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Parameswarappa DC, Bagga DK, Upadhyaya A, Balasubramanian J, Pochaboina V, Muthineni V, Jalali S, Kannabiran C. RPE65 mutations in Leber congenital amaurosis, early-onset severe retinal dystrophy, and retinitis pigmentosa from a tertiary eye care center in India. Ophthalmic Genet 2024:1-10. [PMID: 38323530 DOI: 10.1080/13816810.2024.2309559] [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: 06/22/2023] [Accepted: 01/19/2024] [Indexed: 02/08/2024]
Abstract
INTRODUCTION Mutations in the retinal pigment epithelial 65 kilodalton protein (RPE65) gene are associated with various inherited retinal diseases (IRDs), including Leber congenital amaurosis (LCA), early-onset severe retinal dystrophy (EOSRD), and retinitis pigmentosa (RP). We screened for mutations in RPE65 in a series of Indian patients with these IRDs to determine the frequency/types of mutations and to describe the associated phenotypes. MATERIALS AND METHODS Diagnosis of LCA, EOSRD, and RP was made by standard and pre-defined criteria. Patients were evaluated by clinical, retinal imaging, and electrophysiological parameters. Genomic DNA from patients and available family members were used for identifying mutations by direct Sanger sequencing of the RPE65 gene or targeted NGS gene panel for IRDs covering 260+ genes. Variations detected were tested in healthy control populations and for co-segregation with the disease in available family members. RESULTS Mutations were found in eight patients, out of 220 total cases screened, all homozygous for the respective mutant alleles. Seven patients had mutations leading to premature termination codons and one patient had a missense change. The onset of visual loss ranged from birth to <2 years of life. At presentation, RPE mottling in the background retina was present in all cases with macular involvement in five cases with or without vascular attenuation and optic disc pallor. CONCLUSION RPE65 mutations in this series were found in 3.6% of cases associated with severe, early-onset disease, with consistent RPE mottling and variable manifestations with regard to the extent of disc pallor, arteriolar attenuation, and appearance of the macula.
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Affiliation(s)
- Deepika C Parameswarappa
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Anant Bajaj Retina Institute, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
| | - Deepak Kumar Bagga
- Meera and L B Deshpande Centre for Sight Enhancement, Institute for Vision Rehabilitation, L V Prasad Eye Institute, Hyderabad, India
| | - Abhishek Upadhyaya
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Anant Bajaj Retina Institute, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
| | | | - Venkatesh Pochaboina
- Department of Clinical Genetics and Genetic Counseling, L V Prasad Eye Institute, Hyderabad, India
| | - Vani Muthineni
- Kallam Anji Reddy Molecular Genetics Laboratory, L V Prasad Eye Institute, Hyderabad, India
| | - Subhadra Jalali
- Srimati Kanuri Santhamma Center for Vitreoretinal Diseases, Anant Bajaj Retina Institute, Kallam Anji Reddy Campus, L V Prasad Eye Institute, Hyderabad, India
| | - Chitra Kannabiran
- Kallam Anji Reddy Molecular Genetics Laboratory, L V Prasad Eye Institute, Hyderabad, India
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Stepanova A, Ogorodova N, Kadyshev V, Shchagina O, Kutsev S, Polyakov A. A Molecular Genetic Analysis of RPE65-Associated Forms of Inherited Retinal Degenerations in the Russian Federation. Genes (Basel) 2023; 14:2056. [PMID: 38002999 PMCID: PMC10671290 DOI: 10.3390/genes14112056] [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: 09/13/2023] [Revised: 10/26/2023] [Accepted: 11/01/2023] [Indexed: 11/26/2023] Open
Abstract
Pathogenic variants in the RPE65 gene cause the only known form of inherited retinal degenerations (IRDs) that are prone to gene therapy. The current study is aimed at the evaluation of the prevalence of RPE65-associated retinopathy in the Russian Federation, the characterization of known variants in the RPE65 gene, and the establishment of the specificities of the mutation spectrum in Russian patients. METHODS The analysis was carried out on blood samples obtained from 1053 non-related IRDs patients. The analysis, which consisted of 211 genes, was carried out based on the method of massive parallel sequencing (MPS) for all probands. Variant validation, as well as biallelic status verification, were carried out using direct automated Sanger sequencing. The number of copies of RPE65 exons 1-14 was analyzed with quantitative MLPA using an MRC-Holland SALSA MLPA probemix. RESULTS Out of 1053 non-related patients, a molecular genetic diagnosis of IRDs has been confirmed in 474 cases, including 25 (5.3%) patients with RPE65-associated retinopathy. We detected 26 variants in the RPE65 gene, nine of which have not been previously described in the literature. The most common mutations in the Russian population were c.304G>T/p.(Glu102*), c.370C>T/p.(Arg124*), and c.272G>A/p.(Arg91Gln), which comprised 41.8% of all affected chromosomes. CONCLUSIONS The current study shows that pathogenic variants in the RPE65 gene contribute significantly to the pathogenesis of IRDs and comprise 5.3% of all patients with a confirmed molecular genetic diagnosis. This study allowed for the formation of a cohort for target therapy of the disorder; such therapy has already been carried out for some patients.
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Affiliation(s)
- Anna Stepanova
- Research Centre for Medical Genetics, Moscow 115478, Russia
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Wu J, Sun Z, Zhang DW, Liu HL, Li T, Zhang S, Wu J. Development of a novel prediction model based on protein structure for identifying RPE65-associated inherited retinal disease (IRDs) of missense variants. PeerJ 2023; 11:e15702. [PMID: 37547722 PMCID: PMC10404030 DOI: 10.7717/peerj.15702] [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: 11/25/2022] [Accepted: 06/14/2023] [Indexed: 08/08/2023] Open
Abstract
Purpose This study aimed to develop a prediction model to classify RPE65-mediated inherited retinal disease (IRDs) based on protein secondary structure and to analyze phenotype-protein structure correlations of RPE65 missense variants in a Chinese cohort. Methods Pathogenic or likely pathogenic missense variants of RPE65 were obtained from UniProt, ClinVar, and HGMD databases. The three-dimensional structure of RPE65 was retrieved from the Protein Data Bank (PDB) and modified with Pymol software. A novel prediction model was developed using LASSO regression and multivariate logistic regression to identify RPE65-associated IRDs. A total of 21 Chinese probands with RPE65 variants were collected to analyze phenotype-protein structure correlations of RPE65 missense variants. Results The study found that both pathogenic and population missense variants were associated with structural features of RPE65. Pathogenic variants were linked to sheet, β-sheet, strands, β-hairpins, Fe2+ (iron center), and active site cavity, while population variants were related to helix, loop, helices, and helix-helix interactions. The novel prediction model showed accuracy and confidence in predicting the disease type of RPE65 variants (AUC = 0.7531). The study identified 25 missense variants in Chinese patients, accounting for 72.4% of total mutations. A significant correlation was observed between clinical characteristics of RPE65-associated IRDs and changes in amino acid type, specifically for missense variants of F8 (H68Y, P419S). Conclusion The study developed a novel prediction model based on the protein structure of RPE65 and investigated phenotype-protein structure correlations of RPE65 missense variants in a Chinese cohort. The findings provide insights into the precise diagnosis of RPE65-mutated IRDs.
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Affiliation(s)
- Jiawen Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Zhongmou Sun
- University of Rochester School of Medicine and Dentistry, New York, United States of America
| | - Dao wei Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Hong-Li Liu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Ting Li
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
| | - Shenghai Zhang
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health, Shanghai, China
| | - Jihong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China
- State Key Laboratory of Medical Neurobiology, Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Shanghai, China
- Key Laboratory of Myopia, Ministry of Health, Shanghai, China
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Cho EH, Park JE, Lee T, Ha K, Ki CS. Carrier frequency and incidence estimation of RPE65-associated inherited retinal diseases in East Asian population by population database-based analysis. Orphanet J Rare Dis 2022; 17:409. [PMID: 36352427 PMCID: PMC9644481 DOI: 10.1186/s13023-022-02566-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/07/2022] [Accepted: 10/30/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Inherited retinal diseases (IRDs) are clinically and genetically heterogenous disorders leading to visual impairment and blindness. Because gene therapy for RPE65-associated IRDs was recently approved, it is necessary to predict the carrier frequency and prevalence for RPE65-associated IRDs. This study aimed to analyze the carrier frequency and expected incidence of RPE65-associated IRDs in East Asians and Koreans using exome data from the Genome Aggregation Database (gnomAD) and the Korean Reference Genome Database (KRGDB). METHODS We analyzed 9,197 exomes for East Asian populations from gnomAD comprising 1,909 Korean and 1,722 Korean genomes from KRGDB. All identified RPE65 variants were classified according to the 2015 American College of Medical Genetics and Genomics and the Association for Molecular Pathology guidelines. RESULTS The total carrier frequencies of East Asians and Koreans from both gnomAD and KRGDB were 0.10% (11/10,919) and 0.06% (2/3,631), respectively. The estimated incidence of RPE65-associated IRDs was 1/3,941,308 in East Asians and 1/13,184,161 in Koreans. CONCLUSION This study identified carrier frequencies of RPE65-associated IRDs in East Asians and Koreans using gnomAD and KRGDB. We confirmed that the carrier frequency of RPE65-associated IRDs patients was low in Koreans among all East Asian populations, and the incidence was also predicted to be lower than in other East Asian populations. The variant spectrum of RPE65 gene in East Asian and Korean populations differed greatly from those of other ethnic groups.
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Affiliation(s)
- Eun Hye Cho
- grid.264381.a0000 0001 2181 989XDepartment of Laboratory Medicine, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jong Eun Park
- grid.412145.70000 0004 0647 3212Department of Laboratory Medicine, Hanyang University Guri Hospital, Hanyang University College of Medicine, Hanyang University Guri Hospital, 153, Gyeongchun-ro, 11923 Guri-si, Gyeonggi-do Republic of Korea
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Kwak JJ, Kim HR, Byeon SH. Short-Term Outcomes of the First in Vivo Gene Therapy for RPE65-Mediated Retinitis Pigmentosa. Yonsei Med J 2022; 63:701-705. [PMID: 35748082 PMCID: PMC9226827 DOI: 10.3349/ymj.2022.63.7.701] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/29/2022] [Accepted: 03/30/2022] [Indexed: 11/29/2022] Open
Abstract
Here, we report early treatment outcomes of gene therapy for early onset retinitis pigmentosa (RP) (Leber congenital amaurosis) associated with biallelic RPE65 mutation in a 30-year-old female patient. Initially, her visual acuity (VA) was 20/200, and her visual field (VF) was severely constricted to the center in the left eye. Her electroretinography showed nearly extinct signals. Full-field stimulus threshold test (FST) revealed diminished dark-adapted light sensitivity. Voretigene neparvovec-rzyl (VN) is the first in vivo viral gene therapy agent to be approved. At 3 months after subretinal injection of VN in the left eye, VA, VF, and FST showed sustained improvement. She did not exhibit any signs of adverse effects from the treatment. Gene therapy for RP proved to be an effective and safe treatment in an advanced case of RPE65-associatied early onset RP.
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Affiliation(s)
- Jay Jiyong Kwak
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea
| | - Hae Rang Kim
- Department of Ophthalmology, CHA Bundang Medical Center, CHA University School of Medicine, Seongnam, Korea
| | - Suk Ho Byeon
- Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, Korea.
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Bhardwaj A, Yadav A, Yadav M, Tanwar M. Genetic dissection of non-syndromic retinitis pigmentosa. Indian J Ophthalmol 2022; 70:2355-2385. [PMID: 35791117 PMCID: PMC9426071 DOI: 10.4103/ijo.ijo_46_22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Retinitis pigmentosa (RP) belongs to a group of pigmentary retinopathies. It is the most common form of inherited retinal dystrophy, characterized by progressive degradation of photoreceptors that leads to nyctalopia, and ultimately, complete vision loss. RP is distinguished by the continuous retinal degeneration that progresses from the mid-periphery to the central and peripheral retina. RP was first described and named by Franciscus Cornelius Donders in the year 1857. It is one of the leading causes of bilateral blindness in adults, with an incidence of 1 in 3000 people worldwide. In this review, we are going to focus on the genetic heterogeneity of this disease, which is provided by various inheritance patterns, numerosity of variations and inter-/intra-familial variations based upon penetrance and expressivity. Although over 90 genes have been identified in RP patients, the genetic cause of approximately 50% of RP cases remains unknown. Heterogeneity of RP makes it an extremely complicated ocular impairment. It is so complicated that it is known as “fever of unknown origin”. For prognosis and proper management of the disease, it is necessary to understand its genetic heterogeneity so that each phenotype related to the various genetic variations could be treated.
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Affiliation(s)
- Aarti Bhardwaj
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Anshu Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Manoj Yadav
- Department of Genetics, M. D. University, Rohtak, Haryana, India
| | - Mukesh Tanwar
- Department of Genetics, M. D. University, Rohtak, Haryana, India
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Multi- and Transgenerational Effects of Developmental Exposure to Environmental Levels of PFAS and PFAS Mixture in Zebrafish ( Danio rerio). TOXICS 2022; 10:toxics10060334. [PMID: 35736942 PMCID: PMC9228135 DOI: 10.3390/toxics10060334] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 06/10/2022] [Accepted: 06/17/2022] [Indexed: 02/01/2023]
Abstract
Per- and polyfluoroalkyl substances (PFASs) are ubiquitous in the environment and are tied to myriad health effects. Despite the phasing out of the manufacturing of two types of PFASs (perfluorosulfonic acid (PFOS) and perfluorooctanoic acid (PFOA)), chemical composition renders them effectively indestructible by ambient environmental processes, where they thus remain in water. Exposure via water can affect both human and aquatic wildlife. PFASs easily cross the placenta, exposing the fetus at critical windows of development. Little is known about the effects of low-level exposure during this period; even less is known about the potential for multi- and transgenerational effects. We examined the effects of ultra-low, very low, and low-level PFAS exposure (7, 70, and 700 ng/L PFOA; 24, 240, 2400 ng/L PFOS; and stepwise mixtures) from 0–5 days post-fertilization (dpf) on larval zebrafish (Danio rerio) mortality, morphology, behavior and gene expression and fecundity in adult F0 and F1 fish. As expected, environmentally relevant PFAS levels did not affect survival. Morphological abnormalities were not observed until the F1 and F2 generations. Behavior was affected differentially by each chemical and generation. Gene expression was increasingly perturbed in each generation but consistently showed lipid pathway disruption across all generations. Dysregulation of behavior and gene expression is heritable, even in larvae with no direct or indirect exposure. This is the first report of the transgenerational effects of PFOA, PFOS, and their mixture in terms of zebrafish behavior and untargeted gene expression.
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Testa F, Murro V, Signorini S, Colombo L, Iarossi G, Parmeggiani F, Falsini B, Salvetti AP, Brunetti-Pierri R, Aprile G, Bertone C, Suppiej A, Romano F, Karali M, Donati S, Melillo P, Sodi A, Quaranta L, Rossetti L, Buzzonetti L, Chizzolini M, Rizzo S, Staurenghi G, Banfi S, Azzolini C, Simonelli F. RPE65-Associated Retinopathies in the Italian Population: A Longitudinal Natural History Study. Invest Ophthalmol Vis Sci 2022; 63:13. [PMID: 35129589 PMCID: PMC8822366 DOI: 10.1167/iovs.63.2.13] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose To investigate the course of inherited retinal degenerations (IRD) due to mutations in the RPE65 gene. Methods This longitudinal multicentric retrospective chart-review study was designed to collect best corrected visual acuity (BCVA), Goldman visual field, optical coherence tomography (OCT), and electroretinography (ERG) measurements. The data, including imaging, were collected using an electronic clinical research form and were reviewed at a single center to improve consistency. Results From an overall cohort of 60 Italian patients with RPE65-associated IRD, 43 patients (mean age, 27.8 ± 19.7 years) were included and showed a mean BCVA of 2.0 ± 1.0 logMAR. Time-to-event analysis revealed a median age of 33.8 years and 41.4 years to reach low vision and blindness based on BCVA, respectively. ERG (available for 34 patients) showed undetectable responses in most patients (26; 76.5%). OCT (available for 31 patients) revealed epiretinal membranes in five patients (16.1%). Central foveal thickness significantly decreased with age at a mean annual rate of −0.6%/y (P = 0.044). We identified 43 different variants in the RPE65 gene in the entire cohort. Nine variants were novel. Finally, to assess genotype-phenotype correlations, patients were stratified according to the number of RPE65 loss-of-function (LoF) alleles. Patients without LoF variants showed significantly (P < 0.05) better BCVA compared to patients with one or two LoF alleles. Conclusions We described the natural course of RPE65-associated IRD in an Italian cohort showing for the first time a specific genotype-phenotype association. Our findings can contribute to a better management of RPE65-associated IRD patients.
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Affiliation(s)
- Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Vittoria Murro
- Eye Clinic, Neuromuscolar and Sense Organs Department, Careggi University Hospital, Florence, Italy
| | - Sabrina Signorini
- Developmental Neuro-ophthalmology Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - Leonardo Colombo
- Eye Clinic, ASST Santi Paolo e Carlo Hospital, University of Milan, Milan, Italy
| | - Giancarlo Iarossi
- Department of Ophthalmology, Bambino Gesù IRCCS Children's Hospital, Rome, Italy
| | - Francesco Parmeggiani
- Department of Translational Medicine and for Romagna, University of Ferrara, Ferrara, Italy.,ERN-EYE Network-Center for Retinitis Pigmentosa of Veneto Region, Camposampiero Hospital, Padova, Italy
| | - Benedetto Falsini
- Institute of Ophthalmology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Anna Paola Salvetti
- Eye Clinic, Department of Biomedical and Clinical Science, Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Raffaella Brunetti-Pierri
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Giorgia Aprile
- Developmental Neuro-ophthalmology Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - Chiara Bertone
- Department of Surgical and Clinical, Diagnostic and Pediatric Sciences, Section of Ophthalmology, University of Pavia, IRCCS Fondazione Policlinico San Matteo, Pavia, Italy
| | - Agnese Suppiej
- Department of Medical Sciences, University of Ferrara, Ferrara, Italy
| | - Francesco Romano
- Eye Clinic, Department of Biomedical and Clinical Science, Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Marianthi Karali
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy.,Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Simone Donati
- Unit of Ophthalmology, Azienda Socio-Sanitaria Territoriale (ASST) Dei Sette Laghi, Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Paolo Melillo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Andrea Sodi
- Eye Clinic, Neuromuscolar and Sense Organs Department, Careggi University Hospital, Florence, Italy
| | - Luciano Quaranta
- Department of Surgical and Clinical, Diagnostic and Pediatric Sciences, Section of Ophthalmology, University of Pavia, IRCCS Fondazione Policlinico San Matteo, Pavia, Italy
| | - Luca Rossetti
- Eye Clinic, ASST Santi Paolo e Carlo Hospital, University of Milan, Milan, Italy
| | - Luca Buzzonetti
- Department of Ophthalmology, Bambino Gesù IRCCS Children's Hospital, Rome, Italy
| | - Marzio Chizzolini
- ERN-EYE Network-Center for Retinitis Pigmentosa of Veneto Region, Camposampiero Hospital, Padova, Italy
| | - Stanislao Rizzo
- Institute of Ophthalmology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Giovanni Staurenghi
- Eye Clinic, Department of Biomedical and Clinical Science, Luigi Sacco Hospital, University of Milan, Milan, Italy
| | - Sandro Banfi
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Medical Genetics, Department of Precision Medicine, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Claudio Azzolini
- Unit of Ophthalmology, Azienda Socio-Sanitaria Territoriale (ASST) Dei Sette Laghi, Department of Medicine and Surgery, University of Insubria, Varese, Italy
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, University of Campania Luigi Vanvitelli, Naples, Italy
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Kiser PD. Retinal pigment epithelium 65 kDa protein (RPE65): An update. Prog Retin Eye Res 2021; 88:101013. [PMID: 34607013 PMCID: PMC8975950 DOI: 10.1016/j.preteyeres.2021.101013] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 12/21/2022]
Abstract
Vertebrate vision critically depends on an 11-cis-retinoid renewal system known as the visual cycle. At the heart of this metabolic pathway is an enzyme known as retinal pigment epithelium 65 kDa protein (RPE65), which catalyzes an unusual, possibly biochemically unique, reaction consisting of a coupled all-trans-retinyl ester hydrolysis and alkene geometric isomerization to produce 11-cis-retinol. Early work on this isomerohydrolase demonstrated its membership to the carotenoid cleavage dioxygenase superfamily and its essentiality for 11-cis-retinal production in the vertebrate retina. Three independent studies published in 2005 established RPE65 as the actual isomerohydrolase instead of a retinoid-binding protein as previously believed. Since the last devoted review of RPE65 enzymology appeared in this journal, major advances have been made in a number of areas including our understanding of the mechanistic details of RPE65 isomerohydrolase activity, its phylogenetic origins, the relationship of its membrane binding affinity to its catalytic activity, its role in visual chromophore production for rods and cones, its modulation by macromolecules and small molecules, and the involvement of RPE65 mutations in the development of retinal diseases. In this article, I will review these areas of progress with the goal of integrating results from the varied experimental approaches to provide a comprehensive picture of RPE65 biochemistry. Key outstanding questions that may prove to be fruitful future research pursuits will also be highlighted.
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Affiliation(s)
- Philip D Kiser
- Research Service, VA Long Beach Healthcare System, Long Beach, CA, 90822, USA; Department of Physiology & Biophysics, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA; Department of Ophthalmology and Center for Translational Vision Research, Gavin Herbert Eye Institute, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA.
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