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Sen P, Srikrupa N, Maitra P, Srilekha S, Porkodi P, Gnanasekaran H, Bhende M, Khetan V, Mathavan S, Bhende P, Ratra D, Raman R, Rao C, Sripriya S. Next-generation sequencing--based genetic testing and phenotype correlation in retinitis pigmentosa patients from India. Indian J Ophthalmol 2023; 71:2512-2520. [PMID: 37322672 PMCID: PMC10417947 DOI: 10.4103/ijo.ijo_2579_22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 03/14/2023] [Accepted: 03/19/2023] [Indexed: 06/17/2023] Open
Abstract
Purpose Inherited retinal dystrophies (IRD) are a heterogeneous group of retinal diseases leading to progressive loss of photoreceptors through apoptosis. Retinitis pigmentosa (RP) is considered the most common form of IRD. Panel-based testing in RP has proven effective in identifying the causative genetic mutations in 70% and 80% of the patients. This is a retrospective, observational, single-center study of 107 RP patients who had undergone next-generation sequencing-based targeted gene panel testing for IRD genes. These patients were inspected for common phenotypic features to arrive at meaningful genotype-phenotype correlation. Methods Patients underwent complete ophthalmic examination, and blood was collected from the proband for DNA extraction after documenting the pedigree. Targeted Next Generation Sequencing (NGS) was done by panel-based testing for IRD genes followed by co-segregation analysis wherever applicable. Results Of the 107 patients, 72 patients had pathogenic mutations. The mean age of onset of symptoms was 14 ± 12 years (range: 5-55). Mean (Best Corrected Visual Acuity) BCVA was 6/48 (0.9 logMAR) (range 0.0-3.0). At presentation, over one-third of eyes had BCVA worse than 6/60 (<1 logMAR). Phenotype analysis with the gene defects showed overlapping features, such as peripheral well-defined chorioretinal atrophic patches in patients with CERKL, PROM1, and RPE65 gene mutations and large macular lesions in patients with RDH12 and CRX gene mutations, respectively. Nummular or clump-like pigmentation was noted in CRB1, TTC8, PDE6A, and PDE6B. Conclusion NGS-based genetic testing can help clinicians to diagnose RP more accurately, and phenotypic correlations can also help in better patient counselling with respect to prognosis and guidance regarding ongoing newer gene-based therapies.
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Affiliation(s)
- Parveen Sen
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Natarajan Srikrupa
- SNONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Puja Maitra
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Sundaramurthy Srilekha
- SNONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Periyasamy Porkodi
- SNONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Harshavardhini Gnanasekaran
- SNONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Muna Bhende
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Vikas Khetan
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Sinnakaruppan Mathavan
- SNONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Pramod Bhende
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Dhanashree Ratra
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Rajiv Raman
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Chetan Rao
- Shri Bhagwan Mahavir Vitreoretinal Services, Medical Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
| | - Sarangapani Sripriya
- SNONGC Department of Genetics and Molecular Biology, Vision Research Foundation, Sankara Nethralaya, Chennai, Tamil Nadu, India
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Li Y, Li R, Dai H, Li G. Novel variants in PDE6A and PDE6B genes and its phenotypes in patients with retinitis pigmentosa in Chinese families. BMC Ophthalmol 2022; 22:27. [PMID: 35033039 PMCID: PMC8761266 DOI: 10.1186/s12886-021-02242-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 12/30/2021] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND Retinitis pigmentosa (RP) is a genetically heterogeneous disease with 89 causative genes identified to date. However, only approximately 60% of RP cases genetically solved to date, predicating that many novel disease-causing variants are yet to be identified. The purpose of this study is to identify novel variants in PDE6A and PDE6B genes and present its phenotypes in patients with retinitis pigmentosa in Chinese families. METHODS Five retinitis pigmentosa patients with PDE6A variants and three with PDE6B variants were identified through a hereditary eye disease enrichment panel (HEDEP), all patients' medical and ophthalmic histories were collected, and ophthalmological examinations were performed, followed by an analysis of the possible causative variants. Sanger sequencing was used to verify the variants. RESULTS We identified 20 variants in eight patients: 16 of them were identified in either PDE6A or PDE6B in a compound heterozygous state. Additional four heterozygous variants were identified in the genes ADGRA3, CA4, OPTN, RHO. Two novel genetic changes in PDE6A were identified (c.1246G > A and c.1747 T > A), three novel genetic changes in PDE6B were identified (c.401 T > C, c.2293G > C and c.1610-1612del), out of the novel identified variants one was most probably non-pathogenic (c.2293G > C), all other novel variants are pathogenic. Additional variant was identified in CA4 and RHO, which can cause ADRP (c.243G > A, c.688G > A). In addition, a novel variant in ADGRA3 was identified (c.921-1G > A). CONCLUSIONS This study reveals novel and known variants in PDE6A and PDE6B genes in Chinese families with autosomal recessive RP, and expands the clinical and genetic findings of photoreceptor-specific enzyme deficiencies.
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Affiliation(s)
- Yuyu Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
| | - Ruyi Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
| | - Hehua Dai
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
| | - Genlin Li
- Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthalmology & Visual Sciences Key Lab, Beijing, 100730 People’s Republic of China
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3
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Clinical Phenotype of PDE6B-Associated Retinitis Pigmentosa. Int J Mol Sci 2021; 22:ijms22052374. [PMID: 33673512 PMCID: PMC7956818 DOI: 10.3390/ijms22052374] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 02/17/2021] [Accepted: 02/21/2021] [Indexed: 11/25/2022] Open
Abstract
In this retrospective, longitudinal, observational cohort study, we investigated the phenotypic and genotypic features of retinitis pigmentosa associated with variants in the PDE6B gene. Patients underwent clinical examination and genetic testing at a single tertiary referral center, including best-corrected visual acuity (BCVA), kinetic visual field (VF), full-field electroretinography, full-field stimulus threshold, spectral domain optical coherence tomography, and fundus autofluorescence imaging. The genetic testing comprised candidate gene sequencing, inherited retinal disease gene panel sequencing, whole-genome sequencing, and testing for familial variants by Sanger sequencing. Twenty-four patients with mutations in PDE6B from 21 families were included in the study (mean age at the first visit: 32.1 ± 13.5 years). The majority of variants were putative splicing defects (8/23) and missense (7/23) mutations. Seventy-nine percent (38/48) of eyes had no visual acuity impairment at the first visit. Visual acuity impairment was mild in 4% (2/48), moderate in 13% (6/48), and severe in 4% (2/48). BCVA was symmetrical in the right and left eyes. The kinetic VF measurements were highly symmetrical in the right and left eyes, as was the horizontal ellipsoid zone (EZ) width. Regarding the genetic findings, 43% of the PDE6B variants found in our patients were novel. Thus, this study contributed substantially to the PDE6B mutation spectrum. The visual acuity impairment was mild in 83% of eyes, providing a window of opportunity for investigational new drugs. The EZ width was reduced in all patients and was highly symmetric between the eyes, making it a promising outcome measure. We expect these findings to have implications on the design of future PDE6B-related retinitis pigmentosa (RP) clinical trials.
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Velez G, Mahajan VB. Molecular Surgery: Proteomics of a Rare Genetic Disease Gives Insight into Common Causes of Blindness. iScience 2020; 23:101667. [PMID: 33134897 PMCID: PMC7586135 DOI: 10.1016/j.isci.2020.101667] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Rare diseases are an emerging global health priority. Although individually rare, the prevalence of rare "orphan" diseases is high, affecting approximately 300 million people worldwide. Treatments for these conditions are often inadequate, leaving the disease to progress unabated. Here, we review the clinical features and pathophysiology of neovascular inflammatory vitreoretinopathy (NIV), a rare inflammatory retinal disease caused by mutations in the CAPN5 gene. Although the prevalence of NIV is low (1 in 1,000,000 people), the disease mimics more common causes of blindness (e.g. uveitis, retinitis pigmentosa, proliferative diabetic retinopathy, and proliferative vitreoretinopathy) at distinct clinical stages. There is no cure for NIV to date. We highlight how personalized proteomics helped identify potential stage-specific biomarkers and drug targets in liquid vitreous biopsies. The NIV vitreous proteome revealed enrichment of molecular pathways associated with common retinal pathologies and implicated superior targets for therapeutic drug repositioning. In addition, we review our pipeline for collecting, storing, and analyzing ophthalmic surgical samples. This approach can be adapted to treat a variety of rare genetic diseases.
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Affiliation(s)
- Gabriel Velez
- Omics Laboratory, Stanford University, Palo Alto, CA, USA
- Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA 94304, USA
- Medical Scientist Training Program, University of Iowa, Iowa City, IA, USA
| | - Vinit B. Mahajan
- Omics Laboratory, Stanford University, Palo Alto, CA, USA
- Department of Ophthalmology, Byers Eye Institute, Stanford University, Palo Alto, CA 94304, USA
- Veterans Affairs Palo Alto Health Care System, Palo Alto, CA, USA
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Karlen SJ, Miller EB, Burns ME. Microglia Activation and Inflammation During the Death of Mammalian Photoreceptors. Annu Rev Vis Sci 2020; 6:149-169. [PMID: 32936734 PMCID: PMC10135402 DOI: 10.1146/annurev-vision-121219-081730] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Photoreceptors are highly specialized sensory neurons with unique metabolic and physiological requirements. These requirements are partially met by Müller glia and cells of the retinal pigment epithelium (RPE), which provide essential metabolites, phagocytose waste, and control the composition of the surrounding microenvironment. A third vital supporting cell type, the retinal microglia, can provide photoreceptors with neurotrophic support or exacerbate neuroinflammation and hasten neuronal cell death. Understanding the physiological requirements for photoreceptor homeostasis and the factors that drive microglia to best promote photoreceptor survival has important implications for the treatment and prevention of blinding degenerative diseases like retinitis pigmentosa and age-related macular degeneration.
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Affiliation(s)
- Sarah J. Karlen
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, California 95616, USA
| | - Eric B. Miller
- Center for Neuroscience, University of California, Davis, Davis, California 95616, USA
| | - Marie E. Burns
- Department of Cell Biology and Human Anatomy, University of California, Davis, Davis, California 95616, USA
- Center for Neuroscience, University of California, Davis, Davis, California 95616, USA
- Department of Ophthalmology & Vision Science, University of California, Davis, Davis, California 95616, USA
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Garafalo AV, Cideciyan AV, Héon E, Sheplock R, Pearson A, WeiYang Yu C, Sumaroka A, Aguirre GD, Jacobson SG. Progress in treating inherited retinal diseases: Early subretinal gene therapy clinical trials and candidates for future initiatives. Prog Retin Eye Res 2020; 77:100827. [PMID: 31899291 PMCID: PMC8714059 DOI: 10.1016/j.preteyeres.2019.100827] [Citation(s) in RCA: 109] [Impact Index Per Article: 27.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2019] [Revised: 12/21/2019] [Accepted: 12/26/2019] [Indexed: 12/15/2022]
Abstract
Due to improved phenotyping and genetic characterization, the field of 'incurable' and 'blinding' inherited retinal diseases (IRDs) has moved substantially forward. Decades of ascertainment of IRD patient data from Philadelphia and Toronto centers illustrate the progress from Mendelian genetic types to molecular diagnoses. Molecular genetics have been used not only to clarify diagnoses and to direct counseling but also to enable the first clinical trials of gene-based treatment in these diseases. An overview of the recent reports of gene augmentation clinical trials by subretinal injections is used to reflect on the reasons why there has been limited success in this early venture into therapy. These first-in human experiences have taught that there is a need for advancing the techniques of delivery of the gene products - not only for refining further subretinal trials, but also for evaluating intravitreal delivery. Candidate IRDs for intravitreal gene delivery are then suggested to illustrate some of the disorders that may be amenable to improvement of remaining central vision with the least photoreceptor trauma. A more detailed understanding of the human IRDs to be considered for therapy and the calculated potential for efficacy should be among the routine prerequisites for initiating a clinical trial.
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Affiliation(s)
- Alexandra V Garafalo
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Rebecca Sheplock
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Alexander Pearson
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Caberry WeiYang Yu
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Alexander Sumaroka
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Gustavo D Aguirre
- Division of Experimental Retinal Therapies, Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA.
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Zhang E, Ryu J, Levi SR, Oh JK, Hsu CW, Cui X, Lee TT, Wang NK, Lima de Carvalho JR, Tsang SH. PKM2 ablation enhanced retinal function and survival in a preclinical model of retinitis pigmentosa. Mamm Genome 2020; 31:77-85. [PMID: 32342224 DOI: 10.1007/s00335-020-09837-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/08/2020] [Indexed: 12/13/2022]
Abstract
Retinitis pigmentosa (RP) is a neurodegenerative disorder that causes irreversible vision loss in over 1.5 million individuals world-wide. The genetic heterogeneity of RP necessitates a broad therapy that is able to provide treatment in a gene- and mutation- non-specific manner. In this study, we identify the therapeutic benefits of metabolic reprogramming by targeting pyruvate kinase M2 (PKM2) in a Pde6β preclinical model of RP. The genetic contributions of PKM2 inhibition in retinal degeneration were evaluated through histology and electroretinogram (ERG) followed by a statistical analysis using a linear regression model. Notably, PKM2 ablation resulted in thicker retinal layers in Pde6β-mutated mice as compared to the controls, suggesting greater photoreceptor survival. Consistent with these anatomical findings, ERG analyses revealed that the maximum b-wave is on average greater in Pkm2 knockout mice than in mice with intact Pkm2, indicating enhanced photoreceptor function. These rescue phenotypes from Pkm2 ablation in a preclinical model of RP indicate that a metabolome reprogramming may be useful in treating RP.
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Affiliation(s)
- Ethan Zhang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Joseph Ryu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Sarah R Levi
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Jin Kyun Oh
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- State University of New York At Downstate Medical Center, Brooklyn, NY, USA
| | - Chun Wei Hsu
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Xuan Cui
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- The College of Optometry, Tianjin Medical University Eye Hospital, Tianjin Medical University Eye Institute, Tianjin, China
| | - Ting-Ting Lee
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Nan-Kai Wang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Ophthalmology, Chang Gung Memorial Hospital, Linkou Medical Center, Taoyuan, Taiwan
| | - Jose Ronaldo Lima de Carvalho
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
- Department of Ophthalmology, Empresa Brasileira de Servicos Hospitalares (EBSERH) - Hospital das Clinicas de Pernambuco (HCPE), Federal University of Pernambuco (UFPE), Recife, Brazil
- Department of Ophthalmology, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.
- Department of Pathology & Cell Biology, Institute of Human Nutrition, and Columbia Stem Cell Initiative, Columbia University, New York, NY, USA.
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Petersen-Jones SM, Occelli LM, Biel M, Michalakis S. Advancing Gene Therapy for PDE6A Retinitis Pigmentosa. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:103-107. [PMID: 31884596 DOI: 10.1007/978-3-030-27378-1_17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
Mutations in the gene encoding the phosphodiesterase 6 alpha subunit (PDE6A) account for 3-4% of autosomal recessive retinitis pigmentosa (RP), and currently no treatment is available. There are four animal models for PDE6A-RP: a dog with a frameshift truncating mutation (p.Asn616ThrfsTer39) and three mouse models with missense mutations (Val685Met, Asp562Trp, and Asp670Gly) showing a range of phenotype severities. Initial proof-of-concept gene augmentation studies in the Asp670Gly mouse model and dog model used a subretinally delivered adeno-associated virus serotype 8 with a 733 tyrosine capsid mutation delivering species-specific Pde6a cDNAs. These restored some rod-mediated function and preserved retinal structure. Subsequently, a translatable vector (AAV8 with a human rhodopsin promoter and human PDE6A cDNA) was tested in the dog and the Asp670Gly mouse model. In the dog, there was restoration of rod function, a robust rod-mediated ERG, and introduction of dim-light vision. Treatment improved morphology of the photoreceptor layer, and the retina was preserved in the treated region. In the Asp670Gly mouse, therapy also preserved photoreceptors with cone survival being reflected by maintenance of cone-mediated ERG responses. These studies are an important step toward a translatable therapy for PDE6A-RP.
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Affiliation(s)
- Simon M Petersen-Jones
- Department of Small Animal Clinical Sciences, Veterinary Medical Center, Michigan State University, East Lansing, MI, USA.
| | - Laurence M Occelli
- Department of Small Animal Clinical Sciences, Veterinary Medical Center, Michigan State University, East Lansing, MI, USA
| | - Martin Biel
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Stylianos Michalakis
- Center for Integrated Protein Science Munich (CIPSM) at the Department of Pharmacy - Center for Drug Research, Ludwig-Maximilians-Universität München, Munich, Germany
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Metabolite therapy guided by liquid biopsy proteomics delays retinal neurodegeneration. EBioMedicine 2020; 52:102636. [PMID: 32028070 PMCID: PMC7005447 DOI: 10.1016/j.ebiom.2020.102636] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 12/26/2019] [Accepted: 01/09/2020] [Indexed: 02/06/2023] Open
Abstract
Background Neurodegenerative diseases are incurable disorders caused by progressive neuronal cell death. Retinitis pigmentosa (RP) is a blinding neurodegenerative disease that results in photoreceptor death and progresses to the loss of the entire retinal network. We previously found that proteomic analysis of the adjacent vitreous served as way to indirectly biopsy the retina and identify changes in the retinal proteome. Methods We analyzed protein expression in liquid vitreous biopsies from autosomal recessive (ar)RP patients with PDE6A mutations and arRP mice with Pde6ɑ mutations. Proteomic analysis of retina and vitreous samples identified molecular pathways affected at the onset of photoreceptor death. Based on affected molecular pathways, arRP mice were treated with a ketogenic diet or metabolites involved in fatty-acid synthesis, oxidative phosphorylation, and the tricarboxylic acid (TCA) cycle. Findings Dietary supplementation of a single metabolite, ɑ-ketoglutarate, increased docosahexaeonic acid levels, provided neuroprotection, and enhanced visual function in arRP mice. A ketogenic diet delayed photoreceptor cell loss, while vitamin B supplementation had a limited effect. Finally, desorption electrospray ionization mass spectrometry imaging (DESI-MSI) on ɑ-ketoglutarate-treated mice revealed restoration of metabolites that correlated with our proteomic findings: uridine, dihydrouridine, and thymidine (pyrimidine and purine metabolism), glutamine and glutamate (glutamine/glutamate conversion), and succinic and aconitic acid (TCA cycle). Interpretation This study demonstrates that replenishing TCA cycle metabolites via oral supplementation prolongs retinal function and provides a neuroprotective effect on the photoreceptor cells and inner retinal network. Funding NIH grants [R01EY026682, R01EY024665, R01EY025225, R01EY024698, R21AG050437, P30EY026877, 5P30EY019007, R01EY018213, F30EYE027986, T32GM007337, 5P30CA013696], NSF grant CHE-1734082.
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10
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Karali M, Testa F, Brunetti-Pierri R, Di Iorio V, Pizzo M, Melillo P, Barillari MR, Torella A, Musacchia F, D’Angelo L, Banfi S, Simonelli F. Clinical and Genetic Analysis of a European Cohort with Pericentral Retinitis Pigmentosa. Int J Mol Sci 2019; 21:ijms21010086. [PMID: 31877679 PMCID: PMC6982348 DOI: 10.3390/ijms21010086] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Revised: 12/12/2019] [Accepted: 12/19/2019] [Indexed: 12/28/2022] Open
Abstract
Retinitis pigmentosa (RP) is a clinically heterogenous disease that comprises a wide range of phenotypic and genetic subtypes. Pericentral RP is an atypical form of RP characterized by bone-spicule pigmentation and/or atrophy confined in the near mid-periphery of the retina. In contrast to classic RP, the far periphery is better preserved in pericentral RP. The aim of this study was to perform the first detailed clinical and genetic analysis of a cohort of European subjects with pericentral RP to determine the phenotypic features and the genetic bases of the disease. A total of 54 subjects from 48 independent families with pericentral RP, non-syndromic and syndromic, were evaluated through a full ophthalmological examination and underwent clinical exome or retinopathy gene panel sequencing. Disease-causative variants were identified in 22 of the 35 families (63%) in 10 different genes, four of which are also responsible for syndromic RP. Thirteen of the 34 likely pathogenic variants were novel. Intra-familiar variability was also observed. The current study confirms the mild phenotype of pericentral RP and extends the spectrum of genes associated with this condition.
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Affiliation(s)
- Marianthi Karali
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Luigi De Crecchio 7, 80138 Naples, Italy; (M.K.); (A.T.)
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
| | - Francesco Testa
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Raffaella Brunetti-Pierri
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Valentina Di Iorio
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Mariateresa Pizzo
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
| | - Paolo Melillo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Maria Rosaria Barillari
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Annalaura Torella
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Luigi De Crecchio 7, 80138 Naples, Italy; (M.K.); (A.T.)
| | - Francesco Musacchia
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
| | - Luigi D’Angelo
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
| | - Sandro Banfi
- Medical Genetics, Department of Precision Medicine, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Luigi De Crecchio 7, 80138 Naples, Italy; (M.K.); (A.T.)
- Telethon Institute of Genetics and Medicine, via Campi Flegrei 34, 80078 Pozzuoli, Italy; (M.P.); (F.M.)
- Correspondence: (S.B.); (F.S.); Tel.: +39-081-19230628 (S.B.); +39-081-7704501 (F.S.)
| | - Francesca Simonelli
- Eye Clinic, Multidisciplinary Department of Medical, Surgical and Dental Sciences, Università degli Studi della Campania ‘Luigi Vanvitelli’, via Pansini 5, 80131 Naples, Italy; (F.T.); (R.B.-P.); (V.D.I.); (P.M.); (M.R.B.); (L.D.A.)
- Correspondence: (S.B.); (F.S.); Tel.: +39-081-19230628 (S.B.); +39-081-7704501 (F.S.)
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11
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Tatour Y, Tamaiev J, Shamaly S, Colombo R, Bril E, Rabinowitz T, Yaakobi A, Mezer E, Leibu R, Tiosano B, Shomron N, Chowers I, Banin E, Sharon D, Ben-Yosef T. A novel intronic mutation of PDE6B is a major cause of autosomal recessive retinitis pigmentosa among Caucasus Jews. Mol Vis 2019; 25:155-164. [PMID: 30820151 PMCID: PMC6386512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 02/20/2019] [Indexed: 12/02/2022] Open
Abstract
PURPOSE To identify the genetic basis for retinitis pigmentosa (RP) in a cohort of Jewish patients from Caucasia. METHODS Patients underwent a detailed ophthalmic evaluation, including funduscopic examination, visual field testing, optical coherence tomography (OCT), and electrophysiological tests, electroretinography (ERG) and visual evoked potentials (VEP). Genetic analysis was performed with a combination of whole exome sequencing (WES) and Sanger sequencing. Bioinformatic analysis of the WES results was performed via a customized pipeline. Pathogenicity of the identified intronic variant was evaluated in silico using the web tool Human Splicing Finder, and in vitro, using a minigene-based splicing assay. Linkage disequilibrium (LD) analysis was used to demonstrate a founder effect, and the decay of LD over generations around the mutation in Caucasus Jewish chromosomes was modeled to estimate the age of the most recent common ancestor. RESULTS In eight patients with RP from six unrelated families, all of Caucasus Jewish ancestry, we identified a novel homozygous intronic variant, located at position -9 of PDE6B intron 15. The c.1921-9C>G variant was predicted to generate a novel acceptor splice site, nine bases upstream of the original splice site of intron 15. In vitro splicing assay demonstrated that this novel acceptor splice site is used instead of the wild-type site, leading to an 8-bp insertion into exon 16, which is predicted to cause a frameshift. The presence of a common ancestral haplotype in mutation-bearing chromosomes was compatible with a founder effect. CONCLUSIONS The PDE6B c.1921-9C>G intronic mutation is a founder mutation that accounts for at least 40% (6/15 families) of autosomal recessive RP among Caucasus Jews. This result is highly important for molecular diagnosis, carrier screening, and genetic counseling in this population.
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Affiliation(s)
- Yasmin Tatour
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Jonathan Tamaiev
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Shamaly Shamaly
- Department of Ophthalmology, Bnai Zion Medical Center, Haifa, Israel
| | - Roberto Colombo
- Institute of Clinical Biochemistry, Faculty of Medicine, Catholic University of the Sacred Heart, Milan, Italy,Center for the Study of Rare Hereditary Diseases, Niguarda Ca' Granda Metropolitan Hospital, Milan, Italy
| | - Ephrat Bril
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Tom Rabinowitz
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Alona Yaakobi
- Department of Ophthalmology, Hillel Yaffe Medical Center, Hadera, Israel
| | - Eedy Mezer
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel,Alberto Moscona Department of Ophthalmology, Rambam Health Care Center, Haifa, Israel
| | - Rina Leibu
- Alberto Moscona Department of Ophthalmology, Rambam Health Care Center, Haifa, Israel
| | - Beatrice Tiosano
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel,Department of Ophthalmology, Hillel Yaffe Medical Center, Hadera, Israel
| | - Noam Shomron
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Itay Chowers
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Eyal Banin
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Tamar Ben-Yosef
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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12
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Clinical findings of end-stage retinitis pigmentosa with a homozygous PDE6A variant (p.R653X). Am J Ophthalmol Case Rep 2018; 13:110-115. [PMID: 30619975 PMCID: PMC6307093 DOI: 10.1016/j.ajoc.2018.12.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 11/24/2018] [Accepted: 12/17/2018] [Indexed: 12/16/2022] Open
Abstract
Purpose To report clinical and genetic features of a Japanese patient with end-stage retinitis pigmentosa (RP) caused by a homozygous PDE6A variant. Methods We performed comprehensive ophthalmic examinations. Whole exome sequencing analysis was used to investigate the RP patient with parental consanguinity. The pedigree included 4 RP patients in the two generations, which suggests presumed pseudo-autosomal dominant inheritance. Results A PDE6A variant (p.R653X) was identified to be homozygous and disease-causing in the patient. Homozygosity mapping revealed the homozygous region including the variant and confirmation of autosomal recessive inheritance. The patient reported night blindness at 4 years of age and exhibited typical RP fundus appearance with macula involvement during the follow-up period from at the age of 52–69 years. At the age of 52, the patient exhibited a loss of visual acuity and had severely constricted visual fields, with a further gradual deterioration of her vision until she was 69 years old. At the age of 69, funduscopy showed severe chorioretinal degeneration in the area from the posterior pole to the peripheral retina. Conclusions and Importance This is the first report that the PDE6A variant (p.R653X) has been identified as one of the causes of autosomal recessive RP in the Japanese population. Longitudinal natural history/end-stage findings demonstrated early-onset and a severe RP phenotype with macula involvement when the patient was in her 50s and severe chorioretinal degenerations in her late 60s.
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13
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Takahashi VKL, Takiuti JT, Jauregui R, Lima LH, Tsang SH. Structural disease progression in PDE6-associated autosomal recessive retinitis pigmentosa. Ophthalmic Genet 2018; 39:610-614. [PMID: 30153077 DOI: 10.1080/13816810.2018.1509354] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
BACKGROUND AND OBJECTIVE To evaluate the progression of retinitis pigmentosa (RP) caused by mutations in either PDE6A or PDE6B by measuring the progressive constriction of the hyperautofluorescent ring and shortening of the ellipsoid zone (EZ)-line width. PATIENTS AND METHODS Fundus autofluorescence (FAF) and spectral-domain optical coherence tomography (SD-OCT) images were obtained from seven patients with autosomal recessive RP caused by mutations in either PDE6A or PDE6B. Measurements of the EZ line width on SD-OCT images and horizontal, vertical diameter, and ring area on FAF images were performed by two independent graders. The measurements of these four parameters were correlated with one another. RESULTS We observed that the EZ line width decreased by an average of 91 ± 64 µm per year, while the horizontal and vertical diameters decreased by 103 ± 53 µm and 92 ± 49 µm per year, respectively. The ring area decreased by a rate of 0.3 ± 0.18 mm2 per year. Progression rates were similar for the left eye. CONCLUSIONS We observed a progressive loss of EZ line width and Short-wavelength fundus autofluorescence (SW-AF) ring constriction over time. These results may serve as reference for better prognostic prediction and patients selection for clinical trials promoting cone rescue.
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Affiliation(s)
- Vitor K L Takahashi
- a Department of Ophthalmology , Columbia University , New York , New York , USA.,b Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology & Cell Biology, Columbia Stem Cell Initiative, Institute of Human Nutrition, Columbia University , New York , NY , USA.,c Department of Ophthalmology , Federal University of São Paulo , São Paulo , Brazil
| | - Júlia T Takiuti
- a Department of Ophthalmology , Columbia University , New York , New York , USA.,b Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology & Cell Biology, Columbia Stem Cell Initiative, Institute of Human Nutrition, Columbia University , New York , NY , USA.,d Division of Ophthalmology , University of São Paulo Medical School , São Paulo , Brazil
| | - Ruben Jauregui
- a Department of Ophthalmology , Columbia University , New York , New York , USA.,b Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology & Cell Biology, Columbia Stem Cell Initiative, Institute of Human Nutrition, Columbia University , New York , NY , USA.,e Weill Cornell Medical College , New York , NY , USA
| | - Luiz H Lima
- c Department of Ophthalmology , Federal University of São Paulo , São Paulo , Brazil
| | - Stephen H Tsang
- a Department of Ophthalmology , Columbia University , New York , New York , USA.,b Jonas Children's Vision Care and the Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology, Pathology & Cell Biology, Columbia Stem Cell Initiative, Institute of Human Nutrition, Columbia University , New York , NY , USA.,f Department of Pathology & Cell Biology , Stem Cell Initiative (CSCI), Institute of Human Nutrition, College of Physicians and Surgeons, Columbia University , New York , New York , USA
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14
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Zhang S, Li J, Li S, Yang Y, Yang M, Yang Z, Zhu X, Zhang L. Targeted next-generation sequencing reveals that a compound heterozygous mutation in phosphodiesterase 6a gene leads to retinitis pigmentosa in a Chinese family. Ophthalmic Genet 2018; 39:487-491. [PMID: 29693493 DOI: 10.1080/13816810.2018.1461912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Shanshan Zhang
- Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Jie Li
- Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Shujin Li
- Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, China
| | - Yeming Yang
- Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Mu Yang
- Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, China
| | - Zhenglin Yang
- Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
- Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
- Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, China
- Center of Information in Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Xianjun Zhu
- Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
- Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
- Institute of Chengdu Biology, Chinese Academy of Sciences, Chengdu, China
- Center of Information in Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
| | - Lin Zhang
- Key Laboratory for Human Disease Gene Study, Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
- Department of Ophthalmology, Sichuan Academy of Medical Sciences and Sichuan Provincial People’s Hospital, School of Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
- Center of Information in Medicine, University of Electronic Science and Technology of China, Chengdu, Sichuan, China
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15
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Genetic characterization and disease mechanism of retinitis pigmentosa; current scenario. 3 Biotech 2017; 7:251. [PMID: 28721681 DOI: 10.1007/s13205-017-0878-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 07/10/2017] [Indexed: 12/21/2022] Open
Abstract
Retinitis pigmentosa is a group of genetically transmitted disorders affecting 1 in 3000-8000 individual people worldwide ultimately affecting the quality of life. Retinitis pigmentosa is characterized as a heterogeneous genetic disorder which leads by progressive devolution of the retina leading to a progressive visual loss. It can occur in syndromic (with Usher syndrome and Bardet-Biedl syndrome) as well as non-syndromic nature. The mode of inheritance can be X-linked, autosomal dominant or autosomal recessive manner. To date 58 genes have been reported to associate with retinitis pigmentosa most of them are either expressed in photoreceptors or the retinal pigment epithelium. This review focuses on the disease mechanisms and genetics of retinitis pigmentosa. As retinitis pigmentosa is tremendously heterogeneous disorder expressing a multiplicity of mutations; different variations in the same gene might induce different disorders. In recent years, latest technologies including whole-exome sequencing contributing effectively to uncover the hidden genesis of retinitis pigmentosa by reporting new genetic mutations. In future, these advancements will help in better understanding the genotype-phenotype correlations of disease and likely to develop new therapies.
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16
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Agrawal SA, Burgoyne T, Eblimit A, Bellingham J, Parfitt DA, Lane A, Nichols R, Asomugha C, Hayes MJ, Munro PM, Xu M, Wang K, Futter CE, Li Y, Chen R, Cheetham ME. REEP6 deficiency leads to retinal degeneration through disruption of ER homeostasis and protein trafficking. Hum Mol Genet 2017; 26:2667-2677. [PMID: 28475715 PMCID: PMC5808736 DOI: 10.1093/hmg/ddx149] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 04/12/2017] [Accepted: 04/14/2017] [Indexed: 01/09/2023] Open
Abstract
Retinitis pigmentosa (RP) is the most common form of inherited retinal dystrophy. We recently identified mutations in REEP6, which encodes the receptor expression enhancing protein 6, in several families with autosomal recessive RP. REEP6 is related to the REEP and Yop1p family of ER shaping proteins and potential receptor accessory proteins, but the role of REEP6 in the retina is unknown. Here we characterize the disease mechanisms associated with loss of REEP6 function using a Reep6 knockout mouse generated by CRISPR/Cas9 gene editing. In control mice REEP6 was localized to the inner segment and outer plexiform layer of rod photoreceptors. The Reep6-/- mice exhibited progressive photoreceptor degeneration from P20 onwards. Ultrastructural analyses at P20 by transmission electron microscopy and 3View serial block face scanning EM revealed an expansion of the distal ER in the Reep6-/- rods and an increase in their number of mitochondria. Electroretinograms revealed photoreceptor dysfunction preceded degeneration, suggesting potential defects in phototransduction. There was no effect on the traffic of rhodopsin, Rom1 or peripherin/rds; however, the retinal guanylate cyclases GC1 and GC2 were severely affected in the Reep6 knockout animals, with almost undetectable expression. These changes correlated with an increase in C/EBP homologous protein (CHOP) expression and the activation of caspase 12, suggesting that ER stress contributes to cell death. Collectively, these data suggest that REEP6 plays an essential role in maintaining cGMP homeostasis though facilitating the stability and/or trafficking of guanylate cyclases and maintaining ER and mitochondrial homeostasis.
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Affiliation(s)
- Smriti A. Agrawal
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Thomas Burgoyne
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Aiden Eblimit
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - James Bellingham
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - David A. Parfitt
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Amelia Lane
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | | | - Chinwe Asomugha
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Matthew J. Hayes
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Peter M. Munro
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Mingchu Xu
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Keqing Wang
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Clare E. Futter
- UCL Institute of Ophthalmology, 11-43 Bath Street, London EC1V 9EL, UK
| | - Yumei Li
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
| | - Rui Chen
- Department of Molecular and Human Genetics
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX 77030-3411, USA
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17
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Vincent AL, Abeysekera N, van Bysterveldt KA, Oliver VF, Ellingford JM, Barton S, Black GC. Next-generation sequencing targeted disease panel in rod-cone retinal dystrophies in Māori and Polynesian reveals novel changes and a common founder mutation. Clin Exp Ophthalmol 2017; 45:901-910. [PMID: 28488341 DOI: 10.1111/ceo.12983] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 05/02/2017] [Indexed: 01/20/2023]
Abstract
IMPORTANCE This study identifies unique genetic variation observed in a cohort of Māori and Polynesian patients with rod-cone retinal dystrophies using a targeted next-generation sequencing retinal disease gene panel. BACKGROUND With over 250 retinal disease genes identified, genetic diagnosis is still only possible in 60-70% of individuals and even less within unique ethnic groups. DESIGN Prospective genetic testing in patients with rod-cone retinal dystrophies identified from the New Zealand Inherited Retinal Disease Database, PARTICIPANTS: Sixteen patients of Māori and Polynesian ancestry. METHODS Next-generation sequencing of a targeted retinal gene panel. Sanger sequencing for a novel PDE6B mutation in subsequent Māori patients. MAIN OUTCOME MEASURES Genetic diagnosis, genotype-phenotype correlation. RESULTS Thirteen unique pathogenic variants were identified in 9 of 16 (56.25%) patients in 10 different genes. A definitive genetic diagnosis was made in 7/16 patients (43.7%). Six changes were novel and not in public databases of human variation. In four patients, a homozygous, novel pathogenic variant (c.2197G > C, p.(Ala 733Pro)) in PDE6B was identified and also present in a further five similarly affected Māori patients. CONCLUSIONS AND RELEVANCE Over half of the Māori and Polynesian patients with inherited rod-cone diseases have no pathogenic variant(s) detected with a targeted retinal next-generation sequencing strategy, which is supportive of novel genetic mechanisms in this population. A novel PDE6B founder variant is likely to account for 16% of recessive inherited retinal dystrophy in Māori. Careful characterization of the clinical presentation permits identification of further Māori patients with a similar phenotype and simplifies the diagnostic algorithm.
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Affiliation(s)
- Andrea L Vincent
- Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand.,Eye Department, Greenlane Clinical Centre, Auckland District Health Board, Auckland, New Zealand
| | - Nandoun Abeysekera
- Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Katherine A van Bysterveldt
- Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Verity F Oliver
- Department of Ophthalmology, FMHS, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand
| | - Jamie M Ellingford
- Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester, UK
| | - Stephanie Barton
- Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester, UK
| | - Graeme Cm Black
- Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester, UK
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18
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Nair P, Hamzeh AR, Malik EM, Oberoi D, Al-Ali MT, Bastaki F. Novel PDE6A mutation in an Emirati patient with retinitis pigmentosa. Oman J Ophthalmol 2017; 10:228-231. [PMID: 29118501 PMCID: PMC5657168 DOI: 10.4103/ojo.ojo_213_2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Mutations in the PDE6A gene are known to cause a form of retinitis pigmentosa (RP43), characterized by progressive retinal degeneration. We describe an Emirati patient with RP caused by a novel mutation in PDE6A. Clinical diagnosis of RP was made based on clinical evaluation and electroretinograms. The molecular analysis involved performing whole-exome sequencing, which enabled the identification of a homozygous 2-bp deletion (c.1358_1359delAT) in PDE6A, which was predicted to result in a frameshift and premature termination (p.Ile452Serfs*7). The mutation completely removed the catalytic PDEase domain in the protein. The parents were found to be heterozygous carriers of the variant. We thus report the first known case of a pathological variant in the PDE6A gene from the Arabian Peninsula.
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Affiliation(s)
| | | | - Ethar Mustafa Malik
- Department of Pediatric, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | | | | | - Fatma Bastaki
- Department of Pediatric, Latifa Hospital, Dubai Health Authority, Dubai, UAE
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19
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Habibi I, Chebil A, Falfoul Y, Allaman-Pillet N, Kort F, Schorderet DF, El Matri L. Identifying mutations in Tunisian families with retinal dystrophy. Sci Rep 2016; 6:37455. [PMID: 27874104 PMCID: PMC5118704 DOI: 10.1038/srep37455] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/26/2016] [Indexed: 02/08/2023] Open
Abstract
Retinal dystrophies (RD) are a rare genetic disorder with high genetic heterogeneity. This study aimed at identifying disease-causing variants in fifteen consanguineous Tunisian families. Full ophthalmic examination was performed. Index patients were subjected to IROme analysis or whole exome sequencing followed by homozygosity mapping. All detected variations were confirmed by direct Sanger sequencing. Mutation analysis in our patients revealed two compound heterozygous mutations p.(R91W);(V172D) in RPE65, and five novel homozygous mutations: p.R765C in CNGB1, p.H337R in PDE6B, splice site variant c.1129-2A > G and c.678_681delGAAG in FAM161A and c.1133 + 3_1133 + 6delAAGT in CERKL. The latter mutation impacts pre-mRNA splicing of CERKL. The other changes detected were six previously reported mutations in CNGB3 (p.R203*), ABCA4 (p.W782*), NR2E3 (p.R311Q), RPE65 (p.H182Y), PROM1 (c.1354dupT) and EYS (c.5928-2A > G). Segregation analysis in each family showed that all affected individuals were homozygotes and unaffected individuals were either heterozygote carriers or homozygous wild type allele. These results confirm the involvement of a large number of genes in RD in the Tunisian population.
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Affiliation(s)
- Imen Habibi
- Institute for Research in Ophthalmology (IRO), Sion, Switzerland.,Research Laboratory of Oculogenetic (LR14SP01), Department B of Ophthalmology, Hedi Rais Institute of Ophthalmology, Tunis, Tunisia.,Research Laboratory of renal Transplantation and Immunopathology (LR03SP01), University Tunis El Manar, Immunology Laboratory, Tunis, Tunisia.,Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Ahmed Chebil
- Research Laboratory of Oculogenetic (LR14SP01), Department B of Ophthalmology, Hedi Rais Institute of Ophthalmology, Tunis, Tunisia.,Faculty of medicine, University Tunis El Manar, Tunisia
| | - Yosra Falfoul
- Research Laboratory of Oculogenetic (LR14SP01), Department B of Ophthalmology, Hedi Rais Institute of Ophthalmology, Tunis, Tunisia.,Faculty of medicine, University Tunis El Manar, Tunisia
| | | | - Fedra Kort
- Research Laboratory of Oculogenetic (LR14SP01), Department B of Ophthalmology, Hedi Rais Institute of Ophthalmology, Tunis, Tunisia.,Faculty of medicine, University Tunis El Manar, Tunisia
| | - Daniel F Schorderet
- Institute for Research in Ophthalmology (IRO), Sion, Switzerland.,Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland.,Jules-Gonin Eye Hospital, Faculty of biology and medicine, University of Lausanne, Switzerland
| | - Leila El Matri
- Research Laboratory of Oculogenetic (LR14SP01), Department B of Ophthalmology, Hedi Rais Institute of Ophthalmology, Tunis, Tunisia.,Faculty of medicine, University Tunis El Manar, Tunisia
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20
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Zhang L, Du J, Justus S, Hsu CW, Bonet-Ponce L, Wu WH, Tsai YT, Wu WP, Jia Y, Duong JK, Mahajan VB, Lin CS, Wang S, Hurley JB, Tsang SH. Reprogramming metabolism by targeting sirtuin 6 attenuates retinal degeneration. J Clin Invest 2016; 126:4659-4673. [PMID: 27841758 DOI: 10.1172/jci86905] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 10/06/2016] [Indexed: 12/16/2022] Open
Abstract
Retinitis pigmentosa (RP) encompasses a diverse group of Mendelian disorders leading to progressive degeneration of rods and then cones. For reasons that remain unclear, diseased RP photoreceptors begin to deteriorate, eventually leading to cell death and, consequently, loss of vision. Here, we have hypothesized that RP associated with mutations in phosphodiesterase-6 (PDE6) provokes a metabolic aberration in rod cells that promotes the pathological consequences of elevated cGMP and Ca2+, which are induced by the Pde6 mutation. Inhibition of sirtuin 6 (SIRT6), a histone deacetylase repressor of glycolytic flux, reprogrammed rods into perpetual glycolysis, thereby driving the accumulation of biosynthetic intermediates, improving outer segment (OS) length, enhancing photoreceptor survival, and preserving vision. In mouse retinae lacking Sirt6, effectors of glycolytic flux were dramatically increased, leading to upregulation of key intermediates in glycolysis, TCA cycle, and glutaminolysis. Both transgenic and AAV2/8 gene therapy-mediated ablation of Sirt6 in rods provided electrophysiological and anatomic rescue of both rod and cone photoreceptors in a preclinical model of RP. Due to the extensive network of downstream effectors of Sirt6, this study motivates further research into the role that these pathways play in retinal degeneration. Because reprogramming metabolism by enhancing glycolysis is not gene specific, this strategy may be applicable to a wide range of neurodegenerative disorders.
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21
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Cheng LL, Han RY, Yang FY, Yu XP, Xu JL, Min QJ, Tian J, Ge XL, Zheng SS, Lin YW, Zheng YH, Qu J, Gu F. Novel mutations in PDE6B causing human retinitis pigmentosa. Int J Ophthalmol 2016; 9:1094-9. [PMID: 27588261 DOI: 10.18240/ijo.2016.08.02] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 02/14/2016] [Indexed: 11/23/2022] Open
Abstract
AIM To identify the genetic defects of a Chinese patient with sporadic retinitis pigmentosa (RP). METHODS Ophthalmologic examinations were performed on the sporadic RP patient, 144 genes associated with retinal diseases were scanned with capture next generation sequencing (CNGS) approach. Two heterozygous mutations in PDE6B were confirmed in the pedigree by Sanger sequencing subsequently. The carrier frequency of PDE6B mutations of reported PDE6B mutations based on the available two public exome databases (1000 Genomes Project and ESP6500 Genomes Project) and one in-house exome database was investigated. RESULTS We identified compound heterozygosity of two novel nonsense mutations c.1133G>A (p.W378X) and c.2395C>T (p.R799X) in PDE6B, one reported causative gene for RP. Neither of the two mutations in our study was presented in three exome databases. Two mutations (p.R74C and p.T604I) in PDE6B have relatively high frequencies in the ESP6500 and in-house databases, respectively, while no common dominant mutation in each of the database or across all databases. CONCLUSION We demonstrates that compound heterozygosity of two novel nonsense mutations in PDE6B could lead to RP. These results collectively point to enormous potential of next-generation sequencing in determining the genetic etiology of RP and how various mutations in PDE6B contribute to the genetic heterogeneity of RP.
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Affiliation(s)
- Lu-Lu Cheng
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Ru-Yi Han
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Fa-Yu Yang
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Xin-Ping Yu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Jin-Ling Xu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Qing-Jie Min
- Institute of Genomic Medicine, Wenzhou Medical University, Wenzhou 325027, Zhejiang Province, China
| | - Jie Tian
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Xiang-Lian Ge
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Si-Si Zheng
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Ye-Wen Lin
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Yi-Han Zheng
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Jia Qu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
| | - Feng Gu
- School of Ophthalmology and Optometry, Eye Hospital, Wenzhou Medical University, State Key Laboratory Cultivation Base and Key Laboratory of Vision Science, Ministry of Health and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou 325027, Zhejiang Province, China
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22
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Zhang L, Justus S, Xu Y, Pluchenik T, Hsu CW, Yang J, Duong JK, Lin CS, Jia Y, Bassuk AG, Mahajan VB, Tsang SH. Reprogramming towards anabolism impedes degeneration in a preclinical model of retinitis pigmentosa. Hum Mol Genet 2016; 25:4244-4255. [PMID: 27516389 DOI: 10.1093/hmg/ddw256] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 06/25/2016] [Accepted: 07/22/2016] [Indexed: 11/14/2022] Open
Abstract
Retinitis pigmentosa (RP) is an incurable neurodegenerative condition featuring photoreceptor death that leads to blindness. Currently, there is no approved therapeutic for photoreceptor degenerative conditions like RP and atrophic age-related macular degeneration (AMD). Although there are promising results in human gene therapy, RP is a genetically diverse disorder, such that gene-specific therapies would be practical in a small fraction of patients with RP. Here, we explore a non-gene-specific strategy that entails reprogramming photoreceptors towards anabolism by upregulating the mechanistic target of rapamycin (mTOR) pathway. We conditionally ablated the tuberous sclerosis complex 1 (Tsc1) gene, an mTOR inhibitor, in the rods of the Pde6bH620Q/H620Q preclinical RP mouse model and observed, functionally and morphologically, an improvement in the survival of rods and cones at early and late disease stages. These results elucidate the ability of reprogramming the metabolome to slow photoreceptor degeneration. This strategy may also be applicable to a wider range of neurodegenerative diseases, as enhancement of nutrient uptake is not gene-specific and is implicated in multiple pathologies. Enhancing anabolism promoted neuronal survival and function and could potentially benefit a number of photoreceptor and other degenerative conditions.
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Affiliation(s)
- Lijuan Zhang
- Barbara & Donald Jonas Stem Cell & Regenerative Medicine Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Shanxi Eye Hospital, affiliated with Shanxi Medical University, Xinghualing, Taiyuan, Shanxi, China
| | - Sally Justus
- Barbara & Donald Jonas Stem Cell & Regenerative Medicine Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Yu Xu
- Barbara & Donald Jonas Stem Cell & Regenerative Medicine Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Department of Ophthalmology, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Tamara Pluchenik
- Barbara & Donald Jonas Stem Cell & Regenerative Medicine Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Chun-Wei Hsu
- Barbara & Donald Jonas Stem Cell & Regenerative Medicine Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
| | - Jin Yang
- Barbara & Donald Jonas Stem Cell & Regenerative Medicine Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA.,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA.,Tianjin Medical University Eye Hospital, Tianjin, China
| | - Jimmy K Duong
- Department of Biostatistics, Mailman School of Public Health, Columbia University Medical Center, New York, USA
| | - Chyuan-Sheng Lin
- Department of Pathology and Cell Biology, Transgenic Animal Facility, Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons of Columbia University, New York, NY, USA
| | - Yading Jia
- Shanxi Eye Hospital, affiliated with Shanxi Medical University, Xinghualing, Taiyuan, Shanxi, China
| | - Alexander G Bassuk
- Department of Pediatrics and Neurology, University of Iowa, Iowa City, IA
| | - Vinit B Mahajan
- Omics Laboratory, University of Iowa, Iowa City, IA, USA.,Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Stephen H Tsang
- Barbara & Donald Jonas Stem Cell & Regenerative Medicine Laboratory, and Bernard & Shirlee Brown Glaucoma Laboratory, Departments of Ophthalmology and Pathology & Cell Biology, Institute of Human Nutrition, Herbert Irving Comprehensive Cancer Center, Columbia University, New York, NY, USA .,Edward S. Harkness Eye Institute, New York-Presbyterian Hospital, New York, NY, USA
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23
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Chebil A, Falfoul Y, Habibi I, Munier F, Schorderet D, El Matri L. Corrélations phénotype–génotype de la rétinopathie pigmentaire non syndromique : à propos de dix familles tunisiennes. J Fr Ophtalmol 2016; 39:277-86. [DOI: 10.1016/j.jfo.2015.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/31/2015] [Accepted: 08/28/2015] [Indexed: 11/29/2022]
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AAV-mediated Gene Therapy Halts Retinal Degeneration in PDE6β-deficient Dogs. Mol Ther 2016; 24:867-76. [PMID: 26857842 DOI: 10.1038/mt.2016.37] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Accepted: 02/02/2016] [Indexed: 11/08/2022] Open
Abstract
We previously reported that subretinal injection of AAV2/5 RK.cpde6β allowed long-term preservation of photoreceptor function and vision in the rod-cone dysplasia type 1 (rcd1) dog, a large animal model of naturally occurring PDE6β deficiency. The present study builds on these earlier findings to provide a detailed assessment of the long-term effects of gene therapy on the spatiotemporal pattern of retinal degeneration in rcd1 dogs treated at 20 days of age. We analyzed the density distribution of the retinal layers and of particular photoreceptor cells in 3.5-year-old treated and untreated rcd1 dogs. Whereas no rods were observed outside the bleb or in untreated eyes, gene transfer halted rod degeneration in all vector-exposed regions. Moreover, while gene therapy resulted in the preservation of cones, glial cells and both the inner nuclear and ganglion cell layers, no cells remained in vector-unexposed retinas, except in the visual streak. Finally, the retinal structure of treated 3.5-year-old rcd1 dogs was identical to that of unaffected 4-month-old rcd1 dogs, indicating near complete preservation. Our findings indicate that gene therapy arrests the degenerative process even if intervention is initiated after the onset of photoreceptor degeneration, and point to significant potential of this therapeutic approach in future clinical trials.
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25
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Benton MC, Lea RA, Macartney-Coxson D, Hanna M, Eccles DA, Carless MA, Chambers GK, Bellis C, Goring HH, Curran JE, Harper JL, Gibson G, Blangero J, Griffiths LR. A Phenomic Scan of the Norfolk Island Genetic Isolate Identifies a Major Pleiotropic Effect Locus Associated with Metabolic and Renal Disorder Markers. PLoS Genet 2015; 11:e1005593. [PMID: 26474483 PMCID: PMC4608754 DOI: 10.1371/journal.pgen.1005593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 09/18/2015] [Indexed: 11/23/2022] Open
Abstract
Multiphenotype genome-wide association studies (GWAS) may reveal pleiotropic genes, which would remain undetected using single phenotype analyses. Analysis of large pedigrees offers the added advantage of more accurately assessing trait heritability, which can help prioritise genetically influenced phenotypes for GWAS analysis. In this study we performed a principal component analysis (PCA), heritability (h2) estimation and pedigree-based GWAS of 37 cardiovascular disease -related phenotypes in 330 related individuals forming a large pedigree from the Norfolk Island genetic isolate. PCA revealed 13 components explaining >75% of the total variance. Nine components yielded statistically significant h2 values ranging from 0.22 to 0.54 (P<0.05). The most heritable component was loaded with 7 phenotypic measures reflecting metabolic and renal dysfunction. A GWAS of this composite phenotype revealed statistically significant associations for 3 adjacent SNPs on chromosome 1p22.2 (P<1x10-8). These SNPs form a 42kb haplotype block and explain 11% of the genetic variance for this renal function phenotype. Replication analysis of the tagging SNP (rs1396315) in an independent US cohort supports the association (P = 0.000011). Blood transcript analysis showed 35 genes were associated with rs1396315 (P<0.05). Gene set enrichment analysis of these genes revealed the most enriched pathway was purine metabolism (P = 0.0015). Overall, our findings provide convincing evidence for a major pleiotropic effect locus on chromosome 1p22.2 influencing risk of renal dysfunction via purine metabolism pathways in the Norfolk Island population. Further studies are now warranted to interrogate the functional relevance of this locus in terms of renal pathology and cardiovascular disease risk. While many large genetic association studies have identified genes playing a role in complex disorders, there is still concern over the amount of missing genetic heritability. With this in mind, we have used a data reduction approach alongside pedigree-based association to obtain highly heritable components which explain 'hidden' variance of multiphenotypes within a large pedigree from the Norfolk Island genetic isolate. The most heritable of these components involved 7 traits reflecting metabolic and renal functionality, association of which locates to an intergenic region on chromosome 1p22.2. By integrating gene expression information, we identified enrichment of a purine metabolism pathway, further strengthening the metabolic nature of the observed association. Adding additional support to our approach, we show association of the tagging SNP (rs1396315) in an independent US population. The findings presented here are of particular interest as they implicate pleiotropic effect loci and newly associated biological pathways underlying cardiovascular disease risk.
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Affiliation(s)
- Miles C. Benton
- Genomics Research Centre, Institute of Biomedical Health and Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Rodney A. Lea
- Genomics Research Centre, Institute of Biomedical Health and Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Donia Macartney-Coxson
- Biomarkers Group, Kenepuru Science Centre, Institute of Environmental Science and Research, Wellington, New Zealand
| | - Michelle Hanna
- Genomics Research Centre, Institute of Biomedical Health and Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - David A. Eccles
- Genomics Research Centre, Institute of Biomedical Health and Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
| | - Melanie A. Carless
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Geoffrey K. Chambers
- School of Biological Science, Victoria University of Wellington, Wellington, New Zealand
| | - Claire Bellis
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Harald H. Goring
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Joanne E. Curran
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | | | - Gregory Gibson
- School of Biology, Georgia Institute of Technology, Atlanta, Georgia, United States of America
| | - John Blangero
- Texas Biomedical Research Institute, San Antonio, Texas, United States of America
| | - Lyn R. Griffiths
- Genomics Research Centre, Institute of Biomedical Health and Innovation, Queensland University of Technology, Brisbane, Queensland, Australia
- * E-mail:
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26
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Khan SY, Ali S, Naeem MA, Khan SN, Husnain T, Butt NH, Qazi ZA, Akram J, Riazuddin S, Ayyagari R, Hejtmancik JF, Riazuddin SA. Splice-site mutations identified in PDE6A responsible for retinitis pigmentosa in consanguineous Pakistani families. Mol Vis 2015; 21:871-82. [PMID: 26321862 PMCID: PMC4539017] [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: 08/15/2015] [Indexed: 11/02/2022] Open
Abstract
PURPOSE This study was conducted to localize and identify causal mutations associated with autosomal recessive retinitis pigmentosa (RP) in consanguineous familial cases of Pakistani origin. METHODS Ophthalmic examinations that included funduscopy and electroretinography (ERG) were performed to confirm the affectation status. Blood samples were collected from all participating individuals, and genomic DNA was extracted. A genome-wide scan was performed, and two-point logarithm of odds (LOD) scores were calculated. Sanger sequencing was performed to identify the causative variants. Subsequently, we performed whole exome sequencing to rule out the possibility of a second causal variant within the linkage interval. Sequence conservation was performed with alignment analyses of PDE6A orthologs, and in silico splicing analysis was completed with Human Splicing Finder version 2.4.1. RESULTS A large multigenerational consanguineous family diagnosed with early-onset RP was ascertained. An ophthalmic clinical examination consisting of fundus photography and electroretinography confirmed the diagnosis of RP. A genome-wide scan was performed, and suggestive two-point LOD scores were observed with markers on chromosome 5q. Haplotype analyses identified the region; however, the region did not segregate with the disease phenotype in the family. Subsequently, we performed a second genome-wide scan that excluded the entire genome except the chromosome 5q region harboring PDE6A. Next-generation whole exome sequencing identified a splice acceptor site mutation in intron 16: c.2028-1G>A, which was completely conserved in PDE6A orthologs and was absent in ethnically matched 350 control chromosomes, the 1000 Genomes database, and the NHLBI Exome Sequencing Project. Subsequently, we investigated our entire cohort of RP familial cases and identified a second family who harbored a splice acceptor site mutation in intron 10: c.1408-2A>G. In silico analysis suggested that these mutations will result in the elimination of wild-type splice acceptor sites that would result in either skipping of the respective exon or the creation of a new cryptic splice acceptor site; both possibilities would result in retinal photoreceptor cells that lack PDE6A wild-type protein. CONCLUSIONS we report two splice acceptor site variations in PDE6A in consanguineous Pakistani families who manifested cardinal symptoms of RP. Taken together with our previously published work, our data suggest that mutations in PDE6A account for about 2% of the total genetic load of RP in our cohort and possibly in the Pakistani population as well.
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Affiliation(s)
- Shahid Y. Khan
- The Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore MD
| | - Shahbaz Ali
- National Centre of Excellence in Molecular Biology, University of the Punjab, Lahore, Pakistan
| | - 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
| | - 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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27
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van Huet RAC, Pierrache LH, Meester-Smoor MA, Klaver CC, van den Born LI, Hoyng CB, de Wijs IJ, Collin RWJ, Hoefsloot LH, Klevering BJ. The efficacy of microarray screening for autosomal recessive retinitis pigmentosa in routine clinical practice. Mol Vis 2015; 21:461-76. [PMID: 25999674 PMCID: PMC4415583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 04/26/2015] [Indexed: 11/26/2022] Open
Abstract
PURPOSE To determine the efficacy of multiple versions of a commercially available arrayed primer extension (APEX) microarray chip for autosomal recessive retinitis pigmentosa (arRP). METHODS We included 250 probands suspected of arRP who were genetically analyzed with the APEX microarray between January 2008 and November 2013. The mode of inheritance had to be autosomal recessive according to the pedigree (including isolated cases). If the microarray identified a heterozygous mutation, we performed Sanger sequencing of exons and exon-intron boundaries of that specific gene. The efficacy of this microarray chip with the additional Sanger sequencing approach was determined by the percentage of patients that received a molecular diagnosis. We also collected data from genetic tests other than the APEX analysis for arRP to provide a detailed description of the molecular diagnoses in our study cohort. RESULTS The APEX microarray chip for arRP identified the molecular diagnosis in 21 (8.5%) of the patients in our cohort. Additional Sanger sequencing yielded a second mutation in 17 patients (6.8%), thereby establishing the molecular diagnosis. In total, 38 patients (15.2%) received a molecular diagnosis after analysis using the microarray and additional Sanger sequencing approach. Further genetic analyses after a negative result of the arRP microarray (n = 107) resulted in a molecular diagnosis of arRP (n = 23), autosomal dominant RP (n = 5), X-linked RP (n = 2), and choroideremia (n = 1). CONCLUSIONS The efficacy of the commercially available APEX microarray chips for arRP appears to be low, most likely caused by the limitations of this technique and the genetic and allelic heterogeneity of RP. Diagnostic yields up to 40% have been reported for next-generation sequencing (NGS) techniques that, as expected, thereby outperform targeted APEX analysis.
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Affiliation(s)
- Ramon A. C. van Huet
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Laurence H.M. Pierrache
- The Rotterdam Eye Hospital, Rotterdam, The Netherlands,Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Magda A. Meester-Smoor
- The Rotterdam Eye Hospital, Rotterdam, The Netherlands,Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Caroline C.W. Klaver
- Department of Ophthalmology, Erasmus Medical Center, Rotterdam, The Netherlands,Department of Epidemiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | | | - Carel B. Hoyng
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ilse J. de Wijs
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Rob W. J. Collin
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands,Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Lies H. Hoefsloot
- Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - B. Jeroen Klevering
- Department of Ophthalmology, Radboud University Medical Center, Nijmegen, The Netherlands
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28
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Kuniyoshi K, Sakuramoto H, Yoshitake K, Ikeo K, Furuno M, Tsunoda K, Kusaka S, Shimomura Y, Iwata T. Reduced rod electroretinograms in carrier parents of two Japanese siblings with autosomal recessive retinitis pigmentosa associated with PDE6B gene mutations. Doc Ophthalmol 2015; 131:71-9. [PMID: 25827439 DOI: 10.1007/s10633-015-9497-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 03/25/2015] [Indexed: 10/23/2022]
Abstract
PURPOSE To present the clinical and genetic findings in two siblings with autosomal recessive retinitis pigmentosa (RP) and their non-symptomatic parents. METHODS We studied two siblings, a 48-year-old woman and her 44-year-old brother, and their parents. They had general ophthalmic examinations including ophthalmoscopy, perimetry, and electroretinography (ERG). Their whole exomes were analyzed by the next-generation sequence technique. RESULTS The two siblings had night blindness for a long time, and clinical examinations revealed diffuse retinal degeneration with bone spicule pigmentation, constriction of the visual field, and non-recordable ERGs. Their parents were non-symptomatic and had normal fundi; however, their rod ERGs were reduced. Genetic examination revealed compound heterozygous mutations of I535N and H557Y in the PDE6B gene in the siblings, and the parents were heterozygous carriers of the mutations. CONCLUSIONS Heterozygous mutation in the PDE6B gene can cause a reduction in the rod function to different degrees. The retinal function of non-symptomatic carriers of autosomal recessive RP should be evaluated with care.
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Affiliation(s)
- Kazuki Kuniyoshi
- Department of Ophthalmology, Kinki University Faculty of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama City, Osaka, 589-8511, Japan,
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Zeng-Elmore X, Gao XZ, Pellarin R, Schneidman-Duhovny D, Zhang XJ, Kozacka KA, Tang Y, Sali A, Chalkley RJ, Cote RH, Chu F. Molecular architecture of photoreceptor phosphodiesterase elucidated by chemical cross-linking and integrative modeling. J Mol Biol 2014; 426:3713-3728. [PMID: 25149264 DOI: 10.1016/j.jmb.2014.07.033] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 07/01/2014] [Accepted: 07/28/2014] [Indexed: 11/20/2022]
Abstract
Photoreceptor phosphodiesterase (PDE6) is the central effector enzyme in visual excitation pathway in rod and cone photoreceptors. Its tight regulation is essential for the speed, sensitivity, recovery and adaptation of visual detection. Although major steps in the PDE6 activation/deactivation pathway have been identified, mechanistic understanding of PDE6 regulation is limited by the lack of knowledge about the molecular organization of the PDE6 holoenzyme (αβγγ). Here, we characterize the PDE6 holoenzyme by integrative structural determination of the PDE6 catalytic dimer (αβ), based primarily on chemical cross-linking and mass spectrometric analysis. Our models built from high-density cross-linking data elucidate a parallel organization of the two catalytic subunits, with juxtaposed α-helical segments within the tandem regulatory GAF domains to provide multiple sites for dimerization. The two catalytic domains exist in an open configuration when compared to the structure of PDE2 in the apo state. Detailed structural elements for differential binding of the γ-subunit to the GAFa domains of the α- and β-subunits are revealed, providing insight into the regulation of the PDE6 activation/deactivation cycle.
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Affiliation(s)
- Xiaohui Zeng-Elmore
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA; Hubbard Center for Genome Studies, University of New Hampshire, Durham, NH 03824, USA
| | - Xiong-Zhuo Gao
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Riccardo Pellarin
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - Dina Schneidman-Duhovny
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
| | - Xiu-Jun Zhang
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Katie A Kozacka
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Yang Tang
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA; Hubbard Center for Genome Studies, University of New Hampshire, Durham, NH 03824, USA
| | - Andrej Sali
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA; Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA; California Institute for Quantitative Biosciences, University of California, San Francisco, CA 94158, USA
| | - Robert J Chalkley
- Department of Pharmaceutical Chemistry, University of California, San Francisco, CA 94143, USA
| | - Rick H Cote
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Feixia Chu
- Department of Molecular, Cellular & Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA; Hubbard Center for Genome Studies, University of New Hampshire, Durham, NH 03824, USA.
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Tsang SH, Chan L, Tsai YT, Wu WH, Hsu CW, Yang J, Tosi J, Wert KJ, Davis RJ, Mahajan VB. Silencing of tuberin enhances photoreceptor survival and function in a preclinical model of retinitis pigmentosa (an american ophthalmological society thesis). TRANSACTIONS OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY 2014; 112:103-115. [PMID: 25646031 PMCID: PMC4311672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
PURPOSE To assess the functional consequences of silencing of tuberin, an inhibitor of the mTOR signaling pathway, in a preclinical model of retinitis pigmentosa (RP) in order to test the hypothesis that insufficient induction of the protein kinase B (PKB)-regulated tuberin/mTOR self-survival pathway initiates apoptosis. METHODS In an unbiased genome-scale approach, kinase peptide substrate arrays were used to analyze self-survival pathways at the onset of photoreceptor degeneration. The mutant Pde6b(H620Q)/Pde6b(H620Q) at P14 and P18 photoreceptor outer segment (OS) lysates were labeled with P-ATP and hybridized to an array of 1,164 different synthetic peptide substrates. At this stage, OS of Pde6b(H620Q)/Pde6b(H620Q) rods are morphologically normal. In vitro kinase assays and immunohistochemistry were used to validate phosphorylation. Short hairpin RNA (shRNA) gene silencing was used to validate tuberin's role in regulating survival. RESULTS At the onset of degeneration, 162 peptides were differentially phosphorylated. Protein kinases A, G, C (AGC kinases), and B exhibited increased activity in both peptide array and in vitro kinase assays. Immunohistochemical data confirmed altered phosphorylation patterns for phosphoinositide-dependent kinase-1 (PDK1), ribosomal protein S6 (RPS6), and tuberin. Tuberin gene silencing rescued photoreceptors from degeneration. CONCLUSIONS Phosphorylation of tuberin and RPS6 is due to the upregulated activity of PKB. PKB/tuberin cell growth/survival signaling is activated before the onset of degeneration. Substrates of the AGC kinases in the PKB/tuberin pathway are phosphorylated to promote cell survival. Knockdown of tuberin, the inhibitor of the mTOR pathway, increased photoreceptor survival and function in a preclinical model of RP.
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Affiliation(s)
- Stephen H Tsang
- Institute of Human Nutrition, Department of Pathology and Cell Biology and the Department of Ophthalmology, Columbia University, New York, New York
| | - Lawrence Chan
- Department of Ophthalmology, Columbia University, New York, New York
| | - Yi-Ting Tsai
- Department of Ophthalmology, Columbia University, New York, New York
| | - Wen-Hsuan Wu
- Department of Ophthalmology, Columbia University, New York, New York
| | - Chun-Wei Hsu
- Department of Ophthalmology, Columbia University, New York, New York
| | - Jin Yang
- Department of Ophthalmology, Columbia University, New York, New York; and Tianjin Medical University Eye Hospital, Tianjin, China
| | - Joaquin Tosi
- Department of Ophthalmology, Columbia University, New York, New York; and Kresge Eye Institute, Wayne State University, Detroit, Michigan
| | - Katherine J Wert
- Department of Ophthalmology, Columbia University, New York, New York; and Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Richard J Davis
- Department of Ophthalmology, Columbia University, New York, New York; and Neural Stem Cell Institute, Rensselaer, New York
| | - Vinit B Mahajan
- Omics Lab, Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, Iowa
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Shen S, Sujirakul T, Tsang SH. Next-generation sequencing revealed a novel mutation in the gene encoding the beta subunit of rod phosphodiesterase. Ophthalmic Genet 2014; 35:142-50. [PMID: 24828262 DOI: 10.3109/13816810.2014.915328] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE To report the phenotypes caused by a novel mutation in the PDE6B gene in a family with two affected siblings and one affected cousin with a 2-year follow-up. DESIGN Three patients from a family with a history of retinitis pigmentosa underwent clinical evaluations. The affected patients' DNA was analyzed using next-generation sequencing and segregation analyses were performed for the family. SETTING Edward S. Harkness Eye Institute, New York Presbyterian Hospital. PARTICIPANTS Two siblings, one cousin, and five unaffected family members. MAIN OUTCOME MEASURES Macular appearance assessed by funduscopy, autofluorescence imaging, spectral-domain optical coherence tomography and visual function assessed by electroretinography. RESULTS The proband, brother, and cousin had rod-cone degeneration with cystoid macular edema. Fundus autofluorescence showed hyperautofluorescent ring constriction over time. Spectral-domain optical coherence tomography revealed retinal pigment epithelium atrophy, loss of external limiting membrane, retinal layer thinning, and reduction in ellipsoid zone length over time. Next-generation whole exome sequencing revealed a homozygous c.1923_1969ins6del47 nonsense PDE6B mutation, which has not been previously described, that segregated with the disease in the family. CONCLUSIONS The homozygous PDE6B mutation causes retinitis pigmentosa. Acetazolamide treatment improved visual acuity but rod degeneration continued. Despite having the same mutation and living in the same environment, the proband's brother progressed at a faster rate starting at a younger age, suggesting that gene modifiers may influence the expressivity of the phenotype. Next-generation sequencing, used to discover this mutation, is a practical new technology that can detect novel disease-causing alleles, where previous arrayed primer extension (APEX) technology could not.
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Affiliation(s)
- Sherry Shen
- College of Physicians & Surgeons, Columbia University , New York, NY , USA
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Nong E, Lee W, Merriam JE, Allikmets R, Tsang SH. Disease progression in autosomal dominant cone-rod dystrophy caused by a novel mutation (D100G) in the GUCA1A gene. Doc Ophthalmol 2013; 128:59-67. [PMID: 24352742 DOI: 10.1007/s10633-013-9420-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Accepted: 12/05/2013] [Indexed: 11/30/2022]
Abstract
PURPOSE To document longitudinal fundus autofluorescence (FAF) and electroretinogram (ERG) findings in a family with cone-rod dystrophy (CRD) caused by a novel missense mutation (D100G) in the GUCA1A gene. METHODS Observational case series. RESULTS Three family members 26-49 years old underwent complete clinical examinations. In all patients, funduscopic findings showed intraretinal pigment migration, loss of neurosensory retinal pigment epithelium, and macular atrophy. FAF imaging revealed the presence of a progressive hyperautofluorescent ring around a hypoautofluorescent center corresponding to macular atrophy. Full-field ERGs showed a more severe loss of cone than rod function in each patient. Thirty-hertz flicker responses fell far below normal limits. Longitudinal FAF and ERG findings in one patient suggested progressive CRD. Two more advanced patients exhibited reduced rod response consistent with disease stage. Direct sequencing of the GUCA1A gene revealed a new missense mutation, p.Asp100Gly (D100G), in each patient. CONCLUSION Patients with autosomal dominant CRD caused by a D100G mutation in GUCA1A exhibit progressive vision loss early within the first decade of life identifiable by distinct ERG characteristics and subsequent genetic testing.
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Affiliation(s)
- Eva Nong
- Department of Ophthalmology, Columbia University, New York, NY, USA
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Bocquet B, Marzouka NAD, Hebrard M, Manes G, Sénéchal A, Meunier I, Hamel CP. Homozygosity mapping in autosomal recessive retinitis pigmentosa families detects novel mutations. Mol Vis 2013; 19:2487-500. [PMID: 24339724 PMCID: PMC3857159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/06/2013] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Autosomal recessive retinitis pigmentosa (arRP) is a genetically heterogeneous disease resulting in progressive loss of photoreceptors that leads to blindness. To date, 36 genes are known to cause arRP, rendering the molecular diagnosis a challenge. The aim of this study was to use homozygosity mapping to identify the causative mutation in a series of inbred families with arRP. METHODS arRP patients underwent standard ophthalmic examination, Goldman perimetry, fundus examination, retinal OCT, autofluorescence measurement, and full-field electroretinogram. Fifteen consanguineous families with arRP excluded for USH2A and EYS were genotyped on 250 K SNP arrays. Homozygous regions were listed, and known genes within these regions were PCR sequenced. Familial segregation and mutation analyzes were performed. RESULTS We found ten mutations, seven of which were novel mutations in eight known genes, including RP1, IMPG2, NR2E3, PDE6A, PDE6B, RLBP1, CNGB1, and C2ORF71, in ten out of 15 families. The patients carrying RP1, C2ORF71, and IMPG2 mutations presented with severe RP, while those with PDE6A, PDE6B, and CNGB1 mutations were less severely affected. The five families without mutations in known genes could be a source of identification of novel genes. CONCLUSIONS Homozygosity mapping combined with systematic screening of known genes results in a positive molecular diagnosis in 66.7% of families.
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Affiliation(s)
- Béatrice Bocquet
- INSERM U. 1051, Institute for Neurosciences of Montpellier, Montpellier, France,Université Montpellier 1, Montpellier, France,Université Montpellier 2, Montpellier, France
| | - Nour al Dain Marzouka
- INSERM U. 1051, Institute for Neurosciences of Montpellier, Montpellier, France,Université Montpellier 1, Montpellier, France,Université Montpellier 2, Montpellier, France
| | - Maxime Hebrard
- INSERM U. 1051, Institute for Neurosciences of Montpellier, Montpellier, France,Université Montpellier 1, Montpellier, France,Université Montpellier 2, Montpellier, France
| | - Gaël Manes
- INSERM U. 1051, Institute for Neurosciences of Montpellier, Montpellier, France,Université Montpellier 1, Montpellier, France,Université Montpellier 2, Montpellier, France
| | - Audrey Sénéchal
- INSERM U. 1051, Institute for Neurosciences of Montpellier, Montpellier, France,Université Montpellier 1, Montpellier, France,Université Montpellier 2, Montpellier, France
| | - Isabelle Meunier
- INSERM U. 1051, Institute for Neurosciences of Montpellier, Montpellier, France,Université Montpellier 1, Montpellier, France,Université Montpellier 2, Montpellier, France,Genetics of Sensory Diseases, CHRU, Montpellier, France
| | - Christian P. Hamel
- INSERM U. 1051, Institute for Neurosciences of Montpellier, Montpellier, France,Université Montpellier 1, Montpellier, France,Université Montpellier 2, Montpellier, France,Genetics of Sensory Diseases, CHRU, Montpellier, France
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Klamann MKJ, Maier AKB, Gonnermann J, Torun N, Ruokonen PC. [Influence of corneal thickness on intraocular pressure measurements following Descemet's stripping automated endothelial keratoplasty (DSAEK)]. Ophthalmologe 2013; 109:1093-7. [PMID: 22752628 DOI: 10.1007/s00347-012-2623-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The aim of this study was to evaluate the effect of increased corneal thickness after Descemet's stripping automated endothelial keratoplasty (DSAEK) on intraocular pressure (IOP) measured by four different techniques. METHODS In this study 30 eyes from 30 patients with successful DSAEK treatment (group 1) and 30 eyes of 30 healthy subjects (group 2) were enrolled. The IOP was measured with iCare, IOPen, Goldmann applanation tonometry (GAT) and dynamic contour tonometry (DCT) techniques. Central corneal thickness (CCT) was measured by ultrasonic pachymetry. These data were used for statistical analysis. RESULTS The mean IOP measured by GAT, DCT, iCare and IOPen was 13.2, 16.1, 12.5 and 14.2 mmHg in group 1 and 13.4, 14.4, 14.4 and 13.3 mmHg in group 2, respectively. Correlations between IOP and CCT were not statistically significant in either group. CONCLUSION The results of IOP measurements by the iCare, IOPen, GAT and DCT techniques seem to be unrelated to artificially thickened corneas after DSAEK. In spite of partially good correlation between the four techniques a direct exchange of the devices is not recommended on account of the wide dispersion of values.
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Affiliation(s)
- M K J Klamann
- Department of Ophthalmology, University Medicine Charité Berlin, Augustenburger Platz 1, 13353, Berlin, Deutschland.
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Abstract
The third-most common cause of autosomal recessive retinitis pigmentosa (RP) is due to defective cGMP phosphodiesterase-6 (PDE6). Previous work using viral gene therapy on PDE6-mutant mouse models demonstrated photoreceptors can be rescued if administered before degeneration. However, whether visual function can be rescued after degeneration onset has not been addressed. This is a clinically important question, as newly diagnosed patients exhibit considerable loss of rods and cones in their peripheral retinas. We have generated and characterized a tamoxifen inducible Cre-loxP rescue allele, Pde6b(Stop), which allows us to temporally correct PDE6-deficiency. Whereas untreated mutants exhibit degeneration, activation of Cre-loxP recombination in early embryogenesis produced stable long-term rescue. Reversal at later time-points showed partial long-term or short-lived rescue. Our results suggest stable restoration of retinal function by gene therapy can be achieved if a sufficient number of rods are treated. Because patients are generally diagnosed after extensive loss of rods, the success of clinical trials may depend on identifying patients as early as possible to maximize the number of treatable rods.
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Yang J, Naumann MC, Tsai YT, Tosi J, Erol D, Lin CS, Davis RJ, Tsang SH. Vigabatrin-induced retinal toxicity is partially mediated by signaling in rod and cone photoreceptors. PLoS One 2012; 7:e43889. [PMID: 22970106 PMCID: PMC3431405 DOI: 10.1371/journal.pone.0043889] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2012] [Accepted: 07/25/2012] [Indexed: 11/18/2022] Open
Abstract
Vigabatrin (VGB) is a commonly prescribed antiepileptic drug designed to inhibit GABA-transaminase, effectively halting seizures. Unfortunately, VGB treatment is also associated with the highest frequencies of peripheral visual field constriction of any of the antiepileptic drugs and the mechanisms that lead to these visual field defects are uncertain. Recent studies have demonstrated light exposure exacerbates vigabatrin-induced retinal toxicity. We further assessed this relationship by examining the effects of vigabatrin treatment on the retinal structures of mice with genetically altered photoreception. In keeping with previous studies, we detected increased toxicity in mice exposed to continuous light. To study whether cone or rod photoreceptor function was involved in the pathway to toxicity, we tested mice with mutations in the cone-specific Gnat2 or rod-specific Pde6g genes, and found the mutations significantly reduced VGB toxicity. Our results confirm light is a significant enhancer of vigabatrin toxicity and that a portion of this is mediated, directly or indirectly, by phototransduction signaling in rod and cone photoreceptors.
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Affiliation(s)
- Jin Yang
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
- Tianjin Medical University Eye Center, Tianjin, China
| | - Matthew C. Naumann
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Yi-Ting Tsai
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Joaquin Tosi
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Deniz Erol
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Chyuan-Sheng Lin
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
- Herbert Irving Cancer Research Center, Columbia University, New York, New York, United States of America
| | - Richard J. Davis
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
| | - Stephen H. Tsang
- Department of Ophthalmology, Columbia University, New York, New York, United States of America
- * E-mail:
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Ferrari S, Di Iorio E, Barbaro V, Ponzin D, Sorrentino FS, Parmeggiani F. Retinitis pigmentosa: genes and disease mechanisms. Curr Genomics 2012; 12:238-49. [PMID: 22131869 PMCID: PMC3131731 DOI: 10.2174/138920211795860107] [Citation(s) in RCA: 392] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 03/28/2011] [Accepted: 04/11/2011] [Indexed: 12/27/2022] Open
Abstract
Retinitis pigmentosa (RP) is a group of inherited disorders affecting 1 in 3000-7000 people and characterized by abnormalities of the photoreceptors (rods and cones) or the retinal pigment epithelium of the retina which lead to progressive visual loss. RP can be inherited in an autosomal dominant, autosomal recessive or X-linked manner. While usually limited to the eye, RP may also occur as part of a syndrome as in the Usher syndrome and Bardet-Biedl syndrome. Over 40 genes have been associated with RP so far, with the majority of them expressed in either the photoreceptors or the retinal pigment epithelium. The tremendous heterogeneity of the disease makes the genetics of RP complicated, thus rendering genotype-phenotype correlations not fully applicable yet. In addition to the multiplicity of mutations, in fact, different mutations in the same gene may cause different diseases. We will here review which genes are involved in the genesis of RP and how mutations can lead to retinal degeneration. In the future, a more thorough analysis of genetic and clinical data together with a better understanding of the genotype-phenotype correlation might allow to reveal important information with respect to the likelihood of disease development and choices of therapy.
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Oitmaa E, Peters M, Vaidla K, Andreson R, Mägi R, Slavin G, Velthut A, Tõnisson N, Reimand T, Remm M, Schneider M, Ounap K, Salumets A, Metspalu A. Molecular diagnosis of Down syndrome using quantitative APEX-2 microarrays. Prenat Diagn 2011; 30:1170-7. [PMID: 20949644 DOI: 10.1002/pd.2639] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVE To develop a new rapid and high-throughput microarray-based prenatal diagnostic test for the detection of trisomy 21 (T21). METHODS The T21 arrayed primer extension-2 (APEX-2) assay discriminates between trisomy and euploid DNA samples by comparing the signal intensities of allelic fractions of heterozygous single nucleotide polymorphisms (SNPs) after APEX reaction. After preliminary validation using DNA samples from Down syndrome patients, we analyzed DNA samples from cultured and uncultured amniocytes and chorionic villus for 90 SNPs with high heterozygosity from the 21(q21.1q22.2) region. Differences in allelic ratios of heterozygous SNPs in normal and T21 individuals were verified by t-test. RESULTS Analysis of the T21 APEX-2 assay results revealed that 90 SNPs were sufficient for reliable discrimination between T21 and euploid DNA samples (P≤0.05 for one or both strands). Using 134 clinical samples from cultured or uncultured fetal cells, both the sensitivity and the specificity of the assay were 100%. CONCLUSION Our study provides a proof of principle demonstration of the use of the modified APEX-2 assay as a new, fast and reliable method for prenatal diagnosis of fetal T21.
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Corton M, Blanco MJ, Torres M, Sanchez-Salorio M, Carracedo A, Brion M. Identification of a novel mutation in the humanPDE6Agene in autosomal recessive retinitis pigmentosa: homology with thenmf28/nmf28mice model. Clin Genet 2010; 78:495-8. [DOI: 10.1111/j.1399-0004.2010.01487.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Dvir L, Srour G, Abu-Ras R, Miller B, Shalev SA, Ben-Yosef T. Autosomal-recessive early-onset retinitis pigmentosa caused by a mutation in PDE6G, the gene encoding the gamma subunit of rod cGMP phosphodiesterase. Am J Hum Genet 2010; 87:258-64. [PMID: 20655036 DOI: 10.1016/j.ajhg.2010.06.016] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2010] [Revised: 06/21/2010] [Accepted: 06/23/2010] [Indexed: 11/28/2022] Open
Abstract
Retinitis pigmentosa (RP) is the most common form of hereditary retinal degeneration, with a worldwide prevalence of 1 in 4000. Over 30 genes and loci have been implicated in nonsyndromic autosomal-recessive (ar) RP. Genome-wide homozygosity mapping was conducted in two sibships from an extended consanguineous Muslim Arab Israeli family segregating ar severe early-onset RP. A shared homozygous region on chromosome 17q25.3 was identified in both sibships, with an overlap of 4.7 Mb. One of the genes located in this interval is PDE6G, encoding for the inhibitory gamma subunit of rod photoreceptor cyclic GMP-phosphodiesterase. Mutations in the genes encoding for the catalytic subunits of this holoenzyme, PDE6A and PDE6B, cause arRP. Sequencing of all coding exons, including exon-intron boundaries, revealed a homozygous single base change (c.187+1G>T) located in the conserved intron 3 donor splice site of PDE6G. This mutation cosegregated with the disease in the extended family. We used an in vitro splicing assay to demonstrate that this mutation leads to incorrect splicing. Affected individuals had markedly constricted visual fields. Both scotopic and photopic electroretinograms were severely reduced or completely extinct. Funduscopy showed typical bone spicule-type pigment deposits spread mainly at the midperiphery, as well as pallor of the optic disk. Macular involvement was indicated by the lack of foveal reflex and typical cystoid macular edema, proved by optical coherence tomography. These findings demonstrate the positive role of the gamma subunit in maintaining phosphodiesterase activity and confirm the contribution of PDE6G to the etiology of RP in humans.
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Affiliation(s)
- Liron Dvir
- Rappaport Family Institute for Research in the Medical Sciences, Haifa 31096, Israel
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Tosi J, Tsui I, Lima LH, Wang NK, Tsang SH. Case report: autofluorescence imaging and phenotypic variance in a sibling pair with early-onset retinal dystrophy due to defective CRB1 function. Curr Eye Res 2009; 34:395-400. [PMID: 19401883 PMCID: PMC2717950 DOI: 10.1080/02713680902859639] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE To phenotype two siblings with autosomal recessive early-onset retinal dystrophy due to CRB1 mutations. METHODS Autofluorescence (AF) imaging, high resolution optical coherence tomography (OCT), and full-field electroretinography (ERG) were performed. The results of DNA sequencing from polymerase chain reaction (PCR) products of the CRB1 gene were obtained from hospital records. RESULTS Two siblings, 14 years old and 17 years old, were compound heterozygotes for 749 del Ser and C948Y mutations in the gene encoding CRB1. AF imaging documented the preservation of retinal pigment epithelium (RPE) along the arterioles. High-resolution OCT showed abnormally thick retinae with increased lamination. CONCLUSION Leber congenital amaurosis caused by CRB1 is a unique form of early-onset retinal dystrophy because it spares the para-arteriolar RPE and causes abnormal retinal lamination with thickening. These findings, detectable with AF imaging and high-resolution OCT, can be combined with electrophysiology and genetic testing to molecularly classify retinal degenerations efficiently.
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Affiliation(s)
- Joaquin Tosi
- Bernard & Shirlee Brown Glaucoma Laboratory, Department of Ophthalmology, Columbia University, New York, New York, USA
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