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Maxwell G, Souzeau E. Childhood glaucoma: Implications for genetic counselling. Clin Genet 2024. [PMID: 39206700 DOI: 10.1111/cge.14603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 07/17/2024] [Accepted: 07/23/2024] [Indexed: 09/04/2024]
Abstract
Childhood glaucoma is a heterogeneous group of ocular disorders defined by an age of onset from birth to 18 years. These vision-threatening disorders require early diagnosis, timely treatment, and lifelong management to maintain vision and minimise irreversible blindness. The genetics of childhood glaucoma is complex with both phenotypic and genetic heterogeneity. The purpose of this review is to summarise the different types of childhood glaucoma and their genetic architecture to aid in the genetic counselling process with patients and their families. We provide an overview of associated syndromes and discuss implications for genetic counselling, including genetic testing strategies, cascade genetic testing, and reproductive options.
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Affiliation(s)
- Giorgina Maxwell
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
| | - Emmanuelle Souzeau
- Department of Ophthalmology, Flinders University, Adelaide, South Australia, Australia
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2
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Hall HN, Parry D, Halachev M, Williamson KA, Donnelly K, Campos Parada J, Bhatia S, Joseph J, Holden S, Prescott TE, Bitoun P, Kirk EP, Newbury-Ecob R, Lachlan K, Bernar J, van Heyningen V, FitzPatrick DR, Meynert A. Short-read whole genome sequencing identifies causative variants in most individuals with previously unexplained aniridia. J Med Genet 2024; 61:250-261. [PMID: 38050128 PMCID: PMC7615962 DOI: 10.1136/jmg-2023-109181] [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: 03/12/2023] [Accepted: 09/25/2023] [Indexed: 12/06/2023]
Abstract
BACKGROUND Classic aniridia is a highly penetrant autosomal dominant disorder characterised by congenital absence of the iris, foveal hypoplasia, optic disc anomalies and progressive opacification of the cornea. >90% of cases of classic aniridia are caused by heterozygous, loss-of-function variants affecting the PAX6 locus. METHODS Short-read whole genome sequencing was performed on 51 (39 affected) individuals from 37 different families who had screened negative for mutations in the PAX6 coding region. RESULTS Likely causative mutations were identified in 22 out of 37 (59%) families. In 19 out of 22 families, the causative genomic changes have an interpretable deleterious impact on the PAX6 locus. Of these 19 families, 1 has a novel heterozygous PAX6 frameshift variant missed on previous screens, 4 have single nucleotide variants (SNVs) (one novel) affecting essential splice sites of PAX6 5' non-coding exons and 2 have deep intronic SNV (one novel) resulting in gain of a donor splice site. In 12 out of 19, the causative variants are large-scale structural variants; 5 have partial or whole gene deletions of PAX6, 3 have deletions encompassing critical PAX6 cis-regulatory elements, 2 have balanced inversions with disruptive breakpoints within the PAX6 locus and 2 have complex rearrangements disrupting PAX6. The remaining 3 of 22 families have deletions encompassing FOXC1 (a known cause of atypical aniridia). Seven of the causative variants occurred de novo and one cosegregated with familial aniridia. We were unable to establish inheritance status in the remaining probands. No plausibly causative SNVs were identified in PAX6 cis-regulatory elements. CONCLUSION Whole genome sequencing proves to be an effective diagnostic test in most individuals with previously unexplained aniridia.
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Affiliation(s)
- Hildegard Nikki Hall
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
| | - David Parry
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
- Illumina United Kingdom, Edinburgh, UK
| | - Mihail Halachev
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
| | - Kathleen A Williamson
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
| | - Kevin Donnelly
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
| | - Jose Campos Parada
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
| | - Shipra Bhatia
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
| | - Jeffrey Joseph
- MRC Human Genetics Unit, The University of Edinburgh, Edinburgh, UK
| | - Simon Holden
- East Anglia Regional Genetics Service, Addenbrooke's Hospital, Cambridge, UK
| | - Trine E Prescott
- Department of Medical Genetics, Telemark Hospital, Skien, Norway
| | - Pierre Bitoun
- Consultations de Génétique médicale, Service de Pédiatrie, CHU Paris-Nord, Hôpital Jean Verdier, Bondy, France
| | - Edwin P Kirk
- Centre for Clinical Genetics, Sydney Children's Hospital Randwick, Randwick, New South Wales, Australia
| | - Ruth Newbury-Ecob
- Department of Clinical Genetics, University Hospitals Bristol NHS Foundation Trust, Bristol, UK
| | - Katherine Lachlan
- University Hospital Southampton, NHS Foundation Trust Wessex Clinical Genetics Service, Southampton, UK
| | - Juan Bernar
- Department of Genetics, Hospital Ruber Internacional, Madrid, Spain
| | - Veronica van Heyningen
- MRC Human Genetics Unit, The University of Edinburgh, Edinburgh, UK
- Institute of Ophthalmology, University College London, London, UK
| | - David R FitzPatrick
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
| | - Alison Meynert
- Institute of Genetics and Cancer, The University of Edinburgh MRC Human Genetics Unit, Edinburgh, UK
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Cole JD, McDaniel JA, Nilak J, Ban A, Rodriguez C, Hameed Z, Grannonico M, Netland PA, Yang H, Provencio I, Liu X. Characterization of neural damage and neuroinflammation in Pax6 small-eye mice. Exp Eye Res 2024; 238:109723. [PMID: 37979905 PMCID: PMC10843716 DOI: 10.1016/j.exer.2023.109723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 10/17/2023] [Accepted: 11/07/2023] [Indexed: 11/20/2023]
Abstract
Aniridia is a panocular condition characterized by a partial or complete loss of the iris. It manifests various developmental deficits in both the anterior and posterior segments of the eye, leading to a progressive vision loss. The homeobox gene PAX6 plays an important role in ocular development and mutations of PAX6 have been the main causative factors for aniridia. In this study, we assessed how Pax6-haploinsufficiency affects retinal morphology and vision of Pax6Sey mice using in vivo and ex vivo metrics. We used mice of C57BL/6 and 129S1/Svlmj genetic backgrounds to examine the variable severity of symptoms as reflected in human aniridia patients. Elevated intraocular pressure (IOP) was observed in Pax6Sey mice starting from post-natal day 20 (P20). Correspondingly, visual acuity showed a steady age-dependent decline in Pax6Sey mice, though these phenotypes were less severe in the 129S1/Svlmj mice. Local retinal damage with layer disorganization was assessed at P30 and P80 in the Pax6Sey mice. Interestingly, we also observed a greater number of activated Iba1+ microglia and GFAP + astrocytes in the Pax6Sey mice than in littermate controls, suggesting a possible neuroinflammatory response to Pax6 deficiencies.
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Affiliation(s)
- James D Cole
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA; Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - John A McDaniel
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Joelle Nilak
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Ashley Ban
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Carlos Rodriguez
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Zuhaad Hameed
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Marta Grannonico
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Peter A Netland
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Hu Yang
- Linda and Bipin Doshi Department of Chemical and Biochemical Engineering, Missouri University of Science and Technology, Rolla, MO, USA
| | - Ignacio Provencio
- Department of Biology, University of Virginia, Charlottesville, VA, USA; Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA; Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, USA.
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA; Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA; Program in Fundamental Neuroscience, University of Virginia, Charlottesville, VA, USA; Department of Psychology, University of Virginia, Charlottesville, VA, USA.
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4
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Wang Q, Wei WB, Shi XY, Rong WN. A novel PAX6 variant as the cause of aniridia in a Chinese patient with SRRRD. BMC Med Genomics 2023; 16:182. [PMID: 37542296 PMCID: PMC10401864 DOI: 10.1186/s12920-023-01620-w] [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: 01/27/2023] [Accepted: 07/30/2023] [Indexed: 08/06/2023] Open
Abstract
BACKGROUND The genotype characteristics and their associated clinical phenotypes in patients with aniridia were analyzed to explore pathogenic variants using whole-exome sequencing. METHODS One patient with aniridia was enrolled at the Beijing Tongren Hospital. Comprehensive ophthalmic and general examinations were performed on the patient. DNA was extracted from the patient, and whole-exome sequencing was performed to identify the causative variant. The pathogenicity of the variant was predicted using in silico analysis and evaluated according to American College of Medical Genetics and Genomics guidelines. Relationships between genetic variants and clinical features were analyzed. RESULTS In addition to the classical aniridia phenotype showing complete iris aplasia, foveal hypoplasia, and ectopic lentis, the patient also exhibited spontaneous reattachment rhegmatogenous retinal detachment (SRRRD). Whole-exome sequencing identified a novel heterozygous variant, exon8:c.640_646del:p.R214Pfs*28. CONCLUSIONS The present study broadens the range of genetic variants described in aniridia and presents an aniridia patient with SRRRD.
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Affiliation(s)
- Qian Wang
- Beijing Tongren Eye Center, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Ophthalmology & Visual Sciences Key Lab, Medical Artificial Intelligence Research and Verification Laboratory of the Ministry of Industry and Information Technology, Beijing Tongren Hospital, Capital Medical University, China. 1 Dong Jiao Min Xiang, Dong Cheng District, Beijing, 100730, China
| | - Wen Bin Wei
- Beijing Tongren Eye Center, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Ophthalmology & Visual Sciences Key Lab, Medical Artificial Intelligence Research and Verification Laboratory of the Ministry of Industry and Information Technology, Beijing Tongren Hospital, Capital Medical University, China. 1 Dong Jiao Min Xiang, Dong Cheng District, Beijing, 100730, China
| | - Xiang Yu Shi
- Beijing Tongren Eye Center, Beijing Key Laboratory of Intraocular Tumor Diagnosis and Treatment, Beijing Ophthalmology & Visual Sciences Key Lab, Medical Artificial Intelligence Research and Verification Laboratory of the Ministry of Industry and Information Technology, Beijing Tongren Hospital, Capital Medical University, China. 1 Dong Jiao Min Xiang, Dong Cheng District, Beijing, 100730, China.
| | - Wei Ning Rong
- Ningxia Eye Hospital, People's Hospital of Ningxia Hui Autonomous Region, Third Clinical Medical College of Ningxia Medical University, Huanghe Road, Jinfeng District, the Ningxia Hui Autonomous Region, Yinchuan, 750002, China.
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Krause MA, Trout KL, Lauderdale JD, Netland PA. Visual Acuity in Aniridia and WAGR Syndrome. Clin Ophthalmol 2023; 17:1255-1261. [PMID: 37152637 PMCID: PMC10162095 DOI: 10.2147/opth.s405003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/24/2023] [Indexed: 05/09/2023] Open
Abstract
Purpose Our purpose was to evaluate visual acuity in aniridia subjects and the more severely affected phenotype in WAGR syndrome subjects, and to assess potential impact on visual function. Materials and Methods This was a retrospective comparative study of 25 aniridia subjects with nonsense mutations of PAX6 (50 eyes) and 25 WAGR syndrome subjects with large deletion mutations involving PAX6 (50 eyes). Aniridia subjects were age- and gender-matched with WAGR syndrome subjects in the Coordination of Rare Diseases at Sanford (CoRDS) database. Best-corrected ETDRS visual acuity measurements were converted to LogMAR visual acuity values, which were used to perform statistical analyses. Results The age and gender distribution of the subjects was not statistically significantly different. The mean LogMAR values in aniridia and WAGR syndrome subjects were 0.95±0.53 and 1.51±0.99, respectively (P<0.001). In the better-seeing eye, mean LogMAR values were 0.78±0.15 in aniridia subjects and 1.40±0.88 in WAGR syndrome subjects (P=0.001). The mean LogMAR values for the better-seeing eye corresponded to Snellen visual acuity of 20/125 in aniridia subjects and 20/500 in WAGR syndrome subjects. This average visual acuity was worse than the threshold for profound visual impairment (WHO criteria) and legal blindness (AAO criteria) in WAGR syndrome but not in aniridia subjects. In analysis of both eyes, the visual efficiency was 34% in aniridia subjects and 2% in WAGR syndrome subjects. Conclusion Visual acuity was significantly worse in WAGR subjects with multi-gene deletion mutations compared with aniridia subjects with nonsense mutations, which corresponded to differences in standard visual function thresholds. Our results suggest that visual acuity may indicate severity of ocular involvement and variability of phenotype in aniridia and WAGR syndrome.
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Affiliation(s)
- Michael A Krause
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Kelly L Trout
- International WAGR Syndrome Association, Montgomery Village, MD, USA
| | | | - Peter A Netland
- Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, USA
- Correspondence: Peter A Netland, Department of Ophthalmology, University of Virginia School of Medicine, 1300 Jefferson Park Avenue, P.O. Box 800715, Charlottesville, VA, 22908-0715, USA, Tel +1 434-982-1086, Email
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Ratna R, Tibrewal S, Gour A, Gupta R, Mathur U, Vanita V. A rare case of congenital aniridia with an unusual run-on mutation in PAX6 gene. Indian J Ophthalmol 2022; 70:2661-2664. [PMID: 35791194 PMCID: PMC9426074 DOI: 10.4103/ijo.ijo_433_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Affiliation(s)
- Ria Ratna
- Department of Ocular Genetics, Dr Shroff's Charity Eye Hospital, Daryaganj, New Delhi, India
| | - Shailja Tibrewal
- Department of Ocular Genetics; Department of Pediatric Ophthalmology, Strabismus and Neuro-Ophthalmology, Dr Shroff's Charity Eye Hospital, Daryaganj, New Delhi, India
| | - Abha Gour
- Department of Cornea and Anterior Segment, Dr Shroff's Charity Eye Hospital, Daryaganj, New Delhi, India
| | - Reena Gupta
- Regional Institute of Ophthalmology, Post-Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Umang Mathur
- Department of Cornea and Anterior Segment, Dr Shroff's Charity Eye Hospital, Daryaganj, New Delhi, India
| | - Vanita Vanita
- Department of Human Genetics, Guru Nanak Dev University, Amritsar, Punjab, India
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7
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de Souza VS, da Cunha GCR, Versiani BR, de Oliveira CP, Rosa MTAS, de Oliveira SF, Moretti PN, Mazzeu JF, Pic-Taylor A. Characterization of Associated Nonclassical Phenotypes in Patients with Deletion in the WAGR Region Identified by Chromosomal Microarray: New Insights and Literature Review. Mol Syndromol 2022; 13:290-304. [PMID: 36158055 PMCID: PMC9421677 DOI: 10.1159/000518872] [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: 03/16/2021] [Accepted: 08/03/2021] [Indexed: 01/03/2023] Open
Abstract
WAGR syndrome (Wilms' tumor, aniridia, genitourinary changes, and intellectual disability) is a contiguous gene deletion syndrome characterized by the joint deletion of PAX6 and WT1 genes, located in the short arm of chromosome 11. However, most deletions include other genes, leading to multiple associated phenotypes. Therefore, understanding how genes deleted together can contribute to other clinical phenotypes is still considered a challenge. In order to establish genotype-phenotype correlation in patients with interstitial deletions of the short arm of chromosome 11, we selected 17 patients with deletions identified by chromosomal microarray analysis: 4 new subjects and 13 subjects previously described in the literature with detailed clinical data. Through the analysis of deleted regions and the phenotypic changes, it was possible to suggest the contribution of specific genes to several nonclassical phenotypes, contributing to the accuracy of clinical characterization of the syndrome and emphasizing the broad phenotypic spectrum found in the patients. This study reports the first patient with a PAX6 partial deletion who does not present any eye anomaly thus opening a new set of questions about the functional activity of PAX6.
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Affiliation(s)
- Vanessa Sodré de Souza
- Programa de Pós-graduação em Biologia Animal, Universidade de Brasília, Brasília, Brazil,Programa de Pós-graduação em Ciências da Saúde, Universidade de Brasília, Brasília, Brazil
| | - Gabriela Corassa Rodrigues da Cunha
- Programa de Pós-graduação em Biologia Animal, Universidade de Brasília, Brasília, Brazil,Programa de Pós-graduação em Ciências da Saúde, Universidade de Brasília, Brasília, Brazil
| | - Beatriz R. Versiani
- Hospital de Apoio de Brasília, Secretária de Estado de Saúde do Distrito Federal, Brasília, Brazil,Hospital Universitário, Universidade de Brasília, Brasília, Brazil
| | - Claudiner Pereira de Oliveira
- Hospital de Apoio de Brasília, Secretária de Estado de Saúde do Distrito Federal, Brasília, Brazil,Hospital Universitário, Universidade de Brasília, Brasília, Brazil
| | - Maria Teresa Alves Silva Rosa
- Hospital Universitário, Universidade de Brasília, Brasília, Brazil,Programa de Pós-graduação em Ciências Médicas, Universidade de Brasília, Brasília, Brazil
| | - Silviene F. de Oliveira
- Programa de Pós-graduação em Biologia Animal, Universidade de Brasília, Brasília, Brazil,Programa de Pós-graduação em Ciências da Saúde, Universidade de Brasília, Brasília, Brazil,Departamento de Genética e Morfologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil
| | - Patricia N. Moretti
- Programa de Pós-graduação em Ciências Médicas, Universidade de Brasília, Brasília, Brazil
| | - Juliana F. Mazzeu
- Programa de Pós-graduação em Ciências da Saúde, Universidade de Brasília, Brasília, Brazil,Programa de Pós-graduação em Ciências Médicas, Universidade de Brasília, Brasília, Brazil,Faculdade de Medicina, Universidade de Brasília, Brasília, Brazil,*Juliana F. Mazzeu,
| | - Aline Pic-Taylor
- Programa de Pós-graduação em Biologia Animal, Universidade de Brasília, Brasília, Brazil,Programa de Pós-graduação em Ciências da Saúde, Universidade de Brasília, Brasília, Brazil,Programa de Pós-graduação em Ciências Médicas, Universidade de Brasília, Brasília, Brazil,Departamento de Genética e Morfologia, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, Brazil,**Aline Pic-Taylor,
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Vasilyeva TA, Marakhonov AV, Kutsev SI, Zinchenko RA. Relative Frequencies of PAX6 Mutational Events in a Russian Cohort of Aniridia Patients in Comparison with the World's Population and the Human Genome. Int J Mol Sci 2022; 23:ijms23126690. [PMID: 35743132 PMCID: PMC9223373 DOI: 10.3390/ijms23126690] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/06/2022] [Accepted: 06/13/2022] [Indexed: 12/10/2022] Open
Abstract
Genome-wide sequencing metadata allows researchers to infer bias in the relative frequencies of mutational events and to predict putative mutagenic models. In addition, much less data could be useful in the evaluation of the mutational frequency spectrum and the prevalent local mutagenic process. Here we analyzed the PAX6 gene locus for mutational spectra obtained in our own and previous studies and compared them with data on other genes as well as the whole human genome. MLPA and Sanger sequencing were used for mutation searching in a cohort of 199 index patients from Russia with aniridia and aniridia-related phenotypes. The relative frequencies of different categories of PAX6 mutations were consistent with those previously reported by other researchers. The ratio between substitutions, small indels, and chromosome deletions in the 11p13 locus was within the interval previously published for 20 disease associated genomic loci, but corresponded to a higher end due to very high frequencies of small indels and chromosome deletions. The ratio between substitutions, small indels, and chromosome deletions for disease associated genes, including the PAX6 gene as well as the share of PAX6 missense mutations, differed considerably from those typical for the whole genome.
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Affiliation(s)
- Tatyana A. Vasilyeva
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (T.A.V.); (S.I.K.); (R.A.Z.)
| | - Andrey V. Marakhonov
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (T.A.V.); (S.I.K.); (R.A.Z.)
- Correspondence: ; Tel.: +7-499-320-60-90
| | - Sergey I. Kutsev
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (T.A.V.); (S.I.K.); (R.A.Z.)
| | - Rena A. Zinchenko
- Research Centre for Medical Genetics, 115522 Moscow, Russia; (T.A.V.); (S.I.K.); (R.A.Z.)
- N.A. Semashko National Research Institute of Public Health, 105064 Moscow, Russia
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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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10
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Kit V, Cunha DL, Hagag AM, Moosajee M. Longitudinal genotype-phenotype analysis in 86 patients with PAX6-related aniridia. JCI Insight 2021; 6:e148406. [PMID: 34101622 PMCID: PMC8410060 DOI: 10.1172/jci.insight.148406] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/03/2021] [Indexed: 12/30/2022] Open
Abstract
Aniridia is most commonly caused by haploinsufficiency of the PAX6 gene, characterized by variable iris and foveal hypoplasia, nystagmus, cataracts, glaucoma, and aniridia-related keratopathy (ARK). Genotype-phenotype correlations have previously been described; however, detailed longitudinal studies of aniridia are less commonly reported. We identified 86 patients from 62 unrelated families with molecularly confirmed heterozygous PAX6 variants from a UK-based single-center ocular genetics service. They were categorized into mutation groups, and a retrospective review of clinical characteristics (ocular and systemic) from baseline to most recent was recorded. One hundred and seventy-two eyes were evaluated, with a mean follow-up period of 16.3 ± 12.7 years. Nystagmus was recorded in 87.2% of the eyes, and foveal hypoplasia was found in 75%. Cataracts were diagnosed in 70.3%, glaucoma in 20.6%, and ARK in 68.6% of eyes. Prevalence, age of diagnosis and surgical intervention, and need for surgical intervention varied among mutation groups. Overall, the missense mutation subgroup had the mildest phenotype, and surgically naive eyes maintained better visual acuity. Systemic evaluation identified type 2 diabetes in 12.8% of the study group, which is twice the UK prevalence. This is the largest longitudinal study of aniridia in the UK, and as such, it can provide insights into prognostic indicators for patients and guiding clinical management of both ocular and systemic features.
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Affiliation(s)
- Vivienne Kit
- Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom.,UCL Institute of Ophthalmology, London, United Kingdom
| | | | - Ahmed M Hagag
- Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom.,UCL Institute of Ophthalmology, London, United Kingdom
| | - Mariya Moosajee
- Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom.,UCL Institute of Ophthalmology, London, United Kingdom.,Great Ormond Street Hospital for Children, NHS Foundation Trust, London, United Kingdom.,The Francis Crick Institute, London, United Kingdom
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11
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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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12
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Grant MK, Bobilev AM, Branch A, Lauderdale JD. Structural and functional consequences of PAX6 mutations in the brain: Implications for aniridia. Brain Res 2021; 1756:147283. [PMID: 33515537 DOI: 10.1016/j.brainres.2021.147283] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 12/15/2020] [Accepted: 01/05/2021] [Indexed: 12/27/2022]
Abstract
The paired-box 6 (PAX6) gene encodes a highly conserved transcription factor essential for the proper development of the eye and brain. Heterozygous loss-of-function mutations in PAX6 are causal for a condition known as aniridia in humans and the Small eye phenotype in mice. Aniridia is characterized by iris hypoplasia and other ocular abnormalities, but recent evidence of neuroanatomical, sensory, and cognitive impairments in this population has emerged, indicating brain-related phenotypes as a prevalent feature of the disorder. Determining the neurophysiological origins of brain-related phenotypes in this disorder presents a substantial challenge, as the majority of extra-ocular traits in aniridia demonstrate a high degree of heterogeneity. Here, we summarize and integrate findings from human and rodent model studies, which have focused on neuroanatomical and functional consequences of PAX6 mutations. We highlight novel findings from PAX6 central nervous system studies in adult mammals, and integrate these findings into what we know about PAX6's role in development of the central nervous system. This review presents the current literature in the field in order to inform clinical application, discusses what is needed in future studies, and highlights PAX6 as a lens through which to understand genetic disorders affecting the human nervous system.
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Affiliation(s)
- Madison K Grant
- Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA.
| | - Anastasia M Bobilev
- Neuroscience Division of the Biomedical and Health Sciences Institute, The University of Georgia, Athens, GA 30602, USA; Department of Psychiatry, UT Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Audrey Branch
- Department of Psychological and Brain Sciences, Johns Hopkins University, Baltimore, MD 21218, USA.
| | - James D Lauderdale
- Department of Cellular Biology, The University of Georgia, Athens, GA 30602, USA; Neuroscience Division of the Biomedical and Health Sciences Institute, The University of Georgia, Athens, GA 30602, USA.
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13
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Cole JD, Rodriguez C, Norat P, Gao J, Provencio I, Netland PA, Liu X. Neural damage and neuroprotection with glaucoma development in aniridia. CURRENT NEUROBIOLOGY 2021; 12:14-19. [PMID: 38125639 PMCID: PMC10732493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Grants] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Affiliation(s)
- James D Cole
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Neuroscience Graduate Program, University of Virginia, Charlottesville, VA, USA
| | - Carlos Rodriguez
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Pedro Norat
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Jingyi Gao
- Department of Biology, University of Virginia, Charlottesville, VA, USA
| | - Ignacio Provencio
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Peter A Netland
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
| | - Xiaorong Liu
- Department of Biology, University of Virginia, Charlottesville, VA, USA
- Department of Ophthalmology, University of Virginia, Charlottesville, VA, USA
- Department of Psychology, University of Virginia, Charlottesville, VA, USA
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14
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Morphometric analysis of the lens in human aniridia and mouse Small eye. Exp Eye Res 2020; 203:108371. [PMID: 33248069 DOI: 10.1016/j.exer.2020.108371] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/17/2020] [Accepted: 11/22/2020] [Indexed: 12/16/2022]
Abstract
Congenital aniridia is caused by heterozygous mutations in the PAX6 gene. In this disease, congenital iris and foveal hypoplasia is associated with juvenile onset cataract, glaucoma, and corneal keratopathy. In rodents, Pax6 mutations result in a congenital reduction in ocular size that is not typically described in human aniridia. Here, the ocular morphometry of aniridia patients is compared with the lens phenotype of Pax6+/tm1/Pgr mice to reveal whether there are species differences in Pax6 regulation of lens development and homeostasis. Ultrasound biometry (UBM) revealed that eleven percent of aniridia patients exhibited mild microphthalmia while the anterior chamber depth of aniridic eyes was significantly reduced from 6 months of age onward. Although aniridic lens thickness was normal from birth, it was significantly decreased in aniridic lenses older than 30. Notably, 86% of aniridic lenses exhibited cataractous changes in this cohort. In addition, a significant proportion of aniridia patients develop lens subluxation as they age associated with reduced lens diameter as measured by anterior segment optical coherence tomography (AS-OCT). Analysis of young adult Pax6+/tm1/Pgr mouse lenses by micro-computed tomography (microCT), bright field and dark field imaging revealed that they are reduced in size but did not exhibit overt cataracts at this age. Overall, this study reveals that congenital microphthalmia as assessed by axial length, or microphakia, as assessed by lens thickness, are not typical in human aniridia, although these are primary manifestations of Pax6 mutations in mice, suggesting that PAX6 regulates some aspects of lens development differently between these species.
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15
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Cross E, Duncan-Flavell PJ, Howarth RJ, Crooks RO, Thomas NS, Bunyan DJ. Screening of a large PAX6 cohort identified many novel variants and emphasises the importance of the paired and homeobox domains. Eur J Med Genet 2020; 63:103940. [DOI: 10.1016/j.ejmg.2020.103940] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 12/20/2019] [Accepted: 04/23/2020] [Indexed: 12/21/2022]
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16
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Revealing hidden genetic diagnoses in the ocular anterior segment disorders. Genet Med 2020; 22:1623-1632. [PMID: 32499604 PMCID: PMC7521990 DOI: 10.1038/s41436-020-0854-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/27/2022] Open
Abstract
Purpose Ocular anterior segment disorders (ASDs) are clinically and genetically heterogeneous, and genetic diagnosis often remains elusive. In this study, we demonstrate the value of a combined analysis protocol using phenotypic, genomic, and pedigree structure data to achieve a genetic conclusion. Methods We utilized a combination of chromosome microarray, exome sequencing, and genome sequencing with structural variant and trio analysis to investigate a cohort of 41 predominantly sporadic cases. Results We identified likely causative variants in 54% (22/41) of cases, including 51% (19/37) of sporadic cases and 75% (3/4) of cases initially referred as familial ASD. Two-thirds of sporadic cases were found to have heterozygous variants, which in most cases were de novo. Approximately one-third (7/22) of genetic diagnoses were found in rarely reported or recently identified ASD genes including PXDN, GJA8, COL4A1, ITPR1, CPAMD8, as well as the new phenotypic association of Axenfeld–Rieger anomaly with a homozygous ADAMTS17 variant. The remainder of the variants were in key ASD genes including FOXC1, PITX2, CYP1B1, FOXE3, and PAX6. Conclusions We demonstrate the benefit of detailed phenotypic, genomic, variant, and segregation analysis to uncover some of the previously “hidden” heritable answers in several rarely reported and newly identified ocular ASD-related disease genes.
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17
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You B, Zhang X, Xu K, Xie Y, Ye H, Li Y. Mutation spectrum of PAX6 and clinical findings in 95 Chinese patients with aniridia. Mol Vis 2020; 26:226-234. [PMID: 32214788 PMCID: PMC7093334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Accepted: 03/24/2020] [Indexed: 11/03/2022] Open
Abstract
Purpose Aniridia is a rare congenital panocular disease caused by mutations in PAX6. The purposes of this study were to clarify the mutation features of PAX6 in a cohort of Chinese patients with aniridia and to describe their clinical characteristics. Methods We recruited 95 patients from 65 unrelated families clinically diagnosed with aniridia. All patients underwent ophthalmic examinations. Sanger sequencing and multiplex ligation probe amplification of PAX6 were performed to detect intragenic variants and copy number variations (CNVs). Results We identified 58 disease-causing mutations in PAX6 in 63 families; the detection rate was 96.9%. The 58 mutations included frameshift indels (27.6%), splice site changes (25.9%), nonsense mutations (20.7%), CNVs (19.0%), missense mutations (3.4%), run-on mutations (1.7%), and a synonymous mutation (1.7%). Clinical examinations revealed that 71 patients had complete or almost complete iris loss, 16 patients showed partial iris loss, and six patients had a full iris but with an abnormal structure. Conclusions The results confirmed that mutations in PAX6 are the predominant cause of aniridia, and the majority are loss-of-function mutations that usually result in classical aniridia. In contrast, missense mutations, run-on mutations, and small numbers of splicing mutations mostly lead to atypical aniridia and an intrafamilial phenotypic variability of iris hypoplasia.
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18
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Lagali N, Wowra B, Fries FN, Latta L, Moslemani K, Utheim TP, Wylegala E, Seitz B, Käsmann-Kellner B. Early phenotypic features of aniridia-associated keratopathy and association with PAX6 coding mutations. Ocul Surf 2020; 18:130-140. [DOI: 10.1016/j.jtos.2019.11.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2019] [Revised: 11/06/2019] [Accepted: 11/13/2019] [Indexed: 12/23/2022]
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19
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Lima Cunha D, Arno G, Corton M, Moosajee M. The Spectrum of PAX6 Mutations and Genotype-Phenotype Correlations in the Eye. Genes (Basel) 2019; 10:genes10121050. [PMID: 31861090 PMCID: PMC6947179 DOI: 10.3390/genes10121050] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 12/09/2019] [Accepted: 12/12/2019] [Indexed: 12/13/2022] Open
Abstract
The transcription factor PAX6 is essential in ocular development in vertebrates, being considered the master regulator of the eye. During eye development, it is essential for the correct patterning and formation of the multi-layered optic cup and it is involved in the developing lens and corneal epithelium. In adulthood, it is mostly expressed in cornea, iris, and lens. PAX6 is a dosage-sensitive gene and it is highly regulated by several elements located upstream, downstream, and within the gene. There are more than 500 different mutations described to affect PAX6 and its regulatory regions, the majority of which lead to PAX6 haploinsufficiency, causing several ocular and systemic abnormalities. Aniridia is an autosomal dominant disorder that is marked by the complete or partial absence of the iris, foveal hypoplasia, and nystagmus, and is caused by heterozygous PAX6 mutations. Other ocular abnormalities have also been associated with PAX6 changes, and genotype-phenotype correlations are emerging. This review will cover recent advancements in PAX6 regulation, particularly the role of several enhancers that are known to regulate PAX6 during eye development and disease. We will also present an updated overview of the mutation spectrum, where an increasing number of mutations in the non-coding regions have been reported. Novel genotype-phenotype correlations will also be discussed.
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Affiliation(s)
| | - Gavin Arno
- Institute of Ophthalmology, UCL, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
| | - Marta Corton
- Department of Genetics & Genomics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital—Universidad Autónoma de Madrid (IIS-FJD, UAM), 28040 Madrid, Spain
- Centre for Biomedical Network Research on Rare Diseases (CIBERER), 28029 Madrid, Spain
| | - Mariya Moosajee
- Institute of Ophthalmology, UCL, London EC1V 9EL, UK
- Moorfields Eye Hospital NHS Foundation Trust, London EC1V 2PD, UK
- Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, UK
- Correspondence:
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20
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Qiu JJ, Zhang Q, Geng ZX, Liu M, Zhong ZL, Chen JJ, Liu F. Identification of a novel PAX6 mutation in a Chinese family with aniridia. BMC Ophthalmol 2019; 19:10. [PMID: 30621664 PMCID: PMC6325832 DOI: 10.1186/s12886-018-1009-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 12/10/2018] [Indexed: 01/04/2023] Open
Abstract
Background This study aims to investigate the clinical characterization and causative genetic defect of a four-generation Chinese family with autosomal dominant aniridia. Methods The recruited family members underwent comprehensive routine and ophthalmic examinations, and Sanger sequencing was performed to screen the mutation in PAX6. Results A novel heterozygous PAX6 deletion c.435_445delTAGCGAAAAGC (p.Ser146ThrfsX9) in exon 7 was identified in all affected individuals, but this was absent in any of the unaffected family members and in the 200 unrelated controls. Conclusion A novel deletion in the PAX6 gene was identified in a Chinese family associated with aniridia, which expands the spectrum of the PAX6 mutation and its associated phenotype.
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Affiliation(s)
- Jing-Jing Qiu
- Department of Ophthalmology, the Second Affiliated Hospital of Nanchang University, No.1 Minde Road, Donghu District, Nanchang, 330006, China
| | - Qian Zhang
- Department of Ophthalmology, the Second Affiliated Hospital of Nanchang University, No.1 Minde Road, Donghu District, Nanchang, 330006, China.
| | - Zi-Xin Geng
- Department of Ophthalmology of Shanghai Tenth People's Hospital, and Tongji Eye Institute, Tongji University School of Medicine, Shanghai, 200092, China.,Department of Medical Genetics Tongji University School of Medicine, Shanghai, 200092, China
| | - Min Liu
- Department of Ophthalmology of Shanghai Tenth People's Hospital, and Tongji Eye Institute, Tongji University School of Medicine, Shanghai, 200092, China.,Department of Medical Genetics Tongji University School of Medicine, Shanghai, 200092, China
| | - Zi-Lin Zhong
- Department of Ophthalmology of Shanghai Tenth People's Hospital, and Tongji Eye Institute, Tongji University School of Medicine, Shanghai, 200092, China.,Department of Medical Genetics Tongji University School of Medicine, Shanghai, 200092, China
| | - Jian-Jun Chen
- Department of Ophthalmology of Shanghai Tenth People's Hospital, and Tongji Eye Institute, Tongji University School of Medicine, Shanghai, 200092, China.,Department of Medical Genetics Tongji University School of Medicine, Shanghai, 200092, China
| | - Fei Liu
- Department of Ophthalmology, the Second Affiliated Hospital of Nanchang University, No.1 Minde Road, Donghu District, Nanchang, 330006, China.
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21
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Chen DD, Yang T, Zhu SQ. Recurrent PAX 6 mutation in a Chinese family with congenital aniridia, progressive cataracts and mental retardation. Eur J Ophthalmol 2018; 30:181-188. [PMID: 30426773 DOI: 10.1177/1120672118810998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Background: One prominent pathological feature of congenital aniridia is hypoplasia of the iris, often accompanied by other eye abnormalities. The objective of this study is to identify gene mutations responsible for autosomal dominance in a Chinese family with congenital aniridia, progressive cataracts and mental retardation. Methods: A total of 11 family members, including 6 affected and 5 unaffected individuals were recruited. Whole exome sequencing was performed on the proband and Sanger sequencing was applied to identify the causal mutation in the other family members and control samples. Results: A heterozygous mutation, c. 112delC (p. Arg38fs) in PAX 6, was identified in the family that was associated with congenital aniridia, progressive cataracts and mental retardation. The mutation was exclusively observed in all affected individuals but not in unaffected family members or unrelated healthy controls without aniridia recruited from Beijing Tongren Hospital. Bioinformatics analysis indicated that the mutation c. 112delC (p. Arg38fs) in PAX 6 affected sugar phosphate backbone construction, leading to half reduction of the full-length protein. Other symptoms such as lens opacity, keratitis, lens dislocation, ciliary body hypoplasia, foveal hypoplasia and mental development retardation were also observed in this family. Conclusion: These results provided a new insight into the effects of PAX 6 as a mutational hotspot, with a symptom complex that includes congenital aniridia, progressive cataracts and mental retardation. These findings suggested the cognitive treatment of PAX 6-mutated individuals could be considered earlier clinically, combined with medication or surgery of congenital aniridia and progressive cataracts.
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Affiliation(s)
- Dou-Dou Chen
- Beijing Tongren Eye Center, Beijing Keynote Laboratory of Ophthalmology and Visual Science, Beijing Tongren Hospital, Capital Medical University, Beijing, China
| | - Tao Yang
- Department of Traditional Chinese Medicine, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
- Beijing Integrative Medicine on Encephalopathy Research Institution, Beijing, China
| | - Si-Quan Zhu
- Beijing Tongren Eye Center, Beijing Keynote Laboratory of Ophthalmology and Visual Science, Beijing Tongren Hospital, Capital Medical University, Beijing, China
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22
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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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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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Syrimis A, Nicolaou N, Alexandrou A, Papaevripidou I, Nicolaou M, Loukianou E, Sismani C, Malas S, Christophidou-Anastasiadou V, Tanteles GA. Molecular analysis of Cypriot families with aniridia reveals a novel PAX6 mutation. Mol Med Rep 2018; 18:1623-1627. [PMID: 29901133 PMCID: PMC6072148 DOI: 10.3892/mmr.2018.9126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 05/21/2018] [Indexed: 12/12/2022] Open
Abstract
The present study investigated the clinical and mutational spectrum of aniridia in a cohort of 17 affected individuals from six families from Cyprus. Each proband was initially evaluated for copy number variants at the PAX6 locus and subsequently underwent PAX6 mutation screening. Sequence analysis of FOXC1 and PITX2 was performed in patients who did not carry a PAX6 mutation. The most common clinical features in the group of aniridia patients associated with aniridia were nystagmus, cataracts and glaucoma. PAX6 pathogenic mutations were identified in five out of six families (a diagnostic yield of 84%). Previously reported pathogenic mutations in PAX6 were identified in four families, which comprise p.R203*, p.R240* and p.R317*. In addition, a novel pathogenic variant (p.E220Gfs*23) was identified in a single family. No pathogenic mutations were detected in PAX6, FOXC1 or PITX2 in the only patient with a sporadic form of aniridia‑like phenotype, confirming the genetic heterogeneity associated with this disease. To the best of our knowledge this is the first report on the mutational spectrum of PAX6 in aniridia patients of Cypriot ancestry. Mutational screening of PAX6 serves a crucial role in distinguishing isolated from syndromic forms of aniridia, and it may therefore eliminate the need for renal ultrasound scan surveillance, delineate the phenotype and improve genetic counseling.
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Affiliation(s)
- Andreas Syrimis
- Department of Clinical Genetics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
| | - Nayia Nicolaou
- Department of Clinical Genetics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
| | - Angelos Alexandrou
- Department of Cytogenetics and Genomics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
| | - Ioannis Papaevripidou
- Department of Cytogenetics and Genomics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
| | - Michael Nicolaou
- Department of Clinical Genetics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
| | - Eleni Loukianou
- Department of Ophthalmology, Nicosia General Hospital, 2029 Nicosia, Cyprus
| | - Carolina Sismani
- Department of Cytogenetics and Genomics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
| | - Stavros Malas
- Department of Developmental and Functional Genetics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
| | - Violetta Christophidou-Anastasiadou
- Department of Clinical Genetics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
- Department of Clinical Genetics, Archbishop Makarios III Hospital, 2012 Nicosia, Cyprus
| | - George A. Tanteles
- Department of Clinical Genetics, The Cyprus Institute of Neurology and Genetics, 2370 Nicosia, Cyprus
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25
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PAX6 molecular analysis and genotype-phenotype correlations in families with aniridia from Australasia and Southeast Asia. Mol Vis 2018; 24:261-273. [PMID: 29618921 PMCID: PMC5873721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 03/26/2018] [Indexed: 11/30/2022] Open
Abstract
PURPOSE Aniridia is a congenital disorder caused by variants in the PAX6 gene. In this study, we assessed the involvement of PAX6 in patients with aniridia from Australasia and Southeast Asia. METHODS Twenty-nine individuals with aniridia from 18 families originating from Australia, New Caledonia, Cambodia, Sri Lanka, and Bhutan were included. The PAX6 gene was investigated for sequence variants and analyzed for deletions with multiplex ligation-dependent probe amplification. RESULTS We identified 11 sequence variants and six chromosomal deletions, including one in mosaic. Four deleterious sequence variants were novel: p.(Pro81HisfsTer12), p.(Gln274Ter), p.(Ile29Thr), and p.(Met1?). Ocular complications were associated with a progressive loss of visual function as shown by a visual acuity ≤ 1.00 logMAR reported in 65% of eyes. The prevalence of keratopathy was statistically significantly higher in the Australasian cohort (78.6%) compared with the Southeast Asian cohort (9.1%, p=0.002). Variants resulting in protein truncating codons displayed limited genotype-phenotype correlations compared with other variants. CONCLUSIONS PAX6 variants and deletions were identified in 94% of patients with aniridia from Australasia and Southeast Asia. This study is the first report of aniridia and variations in PAX6 in individuals from Cambodia, Sri Lanka, Bhutan, and New Caledonia, and the largest cohort from Australia.
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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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Novel PAX6 mutation reported in an aniridia patient. Hum Genome Var 2017; 4:17053. [PMID: 29238604 PMCID: PMC5719187 DOI: 10.1038/hgv.2017.53] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 09/09/2017] [Accepted: 09/15/2017] [Indexed: 01/17/2023] Open
Abstract
An aniridia patient was found to have a novel PAX6 mutation. A genetic duplication within PAX6, which caused a frameshift mutation, ultimately created a nonsense stop codon and premature truncation of the protein. Consequently, the patient presented with a clouded cornea as a result of partial limbal stem cell deficiency, foveal hypoplasia, nystagmus and a pale, cupped optic disc caused by glaucoma.
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Abstract
PURPOSE OF REVIEW Aniridia is a rare and panocular disorder affecting most of the ocular structures which may have significant impact on vision. The purpose of this review is to describe the clinical features, genetics, and therapeutic options for this disease and to provide an update of current knowledge and latest research findings. RECENT FINDINGS Aside from the ocular features, a variety of associated systemic abnormalities, including hormonal, metabolic, gastrointestinal, genitourinary, and neurologic pathologies have been reported in children with aniridia. Although mutations in PAX6 are a major cause of aniridia, genetic defects in nearby genes, such as TRIM44 or ELP4, have also been reported to cause aniridia. Recent improvement in genetic testing technique will help more rapid and precise diagnosis for aniridia. A promising therapeutic approach called nonsense suppression therapy has been introduced and successfully used in an animal model. SUMMARY Aniridia is a challenging disease. The progressive nature of this condition and its potential complications require continuous and life-long ophthalmologic care. Genetic diagnosis for aniridia is important for establishing definitive molecular characterization as well as identifying individuals at high risk for Wilms tumor. Recent advancement in understanding the genetic pathogenesis of this disease offers promise for the approaches to treatment.
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29
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Miao Q, Ping X, Tang X, Zhang L, Zhang X, Cheng Y, Shentu X. Experimental assessment of novel PAX6 splicing mutations in two Chinese families with aniridia. Gene 2017; 630:44-48. [DOI: 10.1016/j.gene.2017.07.073] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 07/07/2017] [Accepted: 07/27/2017] [Indexed: 01/13/2023]
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30
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Sannan NS, Gregory-Evans CY, Lyons CJ, Lehman AM, Langlois S, Warner SJ, Zakrzewski H, Gregory-Evans K. Correlation of novel PAX6 gene abnormalities in aniridia and clinical presentation. Can J Ophthalmol 2017; 52:570-577. [PMID: 29217025 DOI: 10.1016/j.jcjo.2017.04.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 03/24/2017] [Accepted: 04/05/2017] [Indexed: 01/12/2023]
Abstract
OBJECTIVE To describe the clinical presentation and genotype of subjects with aniridia with a particular focus on foveal hypoplasia. DESIGN Prospective cohort study. PARTICIPANTS Thirty-three Canadian participants with aniridia and of various ethnic backgrounds residing in British Columbia. METHODS Full ophthalmic examinations and posterior segment spectral domain-optical coherence tomography (SD-OCT) imaging were performed. Foveal hypoplasia was graded independently by 2 staff ophthalmologists. PAX6 sequencing was performed and chromosomal 11p anomalies investigated. Candidate gene and single-nucleotide polymorphism sequencing in genes functionally related to PAX6 were also studied. RESULTS Best corrected visual acuities in the cohort ranged from 0.0 logMAR to no light perception. Total absence of iris tissue was seen in the majority (42 of 66 eyes). In those in whom SD-OCT was possible, foveal hypoplasia was seen in the majority (45 of 56 eyes, 80%). Molecular genetic defects involving PAX6 were identified in 30 participants (91%), including 4 novel PAX6 mutations (Gly18Val; Ser65ProfsX14; Met337ArgfsX18; Ser321CysfsX34) and 4 novel chromosome 11p deletions inclusive of PAX6 or a known PAX6 regulatory region. CONCLUSIONS The number of PAX6 mutations associated with aniridia continues to increase. Variable foveal architecture despite nearly identical anterior segment disease in 4 participants with an Ex9 ELP4-Ex4 DCDC1 deletion suggested that molecular cues causing variation in disease in the posterior segment differ from those at play in the anterior segment. Results in 3 patients without identifiable PAX6 mutations and a review of the literature suggest that such cases be described as phenocopies rather than actual cases of the syndrome of aniridia.
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Affiliation(s)
- Naif S Sannan
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C
| | - Cheryl Y Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C
| | - Christopher J Lyons
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C; Department of Ophthalmology, BC Children's Hospital, Vancouver, B.C
| | - Anna M Lehman
- Department of Medical Genetics, University of British Columbia, Vancouver, B.C
| | - Sylvie Langlois
- Department of Medical Genetics, University of British Columbia, Vancouver, B.C
| | - Simon J Warner
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C
| | - Helen Zakrzewski
- Cumming School of Medicine, University of Calgary, Calgary, Alta
| | - Kevin Gregory-Evans
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, B.C.
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Pérez-Solórzano S, Chacón-Camacho OF, Astiazarán MC, Ledesma-Gil G, Zenteno JC. PAX6 allelic heterogeneity in Mexican congenital aniridia patients: expanding the mutational spectrum with seven novel pathogenic variants. Clin Exp Ophthalmol 2017; 45:875-883. [PMID: 28488383 DOI: 10.1111/ceo.12982] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/24/2017] [Accepted: 05/02/2017] [Indexed: 02/04/2023]
Abstract
IMPORTANCE The importance of the study was to describe the clinical characteristics and mutational analysis of Mexican patients with aniridia. BACKGROUND Aniridia is a panocular hereditary eye disease caused by mutations in the PAX6 transcription factor. Mutation detection rate is highly variable ranging from 30% to 90% in different populations. Very few studies have been published about the PAX6 mutational analysis in aniridia patients from Mexico. In order to establish a more representative PAX6 mutational frequency in the country, a cohort of 22 Mexican unrelated aniridia probands were analysed in this study. DESIGN Case series. PARTICIPANTS A total of 22 Mexican probands with bilateral isolated aniridia and their available relatives were included. METHODS Sanger sequencing was used for the mutational analysis of all coding exons and flanking intronic regions of PAX6. MAIN OUTCOME MEASURES Clinical characteristics and results of PAX6 mutational analysis in probands with aniridia and available family members. RESULTS Molecular analysis of PAX6 in 22 index cases with aniridia allowed the identification of a total of 16 different mutations. Seven of these pathogenic variants are novel, including c.183C>G, p.(Y61*); c.718delC, p.(R240Efs*3); c.1149_1152delTCAG, p.(P385Wfs*139); c.257_266delAAATAGCCCA, p.(K86Sfs*35); c.836_843dupGCAACACA p.(P282Afs*86); c.1032+2_1032+3insT; and c.141+2T>A. Inter and intrafamilial phenotypic heterogeneity was found. CONCLUSIONS AND RELEVANCE The mutational diagnostic rate in this series was 77%, which is comparable with reports from other populations. Importantly, no founder mutations were identified in this case series. Our results add 7 novel PAX6 pathogenic variants to the aniridia-related mutational spectrum and reveal considerable PAX6 allelic heterogeneity in this population.
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Affiliation(s)
- Sofía Pérez-Solórzano
- Genetics Department, Institute of Ophthalmology 'Conde de Valenciana', Mexico City, Mexico
| | - Oscar F Chacón-Camacho
- Genetics Department, Institute of Ophthalmology 'Conde de Valenciana', Mexico City, Mexico
| | - Mirena C Astiazarán
- Genetics Department, Institute of Ophthalmology 'Conde de Valenciana', Mexico City, Mexico
| | - Gerardo Ledesma-Gil
- Retina Department, Institute of Ophthalmology 'Conde de Valenciana', Mexico City, Mexico
| | - Juan Carlos Zenteno
- Genetics Department, Institute of Ophthalmology 'Conde de Valenciana', Mexico City, Mexico.,Department of Biochemistry, Faculty of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
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Grant MK, Bobilev AM, Pierce JE, DeWitte J, Lauderdale JD. Structural brain abnormalities in 12 persons with aniridia. F1000Res 2017; 6:255. [PMID: 29034075 PMCID: PMC5615777 DOI: 10.12688/f1000research.11063.2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/27/2017] [Indexed: 02/04/2023] Open
Abstract
Background: Aniridia is a disorder predominately caused by heterozygous loss-of-function mutations of the
PAX6 gene, which is a transcriptional regulator necessary for normal eye and brain development. The ocular abnormalities of aniridia have been well characterized, but mounting evidence has implicated brain-related phenotypes as a prominent feature of this disorder as well. Investigations using neuroimaging in aniridia patients have shown reductions in discrete brain structures and changes in global grey and white matter. However, limited sample sizes and substantive heterogeneity of structural phenotypes in the brain remain a challenge.
Methods: Here, we examined brain structure in a new population sample in an effort to add to the collective understanding of anatomical abnormalities in aniridia. The current study used 3T magnetic resonance imaging to acquire high-resolution structural data in 12 persons with aniridia and 12 healthy demographically matched comparison subjects.
Results: We examined five major structures: the anterior commissure, the posterior commissure, the pineal gland, the corpus callosum, and the optic chiasm. The most consistent reductions were found in the anterior commissure and the pineal gland; however, abnormalities in all of the other structures examined were present in at least one individual.
Conclusions: Our results indicate that the anatomical abnormalities in aniridia are variable and largely individual-specific. These findings suggest that future studies investigate this heterogeneity further, and that normal population variation should be considered when evaluating structural abnormalities.
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Affiliation(s)
- Madison K Grant
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Anastasia M Bobilev
- Neuroscience Division of the Biomedical and Health Sciences Institute, University of Georgia, Athens, GA, 30602, USA
| | - Jordan E Pierce
- Department of Psychology, University of Georgia, Athens, GA, 30602, USA
| | - Jon DeWitte
- Athens Radiology Associates, Athens, GA, 30604, USA
| | - James D Lauderdale
- Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.,Neuroscience Division of the Biomedical and Health Sciences Institute, University of Georgia, Athens, GA, 30602, USA
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Hahn IK, Kim DH, Lim HT. Clinical Features and Molecular Characteristics of Korean Patients with Congenital Aniridia. JOURNAL OF THE KOREAN OPHTHALMOLOGICAL SOCIETY 2016. [DOI: 10.3341/jkos.2016.57.9.1441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- In Kyun Hahn
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
| | - Dae Hee Kim
- Department of Ophthalmology, Myongji Hospital, Seonam University College of Medicine, Goyang, Korea
| | - Hyun Taek Lim
- Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea
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