review will cover our current knowledge about the histology and genetics of FECD, and how combining these interdisciplinary approaches might may improve diagnostic accuracy and aid the development of therapeutics for this common and visually disabling disease.
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Affiliation(s)
- Caroline Thaung
- Moorfields Eye Hospital, London, UK .,Department of Eye Pathology, University College London Institute of Ophthalmology, London, UK
| | - Alice E Davidson
- University College London Institute of Ophthalmology, London, UK
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Dudakova L, Tuft S, Cheong S, Skalicka P, Jedlickova J, Fichtl M, Hlozanek M, Filous A, Vaneckova M, Vincent AL, Hardcastle AJ, Davidson AE, Liskova P. Novel disease-causing variants and phenotypic features of X-linked megalocornea. Acta Ophthalmol 2022; 100:431-439. [PMID: 34644435 DOI: 10.1111/aos.15022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 08/07/2021] [Accepted: 08/31/2021] [Indexed: 12/31/2022]
Abstract
PURPOSE The aim of the study was to describe the phenotype and molecular genetic causes of X-linked megalocornea (MGC1). We recruited four British, one New Zealand, one Vietnamese and four Czech families. METHODS All probands and three female carriers underwent ocular examination and Sanger sequencing of the CHRDL1 gene. Two of the probands also had magnetic resonance imaging (MRI) of the brain. RESULTS We identified nine pathogenic or likely pathogenic and one variant of uncertain significance in CHRDL1, of which eight are novel. Three probands had ocular findings that have not previously been associated with MGC1, namely pigmentary glaucoma, unilateral posterior corneal vesicles, unilateral keratoconus and unilateral Fuchs heterochromic iridocyclitis. The corneal diameters of the three heterozygous carriers were normal, but two had abnormally thin corneas, and one of these was also diagnosed with unilateral keratoconus. Brain MRI identified arachnoid cysts in both probands, one also had a neuroepithelial cyst, while the second had a midsagittal neurodevelopmental abnormality (cavum septum pellucidum et vergae). CONCLUSION The study expands the spectrum of pathogenic variants and the ocular and brain abnormalities that have been identified in individuals with MGC1. Reduced corneal thickness may represent a mild phenotypic feature in some heterozygous female carriers of CHRDL1 pathogenic variants.
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Affiliation(s)
- Lubica Dudakova
- Research Unit for Rare Diseases Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | | | | | - Pavlina Skalicka
- Research Unit for Rare Diseases Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
- Department of Ophthalmology First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | - Jana Jedlickova
- Research Unit for Rare Diseases Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | - Marek Fichtl
- Department of Ophthalmology First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | - Martin Hlozanek
- Department of Ophthalmology Second Faculty of Medicine Charles University and Motol University Hospital Prague Czech Republic
- Ophthalmology Department Third Faculty of Medicine Charles University and Teaching Hospital Kralovske Vinohrady Prague Czech Republic
| | - Ales Filous
- Department of Ophthalmology Second Faculty of Medicine Charles University and Motol University Hospital Prague Czech Republic
| | - Manuela Vaneckova
- Department of Radiodiagnostics First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | - Andrea L. Vincent
- Department of Ophthalmology New Zealand National Eye Centre University of Auckland Auckland New Zealand
| | | | | | - Petra Liskova
- Research Unit for Rare Diseases Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
- UCL Institute of Ophthalmology London UK
- Department of Ophthalmology First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
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Liskova P, Hafford‐Tear NJ, Skalicka P, Malinka F, Jedlickova J, Ďuďáková Ľ, Pontikos N, Davidson AE, Tuft S. Posterior corneal vesicles are not associated with the genetic variants that cause posterior polymorphous corneal dystrophy. Acta Ophthalmol 2022; 100:e1426-e1430. [PMID: 35174971 DOI: 10.1111/aos.15114] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Accepted: 02/04/2022] [Indexed: 11/27/2022]
Abstract
PURPOSE Posterior corneal vesicles (PCVs) have clinical features that are similar to posterior polymorphous corneal dystrophy (PPCD). To help determine whether there is a shared genetic basis, we screened 38 individuals with PCVs for changes in the three genes identified as causative for PPCD. METHODS We prospectively recruited patients for this study. We examined all individuals clinically, with their first-degree relatives when available. We used a combination of Sanger and exome sequencing to screen regulatory regions of OVOL2 and GRHL2, and the entire ZEB1 coding sequence. RESULTS The median age at examination was 37.5 years (range 4.7-84.0 years), 20 (53%) were male and in 19 (50%) the PCVs were unilateral. Most individuals were discharged to optometric review, but five had follow-up for a median of 12 years (range 5-13 years) with no evidence of progression. In cases with unilateral PCVs, there was statistically significant evidence that the change in the affected eye was associated with a lower endothelial cell density (p = 0.0003), greater central corneal thickness (p = 0.0277) and a steeper mean keratometry (p = 0.0034), but not with a higher keratometric astigmatism or a reduced LogMAR visual acuity. First-degree relatives of 13 individuals were available for examination, and in 3 (23%), PCVs were identified. No possibly pathogenic variants were identified in the PPCD-associated genes screened. CONCLUSION We found no evidence that PCVs share the same genetic background as PPCD. In contrast to PPCD, we confirm that PCVs is a mild, non-progressive condition with no requirement for long-term review. However, subsequent cataract surgery can lead to corneal oedema.
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Affiliation(s)
- Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
- Department of Ophthalmology, First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | | | - Pavlina Skalicka
- Department of Ophthalmology, First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | - Frantisek Malinka
- Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
- Department of Computer Science Czech Technical University in Prague Prague Czech Republic
| | - Jana Jedlickova
- Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | - Ľubica Ďuďáková
- Department of Paediatrics and Inherited Metabolic Disorders First Faculty of Medicine Charles University and General University Hospital in Prague Prague Czech Republic
| | | | | | - Stephen Tuft
- UCL Institute of Ophthalmology London UK
- Moorfields Eye Hospital London UK
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9
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Dudakova L, Skalicka P, Davidson AE, Sadan AN, Chylova M, Jahnova H, Anteneova N, Tesarova M, Honzik T, Liskova P. Should Patients with Kearns-Sayre Syndrome and Corneal Endothelial Failure Be Genotyped for a TCF4 Trinucleotide Repeat, Commonly Associated with Fuchs Endothelial Corneal Dystrophy? Genes (Basel) 2021; 12:genes12121918. [PMID: 34946867 PMCID: PMC8702069 DOI: 10.3390/genes12121918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 11/23/2021] [Accepted: 11/28/2021] [Indexed: 11/29/2022] Open
Abstract
The aim of this study was to describe the ocular phenotype in a case with Kearns-Sayre syndrome (KSS) spectrum and to determine if corneal endothelial cell dysfunction could be attributed to other known distinct genetic causes. Herein, genomic DNA was extracted from blood and exome sequencing was performed. Non-coding gene regions implicated in corneal endothelial dystrophies were screened by Sanger sequencing. In addition, a repeat expansion situated within an intron of TCF4 (termed CTG18.1) was genotyped using the short tandem repeat assay. The diagnosis of KSS spectrum was based on the presence of ptosis, chronic progressive external ophthalmoplegia, pigmentary retinopathy, hearing loss, and muscle weakness, which were further supported by the detection of ~6.5 kb mtDNA deletion. At the age of 33 years, the proband’s best corrected visual acuity was reduced to 0.04 in the right eye and 0.2 in the left eye. Rare ocular findings included marked corneal oedema with central corneal thickness of 824 and 844 µm in the right and left eye, respectively. No pathogenic variants in the genes, which are associated with corneal endothelial dystrophies, were identified. Furthermore, the CTG18.1 genotype was 12/33, which exceeds a previously determined critical threshold for toxic RNA foci appearance in corneal endothelial cells.
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Affiliation(s)
- Lubica Dudakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
| | - Pavlina Skalicka
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
| | - Alice E. Davidson
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.E.D.); (A.N.S.)
- Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Amanda N. Sadan
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.E.D.); (A.N.S.)
| | - Monika Chylova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
| | - Helena Jahnova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
| | - Nicole Anteneova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
| | - Marketa Tesarova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
| | - Tomas Honzik
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
| | - Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic; (L.D.); (P.S.); (M.C.); (H.J.); (N.A.); (M.T.); (T.H.)
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 128 08 Prague, Czech Republic
- UCL Institute of Ophthalmology, London EC1V 9EL, UK; (A.E.D.); (A.N.S.)
- Correspondence: ; Tel.: +420-224-967-139
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10
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Dudakova L, Stranecky V, Piherova L, Palecek T, Pontikos N, Kmoch S, Skalicka P, Vaneckova M, Davidson AE, Liskova P. Non-Penetrance for Ocular Phenotype in Two Individuals Carrying Heterozygous Loss-of-Function ZEB1 Alleles. Genes (Basel) 2021; 12:genes12050677. [PMID: 33946386 PMCID: PMC8146820 DOI: 10.3390/genes12050677] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 04/13/2021] [Accepted: 04/28/2021] [Indexed: 01/16/2023] Open
Abstract
ZEB1 loss-of-function (LoF) alleles are known to cause a rare autosomal dominant disorder—posterior polymorphous corneal dystrophy type 3 (PPCD3). To date, 50 pathogenic LoF variants have been identified as disease-causing and familial studies have indicated that the PPCD3 phenotype is penetrant in approximately 95% of carriers. In this study, we interrogated in-house exomes (n = 3616) and genomes (n = 88) for the presence of putative heterozygous LoF variants in ZEB1. Next, we performed detailed phenotyping in a father and his son who carried a novel LoF c.1279C>T; p.(Glu427*) variant in ZEB1 (NM_030751.6) absent from the gnomAD v.2.1.1 dataset. Ocular examination of the two subjects did not show any abnormalities characteristic of PPCD3. GnomAD (n = 141,456 subjects) was also interrogated for LoF ZEB1 variants, notably 8 distinct heterozygous changes presumed to lead to ZEB1 haploinsufficiency, not reported to be associated with PPCD3, have been identified. The NM_030751.6 transcript has a pLI score ≥ 0.99, indicating extreme intolerance to haploinsufficiency. In conclusion, ZEB1 LoF variants are present in a general population at an extremely low frequency. As PPCD3 can be asymptomatic, the true penetrance of ZEB1 LoF variants remains currently unknown but is likely to be lower than estimated by the familial led approaches adopted to date.
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Affiliation(s)
- Lubica Dudakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08 Prague, Czech Republic; (L.D.); (V.S.); (L.P.); (S.K.); (P.S.)
| | - Viktor Stranecky
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08 Prague, Czech Republic; (L.D.); (V.S.); (L.P.); (S.K.); (P.S.)
| | - Lenka Piherova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08 Prague, Czech Republic; (L.D.); (V.S.); (L.P.); (S.K.); (P.S.)
| | - Tomas Palecek
- Second Department of Medicine—Department of Cardiovascular Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 2, 128 08 Prague, Czech Republic;
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK; (N.P.); (A.E.D.)
| | - Stanislav Kmoch
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08 Prague, Czech Republic; (L.D.); (V.S.); (L.P.); (S.K.); (P.S.)
| | - Pavlina Skalicka
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08 Prague, Czech Republic; (L.D.); (V.S.); (L.P.); (S.K.); (P.S.)
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 2, 128 08 Prague, Czech Republic
| | - Manuela Vaneckova
- Department of Radiology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Katerinska 30, 128 08 Prague, Czech Republic;
| | - Alice E. Davidson
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK; (N.P.); (A.E.D.)
| | - Petra Liskova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08 Prague, Czech Republic; (L.D.); (V.S.); (L.P.); (S.K.); (P.S.)
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK; (N.P.); (A.E.D.)
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 2, 128 08 Prague, Czech Republic
- Correspondence: ; Tel.: +420-22496-7139
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11
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Hardcastle AJ, Liskova P, Bykhovskaya Y, McComish BJ, Davidson AE, Inglehearn CF, Li X, Choquet H, Habeeb M, Lucas SEM, Sahebjada S, Pontikos N, Lopez KER, Khawaja AP, Ali M, Dudakova L, Skalicka P, Van Dooren BTH, Geerards AJM, Haudum CW, Faro VL, Tenen A, Simcoe MJ, Patasova K, Yarrand D, Yin J, Siddiqui S, Rice A, Farraj LA, Chen YDI, Rahi JS, Krauss RM, Theusch E, Charlesworth JC, Szczotka-Flynn L, Toomes C, Meester-Smoor MA, Richardson AJ, Mitchell PA, Taylor KD, Melles RB, Aldave AJ, Mills RA, Cao K, Chan E, Daniell MD, Wang JJ, Rotter JI, Hewitt AW, MacGregor S, Klaver CCW, Ramdas WD, Craig JE, Iyengar SK, O'Brart D, Jorgenson E, Baird PN, Rabinowitz YS, Burdon KP, Hammond CJ, Tuft SJ, Hysi PG. A multi-ethnic genome-wide association study implicates collagen matrix integrity and cell differentiation pathways in keratoconus. Commun Biol 2021; 4:266. [PMID: 33649486 PMCID: PMC7921564 DOI: 10.1038/s42003-021-01784-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 02/02/2021] [Indexed: 12/14/2022] Open
Abstract
Keratoconus is characterised by reduced rigidity of the cornea with distortion and focal thinning that causes blurred vision, however, the pathogenetic mechanisms are unknown. It can lead to severe visual morbidity in children and young adults and is a common indication for corneal transplantation worldwide. Here we report the first large scale genome-wide association study of keratoconus including 4,669 cases and 116,547 controls. We have identified significant association with 36 genomic loci that, for the first time, implicate both dysregulation of corneal collagen matrix integrity and cell differentiation pathways as primary disease-causing mechanisms. The results also suggest pleiotropy, with some disease mechanisms shared with other corneal diseases, such as Fuchs endothelial corneal dystrophy. The common variants associated with keratoconus explain 12.5% of the genetic variance, which shows potential for the future development of a diagnostic test to detect susceptibility to disease.
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Affiliation(s)
- Alison J Hardcastle
- UCL Institute of Ophthalmology, London, UK.
- Moorfields Eye Hospital, NHS Foundation Trust, London, UK.
| | - Petra Liskova
- UCL Institute of Ophthalmology, London, UK
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Yelena Bykhovskaya
- The Cornea Eye Institute, Beverly Hills, CA, USA
- Department of Surgery and Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Bennet J McComish
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | | | - Chris F Inglehearn
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Xiaohui Li
- Institute for Translational Genomics and Population Sciences, The Lundquist Institute for Biomedical Innovation (formerly Los Angeles Biomedical Research Institute) at Harbor-UCLA Medical Center; Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Hélène Choquet
- Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
| | - Mahmoud Habeeb
- Department of Ophthalmology, Erasmus Medical Center GD, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center GD, Rotterdam, The Netherlands
| | - Sionne E M Lucas
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | - Srujana Sahebjada
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Department of Surgery, Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | | | | | - Anthony P Khawaja
- UCL Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, NHS Foundation Trust, London, UK
- NIHR Biomedical Research Centre, Moorfields Eye Hospital, London, UK
| | - Manir Ali
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Lubica Dudakova
- Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Pavlina Skalicka
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Bart T H Van Dooren
- Department of Ophthalmology, Erasmus Medical Center GD, Rotterdam, The Netherlands
- Amphia Hospital, Breda, The Netherlands
| | | | - Christoph W Haudum
- Division of Endocrinology and Diabetology, Endocrinology Lab Platform, Department of Internal Medicine, Medical University of Graz, Graz, Austria
| | - Valeria Lo Faro
- Department of Ophthalmology, University Medical Center Groningen (UMCG), Groningen, the Netherlands
- Department of Ophthalmology, Academic Medical Center, Amsterdam, The Netherlands
| | - Abi Tenen
- Vision Eye Institute, Melbourne, VIC, Australia
- School of Primary and Allied Health Care, Monash University, Melbourne, VIC, Australia
- Melbourne Stem Cell Centre, Melbourne, VIC, 3800, Australia
| | - Mark J Simcoe
- Section of Ophthalmology, School of Life Course Sciences, King's College London, London, UK
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Karina Patasova
- Section of Ophthalmology, School of Life Course Sciences, King's College London, London, UK
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Darioush Yarrand
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
| | - Jie Yin
- Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
| | - Salina Siddiqui
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
- Department of Ophthalmology, St James's University Hospital, Leeds, UK
| | - Aine Rice
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Layal Abi Farraj
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Yii-Der Ida Chen
- Institute for Translational Genomics and Population Sciences, The Lundquist Institute for Biomedical Innovation (formerly Los Angeles Biomedical Research Institute) at Harbor-UCLA Medical Center; Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Jugnoo S Rahi
- UCL Great Ormond Street Hospital Institute of Child Health, London, UK
| | | | | | - Jac C Charlesworth
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
| | | | - Carmel Toomes
- Division of Molecular Medicine, Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Magda A Meester-Smoor
- Department of Ophthalmology, Erasmus Medical Center GD, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center GD, Rotterdam, The Netherlands
| | - Andrea J Richardson
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Paul A Mitchell
- Centre for Vision Research, Department of Ophthalmology, Westmead Institute for Medical Research, University of Sydney, Westmead, NSW, Australia
| | - Kent D Taylor
- Institute for Translational Genomics and Population Sciences, The Lundquist Institute for Biomedical Innovation (formerly Los Angeles Biomedical Research Institute) at Harbor-UCLA Medical Center; Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Ronald B Melles
- Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
| | - Anthony J Aldave
- The Jules Stein Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Richard A Mills
- Department of Ophthalmology, Flinders University, Adelaide, SA, Australia
| | - Ke Cao
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Department of Surgery, Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Elsie Chan
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Department of Surgery, Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Mark D Daniell
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Department of Surgery, Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Jie Jin Wang
- Health Services and Systems Research, Duke-NUS Medical School, Singapore, Singapore
| | - Jerome I Rotter
- Institute for Translational Genomics and Population Sciences, The Lundquist Institute for Biomedical Innovation (formerly Los Angeles Biomedical Research Institute) at Harbor-UCLA Medical Center; Department of Pediatrics, Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Alex W Hewitt
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- Vision Eye Institute, Melbourne, VIC, Australia
- School of Primary and Allied Health Care, Monash University, Melbourne, VIC, Australia
- Melbourne Stem Cell Centre, Melbourne, VIC, 3800, Australia
| | - Stuart MacGregor
- QIMR Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Caroline C W Klaver
- Department of Ophthalmology, Erasmus Medical Center GD, Rotterdam, The Netherlands
- Department of Epidemiology, Erasmus Medical Center GD, Rotterdam, The Netherlands
| | - Wishal D Ramdas
- Department of Ophthalmology, Erasmus Medical Center GD, Rotterdam, The Netherlands
| | - Jamie E Craig
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- Department of Ophthalmology, Flinders University, Adelaide, SA, Australia
| | - Sudha K Iyengar
- Department of Ophthalmology, Case Western Reserve University, Cleveland, OH, USA
| | - David O'Brart
- Section of Ophthalmology, School of Life Course Sciences, King's College London, London, UK
- St Thomas Hospital, Guy's and St. Thomas NHS Trust, London, London, UK
| | - Eric Jorgenson
- Division of Research, Kaiser Permanente Northern California, Oakland, CA, USA
| | - Paul N Baird
- Department of Surgery, Ophthalmology, University of Melbourne, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
| | - Yaron S Rabinowitz
- The Cornea Eye Institute, Beverly Hills, CA, USA
- Department of Surgery and Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Kathryn P Burdon
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS, Australia
- Department of Ophthalmology, Flinders University, Adelaide, SA, Australia
| | - Chris J Hammond
- Section of Ophthalmology, School of Life Course Sciences, King's College London, London, UK
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK
- St Thomas Hospital, Guy's and St. Thomas NHS Trust, London, London, UK
| | - Stephen J Tuft
- UCL Institute of Ophthalmology, London, UK.
- Moorfields Eye Hospital, NHS Foundation Trust, London, UK.
| | - Pirro G Hysi
- Section of Ophthalmology, School of Life Course Sciences, King's College London, London, UK.
- Department of Twin Research and Genetic Epidemiology, King's College London, London, UK.
- UCL Great Ormond Street Hospital Institute of Child Health, London, UK.
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12
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Fautsch MP, Wieben ED, Baratz KH, Bhattacharyya N, Sadan AN, Hafford-Tear NJ, Tuft SJ, Davidson AE. TCF4-mediated Fuchs endothelial corneal dystrophy: Insights into a common trinucleotide repeat-associated disease. Prog Retin Eye Res 2020; 81:100883. [PMID: 32735996 PMCID: PMC7988464 DOI: 10.1016/j.preteyeres.2020.100883] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/24/2020] [Accepted: 07/04/2020] [Indexed: 12/13/2022]
Abstract
Fuchs endothelial corneal dystrophy (FECD) is a common cause for heritable visual loss in the elderly. Since the first description of an association between FECD and common polymorphisms situated within the transcription factor 4 (TCF4) gene, genetic and molecular studies have implicated an intronic CTG trinucleotide repeat (CTG18.1) expansion as a causal variant in the majority of FECD patients. To date, several non-mutually exclusive mechanisms have been proposed that drive and/or exacerbate the onset of disease. These mechanisms include (i) TCF4 dysregulation; (ii) toxic gain-of-function from TCF4 repeat-containing RNA; (iii) toxic gain-of-function from repeat-associated non-AUG dependent (RAN) translation; and (iv) somatic instability of CTG18.1. However, the relative contribution of these proposed mechanisms in disease pathogenesis is currently unknown. In this review, we summarise research implicating the repeat expansion in disease pathogenesis, define the phenotype-genotype correlations between FECD and CTG18.1 expansion, and provide an update on research tools that are available to study FECD as a trinucleotide repeat expansion disease. Furthermore, ongoing international research efforts to develop novel CTG18.1 expansion-mediated FECD therapeutics are highlighted and we provide a forward-thinking perspective on key unanswered questions that remain in the field. FECD is a common, age-related corneal dystrophy. The majority of cases are associated with expansion of a CTG repeat (CTG18.1). FECD is the most common trinucleotide repeat expansion disease in humans. Evidence supports multiple molecular mechanisms underlying the pathophysiology. Novel CTG18.1-targeted therapeutics are in development.
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Affiliation(s)
- Michael P Fautsch
- Department of Ophthalmology, 200 1st St SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | - Eric D Wieben
- Department of Biochemistry and Molecular Biology, 200 1st St SW, Mayo Clinic, Rochester, MN, USA.
| | - Keith H Baratz
- Department of Ophthalmology, 200 1st St SW, Mayo Clinic, Rochester, MN, 55905, USA.
| | | | - Amanda N Sadan
- University College London Institute of Ophthalmology, London, ECIV 9EL, UK.
| | | | - Stephen J Tuft
- University College London Institute of Ophthalmology, London, ECIV 9EL, UK; Moorfields Eye Hospital, London, EC1V 2PD, UK.
| | - Alice E Davidson
- University College London Institute of Ophthalmology, London, ECIV 9EL, UK.
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13
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Brejchova K, Dudakova L, Skalicka P, Dobrovolny R, Masek P, Putzova M, Moosajee M, Tuft SJ, Davidson AE, Liskova P. IPSC-Derived Corneal Endothelial-like Cells Act as an Appropriate Model System to Assess the Impact of SLC4A11 Variants on Pre-mRNA Splicing. Invest Ophthalmol Vis Sci 2019; 60:3084-3090. [PMID: 31323090 PMCID: PMC6645617 DOI: 10.1167/iovs.19-26930] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Purpose To report molecular genetic findings in six probands with congenital hereditary endothelial dystrophy (CHED) variably associated with hearing loss (also known as Harboyan syndrome). Furthermore, we developed a cellular model to determine if disease-associated variants induce aberrant SLC4A11 pre-mRNA splicing. Methods Direct sequencing of the entire SLC4A11 coding region was performed in five probands. In one individual, whole genome sequencing was undertaken. The effect of c.2240+5G>A on pre-mRNA splicing was evaluated in a corneal endothelial-like (CE-like) cell model expressing SLC4A11. CE-like cells were derived from autologous induced pluripotent stem cells (iPSCs) via neural crest cells exposed to B27, PDGF-BB, and DKK-2. Total RNA was extracted, and RT-PCR was performed followed by Sanger and a targeted next generation sequencing (NGS) approach to identify and quantify the relative abundance of alternatively spliced transcripts. Results In total, 11 different mutations in SLC4A11 evaluated as pathogenic were identified; of these, c.1237G>A, c.2003T>C, c.1216+1G>A, and c.2240+5G>A were novel. The c.2240+5G>A variant was demonstrated to result in aberrant pre-mRNA splicing. A targeted NGS approach confirmed that the variant introduces a leaky cryptic splice donor site leading to the production of a transcript containing an insertion of six base pairs with the subsequent introduction of a premature stop codon (p.Thr747*). Furthermore, a subset of transcripts comprising full retention of intron 16 also were observed, leading to the same functionally null allele. Conclusions This proof-of-concept study highlights the potential of using CE-like cells to investigate the pathogenic consequences of SLC4A11 disease–associated variants.
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Affiliation(s)
- Kristyna Brejchova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Lubica Dudakova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Pavlina Skalicka
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Robert Dobrovolny
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic
| | - Petr Masek
- Clinic of Ophthalmology, University Hospital Ostrava, Ostrava, Czech Republic.,Department of Craniofacial Surgery, University of Ostrava, Ostrava, Czech Republic
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom.,Great Ormond Street Hospital for Children, London, United Kingdom
| | - Stephen J Tuft
- UCL Institute of Ophthalmology, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | | | - Petra Liskova
- Research Unit for Rare Diseases, Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic.,UCL Institute of Ophthalmology, London, United Kingdom
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14
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Khawaja AP, Rojas Lopez KE, Hardcastle AJ, Hammond CJ, Liskova P, Davidson AE, Gore DM, Hafford Tear NJ, Pontikos N, Hayat S, Wareham N, Khaw KT, Tuft SJ, Foster PJ, Hysi PG. Genetic Variants Associated With Corneal Biomechanical Properties and Potentially Conferring Susceptibility to Keratoconus in a Genome-Wide Association Study. JAMA Ophthalmol 2019; 137:1005-1012. [PMID: 31246245 DOI: 10.1001/jamaophthalmol.2019.2058] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Importance Keratoconus is an important cause of visual loss in young adults, but little is known about its genetic causes. Understanding the genetic determinants of corneal biomechanical factors may in turn teach us about keratoconus etiology. Objectives To identify genetic associations with corneal biomechanical properties and to examine whether these genetic variants are associated with keratoconus. Design, Setting, and Participants A stage 1 discovery and replication genome-wide association study (GWAS) of corneal biomechanical properties was performed in 2 cross-sectional populations (6645 participants from the European Prospective Investigation into Cancer and Nutrition [EPIC]-Norfolk Eye Study and 2384 participants from the TwinsUK study). In stage 2, the association of genetic determinants identified in stage 1 with keratoconus was examined in a case-control study. A total of 752 patients with keratoconus were compared with 974 TwinsUK participants (undergoing direct sequencing) or 13 828 EPIC-Norfolk participants (undergoing genotyping and imputation) who were not part of the stage 1 analysis. Data were collected from March 1, 1993, through March 13, 2017, and analyzed from November 1, 2015, through February 1, 2018. Exposures In stage 1, allele dosage at genome-wide single-nucleotide polymorphisms (SNPs); in stage 2, allele dosage at SNPs with genome-wide significance (P < 5 × 10-8) in stage 1 and not previously reported as associated with corneal disease. Main Outcomes and Measures In stage 1, corneal hysteresis (CH) and corneal resistance factor (CRF), measured with the Ocular Response Analyzer (ORA); in stage 2, association with keratoconus compared with controls. Results Among 6645 participants in the discovery cohort (3635 women (54.7%); mean age, 69 years [range, 48-92 years]), 7 genome-wide significant loci associated with CH or CRF were identified that were independently replicated. Two further suggestive loci were identified after meta-analysis. To date, 5 of the identified loci, at ANAPC1, ADAMTS8, ADAMTS17, ABCA6, and COL6A1, have not previously been reported as associated with corneal disease. The ABCA6 locus (rs77542162) was associated with keratoconus using the TwinsUK (odds ratio [OR], 0.50; 95% CI, 0.27-0.92; P = .03) and EPIC-Norfolk controls (OR, 0.39; 95% CI, 0.22-0.70; P = .002). The other loci were associated with keratoconus using TwinsUK (OR per effect allele for ADAMTS8, 0.51 [95% CI, 0.37-0.71; P = 7.9 × 10-5]; for COL6A1, 1.65 [95% CI, 1.05-2.59; P = .03]) or EPIC-Norfolk (OR per effect allele for ANAPC1, 0.78 [95% CI, 0.68-0.89; P = 3.7 × 10-4]; for ADAMTS17, 0.82 [95% CI, 0.68-0.99; P = .04]) controls. Conclusions and Relevance Five loci that are associated with corneal biomechanical properties and that have suggestive associations with keratoconus were reported. These findings suggest the role of type VI collagen, extracellular matrix, and connective-tissue development for corneal biomechanics and keratoconus and the role of CH and CRF as biomarkers for keratoconus.
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Affiliation(s)
- Anthony P Khawaja
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom.,National Institute of Health Research Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and University College London, London, United Kingdom
| | | | | | - Chris J Hammond
- Department of Ophthalmology, King's College London, St Thomas' Hospital, London, United Kingdom
| | - Petra Liskova
- UCL Institute of Ophthalmology, University College London, London, England
| | - Alice E Davidson
- UCL Institute of Ophthalmology, University College London, London, England
| | - Daniel M Gore
- National Institute of Health Research Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and University College London, London, United Kingdom
| | | | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, London, England
| | - Shabina Hayat
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom
| | - Nick Wareham
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom
| | - Kay-Tee Khaw
- Department of Public Health and Primary Care, University of Cambridge, Cambridge, United Kingdom
| | - Stephen J Tuft
- National Institute of Health Research Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and University College London, London, United Kingdom
| | - Paul J Foster
- National Institute of Health Research Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and University College London, London, United Kingdom
| | - Pirro G Hysi
- Department of Ophthalmology, King's College London, St Thomas' Hospital, London, United Kingdom
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15
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Hafford-Tear NJ, Tsai YC, Sadan AN, Sanchez-Pintado B, Zarouchlioti C, Maher GJ, Liskova P, Tuft SJ, Hardcastle AJ, Clark TA, Davidson AE. CRISPR/Cas9-targeted enrichment and long-read sequencing of the Fuchs endothelial corneal dystrophy-associated TCF4 triplet repeat. Genet Med 2019; 21:2092-2102. [PMID: 30733599 PMCID: PMC6752322 DOI: 10.1038/s41436-019-0453-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Accepted: 01/24/2019] [Indexed: 12/15/2022] Open
Abstract
PURPOSE To demonstrate the utility of an amplification-free long-read sequencing method to characterize the Fuchs endothelial corneal dystrophy (FECD)-associated intronic TCF4 triplet repeat (CTG18.1). METHODS We applied an amplification-free method, utilizing the CRISPR/Cas9 system, in combination with PacBio single-molecule real-time (SMRT) long-read sequencing, to study CTG18.1. FECD patient samples displaying a diverse range of CTG18.1 allele lengths and zygosity status (n = 11) were analyzed. A robust data analysis pipeline was developed to effectively filter, align, and interrogate CTG18.1-specific reads. All results were compared with conventional polymerase chain reaction (PCR)-based fragment analysis. RESULTS CRISPR-guided SMRT sequencing of CTG18.1 provided accurate genotyping information for all samples and phasing was possible for 18/22 alleles sequenced. Repeat length instability was observed for all expanded (≥50 repeats) phased CTG18.1 alleles analyzed. Furthermore, higher levels of repeat instability were associated with increased CTG18.1 allele length (mode length ≥91 repeats) indicating that expanded alleles behave dynamically. CONCLUSION CRISPR-guided SMRT sequencing of CTG18.1 has revealed novel insights into CTG18.1 length instability. Furthermore, this study provides a framework to improve the molecular diagnostic accuracy for CTG18.1-mediated FECD, which we anticipate will become increasingly important as gene-directed therapies are developed for this common age-related and sight threatening disease.
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Affiliation(s)
| | | | | | | | | | - Geoffrey J Maher
- Clinical Genetics Group, MRC Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Petra Liskova
- UCL Institute of Ophthalmology, London, UK
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, Prague, Czech Republic
| | - Stephen J Tuft
- UCL Institute of Ophthalmology, London, UK
- Moorfields Eye Hospital, London, UK
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16
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Davidson AE, Hafford-Tear NJ, Dudakova L, Sadan AN, Pontikos N, Hardcastle AJ, Tuft SJ, Liskova P. CUGC for posterior polymorphous corneal dystrophy (PPCD). Eur J Hum Genet 2019; 28:126-131. [PMID: 31201376 DOI: 10.1038/s41431-019-0448-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/23/2019] [Accepted: 05/31/2019] [Indexed: 11/09/2022] Open
Abstract
Name of the disease (synonyms) CUGC for posterior polymorphous corneal dystrophy (PPCD).OMIM# of the disease 122000; 609141; 618031.Name of the analysed genes or DNA/chromosome segments OVOL2 (PPCD1); ZEB1 (PPCD3); GRHL2 (PPCD4).OMIM# of the gene(s) 616441; 189909; 608576. Review of the analytical and clinical validity as well as of the clinical utility of DNA-based testing for variants in theOVOL2, ZEB1andGRHL2gene(s) in a diagnostic setting, predictive and parental settings and for risk assesment in relatives.
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Affiliation(s)
| | | | - Lubica Dudakova
- First Faculty of Medicine, Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08, Prague 2, Czech Republic
| | | | | | | | - Stephen J Tuft
- UCL Institute of Ophthalmology, London, EC1V 9EL, UK.,Moorfields Eye Hospital, London, EC1V 2PD, UK
| | - Petra Liskova
- First Faculty of Medicine, Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, 128 08, Prague 2, Czech Republic
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17
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Zarouchlioti C, Sanchez-Pintado B, Hafford Tear NJ, Klein P, Liskova P, Dulla K, Semo M, Vugler AA, Muthusamy K, Dudakova L, Levis HJ, Skalicka P, Hysi P, Cheetham ME, Tuft SJ, Adamson P, Hardcastle AJ, Davidson AE. Antisense Therapy for a Common Corneal Dystrophy Ameliorates TCF4 Repeat Expansion-Mediated Toxicity. Am J Hum Genet 2018; 102:528-539. [PMID: 29526280 PMCID: PMC5985359 DOI: 10.1016/j.ajhg.2018.02.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 02/14/2018] [Indexed: 12/12/2022] Open
Abstract
Fuchs endothelial corneal dystrophy (FECD) is a common disease for which corneal transplantation is the only treatment option in advanced stages, and alternative treatment strategies are urgently required. Expansion (≥50 copies) of a non-coding trinucleotide repeat in TCF4 confers >76-fold risk for FECD in our large cohort of affected individuals. An FECD subject-derived corneal endothelial cell (CEC) model was developed to probe disease mechanism and investigate therapeutic approaches. The CEC model demonstrated that the repeat expansion leads to nuclear RNA foci, with the sequestration of splicing factor proteins (MBNL1 and MBNL2) to the foci and altered mRNA processing. Antisense oligonucleotide (ASO) treatment led to a significant reduction in the incidence of nuclear foci, MBNL1 recruitment to the foci, and downstream aberrant splicing events, suggesting functional rescue. This proof-of-concept study highlights the potential of a targeted ASO therapy to treat the accessible and tractable corneal tissue affected by this repeat expansion-mediated disease.
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Affiliation(s)
| | | | | | - Pontus Klein
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
| | - Petra Liskova
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic; Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U nemocnice 2, Prague, Czech Republic
| | - Kalyan Dulla
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
| | - Ma'ayan Semo
- UCL Institute of Ophthalmology, London ECIV 9EL, UK
| | | | - Kirithika Muthusamy
- UCL Institute of Ophthalmology, London ECIV 9EL, UK; Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Lubica Dudakova
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic
| | - Hannah J Levis
- Institute of Aging and Chronic Disease, University of Liverpool, Liverpool L7 8TX, UK
| | - Pavlina Skalicka
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic; Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U nemocnice 2, Prague, Czech Republic
| | - Pirro Hysi
- Department of Ophthalmology and Twin Research, King's College London, London SE1 7EH, UK
| | | | - Stephen J Tuft
- UCL Institute of Ophthalmology, London ECIV 9EL, UK; Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Peter Adamson
- ProQR Therapeutics, Zernikedreef 9, 2333 CK Leiden, the Netherlands
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18
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Liskova P, Dudakova L, Evans CJ, Rojas Lopez KE, Pontikos N, Athanasiou D, Jama H, Sach J, Skalicka P, Stranecky V, Kmoch S, Thaung C, Filipec M, Cheetham ME, Davidson AE, Tuft SJ, Hardcastle AJ. Ectopic GRHL2 Expression Due to Non-coding Mutations Promotes Cell State Transition and Causes Posterior Polymorphous Corneal Dystrophy 4. Am J Hum Genet 2018; 102:447-459. [PMID: 29499165 PMCID: PMC5985340 DOI: 10.1016/j.ajhg.2018.02.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 02/02/2018] [Indexed: 12/11/2022] Open
Abstract
In a large family of Czech origin, we mapped a locus for an autosomal-dominant corneal endothelial dystrophy, posterior polymorphous corneal dystrophy 4 (PPCD4), to 8q22.3-q24.12. Whole-genome sequencing identified a unique variant (c.20+544G>T) in this locus, within an intronic regulatory region of GRHL2. Targeted sequencing identified the same variant in three additional previously unsolved PPCD-affected families, including a de novo occurrence that suggests this is a recurrent mutation. Two further unique variants were identified in intron 1 of GRHL2 (c.20+257delT and c.20+133delA) in unrelated PPCD-affected families. GRHL2 is a transcription factor that suppresses epithelial-to-mesenchymal transition (EMT) and is a direct transcriptional repressor of ZEB1. ZEB1 mutations leading to haploinsufficiency cause PPCD3. We previously identified promoter mutations in OVOL2, a gene not normally expressed in the corneal endothelium, as the cause of PPCD1. OVOL2 drives mesenchymal-to-epithelial transition (MET) by directly inhibiting EMT-inducing transcription factors, such as ZEB1. Here, we demonstrate that the GRHL2 regulatory variants identified in PPCD4-affected individuals induce increased transcriptional activity in vitro. Furthermore, although GRHL2 is not expressed in corneal endothelial cells in control tissue, we detected GRHL2 in the corneal "endothelium" in PPCD4 tissue. These cells were also positive for epithelial markers E-Cadherin and Cytokeratin 7, indicating they have transitioned to an epithelial-like cell type. We suggest that mutations inducing MET within the corneal endothelium are a convergent pathogenic mechanism leading to dysfunction of the endothelial barrier and disease.
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Affiliation(s)
- Petra Liskova
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic; Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 2, Prague 128 08, Czech Republic; UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK.
| | - Lubica Dudakova
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic
| | - Cerys J Evans
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Karla E Rojas Lopez
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Dimitra Athanasiou
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Hodan Jama
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Josef Sach
- Institute of Pathology, Third Faculty of Medicine, Charles University, Faculty Hospital Kralovske Vinohrady, Srobarova 50, Prague 100 34, Czech Republic
| | - Pavlina Skalicka
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic; Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 2, Prague 128 08, Czech Republic
| | - Viktor Stranecky
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic
| | - Stanislav Kmoch
- Research Unit for Rare Diseases, Department of Paediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University and General University Hospital in Prague, Ke Karlovu 2, Prague 128 08, Czech Republic
| | - Caroline Thaung
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK; Moorfields Eye Hospital, London EC1V 2PD, UK
| | - Martin Filipec
- Department of Ophthalmology, First Faculty of Medicine, Charles University and General University Hospital in Prague, U Nemocnice 2, Prague 128 08, Czech Republic
| | - Michael E Cheetham
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Alice E Davidson
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | | | - Alison J Hardcastle
- UCL Institute of Ophthalmology, University College London, London EC1V 9EL, UK; Moorfields Eye Hospital, London EC1V 2PD, UK.
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19
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Evans CJ, Davidson AE, Carnt N, Rojas López KE, Veli N, Thaung CM, Tuft SJ, Hardcastle AJ. Genotype-Phenotype Correlation for TGFBI Corneal Dystrophies Identifies p.(G623D) as a Novel Cause of Epithelial Basement Membrane Dystrophy. Invest Ophthalmol Vis Sci 2017; 57:5407-5414. [PMID: 27737463 DOI: 10.1167/iovs.16-19818] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The majority of anterior corneal dystrophies are caused by dominant mutations in TGFBI (transforming growth factor β-induced) collectively known as the epithelial-stromal TGFBI dystrophies. Most cases of epithelial basement membrane dystrophy (EBMD) are thought to result from a degenerative (nongenetic) process; however, a minority of cases are associated with specific TGFBI mutations. We evaluated the spectrum of TGFBI mutations and associated phenotypes in a United Kingdom cohort with typical epithelial-stromal TGFBI dystrophies and an EBMD cohort. Methods We recruited 68 probands with a clinical diagnosis of epithelial-stromal TGFBI dystrophy and 23 probands with bilateral EBMD. DNA was extracted from peripheral leukocytes, and TGFBI was bi-directly Sanger sequenced. Results Nine TGFBI mutations were identified. The most common occurred at the mutation hot-spot residues R124 and R555 in 61 probands; these individuals had a genotype-phenotype correlation consistent with prior reports. Four probands with lattice corneal dystrophy carried a mutation in exon 14: p.(A620D), p.(V625D), and p.(H626R). We identified a p.(G623D) mutation in five probands, including two probands from the EBMD cohort. These subjects typically had an onset of severe recurrent corneal epithelial erosion in the fourth decade with mild diffuse or geographic subepithelial corneal opacities and only small anterior stromal lattice structures in older individuals. Symptoms of painful epithelial erosion improved markedly following phototherapeutic keratectomy. Conclusions There was a strong correlation between genotype and phenotype for the majority of TGFBI mutations. In this cohort, the p.(G623D) mutation caused a greater proportion of TGFBI-associated disease than anticipated, associated with variable phenotypes including individuals diagnosed with EBMD.
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Affiliation(s)
- Cerys J Evans
- University College London (UCL), Institute of Ophthalmology, London, United Kingdom
| | - Alice E Davidson
- University College London (UCL), Institute of Ophthalmology, London, United Kingdom
| | - Nicole Carnt
- Moorfields Eye Hospital, London, United Kingdom 3Save Sight Institute, The University of Sydney, Sydney, New South Wales, Australia
| | - Karla E Rojas López
- University College London (UCL), Institute of Ophthalmology, London, United Kingdom
| | - Neyme Veli
- Moorfields Eye Hospital, London, United Kingdom
| | - Caroline M Thaung
- University College London (UCL), Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom
| | - Stephen J Tuft
- University College London (UCL), Institute of Ophthalmology, London, United Kingdom 2Moorfields Eye Hospital, London, United Kingdom
| | - Alison J Hardcastle
- University College London (UCL), Institute of Ophthalmology, London, United Kingdom
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20
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Bellingham J, Davidson AE, Aboshiha J, Simonelli F, Bainbridge JW, Michaelides M, van der Spuy J. Investigation of Aberrant Splicing Induced byAIPL1Variations as a Cause of Leber Congenital Amaurosis. ACTA ACUST UNITED AC 2015; 56:7784-7793. [DOI: 10.1167/iovs.15-18092] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
| | | | - Jonathan Aboshiha
- UCL Institute of Ophthalmology London, United Kingdom 2Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Second University of Naples, Naples, Italy
| | - James W. Bainbridge
- UCL Institute of Ophthalmology London, United Kingdom 2Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Michel Michaelides
- UCL Institute of Ophthalmology London, United Kingdom 2Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
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21
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Liskova P, Evans CJ, Davidson AE, Zaliova M, Dudakova L, Trkova M, Stranecky V, Carnt N, Plagnol V, Vincent AL, Tuft SJ, Hardcastle AJ. Heterozygous deletions at the ZEB1 locus verify haploinsufficiency as the mechanism of disease for posterior polymorphous corneal dystrophy type 3. Eur J Hum Genet 2015; 24:985-91. [PMID: 26508574 DOI: 10.1038/ejhg.2015.232] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 09/25/2015] [Accepted: 09/30/2015] [Indexed: 11/09/2022] Open
Abstract
A substantial proportion of patients with posterior polymorphous corneal dystrophy (PPCD) lack a molecular diagnosis. We evaluated 14 unrelated probands who had a clinical diagnosis of PPCD who were previously determined to be negative for mutations in ZEB1 by direct sequencing. A combination of techniques was used including whole-exome sequencing (WES), single-nucleotide polymorphism (SNP) array copy number variation (CNV) analysis, quantitative real-time PCR, and long-range PCR. Segregation of potentially pathogenic changes with disease was confirmed, where possible, in family members. A putative run of homozygosity on chromosome 10 was identified by WES in a three-generation PPCD family, suggestive of a heterozygous deletion. SNP array genotyping followed by long-range PCR and direct sequencing to define the breakpoints confirmed the presence of a large deletion that encompassed multiple genes, including ZEB1. Identification of a heterozygous deletion spanning ZEB1 prompted us to further investigate potential CNVs at this locus in the remaining probands, leading to detection of two additional heterozygous ZEB1 gene deletions. This study demonstrates that ZEB1 mutations account for a larger proportion of PPCD than previously estimated, and supports the hypothesis that haploinsufficiency of ZEB1 is the underlying molecular mechanism of disease for PPCD3.
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Affiliation(s)
- Petra Liskova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic.,Department of Ophthalmology, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic
| | | | | | - Marketa Zaliova
- Department of Pediatric Hematology and Oncology, Second Faculty of Medicine, University Hospital Motol, Charles University in Prague, Prague, Czech Republic
| | - Lubica Dudakova
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic
| | - Marie Trkova
- Gennet, Centre for Fetal Medicine and Reproductive Genetics, Prague, Czech Republic
| | - Viktor Stranecky
- Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital, Prague, Czech Republic
| | - Nicole Carnt
- UCL Institute of Ophthalmology, London, UK.,Moorfields Eye Hospital, London, UK
| | | | - Andrea L Vincent
- Department of Ophthalmology, New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
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22
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Gardner JC, Liew G, Quan YH, Ermetal B, Ueyama H, Davidson AE, Schwarz N, Kanuga N, Chana R, Maher ER, Webster AR, Holder GE, Robson AG, Cheetham ME, Liebelt J, Ruddle JB, Moore AT, Michaelides M, Hardcastle AJ. Three different cone opsin gene array mutational mechanisms with genotype-phenotype correlation and functional investigation of cone opsin variants. Hum Mutat 2015; 35:1354-62. [PMID: 25168334 PMCID: PMC4285181 DOI: 10.1002/humu.22679] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Accepted: 08/18/2014] [Indexed: 11/22/2022]
Abstract
Mutations in the OPN1LW (L-) and OPN1MW (M-)cone opsin genes underlie a spectrum of cone photoreceptor defects from stationary loss of color vision to progressive retinal degeneration. Genotypes of 22 families with a range of cone disorders were grouped into three classes: deletions of the locus control region (LCR); missense mutation (p.Cys203Arg) in an L-/M-hybrid gene; and exon 3 single-nucleotide polymorphism (SNP) interchange haplotypes in an otherwise normal gene array. Moderate-to-high myopia was observed in all mutation categories. Individuals with LCR deletions or p.Cys203Arg mutations were more likely to have nystagmus and poor vision, with disease progression in some p.Cys203Arg patients. Three disease-associated exon 3 SNP haplotypes encoding LIAVA, LVAVA, or MIAVA were identified in our cohort. These patients were less likely to have nystagmus but more likely to show progression, with all patients over the age of 40 years having marked macular abnormalities. Previously, the haplotype LIAVA has been shown to result in exon 3 skipping. Here, we show that haplotypes LVAVA and MIAVA also result in aberrant splicing, with a residual low level of correctly spliced cone opsin. The OPN1LW/OPN1MW:c.532A>G SNP, common to all three disease-associated haplotypes, appears to be principally responsible for this mutational mechanism.
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Jonsson F, Byström B, Davidson AE, Backman LJ, Kellgren TG, Tuft SJ, Koskela T, Rydén P, Sandgren O, Danielson P, Hardcastle AJ, Golovleva I. Mutations in collagen, type XVII, alpha 1 (COL17A1) cause epithelial recurrent erosion dystrophy (ERED). Hum Mutat 2015; 36:463-73. [PMID: 25676728 DOI: 10.1002/humu.22764] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/02/2015] [Indexed: 01/04/2023]
Abstract
Corneal dystrophies are a clinically and genetically heterogeneous group of inherited disorders that bilaterally affect corneal transparency. They are defined according to the corneal layer affected and by their genetic cause. In this study, we identified a dominantly inherited epithelial recurrent erosion dystrophy (ERED)-like disease that is common in northern Sweden. Whole-exome sequencing resulted in the identification of a novel mutation, c.2816C>T, p.T939I, in the COL17A1 gene, which encodes collagen type XVII alpha 1. The variant segregated with disease in a genealogically expanded pedigree dating back 200 years. We also investigated a unique COL17A1 synonymous variant, c.3156C>T, identified in a previously reported unrelated dominant ERED-like family linked to a locus on chromosome 10q23-q24 encompassing COL17A1. We show that this variant introduces a cryptic donor site resulting in aberrant pre-mRNA splicing and is highly likely to be pathogenic. Bi-allelic COL17A1 mutations have previously been associated with a recessive skin disorder, junctional epidermolysis bullosa, with recurrent corneal erosions being reported in some cases. Our findings implicate presumed gain-of-function COL17A1 mutations causing dominantly inherited ERED and improve understanding of the underlying pathology.
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Affiliation(s)
- Frida Jonsson
- Department of Medical Biosciences/Medical and Clinical Genetics, Umeå University, Umeå, Sweden
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Liskova P, Dudakova L, Tesar V, Bednarova V, Kidorova J, Jirsova K, Davidson AE, Hardcastle AJ. Detailed assessment of renal function in a proband with Harboyan syndrome caused by a novel homozygous SLC4A11 nonsense mutation. Ophthalmic Res 2014; 53:30-5. [PMID: 25500497 DOI: 10.1159/000365109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Accepted: 05/28/2014] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS To identify the underlying molecular genetic cause of disease in a patient with Harboyan syndrome and to perform a detailed assessment of her renal function. We also assessed the influence of the SLC4A11 mutation identified on the corneal endothelium in the heterozygous state. METHODS A 55-year-old female was examined ophthalmologically, audiologically and nephrologically including 24-hour urine collection. The coding region of SLC4A11 was directly sequenced. Specular microscopy was performed in the proband's 21-year-old daughter. RESULTS The proband had bilateral iridectomy at the age of 3 months because of an initial diagnosis of congenital glaucoma and since the age of 12 years she underwent several keratoplasties in each eye. Nephrological examination did not reveal any abnormalities. Moderate bilateral sensorineural hearing loss was confirmed by audiometry. A novel homozygous mutation predicted to lead to a premature stop codon at the protein level, c.2188C>T; p.(Arg730*), was identified in SLC4A11. No changes in corneal endothelial cell morphology or density were observed in the heterozygous daughter. CONCLUSION In contrast to the Slc4a11(-/-) mouse, no abnormalities in daily renal ion excretion or polyuria were observed in the Harboyan syndrome patient. The mutation identified does not affect corneal endothelial cell morphology or density in the heterozygous state.
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Affiliation(s)
- Petra Liskova
- Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague, Czech Republic
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25
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Evans CJ, Liskova P, Dudakova L, Hrabcikova P, Horinek A, Jirsova K, Filipec M, Hardcastle AJ, Davidson AE, Tuft SJ. Identification of six novel mutations in ZEB1 and description of the associated phenotypes in patients with posterior polymorphous corneal dystrophy 3. Ann Hum Genet 2014; 79:1-9. [PMID: 25441224 DOI: 10.1111/ahg.12090] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 09/30/2014] [Indexed: 01/18/2023]
Abstract
Posterior polymorphous corneal dystrophy 3 (PPCD3) is a rare autosomal dominant disorder caused by mutations in ZEB1. To date all identified disease-causing variants were unique to the studied families, except for c.1576dup. We have detected six novel ZEB1 mutations; c.1749_1750del; p.(Pro584*) and c.1717_1718del; p.(Val573Phefs*12) in two Czech families, c.1176dup; p.(Ala393Serfs*19), c.1100C>A; p.(Ser367*), c.627del; p.(Phe209Leufs*11) in three British families and a splice site mutation, c.685-2A>G, in a patient of Sri Lankan origin. An additional British proband had the c.1576dup; p.(Val526Glyfs*3) mutation previously reported in other populations. Clinical findings were variable and included bilateral congenital corneal opacity in one proband, development of opacity before the age of 2 years in another individual and bilateral iris flocculi in yet another subject. The majority of eyes examined by corneal topography (10 out of 16) had an abnormally steep cornea (flat keratometry 46.5-52.7 diopters, steep keratometry 48.1-54.0 diopters). One proband underwent surgery for cryptorchidism. Our study further demonstrates that PPCD3 can present as corneal edema in early childhood, and that an abnormally steep keratometry is a common feature of this condition. As cryptorchidism has been previously observed in two other PPCD3 cases, its association with the disease warrants further investigation.
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Borman AD, Pearce LR, Mackay DS, Nagel-Wolfrum K, Davidson AE, Henderson R, Garg S, Waseem NH, Webster AR, Plagnol V, Wolfrum U, Farooqi IS, Moore AT. A homozygous mutation in the TUB gene associated with retinal dystrophy and obesity. Hum Mutat 2013; 35:289-93. [PMID: 24375934 PMCID: PMC4284018 DOI: 10.1002/humu.22482] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 11/04/2013] [Indexed: 01/30/2023]
Abstract
Inherited retinal dystrophies are a major cause of childhood blindness. Here, we describe the identification of a homozygous frameshift mutation (c.1194_1195delAG, p.Arg398Serfs*9) in TUB in a child from a consanguineous UK Caucasian family investigated using autozygosity mapping and whole-exome sequencing. The proband presented with obesity, night blindness, decreased visual acuity, and electrophysiological features of a rod cone dystrophy. The mutation was also found in two of the proband's siblings with retinal dystrophy and resulted in mislocalization of the truncated protein. In contrast to known forms of retinal dystrophy, including those caused by mutations in the tubby-like protein TULP-1, loss of function of TUB in the proband and two affected family members was associated with early-onset obesity, consistent with an additional role for TUB in energy homeostasis.
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Affiliation(s)
- Arundhati Dev Borman
- Moorfield's Eye Hospital, London, EC1C 2PD, UK; Institute of Ophthalmology, London, EC1V 9EL, UK
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27
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Sundaram V, Wilde C, Aboshiha J, Cowing J, Han C, Langlo CS, Chana R, Davidson AE, Sergouniotis PI, Bainbridge JW, Ali RR, Dubra A, Rubin G, Webster AR, Moore AT, Nardini M, Carroll J, Michaelides M. Retinal structure and function in achromatopsia: implications for gene therapy. Ophthalmology 2013; 121:234-245. [PMID: 24148654 DOI: 10.1016/j.ophtha.2013.08.017] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2013] [Revised: 08/09/2013] [Accepted: 08/13/2013] [Indexed: 11/15/2022] Open
Abstract
PURPOSE To characterize retinal structure and function in achromatopsia (ACHM) in preparation for clinical trials of gene therapy. DESIGN Cross-sectional study. PARTICIPANTS Forty subjects with ACHM. METHODS All subjects underwent spectral domain optical coherence tomography (SD-OCT), microperimetry, and molecular genetic testing. Foveal structure on SD-OCT was graded into 5 distinct categories: (1) continuous inner segment ellipsoid (ISe), (2) ISe disruption, (3) ISe absence, (4) presence of a hyporeflective zone (HRZ), and (5) outer retinal atrophy including retinal pigment epithelial loss. Foveal and outer nuclear layer (ONL) thickness was measured and presence of hypoplasia determined. MAIN OUTCOME MEASURES Photoreceptor appearance on SD-OCT imaging, foveal and ONL thickness, presence of foveal hypoplasia, retinal sensitivity and fixation stability, and association of these parameters with age and genotype. RESULTS Forty subjects with a mean age of 24.9 years (range, 6-52 years) were included. Disease-causing variants were found in CNGA3 (n = 18), CNGB3 (n = 15), GNAT2 (n = 4), and PDE6C (n = 1). No variants were found in 2 individuals. In all, 22.5% of subjects had a continuous ISe layer at the fovea, 27.5% had ISe disruption, 20% had an absent ISe layer, 22.5% had an HRZ, and 7.5% had outer retinal atrophy. No significant differences in age (P = 0.77), mean retinal sensitivity (P = 0.21), or fixation stability (P = 0.34) across the 5 SD-OCT categories were evident. No correlation was found between age and foveal thickness (P = 0.84) or between age and foveal ONL thickness (P = 0.12). CONCLUSIONS The lack of a clear association of disruption of retinal structure or function in ACHM with age suggests that the window of opportunity for intervention by gene therapy is wider in some individuals than previously indicated. Therefore, the potential benefit for a given subject is likely to be better predicted by specific measurement of photoreceptor structure rather than simply by age. The ability to directly assess cone photoreceptor preservation with SD-OCT and/or adaptive optics imaging is likely to prove invaluable in selecting subjects for future trials and measuring the trials' impact.
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Affiliation(s)
- Venki Sundaram
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK
| | - Caroline Wilde
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Jonathan Aboshiha
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK
| | - Jill Cowing
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Colin Han
- Summer Program for Undergraduate Research, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Christopher S Langlo
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Ravinder Chana
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK
| | - Alice E Davidson
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK
| | | | - James W Bainbridge
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK
| | - Robin R Ali
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Alfredo Dubra
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Gary Rubin
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK
| | - Marko Nardini
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Joseph Carroll
- Department of Cell Biology, Neurobiology & Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Biophysics, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK; Moorfields Eye Hospital, London, UK.
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Mackay DS, Borman AD, Sui R, van den Born LI, Berson EL, Ocaka LA, Davidson AE, Heckenlively JR, Branham K, Ren H, Lopez I, Maria M, Azam M, Henkes A, Blokland E, Qamar R, Webster AR, Cremers FPM, Moore AT, Koenekoop RK, Andreasson S, de Baere E, Bennett J, Chader GJ, Berger W, Golovleva I, Greenberg J, den Hollander AI, Klaver CCW, Klevering BJ, Lorenz B, Preising MN, Ramsear R, Roberts L, Roepman R, Rohrschneider K, Wissinger B. Screening of a large cohort of leber congenital amaurosis and retinitis pigmentosa patients identifies novel LCA5 mutations and new genotype-phenotype correlations. Hum Mutat 2013; 34:1537-1546. [PMID: 23946133 DOI: 10.1002/humu.22398] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Accepted: 08/05/2013] [Indexed: 11/11/2022]
Abstract
This study was undertaken to investigate the prevalence of sequence variants in LCA5 in patients with Leber congenital amaurosis (LCA), early-onset retinal dystrophy (EORD), and autosomal recessive retinitis pigmentosa (arRP); to delineate the ocular phenotypes; and to provide an overview of all published LCA5 variants in an online database. Patients underwent standard ophthalmic evaluations after providing informed consent. In selected patients, optical coherence tomography (OCT) and fundus autofluorescence imaging were possible. DNA samples from 797 unrelated patients with LCA and 211 with the various types of retinitis pigmentosa (RP) were screened by Sanger sequence analysis of all LCA5 exons and intron/exon junctions. Some LCA patients were prescreened by APEX technology or selected based on homozygosity mapping. In silico analyses were performed to assess the pathogenicity of the variants. Segregation analysis was performed where possible. Published and novel LCA5 variants were collected, amended for their correct nomenclature, and listed in a Leiden Open Variation Database (LOVD). Sequence analysis identified 18 new probands with 19 different LCA5 variants. Seventeen of the 19 LCA5 variants were novel. Except for two missense variants and one splice site variant, all variants were protein-truncating mutations. Most patients expressed a severe phenotype, typical of LCA. However, some LCA subjects had better vision and intact inner segment/outer segment (IS/OS) junctions on OCT imaging. In two families with LCA5 variants, the phenotype was more compatible with EORD with affected individuals displaying preserved islands of retinal pigment epithelium. One of the families with a milder phenotype harbored a homozygous splice site mutation; a second family was found to have a combination of a stop mutation and a missense mutation. This is the largest LCA5 study to date. We sequenced 1,008 patients (797 with LCA, 211 with arRP) and identified 18 probands with LCA5 mutations. Mutations in LCA5 are a rare cause of childhood retinal dystrophy accounting for ∼2% of disease in this cohort, and the majority of LCA5 mutations are likely null. The LCA5 protein truncating mutations are predominantly associated with LCA. However, in two families with the milder EORD, the LCA5 gene analysis revealed a homozygous splice site mutation in one and a stop mutation in combination with a missense mutation in a second family, suggesting that this milder phenotype is due to residual function of lebercilin and expanding the currently known phenotypic spectrum to include the milder early onset RP. Some patients have remaining foveal cone structures (intact IS/OS junctions on OCT imaging) and remaining visual acuities, which may bode well for upcoming treatment trials.
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Affiliation(s)
- Donna S Mackay
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Arundhati Dev Borman
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK.,Moorfields Eye Hospital, London, UK
| | - Ruifang Sui
- Ophthalmology, Peking Union Med College Hosp, Beijing, China
| | | | - Eliot L Berson
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear, Boston, Massachusetts, USA
| | - Louise A Ocaka
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Alice E Davidson
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - John R Heckenlively
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan
| | - Kari Branham
- Kellogg Eye Center, Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan
| | - Huanan Ren
- McGill Ocular Genetics Laboratory, Departments of Pediatric Surgery, Human Genetics and Ophthalmology, McGill University Health Centre, Montreal, Quebec, Canada
| | - Irma Lopez
- McGill Ocular Genetics Laboratory, Departments of Pediatric Surgery, Human Genetics and Ophthalmology, McGill University Health Centre, Montreal, Quebec, Canada
| | - Maleeha Maria
- Department of Human Genetics, Radboud University Medical Centre, and Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Maleeha Azam
- Department of Human Genetics, Radboud University Medical Centre, and Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands.,Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan
| | - Arjen Henkes
- Department of Human Genetics, Radboud University Medical Centre, and Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Ellen Blokland
- Department of Human Genetics, Radboud University Medical Centre, and Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Raheel Qamar
- Department of Biosciences, COMSATS Institute of Information Technology, Islamabad, Pakistan.,Al-Nafees Medical College & Hospital, Isra University, Islamabad, Pakistan
| | - Andrew R Webster
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK.,Moorfields Eye Hospital, London, UK
| | - Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Centre, and Nijmegen Centre for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Anthony T Moore
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK.,Moorfields Eye Hospital, London, UK
| | - Robert K Koenekoop
- McGill Ocular Genetics Laboratory, Departments of Pediatric Surgery, Human Genetics and Ophthalmology, McGill University Health Centre, Montreal, Quebec, Canada
| | | | - Sten Andreasson
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Elfride de Baere
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Jean Bennett
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Gerald J Chader
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Wolfgang Berger
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Irina Golovleva
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Jacquie Greenberg
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | | | | | - B Jeroen Klevering
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Birgit Lorenz
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Markus N Preising
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Raj Ramsear
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Lisa Roberts
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | - Ronald Roepman
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
| | | | - Bernd Wissinger
- Department of Human Genetics, Institute of Ophthalmology, UCL, London, UK
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Fujinami K, Sergouniotis PI, Davidson AE, Wright G, Chana RK, Tsunoda K, Tsubota K, Egan CA, Robson AG, Moore AT, Holder GE, Michaelides M, Webster AR. Clinical and molecular analysis of Stargardt disease with preserved foveal structure and function. Am J Ophthalmol 2013; 156:487-501.e1. [PMID: 23953153 DOI: 10.1016/j.ajo.2013.05.003] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2013] [Revised: 05/06/2013] [Accepted: 05/06/2013] [Indexed: 12/25/2022]
Abstract
PURPOSE To describe a cohort of patients with Stargardt disease who show a foveal-sparing phenotype. DESIGN Retrospective case series. METHODS The foveal-sparing phenotype was defined as foveal preservation on autofluorescence imaging, despite a retinopathy otherwise consistent with Stargardt disease. Forty such individuals were ascertained and a full ophthalmic examination was undertaken. Following mutation screening of ABCA4, the molecular findings were compared with those of patients with Stargardt disease but no foveal sparing. RESULTS The median age of onset and age at examination of 40 patients with the foveal-sparing phenotype were 43.5 and 46.5 years. The median logMAR visual acuity was 0.18. Twenty-two patients (22/40, 55%) had patchy parafoveal atrophy and flecks; 8 (20%) had numerous flecks at the posterior pole without atrophy; 7 (17.5%) had mottled retinal pigment epithelial changes; 2 (5%) had multiple atrophic lesions, extending beyond the arcades; and 1 (2.5%) had a bull's-eye appearance. The median central foveal thickness assessed with spectral-domain optical coherence tomographic images was 183.0 μm (n = 33), with outer retinal tubulation observed in 15 (45%). Twenty-two of 33 subjects (67%) had electrophysiological evidence of macular dysfunction without generalized retinal dysfunction. Disease-causing variants were found in 31 patients (31/40, 78%). There was a higher prevalence of the variant p.Arg2030Gln in the cohort with foveal sparing compared to the group with foveal atrophy (6.45% vs 1.07%). CONCLUSIONS The distinct clinical and molecular characteristics of patients with the foveal-sparing phenotype are described. The presence of 2 distinct phenotypes of Stargardt disease (foveal sparing and foveal atrophy) suggests that there may be more than 1 disease mechanism in ABCA4 retinopathy.
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Affiliation(s)
- Kaoru Fujinami
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom; Laboratory of Visual Physiology, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan; Department of Ophthalmology, Keio University, School of Medicine, Tokyo, Japan
| | - Panagiotis I Sergouniotis
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Alice E Davidson
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Genevieve Wright
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Ravinder K Chana
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Kazushige Tsunoda
- Laboratory of Visual Physiology, National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University, School of Medicine, Tokyo, Japan
| | - Catherine A Egan
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Anthony G Robson
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Anthony T Moore
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Graham E Holder
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Michel Michaelides
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom
| | - Andrew R Webster
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom.
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30
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Davidson AE, Schwarz N, Zelinger L, Stern-Schneider G, Shoemark A, Spitzbarth B, Gross M, Laxer U, Sosna J, Sergouniotis PI, Waseem NH, Wilson R, Kahn RA, Plagnol V, Wolfrum U, Banin E, Hardcastle AJ, Cheetham ME, Sharon D, Webster AR. Mutations in ARL2BP, encoding ADP-ribosylation-factor-like 2 binding protein, cause autosomal-recessive retinitis pigmentosa. Am J Hum Genet 2013; 93:321-9. [PMID: 23849777 DOI: 10.1016/j.ajhg.2013.06.003] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Revised: 05/03/2013] [Accepted: 06/04/2013] [Indexed: 01/01/2023] Open
Abstract
Retinitis pigmentosa (RP) is a genetically heterogeneous retinal degeneration characterized by photoreceptor death, which results in visual failure. Here, we used a combination of homozygosity mapping and exome sequencing to identify mutations in ARL2BP, which encodes an effector protein of the small GTPases ARL2 and ARL3, as causative for autosomal-recessive RP (RP66). In a family affected by RP and situs inversus, a homozygous, splice-acceptor mutation, c.101-1G>C, which alters pre-mRNA splicing of ARLBP2 in blood RNA, was identified. In another family, a homozygous c.134T>G (p.Met45Arg) mutation was identified. In the mouse retina, ARL2BP localized to the basal body and cilium-associated centriole of photoreceptors and the periciliary extension of the inner segment. Depletion of ARL2BP caused cilia shortening. Moreover, depletion of ARL2, but not ARL3, caused displacement of ARL2BP from the basal body, suggesting that ARL2 is vital for recruiting or anchoring ARL2BP at the base of the cilium. This hypothesis is supported by the finding that the p.Met45Arg amino acid substitution reduced binding to ARL2 and caused the loss of ARL2BP localization at the basal body in ciliated nasal epithelial cells. These data demonstrate a role for ARL2BP and ARL2 in primary cilia function and that this role is essential for normal photoreceptor maintenance and function.
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31
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Fujinami K, Sergouniotis PI, Davidson AE, Mackay DS, Tsunoda K, Tsubota K, Robson AG, Holder GE, Moore AT, Michaelides M, Webster AR. The clinical effect of homozygous ABCA4 alleles in 18 patients. Ophthalmology 2013; 120:2324-31. [PMID: 23769331 DOI: 10.1016/j.ophtha.2013.04.016] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 04/17/2013] [Accepted: 04/17/2013] [Indexed: 10/26/2022] Open
Abstract
PURPOSE To describe the phenotypic presentation of a cohort of individuals with homozygous disease-associated ABCA4 variants. DESIGN Retrospective case series. PARTICIPANTS Eighteen affected individuals from 13 families ascertained from a total cohort of 214 families with ABCA4-related retinal disease presenting to a single center. METHODS A detailed history was obtained, and color fundus photography, autofluorescence (AF) imaging, optical coherence tomography (OCT), and electrophysiologic assessment were performed. Phenotypes based on ophthalmoscopy, AF, and electrophysiology were assigned using previously reported characteristics. ABCA4 mutation detection was performed using the ABCR400 microarray (Asper Biotech, Tartu, Estonia) and high-throughput DNA sequencing, with direct sequencing used to assess segregation. MAIN OUTCOME MEASURES Detailed clinical, electrophysiologic, and molecular genetic findings. RESULTS Eleven disease-associated homozygous ABCA4 alleles were identified, including 1 frame shift, 2 stops, 1 intronic variant causing splice-site alteration, 2 complex missense variants, and 5 missense variants: p.Glu905fsX916, p.Arg1300X, p.Gln2220X, c.4253+4 C>T, p.Leu541Pro and p.Ala1038Val (homozygosity for complex allele), p.Val931Met and p.Arg1705Gln (complex allele), p.Arg212Cys, p.Cys1488Arg, p.Arg1640Trp, p.Gly1961Glu, and p.Leu2027Phe. Eight of these 11 homozygous alleles have not been reported previously. Six of 7 patients with homozygous null alleles had early-onset (<10 years) disease, with all 7 having a severe phenotype. Two patients with homozygous missense variants (p.Leu541Pro and p.Ala1038Val [complex], and p.Arg1640Trp) presented with a severe phenotype. Three patients with homozygous p.Gly1961Glu had adult-onset disease and a mild phenotype. One patient with homozygous p.Leu2027Phe showed a spared fovea and preserved visual acuity. CONCLUSIONS The phenotypes represented in patients identified as homozygous for presumed disease-associated ABCA4 variants gives insight into the effect of individual alleles. Null alleles have severe functional effects, and certain missense variants are similar to nulls, suggesting complete abrogation of protein function. The common alleles identified, p.Gly1961Glu and p. Leu2027Phe, both have a mild structural and functional effect on the adult retina; the latter is associated with relatively retained photoreceptor architecture and function at the fovea.
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Affiliation(s)
- Kaoru Fujinami
- UCL Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, London, United Kingdom; National Institute of Sensory Organs, National Tokyo Medical Center, Tokyo, Japan; Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
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Fujinami K, Lois N, Davidson AE, Mackay DS, Hogg CR, Stone EM, Tsunoda K, Tsubota K, Bunce C, Robson AG, Moore AT, Webster AR, Holder GE, Michaelides M. A longitudinal study of stargardt disease: clinical and electrophysiologic assessment, progression, and genotype correlations. Am J Ophthalmol 2013; 155:1075-1088.e13. [PMID: 23499370 DOI: 10.1016/j.ajo.2013.01.018] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 01/14/2013] [Accepted: 01/16/2013] [Indexed: 01/01/2023]
Abstract
PURPOSE To investigate the clinical and electrophysiologic natural history of Stargardt disease and correlate with the genotype. DESIGN Cohort study of 59 patients. METHODS Clinical history, examination, and electrophysiologic assessment were undertaken in a longitudinal survey. Patients were classified into 3 groups based on electrophysiologic findings, as previously published: Group 1 had dysfunction confined to the macula; Group 2 had macular and generalized cone system dysfunction; and Group 3 had macular and both generalized cone and rod system dysfunction. At baseline, there were 27 patients in Group 1, 17 in Group 2, and 15 in Group 3. Amplitude reduction of >50% in the relevant electroretinogram (ERG) component or a peak time shift of >3 ms for the 30 Hz flicker ERG or bright flash a-wave was considered clinically significant ERG deterioration. Molecular screening of ABCA4 was undertaken. RESULTS The mean age at baseline was 31.7 years, with the mean follow-up interval being 10.5 years. A total of 22% of patients from Group 1 showed ERG group transition during follow-up, with 11% progressing to Group 2 and 11% to Group 3. Forty-seven percent of patients in Group 2 progressed to Group 3. There was clinically significant ERG deterioration in 54% of all subjects: 22% of Group 1, 65% of Group 2, and 100% of Group 3. At least 1 disease-causing ABCA4 variant was identified in 47 patients. CONCLUSIONS All patients with initial rod ERG involvement demonstrated clinically significant electrophysiologic deterioration; only 20% of patients with normal full-field ERGs at baseline showed clinically significant progression. Such data assist counseling by providing more accurate prognostic information and are also highly relevant in the design, patient selection, and monitoring of potential therapeutic interventions.
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Davidson AE, Sergouniotis PI, Mackay DS, Wright GA, Waseem NH, Michaelides M, Holder GE, Robson AG, Moore AT, Plagnol V, Webster AR. RP1L1 variants are associated with a spectrum of inherited retinal diseases including retinitis pigmentosa and occult macular dystrophy. Hum Mutat 2013; 34:506-14. [PMID: 23281133 DOI: 10.1002/humu.22264] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Accepted: 12/05/2012] [Indexed: 11/09/2022]
Abstract
In one consanguineous family with retinitis pigmentosa (RP), a condition characterized by progressive visual loss due to retinal degeneration, homozygosity mapping, and candidate gene sequencing suggested a novel locus. Exome sequencing identified a homozygous frameshifting mutation, c.601delG, p.Lys203Argfs*28, in RP1L1 encoding RP 1-like1, a photoreceptor-specific protein. A screen of a further 285 unrelated individuals with autosomal recessive RP identified an additional proband, homozygous for a missense variant, c.1637G>C, p.Ser546Thr, in RP1L1. A distinct retinal disorder, occult macular dystrophy (OCMD) solely affects the central retinal cone photoreceptors and has previously been reported to be associated with variants in the same gene. The association between mutations in RP1L1 and the disorder OCMD was explored by screening a cohort of 28 unrelated individuals with the condition; 10 were found to harbor rare (minor allele frequency ≤0.5% in the 1,000 genomes dataset) heterozygous RP1L1 missense variants. Analysis of family members revealed many unaffected relatives harboring the same variant. Linkage analysis excluded the possibility of a recessive mode of inheritance, and sequencing of RP1, a photoreceptor protein that interacts with RP1L1, excluded a digenic mechanism involving this gene. These findings imply an important and diverse role for RP1L1 in human retinal physiology and disease.
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Affiliation(s)
- Alice E Davidson
- University College London Institute of Ophthalmology, London, UK
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Webb TR, Parfitt DA, Gardner JC, Martinez A, Bevilacqua D, Davidson AE, Zito I, Thiselton DL, Ressa JHC, Apergi M, Schwarz N, Kanuga N, Michaelides M, Cheetham ME, Gorin MB, Hardcastle AJ. Deep intronic mutation in OFD1, identified by targeted genomic next-generation sequencing, causes a severe form of X-linked retinitis pigmentosa (RP23). Hum Mol Genet 2012; 21:3647-54. [PMID: 22619378 DOI: 10.1093/hmg/dds194] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
X-linked retinitis pigmentosa (XLRP) is genetically heterogeneous with two causative genes identified, RPGR and RP2. We previously mapped a locus for a severe form of XLRP, RP23, to a 10.71 Mb interval on Xp22.31-22.13 containing 62 genes. Candidate gene screening failed to identify a causative mutation, so we adopted targeted genomic next-generation sequencing of the disease interval to determine the molecular cause of RP23. No coding variants or variants within or near splice sites were identified. In contrast, a variant deep within intron 9 of OFD1 increased the splice site prediction score 4 bp upstream of the variant. Mutations in OFD1 cause the syndromic ciliopathies orofaciodigital syndrome-1, which is male lethal, Simpson-Golabi-Behmel syndrome type 2 and Joubert syndrome. We tested the effect of the IVS9+706A>G variant on OFD1 splicing in vivo. In RP23 patient-derived RNA, we detected an OFD1 transcript with the insertion of a cryptic exon spliced between exons 9 and 10 causing a frameshift, p.N313fs.X330. Correctly spliced OFD1 was also detected in patient-derived RNA, although at reduced levels (39%), hence the mutation is not male lethal. Our data suggest that photoreceptors are uniquely susceptible to reduced expression of OFD1 and that an alternative disease mechanism can cause XLRP. This disease mechanism of reduced expression for a syndromic ciliopathy gene causing isolated retinal degeneration is reminiscent of CEP290 intronic mutations that cause Leber congenital amaurosis, and we speculate that reduced dosage of correctly spliced ciliopathy genes may be a common disease mechanism in retinal degenerations.
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Affiliation(s)
- Tom R Webb
- UCL Institute of Ophthalmology, London EC1V 9EL, UK
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Poulter JA, Davidson AE, Ali M, Gilmour DF, Parry DA, Mintz-Hittner HA, Carr IM, Bottomley HM, Long VW, Downey LM, Sergouniotis PI, Wright GA, MacLaren RE, Moore AT, Webster AR, Inglehearn CF, Toomes C. Recessive mutations in TSPAN12 cause retinal dysplasia and severe familial exudative vitreoretinopathy (FEVR). Invest Ophthalmol Vis Sci 2012; 53:2873-9. [PMID: 22427576 DOI: 10.1167/iovs.11-8629] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Familial exudative vitreoretinopathy (FEVR) is an inherited disorder that disrupts the development of the retinal vasculature and can result in blindness. FEVR is genetically heterogeneous and mutations in four genes, NDP, FZD4, LRP5, and TSPAN12, encoding components of a novel ligand-receptor complex that activates the Norrin-β-catenin signaling pathway, account for approximately 50% of cases. We recently identified mutations in TSPAN12 as a cause of dominant FEVR. The purpose of this study was to identify recessive TSPAN12 mutations in FEVR patients. METHODS Mutation screening was performed by directly sequencing PCR products generated from genomic DNA with primers designed to amplify the coding sequence of TSPAN12. Splicing defects were verified by reverse transcriptase PCR of leukocyte cDNA. RESULTS TSPAN12 screening in a large dominant FEVR family unexpectedly led to the identification of homozygous mutations in severely affected family members, whereas mildly affected family members were heterozygous. Further screening in a cohort of 10 retinal dysplasia/severe FEVR patients identified an additional three cases with recessive TSPAN12 mutations. In all examined cases, single mutation carriers were mildly affected compared to patients harboring two TSPAN12 mutations. CONCLUSIONS We report for the first time recessive mutations in TSPAN12 and describe the first genetic cause for the clinical variation seen in FEVR families. Our data raise the possibility that patients with severe FEVR actually may harbor two mutant alleles, derived either from the same gene or potentially from other genes encoding components of the Norrin-β-catenin signaling pathway.
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Affiliation(s)
- James A Poulter
- Leeds Institute of Molecular Medicine, St. James's University Hospital, Leeds, United Kingdom
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Sergouniotis PI, Davidson AE, Lenassi E, Devery SR, Moore AT, Webster AR. Retinal Structure, Function, and Molecular Pathologic Features in Gyrate Atrophy. Ophthalmology 2012; 119:596-605. [DOI: 10.1016/j.ophtha.2011.09.017] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 09/07/2011] [Accepted: 09/08/2011] [Indexed: 10/14/2022] Open
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Ramsden SC, Davidson AE, Leroy BP, Moore AT, Webster AR, Black GCM, Manson FDC. Clinical utility gene card for: BEST1-related dystrophies (Bestrophinopathies). Eur J Hum Genet 2012; 20:ejhg2011251. [PMID: 22234150 DOI: 10.1038/ejhg.2011.251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Simon C Ramsden
- Genetic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
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Borman AD, Davidson AE, O'Sullivan J, Thompson DA, Robson AG, De Baere E, Black GCM, Webster AR, Holder GE, Leroy BP, Manson FDC, Moore AT. Childhood-onset autosomal recessive bestrophinopathy. ACTA ACUST UNITED AC 2011; 129:1088-93. [PMID: 21825197 DOI: 10.1001/archophthalmol.2011.197] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Arundhati Dev Borman
- Molecular Genetics, Institute of Ophthalmology, University College London, Moorfields Eye Hospital, England.
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Low S, Davidson AE, Holder GE, Hogg CR, Bhattacharya SS, Black GC, Foster PJ, Webster AR. Autosomal dominant Best disease with an unusual electrooculographic light rise and risk of angle-closure glaucoma: a clinical and molecular genetic study. Mol Vis 2011; 17:2272-82. [PMID: 21921978 PMCID: PMC3171497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 08/18/2011] [Indexed: 11/16/2022] Open
Abstract
PURPOSE To describe the clinical and molecular characteristics of two families with autosomal dominant Best disease and atypical electrooculography (EOG). METHODS Four affected individuals from two families were ascertained. Detailed ophthalmic examinations, refraction, and biometry (anterior chamber depth [ACD] and axial length [AL]), gonioscopy, optical coherence tomography of the anterior segment and retina, retinal imaging, and electrophysiological assessment were performed. Arden ratios from EOG testing were calculated by direct measurement of the light peak to dark trough amplitudes. Mutations in bestrophin 1 (BEST1) were identified by bidirectional Sanger sequencing. In family 1, segregation of BEST1 alleles was performed by assaying four microsatellite markers (D11S935, D11S4102, D11S987, and D11S4162) that flank BEST1. RESULTS The proband from family 1 (three of four siblings affected with Best disease) was 42 years old with bilateral macular vitelliform lesions, advanced angle closure glaucoma (ACG), a normal electroretinogram, and no EOG light rise. Her 44-year-old brother had similar fundus appearances and an EOG light rise of 170%. Their 48-year-old sister had a normal left fundus, whereas the right fundus showed a vitelliform lesion and subretinal thickening. There was no EOG light rise detectable from either eye. Mutation analysis of BEST1 showed all affected siblings to be heterozygous for a missense mutation, c.914T>C, p.Phe305Ser. Their unaffected sister had an EOG light rise of 200%, a normal fundus appearance, and did not harbor the BEST1 mutation. Haplotype analysis of family 1 showed that the affected brother with the 170% EOG light rise had inherited the same nondiseased parental BEST1 allele as his unaffected sister. The other two affected sisters with undetectable EOG light rises shared a different nondiseased parental BEST1 allele. An unrelated 53-year-old female carrying the same c.914T>C, p.Phe305Ser mutation showed typical features of Best disease and an EOG light rise of 180%. All four siblings from family 1 had shorter axial biometry (ACD range 2.06-2.74 mm; AL range 20.46-22.60 mm) than the normal population, contributing to their risk of ACG development. Proband 2 had deeper ACDs (2.83 mm OD and 2.85 mm OS), but similar ALs (21.52 mm OD and 21.42 mm OS) compared to family 1. She had no gonioscopic evidence of angle closure. CONCLUSIONS A near normal EOG light rise is uncommon in molecularly confirmed Best disease, and in the present report is associated with the same mutation in two families, suggesting a specific role for this amino acid in the retinal pigment epithelium dysfunction associated with this disorder. Haplotype analysis in family 1 was consistent with an effect of the nondisease allele in mediating the presence of an EOG light rise. Clinical assessment of ACG risk is recommended for BEST1 mutation carriers and their first degree relatives.
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Affiliation(s)
- Sancy Low
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
| | - Alice E. Davidson
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK,Genetic Medicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Graham E. Holder
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
| | - Chris R. Hogg
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
| | - Shomi S. Bhattacharya
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
| | - Graeme C. Black
- Genetic Medicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Paul J. Foster
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
| | - Andrew R. Webster
- NIHR Biomedical Research Centre for Ophthalmology, Moorfields Eye Hospital and UCL Institute of Ophthalmology, London, UK
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Sergouniotis PI, Davidson AE, Mackay DS, Li Z, Yang X, Plagnol V, Moore AT, Webster AR. Recessive mutations in KCNJ13, encoding an inwardly rectifying potassium channel subunit, cause leber congenital amaurosis. Am J Hum Genet 2011; 89:183-90. [PMID: 21763485 DOI: 10.1016/j.ajhg.2011.06.002] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2011] [Revised: 06/03/2011] [Accepted: 06/07/2011] [Indexed: 12/13/2022] Open
Abstract
Inherited retinal degenerations, including retinitis pigmentosa (RP) and Leber congenital amaurosis (LCA), comprise a group of disorders showing high genetic and allelic heterogeneity. The determination of a full catalog of genes that can, when mutated, cause human retinal disease is a powerful means to understand the molecular physiology and pathology of the human retina. As more genes are found, remaining ones are likely to be rarer and/or unexpected candidates. Here, we identify a family in which all known RP/LCA-related genes are unlikely to be associated with their disorder. A combination of homozygosity mapping and exome sequencing identifies a homozygous nonsense mutation, c.496C>T (p.Arg166X), in a gene, KCNJ13, encoding a potassium channel subunit Kir7.1. A screen of a further 333 unrelated individuals with recessive retinal degeneration identified an additional proband, homozygous for a missense mutation, c.722T>C (p.Leu241Pro), in the same gene. The three affected members of the two families have been diagnosed with LCA. All have a distinct and unusual retinal appearance and a similar early onset of visual loss, suggesting both impaired retinal development and progressive retinal degeneration, involving both rod and cone pathways. Examination of heterozygotes revealed no ocular disease. This finding implicates Kir7.1 as having an important role in human retinal development and maintenance. This disorder adds to a small diverse group of diseases consequent upon loss or reduced function of inwardly rectifying potassium channels affecting various organs. The distinct retinal phenotype that results from biallelic mutations in KCNJ13 should facilitate the molecular diagnosis in further families.
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Davidson AE, Millar ID, Burgess-Mullan R, Maher GJ, Urquhart JE, Brown PD, Black GCM, Manson FDC. Functional characterization of bestrophin-1 missense mutations associated with autosomal recessive bestrophinopathy. Invest Ophthalmol Vis Sci 2011; 52:3730-6. [PMID: 21330666 DOI: 10.1167/iovs.10-6707] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Autosomal recessive bestrophinopathy (ARB) is a retinal dystrophy affecting macular and retinal pigmented epithelium function resulting from homozygous or compound heterozygous mutations in BEST1. In this study we characterize the functional implications of missense bestrophin-1 mutations that cause ARB by investigating their effect on bestrophin-1's chloride conductance, cellular localization, and stability. METHODS The chloride conductance of wild-type bestropin-1 and a series of ARB mutants were determined by whole-cell patch-clamping of transiently transfected HEK cells. The effect of ARB mutations on the cellular localization of bestrophin-1 was determined by confocal immunofluorescence on transiently transfected MDCK II cells that had been polarized on Transwell filters. Protein stability of wild-type and ARB mutant forms of bestrophin-l was determined by the addition of proteasomal or lysosomal inhibitors to transiently transfected MDCK II cells. Lysates were then analyzed by Western blot analysis. RESULTS All ARB mutants investigated produced significantly smaller chloride currents compared to wild-type bestrophin-1. Additionally, co-transfection of compound heterozygous mutants abolished chloride conductance in contrast to co-transfections of a single mutant with wild-type bestrophin-l, reflecting the recessive nature of the condition. In control experiments, expression of two dominant vitelliform macular dystrophy mutants was shown to inhibit wild-type currents. Cellular localization of ARB mutants demonstrated that the majority did not traffic correctly to the plasma membrane and that five of these seven mutants were rapidly degraded by the proteasome. Two ARB-associated mutants (p.D312N and p.V317M) that were not trafficked correctly nor targeted to the proteasome had a distinctive appearance, possibly indicative of aggresome or aggresome-like inclusion bodies. CONCLUSIONS Differences in cellular processing mechanisms for different ARB associated mutants lead to the same disease phenotype. The existence of distinct pathogenic disease mechanisms has important ramifications for potential gene replacement therapies since we show that missense mutations associated with an autosomal recessive disease have a pathogenic influence beyond simple loss of function.
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Affiliation(s)
- Alice E Davidson
- School of Biomedicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals, NHS Foundation Trust, Manchester, United Kingdom
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Davidson AE, Sergouniotis PI, Burgess-Mullan R, Hart-Holden N, Low S, Foster PJ, Manson FD, Black GC, Webster AR. A synonymous codon variant in two patients with autosomal recessive bestrophinopathy alters in vitro splicing of BEST1. Mol Vis 2010; 16:2916-22. [PMID: 21203346 PMCID: PMC3013070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Accepted: 12/25/2010] [Indexed: 11/05/2022] Open
Abstract
PURPOSE Autosomal recessive bestrophinopathy (ARB) is a newly defined retinal dystrophy caused by biallelic mutations in bestrophin-1 (BEST1) and is hypothesized to represent the null bestrophin-1 phenotype in humans. The aim was to determine whether a synonymous BEST1 variant, c.102C>T, identified in two unrelated ARB patients, alters pre-mRNA splicing of the gene. Additionally a detailed phenotypic characterization of this distinctive condition is presented for both patients. METHODS BEST1 was analyzed by direct sequencing. Patients underwent standard ophthalmic assessment. In silico and in vitro analysis using a minigene system was performed to assess whether a synonymous variant identified, c.102C>T p.Gly34Gly, alters pre-mRNA splicing of BEST1. RESULTS Both ARB patients harbored either proven (patient 1; c.102C>T p.Gly34Gly and c.572T>C p.Leu191Pro) or presumed (patient 2; c.102C>T p.Gly34Gly and c.1470_1471delCA, p.His490GlnfsX24) biallelic mutations in BEST1 and were found to have phenotypes consistent with ARB. In vitro analysis of the synonymous variant, c.102C>T p.Gly34Gly, demonstrated it to introduce a cryptic splice donor site 52 nucleotides upstream of the actual splice donor site. CONCLUSIONS The novel BEST1 variant identified, c.102C>T p.Gly34Gly, alters pre-mRNA splicing in vitro and is potentially pathogenic. In vivo this splicing variant is predicted to lead to the production of an mRNA transcript with a premature termination codon (p.Glu35TrpfsX11) that is predicted to be degraded by NMD.
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Affiliation(s)
- Alice E. Davidson
- School of Biomedicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK,Institute of Ophthalmology, University College London, London, UK
| | | | - Rosemary Burgess-Mullan
- School of Biomedicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Nichola Hart-Holden
- School of Biomedicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Sancy Low
- Moorfields Eye Hospital, London, UK,Institute of Ophthalmology, University College London, London, UK
| | - Paul J. Foster
- Moorfields Eye Hospital, London, UK,Institute of Ophthalmology, University College London, London, UK
| | - Forbes D.C. Manson
- School of Biomedicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Graeme C.M. Black
- School of Biomedicine, The University of Manchester, Manchester Academic Health Science Centre, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
| | - Andrew R. Webster
- Moorfields Eye Hospital, London, UK,Institute of Ophthalmology, University College London, London, UK
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Davidson AE, Millar ID, Urquhart JE, Burgess-Mullan R, Shweikh Y, Parry N, O'Sullivan J, Maher GJ, McKibbin M, Downes SM, Lotery AJ, Jacobson SG, Brown PD, Black GC, Manson FD. Missense mutations in a retinal pigment epithelium protein, bestrophin-1, cause retinitis pigmentosa. Am J Hum Genet 2009; 85:581-92. [PMID: 19853238 DOI: 10.1016/j.ajhg.2009.09.015] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2009] [Revised: 09/16/2009] [Accepted: 09/24/2009] [Indexed: 10/20/2022] Open
Abstract
Bestrophin-1 is preferentially expressed at the basolateral membrane of the retinal pigmented epithelium (RPE) of the retina. Mutations in the BEST1 gene cause the retinal dystrophies vitelliform macular dystrophy, autosomal-dominant vitreochoroidopathy, and autosomal-recessive bestrophinopathy. Here, we describe four missense mutations in bestrophin-1, three that we believe are previously unreported, in patients diagnosed with autosomal-dominant and -recessive forms of retinitis pigmentosa (RP). The physiological function of bestrophin-1 remains poorly understood although its heterologous expression induces a Cl--specific current. We tested the effect of RP-causing variants on Cl- channel activity and cellular localization of bestrophin-1. Two (p.L140V and p.I205T) produced significantly decreased chloride-selective whole-cell currents in comparison to those of wild-type protein. In a model system of a polarized epithelium, two of three mutations (p.L140V and p.D228N) caused mislocalization of bestrophin-1 from the basolateral membrane to the cytoplasm. Mutations in bestrophin-1 are increasingly recognized as an important cause of inherited retinal dystrophy.
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Burgess R, MacLaren RE, Davidson AE, Urquhart JE, Holder GE, Robson AG, Moore AT, Keefe RO, Black GCM, Manson FDC. ADVIRC is caused by distinct mutations in BEST1 that alter pre-mRNA splicing. J Med Genet 2008; 46:620-5. [DOI: 10.1136/jmg.2008.059881] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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45
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Abstract
The zebrafish embryo is especially valuable for cell biological studies because of its optical clarity. In this system, use of an in vivo fluorescent reporter has been limited to green fluorescent protein (GFP). We have examined other fluorescent proteins alone or in conjunction with GFP to investigate their efficacy as markers for multi-labeling purposes in live zebrafish. By injecting plasmid DNA containing fluorescent protein expression cassettes, we generated single-, double-, or triple-labeled embryos using GFP, blue fluorescent protein (BFP, a color-shifted GFP), and red fluorescent protein (DsRed, a wild-type protein structurally related to GFP). Fluorescent imaging demonstrates that GFP and DsRed are highly stable proteins, exhibiting no detectable photoinstability, and a high signal-to-noise ratio. BFP demonstrated detectable photoinstability and a lower signal-to-noise ratio than either GFP or DsRed. Using appropriate filter sets, these fluorescent proteins can be independently detected even when simultaneously expressed in the same cells. Multiple labels in individual zebrafish cells open the door to a number of biological avenues of investigation, including multiple, independent tags of transgenic fish lines, lineage studies of wild-type proteins expressed using polycistronic messages, and the detection of protein-protein interactions at the subcellular level using fluorescent protein fusions.
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Affiliation(s)
- K R Finley
- University of Minnesota, Minneapolis, MN, USA
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46
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Davidson AE, Klein DE, Settipane GA, Alario AJ. Access to care among children visiting the emergency room with acute exacerbations of asthma. Ann Allergy 1994; 72:469-473. [PMID: 8179236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To determine differences in access to continuing and preventive care among pediatric patients utilizing the emergency room for treatment of acute exacerbation of asthma, families of 170 asthma patients aged 2 to 17 years were surveyed prospectively. An interview schedule instrument generated information about socioeconomic factors, source of medical care including maintenance and specialty care, medication use, and plans for management of asthma exacerbations. A primary physician or clinic could be identified by 162 patients (95%). Regular preventive therapy (cromolyn, theophylline, or steroids) was used by 45 patients (27%). Allergy evaluations had been previously performed for 59 patients (35%). "Come to Emergency Room" was part of the asthma management plan for 56 patients (33%) and was the only asthma management plan for 34 patients (20%). Logistic regression analysis found that black and Hispanic patients (odds ratio = 0.38) and patients with Medicaid (odds ratio = 0.43) were less likely to call their MD or clinic prior to reporting to the emergency room. Patients with Medicaid were more likely to have two or more prior emergency room visits compared with a group of patients with private insurance and self-paying patients (odds ratio = 4.17). While the majority of patients in this study could identify a source of primary care, patients on Medicaid were significantly less likely to access continuing and preventive care and more likely to utilize the emergency room.
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Affiliation(s)
- A E Davidson
- Department of Allergy and Clinical Immunology, Rhode Island Hospital, Providence
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47
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Weltman JK, Melucci CL, Chen J, Davidson AE. Internalization of monoclonal antibodies selected for immunotoxin activity against small-cell lung cancer. Hybridoma (Larchmt) 1992; 11:547-59. [PMID: 1334041 DOI: 10.1089/hyb.1992.11.547] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Two hybridomas producing MOABs with anti-SCLC activity were selected for immunotoxin activity by an indirect screen and were twice cloned. Binding activity of the MOABs to SCLC cells was demonstrated by immunoperoxidase activity, which could be blocked by streptavidin. The MOABs mediated the internalization of a biotinylated Fab' anti-mouse Ig marker at 37 degrees C. Internalization of the biotinylated marker by the SCLC target cells resulted in protection of the marker from streptavidin-blocking. These results show that MOABs selected for immunotoxin activity against SCLC can mediate internalization of an antibody fragment with a mass about 50% greater than that of the toxin. MOABs selected for immunotoxin activity may be useful for delivering agents other than toxins to the inside of SCLC cells.
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Affiliation(s)
- J K Weltman
- Department of Medical Oncology, Rhode Island Hospital 02903
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48
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Abstract
Urticaria and angioedema are commonly seen in the outpatient setting. Their pathogenesis involves complex cellular and humoral factors. Diagnosis depends on historical information such as duration of symptoms, exacerbating factors, and atopy. While many etiologic factors have been implicated, in most chronic cases no specific etiology is found. This article reviews physical and hereditary syndromes and discusses therapeutic regimens based on the duration and severity of symptoms.
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Affiliation(s)
- A E Davidson
- Department of Pediatrics and Medicine, Rhode Island Hospital, Providence 02903
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49
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Davidson AE, Passero MA, Settipane GA. Buckwheat-induced anaphylaxis: a case report. Ann Allergy 1992; 69:158-9. [PMID: 1510289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Buckwheat (Fagopyrum schulentum) is not taxonomically related to wheat and other cereal grains. Buckwheat flour is used as a wheat substitute in breads, biscuits, pancakes, and crepes. Occupational exposure to buckwheat flour has been associated with rhinitis, conjunctivitis, contact urticaria, and occupational asthma. We present a patient who developed urticaria and hypotension after ingestion of buckwheat crepes. Skin testing by the prick technique revealed 3+ positive reaction to buckwheat with negative reactions to other foods including wheat, egg white, and milk. RAST for anti-buckwheat IgE was strongly positive. Buckwheat ingestion is a potential cause of food-related anaphylaxis. There does not appear to be cross-reactivity between buckwheat and wheat allergy.
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50
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Abstract
For persons hypersensitive to latex, continued exposure may result in a life-threatening situation. Since 1979 reports appeared supporting evidence of urticaria, rhinitis, asthma, and anaphylaxis in association with latex exposure. We present two cases of latex hypersensitivity, patients who reacted to latex on skin-prick and radioallergosorbent tests (RAST). A 30-year-old surgeon developed reactions to latex gloves. On skin-prick testing to latex extract in saline, he was 4+. RAST latex antigen-specific IgE was 50.75 times control. The second case is that of a 24-year-old nurse who underwent multiple corrective surgeries for congenital birth defects and experienced reactions to latex. On skin-prick testing to an extract of latex in saline, she was 2+. RAST latex antigen-specific IgE was 23.37 times control. Both patients were given epinephrine and diphenhydramine and advised to use latex-free gloves and to avoid latex products. As health care personnel contact with latex products increases because of new guidelines for the prevention of sexually transmitted diseases, more adverse reactions in this subpopulation will occur.
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Affiliation(s)
- D J Ber
- Division of Allergy/Immunology, Rhode Island Hospital, Providence
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