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Andhika NS, Biswas S, Hardcastle C, Green DJ, Ramsden SC, Birney E, Black GC, Sergouniotis PI. Using computational approaches to enhance the interpretation of missense variants in the PAX6 gene. Eur J Hum Genet 2024; 32:1005-1013. [PMID: 38849599 PMCID: PMC11292026 DOI: 10.1038/s41431-024-01638-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Revised: 04/12/2024] [Accepted: 05/14/2024] [Indexed: 06/09/2024] Open
Abstract
The PAX6 gene encodes a highly-conserved transcription factor involved in eye development. Heterozygous loss-of-function variants in PAX6 can cause a range of ophthalmic disorders including aniridia. A key molecular diagnostic challenge is that many PAX6 missense changes are presently classified as variants of uncertain significance. While computational tools can be used to assess the effect of genetic alterations, the accuracy of their predictions varies. Here, we evaluated and optimised the performance of computational prediction tools in relation to PAX6 missense variants. Through inspection of publicly available resources (including HGMD, ClinVar, LOVD and gnomAD), we identified 241 PAX6 missense variants that were used for model training and evaluation. The performance of ten commonly used computational tools was assessed and a threshold optimization approach was utilized to determine optimal cut-off values. Validation studies were subsequently undertaken using PAX6 variants from a local database. AlphaMissense, SIFT4G and REVEL emerged as the best-performing predictors; the optimized thresholds of these tools were 0.967, 0.025, and 0.772, respectively. Combining the prediction from these top-three tools resulted in lower performance compared to using AlphaMissense alone. Tailoring the use of computational tools by employing optimized thresholds specific to PAX6 can enhance algorithmic performance. Our findings have implications for PAX6 variant interpretation in clinical settings.
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Affiliation(s)
- Nadya S Andhika
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Susmito Biswas
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Claire Hardcastle
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - David J Green
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - Simon C Ramsden
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Ewan Birney
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge, UK
| | - Graeme C Black
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK
| | - Panagiotis I Sergouniotis
- Division of Evolution, Infection and Genomics, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK.
- Manchester Royal Eye Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- Manchester Centre for Genomic Medicine, Saint Mary's Hospital, Manchester University NHS Foundation Trust, Manchester, UK.
- European Molecular Biology Laboratory, European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge, UK.
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2
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Yahalom C, Anteby I, Hendler K, Harel T, Eilat A, Macarov M. Genetics of bilateral pediatric cataract in the Israeli and Palestinian populations. Graefes Arch Clin Exp Ophthalmol 2024:10.1007/s00417-024-06546-2. [PMID: 38874774 DOI: 10.1007/s00417-024-06546-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 06/03/2024] [Accepted: 06/06/2024] [Indexed: 06/15/2024] Open
Abstract
PURPOSE Bilateral pediatric cataract (BPC) is one of the most common causes of childhood visual impairment and blindness worldwide. A significant percentage of pediatric cataracts are caused by genetic alterations. We aim to characterize the set of genes and variants that cause BPC in the Israeli and Palestinian populations and to assess genotype-phenotype correlation. METHODS Retrospective study in a multidisciplinary center for visual impairment, located in a tertiary medical center. Medical charts of families who underwent genetic counseling because of BPC in a family member were reviewed. Clinical characteristics and genetic tests results were obtained from medical records of affected subjects. RESULTS Twenty-two families (47 patients) underwent genetic counseling and completed genetic testing. Causative variants were identified in 18/22 (81.8%) of the families, including 3 novel variants. Genetic testing used included mainly panel for congenital cataracts and whole exome sequencing. Eleven families performed genetic testing with the intention of future pregnancy planning. Main causative genes identified were crystalline genes followed by transcription factor genes. BCOR gene variants were associated with persistent fetal vasculature (PFV) cataract in two of three families. CONCLUSIONS Combined molecular techniques are useful in identifying variants causing pediatric cataracts and showed a high detection rate in our population. BCOR gene variants might be associated with PFV type of cataracts. The study of pathogenic variants may aid in family planning and prevention of pediatric cataracts in future pregnancies. Additionally, in certain cases, it assists in diagnosing non-suspected syndromic types of pediatric cataracts.
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Affiliation(s)
- Claudia Yahalom
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, 12000, POB, Israel.
| | - Irene Anteby
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, 12000, POB, Israel
| | - Karen Hendler
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, 12000, POB, Israel
| | - Tamar Harel
- Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Genetics and Metabolic Diseases, Hadassah Medical Center, Jerusalem, Israel
| | - Avital Eilat
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, 12000, POB, Israel
- Department of Genetics and Metabolic Diseases, Hadassah Medical Center, Jerusalem, Israel
| | - Michal Macarov
- Department of Ophthalmology, Hadassah Medical Center, Jerusalem, 12000, POB, Israel
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3
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Grainger RM, Lauderdale JD, Collins JL, Trout KL, McCullen Krantz S, Wolfe SS, Netland PA. Report on the 2021 Aniridia North America symposium on PAX6, aniridia, and beyond. Ocul Surf 2023; 29:423-431. [PMID: 37247841 DOI: 10.1016/j.jtos.2023.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 05/31/2023]
Abstract
The inaugural Aniridia North America (ANA) Symposium was held on the first weekend in November 2021 in Charlottesville, VA, at the University of Virginia. The purpose of this meeting was to bring together an international group of scientists, physicians, patient advocacy groups, and individuals with aniridia to discuss recent advances in knowledge about aniridia and other congenital eye diseases and the development of potential treatments for congenital eye disorders using personalized medicine. Leaders in several areas of eye research and clinical treatment provided a broad perspective on new research advances that impact an understanding of the causes of the damage to the eye associated with aniridia and the development of novel treatments for this and related disorders. Here we summarize the research discussed at the symposium.
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Affiliation(s)
- Robert M Grainger
- Aniridia North America, LaGrange, IL, 60525, USA; Department of Biology, 326 Gilmer Hall University of Virginia 485 McCormick Road P.O. Box 400328 Charlottesville, VA 22904, USA.
| | - James D Lauderdale
- Aniridia North America, LaGrange, IL, 60525, USA; Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.
| | | | | | | | | | - Peter A Netland
- Aniridia North America, LaGrange, IL, 60525, USA; Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
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4
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Cvekl A, Camerino MJ. Generation of Lens Progenitor Cells and Lentoid Bodies from Pluripotent Stem Cells: Novel Tools for Human Lens Development and Ocular Disease Etiology. Cells 2022; 11:3516. [PMID: 36359912 PMCID: PMC9658148 DOI: 10.3390/cells11213516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 10/31/2022] [Accepted: 11/02/2022] [Indexed: 11/09/2022] Open
Abstract
In vitro differentiation of human pluripotent stem cells (hPSCs) into specialized tissues and organs represents a powerful approach to gain insight into those cellular and molecular mechanisms regulating human development. Although normal embryonic eye development is a complex process, generation of ocular organoids and specific ocular tissues from pluripotent stem cells has provided invaluable insights into the formation of lineage-committed progenitor cell populations, signal transduction pathways, and self-organization principles. This review provides a comprehensive summary of recent advances in generation of adenohypophyseal, olfactory, and lens placodes, lens progenitor cells and three-dimensional (3D) primitive lenses, "lentoid bodies", and "micro-lenses". These cells are produced alone or "community-grown" with other ocular tissues. Lentoid bodies/micro-lenses generated from human patients carrying mutations in crystallin genes demonstrate proof-of-principle that these cells are suitable for mechanistic studies of cataractogenesis. Taken together, current and emerging advanced in vitro differentiation methods pave the road to understand molecular mechanisms of cataract formation caused by the entire spectrum of mutations in DNA-binding regulatory genes, such as PAX6, SOX2, FOXE3, MAF, PITX3, and HSF4, individual crystallins, and other genes such as BFSP1, BFSP2, EPHA2, GJA3, GJA8, LIM2, MIP, and TDRD7 represented in human cataract patients.
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Affiliation(s)
- Aleš Cvekl
- Departments Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Michael John Camerino
- Departments Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY 10461, USA
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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5
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van Heyningen V. A Journey Through Genetics to Biology. Annu Rev Genomics Hum Genet 2022; 23:1-27. [PMID: 35567277 DOI: 10.1146/annurev-genom-010622-095109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Although my engagement with human genetics emerged gradually, and sometimes serendipitously, it has held me spellbound for decades. Without my teachers, students, postdocs, colleagues, and collaborators, I would not be writing this review of my scientific adventures. Early gene and disease mapping was a satisfying puzzle-solving exercise, but building biological insight was my main goal. The project trajectory was hugely influenced by the evolutionarily conserved nature of the implicated genes and by the pace of progress in genetic technologies. The rich detail of clinical observations, particularly in eye disease, makes humans an excellent model, especially when complemented by the use of multiple other animal species for experimental validation. The contributions of collaborators and rivals also influenced our approach. We are very fortunate to work in this era of unprecedented progress in genetics and genomics. Expected final online publication date for the Annual Review of Genomics and Human Genetics, Volume 23 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Veronica van Heyningen
- UCL Institute of Ophthalmology, University College London, London, United Kingdom.,MRC Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, United Kingdom;
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6
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Rudd ML, Hansen NF, Zhang X, Urick ME, Zhang S, Merino MJ, Mullikin JC, Brody LC, Bell DW. KLF3 and PAX6 are candidate driver genes in late-stage, MSI-hypermutated endometrioid endometrial carcinomas. PLoS One 2022; 17:e0251286. [PMID: 35081118 PMCID: PMC8791453 DOI: 10.1371/journal.pone.0251286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 11/05/2021] [Indexed: 12/24/2022] Open
Abstract
Endometrioid endometrial carcinomas (EECs) are the most common histological subtype of uterine cancer. Late-stage disease is an adverse prognosticator for EEC. The purpose of this study was to analyze EEC exome mutation data to identify late-stage-specific statistically significantly mutated genes (SMGs), which represent candidate driver genes potentially associated with disease progression. We exome sequenced 15 late-stage (stage III or IV) non-ultramutated EECs and paired non-tumor DNAs; somatic variants were called using Strelka, Shimmer, SomaticSniper and MuTect. Additionally, somatic mutation calls were extracted from The Cancer Genome Atlas (TCGA) data for 66 late-stage and 270 early-stage (stage I or II) non-ultramutated EECs. MutSigCV (v1.4) was used to annotate SMGs in the two late-stage cohorts and to derive p-values for all mutated genes in the early-stage cohort. To test whether late-stage SMGs are statistically significantly mutated in early-stage tumors, q-values for late-stage SMGs were re-calculated from the MutSigCV (v1.4) early-stage p-values, adjusting for the number of late-stage SMGs tested. We identified 14 SMGs in the combined late-stage EEC cohorts. When the 14 late-stage SMGs were examined in the TCGA early-stage data, only Krüppel-like factor 3 (KLF3) and Paired box 6 (PAX6) failed to reach significance as early-stage SMGs, despite the inclusion of enough early-stage cases to ensure adequate statistical power. Within TCGA, nonsynonymous mutations in KLF3 and PAX6 were, respectively, exclusive or nearly exclusive to the microsatellite instability (MSI)-hypermutated molecular subgroup and were dominated by insertions-deletions at homopolymer tracts. In conclusion, our findings are hypothesis-generating and suggest that KLF3 and PAX6, which encode transcription factors, are MSI target genes and late-stage-specific SMGs in EEC.
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Affiliation(s)
- Meghan L. Rudd
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Nancy F. Hansen
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Xiaolu Zhang
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Mary Ellen Urick
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Suiyuan Zhang
- Computational and Statistical Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Maria J. Merino
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | | | - James C. Mullikin
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
- NIH Intramural Sequencing Center, National Human Genome Research Institute, National Institutes of Health, Rockville, Maryland, United States of America
| | - Lawrence C. Brody
- Medical Genomics and Metabolic Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Daphne W. Bell
- Cancer Genetics and Comparative Genomics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, United States of America
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7
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Blanco-Kelly F, Tarilonte M, Villamar M, Damián A, Tamayo A, Moreno-Pelayo MA, Ayuso C, Cortón M. Genetics and epidemiology of aniridia: Updated guidelines for genetic study. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2021; 96 Suppl 1:4-14. [PMID: 34836588 DOI: 10.1016/j.oftale.2021.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 02/13/2021] [Indexed: 12/16/2022]
Abstract
Aniridia is a panocular disease characterized by iris hypoplasia, accompanied by other ocular manifestations, with a high clinical variability and overlapping with different abnormalities of the anterior and posterior segment. This review focuses on the genetic features of this autosomal dominant pathology, which is caused by the haploinsufficiency of the PAX6 gene. Mutations causing premature stop codons are the most frequent among the wider mutational spectrum of PAX6, with more than 600 different mutations identified so far. Recent advances in next-generation sequencing (NGS) have increased the diagnostic yield in aniridia and contributed to elucidate new etiopathogenic mechanisms leading to PAX6 haploinsufficiency. Here, we also update good practices and recommendations to improve genetic testing and clinical management of aniridia using more cost-effective NGS analysis. Those new approaches also allow studying simultaneously both structural variants and point-mutations in PAX6 as well as other genes for differential diagnosis, simultaneously. Some patients with atypical phenotypes might present mutations in FOXC1 and PITX2, both genes causing a wide spectrum of anterior segment dysgenesis, or in ITPR1, which is responsible for a distinctive form of circumpupillary iris aplasia present in Gillespie syndrome, or other mutations in minor genes. Since aniridia can also associate extraocular anomalies, as it occurs in carriers of PAX6 and WT1 microdeletions leading to WAGR syndrome, genetic studies are crucial to assure a correct diagnosis and clinical management, besides allowing prenatal and preimplantational genetic testing in families.
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Affiliation(s)
- F Blanco-Kelly
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - M Tarilonte
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - M Villamar
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, Spain; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - A Damián
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - A Tamayo
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
| | - M A Moreno-Pelayo
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, Spain; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - C Ayuso
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - M Cortón
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, Spain; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain.
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8
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Berry V, Ionides A, Pontikos N, Moore AT, Quinlan RA, Michaelides M. Variants in PAX6, PITX3 and HSF4 causing autosomal dominant congenital cataracts. Eye (Lond) 2021; 36:1694-1701. [PMID: 34345029 PMCID: PMC9307513 DOI: 10.1038/s41433-021-01711-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/15/2021] [Accepted: 07/16/2021] [Indexed: 11/09/2022] Open
Abstract
Background Lens development is orchestrated by transcription factors. Disease-causing variants in transcription factors and their developmental target genes are associated with congenital cataracts and other eye anomalies. Methods Using whole exome sequencing, we identified disease-causing variants in two large British families and one isolated case with autosomal dominant congenital cataract. Bioinformatics analysis confirmed these disease-causing mutations as rare or novel variants, with a moderate to damaging pathogenicity score, with testing for segregation within the families using direct Sanger sequencing. Results Family A had a missense variant (c.184 G>A; p.V62M) in PAX6 and affected individuals presented with nuclear cataract. Family B had a frameshift variant (c.470–477dup; p.A160R*) in PITX3 that was also associated with nuclear cataract. A recurrent missense variant in HSF4 (c.341 T>C; p.L114P) was associated with congenital cataract in a single isolated case. Conclusions We have therefore identified novel variants in PAX6 and PITX3 that cause autosomal dominant congenital cataract.
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Affiliation(s)
- Vanita Berry
- UCL Institute of Ophthalmology, University College London, London, UK. .,Moorfields Eye Hospital NHS Foundation Trust, London, UK.
| | - Alex Ionides
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | | | - Roy A Quinlan
- School of Biological and Medical Sciences, University of Durham, Durham, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK. .,Moorfields Eye Hospital NHS Foundation Trust, London, UK.
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9
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Shen T, Qiu X, Lin X, Lin J, Li X, Chen Q, Pan L, Wang Z, Shen H, Zhang Q, Yan J. Missense mutation in the PAX6 gene can cause a complex mild variable phenotype predominated by concomitant strabismus. Ophthalmic Genet 2021; 43:88-96. [PMID: 34344282 DOI: 10.1080/13816810.2021.1961283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
PURPOSE We aimed to reveal the underlying genetic defect in a multigenerational Chinese family with autosomal dominant concomitant strabismus complicated by multiple ocular developmental abnormalities. METHODS Comprehensive ophthalmic examinations were performed in 14 patients and 24 healthy family members. Whole exome sequencing was performed, and Sanger sequencing was used to confirm the probable mutation in all the family members. RESULTS Concomitant strabismus was the predominant phenotype in the affected family members, although the patients also exhibited variable phenotypes, including nystagmus, mild iris abnormalities, myopia, cataract, and coloboma. An R208W mutation in PAX6 was identified as the pathogenic mutation in the affected family members. CONCLUSIONS We recommend considering PAX6 as a candidate gene in the diagnostic screen for familial concomitant strabismus in order to avoid missed diagnosis of the mild ocular abnormalities. Careful examinations of mild ocular phenotypes are necessary for an accurate diagnosis of varied ocular abnormalities in the families with the PAX6 mutation, and proper diagnosis can facilitate genetic and clinical counseling for affected patients.
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Affiliation(s)
- Tao Shen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xuan Qiu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xiaoming Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jing Lin
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xiuling Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qiwen Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Liuqing Pan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Zhonghao Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Huangxuan Shen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Jianhua Yan
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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10
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Blanco-Kelly F, Tarilonte M, Villamar M, Damián A, Tamayo A, Moreno-Pelayo MA, Ayuso C, Cortón M. Genetics and epidemiology of aniridia: Updated guidelines for genetic study. ARCHIVOS DE LA SOCIEDAD ESPANOLA DE OFTALMOLOGIA 2021; 96:S0365-6691(21)00124-6. [PMID: 34243981 DOI: 10.1016/j.oftal.2021.02.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 02/09/2021] [Accepted: 02/13/2021] [Indexed: 11/24/2022]
Abstract
Aniridia is a panocular disease characterized by iris hypoplasia, accompanied by other ocular manifestations, with a high clinical variability and overlapping with different abnormalities of the anterior and posterior segment. This review focuses on the genetic features of this autosomal dominant pathology, which is caused by the haploinsufficiency of the PAX6 gene. Mutations causing premature stop codons are the most frequent among the wider mutational spectrum of PAX6, with more than 600 different mutations identified so far. Recent advances in next-generation sequencing (NGS) have increased the diagnostic yield in aniridia and contributed to elucidate new etiopathogenic mechanisms leading to PAX6 haploinsufficiency. Here, we also update good practices and recommendations to improve genetic testing and clinical management of aniridia using more cost-effective NGS analysis. Those new approaches also allow studying simultaneously both structural variants and point-mutations in PAX6 as well as other genes for differential diagnosis, simultaneously. Some patients with atypical phenotypes might present mutations in FOXC1 and PITX2, both genes causing a wide spectrum of anterior segment dysgenesis, or in ITPR1, which is responsible for a distinctive form of circumpupillary iris aplasia present in Gillespie syndrome, or other mutations in minor genes. Since aniridia can also associate extraocular anomalies, as it occurs in carriers of PAX6 and WT1 microdeletions leading to WAGR syndrome, genetic studies are crucial to assure a correct diagnosis and clinical management, besides allowing prenatal and preimplantational genetic testing in families.
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Affiliation(s)
- F Blanco-Kelly
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, España; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, España
| | - M Tarilonte
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, España
| | - M Villamar
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, España; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, España
| | - A Damián
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, España
| | - A Tamayo
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, España
| | - M A Moreno-Pelayo
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, España; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, España
| | - C Ayuso
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, España; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, España
| | - M Cortón
- Departamento de Genética, Hospital Universitario Fundación Jiménez Díaz, Madrid, España; Área de Genética & Genómica, Instituto de Investigación Sanitaria - Fundación Jiménez Díaz - Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, España; Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, España.
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11
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Landsend ECS, Lagali N, Utheim TP. Congenital aniridia - A comprehensive review of clinical features and therapeutic approaches. Surv Ophthalmol 2021; 66:1031-1050. [PMID: 33675823 DOI: 10.1016/j.survophthal.2021.02.011] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 02/16/2021] [Accepted: 02/23/2021] [Indexed: 12/13/2022]
Abstract
Congenital aniridia is a rare genetic eye disorder with total or partial absence of the iris from birth. In most cases the genetic origin of aniridia is a mutation in the PAX6 gene, leading to involvement of most eye structures. Hypoplasia of the fovea is usually present and is associated with reduced visual acuity and nystagmus. Aniridia-associated keratopathy, glaucoma, and cataract are serious and progressive complications that can further reduce visual function. Treatment of the ocular complications of aniridia is challenging and has a high risk of side effects. New approaches such as stem cell therapy may, however, offer better prognoses. We describe the various ocular manifestations of aniridia, with a special focus on conditions that commonly require treatment. We also review the growing literature reporting systemic manifestations of the disease.
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Affiliation(s)
| | - Neil Lagali
- Department of Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden
| | - Tor P Utheim
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway; Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
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12
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Application of WES Towards Molecular Investigation of Congenital Cataracts: Identification of Novel Alleles and Genes in a Hospital-Based Cohort of South India. Int J Mol Sci 2020; 21:ijms21249569. [PMID: 33339270 PMCID: PMC7765966 DOI: 10.3390/ijms21249569] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2020] [Revised: 12/04/2020] [Accepted: 12/08/2020] [Indexed: 12/25/2022] Open
Abstract
Congenital cataracts are the prime cause for irreversible blindness in children. The global incidence of congenital cataract is 2.2–13.6 per 10,000 births, with the highest prevalence in Asia. Nearly half of the congenital cataracts are of familial nature, with a predominant autosomal dominant pattern of inheritance. Over 38 of the 45 mapped loci for isolated congenital or infantile cataracts have been associated with a mutation in a specific gene. The clinical and genetic heterogeneity of congenital cataracts makes the molecular diagnosis a bit of a complicated task. Hence, whole exome sequencing (WES) was utilized to concurrently screen all known cataract genes and to examine novel candidate factors for a disease-causing mutation in probands from 11 pedigrees affected with familial congenital cataracts. Analysis of the WES data for known cataract genes identified causative mutations in six pedigrees (55%) in PAX6, FYCO1 (two variants), EPHA2, P3H2,TDRD7 and an additional likely causative mutation in a novel gene NCOA6, which represents the first dominant mutation in this gene. This study identifies a novel cataract gene not yet linked to human disease. NCOA6 is a transcriptional coactivator that interacts with nuclear hormone receptors to enhance their transcriptional activator function.
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13
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Matsushita I, Morita H, Kondo H. Autosomal dominant foveal hypoplasia without visible macular abnormalities and PAX6 mutations. Jpn J Ophthalmol 2020; 64:635-641. [PMID: 32857266 DOI: 10.1007/s10384-020-00766-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 07/16/2020] [Indexed: 12/30/2022]
Abstract
PURPOSE Autosomal dominant foveal hypoplasia (FVH1) is a rare disorder associated with mutations in the PAX6 gene. As an isolated disease entity, FVH1 does not include ocular disorders such as aniridia, microphthalmia, albinism, and achromatopsia. However, it only includes isolated foveal hypoplasia and foveal hypoplasia with presenile cataract. The purpose of this report is to present our findings in four patients from two families with FVH1 without visible ophthalmic macular abnormalities. STUDY DESIGN A review of the medical records of two families with FVH1 and genetic confirmation of mutations in the PAX6 gene. METHODS Fundus photographs, optical coherence tomographic (OCT) and OCT angiographic (OCTA) images, and slit-lamp anterior segment findings were determined. The type of mutation of the PAX6 gene was determined. RESULTS A 3-year-old girl (Patient 1) had signs and symptoms of an impairment in the development of vision without other retinal abnormalities OU. OCT images showed a shallow foveal pit, and OCTA showed the absence of the foveal avascular zone. The second patient (Patient 2) was a 6-year-old girl with unilateral mild cataract and shallow foveal pits OU. Similar shallow foveal pits were found in her asymptomatic mother (Patient 3) and maternal grandfather (Patient 4). Although the iris and posterior fundus were normal, all patients with FVH1 had goniodysgenesis. Genetic testing of the PAX6 gene revealed that Patient 1 had a novel heterozygous mutation (p.Asn365Lys) as a de novo mutation, and Patients 2, 3 and 4 had a novel heterozygous mutation (p.Pro20Ser). CONCLUSIONS Heterozygous mutations in the PAX6 gene can cause FVH1 with nearly normal appearing macula. FVH1 is difficult to diagnose, but detailed observations of the foveal structure and vasculature, and detecting the presence of goniodysgenesis can be helpful in identifying patients with FVH1.
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Affiliation(s)
- Itsuka Matsushita
- Department of Ophthalmology, University of Occupational and Environmental Health, Japan, 1-1, Iseigaoka, Yahatanishiku, Kitakyushu, 807-8555, Japan
| | - Hirofumi Morita
- Department of Ophthalmology, University of Occupational and Environmental Health, Japan, 1-1, Iseigaoka, Yahatanishiku, Kitakyushu, 807-8555, Japan
| | - Hiroyuki Kondo
- Department of Ophthalmology, University of Occupational and Environmental Health, Japan, 1-1, Iseigaoka, Yahatanishiku, Kitakyushu, 807-8555, Japan.
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14
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Marakhonov AV, Voskresenskaya AA, Ballesta MJ, Konovalov FA, Vasilyeva TA, Blanco-Kelly F, Pozdeyeva NA, Kadyshev VV, López-González V, Guillen E, Ayuso C, Zinchenko RA, Corton M. Expanding the phenotype of CRYAA nucleotide variants to a complex presentation of anterior segment dysgenesis. Orphanet J Rare Dis 2020; 15:207. [PMID: 32791987 PMCID: PMC7427288 DOI: 10.1186/s13023-020-01484-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 07/26/2020] [Indexed: 12/20/2022] Open
Abstract
Background Mutations in CRYAA, which encodes the α-crystallin protein, are associated with a spectrum of congenital cataract–microcornea syndromes. Results In this study, we performed clinical examination and subsequent genetic analysis in two unrelated sporadic cases of different geographical origins presenting with a complex phenotype of ocular malformation. Both cases manifested bilateral microphthalmia and severe anterior segment dysgenesis, primarily characterized by congenital aphakia, microcornea, and iris hypoplasia/aniridia. NGS-based analysis revealed two novel single nucleotide variants occurring de novo and affecting the translation termination codon of the CRYAA gene, c.520T > C and c.521A > C. Both variants are predicted to elongate the C-terminal protein domain by one-third of the original length. Conclusions Our report not only expands the mutational spectrum of CRYAA but also identifies the genetic cause of the unusual ocular phenotype described in this report.
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Affiliation(s)
- Andrey V Marakhonov
- Research Centre for Medical Genetics, Moskvorechie Str., 1, Moscow, Russian Federation.
| | - Anna A Voskresenskaya
- Cheboksary Branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Cheboksary, Russian Federation
| | - Maria Jose Ballesta
- Medical Genetics Department, University Hospital Virgen de la Arrixaca, Murcia, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII - Instituto de Salud Carlos III, Madrid, Spain
| | - Fedor A Konovalov
- Independent Clinical Bioinformatics Laboratory, Moscow, Russian Federation
| | - Tatyana A Vasilyeva
- Research Centre for Medical Genetics, Moskvorechie Str., 1, Moscow, Russian Federation
| | - Fiona Blanco-Kelly
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII - Instituto de Salud Carlos III, Madrid, Spain.,Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Av. Reyes Católicos n° 2, 28040, Madrid, Spain
| | - Nadezhda A Pozdeyeva
- Cheboksary Branch of the S. Fyodorov Eye Microsurgery Federal State Institution, Cheboksary, Russian Federation
| | - Vitaly V Kadyshev
- Research Centre for Medical Genetics, Moskvorechie Str., 1, Moscow, Russian Federation
| | - Vanesa López-González
- Medical Genetics Department, University Hospital Virgen de la Arrixaca, Murcia, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII - Instituto de Salud Carlos III, Madrid, Spain
| | - Encarna Guillen
- Medical Genetics Department, University Hospital Virgen de la Arrixaca, Murcia, Spain.,Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII - Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Ayuso
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII - Instituto de Salud Carlos III, Madrid, Spain.,Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Av. Reyes Católicos n° 2, 28040, Madrid, Spain
| | - Rena A Zinchenko
- Research Centre for Medical Genetics, Moskvorechie Str., 1, Moscow, Russian Federation
| | - Marta Corton
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII - Instituto de Salud Carlos III, Madrid, Spain. .,Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital, Universidad Autónoma de Madrid (IIS-FJD, UAM), Av. Reyes Católicos n° 2, 28040, Madrid, Spain.
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15
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Williamson KA, Hall HN, Owen LJ, Livesey BJ, Hanson IM, Adams GGW, Bodek S, Calvas P, Castle B, Clarke M, Deng AT, Edery P, Fisher R, Gillessen-Kaesbach G, Heon E, Hurst J, Josifova D, Lorenz B, McKee S, Meire F, Moore AT, Parker M, Reiff CM, Self J, Tobias ES, Verheij JBGM, Willems M, Williams D, van Heyningen V, Marsh JA, FitzPatrick DR. Recurrent heterozygous PAX6 missense variants cause severe bilateral microphthalmia via predictable effects on DNA-protein interaction. Genet Med 2020; 22:598-609. [PMID: 31700164 PMCID: PMC7056646 DOI: 10.1038/s41436-019-0685-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 10/14/2019] [Accepted: 10/15/2019] [Indexed: 12/11/2022] Open
Abstract
PURPOSE Most classical aniridia is caused by PAX6 haploinsufficiency. PAX6 missense variants can be hypomorphic or mimic haploinsufficiency. We hypothesized that missense variants also cause previously undescribed disease by altering the affinity and/or specificity of PAX6 genomic interactions. METHODS We screened PAX6 in 372 individuals with bilateral microphthalmia, anophthalmia, or coloboma (MAC) from the Medical Research Council Human Genetics Unit eye malformation cohort (HGUeye) and reviewed data from the Deciphering Developmental Disorders study. We performed cluster analysis on PAX6-associated ocular phenotypes by variant type and molecular modeling of the structural impact of 86 different PAX6 causative missense variants. RESULTS Eight different PAX6 missense variants were identified in 17 individuals (15 families) with MAC, accounting for 4% (15/372) of our cohort. Seven altered the paired domain (p.[Arg26Gln]x1, p.[Gly36Val]x1, p.[Arg38Trp]x2, p.[Arg38Gln]x1, p.[Gly51Arg]x2, p.[Ser54Arg]x2, p.[Asn124Lys]x5) and one the homeodomain (p.[Asn260Tyr]x1). p.Ser54Arg and p.Asn124Lys were exclusively associated with severe bilateral microphthalmia. MAC-associated variants were predicted to alter but not ablate DNA interaction, consistent with the electrophoretic mobility shifts observed using mutant paired domains with well-characterized PAX6-binding sites. We found no strong evidence for novel PAX6-associated extraocular disease. CONCLUSION Altering the affinity and specificity of PAX6-binding genome-wide provides a plausible mechanism for the worse-than-null effects of MAC-associated missense variants.
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Affiliation(s)
- Kathleen A Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - H Nikki Hall
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Liusaidh J Owen
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Benjamin J Livesey
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Isabel M Hanson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | | | - Simon Bodek
- Department of Clinical Genetics, St Michael's Hospital, Southwell Street, Bristol, UK
| | - Patrick Calvas
- CHU Toulouse, Service de Génétique Médicale, Hôpital Purpan, Toulouse, France
| | - Bruce Castle
- Peninsula Clinical Genetics, Royal Devon and Exeter Hospitals (Heavitree), Exeter, UK
| | - Michael Clarke
- Newcastle Eye Centre, Newcastle upon Tyne Hospitals NHS Foundation Trust, Royal Victoria Infirmary, Newcastle Upon Tyne, UK
| | - Alexander T Deng
- Clinical Genetics, Guys and St Thomas NHS Trust, Great Maze Pond, London, UK
| | - Patrick Edery
- Hospices Civils de Lyon, Genetic Department and National HHT Reference Center, Femme-Mère-Enfants Hospital, Bron, France
| | - Richard Fisher
- Teeside Genetics Unit, The James Cook University Hospital, Middlesbrough, UK
| | | | - Elise Heon
- Department of Ophthalmology and Vision Sciences, Hospital for Sick Children, Toronto, ON, Canada
| | - Jane Hurst
- Department of Clinical Genetics, Great Ormond Street Hospital for Children, London, UK
| | - Dragana Josifova
- Clinical Genetics, Guys and St Thomas NHS Trust, Great Maze Pond, London, UK
| | - Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany
| | - Shane McKee
- Northern Ireland Regional Genetics Service (NIRGS), Belfast City Hospital, Belfast, UK
| | - Francoise Meire
- Department of Ophthalmology, Hôpital Universitaire des Enfants Reine Fabiola, Brussels, Belgium
| | | | - Michael Parker
- Department of Clinical Genetics, Sheffield Children's NHS Foundation Trust, Sheffield, UK
| | - Charlotte M Reiff
- Department of Ophthalmology, University of Freiburg, Freiburg, Germany
| | - Jay Self
- University Hospital Southampton, Southampton, UK
- Clinical and Experimental Sciences, University of Southampton, Southampton, UK
| | - Edward S Tobias
- Academic Medical Genetics and Pathology, University of Glasgow, Queen Elizabeth University Hospital, Glasgow, UK
| | - Joke B G M Verheij
- Department of Genetics, University of Groningen, University Medical Center, Groningen, The Netherlands
| | | | - Denise Williams
- Clinical Genetics Unit, Birmingham Women's Hospital, Birmingham, UK
| | - Veronica van Heyningen
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Joseph A Marsh
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - David R FitzPatrick
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK.
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16
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Abstract
Mutations in human PAX6 gene are associated with various congenital eye malformations including aniridia, foveal hypoplasia, and congenital nystagmus. These various phenotypes may depend on the mutation spectrums that can affect DNA-binding affinity, although this hypothesis is debatable. We screened PAX6 mutations in two unrelated patients with congenital nystagmus, and measured DNA-binding affinity through isothermal titration calorimetry (ITC). To elucidate phenotypic differences according to DNA-binding affinity, we also compared DNA-binding affinity among the previously reported PAX6 missense mutations within the linker region between two subdomains of the paired domain (PD). We identified two novel mutations of PAX6 gene: c.214 G > T (p.Gly72Cys) and c.249_250delinsCGC (p.Val84Alafs*8). Both were located within the linker region between the two subdomains of the PD. ITC measurement revealed that the mutation p.Val84Alafs*8 had no DNA-binding affinity, while the p.Gly72Cys mutation showed a decreased binding affinity (Kd = 0.58 μM) by approximately 1.4 times compared to the wild type-PAX6 (Kd = 0.41 μM). We also found that there was no close relationship between DNA-binding affinity and phenotypic differences. Our results suggest that the DNA-binding affinity alone might be insufficient to determine PAX6-related phenotypes, and that other modifier genes or environmental factors might affect phenotypes of the PAX6 gene.
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17
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Tarilonte M, Morín M, Ramos P, Galdós M, Blanco-Kelly F, Villaverde C, Rey-Zamora D, Rebolleda G, Muñoz-Negrete FJ, Tahsin-Swafiri S, Gener B, Moreno-Pelayo MA, Ayuso C, Villamar M, Corton M. Parental Mosaicism in PAX6 Causes Intra-Familial Variability: Implications for Genetic Counseling of Congenital Aniridia and Microphthalmia. Front Genet 2018; 9:479. [PMID: 30386378 PMCID: PMC6199369 DOI: 10.3389/fgene.2018.00479] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 09/26/2018] [Indexed: 11/17/2022] Open
Abstract
Mutations in PAX6 are involved in several developmental eye disorders. These disorders have considerable phenotypic variability, ranging from panocular forms of congenital aniridia and microphthalmia to isolated anomalies of the anterior or posterior segment. Here, we describe 3 families with variable inter-generational ocular expression of aniridia, iris coloboma, or microphthalmia, and an unusual transmission of PAX6 mutations from an unaffected or mildly affected parent; all of which raised suspicion of gonosomal mosaicism. We first identified two previously known nonsense mutations and one novel likely pathogenic missense variant in PAX6 in probands by means of targeted NGS. The subsequent segregation analysis by Sanger sequencing evidenced the presence of highly probable mosaic events in paternal blood samples. Mosaicism was further confirmed by droplet digital PCR analysis in several somatic tissues of mosaic fathers. Quantification of the mutant allele fraction in parental samples showed a marked deviation from 50%, with a range between 12 and 29% depending on cell type. Gonosomal mosaicsm was definitively confirmed in one of the families thanks to the availability of a sperm sample from the mosaic father. Thus, the recurrence risk in this family was estimated to be about one-third. This is the first report confirming parental PAX6 mosaicism as a cause of disease recurrence in aniridia and other related phenotypes. In addition, we demonstrated that post-zygotic mosaicism is a frequent and underestimated pathogenic mechanism in aniridia, explaining intra-familial phenotypic variability in many cases. Our findings may have substantial implications for genetic counseling in congenital aniridia. Thus, we also highlight the importance of comprehensive genetic screening of parents for new sporadic cases with aniridia or related developmental eye disease to more accurately assess recurrence risk. In conclusion, somatic and/or gonosomal mosaicism should be taken into consideration as a genetic factor to explain not only families with unaffected parents despite multiple affected children but also variable expressivity, apparent de novo cases, and even uncharacterized cases of aniridia and related developmental eye disorders, apparently lacking PAX6 mutations.
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Affiliation(s)
- María Tarilonte
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain
| | - Matías Morín
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Patricia Ramos
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Galdós
- Department of Ophthalmology, Cruces University Hospital, Bilbao, Spain
| | - Fiona Blanco-Kelly
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Cristina Villaverde
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Dolores Rey-Zamora
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Gema Rebolleda
- Department of Glaucoma, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Francisco J Muñoz-Negrete
- Department of Glaucoma, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain
| | - Saoud Tahsin-Swafiri
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Blanca Gener
- Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain.,Department of Genetics, BioCruces Health Research Institute, Cruces University Hospital, Bilbao, Spain
| | - Miguel-Angel Moreno-Pelayo
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Ayuso
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Manuela Villamar
- Servicio de Genética, Instituto Ramón y Cajal de Investigación Sanitaria, Hospital Universitario Ramón y Cajal, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Marta Corton
- Department of Genetics and Genomics, Instituto de Investigación Sanitaria de la Fundación Jiménez Díaz, University Hospital - Universidad Autónoma de Madrid, Madrid, Spain.,Centre for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
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18
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Plaisancié J, Tarilonte M, Ramos P, Jeanton-Scaramouche C, Gaston V, Dollfus H, Aguilera D, Kaplan J, Fares-Taie L, Blanco-Kelly F, Villaverde C, Francannet C, Goldenberg A, Arroyo I, Rozet JM, Ayuso C, Chassaing N, Calvas P, Corton M. Implication of non-coding PAX6 mutations in aniridia. Hum Genet 2018; 137:831-846. [PMID: 30291432 DOI: 10.1007/s00439-018-1940-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Accepted: 09/23/2018] [Indexed: 01/14/2023]
Abstract
There is an increasing implication of non-coding regions in pathological processes of genetic origin. This is partly due to the emergence of sophisticated techniques that have transformed research into gene expression by allowing a more global understanding of the genome, both at the genomic, epigenomic and chromatin levels. Here, we implemented the analysis of PAX6, whose coding loss-of-function variants are mainly implied in aniridia, by studying its non-coding regions (untranslated regions, introns and cis-regulatory sequences). In particular, we have taken advantage of the development of high-throughput approaches to screen the upstream and downstream regulatory regions of PAX6 in 47 aniridia patients without identified mutation in the coding sequence. This was made possible through the use of custom targeted resequencing and/or CGH array to analyze the entire PAX6 locus on 11p13. We found candidate variants in 30 of the 47 patients. 9/30 correspond to the well-known described 3' deletions encompassing SIMO and other enhancer elements. In addition, we identified numerous different variants in various non-coding regions, in particular untranslated regions. Among these latter, most of them demonstrated an in vitro functional effect using a minigene strategy, and 12/21 are thus considered as causative mutations or very likely to explain the phenotypes. This new analysis strategy brings molecular diagnosis to more than 90% of our aniridia patients. This study revealed an outstanding mutation pattern in non-coding PAX6 regions confirming that PAX6 remains the major gene for aniridia.
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Affiliation(s)
- Julie Plaisancié
- Service de Génétique Médicale, Pavillon Lefebvre, Hôpital Purpan, CHU Toulouse, Place du Dr Baylac, 31059, Toulouse Cedex 9, France.
- INSERM U1056, Université Toulouse III, Toulouse, France.
| | - M Tarilonte
- Department of Genetics, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - P Ramos
- Department of Genetics, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - C Jeanton-Scaramouche
- Service de Génétique Médicale, Pavillon Lefebvre, Hôpital Purpan, CHU Toulouse, Place du Dr Baylac, 31059, Toulouse Cedex 9, France
| | - V Gaston
- Service de Génétique Médicale, Pavillon Lefebvre, Hôpital Purpan, CHU Toulouse, Place du Dr Baylac, 31059, Toulouse Cedex 9, France
| | - H Dollfus
- Centre de Référence pour les affections rares en génétique ophtalmologique, CARGO, Filière SENSGENE, Hôpitaux Universitaires de Strasbourg, Strasbourg, France
| | - D Aguilera
- Department of Genetics, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - J Kaplan
- Laboratoire de Génétique Ophtalmologique INSERM U1163, Institut Imagine, Paris, France
| | - L Fares-Taie
- Laboratoire de Génétique Ophtalmologique INSERM U1163, Institut Imagine, Paris, France
| | - F Blanco-Kelly
- Department of Genetics, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - C Villaverde
- Department of Genetics, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - C Francannet
- Service de Génétique Médicale, CHU Estaing, Clermont-Ferrand, France
| | - A Goldenberg
- Service de Génétique, CHU de Rouen, Centre Normand de Génomique Médicale et Médecine Personnalisée, Rouen, France
| | - I Arroyo
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Department of Genetics, Hospital of Cáceres, Cáceres, Spain
| | - J M Rozet
- Laboratoire de Génétique Ophtalmologique INSERM U1163, Institut Imagine, Paris, France
| | - C Ayuso
- Department of Genetics, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - N Chassaing
- Service de Génétique Médicale, Pavillon Lefebvre, Hôpital Purpan, CHU Toulouse, Place du Dr Baylac, 31059, Toulouse Cedex 9, France
- INSERM U1056, Université Toulouse III, Toulouse, France
| | - P Calvas
- Service de Génétique Médicale, Pavillon Lefebvre, Hôpital Purpan, CHU Toulouse, Place du Dr Baylac, 31059, Toulouse Cedex 9, France
- INSERM U1056, Université Toulouse III, Toulouse, France
| | - M Corton
- Department of Genetics, Instituto de Investigacion Sanitaria-Fundacion Jimenez Diaz University Hospital-Universidad Autónoma de Madrid (IIS-FJD, UAM), Madrid, Spain
- Center for Biomedical Network Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
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The genetic architecture of aniridia and Gillespie syndrome. Hum Genet 2018; 138:881-898. [PMID: 30242502 PMCID: PMC6710220 DOI: 10.1007/s00439-018-1934-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Accepted: 09/06/2018] [Indexed: 12/13/2022]
Abstract
Absence of part or all of the iris, aniridia, is a feature of several genetically distinct conditions. This review focuses on iris development and then the clinical features and molecular genetics of these iris malformations. Classical aniridia, a panocular eye malformation including foveal hypoplasia, is the archetypal phenotype associated with heterozygous PAX6 loss-of-function mutations. Since this was identified in 1991, many genetic mechanisms of PAX6 inactivation have been elucidated, the commonest alleles being intragenic mutations causing premature stop codons, followed by those causing C-terminal extensions. Rarely, aniridia cases are associated with FOXC1, PITX2 and/or their regulatory regions. Aniridia can also occur as a component of many severe global eye malformations. Gillespie syndrome—a triad of partial aniridia, non-progressive cerebellar ataxia and intellectual disability—is phenotypically and genotypically distinct from classical aniridia. The causative gene has recently been identified as ITPR1. The same characteristic Gillespie syndrome-like iris, with aplasia of the pupillary sphincter and a scalloped margin, is seen in ACTA2-related multisystemic smooth muscle dysfunction syndrome. WAGR syndrome (Wilms tumour, aniridia, genitourinary anomalies and mental retardation/intellectual disability), is caused by contiguous deletion of PAX6 and WT1 on chromosome 11p. Deletions encompassing BDNF have been causally implicated in the obesity and intellectual disability associated with the condition. Lastly, we outline a genetic investigation strategy for aniridia in light of recent developments, suggesting an approach based principally on chromosomal array and gene panel testing. This strategy aims to test all known aniridia loci—including the rarer, life-limiting causes—whilst remaining simple and practical.
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20
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A novel PAX6 nonsense mutation identified in an Iranian family with various eye anomalies. J Curr Ophthalmol 2018; 30:234-238. [PMID: 30197953 PMCID: PMC6127359 DOI: 10.1016/j.joco.2017.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 11/18/2017] [Accepted: 12/12/2017] [Indexed: 12/03/2022] Open
Abstract
Purpose The aim of this study was to detect the genetic defects in a large pedigree of affected individuals with various phenotypes of ocular anomalies including partial aniridia, congenital cataract, and nystagmus. Methods The entire coding region of paired box gene 6 (PAX6) was amplified by polymerase chain reaction (PCR), sequenced, and compared with a GenBank database. Results A novel mutation (c.1170 C > T; p.Gln297X) was found in the proband and all affected members. This nonsense mutation leads to PAX6 protein truncation. Conclusions Our findings suggest that this novel mutation is most likely responsible for the pathogenesis of the congenital aniridia, cataract, and nystagmus in this pedigree. To the best of our knowledge, this is the first report of this mutation of PAX6 gene in a kindred pedigree with various ocular abnormalities.
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Yahalom C, Blumenfeld A, Hendler K, Wussuki-Lior O, Macarov M, Shohat M, Khateb S. Mild aniridia phenotype: an under-recognized diagnosis of a severe inherited ocular disease. Graefes Arch Clin Exp Ophthalmol 2018; 256:2157-2164. [PMID: 30167917 DOI: 10.1007/s00417-018-4119-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 08/13/2018] [Accepted: 08/23/2018] [Indexed: 01/30/2023] Open
Abstract
PURPOSE Aniridia is a rare panocular disorder caused by mutations in the PAX6 gene and characterized mainly by iris hypoplasia. Here, we present six families with a history of low vision/blindness with a previously undiagnosed mild aniridia phenotype with minimal iris changes. METHODS Retrospective case series of patients diagnosed with a subtle aniridia phenotype characterized by minimal iris abnormalities, foveal hypoplasia, and an identified mutation in PAX6. Data collection from patient's charts included ocular examination findings, visual acuity, refraction, and clinical pictures when available. Genetic analysis was performed by isolation of genomic DNA from peripheral blood. The main outcome was the identification of patients with mild aniridia harboring a PAX6 mutation. RESULTS In all six families, the phenotype included minimal corectopia and foveal hypoplasia; nystagmus was present in 10 out of 11 patients. A PAX6 mutation was identified in all six families; three of these mutations were identified previously, and three are novel mutations. All the mutations are located within the conventional 128-residue paired domain of PAX6. CONCLUSIONS A mild form of aniridia should be considered in the differential diagnosis of patients with low vision associated with mild iris abnormalities, nystagmus, and foveal hypoplasia. To ensure an accurate diagnosis of aniridia, minimal pupillary changes and/or incipient keratopathy should be examined. The broad phenotypic heterogeneity among aniridia leads to the fact that eye care clinicians must have a high index of suspicion for the disease when seeing undiagnosed low vision patients, because proper diagnosis can improve management as well as facilitate genetic testing and counselling.
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Affiliation(s)
- Claudia Yahalom
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, 91120, Jerusalem, Israel.
| | - Anat Blumenfeld
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, 91120, Jerusalem, Israel
| | - Karen Hendler
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, 91120, Jerusalem, Israel
| | - Orly Wussuki-Lior
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, 91120, Jerusalem, Israel
| | - Michal Macarov
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, 91120, Jerusalem, Israel
| | - Mordechai Shohat
- Medical Genetic Institute, Maccabi Health Services, Tel Aviv, Israel.,Bioinformatic Department, Cancer Center, Sheba Medical Center and Sackler School of Medicine, Tel Aviv University, Tel Aviv-Yafo, Israel
| | - Samer Khateb
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, 91120, Jerusalem, Israel
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22
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Li J, Leng Y, Han S, Yan L, Lu C, Luo Y, Zhang X, Cao L. Clinical and genetic characteristics of Chinese patients with familial or sporadic pediatric cataract. Orphanet J Rare Dis 2018; 13:94. [PMID: 29914532 PMCID: PMC6006596 DOI: 10.1186/s13023-018-0828-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 05/18/2018] [Indexed: 12/11/2022] Open
Abstract
Background Pediatric cataract is a clinically and genetically heterogeneous disease which is a significant cause of lifelong visual impairment and treatable blindness. Our study aims to investigate the genotype spectrum in a group of Chinese patients with pediatric cataract. Methods We enrolled 39 families with pediatric cataract from October 2015 to April 2016. DNA samples of the probands were analyzed by target next-generation sequencing. Variants were validated using Sanger sequencing in the probands and available family members. Results In our cohort of 39 cases with different types of pediatric cataract, 23 cases were found to harbor putative pathogenic variants in 15 genes: CRYAA, CRYBA1, CRYBA4, CRYBB1, CRYGC, CRYGD, MIP, GCNT2, IARS2, NHS, BCOR, BFSP2, FYCO1, MAF, and PAX6. The mutation detection rates in the familial and sporadic cases were 75 and 47.8%, respectively. Of the 23 causative variants, over half were novel. Conclusions This is a rare report of systematic mutation screening analysis of pediatric cataract in a comparably large cohort of Chinese patients. Our observations enrich the mutation spectrum of pediatric cataract. Next-generation sequencing provides significant diagnostic information for pediatric cataract cases, especially when considering sporadic and subtle syndromal cases. Electronic supplementary material The online version of this article (10.1186/s13023-018-0828-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jingyan Li
- The Research Center for Medical Genomics, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, College of Basic Medical Science, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Yunji Leng
- The Research Center for Medical Genomics, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, College of Basic Medical Science, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Shirui Han
- The Research Center for Medical Genomics, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, College of Basic Medical Science, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Lulu Yan
- The Research Center for Medical Genomics, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, College of Basic Medical Science, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Chaoxia Lu
- McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China
| | - Yang Luo
- The Research Center for Medical Genomics, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, College of Basic Medical Science, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China
| | - Xue Zhang
- The Research Center for Medical Genomics, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, College of Basic Medical Science, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China. .,McKusick-Zhang Center for Genetic Medicine, State Key Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100005, China.
| | - Lihua Cao
- The Research Center for Medical Genomics, Key Laboratory of Cell Biology, Ministry of Public Health, Key Laboratory of Medical Cell Biology, Ministry of Education, College of Basic Medical Science, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122, China.
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Mutation of IPO13 causes recessive ocular coloboma, microphthalmia, and cataract. Exp Mol Med 2018; 50:1-11. [PMID: 29700284 PMCID: PMC5938035 DOI: 10.1038/s12276-018-0079-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 01/22/2018] [Accepted: 02/14/2018] [Indexed: 11/12/2022] Open
Abstract
Ocular coloboma is a developmental structural defect of the eye that often occurs as complex ocular anomalies. However, its genetic etiology remains largely unexplored. Here we report the identification of mutation (c.331C>T, p.R111C) in the IPO13 gene in a consanguineous family with ocular coloboma, microphthalmia, and cataract by a combination of whole-exome sequencing and homozygosity mapping. IPO13 encodes an importin-B family protein and has been proven to be associated with the pathogenesis of coloboma and microphthalmia. We found that Ipo13 was expressed in the cornea, sclera, lens, and retina in mice. Additionally, the mRNA expression level of Ipo13 decreased significantly in the patient compared with its expression in a healthy individual. Morpholino-oligonucleotide-induced knockdown of ipo13 in zebrafish caused dose-dependent microphthalmia and coloboma, which is highly similar to the ocular phenotypes in the patient. Moreover, both visual motor response and optokinetic response were impaired severely. Notably, these ocular phenotypes in ipo13-deficient zebrafish could be rescued remarkably by full-length ipo13 mRNA, suggesting that the phenotypes observed in zebrafish were due to insufficient ipo13 function. Altogether, our findings demonstrate, for the first time, a new role of IPO13 in eye morphogenesis and that loss of function of IPO13 could lead to ocular coloboma, microphthalmia, and cataract in humans and zebrafish. In-depth genomic analysis of the family of a young man with severe visual impairment reveals a new gene involved in eye development. Ocular coloboma encompasses various hereditary disorders in which the eyes form improperly. Many of the underlying genetic factors remain unidentified. Researchers led by Zi-Bing Jin at Wenzhou Medical University in China sequenced the genes of 28-year-old man with a recessive form of ocular coloboma. By comparing these genetic data against equivalent genome sequences from his healthy parents, Jin’s team identified a gene called IPO13 as the culprit. IPO13 has not been linked to human disease before, but the researchers demonstrated that switching off IPO13 expression in zebrafish embryos gave rise to underdeveloped eyes with defects in the iris and cornea. These findings give clinicians another potential indicator for early diagnosis of ocular coloboma.
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Phenotypic Variation in a Four-Generation Family with Aniridia Carrying a Novel PAX6 Mutation. J Ophthalmol 2018; 2018:5978293. [PMID: 29850208 PMCID: PMC5904767 DOI: 10.1155/2018/5978293] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 02/05/2018] [Indexed: 12/14/2022] Open
Abstract
Aniridia is a congenital disease that affects almost all eye structures and is primarily caused by loss-of-function mutations in the PAX6 gene. The degree of vision loss in aniridia varies and is dependent on the extent of foveal, iris, and optic nerve hypoplasia and the presence of glaucoma, cataracts, and corneal opacification. Here, we describe a 4-generation family in which 7 individuals across 2 generations carry a novel disease-causing frameshift mutation (NM_000280.4(PAX6):c.565TC>T) in PAX6. This mutation results in an early stop codon in exon 8, which is predicted to cause nonsense-mediated decay of the truncated mRNA and a functionally null PAX6 allele. Family members with aniridia showed differences in multiple eye phenotypes including iris and optic nerve hypoplasia, congenital and acquired corneal opacification, glaucoma, and strabismus. Visual acuity ranged from 20/100 to less than 20/800. Patients who required surgical intervention for glaucoma or corneal opacification had worse visual outcomes. Our results show that family members carrying a novel PAX6 frameshift mutation have variable expressivity, leading to different ocular comorbidities and visual outcomes.
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Zazo Seco C, Plaisancié J, Lupasco T, Michot C, Pechmeja J, Delanne J, Cottereau E, Ayuso C, Corton M, Calvas P, Ragge N, Chassaing N. Identification of PITX3 mutations in individuals with various ocular developmental defects. Ophthalmic Genet 2018; 39:314-320. [PMID: 29405783 DOI: 10.1080/13816810.2018.1430243] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
BACKGROUND Congenital cataract displays large phenotypic (syndromic and isolated cataracts) and genetic heterogeneity. Mutations in several transcription factors involved in eye development, like PITX3, have been associated with congenital cataracts and anterior segment mesenchymal disorders. MATERIALS AND METHODS Targeted sequencing of 187 genes involved in ocular development was performed in 96 patients with mainly anophthalmia and microphthalmia. Additionally, Sanger sequencing analysis of PITX3 was performed on a second cohort of 32 index cases with congenital cataract and Peters anomaly and/or sclereocornea. RESULTS We described five families with four different PITX3 mutations, two of which were novel. In Family 1, the heterozygous recurrent c.640_656dup (p.Gly220Profs*95) mutation cosegregated with eye anomalies ranging from congenital cataract to Peters anomaly. In Family 2, the novel c.669del [p.(Leu225Trpfs*84)] mutation cosegregated with dominantly inherited eye anomalies ranging from posterior embryotoxon to congenital cataract in heterozygous carriers and congenital sclereocornea and cataract in a patient homozygous for this mutation. In Family 3, we identified the recurrent heterozygous c.640_656dup (p.Gly220Profs*95) mutation segregating with congenital cataract. In Family 4, the de novo c.582del [p.(Ile194Metfs*115)] mutation was identified in a patient with congenital cataract, microphthalmia, developmental delay and autism. In Family 5, the c.38G>A (p.Ser13Asn) mutation segregated dominantly in a family with Peters anomaly, which is a novel phenotype associated with the c.38G>A variant compared with the previously reported isolated congenital cataract. CONCLUSIONS Our study unveils different phenotypes associated with known and novel mutations in PITX3, which will improve the genetic counselling of patients and their families.
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Affiliation(s)
- Celia Zazo Seco
- a UDEAR , Université de Toulouse, UMRS 1056 INSERM-Université Paul Sabatier , Toulouse , France
| | - Julie Plaisancié
- a UDEAR , Université de Toulouse, UMRS 1056 INSERM-Université Paul Sabatier , Toulouse , France.,b Service de Génétique Médicale , Hôpital Purpan, CHU , Toulouse , France
| | - Tatiana Lupasco
- a UDEAR , Université de Toulouse, UMRS 1056 INSERM-Université Paul Sabatier , Toulouse , France
| | - Caroline Michot
- c INSERM UMR1163 Unit, Department of Genetics , Institut Imagine, Paris Descartes University-Sorbonne Paris Cité, Necker Enfants-Malades Hospital , Paris , France
| | - Jacmine Pechmeja
- d Service d'ophtalmologie , Hôpital Purpan, CHU , Toulouse , France
| | - Julian Delanne
- e Centre de Génétique et Centre de référence «Anomalies du Développement et Syndromes Malformatifs» , Hôpital d'Enfants, Centre Hospitalier Universitaire de Dijon , Dijon , France
| | | | - Carmen Ayuso
- g Genetics Service , IIS - Fundación Jiménez Díaz University Hospital, CIBERER, (IIS-FJD, UAM) , Madrid , Spain
| | - Marta Corton
- g Genetics Service , IIS - Fundación Jiménez Díaz University Hospital, CIBERER, (IIS-FJD, UAM) , Madrid , Spain
| | - Patrick Calvas
- a UDEAR , Université de Toulouse, UMRS 1056 INSERM-Université Paul Sabatier , Toulouse , France.,b Service de Génétique Médicale , Hôpital Purpan, CHU , Toulouse , France
| | - Nicola Ragge
- h Department of Biological and Medical Sciences, Faculty of Health and Life Sciences , Oxford Brookes University , Oxford , UK.,i West Midlands Regional Clinical Genetics Service and Birmingham Health Partners , Birmingham Women and Children's Hospital NHS Foundation Trust , Birmingham , UK
| | - Nicolas Chassaing
- a UDEAR , Université de Toulouse, UMRS 1056 INSERM-Université Paul Sabatier , Toulouse , France.,b Service de Génétique Médicale , Hôpital Purpan, CHU , Toulouse , France
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Landsend ES, Utheim ØA, Pedersen HR, Lagali N, Baraas RC, Utheim TP. The genetics of congenital aniridia—a guide for the ophthalmologist. Surv Ophthalmol 2018; 63:105-113. [DOI: 10.1016/j.survophthal.2017.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/07/2017] [Accepted: 09/11/2017] [Indexed: 01/10/2023]
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Remez LA, Onishi A, Menuchin-Lasowski Y, Biran A, Blackshaw S, Wahlin KJ, Zack DJ, Ashery-Padan R. Pax6 is essential for the generation of late-born retinal neurons and for inhibition of photoreceptor-fate during late stages of retinogenesis. Dev Biol 2017; 432:140-150. [PMID: 28993200 DOI: 10.1016/j.ydbio.2017.09.030] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/08/2016] [Accepted: 09/23/2017] [Indexed: 12/16/2022]
Abstract
In the developing retina, as in other regions of the CNS, neural progenitors give rise to individual cell types during discrete temporal windows. Pax6 is expressed in retinal progenitor cells (RPCs) throughout the course of retinogenesis, and has been shown to be required during early retinogenesis for generation of most early-born cell types. In this study, we examined the function of Pax6 in postnatal mouse retinal development. We found that Pax6 is essential for the generation of late-born interneurons, while inhibiting photoreceptor differentiation. Generation of bipolar interneurons requires Pax6 expression in RPCs, while Pax6 is required for the generation of glycinergic, but not for GABAergic or non-GABAergic-non-glycinergic (nGnG) amacrine cell subtypes. In contrast, overexpression of either full-length Pax6 or its 5a isoform in RPCs induces formation of cells with nGnG amacrine features, and suppresses generation of other inner retinal cell types. Moreover, overexpression of both Pax6 variants prevents photoreceptor differentiation, most likely by inhibiting Crx expression. Taken together, these data show that Pax6 acts in RPCs to control differentiation of multiple late-born neuronal cell types.
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Affiliation(s)
- Liv Aleen Remez
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| | - Akishi Onishi
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States
| | - Yotam Menuchin-Lasowski
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| | - Assaf Biran
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel
| | - Seth Blackshaw
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States
| | - Karl J Wahlin
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, United States
| | - Donlad J Zack
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States; Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States
| | - Ruth Ashery-Padan
- Department of Human Molecular Genetics and Biochemistry, Faculty of Medicine and Sagol School of Neuroscience, Tel-Aviv University, Tel Aviv, Israel.
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Lewis CJ, Hedberg-Buenz A, DeLuca AP, Stone EM, Alward WL, Fingert JH. Primary congenital and developmental glaucomas. Hum Mol Genet 2017; 26:R28-R36. [PMID: 28549150 PMCID: PMC5886473 DOI: 10.1093/hmg/ddx205] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/24/2017] [Accepted: 05/24/2017] [Indexed: 11/13/2022] Open
Abstract
Glaucoma is the leading cause of irreversible blindness worldwide. Although most glaucoma patients are elderly, congenital glaucoma and glaucomas of childhood are also important causes of visual disability. Primary congenital glaucoma (PCG) is isolated, non-syndromic glaucoma that occurs in the first three years of life and is a major cause of childhood blindness. Other early-onset glaucomas may arise secondary to developmental abnormalities, such as glaucomas that occur with aniridia or as part of Axenfeld-Rieger syndrome. Congenital and childhood glaucomas have strong genetic bases and disease-causing mutations have been discovered in several genes. Mutations in three genes (CYP1B1, LTBP2, TEK) have been reported in PCG patients. Axenfeld-Rieger syndrome is caused by mutations in PITX2 or FOXC1 and aniridia is caused by PAX6 mutations. This review discusses the roles of these genes in primary congenital glaucoma and glaucomas of childhood.
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Affiliation(s)
- Carly J. Lewis
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Adam Hedberg-Buenz
- Department of Molecular Physiology and Biophysics, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Adam P. DeLuca
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Edwin M. Stone
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - Wallace L.M. Alward
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
| | - John H. Fingert
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
- Stephen A. Wynn Institute for Vision Research, 3111B Medical Education and Research Facility, University of Iowa, Iowa City, IA 52242, USA
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Clinical utility gene card for: Aniridia. Eur J Hum Genet 2016; 24:ejhg201673. [PMID: 27381094 DOI: 10.1038/ejhg.2016.73] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/28/2016] [Accepted: 05/26/2016] [Indexed: 11/08/2022] Open
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Analysis of compound heterozygotes reveals that the mouse floxed Pax6 (tm1Ued) allele produces abnormal eye phenotypes. Transgenic Res 2016; 25:679-92. [PMID: 27240603 PMCID: PMC5023747 DOI: 10.1007/s11248-016-9962-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 05/13/2016] [Indexed: 01/27/2023]
Abstract
Analysis of abnormal phenotypes produced by different types of mutations has been crucial for our understanding of gene function. Some floxed alleles that retain a neomycin-resistance selection cassette (neo cassette) are not equivalent to wild-type alleles and provide useful experimental resources. Pax6 is an important developmental gene and the aim of this study was to determine whether the floxed Pax6tm1Ued (Pax6fl) allele, which has a retained neo cassette, produced any abnormal eye phenotypes that would imply that it differs from the wild-type allele. Homozygous Pax6fl/fl and heterozygous Pax6fl/+ mice had no overt qualitative eye abnormalities but morphometric analysis showed that Pax6fl/fl corneas tended be thicker and smaller in diameter. To aid identification of weak effects, we produced compound heterozygotes with the Pax6Sey-Neu (Pax6−) null allele. Pax6fl/− compound heterozygotes had more severe eye abnormalities than Pax6+/− heterozygotes, implying that Pax6fl differs from the wild-type Pax6+ allele. Immunohistochemistry showed that the Pax6fl/− corneal epithelium was positive for keratin 19 and negative for keratin 12, indicating that it was abnormally differentiated. This Pax6fl allele provides a useful addition to the existing Pax6 allelic series and this study demonstrates the utility of using compound heterozygotes with null alleles to unmask cryptic effects of floxed alleles.
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Ansari M, Rainger J, Hanson IM, Williamson KA, Sharkey F, Harewood L, Sandilands A, Clayton-Smith J, Dollfus H, Bitoun P, Meire F, Fantes J, Franco B, Lorenz B, Taylor DS, Stewart F, Willoughby CE, McEntagart M, Khaw PT, Clericuzio C, Van Maldergem L, Williams D, Newbury-Ecob R, Traboulsi EI, Silva ED, Madlom MM, Goudie DR, Fleck BW, Wieczorek D, Kohlhase J, McTrusty AD, Gardiner C, Yale C, Moore AT, Russell-Eggitt I, Islam L, Lees M, Beales PL, Tuft SJ, Solano JB, Splitt M, Hertz JM, Prescott TE, Shears DJ, Nischal KK, Doco-Fenzy M, Prieur F, Temple IK, Lachlan KL, Damante G, Morrison DA, van Heyningen V, FitzPatrick DR. Genetic Analysis of 'PAX6-Negative' Individuals with Aniridia or Gillespie Syndrome. PLoS One 2016; 11:e0153757. [PMID: 27124303 PMCID: PMC4849793 DOI: 10.1371/journal.pone.0153757] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Accepted: 04/04/2016] [Indexed: 12/26/2022] Open
Abstract
We report molecular genetic analysis of 42 affected individuals referred with a diagnosis of aniridia who previously screened as negative for intragenic PAX6 mutations. Of these 42, the diagnoses were 31 individuals with aniridia and 11 individuals referred with a diagnosis of Gillespie syndrome (iris hypoplasia, ataxia and mild to moderate developmental delay). Array-based comparative genomic hybridization identified six whole gene deletions: four encompassing PAX6 and two encompassing FOXC1. Six deletions with plausible cis-regulatory effects were identified: five that were 3' (telomeric) to PAX6 and one within a gene desert 5' (telomeric) to PITX2. Sequence analysis of the FOXC1 and PITX2 coding regions identified two plausibly pathogenic de novo FOXC1 missense mutations (p.Pro79Thr and p.Leu101Pro). No intragenic mutations were detected in PITX2. FISH mapping in an individual with Gillespie-like syndrome with an apparently balanced X;11 reciprocal translocation revealed disruption of a gene at each breakpoint: ARHGAP6 on the X chromosome and PHF21A on chromosome 11. In the other individuals with Gillespie syndrome no mutations were identified in either of these genes, or in HCCS which lies close to the Xp breakpoint. Disruption of PHF21A has previously been implicated in the causation of intellectual disability (but not aniridia). Plausibly causative mutations were identified in 15 out of 42 individuals (12/32 aniridia; 3/11 Gillespie syndrome). Fourteen of these mutations presented in the known aniridia genes; PAX6, FOXC1 and PITX2. The large number of individuals in the cohort with no mutation identified suggests greater locus heterogeneity may exist in both isolated and syndromic aniridia than was previously appreciated.
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Affiliation(s)
- Morad Ansari
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Jacqueline Rainger
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Isabel M. Hanson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Kathleen A. Williamson
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Freddie Sharkey
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Louise Harewood
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Angela Sandilands
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Jill Clayton-Smith
- Faculty of Medical and Human Sciences, Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester Academic Health Science Centre (MAHSC), Manchester, United Kingdom
| | - Helene Dollfus
- Service de Génétique Médicale, Hôpital de Haute-Pierre, Strasbourg, France
| | - Pierre Bitoun
- Medical Genetics Departments, University Hospital Jean Verdier, Bondy, France
| | - Francoise Meire
- Department of ophthalmopediatrics, Hôpital Universitaire des Enfants Reine Fabiola, Bruxelles, Belgium
| | - Judy Fantes
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - Brunella Franco
- Medical Genetics, Department of Medical Translational Sciences, Federico II University, Naples, Italy
- Telethon Institute of Genetics and Medicine (TIGEM), Pozzuoli, Italy
| | - Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig-University Giessen, Universitaetsklinikum Giessen and Marburg UKGM, Giessen, Germany
| | - David S. Taylor
- Institute of Child Health, University College London, UK and Great Ormond Street Hospital for Children, London, United Kingdom
| | - Fiona Stewart
- Northern Ireland Regional Genetics Service (NIRGS), Belfast City Hospital, Belfast, United Kingdom
| | - Colin E. Willoughby
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom
| | - Meriel McEntagart
- Medical Genetics Unit, St George's University of London, London, United Kingdom
| | - Peng Tee Khaw
- Moorfields Eye Hospital, London, UK and University College London, Institute of Ophthalmology, London, United Kingdom
| | - Carol Clericuzio
- Department of Pediatric Genetics, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | | | - Denise Williams
- Clinical Genetics Unit, Birmingham Women's Hospital, Birmingham, United Kingdom
| | - Ruth Newbury-Ecob
- Department of Clinical Genetics, University Hospitals, Bristol, United Kingdom
| | - Elias I. Traboulsi
- Center for Genetic Eye Diseases, Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, United States of America
| | - Eduardo D. Silva
- Department Ophthalmology, University Hospital of Coimbra, Coimbra, Portugal
| | - Mukhlis M. Madlom
- Children's Hospital, Doncaster Royal Infirmary, Doncaster, United Kingdom
| | - David R. Goudie
- Human Genetics Unit, University of Dundee College of Medicine, Dentistry and Nursing, Ninewells Hospital, Dundee, United Kingdom
| | - Brian W. Fleck
- Department of Ophthalmology, Princess Alexandra Eye Pavilion, Chalmers Street, Edinburgh, United Kingdom
| | - Dagmar Wieczorek
- Institut für Humangenetik, Universitätsklinikum Essen, Universität Duisburg-Essen, Essen, Germany
- Institut für Humangenetik, Universitätsklinikum Düsseldorf, Heinrich-Heine-Universität Düsseldorf, Düsseldorf, Germany
| | | | - Alice D. McTrusty
- Department of Life Sciences, Glasgow Caledonian University, Glasgow, United Kingdom
| | - Carol Gardiner
- Clinical Genetics, Southern General Hospital, Glasgow, United Kingdom
| | - Christopher Yale
- Department of Paediatrics and Child Health, Ipswich Hospital, Ipswich, United Kingdom
| | - Anthony T. Moore
- Moorfields Eye Hospital, London, UK and University College London, Institute of Ophthalmology, London, United Kingdom
| | - Isabelle Russell-Eggitt
- Institute of Child Health, University College London, UK and Great Ormond Street Hospital for Children, London, United Kingdom
| | - Lily Islam
- Institute of Child Health, University College London, UK and Great Ormond Street Hospital for Children, London, United Kingdom
| | - Melissa Lees
- North East Thames Regional Genetics Service, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street Hospital, London, United Kingdom
| | - Philip L. Beales
- Institute of Child Health, University College London, UK and Great Ormond Street Hospital for Children, London, United Kingdom
| | - Stephen J. Tuft
- Moorfields Eye Hospital, London, UK and University College London, Institute of Ophthalmology, London, United Kingdom
| | - Juan B. Solano
- Ruber International Hospital, Medical Genetics Unit, Mirasierra, Madrid, Spain
| | - Miranda Splitt
- Northern Genetics Service, Institute of Genetic Medicine, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, United Kingdom
| | - Jens Michael Hertz
- Department of Clinical Genetics, Odense University Hospital, Odense C, Denmark
| | - Trine E. Prescott
- Department of Medical Genetics, Oslo University Hospital, Oslo, Norway
| | - Deborah J. Shears
- Department of Clinical Genetics, Churchill Hospital, Oxford University Hospitals NHS Trust, Oxford, United Kingdom
| | - Ken K. Nischal
- UPMC Eye Center, Children's Hospital of Pittsburgh of UPMC, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | | | - Fabienne Prieur
- CHU de Saint Etienne, Service de génétique médicale, Saint-Etienne, France
| | - I. Karen Temple
- Academic Unit of Genetic Medicine, Division of Human Genetics, University of Southampton, Southampton, United Kingdom
| | - Katherine L. Lachlan
- Wessex Clinical Genetics Service, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Giuseppe Damante
- Department of Medical and Biological Sciences, University of Udine, Udine, Italy
| | - Danny A. Morrison
- St. Thomas’ Hospital, Westminster Bridge Road, London, United Kingdom
| | - Veronica van Heyningen
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
| | - David R. FitzPatrick
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom
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Cvekl A, Callaerts P. PAX6: 25th anniversary and more to learn. Exp Eye Res 2016; 156:10-21. [PMID: 27126352 DOI: 10.1016/j.exer.2016.04.017] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 04/12/2016] [Accepted: 04/22/2016] [Indexed: 01/29/2023]
Abstract
The DNA-binding transcription factor PAX6 was cloned 25 years ago by multiple teams pursuing identification of human and mouse eye disease causing genes, cloning vertebrate homologues of pattern-forming regulatory genes identified in Drosophila, or abundant eye-specific transcripts. Since its discovery in 1991, genetic, cellular, molecular and evolutionary studies on Pax6 mushroomed in the mid 1990s leading to the transformative thinking regarding the genetic program orchestrating both early and late stages of eye morphogenesis as well as the origin and evolution of diverse visual systems. Since Pax6 is also expressed outside of the eye, namely in the central nervous system and pancreas, a number of important insights into the development and function of these organs have been amassed. In most recent years, genome-wide technologies utilizing massively parallel DNA sequencing have begun to provide unbiased insights into the regulatory hierarchies of specification, determination and differentiation of ocular cells and neurogenesis in general. This review is focused on major advancements in studies on mammalian eye development driven by studies of Pax6 genes in model organisms and future challenges to harness the technology-driven opportunities to reconstruct, step-by-step, the transition from naïve ectoderm, neuroepithelium and periocular mesenchyme/neural crest cells into the three-dimensional architecture of the eye.
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Affiliation(s)
- Ales Cvekl
- The Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; The Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
| | - Patrick Callaerts
- Laboratory of Behavioral and Developmental Genetics, K.U. Leuven, VIB, 3000, Leuven, Belgium.
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Bobilev AM, McDougal ME, Taylor WL, Geisert EE, Netland PA, Lauderdale JD. Assessment of PAX6 alleles in 66 families with aniridia. Clin Genet 2016; 89:669-77. [PMID: 26661695 DOI: 10.1111/cge.12708] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Revised: 12/03/2015] [Accepted: 12/04/2015] [Indexed: 12/18/2022]
Abstract
We report on PAX6 alleles associated with a clinical diagnosis of classical aniridia in 81 affected individuals representing 66 families. Allelic variants expected to affect PAX6 function were identified in 61 families (76 individuals). Ten cases of sporadic aniridia (10 families) had complete (8 cases) or partial (2 cases) deletion of the PAX6 gene. Sequence changes that introduced a premature termination codon into the open reading frame of PAX6 occurred in 47 families (62 individuals). Three individuals with sporadic aniridia (three families) had sequence changes (one deletion, two run-on mutations) expected to result in a C-terminal extension. An intronic deletion of unknown functional significance was detected in one case of sporadic aniridia (one family), but not in unaffected relatives. Within these 61 families, single nucleotide substitutions accounted for 30/61 (49%), indels for 23/61 (38%), and complete deletion of the PAX6 locus for 8/61 (13%). In five cases of sporadic aniridia (five families), no disease-causing mutation in the coding region was detected. In total, 23 unique variants were identified that have not been reported in the Leiden Open Variation Database (LOVD) database. Within the group assessed, 92% had sequence changes expected to reduce PAX6 function, confirming the primacy of PAX6 haploinsufficiency as causal for aniridia.
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Affiliation(s)
- A M Bobilev
- Neuroscience Division of the Biomedical and Health Sciences Institute, The University of Georgia, Athens, GA, USA
| | - M E McDougal
- Department of Cellular Biology, The University of Georgia, Athens, GA, USA
| | - W L Taylor
- Molecular Resource Center, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - E E Geisert
- Department of Ophthalmology in the Hamilton Eye Institute, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - P A Netland
- Molecular Resource Center, The University of Tennessee Health Science Center, Memphis, TN, USA
| | - J D Lauderdale
- Neuroscience Division of the Biomedical and Health Sciences Institute, The University of Georgia, Athens, GA, USA.,Department of Cellular Biology, The University of Georgia, Athens, GA, USA
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Holmström G, Bondeson ML, Eriksson U, Åkerblom H, Larsson E. 'Congenital' nystagmus may hide various ophthalmic diagnoses. Acta Ophthalmol 2014; 92:412-6. [PMID: 23889849 DOI: 10.1111/aos.12250] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 06/29/2013] [Indexed: 01/23/2023]
Abstract
PURPOSE To investigate whether patients registered at a low-vision centre with 'nystagmus' had any underlying, but so far unknown, ophthalmic diagnosis. METHODS All patients registered at the low-vision centre of Uppsala county with nystagmus as their major diagnosis were identified. Their medical records were studied to exclude those with other general diagnoses that could explain the nystagmus. The remaining group of patients underwent an ophthalmic examination, refraction and optical coherence tomography (OCT). Electroretinogram and genetic analyses were performed when indicated. RESULTS Sixty-two patients with nystagmus as their main diagnosis were registered at the low-vision centre, Uppsala, and 43 of them had a major diagnosis other than nystagmus. Nystagmus was the major diagnosis in 19 patients, 15 of whom, aged 6-76 years, participated in the study. Two of the patients had foveal hypoplasia and albinism, four a seemingly isolated foveal hypoplasia, three achromatopsia, one rod-cone dystrophy, one degenerative high myopia, and two could not be evaluated. Only two patients appeared to have 'congenital' nystagmus. Eleven of the patients underwent a comprehensive genetic investigation of the PAX 6 gene. In addition, four of the patients were analysed for mutations in FOXC1 and PITX2 and one in FRMD7. No mutations were found in any of the patients analysed. CONCLUSION The study illustrates that many patients in our study group with nystagmus had underlying ophthalmic diagnoses. Early diagnosis is important to facilitate habilitation and to provide genetic counselling and, in the future, possibly also gene therapy.
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Affiliation(s)
- Gerd Holmström
- Department of Neuroscience/Ophthalmology, Uppsala University, Uppsala, Sweden
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36
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Blake JA, Ziman MR. Pax genes: regulators of lineage specification and progenitor cell maintenance. Development 2014; 141:737-51. [PMID: 24496612 DOI: 10.1242/dev.091785] [Citation(s) in RCA: 138] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Pax genes encode a family of transcription factors that orchestrate complex processes of lineage determination in the developing embryo. Their key role is to specify and maintain progenitor cells through use of complex molecular mechanisms such as alternate RNA splice forms and gene activation or inhibition in conjunction with protein co-factors. The significance of Pax genes in development is highlighted by abnormalities that arise from the expression of mutant Pax genes. Here, we review the molecular functions of Pax genes during development and detail the regulatory mechanisms by which they specify and maintain progenitor cells across various tissue lineages. We also discuss mechanistic insights into the roles of Pax genes in regeneration and in adult diseases, including cancer.
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Affiliation(s)
- Judith A Blake
- School of Medical Sciences, Edith Cowan University, Joondalup, WA 6027, Australia
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Novel and recurrent PITX3 mutations in Belgian families with autosomal dominant congenital cataract and anterior segment dysgenesis have similar phenotypic and functional characteristics. Orphanet J Rare Dis 2014; 9:26. [PMID: 24555714 PMCID: PMC3937428 DOI: 10.1186/1750-1172-9-26] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2013] [Accepted: 02/10/2014] [Indexed: 12/16/2022] Open
Abstract
Background Congenital cataracts are clinically and genetically heterogeneous with more than 45 known loci and 38 identified genes. They can occur as isolated defects or in association with anterior segment developmental anomalies. One of the disease genes for congenital cataract with or without anterior segment dysgenesis (ASD) is PITX3, encoding a transcription factor with a crucial role in lens and anterior segment development. Only five unique PITX3 mutations have been described, of which the 17-bp duplication c.640_656dup, p.(Gly220Profs*95), is the most common one and the only one known to cause cataract with ASD. The aim of this study was to perform a genetic study of the PITX3 gene in five probands with autosomal dominant congenital cataract (ADCC) and ASD, to compare their clinical presentations to previously reported PITX3-associated phenotypes and to functionally evaluate the PITX3 mutations found. Methods Sanger sequencing of the coding region and targeted exons of PITX3 was performed in probands and family members respectively. Transactivation, DNA-binding and subcellular localization assays were performed for the PITX3 mutations found. Ophthalmological examinations included visual acuity measurement, slit-lamp biomicroscopy, tonometry and fundoscopy. Results In four Belgian families with ADCC and ASD the recurrent 17-bp duplication c.640_656dup, p.(Gly220Profs*95), was found in a heterozygous state. A novel PITX3 mutation c.573del, p.(Ser192Alafs*117), was identified in heterozygous state in a Belgo-Romanian family with a similar phenotype. Functional assays showed that this novel mutation retains its nuclear localization but results in decreased DNA-binding and transactivation activity, similar to the recurrent duplication. Conclusions Our study identified a second PITX3 mutation leading to congenital cataract with ASD. The similarity in phenotypic expression was substantiated by our in vitro functional studies which demonstrated comparable molecular consequences for the novel p.(Ser192Alafs*117) and the recurrent p.(Gly220Profs*95) mutations.
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Thomas S, Thomas MG, Andrews C, Chan WM, Proudlock FA, McLean RJ, Pradeep A, Engle EC, Gottlob I. Autosomal-dominant nystagmus, foveal hypoplasia and presenile cataract associated with a novel PAX6 mutation. Eur J Hum Genet 2013; 22:344-9. [PMID: 23942204 DOI: 10.1038/ejhg.2013.162] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 05/12/2013] [Accepted: 05/15/2013] [Indexed: 11/09/2022] Open
Abstract
Autosomal-dominant idiopathic infantile nystagmus has been linked to 6p12 (OMIM 164100), 7p11.2 (OMIM 608345) and 13q31-q33 (OMIM 193003). PAX6 (11p13, OMIM 607108) mutations can also cause autosomal-dominant nystagmus, typically in association with aniridia or iris hypoplasia. We studied a large multigenerational white British family with autosomal-dominant nystagmus, normal irides and presenile cataracts. An SNP-based genome-wide analysis revealed a linkage to a 13.4-MB region on chromosome 11p13 with a maximum lod score of 2.93. A mutation analysis of the entire coding region and splice junctions of the PAX6 gene revealed a novel heterozygous missense mutation (c.227C>G) that segregated with the phenotype and is predicted to result in the amino-acid substitution of proline by arginine at codon 76 p.(P76R). The amino-acid variation p.(P76R) within the paired box domain is likely to destabilise the protein due to steric hindrance as a result of the introduction of a polar and larger amino acid. Eye movement recordings showed a significant intrafamilial variability of horizontal, vertical and torsional nystagmus. High-resolution in vivo imaging of the retina using optical coherence tomography (OCT) revealed features of foveal hypoplasia, including rudimentary foveal pit, incursion of inner retinal layers, short photoreceptor outer segments and optic nerve hypoplasia. Thus, this study presents a family that segregates a PAX6 mutation with nystagmus and foveal hypoplasia in the absence of iris abnormalities. Moreover, it is the first study showing detailed characteristics using eye movement recordings of autosomal-dominant nystagmus in a multigenerational family with a novel PAX6 mutation.
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Affiliation(s)
- Shery Thomas
- 1] Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK [2] Department of Ophthalmology, Nottingham University Hospital NHS Trust, Nottingham, UK
| | - Mervyn G Thomas
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Caroline Andrews
- 1] Department of Neurology, Ophthalmology, Medicine (Genetics), FM Kirby Neurobiology Center, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA [2] Department of Neurology, Harvard Medical School, Boston, MA, USA [3] Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Wai-Man Chan
- 1] Department of Neurology, Ophthalmology, Medicine (Genetics), FM Kirby Neurobiology Center, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA [2] Department of Neurology, Harvard Medical School, Boston, MA, USA [3] Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Frank A Proudlock
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Rebecca J McLean
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Archana Pradeep
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
| | - Elizabeth C Engle
- 1] Department of Neurology, Ophthalmology, Medicine (Genetics), FM Kirby Neurobiology Center, The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA, USA [2] Department of Neurology, Harvard Medical School, Boston, MA, USA [3] Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Irene Gottlob
- Ophthalmology Group, School of Medicine, University of Leicester, Leicester, UK
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Blanco-Kelly F, Villaverde-Montero C, Lorda-Sánchez I, Millán JM, Trujillo-Tiebas MJ, Ayuso C. Guidelines for genetic study of aniridia. ACTA ACUST UNITED AC 2012; 88:145-52. [PMID: 23597644 DOI: 10.1016/j.oftal.2012.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 04/24/2012] [Accepted: 07/10/2012] [Indexed: 10/27/2022]
Abstract
INTRODUCTION Aniridia is a panocular disorder which occurs in 1/50,000 to 1/100,000 live births and can appear either in isolated form or in the context of a syndrome. Isolated aniridia is inherited as an autosomal dominant condition and is caused by mutations of the PAX6 gene. A variety of techniques and methodologies within molecular genetics and cytogenetics are used to study these mutations. OBJECTIVE To identify the different aspects of this disease and to provide a guide for proper genetic diagnosis leading to improved clinical management of the disease. DEVELOPMENT Aniridia is an autosomal dominant disease that primarily affects the iris, though it can impact most of the ocular structures. The disease is mainly caused by mutations in the PAX6 gene located on chromosome 11p13 which encodes a transcription factor that is involved in the development of the eye. Genetic analysis of aniridia is complex and requires the use of both molecular genetics and cytogenetics techniques. These procedures are indicated in all cases of aniridia. It is important bear certain clinical and technical aspects in mind prior to starting analysis or providing genetic counseling for patients and their families. CONCLUSIONS The use of molecular genetic techniques in the genetic diagnosis of aniridia enables patients and their families to receive better clinical management.
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Affiliation(s)
- F Blanco-Kelly
- Servicio de Genética, Instituto de Investigación Sanitaria, Fundación Jiménez Díaz, Madrid, Spain.
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Abstract
Aniridia is a rare congenital disorder in which there is a variable degree of hypoplasia or the absence of iris tissue associated with multiple other ocular changes, some present from birth and some arising progressively over time. Most cases are associated with dominantly inherited mutations or deletions of the PAX6 gene. This article will review the clinical manifestations, the molecular basis including genotype-phenotype correlations, diagnostic approaches and management of aniridia.
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He Y, Pan Z, Luo F. A novel PAX6 mutation in Chinese patients with severe congenital aniridia. Curr Eye Res 2012; 37:879-83. [PMID: 22621390 DOI: 10.3109/02713683.2012.688165] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE We identified a novel mutation in Paired Box gene 6 (PAX6) and characterized its associated clinical features of severe ocular malformation in a Chinese family with congenital aniridia. METHODS We studied two patients with aniridia from a Chinese family. All patients and noncarriers in this family underwent full ophthalmologic, general and urinary examinations. Total genomic DNA was isolated from peripheral blood of two aniridia patients. PAX6 levels were determined by PCR and its mutational status was determined by sequencing. Direct sequencing detected variations in PAX6. RESULTS Patients had bilateral congenital nystagmus, anterior polar cataract, absence of iris tissue, and foveal hypoplasia with severely reduced visual acuity. A novel heterozygous PAX6 mutation in exon 6 c.662G>A (p.W100X) was identified which created a premature termination codon. This observed sequence alteration was not found in 100 normal controls and has not been previously reported. CONCLUSIONS We identified a novel PAX6 mutation in a family with severe ocular malformation. Our study expands the mutational spectrum of PAX6 and enriches our knowledge of the relationship between genotype and phenotype due to these mutations.
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Affiliation(s)
- Yan He
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmic and Visual Science Key Laboratory, Beijing, China
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Shaham O, Menuchin Y, Farhy C, Ashery-Padan R. Pax6: a multi-level regulator of ocular development. Prog Retin Eye Res 2012; 31:351-76. [PMID: 22561546 DOI: 10.1016/j.preteyeres.2012.04.002] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Revised: 04/19/2012] [Accepted: 04/24/2012] [Indexed: 02/08/2023]
Abstract
Eye development has been a paradigm for the study of organogenesis, from the demonstration of lens induction through epithelial tissue morphogenesis, to neuronal specification and differentiation. The transcription factor Pax6 has been shown to play a key role in each of these processes. Pax6 is required for initiation of developmental pathways, patterning of epithelial tissues, activation of tissue-specific genes and interaction with other regulatory pathways. Herein we examine the data accumulated over the last few decades from extensive analyses of biochemical modules and genetic manipulation of the Pax6 gene. Specifically, we describe the regulation of Pax6's expression pattern, the protein's DNA-binding properties, and its specific roles and mechanisms of action at all stages of lens and retinal development. Pax6 functions at multiple levels to integrate extracellular information and execute cell-intrinsic differentiation programs that culminate in the specification and differentiation of a distinct ocular lineage.
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Affiliation(s)
- Ohad Shaham
- Sackler Faculty of Medicine, Department of Human Molecular Genetics and Biochemistry, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel
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Shukla S, Mishra R. Predictions on impact of missense mutations on structure function relationship of PAX6 and its alternatively spliced isoform PAX6(5a). Interdiscip Sci 2012; 4:54-73. [PMID: 22392277 DOI: 10.1007/s12539-012-0114-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2010] [Revised: 04/11/2011] [Accepted: 05/17/2011] [Indexed: 05/31/2023]
Abstract
The PAX6 contains two DNA-binding domains, paired domain (PD), homeodomain (HD), and a transactivation domain (TD). Only the crystal structure of PD and the solution structure of HD of PAX6 are known. Mutations in PAX6 show variable penetrance, and expressivity of ocular and neural diseases, but the mechanism is poorly understood. Its alternatively spliced isoform PAX6(5a), is also required in a specific ratio for optimal functions. To understand impact of missense mutations on stability, and conformation of PAX6, whose functional analyses are described in PAX6 allelic variant database, were considered. Representative mutations like PAX6-L46R, -C52R, -V126D, -R128C, -R242T, -P375Q, -Q422R, -V256E, and -S259P from PD, HD, and TD of PAX6 were explored. The secondary structures were analyzed through PSIPRED, and relative solvent accessibilities (RSA) of the mutant and the wild type amino acid residues were compared through SABLE. The change in the contact residues and calculations of energy level were studied through SVMcon, MUpro, and FoldX, respectively. The 3D modeling was performed with the help of MODELLER and models were visualized in Chimera. Predictions suggest mutation induced alterations in local conformation or misfolding in DNA-binding domains of PAX6 and PAX6(5a). The predicted impact of mutations via secondary structure, changes in free energy, stability, conformation, and experimental reports on DNA-binding and transactivation, necessarily provides a strong background to explain structure-function relationship of PAX6 and PAX6(5a). However, because of their predictive nature, these findings need to be validated with other experimental evidences when structure of full length PAX6 is available.
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Affiliation(s)
- Sachin Shukla
- Department of Zoology, Banaras Hindu University, Varanasi, 221005, India
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Abstract
PURPOSE OF REVIEW Anterior segment dysgenesis (ASD) disorders encompass a spectrum of developmental conditions affecting the cornea, iris, and lens and are generally associated with an approximate 50% risk for glaucoma. These conditions are characterized by both autosomal dominant and recessive patterns of inheritance often with incomplete penetrance/variable expressivity. This article summarizes what is known about the genetics of ASD disorders and reviews recent developments. RECENT FINDINGS Mutations in Collagen type IV alpha-1 (COL4A1) and Beta-1,3-galactosyltransferase-like (B3GALTL) have been reported in ASD patients. Novel findings in other well known ocular genes are also presented, among which regulatory region deletions in PAX6 and PITX2 are most notable. SUMMARY Although a number of genetic causes have been identified, many ASD conditions are still awaiting genetic elucidation. The majority of characterized ASD genes encode transcription factors; several other genes represent extracellular matrix-related proteins. All of the involved genes play active roles in ocular development and demonstrate conserved functions across species. The use of novel technologies, such as whole genome sequencing/comparative genomic hybridization, is likely to broaden the mutation spectrums in known genes and assist in the identification of novel causative genes as well as modifiers explaining the phenotypic variability of ASD conditions.
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Mort RL, Bentley AJ, Martin FL, Collinson JM, Douvaras P, Hill RE, Morley SD, Fullwood NJ, West JD. Effects of aberrant Pax6 gene dosage on mouse corneal pathophysiology and corneal epithelial homeostasis. PLoS One 2011; 6:e28895. [PMID: 22220198 PMCID: PMC3248408 DOI: 10.1371/journal.pone.0028895] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Accepted: 11/16/2011] [Indexed: 11/18/2022] Open
Abstract
Background Altered dosage of the transcription factor PAX6 causes multiple human eye pathophysiologies. PAX6+/− heterozygotes suffer from aniridia and aniridia-related keratopathy (ARK), a corneal deterioration that probably involves a limbal epithelial stem cell (LESC) deficiency. Heterozygous Pax6+/Sey-Neu (Pax6+/−) mice recapitulate the human disease and are a good model of ARK. Corneal pathologies also occur in other mouse Pax6 mutants and in PAX77Tg/− transgenics, which over-express Pax6 and model human PAX6 duplication. Methodology/Principal Findings We used electron microscopy to investigate ocular defects in Pax6+/− heterozygotes (low Pax6 levels) and PAX77Tg/− transgenics (high Pax6 levels). As well as the well-documented epithelial defects, aberrant Pax6 dosage had profound effects on the corneal stroma and endothelium in both genotypes, including cellular vacuolation, similar to that reported for human macular corneal dystrophy. We used mosaic expression of an X-linked LacZ transgene in X-inactivation mosaic female (XLacZTg/−) mice to investigate corneal epithelial maintenance by LESC clones in Pax6+/− and PAX77Tg/− mosaic mice. PAX77Tg/− mosaics, over-expressing Pax6, produced normal corneal epithelial radial striped patterns (despite other corneal defects), suggesting that centripetal cell movement was unaffected. Moderately disrupted patterns in Pax6+/− mosaics were corrected by introducing the PAX77 transgene (in Pax6+/−, PAX77Tg/− mosaics). Pax6Leca4/+, XLacZTg/− mosaic mice (heterozygous for the Pax6Leca4 missense mutation) showed more severely disrupted mosaic patterns. Corrected corneal epithelial stripe numbers (an indirect estimate of active LESC clone numbers) declined with age (between 15 and 30 weeks) in wild-type XLacZTg/− mosaics. In contrast, corrected stripe numbers were already low at 15 weeks in Pax6+/− and PAX77Tg/− mosaic corneas, suggesting Pax6 under- and over-expression both affect LESC clones. Conclusions/Significance Pax6+/− and PAX77Tg/− genotypes have only relatively minor effects on LESC clone numbers but cause more severe corneal endothelial and stromal defects. This should prompt further investigations of the pathophysiology underlying human aniridia and ARK.
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Affiliation(s)
- Richard L. Mort
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Adam J. Bentley
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | - Francis L. Martin
- Centre for Biophotonics, Lancaster University, Lancaster, United Kingdom
| | - J. Martin Collinson
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Panagiotis Douvaras
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Robert E. Hill
- Medical Research Council Human Genetics Unit, Medical Research Council Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Steven D. Morley
- School of Clinical Sciences & Community Health, University of Edinburgh, Edinburgh, United Kingdom
| | - Nigel J. Fullwood
- Division of Biomedical and Life Sciences, Lancaster University, Lancaster, United Kingdom
| | - John D. West
- Division of Reproductive and Developmental Sciences, University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
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Luo F, Zhou L, Ma X, He Y, Zou L, Jie Y, Liu J, Pan Z. Mutation analysis of PAX6 in a Chinese family and a patient with a presumed sporadic case of congenital aniridia. Ophthalmic Res 2011; 47:27-31. [PMID: 21691140 DOI: 10.1159/000327593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2009] [Accepted: 03/17/2011] [Indexed: 11/19/2022]
Abstract
AIMS Mutations in the PAX6 are the major cause of congenital aniridia. The objective of this study was to analyze genetic mutations in PAX6 in Chinese patients with congenital aniridia. METHODS Total genomic DNA was isolated from the peripheral blood of the aniridia patients, all healthy family members and 100 healthy volunteers. The 14 exons (including alternatively spliced exon 5a) of the PAX6 gene were amplified by polymerase chain reaction, and the products were sequenced to identify the mutation. RESULTS Two mutations of PAX6 were detected in exon 11 in the congenital aniridia patients. One mutation was caused by the duplication of the 4 nucleic acids CTCC (c.1286insCTCC), which would lead to a frameshift. The other mutation was caused by a transition from C to T (c.1311C → T), which would generate a stop codon. Neither mutation was present in the healthy family members or 100 healthy volunteers. CONCLUSION We examined the exon sequence of the PAX6 gene in a Chinese family and an unrelated individual with aniridia. The predicted outcome of both mutations is premature termination. The mutation found in the unrelated individual has not previously been reported and represents a new addition to the spectrum of mutations in PAX6.
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Affiliation(s)
- Fei Luo
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology and Visual Science Key Laboratory, Beijing, China
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Functional analysis of missense mutations G36A and G51A in PAX6, and PAX6(5a) causing ocular anomalies. Exp Eye Res 2011; 93:40-9. [PMID: 21524647 DOI: 10.1016/j.exer.2011.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 04/02/2011] [Accepted: 04/05/2011] [Indexed: 12/26/2022]
Abstract
The PAX6 has been described a "master regulator of eye development". A specific ratio of PAX6, and its alternatively spliced isoform, PAX6(5a), has also been observed essential for optimal function. Mutations into PAX6 lead to a number of ocular, and neuronal defects of variable penetrance and expressivity but the mechanism is either poorly understood or underrepresented. This report describes analysis of functions of two missense mutations, G36A, and G51A, causing optic-nerve hypoplasia and optic-disc coloboma in humans, respectively. Mutations were created by site-directed mutagenesis. Products were detected by in-vitro translation and transient transfection to the cultured NIH-3T3 cells. Their DNA-binding, and transcriptional activation properties were analysed through electrophoretic mobility shift assay and luciferase reporter assay, respectively. Mutations induced changes in conformation and secondary structure of PAX6, and PAX6(5a) not only restrict to specific site of mutation in the paired-domain but extend to homeodomain, and transactivation domain. The PAX6-G36A showed reduced binding to PAX6-consensus binding sequence and PAX6(5a)-consensus binding sequence but its binding affinity to homeodomain binding sequence was unaffected. It showed significantly higher transactivation potential through PAX6-consensus binding sequence but reduced activity with PAX6(5a)-consensus binding sequence and homeodomain binding sequence containing luciferase reporters. The PAX6(5a)-G36A showed enhanced transactivation potential with PAX6-consensus binding sequence, PAX6(5a)-consensus binding sequence, and homeodomain binding sequence containing luciferase reporters. The binding affinity of PAX6(5a)-G36A was significantly higher to PAX6-consensus binding sequence, and PAX6(5a)-consensus binding sequence as compared to PAX6(5a) but remains unaffected to homeodomain binding sequence. The enhanced binding affinity was observed by PAX6-G51A to PAX6-consensus binding sequence, PAX6(5a)-consensus binding sequence, and homeodomain binding sequence. The transactivation potential was observed higher with PAX6-consensus binding sequence but significant reduction was evident with PAX6(5a)-consensus binding sequence, and homeodomain binding sequence containing luciferase reporters. The lower binding affinity to PAX6-consensus binding sequence and PAX6(5a)-consensus binding sequence was observed by PAX6(5a)-G51A but loss of binding affinity was detected to homeodomain binding sequence. However, PAX6(5a)-G51A showed significantly higher transactivation with PAX6-consensus binding sequence, PAX6(5a)-consensus binding sequence, and homeodomain binding sequence containing luciferase reporters. With the eye-specific α-A-crystallin promoter, PAX6-G36A and PAX6-G51A mutants were found to have higher ability to transactivate whereas PAX6(5a)-G36A and PAX6(5a)-G51A have lower transactivation potential compared to their respective wild type forms. Thus, variable DNA-binding and transactivation properties of the mutants with different PAX6-binding sequences provide an insight towards their variable penetrance and expressivity.
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Ye W, Lin W, Tartakoff AM, Tao T. Karyopherins in nuclear transport of homeodomain proteins during development. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1654-62. [PMID: 21256166 DOI: 10.1016/j.bbamcr.2011.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 12/08/2010] [Accepted: 01/09/2011] [Indexed: 01/12/2023]
Abstract
Homeodomain proteins are crucial transcription factors for cell differentiation, cell proliferation and organ development. Interestingly, their homeodomain signature structure is important for both their DNA-binding and their nucleocytoplasmic trafficking. The accurate nucleocytoplasmic distribution of these proteins is essential for their functions. We summarize information on (a) the roles of karyopherins for import and export of homeoproteins, (b) the regulation of their nuclear transport during development, and (c) the corresponding complexity of homeoprotein nucleocytoplasmic transport signals. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Wenduo Ye
- Xiamen University School of Life Sciences, Xiamen, Fujian 361005, China
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Wenzel PL, Chong JL, Sáenz-Robles MT, Ferrey A, Hagan JP, Gomez YM, Rajmohan R, Sharma N, Chen HZ, Pipas JM, Robinson ML, Leone G. Cell proliferation in the absence of E2F1-3. Dev Biol 2010; 351:35-45. [PMID: 21185283 DOI: 10.1016/j.ydbio.2010.12.025] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2010] [Revised: 12/06/2010] [Accepted: 12/15/2010] [Indexed: 01/09/2023]
Abstract
E2F transcription factors regulate the progression of the cell cycle by repression or transactivation of genes that encode cyclins, cyclin dependent kinases, checkpoint regulators, and replication proteins. Although some E2F functions are independent of the Retinoblastoma tumor suppressor (Rb) and related family members, p107 and p130, much of E2F-mediated repression of S phase entry is dependent upon Rb. We previously showed in cultured mouse embryonic fibroblasts that concomitant loss of three E2F activators with overlapping functions (E2F1, E2F2, and E2F3) triggered the p53-p21(Cip1) response and caused cell cycle arrest. Here we report on a dramatic difference in the requirement for E2F during development and in cultured cells by showing that cell cycle entry occurs normally in E2f1-3 triply-deficient epithelial stem cells and progenitors of the developing lens. Sixteen days after birth, however, massive apoptosis in differentiating epithelium leads to a collapse of the entire eye. Prior to this collapse, we find that expression of cell cycle-regulated genes in E2F-deficient lenses is aberrantly high. In a second set of experiments, we demonstrate that E2F3 ablation alone does not cause abnormalities in lens development but rescues phenotypic defects caused by loss of Rb, a binding partner of E2F known to recruit histone deacetylases, SWI/SNF and CtBP-polycomb complexes, methyltransferases, and other co-repressors to gene promoters. Together, these data implicate E2F1-3 in mediating transcriptional repression by Rb during cell cycle exit and point to a critical role for their repressive functions in cell survival.
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Affiliation(s)
- Pamela L Wenzel
- Department of Molecular Virology, Immunology and Medical Genetics, Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH 43210, USA
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Cross SH, McKie L, West K, Coghill EL, Favor J, Bhattacharya S, Brown SDM, Jackson IJ. The Opdc missense mutation of Pax2 has a milder than loss-of-function phenotype. Hum Mol Genet 2010; 20:223-34. [PMID: 20943750 PMCID: PMC3005898 DOI: 10.1093/hmg/ddq457] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Renal-coloboma syndrome, also known as papillorenal syndrome, is an autosomal dominant human disorder in which optic disc coloboma is associated with kidney abnormalities. Mutations in the paired domain transcription factor PAX2 have been found to be the underlying cause of this disease. Disease severity varies between patients, and in some cases, renal hypoplasia has been found in the absence of any retinal defects. Here we report an N-ethyl-N-nitrosourea-induced mouse mutation, Opdc, which is an isoleucinetothreonine missense mutation, I40T, in the first α-helix of the Pax2 paired domain. The mutant protein binds target DNA sequences less strongly than the wild-type protein and acts poorly to transactivate target promoters in culture. The phenotypic consequence of this mutation on the development of the eye and ear is similar to that reported for null alleles of Pax2. However, in homozygotes, cerebellar development is normal on a genetic background in which loss of Pax2 results in failure of cerebellar formation. Moreover, there is a genetic background effect on the heterozygous phenotype such that on some strain backgrounds, kidney development is unaffected. Opdc is the first hypomorphic mutation reported for Pax2 that differs in phenotype from loss-of-function mutations. These results suggest that PAX2 is a strong candidate gene for cases in which human patients have optic disc coloboma not associated with renal dysplasia.
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Affiliation(s)
- Sally H Cross
- MRC Human Genetics Unit, Institute of Genetics and Molecular Medicine, Edinburgh, UK.
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