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Demler C, Lawlor JC, Yelin R, Llivichuzcha-Loja D, Shaulov L, Kim D, Stewart M, Lee F, Shylo NA, Trainor PA, Schultheiss T, Kurpios NA. An atypical basement membrane forms a midline barrier during left-right asymmetric gut development in the chicken embryo. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.08.15.553395. [PMID: 37645918 PMCID: PMC10461973 DOI: 10.1101/2023.08.15.553395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Correct intestinal morphogenesis depends on the early embryonic process of gut rotation, an evolutionarily conserved program in which a straight gut tube elongates and forms into its first loops. However, the gut tube requires guidance to loop in a reproducible manner. The dorsal mesentery (DM) connects the gut tube to the body and directs the lengthening gut into stereotypical loops via left-right (LR) asymmetric cellular and extracellular behavior. The LR asymmetry of the DM also governs blood and lymphatic vessel formation for the digestive tract, which is essential for prenatal organ development and postnatal vital functions including nutrient absorption. Although the genetic LR asymmetry of the DM has been extensively studied, a divider between the left and right DM has yet to be identified. Setting up LR asymmetry for the entire body requires a Lefty1 + midline barrier to separate the two sides of the embryo, without it, embryos have lethal or congenital LR patterning defects. Individual organs including the brain, heart, and gut also have LR asymmetry, and while the consequences of left and right signals mixing are severe or even lethal, organ-specific mechanisms for separating these signals are poorly understood. Here, we uncover a midline structure composed of a transient double basement membrane, which separates the left and right halves of the embryonic chick DM during the establishment of intestinal and vascular asymmetries. Unlike other basement membranes of the DM, the midline is resistant to disruption by intercalation of Netrin4 (Ntn4). We propose that this atypical midline forms the boundary between left and right sides and functions as a barrier necessary to establish and protect organ asymmetry.
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Lusk S, LaPotin S, Presnell JS, Kwan KM. Increased Netrin downstream of overactive Hedgehog signaling disrupts optic fissure formation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.18.599642. [PMID: 38948711 PMCID: PMC11212950 DOI: 10.1101/2024.06.18.599642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/02/2024]
Abstract
Background Uveal coloboma, a developmental eye defect, is caused by failed development of the optic fissure, a ventral structure in the optic stalk and cup where axons exit the eye and vasculature enters. The Hedgehog (Hh) signaling pathway regulates optic fissure development: loss-of-function mutations in the Hh receptor ptch2 produce overactive Hh signaling and can result in coloboma. We previously proposed a model where overactive Hh signaling disrupts optic fissure formation by upregulating transcriptional targets acting both cell- and non-cell-autonomously. Here, we examine the Netrin family of secreted ligands as candidate Hh target genes. Results We find multiple Netrin ligands upregulated in the zebrafish ptch2 mutant during optic fissure development. Using a gain-of-function approach to overexpress Netrin in a spatiotemporally specific manner, we find that netrin1a or netrin1b overexpression is sufficient to cause coloboma and disrupt wild-type optic fissure formation. We used loss-of-function alleles, CRISPR/Cas9 mutagenesis, and morpholino knockdown to test if loss of Netrin can rescue coloboma in the ptch2 mutant: loss of netrin genes does not rescue the ptch2 mutant phenotype. Conclusion These results suggest that Netrin is sufficient but not required to disrupt optic fissure formation downstream of overactive Hh signaling in the ptch2 mutant.
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Affiliation(s)
- Sarah Lusk
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112
| | - Sarah LaPotin
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112
| | - Jason S Presnell
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112
| | - Kristen M Kwan
- Department of Human Genetics, University of Utah, Salt Lake City, UT 84112
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3
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Virth J, Mack HG, Colville D, Crockett E, Savige J. Ocular manifestations of congenital anomalies of the kidney and urinary tract (CAKUT). Pediatr Nephrol 2024; 39:357-369. [PMID: 37468646 PMCID: PMC10728251 DOI: 10.1007/s00467-023-06068-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 06/15/2023] [Accepted: 06/16/2023] [Indexed: 07/21/2023]
Abstract
Congenital anomalies of the kidney and urinary tract (CAKUT) are among the most common birth defects worldwide and a major cause of kidney failure in children. Extra-renal manifestations are also common. This study reviewed diseases associated with the Genomics England CAKUT-associated gene panel for ocular anomalies. In addition, each gene was examined for expression in the human retina and an ocular phenotype in mouse models using the Human Protein Atlas and Mouse Genome Informatics databases, respectively. Thirty-four (54%) of the 63 CAKUT-associated genes (55 'green' and 8 'amber') had a reported ocular phenotype. Five of the 6 most common CAKUT-associated genes (PAX2, EYA1, SALL1, GATA3, PBX1) that represent 30% of all diagnoses had ocular features. The ocular abnormalities found with most CAKUT-associated genes and with five of the six commonest were coloboma, microphthalmia, optic disc anomalies, refraction errors (astigmatism, myopia, and hypermetropia), and cataract. Seven of the CAKUT-associated genes studied (11%) had no reported ocular features but were expressed in the human retina or had an ocular phenotype in a mouse model, which suggested further possibly-unrecognised abnormalities. About one third of CAKUT-associated genes (18, 29%) had no ocular associations and were not expressed in the retina, and the corresponding mouse models had no ocular phenotype. Ocular abnormalities in individuals with CAKUT suggest a genetic basis for the disease and sometimes indicate the affected gene. Individuals with CAKUT often have ocular abnormalities and may require an ophthalmic review, monitoring, and treatment to preserve vision.
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Affiliation(s)
- James Virth
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Heather G Mack
- University Department of Surgery (Ophthalmology), Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Deb Colville
- University Department of Surgery (Ophthalmology), Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, 3002, Australia
| | - Emma Crockett
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia
| | - Judy Savige
- Department of Medicine (Melbourne Health and Northern Health), Royal Melbourne Hospital, The University of Melbourne, Parkville, VIC, 3050, Australia.
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Casey MA, Lusk S, Kwan KM. Eye Morphogenesis in Vertebrates. Annu Rev Vis Sci 2023; 9:221-243. [PMID: 37040791 DOI: 10.1146/annurev-vision-100720-111125] [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] [Indexed: 04/13/2023]
Abstract
Proper eye structure is essential for visual function: Multiple essential eye tissues must take shape and assemble into a precise three-dimensional configuration. Accordingly, alterations to eye structure can lead to pathological conditions of visual impairment. Changes in eye shape can also be adaptive over evolutionary time. Eye structure is first established during development with the formation of the optic cup, which contains the neural retina, retinal pigment epithelium, and lens. This crucial yet deceptively simple hemispherical structure lays the foundation for all later elaborations of the eye. Building on descriptions of the embryonic eye that started with hand drawings and micrographs, the field is beginning to identify mechanisms driving dynamic changes in three-dimensional cell and tissue shape. A combination of molecular genetics, imaging, and pharmacological approaches is defining connections among transcription factors, signaling pathways, and the intracellular machinery governing the emergence of this crucial structure.
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Affiliation(s)
- Macaulie A Casey
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA; , ,
| | - Sarah Lusk
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA; , ,
| | - Kristen M Kwan
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA; , ,
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Grainger RM, Lauderdale JD, Collins JL, Trout KL, McCullen Krantz S, Wolfe SS, Netland PA. Report on the 2021 Aniridia North America symposium on PAX6, aniridia, and beyond. Ocul Surf 2023; 29:423-431. [PMID: 37247841 DOI: 10.1016/j.jtos.2023.05.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 05/31/2023]
Abstract
The inaugural Aniridia North America (ANA) Symposium was held on the first weekend in November 2021 in Charlottesville, VA, at the University of Virginia. The purpose of this meeting was to bring together an international group of scientists, physicians, patient advocacy groups, and individuals with aniridia to discuss recent advances in knowledge about aniridia and other congenital eye diseases and the development of potential treatments for congenital eye disorders using personalized medicine. Leaders in several areas of eye research and clinical treatment provided a broad perspective on new research advances that impact an understanding of the causes of the damage to the eye associated with aniridia and the development of novel treatments for this and related disorders. Here we summarize the research discussed at the symposium.
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Affiliation(s)
- Robert M Grainger
- Aniridia North America, LaGrange, IL, 60525, USA; Department of Biology, 326 Gilmer Hall University of Virginia 485 McCormick Road P.O. Box 400328 Charlottesville, VA 22904, USA.
| | - James D Lauderdale
- Aniridia North America, LaGrange, IL, 60525, USA; Department of Cellular Biology, University of Georgia, Athens, GA, 30602, USA.
| | | | | | | | | | - Peter A Netland
- Aniridia North America, LaGrange, IL, 60525, USA; Department of Ophthalmology, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
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Boobalan E, Thompson AH, Alur RP, McGaughey DM, Dong L, Shih G, Vieta-Ferrer ER, Onojafe IF, Kalaskar VK, Arno G, Lotery AJ, Guan B, Bender C, Memon O, Brinster L, Soleilhavoup C, Panman L, Badea TC, Minella A, Lopez AJ, Thomasy SM, Moshiri A, Blain D, Hufnagel RB, Cogliati T, Bharti K, Brooks BP. Zfp503/Nlz2 Is Required for RPE Differentiation and Optic Fissure Closure. Invest Ophthalmol Vis Sci 2022; 63:5. [PMID: 36326727 PMCID: PMC9645360 DOI: 10.1167/iovs.63.12.5] [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] [Indexed: 11/06/2022] Open
Abstract
Purpose Uveal coloboma is a congenital eye malformation caused by failure of the optic fissure to close in early human development. Despite significant progress in identifying genes whose regulation is important for executing this closure, mutations are detected in a minority of cases using known gene panels, implying additional genetic complexity. We have previously shown knockdown of znf503 (the ortholog of mouse Zfp503) in zebrafish causes coloboma. Here we characterize Zfp503 knockout (KO) mice and evaluate transcriptomic profiling of mutant versus wild-type (WT) retinal pigment epithelium (RPE)/choroid. Methods Zfp503 KO mice were generated by gene targeting using homologous recombination. Embryos were characterized grossly and histologically. Patterns and level of developmentally relevant proteins/genes were examined with immunostaining/in situ hybridization. The transcriptomic profile of E11.5 KO RPE/choroid was compared to that of WT. Results Zfp503 is dynamically expressed in developing mouse eyes, and loss of its expression results in uveal coloboma. KO embryos exhibit altered mRNA levels and expression patterns of several key transcription factors involved in eye development, including Otx2, Mitf, Pax6, Pax2, Vax1, and Vax2, resulting in a failure to maintain the presumptive RPE, as evidenced by reduced melanin pigmentation and its differentiation into a neural retina-like lineage. Comparison of RNA sequencing data from WT and KO E11.5 embryos demonstrated reduced expression of melanin-related genes and significant overlap with genes known to be dynamically regulated at the optic fissure. Conclusions These results demonstrate a critical role of Zfp503 in maintaining RPE fate and optic fissure closure.
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Affiliation(s)
- Elangovan Boobalan
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Amy H. Thompson
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Ramakrishna P. Alur
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - David M. McGaughey
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Lijin Dong
- Mouse Genetic Engineering Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Grace Shih
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Emile R. Vieta-Ferrer
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Ighovie F. Onojafe
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Vijay K. Kalaskar
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Gavin Arno
- University College London Institute of Ophthalmology, London, United Kingdom,Moorfields Eye Hospital, London, United Kingdom
| | - Andrew J. Lotery
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Bin Guan
- Ophthalmic Genetics Laboratory, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Chelsea Bender
- Ophthalmic Genetics Laboratory, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Omar Memon
- Ocular and Stem Cell Translational Research Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Lauren Brinster
- Division of Veterinary Resources, Office of Research Services, National Institutes of Health, Bethesda, Maryland, United States
| | | | - Lia Panman
- MRC Toxicology Unit, University of Cambridge, Leicester, United Kingdom
| | - Tudor C. Badea
- Retinal Circuit Development and Genetics Unit, Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States,Research and Development Institute, Transilvania University of Brașov, Brașov, Romania,National Center for Brain Research, ICIA, Romanian Academy, Bucharest, România
| | - Andrea Minella
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California–Davis, Davis, California, United States
| | - Antonio Jacobo Lopez
- Department of Ophthalmology and Vision Science, School of Medicine, University of California–Davis, Davis, California, United States
| | - Sara M. Thomasy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California–Davis, Davis, California, United States,Department of Ophthalmology and Vision Science, School of Medicine, University of California–Davis, Davis, California, United States
| | - Ala Moshiri
- Department of Ophthalmology and Vision Science, School of Medicine, University of California–Davis, Davis, California, United States
| | - Delphine Blain
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Robert B. Hufnagel
- Ophthalmic Genetics Laboratory, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Tiziana Cogliati
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Kapil Bharti
- Ocular and Stem Cell Translational Research Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Brian P. Brooks
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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Diacou R, Nandigrami P, Fiser A, Liu W, Ashery-Padan R, Cvekl A. Cell fate decisions, transcription factors and signaling during early retinal development. Prog Retin Eye Res 2022; 91:101093. [PMID: 35817658 PMCID: PMC9669153 DOI: 10.1016/j.preteyeres.2022.101093] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 12/30/2022]
Abstract
The development of the vertebrate eyes is a complex process starting from anterior-posterior and dorso-ventral patterning of the anterior neural tube, resulting in the formation of the eye field. Symmetrical separation of the eye field at the anterior neural plate is followed by two symmetrical evaginations to generate a pair of optic vesicles. Next, reciprocal invagination of the optic vesicles with surface ectoderm-derived lens placodes generates double-layered optic cups. The inner and outer layers of the optic cups develop into the neural retina and retinal pigment epithelium (RPE), respectively. In vitro produced retinal tissues, called retinal organoids, are formed from human pluripotent stem cells, mimicking major steps of retinal differentiation in vivo. This review article summarizes recent progress in our understanding of early eye development, focusing on the formation the eye field, optic vesicles, and early optic cups. Recent single-cell transcriptomic studies are integrated with classical in vivo genetic and functional studies to uncover a range of cellular mechanisms underlying early eye development. The functions of signal transduction pathways and lineage-specific DNA-binding transcription factors are dissected to explain cell-specific regulatory mechanisms underlying cell fate determination during early eye development. The functions of homeodomain (HD) transcription factors Otx2, Pax6, Lhx2, Six3 and Six6, which are required for early eye development, are discussed in detail. Comprehensive understanding of the mechanisms of early eye development provides insight into the molecular and cellular basis of developmental ocular anomalies, such as optic cup coloboma. Lastly, modeling human development and inherited retinal diseases using stem cell-derived retinal organoids generates opportunities to discover novel therapies for retinal diseases.
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Affiliation(s)
- Raven Diacou
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Prithviraj Nandigrami
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Andras Fiser
- Department of Systems and Computational Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Wei Liu
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Ruth Ashery-Padan
- Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel
| | - Ales Cvekl
- Department of Genetics, Albert Einstein College of Medicine, Bronx, NY, 10461, USA; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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8
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Ouyang J, Li S, Sun W, Xiao X, Wang Y, Jiang Y, Zhang Q. Variants in HNRNPH1 are associated with high myopia in humans and ocular coloboma in zebrafish. Clin Genet 2022; 102:424-433. [PMID: 35989590 DOI: 10.1111/cge.14213] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 07/22/2022] [Accepted: 08/14/2022] [Indexed: 11/29/2022]
Abstract
High myopia is one of the most common causes for blindness due to its associated complications. Genetic factor has been considered as the major cause for early-onset high myopia (eoHM), but exact genetic defects for most eoHM are yet to be identified. Through multi-step bioinformatics analysis of our in-house whole exome sequencing dataset from 5310 individuals, variants from 653 probands with eoHM were further compared with those from in-house controls as well as gnomAD database. The results showed that loss-of-function (LoF) variants in a novel gene HNRNPH1 were identified in two of 653 probands with eoHM but in none of 4657 probands with other eye conditions (P = 0.015). LoF variants in HNRNPH1 were extremely rare and intolerant, while two LoF variants in 653 eoHM were statistically higher than their frequency in gnomAD (P = 1.09×10-3 ). These two LoF variants, c.2dupT/p.? and c.121dup/p.(Q41Pfs*20), were absent from existing database. Variants in HNRNPH1 have not been associated with any inherited eye disease before. Expression of HNRNPH1 was enriched in ganglion cell layer and inner nuclear layer in humans. Knockdown of hnrnph1 in zebrafish resulted in ocular coloboma. All these suggests that HNRNPH1 supports its potential contribution to eoHM when mutated.
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Affiliation(s)
- Jiamin Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yingwei Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Yi Jiang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangzhou, China
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Khan TA, Liaqat T, Shahid M, Janjua TA, Rauf A. Isolated Chorioretinal Coloboma: A Case Report. Cureus 2022; 14:e28048. [PMID: 36127994 PMCID: PMC9477557 DOI: 10.7759/cureus.28048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/15/2022] [Indexed: 11/29/2022] Open
Abstract
Ocular coloboma is a rare congenital anomaly that arises due to an abnormality in embryogenesis. It occurs due to failed fusion of the embryonic fissure resulting in a persistent defect. Colobomas may present with vision loss but are most commonly asymptomatic and diagnosed incidentally. In this article, we present a case of asymptomatic chorioretinal coloboma diagnosed on routine screening. The patient was managed with prophylactic argon laser retinopexy to prevent complications leading to visual impairment in the future.
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10
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Donabedian PL, Walia JY, Agarwal-Sinha S. Partial CHARGE syndrome with bilateral retinochoroidal colobomas associated with 7q11.23 duplication syndrome: case report. BMC Ophthalmol 2022; 22:100. [PMID: 35246073 PMCID: PMC8895878 DOI: 10.1186/s12886-022-02298-x] [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: 05/25/2021] [Accepted: 02/03/2022] [Indexed: 11/10/2022] Open
Abstract
Background CHARGE syndrome is a relatively common cause of deafness and blindness resulting from failure to form the primordia of specific organs due to deficient contribution of neural crest cell derivatives. The majority of CHARGE syndrome cases are caused by heterozygous mutations in CHD7 on chromosome 8q21. Those with CHARGE syndrome without CHD7 mutation typically do not have an identified genetic defect. 7q11.23 duplication syndrome is associated with mild facial dysmorphism, heart defects, language delay, and autism spectrum disorder. In the current literature, 7q11.23 duplication has not been associated with CHARGE syndrome, retinochoroidal colobomas, or significant ear abnormalities. Case presentation We describe a patient with 7q11.23 duplication syndrome and clinical CHARGE syndrome with no variant in CHARGE-associated genes. Conclusions This case highlights the still incomplete understanding of the pathogenesis of CHARGE syndrome and raises the possibility of a dose-sensitive effect of genes in the 7q11.23 critical region on neural crest differentiation and fate.
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Affiliation(s)
- Patrick L Donabedian
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Jessica Y Walia
- Department of Ophthalmology, University of Florida College of Medicine, Gainesville, FL, USA
| | - Swati Agarwal-Sinha
- Department of Ophthalmology, Seattle Children's Hospital, University of Washington, Seattle, WA, USA.
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Fox SC, Widen SA, Asai-Coakwell M, Havrylov S, Benson M, Prichard LB, Baddam P, Graf D, Lehmann OJ, Waskiewicz AJ. BMP3 is a novel locus involved in the causality of ocular coloboma. Hum Genet 2022; 141:1385-1407. [PMID: 35089417 DOI: 10.1007/s00439-022-02430-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/04/2022] [Indexed: 12/29/2022]
Abstract
Coloboma, a congenital disorder characterized by gaps in ocular tissues, is caused when the choroid fissure fails to close during embryonic development. Several loci have been associated with coloboma, but these represent less than 40% of those that are involved with this disease. Here, we describe a novel coloboma-causing locus, BMP3. Whole exome sequencing and Sanger sequencing of patients with coloboma identified three variants in BMP3, two of which are predicted to be disease causing. Consistent with this, bmp3 mutant zebrafish have aberrant fissure closure. bmp3 is expressed in the ventral head mesenchyme and regulates phosphorylated Smad3 in a population of cells adjacent to the choroid fissure. Furthermore, mutations in bmp3 sensitize embryos to Smad3 inhibitor treatment resulting in open choroid fissures. Micro CT scans and Alcian blue staining of zebrafish demonstrate that mutations in bmp3 cause midface hypoplasia, suggesting that bmp3 regulates cranial neural crest cells. Consistent with this, we see active Smad3 in a population of periocular neural crest cells, and bmp3 mutant zebrafish have reduced neural crest cells in the choroid fissure. Taken together, these data suggest that Bmp3 controls Smad3 phosphorylation in neural crest cells to regulate early craniofacial and ocular development.
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Affiliation(s)
- Sabrina C Fox
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Sonya A Widen
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada.,Vienna BioCenter, Institute of Molecular Biotechnology of the Austrian Academy of Sciences (IMBA), Vienna, Austria.,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada
| | - Mika Asai-Coakwell
- Department of Animal and Poultry and Animal Science, University of Saskatchewan, Saskatoon, SK, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Serhiy Havrylov
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Matthew Benson
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Lisa B Prichard
- Department of Biological Sciences, MacEwan University, Edmonton, AB, Canada
| | - Pranidhi Baddam
- Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Daniel Graf
- Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Ordan J Lehmann
- Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, AB, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, AB, Canada
| | - Andrew J Waskiewicz
- Department of Biological Sciences, University of Alberta, 11455 Saskatchewan Drive, Edmonton, AB, T6G 2E9, Canada. .,Women and Children's Health Research Institute, University of Alberta, Edmonton, AB, Canada.
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12
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Selzer EB, Blain D, Hufnagel RB, Lupo PJ, Mitchell LE, Brooks BP. Review of Evidence for Environmental Causes of Uveal Coloboma. Surv Ophthalmol 2021; 67:1031-1047. [PMID: 34979194 DOI: 10.1016/j.survophthal.2021.12.008] [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: 04/19/2021] [Revised: 12/22/2021] [Accepted: 12/27/2021] [Indexed: 10/19/2022]
Abstract
Uveal coloboma is a condition defined by missing ocular tissues and is a significant cause of childhood blindness. It occurs from a failure of the optic fissure to close during embryonic development,and may lead to missing parts of the iris, ciliary body, retina, choroid, and optic nerve. Because there is no treatment for coloboma, efforts have focused on prevention. While several genetic causes of coloboma have been identified, little definitive research exists regarding the environmental causes of this condition. We review the current literature on environmental factors associated with coloboma in an effort to guide future research and preventative counseling related to this condition.
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Affiliation(s)
- Evan B Selzer
- Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Delphine Blain
- Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Robert B Hufnagel
- Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD
| | - Philip J Lupo
- Department of Pediatrics, Section of Hematology-Oncology, Baylor College of Medicine, Houston, TX
| | - Laura E Mitchell
- Department of Epidemiology, Human Genetics and Environmental Sciences, UTHealth School of Public Health, Houston, TX
| | - Brian P Brooks
- Ophthalmic Genetics & Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, MD.
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13
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Shankar SP, Fallurin R, Watson T, Shankar PR, Young TL, Orel-Bixler D, Rauen KA. Ophthalmic manifestations in Costello syndrome caused by Ras pathway dysregulation during development. Ophthalmic Genet 2021; 43:48-57. [PMID: 34612139 DOI: 10.1080/13816810.2021.1978103] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
BACKGROUND Costello syndrome (CS) is a multisystem developmental disorder caused by germline pathogenic variants in HRAS resulting in dysregulation of the Ras pathway. A systematic characterization of ophthalmic manifestations provides a unique opportunity to understand the role of Ras signal transduction in ocular development and guide optimal ophthalmic care in CS individuals. METHODS Visual function, ocular features and genotype/phenotype correlations were evaluated in CS individuals harboring HRAS pathogenic variants, by cross-sectional and retrospective studies, and were recruited through the Costello Syndrome Family Network (CSFN) between 2007 and 2020. RESULTS Fifty-six molecularly diagnosed CS individuals including 34 females and 22 males, ages ranging from 0.5 to 37 years were enrolled. The most common ophthalmic manifestations in the cross-sectional study were lack of stereopsis (96%), refractive errors (83%), strabismus (72%), nystagmus (69%), optic nerve hypoplasia or pallor (55%) and ptosis (13.7%) with higher prevalence than in the retrospective data (refractive errors (41%), strabismus (44%), nystagmus (26%), optic nerve hypoplasia or pallor (7%) and ptosis (11%)). Visual acuities were found to ranged from 20/25 to 20/800 and contrast sensitivity from 1.6% to 44%. HRAS pathogenic variants included p.G12S (84%), p.G13C (7%), p.G12A (5.4%), p.G12C (1.8%) and p.A146V (1.8%). CONCLUSION Majority of individuals with CS have refractive errors, strabismus, nystagmus, absent stereopsis, and optic nerve abnormalities suggesting that HRAS and the Ras pathway play a vital role in visual system development. Ptosis, refractive errors and strabismus are amenable to treatment and early ophthalmic evaluation is crucial to prevent long-term vision impairment and improve overall quality of life in CS.
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Affiliation(s)
- Suma P Shankar
- Department of Pediatrics, University of California Davis, Sacramento, California, USA.,Department of Ophthalmology, University of California Davis, Sacramento, California, USA
| | - Reshmitha Fallurin
- Department of Internal Medicine, The Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| | - Tonya Watson
- The School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, USA
| | - Prabhu R Shankar
- Department of Public Health, University of California Davis, Sacramento, California, USA
| | - Terri L Young
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, USA
| | - Deborah Orel-Bixler
- The School of Optometry and Vision Science, University of California Berkeley, Berkeley, California, USA
| | - Katherine A Rauen
- Department of Pediatrics, University of California Davis, Sacramento, California, USA
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14
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Lusk S, Kwan KM. Pax2a, but not pax2b, influences cell survival and periocular mesenchyme localization to facilitate zebrafish optic fissure closure. Dev Dyn 2021; 251:625-644. [PMID: 34535934 PMCID: PMC8930785 DOI: 10.1002/dvdy.422] [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: 07/01/2021] [Revised: 08/23/2021] [Accepted: 09/13/2021] [Indexed: 11/09/2022] Open
Abstract
Background Pax2 is required for optic fissure development in many organisms, including humans and zebrafish. Zebrafish loss‐of‐function mutations in pax2a display coloboma, yet the etiology of the morphogenetic defects is unclear. Further, pax2 is duplicated in zebrafish, and a role for pax2b in optic fissure development has not been examined. Results Using a combination of imaging and molecular genetics, we interrogated a potential role for pax2b and examined how loss of pax2 affects optic fissure development. Although optic fissure formation appears normal in pax2 mutants, an endothelial‐specific subset of periocular mesenchyme (POM) fails to initially localize within the optic fissure, yet both neural crest and endothelial‐derived POM ectopically accumulate at later stages in pax2a and pax2a; pax2b mutants. Apoptosis is not up‐regulated within the optic fissure in pax2 mutants, yet cell death is increased in tissues outside of the optic fissure, and when apoptosis is inhibited, coloboma is partially rescued. In contrast to pax2a, loss of pax2b does not appear to affect optic fissure morphogenesis. Conclusions Our results suggest that pax2a, but not pax2b, supports cell survival outside of the optic fissure and POM abundance within it to facilitate optic fissure closure. Zebrafish pax2a null mutants display a defect in optic fissure closure and coloboma Loss of pax2b does not affect optic fissure development An endothelial‐specific subset of periocular mesenchyme cells fails to initially localize to the optic fissure in pax2a mutants At a later stage of optic fissure development both neural crest and endothelial‐derived periocular mesenchyme ectopically accumulate within the optic fissure Pax2a mutants have increased apoptosis in surrounding tissues, but not within the optic fissure margin cells, and apoptosis in part underlies the coloboma phenotype
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Affiliation(s)
- Sarah Lusk
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA
| | - Kristen M Kwan
- Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA
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15
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Chen HY, Lehmann OJ, Swaroop A. Genetics and therapy for pediatric eye diseases. EBioMedicine 2021; 67:103360. [PMID: 33975254 PMCID: PMC8122153 DOI: 10.1016/j.ebiom.2021.103360] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/29/2021] [Accepted: 04/12/2021] [Indexed: 12/26/2022] Open
Abstract
Ocular morphogenesis in vertebrates is a highly organized process, orchestrated largely by intrinsic genetic programs that exhibit stringent spatiotemporal control. Alternations in these genetic instructions can lead to hereditary or nonhereditary congenital disorders, a major cause of childhood visual impairment, and contribute to common late-onset blinding diseases. Currently, limited treatment options exist for clinical phenotypes involving eye development. This review summarizes recent advances in our understanding of early-onset ocular disorders and highlights genetic complexities in development and diseases, specifically focusing on coloboma, congenital glaucoma and Leber congenital amaurosis. We also discuss innovative paradigms for potential therapeutic modalities.
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Affiliation(s)
- Holly Y Chen
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892 USA.
| | - Ordan J Lehmann
- Department of Ophthalmology and Visual Sciences, University of Alberta, Edmonton, Canada; Department of Medical Genetics, University of Alberta, Edmonton, Canada.
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, National Institutes of Health, MSC0610, 6 Center Drive, Bethesda, MD 20892 USA.
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16
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Rootman MS, Dotan G, Konen O. Neuroimaging in Children with Ophthalmological Complaints: A Review. J Neuroimaging 2021; 31:446-458. [PMID: 33615595 DOI: 10.1111/jon.12842] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Revised: 01/22/2021] [Accepted: 01/23/2021] [Indexed: 11/27/2022] Open
Abstract
Pediatric patients are commonly referred to imaging following abnormal ophthalmological examinations. Common indications include papilledema, altered vision, strabismus, nystagmus, anisocoria, proptosis, coloboma, and leukocoria. Magnetic resonance imaging (MRI) of the brain and orbits (with or without contrast material administration) is typically the imaging modality of choice. However, a cranial CT scan is sometimes initially performed, particularly when MRI is not readily available. Familiarity with the various ophthalmological conditions may assist the radiologist in formulating differential diagnoses and proper MRI protocols afterward. Although MRI of the brain and orbits usually suffices, further refinements are sometimes warranted to enable suitable assessment and accurate diagnosis. For example, the assessment of children with sudden onset anisocoria associated with Horner syndrome will require imaging of the entire oculosympathetic pathway, including the brain, orbits, neck, and chest. Dedicated orbital scans should cover the area between the hard palate and approximately 1 cm above the orbits in the axial plane and extend from the lens to the midpons in the coronal plane. Fat-suppressed T2-weighted fast spin echo sequences should enable proper assessment of the globes, optic nerves, and perioptic subarachnoid spaces. Contrast material should be given judiciously, ideally according to clinical circumstances and precontrast scans. In this review, we discuss the major indications for imaging following abnormal ophthalmological examinations.
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Affiliation(s)
- Mika Shapira Rootman
- Department of Radiology, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University
| | - Gad Dotan
- Ophthalmology Unit, Schneider Children's Medical center of Israel, Petac Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University
| | - Osnat Konen
- Department of Radiology, Schneider Children's Medical Center of Israel, Petah Tikva, Israel.,Sackler Faculty of Medicine, Tel-Aviv University
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17
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Chan BHC, Moosajee M, Rainger J. Closing the Gap: Mechanisms of Epithelial Fusion During Optic Fissure Closure. Front Cell Dev Biol 2021; 8:620774. [PMID: 33505973 PMCID: PMC7829581 DOI: 10.3389/fcell.2020.620774] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 12/08/2020] [Indexed: 12/13/2022] Open
Abstract
A key embryonic process that occurs early in ocular development is optic fissure closure (OFC). This fusion process closes the ventral optic fissure and completes the circumferential continuity of the 3-dimensional eye. It is defined by the coming together and fusion of opposing neuroepithelia along the entire proximal-distal axis of the ventral optic cup, involving future neural retina, retinal pigment epithelium (RPE), optic nerve, ciliary body, and iris. Once these have occurred, cells within the fused seam differentiate into components of the functioning visual system. Correct development and progression of OFC, and the continued integrity of the fused margin along this axis, are important for the overall structure of the eye. Failure of OFC results in ocular coloboma-a significant cause of childhood visual impairment that can be associated with several complex ocular phenotypes including microphthalmia and anterior segment dysgenesis. Despite a large number of genes identified, the exact pathways that definitively mediate fusion have not yet been found, reflecting both the biological complexity and genetic heterogeneity of the process. This review will highlight how recent developmental studies have become focused specifically on the epithelial fusion aspects of OFC, applying a range of model organisms (spanning fish, avian, and mammalian species) and utilizing emerging high-resolution live-imaging technologies, transgenic fluorescent models, and unbiased transcriptomic analyses of segmentally-dissected fissure tissue. Key aspects of the fusion process are discussed, including basement membrane dynamics, unique cell behaviors, and the identities and fates of the cells that mediate fusion. These will be set in the context of what is now known, and how these point the way to new avenues of research.
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Affiliation(s)
- Brian Ho Ching Chan
- The Division of Functional Genetics and Development, The Royal Dick School of Veterinary Sciences, The Roslin Institute, The University of Edinburgh, Scotland, United Kingdom
| | - Mariya Moosajee
- University College London Institute of Ophthalmology, London, United Kingdom.,The Francis Crick Institute, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom.,Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
| | - Joe Rainger
- The Division of Functional Genetics and Development, The Royal Dick School of Veterinary Sciences, The Roslin Institute, The University of Edinburgh, Scotland, United Kingdom
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18
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Multiple roles for Pax2 in the embryonic mouse eye. Dev Biol 2021; 472:18-29. [PMID: 33428890 DOI: 10.1016/j.ydbio.2020.12.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 12/23/2020] [Accepted: 12/24/2020] [Indexed: 02/07/2023]
Abstract
The vertebrate eye anlage grows out of the brain and folds into bilayered optic cups. The eye is patterned along multiple axes, precisely controlled by genetic programs, to delineate neural retina, pigment epithelium, and optic stalk tissues. Pax genes encode developmental regulators of key morphogenetic events, with Pax2 being essential for interpreting inductive signals, including in the eye. PAX2 mutations cause ocular coloboma, when the ventral optic fissure fails to close. Previous studies established that Pax2 is necessary for fissure closure and to maintain the neural retina -- glial optic stalk boundary. Using a Pax2GFP/+ knock-in allele we discovered that the mutant optic nerve head (ONH) lacks molecular boundaries with the retina and RPE, rendering the ONH larger than normal. This was preceded by ventronasal cup mispatterning, a burst of overproliferation and followed by optic cup apoptosis. Our findings support the hypothesis that ONH cells are tripotential, requiring Pax2 to remain committed to glial fates. This work extends current models of ocular development, contributes to broader understanding of tissue boundary formation and informs the underlying mechanisms of human coloboma.
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19
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Haug P, Koller S, Maggi J, Lang E, Feil S, Wlodarczyk A, Bähr L, Steindl K, Rohrbach M, Gerth-Kahlert C, Berger W. Whole Exome Sequencing in Coloboma/Microphthalmia: Identification of Novel and Recurrent Variants in Seven Genes. Genes (Basel) 2021; 12:65. [PMID: 33418956 PMCID: PMC7825129 DOI: 10.3390/genes12010065] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/25/2020] [Accepted: 12/31/2020] [Indexed: 12/16/2022] Open
Abstract
Coloboma and microphthalmia (C/M) are related congenital eye malformations, which can cause significant visual impairment. Molecular diagnosis is challenging as the genes associated to date with C/M account for only a small percentage of cases. Overall, the genetic cause remains unknown in up to 80% of patients. High throughput DNA sequencing technologies, including whole-exome sequencing (WES), are therefore a useful and efficient tool for genetic screening and identification of new mutations and novel genes in C/M. In this study, we analyzed the DNA of 19 patients with C/M from 15 unrelated families using singleton WES and data analysis for 307 genes of interest. We identified seven novel and one recurrent potentially disease-causing variants in CRIM1, CHD7, FAT1, PTCH1, PUF60, BRPF1, and TGFB2 in 47% of our families, three of which occurred de novo. The detection rate in patients with ocular and extraocular manifestations (67%) was higher than in patients with an isolated ocular phenotype (46%). Our study highlights the significant genetic heterogeneity in C/M cohorts and emphasizes the diagnostic power of WES for the screening of patients and families with C/M.
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Affiliation(s)
- Patricia Haug
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Samuel Koller
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Jordi Maggi
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Elena Lang
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
- Department of Ophthalmology, University Hospital and University of Zurich, 8091 Zurich, Switzerland;
| | - Silke Feil
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Agnès Wlodarczyk
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Luzy Bähr
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
| | - Katharina Steindl
- Institute of Medical Genetics, University of Zurich, 8952 Schlieren, Switzerland;
| | - Marianne Rohrbach
- Division of Metabolism and Children’s Research Centre, University Children’s Hospital Zurich, 8032 Zurich, Switzerland;
| | - Christina Gerth-Kahlert
- Department of Ophthalmology, University Hospital and University of Zurich, 8091 Zurich, Switzerland;
| | - Wolfgang Berger
- Institute of Medical Molecular Genetics, University of Zurich, 8952 Schlieren, Switzerland; (P.H.); (S.K.); (J.M.); (E.L.); (S.F.); (A.W.); (L.B.)
- Neuroscience Center Zurich (ZNZ), University and ETH Zurich, 8006 Zurich, Switzerland
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, 8006 Zurich, Switzerland
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20
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Sakaguchi Y, Yoshihashi H, Uehara T, Miyama S, Kosaki K, Takenouchi T. Coloboma may be a shared feature in a spectrum of disorders caused by mutations in the WDR37-PACS1-PACS2 axis. Am J Med Genet A 2020; 185:884-888. [PMID: 33369122 DOI: 10.1002/ajmg.a.62020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 01/12/2023]
Abstract
We report a male adult with early infantile-onset epilepsy, facial dysmorphism, and iridal and choroidal coloboma who had a de novo heterozygous mutation in PACS2, that is, c.625G > A p.(Glu209Lys). This specific mutation was previously reported in a patient with PACS2-related disorder (early infantile epileptic encephalopathy 66). De novo heterozygous mutations in WDR37 have been shown to cause a novel human disorder, neurooculocardiogenitourinary syndrome (NOCGUS syndrome) (OMIM #618652), characterized by intellectual disability, facial dysmorphism, and coloboma. According to large-scale interactome data, WDR37 interacts most strongly, by far, with PACS1 and PACS2. Clinically, coloboma has been described as a feature in a WDR37-related disorder and a PACS1-related disorder (Schuurs-Hoeijmakers syndrome), but not in a PACS2-related disorder. Our review of the phenotypes of three human disorders caused by WDR37, PACS1, and PACS2 mutations showed a significant overlap of epilepsy, intellectual disability, cerebellar atrophy, and facial features. The present observation of coloboma as a shared feature among these three disorders suggests that this group of genes may be involved in ocular development. We propose that dysregulation of the WDR37-PACS1-PACS2 axis results in a spectrum that is recognizable by intellectual disability, distinctive facial features, and coloboma.
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Affiliation(s)
- Yuri Sakaguchi
- Division of Neurology, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Hiroshi Yoshihashi
- Division of Clinical Genetics, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Tomoko Uehara
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Sahoko Miyama
- Division of Neurology, Tokyo Metropolitan Children's Medical Center, Tokyo, Japan
| | - Kenjiro Kosaki
- Center for Medical Genetics, Keio University School of Medicine, Tokyo, Japan
| | - Toshiki Takenouchi
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
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21
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Sun WR, Ramirez S, Spiller KE, Zhao Y, Fuhrmann S. Nf2 fine-tunes proliferation and tissue alignment during closure of the optic fissure in the embryonic mouse eye. Hum Mol Genet 2020; 29:3373-3387. [PMID: 33075808 DOI: 10.1093/hmg/ddaa228] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/29/2020] [Accepted: 10/12/2020] [Indexed: 11/14/2022] Open
Abstract
Uveal coloboma represents one of the most common congenital ocular malformations accounting for up to 10% of childhood blindness (~1 in 5000 live birth). Coloboma originates from defective fusion of the optic fissure (OF), a transient gap that forms during eye morphogenesis by asymmetric, ventral invagination. Genetic heterogeneity combined with the activity of developmentally regulated genes suggests multiple mechanisms regulating OF closure. The tumor suppressor and FERM domain protein Neurofibromin 2 (NF2) controls diverse processes in cancer, development and regeneration, via Hippo pathway and cytoskeleton regulation. In humans, NF2 mutations can cause ocular abnormalities, including coloboma, however, its actual role in OF closure is unknown. Using conditional inactivation in the embryonic mouse eye, our data indicate that loss of Nf2 function results in a novel underlying cause for coloboma. In particular, mutant eyes show substantially increased retinal pigmented epithelium (RPE) proliferation in the fissure region with concomitant acquisition of RPE cell fate. Cells lining the OF margin can maintain RPE fate ectopically and fail to transition from neuroepithelial to cuboidal shape. In the dorsal RPE of the optic cup, Nf2 inactivation leads to a robust increase in cell number, with local disorganization of the cytoskeleton components F-actin and pMLC2. We propose that RPE hyperproliferation is the primary cause for the observed defects causing insufficient alignment of the OF margins in Nf2 mutants and failure to fuse properly, resulting in persistent coloboma. Our findings indicate that limiting proliferation particularly in the RPE layer is a critical mechanism during OF closure.
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Affiliation(s)
- Wesley R Sun
- Department of Ophthalmology and Visual Sciences, VEI, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sara Ramirez
- Department of Ophthalmology and Visual Sciences, VEI, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
| | - Kelly E Spiller
- Department of Ophthalmology and Visual Sciences, VEI, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Yan Zhao
- Department of Ophthalmology and Visual Sciences, VEI, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Sabine Fuhrmann
- Department of Ophthalmology and Visual Sciences, VEI, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37240, USA
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22
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Hernández-Medrano C, Hidalgo-Bravo A, Villanueva-Mendoza C, Bautista-Tirado T, Apam-Garduño D. Mosaic cat eye syndrome in a child with unilateral iris coloboma. Ophthalmic Genet 2020; 42:84-87. [PMID: 33465332 DOI: 10.1080/13816810.2020.1839918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Cat eye syndrome (CES) is a rare chromosomal disorder with a known incidence of 1 per 50,000-150,000 live newborns. The classic triad of iris coloboma, anorectal malformations, and auricular abnormalities is present in 40% of patients. In addition, other ocular malformations and systemic defects can be present. The aim of this report is to present a patient with unilateral iris coloboma related to a mosaicism of cat eye syndrome. METHODS A complete ophthalmological and systemic evaluation was performed in a three-year-old male. He also underwent a standard karyotype and FISH analysis with a probe against the 22q11.2 locus. RESULTS The ophthalmological and systemic evaluation revealed a unilateral iris coloboma and ipsilateral auricular malformations. Karyotype analysis of blood leukocytes indicated the presence of a marker chromosome in 6% of the analyzed cells. FISH analysis showed three positive signals in 5.5% of the analyzed nucleus. CONCLUSION This patient presented two of the three classic manifestations of CES; interestingly, they were unilateral. The 22q11 duplication was identified by standard karyotype and confirmed with FISH. The present case demonstrates the importance of conducting a multidisciplinary approach in patients with congenital malformations associated with known syndromes.
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Affiliation(s)
| | | | | | | | - David Apam-Garduño
- Genetics Department, Asociación Para Evitar la Ceguera en México , Mexico City, Mexico
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23
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Yoon KH, Fox SC, Dicipulo R, Lehmann OJ, Waskiewicz AJ. Ocular coloboma: Genetic variants reveal a dynamic model of eye development. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:590-610. [PMID: 32852110 DOI: 10.1002/ajmg.c.31831] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 12/21/2022]
Abstract
Ocular coloboma is a congenital disorder of the eye where a gap exists in the inferior retina, lens, iris, or optic nerve tissue. With a prevalence of 2-19 per 100,000 live births, coloboma, and microphthalmia, an associated ocular disorder, represent up to 10% of childhood blindness. It manifests due to the failure of choroid fissure closure during eye development, and it is a part of a spectrum of ocular disorders that include microphthalmia and anophthalmia. Use of genetic approaches from classical pedigree analyses to next generation sequencing has identified more than 40 loci that are associated with the causality of ocular coloboma. As we have expanded studies to include singleton cases, hereditability has been very challenging to prove. As such, researchers over the past 20 years, have unraveled the complex interrelationship amongst these 40 genes using vertebrate model organisms. Such research has greatly increased our understanding of eye development. These genes function to regulate initial specification of the eye field, migration of retinal precursors, patterning of the retina, neural crest cell biology, and activity of head mesoderm. This review will discuss the discovery of loci using patient data, their investigations in animal models, and the recent advances stemming from animal models that shed new light in patient diagnosis.
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Affiliation(s)
- Kevin H Yoon
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Sabrina C Fox
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Renée Dicipulo
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
| | - Ordan J Lehmann
- Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada.,Department of Medical Genetics, University of Alberta, Edmonton, Alberta, Canada.,Department of Ophthalmology, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew J Waskiewicz
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta, Canada.,Women & Children's Health Research Institute, University of Alberta, Edmonton, Canada
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24
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Eintracht J, Toms M, Moosajee M. The Use of Induced Pluripotent Stem Cells as a Model for Developmental Eye Disorders. Front Cell Neurosci 2020; 14:265. [PMID: 32973457 PMCID: PMC7468397 DOI: 10.3389/fncel.2020.00265] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/28/2020] [Indexed: 12/15/2022] Open
Abstract
Approximately one-third of childhood blindness is attributed to developmental eye disorders, of which 80% have a genetic cause. Eye morphogenesis is tightly regulated by a highly conserved network of transcription factors when disrupted by genetic mutations can result in severe ocular malformation. Human-induced pluripotent stem cells (hiPSCs) are an attractive tool to study early eye development as they are more physiologically relevant than animal models, can be patient-specific and their use does not elicit the ethical concerns associated with human embryonic stem cells. The generation of self-organizing hiPSC-derived optic cups is a major advancement to understanding mechanisms of ocular development and disease. Their development in vitro has been found to mirror that of the human eye and these early organoids have been used to effectively model microphthalmia caused by a VSX2 variant. hiPSC-derived optic cups, retina, and cornea organoids are powerful tools for future modeling of disease phenotypes and will enable a greater understanding of the pathophysiology of many other developmental eye disorders. These models will also provide an effective platform for identifying molecular therapeutic targets and for future clinical applications.
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Affiliation(s)
| | - Maria Toms
- UCL Institute of Ophthalmology, London, United Kingdom.,The Francis Crick Institute, London, United Kingdom
| | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, United Kingdom.,The Francis Crick Institute, London, United Kingdom.,Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom.,Great Ormond Street Hospital for Children NHS Foundation Trust, London, United Kingdom
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25
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Valencia-Peña C, Jiménez-Sanchez P, Saldarriaga W, Payán-Gómez C. Optic nerve coloboma as extension of the phenotype of 22q11.23 duplication syndrome: a case report. BMC Ophthalmol 2020; 20:333. [PMID: 32807111 PMCID: PMC7433184 DOI: 10.1186/s12886-020-01603-w] [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: 02/24/2020] [Accepted: 08/06/2020] [Indexed: 05/30/2023] Open
Abstract
BACKGROUND 22q11.2 duplication syndrome (Dup22q11.2) has reduced penetrance and variable expressivity. Those affected may have intellectual disabilities, dysmorphic facial features, and ocular alterations such as ptosis, hypertelorism, nystagmus, and chorioretinal coloboma. The prevalence of this syndrome is unknown, there are only approximately 100 cases reported. However Dup22q11.2 should have a similar prevalence of DiGeorge syndrome (1 in each 4000 new-borns), in which the same chromosomal region that is duplicated in Dup22q11.2 is deleted. CASE PRESENTATION We report a patient with intellectual disability, psychomotor development delay, hearing loss with disyllable pronunciation only, hyperactivity, self-harm, hetero-aggressive behaviour, facial dysmorphism, left facial paralysis, post-axial polydactyly, and for the first time in patients with Dup22q11.2, optic nerve coloboma and dysplasia in optic nerve. Array comparative genomic hybridization showed a 22q11.23 duplication of 1.306 million base pairs. CONCLUSIONS New ocular findings in Dup22q11.2 syndrome, such as coloboma and dysplasia in the optic nerve, are reported here, contributing to the phenotypic characterization of a rarely diagnosed genetic syndrome. A complete characterization of the phenotype is necessary to increase the rate of clinical suspicion and then the genetic diagnostic. In addition, through bioinformatics analysis of the genes mapped to the 22q11.2 region, it is proposed that deregulation of the SPECC1L gene could be implicated in the development of ocular coloboma.
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Affiliation(s)
- Claudia Valencia-Peña
- Department of Ophthalmology, Faculty of Health, Universidad del Valle, Cali, Colombia
| | | | - Wilmar Saldarriaga
- Departments of Morphology and Gynaecology and Obstetrics, Universidad del Valle, Cali, Colombia.,Obstetrician Gynaecologist at Hospital Universitario del Valle, Cali, Colombia
| | - César Payán-Gómez
- Department of Biology, Faculty of Natural Sciences, Universidad del Rosario, Bogotá, Colombia.
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26
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Aubert-Mucca M, Pernin-Grandjean J, Marchasson S, Gaston V, Habib C, Meunier I, Sigaudy S, Kaplan J, Roche O, Denis D, Bitoun P, Haye D, Verloes A, Calvas P, Chassaing N, Plaisancié J. Confirmation of FZD5 implication in a cohort of 50 patients with ocular coloboma. Eur J Hum Genet 2020; 29:131-140. [PMID: 32737437 DOI: 10.1038/s41431-020-0695-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 07/01/2020] [Accepted: 07/07/2020] [Indexed: 11/09/2022] Open
Abstract
Defects in optic fissure closure can lead to congenital ocular coloboma. This ocular malformation, often associated with microphthalmia, is described in various clinical forms with different inheritance patterns and genetic heterogeneity. In recent times, the identification of an increased number of genes involved in numerous cellular functions has led to a better understanding in optic fissure closure mechanisms. Nevertheless, most of these genes are also involved in wider eye growth defects such as micro-anophthalmia, questioning the mechanisms controlling both extension and severity of optic fissure closure defects. However, some genes, such as FZD5, have only been so far identified in isolated coloboma. Thus, to estimate the frequency of implication of different ocular genes, we screened a cohort of 50 patients affected by ocular coloboma by using targeted sequencing of 119 genes involved in ocular development. This analysis revealed seven heterozygous (likely) pathogenic variants in RARB, MAB21L2, RBP4, TFAP2A, and FZD5. Surprisingly, three out of the seven variants detected herein were novel disease-causing variants in FZD5 identified in three unrelated families with dominant inheritance. Although molecular diagnosis rate remains relatively low in patients with ocular coloboma (14% (7/50) in this work), these results, however, highlight the importance of genetic screening, especially of FZD5, in such patients. Indeed, in our series, FZD5 variants represent half of the genetic causes, constituting 6% (3/50) of the patients who benefited from a molecular diagnosis. Our findings support the involvement of FZD5 in ocular coloboma and provide clues for screening this gene during current diagnostic procedures.
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Affiliation(s)
- Marion Aubert-Mucca
- Service de Génétique Médicale, Hôpital Purpan, CHU Toulouse, Toulouse, France
| | | | | | - Veronique Gaston
- Service de Génétique Médicale, Hôpital Purpan, CHU Toulouse, Toulouse, France
| | - Christophe Habib
- Service de Génétique Médicale, Hôpital Purpan, CHU Toulouse, Toulouse, France
| | - Isabelle Meunier
- Centre de Référence des Maladies Sensorielles Génétiques, Hôpital Gui de Chauliac, Institut de Neurosciences de Montpellier, INSERM U1051, Université de Montpellier, Montpellier, France
| | - Sabine Sigaudy
- Département de Génétique Médicale, AP-HM, CHU Timone Enfants, Marseille, France
| | - Josseline Kaplan
- Laboratoire de Génétique Ophtalmologique, INSERM U1163 Institut Imagine, Paris, France
| | - Olivier Roche
- Département d'Ophtalmologie, IHU Necker-Enfants-Malades, Université Paris-Descartes, Paris, France
| | - Danièle Denis
- Institut de Neurosciences de la Timone (INT), Centre National de la Recherche Scientifique (CNRS), Aix-Marseille Université (AMU), Marseille, France
| | - Pierre Bitoun
- Département d'Ophtalmologie, SIDVA 91, Juvisy-sur-Orge, France
| | - Damien Haye
- Département de Génétique, Hôpital Robert Debré, Paris, France
| | - Alain Verloes
- Département de Génétique, Hôpital Robert Debré, Paris, France
| | - Patrick Calvas
- Service de Génétique Médicale, Hôpital Purpan, CHU Toulouse, Toulouse, France.,INSERM U1056, UDEAR, Equipe 4, Université Toulouse III, Toulouse, France.,Centre de Référence des Affections Rares en Génétique Ophtalmologique CARGO, Site Constitutif, CHU Toulouse, Toulouse, France
| | - Nicolas Chassaing
- Service de Génétique Médicale, Hôpital Purpan, CHU Toulouse, Toulouse, France.,INSERM U1056, UDEAR, Equipe 4, Université Toulouse III, Toulouse, France.,Centre de Référence des Affections Rares en Génétique Ophtalmologique CARGO, Site Constitutif, CHU Toulouse, Toulouse, France
| | - Julie Plaisancié
- Service de Génétique Médicale, Hôpital Purpan, CHU Toulouse, Toulouse, France. .,INSERM U1056, UDEAR, Equipe 4, Université Toulouse III, Toulouse, France. .,Centre de Référence des Affections Rares en Génétique Ophtalmologique CARGO, Site Constitutif, CHU Toulouse, Toulouse, France.
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27
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Sinagoga KL, Larimer-Picciani AM, George SM, Spencer SA, Lister JA, Gross JM. Mitf-family transcription factor function is required within cranial neural crest cells to promote choroid fissure closure. Development 2020; 147:dev187047. [PMID: 32541011 PMCID: PMC7375471 DOI: 10.1242/dev.187047] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 05/29/2020] [Indexed: 12/13/2022]
Abstract
A crucial step in eye development is the closure of the choroid fissure (CF), a transient structure in the ventral optic cup through which vasculature enters the eye and ganglion cell axons exit. Although many factors have been identified that function during CF closure, the molecular and cellular mechanisms mediating this process remain poorly understood. Failure of CF closure results in colobomas. Recently, MITF was shown to be mutated in a subset of individuals with colobomas, but how MITF functions during CF closure is unknown. To address this issue, zebrafish with mutations in mitfa and tfec, two members of the Mitf family of transcription factors, were analyzed and their functions during CF closure determined. mitfa;tfec mutants possess severe colobomas and our data demonstrate that Mitf activity is required within cranial neural crest cells (cNCCs) during CF closure. In the absence of Mitf function, cNCC migration and localization in the optic cup are perturbed. These data shed light on the cellular mechanisms underlying colobomas in individuals with MITF mutations and identify a novel role for Mitf function in cNCCs during CF closure.
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Affiliation(s)
- Katie L Sinagoga
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Alessandra M Larimer-Picciani
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Stephanie M George
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Samantha A Spencer
- Department of Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - James A Lister
- Department of Human and Molecular Genetics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, USA
| | - Jeffrey M Gross
- Departments of Ophthalmology and Developmental Biology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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28
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Eckert P, Knickmeyer MD, Heermann S. In Vivo Analysis of Optic Fissure Fusion in Zebrafish: Pioneer Cells, Basal Lamina, Hyaloid Vessels, and How Fissure Fusion is Affected by BMP. Int J Mol Sci 2020; 21:ijms21082760. [PMID: 32316164 PMCID: PMC7215994 DOI: 10.3390/ijms21082760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 04/02/2020] [Accepted: 04/09/2020] [Indexed: 02/07/2023] Open
Abstract
Colobomata, persistent optic fissures, frequently cause congenital blindness. Here, we focused on optic fissure fusion using in vivo time-lapse imaging in zebrafish. We identified the fusion initiating cells, which we termed “pioneer cells.” Based on morphology, localization, and downregulation of the neuroretinal (NR) precursor marker rx2, these cells could be considered as retinal pigment epithelial (RPE) progenitors. Notably, pioneer cells regain rx2 expression and integrate into the NR after fusion, indicating that they do not belong to the pool of RPE progenitors, supported by the lack of RPE marker expression in pioneer cells. They establish the first cellular contact between the margins in the proximal fissure region and separate the hyaloid artery and vein. After initiation, the fusion site is progressing distally, increasing the distance between the hyaloid artery and vein. A timed BMP (Bone Morphogenetic Protein) induction, resulting in coloboma, did not alter the morphology of the fissure margins, but it did affect the expression of NR and RPE markers within the margins. In addition, it resulted in a persisting basal lamina and persisting remnants of periocular mesenchyme and hyaloid vasculature within the fissure, supporting the necessity of BMP antagonism within the fissure margins. The hampered fissure fusion had severe effects on the vasculature of the eye.
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Affiliation(s)
- Priska Eckert
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany; (P.E.); (M.D.K.)
- Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, D-79104 Freiburg, Germany
| | - Max D. Knickmeyer
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany; (P.E.); (M.D.K.)
- Faculty of Biology, University of Freiburg, Schaenzlestrasse 1, D-79104 Freiburg, Germany
| | - Stephan Heermann
- Department of Molecular Embryology, Institute of Anatomy and Cell Biology, Faculty of Medicine, University Freiburg, 79104 Freiburg, Germany; (P.E.); (M.D.K.)
- Correspondence:
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29
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Two Cases of Oculofaciocardiodental (OFCD) Syndrome due to X-Linked BCOR Mutations Presenting with Infantile Hemangiomas: Phenotypic Overlap with PHACE Syndrome. Case Rep Genet 2020; 2019:9382640. [PMID: 31956451 PMCID: PMC6949664 DOI: 10.1155/2019/9382640] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Accepted: 12/07/2019] [Indexed: 01/16/2023] Open
Abstract
Background Oculofaciocardiodental (OFCD) syndrome is due to mutations in BCOR (BCL-6 corepressor). OFCD has phenotypic overlaps with PHACE syndrome (Posterior fossa anomalies, Hemangioma, Arterial anomalies, Cardiac defects, Eye anomalies). Infantile hemangiomas are a key diagnostic criterion for PHACE, but not for OFCD. A previous study reported two cases of infantile hemangiomas in OFCD, but the authors could not exclude chance association. Case Presentation We describe two novel cases of female patients (one initially diagnosed with PHACE syndrome), both of whom had infantile hemangiomas. Ophthalmological findings were consistent with oculofaciocardiodental (OFCD) syndrome. Upon genetic testing, these two females were determined to have X-linked BCOR mutations confirming OFCD syndrome diagnoses. Conclusion These case reports add support to the hypothesis that infantile hemangiomas may be a feature of OFCD. BCOR may potentially be within a pathway of genes involved in PHACE syndrome and/or in infantile hemangioma formation.
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30
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Kalaskar VK, Alur RP, Li LK, Thomas JW, Sergeev YV, Blain D, Hufnagel RB, Cogliati T, Brooks BP. High-throughput custom capture sequencing identifies novel mutations in coloboma-associated genes: Mutation in DNA-binding domain of retinoic acid receptor beta affects nuclear localization causing ocular coloboma. Hum Mutat 2019; 41:678-695. [PMID: 31816153 PMCID: PMC7027867 DOI: 10.1002/humu.23954] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Revised: 10/04/2019] [Accepted: 11/09/2019] [Indexed: 12/11/2022]
Abstract
Uveal coloboma is a potentially blinding congenital ocular malformation caused by the failure of optic fissure closure during the fifth week of human gestation. We performed custom capture high‐throughput screening of 38 known coloboma‐associated genes in 66 families. Suspected causative novel variants were identified in TFAP2A and CHD7, as well as two previously reported variants of uncertain significance in RARB and BMP7. The variant in RARB, unlike previously reported disease mutations in the ligand‐binding domain, was a missense change in the highly conserved DNA‐binding domain predicted to affect the protein's DNA‐binding ability. In vitro studies revealed lower steady‐state protein levels, reduced transcriptional activity, and incomplete nuclear localization of the mutant RARB protein compared with wild‐type. Zebrafish studies showed that human RARB messenger RNA partially reduced the ocular phenotype caused by morpholino knockdown of rarga gene, a zebrafish homolog of human RARB. Our study indicates that sequence alterations in known coloboma genes account for a small percentage of coloboma cases and that mutations in the RARB DNA‐binding domain could result in human disease.
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Affiliation(s)
- Vijay K Kalaskar
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics and Visual Function Branch (OGVFB), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, Maryland
| | - Ramakrishna P Alur
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics and Visual Function Branch (OGVFB), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, Maryland
| | - LeeAnn K Li
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics and Visual Function Branch (OGVFB), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, Maryland
| | - James W Thomas
- National Institutes of Health Intramural Sequencing Center, National Human Genome Research Institute, NIH, Bethesda, Maryland
| | - Yuri V Sergeev
- Protein Biochemistry and Molecular Modeling Group, OGVFB, NEI, NIH, Bethesda, Maryland
| | - Delphine Blain
- Ophthalmic Clinical Genetics Section, OGVFB, NEI, NIH, Bethesda, Maryland
| | - Robert B Hufnagel
- Medical Genetics and Ophthalmic Genomics Unit, OGVFB, NEI, NIH, Bethesda, Maryland
| | - Tiziana Cogliati
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics and Visual Function Branch (OGVFB), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, Maryland
| | - Brian P Brooks
- Pediatric, Developmental & Genetic Ophthalmology Section, Ophthalmic Genetics and Visual Function Branch (OGVFB), National Eye Institute (NEI), National Institutes of Health (NIH), Bethesda, Maryland.,Ophthalmic Clinical Genetics Section, OGVFB, NEI, NIH, Bethesda, Maryland
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31
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Calvas P, Traboulsi EI, Ragge N. Through the looking glass: eye anomalies in the age of molecular science. Hum Genet 2019; 138:795-798. [PMID: 31392423 DOI: 10.1007/s00439-019-02056-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 08/01/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Patrick Calvas
- INSERM U1056, Centre de Référence des Anomalies Rares en Génétique Ophtalmologique, Service de Génétique Médicale, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, Toulouse, France
| | - Elias I Traboulsi
- Center for Genetic Eye Diseases/i32, Cole Eye Institute, The Cleveland Clinic, 9500 Euclid Ave, Cleveland, OH, 44195, USA
| | - Nicola Ragge
- Faculty of Health and Life Sciences, Oxford Brookes University, Oxford, OX3 0BP, UK. .,West Midlands Regional Clinical Genetics Service and Birmingham Health Partners, Birmingham Women's and Children's NHS Foundation Trust, Birmingham, B15 2TG, UK.
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