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Munir A, Afsar S, Rehman AU. A systematic review of inherited retinal dystrophies in Pakistan: updates from 1999 to April 2023. BMC Ophthalmol 2024; 24:55. [PMID: 38317096 PMCID: PMC10840256 DOI: 10.1186/s12886-024-03319-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 01/19/2024] [Indexed: 02/07/2024] Open
Abstract
BACKGROUND Inherited retinal degenerations (IRDs) are a group of rare genetic conditions affecting retina of the eye that range in prevalence from 1 in 2000 to 1 in 4000 people globally. This review is based on a retrospective analysis of research articles reporting IRDs associated genetic findings in Pakistani families between 1999 and April 2023. METHODS Articles were retrieved through survey of online sources, notably, PubMed, Google Scholar, and Web of Science. Following a stringent selection criterion, a total of 126 research articles and conference abstracts were considered. All reported variants were cross-checked and validated for their correct genomic nomenclature using different online resources/databases, and their pathogenicity scores were explained as per ACMG guidelines. RESULTS A total of 277 unique sequence variants in 87 distinct genes, previously known to cause IRDs, were uncovered. In around 70% cases, parents of the index patient were consanguineously married, and approximately 88.81% of the detected variants were found in a homozygous state. Overall, more than 95% of the IRDs cases were recessively inherited. Missense variants were predominant (41.88%), followed by Indels/frameshift (26.35%), nonsense (19.13%), splice site (12.27%) and synonymous change (0.36%). Non-syndromic IRDs were significantly higher than syndromic IRDs (77.32% vs. 22.68%). Retinitis pigmentosa (RP) was the most frequently observed IRD followed by Leber's congenital amaurosis (LCA). Altogether, mutations in PDE6A gene was the leading cause of IRDs in Pakistani families followed by mutations in TULP1 gene. CONCLUSION In summary, Pakistani families are notable in expressing recessively inherited monogenic disorders including IRDs likely due to the highest prevalence of consanguinity in the country that leads to expression of rare pathogenic variants in homozygous state.
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Affiliation(s)
- Asad Munir
- Department of Zoology, Faculty of Biological and Health Sciences, Hazara University, Mansehra, 21300, Khyber Pakhtunkhwa, Pakistan
| | - Salma Afsar
- Department of Zoology, Faculty of Biological and Health Sciences, Hazara University, Mansehra, 21300, Khyber Pakhtunkhwa, Pakistan
| | - Atta Ur Rehman
- Department of Zoology, Faculty of Biological and Health Sciences, Hazara University, Mansehra, 21300, Khyber Pakhtunkhwa, Pakistan.
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Yang TH, Kang EYC, Lin PH, Wu PL, Sachs JA, Wang NK. The Value of Electroretinography in Identifying Candidate Genes for Inherited Retinal Dystrophies: A Diagnostic Guide. Diagnostics (Basel) 2023; 13:3041. [PMID: 37835784 PMCID: PMC10572658 DOI: 10.3390/diagnostics13193041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2023] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 10/15/2023] Open
Abstract
Inherited retinal dystrophies (IRDs) are a group of heterogeneous diseases caused by genetic mutations that specifically affect the function of the rod, cone, or bipolar cells in the retina. Electroretinography (ERG) is a diagnostic tool that measures the electrical activity of the retina in response to light stimuli, and it can help to determine the function of these cells. A normal ERG response consists of two waves, the a-wave and the b-wave, which reflect the activity of the photoreceptor cells and the bipolar and Muller cells, respectively. Despite the growing availability of next-generation sequencing (NGS) technology, identifying the precise genetic mutation causing an IRD can be challenging and costly. However, certain types of IRDs present with unique ERG features that can help guide genetic testing. By combining these ERG findings with other clinical information, such as on family history and retinal imaging, physicians can effectively narrow down the list of candidate genes to be sequenced, thereby reducing the cost of genetic testing. This review article focuses on certain types of IRDs with unique ERG features. We will discuss the pathophysiology and clinical presentation of, and ERG findings on, these disorders, emphasizing the unique role ERG plays in their diagnosis and genetic testing.
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Affiliation(s)
- Tsai-Hsuan Yang
- Department of Education, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 33305, Taiwan;
- College of Medicine, National Yang Ming Chiao Tung University, Taipei 11217, Taiwan
| | - Eugene Yu-Chuan Kang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 33305, Taiwan;
- College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Graduate Institute of Clinical Medical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Pei-Hsuan Lin
- National Taiwan University Hospital, Yunlin 640203, Taiwan;
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY 10032, USA; (P.-L.W.); (J.A.S.)
| | - Pei-Liang Wu
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY 10032, USA; (P.-L.W.); (J.A.S.)
- Department of Medicine, National Taiwan University, Taipei 10617, Taiwan
| | - Jacob Aaron Sachs
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY 10032, USA; (P.-L.W.); (J.A.S.)
- College of Arts and Sciences, University of Miami, Coral Gables, FL 33146, USA
| | - Nan-Kai Wang
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan 33305, Taiwan;
- College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
- Department of Ophthalmology, Edward S. Harkness Eye Institute, Columbia University Irving Medical Center, Columbia University, New York, NY 10032, USA; (P.-L.W.); (J.A.S.)
- Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
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3
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Martins-da-Silva A, Baroni M, Salomão KB, das Chagas PF, Bonfim-Silva R, Geron L, Cruzeiro GAV, da Silva WA, Corrêa CAP, Carlotti CG, de Paula Queiroz RG, Marie SKN, Brandalise SR, Yunes JA, Scrideli CA, Valera ET, Tone LG. Clinical Prognostic Implications of Wnt Hub Genes Expression in Medulloblastoma. Cell Mol Neurobiol 2023; 43:813-826. [PMID: 35366170 DOI: 10.1007/s10571-022-01217-4] [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: 07/13/2021] [Accepted: 03/22/2022] [Indexed: 11/03/2022]
Abstract
Medulloblastoma is the most common type of pediatric malignant primary brain tumor, and about one-third of patients die due to disease recurrence and most survivors suffer from long-term side effects. MB is clinically, genetically, and epigenetically heterogeneous and subdivided into at least four molecular subgroups: WNT, SHH, Group 3, and Group 4. We evaluated common differentially expressed genes between a Brazilian RNA-seq GSE181293 dataset and microarray GSE85217 dataset cohort of pediatric MB samples using bioinformatics methodology in order to identify hub genes of the molecular subgroups based on PPI network construction, survival and functional analysis. The main finding was the identification of five hub genes from the WNT subgroup that are tumor suppressors, and whose lower expression is related to a worse prognosis for MB patients. Furthermore, the common genes correlated with the five tumor suppressors participate in important pathways and processes for tumor initiation and progression, as well as development and differentiation, and some of them control cell stemness and pluripotency. These genes have not yet been studied within the context of MB, representing new important elements for investigation in the search for therapeutic targets, prognostic markers or for understanding of MB biology.
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Affiliation(s)
- Andrea Martins-da-Silva
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil.
| | - Mirella Baroni
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Karina Bezerra Salomão
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Pablo Ferreira das Chagas
- Department of Genetics, Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Ricardo Bonfim-Silva
- Department of Surgery and Anatomy, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Lenisa Geron
- Department of Genetics, Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Gustavo Alencastro Veiga Cruzeiro
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil.,Department of Pediatric Oncology, Harvard Medical School - Dana-Farber Cancer Institute, Boston, MA, USA
| | - Wilson Araújo da Silva
- Department of Genetics, Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Carolina Alves Pereira Corrêa
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Carlos Gilberto Carlotti
- Department of Surgery and Anatomy, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Rosane Gomes de Paula Queiroz
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | | | | | | | - Carlos Alberto Scrideli
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil.,Department of Genetics, Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Elvis Terci Valera
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
| | - Luiz Gonzaga Tone
- Department of Pediatrics, University Hospital - Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil.,Department of Genetics, Ribeirão Preto Medical School - University of São Paulo, Ribeirão Preto, Brazil
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Congenital Stationary Night Blindness: Clinical and Genetic Features. Int J Mol Sci 2022; 23:ijms232314965. [PMID: 36499293 PMCID: PMC9740538 DOI: 10.3390/ijms232314965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 10/22/2022] [Accepted: 10/29/2022] [Indexed: 12/03/2022] Open
Abstract
Congenital stationary night blindness (CSNB) is an inherited retinal disease (IRD) that causes night blindness in childhood with heterogeneous genetic, electrophysical, and clinical characteristics. The development of sequencing technologies and gene therapy have increased the ease and urgency of diagnosing IRDs. This study describes seven Taiwanese patients from six unrelated families examined at a tertiary referral center, diagnosed with CSNB, and confirmed by genetic testing. Complete ophthalmic exams included best corrected visual acuity, retinal imaging, and an electroretinogram. The effects of identified novel variants were predicted using clinical details, protein prediction tools, and conservation scores. One patient had an autosomal dominant CSNB with a RHO variant; five patients had complete CSNB with variants in GRM6, TRPM1, and NYX; and one patient had incomplete CSNB with variants in CACNA1F. The patients had Riggs and Schubert-Bornschein types of CSNB with autosomal dominant, autosomal recessive, and X-linked inheritance patterns. This is the first report of CSNB patients in Taiwan with confirmed genetic testing, providing novel perspectives on molecular etiology and genotype-phenotype correlation of CSNB. Particularly, variants in TRPM1, NYX, and CACNA1F in our patient cohort have not previously been described, although their clinical significance needs further study. Additional study is needed for the genotype-phenotype correlation of different mutations causing CSNB. In addition to genetic etiology, the future of gene therapy for CSNB patients is reviewed and discussed.
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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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6
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Matsushima N, Miyashita H, Kretsinger RH. Sequence features, structure, ligand interaction, and diseases in small leucine rich repeat proteoglycans. J Cell Commun Signal 2021; 15:519-531. [PMID: 33860400 DOI: 10.1007/s12079-021-00616-4] [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: 02/13/2021] [Accepted: 03/25/2021] [Indexed: 12/26/2022] Open
Abstract
Small leucine rich repeat proteoglycans (SLRPs) are a group of active components of the extracellular matrix in all tissues. SLRPs bind to collagens and regulate collagen fibril growth and fibril organization. SLRPs also interact with various cytokines and extracellular compounds, which lead to various biological functions such cell adhesion and signaling, proliferation, and differentiation. Mutations in SLRP genes are associated with human diseases. Now crystal structures of five SLRPs are available. We describe some features of amino acid sequence and structures of SLRPs. We also review ligand interactions and then discuss the interaction surfaces. Furthermore, we map mutations associated with human diseases and discuss possible effects on structures by the mutations.
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Affiliation(s)
- Norio Matsushima
- Division of Bioinformatics, Institute of Tandem Repeats, Noboribetsu, 059-0464, Japan.
- Center for Medical Education, Sapporo Medical University, Sapporo, 060-8556, Japan.
| | - Hiroki Miyashita
- Division of Bioinformatics, Institute of Tandem Repeats, Noboribetsu, 059-0464, Japan
- Hokubu Rinsho Co., Ltd, Sapporo, 060⎼0061, Japan
| | - Robert H Kretsinger
- Department of Biology, University of Virginia, Charlottesville, VA, 22904, USA
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Kobal N, Krašovec T, Šuštar M, Volk M, Peterlin B, Hawlina M, Fakin A. Stationary and Progressive Phenotypes Caused by the p.G90D Mutation in Rhodopsin Gene. Int J Mol Sci 2021; 22:ijms22042133. [PMID: 33669941 PMCID: PMC7924842 DOI: 10.3390/ijms22042133] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 12/30/2022] Open
Abstract
Mutations in rhodopsin gene (RHO) are a frequent cause of retinitis pigmentosa (RP) and less often, congenital stationary night blindness (CSNB). Mutation p.G90D has previously been associated with CSNB based on the examination of one family. This study screened 60 patients. Out of these 60 patients, 32 were affected and a full characterization was conducted in 15 patients. We described the clinical characteristics of these 15 patients (12 male, median age 42 years, range 8-71) from three families including visual field (Campus Goldmann), fundus autofluorescence (FAF), optical coherence tomography (OCT) and electrophysiology. Phenotypes were classified into four categories: CSNB (N = 3, 20%) sector RP (N = 3, 20%), pericentral RP (N = 1, 6.7%) and classic RP (N = 8, 53.3% (8/15)). The phenotypes were not associated with family, sex or age (Kruskal-Wallis, p > 0.05), however, cystoid macular edema (CME) was observed only in one family. Among the subjects reporting nyctalopia, 69% (22/32) were male. The clinical characteristics of the largest p.G90D cohort so far showed a large frequency of progressive retinal degeneration with 53.3% developing RP, contrary to the previous report.
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Affiliation(s)
- Nina Kobal
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia; (N.K.); (T.K.); (M.Š.); (M.H.)
| | - Tjaša Krašovec
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia; (N.K.); (T.K.); (M.Š.); (M.H.)
| | - Maja Šuštar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia; (N.K.); (T.K.); (M.Š.); (M.H.)
| | - Marija Volk
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (B.P.)
| | - Borut Peterlin
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (B.P.)
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia; (N.K.); (T.K.); (M.Š.); (M.H.)
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva ulica 46, 1000 Ljubljana, Slovenia; (N.K.); (T.K.); (M.Š.); (M.H.)
- Correspondence:
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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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Allon G, Friedrich Y, Mezer E, Itzhaki A, Leibu R, Perlman I. Verifying complaints of difficulties in night vision using electroretinography and dark adaptation tests. Doc Ophthalmol 2019; 140:169-180. [PMID: 31621038 DOI: 10.1007/s10633-019-09729-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Accepted: 10/04/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE To determine the electroretinographical and psychophysical parameters that can help to verify patients' complaints of reduced night vision. METHODS We tested 275 consecutive patients with normal appearing fundi, complaining of visual difficulties at night, using flash electroretinography (ERG) and dark adaptation (DA) test. Two ERG parameters were used to assess a scotopic retinal function: the amplitude of the response to dim blue flash (the rod response) and the b-wave ratio (measured/expected). Dark adaptation was measured with green- and red-light stimuli after exposure to a bright, bleaching light. The psychophysical parameter of night vision was defined as the threshold for detection of the blue-green stimulus that was measured after 40-45 min in complete darkness. RESULTS Fifty-five patients were excluded from the analysis because of a discrepancy between the two ERG parameters in assessment of scotopic retinal function. The remaining 220 patients were divided into 4 groups: (1) normal ERG and normal DA, (2) subnormal ERG and subnormal DA, (3) normal ERG and subnormal DA and (4) subnormal ERG and normal DA. The ERG and DA tests supported the complaint of visual difficulties at night in 67 patients (group 2), while 34 patients were characterized as having normal scotopic visual function (group 1). The other 119 patients (groups 3 and 4) presented a diagnostic dilemma because one test (ERG or dark adaptation) showed normal scotopic function, while the other indicated subnormal scotopic function. CONCLUSION Our findings indicate that ERG is an essential, but not sufficient test for verifying patient's complaint on visual difficulties in the dark. We suggest using both electroretinography and psychophysical dark adaptation to test patients complaining of reduced night vision.
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Affiliation(s)
- Gilad Allon
- Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel
| | | | - Eedy Mezer
- Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.,Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel
| | - Aviran Itzhaki
- Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Rina Leibu
- Department of Ophthalmology, Rambam Health Care Campus, Haifa, Israel
| | - Ido Perlman
- Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
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Hayashi T, Hosono K, Kurata K, Katagiri S, Mizobuchi K, Ueno S, Kondo M, Nakano T, Hotta Y. Coexistence of GNAT1 and ABCA4 variants associated with Nougaret-type congenital stationary night blindness and childhood-onset cone-rod dystrophy. Doc Ophthalmol 2019; 140:147-157. [PMID: 31583501 DOI: 10.1007/s10633-019-09727-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Accepted: 09/24/2019] [Indexed: 10/25/2022]
Abstract
PURPOSE A single variant (p.G38D) in the GNAT1 gene, encoding the rod-specific transducin α-subunit in phototransduction, has been reported only in one French family with Nougaret-type autosomal dominant congenital stationary night blindness (CSNB). We identified a Japanese family with Nougaret-type CSNB and cone-rod dystrophy (CORD). METHODS Five patients with CSNB and two patients with childhood-onset CORD were recruited. We performed a comprehensive ophthalmic examination including electroretinography (ERG). Disease-causing variants were identified by whole exome sequencing, with candidates confirmed by Sanger sequencing in nine family members. RESULTS The GNAT1 variant (p.G38D) was identified in all four CSNB patients, whereas the two CORD patients carried biallelic truncated known ABCA4 variants as well as the GNAT1 variant. Clinically, no remarkable findings were observed in fuduscopy, fundus autofluorescence, or optical coherence tomography images from the CSNB patients. No response was detectable by rod ERG. The a-waves of standard and bright flash ERG were delayed and broadened rather than biphasic, and b/a-wave amplitude ratio was negative. Cone and 30-Hz flicker responses were normal, and overall, the ERG findings were compatible with previous descriptions of Nougaret-type CSNB. ERG of the CORD patients with macular atrophy showed non-recordable rod response and severely decreased standard flash, cone and 30-Hz flicker responses. CONCLUSIONS This is the second report of a Nougaret-type CSNB family with the GNAT1 variant. Our novel findings suggest that coexistence of the GNAT1 and biallelic ABCA4 variants is associated with an overlapping phenotype with both Nougaret-type CSNB and CORD.
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Affiliation(s)
- Takaaki Hayashi
- Department of Ophthalmology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan. .,Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, 6-41-2 Aoto, Katsushika-ku, Tokyo, 125-8506, Japan.
| | - Katsuhiro Hosono
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Kentaro Kurata
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Satoshi Katagiri
- Department of Ophthalmology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Kei Mizobuchi
- Department of Ophthalmology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Shinji Ueno
- Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Aichi, Japan
| | - Mineo Kondo
- Department of Ophthalmology, Mie University Graduate School of Medicine, Tsu, Mie, Japan
| | - Tadashi Nakano
- Department of Ophthalmology, The Jikei University School of Medicine, Minato-ku, Tokyo, Japan
| | - Yoshihiro Hotta
- Department of Ophthalmology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
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