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Zucco J, Baldan F, Allegri L, Bregant E, Passon N, Franzoni A, D'Elia AV, Faletra F, Damante G, Mio C. A bird's eye view on the use of whole exome sequencing in rare congenital ophthalmic diseases. J Hum Genet 2024:10.1038/s10038-024-01237-6. [PMID: 38459225 DOI: 10.1038/s10038-024-01237-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 02/07/2024] [Accepted: 02/22/2024] [Indexed: 03/10/2024]
Abstract
Phenotypic and genotypic heterogeneity in congenital ocular diseases, especially in anterior segment dysgenesis (ASD), have created challenges for proper diagnosis and classification of diseases. Over the last decade, genomic research has indeed boosted our understanding in the molecular basis of ASD and genes associated with both autosomal dominant and recessive patterns of inheritance have been described with a wide range of expressivity. Here we describe the molecular characterization of a cohort of 162 patients displaying isolated or syndromic congenital ocular dysgenesis. Samples were analyzed with diverse techniques, such as direct sequencing, multiplex ligation-dependent probe amplification, and whole exome sequencing (WES), over 20 years. Our data reiterate the notion that PAX6 alterations are primarily associated with ASD, mostly aniridia, since the majority of the cohort (66.7%) has a pathogenic or likely pathogenic variant in the PAX6 locus. Unexpectedly, a high fraction of positive samples (20.3%) displayed deletions involving the 11p13 locus, either partially/totally involving PAX6 coding region or abolishing its critical regulatory region, underlying its significance. Most importantly, the use of WES has allowed us to both assess variants in known ASD genes (i.e., CYP1B1, ITPR1, MAB21L1, PXDN, and PITX2) and to identify rarer phenotypes (i.e., MIDAS, oculogastrointestinal-neurodevelopmental syndrome and Jacobsen syndrome). Our data clearly suggest that WES allows expanding the analytical portfolio of ocular dysgenesis, both isolated and syndromic, and that is pivotal for the differential diagnosis of those conditions in which there may be phenotypic overlaps and in general in ASD.
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Affiliation(s)
- Jessica Zucco
- Institute of Medical Genetics, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy
| | - Federica Baldan
- Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Lorenzo Allegri
- Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Elisa Bregant
- Institute of Medical Genetics, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy
| | - Nadia Passon
- Institute of Medical Genetics, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy
| | - Alessandra Franzoni
- Institute of Medical Genetics, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy
| | - Angela Valentina D'Elia
- Institute of Medical Genetics, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy
| | - Flavio Faletra
- Institute of Medical Genetics, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy.
| | - Giuseppe Damante
- Institute of Medical Genetics, Azienda Sanitaria Universitaria Friuli Centrale (ASUFC), Udine, Italy
- Department of Medicine (DMED), University of Udine, Udine, Italy
| | - Catia Mio
- Department of Medicine (DMED), University of Udine, Udine, Italy
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Basharat R, Rodenburg K, Rodríguez-Hidalgo M, Jarral A, Ullah E, Corominas J, Gilissen C, Zehra ST, Hameed U, Ansar M, de Bruijn SE. Combined Single Gene Testing and Genome Sequencing as an Effective Diagnostic Approach for Anophthalmia and Microphthalmia Patients. Genes (Basel) 2023; 14:1573. [PMID: 37628625 PMCID: PMC10454697 DOI: 10.3390/genes14081573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 07/28/2023] [Accepted: 07/29/2023] [Indexed: 08/27/2023] Open
Abstract
Anophthalmia and microphthalmia (A/M) are among the most severe congenital developmental eye disorders. Despite the advancements in genome screening technologies, more than half of A/M patients do not receive a molecular diagnosis. We included seven consanguineous families affected with A/M from Pakistani cohort and an unknown molecular basis. Single gene testing of FOXE3 was performed, followed by genome sequencing for unsolved probands in order to establish a genetic diagnosis for these families. All seven families were provided with a genetic diagnosis. The identified variants were all homozygous, classified as (likely) pathogenic and present in an A/M-associated gene. Targeted FOXE3 sequencing revealed two previously reported pathogenic FOXE3 variants in four families. In the remaining families, genome sequencing revealed a known pathogenic PXDN variant, a novel 13bp deletion in VSX2, and one novel deep intronic splice variant in PXDN. An in vitro splice assay was performed for the PXDN splice variant which revealed a severe splicing defect. Our study confirmed the utility of genome sequencing as a diagnostic tool for A/M-affected individuals. Furthermore, the identification of a novel deep intronic pathogenic variant in PXDN highlights the role of non-coding variants in A/M-disorders and the value of genome sequencing for the identification of this type of variants.
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Affiliation(s)
- Rabia Basharat
- Department of Biochemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Kim Rodenburg
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - María Rodríguez-Hidalgo
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
- Department of Neuroscience, Biodonostia Health Research Institute, 20014 Donostia-San Sebastián, Spain
| | - Afeefa Jarral
- Department of Biotechnology, Mirpur University of Science and Technology (MUST), Mirpur 10250, AJK, Pakistan
| | - Ehsan Ullah
- Department of Biochemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Jordi Corominas
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Christian Gilissen
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
| | - Syeda Tatheer Zehra
- Department of Biochemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Usman Hameed
- Department of Biochemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Muhammad Ansar
- Department of Biochemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Suzanne E. de Bruijn
- Department of Human Genetics, Radboud University Medical Center, 6500 HB Nijmegen, The Netherlands
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Vihinen M. Individual Genetic Heterogeneity. Genes (Basel) 2022; 13:genes13091626. [PMID: 36140794 PMCID: PMC9498725 DOI: 10.3390/genes13091626] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 08/25/2022] [Accepted: 09/08/2022] [Indexed: 11/28/2022] Open
Abstract
Genetic variation has been widely covered in literature, however, not from the perspective of an individual in any species. Here, a synthesis of genetic concepts and variations relevant for individual genetic constitution is provided. All the different levels of genetic information and variation are covered, ranging from whether an organism is unmixed or hybrid, has variations in genome, chromosomes, and more locally in DNA regions, to epigenetic variants or alterations in selfish genetic elements. Genetic constitution and heterogeneity of microbiota are highly relevant for health and wellbeing of an individual. Mutation rates vary widely for variation types, e.g., due to the sequence context. Genetic information guides numerous aspects in organisms. Types of inheritance, whether Mendelian or non-Mendelian, zygosity, sexual reproduction, and sex determination are covered. Functions of DNA and functional effects of variations are introduced, along with mechanism that reduce and modulate functional effects, including TARAR countermeasures and intraindividual genetic conflict. TARAR countermeasures for tolerance, avoidance, repair, attenuation, and resistance are essential for life, integrity of genetic information, and gene expression. The genetic composition, effects of variations, and their expression are considered also in diseases and personalized medicine. The text synthesizes knowledge and insight on individual genetic heterogeneity and organizes and systematizes the central concepts.
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Affiliation(s)
- Mauno Vihinen
- Department of Experimental Medical Science, BMC B13, Lund University, SE-22184 Lund, Sweden
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Chou WS, Shiao YM, Chen JS, Tsauer JC, Chang YF, Chiu YH, Hsiao CH. Novel prenatally diagnosed compound heterozygous PXDN variants in fetal congenital primary aphakia and blepharophimosis. Taiwan J Obstet Gynecol 2022; 61:510-513. [PMID: 35595447 DOI: 10.1016/j.tjog.2022.03.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2021] [Indexed: 10/18/2022] Open
Abstract
OBJECTIVE To precision survey a fetal congenital primary aphakia molecular etiology. CASE REPORT A case of 42 years old pregnancy woman prenatal diagnostic examination by amniocentesis conducted at 17 weeks' gestation and demonstrated a normal female karyotype. Trio studies based on chromosome microarray analysis (CMA) and Sanger's genetic analysis did not detect a pathologic variant of the FOXE3 gene. Fetal congenital primary aphakia accompanied with microphthalmia detected by sonography in the second trimester (22 weeks). MRI indicated bilateral absence of the lenses, consistent with primary congenital aphakia. Due to the poor prognosis of congenital aphakia, the parents decided to terminate the fetus and provided consent for an autopsy. Pathological analysis revealed dysplasia of the anterior segment of both eyes. However, post fetal mortem extended trio whole exon sequencing (WES) and Sanger's genetic analysis identified compound heterozygous variants in the chromosomal location 2p25.3 in the PXDN gene. CONCLUSION Extended whole exon sequencing is an important tool to study primary congenital aphakia.
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Affiliation(s)
- Wei Shin Chou
- Department of Obstetrics and Gynecology, Taipei City Hospital, Women and Children Campus, Taiwan
| | - Yu Ming Shiao
- Department of Bioscience Technology, Chung Yuan Christian University, Taiwan; Union Clinical Laboratory, Taiwan
| | - Jia Shing Chen
- School of Medicine for International Students, I-Shou University, Kaohsiung, Taiwan
| | - Ju Chin Tsauer
- Department of Obstetrics and Gynecology, Taipei City Hospital, Women and Children Campus, Taiwan
| | - Yi Fen Chang
- Department of Obstetrics and Gynecology, Taipei City Hospital, Women and Children Campus, Taiwan
| | | | - Ching Hua Hsiao
- Department of Obstetrics and Gynecology, Taipei City Hospital, Women and Children Campus, Taiwan; Department of Biomedical Engineering, National Yang Ming Chiao Tung University - Yang Ming Campus, Taiwan.
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