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Sakti DH, Cornish EE, Ali H, Retsas S, Raza M, Saakova N, Carvalho LS, Nash BM, Jamieson RV, Grigg JR. Natural history and biomarkers of KCNV2-associated retinopathy. Clin Exp Ophthalmol 2024; 52:528-544. [PMID: 38443311 DOI: 10.1111/ceo.14373] [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: 09/28/2023] [Revised: 01/31/2024] [Accepted: 02/14/2024] [Indexed: 03/07/2024]
Abstract
BACKGROUND KCNV2-associated retinopathy is an autosomal recessive inherited retinal disease classically named cone dystrophy with supernormal rod response (CDSRR). This study aims to identify the best biomarker for evaluating the condition. METHODS A retrospective review of eight patients from seven families with genetically confirmed KCNV2-associated retinopathy was performed. The best corrected visual acuity (BCVA), full-field electroretinogram (ffERG), pattern ERG (pERG), fundus imaging: retinal photograph and fundus autofluorescence (FAF), and optical coherence tomography (OCT) were analysed. RESULTS There was a disproportionate increase in b-wave amplitude with a relatively small light intensity increase, especially between the two dimmest stimuli of DA 0.002 and 0.01 (-2.7 and -2.0 log cd.s/m2). The a-wave amplitude was normal. The a-wave peak time was delayed in all stimuli. The b-wave peak time was delayed compared to normal, but the gap tightened as intensity increased. The b:a wave ratio was above or at the upper limit for the reference values. FAF bull's eye maculopathy pattern was prominent and variable foveal disruption on OCT was apparent in all patients. Legal blindness was reached before the age of 25. CONCLUSIONS We identified three potential electrophysiology biomarkers to assist in evaluating future therapies: the disproportionate b-wave amplitude jump, delayed a-wave and b-wave peak time, and the higher than normal b:a wave ratio. Any of these biomarkers found with photoreceptor ellipsoid zone foveal-perifoveal disruption should prompt consideration for KCNV2 retinopathy. The BCVA natural history data suggests the probable optimum therapeutic window in the first three decades of life.
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Affiliation(s)
- Dhimas H Sakti
- Save Sight Institute, University of Sydney, New South Wales, Australia
- Department of Ophthalmology, Faculty of Medicine, Public Health, and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Elisa E Cornish
- Save Sight Institute, University of Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Haipha Ali
- Save Sight Institute, University of Sydney, New South Wales, Australia
| | - Stephanie Retsas
- Save Sight Institute, University of Sydney, New South Wales, Australia
| | - Marium Raza
- Save Sight Institute, University of Sydney, New South Wales, Australia
| | - Nonna Saakova
- Save Sight Institute, University of Sydney, New South Wales, Australia
| | - Livia S Carvalho
- Centre for Ophthalmology and Visual Sciences, Lions Eye Institute, The University of Western Australia, Nedlands, Australia
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Melbourne, Australia
| | - Benjamin M Nash
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - Robyn V Jamieson
- Save Sight Institute, University of Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
| | - John R Grigg
- Save Sight Institute, University of Sydney, New South Wales, Australia
- Eye Genetics Research Unit, Children's Medical Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
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Corradetti G, Verma A, Tojjar J, Almidani L, Oncel D, Emamverdi M, Bradley A, Lindenberg S, Nittala MG, Sadda SR. Retinal Imaging Findings in Inherited Retinal Diseases. J Clin Med 2024; 13:2079. [PMID: 38610844 PMCID: PMC11012835 DOI: 10.3390/jcm13072079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2024] [Revised: 03/19/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Inherited retinal diseases (IRDs) represent one of the major causes of progressive and irreversible vision loss in the working-age population. Over the last few decades, advances in retinal imaging have allowed for an improvement in the phenotypic characterization of this group of diseases and have facilitated phenotype-to-genotype correlation studies. As a result, the number of clinical trials targeting IRDs has steadily increased, and commensurate to this, the need for novel reproducible outcome measures and endpoints has grown. This review aims to summarize and describe the clinical presentation, characteristic imaging findings, and imaging endpoint measures that are being used in clinical research on IRDs. For the purpose of this review, IRDs have been divided into four categories: (1) panretinal pigmentary retinopathies affecting rods or cones; (2) macular dystrophies; (3) stationary conditions; (4) hereditary vitreoretinopathies.
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Affiliation(s)
- Giulia Corradetti
- Doheny Eye Institute, Pasadena, CA 91103, USA (J.T.); (L.A.)
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Aditya Verma
- Doheny Eye Institute, Pasadena, CA 91103, USA (J.T.); (L.A.)
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202, USA
| | - Jasaman Tojjar
- Doheny Eye Institute, Pasadena, CA 91103, USA (J.T.); (L.A.)
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
| | - Louay Almidani
- Doheny Eye Institute, Pasadena, CA 91103, USA (J.T.); (L.A.)
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Deniz Oncel
- Doheny Eye Institute, Pasadena, CA 91103, USA (J.T.); (L.A.)
- Stritch School of Medicine, Loyola University Chicago, Chicago, IL 60153, USA
| | - Mehdi Emamverdi
- Doheny Eye Institute, Pasadena, CA 91103, USA (J.T.); (L.A.)
| | - Alec Bradley
- Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, KY 40202, USA
| | | | | | - SriniVas R. Sadda
- Doheny Eye Institute, Pasadena, CA 91103, USA (J.T.); (L.A.)
- Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, CA 90095, USA
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Gulati S, Palczewski K. Structural view of G protein-coupled receptor signaling in the retinal rod outer segment. Trends Biochem Sci 2023; 48:172-186. [PMID: 36163145 PMCID: PMC9868064 DOI: 10.1016/j.tibs.2022.08.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 01/26/2023]
Abstract
Visual phototransduction is the most extensively studied G protein-coupled receptor (GPCR) signaling pathway because of its quantifiable stimulus, non-redundancy of genes, and immense importance in vision. We summarize recent discoveries that have advanced our understanding of rod outer segment (ROS) morphology and the pathological basis of retinal diseases. We have combined recently published cryo-electron tomography (cryo-ET) data on the ROS with structural knowledge on individual proteins to define the precise spatial limitations under which phototransduction occurs. Although hypothetical, the reconstruction of the rod phototransduction system highlights the potential roles of phosphodiesterase 6 (PDE6) and guanylate cyclases (GCs) in maintaining the spacing between ROS discs, suggesting a plausible mechanism by which intrinsic optical signals are generated in the retina.
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Affiliation(s)
| | - Krzysztof Palczewski
- Gavin Herbert Eye Institute and the Department of Ophthalmology, Center for Translational Vision Research, Department of Physiology and Biophysics, Department of Chemistry, Molecular Biology, and Biochemistry, University of California Irvine, 850 Health Sciences Road, Irvine, CA 92697-4375, USA.
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4
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Al-Khannaq M, Lytton J. Regulation of K +-Dependent Na +/Ca 2+-Exchangers (NCKX). Int J Mol Sci 2022; 24:ijms24010598. [PMID: 36614039 PMCID: PMC9820825 DOI: 10.3390/ijms24010598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 12/23/2022] [Accepted: 12/24/2022] [Indexed: 12/31/2022] Open
Abstract
Potassium-dependent sodium-calcium exchangers (NCKX) have emerged as key determinants of calcium (Ca2+) signaling and homeostasis, especially in environments where ion concentrations undergo large changes, such as excitatory cells and transport epithelia. The regulation of NCKX transporters enables them to respond to the changing cellular environment thereby helping to shape the extent and kinetics of Ca2+ signals. This review examines the current knowledge of the different ways in which NCKX activity can be modulated. These include (i) cellular and dynamic subcellular location (ii); changes in protein expression mediated at the gene, transcript, or protein level (iii); genetic changes resulting in altered protein structure or expression (iv); regulation via changes in substrate concentration (v); and post-translational modification, partner protein interactions, and allosteric regulation. Detailed mechanistic understanding of NCKX regulation is an emerging area of research with the potential to provide important new insights into transporter function, the control of Ca2+ signals, and possible interventions for dysregulated Ca2+ homeostasis.
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Millo T, Rivera A, Obolensky A, Marks-Ohana D, Xu M, Li Y, Wilhelm E, Gopalakrishnan P, Gross M, Rosin B, Hanany M, Webster A, Tracewska AM, Koenekoop RK, Chen R, Arno G, Schueler-Furman O, Roosing S, Banin E, Sharon D. Identification of autosomal recessive novel genes and retinal phenotypes in members of the solute carrier (SLC) superfamily. Genet Med 2022; 24:1523-1535. [PMID: 35486108 DOI: 10.1016/j.gim.2022.03.020] [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: 09/28/2021] [Revised: 03/20/2022] [Accepted: 03/28/2022] [Indexed: 12/01/2022] Open
Abstract
PURPOSE This study aimed to investigate the clinical and genetic aspects of solute carrier (SLC) genes in inherited retinal diseases (IRDs). METHODS Exome sequencing data were filtered to identify pathogenic variants in SLC genes. Analysis of transcript and protein expression was performed on fibroblast cell lines and retinal sections. RESULTS Comprehensive analysis of 433 SLC genes in 913 exome sequencing IRD samples revealed homozygous pathogenic variants in 6 SLC genes, including 2 candidate novel genes, which were 2 variants in SLC66A1, causing autosomal recessive retinitis pigmentosa (ARRP), and a variant in SLC39A12, causing autosomal recessive mild widespread retinal degeneration with marked macular involvement. In addition, we present 4 families with ARRP and homozygous null variants in SLC37A3 that were previously suggested to cause retinitis pigmentosa, 2 of which cause exon skipping. The recently reported SLC4A7- c.2007dup variant was found in 2 patients with ARRP resulting in the absence of protein. Finally, variants in SLC24A1 were found in 4 individuals with either ARRP or congenital stationary night blindness. CONCLUSION We report on SLC66A1 and SLC39A12 as candidate novel IRD genes, establish SLC37A3 pathogenicity, and provide further evidence of SLC4A7 as IRD genes. We extend the phenotypic spectrum of SLC24A1 and suggest that its ARRP phenotype may be more common than previously reported.
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Affiliation(s)
- Talya Millo
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Antonio Rivera
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Alexey Obolensky
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Devora Marks-Ohana
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mingchu Xu
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Yumei Li
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Enosh Wilhelm
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Prakadeeswari Gopalakrishnan
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Menachem Gross
- Department of Otolaryngology/Head and Neck Surgery, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Boris Rosin
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mor Hanany
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Andrew Webster
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom
| | - Anna Maria Tracewska
- Łukasiewicz Research Network - PORT Polish Center for Technology Development, Stabłowicka, Wrocław, Poland
| | - Robert K Koenekoop
- Department of Paediatric surgery, Human Genetics and Ophthalmology, Montreal Children's Hospital, McGill University Health Centre, Montreal, Quebec, Canada
| | - Rui Chen
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX
| | - Gavin Arno
- University College London, Institute of Ophthalmology, London, United Kingdom; Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom
| | - Ora Schueler-Furman
- Department of Microbiology and Molecular Genetics, Institute of Medical Research Israel-Canada, Faculty of Medicine, The Hebrew University of Jerusalem, Israel
| | - Susanne Roosing
- Department of Human Genetics, Radboudumc, Nijmegen, The Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboudumc, Nijmegen, The Netherlands
| | - Eyal Banin
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
| | - Dror Sharon
- Division of Ophthalmology, Hadassah University Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel.
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Marques JP, Chaves J. SLC24A1-Associated Congenital Stationary Night Blindness in a Woman With an Abnormal Fundus. JAMA Ophthalmol 2022; 140:e216343. [PMID: 35446361 DOI: 10.1001/jamaophthalmol.2021.6343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- João Pedro Marques
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal.,University Clinic of Ophthalmology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Clinical Academic Center of Coimbra, Coimbra, Portugal
| | - João Chaves
- Ophthalmology Unit, Centro Hospitalar e Universitário de Coimbra, Coimbra, Portugal
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7
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Biswas P, Villanueva AL, Soto-Hermida A, Duncan JL, Matsui H, Borooah S, Kurmanov B, Richard G, Khan SY, Branham K, Huang B, Suk J, Bakall B, Goldberg JL, Gabriel L, Khan NW, Raghavendra PB, Zhou J, Devalaraja S, Huynh A, Alapati A, Zawaydeh Q, Weleber RG, Heckenlively JR, Hejtmancik JF, Riazuddin S, Sieving PA, Riazuddin SA, Frazer KA, Ayyagari R. Deciphering the genetic architecture and ethnographic distribution of IRD in three ethnic populations by whole genome sequence analysis. PLoS Genet 2021; 17:e1009848. [PMID: 34662339 PMCID: PMC8589175 DOI: 10.1371/journal.pgen.1009848] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 11/12/2021] [Accepted: 09/29/2021] [Indexed: 12/12/2022] Open
Abstract
Patients with inherited retinal dystrophies (IRDs) were recruited from two understudied populations: Mexico and Pakistan as well as a third well-studied population of European Americans to define the genetic architecture of IRD by performing whole-genome sequencing (WGS). Whole-genome analysis was performed on 409 individuals from 108 unrelated pedigrees with IRDs. All patients underwent an ophthalmic evaluation to establish the retinal phenotype. Although the 108 pedigrees in this study had previously been examined for mutations in known IRD genes using a wide range of methodologies including targeted gene(s) or mutation(s) screening, linkage analysis and exome sequencing, the gene mutations responsible for IRD in these 108 pedigrees were not determined. WGS was performed on these pedigrees using Illumina X10 at a minimum of 30X depth. The sequence reads were mapped against hg19 followed by variant calling using GATK. The genome variants were annotated using SnpEff, PolyPhen2, and CADD score; the structural variants (SVs) were called using GenomeSTRiP and LUMPY. We identified potential causative sequence alterations in 61 pedigrees (57%), including 39 novel and 54 reported variants in IRD genes. For 57 of these pedigrees the observed genotype was consistent with the initial clinical diagnosis, the remaining 4 had the clinical diagnosis reclassified based on our findings. In seven pedigrees (12%) we observed atypical causal variants, i.e. unexpected genotype(s), including 4 pedigrees with causal variants in more than one IRD gene within all affected family members, one pedigree with intrafamilial genetic heterogeneity (different affected family members carrying causal variants in different IRD genes), one pedigree carrying a dominant causative variant present in pseudo-recessive form due to consanguinity and one pedigree with a de-novo variant in the affected family member. Combined atypical and large structural variants contributed to about 20% of cases. Among the novel mutations, 75% were detected in Mexican and 50% found in European American pedigrees and have not been reported in any other population while only 20% were detected in Pakistani pedigrees and were not previously reported. The remaining novel IRD causative variants were listed in gnomAD but were found to be very rare and population specific. Mutations in known IRD associated genes contributed to pathology in 63% Mexican, 60% Pakistani and 45% European American pedigrees analyzed. Overall, contribution of known IRD gene variants to disease pathology in these three populations was similar to that observed in other populations worldwide. This study revealed a spectrum of mutations contributing to IRD in three populations, identified a large proportion of novel potentially causative variants that are specific to the corresponding population or not reported in gnomAD and shed light on the genetic architecture of IRD in these diverse global populations. The study was performed to identify the underlying cause of inherited retinal degeneration (IRD) in 409 individuals from 108 families. Primarily, these families were recruited from three different geographic regions: Mexico, Pakistan and European Americans from the United States. Blood samples were collected from all individuals for genome analysis. This analysis detected causative variants in 61 out of the 108 pedigrees. A total of 93 gene variants were found in the 61 families. Among these, 54 were previously reported as causative variants and the remaining 39 have not been reported in IRD pedigrees. Interestingly, 54% of these novel variants were not listed in gnomAD. In addition to these findings, complex causative genotypes were observed in 20% of pedigrees. Overall, causative variants were detected in 63% Mexican, 60% Pakistani and 45% European American pedigrees. This study revealed the distribution of IRD causative variants in pedigrees with diverse ethnic and geographic backgrounds.
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Affiliation(s)
- Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
- School of Biotechnology, REVA University, Bengaluru, Karnataka, India
| | - Adda L. Villanueva
- Retina and Genomics Institute, Yucatán, México
- Laboratoire de Diagnostic Moleculaire, Hôpital Maisonneuve Rosemont, Montreal, Quebec, Canada
| | - Angel Soto-Hermida
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Jacque L. Duncan
- Ophthalmology, University of California San Francisco, San Francisco, California, United States of America
| | - Hiroko Matsui
- Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, United States of America
| | - Shyamanga Borooah
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Berzhan Kurmanov
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | | | - Shahid Y. Khan
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Kari Branham
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan, United States of America
| | - Bonnie Huang
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - John Suk
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Benjamin Bakall
- Ophthalmology, University of Arizona College of Medicine Phoenix, Phoenix, Arizona, United States of America
| | - Jeffrey L. Goldberg
- Byers Eye Institute, Stanford, Palo Alto, California, United States of America
| | - Luis Gabriel
- Genetics and Ophthalmology, Genelabor, Goiânia, Brazil
| | - Naheed W. Khan
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan, United States of America
| | - Pongali B. Raghavendra
- School of Biotechnology, REVA University, Bengaluru, Karnataka, India
- School of Regenerative Medicine, Manipal University, Bengaluru, Karnataka, India
| | - Jason Zhou
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Sindhu Devalaraja
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Andrew Huynh
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Akhila Alapati
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Qais Zawaydeh
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
| | - Richard G. Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, United States of America
| | - John R. Heckenlively
- Ophthalmology & Visual Science, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan, United States of America
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
| | - Paul A. Sieving
- National Eye Institute, Bethesda, Maryland, United States of America
- Ophthalmology & Vision Science, UC Davis Medical Center, California, United States of America
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- * E-mail: (RA); (KAF); (SAR)
| | - Kelly A. Frazer
- Institute for Genomic Medicine, University of California, San Diego, La Jolla, California, United States of America
- Department of Pediatrics, Rady Children’s Hospital, Division of Genome Information Sciences, San Diego, California, United States of America
- * E-mail: (RA); (KAF); (SAR)
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, California, United States of America
- * E-mail: (RA); (KAF); (SAR)
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Almutairi F, Almeshari N, Ahmad K, Magliyah MS, Schatz P. Congenital stationary night blindness: an update and review of the disease spectrum in Saudi Arabia. Acta Ophthalmol 2021; 99:581-591. [PMID: 33369259 DOI: 10.1111/aos.14693] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 11/03/2020] [Indexed: 12/22/2022]
Abstract
Congenital stationary night blindness (CSNB) is a group of rare, mainly stationary disorders of the retina, resulting from dysfunction of several specific and essential visual processing mechanisms. The inheritance is often recessive and as such, CSNB may be more common among populations with a high degree of consanguinity. Here, we present a topic update and a review of the clinical and molecular genetic spectrum of CSNB in Saudi Arabia. Since a major review article on CSNB in 2015, which described 17 genes underlying CSNB, an additional four genes have been incriminated in autosomal recessive CSNB: RIMS2, GNB3, GUCY2D and ABCA4. These have been associated with syndromic cone-rod synaptic disease, ON bipolar cell dysfunction with reduced cone sensitivity, CSNB with dysfunction of the phototransduction (Riggs type) and CSNB with cone-rod dystrophy, respectively. In Saudi Arabia, a total of 24 patients with CSNB were identified, using a combination of literature search and retrospective study of previously unpublished cases. Recessive mutations in TRPM1 and CABP4 accounted for the majority of cases (5 and 13 for each gene, respectively). These genes were associated with complete (cCSNB) and incomplete (icCSNB), respectively, and were associated with high myopia in the former and hyperopia in the latter. Four novel mutations were identified. For the first time, we describe the fundus albipunctatus in two patients from Saudi Arabia, caused by recessive mutation in RDH5 and RPE65, where the former in addition featured findings compatible with cone dystrophy. No cases were identified with any dominantly inherited CSNB.
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Affiliation(s)
- Faris Almutairi
- Vitreoretinal Division King Khaled Eye Specialist Hospital Riyadh Saudi Arabia
- King Khalid University Hospital Riyadh Saudi Arabia
| | | | - Khabir Ahmad
- Research Department King Khaled Eye Specialist Hospital Riyadh Saudi Arabia
| | - Moustafa S. Magliyah
- Vitreoretinal Division King Khaled Eye Specialist Hospital Riyadh Saudi Arabia
- Ophthalmology Department Prince Mohammed Medical City AlJouf Saudi Arabia
| | - Patrik Schatz
- Vitreoretinal Division King Khaled Eye Specialist Hospital Riyadh Saudi Arabia
- Department of Ophthalmology Clinical Sciences Skane University Hospital Lund University Lund Sweden
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9
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Kim HM, Joo K, Han J, Woo SJ. Clinical and Genetic Characteristics of Korean Congenital Stationary Night Blindness Patients. Genes (Basel) 2021; 12:genes12060789. [PMID: 34064005 PMCID: PMC8224030 DOI: 10.3390/genes12060789] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/11/2021] [Accepted: 05/18/2021] [Indexed: 01/27/2023] Open
Abstract
In this study, we investigated the clinical and genetic characteristics of 19 Korean patients with congenital stationary night blindness (CSNB) at two tertiary hospitals. Clinical evaluations, including fundus photography, spectral-domain optical coherence tomography, and electroretinography, were performed. Genetic analyses were conducted using targeted panel sequencing or whole exome sequencing. The median age was 5 (3–21) years at the initial examination, 2 (1–8) years at symptom onset, and 11 (5–28) years during the final visit. Genetic mutations were identified as CNGB1 and GNAT1 for the Riggs type (n = 2), TRPM1 and NYX for the complete type (n = 3), and CACNA1F (n = 14) for the incomplete type. Ten novel variants were identified, and best-corrected visual acuity (BCVA) and spherical equivalents (SE) were related to each type of CSNB. The Riggs and TRPM1 complete types presented mild myopia and good BCVA without strabismus and nystagmus, whereas the NYX complete and incomplete types showed mixed SE and poor BCVA with strabismus and nystagmus. This is the first case series of Korean patients with CSNB, and further studies with a larger number of subjects should be conducted to correlate the clinical and genetic aspects of CSNB.
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Affiliation(s)
- Hyeong-Min Kim
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea; (H.-M.K.); (K.J.)
| | - Kwangsic Joo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea; (H.-M.K.); (K.J.)
| | - Jinu Han
- Institute of Vision Research, Department of Ophthalmology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul 06273, Korea
- Correspondence: (J.H.); (S.-J.W.); Tel.: +82-2-2019-3445 (J.H.); +82-31-787-7377 (S.-J.W.); Fax: +82-2-3463-1049 (J.H.); +82-31-787-4057 (S.-J.W.)
| | - Se-Joon Woo
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seongnam 13620, Korea; (H.-M.K.); (K.J.)
- Correspondence: (J.H.); (S.-J.W.); Tel.: +82-2-2019-3445 (J.H.); +82-31-787-7377 (S.-J.W.); Fax: +82-2-3463-1049 (J.H.); +82-31-787-4057 (S.-J.W.)
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10
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Zang J, Neuhauss SCF. Biochemistry and physiology of zebrafish photoreceptors. Pflugers Arch 2021; 473:1569-1585. [PMID: 33598728 PMCID: PMC8370914 DOI: 10.1007/s00424-021-02528-z] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/25/2021] [Accepted: 01/28/2021] [Indexed: 02/06/2023]
Abstract
All vertebrates share a canonical retina with light-sensitive photoreceptors in the outer retina. These photoreceptors are of two kinds: rods and cones, adapted to low and bright light conditions, respectively. They both show a peculiar morphology, with long outer segments, comprised of ordered stacks of disc-shaped membranes. These discs host numerous proteins, many of which contribute to the visual transduction cascade. This pathway converts the light stimulus into a biological signal, ultimately modulating synaptic transmission. Recently, the zebrafish (Danio rerio) has gained popularity for studying the function of vertebrate photoreceptors. In this review, we introduce this model system and its contribution to our understanding of photoreception with a focus on the cone visual transduction cascade.
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Affiliation(s)
- Jingjing Zang
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrase 190, CH - 8057, Zürich, Switzerland
| | - Stephan C F Neuhauss
- Department of Molecular Life Sciences, University of Zurich, Winterthurerstrase 190, CH - 8057, Zürich, Switzerland.
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11
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Xu S, Coku A, Muraleedharan CK, Harajli A, Mishulin E, Dahabra C, Choi J, Garcia WJ, Webb K, Birch D, Goetz K, Li W. Mutation Screening in the miR-183/96/182 Cluster in Patients With Inherited Retinal Dystrophy. Front Cell Dev Biol 2020; 8:619641. [PMID: 33425925 PMCID: PMC7785829 DOI: 10.3389/fcell.2020.619641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/07/2020] [Indexed: 01/09/2023] Open
Abstract
Inherited retinal dystrophy (IRD) is a heterogenous blinding eye disease and affects more than 200,000 Americans and millions worldwide. By far, 270 protein-coding genes have been identified to cause IRD when defective. However, only one microRNA (miRNA), miR-204, has been reported to be responsible for IRD when a point-mutation occurs in its seed sequence. Previously, we identified that a conserved, polycistronic, paralogous miRNA cluster, the miR-183/96/182 cluster, is highly specifically expressed in all photoreceptors and other sensory organs; inactivation of this cluster in mice resulted in syndromic IRD with multi-sensory defects. We hypothesized that mutations in the miR-183/96/182 cluster in human cause IRD. To test this hypothesis, we perform mutation screening in the pre-miR-183, -96, -182 in >1000 peripheral blood DNA samples of patients with various forms of IRD. We identified six sequence variants, three in pre-miR-182 and three in pre-miR-96. These variants are in the pre-miRNA-182 or -96, but not in the mature miRNAs, and are unlikely to be the cause of the IRD in these patients. In spite of this, the nature and location of these sequence variants in the pre-miRNAs suggest that some may have impact on the biogenesis and maturation of miR-182 or miR-96 and potential roles in the susceptibility to diseases. Although reporting on negative results so far, our study established a system for mutation screening in the miR-183/96/182 cluster in human for a continued effort to unravel and provides deeper insight into the potential roles of miR-183/96/182 cluster in human diseases.
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Affiliation(s)
- Shunbin Xu
- Department of Ophthalmology, Visual and Anatomical Sciences, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Ardian Coku
- Department of Ophthalmology, Visual and Anatomical Sciences, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Chithra K Muraleedharan
- Department of Ophthalmology, Visual and Anatomical Sciences, School of Medicine, Wayne State University, Detroit, MI, United States
| | - Ali Harajli
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Eric Mishulin
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, United States
| | - Chafic Dahabra
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Joanne Choi
- Class of 2020, School of Medicine, Wayne State University, Detroit, MI, United States
| | - William J Garcia
- College of Natural Science, Michigan State University, East Lansing, MI, United States
| | - Kaylie Webb
- Retina Foundation of the Southwest, Dallas, TX, United States
| | - David Birch
- Retina Foundation of the Southwest, Dallas, TX, United States
| | - Kerry Goetz
- National Eye Institute, National Institutes of Health, Bethesda, MD, United States
| | - Weifeng Li
- Peking Union Medical College, Beijing, China
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12
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Hassan MT, Lytton J. Potassium-dependent sodium-calcium exchanger (NCKX) isoforms and neuronal function. Cell Calcium 2020; 86:102135. [DOI: 10.1016/j.ceca.2019.102135] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/25/2019] [Accepted: 11/26/2019] [Indexed: 12/16/2022]
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13
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Structure-function relationships of K +-dependent Na +/Ca 2+ exchangers (NCKX). Cell Calcium 2019; 86:102153. [PMID: 31927187 DOI: 10.1016/j.ceca.2019.102153] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 12/15/2019] [Accepted: 12/16/2019] [Indexed: 01/13/2023]
Abstract
K+-dependent Na+/Ca2+ exchanger proteins (NCKX1-5) of the SLC24 gene family play important roles in a wide range of biological processes including but not limited to rod and cone photoreceptor vision, olfaction, enamel formation and skin pigmentation. NCKX proteins are also widely expressed throughout the brain and NCKX2 and NCKX4 knockouts in mice have specific phenotypes. Here we review our work on structure-function relationships of NCKX proteins. We discuss membrane topology, domains critical to transport function, and residues critical to cation binding and transport function, all in the context of crystal structures that were obtained for the archaeal Na+/Ca2+ exchanger NCX_Mj.
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14
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Kubota D, Oishi N, Gocho K, Kikuchi S, Yamaki K, Igarashi T, Takahashi H, Ishida N, Iwata T, Mizota A, Kameya S. Novel homozygous in-frame deletion of GNAT1 gene causes golden appearance of fundus and reduced scotopic ERGs similar to that in Oguchi disease in Japanese family. Ophthalmic Genet 2019; 40:480-487. [PMID: 31696758 DOI: 10.1080/13816810.2019.1686159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Background: The GNAT1 gene encodes the alpha-subunit of transducin in rod photoreceptors and is an important part of the phototransduction cascade. Defects in GNAT1 are very rare but have been identified in autosomal dominant and recessive congenital stationary night blindness (CSNB) and autosomal recessive rod-cone dystrophy. The purpose of this study was to determine the phenotype-genotype relationship in a non-consanguineous Japanese family with a GNAT1 mutation.Methods: Detailed ophthalmic examinations were performed on the patients and their family members. Whole exome sequencing (WES) was applied to the DNA obtained from the family members. Sanger sequencing and co-segregation analyses were performed to identify the most likely pathogenic variant.Results: Two female (13- and 11-years) and one male (15-years) patients from a family had night blindness from their childhood. The fundus had a mild golden appearance regardless of the state of light- or dark-adaptation. Electroretinographic (ERG) analyses showed that the scotopic a-wave was extinguished, and the mixed rod-cone responses were severely reduced with an electronegative form in patients. The shapes of the dark-adapted ERGs were similar to those recorded from patients with Oguchi disease. We identified a homozygous in-frame deletion c.818_820delAGA, p.Lys273del in the GNAT1 gene. Variants were verified by Sanger sequencing and co-segregated with the disease in five members of the family.Conclusions: Our findings indicate that a recessive GNAT1 mutation found in this family could be the cause of the golden appearance of the fundus and negative ERGs with reduced a-waves, and nearly absent b-waves in the mixed rod-cone ERGs.
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Affiliation(s)
- Daiki Kubota
- Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Chiba, Japan
| | - Noriko Oishi
- Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Chiba, Japan
| | - Kiyoko Gocho
- Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Chiba, Japan
| | - Sachiko Kikuchi
- Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Chiba, Japan
| | - Kunihiko Yamaki
- Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Chiba, Japan
| | - Tsutomu Igarashi
- Department of Ophthalmology, Nippon Medical School, Tokyo, Japan
| | | | | | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, Tokyo, Japan
| | - Atsushi Mizota
- Department of Ophthalmology, Teikyo University School of Medicine, Tokyo, Japan
| | - Shuhei Kameya
- Department of Ophthalmology, Nippon Medical School Chiba Hokusoh Hospital, Inzai, Chiba, Japan
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15
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Liu HY, Huang J, Xiao H, Zhang MJ, Shi FF, Jiang YH, Du H, He Q, Wang ZY. Pseudodominant inheritance of autosomal recessive congenital stationary night blindness in one family with three co-segregating deleterious GRM6 variants identified by next-generation sequencing. Mol Genet Genomic Med 2019; 7:e952. [PMID: 31677249 PMCID: PMC6900388 DOI: 10.1002/mgg3.952] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 08/12/2019] [Accepted: 08/13/2019] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The congenital stationary night blindness (CSNB) affects the patients' dim light vision or dark adaption by impairing the normal function of retina. It is a clinically and genetically heterogeneous disorder and can be inherited in an X-linked, autosomal dominant or autosomal recessive pattern. Several genetic alterations to the genes involved in visual signal transduction of photoreceptors and/or bipolar cells underlie its pathogenesis. METHODS In this study, we used Sanger sequencing and next-generation sequencing (NGS)-based gene panel screening to investigate a family of three patients with CSNB inherited in an apparent autosomal dominant pattern. We expected to find out the disease-causing gene defects carried by this family. RESULTS We found that the patients in this family did not carry the RHO, GNAT1, or PDE6B mutation, but carried compound heterozygotes mutations of GRM6. Three deleterious GRM6 variants, p.Arg621Ter, p.Gly51Val, and p.Gly464Arg, were found to be co-segregating with the disease, causing a pseudodominant inheritance of GRM6-related autosomal recessive complete CSNB. CONCLUSION This study presents a rare case of autosomal recessive CSNB (arCSNB) pseudodominant inheritance, which potentially leads us to expand our gene candidate list in future genetic testing for apparent dominant pedigrees. The discovery of the two novel likely pathogenic variants p.Gly51Val and p.Gly464Arg could broaden our knowledge about the genetics of CSNB and provide insights into the structure and function of the GRM6 protein.
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Affiliation(s)
- Hong-Yan Liu
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Jia Huang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Hai Xiao
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Ming-Jie Zhang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Fei-Fei Shi
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Ying-Hai Jiang
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
| | - Han Du
- Institute of Medical Genetics, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, School of Clinical Medicine, Henan University, Zhengzhou, China
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16
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Das RG, Becker D, Jagannathan V, Goldstein O, Santana E, Carlin K, Sudharsan R, Leeb T, Nishizawa Y, Kondo M, Aguirre GD, Miyadera K. Genome-wide association study and whole-genome sequencing identify a deletion in LRIT3 associated with canine congenital stationary night blindness. Sci Rep 2019; 9:14166. [PMID: 31578364 PMCID: PMC6775105 DOI: 10.1038/s41598-019-50573-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 09/05/2019] [Indexed: 01/11/2023] Open
Abstract
Congenital stationary night blindness (CSNB), in the complete form, is caused by dysfunctions in ON-bipolar cells (ON-BCs) which are secondary neurons of the retina. We describe the first disease causative variant associated with CSNB in the dog. A genome-wide association study using 12 cases and 11 controls from a research colony determined a 4.6 Mb locus on canine chromosome 32. Subsequent whole-genome sequencing identified a 1 bp deletion in LRIT3 segregating with CSNB. The canine mutant LRIT3 gives rise to a truncated protein with unaltered subcellular expression in vitro. Genetic variants in LRIT3 have been associated with CSNB in patients although there is limited evidence regarding its apparently critical function in the mGluR6 pathway in ON-BCs. We determine that in the canine CSNB retina, the mutant LRIT3 is correctly localized to the region correlating with the ON-BC dendritic tips, albeit with reduced immunolabelling. The LRIT3-CSNB canine model has direct translational potential enabling studies to help understand the CSNB pathogenesis as well as to develop new therapies targeting the secondary neurons of the retina.
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Affiliation(s)
- Rueben G Das
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Pennsylvania, United States of America
| | - Doreen Becker
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Pennsylvania, United States of America.,Institute of Genome Biology, Leibniz Institute for Farm Animal Biology, Dummerstorf, Germany
| | | | - Orly Goldstein
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, Ithaca, New York, United States of America
| | - Evelyn Santana
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Pennsylvania, United States of America
| | - Kendall Carlin
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Pennsylvania, United States of America
| | - Raghavi Sudharsan
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Pennsylvania, United States of America
| | - Tosso Leeb
- Institute of Genetics, University of Bern, Bern, Switzerland
| | - Yuji Nishizawa
- Department of Biomedical Sciences, Chubu University, Kasugai, Aichi, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Gustavo D Aguirre
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Pennsylvania, United States of America
| | - Keiko Miyadera
- Department of Clinical Sciences and Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Pennsylvania, United States of America.
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17
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TRPM1 Mutations are the Most Common Cause of Autosomal Recessive Congenital Stationary Night Blindness (CSNB) in the Palestinian and Israeli Populations. Sci Rep 2019; 9:12047. [PMID: 31427709 PMCID: PMC6700182 DOI: 10.1038/s41598-019-46811-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 06/14/2019] [Indexed: 11/08/2022] Open
Abstract
Precise genetic and phenotypic characterization of congenital stationary night blindness (CSNB) patients is needed for future therapeutic interventions. The aim of this study was to estimate the prevalence of CSNB in our populations and to study clinical and genetic aspects of the autosomal recessive (AR) form of CSNB. This is a retrospective cohort study of Palestinian and Israeli CSNB patients harboring mutations in TRPM1 underwent comprehensive ocular examination. Genetic analysis was performed using homozygosity mapping and sequencing. 161 patients (from 76 families) were recruited for this study, leading to a prevalence of 1:6210 in the vicinity of Jerusalem, much higher than the worldwide prevalence. 61% of the families were consanguineous with AR inheritance pattern. Biallelic pathogenic TRPM1 mutations were identified in 36 families (72 patients). Two founder mutations explain the vast majority of cases: a nonsense mutation c.880A>T (p.Lys294*) identified in 22 Palestinian families and a large genomic deletion (36,445 bp) encompassing exons 2-7 of TRPM1 present in 13 Ashkenazi Jewish families. Most patients were myopic (with mean BCVA of 0.40 LogMAR) and all had absent rod responses in full field electroretinography. To the best of our knowledge, this is the largest report of a clinical and genetic analysis of patients affected with CSNB due to TRPM1 mutations.
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18
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Zhou C, Zhang W, Wen Q, Bu P, Gao J, Wang G, Jin J, Song Y, Sun X, Zhang Y, Jiang X, Yu H, Peng C, Shen Y, Price M, Li J, Zhang X, Fan Z, Yue B. Comparative Genomics Reveals the Genetic Mechanisms of Musk Secretion and Adaptive Immunity in Chinese Forest Musk Deer. Genome Biol Evol 2019; 11:1019-1032. [PMID: 30903183 PMCID: PMC6450037 DOI: 10.1093/gbe/evz055] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2019] [Indexed: 02/05/2023] Open
Abstract
The Chinese forest musk deer (Moschus berezovskii; FMD) is an artiodactyl mammal and is both economically valuable and highly endangered. To investigate the genetic mechanisms of musk secretion and adaptive immunity in FMD, we compared its genome to nine other artiodactyl genomes. Comparative genomics demonstrated that eight positively selected genes (PSGs) in FMD were annotated in three KEGG pathways that were related to metabolic and synthetic activity of musk, similar to previous transcriptome studies. Functional enrichment analysis indicated that many PSGs were involved in the regulation of immune system processes, implying important reorganization of the immune system in FMD. FMD-specific missense mutations were found in two PSGs (MHC class II antigen DRA and ADA) that were classified as deleterious by PolyPhen-2, possibly contributing to immune adaptation to infectious diseases. Functional assessment showed that the FMD-specific mutation enhanced the ADA activity, which was likely to strengthen the immune defense against pathogenic invasion. Single nucleotide polymorphism-based inference showed the recent demographic trajectory for FMD. Our data and findings provide valuable genomic resources not only for studying the genetic mechanisms of musk secretion and adaptive immunity, but also for facilitating more effective management of the captive breeding programs for this endangered species.
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Affiliation(s)
- Chuang Zhou
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Wenbo Zhang
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Qinchao Wen
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Ping Bu
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Jie Gao
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Guannan Wang
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Jiazheng Jin
- Sichuan Engineering Research Center for Medicinal Animals, Xichang, P.R. China
| | - Yinjie Song
- Center of Infectious Diseases, West China Hospital, Sichuan University and Collaborative Innovation Center of Biotherapy, Chengdu, P.R. China
| | - Xiaohong Sun
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Yifan Zhang
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Xue Jiang
- Sichuan Engineering Research Center for Medicinal Animals, Xichang, P.R. China
| | - Haoran Yu
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Changjun Peng
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Yongmei Shen
- Sichuan Engineering Research Center for Medicinal Animals, Xichang, P.R. China
| | - Megan Price
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Jing Li
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Xiuyue Zhang
- Sichuan Key Laboratory of Conservation Biology on Endangered Wildlife, College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Zhenxin Fan
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
| | - Bisong Yue
- Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, P.R. China
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19
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Vilariño-Güell C, Zimprich A, Martinelli-Boneschi F, Herculano B, Wang Z, Matesanz F, Urcelay E, Vandenbroeck K, Leyva L, Gris D, Massaad C, Quandt JA, Traboulsee AL, Encarnacion M, Bernales CQ, Follett J, Yee IM, Criscuoli MG, Deutschländer A, Reinthaler EM, Zrzavy T, Mascia E, Zauli A, Esposito F, Alcina A, Izquierdo G, Espino-Paisán L, Mena J, Antigüedad A, Urbaneja-Romero P, Ortega-Pinazo J, Song W, Sadovnick AD. Exome sequencing in multiple sclerosis families identifies 12 candidate genes and nominates biological pathways for the genesis of disease. PLoS Genet 2019; 15:e1008180. [PMID: 31170158 PMCID: PMC6553700 DOI: 10.1371/journal.pgen.1008180] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 05/07/2019] [Indexed: 12/12/2022] Open
Abstract
Multiple sclerosis (MS) is an inflammatory disease of the central nervous system characterized by myelin loss and neuronal dysfunction. Although the majority of patients do not present familial aggregation, Mendelian forms have been described. We performed whole-exome sequencing analysis in 132 patients from 34 multi-incident families, which nominated likely pathogenic variants for MS in 12 genes of the innate immune system that regulate the transcription and activation of inflammatory mediators. Rare missense or nonsense variants were identified in genes of the fibrinolysis and complement pathways (PLAU, MASP1, C2), inflammasome assembly (NLRP12), Wnt signaling (UBR2, CTNNA3, NFATC2, RNF213), nuclear receptor complexes (NCOA3), and cation channels and exchangers (KCNG4, SLC24A6, SLC8B1). These genes suggest a disruption of interconnected immunological and pro-inflammatory pathways as the initial event in the pathophysiology of familial MS, and provide the molecular and biological rationale for the chronic inflammation, demyelination and neurodegeneration observed in MS patients.
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Affiliation(s)
| | | | - Filippo Martinelli-Boneschi
- Laboratory of Human Genetics of Neurological Disorders, CNS Inflammatory Unit, Institute of Experimental Neurology, IRCCS San Raffaele Scientific Institute, Milan, Italy
- MS Unit and Department of Neurology, IRCCS Policlinico San Donato, Milan, Italy
- Department of Biomedical Sciences for Health, University of Milan, Milan, Italy
| | - Bruno Herculano
- Townsend Family Laboratories, Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - Zhe Wang
- Townsend Family Laboratories, Department of Psychiatry, University of British Columbia, Vancouver, Canada
- National Clinical Research Center for Geriatric Diseases, Xuanwu Hospital of the Capital Medical University, Beijing, China
| | - Fuencisla Matesanz
- Department of Cell Biology and Immunology, Instituto de Parasitología y Biomedicina López Neyra (IPBLN), CSIC, Granada, Spain
| | - Elena Urcelay
- Immunology Dept, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
- Red Española de Esclerosis Múltiple REEM, Madrid, Spain
| | - Koen Vandenbroeck
- Achucarro Basque Center for Neuroscience, Universidad del País Vasco (UPV/EHU), Leioa, Spain
- Ikerbasque, Basque Foundation for Science, Bilbao, Spain
| | - Laura Leyva
- Red Española de Esclerosis Múltiple REEM, Madrid, Spain
- Instituto de Investigación Biomédica de Málaga-IBIMA, Unidad de Gestion Clínica de Neurociencias, Hospital Regional Universitario de Málaga, Málaga, Spain
| | - Denis Gris
- Division of Immunology, Department of Pediatrics, CR-CHUS, Faculty of Medicine and Health Sciences, University of Sherbrooke, Sherbrooke, Canada
| | - Charbel Massaad
- Toxicology, Pharmacology and Cell Signalisation—UMR-S 1124 Université Paris Descartes, Paris, France
| | - Jacqueline A. Quandt
- Department of Pathology, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Anthony L. Traboulsee
- Division of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Mary Encarnacion
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Cecily Q. Bernales
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Jordan Follett
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Irene M. Yee
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Maria G. Criscuoli
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
| | - Angela Deutschländer
- Department of Neurology, Mayo Clinic Florida, Jacksonville, FL, United States of America
- Department of Clinical Genomics, Mayo Clinic Florida, Jacksonville, FL, United States of America
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL, United States of America
| | - Eva M. Reinthaler
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Tobias Zrzavy
- Department of Neurology, Medical University of Vienna, Vienna, Austria
| | - Elisabetta Mascia
- Laboratory of Human Genetics of Neurological Disorders, CNS Inflammatory Unit, Institute of Experimental Neurology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Andrea Zauli
- Laboratory of Human Genetics of Neurological Disorders, CNS Inflammatory Unit, Institute of Experimental Neurology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Federica Esposito
- Laboratory of Human Genetics of Neurological Disorders, CNS Inflammatory Unit, Institute of Experimental Neurology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Antonio Alcina
- Department of Cell Biology and Immunology, Instituto de Parasitología y Biomedicina López Neyra (IPBLN), CSIC, Granada, Spain
| | | | - Laura Espino-Paisán
- Immunology Dept, Hospital Clínico San Carlos, Instituto de Investigación Sanitaria del Hospital Clínico San Carlos (IdISSC), Madrid, Spain
- Red Española de Esclerosis Múltiple REEM, Madrid, Spain
| | - Jorge Mena
- Achucarro Basque Center for Neuroscience, Universidad del País Vasco (UPV/EHU), Leioa, Spain
| | - Alfredo Antigüedad
- Neurology Department, Hospital Universitario de Cruces, S/N, Baracaldo, Spain
| | - Patricia Urbaneja-Romero
- Red Española de Esclerosis Múltiple REEM, Madrid, Spain
- Instituto de Investigación Biomédica de Málaga-IBIMA, Unidad de Gestion Clínica de Neurociencias, Hospital Regional Universitario de Málaga, Málaga, Spain
| | - Jesús Ortega-Pinazo
- Instituto de Investigación Biomédica de Málaga-IBIMA, Unidad de Gestion Clínica de Neurociencias, Hospital Regional Universitario de Málaga, Málaga, Spain
| | - Weihong Song
- Townsend Family Laboratories, Department of Psychiatry, University of British Columbia, Vancouver, Canada
| | - A. Dessa Sadovnick
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
- Division of Neurology, Faculty of Medicine, University of British Columbia, Vancouver, Canada
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20
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Vinberg F, Chen J, Kefalov VJ. Regulation of calcium homeostasis in the outer segments of rod and cone photoreceptors. Prog Retin Eye Res 2018; 67:87-101. [PMID: 29883715 DOI: 10.1016/j.preteyeres.2018.06.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/30/2018] [Accepted: 06/04/2018] [Indexed: 12/11/2022]
Abstract
Calcium plays important roles in the function and survival of rod and cone photoreceptor cells. Rapid regulation of calcium in the outer segments of photoreceptors is required for the modulation of phototransduction that drives the termination of the flash response as well as light adaptation in rods and cones. On a slower time scale, maintaining proper calcium homeostasis is critical for the health and survival of photoreceptors. Decades of work have established that the level of calcium in the outer segments of rods and cones is regulated by a dynamic equilibrium between influx via the transduction cGMP-gated channels and extrusion via rod- and cone-specific Na+/Ca2+, K+ exchangers (NCKXs). It had been widely accepted that the only mechanism for extrusion of calcium from rod outer segments is via the rod-specific NCKX1, while extrusion from cone outer segments is driven exclusively by the cone-specific NCKX2. However, recent evidence from mice lacking NCKX1 and NCKX2 have challenged that notion and have revealed a more complex picture, including a NCKX-independent mechanism in rods and two separate NCKX-dependent mechanisms in cones. This review will focus on recent findings on the molecular mechanisms of extrusion of calcium from the outer segments of rod and cone photoreceptors, and the functional and structural changes in photoreceptors when normal extrusion is disrupted.
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Affiliation(s)
- Frans Vinberg
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, USA; John A. Moran Eye Center, University of Utah, Salt Lake City, UT, USA
| | - Jeannie Chen
- Zilkha Neurogenetic Institute, Department of Physiology and Neuroscience, University of Southern California Keck School of Medicine, Los Angeles, CA, USA
| | - Vladimir J Kefalov
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, Missouri, USA.
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21
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Stunkel ML, Brodie SE, Cideciyan AV, Pfeifer WL, Kennedy EL, Stone EM, Jacobson SG, Drack AV. Expanded Retinal Disease Spectrum Associated With Autosomal Recessive Mutations in GUCY2D. Am J Ophthalmol 2018; 190:58-68. [PMID: 29559409 DOI: 10.1016/j.ajo.2018.03.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 03/06/2018] [Accepted: 03/11/2018] [Indexed: 11/17/2022]
Abstract
PURPOSE GUCY2D has been associated with autosomal recessive Leber congenital amaurosis and autosomal dominant cone-rod dystrophy. This report expands the phenotype of autosomal recessive mutations to congenital night blindness, which may slowly progress to mild retinitis pigmentosa. DESIGN Retrospective case series. METHODS Multicenter study of 5 patients (3 male, 2 female). RESULTS All patients presented with night blindness since childhood. Age at referral was 9-45 years. Length of follow-up was 1-7 years. Best-corrected visual acuity at presentation ranged from 20/15 to 20/30 and at most recent visit averaged 20/25. No patient had nystagmus or high refractive error. ISCEV standard electroretinography revealed nondetectable dark-adapted dim flash responses and reduced amplitude but not electronegative dark-adapted bright flash responses with similar waveforms to the reduced-amplitude light-adapted single flash responses. The 30 Hz flicker responses were relatively preserved. Macular optical coherence tomography revealed normal lamination in 3 patients, with abnormalities in 2. Goldmann visual fields were normal at presentation in children but constricted in 1 adult. One child showed loss of midperipheral fields over time. Fundus appearance was normal in childhood; the adult had sparse bone spicule-like pigmentation. Full-field stimulus testing (FST) revealed markedly decreased retinal sensitivity to light. Dark adaptation demonstrated lack of rod-cone break. Two patients had tritanopia. All 5 had compound heterozygous mutations in GUCY2D. Three of the 5 patients harbor the Arg768Trp mutation reported in GUCY2D-associated Leber congenital amaurosis. CONCLUSIONS Autosomal recessive GUCY2D mutations may cause congenital night blindness with normal acuity and refraction, and unique electroretinography. Progression to mild retinitis pigmentosa may occur.
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Affiliation(s)
- Maria L Stunkel
- Institute for Vision Research, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Scott E Brodie
- Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Wanda L Pfeifer
- Institute for Vision Research, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Elizabeth L Kennedy
- Institute for Vision Research, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Edwin M Stone
- Institute for Vision Research, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Arlene V Drack
- Institute for Vision Research, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa, USA.
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22
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A Novel Heterozygous Missense Mutation in GNAT1 Leads to Autosomal Dominant Riggs Type of Congenital Stationary Night Blindness. BIOMED RESEARCH INTERNATIONAL 2018; 2018:7694801. [PMID: 29850563 PMCID: PMC5937575 DOI: 10.1155/2018/7694801] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 03/13/2018] [Indexed: 01/03/2023]
Abstract
Autosomal dominant congenital stationary night blindness (adCSNB) is rare and results from altered phototransduction giving a Riggs type of electroretinogram (ERG) with loss of the rod a-wave and small b-waves. These patients usually have normal vision in light. Only few mutations in genes coding for proteins of the phototransduction cascade lead to this condition; most of these gene defects cause progressive rod-cone dystrophy. Mutation analysis of an adCSNB family with a Riggs-type ERG revealed a novel variant (c.155T>A p.Ile52Asn) in GNAT1 coding for the α-subunit of transducin, cosegregating with the phenotype. Domain predictions and 3D-modelling suggest that the variant does not affect the GTP-binding site as other GNAT1 adCSNB mutations do. It affects a predicted nuclear localization signal and a part of the first α-helix, which is distant from the GTP-binding site. The subcellular protein localization of this and other mutant GNAT1 proteins implicated in CSNB are unaltered in mammalian GNAT1 overexpressing cells. Our findings add a third GNAT1 mutation causing adCSNB and suggest that different pathogenic mechanisms may cause this condition.
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23
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Li J, Zhang Q. Insight into the molecular genetics of myopia. Mol Vis 2017; 23:1048-1080. [PMID: 29386878 PMCID: PMC5757860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2017] [Accepted: 12/29/2017] [Indexed: 11/18/2022] Open
Abstract
Myopia is the most common cause of visual impairment worldwide. Genetic and environmental factors contribute to the development of myopia. Studies on the molecular genetics of myopia are well established and have implicated the important role of genetic factors. With linkage analysis, association studies, sequencing analysis, and experimental myopia studies, many of the loci and genes associated with myopia have been identified. Thus far, there has been no systemic review of the loci and genes related to non-syndromic and syndromic myopia based on the different approaches. Such a systemic review of the molecular genetics of myopia will provide clues to identify additional plausible genes for myopia and help us to understand the molecular mechanisms underlying myopia. This paper reviews recent genetic studies on myopia, summarizes all possible reported genes and loci related to myopia, and suggests implications for future studies on the molecular genetics of myopia.
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Affiliation(s)
- Jiali Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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24
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Abeshi A, Coppola P, Beccari T, Dundar M, Viola F, Colombo L, Bertelli M. Genetic testing for congenital stationary night blindness. EUROBIOTECH JOURNAL 2017. [DOI: 10.24190/issn2564-615x/2017/s1.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Abstract
We studied the scientific literature and disease guidelines in order to summarize the clinical utility of the genetic test for congenital stationary night blindness (CSNB). CSNB is inherited in an autosomal dominant manner in the case of mutations in the GNAT1, PDE6B and RHO genes, in an autosomal recessive manner in the case of mutations in the CABP4, GNB3, GPR179, GRM6, LRIT3, SAG, SLC24A1, TRPM1 and genes and in an X-linked recessive manner in the case of mutations in the CACNA1F and NYX genes. The overall prevalence of CSNB is not known. Clinical diagnosis is based on clinical findings, ophthalmological examination, visual evoked potentials and electroretinography. The genetic test is useful for confirming diagnosis and for differential diagnosis, couple risk assessment and access to clinical trials.
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Affiliation(s)
- Andi Abeshi
- MAGI Balkans, Tirana , Albania
- MAGI’S Lab, Rovereto , Italy
| | | | - Tommaso Beccari
- Department of Pharmaceutical Sciences, University of Perugia, Perugia , Italy
| | - Munis Dundar
- Department of Medical Genetics, Erciyes University Medical School, Kayseri , Turkey
| | - Francesco Viola
- Department of Clinical Sciences and Community Health, University of Milan, Ophthalmological Unit, IRCCS-Cà Granda Foundation-Ospedale Maggiore Policlinico, Milan , Italy
| | - Leonardo Colombo
- Department of Ophthalmology, ASST Santi Paolo e Carlo, University of Milan, Milan , Italy
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25
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Vinberg F, Wang T, De Maria A, Zhao H, Bassnett S, Chen J, Kefalov VJ. The Na +/Ca 2+, K + exchanger NCKX4 is required for efficient cone-mediated vision. eLife 2017. [PMID: 28650316 PMCID: PMC5515578 DOI: 10.7554/elife.24550] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Calcium (Ca2+) plays an important role in the function and health of neurons. In vertebrate cone photoreceptors, Ca2+ controls photoresponse sensitivity, kinetics, and light adaptation. Despite the critical role of Ca2+ in supporting the function and survival of cones, the mechanism for its extrusion from cone outer segments is not well understood. Here, we show that the Na+/Ca2+, K+ exchanger NCKX4 is expressed in zebrafish, mouse, and primate cones. Functional analysis of NCKX4-deficient mouse cones revealed that this exchanger is essential for the wide operating range and high temporal resolution of cone-mediated vision. We show that NCKX4 shapes the cone photoresponse together with the cone-specific NCKX2: NCKX4 acts early to limit response amplitude, while NCKX2 acts late to further accelerate response recovery. The regulation of Ca2+ by NCKX4 in cones is a novel mechanism that supports their ability to function as daytime photoreceptors and promotes their survival. DOI:http://dx.doi.org/10.7554/eLife.24550.001 Cells known as photoreceptors sense light in the eye. Light activates signaling pathways inside the photoreceptors that relay visual information to nerve cells, which carry the information to the brain. Photoreceptors called cone cells allow us to distinguish different colors of light and therefore play an important role in daytime vision. Over the course of the day, the overall levels of light in the environment can vary widely and so photoreceptors need to be able to adjust their signaling pathways so that they can still respond to light stimuli. Calcium ions modulate the signaling pathways inside cone cells to help them adjust to changing light levels. These ions also play other important roles in the health and activity of photoreceptors, so the cells need to carefully control how many calcium ions they contain. Cone cells contain a structure known as the outer segment, which is responsible for detecting light stimuli. It is believed that cones control the levels of calcium ions in the outer segment by balancing the flow of calcium ions into and out of the segment. The calcium ions enter the outer segment via channels that sit in the membrane surrounding the cell. A transporter protein known as NCKX2, which is only found in cone cells, was thought to pump the calcium ions out of the cell. However, recent data has challenged this idea by demonstrating that NCKX2 only plays a minor role in this process. Vinberg et al. investigated how calcium ions leave the outer segments of cone cells in several different animals. The experiments show that a transporter protein called NCKX4 – which belongs to the same protein family as NCKX2 – is the main transporter involved in removing calcium ions from the cone cells of mice. Loss of NCKX4 from mouse cones reduced the ability of these cells to respond to fast and rapidly changing light stimuli, and to operate in bright light. Further experiments show that NCKX4 is also found in the outer segments of zebrafish and monkey cone cells. The next challenges will be to find out if NCKX4 is also present in human cones and whether it plays a role in regulating our daytime vision. DOI:http://dx.doi.org/10.7554/eLife.24550.002
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Affiliation(s)
- Frans Vinberg
- Department of Ophthalmology and Visual Sciences, Washington University, St. Louis, United States
| | - Tian Wang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, United States.,Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, United States.,Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Alicia De Maria
- Department of Ophthalmology and Visual Sciences, Washington University, St. Louis, United States
| | - Haiqing Zhao
- Department of Biology, Johns Hopkins University, Baltimore, United States
| | - Steven Bassnett
- Department of Ophthalmology and Visual Sciences, Washington University, St. Louis, United States
| | - Jeannie Chen
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, United States.,Department of Cell and Neurobiology, Keck School of Medicine, University of Southern California, Los Angeles, United States.,Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, United States
| | - Vladimir J Kefalov
- Department of Ophthalmology and Visual Sciences, Washington University, St. Louis, United States
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Robertson SYT, Wen X, Yin K, Chen J, Smith CE, Paine ML. Multiple Calcium Export Exchangers and Pumps Are a Prominent Feature of Enamel Organ Cells. Front Physiol 2017; 8:336. [PMID: 28588505 PMCID: PMC5440769 DOI: 10.3389/fphys.2017.00336] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 05/08/2017] [Indexed: 12/11/2022] Open
Abstract
Calcium export is a key function for the enamel organ during all stages of amelogenesis. Expression of a number of ATPase calcium transporting, plasma membrane genes (ATP2B1-4/PMCA1-4), solute carrier SLC8A genes (sodium/calcium exchanger or NCX1-3), and SLC24A gene family members (sodium/potassium/calcium exchanger or NCKX1-6) have been investigated in the developing enamel organ in earlier studies. This paper reviews the calcium export pathways that have been described and adds novel insights to the spatiotemporal expression patterns of PMCA1, PMCA4, and NCKX3 during amelogenesis. New data are presented to show the mRNA expression profiles for the four Atp2b1-4 gene family members (PMCA1-4) in secretory-stage and maturation-stage rat enamel organs. These data are compared to expression profiles for all Slc8a and Slc24a gene family members. PMCA1, PMCA4, and NCKX3 immunolocalization data is also presented. Gene expression profiles quantitated by real time PCR show that: (1) PMCA1, 3, and 4, and NCKX3 are most highly expressed during secretory-stage amelogenesis; (2) NCX1 and 3, and NCKX6 are expressed during secretory and maturation stages; (3) NCKX4 is most highly expressed during maturation-stage amelogenesis; and (4) expression levels of PMCA2, NCX2, NCKX1, NCKX2, and NCKX5 are negligible throughout amelogenesis. In the enamel organ PMCA1 localizes to the basolateral membrane of both secretory and maturation ameloblasts; PMCA4 expression is seen in the basolateral membrane of secretory and maturation ameloblasts, and also cells of the stratum intermedium and papillary layer; while NCKX3 expression is limited to Tomes' processes, and the apical membrane of maturation-stage ameloblasts. These new findings are discussed in the perspective of data already present in the literature, and highlight the multiplicity of calcium export systems in the enamel organ needed to regulate biomineralization.
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Affiliation(s)
- Sarah Y T Robertson
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
| | - Xin Wen
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
| | - Kaifeng Yin
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
| | - Junjun Chen
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States.,Department of Oral Medicine, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of MedicineShanghai, China.,Shanghai Key Laboratory of Tumor Microenvironment and Inflammation, Department of Biochemistry and Molecular Cell Biology, Shanghai Jiao Tong University School of MedicineShanghai, China
| | - Charles E Smith
- Department of Anatomy and Cell Biology, Faculty of Medicine, McGill UniversityMontreal, QC, Canada
| | - Michael L Paine
- Center for Craniofacial Molecular Biology, Herman Ostrow School of Dentistry, University of Southern CaliforniaLos Angeles, CA, United States
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27
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Li L, Chen Y, Jiao X, Jin C, Jiang D, Tanwar M, Ma Z, Huang L, Ma X, Sun W, Chen J, Ma Y, M'hamdi O, Govindarajan G, Cabrera PE, Li J, Gupta N, Naeem MA, Khan SN, Riazuddin S, Akram J, Ayyagari R, Sieving PA, Riazuddin SA, Hejtmancik JF. Homozygosity Mapping and Genetic Analysis of Autosomal Recessive Retinal Dystrophies in 144 Consanguineous Pakistani Families. Invest Ophthalmol Vis Sci 2017; 58:2218-2238. [PMID: 28418496 PMCID: PMC5397137 DOI: 10.1167/iovs.17-21424] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Purpose The Pakistan Punjab population has been a rich source for identifying genes causing or contributing to autosomal recessive retinal degenerations (arRD). This study was carried out to delineate the genetic architecture of arRD in the Pakistani population. Methods The genetic origin of arRD in a total of 144 families selected only for having consanguineous marriages and multiple members affected with arRD was examined. Of these, causative mutations had been identified in 62 families while only the locus had been identified for an additional 15. The remaining 67 families were subjected to homozygosity exclusion mapping by screening of closely flanking microsatellite markers at 180 known candidate genes/loci followed by sequencing of the candidate gene for pathogenic changes. Results Of these 67 families subjected to homozygosity mapping, 38 showed homozygosity for at least one of the 180 regions, and sequencing of the corresponding genes showed homozygous cosegregating mutations in 27 families. Overall, mutations were detected in approximately 61.8 % (89/144) of arRD families tested, with another 10.4% (15/144) being mapped to a locus but without a gene identified. Conclusions These results suggest the involvement of unmapped novel genes in the remaining 27.8% (40/144) of families. In addition, this study demonstrates that homozygosity mapping remains a powerful tool for identifying the genetic defect underlying genetically heterogeneous arRD disorders in consanguineous marriages for both research and clinical applications.
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Affiliation(s)
- Lin Li
- Department of Ophthalmology, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China 2Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Yabin Chen
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Xiaodong Jiao
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Chongfei Jin
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 3Department of Medicine, Brookdale University Hospital and Medical Center, New York, New York, United States
| | - Dan Jiang
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Mukesh Tanwar
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 4Department of Genetics, Maharshi Dayanand University Rohtak, Haryana, India
| | - Zhiwei Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Li Huang
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 5State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Xiaoyin Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 6Laboratory of Developmental Cell Biology and Disease, School of Ophthalmology and Optometry and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Wenmin Sun
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 5State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Jianjun Chen
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 7Department of Ophthalmology, Shanghai Tenth People's Hospital, and Tongji Eye Institute, Tongji University School of Medicine, Shanghai, China
| | - Yan Ma
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Oussama M'hamdi
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Gowthaman Govindarajan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Patricia E Cabrera
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Jiali Li
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States 5State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, China
| | - Nikhil Gupta
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Shaheen N Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan 9Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan 10National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan 10National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Radha Ayyagari
- Shiley Eye Institute, University of California-San Diego, La Jolla, California, United States
| | - Paul A Sieving
- National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - S Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States 14McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - J Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
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28
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The mutation p.E113K in the Schiff base counterion of rhodopsin is associated with two distinct retinal phenotypes within the same family. Sci Rep 2016; 6:36208. [PMID: 27812022 PMCID: PMC5095885 DOI: 10.1038/srep36208] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 10/12/2016] [Indexed: 02/05/2023] Open
Abstract
The diagnoses of retinitis pigmentosa (RP) and stationary night blindness (CSNB) are two distinct clinical entities belonging to a group of clinically and genetically heterogeneous retinal diseases. The current study focused on the identification of causative mutations in the RP-affected index patient and in several members of the same family that reported a phenotype resembling CSNB. Ophthalmological examinations of the index patient confirmed a typical form of RP. In contrast, clinical characterizations and ERGs of another affected family member showed the Riggs-type CSNB lacking signs of RP. Applying whole exome sequencing we detected the non-synonymous substitution c.337G > A, p.E113 K in the rhodopsin (RHO) gene. The mutation co-segregated with the diseases. The identification of the pathogenic variant p.E113 K is the first description of a naturally-occurring mutation in the Schiff base counterion of RHO in human patients. The heterozygous mutation c.337G > A in exon 1 was confirmed in the index patient as well as in five CSNB-affected relatives. This pathogenic sequence change was excluded in a healthy family member and in 199 ethnically matched controls. Our findings suggest that a mutation in the biochemically well-characterized counterion p.E113 in RHO can be associated with RP or Riggs-type CSNB, even within the same family.
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29
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Vincent A, Audo I, Tavares E, Maynes J, Tumber A, Wright T, Li S, Michiels C, Condroyer C, MacDonald H, Verdet R, Sahel JA, Hamel CP, Zeitz C, Héon E, Banin E, Bocquet B, De Baere E, Casteels I, Defoort-Dhellemmes S, Drumare I, Friedburg C, Gottlob I, Jacobson S, Kellner U, Koenekoop R, Kohl S, Leroy B, Lorenz B, McLean R, Meire F, Meunier I, Munier F, de Ravel T, Reiff C, Mohand-Saïd S, Sharon D, Schorderet D, Schwartz S, Zanlonghi X. Biallelic Mutations in GNB3 Cause a Unique Form of Autosomal-Recessive Congenital Stationary Night Blindness. Am J Hum Genet 2016; 98:1011-1019. [PMID: 27063057 DOI: 10.1016/j.ajhg.2016.03.021] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 03/18/2016] [Indexed: 01/13/2023] Open
Abstract
Congenital stationary night blindness (CSNB) is a heterogeneous group of non-progressive inherited retinal disorders with characteristic electroretinogram (ERG) abnormalities. Riggs and Schubert-Bornschein are subtypes of CSNB and demonstrate distinct ERG features. Riggs CSNB demonstrates selective rod photoreceptor dysfunction and occurs due to mutations in genes encoding proteins involved in rod phototransduction cascade; night blindness is the only symptom and eye examination is otherwise normal. Schubert-Bornschein CSNB is a consequence of impaired signal transmission between the photoreceptors and bipolar cells. Schubert-Bornschein CSNB is subdivided into complete CSNB with an ON bipolar signaling defect and incomplete CSNB with both ON and OFF pathway involvement. Both subtypes are associated with variable degrees of night blindness or photophobia, reduced visual acuity, high myopia, and nystagmus. Whole-exome sequencing of a family screened negative for mutations in genes associated with CSNB identified biallelic mutations in the guanine nucleotide-binding protein subunit beta-3 gene (GNB3). Two siblings were compound heterozygous for a deletion (c.170_172delAGA [p.Lys57del]) and a nonsense mutation (c.1017G>A [p.Trp339(∗)]). The maternal aunt was homozygous for the nonsense mutation (c.1017G>A [p.Trp339(∗)]). Mutational analysis of GNB3 in a cohort of 58 subjects with CSNB identified a sporadic case individual with a homozygous GNB3 mutation (c.200C>T [p.Ser67Phe]). GNB3 encodes the β subunit of G protein heterotrimer (Gαβγ) and is known to modulate ON bipolar cell signaling and cone transducin function in mice. Affected human subjects showed an unusual CSNB phenotype with variable degrees of ON bipolar dysfunction and reduced cone sensitivity. This unique retinal disorder with dual anomaly in visual processing expands our knowledge about retinal signaling.
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Biswas P, Chavali VRM, Agnello G, Stone E, Chakarova C, Duncan JL, Kannabiran C, Homsher M, Bhattacharya SS, Naeem MA, Kimchi A, Sharon D, Iwata T, Riazuddin S, Reddy GB, Hejtmancik JF, Georgiou G, Riazuddin SA, Ayyagari R. A missense mutation in ASRGL1 is involved in causing autosomal recessive retinal degeneration. Hum Mol Genet 2016; 25:2483-2497. [PMID: 27106100 DOI: 10.1093/hmg/ddw113] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 03/22/2016] [Accepted: 04/11/2016] [Indexed: 12/31/2022] Open
Abstract
Inherited retinal dystrophies are a group of genetically heterogeneous conditions with broad phenotypic heterogeneity. We analyzed a large five-generation pedigree with early-onset recessive retinal degeneration to identify the causative mutation. Linkage analysis and homozygosity mapping combined with exome sequencing were carried out to map the disease locus and identify the p.G178R mutation in the asparaginase like-1 gene (ASRGL1), segregating with the retinal dystrophy phenotype in the study pedigree. ASRGL1 encodes an enzyme that catalyzes the hydrolysis of L-asparagine and isoaspartyl-peptides. Studies on the ASRGL1 expressed in Escherichia coli and transiently transfected mammalian cells indicated that the p.G178R mutation impairs the autocatalytic processing of this enzyme resulting in the loss of functional ASRGL1 and leaving the inactive precursor protein as a destabilized and aggregation-prone protein. A zebrafish model overexpressing the mutant hASRGL1 developed retinal abnormalities and loss of cone photoreceptors. Our studies suggest that the p.G178R mutation in ASRGL1 leads to photoreceptor degeneration resulting in progressive vision loss.
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Affiliation(s)
- Pooja Biswas
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
| | - Venkata Ramana Murthy Chavali
- Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA.,Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | - Giulia Agnello
- Departments of Biomedical and Chemical Engineering, Molecular Biosciences, Section of Molecular Genetics and Microbiology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - Everett Stone
- Departments of Biomedical and Chemical Engineering, Molecular Biosciences, Section of Molecular Genetics and Microbiology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | | | - Jacque L Duncan
- Ophthalmology, University of California San Francisco, San Francisco, CA, USA
| | - Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, L V Prasad Eye Institute (LVPEI), Kallam Anji Reddy Campus, L V Prasad Marg, Hyderabad 500 034, India
| | - Melissa Homsher
- Ophthalmology, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Adva Kimchi
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Takeshi Iwata
- Division of Molecular and Cellular Biology, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Shaikh Riazuddin
- Allama Iqbal Medical College, University of Health Sciences Lahore, Pakistan.,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | | | | | - George Georgiou
- Departments of Biomedical and Chemical Engineering, Molecular Biosciences, Section of Molecular Genetics and Microbiology, and Institute for Cell and Molecular Biology, The University of Texas at Austin, Austin, TX, USA
| | - S Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla, CA, USA
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Neuillé M, Malaichamy S, Vadalà M, Michiels C, Condroyer C, Sachidanandam R, Srilekha S, Arokiasamy T, Letexier M, Démontant V, Sahel JA, Sen P, Audo I, Soumittra N, Zeitz C. Next-generation sequencing confirms the implication of SLC24A1 in autosomal-recessive congenital stationary night blindness. Clin Genet 2016; 89:690-9. [PMID: 26822852 DOI: 10.1111/cge.12746] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Revised: 01/25/2016] [Accepted: 01/25/2016] [Indexed: 01/17/2023]
Abstract
Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous retinal disorder which represents rod photoreceptor dysfunction or signal transmission defect from photoreceptors to adjacent bipolar cells. Patients displaying photoreceptor dysfunction show a Riggs-electroretinogram (ERG) while patients with a signal transmission defect show a Schubert-Bornschein ERG. The latter group is subdivided into complete or incomplete (ic) CSNB. Only few CSNB cases with Riggs-ERG and only one family with a disease-causing variant in SLC24A1 have been reported. Whole-exome sequencing (WES) in a previously diagnosed icCSNB patient identified a homozygous nonsense variant in SLC24A1. Indeed, re-investigation of the clinical data corrected the diagnosis to Riggs-form of CSNB. Targeted next-generation sequencing (NGS) identified compound heterozygous deletions and a homozygous missense variant in SLC24A1 in two other patients, respectively. ERG abnormalities varied in these three cases but all patients had normal visual acuity, no myopia or nystagmus, unlike in Schubert-Bornschein-type of CSNB. This confirms that SLC24A1 defects lead to CSNB and outlines phenotype/genotype correlations in CSNB subtypes. In case of unclear clinical characteristics, NGS techniques are helpful to clarify the diagnosis.
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Affiliation(s)
- M Neuillé
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - S Malaichamy
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - M Vadalà
- Ophthalmology Section, Department of Experimental Medicine and Clinical Neuroscience, University of Palermo, Palermo, Italy
| | - C Michiels
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - C Condroyer
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - R Sachidanandam
- Department of Optometry, Medical Research Foundation, Chennai, India
| | - S Srilekha
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - T Arokiasamy
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | | | - V Démontant
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
| | - J-A Sahel
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, UK.,Fondation Ophtalmologique Adolphe de Rothschild, Paris, France.,Académie des Sciences, Institut de France, Paris, France
| | - P Sen
- Department of Vitreo-Retinal Services, Medical Research Foundation, Chennai, India
| | - I Audo
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France.,CHNO des Quinze-Vingts, DHU Sight Restore, INSERM-DHOS CIC 1423, Paris, France.,Institute of Ophthalmology, University College of London, London, UK
| | - N Soumittra
- SN ONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - C Zeitz
- Sorbonne Universités, UPMC Univ Paris 06, INSERM, CNRS, Institut de la Vision, Paris, France
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Emery M, Nanchen N, Preitner F, Ibberson M, Roduit R. Biological Characterization of Gene Response to Insulin-Induced Hypoglycemia in Mouse Retina. PLoS One 2016; 11:e0150266. [PMID: 26918849 PMCID: PMC4769281 DOI: 10.1371/journal.pone.0150266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 02/11/2016] [Indexed: 12/31/2022] Open
Abstract
Glucose is the most important metabolic substrate of the retina and maintenance of normoglycemia is an essential challenge for diabetic patients. Chronic, exaggerated, glycemic excursions could lead to cardiovascular diseases, nephropathy, neuropathy and retinopathy. We recently showed that hypoglycemia induced retinal cell death in mouse via caspase 3 activation and glutathione (GSH) decrease. Ex vivo experiments in 661W photoreceptor cells confirmed the low-glucose induction of death via superoxide production and activation of caspase 3, which was concomitant with a decrease of GSH content. We evaluate herein retinal gene expression 4 h and 48 h after insulin-induced hypoglycemia. Microarray analysis demonstrated clusters of genes whose expression was modified by hypoglycemia and we discuss the potential implication of those genes in retinal cell death. In addition, we identify by gene set enrichment analysis, three important pathways, including lysosomal function, GSH metabolism and apoptotic pathways. Then we tested the effect of recurrent hypoglycemia (three successive 4h periods of hypoglycemia spaced by 48 h recovery) on retinal cell death. Interestingly, exposure to multiple hypoglycemic events prevented GSH decrease and retinal cell death, or adapted the retina to external stress by restoring GSH level comparable to control situation. We hypothesize that scavenger GSH is a key compound in this apoptotic process, and maintaining "normal" GSH level, as well as a strict glycemic control, represents a therapeutic challenge in order to avoid side effects of diabetes, especially diabetic retinopathy.
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Affiliation(s)
- Martine Emery
- IRO, Institute for Research in Ophthalmology, Sion, Switzerland
| | - Natacha Nanchen
- IRO, Institute for Research in Ophthalmology, Sion, Switzerland
| | - Frédéric Preitner
- Mouse Metabolic Evaluation Facility, Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Mark Ibberson
- Vital-IT Group, Swiss Institute of Bioinformatics, University of Lausanne, Lausanne, Switzerland
| | - Raphaël Roduit
- IRO, Institute for Research in Ophthalmology, Sion, Switzerland
- Department of Ophthalmology, University of Lausanne, Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, Lausanne, Switzerland
- * E-mail:
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Naeem MA, Gottsch ADH, Ullah I, Khan SN, Husnain T, Butt NH, Qazi ZA, Akram J, Riazuddin S, Ayyagari R, Hejtmancik JF, Riazuddin SA. Mutations in GRM6 identified in consanguineous Pakistani families with congenital stationary night blindness. Mol Vis 2015; 21:1261-71. [PMID: 26628857 PMCID: PMC4636350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 10/28/2015] [Indexed: 12/03/2022] Open
Abstract
PURPOSE This study was undertaken to investigate the causal mutations responsible for autosomal recessive congenital stationary night blindness (CSNB) in consanguineous Pakistani families. METHODS Two consanguineous families with multiple individuals manifesting symptoms of stationary night blindness were recruited. Affected individuals underwent a detailed ophthalmological examination, including fundus examination and electroretinography. Blood samples were collected and genomic DNA was extracted. Exclusion analyses were completed by genotyping closely spaced microsatellite markers, and two-point logarithm of odds (LOD) scores were calculated. All coding exons, along with the exon-intron boundaries of GRM6, were sequenced bidirectionally. RESULTS According to the medical history available to us, affected individuals in both families had experienced night blindness from the early years of their lives. Fundus photographs of affected individuals in both the families appeared normal, with no signs of attenuated arteries or bone spicule pigmentation. The scotopic electroretinogram (ERG) response were absent in all of the affected individuals, while the photopic measurements show reduced b-waves. During exclusion analyses, both families localized to a region on chromosome 5q that harbors GRM6, a gene previously associated with autosomal recessive CSNB. Bidirectional sequencing of GRM6 identified homozygous single base pair changes, specifically c.1336C>T (p.R446X) and c.2267G>A (p.G756D) in families PKRP170 and PKRP172, respectively. CONCLUSIONS We identified a novel nonsense and a previously reported missense mutation in GRM6 that were responsible for autosomal recessive CSNB in patients of Pakistani decent.
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Affiliation(s)
- Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | | | - Inayat Ullah
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Shaheen N. Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Tayyab Husnain
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Nadeem H. Butt
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
| | | | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan,Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan,National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Radha Ayyagari
- Shiley Eye Institute, University of California San Diego, La Jolla CA
| | - J. Fielding Hejtmancik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, National Institutes of Health, Bethesda MD
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore MD
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A Naturally Occurring Canine Model of Autosomal Recessive Congenital Stationary Night Blindness. PLoS One 2015; 10:e0137072. [PMID: 26368928 PMCID: PMC4569341 DOI: 10.1371/journal.pone.0137072] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2015] [Accepted: 08/12/2015] [Indexed: 11/20/2022] Open
Abstract
Congenital stationary night blindness (CSNB) is a non-progressive, clinically and genetically heterogeneous disease of impaired night vision. We report a naturally-occurring, stationary, autosomal recessive phenotype in beagle dogs with normal daylight vision but absent night vision. Affected dogs had normal retinas on clinical examination, but showed no detectable rod responses. They had “negative-type” mixed rod and cone responses in full-field ERGs. Their photopic long-flash ERGs had normal OFF-responses associated with severely reduced ON-responses. The phenotype is similar to the Schubert-Bornschein form of complete CSNB in humans. Homozygosity mapping ruled out most known CSNB candidates as well as CACNA2D4 and GNB3. Three remaining genes were excluded based on sequencing the open reading frame and intron-exon boundaries (RHO, NYX), causal to a different form of CSNB (RHO) or X-chromosome (NYX, CACNA1F) location. Among the genes expressed in the photoreceptors and their synaptic terminals, and mGluR6 cascade and modulators, reduced expression of GNAT1, CACNA2D4 and NYX was observed by qRT-PCR in both carrier (n = 2) and affected (n = 2) retinas whereas CACNA1F was down-regulated only in the affecteds. Retinal morphology revealed normal cellular layers and structure, and electron microscopy showed normal rod spherules and synaptic ribbons. No difference from normal was observed by immunohistochemistry (IHC) for antibodies labeling rods, cones and their presynaptic terminals. None of the retinas showed any sign of stress. Selected proteins of mGluR6 cascade and its modulators were examined by IHC and showed that PKCα weakly labeled the rod bipolar somata in the affected, but intensely labeled axonal terminals that appeared thickened and irregular. Dendritic terminals of ON-bipolar cells showed increased Goα labeling. Both PKCα and Goα labeled the more prominent bipolar dendrites that extended into the OPL in affected but not normal retinas. Interestingly, RGS11 showed no labeling in the affected retina. Our results indicate involvement of a yet unknown gene in this canine model of complete CSNB.
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Maranhao B, Biswas P, Gottsch ADH, Navani M, Naeem MA, Suk J, Chu J, Khan SN, Poleman R, Akram J, Riazuddin S, Lee P, Riazuddin SA, Hejtmancik JF, Ayyagari R. Investigating the Molecular Basis of Retinal Degeneration in a Familial Cohort of Pakistani Decent by Exome Sequencing. PLoS One 2015; 10:e0136561. [PMID: 26352687 PMCID: PMC4564165 DOI: 10.1371/journal.pone.0136561] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 08/04/2015] [Indexed: 11/18/2022] Open
Abstract
PURPOSE To define the molecular basis of retinal degeneration in consanguineous Pakistani pedigrees with early onset retinal degeneration. METHODS A cohort of 277 individuals representing 26 pedigrees from the Punjab province of Pakistan was analyzed. Exomes were captured with commercial kits and sequenced on an Illumina HiSeq 2500. Candidate variants were identified using standard tools and analyzed using exomeSuite to detect all potentially pathogenic changes in genes implicated in retinal degeneration. Segregation analysis was performed by dideoxy sequencing and novel variants were additionally investigated for their presence in ethnicity-matched controls. RESULTS We identified a total of nine causal mutations, including six novel variants in RPE65, LCA5, USH2A, CNGB1, FAM161A, CERKL and GUCY2D as the underlying cause of inherited retinal degenerations in 13 of 26 pedigrees. In addition to the causal variants, a total of 200 variants each observed in five or more unrelated pedigrees investigated in this study that were absent from the dbSNP, HapMap, 1000 Genomes, NHLBI ESP6500, and ExAC databases were identified, suggesting that they are common in, and unique to the Pakistani population. CONCLUSIONS We identified causal mutations associated with retinal degeneration in nearly half of the pedigrees investigated in this study through next generation whole exome sequencing. All novel variants detected in this study through exome sequencing have been cataloged providing a reference database of variants common in, and unique to the Pakistani population.
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Affiliation(s)
- Bruno Maranhao
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
| | - Pooja Biswas
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
| | - Alexander D. H. Gottsch
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Mili Navani
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
| | - Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - John Suk
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
| | - Justin Chu
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
| | - Sheen N. Khan
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - Rachel Poleman
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
| | - Javed Akram
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
- National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Sheikh Riazuddin
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
- Allama Iqbal Medical College, University of Health Sciences, Lahore, Pakistan
- National Centre for Genetic Diseases, Shaheed Zulfiqar Ali Bhutto Medical University, Islamabad, Pakistan
| | - Pauline Lee
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
| | - S. Amer Riazuddin
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - J. Fielding Hejtmancik
- OGVF branch, National Eye Institute, NIH, Bethesda, MD, United States of America
- * E-mail: (RA); (JFH)
| | - Radha Ayyagari
- Department of Ophthalmology, University of California La Jolla, La Jolla, CA, United States of America
- * E-mail: (RA); (JFH)
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Vinberg F, Wang T, Molday RS, Chen J, Kefalov VJ. A new mouse model for stationary night blindness with mutant Slc24a1 explains the pathophysiology of the associated human disease. Hum Mol Genet 2015; 24:5915-29. [PMID: 26246500 DOI: 10.1093/hmg/ddv319] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 07/31/2015] [Indexed: 11/12/2022] Open
Abstract
Mutations that affect calcium homeostasis (Ca(2+)) in rod photoreceptors are linked to retinal degeneration and visual disorders such as retinitis pigmentosa and congenital stationary night blindness (CSNB). It is thought that the concentration of Ca(2+) in rod outer segments is controlled by a dynamic balance between influx via cGMP-gated (CNG) channels and extrusion via Na(+)/Ca(2+), K(+) exchangers (NCKX1). The extrusion-driven lowering of rod [Ca(2+)]i following light exposure controls their light adaptation and response termination. Mutant NCKX1 has been linked to autosomal-recessive stationary night blindness. However, whether NCKX1 contributes to light adaptation has not been directly tested and the mechanisms by which human NCKX1 mutations cause night blindness are not understood. Here, we report that the deletion of NCKX1 in mice results in malformed outer segment disks, suppressed expression and function of rod CNG channels and a subsequent 100-fold reduction in rod responses, while preserving normal cone responses. The compensating loss of CNG channel function in the absence of NCKX1-mediated Ca(2+) extrusion may prevent toxic Ca(2+) buildup and provides an explanation for the stationary nature of the associated disorder in humans. Surprisingly, the lack of NCKX1 did not compromise rod background light adaptation, suggesting additional Ca(2+)-extruding mechanisms exist in these cells.
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Affiliation(s)
- Frans Vinberg
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA
| | - Tian Wang
- Cell and Neurobiology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, USA and
| | - Robert S Molday
- Biochemistry/Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Jeannie Chen
- Cell and Neurobiology, Zilkha Neurogenetic Institute, University of Southern California, Los Angeles, CA, USA and
| | - Vladimir J Kefalov
- Ophthalmology and Visual Sciences, Washington University School of Medicine, St. Louis, MO, USA,
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Abstract
Despite remarkable progress in the identification of mutations that drive genetic disorders, progress in understanding the effect of genetic background on the penetrance and expressivity of causal alleles has been modest, in part because of the methodological challenges in identifying genetic modifiers. Nonetheless, the progressive discovery of modifier alleles has improved both our interpretative ability and our analytical tools to dissect such phenomena. In this review, we analyze the genetic properties and behaviors of modifiers as derived from studies in patient populations and model organisms and we highlight conceptual and technological tools used to overcome some of the challenges inherent in modifier mapping and cloning. Finally, we discuss how the identification of these modifiers has facilitated the elucidation of biological pathways and holds the potential to improve the clinical predictive value of primary causal mutations and to develop novel drug targets.
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Affiliation(s)
- Maria Kousi
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27710
| | - Nicholas Katsanis
- Center for Human Disease Modeling, Duke University, Durham, North Carolina 27710
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Congenital stationary night blindness: An analysis and update of genotype–phenotype correlations and pathogenic mechanisms. Prog Retin Eye Res 2015; 45:58-110. [DOI: 10.1016/j.preteyeres.2014.09.001] [Citation(s) in RCA: 207] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Revised: 09/25/2014] [Accepted: 09/30/2014] [Indexed: 01/18/2023]
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Targeted next generation sequencing identifies novel mutations in RP1 as a relatively common cause of autosomal recessive rod-cone dystrophy. BIOMED RESEARCH INTERNATIONAL 2015; 2015:485624. [PMID: 25692139 PMCID: PMC4307388 DOI: 10.1155/2015/485624] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 07/10/2014] [Indexed: 01/01/2023]
Abstract
We report ophthalmic and genetic findings in families with autosomal recessive rod-cone dystrophy (arRCD) and RP1 mutations. Detailed ophthalmic examination was performed in 242 sporadic and arRCD subjects. Genomic DNA was investigated using our customized next generation sequencing panel targeting up to 123 genes implicated in inherited retinal disorders. Stringent filtering coupled with Sanger sequencing and followed by cosegregation analysis was performed to confirm biallelism and the implication of the most likely disease causing variants. Sequencing identified 9 RP1 mutations in 7 index cases. Eight of the mutations were novel, and all cosegregated with severe arRCD phenotype, found associated with additional macular changes. Among the identified mutations, 4 belong to a region, previously associated with arRCD, and 5 others in a region previously associated with adRCD. Our prevalence studies showed that RP1 mutations account for up to 2.5% of arRCD. These results point out for the necessity of sequencing RP1 when genetically investigating sporadic and arRCD. It further highlights the interest of unbiased sequencing technique, which allows investigating the implication of the same gene in different modes of inheritance. Finally, it reports that different regions of RP1 can also lead to arRCD.
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Wang S, Choi M, Richardson AS, Reid BM, Seymen F, Yildirim M, Tuna E, Gençay K, Simmer JP, Hu JC. STIM1 and SLC24A4 Are Critical for Enamel Maturation. J Dent Res 2014; 93:94S-100S. [PMID: 24621671 PMCID: PMC4107542 DOI: 10.1177/0022034514527971] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Dental enamel formation depends upon the transcellular transport of Ca(2+) by ameloblasts, but little is known about the molecular mechanism, or even if the same process is operative during the secretory and maturation stages of amelogenesis. Identifying mutations in genes involved in Ca(2+) homeostasis that cause inherited enamel defects can provide insights into the molecular participants and potential mechanisms of Ca(2+) handling by ameloblasts. Stromal Interaction Molecule 1 (STIM1) is an ER transmembrane protein that activates membrane-specific Ca(2+) influx in response to the depletion of ER Ca(2+) stores. Solute carrier family 24, member 4 (SLC24A4), is a Na(+)/K(+)/Ca(2+) transporter that exchanges intracellular Ca(2+) and K(+) for extracellular Na(+). We identified a proband with syndromic hypomaturation enamel defects caused by a homozygous C to T transition (g.232598C>T c.1276C>T p.Arg426Cys) in STIM1, and a proband with isolated hypomaturation enamel defects caused by a homozygous C to T transition (g.124552C>T; c.437C>T; p.Ala146Val) in SLC24A4. Immunohistochemistry of developing mouse molars and incisors showed positive STIM1 and SLC24A4 signal specifically in maturation-stage ameloblasts. We conclude that enamel maturation is dependent upon STIM1 and SLC24A4 function, and that there are important differences in the Ca(2+) transcellular transport systems used by secretory- and maturation-stage ameloblasts.
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Affiliation(s)
- S Wang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA Oral Health Sciences Program, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI, USA
| | - M Choi
- Department of Biomedical Sciences, College of Medicine, Seoul National University, 275-1 Yongon-dong, Chongno-gu, Seoul 110-768, Korea Department of Genetics, Howard Hughes Medical Institute, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, USA
| | - A S Richardson
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA
| | - B M Reid
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA
| | - F Seymen
- Department of Pedodontics, Istanbul University, Faculty of Dentistry, Istanbul, Turkey
| | - M Yildirim
- Department of Pedodontics, Istanbul University, Faculty of Dentistry, Istanbul, Turkey
| | - E Tuna
- Department of Pedodontics, Istanbul University, Faculty of Dentistry, Istanbul, Turkey
| | - K Gençay
- Department of Pedodontics, Istanbul University, Faculty of Dentistry, Istanbul, Turkey
| | - J P Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA
| | - J C Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1210 Eisenhower Place, Ann Arbor, MI, USA
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Emerling CA, Springer MS. Eyes underground: regression of visual protein networks in subterranean mammals. Mol Phylogenet Evol 2014; 78:260-70. [PMID: 24859681 DOI: 10.1016/j.ympev.2014.05.016] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2014] [Revised: 04/26/2014] [Accepted: 05/05/2014] [Indexed: 11/26/2022]
Abstract
Regressive evolution involves the degeneration of formerly useful structures in a lineage over time, and may be accompanied by the molecular decay of phenotype-specific genes. The mammalian eye has repeatedly undergone degeneration in taxa that occupy dim-light environments including subterranean habitats. Here we assess whether a decrease in the amount of light that reaches the retina is associated with increased regression of retinal genes, whether the phototransduction and visual cycle pathways degrade in a predictable pattern, and if the timing of retinal gene loss is associated with the entrance of mammalian lineages into subterranean environments. Sequence data were obtained from the publically available genomes of the Cape golden mole (Chrysochloris asiatica), naked mole-rat (Heterocephalus glaber) and star-nosed mole (Condylura cristata) for 65 genes associated with phototransduction, the visual cycle, and other retinal functions. Gene sequences were inspected for inactivating mutations and, when present, pseudogene sequences were compared to sequences from subaerial outgroup species. To test whether retinal degeneration is correlated with historical entrances into subterranean environments, estimated dates of retinal gene inactivation were compared to the fossil record and phylogenetic inferences of ancestral fossoriality. Our results show that (1) lower levels of light available to the retina correspond with an increase in the number of retinal pseudogenes, (2) retinal protein networks generally degrade in a predictable manner, although the extensive loss of cone phototransduction genes in Heterocephalus raises further questions regarding SWS1-cone monochromacy versus functional rod monochromacy in this species, and (3) inactivation dates of retinal genes usually post-date inferred entrances into subterranean habitats.
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Affiliation(s)
- Christopher A Emerling
- Department of Biology, University of California Riverside, 900 University Ave, Riverside, CA 92521, United States.
| | - Mark S Springer
- Department of Biology, University of California Riverside, 900 University Ave, Riverside, CA 92521, United States.
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Malaichamy S, Sen P, Sachidanandam R, Arokiasamy T, Lancelot ME, Audo I, Zeitz C, Soumittra N. Molecular profiling of complete congenital stationary night blindness: a pilot study on an Indian cohort. Mol Vis 2014; 20:341-51. [PMID: 24715752 PMCID: PMC3962728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 03/18/2014] [Indexed: 10/27/2022] Open
Abstract
PURPOSE Congenital stationary night blindness (CSNB) is a non-progressive retinal disorder that shows genetic and clinical heterogeneity. CSNB is inherited as an autosomal recessive, autosomal dominant, or X-linked recessive trait and shows a good genotype-phenotype correlation. Clinically, CSNB is classified as the Riggs type and the Schubert-Bornschein type. The latter form is further sub-classified into complete and incomplete forms based on specific waveforms on the electroretinogram (ERG). There are no molecular genetic data for CSNB in the Indian population. Therefore, we present for the first time molecular profiling of eight families with complete CSNB (cCSNB). METHODS The index patients and their other affected family members were comprehensively evaluated for the phenotype, including complete ophthalmic evaluation, ERG, fundus autofluorescence, optical coherence tomography, and color vision test. The known gene defects for cCSNB, LRIT3, TRPM1, GRM6, GPR179, and NYX, were screened by PCR direct sequencing. Bioinformatic analyses were performed using SIFT and PolyPhen for the identified missense mutations. RESULTS All eight affected index patients and affected family members were identified as having cCSNB based on their ERG waveforms. Mutations in the TRPM1 gene were identified in six index patients. The two remaining index patients each carried a GPR179 and GRM6 mutation. Seven of the patients revealed homozygous mutations, while one patient showed a compound heterozygous mutation. Six of the eight mutations identified are novel. CONCLUSIONS This is the first report on molecular profiling of candidate genes in CSNB in an Indian cohort. As shown for other cohorts, TRPM1 seems to be a major gene defect in patients with cCSNB in India.
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Affiliation(s)
- Sivasankar Malaichamy
- SNONGC department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - Parveen Sen
- Department of Vitreo-Retinal Services, Medical Research Foundation, Chennai, India
| | | | - Tharigopala Arokiasamy
- SNONGC department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
| | - Marie Elise Lancelot
- INSERM, U968, Paris, F-75012, France,CNRS, UMR_7210, Paris, F-75012, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, F-75012, France
| | - Isabelle Audo
- INSERM, U968, Paris, F-75012, France,CNRS, UMR_7210, Paris, F-75012, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, F-75012, France,Centre Hospitalier National d'Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 503, Paris F-75012, France,UCL-Institute of Ophthalmology, 11-43 Bath Street, London, EC1V 9EL, UK
| | - Christina Zeitz
- INSERM, U968, Paris, F-75012, France,CNRS, UMR_7210, Paris, F-75012, France,Sorbonne Universités, UPMC Univ Paris 06, UMR_S 968, Institut de la Vision, Paris, F-75012, France
| | - Nagasamy Soumittra
- SNONGC department of Genetics and Molecular Biology, Vision Research Foundation, Chennai, India
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Khan MI, Azam M, Ajmal M, Collin RWJ, den Hollander AI, Cremers FPM, Qamar R. The molecular basis of retinal dystrophies in pakistan. Genes (Basel) 2014; 5:176-95. [PMID: 24705292 PMCID: PMC3978518 DOI: 10.3390/genes5010176] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2014] [Revised: 02/14/2014] [Accepted: 02/14/2014] [Indexed: 12/23/2022] Open
Abstract
The customary consanguineous nuptials in Pakistan underlie the frequent occurrence of autosomal recessive inherited disorders, including retinal dystrophy (RD). In many studies, homozygosity mapping has been shown to be successful in mapping susceptibility loci for autosomal recessive inherited disease. RDs are the most frequent cause of inherited blindness worldwide. To date there is no comprehensive genetic overview of different RDs in Pakistan. In this review, genetic data of syndromic and non-syndromic RD families from Pakistan has been collected. Out of the 132 genes known to be involved in non-syndromic RD, 35 different genes have been reported to be mutated in families of Pakistani origin. In the Pakistani RD families 90% of the mutations causing non-syndromic RD and all mutations causing syndromic forms of the disease have not been reported in other populations. Based on the current inventory of all Pakistani RD-associated gene defects, a cost-efficient allele-specific analysis of 11 RD-associated variants is proposed, which may capture up to 35% of the genetic causes of retinal dystrophy in Pakistan.
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Affiliation(s)
- Muhammad Imran Khan
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Maleeha Azam
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Muhammad Ajmal
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen 6500 HB, The Netherlands.
| | - Anneke I den Hollander
- Department of Human Genetics, Radboud University Medical Center, Nijmegen 6500 HB, The Netherlands.
| | - Frans P M Cremers
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
| | - Raheel Qamar
- Department of Biosciences, Faculty of Science, COMSATS Institute of Information Technology, Islamabad 45600, Pakistan.
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Schnetkamp PPM. The SLC24 gene family of Na⁺/Ca²⁺-K⁺ exchangers: from sight and smell to memory consolidation and skin pigmentation. Mol Aspects Med 2013; 34:455-64. [PMID: 23506883 DOI: 10.1016/j.mam.2012.07.008] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Accepted: 03/09/2012] [Indexed: 01/28/2023]
Abstract
Members of the SLC24 gene family encode K(+)-dependent Na(+)/Ca(2+) exchangers (NCKX) that utilize both the inward Na(+) and outward K(+) gradients to extrude Ca(2+) from cells. There are five human SLC24 genes that play a role in biological process as diverse as vision in retinal rod and cone photoreceptors, olfaction, skin pigmentation and at least three of the five genes are also widely expressed in the brain. Here I review the functional, physiological and structural features of NCKX proteins that have emerged in the past few years.
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Affiliation(s)
- Paul P M Schnetkamp
- Department of Physiology & Pharmacology, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, 3330 Hospital Dr. NW, Calgary, Canada AB T2N 4N1.
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Cheng CL, Molday RS. Changes in gene expression associated with retinal degeneration in the rd3 mouse. Mol Vis 2013; 19:955-69. [PMID: 23687432 PMCID: PMC3654844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2012] [Accepted: 05/04/2013] [Indexed: 11/04/2022] Open
Abstract
PURPOSE To identify and characterize changes in gene expression associated with photoreceptor degeneration in the rd3 mouse model of Leber congenital amaurosis (LCA) type 12. METHODS Global genome expression profiling using microarray technology was performed on total RNA extracts from rd3 and wild-type control mouse retinas at postnatal day 21. Quantitative PCR analysis of selected transcripts was performed to validate the microarray results. RESULTS Functional annotation of differentially regulated genes in the rd3 mouse defined key canonical pathways, including phototransduction, glycerophospholipid metabolism, tumor necrosis factor receptor 1 signaling, and endothelin signaling. Overall, 1,140 of approximately 55,800 transcripts were differentially represented. In particular, a large percentage of the upregulated transcripts encode proteins involved in the immune response; whereas the downregulated transcripts encode proteins involved in phototransduction and lipid metabolism. CONCLUSIONS This analysis has elucidated several candidate genes and pathways, thus providing insight into the pathogenic mechanisms underlying the photoreceptor degeneration in the rd3 mouse retina and indicating directions for future studies.
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Zeitz C, Jacobson S, Hamel C, Bujakowska K, Neuillé M, Orhan E, Zanlonghi X, Lancelot ME, Michiels C, Schwartz S, Bocquet B, Antonio A, Audier C, Letexier M, Saraiva JP, Luu T, Sennlaub F, Nguyen H, Poch O, Dollfus H, Lecompte O, Kohl S, Sahel JA, Bhattacharya S, Audo I, Audo I. Whole-exome sequencing identifies LRIT3 mutations as a cause of autosomal-recessive complete congenital stationary night blindness. Am J Hum Genet 2013; 92:67-75. [PMID: 23246293 DOI: 10.1016/j.ajhg.2012.10.023] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 09/12/2012] [Accepted: 10/25/2012] [Indexed: 11/25/2022] Open
Abstract
Congenital stationary night blindness (CSNB) is a clinically and genetically heterogeneous retinal disorder. Two forms can be distinguished clinically: complete CSNB (cCSNB) and incomplete CSNB. Individuals with cCSNB have visual impairment under low-light conditions and show a characteristic electroretinogram (ERG). The b-wave amplitude is severely reduced in the dark-adapted state of the ERG, representing abnormal function of ON bipolar cells. Furthermore, individuals with cCSNB can show other ocular features such as nystagmus, myopia, and strabismus and can have reduced visual acuity and abnormalities of the cone ERG waveform. The mode of inheritance of this form can be X-linked or autosomal recessive, and the dysfunction of four genes (NYX, GRM6, TRPM1, and GPR179) has been described so far. Whole-exome sequencing in one simplex cCSNB case lacking mutations in the known genes led to the identification of a missense mutation (c.983G>A [p.Cys328Tyr]) and a nonsense mutation (c.1318C>T [p.Arg440(∗)]) in LRIT3, encoding leucine-rich-repeat (LRR), immunoglobulin-like, and transmembrane-domain 3 (LRIT3). Subsequent Sanger sequencing of 89 individuals with CSNB identified another cCSNB case harboring a nonsense mutation (c.1151C>G [p.Ser384(∗)]) and a deletion predicted to lead to a premature stop codon (c.1538_1539del [p.Ser513Cysfs(∗)59]) in the same gene. Human LRIT3 antibody staining revealed in the outer plexiform layer of the human retina a punctate-labeling pattern resembling the dendritic tips of bipolar cells; similar patterns have been observed for other proteins implicated in cCSNB. The exact role of this LRR protein in cCSNB remains to be elucidated.
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Arrayed primer extension microarray for the analysis of genes associated with congenital stationary night blindness. Methods Mol Biol 2013; 963:319-26. [PMID: 23296619 DOI: 10.1007/978-1-62703-230-8_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Arrayed primer extension (APEX) is a microarray-based genotyping method that enables to simultaneously analyze hundreds of known mutations in the genome. APEX-based microarrays are successfully used for molecular diagnostics of various genetic disorders. Congenital stationary night blindness (CSNB) is a rare retinal disease caused by mutations in genes involved in phototransduction cascade and signaling from photoreceptors to adjacent neurons in the retina. As CSNB is clinically and genetically heterogeneous, the identification of the underlying cause of the disease can be challenging. In this chapter, we describe an APEX-based method for the analysis of genes associated with CSNB.
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Abstract
Photoreceptors are exquisitely adapted to transform light stimuli into electrical signals that modulate neurotransmitter release. These cells are organized into several compartments including the unique outer segment (OS). Its whole function is to absorb light and transduce this signal into a change of membrane potential. Another compartment is the inner segment where much of metabolism and regulation of membrane potential takes place and that connects the OS and synapse. The synapse is the compartment where changes in membrane potentials are relayed to other neurons in the retina via release of neurotransmitter. The composition of the plasma membrane surrounding these compartments varies to accommodate their specific functions. In this chapter, we discuss the organization of the plasma membrane emphasizing the protein composition of each region as it relates to visual signaling. We also point out examples where mutations in these proteins cause visual impairment.
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Affiliation(s)
- Sheila A Baker
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA.
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Wang Q, Gao Y, Li S, Guo X, Zhang Q. Mutation screening of TRPM1, GRM6, NYX and CACNA1F genes in patients with congenital stationary night blindness. Int J Mol Med 2012; 30:521-6. [PMID: 22735794 DOI: 10.3892/ijmm.2012.1039] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 02/28/2012] [Indexed: 11/06/2022] Open
Abstract
The aim of this study was to identify mutations in the TRPM1, GRM6, NYX and CACNA1F genes in patients with congenital stationary night blindness (CSNB). Twenty-four unrelated patients with CSNB were ascertained. Sanger sequencing was used to analyze the coding exons and adjacent intronic regions of TRPM1, GRM6, NYX and CACNA1F. Six mutations were identified in six unrelated patients, including five novel and one known. Of the six, three novel hemizygous mutations, c.92G>A (p.Cys31Tyr), c.149G>C (p.Ary50Pro), and c.[272T>A;1429G>C] (p.[Leu91Gln;Gly477Arg]), were found in NYX in three patients, respectively. A novel c.[1984_1986delCTC;3001G>A] (p.[Leu662del;Gly1001Arg]) mutation was detected in CACNA1F in one patient. One novel and one known heterozygous variation, c.1267T>C (p.Cys423Arg) and c.1537G>A (p.Val513Met), were detected in GRM6 in two patients, respectively. No variations were found in TRPM1. The results expand the mutation spectrum of NYX, CACNA1F and GRM6. They also suggest that NYX mutations are a common cause of CSNB.
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Affiliation(s)
- Qin Wang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, P.R. China
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Naeem MA, Chavali VRM, Ali S, Iqbal M, Riazuddin S, Khan SN, Husnain T, Sieving PA, Ayyagari R, Riazuddin S, Hejtmancik JF, Riazuddin SA. GNAT1 associated with autosomal recessive congenital stationary night blindness. Invest Ophthalmol Vis Sci 2012; 53:1353-61. [PMID: 22190596 DOI: 10.1167/iovs.11-8026] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE Congenital stationary night blindness is a nonprogressive retinal disorder manifesting as impaired night vision and is generally associated with other ocular symptoms, such as nystagmus, myopia, and strabismus. This study was conducted to further investigate the genetic basis of CSNB in a consanguineous Pakistani family. METHODS A consanguineous family with multiple individuals manifesting cardinal symptoms of congenital stationary night blindness was ascertained. All family members underwent detailed ophthalmic examination, including fundus photographic examination and electroretinography. Blood samples were collected and genomic DNA was extracted. Exclusion and genome-wide linkage analyses were completed and two-point LOD scores were calculated. Bidirectional sequencing of GNAT1 was completed, and quantitative expression of Gnat1 transcript levels were investigated in ocular tissues at different postnatal intervals. RESULTS The results of ophthalmic examinations were suggestive of early-onset stationary night blindness with no extraocular anomalies. The genome-wide scan localized the critical interval to chromosome 3, region p22.1-p14.3, with maximum two-point LOD scores of 3.09 at θ = 0, flanked by markers D3S3522 and D3S1289. Subsequently, a missense mutation in GNAT1, p.D129G, was identified, which segregated within the family, consistent with an autosomal recessive mode of inheritance, and was not present in 192 ethnically matched control chromosomes. Expression analysis suggested that Gnat1 is expressed at approximately postnatal day (P)7 and is predominantly expressed in the retina. CONCLUSIONS These data suggest that a homozygous missense mutation in GNAT1 is associated with autosomal recessive stationary night blindness.
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Affiliation(s)
- Muhammad Asif Naeem
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
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