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Poncet AF, Grunewald O, Vaclavik V, Meunier I, Drumare I, Pelletier V, Bocquet B, Todorova MG, Le Moing AG, Devos A, Schorderet DF, Jobic F, Defoort-Dhellemmes S, Dollfus H, Smirnov VM, Dhaenens CM. Contribution of Whole-Genome Sequencing and Transcript Analysis to Decipher Retinal Diseases Associated with MFSD8 Variants. Int J Mol Sci 2022; 23:ijms23084294. [PMID: 35457110 PMCID: PMC9032189 DOI: 10.3390/ijms23084294] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 03/25/2022] [Accepted: 04/11/2022] [Indexed: 01/01/2023] Open
Abstract
Biallelic gene defects in MFSD8 are not only a cause of the late-infantile form of neuronal ceroid lipofuscinosis, but also of rare isolated retinal degeneration. We report clinical and genetic data of seven patients compound heterozygous or homozygous for variants in MFSD8, issued from a French cohort with inherited retinal degeneration, and two additional patients retrieved from a Swiss cohort. Next-generation sequencing of large panels combined with whole-genome sequencing allowed for the identification of twelve variants from which seven were novel. Among them were one deep intronic variant c.998+1669A>G, one large deletion encompassing exon 9 and 10, and a silent change c.750A>G. Transcript analysis performed on patients’ lymphoblastoid cell lines revealed the creation of a donor splice site by c.998+1669A>G, resulting in a 140 bp pseudoexon insertion in intron 10. Variant c.750A>G produced exon 8 skipping. In silico and in cellulo studies of these variants allowed us to assign the pathogenic effect, and showed that the combination of at least one severe variant with a moderate one leads to isolated retinal dystrophy, whereas the combination in trans of two severe variants is responsible for early onset severe retinal dystrophy in the context of late-infantile neuronal ceroid lipofuscinosis.
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Affiliation(s)
- Anaïs F. Poncet
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Olivier Grunewald
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Veronika Vaclavik
- University of Lausanne, Jules-Gonin Eye Hospital, 1004 Lausanne, Switzerland;
- Cantonal Hospital, Department of Ophthalmology, 1700 Fribourg, Switzerland
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Isabelle Drumare
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Valérie Pelletier
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Béatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, F-34000 Montpellier, France; (I.M.); (B.B.)
- Institute for Neurosciences of Montpellier (INM), University of Montpellier, INSERM, F-34000 Montpellier, France
| | - Margarita G. Todorova
- Department of Ophthalmology, Cantonal Hospital, 9007 St. Gallen, Switzerland;
- Department of Ophthalmology, University of Zürich, 8091 Zürich, Switzerland
- Department of Ophthalmology, University of Basel, 4056 Basel, Switzerland
| | - Anne-Gaëlle Le Moing
- Department of Child Neurology, Amiens-Picardy University Hospital, F-80000 Amiens, France;
| | - Aurore Devos
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
| | - Daniel F. Schorderet
- Faculty of Biology and Medicine, University of Lausanne and Faculty of Life Sciences, Ecole Polytechnique Fédérale of Lausanne, 1004 Lausanne, Switzerland;
| | - Florence Jobic
- Unité de Génétique Médicale et Oncogénétique, Centre Hospitalier Universitaire Amiens Picardie, F-80000 Amiens, France;
| | - Sabine Defoort-Dhellemmes
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
| | - Hélène Dollfus
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, F-67000 Strasbourg, France; (V.P.); (H.D.)
| | - Vasily M. Smirnov
- Exploration de la Vision et Neuro-Ophtalmology, CHU de Lille, F-59000 Lille, France; (I.D.); (S.D.-D.); (V.M.S.)
- Université de Lille, Faculté de Médecine, F-59000 Lille, France
| | - Claire-Marie Dhaenens
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, F-59000 Lille, France; (A.F.P.); (O.G.); (A.D.)
- Correspondence: ; Tel.: +33-320444953
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Wang L, Sun L, Wan QH, Fang SG. Comparative Genomics Provides Insights into Adaptive Evolution in Tactile-Foraging Birds. Genes (Basel) 2022; 13:genes13040678. [PMID: 35456484 PMCID: PMC9028243 DOI: 10.3390/genes13040678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 04/07/2022] [Accepted: 04/11/2022] [Indexed: 11/28/2022] Open
Abstract
Tactile-foraging birds have evolved an enlarged principal sensory nucleus (PrV) but smaller brain regions related to the visual system, which reflects the difference in sensory dependence. The “trade-off” may exist between different senses in tactile foragers, as well as between corresponding sensory-processing areas in the brain. We explored the mechanism underlying the adaptive evolution of sensory systems in three tactile foragers (kiwi, mallard, and crested ibis). The results showed that olfaction-related genes in kiwi and mallard and hearing-related genes in crested ibis were expanded, indicating they may also have sensitive olfaction or hearing, respectively. However, some genes required for visual development were positively selected or had convergent amino acid substitutions in all three tactile branches, and it seems to show the possibility of visual degradation. In addition, we may provide a new visual-degradation candidate gene PDLIM1 who suffered dense convergent amino acid substitutions within the ZM domain. At last, two genes responsible for regulating the proliferation and differentiation of neuronal progenitor cells may play roles in determining the relative sizes of sensory areas in brain. This exploration offers insight into the relationship between specialized tactile-forging behavior and the evolution of sensory abilities and brain structures.
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53
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Hu F, Ma Y, Xu Z, Zhang S, Li J, Sun X, Wu J. Single-Cell RNA-Seq Reveals the Cellular Diversity and Developmental Characteristics of the Retinas of an Infant and a Young Child. Front Cell Dev Biol 2022; 10:803466. [PMID: 35386199 PMCID: PMC8979067 DOI: 10.3389/fcell.2022.803466] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/01/2022] [Indexed: 11/13/2022] Open
Abstract
The human retina, located in the innermost layer of the eye, plays a decisive role in visual perception. Dissecting the heterogeneity of retinal cells is essential for understanding the mechanism of visual development. Here, we performed single-cell RNA-seq to analyze 194,967 cells from the donors of infants and young children, resulting in 17 distinct clusters representing major cell types in the retina: rod photoreceptors (PRs), cone PRs, bipolar cells (BCs), horizontal cells (HCs), amacrine cells (ACs), retinal ganglion cells (RGCs), Müller glial cells (MGs), microglia, and astrocytes (ASTs). Through reclustering, we identified known subtypes of cone PRs as well as additional unreported subpopulations and corresponding markers in BCs. Additionally, we linked inherited retinal diseases (IRDs) to certain cell subtypes or subpopulations through enrichment analysis. We next constructed extensive intercellular communication networks and identified ligand-receptor interactions that play crucial roles in regulating neural cell development and immune homeostasis in the retina. Intriguingly, we found that the status and functions of PRs changed drastically between the young children and adult retina. Overall, our study offers the first retinal cell atlas in infants and young children dissecting the heterogeneity of the retina and identifying the key molecules in the developmental process, which provides an important resource that will pave the way for research on retinal development mechanisms and advancements in regenerative medicine concerning retinal biology.
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Affiliation(s)
- Fangyuan Hu
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Yuting Ma
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Zaoxu Xu
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Shenghai Zhang
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | | | - Xinghuai Sun
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
| | - Jihong Wu
- Eye Institute and Department of Ophthalmology, Eye and ENT Hospital, Fudan University, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China
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Morgan JIW, Jiang YY, Vergilio GK, Serrano LW, Pearson DJ, Bennett J, Maguire AM, Aleman TS. Short-term Assessment of Subfoveal Injection of Adeno-Associated Virus-Mediated hCHM Gene Augmentation in Choroideremia Using Adaptive Optics Ophthalmoscopy. JAMA Ophthalmol 2022; 140:411-420. [PMID: 35266957 PMCID: PMC8914909 DOI: 10.1001/jamaophthalmol.2022.0158] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Importance Subretinal injection for gene augmentation in retinal degenerations forcefully detaches the neural retina from the retinal pigment epithelium, potentially damaging photoreceptors and/or retinal pigment epithelium cells. Objective To use adaptive optics scanning light ophthalmoscopy (AOSLO) to assess the short-term integrity of the cone mosaic following subretinal injections of adeno-associated virus vector designed to deliver a functional version of the CHM gene (AAV2-hCHM) in patients with choroideremia. Design, Setting, and Participants This longitudinal case series study enrolled adult patients with choroideremia from February 2015 to January 2016 in the US. To be included in the study, study participants must have received uniocular subfoveal injections of low-dose (5 × 1010 vector genome per eye) or high-dose (1 × 1011 vector genome per eye) AAV2-hCHM. Analysis began February 2015. Main Outcomes and Measures The macular regions of both eyes were imaged before and 1 month after injection using a custom-built multimodal AOSLO. Postinjection cone inner segment mosaics were compared with preinjection mosaics at multiple regions of interest. Colocalized spectral-domain optical coherence tomography and dark-adapted cone sensitivity was also acquired at each time point. Results Nine study participants ranged in age from 26 to 50 years at the time of enrollment, and all were White men. Postinjection AOSLO images showed preservation of the cone mosaic in all 9 AAV2-hCHM-injected eyes. Mosaics appeared intact and contiguous 1 month postinjection, with the exception of foveal disruption in 1 patient. Optical coherence tomography showed foveal cone outer segment shortening postinjection. Cone-mediated sensitivities were unchanged in 8 of 9 injected and 9 of 9 uninjected eyes. One participant showed acute loss of foveal optical coherence tomography cone outer segment-related signals along with cone sensitivity loss that colocalized with disruption of the mosaic on AOSLO. Conclusions and Relevance Integrity of the cone mosaic is maintained following subretinal delivery of AAV2-hCHM, providing strong evidence in support of the safety of the injections. Minor foveal thinning observed following surgery corresponds with short-term cone outer segment shortening rather than cone cell loss. Foveal cone loss in 1 participant raises the possibility of individual vulnerability to the subretinal injection.
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Affiliation(s)
- Jessica I W Morgan
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
| | - Yu You Jiang
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
| | - Grace K Vergilio
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
| | - Leona W Serrano
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
| | - Denise J Pearson
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
| | - Jean Bennett
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
| | - Albert M Maguire
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
| | - Tomas S Aleman
- Scheie Eye Institute, University of Pennsylvania, Philadelphia.,Center for Advanced Retinal & Ocular Therapeutics, University of Pennsylvania, Philadelphia
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55
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Dvoriantchikova G, Lypka KR, Ivanov D. The Potential Role of Epigenetic Mechanisms in the Development of Retinitis Pigmentosa and Related Photoreceptor Dystrophies. Front Genet 2022; 13:827274. [PMID: 35360866 PMCID: PMC8961674 DOI: 10.3389/fgene.2022.827274] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/25/2022] [Indexed: 12/13/2022] Open
Abstract
Retinitis pigmentosa and related photoreceptor dystrophies (RPRPD) are rare retinal diseases caused by hereditary gene mutations resulting in photoreceptor death, followed by vision loss. While numerous genes involved in these diseases have been identified, many cases have still not been associated with any gene, indicating that new mechanisms may be involved in the pathogenesis of these photoreceptor dystrophies. Many genes associated with RPRPD regulate photoreceptor specification and maturation in the developing retina. Since retinal development begins with a population of equivalent, proliferating retinal progenitor cells (RPCs) having a specific “competence” in generating all types of retinal neurons, including cone and rod photoreceptors, we tested the epigenetic changes in promoters of genes required for photoreceptor development and genes associated with RPRPD during RPC differentiation into cone and rod photoreceptors. We found that promoters of many of these genes are epigenetically repressed in RPCs but have no epigenetic restrictions in photoreceptors. Our findings also suggest that DNA methylation as an epigenetic mark, and DNA demethylation as a process, are more important than other epigenetic marks or mechanisms in the pathogenesis of these diseases. Most notably, irregularities in the DNA demethylation process during the RPC-to-photoreceptor transition may significantly contribute to retinitis pigmentosa (RP) pathogenesis since genes with hypermethylated promoters in RPCs account for at least 40% of autosomal recessive RP cases and at least 30% of autosomal dominant RP cases. Thus, we proposed an epigenetic model according to which unsuccessful demethylation of regulatory sequences (e.g., promoters, enhancers) of genes required for photoreceptor development, maturation, and function during the RPC-to-photoreceptor transition may reduce or even eliminate their activity, leading to RPRPD without any inheritable mutations in these genes.
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Affiliation(s)
- Galina Dvoriantchikova
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Karin Rose Lypka
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Dmitry Ivanov
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
- Department of Microbiology and Immunology, University of Miami Miller School of Medicine, Miami, FL, United States
- *Correspondence: Dmitry Ivanov,
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56
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Neubauer J, Hahn L, Birtel J, Boon CJF, Charbel Issa P, Fischer MD. GUCY2D-Related Retinal Dystrophy with Autosomal Dominant Inheritance—A Multicenter Case Series and Review of Reported Data. Genes (Basel) 2022; 13:genes13020313. [PMID: 35205358 PMCID: PMC8872159 DOI: 10.3390/genes13020313] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 02/01/2022] [Accepted: 02/02/2022] [Indexed: 12/01/2022] Open
Abstract
To report the clinical phenotype and associated genotype of a European patient cohort with GUCY2D-related autosomal-dominant (AD) cone–/cone–rod dystrophy (COD/CORD), we retrospectively analyzed 25 patients (17 female, range 12–68) with GUCY2D-related AD-COD/CORD from three major academic centers in Europe and reviewed the previously published data of 148 patients (visual acuity (VA), foveal thickness, age of first symptoms, and genetic variant). Considering all the patients, the onset of first symptoms was reported at a median age of 7 years (interquartile range 5–19 years, n = 78), and mainly consisted of reduced VA, photophobia and color vision abnormality. The disease showed a high degree of inter-eye symmetry in terms of VA (n = 165, Spearman’s ρ = 0.85, p < 0.0001) and foveal thickness (Spearman’s ρ = 0.96, n = 38, p < 0.0001). Disease progression was assessed by plotting VA as a function of age (n = 170). A linear best-fit analysis suggested a loss of 0.17 logMAR per decade (p < 0.0001). We analyzed the largest cohort described so far (n = 173), and found that the most common mutations were p.(Arg838Cys) and p.(Arg838His). Furthermore, the majority of patients suffered severe vision loss in adulthood, highlighting a window of opportunity for potential intervention. The emerging patterns revealed by this study may aid in designing prospective natural history studies to further define endpoints for future interventional trials.
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Affiliation(s)
- Jonas Neubauer
- Centre for Ophthalmology, University Hospital Tuebingen, University of Tuebingen, 72076 Tuebingen, Germany;
- Correspondence:
| | - Leo Hahn
- Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, 1105 AZ Amsterdam, The Netherlands; (L.H.); (C.J.F.B.)
| | - Johannes Birtel
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (J.B.); (P.C.I.)
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
- Department of Ophthalmology, University Hospital Bonn, University of Bonn, 53127 Bonn, Germany
| | - Camiel J. F. Boon
- Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, 1105 AZ Amsterdam, The Netherlands; (L.H.); (C.J.F.B.)
- Department of Ophthalmology, Leiden University Medical Center, 2333 ZA Leiden, The Netherlands
| | - Peter Charbel Issa
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (J.B.); (P.C.I.)
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
| | - M. Dominik Fischer
- Centre for Ophthalmology, University Hospital Tuebingen, University of Tuebingen, 72076 Tuebingen, Germany;
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (J.B.); (P.C.I.)
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford OX3 9DU, UK
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Monferrer-Adsuara C, Montero-Hernández J, Castro-Navarro V, Remolí-Sargues L, Cervera-Taulet E. Case Report: Multimodal Imaging Features of an ABCA4 Cone Dystrophy. Optom Vis Sci 2022; 99:195-201. [PMID: 34897229 DOI: 10.1097/opx.0000000000001849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
SIGNIFICANCE Cone dystrophies and cone-rod dystrophies are a group of rare inherited pathologies characterized by degeneration of cone photoreceptors and subsequent rod involvement. The identification of causative genes is essential for diagnosis, and advanced imaging is acquiring great value in the characterization of the different phenotypic expressions. PURPOSE We describe genotype-phenotype associations of an autosomal recessive ABCA4-associated cone dystrophy using multimodal imaging. CASE REPORT A 34-year-old woman presented with progressive visual acuity decay. Visual acuity was 20/32 for her right eye and 20/25 for her left eye. A central scotoma was detected on a 10-2 Humphrey visual field in both eyes. Funduscopy revealed perifoveal retinal pigment epithelial changes, and fundus autofluorescence using blue excitation light showed decreased autofluorescence in the central fovea of both eyes with surrounding annular ring of increased autofluorescence in the perifoveal zone; green excitation light fundus autofluorescence was more accurate in the characterization of the size, perimeter, and circularity of central hypofluorescent lesions. Optical coherence tomography revealed an incomplete focal cavitation in both foveas, and optical coherence tomography angiography images showed a reduction in the superficial and deep capillary plexus density, an increased foveal avascular area, and subtle voids in choriocapillaris blood flow. Electroretinography was consistent with cone dystrophy, and molecular testing revealed the alteration of the ABCA4 gene. CONCLUSIONS The identification of an incomplete focal cavitation could alert the clinician to consider early ABCA4 central cone dystrophy. The patient in this case also exhibited reduced vessel density in the foveal area. Both of these characteristics could be important features related to the underlying genetic mutation.
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Affiliation(s)
| | | | | | - Lidia Remolí-Sargues
- Department of Ophthalmology, Hospital General Universitario de Valencia, Valencia, Spain
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Anikina E, Georgiou M, Tee J, Webster AR, Weleber RG, Michaelides M. Characterization of Retinal Function Using Microperimetry-Derived Metrics in Both Adults and Children With RPGR-Associated Retinopathy. Am J Ophthalmol 2022; 234:81-90. [PMID: 34303686 PMCID: PMC8847997 DOI: 10.1016/j.ajo.2021.07.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 07/14/2021] [Accepted: 07/14/2021] [Indexed: 11/01/2022]
Abstract
PURPOSE To investigate microperimetry testing of retinitis pigmentosa GTPase regulator gene (RPGR)-associated retinopathy in a cohort of children and adults. DESIGN Prospective observational case series. METHODS The coefficient of repeatability and intraclass correlation coefficient (ICC) of mean sensitivity (MS) were calculated for mesopic microperimetry. Best-corrected visual acuity (BCVA), contrast sensitivity (CS), MS, total volume (VTOT), and central 3-degree field volume (V3) from volumetric and topographic analyses were acquired. RESULTS The study recruited 76 individuals with RPGR (53 adults, 23 children). The mean follow-up period was 2.8 years. The ICC values for MS, VTOT, and V3 were 0.982 dB (95% CI, 0.969-0.989 dB), 0.970 dB-steradian (sr) (95% CI, -0.02658 to 0.03691 dB-sr), and 0.986 dB-sr (95% CI, 0.978-0.991), respectively. The r values for interocular MS, VTOT, and V3 were 0.97 (P < .01), 0.97 (P < .01), and 0.98 (P < .01), respectively, indicating strong interocular correlation. The interocular correlation of progression for MS, VTOT, and V3 was 0.81 (P < .01), 0.64 (P < .01), and 0.81 (P < .01), respectively. There was no statistically significant difference in the interocular progression rates for MS or VTOT. V3 did show a statistically significant difference. Most patients lost retinal sensitivity rapidly during their second and third decades of life. CONCLUSIONS The high degree of reproducibility of results and the good interocular correlation lends this method to accurately monitoring disease progression, as well as supporting validation of the use of MP in assessing the outcomes of gene therapy clinical treatment trials.
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Ekesten B, Mäkeläinen S, Ellis S, Kjellström U, Bergström TF. Abnormal Appearance of the Area Centralis in Labrador Retrievers With an ABCA4 Loss-of-function Mutation. Transl Vis Sci Technol 2022; 11:36. [PMID: 35201338 PMCID: PMC8883171 DOI: 10.1167/tvst.11.2.36] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To study retinal appearance and morphology in Labrador retrievers (LRs) heterozygous and homozygous for an ABCA4 loss-of-function mutation. METHODS Ophthalmic examination, including ophthalmoscopy and simple testing of vision, was performed in five ABCA4wt/wt, four ABCA4wt/InsC, and six ABCA4InsC/InsC LRs. Retinas were also examined with confocal scanning laser ophthalmoscopy (cSLO) and optical coherence tomography (OCT). Infrared and fundus autofluorescence (FAF) images were studied, and outer nuclear layer (ONL) and neuroretinal thickness were measured in the central and peripheral area centralis. RESULTS Clinical signs in young ABCA4InsC/InsC LRs were subtle, whereas ophthalmoscopic findings and signs of visual impairment were obvious in old ABCA4InsC/InsC LRs. Retinal appearance and vision testing was unremarkable in heterozygous LRs regardless of age. The cSLO/OCT showed abnormal morphology including ONL thinning, abnormal outer retinal layer segmentation, and focal loss of retinal pigment epithelium in the fovea equivalent in juvenile ABCA4InsC/InsC LRs. The abnormal appearance extended into the area centralis and visual streak in middle-aged ABCA4InsC/InsC and then spread more peripherally. A mild phenotype was seen on cSLO/OCT and FAF in middle-aged to old ABCA4wt/InsC LRs. CONCLUSIONS Abnormal appearance and morphology in the fovea equivalent are present in juvenile ABCA4InsC/InsC. In the older affected LRs, the visual streak and then the peripheral retina also develop an abnormal appearance. Vision deteriorates slowly, but some vision is retained throughout life. Older heterozygotes may show a mild retinal phenotype but no obvious visual impairment. The ABCA4InsC/InsC LR is a potential model for ABCA4-mediated retinopathies/juvenile-onset Stargardt disease in a species with human-sized eyes. TRANSLATIONAL RELEVANCE The ABCA4InsC mutation causes juvenile-onset abnormal appearance of the fovea equivalent in affected dogs that slowly spreads in the retina, while only a mild phenotype is seen in older carriers. This is the first non-primate, large-animal model for ABCA4-related/STGD1 retinopathies in a species with a fovea equivalent.
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Affiliation(s)
- Björn Ekesten
- Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Suvi Mäkeläinen
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.,Department of Medical Biochemistry and Microbiology, Comparative Genetics and Functional Genomics, Uppsala University, Uppsala, Sweden
| | | | | | - Tomas F Bergström
- Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden
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Chiou YR, Cheng HC, Wang AG. Astrocytic hamartoma in a patient heterozygous for RIM1 mutation associated-retinal dystrophy. Ophthalmic Genet 2022; 43:409-412. [PMID: 35014575 DOI: 10.1080/13816810.2022.2025604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
BACKGROUND Autosomal-dominant cone-rod dystrophy 7 (CORD7) has been documented in association with RIM1 mutation (c.2459 G>A). We report a patient with retinal dystrophy who was heterozygous for RIM1 missense variant with a newly found point mutation (c.4036 G>T). Clinical findings of this genetic variant manifested differently from a typical CORD7. In addition, astrocytic hamartomas at bilateral optic discs are also a unique feature, which has not been described in CORD previously. MATERIALS AND METHODS Medical records of this patient were retrospectively reviewed. Genetic testing with whole exon sequencing was performed. RESULTS This 43-year-old female with history of decreased night vision since childhood came to our hospital complaining of blurred vision in both eyes for more than half a year. Her best-corrected visual acuity was 20/200 in both eyes. Dilated fundoscopic examination revealed symmetric diffuse atrophy of retinal pigment epithelium with peripheral pigmentary clumps. Also, optic disc astrocytic hamartomas were found bilaterally. Optical coherence tomography revealed extensive disruption of inner segment/outer segment junction in both eyes. Visual field test showed severe peripheral defect sparing central vision. Electroretinogram demonstrated both rod and cone cells abnormalities. Subsequent genetic testing reported heterozygosity for the RIM1 (c.4036 G>T) mutation. CONCLUSIONS This is the first reported case of RIM1 mutation-associated retinal dystrophy with a newly found point mutation (c.4036 G>T), which presented differently from a typical CORD7 and more similarly to the phenotype of RP. Furthermore, our finding of bilateral optic disc astrocytic hamartomas has not been reported in association with CORD previously.
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Affiliation(s)
- Yi-Ran Chiou
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Hui-Chen Cheng
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - An-Guor Wang
- Department of Ophthalmology, Taipei Veterans General Hospital, Taipei, Taiwan.,School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
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Zaman S, Kane T, Katta M, Georgiou M, Michaelides M. Photoaversion in inherited retinal diseases: clinical phenotypes, biological basis, and qualitative and quantitative assessment. Ophthalmic Genet 2021; 43:143-151. [PMID: 34957896 DOI: 10.1080/13816810.2021.2015789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Severe light sensitivity is a feature common to a range of ophthalmological and neurological diseases. In inherited retinal diseases (IRDs) particularly, this may be accompanied by significant visual disruption. These symptoms are extremely debilitating for affected individuals and have significant implications in terms of day-to-day activities. Underlying mechanisms remain to be fully elucidated. Currently, there are many assessments of photoaversion (PA), however, all have limitations, with quantitative measurement in particular needing further evaluation. To understand the complexities associated with photoaversion from different pathologies, qualitative and quantitative assessments of the light aversion response must be standardized. There is no treatment to date, and strategies to alleviate symptoms focus on light avoidance. With respect to IRDs, however, gene therapy is currently being investigated in clinical trials and promising and further treatments may be on the horizon. The better characterization of these symptoms is an important end point measure in IRD gene therapy trials.
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Affiliation(s)
- Serena Zaman
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK
| | - Thomas Kane
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK
| | - Mohamed Katta
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK
| | - Michalis Georgiou
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK
| | - Michel Michaelides
- Moorfields Eye Hospital, London, UK.,UCL Institute of Ophthalmology, University College London, London, UK
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Daich Varela M, Esener B, Hashem SA, Cabral de Guimaraes TA, Georgiou M, Michaelides M. Structural evaluation in inherited retinal diseases. Br J Ophthalmol 2021; 105:1623-1631. [PMID: 33980508 PMCID: PMC8639906 DOI: 10.1136/bjophthalmol-2021-319228] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/07/2021] [Accepted: 04/21/2021] [Indexed: 12/20/2022]
Abstract
Ophthalmic genetics is a field that has been rapidly evolving over the last decade, mainly due to the flourishing of translational medicine for inherited retinal diseases (IRD). In this review, we will address the different methods by which retinal structure can be objectively and accurately assessed in IRD. We review standard-of-care imaging for these patients: colour fundus photography, fundus autofluorescence imaging and optical coherence tomography (OCT), as well as higher-resolution and/or newer technologies including OCT angiography, adaptive optics imaging, fundus imaging using a range of wavelengths, magnetic resonance imaging, laser speckle flowgraphy and retinal oximetry, illustrating their utility using paradigm genotypes with on-going therapeutic efforts/trials.
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Affiliation(s)
- Malena Daich Varela
- Moorfields Eye Hospital City Road Campus, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Burak Esener
- Department of Ophthalmology, Inonu University School of Medicine, Malatya, Turkey
| | - Shaima A Hashem
- Moorfields Eye Hospital City Road Campus, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | | | - Michalis Georgiou
- Moorfields Eye Hospital City Road Campus, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Michel Michaelides
- Moorfields Eye Hospital City Road Campus, London, UK
- UCL Institute of Ophthalmology, University College London, London, UK
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63
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Daich Varela M, Georgiou M, Hashem SA, Weleber RG, Michaelides M. Functional evaluation in inherited retinal disease. Br J Ophthalmol 2021; 106:1479-1487. [PMID: 34824084 DOI: 10.1136/bjophthalmol-2021-319994] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 10/17/2021] [Indexed: 11/03/2022]
Abstract
Functional assessments are a fundamental part of the clinical evaluation of patients with inherited retinal diseases (IRDs). Their importance and impact have become increasingly notable, given the significant breadth and number of clinical trials and studies investigating multiple avenues of intervention across a wide range of IRDs, including gene, pharmacological and cellular therapies. Moreover, the fact that many clinical trials are reporting improvements in vision, rather than the previously anticipated structural stability/slowing of degeneration, makes functional evaluation of primary relevance. In this review, we will describe a range of methods employed to characterise retinal function and functional vision, beginning with tests variably included in the clinic, such as visual acuity, electrophysiological assessment and colour discrimination, and then discussing assessments often reserved for clinical trials/research studies such as photoaversion testing, full-field static perimetry and microperimetry, and vision-guided mobility testing; addressing perimetry in greatest detail, given it is commonly a primary outcome metric. We will focus on how these tests can help diagnose and monitor particular genotypes, also noting their limitations/challenges and exploring analytical methodologies for better exploiting functional measurements, as well as how they facilitate patient inclusion and stratification in clinical trials and serve as outcome measures.
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Affiliation(s)
- Malena Daich Varela
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital City Road Campus, London, UK
| | - Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital City Road Campus, London, UK.,Department of Ophthalmology, Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Shaima A Hashem
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital City Road Campus, London, UK
| | - Richard G Weleber
- Casey Eye Institute, Oregon Health & Science University, Portland, Oregon, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK .,Moorfields Eye Hospital City Road Campus, London, UK
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Wang Y, Liu S, Zhai Y, Liu Y, Wan X, Wang W, Wang F, Sun X. Identification of a novel RPGR mutation associated with X-linked cone-rod dystrophy in a Chinese family. BMC Ophthalmol 2021; 21:401. [PMID: 34800980 PMCID: PMC8605601 DOI: 10.1186/s12886-021-02166-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 10/31/2021] [Indexed: 11/10/2022] Open
Abstract
Background Cone-rod dystrophy (CORD) is a group of inherited retinal dystrophies, characterized by decreased visual acuity, color vision defects, photophobia, and decreased sensitivity in the central visual field. Our study has identified a novel pathogenic variant associated with X-linked cone-rod dystrophy (XLCORD) in a Chinese family. Methods All six family members, including the proband, affected siblings, cousins and female carriers, have underwent thorough ophthalmic examinations. The whole exome sequencing was performed for the proband, followed by Sanger sequencing for spilt-sample validation. A mammalian expression vector (AAV-MCS) with mutated retinitis pigmentosa GTPase regulator (RPGR) sequence was expressed in HEK293 T cells. The mutated protein was verified by Western blotting and immunohistochemistry. Results A novel mutation in the RPGR gene (c.2383G > T, p.E795X) is identified to be responsible for CORD pathogenesis. Conclusions Our findings have expanded the spectrum of CORD-associated mutations in RPGR gene and serve as a basis for genetic diagnosis for X-linked CORD. Supplementary Information The online version contains supplementary material available at 10.1186/s12886-021-02166-0.
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Affiliation(s)
- Yafang Wang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China
| | - Shu Liu
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China
| | - Yuanqi Zhai
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China
| | - Yang Liu
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China
| | - Xiaoling Wan
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China
| | - Wenqiu Wang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China.
| | - Fenghua Wang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, 100 Haining Road, Shanghai, 200080, China.,Shanghai Engineering Center for Visual Science and Photomedicine, 100 Haining Road, Shanghai, 200080, China.,National Clinical Research Center for Eye Diseases, 100 Haining Road, Shanghai, 200080, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, 100 Haining Road, Shanghai, 200080, China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, 100 Haining Road, Shanghai, 200080, China.,Shanghai Key Laboratory of Ocular Fundus Diseases, 100 Haining Road, Shanghai, 200080, China.,Shanghai Engineering Center for Visual Science and Photomedicine, 100 Haining Road, Shanghai, 200080, China.,National Clinical Research Center for Eye Diseases, 100 Haining Road, Shanghai, 200080, China.,Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, 100 Haining Road, Shanghai, 200080, China
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65
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Genetic and Phenotypic Landscape of PRPH2-Associated Retinal Dystrophy in Japan. Genes (Basel) 2021; 12:genes12111817. [PMID: 34828423 PMCID: PMC8624169 DOI: 10.3390/genes12111817] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 11/14/2021] [Accepted: 11/17/2021] [Indexed: 11/29/2022] Open
Abstract
Peripherin-2 (PRPH2) is one of the causative genes of inherited retinal dystrophy. While the gene is relatively common in Caucasians, reports from Asian ethnicities are limited. In the present study, we report 40 Japanese patients from 30 families with PRPH2-associated retinal dystrophy. We identified 17 distinct pathogenic or likely pathogenic variants using next-generation sequencing. Variants p.R142W and p.V200E were relatively common in the cohort. The age of onset was generally in the 40’s; however, some patients had earlier onset (age: 5 years). Visual acuity of the patients ranged from hand motion to 1.5 (Snellen equivalent 20/13). The patients showed variable phenotypes such as retinitis pigmentosa, cone-rod dystrophy, and macular dystrophy. Additionally, intrafamilial phenotypic variability was observed. Choroidal neovascularization was observed in three eyes of two patients with retinitis pigmentosa. The results demonstrate the genotypic and phenotypic variations of the disease in the Asian cohort.
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66
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Yang J, Zhou L, Ouyang J, Xiao X, Sun W, Li S, Zhang Q. Genotype-Phenotype Analysis of RPGR Variations: Reporting of 62 Chinese Families and a Literature Review. Front Genet 2021; 12:600210. [PMID: 34745198 PMCID: PMC8565807 DOI: 10.3389/fgene.2021.600210] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Accepted: 04/27/2021] [Indexed: 02/05/2023] Open
Abstract
Purpose RPGR is the most common cause of X-linked retinitis pigmentosa (RP), of which female carriers are also frequently affected. The aim of the current study was to explore the RPGR variation spectrum and associated phenotype based on the data from our lab and previous studies. Methods Variants in RPGR were selected from exome sequencing data of 7,092 probands with different eye conditions. The probands and their available family members underwent comprehensive ocular examinations. Similar data were collected from previous reports through searches in PubMed, Web of Science, and Google Scholar. Systematic analyses of genotypes, phenotypes and their correlations were performed. Results A total of 46 likely pathogenic variants, including nine missense and one in-frame variants in RCC1-like domain and 36 truncation variants, in RPGR were detected in 62 unrelated families in our in-house cohort. In addition, a total of 585 variants, including 491 (83.9%) truncation variants, were identified from the literature. Systematic analysis of variants from our in-house dataset, literature, and gnomAD suggested that most of the pathogenic variants of RPGR were truncation variants while pathogenic missense and in-frame variants were enriched in the RCC1-like domain. Phenotypic variations were present between males and female carriers, including more severe refractive error but better best corrected visual acuity (BCVA) in female carriers than those in males. The male patients showed a significant reduction of BCVA with increase of age and males with exon1-14 variants presented a better BCVA than those with ORF15 variants. For female carriers, the BCVA also showed significant reduction with increase of age, but BCVA in females with exon1-14 variants was not significant difference compared with those with ORF15 variants. Conclusion Most pathogenic variants of RPGR are truncations. Missense and in-frame variants located outside of the RCC1-like domain might be benign and the pathogenicity criteria for these variants should be considered with greater caution. The BCVA and refractive error are different between males and female carriers. Increase of age and location of variants in ORF15 contribute to the reduction of BCVA in males. These results are valuable for understanding genotypes and phenotypes of RPGR.
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Affiliation(s)
- Junxing Yang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Lin Zhou
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Jiamin Ouyang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Xueshan Xiao
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Wenmin Sun
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Shiqiang Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
| | - Qingjiong Zhang
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China
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Biasi A, Marino V, Dal Cortivo G, Maltese PE, Modarelli AM, Bertelli M, Colombo L, Dell’Orco D. A Novel GUCA1A Variant Associated with Cone Dystrophy Alters cGMP Signaling in Photoreceptors by Strongly Interacting with and Hyperactivating Retinal Guanylate Cyclase. Int J Mol Sci 2021; 22:ijms221910809. [PMID: 34639157 PMCID: PMC8509414 DOI: 10.3390/ijms221910809] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 09/30/2021] [Accepted: 10/04/2021] [Indexed: 11/19/2022] Open
Abstract
Guanylate cyclase-activating protein 1 (GCAP1), encoded by the GUCA1A gene, is a neuronal calcium sensor protein involved in shaping the photoresponse kinetics in cones and rods. GCAP1 accelerates or slows the cGMP synthesis operated by retinal guanylate cyclase (GC) based on the light-dependent levels of intracellular Ca2+, thereby ensuring a timely regulation of the phototransduction cascade. We found a novel variant of GUCA1A in a patient affected by autosomal dominant cone dystrophy (adCOD), leading to the Asn104His (N104H) amino acid substitution at the protein level. While biochemical analysis of the recombinant protein showed impaired Ca2+ sensitivity of the variant, structural properties investigated by circular dichroism and limited proteolysis excluded major structural rearrangements induced by the mutation. Analytical gel filtration profiles and dynamic light scattering were compatible with a dimeric protein both in the presence of Mg2+ alone and Mg2+ and Ca2+. Enzymatic assays showed that N104H-GCAP1 strongly interacts with the GC, with an affinity that doubles that of the WT. The doubled IC50 value of the novel variant (520 nM for N104H vs. 260 nM for the WT) is compatible with a constitutive activity of GC at physiological levels of Ca2+. The structural region at the interface with the GC may acquire enhanced flexibility under high Ca2+ conditions, as suggested by 2 μs molecular dynamics simulations. The altered interaction with GC would cause hyper-activity of the enzyme at both low and high Ca2+ levels, which would ultimately lead to toxic accumulation of cGMP and Ca2+ in the photoreceptor outer segment, thus triggering cell death.
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Affiliation(s)
- Amedeo Biasi
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy; (A.B.); (V.M.); (G.D.C.)
| | - Valerio Marino
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy; (A.B.); (V.M.); (G.D.C.)
| | - Giuditta Dal Cortivo
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy; (A.B.); (V.M.); (G.D.C.)
| | | | - Antonio Mattia Modarelli
- Department of Ophthalmology, ASST Santi Paolo e Carlo Hospital, University of Milan, 20142 Milano, Italy;
| | - Matteo Bertelli
- MAGI’S Lab s.r.l., 38068 Rovereto, Italy; (P.E.M.); (M.B.)
- MAGI Euregio, 39100 Bolzano, Italy
| | - Leonardo Colombo
- Department of Ophthalmology, ASST Santi Paolo e Carlo Hospital, University of Milan, 20142 Milano, Italy;
- Correspondence: (L.C.); (D.D.); Tel.: +39-02-81844301 (L.C.); +39-045-802-7637 (D.D.)
| | - Daniele Dell’Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37134 Verona, Italy; (A.B.); (V.M.); (G.D.C.)
- Correspondence: (L.C.); (D.D.); Tel.: +39-02-81844301 (L.C.); +39-045-802-7637 (D.D.)
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Georgiou M, Fujinami K, Vincent A, Nasser F, Khateb S, Vargas ME, Thiadens AA, de Carvalho ER, Nguyen XTA, De Guimarães TAC, Robson AG, Mahroo OA, Pontikos N, Arno G, Fujinami-Yokokawa Y, Leo SM, Liu X, Tsunoda K, Hayashi T, Jimenez-Rolando B, Martin-Merida MI, Avila-Fernandez A, Carreño E, Garcia-Sandoval B, Ayuso C, Sharon D, Kohl S, Huckfeldt RM, Boon CJ, Banin E, Pennesi ME, Wissinger B, Webster AR, Héon E, Khan AO, Zrenner E, Michaelides M. KCNV2-Associated Retinopathy: Detailed Retinal Phenotype and Structural Endpoints-KCNV2 Study Group Report 2. Am J Ophthalmol 2021; 230:1-11. [PMID: 33737031 PMCID: PMC8710866 DOI: 10.1016/j.ajo.2021.03.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 12/01/2022]
Abstract
PURPOSE To describe the detailed retinal phenotype of KCNV2-associated retinopathy. STUDY DESIGN Multicenter international retrospective case series. METHODS Review of retinal imaging including fundus autofluorescence (FAF) and optical coherence tomography (OCT), including qualitative and quantitative analyses. RESULTS Three distinct macular FAF features were identified: (1) centrally increased signal (n = 35, 41.7%), (2) decreased autofluorescence (n = 27, 31.1%), and (3) ring of increased signal (n = 37, 44.0%). Five distinct FAF groups were identified based on combinations of those features, with 23.5% of patients changing the FAF group over a mean (range) follow-up of 5.9 years (1.9-13.1 years). Qualitative assessment was performed by grading OCT into 5 grades: (1) continuous ellipsoid zone (EZ) (20.5%); (2) EZ disruption (26.1%); (3) EZ absence, without optical gap and with preserved retinal pigment epithelium complex (21.6%); (4) loss of EZ and a hyporeflective zone at the foveola (6.8%); and (5) outer retina and retinal pigment epithelium complex loss (25.0%). Eighty-six patients had scans available from both eyes, with 83 (96.5%) having the same grade in both eyes, and 36.1% changed OCT grade over a mean follow-up of 5.5 years. The annual rate of outer nuclear layer thickness change was similar for right and left eyes. CONCLUSIONS KCNV2-associated retinopathy is a slowly progressive disease with early retinal changes, which are predominantly symmetric between eyes. The identification of a single OCT or FAF measurement as an endpoint to determine progression that applies to all patients may be challenging, although outer nuclear layer thickness is a potential biomarker. Findings suggest a potential window for intervention until 40 years of age.
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Shughoury A, Ciulla TA, Bakall B, Pennesi ME, Kiss S, Cunningham ET. Genes and Gene Therapy in Inherited Retinal Disease. Int Ophthalmol Clin 2021; 61:3-45. [PMID: 34584043 DOI: 10.1097/iio.0000000000000377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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70
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Georgiou M, Awadh Hashem S, Daich Varela M, Michaelides M. Gene Therapy in X-linked Retinitis Pigmentosa Due to Defects in RPGR. Int Ophthalmol Clin 2021; 61:97-108. [PMID: 34584047 DOI: 10.1097/iio.0000000000000384] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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The electroretinogram in the genomics era: outer retinal disorders. Eye (Lond) 2021; 35:2406-2418. [PMID: 34234290 DOI: 10.1038/s41433-021-01659-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 06/03/2021] [Accepted: 06/18/2021] [Indexed: 11/08/2022] Open
Abstract
The inherited retinal diseases (IRDs) have traditionally been described phenotypically with the description evolving to incorporate more sophisticated structural and functional assessments. In the last 25 years there has been considerable advances in the understanding of underlying genetic aetiologies. The role of the ophthalmologist is now to work in a multi-disciplinary team to identify the disease-causing genotype, which might be amenable to gene-directed intervention. Visual electrophysiology is an important tool to assist the ophthalmologist in guiding the clinical geneticist to reach a final molecular diagnosis. This review outlines the physiological basis for the ISCEV standard electrophysiology tests, the role of electrophysiology in localising the functional deficit, correlation with structural findings to guide diagnosis and finally management of IRDs in the era of genomics with emphasis on the outer retina.
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Dohlman JC, Chwalisz BK, Stephen CD. Clinical Reasoning: A 28-Year-Old Woman With Vision Loss and an Unusual Gait. Neurology 2021; 97:e1860-e1865. [PMID: 34187863 DOI: 10.1212/wnl.0000000000012446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Jenny C Dohlman
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Harvard Medical School, Boston, MA
| | - Bart K Chwalisz
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary/Harvard Medical School, Boston, MA.,Department of Neurology, Massachusetts General Hospital, Boston, MA
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Wang Y, Li X, Yu Y, Liang J, Liu Y, Chen Y, Bai X, Chen J, Wang F, Luo X, Sun X. Modeling Cone/Cone-Rod Dystrophy Pathology by AAV-Mediated Overexpression of Mutant CRX Protein in the Mouse Retina. Transl Vis Sci Technol 2021; 10:25. [PMID: 34144598 PMCID: PMC8237110 DOI: 10.1167/tvst.10.7.25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose This study aims to evaluate the pathogenesis of cone/cone–rod dystrophy (CoD/CoRD) caused by a cone–rod homeobox (CRX) mutation, which was identified in a Chinese family, through adeno-associated virus (AAV)-mediated overexpression of mutant CRX protein in the mouse retina. Methods Comprehensive ophthalmologic examinations were performed for the pedigree members of a Chinese family with CoD/CoRD. Whole exome sequencing and Sanger sequencing were performed to determine the genetic cause of the disease. Furthermore, AAV vectors were used to construct AAV-CRX-mut-HA, which was transfected into mouse photoreceptor cells to clarify the pathogenesis of the mutant CRX. Results Fundus photography and optical coherence tomography images displayed features that were consistent with CoD/CoRD, including macular atrophy and photoreceptor layer thinning. Electroretinogram analysis indicated an obvious decrease in photopic responses or both scotopic and photopic responses in affected individuals. A frameshift variant c.611delC (p.S204fs) in CRX was cosegregated with the disease in this family. AAV-CRX-mut-HA that subretinally injected into the C57BL/6 mice generally transfected the outer nuclear layer, leading to the loss of cone and rod photoreceptor cells, abnormal expression of CRX target genes, and a decrease in electroretinogram responses. Conclusions AAV-mediated overexpression of CRX[S204fs] in the mouse retina led to a CoRD-like phenotype and showed the possible pathogenesis of the antimorphic CRX mutation. Translational Relevance This study provides a modeling method to evaluate the pathogenesis of CoD/CoRD and other inherited retinal dystrophies caused by distinct gain-of-function mutations.
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Affiliation(s)
- Yuwei Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Xiaomeng Li
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Yang Yu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jian Liang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Yang Liu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Yuhong Chen
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Xinyue Bai
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Jieqiong Chen
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China
| | - Fenghua Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
| | - Xueting Luo
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China
| | - Xiaodong Sun
- Department of Ophthalmology, Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Fundus Diseases, Shanghai, China.,National Clinical Research Center for Eye Diseases, Shanghai, China.,Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
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Smirnov V, Grunewald O, Muller J, Zeitz C, Obermaier CD, Devos A, Pelletier V, Bocquet B, Andrieu C, Bacquet JL, Lebredonchel E, Mohand-Saïd S, Defoort-Dhellemmes S, Sahel JA, Dollfus H, Zanlonghi X, Audo I, Meunier I, Boulanger-Scemama E, Dhaenens CM. Novel TTLL5 Variants Associated with Cone-Rod Dystrophy and Early-Onset Severe Retinal Dystrophy. Int J Mol Sci 2021; 22:ijms22126410. [PMID: 34203883 PMCID: PMC8232641 DOI: 10.3390/ijms22126410] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/07/2021] [Accepted: 06/09/2021] [Indexed: 01/05/2023] Open
Abstract
Variants of the TTLL5 gene, which encodes tubulin tyrosine ligase-like family member five, are a rare cause of cone dystrophy (COD) or cone-rod dystrophy (CORD). To date, only a few TTLL5 patients have been clinically and genetically described. In this study, we report five patients harbouring biallelic variants of TTLL5. Four adult patients presented either COD or CORD with onset in the late teenage years. The youngest patient had a phenotype of early onset severe retinal dystrophy (EOSRD). Genetic analysis was performed by targeted next generation sequencing of gene panels and assessment of copy number variants (CNV). We identified eight variants, of which six were novel, including two large multiexon deletions in patients with COD or CORD, while the EOSRD patient harboured the novel homozygous p.(Trp640*) variant and three distinct USH2A variants, which might explain the observed rod involvement. Our study highlights the role of TTLL5 in COD/CORD and the importance of large deletions. These findings suggest that COD or CORD patients lacking variants in known genes may harbour CNVs to be discovered in TTLL5, previously undetected by classical sequencing methods. In addition, variable phenotypes in TTLL5-associated patients might be due to the presence of additional gene defects.
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Affiliation(s)
- Vasily Smirnov
- Université de Lille, Faculté de Médecine, 59037 Lille, France;
- CHU Lille, Service d’Exploration Fonctionnelle de la Vision et de Neuro-Ophtalmologie, Hôpital Salengro, 59037 Lille, France;
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
| | - Olivier Grunewald
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, 59045 Lille, France;
| | - Jean Muller
- Laboratoire de Génétique Médicale, Institut de Génétique Médicale d’Alsace (IGMA), INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Université de Strasbourg UMRS_1112, 67000 Strasbourg, France;
- Laboratoire de Diagnostic Génétique, Hôpitaux Universitaires de Strasbourg, Institut de Génétique Médicale d’Alsace (IGMA), 67000 Strasbourg, France
| | - Christina Zeitz
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
| | - Carolin D. Obermaier
- Praxis für Humangenetik Tuebingen & Center for Genomics and Transcriptomics, CeGaT GmbH, 72076 Tuebingen, Germany;
| | - Aurore Devos
- Univ. Lille, CHU Lille, Service de Toxicologie et Génopathies, 59037 Lille, France; (A.D.); (E.L.)
| | - Valérie Pelletier
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (V.P.); (J.-L.B.); (H.D.)
| | - Béatrice Bocquet
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, 34295 Montpellier, France; (B.B.); (I.M.)
- Institute for Neurosciences of Montpellier (INM), INSERM, University of Montpellier, INSERM, 34295 Montpellier, France
| | - Camille Andrieu
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
| | - Jean-Louis Bacquet
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (V.P.); (J.-L.B.); (H.D.)
| | - Elodie Lebredonchel
- Univ. Lille, CHU Lille, Service de Toxicologie et Génopathies, 59037 Lille, France; (A.D.); (E.L.)
| | - Saddek Mohand-Saïd
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
| | - Sabine Defoort-Dhellemmes
- CHU Lille, Service d’Exploration Fonctionnelle de la Vision et de Neuro-Ophtalmologie, Hôpital Salengro, 59037 Lille, France;
| | - José-Alain Sahel
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
- Fondation Ophtalmologique Adolphe de Rothschild, 75019 Paris, France;
- Department of Ophthalmology, The University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Hélène Dollfus
- Centre de Référence pour les Affections Rares en Génétique Ophtalmologiques, Hopitaux Universitaires de Strasbourg, 67000 Strasbourg, France; (V.P.); (J.-L.B.); (H.D.)
| | | | - Isabelle Audo
- Sorbonne Université, INSERM, CNRS, Institut de la Vision, 75012 Paris, France; (C.Z.); (S.M.-S.); (J.-A.S.); (I.A.)
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, INSERM-DHOS CIC 1423, 75012 Paris, France;
- Institute of Ophthalmology, University College London, London EC1V 9EL, UK
| | - Isabelle Meunier
- National Reference Centre for Inherited Sensory Diseases, University of Montpellier, Montpellier University Hospital, Sensgene Care Network, ERN-EYE Network, 34295 Montpellier, France; (B.B.); (I.M.)
- Institute for Neurosciences of Montpellier (INM), INSERM, University of Montpellier, INSERM, 34295 Montpellier, France
| | | | - Claire-Marie Dhaenens
- Univ. Lille, Inserm, CHU Lille, U1172-LilNCog-Lille Neuroscience & Cognition, 59045 Lille, France;
- Correspondence: ; Tel.: +33-320-444-953
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75
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Grześk G, Nowaczyk A. Current Modulation of Guanylate Cyclase Pathway Activity-Mechanism and Clinical Implications. Molecules 2021; 26:molecules26113418. [PMID: 34200064 PMCID: PMC8200204 DOI: 10.3390/molecules26113418] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/25/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023] Open
Abstract
For years, guanylate cyclase seemed to be homogenic and tissue nonspecific enzyme; however, in the last few years, in light of preclinical and clinical trials, it became an interesting target for pharmacological intervention. There are several possible options leading to an increase in cyclic guanosine monophosphate concentrations. The first one is related to the uses of analogues of natriuretic peptides. The second is related to increasing levels of natriuretic peptides by the inhibition of degradation. The third leads to an increase in cyclic guanosine monophosphate concentration by the inhibition of its degradation by the inhibition of phosphodiesterase type 5. The last option involves increasing the concentration of cyclic guanosine monophosphate by the additional direct activation of soluble guanylate cyclase. Treatment based on the modulation of guanylate cyclase function is one of the most promising technologies in pharmacology. Pharmacological intervention is stable, effective and safe. Especially interesting is the role of stimulators and activators of soluble guanylate cyclase, which are able to increase the enzymatic activity to generate cyclic guanosine monophosphate independently of nitric oxide. Moreover, most of these agents are effective in chronic treatment in heart failure patients and pulmonary hypertension, and have potential to be a first line option.
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Affiliation(s)
- Grzegorz Grześk
- Department of Cardiology and Clinical Pharmacology, Faculty of Health Sciences, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, 75 Ujejskiego St., 85-168 Bydgoszcz, Poland;
| | - Alicja Nowaczyk
- Department of Organic Chemistry, Faculty of Pharmacy, Ludwik Rydygier Collegium Medicum in Bydgoszcz, Nicolaus Copernicus University in Toruń, 2 dr. A. Jurasza St., 85-094 Bydgoszcz, Poland
- Correspondence: ; Tel.: +48-52-585-3904
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76
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Georgiou M, Robson AG, Fujinami K, Leo SM, Vincent A, Nasser F, Cabral De Guimarães TA, Khateb S, Pontikos N, Fujinami-Yokokawa Y, Liu X, Tsunoda K, Hayashi T, Vargas ME, Thiadens AAHJ, de Carvalho ER, Nguyen XTA, Arno G, Mahroo OA, Martin-Merida MI, Jimenez-Rolando B, Gordo G, Carreño E, Ayuso C, Sharon D, Kohl S, Huckfeldt RM, Wissinger B, Boon CJF, Banin E, Pennesi ME, Khan AO, Webster AR, Zrenner E, Héon E, Michaelides M. KCNV2-Associated Retinopathy: Genetics, Electrophysiology, and Clinical Course-KCNV2 Study Group Report 1. Am J Ophthalmol 2021; 225:95-107. [PMID: 33309813 PMCID: PMC8186730 DOI: 10.1016/j.ajo.2020.11.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 11/18/2020] [Accepted: 11/25/2020] [Indexed: 12/01/2022]
Abstract
PURPOSE To investigate genetics, electrophysiology, and clinical course of KCNV2-associated retinopathy in a cohort of children and adults. STUDY DESIGN This was a multicenter international clinical cohort study. METHODS Review of clinical notes and molecular genetic testing. Full-field electroretinography (ERG) recordings, incorporating the international standards, were reviewed and quantified and compared with age and recordings from control subjects. RESULTS In total, 230 disease-associated alleles were identified from 117 patients, corresponding to 75 different KCNV2 variants, with 28 being novel. The mean age of onset was 3.9 years old. All patients were symptomatic before 12 years of age (range, 0-11 years). Decreased visual acuity was present in all patients, and 4 other symptoms were common: reduced color vision (78.6%), photophobia (53.5%), nyctalopia (43.6%), and nystagmus (38.6%). After a mean follow-up of 8.4 years, the mean best-corrected visual acuity (BCVA ± SD) decreased from 0.81 ± 0.27 to 0.90 ± 0.31 logarithm of minimal angle of resolution. Full-field ERGs showed pathognomonic waveform features. Quantitative assessment revealed a wide range of ERG amplitudes and peak times, with a mean rate of age-associated reduction indistinguishable from the control group. Mean amplitude reductions for the dark-adapted 0.01 ERG, dark-adapted 10 ERG a-wave, and LA 3.0 30 Hz and LA3 ERG b-waves were 55%, 21%, 48%, and 74%, respectively compared with control values. Peak times showed stability across 6 decades. CONCLUSION In KCNV2-associated retinopathy, full-field ERGs are diagnostic and consistent with largely stable peripheral retinal dysfunction. Report 1 highlights the severity of the clinical phenotype and established a large cohort of patients, emphasizing the unmet need for trials of novel therapeutics.
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Affiliation(s)
- Michalis Georgiou
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom
| | - Anthony G Robson
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom
| | - Kaoru Fujinami
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom; Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan; Department of Ophthalmology, Keio University School of Medicine, Tokyo, Ontario, Japan
| | - Shaun M Leo
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom
| | - Ajoy Vincent
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Fadi Nasser
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | | | - Samer Khateb
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nikolas Pontikos
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom
| | - Yu Fujinami-Yokokawa
- University College London Institute of Ophthalmology, London, United Kingdom; Department of Health Policy and Management, Keio University School of Medicine, Tokyo, Japan
| | - Xiao Liu
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan; Department of Ophthalmology, Keio University School of Medicine, Tokyo, Ontario, Japan
| | - Kazushige Tsunoda
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan; Department of Ophthalmology, Keio University School of Medicine, Tokyo, Ontario, Japan
| | - Takaaki Hayashi
- Department of Ophthalmology, Katsushika Medical Center, The Jikei University School of Medicine, Tokyo, Japan
| | - Mauricio E Vargas
- Department of Ophthalmology, Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, USA
| | | | - Emanuel R de Carvalho
- University College London Institute of Ophthalmology, London, United Kingdom; Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, Amsterdam, the Netherlands
| | - Xuan-Thanh-An Nguyen
- Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
| | - Gavin Arno
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom
| | - Omar A Mahroo
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom
| | - Maria Inmaculada Martin-Merida
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid, Madrid, Spain; Center for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Belen Jimenez-Rolando
- Department of Ophthalmology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid, Madrid, Spain
| | - Gema Gordo
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid, Madrid, Spain; Center for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Ester Carreño
- Department of Ophthalmology, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid, Madrid, Spain
| | - Carmen Ayuso
- Department of Genetics, Instituto de Investigación Sanitaria-Fundación Jiménez Díaz University Hospital-Universidad Autónoma de Madrid, Madrid, Spain; Center for Biomedical Network Research on Rare Diseases, Instituto de Salud Carlos III, Madrid, Spain
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Rachel M Huckfeldt
- Department of Ophthalmology, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Camiel J F Boon
- Department of Ophthalmology, Amsterdam UMC, Academic Medical Center, Amsterdam, the Netherlands; Department of Ophthalmology, Leiden University Medical Center, Leiden, the Netherlands
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Medical Center, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mark E Pennesi
- Department of Ophthalmology, Oregon Health and Science University, Casey Eye Institute, Portland, Oregon, USA
| | - Arif O Khan
- Department of Ophthalmology, Cleveland Clinic Lerner College of Medicine of Case Western University, Cleveland, Ohio, USA; Eye Institute, Cleveland Clinic Abu Dhabi, Abu Dhabi, United Arab Emirates
| | - Andrew R Webster
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Elise Héon
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Michel Michaelides
- Moorfields Eye Hospital, London, United Kingdom; University College London Institute of Ophthalmology, London, United Kingdom.
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Kohl S, Llavona P, Sauer A, Reuter P, Weisschuh N, Kempf M, Dehmelt FA, Arrenberg AB, Sliesoraityte I, Zrenner E, van Schooneveld MJ, Rudolph G, Kühlewein L, Wissinger B. A duplication on chromosome 16q12 affecting the IRXB gene cluster is associated with autosomal dominant cone dystrophy with early tritanopic color vision defect. Hum Mol Genet 2021; 30:1218-1229. [PMID: 33891002 PMCID: PMC8212766 DOI: 10.1093/hmg/ddab117] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 04/15/2021] [Accepted: 04/15/2021] [Indexed: 02/06/2023] Open
Abstract
Cone dystrophies are a rare subgroup of inherited retinal dystrophies and hallmarked by color vision defects, low or decreasing visual acuity and central vision loss, nystagmus and photophobia. Applying genome-wide linkage analysis and array comparative genome hybridization, we identified a locus for autosomal dominant cone dystrophy on chromosome 16q12 in four independent multigeneration families. The locus is defined by duplications of variable size with a smallest region of overlap of 608 kb affecting the IRXB gene cluster and encompasses the genes IRX5 and IRX6. IRX5 and IRX6 belong to the Iroquois (Iro) protein family of homeodomain-containing transcription factors involved in patterning and regionalization of embryonic tissue in vertebrates, including the eye and the retina. All patients presented with a unique progressive cone dystrophy phenotype hallmarked by early tritanopic color vision defects. We propose that the disease underlies a misregulation of the IRXB gene cluster on chromosome 16q12 and demonstrate that overexpression of Irx5a and Irx6a, the two orthologous genes in zebrafish, results in visual impairment in 5-day-old zebrafish larvae.
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Affiliation(s)
- Susanne Kohl
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Pablo Llavona
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Alexandra Sauer
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Peggy Reuter
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Nicole Weisschuh
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Melanie Kempf
- University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Universitätsklinikum Tübingen, Tübingen 72076, Germany.,Center for Rare Eye Diseases, University of Tübingen, Tübingen 72076, Germany
| | - Florian Alexander Dehmelt
- Werner Reichardt Centre for Integrative Neuroscience and Institute of Neurobiology, University of Tübingen, Tübingen 72076, Germany
| | - Aristides B Arrenberg
- Werner Reichardt Centre for Integrative Neuroscience and Institute of Neurobiology, University of Tübingen, Tübingen 72076, Germany
| | - Ieva Sliesoraityte
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
| | - Eberhart Zrenner
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany.,Werner Reichardt Centre for Integrative Neuroscience and Institute of Neurobiology, University of Tübingen, Tübingen 72076, Germany
| | - Mary J van Schooneveld
- Department of Ophthalmology, Amsterdam University Medical Centre, Amsterdam 1100 DD, The Netherlands.,Bartiméus Diagnostic Department, Zeist, The Netherlands
| | - Günther Rudolph
- Department of Ophthalmology, University Hospital, LMU Munich, München 80336, Germany
| | - Laura Kühlewein
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany.,University Eye Hospital, Centre for Ophthalmology, University of Tübingen, Universitätsklinikum Tübingen, Tübingen 72076, Germany
| | - Bernd Wissinger
- Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen 72076, Germany
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78
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Unique Variant Spectrum in a Jordanian Cohort with Inherited Retinal Dystrophies. Genes (Basel) 2021; 12:genes12040593. [PMID: 33921607 PMCID: PMC8074154 DOI: 10.3390/genes12040593] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2021] [Revised: 04/07/2021] [Accepted: 04/14/2021] [Indexed: 12/12/2022] Open
Abstract
Whole Exome Sequencing (WES) is a powerful approach for detecting sequence variations in the human genome. The aim of this study was to investigate the genetic defects in Jordanian patients with inherited retinal dystrophies (IRDs) using WES. WES was performed on proband patients' DNA samples from 55 Jordanian families. Sanger sequencing was used for validation and segregation analysis of the detected, potential disease-causing variants (DCVs). Thirty-five putatively causative variants (6 novel and 29 known) in 21 IRD-associated genes were identified in 71% of probands (39 of the 55 families). Three families showed phenotypes different from the typically reported clinical findings associated with the causative genes. To our knowledge, this is the largest genetic analysis of IRDs in the Jordanian population to date. Our study also confirms that WES is a powerful tool for the molecular diagnosis of IRDs in large patient cohorts.
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79
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Marino V, Dal Cortivo G, Maltese PE, Placidi G, De Siena E, Falsini B, Bertelli M, Dell’Orco D. Impaired Ca 2+ Sensitivity of a Novel GCAP1 Variant Causes Cone Dystrophy and Leads to Abnormal Synaptic Transmission Between Photoreceptors and Bipolar Cells. Int J Mol Sci 2021; 22:ijms22084030. [PMID: 33919796 PMCID: PMC8070792 DOI: 10.3390/ijms22084030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Revised: 04/06/2021] [Accepted: 04/09/2021] [Indexed: 01/23/2023] Open
Abstract
Guanylate cyclase-activating protein 1 (GCAP1) is involved in the shutdown of the phototransduction cascade by regulating the enzymatic activity of retinal guanylate cyclase via a Ca2+/cGMP negative feedback. While the phototransduction-associated role of GCAP1 in the photoreceptor outer segment is widely established, its implication in synaptic transmission to downstream neurons remains to be clarified. Here, we present clinical and biochemical data on a novel isolate GCAP1 variant leading to a double amino acid substitution (p.N104K and p.G105R) and associated with cone dystrophy (COD) with an unusual phenotype. Severe alterations of the electroretinogram were observed under both scotopic and photopic conditions, with a negative pattern and abnormally attenuated b-wave component. The biochemical and biophysical analysis of the heterologously expressed N104K-G105R variant corroborated by molecular dynamics simulations highlighted a severely compromised Ca2+-sensitivity, accompanied by minor structural and stability alterations. Such differences reflected on the dysregulation of both guanylate cyclase isoforms (RetGC1 and RetGC2), resulting in the constitutive activation of both enzymes at physiological levels of Ca2+. As observed with other GCAP1-associated COD, perturbation of the homeostasis of Ca2+ and cGMP may lead to the toxic accumulation of second messengers, ultimately triggering cell death. However, the abnormal electroretinogram recorded in this patient also suggested that the dysregulation of the GCAP1–cyclase complex further propagates to the synaptic terminal, thereby altering the ON-pathway related to the b-wave generation. In conclusion, the pathological phenotype may rise from a combination of second messengers’ accumulation and dysfunctional synaptic communication with bipolar cells, whose molecular mechanisms remain to be clarified.
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Affiliation(s)
- Valerio Marino
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37129 Verona, Italy; (V.M.); (G.D.C.)
| | - Giuditta Dal Cortivo
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37129 Verona, Italy; (V.M.); (G.D.C.)
| | | | - Giorgio Placidi
- Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, 00168 Rome, Italy; (G.P.); (E.D.S.)
- Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Elisa De Siena
- Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, 00168 Rome, Italy; (G.P.); (E.D.S.)
- Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | - Benedetto Falsini
- Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, 00168 Rome, Italy; (G.P.); (E.D.S.)
- Università Cattolica del Sacro Cuore, 00168 Rome, Italy
- Correspondence: (B.F.); (D.D.); Tel.: +39-06-3015-6344 (B.F.); +39-045-802-7637 (D.D.)
| | - Matteo Bertelli
- MAGI’S Lab S.R.L., 38068 Rovereto, Italy; (P.E.M.); (M.B.)
- MAGI Euregio, 39100 Bolzano, Italy
| | - Daniele Dell’Orco
- Department of Neurosciences, Biomedicine and Movement Sciences, Section of Biological Chemistry, University of Verona, 37129 Verona, Italy; (V.M.); (G.D.C.)
- Correspondence: (B.F.); (D.D.); Tel.: +39-06-3015-6344 (B.F.); +39-045-802-7637 (D.D.)
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Hadalin V, Šuštar M, Volk M, Maver A, Sajovic J, Jarc-Vidmar M, Peterlin B, Hawlina M, Fakin A. Cone Dystrophy Associated with a Novel Variant in the Terminal Codon of the RPGR- ORF15. Genes (Basel) 2021; 12:genes12040499. [PMID: 33805381 PMCID: PMC8066792 DOI: 10.3390/genes12040499] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/30/2022] Open
Abstract
Mutations in RPGRORF15 are associated with rod-cone or cone/cone-rod dystrophy, the latter associated with mutations at the distal end. We describe the phenotype associated with a novel variant in the terminal codon of the RPGRORF15 c.3457T>A (Ter1153Lysext*38), which results in a C-terminal extension. Three male patients from two families were recruited, aged 31, 35, and 38 years. Genetic testing was performed by whole exome sequencing. Filtered variants were analysed according to the population frequency, ClinVar database, the variant’s putative impact, and predicted pathogenicity; and were classified according to the ACMG guidelines. Examination included visual acuity (Snellen), colour vision (Ishihara), visual field, fundus autofluorescence (FAF), optical coherence tomography (OCT), and electrophysiology. All patients were myopic, and had central scotoma and reduced colour vision. Visual acuities on better eyes were counting fingers, 0.3 and 0.05. Electrophysiology showed severely reduced cone-specific responses and macular dysfunction, while the rod-specific response was normal. FAF showed hyperautofluorescent ring centred at the fovea encompassing an area of photoreceptor loss approximately two optic discs in diameter (3462–6342 μm). Follow up after 2–11 years showed enlargement of the diameter (avg. 100 μm/year). The novel c.3457T>A (Ter1153Lysext*38) mutation in the terminal RPGRORF15 codon is associated with cone dystrophy, which corresponds to the previously described phenotypes associated with mutations in the distal end of the RPGRORF15. Minimal progression during follow-up years suggests a relatively stable disease after the initial loss of the central cones.
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Affiliation(s)
- Vlasta Hadalin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Maja Šuštar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Marija Volk
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Aleš Maver
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Jana Sajovic
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Martina Jarc-Vidmar
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Borut Peterlin
- Clinical Institute of Medical Genetics, University Medical Centre Ljubljana, Šlajmerjeva ulica 4, 1000 Ljubljana, Slovenia; (M.V.); (A.M.); (B.P.)
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, Grablovičeva 46, 1000 Ljubljana, Slovenia; (V.H.); (M.Š.); (J.S.); (M.J.-V.); (M.H.)
- Correspondence:
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81
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Impairments of Photoreceptor Outer Segments Renewal and Phototransduction Due to a Peripherin Rare Haplotype Variant: Insights from Molecular Modeling. Int J Mol Sci 2021; 22:ijms22073484. [PMID: 33801777 PMCID: PMC8036374 DOI: 10.3390/ijms22073484] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Retinitis pigmentosa punctata albescens (RPA) is a particular form of retinitis pigmentosa characterized by childhood onset night blindness and areas of peripheral retinal atrophy. We investigated the genetic cause of RPA in a family consisting of two affected Egyptian brothers with healthy consanguineous parents. METHODS Mutational analysis of four RPA causative genes was realized by Sanger sequencing on both probands, and detected variants were subsequently genotyped in their parents. Afterwards, found variants were deeply, statistically, and in silico characterized to determine their possible effects and association with RPA. RESULTS Both brothers carry three missense PRPH2 variants in a homozygous condition (c.910C > A, c.929G > A, and c.1013A > C) and two promoter variants in RHO (c.-26A > G) and RLBP1 (c.-70G > A) genes, respectively. Haplotype analyses highlighted a PRPH2 rare haplotype variant (GAG), determining a possible alteration of PRPH2 binding with melanoregulin and other outer segment proteins, followed by photoreceptor outer segment instability. Furthermore, an altered balance of transcription factor binding sites, due to the presence of RHO and RLBP1 promoter variants, might determine a comprehensive downregulation of both genes, possibly altering the PRPH2 shared visual-related pathway. CONCLUSIONS Despite several limitations, the study might be a relevant step towards detection of novel scenarios in RPA etiopathogenesis.
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The need for widely available genomic testing in rare eye diseases: an ERN-EYE position statement. Orphanet J Rare Dis 2021; 16:142. [PMID: 33743793 PMCID: PMC7980559 DOI: 10.1186/s13023-021-01756-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Accepted: 02/18/2021] [Indexed: 12/26/2022] Open
Abstract
Background Rare Eye Diseases (RED) are the leading cause of visual impairment and blindness for children and young adults in Europe. This heterogeneous group of conditions includes over 900 disorders ranging from relatively prevalent disorders such as retinitis pigmentosa to very rare entities such as developmental eye anomalies. A significant number of patients with RED have an underlying genetic etiology. One of the aims of the European Reference Network for Rare Eye Diseases (ERN–EYE) is to facilitate improvement in diagnosis of RED in European member states. Main body Technological advances have allowed genetic and genomic testing for RED. The outcome of genetic testing allows better understanding of the condition and allows reproductive and therapeutic options. The increase of the number of clinical trials for RED has provided urgency for genetic testing in RED. A survey of countries participating in ERN-EYE demonstrated that the majority are able to access some forms of genomic testing. However, there is significant variability, particularly regarding testing as part of clinical service. Some countries have a well-delineated rare disease pathway and have a national plan for rare diseases combined or not with a national plan for genomics in medicine. In other countries, there is a well-established organization of genetic centres that offer reimbursed genomic testing of RED and other rare diseases. Clinicians often rely upon research-funded laboratories or private companies. Notably, some member states rely on cross-border testing by way of an academic research project. Consequently, many clinicians are either unable to access testing or are confronted with long turnaround times. Overall, while the cost of sequencing has dropped, the cumulative cost of a genomic testing service for populations remains considerable. Importantly, the majority of countries reported healthcare budgets that limit testing. Short conclusion Despite technological advances, critical gaps in genomic testing remain in Europe, especially in smaller countries where no formal genomic testing pathways exist. Even within larger countries, the existing arrangements are insufficient to meet the demand and to ensure access. ERN-EYE promotes access to genetic testing in RED and emphasizes the clinical need and relevance of genetic testing in RED.
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83
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Georgiou M, Fujinami K, Michaelides M. Inherited retinal diseases: Therapeutics, clinical trials and end points-A review. Clin Exp Ophthalmol 2021; 49:270-288. [PMID: 33686777 DOI: 10.1111/ceo.13917] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Revised: 02/22/2021] [Accepted: 03/01/2021] [Indexed: 12/18/2022]
Abstract
Inherited retinal diseases (IRDs) are a clinically and genetically heterogeneous group of disorders characterised by photoreceptor degeneration or dysfunction. These disorders typically present with severe vision loss that can be progressive, with disease onset ranging from congenital to late adulthood. The advances in genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRDs, with the first approved gene therapy and the commencement of multiple clinical trials. The scope of this review is to familiarise clinicians and scientists with the current management and the prospects for novel therapies for: (1) macular dystrophies, (2) cone and cone-rod dystrophies, (3) cone dysfunction syndromes, (4) Leber congenital amaurosis, (5) rod-cone dystrophies, (6) rod dysfunction syndromes and (7) chorioretinal dystrophies. We also briefly summarise the investigated end points for the ongoing trials.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Kaoru Fujinami
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan.,Department of Ophthalmology, Keio University School of Medicine, Tokyo, Japan
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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84
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Transient electroretinographic abnormalities that mimic those of KCNV2 retinopathy: a case report. Doc Ophthalmol 2021; 143:221-228. [PMID: 33738644 PMCID: PMC8494656 DOI: 10.1007/s10633-021-09828-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 02/24/2021] [Indexed: 11/30/2022]
Abstract
Purpose The purpose of this report was to describe the case of a 68-year-old male patient with stage IV colon cancer who exhibited electroretinographic abnormalities that are similar to those of KCNV2 retinopathy. Methods The patient presenting with photophobia, reduced visual acuity, and poor general conditions, the onset of which occurred ten days before presentation, was examined using fundoscopy, full-field electroretinography, blood tests, and abdominal computed tomography. Results The patient’s decimal best-corrected visual acuity (BCVA) was 0.4 in each eye. Fundoscopy showed bull's eye-like maculopathy in both eyes. Electroretinographic findings were similar to the characteristic findings of KCNV2 retinopathy: Rod electroretinogram showed delayed and preserved b-wave amplitudes; bright-flash electroretinogram showed double troughs of a-waves; b/a ratios shown by bright-flash electroretinogram were higher than those shown by standard-flash electroretinogram; and both cone and 30-Hz flicker electroretinograms showed extinguished responses. His serum potassium level increased to 6.2 mmol/L (normal range 3.6–4.8 mmol/L) owing to hydronephrosis resulting from disseminated carcinoma. After performing an emergency surgery to treat this condition, the serum potassium level immediately decreased to a normal range. Eleven days after presentation, rod and standard/bright-flash electroretinography showed improvement in the implicit time of the rod b-waves and the a-waves. Unexpectedly, the responses recorded by cone and 30-Hz flicker electroretinography became normal. The symptoms and maculopathy disappeared, and his BCVA improved to 1.2. Conclusions The abnormal electroretinographic findings might be associated with the transient increase in serum potassium level.
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Aleman TS, O'Neil EC, O'Connor K, Jiang YY, Aleman IA, Bennett J, Morgan JIW, Toussaint BW. Bardet-Biedl syndrome-7 ( BBS7) shows treatment potential and a cone-rod dystrophy phenotype that recapitulates the non-human primate model. Ophthalmic Genet 2021; 42:252-265. [PMID: 33729075 DOI: 10.1080/13816810.2021.1888132] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Purpose: To provide a detailed ophthalmic phenotype of two male patients with Bardet-Biedl Syndrome (BBS) due to mutations in the BBS7 geneMethods: Two brothers ages 26 (Patient 1, P1) and 23 (P2) underwent comprehensive ophthalmic evaluations over three years. Visual function was assessed with full-field electroretinograms (ffERGs), kinetic and chromatic perimetry, multimodal imaging with spectral domain optical coherence tomography (SD-OCT), fundus autofluorescence (FAF) with short- (SW) and near-infrared (NIR) excitation lights and adaptive optics scanning light ophthalmoscopy (AOSLO).Results: Both siblings had a history of obesity and postaxial polydactyly; P2 had diagnoses of type 1 Diabetes Mellitus, Addison's disease, high-functioning autism-spectrum disorder and -12D myopia. Visual acuities were better than 20/30. Kinetic fields were moderately constricted. Cone-mediated ffERGs were undetectable, rod ERGs were ~80% of normal mean. Static perimetry showed severe central cone and rod dysfunction. Foveal to parafoveal hypoautofluorescence, most obvious on NIR-FAF, co-localized with outer segment shortening/loss and outer nuclear layer thinning by SD-OCT, and with reduced photoreceptors densities by AOSLO. A structural-functional dissociation was confirmed for cone- and rod-mediated parameters. Worsening of the above abnormalities was documented by SD-OCT and FAF in P2 at 3 years. Gene screening identified compound heterozygous mutations in BBS7 (p.Val266Glu: c.797 T > A of maternal origin; c.1781_1783delCAT, paternal) in both patients.Conclusions: BBS7-associated retinal degeneration may present as a progressive cone-rod dystrophy pattern, reminiscent of both the murine and non-human primate models of the disease. Predominantly central retinal abnormalities in both cone and rod photoreceptors showed a structural-functional dissociation, an ideal scenario for gene augmentation treatments.
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Affiliation(s)
- Tomas S Aleman
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Ophthalmology of the Children's Hospital of Philadelphia, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Erin C O'Neil
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Division of Ophthalmology of the Children's Hospital of Philadelphia, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Keli O'Connor
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Yu You Jiang
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Isabella A Aleman
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jean Bennett
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Jessica I W Morgan
- Scheie Eye Institute at the Perelman Center for Advanced Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Center for Advanced Retinal and Ocular Therapeutics, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Brian W Toussaint
- Christiana Care Health System, Wilmington, Delaware, USA.,Department of Ophthalmology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, USA
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86
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Georgiou M, Ali N, Yang E, Grewal PS, Rotsos T, Pontikos N, Robson AG, Michaelides M. Extending the phenotypic spectrum of PRPF8, PRPH2, RP1 and RPGR, and the genotypic spectrum of early-onset severe retinal dystrophy. Orphanet J Rare Dis 2021; 16:128. [PMID: 33712029 PMCID: PMC7953775 DOI: 10.1186/s13023-021-01759-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 02/25/2021] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To present the detailed retinal phenotype of patients with Leber Congenital Amaurosis/Early-Onset Severe Retinal Dystrophy (LCA/EOSRD) caused by sequence variants in four genes, either not (n = 1) or very rarely (n = 3) previously associated with the disease. METHODS Retrospective case series of LCA/EOSRD from four pedigrees. Chart review of clinical notes, multimodal retinal imaging, electrophysiology, and molecular genetic testing at a single tertiary referral center (Moorfields Eye Hospital, London, UK). RESULTS The mean age of presentation was 3 months of age, with disease onset in the first year of life in all cases. Molecular genetic testing revealed the following disease-causing variants: PRPF8 (heterozygous c.5804G > A), PRPH2 (homozygous c.620_627delinsTA, novel variant), RP1 (homozygous c.4147_4151delGGATT, novel variant) and RPGR (heterozygous c.1894_1897delGACA). PRPF8, PRPH2, and RP1 variants have very rarely been reported, either as unique cases or case reports, with limited clinical data presented. RPGR variants have not previously been associated with LCA/EOSRD. Clinical history and detailed retinal imaging are presented. CONCLUSIONS The reported cases extend the phenotypic spectrum of PRPF8-, PRPH2-, RP1-, and RPGR-associated disease, and the genotypic spectrum of LCA/EOSRD. The study highlights the importance of retinal and functional phenotyping, and the importance of specific genetic diagnosis to potential future therapy.
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital, London, UK
| | | | | | | | - Tryfon Rotsos
- First Division of Ophthalmology, General Hospital of Athens, National and Kapodistrian University of Athens, Athens, Greece
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK
- Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
- Moorfields Eye Hospital, London, UK.
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87
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Coco-Martin RM, Diego-Alonso M, Orduz-Montaña WA, Sanabria MR, Sanchez-Tocino H. Descriptive Study of a Cohort of 488 Patients with Inherited Retinal Dystrophies. Clin Ophthalmol 2021; 15:1075-1084. [PMID: 33727790 PMCID: PMC7955737 DOI: 10.2147/opth.s293381] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Accepted: 02/04/2021] [Indexed: 11/23/2022] Open
Abstract
Purpose To analyze the distribution of inherited retinal diseases (IRDs), describe the clinical characteristics of patients, and determine the percentages of patients with genetic diagnosis in the Castilla y Leon region of Spain. Methods All patients with an IRD seen in the two major referral units of Castilla y Leon during a 20-year period were included. The ages at symptom onset, diagnosis, and the last visit; sex; family history; history of consanguinity; type of inheritance; status of the fundus and electroretinogram findings; lens and macular status, visual acuity; and visual field data were recorded. Patients were divided into those with retinitis pigmentosa (RP) and all others. Gene mutations were gathered when available. Results Four hundred eighty-eight patients with IRDs were studied: 216 (44.26%) with RP of which 34 (15.74%) had syndromic diseases, and 272 had other conditions being 161 (59,19%) macular dystrophies. The mean delay in diagnosis was 6–16.2 years respectively. For the RP group the mean age at the last visit was 47.96±17,26; mean age of cataract surgery was 48.30 ± 12.01 years; and the foveal area was preserved in 74 (35.07%) patients, atrophic in 101 (47.87%), and edematous in 36 (17.06%). A genetic study had been performed in 58 (26.85%) of patients with RP and 71 (26,1%) of the rest, being indeterminate in 17 (29.31%) out of RP group and 20 (28.16%) out of the others. Conclusion Clinical characteristics are comparable to other published series. There is a significant delay in diagnosis. The number of patients with IRDs and available genetic diagnosis, thus being possible candidates for undergoing personalized treatments including gene therapy in our region is low and must be improved.
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Affiliation(s)
- Rosa M Coco-Martin
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), University of Valladolid, Valladolid, Spain.,Red Temática de Investigación Cooperativa en Salud de Oftalmologia (Oftared), Instituto de Salud Carlos III, Madrid, Spain
| | - Miguel Diego-Alonso
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), University of Valladolid, Valladolid, Spain.,Department of Ophthalmology, Hospital Universitario Río Hortega, Valladolid, Spain
| | - W Andres Orduz-Montaña
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), University of Valladolid, Valladolid, Spain
| | - M Rosa Sanabria
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), University of Valladolid, Valladolid, Spain.,Department of Ophthalmology, Complejo Hospitalario De Palencia, Palencia, Spain
| | - Hortensia Sanchez-Tocino
- Instituto Universitario de Oftalmobiología Aplicada (IOBA), University of Valladolid, Valladolid, Spain.,Department of Ophthalmology, Hospital Universitario Río Hortega, Valladolid, Spain
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88
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Sánchez-Bellver L, Toulis V, Marfany G. On the Wrong Track: Alterations of Ciliary Transport in Inherited Retinal Dystrophies. Front Cell Dev Biol 2021; 9:623734. [PMID: 33748110 PMCID: PMC7973215 DOI: 10.3389/fcell.2021.623734] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 02/09/2021] [Indexed: 01/14/2023] Open
Abstract
Ciliopathies are a group of heterogeneous inherited disorders associated with dysfunction of the cilium, a ubiquitous microtubule-based organelle involved in a broad range of cellular functions. Most ciliopathies are syndromic, since several organs whose cells produce a cilium, such as the retina, cochlea or kidney, are affected by mutations in ciliary-related genes. In the retina, photoreceptor cells present a highly specialized neurosensory cilium, the outer segment, stacked with membranous disks where photoreception and phototransduction occurs. The daily renewal of the more distal disks is a unique characteristic of photoreceptor outer segments, resulting in an elevated protein demand. All components necessary for outer segment formation, maintenance and function have to be transported from the photoreceptor inner segment, where synthesis occurs, to the cilium. Therefore, efficient transport of selected proteins is critical for photoreceptor ciliogenesis and function, and any alteration in either cargo delivery to the cilium or intraciliary trafficking compromises photoreceptor survival and leads to retinal degeneration. To date, mutations in more than 100 ciliary genes have been associated with retinal dystrophies, accounting for almost 25% of these inherited rare diseases. Interestingly, not all mutations in ciliary genes that cause retinal degeneration are also involved in pleiotropic pathologies in other ciliated organs. Depending on the mutation, the same gene can cause syndromic or non-syndromic retinopathies, thus emphasizing the highly refined specialization of the photoreceptor neurosensory cilia, and raising the possibility of photoreceptor-specific molecular mechanisms underlying common ciliary functions such as ciliary transport. In this review, we will focus on ciliary transport in photoreceptor cells and discuss the molecular complexity underpinning retinal ciliopathies, with a special emphasis on ciliary genes that, when mutated, cause either syndromic or non-syndromic retinal ciliopathies.
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Affiliation(s)
- Laura Sánchez-Bellver
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
| | - Vasileios Toulis
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
| | - Gemma Marfany
- Departament de Genètica, Microbiologia i Estadística, Universitat de Barcelona, Barcelona, Spain
- Institute of Biomedicine (IBUB-IRSJD), Universitat de Barcelona, Barcelona, Spain
- CIBERER, ISCIII, Universitat de Barcelona, Barcelona, Spain
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89
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Muftuoglu IK, Al-Sheikh M, J S, Rasheed MA, Singh SR, Chhablani J. Imaging in inherited retinal disorders. Eur J Ophthalmol 2021; 31:1656-1676. [PMID: 33525895 DOI: 10.1177/1120672121990578] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Inherited retinal diseases, which results from mutations in over 260 identified genes, affect more than 2 million people globally. The diseases mostly cause severe vision loss in young working population and have severe impact on social economic status of the population. Advances in retinal imaging techniques along with developments in gene identification and cell biology techniques have yielded to a better understanding of the genetic and biochemical mechanisms causing these diseases. Retinal imaging along with through ophthalmological examination is essential to make an accurate diagnosis, to decrease the burden of unneccessary anciliary tests and to select the potential patients that can get benefit from the gene treatment. The purpose of the review is to yield an update on inherited retinal diseases by highlighting microstructural changes in retina and to summarize the retinal changes detected by currently available multimodal imaging techniques.
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Affiliation(s)
- Ilkay Kilic Muftuoglu
- Department of Ophthalmology, Istanbul Training and Research Hospital, Istanbul, Turkey
| | - Mayss Al-Sheikh
- Department of Ophthalmology, University Hospital Zurich, University of Zurich, Zurich, Switzerland
| | - Sushma J
- LV Prasad Eye Institute, Hyderabad, Telangana, India
| | | | - Sumit Randhir Singh
- Jacobs Retina Center at Shiley Eye Center, University of California, San Diego, La Jolla, CA, USA
| | - Jay Chhablani
- UPMC Eye Center, University of Pittsburgh, Pittsburgh, PA, USA
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90
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Lorenz B, Tavares J, van den Born LI, Marques JP, Scholl HPN. Current Management of Inherited Retinal Degeneration Patients in Europe: Results of a Multinational Survey by the European Vision Institute Clinical Research Network. Ophthalmic Res 2021; 64:622-638. [PMID: 33465765 DOI: 10.1159/000514540] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/15/2021] [Indexed: 11/19/2022]
Abstract
PURPOSE An increasing number of gene therapies are developed for Inherited Retinal Degenerations (IRD). To date, 1 treatment has been approved for clinical use (FDA USA 2017, EMA Europe 2018, MoHAP UAE 2019, SFDA Saudi Arabia 2019, Swiss Medic Switzerland 2020, TGA Australia 2020, and BFR Brazil 2020). While such therapies do not provide complete cure, they may halt degeneration or partially restore function. Identification of well-characterized patients is an emerging need. We conducted the first multinational survey to understand the management of IRDs in Europe. METHODS An electronic survey questionnaire containing 112 questions was developed and sent to the 101 EVICR.net clinical centers (14 European countries and Israel). RESULTS The overall response rate was 49%. Only 14% of responding centers do not see IRD patients; 52% that manage IRD patients follow ≥200 patients, 16% > 1,000. Databases exist in 86% of the centers; of these, 75% are local files, 28% local Web-based database, and 19% national Web-based. IRD patients are referred to EVICR.net centers mainly by general ophthalmologists, patient self-referrals, and medical retina specialists. Most IRD patients are first seen in adulthood. Most prominent signs and symptoms depend on the age of onset, for example, nystagmus in infancy, or night blindness, and reduced visual acuity at older age. The time from inquiring for first appointment and clinical diagnosis varies among countries: in 29% of centers, the mean time is <4 weeks, although can be up to 35 months in others. The time to genetic diagnosis is ≥4 weeks, the maximum 10 years, likely depending on access to genetic testing, and the improvement of the tests available. Comprehensive eye examination always includes autofluorescence imaging and perimetry (86% static, 76% kinetic, and 21% microperimetry), and frequently optical coherence tomography (OCT) (95%), electroretinography (93%), and fundus photography (93%). Identified genotypes were reported in 40-80% patients by 69% of centers, and in 80-100% by 5%. Genetic testing is provided by public health insurance in 77% of centers, private health insurance in 38%, center budget in 13%, research funds in 18%; and 15% of centers do not have access to genetic testing. CONCLUSION At the start of this era of ocular gene therapy for IRD patients, this first international survey on management of IRDs in Europe highlights significant heterogeneity between centers and across countries and provides important baseline data for researchers, clinicians, pharmaceutical companies, and investors.
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Affiliation(s)
- Birgit Lorenz
- Department of Ophthalmology, Justus-Liebig-University Giessen, Giessen, Germany.,Department of Ophthalmology, University Hospital Bonn, Bonn, Germany
| | - Joana Tavares
- Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal
| | | | - João P Marques
- Center for Clinical Trials, Association for Innovation and Biomedical Research on Light and Image (AIBILI), Coimbra, Portugal.,Department of Ophthalmology, Centro Hospitalar e Universitário de Coimbra (CHUC), Coimbra, Portugal.,Faculty of Medicine, University of Coimbra (FMUC), Coimbra, Portugal
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland.,Department of Ophthalmology, University of Basel, Basel, Switzerland.,Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA
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91
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Garafalo AV, Sheplock R, Sumaroka A, Roman AJ, Cideciyan AV, Jacobson SG. Childhood-onset genetic cone-rod photoreceptor diseases and underlying pathobiology. EBioMedicine 2021; 63:103200. [PMID: 33421946 PMCID: PMC7806809 DOI: 10.1016/j.ebiom.2020.103200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/01/2020] [Accepted: 12/17/2020] [Indexed: 12/27/2022] Open
Abstract
Inherited retinal diseases (IRDs) were first classified clinically by history, ophthalmoscopic appearance, type of visual field defects, and electroretinography (ERG). ERGs isolating the two major photoreceptor types (rods and cones) showed some IRDs with greater cone than rod retinal dysfunction; others were the opposite. Within the cone-rod diseases, there can be phenotypic variability, which can be attributed to genetic heterogeneity and the variety of visual function mechanisms that are disrupted. Most cause symptoms from childhood or adolescence, although others can manifest later in life. Among the causative genes for cone-rod dystrophy (CORD) are those encoding molecules in phototransduction cascade activation and recovery processes, photoreceptor outer segment structure, the visual cycle and photoreceptor development. We review 11 genes known to cause cone-rod disease in the context of their roles in normal visual function and retinal structure. Knowledge of the pathobiology of these genetic diseases is beginning to pave paths to therapy.
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Affiliation(s)
- Alexandra V Garafalo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Alejandro J Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Artur V Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Samuel G Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.
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92
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Costello F, Chen JJ. The role of optical coherence tomography in the diagnosis of afferent visual pathway problems: A neuroophthalmic perspective. HANDBOOK OF CLINICAL NEUROLOGY 2021; 178:97-113. [PMID: 33832689 DOI: 10.1016/b978-0-12-821377-3.00007-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Optical coherence tomography (OCT) is a noninvasive ocular imaging technique that has become a standard tool in neuroophthalmic practice. Specifically, OCT captures retinal manifestations of neuroaxonal injury caused by lesions along anterior and posterior regions of the afferent visual pathway, in patients presenting with vision loss. More recently, the advent of OCT angiography (OCTA) has enabled evaluation of the choroidal and retinal microvasculature, thus informing our understanding regarding vascular mechanisms associated with optic nerve and retinal injuries. Much of our longitudinal experience with OCT in the field of neuroophthalmology has been acquired from the study of optic neuritis (ON) caused by inflammatory disorders of the central nervous system (CNS). Over the past two decades, OCT has emerged as a surrogate endpoint for CNS neuroaxonal injury in multiple sclerosis (MS) research trials. On a more pragmatic level, OCT is used in the clinical arena to diagnose ON associated with: MS, neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein (MOG) antibody associated disease (MOGAD). Subsequent advancements in swept-source (SS) and enhanced depth imaging (EDI) have established OCT as the new "gold standard" in the diagnosis of optic disc drusen. Recent studies have highlighted pathognomonic OCT features that distinguish cases of true papilledema from pseudopapilledema, in patients presenting with undifferentiated optic disc elevation. Preoperative OCT measures of neuroaxonal integrity have shown prognostic value in predicting postoperative visual outcomes for patients with compressive anterior visual pathway lesions. Finally, OCT is indispensable in differentiating optic neuropathies from retinal diseases in patients with visual loss and a nondiagnostic fundus examination. An in-depth discussion regarding the technical aspects of OCT is beyond the scope of this chapter. Instead, we wish to highlight the value OCT brings to the diagnosis and management of common neuroophthalmic conditions, with emphasis on optic neuropathies and retinal disorders.
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Affiliation(s)
- Fiona Costello
- Departments of Clinical Neurosciences and Surgery, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
| | - John J Chen
- Departments of Ophthalmology and Neurology, Mayo Clinic, Rochester, MN, United States
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93
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Expanding the Clinical and Genetic Spectrum of RAB28-Related Cone-Rod Dystrophy: Pathogenicity of Novel Variants in Italian Families. Int J Mol Sci 2020; 22:ijms22010381. [PMID: 33396523 PMCID: PMC7795990 DOI: 10.3390/ijms22010381] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 12/28/2020] [Accepted: 12/28/2020] [Indexed: 12/11/2022] Open
Abstract
The small Ras-related GTPase Rab-28 is highly expressed in photoreceptor cells, where it possibly participates in membrane trafficking. To date, six alterations in the RAB28 gene have been associated with autosomal recessive cone-rod dystrophies. Confirmed variants include splicing variants, missense and nonsense mutations. Here, we present a thorough phenotypical and genotypical characterization of five individuals belonging to four Italian families, constituting the largest cohort of RAB28 patients reported in literature to date. All probands displayed similar clinical phenotype consisting of photophobia, decreased visual acuity, central outer retinal thinning, and impaired color vision. By sequencing the four probands, we identified: a novel homozygous splicing variant; two novel nonsense variants in homozygosis; a novel missense variant in compound heterozygous state with a previously reported nonsense variant. Exhaustive molecular dynamics simulations of the missense variant p.(Thr26Asn) in both its active and inactive states revealed an allosteric structural mechanism that impairs the binding of Mg2+, thus decreasing the affinity for GTP. The impaired GTP-GDP exchange ultimately locks Rab-28 in a GDP-bound inactive state. The loss-of-function mutation p.(Thr26Asn) was present in a compound heterozygosis with the nonsense variant p.(Arg137*), which does not cause mRNA-mediated decay, but is rather likely degraded due to its incomplete folding. The frameshift p.(Thr26Valfs4*) and nonsense p.(Leu13*) and p.(Trp107*) variants, if translated, would lack several key structural components necessary for the correct functioning of the encoded protein.
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94
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Piedade WP, Titialii-Torres K, Morris AC, Famulski JK. Proteasome-Mediated Regulation of Cdhr1a by Siah1 Modulates Photoreceptor Development and Survival in Zebrafish. Front Cell Dev Biol 2020; 8:594290. [PMID: 33330480 PMCID: PMC7719784 DOI: 10.3389/fcell.2020.594290] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 10/22/2020] [Indexed: 01/05/2023] Open
Abstract
Congenital retinal dystrophies are a major cause of unpreventable and incurable blindness worldwide. Mutations in CDHR1, a retina specific cadherin, are associated with cone-rod dystrophy. The ubiquitin proteasome system (UPS) is responsible for mediating orderly and precise targeting of protein degradation to maintain biological homeostasis and coordinate proper development, including retinal development. Recently, our lab uncovered that the seven in absentia (Siah) family of E3 ubiquitin ligases play a role in optic fissure fusion and identified Cdhr1a as a potential target of Siah. Using two-color whole mount in situ hybridization and immunohistochemistry, we detected siah1 and cdhr1a co-expression as well as protein localization in the retinal outer nuclear layer (ONL), and more precisely in the connecting cilium of rods and cones between 3-5 days post fertilization (dpf). We confirmed that Siah1 targets Cdhr1a for proteasomal degradation by co-transfection and co-immunoprecipitation in cell culture. To analyze the functional importance of this interaction, we created two transgenic zebrafish lines that express siah1 or an inactive siah1 (siah1ΔRING) under the control of the heat shock promoter to modulate Siah activity during photoreceptor development. Overexpression of siah1, but not siah1ΔRING, resulted in a decrease in the number of rods and cones at 72 h post fertilization (hpf). The number of retinal ganglion cells, amacrine and bipolar cells was not affected by Siah1 overexpression, and there was no significant reduction of proliferating cells in the Siah1 overexpressing retina. We did, however, detect increased cell death, confirmed by an increase in the number of TUNEL + cells in the ONL, which was proteasome-dependent, as proteasome inhibition rescued the cell death phenotype. Furthermore, reduction in rods and cones resulting from increased Siah1 expression was rescued by injection of cdhr1a mRNA, and to an even greater extent by injection of a Siah1-insensitive cdhr1a variant mRNA. Lastly, CRISPR induced loss of Cdhr1a function phenocopied Siah1 overexpression resulting in a significant reduction of rods and cones. Taken together, our work provides the first evidence that Cdhr1a plays a role during early photoreceptor development and that Cdhr1a is regulated by Siah1 via the UPS.
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Affiliation(s)
| | | | | | - Jakub K. Famulski
- Department of Biology, University of Kentucky, Lexington, KY, United States
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95
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Loss of Class III Phosphoinositide 3-Kinase Vps34 Results in Cone Degeneration. BIOLOGY 2020; 9:biology9110384. [PMID: 33171845 PMCID: PMC7695136 DOI: 10.3390/biology9110384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/26/2020] [Accepted: 11/04/2020] [Indexed: 12/15/2022]
Abstract
The major pathway for the production of the low-abundance membrane lipid phosphatidylinositol 3-phosphate (PI(3)P) synthesis is catalyzed by class III phosphoinositide 3-kinase (PI3K) Vps34. The absence of Vps34 was previously found to disrupt autophagy and other membrane-trafficking pathways in some sensory neurons, but the roles of phosphatidylinositol 3-phosphate and Vps34 in cone photoreceptor cells have not previously been explored. We found that the deletion of Vps34 in neighboring rods in mouse retina did not disrupt cone function up to 8 weeks after birth, despite diminished rod function. Immunoblotting and lipid analysis of cones isolated from the cone-dominant retinas of the neural retina leucine zipper gene knockout mice revealed that both PI(3)P and Vps34 protein are present in mouse cones. To determine whether Vps34 and PI(3)P are important for cone function, we conditionally deleted Vps34 in cone photoreceptor cells of the mouse retina. Overall retinal morphology and rod function appeared to be unaffected. However, the loss of Vps34 in cones resulted in the loss of structure and function. There was a substantial reduction throughout the retina in the number of cones staining for M-opsin, S-opsin, cone arrestin, and peanut agglutinin, revealing degeneration of cones. These studies indicate that class III PI3K, and presumably PI(3)P, play essential roles in cone photoreceptor cell function and survival.
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96
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Tang L, Liu M, Hu C, Zhou B, Lam PKS, Lam JCW, Chen L. Binary exposure to hypoxia and perfluorobutane sulfonate disturbs sensory perception and chromatin topography in marine medaka embryos. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2020; 266:115284. [PMID: 32781212 DOI: 10.1016/j.envpol.2020.115284] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/23/2020] [Accepted: 07/26/2020] [Indexed: 06/11/2023]
Abstract
Perfluorobutane sulfonate (PFBS), an environmental pollutant of emerging concern, is previously shown to dynamically interact with hypoxia on aquatic developmental toxicities. However, the molecular mechanisms underlying the interaction remain unknown. In this follow-up study, marine medaka embryos were exposed to 0 and 3.3 mg/L of PFBS under normoxia (6.9 mg/L) or hypoxia (1.7 mg/L) condition till 15 days post-fertilization. High-throughput transcriptomic sequencing was employed to filter differentially expressed genes and provide mechanistic insight into interactive action between hypoxia and PFBS. The results showed that hypoxia alone and the coexposure paradigm were similarly potent to modify transcriptional profiles, with the majority of genes significantly down-regulated. In contrast, transcriptional toxicity of PFBS was relatively milder. Functional annotation analyses found that hypoxia and coexposure groups mainly impacted phototransduction signaling by decreasing the transcriptions of cyclic nucleotide-gated (CNG) cation channels and retinol transport genes. However, this study demonstrated the first toxicological evidence that toxic effects of PFBS targeted the perception of chemical stimulus through olfactory and gustatory receptors. The addition of PFBS moderately exacerbated the toxic actions of hypoxia, which largely shaped the transcriptional pattern of coexposure group. In addition, gene interactive networks were constructed for hypoxia and coexposure groups, underlining the increased chromatin deacetylation and methylation to epigenetically repress genome-wide transcriptional initiation. Overall, PFBS and hypoxia interact to interrupt the embryonic development of sensory systems, which may compromise the individual fitness and survival, especially during early life stages when precocious perception of food and escape from predators are essential.
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Affiliation(s)
- Lizhu Tang
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Mengyuan Liu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Chenyan Hu
- School of Chemistry and Environmental Engineering, Wuhan Institute of Technology, Wuhan, 430072, China
| | - Bingsheng Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Paul K S Lam
- State Key Laboratory of Marine Pollution and Department of Chemistry, City University of Hong Kong, Kowloon, SAR, Hong Kong, China
| | - James C W Lam
- Department of Science and Environmental Studies, The Education University of Hong Kong, SAR, Hong Kong, China
| | - Lianguo Chen
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
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97
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Ran J, Zhou J. Targeting the photoreceptor cilium for the treatment of retinal diseases. Acta Pharmacol Sin 2020; 41:1410-1415. [PMID: 32753732 DOI: 10.1038/s41401-020-0486-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 06/28/2020] [Indexed: 02/08/2023] Open
Abstract
Photoreceptors, as polarised sensory neurons, are essential for light sensation and phototransduction, which are highly dependent on the photoreceptor cilium. Structural defects and/or dysfunction of the photoreceptor cilium caused by mutations in photoreceptor-specific genes or common ciliary genes can lead to retinal diseases, including syndromic and nonsyndromic diseases. In this review, we describe the structure and function of the photoreceptor cilium. We also discuss recent findings that underscore the dysregulation of the photoreceptor cilium in various retinal diseases and the therapeutic potential of targeting ciliary genes in these diseases.
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98
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Ceramide synthase TLCD3B is a novel gene associated with human recessive retinal dystrophy. Genet Med 2020; 23:488-497. [PMID: 33077892 PMCID: PMC7936949 DOI: 10.1038/s41436-020-01003-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 09/29/2020] [Accepted: 09/30/2020] [Indexed: 11/30/2022] Open
Abstract
Purpose Previous studies suggest that ceramide is a proapoptotic lipid as high levels of ceramides can lead to apoptosis of neuronal cells, including photoreceptors. However, no pathogenic variant in ceramide synthases has been identified in human patients and knockout of various ceramide synthases in mice has not led to photoreceptor degeneration. Methods Exome sequencing was used to identify candidate disease genes in patients with vision loss as confirmed by standard evaluation methods, including electroretinography (ERG) and optical coherence tomography. The vision loss phenotype in mice was evaluated by ERG and histological analyses. Results Here we have identified four patients with cone-rod dystrophy or maculopathy from three families carrying pathogenic variants in TLCD3B. Consistent with the phenotype observed in patients, the Tlcd3bKO/KO mice exhibited a significant reduction of the cone photoreceptor light responses, thinning of the outer nuclear layer, and loss of cone photoreceptors across the retina. Conclusion Our results provide the first link between loss-of-function variants in a ceramide synthase gene and human retinal dystrophy. Establishment of the Tlcd3b knockout murine model, the first in vivo photoreceptor cell degeneration model due to loss of a ceramide synthase, will provide a unique opportunity in probing the role of ceramide in survival and function of photoreceptor cells.
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99
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Abstract
Inherited retinal diseases (IRD) are a leading cause of blindness in the working age population. The advances in ocular genetics, retinal imaging and molecular biology, have conspired to create the ideal environment for establishing treatments for IRD, with the first approved gene therapy and the commencement of multiple therapy trials. The scope of this review is to familiarize clinicians and scientists with the current landscape of retinal imaging in IRD. Herein we present in a comprehensive and concise manner the imaging findings of: (I) macular dystrophies (MD) [Stargardt disease (ABCA4), X-linked retinoschisis (RS1), Best disease (BEST1), pattern dystrophy (PRPH2), Sorsby fundus dystrophy (TIMP3), and autosomal dominant drusen (EFEMP1)], (II) cone and cone-rod dystrophies (GUCA1A, PRPH2, ABCA4 and RPGR), (III) cone dysfunction syndromes [achromatopsia (CNGA3, CNGB3, PDE6C, PDE6H, GNAT2, ATF6], blue-cone monochromatism (OPN1LW/OPN1MW array), oligocone trichromacy, bradyopsia (RGS9/R9AP) and Bornholm eye disease (OPN1LW/OPN1MW), (IV) Leber congenital amaurosis (GUCY2D, CEP290, CRB1, RDH12, RPE65, TULP1, AIPL1 and NMNAT1), (V) rod-cone dystrophies [retinitis pigmentosa, enhanced S-Cone syndrome (NR2E3), Bietti crystalline corneoretinal dystrophy (CYP4V2)], (VI) rod dysfunction syndromes (congenital stationary night blindness, fundus albipunctatus (RDH5), Oguchi disease (SAG, GRK1), and (VII) chorioretinal dystrophies [choroideremia (CHM), gyrate atrophy (OAT)].
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Affiliation(s)
- Michalis Georgiou
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Kaoru Fujinami
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK.,Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, National Hospital Organization Tokyo Medical Center, Tokyo, Japan
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK.,Moorfields Eye Hospital NHS Foundation Trust, London, UK
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100
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De Silva SR, Arno G, Robson AG, Fakin A, Pontikos N, Mohamed MD, Bird AC, Moore AT, Michaelides M, Webster AR, Mahroo OA. The X-linked retinopathies: Physiological insights, pathogenic mechanisms, phenotypic features and novel therapies. Prog Retin Eye Res 2020; 82:100898. [PMID: 32860923 DOI: 10.1016/j.preteyeres.2020.100898] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 08/07/2020] [Accepted: 08/21/2020] [Indexed: 02/08/2023]
Abstract
X-linked retinopathies represent a significant proportion of monogenic retinal disease. They include progressive and stationary conditions, with and without syndromic features. Many are X-linked recessive, but several exhibit a phenotype in female carriers, which can help establish diagnosis and yield insights into disease mechanisms. The presence of affected carriers can misleadingly suggest autosomal dominant inheritance. Some disorders (such as RPGR-associated retinopathy) show diverse phenotypes from variants in the same gene and also highlight limitations of current genetic sequencing methods. X-linked disease frequently arises from loss of function, implying potential for benefit from gene replacement strategies. We review X-inactivation and X-linked inheritance, and explore burden of disease attributable to X-linked genes in our clinically and genetically characterised retinal disease cohort, finding correlation between gene transcript length and numbers of families. We list relevant genes and discuss key clinical features, disease mechanisms, carrier phenotypes and novel experimental therapies. We consider in detail the following: RPGR (associated with retinitis pigmentosa, cone and cone-rod dystrophy), RP2 (retinitis pigmentosa), CHM (choroideremia), RS1 (X-linked retinoschisis), NYX (complete congenital stationary night blindness (CSNB)), CACNA1F (incomplete CSNB), OPN1LW/OPN1MW (blue cone monochromacy, Bornholm eye disease, cone dystrophy), GPR143 (ocular albinism), COL4A5 (Alport syndrome), and NDP (Norrie disease and X-linked familial exudative vitreoretinopathy (FEVR)). We use a recently published transcriptome analysis to explore expression by cell-type and discuss insights from electrophysiology. In the final section, we present an algorithm for genes to consider in diagnosing males with non-syndromic X-linked retinopathy, summarise current experimental therapeutic approaches, and consider questions for future research.
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Affiliation(s)
- Samantha R De Silva
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Gavin Arno
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony G Robson
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Ana Fakin
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Nikolas Pontikos
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Moin D Mohamed
- Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK
| | - Alan C Bird
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA, USA
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Omar A Mahroo
- UCL Institute of Ophthalmology, University College London, UK; Moorfields Eye Hospital NHS Foundation Trust, London, UK; Department of Ophthalmology, Guy's & St Thomas' NHS Foundation Trust, London, UK; Section of Ophthalmology, King's College London, UK; Physiology, Development and Neuroscience, University of Cambridge, Cambridge, UK.
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