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Wormser O, Perez Y, Dolgin V, Kamali B, Tangeman JA, Gradstein L, Yogev Y, Hadar N, Freund O, Drabkin M, Halperin D, Irron I, Grajales-Esquivel E, Del Rio-Tsonis K, Birnbaum RY, Akler G, Birk OS. IHH enhancer variant within neighboring NHEJ1 intron causes microphthalmia anophthalmia and coloboma. NPJ Genom Med 2023; 8:22. [PMID: 37580330 PMCID: PMC10425348 DOI: 10.1038/s41525-023-00364-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 07/27/2023] [Indexed: 08/16/2023] Open
Abstract
Genomic sequences residing within introns of few genes have been shown to act as enhancers affecting expression of neighboring genes. We studied an autosomal recessive phenotypic continuum of microphthalmia, anophthalmia and ocular coloboma, with no apparent coding-region disease-causing mutation. Homozygosity mapping of several affected Jewish Iranian families, combined with whole genome sequence analysis, identified a 0.5 Mb disease-associated chromosome 2q35 locus (maximal LOD score 6.8) harboring an intronic founder variant in NHEJ1, not predicted to affect NHEJ1. The human NHEJ1 intronic variant lies within a known specifically limb-development enhancer of a neighboring gene, Indian hedgehog (Ihh), known to be involved in eye development in mice and chickens. Through mouse and chicken molecular development studies, we demonstrated that this variant is within an Ihh enhancer that drives gene expression in the developing eye and that the identified variant affects this eye-specific enhancer activity. We thus delineate an Ihh enhancer active in mammalian eye development whose variant causes human microphthalmia, anophthalmia and ocular coloboma. The findings highlight disease causation by an intronic variant affecting the expression of a neighboring gene, delineating molecular pathways of eye development.
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Affiliation(s)
- Ohad Wormser
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yonatan Perez
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Vadim Dolgin
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Bahman Kamali
- Medical Advisory Committee, United Mashhadi Jewish Community of America, 54 Steamboat Rd., Great Neck, NY, 11024, USA
| | - Jared A Tangeman
- Department of Biology and Center for Visual Sciences, Miami University, Oxford, OH, 45056, USA
| | - Libe Gradstein
- Department of Ophthalmology, Soroka Medical Center and Clalit Health Services, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Yuval Yogev
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Noam Hadar
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Ofek Freund
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Max Drabkin
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Daniel Halperin
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Inbar Irron
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Erika Grajales-Esquivel
- Department of Biology and Center for Visual Sciences, Miami University, Oxford, OH, 45056, USA
| | - Katia Del Rio-Tsonis
- Department of Biology and Center for Visual Sciences, Miami University, Oxford, OH, 45056, USA
| | - Ramon Y Birnbaum
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Gidon Akler
- TOVANA Health, Houston, TX, USA.
- Precision Medicine Insights, P.C., Great Neck, NY, USA.
| | - Ohad S Birk
- The Morris Kahn Laboratory of Human Genetics, National Institute for Biotechnology in the Negev and Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
- Genetics Institute, Soroka Medical Center affiliated to Ben-Gurion University of the Negev, Beer-Sheva, Israel.
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2
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Piryaei F, Pakmanesh R, Salehirad M, Akbari S, Edizadeh M, Khodadadi H. ALDH1A3-related congenital microphthalmia-8 due to a novel frameshift variant. Eur J Med Genet 2023:104801. [PMID: 37339696 DOI: 10.1016/j.ejmg.2023.104801] [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: 09/01/2022] [Revised: 04/10/2023] [Accepted: 06/12/2023] [Indexed: 06/22/2023]
Abstract
Microphthalmia (MCOP) is a group of rare developmental malformations of eye with often reduced size of the eyeball, leading to blindness. Affecting about 1 in 7000 live births, MCOP can occur due to either environmental or genetic factors. Isolated microphthalmia-8 (MCOP8) has been proved to be caused by autosomal recessive mutations of the ALDH1A3 gene (MIM*600463) encoding aldehyde dehydrogenase 1 family, member A3. Herein, we report an 8-year-old boy with vision problems since birth from a first-cousin consanguineous parents. The main symptoms of the patient included severe bilateral microphthalmia, cyst in the left eye and blindness. The child developed behavioral disorders at the age of 7. It should be noted that there is no family history of the disease. To identify the genetic factor underlying the pathogenesis in this case Whole Exome Sequencing (WES) was performed and followed by Sanger sequencing. A novel pathogenic variant, c.1441delA (p.M482Cfs*8), in the ALDH1A3 gene was detected by WES in the proband. Further prenatal diagnosis is highly suggested to the family for the future pregnancies.
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Affiliation(s)
- Fahimeh Piryaei
- Department of Molecular Medicine and Genetics, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Rezvan Pakmanesh
- Department of Biotechnology, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Lorestan, Iran; MADAR Genetics Laboratory, Khorramabad, Lorestan, Iran
| | - Maryam Salehirad
- Department of Biotechnology, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Lorestan, Iran; MADAR Genetics Laboratory, Khorramabad, Lorestan, Iran
| | - Soheila Akbari
- Department of Obstetrics and Gynecology, School of Medicine, Lorestan University of Medical Sciences, Khorramabad, Lorestan, Iran
| | - Masoud Edizadeh
- Department of Biotechnology, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Lorestan, Iran; MADAR Genetics Laboratory, Khorramabad, Lorestan, Iran
| | - Hamidreza Khodadadi
- Department of Biotechnology, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Lorestan, Iran; Hepatitis Research Center, Department of Biotechnology, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Lorestan, Iran.
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3
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Cardozo MJ, Sánchez-Bustamante E, Bovolenta P. Optic cup morphogenesis across species and related inborn human eye defects. Development 2023; 150:dev200399. [PMID: 36714981 PMCID: PMC10110496 DOI: 10.1242/dev.200399] [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: 01/31/2023]
Abstract
The vertebrate eye is shaped as a cup, a conformation that optimizes vision and is acquired early in development through a process known as optic cup morphogenesis. Imaging living, transparent teleost embryos and mammalian stem cell-derived organoids has provided insights into the rearrangements that eye progenitors undergo to adopt such a shape. Molecular and pharmacological interference with these rearrangements has further identified the underlying molecular machineries and the physical forces involved in this morphogenetic process. In this Review, we summarize the resulting scenarios and proposed models that include common and species-specific events. We further discuss how these studies and those in environmentally adapted blind species may shed light on human inborn eye malformations that result from failures in optic cup morphogenesis, including microphthalmia, anophthalmia and coloboma.
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Affiliation(s)
- Marcos J. Cardozo
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
| | - Elena Sánchez-Bustamante
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
| | - Paola Bovolenta
- Centro de Biología Molecular Severo Ochoa, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), c/ Nicolás Cabrera 1, Cantoblanco, Madrid 28049, Spain
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4
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Smirnov VM, Robert MP, Condroyer C, Navarro J, Antonio A, Rozet JM, Sahel JA, Perrault I, Audo I, Zeitz C. Association of Missense Variants in VSX2 With a Peculiar Form of Congenital Stationary Night Blindness Affecting All Bipolar Cells. JAMA Ophthalmol 2022; 140:1163-1173. [PMID: 36264558 PMCID: PMC9585472 DOI: 10.1001/jamaophthalmol.2022.4146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 08/23/2022] [Indexed: 01/12/2023]
Abstract
Importance Congenital stationary night blindness (CSNB) is an inherited stationary retinal disorder that is clinically and genetically heterogeneous. To date, the genetic association between some cases with CSNB and an unusual complex clinical picture is unclear. Objective To describe an unreported CSNB phenotype and the associated gene defect in 3 patients from 2 unrelated families. Design, Setting, and Participants This retrospective case series was conducted in 2021 and 2022 at a national referral center for rare ocular diseases. Data for 3 patients from a cohort of 140 genetically unsolved CSNB cases were analyzed clinically and genetically. Exposures Complete ocular examination including full-field electroretinography and multimodal fundus imaging (spectral-domain optical coherence tomography, color, infrared reflectance, and short-wavelength autofluorescence photographs) were performed. The gene defect was identified by exome sequencing and confirmed by Sanger sequencing and co-segregation analysis in 1 family. Screening was performed for genetically unsolved CSNB cases for VSX2 variants by direct Sanger sequencing. Main Outcomes and Measures Ocular and molecular biology findings. Results The series included 3 patients whose clinical investigations occurred at ages in the early 30s, younger than 12 years, and in the mid 40s. They had nystagmus, low stable visual acuity, and myopia from birth and experienced night blindness. Two older patients had bilateral lens luxation and underwent lens extraction. Full-field electroretinography revealed an electronegative Schubert-Bornschein appearance, combining characteristics of incomplete and complete CSNB, affecting the function of rod and cone ON- and OFF-bipolar cells. Exome sequencing and co-segregation analysis in a consanguineous family with 2 affected members identified a homozygous variant in VSX2. Subsequently, screening of the CSNB cohort identified another unrelated patient harboring a distinct VSX2 variant. Conclusions and Relevance This case series revealed a peculiar pan-bipolar cell retinopathy with lens luxation associated with variants in VSX2. Clinicians should be aware of this association and VSX2 added to CSNB diagnostic gene panels.
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Affiliation(s)
- Vasily M. Smirnov
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Université de Lille, Faculté de Médecine, Lille, France
- Exploration de la Vision et Neuro-Ophtalmologie, CHU de Lille, Lille, France
| | - Matthieu P. Robert
- Ophthalmology Department, Hôpital Universitaire Necker-Enfants Malades, Paris, France
- Borelli Centre, UMR 9010, CNRS-SSA-ENS Paris Saclay-Paris University, Gif-sur-Yvette, France
| | | | - Julien Navarro
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Aline Antonio
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
| | - Jean-Michel Rozet
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Isabelle Perrault
- Laboratory of Genetics in Ophthalmology (LGO), INSERM UMR 1163, Institute of Genetic Diseases, Imagine Institute, and Paris University, Paris, France
| | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, Centre de Référence Maladies Rares REFERET and INSERM-DGOS CIC 1423, Paris, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, Paris, France
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5
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Bian F, Daghsni M, Lu F, Liu S, Gross JM, Aldiri I. Functional analysis of the Vsx2 super-enhancer uncovers distinct cis-regulatory circuits controlling Vsx2 expression during retinogenesis. Development 2022; 149:dev200642. [PMID: 35831950 PMCID: PMC9440754 DOI: 10.1242/dev.200642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Accepted: 06/24/2022] [Indexed: 11/20/2022]
Abstract
Vsx2 is a transcription factor essential for retinal proliferation and bipolar cell differentiation, but the molecular mechanisms underlying its developmental roles are unclear. Here, we have profiled VSX2 genomic occupancy during mouse retinogenesis, revealing extensive retinal genetic programs associated with VSX2 during development. VSX2 binds and transactivates its enhancer in association with the transcription factor PAX6. Mice harboring deletions in the Vsx2 regulatory landscape exhibit specific abnormalities in retinal proliferation and in bipolar cell differentiation. In one of those deletions, a complete loss of bipolar cells is associated with a bias towards photoreceptor production. VSX2 occupies cis-regulatory elements nearby genes associated with photoreceptor differentiation and homeostasis in the adult mouse and human retina, including a conserved region nearby Prdm1, a factor implicated in the specification of rod photoreceptors and suppression of bipolar cell fate. VSX2 interacts with the transcription factor OTX2 and can act to suppress OTX2-dependent enhancer transactivation of the Prdm1 enhancer. Taken together, our analyses indicate that Vsx2 expression can be temporally and spatially uncoupled at the enhancer level, and they illuminate important mechanistic insights into how VSX2 is engaged with gene regulatory networks that are essential for retinal proliferation and cell fate acquisition.
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Affiliation(s)
- Fuyun Bian
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Marwa Daghsni
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Fangfang Lu
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Ophthalmology, The Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Silvia Liu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Jeffrey M Gross
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Issam Aldiri
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
- Louis J. Fox Center for Vision Restoration, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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6
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Hamad L, Kreidieh K, Hamdan MB, Nakouzi G, Yazbek S. Mapping the Diverse Genetic Disorders and Rare Diseases Among the Syrian Population: Implications on Refugee Health and Health Services in Host Countries. J Immigr Minor Health 2021; 22:1347-1367. [PMID: 32172498 DOI: 10.1007/s10903-020-00987-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The aim of this systematic review is to provide physicians and researchers with a comprehensive list of reported genetic disorders in patients of Syrian origin-those who have become part of the largest displaced population globally-and to highlight the need to consider migrant population-based risk for the development of genetic disease control and prevention programs. This review was performed based on the 2015 PRISMA and the international prospective register of systematic reviews. The present review reports on a total of 166 genetic disorders (only 128 reported on OMIM) identified in the Syrian population. Of these disorders, 27% are endocrine-, nutritional- and metabolic-related diseases. Second to metabolic disorders are congenital malformations, deformations and chromosomal abnormalities. Diseases of the blood and the blood-forming organs accounted for 13% of the total genetic disorders. The majority of the genetic disorders reported in Syrian patients followed an autosomal recessive mode of inheritance. These findings are a reflection of the high rates of consanguineous marriages that favor the increase in incidence of these diseases. From the diseases that followed an autosomal recessive mode of inheritance, 22% are reported to be only present in Syria and other regional countries. Twelve of these genetic diseases were identified to be strictly diagnosed in individuals of Syrian origin. The present systematic review highlights the need to develop programs that target genetic disorders affecting Syrian migrants in host countries. These programs would have potential financial and economic benefits, as well as a positive impact on the physical and mental health of members of the Syrian refugee community and those of their host societies. In turn, this would decrease the burden on the health systems in host countries.
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Affiliation(s)
- Lina Hamad
- Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Khalil Kreidieh
- Office of Faculty Affairs, Faculty of Medicine, American University of Beirut, Beirut, Lebanon
| | - Mirna Bou Hamdan
- Medical Laboratory Sciences Program, Faculty of Health Sciences, American University of Beirut, Riad El Solh, P.O Box 11-0236, Beirut, 1107 2020, Lebanon
| | - Ghunwa Nakouzi
- Department of Clinical Pathology, Cleveland Clinic Hospital, Cleveland, OH, USA.
| | - Soha Yazbek
- Medical Laboratory Sciences Program, Faculty of Health Sciences, American University of Beirut, Riad El Solh, P.O Box 11-0236, Beirut, 1107 2020, Lebanon.
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7
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Eintracht J, Corton M, FitzPatrick D, Moosajee M. CUGC for syndromic microphthalmia including next-generation sequencing-based approaches. Eur J Hum Genet 2020; 28:679-690. [PMID: 31896778 PMCID: PMC7171178 DOI: 10.1038/s41431-019-0565-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 11/26/2019] [Accepted: 12/03/2019] [Indexed: 01/29/2023] Open
Affiliation(s)
| | - Marta Corton
- Department of Genetics, IIS-University Hospital Fundación Jiménez Díaz-CIBERER, Madrid, Spain
| | | | - Mariya Moosajee
- UCL Institute of Ophthalmology, London, UK.
- Moorfields Eye Hospital NHS Foundation Trust, London, UK.
- Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK.
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8
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George A, Cogliati T, Brooks BP. Genetics of syndromic ocular coloboma: CHARGE and COACH syndromes. Exp Eye Res 2020; 193:107940. [PMID: 32032630 DOI: 10.1016/j.exer.2020.107940] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Revised: 01/20/2020] [Accepted: 01/22/2020] [Indexed: 02/07/2023]
Abstract
Optic fissure closure defects result in uveal coloboma, a potentially blinding condition affecting between 0.5 and 2.6 per 10,000 births that may cause up to 10% of childhood blindness. Uveal coloboma is on a phenotypic continuum with microphthalmia (small eye) and anophthalmia (primordial/no ocular tissue), the so-called MAC spectrum. This review gives a brief overview of the developmental biology behind coloboma and its clinical presentation/spectrum. Special attention will be given to two prominent, syndromic forms of coloboma, namely, CHARGE (Coloboma, Heart defect, Atresia choanae, Retarded growth and development, Genital hypoplasia, and Ear anomalies/deafness) and COACH (Cerebellar vermis hypoplasia, Oligophrenia, Ataxia, Coloboma, and Hepatic fibrosis) syndromes. Approaches employed to identify genes involved in optic fissure closure in animal models and recent advances in live imaging of zebrafish eye development are also discussed.
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Affiliation(s)
- Aman George
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health. Bethesda, Maryland, 20892, USA
| | - Tiziana Cogliati
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health. Bethesda, Maryland, 20892, USA
| | - Brian P Brooks
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health. Bethesda, Maryland, 20892, USA.
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9
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Mayer AK, Balousha G, Sharkia R, Mahajnah M, Ayesh S, Schulze M, Buchert R, Zobor D, Azem A, Schöls L, Bauer P, Wissinger B. Unraveling the genetic cause of hereditary ophthalmic disorders in Arab societies from Israel and the Palestinian Authority. Eur J Hum Genet 2020; 28:742-753. [PMID: 31896775 DOI: 10.1038/s41431-019-0566-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 11/12/2019] [Accepted: 12/10/2019] [Indexed: 11/09/2022] Open
Abstract
Visual impairment due to inherited ophthalmic disorders is amongst the most common disabilities observed in populations practicing consanguineous marriages. Here we investigated the molecular genetic basis of an unselected broad range of ophthalmic disorders in 20 consanguineous families from Arab villages of Israel and the Palestinian Authority. Most patients had little or very poor prior clinical workup and were recruited in a field study. Homozygosity mapping followed by candidate gene sequencing applying conventional Sanger sequencing or targeted next generation sequencing was performed in six families. In the remaining 14 families, one affected subject per family was chosen for whole exome sequencing. We discovered likely disease-causing variants, all homozygous, in 19 of 20 independent families (95%) including a previously reported novel disease gene for congenital nystagmus associated with foveal hypoplasia. Moreover, we found a family in which disease-causing variants for two collagenopathies - Stickler and Knobloch syndrome - segregate within a large sibship. Nine of the 19 distinct variants observed in this study were novel. Our study demonstrated a very high molecular diagnostic yield for a highly diverse spectrum of rare ophthalmic disorders in Arab patients from Israel and the Palestinian Authority, even with very limited prior clinical investigation. We conclude that 'genetic testing first' may be an economic way to direct clinical care and to support proper genetic counseling and risk assessment in these families.
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Affiliation(s)
- Anja K Mayer
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany.,Praxis fuer Humangenetik Tuebingen, Tuebingen, Germany
| | - Ghassan Balousha
- Department of Pathology and Histology, Al-Quds University, Eastern Jerusalem, Palestinian Authority, Jerusalem, Israel
| | - Rajech Sharkia
- The Triangle Regional Research and Development Center, Kfar Qari', Israel.,Beit-Berl Academic College, Beit-Berl, Israel
| | - Muhammad Mahajnah
- Child Neurology and Development Center, Hillel-Yaffe Medical Center, Hadera, Israel.,The Ruth and Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel
| | - Suhail Ayesh
- Molecular Genetic Laboratory, Al-Makassed Islamic Charitable Society Hospital, Jerusalem, Israel
| | - Martin Schulze
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany.,Praxis fuer Humangenetik Tuebingen, Tuebingen, Germany
| | - Rebecca Buchert
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Ditta Zobor
- University Eye Hospital, University of Tuebingen, Tuebingen, Germany
| | - Abdussalam Azem
- The School of Neurobiology, Biochemistry and Biophysics, George S. Wise faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Ludger Schöls
- Hertie Institute for Brain Research, University of Tuebingen, Tuebingen, Germany.,German Center of Neurodegenerative Diseases (DZNE), Tuebingen, Germany
| | - Peter Bauer
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Molecular Genetics Laboratory, Tuebingen, Germany.
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10
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Norrie JL, Lupo MS, Xu B, Al Diri I, Valentine M, Putnam D, Griffiths L, Zhang J, Johnson D, Easton J, Shao Y, Honnell V, Frase S, Miller S, Stewart V, Zhou X, Chen X, Dyer MA. Nucleome Dynamics during Retinal Development. Neuron 2019; 104:512-528.e11. [PMID: 31493975 PMCID: PMC6842117 DOI: 10.1016/j.neuron.2019.08.002] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 06/02/2019] [Accepted: 07/29/2019] [Indexed: 01/28/2023]
Abstract
More than 8,000 genes are turned on or off as progenitor cells produce the 7 classes of retinal cell types during development. Thousands of enhancers are also active in the developing retinae, many having features of cell- and developmental stage-specific activity. We studied dynamic changes in the 3D chromatin landscape important for precisely orchestrated changes in gene expression during retinal development by ultra-deep in situ Hi-C analysis on murine retinae. We identified developmental-stage-specific changes in chromatin compartments and enhancer-promoter interactions. We developed a machine learning-based algorithm to map euchromatin and heterochromatin domains genome-wide and overlaid it with chromatin compartments identified by Hi-C. Single-cell ATAC-seq and RNA-seq were integrated with our Hi-C and previous ChIP-seq data to identify cell- and developmental-stage-specific super-enhancers (SEs). We identified a bipolar neuron-specific core regulatory circuit SE upstream of Vsx2, whose deletion in mice led to the loss of bipolar neurons.
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Affiliation(s)
- Jackie L Norrie
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Marybeth S Lupo
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Beisi Xu
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Issam Al Diri
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Marc Valentine
- Cytogenetics Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Daniel Putnam
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Lyra Griffiths
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jiakun Zhang
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Dianna Johnson
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - John Easton
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Ying Shao
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Victoria Honnell
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Sharon Frase
- Cellular Imaging Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Shondra Miller
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Valerie Stewart
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xin Zhou
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xiang Chen
- Department of Computational Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Michael A Dyer
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA; Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN 38163, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA.
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11
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An update on the genetics of ocular coloboma. Hum Genet 2019; 138:865-880. [PMID: 31073883 DOI: 10.1007/s00439-019-02019-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 04/19/2019] [Indexed: 01/04/2023]
Abstract
Ocular coloboma is an uncommon, but often severe, sight-threatening condition that can be identified from birth. This congenital anomaly is thought to be caused by maldevelopment of optic fissure closure during early eye morphogenesis. It has been causally linked to both inherited (genetic) and environmental influences. In particular, as a consequence of work to identify genetic causes of coloboma, new molecular pathways that control optic fissure closure have now been identified. Many more regulatory mechanisms still await better understanding to inform on the development of potential therapies for patients with this malformation. This review provides an update of known coloboma genes, the pathways they influence and how best to manage the condition. In the age of precision medicine, determining the underlying genetic cause in any given patient is of high importance.
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12
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Matías-Pérez D, García-Montaño LA, Cruz-Aguilar M, García-Montalvo IA, Nava-Valdéz J, Barragán-Arevalo T, Villanueva-Mendoza C, Villarroel CE, Guadarrama-Vallejo C, la Cruz RVD, Chacón-Camacho O, Zenteno JC. Identification of novel pathogenic variants and novel gene-phenotype correlations in Mexican subjects with microphthalmia and/or anophthalmia by next-generation sequencing. J Hum Genet 2018; 63:1169-1180. [PMID: 30181649 DOI: 10.1038/s10038-018-0504-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 07/21/2018] [Accepted: 08/03/2018] [Indexed: 01/01/2023]
Abstract
Severe congenital eye malformations, particularly microphthalmia and anophthalmia, are one of the main causes of visual handicap worldwide. They can arise from multifactorial, chromosomal, or monogenic factors and can be associated with extensive clinical variability. Genetic analysis of individuals with these defects has allowed the recognition of dozens of genes whose mutations lead to disruption of normal ocular embryonic development. Recent application of next generation sequencing (NGS) techniques for genetic screening of patients with congenital eye defects has greatly improved the recognition of monogenic cases. In this study, we applied clinical exome NGS to a group of 14 Mexican patients (including 7 familial and 7 sporadic cases) with microphthalmia and/or anophthalmia. Causal or likely causal pathogenic variants were demonstrated in ~60% (8 out of 14 patients) individuals. Seven out of 8 different identified mutations occurred in well-known microphthalmia/anophthalmia genes (OTX2, VSX2, MFRP, VSX1) or in genes associated with syndromes that include ocular defects (CHD7, COL4A1) (including two instances of CHD7 pathogenic variants). A single pathogenic variant was identified in PIEZO2, a gene that was not previously associated with isolated ocular defects. NGS efficiently identified the genetic etiology of microphthalmia/anophthalmia in ~60% of cases included in this cohort, the first from Mexican origin analyzed to date. The molecular defects identified through clinical exome sequencing in this study expands the phenotypic spectra of CHD7-associated disorders and implicate PIEZO2 as a candidate gene for major eye developmental defects.
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Affiliation(s)
| | - Leopoldo A García-Montaño
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Marisa Cruz-Aguilar
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | | | - Jessica Nava-Valdéz
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Tania Barragán-Arevalo
- Department of Human Genetics, National Institute of Pediatrics of Mexico, Mexico City, Mexico
| | - Cristina Villanueva-Mendoza
- Department of Genetics, Hospital "Dr. Luis Sanchez Bulnes", Asociación Para Evitar la Ceguera en México, Mexico City, Mexico
| | - Camilo E Villarroel
- Department of Human Genetics, National Institute of Pediatrics of Mexico, Mexico City, Mexico
| | - Clavel Guadarrama-Vallejo
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Rocío Villafuerte-de la Cruz
- Ciencias Basicas, Escuela de Medicina, Instituto Tecnológico y de Estudios Superiores de Monterrey, Monterrey, NL, Mexico
| | - Oscar Chacón-Camacho
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico
| | - Juan C Zenteno
- Department of Genetics-Research Unit, Institute of Ophthalmology "Conde de Valenciana", Mexico City, Mexico. .,Department of Biochemistry, Faculty of Medicine, UNAM, Mexico City, Mexico.
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13
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Genes and pathways in optic fissure closure. Semin Cell Dev Biol 2017; 91:55-65. [PMID: 29198497 DOI: 10.1016/j.semcdb.2017.10.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/29/2017] [Accepted: 10/10/2017] [Indexed: 12/22/2022]
Abstract
Embryonic development of the vertebrate eye begins with the formation of an optic vesicle which folds inwards to form a double-layered optic cup with a fissure on the ventral surface, known as the optic fissure. Closure of the optic fissure is essential for subsequent growth and development of the eye. A defect in this process can leave a gap in the iris, retina or optic nerve, known as a coloboma, which can lead to severe visual impairment. This review brings together current information about genes and pathways regulating fissure closure from human coloboma patients and animal models. It focuses especially on current understanding of the morphological changes and processes of epithelial remodelling occurring at the fissure margins.
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14
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Ledford KL, Martinez-De Luna RI, Theisen MA, Rawlins KD, Viczian AS, Zuber ME. Distinct cis-acting regions control six6 expression during eye field and optic cup stages of eye formation. Dev Biol 2017; 426:418-428. [PMID: 28438336 PMCID: PMC5500183 DOI: 10.1016/j.ydbio.2017.04.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/07/2017] [Accepted: 04/12/2017] [Indexed: 02/06/2023]
Abstract
The eye field transcription factor, Six6, is essential for both the early (specification and proliferative growth) phase of eye formation, as well as for normal retinal progenitor cell differentiation. While genomic regions driving six6 optic cup expression have been described, the sequences controlling eye field and optic vesicle expression are unknown. Two evolutionary conserved regions 5' and a third 3' to the six6 coding region were identified, and together they faithfully replicate the endogenous X. laevis six6 expression pattern. Transgenic lines were generated and used to determine the onset and expression patterns controlled by the regulatory regions. The conserved 3' region was necessary and sufficient for eye field and optic vesicle expression. In contrast, the two conserved enhancer regions located 5' of the coding sequence were required together for normal optic cup and mature retinal expression. Gain-of-function experiments indicate endogenous six6 and GFP expression in F1 transgenic embryos are similarly regulated in response to candidate trans-acting factors. Importantly, CRISPR/CAS9-mediated deletion of the 3' eye field/optic vesicle enhancer in X. laevis, resulted in a reduction in optic vesicle size. These results identify the cis-acting regions, demonstrate the modular nature of the elements controlling early versus late retinal expression, and identify potential regulators of six6 expression during the early stages of eye formation.
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Affiliation(s)
- Kelley L Ledford
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Reyna I Martinez-De Luna
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Matthew A Theisen
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Karisa D Rawlins
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States
| | - Andrea S Viczian
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Cell & Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, United States.
| | - Michael E Zuber
- Department of Ophthalmology and The Center for Vision Research, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Biochemistry & Molecular Biology, SUNY Upstate Medical University, Syracuse, NY 13210, United States; Department of Neuroscience & Physiology, SUNY Upstate Medical University, Syracuse, NY 13210, United States
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15
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Ammar THA, Ismail S, Mansour OAAM, El-Shafey MM, Doghish AS, Kamal AM, Abdel-Salam GMH. Genetic analysis of SOX2 and VSX2 genes in 27 Egyptian families with anophthalmia and microphthalmia. Ophthalmic Genet 2017; 38:498-500. [PMID: 28121235 DOI: 10.1080/13816810.2017.1279184] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Tamer H A Ammar
- a Medical Molecular Genetics Department , Human Genetics and Genome Research Division, National Research Centre , Cairo , Egypt
| | - Somaia Ismail
- a Medical Molecular Genetics Department , Human Genetics and Genome Research Division, National Research Centre , Cairo , Egypt
| | | | - Mostafa M El-Shafey
- b Biochemistry Department , Faculty of Pharmacy, Al-Azhar University , Cairo , Egypt
| | - Ahmed S Doghish
- b Biochemistry Department , Faculty of Pharmacy, Al-Azhar University , Cairo , Egypt
| | - Ahmad M Kamal
- c Ophthalmology Department , Cairo University , Cairo , Egypt
| | - Ghada M H Abdel-Salam
- d Clinical Genetics Department , Human Genetics and Genome Research Division, National Research Centre , Cairo , Egypt
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16
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Clinical utility gene card for: Non-Syndromic Microphthalmia Including Next-Generation Sequencing-Based Approaches. Eur J Hum Genet 2017; 25:ejhg2016201. [PMID: 28098148 DOI: 10.1038/ejhg.2016.201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 11/28/2016] [Accepted: 12/14/2016] [Indexed: 11/08/2022] Open
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17
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Carbone MA, Yamamoto A, Huang W, Lyman RA, Meadors TB, Yamamoto R, Anholt RRH, Mackay TFC. Genetic architecture of natural variation in visual senescence in Drosophila. Proc Natl Acad Sci U S A 2016; 113:E6620-E6629. [PMID: 27791033 PMCID: PMC5087026 DOI: 10.1073/pnas.1613833113] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Senescence, i.e., functional decline with age, is a major determinant of health span in a rapidly aging population, but the genetic basis of interindividual variation in senescence remains largely unknown. Visual decline and age-related eye disorders are common manifestations of senescence, but disentangling age-dependent visual decline in human populations is challenging due to inability to control genetic background and variation in histories of environmental exposures. We assessed the genetic basis of natural variation in visual senescence by measuring age-dependent decline in phototaxis using Drosophila melanogaster as a genetic model system. We quantified phototaxis at 1, 2, and 4 wk of age in the sequenced, inbred lines of the Drosophila melanogaster Genetic Reference Panel (DGRP) and found an average decline in phototaxis with age. We observed significant genetic variation for phototaxis at each age and significant genetic variation in senescence of phototaxis that is only partly correlated with phototaxis. Genome-wide association analyses in the DGRP and a DGRP-derived outbred, advanced intercross population identified candidate genes and genetic networks associated with eye and nervous system development and function, including seven genes with human orthologs previously associated with eye diseases. Ninety percent of candidate genes were functionally validated with targeted RNAi-mediated suppression of gene expression. Absence of candidate genes previously implicated with longevity indicates physiological systems may undergo senescence independent of organismal life span. Furthermore, we show that genes that shape early developmental processes also contribute to senescence, demonstrating that senescence is part of a genetic continuum that acts throughout the life span.
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Affiliation(s)
- Mary Anna Carbone
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695; W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695; Program in Genetics, North Carolina State University, Raleigh, NC 27695
| | - Akihiko Yamamoto
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695; W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695; Program in Genetics, North Carolina State University, Raleigh, NC 27695
| | - Wen Huang
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695; W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695; Program in Genetics, North Carolina State University, Raleigh, NC 27695; Initiative in Biological Complexity, North Carolina State University, Raleigh, NC 27695
| | - Rachel A Lyman
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Tess Brune Meadors
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Ryoan Yamamoto
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695
| | - Robert R H Anholt
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695; W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695; Program in Genetics, North Carolina State University, Raleigh, NC 27695; Initiative in Biological Complexity, North Carolina State University, Raleigh, NC 27695
| | - Trudy F C Mackay
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695; W. M. Keck Center for Behavioral Biology, North Carolina State University, Raleigh, NC 27695; Program in Genetics, North Carolina State University, Raleigh, NC 27695; Initiative in Biological Complexity, North Carolina State University, Raleigh, NC 27695
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18
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James A, Lee C, Williams AM, Angileri K, Lathrop KL, Gross JM. The hyaloid vasculature facilitates basement membrane breakdown during choroid fissure closure in the zebrafish eye. Dev Biol 2016; 419:262-272. [PMID: 27634568 DOI: 10.1016/j.ydbio.2016.09.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 09/09/2016] [Accepted: 09/09/2016] [Indexed: 12/22/2022]
Abstract
A critical aspect of vertebrate eye development is closure of the choroid fissure (CF). Defects in CF closure result in colobomas, which are a significant cause of childhood blindness worldwide. Despite the growing number of mutated loci associated with colobomas, we have a limited understanding of the cell biological underpinnings of CF closure. Here, we utilize the zebrafish embryo to identify key phases of CF closure and regulators of the process. Utilizing Laminin-111 as a marker for the basement membrane (BM) lining the CF, we determine the spatial and temporal patterns of BM breakdown in the CF, a prerequisite for CF closure. Similarly, utilizing a combination of in vivo time-lapse imaging, β-catenin immunohistochemistry and F-actin staining, we determine that tissue fusion, which serves to close the fissure, follows BM breakdown closely. Periocular mesenchyme (POM)-derived endothelial cells, which migrate through the CF to give rise to the hyaloid vasculature, possess distinct actin foci that correlate with regions of BM breakdown. Disruption of talin1, which encodes a regulator of the actin cytoskeleton, results in colobomas and these correlate with structural defects in the hyaloid vasculature and defects in BM breakdown. cloche mutants, which entirely lack a hyaloid vasculature, also possess defects in BM breakdown in the CF. Taken together, these data support a model in which the hyaloid vasculature and/or the POM-derived endothelial cells that give rise to the hyaloid vasculature contribute to BM breakdown during CF closure.
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Affiliation(s)
- Andrea James
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Chanjae Lee
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
| | - Andre M Williams
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
| | - Krista Angileri
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
| | - Kira L Lathrop
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
- Department of Bioengineering, University of Pittsburgh Swanson School of Engineering, Pittsburgh, PA 15213
| | - Jeffrey M Gross
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin TX, 78712
- Department of Ophthalmology, Louis J. Fox Center for Vision Restoration, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
- Department of Developmental Biology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213
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19
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Capowski EE, Wright LS, Liang K, Phillips MJ, Wallace K, Petelinsek A, Hagstrom A, Pinilla I, Borys K, Lien J, Min JH, Keles S, Thomson JA, Gamm DM. Regulation of WNT Signaling by VSX2 During Optic Vesicle Patterning in Human Induced Pluripotent Stem Cells. Stem Cells 2016; 34:2625-2634. [PMID: 27301076 DOI: 10.1002/stem.2414] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2016] [Accepted: 05/28/2016] [Indexed: 12/22/2022]
Abstract
Few gene targets of Visual System Homeobox 2 (VSX2) have been identified despite its broad and critical role in the maintenance of neural retina (NR) fate during early retinogenesis. We performed VSX2 ChIP-seq and ChIP-PCR assays on early stage optic vesicle-like structures (OVs) derived from human iPS cells (hiPSCs), which highlighted WNT pathway genes as direct regulatory targets of VSX2. Examination of early NR patterning in hiPSC-OVs from a patient with a functional null mutation in VSX2 revealed mis-expression and upregulation of WNT pathway components and retinal pigmented epithelium (RPE) markers in comparison to control hiPSC-OVs. Furthermore, pharmacological inhibition of WNT signaling rescued the early mutant phenotype, whereas augmentation of WNT signaling in control hiPSC-OVs phenocopied the mutant. These findings reveal an important role for VSX2 as a regulator of WNT signaling and suggest that VSX2 may act to maintain NR identity at the expense of RPE in part by direct repression of WNT pathway constituents. Stem Cells 2016;34:2625-2634.
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Affiliation(s)
| | - Lynda S Wright
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Kun Liang
- Statistics and Actuarial Science, University of Waterloo, Waterloo, ON, Canada
| | - M Joseph Phillips
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Kyle Wallace
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Anna Petelinsek
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Anna Hagstrom
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Isabel Pinilla
- Aragon Institute for Health Research (IIS Aragón), Lozano Blesa University Hospital, Zaragoza, 50009, Spain.,Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza, 50009, Spain
| | - Katarzyna Borys
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jessica Lien
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jee Hong Min
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Sunduz Keles
- Department of Statistics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | | | - David M Gamm
- Waisman Center, University of Wisconsin-Madison, Madison, WI, 53705, USA.,McPherson Eye Research Institute, University of Wisconsin-Madison, Madison, WI, 53705, USA.,Department of Ophthamology and Visual Sciences, University of Wisconsin-Madison, Madison, WI, 53705, USA
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20
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Wright LS, Pinilla I, Saha J, Clermont JM, Lien JS, Borys KD, Capowski EE, Phillips MJ, Gamm DM. VSX2 and ASCL1 Are Indicators of Neurogenic Competence in Human Retinal Progenitor Cultures. PLoS One 2015; 10:e0135830. [PMID: 26292211 PMCID: PMC4546156 DOI: 10.1371/journal.pone.0135830] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 07/27/2015] [Indexed: 01/09/2023] Open
Abstract
Three dimensional (3D) culture techniques are frequently used for CNS tissue modeling and organoid production, including generation of retina-like tissues. A proposed advantage of these 3D systems is their potential to more closely approximate in vivo cellular microenvironments, which could translate into improved manufacture and/or maintenance of neuronal populations. Visual System Homeobox 2 (VSX2) labels all multipotent retinal progenitor cells (RPCs) and is known to play important roles in retinal development. In contrast, the proneural transcription factor Acheate scute-like 1 (ASCL1) is expressed transiently in a subset of RPCs, but is required for the production of most retinal neurons. Therefore, we asked whether the presence of VSX2 and ASCL1 could gauge neurogenic potential in 3D retinal cultures derived from human prenatal tissue or ES cells (hESCs). Short term prenatal 3D retinal cultures displayed multiple characteristics of human RPCs (hRPCs) found in situ, including robust expression of VSX2. Upon initiation of hRPC differentiation, there was a small increase in co-labeling of VSX2+ cells with ASCL1, along with a modest increase in the number of PKCα+ neurons. However, 3D prenatal retinal cultures lost expression of VSX2 and ASCL1 over time while concurrently becoming refractory to neuronal differentiation. Conversely, 3D optic vesicles derived from hESCs (hESC-OVs) maintained a robust VSX2+ hRPC population that could spontaneously co-express ASCL1 and generate photoreceptors and other retinal neurons for an extended period of time. These results show that VSX2 and ASCL1 can serve as markers for neurogenic potential in cultured hRPCs. Furthermore, unlike hESC-OVs, maintenance of 3D structure does not independently convey an advantage in the culture of prenatal hRPCs, further illustrating differences in the survival and differentiation requirements of hRPCs extracted from native tissue vs. those generated entirely in vitro.
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Affiliation(s)
- Lynda S. Wright
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Isabel Pinilla
- Department of Ophthalmology, Lozano Blesa University Hospital, Zaragoza, Spain
- Aragones Health Sciences Institute, Zaragoza, Spain
| | - Jishnu Saha
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Joshua M. Clermont
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- New England College of Optometry, Boston, Massachusetts, United States of America
| | - Jessica S. Lien
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Katarzyna D. Borys
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Elizabeth E. Capowski
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
| | - M. Joseph Phillips
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
| | - David M. Gamm
- Waisman Center, University of Wisconsin, Madison, Wisconsin, United States of America
- McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin, United States of America
- Department of Ophthalmology and Visual Sciences, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail:
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21
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Reis LM, Semina EV. Conserved genetic pathways associated with microphthalmia, anophthalmia, and coloboma. ACTA ACUST UNITED AC 2015; 105:96-113. [PMID: 26046913 DOI: 10.1002/bdrc.21097] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 05/13/2015] [Indexed: 12/19/2022]
Abstract
The human eye is a complex organ whose development requires extraordinary coordination of developmental processes. The conservation of ocular developmental steps in vertebrates suggests possible common genetic mechanisms. Genetic diseases involving the eye represent a leading cause of blindness in children and adults. During the last decades, there has been an exponential increase in genetic studies of ocular disorders. In this review, we summarize current success in identification of genes responsible for microphthalmia, anophthalmia, and coloboma (MAC) phenotypes, which are associated with early defects in embryonic eye development. Studies in animal models for the orthologous genes identified overlapping phenotypes for most factors, confirming the conservation of their function in vertebrate development. These animal models allow for further investigation of the mechanisms of MAC, integration of various identified genes into common developmental pathways and finally, provide an avenue for the development and testing of therapeutic interventions.
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Affiliation(s)
- Linda M Reis
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Elena V Semina
- Department of Pediatrics and Children's Research Institute, Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin.,Department of Cell Biology Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin
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22
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Sigulinsky CL, German ML, Leung AM, Clark AM, Yun S, Levine EM. Genetic chimeras reveal the autonomy requirements for Vsx2 in embryonic retinal progenitor cells. Neural Dev 2015; 10:12. [PMID: 25927996 PMCID: PMC4450477 DOI: 10.1186/s13064-015-0039-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 04/14/2015] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Vertebrate retinal development is a complex process, requiring the specification and maintenance of retinal identity, proliferative expansion of retinal progenitor cells (RPCs), and their differentiation into retinal neurons and glia. The homeobox gene Vsx2 is expressed in RPCs and required for the proper execution of this retinal program. However, our understanding of the mechanisms by which Vsx2 does this is still rudimentary. To define the autonomy requirements for Vsx2 in the regulation of RPC properties, we generated chimeric mouse embryos comprised of wild-type and Vsx2-deficient cells. RESULTS We show that Vsx2 maintains retinal identity in part through the cell-autonomous repression of the retinal pigment epithelium determinant Mitf, and that Lhx2 is required cell autonomously for the ectopic Mitf expression in Vsx2-deficient cells. We also found significant cell-nonautonomous contributions to Vsx2-mediated regulation of RPC proliferation, pointing to an important role for Vsx2 in establishing a growth-promoting extracellular environment. Additionally, we report a cell-autonomous requirement for Vsx2 in controlling when neurogenesis is initiated, indicating that Vsx2 is an important mediator of neurogenic competence. Finally, the distribution of wild-type cells shifted away from RPCs and toward retinal ganglion cell precursors in patches of high Vsx2-deficient cell density to potentially compensate for the lack of fated precursors in these areas. CONCLUSIONS Through the generation and analysis of genetic chimeras, we demonstrate that Vsx2 utilizes both cell-autonomous and cell-nonautonomous mechanisms to regulate progenitor properties in the embryonic retina. Importantly, Vsx2's role in regulating Mitf is in part separable from its role in promoting proliferation, and proliferation is excluded as the intrinsic timer that determines when neurogenesis is initiated. These findings highlight the complexity of Vsx2 function during retinal development and provide a framework for identifying the molecular mechanisms mediating these functions.
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Affiliation(s)
- Crystal L Sigulinsky
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Interdepartmental Program in Neuroscience, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Massiell L German
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Amanda M Leung
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Anna M Clark
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
| | - Sanghee Yun
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
| | - Edward M Levine
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, 65 Mario Capecchi Drive, Salt Lake City, UT, 84132, USA.
- Department of Neurobiology and Anatomy, University of Utah, 20 North 1900 East, Salt Lake City, UT, 84132, USA.
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Williamson KA, FitzPatrick DR. The genetic architecture of microphthalmia, anophthalmia and coloboma. Eur J Med Genet 2014; 57:369-80. [PMID: 24859618 DOI: 10.1016/j.ejmg.2014.05.002] [Citation(s) in RCA: 167] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Accepted: 05/14/2014] [Indexed: 10/25/2022]
Abstract
Microphthalmia, anophthalmia and coloboma (MAC) are distinct phenotypes that represent a continuum of structural developmental eye defects. In severe bilateral cases (anophthalmia or severe microphthalmia) the genetic cause is now identifiable in approximately 80 percent of cases, with de novo heterozygous loss-of-function mutations in SOX2 or OTX2 being the most common. The genetic cause of other forms of MAC, in particular isolated coloboma, remains unknown in the majority of cases. This review will focus on MAC phenotypes that are associated with mutation of the genes SOX2, OTX2, PAX6, STRA6, ALDH1A3, RARB, VSX2, RAX, FOXE3, BMP4, BMP7, GDF3, GDF6, ABCB6, ATOH7, C12orf57, TENM3 (ODZ3), and VAX1. Recently reported mutation of the SALL2 and YAP1 genes are discussed in brief. Clinical and genetic features were reviewed in a total of 283 unrelated MAC cases or families that were mutation-positive from these 20 genes. Both the relative frequency of mutations in MAC cohort screens and the level of confidence in the assignment of disease-causing status were evaluated for each gene.
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Affiliation(s)
- Kathleen A Williamson
- Medical Research Council Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK
| | - David R FitzPatrick
- Medical Research Council Human Genetics Unit, MRC Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh EH4 2XU, UK.
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Kelberman D, Islam L, Lakowski J, Bacchelli C, Chanudet E, Lescai F, Patel A, Stupka E, Buck A, Wolf S, Beales PL, Jacques TS, Bitner-Glindzicz M, Liasis A, Lehmann OJ, Kohlhase J, Nischal KK, Sowden JC. Mutation of SALL2 causes recessive ocular coloboma in humans and mice. Hum Mol Genet 2014; 23:2511-26. [PMID: 24412933 PMCID: PMC3990155 DOI: 10.1093/hmg/ddt643] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Ocular coloboma is a congenital defect resulting from failure of normal closure of the optic fissure during embryonic eye development. This birth defect causes childhood blindness worldwide, yet the genetic etiology is poorly understood. Here, we identified a novel homozygous mutation in the SALL2 gene in members of a consanguineous family affected with non-syndromic ocular coloboma variably affecting the iris and retina. This mutation, c.85G>T, introduces a premature termination codon (p.Glu29*) predicted to truncate the SALL2 protein so that it lacks three clusters of zinc-finger motifs that are essential for DNA-binding activity. This discovery identifies SALL2 as the third member of the Drosophila homeotic Spalt-like family of developmental transcription factor genes implicated in human disease. SALL2 is expressed in the developing human retina at the time of, and subsequent to, optic fissure closure. Analysis of Sall2-deficient mouse embryos revealed delayed apposition of the optic fissure margins and the persistence of an anterior retinal coloboma phenotype after birth. Sall2-deficient embryos displayed correct posterior closure toward the optic nerve head, and upon contact of the fissure margins, dissolution of the basal lamina occurred and PAX2, known to be critical for this process, was expressed normally. Anterior closure was disrupted with the fissure margins failing to meet, or in some cases misaligning leading to a retinal lesion. These observations demonstrate, for the first time, a role for SALL2 in eye morphogenesis and that loss of function of the gene causes ocular coloboma in humans and mice.
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Khan AO, Aldahmesh MA, Noor J, Salem A, Alkuraya FS. Lens subluxation and retinal dysfunction in a girl with homozygous VSX2 mutation. Ophthalmic Genet 2013; 36:8-13. [PMID: 24001013 DOI: 10.3109/13816810.2013.827217] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE To describe a unique lens subluxation phenotype in a child from a consanguineous family and to determine its genetic basis. METHODS Ophthalmologic examination (including ocular biometry and electroretinography [ERG] for the proband) and autozygosity-analysis-guided exome sequencing for the family; confirmatory candidate gene sequencing in the family and ethnically matched controls. RESULTS An otherwise healthy 3-year-old Saudi Arabian girl with poor vision since birth had smooth irides, lens subluxation, cone-rod dysfunction, and high myopia - features resembling Knobloch syndrome but differing in regard to direction of lens subluxation (superior rather than temporal) and the pattern of chorioretinal atrophy (without vitreous condensations or distinct macular atrophy). Autozygome-guided exome sequencing revealed the girl to harbor a homozygous exon 5 mutation in the ocular transcription factor gene visual homeobox 2 (VSX2) [c.773delA; p.Lys258SerfsX44] that was heterozygous in the unaffected brother and parents and absent in 100 healthy ethnically matched controls and on-line databases. Previously reported VSX2 mutations have affected the DNA-binding domains and only been associated with microphthalmia. Unlike previously reported mutations, the current VSX2 mutation is downstream to the protein's DNA binding domains. CONCLUSIONS The phenotype of this girl is unique and suggests a normal regulatory role for VSX2 in iris, zonule, and cone-rod development. For a consanguineous family with suspected recessive ocular disease but without a clear candidate gene, autozygome-guided exome analysis is a powerful technique, even when only a single patient is affected.
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Affiliation(s)
- Arif O Khan
- Division of Pediatric Ophthalmology, King Khaled Eye Specialist Hospital , Riyadh , Saudi Arabia
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Posterior microphthalmia and nanophthalmia in Tunisia caused by a founder c.1059_1066insC mutation of the PRSS56 gene. Gene 2013; 528:288-94. [PMID: 23820083 DOI: 10.1016/j.gene.2013.06.045] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2013] [Accepted: 06/10/2013] [Indexed: 01/08/2023]
Abstract
Congenital microphthalmia (CMIC) is a common developmental ocular disorder characterized by a small, and sometimes malformed, eye. Posterior microphthalmia (PM) and nanophthalmia are two rare subtypes of isolated CMIC characterized by extreme hyperopia due to short axial length and elevated lens/eye volume ratio. While nanophthalmia is associated with a reduced size in both anterior and posterior segments, PM involves a normal-size anterior chamber but a small posterior segment. Several genes encoding transcription and non-transcription regulators have been identified in different forms of CMIC. MFRP gene mutations have, for instance, been associated with nanophthalmia, and mutations in the recently identified PRSS56 gene have been linked to PM. So far, these two forms of CMIC have been associated with 9 mutations in PRSS56. Of particular interest, a c.1059_1066insC mutation has recently been reported in four Tunisian families with isolated PM and one Tunisian family with nanophthalmia. Here, we performed a genome-wide scan using a high density single nucleotide polymorphism (SNP) array 50 K in a large consanguineous Tunisian family (PM7) affected with PM and identified the same causative disease mutation. A total of 24 polymorphic markers spanning the PRSS56 gene in 6 families originating from different regions of Tunisia were analyzed to investigate the origin of the c.1059_1066insC mutation and to determine whether it arose in a common ancestor. A highly significant disease-associated haplotype, spanning across the 146 kb of the 2q37.1 chromosome, was conserved in those families, suggesting that c.1059_1066insC arose from a common founder. The age of the mutation in this haplotype was estimated to be around 1,850 years. The identification of such 'founder effects' may greatly simplify diagnostic genetic screening and lead to better prognostic counseling.
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Zou C, Levine EM. Vsx2 controls eye organogenesis and retinal progenitor identity via homeodomain and non-homeodomain residues required for high affinity DNA binding. PLoS Genet 2012; 8:e1002924. [PMID: 23028343 PMCID: PMC3447932 DOI: 10.1371/journal.pgen.1002924] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Accepted: 07/05/2012] [Indexed: 12/26/2022] Open
Abstract
The homeodomain and adjacent CVC domain in the visual system homeobox (VSX) proteins are conserved from nematodes to humans. Humans with missense mutations in these regions of VSX2 have microphthalmia, suggesting both regions are critical for function. To assess this, we generated the corresponding mutations in mouse Vsx2. The homeodomain mutant protein lacked DNA binding activity and the knock-in mutant phenocopied the null mutant, ocular retardation J. The CVC mutant protein exhibited weakened DNA binding; and, although the corresponding knock-in allele was recessive, it unexpectedly caused the strongest phenotype, as indicated by severe microphthalmia and hyperpigmentation of the neural retina. This occurred through a cryptic transcriptional feedback loop involving the transcription factors Mitf and Otx1 and the Cdk inhibitor p27Kip1. Our data suggest that the phenotypic severity of the CVC mutant depends on the weakened DNA binding activity elicited by the CVC mutation and a previously unknown protein interaction between Vsx2 and its regulatory target Mitf. Our data also suggest that an essential function of the CVC domain is to assist the homeodomain in high-affinity DNA binding, which is required for eye organogenesis and unhindered execution of the retinal progenitor program in mammals. Finally, the genetic and phenotypic behaviors of the CVC mutation suggest it has the characteristics of a recessive neomorph, a rare type of genetic allele. Problems with the early development of the mammalian retina can cause congenital eye defects such as microphthalmia, in which the eye is dramatically smaller and functionally compromised. Severe microphthalmia is associated with mutations in the retinal-expressed visual system homeobox 2 (Vsx2) gene, but how Vsx2 controls retinal development, and ultimately eye formation, has remained unclear. We assessed the impact of two missense mutations, discovered in humans, on Vsx2 function and eye development in mice. One mutation altered a highly conserved residue of the homeodomain, and the other altered a highly conserved residue in the CVC domain, a region of unresolved function. Both mutations impacted the DNA binding properties of the protein, although to differing extents. Likewise, both mutations caused microphthalmia and disruptions in retinal development, also to differing extents and by distinct mechanisms. Our data suggest that Vsx2 acts as a gatekeeper of the retinal gene expression program by preventing the activation of interfering or competing gene expression programs. We propose that the evolutionary stable association between the VSX-class homeodomain and CVC domain set the stage for Vsx2 or its archetype to assume a gatekeeper function for retinal development and ultimately eye organogenesis.
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Affiliation(s)
- Changjiang Zou
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
| | - Edward M. Levine
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah, United States of America
- * E-mail:
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28
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Slavotinek AM. Eye development genes and known syndromes. Mol Genet Metab 2011; 104:448-56. [PMID: 22005280 PMCID: PMC3224152 DOI: 10.1016/j.ymgme.2011.09.029] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2011] [Revised: 09/21/2011] [Accepted: 09/21/2011] [Indexed: 11/22/2022]
Abstract
Anophthalmia and microphthalmia (A/M) are significant eye defects because they can have profound effects on visual acuity. A/M is associated with non-ocular abnormalities in an estimated 33-95% of cases and around 25% of patients have an underlying genetic syndrome that is diagnosable. Syndrome recognition is important for targeted molecular genetic testing, prognosis and for counseling regarding recurrence risks. This review provides clinical and molecular information for several of the commonest syndromes associated with A/M: Anophthalmia-Esophageal-Genital syndrome, caused by SOX2 mutations, Anophthalmia and pituitary abnormalities caused by OTX2 mutations, Matthew-Wood syndrome caused by STRA6 mutations, oculofaciocardiodental syndrome and Lenz microphthalmia caused by BCOR mutations, Microphthalmia Linear Skin pigmentation syndrome caused by HCCS mutations, Anophthalmia, pituitary abnormalities, polysyndactyly caused by BMP4 mutations and Waardenburg anophthalmia caused by mutations in SMOC1. In addition, we briefly discuss the ocular and extraocular phenotypes associated with several other important eye developmental genes, including GDF6, VSX2, RAX, SHH, SIX6 and PAX6.
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Affiliation(s)
- Anne M Slavotinek
- Department of Pediatrics, Division of Genetics, University of California, San Francisco, San Francisco, CA 94143-0748, USA.
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29
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Use of genome-wide SNP homozygosity mapping in small pedigrees to identify new mutations in VSX2 causing recessive microphthalmia and a semidominant inner retinal dystrophy. Hum Genet 2010; 128:51-60. [DOI: 10.1007/s00439-010-0823-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2010] [Accepted: 04/01/2010] [Indexed: 01/08/2023]
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Reis LM, Tyler RC, Schneider A, Bardakjian T, Stoler JM, Melancon SB, Semina EV. FOXE3 plays a significant role in autosomal recessive microphthalmia. Am J Med Genet A 2010; 152A:582-90. [PMID: 20140963 DOI: 10.1002/ajmg.a.33257] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
FOXE3 forkhead transcription factor is essential to lens development in vertebrates. The eyes of Foxe3/foxe3-deficient mice and zebrafish fail to develop normally. In humans, autosomal dominant and recessive mutations in FOXE3 have been associated with variable phenotypes including anterior segment anomalies, cataract, and microphthalmia. We undertook sequencing of FOXE3 in 116 probands with a spectrum of ocular defects ranging from anterior segment dysgenesis and cataract to anophthalmia/microphthalmia. Recessive mutations in FOXE3 were found in four of 26 probands affected with bilateral microphthalmia (15% of all bilateral microphthalmia and 100% of consanguineous families with this phenotype). FOXE3-positive microphthalmia was accompanied by aphakia and/or corneal defects; no other associated systemic anomalies were observed in FOXE3-positive families. The previously reported c.720C > A (p.C240X) nonsense mutation was identified in two additional families in our sample and therefore appears to be recurrent, now reported in three independent microphthalmia families of varied ethnic backgrounds. Several missense variants were identified at varying frequencies in patient and control groups with some apparently being race-specific, which underscores the importance of utilizing race/ethnicity-matched control populations in evaluating the relevance of genetic screening results. In conclusion, FOXE3 mutations represent an important cause of nonsyndromic autosomal recessive bilateral microphthalmia.
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Affiliation(s)
- Linda M Reis
- Department of Pediatrics and Children's Research Institute at the Medical College of Wisconsin and Children's Hospital of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Segel R, Levy-Lahad E, Pasutto F, Picard E, Rauch A, Alterescu G, Schimmel MS. Pulmonary hypoplasia-diaphragmatic hernia-anophthalmia-cardiac defect (PDAC) syndrome due to STRA6 mutations--what are the minimal criteria? Am J Med Genet A 2010; 149A:2457-63. [PMID: 19839040 DOI: 10.1002/ajmg.a.33038] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Microphthalmic syndrome 9 (OMIM601186) is a genetically and phenotypically variable condition, comprising anophthalmia, pulmonary hypoplasia, diaphragmatic hernia, and cardiac malformations (PDAC syndrome). Reported cases have all been associated with fetal/neonatal death or developmental delay. Recessive stimulated by retinoic acid gene 6 homolog (STRA6) mutations have recently been identified as the cause of cases of PDAC in which distinct, "bushy" eyebrows have been observed. We describe a patient with clinical anophthalmia, bushy eyebrows, patent ductus arteriosus, and normal development at age 30 months, who is a compound heterozygote for two novel STRA6 missense mutations. This patient's phenotype is consistent with the multisystemic malformations of PDAC syndrome, but is somewhat milder. This is the first living patient with compound heterozygous STRA6 mutations, which may explain her milder phenotype. We conclude that STRA6 analysis should be considered in all patients with clinical anophthalmia. Genetic counseling should be cautious with respect to long-term developmental outcomes.
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Affiliation(s)
- Reeval Segel
- Medical Genetics Institute, Shaare Zedek Medical Center, Jerusalem, Israel.
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Fleckenstein M, Maumenee IH. Unilateral Isolated Microphthalmia Inherited as an Autosomal Recessive Trait. Ophthalmic Genet 2009; 26:163-8. [PMID: 16352476 DOI: 10.1080/13816810500468672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
PURPOSE To report a family with unilateral isolated microphthalmia showing an autosomal recessive pattern of inheritance. CASE REPORT We report a family in which three out of four children, one male and monozygotic female twins, were born with unilateral isolated microphthalmia to healthy consanguineous parents. One twin additionally had a horseshoe kidney. Rare cases of familial isolated microphthalmia/anophthalmia have been previously described. This is the first report of a family with autosomal recessive isolated microphthalmia occurring unilaterally in all affected individuals. It remains unknown how this inherited genetic disease results in unilateral manifestation. CONCLUSION Mirror imaging of this condition in the monozygotic twins may help elucidate the underlying mechanism. The constellation of features in this family may contribute to solve remaining questions of research into symmetry and asymmetry.
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Affiliation(s)
- Monika Fleckenstein
- The Wilmer Eye Institute, Johns Hopkins Hospital, Baltimore, Maryland 21287, USA.
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A genome-wide linkage scan in Tunisian families identifies a novel locus for non-syndromic posterior microphthalmia to chromosome 2q37.1. Hum Genet 2009; 126:575-87. [PMID: 19526372 DOI: 10.1007/s00439-009-0688-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 05/16/2009] [Indexed: 10/20/2022]
Abstract
Posterior microphthalmia (PM) is a relatively rare autosomal recessive condition with normal anterior segment and small posterior segment resulting in high hyperopia and retinal folding. It is an uncommon subtype of microphthalmia that has been mostly reported to coexist with several other ophthalmic conditions and to occur in sporadic cases. The membrane-type frizzled-related protein (MFRP) is the only gene so far reported implicated in autosomal recessive, non-syndromic and syndromic forms of PM. Here, we performed a clinical and genetic analysis using six consanguineous families ascertained from different regions of Tunisia and affected with non-syndromic PM that segregates as an autosomal recessive trait. To identify the disease-causing defect in these families, we first analysed MFRP gene, then some candidate genes (CHX10, OPA1, MITF, SOX2, CRYBB1-3 and CRYBA4) and loci (MCOP1, NNO1 and NNO2) previously implicated in different forms of microphthalmia. After exclusion of these genes and loci, we performed a genome-wide scan using a high density single nucleotide polymorphism (SNP) array 50 K in a large consanguineous pedigree. SNP genotyping revealed eight homozygous candidate regions on chromosomes 1, 2, 3, 6, 15, 17 and 21. Linkage analysis with additional microsatellite markers only retained the 2q37.1 region with a maximum LOD score of 8.85 obtained for D2S2344 at theta = 0.00. Further investigations are compatible for linkage of four more families to this region with a refined critical interval of 2.35 Mb. The screening of five candidate genes SAG, PDE6D, CHRND, CHRNG and IRK13 did not reveal any disease-causing mutation.
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An autosomal recessive syndrome of severe mental retardation, cataract, coloboma and kyphosis maps to the pericentromeric region of chromosome 4. Eur J Hum Genet 2008; 17:125-8. [PMID: 18781183 DOI: 10.1038/ejhg.2008.159] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
We report on three siblings with a novel mental retardation (MR) syndrome who were born to distantly related Iranian parents. The clinical problems comprised severe MR, cataracts with onset in late adolescence, kyphosis, contractures of large joints, bulbous nose with broad nasal bridge, and thick lips. Two patients also had uni- or bilateral iris coloboma. Linkage analysis revealed a single 10.4 Mb interval of homozygosity with significant LOD score in the pericentromeric region of chromosome 4 flanked by SNPs rs728293 (4p12) and rs1105434 (4q12). This interval contains more than 40 genes, none of which has been implicated in MR so far. The identification of the causative gene defect for this syndrome will provide new insights into the development of the brain and the eye.
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Kokkinopoulos I, Pearson R, MacNeil A, Dhomen N, MacLaren R, Ali R, Sowden J. Isolation and characterisation of neural progenitor cells from the adult Chx10orJ/orJ central neural retina. Mol Cell Neurosci 2008; 38:359-73. [DOI: 10.1016/j.mcn.2008.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2007] [Revised: 03/20/2008] [Accepted: 03/25/2008] [Indexed: 12/29/2022] Open
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Vsx2/Chx10 ensures the correct timing and magnitude of Hedgehog signaling in the mouse retina. Dev Biol 2008; 317:560-75. [PMID: 18417110 DOI: 10.1016/j.ydbio.2008.02.055] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2007] [Revised: 02/07/2008] [Accepted: 02/29/2008] [Indexed: 12/27/2022]
Abstract
Vertebrate retinal progenitor cells (RPCs) undergo a robust proliferative expansion to produce enough cells for the retina to form appropriately. Vsx2 (formerly Chx10), a homeodomain protein expressed in RPCs, is required for sufficient proliferation to occur. Sonic Hedgehog protein (SHH), secreted by retinal ganglion cells (RGCs), activates Hedgehog (Hh) signaling in RPCs and is also required for sufficient proliferation to occur. Therefore, we sought to determine if reduced Hh signaling is a contributing factor to the proliferation changes that occur in the absence of Vsx2. To do this, we examined Shh expression and Hh signaling activity in the homozygous ocular retardation J (orJ) mouse, which harbors a recessive null allele in the Vsx2 gene. We found that Shh expression and Hh signaling activity are delayed during early retinal development in orJ mice and this correlates with a delay in the onset of RGC differentiation. At birth, reduced expression of genes regulated by Hh signaling was observed despite the production of SHH ligand. orJ RPCs respond to pre-processed recombinant SHH ligand (SHH-N) in explant culture as evidenced by increased proliferation and expression of Hh target genes. Interestingly, proliferation in the orJ retina is further inhibited by cyclopamine, an antagonist of Hh signaling. Our results suggest that reduced Hh signaling contributes to the reduced level of RPC proliferation in the orJ retina, thereby revealing a role for Vsx2 in mediating mitogen signaling.
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Faiyaz-Ul-Haque M, Zaidi SHE, Al-Mureikhi MS, Peltekova I, Tsui LC, Teebi AS. Mutations in the CHX10 gene in non-syndromic microphthalmia/anophthalmia patients from Qatar. Clin Genet 2007; 72:164-6. [PMID: 17661825 DOI: 10.1111/j.1399-0004.2007.00846.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Localization of a novel gene for congenital nonsyndromic simple microphthalmia to chromosome 2q11-14. Hum Genet 2007; 122:589-93. [PMID: 17924146 DOI: 10.1007/s00439-007-0435-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2007] [Accepted: 09/25/2007] [Indexed: 10/22/2022]
Abstract
Microphthalmia is a clinically and genetically heterogeneous disorder of eye development. The genetic basis of nonsyndromic microphthalmia is not yet fully understood. Previous studies indicated that disease pedigrees from different genetic backgrounds could be attributed to completely different gene loci. To investigate the etiology in a large autosomal-dominant inherited simple microphthalmia (nanophthalmia) pedigree, which is the first genetically analyzed Chinese microphthalmia pedigree, we performed a whole-genome scan using 382 micro-satellite DNA markers after the exclusion of reported candidates associated with microphthalmia. Strong evidence indicated that microphthalmia in this family was mapped to an unreported new locus on chromosome 2q. A significantly positive two-point LOD score was obtained with a maximum 3.290 at a recombination fraction of 0.00 for marker D2S2265. Subsequent haplotype analysis and recombination data further confined the disease-causing gene to a 15-cM interval between D2S1890 and D2S347 on 2q11-14. Our results further underlined the degree of heterogeneity in microphthalmia from Chinese background and localized a novel gene which regulates eye embryogenesis.
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Ragge NK, Subak-Sharpe ID, Collin JRO. A practical guide to the management of anophthalmia and microphthalmia. Eye (Lond) 2007; 21:1290-300. [PMID: 17914432 DOI: 10.1038/sj.eye.6702858] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Congenital anophthalmia and microphthalmia are rare developmental defects of the globe. They often arise in conjunction with other ocular defects such as coloboma and orbital cyst. They may also be part of more generalised syndromes, such as CHARGE syndrome. Anophthalmia, microphthalmia, and coloboma are likely to be caused by disturbances of the morphogenetic pathway that controls eye development, either as a result of primary genetic defect, or external gestational factors, including infection or drugs that can influence the smooth processes of morphogenesis. The ophthalmologist is often the primary carer for children with anophthalmia and microphthalmia, and as such can coordinate the multidisciplinary input needed to offer optimal care for these individuals, including vision and family support services. They are able to assess the vision and maximise the visual potential of the child and they can also ensure that the cosmetic and social impact of anophthalmia or microphthalmia is minimised by starting socket expansion or referring to a specialist oculoplastics and prosthetics unit. A coordinated approach with paediatrics is necessary to manage any associated conditions. Genetic diagnosis and investigations can greatly assist in providing a diagnosis and informed genetic counselling.
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Affiliation(s)
- N K Ragge
- Department of Ophthalmology, Moorfields Eye Hospital, London, UK.
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Clark AM, Yun S, Veien ES, Wu YY, Chow RL, Dorsky RI, Levine EM. Negative regulation of Vsx1 by its paralog Chx10/Vsx2 is conserved in the vertebrate retina. Brain Res 2007; 1192:99-113. [PMID: 17919464 DOI: 10.1016/j.brainres.2007.06.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2007] [Revised: 06/08/2007] [Accepted: 06/13/2007] [Indexed: 01/03/2023]
Abstract
Chx10/Vsx2 and Vsx1 are the only Paired-like CVC (Prd-L:CVC) homeobox genes in the mouse genome. Both are expressed in the retina and have important but distinct roles in retinal development. Mutations in Chx10/Vsx2 cause reduced retinal progenitor cell (RPC) proliferation and an absence of bipolar cells, while mutations in Vsx1 impair differentiation of cone bipolar cells. Given their structural similarities and importance in retinal development, we sought to determine if a regulatory interaction exists between these genes and whether inactivation of both genes blocks initiation of retinal development. We found that Chx10/Vsx2 binds to a specific sequence in the Vsx1 5'-intergenic region and represses the activity of a luciferase reporter under the control of the Vsx1 promoter. This is consistent with our observation that there is an inverse relationship between the levels of Chx10/Vsx2 and Vsx1 immunostaining within the bipolar cell class. Furthermore, Vsx1 mRNA is upregulated in the RPCs of Chx10/Vsx2 deficient mice and zebrafish embryos injected with a chx10/vsx2 morpholino. In mice deficient for both Chx10/Vsx2 and Vsx1 and zebrafish embryos co-injected with chx10/Vsx2 and vsx1 morpholinos, the changes in embryonic retinal development and marker expression are similar in magnitude to embryos with Chx10/Vsx2 loss of function only. From these studies, we propose that Vsx1 is a direct target of Chx10/Vsx2-mediated transcriptional repression. Although Vsx1 mRNA is upregulated in Chx10/Vsx2 deficient RPCs, Vsx1 does not genetically compensate for loss of Chx10/Vsx2, demonstrating that Prd-L:CVC genes, although important, are not absolutely required to initiate retinal development.
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Affiliation(s)
- Anna M Clark
- Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
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Golzio C, Martinovic-Bouriel J, Thomas S, Mougou-Zrelli S, Grattagliano-Bessieres B, Bonniere M, Delahaye S, Munnich A, Encha-Razavi F, Lyonnet S, Vekemans M, Attie-Bitach T, Etchevers HC. Matthew-Wood syndrome is caused by truncating mutations in the retinol-binding protein receptor gene STRA6. Am J Hum Genet 2007; 80:1179-87. [PMID: 17503335 PMCID: PMC1867105 DOI: 10.1086/518177] [Citation(s) in RCA: 148] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 03/16/2007] [Indexed: 01/01/2023] Open
Abstract
Retinoic acid (RA) is a potent teratogen in all vertebrates when tight homeostatic controls on its endogenous dose, location, or timing are perturbed during early embryogenesis. STRA6 encodes an integral cell-membrane protein that favors RA uptake from soluble retinol-binding protein; its transcription is directly regulated by RA levels. Molecular analysis of STRA6 was undertaken in two human fetuses from consanguineous families we previously described with Matthew-Wood syndrome in a context of severe microphthalmia, pulmonary agenesis, bilateral diaphragmatic eventration, duodenal stenosis, pancreatic malformations, and intrauterine growth retardation. The fetuses had either a homozygous insertion/deletion in exon 2 or a homozygous insertion in exon 7 predicting a premature stop codon in STRA6 transcripts. Five other fetuses presenting at least one of the two major signs of clinical anophthalmia or pulmonary hypoplasia with at least one of the two associated signs of diaphragmatic closure defect or cardiopathy had no STRA6 mutations. These findings suggest a molecular basis for the prenatal manifestations of Matthew-Wood syndrome and suggest that phenotypic overlap with other associations may be due to genetic heterogeneity of elements common to the RA- and fibroblast growth factor-signaling cascades.
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Pasutto F, Sticht H, Hammersen G, Gillessen-Kaesbach G, Fitzpatrick DR, Nürnberg G, Brasch F, Schirmer-Zimmermann H, Tolmie JL, Chitayat D, Houge G, Fernández-Martínez L, Keating S, Mortier G, Hennekam RCM, von der Wense A, Slavotinek A, Meinecke P, Bitoun P, Becker C, Nürnberg P, Reis A, Rauch A. Mutations in STRA6 cause a broad spectrum of malformations including anophthalmia, congenital heart defects, diaphragmatic hernia, alveolar capillary dysplasia, lung hypoplasia, and mental retardation. Am J Hum Genet 2007; 80:550-60. [PMID: 17273977 PMCID: PMC1821097 DOI: 10.1086/512203] [Citation(s) in RCA: 249] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2006] [Accepted: 01/02/2007] [Indexed: 11/04/2022] Open
Abstract
We observed two unrelated consanguineous families with malformation syndromes sharing anophthalmia and distinct eyebrows as common signs, but differing for alveolar capillary dysplasia or complex congenital heart defect in one and diaphragmatic hernia in the other family. Homozygosity mapping revealed linkage to a common locus on chromosome 15, and pathogenic homozygous mutations were identified in STRA6, a member of a large group of "stimulated by retinoic acid" genes encoding novel transmembrane proteins, transcription factors, and secreted signaling molecules or proteins of largely unknown function. Subsequently, homozygous STRA6 mutations were also demonstrated in 3 of 13 patients chosen on the basis of significant phenotypic overlap to the original cases. While a homozygous deletion generating a premature stop codon (p.G50AfsX22) led to absence of the immunoreactive protein in patient's fibroblast culture, structural analysis of three missense mutations (P90L, P293L, and T321P) suggested significant effects on the geometry of the loops connecting the transmembrane helices of STRA6. Two further variations in the C-terminus (T644M and R655C) alter specific functional sites, an SH2-binding motif and a phosphorylation site, respectively. STRA6 mutations thus define a pleiotropic malformation syndrome representing the first human phenotype associated with mutations in a gene from the "STRA" group.
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Affiliation(s)
- Francesca Pasutto
- Institute of Human Genetics, Friedrich Alexander University Erlangen Nuremberg, Erlangen, Germany
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Nolen LD, Amor D, Haywood A, St Heaps L, Willcock C, Mihelec M, Tam P, Billson F, Grigg J, Peters G, Jamieson RV. Deletion at 14q22-23 indicates a contiguous gene syndrome comprising anophthalmia, pituitary hypoplasia, and ear anomalies. Am J Med Genet A 2006; 140:1711-8. [PMID: 16835935 DOI: 10.1002/ajmg.a.31335] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Anophthalmia and pituitary gland hypoplasia are both debilitating conditions where the underlying genetic defect is unknown in the majority of cases. We identified a patient with bilateral anophthalmia and absence of the optic nerves, chiasm and tracts, as well as pituitary gland hypoplasia and ear anomalies with a de novo apparently balanced chromosomal translocation, 46,XY,t(3;14)(q28;q23.2). Translocation breakpoint analysis using FISH and high-resolution microarray comparative genomic hybridization (CGH) has identified a 9.66 Mb deleted region on the long arm of chromosome 14 which includes the genes BMP4, OTX2, RTN1, SIX6, SIX1, and SIX4. Three other patients with interstitial deletions involving 14q22-23 have been described, all with bilateral anophthalmia, pituitary abnormalities, ear anomalies, and a facial phenotype similar to our patient. OTX2 is involved in ocular developmental defects, and the severity of the ocular phenotype in our patient and the other 14q22-23 deletion patients, suggests this genomic region harbors other gene/s involved in ocular development. BMP4 haploinsufficiency is predicted to contribute to the ocular phenotype on the basis of its expression pattern and observed murine mutant phenotypes. In addition, deletion of BMP4 and SIX6 is likely to contribute to the abnormal pituitary development, and SIX1 deletion may contribute to the ear and other craniofacial features. This indicates that contiguous gene deletion may contribute to the phenotypic features in the 14q22-23 deletion patients.
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Affiliation(s)
- Leisha D Nolen
- Eye Genetics Research Group, Children's Medical Research Institute, The Children's Hospital at Westmead and Save Sight Institute, Sydney, New South Wales, Australia
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Zenteno JC, Gascon-Guzman G, Tovilla-Canales JL. Bilateral anophthalmia and brain malformations caused by a 20-bp deletion in the SOX2 gene. Clin Genet 2006; 68:564-6. [PMID: 16283891 DOI: 10.1111/j.1399-0004.2005.00518.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Dhomen NS, Balaggan KS, Pearson RA, Bainbridge JW, Levine EM, Ali RR, Sowden JC. Absence of chx10 causes neural progenitors to persist in the adult retina. Invest Ophthalmol Vis Sci 2006; 47:386-96. [PMID: 16384989 PMCID: PMC2423807 DOI: 10.1167/iovs.05-0428] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
PURPOSE Mutation of the Chx10 homeobox gene in mice and humans causes congenital blindness and microphthalmia (small eyes). This study used Chx10-/- (ocular retardation) mice to investigate how lack of Chx10 affects progenitor/stem cell behavior in the retina and ciliary epithelium (CE). METHODS The distribution of mitotic retinal progenitor cells (RPCs) during embryonic development was analyzed using phosphohistone 3 (H3)-labeling. DNA flow cytometry was used to measure DNA content. The distribution and phenotype of dividing cells in the postnatal retina and CE was analyzed by incorporation of the thymidine analogue BrdU and immunohistochemistry. RESULTS The Chx10-/- embryonic retina maintained a constantly sized population of mitotic RPCs during development, causing the mitotic index to increase markedly over time compared with the wild type. Also, the proportion of cells in the G1 phase of the cell cycle was increased compared with the wild type. Of interest, division of RPC-like cells with neurogenic properties persisted in the adult Chx10-/- retina. Colabeling for BrdU and the neural progenitor marker nestin or the neuronal markers beta3-tubulin, syntaxin, and VC1.1 showed that new amacrine-like neurons developed in the adult central retina. By contrast, cells with these characteristics were not observed in the mature wild-type retina. In the mature CE, BrdU-positive cells were observed in both wild-type and Chx10-/- mice. However, neurogenesis from this cell population was not evident. CONCLUSIONS Without Chx10, proliferative expansion of the embryonic RPC pool is markedly reduced. In the adult retina, lack of Chx10 results in a population of dividing neural progenitor cells that persist and produce new neurons in the central retina.
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Affiliation(s)
| | - Kam S. Balaggan
- Institute of Ophthalmology, University College of London, London, United Kingdom; and the
| | | | - James W. Bainbridge
- Institute of Ophthalmology, University College of London, London, United Kingdom; and the
| | - Edward M. Levine
- John A. Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Robin R. Ali
- Institute of Ophthalmology, University College of London, London, United Kingdom; and the
| | - Jane C. Sowden
- From the Developmental Biology Unit, Institute of Child Health, and the
- Corresponding author: Jane C. Sowden, Developmental Biology Unit, Institute of Child Health, UCL, 30 Guilford Street, London WC1N 1EH, UK;
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Fitzpatrick DR, van Heyningen V. Developmental eye disorders. Curr Opin Genet Dev 2005; 15:348-53. [PMID: 15917212 DOI: 10.1016/j.gde.2005.04.013] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2005] [Accepted: 04/14/2005] [Indexed: 11/19/2022]
Abstract
In developed countries, malformations of the eye are among the most common causes of serious visual impairment in newborns. The identification of pathogenic mutations in autosomal and X-linked transcription factors has advanced our understanding of the critical stages in human eye development and has begun to explain some unusual inheritance characteristics of these disorders. The functional characterisation of these genes in model organisms has prompted reinvestigation of affected individuals to identify previously unrecognized but consistent extra-ocular malformations. This dialogue between clinical genetics and basic developmental biology provides a paradigm to enhance our understanding of many critical developmental processes in human embryogenesis.
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Affiliation(s)
- David R Fitzpatrick
- Medical Research Council, Human Genetics Unit, Western General Hospital, Edinburgh EH4 2XU, UK
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Ragge NK, Salt A, Collin JRO, Michalski A, Farndon PA. Gorlin syndrome: the PTCH gene links ocular developmental defects and tumour formation. Br J Ophthalmol 2005; 89:988-91. [PMID: 16024850 PMCID: PMC1772759 DOI: 10.1136/bjo.2004.061390] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2004] [Indexed: 11/04/2022]
Abstract
AIM To identify a gene linking microphthalmia with cyst with early onset medulloblastoma. METHODS Mutation analysis of the PTCH gene. RESULTS A mutation in exon 10 of the PTCH gene was identified, confirming a diagnosis of Gorlin syndrome. CONCLUSIONS This is the first genetically identified mutation giving rise to microphthalmia with cyst and provides a valuable link in the eye developmental gene pathway.
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Affiliation(s)
- N K Ragge
- Department of Human Anatomy and Genetics, South Parks Road, Oxford OX1 3QX, UK.
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Manson FDC, Trump D, Read AP, Black GCM. Inherited eye disease: cause and late effect. Trends Mol Med 2005; 11:449-55. [PMID: 16153893 DOI: 10.1016/j.molmed.2005.08.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 07/12/2005] [Accepted: 08/16/2005] [Indexed: 01/14/2023]
Abstract
Molecular genetics has provided relatively few insights into late-onset eye disorders, but epidemiological data indicate that genetic factors are important in some late-onset eye disorders that cause major health burdens. Much clinical genetic research is based on the belief that developmental and late-onset disorders are not necessarily the result of defects in different genes, but are often caused by different mutations in the same collection of genes. Thus, mutations that either abolish or radically change gene function might cause early-onset disorders, whereas more-subtle changes in gene expression might underlie late-onset diseases. We present arguments and examples that indicate that this principle might be a fruitful guide to investigating the causes of late-onset eye disorders.
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Affiliation(s)
- Forbes D C Manson
- Academic Unit of Eye and Vision Science, Manchester Royal Eye Hospital, School of Medicine, University of Manchester, Oxford Road, Manchester M13 9WH, UK
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