1
|
Danish E, Alhashem A, Aljehani R, Aljawi A, Aldarwish MM, Al Mutairi F, Alfadhel M, Alrifai MT, Alobaisi S. Phenotype and genotype of 15 Saudi patients with achromatopsia: A case series. Saudi J Ophthalmol 2023; 37:301-306. [PMID: 38155673 PMCID: PMC10752271 DOI: 10.4103/sjopt.sjopt_108_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 07/23/2023] [Accepted: 07/27/2023] [Indexed: 12/30/2023] Open
Abstract
PURPOSE Achromatopsia is a rare stationary retinal disorder that primarily affects the cone photoreceptors. Individuals with achromatopsia present with photophobia, nystagmus, reduced visual acuity (VA), and color blindness. Multiple genes responsible for achromatopsia have been identified (e.g. cyclic nucleotide-gated channel subunit alpha 3 [CNGA3] and activating transcription factor 6). Studies have assessed the role of gene therapy in achromatopsia. Therefore, for treatment and prevention, the identification of phenotypes and genotypes is crucial. Here, we described the clinical manifestations and genetic mutations associated with achromatopsia in patients from Saudi Arabia. METHODS This case series study included 15 patients with clinical presentations, suggestive of achromatopsia, who underwent ophthalmological and systemic evaluations. Patients with typical achromatopsia phenotype underwent genetic evaluation using whole-exome testing. RESULTS All patients had nystagmus (n = 15) and 93.3% had photophobia (n = 14). In addition, all patients (n = 15) had poor VA. Hyperopia with astigmatism was observed in 93.3% (n = 14) and complete color blindness in 93.3% of the patients (n = 14). In the context of family history, both parents of all patients (n = 15) were genetic carriers, with a high consanguinity rate (82%, n = 9 families). Electroretinography showed cone dysfunction with normal rods in 66.7% (n = 10) and both cone-rod dysfunction in 33.3% (n = 5) patients. Regarding the genotypic features, 93% of patients had variants in CNGA3 (n = 14) categorized as pathogenic Class 1 (86.7%, n = 13). Further, 66.7% (n = 10) of patients also harbored the c.661C>T DNA variant. Further, the patients were homozygous for these mutations. Three other variants were also identified: c.1768G>A (13.3%, n = 2), c.830G>A (6.6%, n = 1), and c. 822G >T (6.6%, n = 1). CONCLUSION Consanguinity and belonging to the same tribe are major risk factors for disease inheritance. The most common genotype was CNGA3 with the c.661C>T DNA variant. We recommend raising awareness among families and providing genetic counseling for this highly debilitating disease.
Collapse
Affiliation(s)
- Enam Danish
- Department of Ophthalmology, King Fahad Armed Forces Hospital, Jeddah, Saudi Arabia
| | - Amal Alhashem
- Department of Pediatric, Division of Genetic and Metabolic Medicine, Prince Sultan Medical Military City, College of Medicine, Alfaisal University, Riyadh, Saudi Arabia
| | - Reham Aljehani
- Department of Ophthalmology, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Anan Aljawi
- Department of Ophthalmology, King Abdulaziz Medical City, Jeddah, Saudi Arabia
| | - Manar M. Aldarwish
- Department of Genetics and Precision Medicine, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Fuad Al Mutairi
- Department of Genetics and Precision Medicine, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- King Abdullah International Medical Research Centre, Ministry of National Guard Health Affairs, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Majid Alfadhel
- Department of Genetics and Precision Medicine, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
- Department of Medical Genomics Research, King Abdullah International Medical Research Center, Ministry of National Guard Health Affairs, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
| | - Muhammad T. Alrifai
- King Abdullah International Medical Research Centre, Ministry of National Guard Health Affairs, King Saud Bin Abdulaziz University for Health Sciences, Riyadh, Saudi Arabia
- Pediatric Ophthalmology Division, Department of Pediatric Surgery, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| | - Saif Alobaisi
- Pediatric Ophthalmology Division, Department of Pediatric Surgery, King Abdullah Specialized Children Hospital, King Abdulaziz Medical City, Ministry of National Guard Health Affairs, Riyadh, Saudi Arabia
| |
Collapse
|
2
|
Molz B, Herbik A, Baseler HA, de Best PB, Vernon RW, Raz N, Gouws AD, Ahmadi K, Lowndes R, McLean RJ, Gottlob I, Kohl S, Choritz L, Maguire J, Kanowski M, Käsmann-Kellner B, Wieland I, Banin E, Levin N, Hoffmann MB, Morland AB. Structural changes to primary visual cortex in the congenital absence of cone input in achromatopsia. Neuroimage Clin 2022; 33:102925. [PMID: 34959047 PMCID: PMC8718719 DOI: 10.1016/j.nicl.2021.102925] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/30/2022]
Abstract
Anatomy of primary visual cortex (V1) assessed with surface-based morphmetry in those with congenital achromatopsia (ACHM). Reduction in cortical surface area in foveal, parafoveal and paracentral representations of V1 in those with ACHM. In ACHM a localized thickening in the area of V1 that represents the region of retina occupied solely by cones. V1 changes in ACHM may limit its ability to take on normal properties if retinal function were to be restored. Early intervention, before the development plastic period is over, may offer better restoration of vision in ACHM.
Autosomal recessive Achromatopsia (ACHM) is a rare inherited disorder associated with dysfunctional cone photoreceptors resulting in a congenital absence of cone input to visual cortex. This might lead to distinct changes in cortical architecture with a negative impact on the success of gene augmentation therapies. To investigate the status of the visual cortex in these patients, we performed a multi-centre study focusing on the cortical structure of regions that normally receive predominantly cone input. Using high-resolution T1-weighted MRI scans and surface-based morphometry, we compared cortical thickness, surface area and grey matter volume in foveal, parafoveal and paracentral representations of primary visual cortex in 15 individuals with ACHM and 42 normally sighted, healthy controls (HC). In ACHM, surface area was reduced in all tested representations, while thickening of the cortex was found highly localized to the most central representation. These results were comparable to more widespread changes in brain structure reported in congenitally blind individuals, suggesting similar developmental processes, i.e., irrespective of the underlying cause and extent of vision loss. The cortical differences we report here could limit the success of treatment of ACHM in adulthood. Interventions earlier in life when cortical structure is not different from normal would likely offer better visual outcomes for those with ACHM.
Collapse
Affiliation(s)
- Barbara Molz
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom; Language and Genetics Department, Max Planck Institute for Psycholinguistics, 6525 XD Nijmegen, Netherlands
| | - Anne Herbik
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Heidi A Baseler
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom; Hull York Medical School, University of York, Heslington, YO10 5DD York, United Kingdom; York Biomedical Research Institute, University of York, Heslington, YO10 5DD York, United Kingdom
| | - Pieter B de Best
- MRI Unit, Department of Neurology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Richard W Vernon
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom
| | - Noa Raz
- MRI Unit, Department of Neurology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Andre D Gouws
- York Neuroimaging Centre, Department of Psychology, University of York, YO10 5NY York, United Kingdom
| | - Khazar Ahmadi
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Rebecca Lowndes
- York Neuroimaging Centre, Department of Psychology, University of York, YO10 5NY York, United Kingdom
| | - Rebecca J McLean
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, LE2 7LX Leicester, United Kingdom
| | - Irene Gottlob
- University of Leicester Ulverscroft Eye Unit, University of Leicester, Leicester Royal Infirmary, LE2 7LX Leicester, United Kingdom
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University Clinics Tübingen, 72076 Tübingen, Germany
| | - Lars Choritz
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - John Maguire
- School of Optometry and Vision Sciences, University of Bradford, BD7 1DP Bradford, United Kingdom
| | - Martin Kanowski
- Department of Neurology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Barbara Käsmann-Kellner
- Department of Ophthalmology, Saarland University Hospital and Medical Faculty of the Saarland University, 66421 Homburg, Germany
| | - Ilse Wieland
- Department for Molecular Genetics, Institute for Human Genetics, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Eyal Banin
- Degenerative Diseases of the Retina Unit, Department of Ophthalmology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Netta Levin
- MRI Unit, Department of Neurology, Hadassah Medical Center, 91120 Jerusalem, Israel
| | - Michael B Hoffmann
- Department of Ophthalmology, University Hospital, Otto-von-Guericke University, 39120 Magdeburg, Germany; Center for Behavioral Brain Sciences, 39106 Magdeburg, Germany
| | - Antony B Morland
- Department of Psychology, University of York, Heslington, YO10 5DD York, United Kingdom; York Biomedical Research Institute, University of York, Heslington, YO10 5DD York, United Kingdom; York Neuroimaging Centre, Department of Psychology, University of York, YO10 5NY York, United Kingdom.
| |
Collapse
|
3
|
Righetti G, Kempf M, Braun C, Jung R, Kohl S, Wissinger B, Zrenner E, Stingl K, Stingl K. Oscillatory Potentials in Achromatopsia as a Tool for Understanding Cone Retinal Functions. Int J Mol Sci 2021; 22:12717. [PMID: 34884517 PMCID: PMC8657736 DOI: 10.3390/ijms222312717] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/19/2021] [Accepted: 11/22/2021] [Indexed: 11/25/2022] Open
Abstract
Achromatopsia (ACHM) is an inherited autosomal recessive disease lacking cone photoreceptors functions. In this study, we characterize the time-frequency representation of the full-field electroretinogram (ffERG) component oscillatory potentials (OPs), to investigate the connections between photoreceptors and the inner retinal network using ACHM as a model. Time-frequency characterization of OPs was extracted from 52 controls and 41 achromat individuals. The stimulation via ffERG was delivered under dark-adaptation (DA, 3.0 and 10.0 cd·s·m-2) to assess mixed rod-cone responses. The ffERG signal was subsequently analyzed using a continuous complex Morlet transform. Time-frequency maps of both DA conditions show the characterization of OPs, disclosing in both groups two distinct time-frequency windows (~70-100 Hz and >100 Hz) within 50 ms. Our main result indicates a significant cluster (p < 0.05) in both conditions of reduced relative power (dB) in ACHM people compared to controls, mainly at the time-frequency window >100 Hz. These results suggest that the strongly reduced but not absent activity of OPs above 100 Hz is mostly driven by cones and only in small part by rods. Thus, the lack of cone modulation of OPs gives important insights into interactions between photoreceptors and the inner retinal network and can be used as a biomarker for monitoring cone connection to the inner retina.
Collapse
Affiliation(s)
- Giulia Righetti
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany; (M.K.); (R.J.); (K.S.); (K.S.)
| | - Melanie Kempf
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany; (M.K.); (R.J.); (K.S.); (K.S.)
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tübingen, Germany;
| | - Christoph Braun
- MEG-Center, University of Tübingen, 72076 Tübingen, Germany;
- CIMeC, Center for Mind/Brain Science, University of Trento, 38123 Trento, Italy
| | - Ronja Jung
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany; (M.K.); (R.J.); (K.S.); (K.S.)
| | - Susanne Kohl
- Molecular Genetics Laboratory, Center for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; (S.K.); (B.W.)
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Center for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany; (S.K.); (B.W.)
| | - Eberhart Zrenner
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tübingen, Germany;
- Center for Ophthalmology, Institute for Ophthalmic Research, University of Tübingen, 72076 Tübingen, Germany
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, 72076 Tübingen, Germany
| | - Katarina Stingl
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany; (M.K.); (R.J.); (K.S.); (K.S.)
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tübingen, Germany;
| | - Krunoslav Stingl
- Center for Ophthalmology, University Eye Hospital, University of Tübingen, 72076 Tübingen, Germany; (M.K.); (R.J.); (K.S.); (K.S.)
- Center for Rare Eye Diseases, University of Tübingen, 72076 Tübingen, Germany;
| |
Collapse
|
4
|
Tekavčič Pompe M, Vrabič N, Volk M, Meglič A, Jarc-Vidmar M, Peterlin B, Hawlina M, Fakin A. Disease Progression in CNGA3 and CNGB3 Retinopathy; Characteristics of Slovenian Cohort and Proposed OCT Staging Based on Pooled Data from 126 Patients from 7 Studies. Curr Issues Mol Biol 2021; 43:941-957. [PMID: 34449556 PMCID: PMC8929018 DOI: 10.3390/cimb43020067] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/02/2021] [Accepted: 08/05/2021] [Indexed: 11/20/2022] Open
Abstract
Achromatopsia has been proposed to be a morphologically predominately stable retinopathy with rare reports of progression of structural changes in the macula. A five-grade system of optical coherence tomography (OCT) features has been used for the classification of structural macular changes. However, their association with age remains questionable. We characterized the Slovenian cohort of 12 patients with pathogenic variants in CNGA3 or CNGB3 who had been followed up with OCT for up to 9 years. Based on observed structural changes in association with age, the following four-stage classification of retinal morphological changes was proposed: (I) preserved inner segment ellipsoid band (Ise), (II) disrupted ISe, (III) ISe loss and (IV) ISe and RPE loss. Data from six previously published studies reporting OCT morphology in CNGA3 and CNGB3 patients were additionally collected, forming the largest CNGA3/CNGB3 cohort to date, comprising 126 patients aged 1–71 years. Multiple regression analysis showed a significant correlation of OCT stage with age (p < 0.001) and no correlation with gene (p > 0.05). The median ages of patients with stages I–IV were 12 years, 23 years, 27 years and 48 years, respectively, and no patient older than 50 years had continuous ISe. Our findings suggest that achromatopsia presents with slowly but steadily progressive structural changes of the macular outer retinal layers. However, whether morphological changes in time follow the proposed four-stage linear pattern needs to be confirmed in a long-term study.
Collapse
Affiliation(s)
- Manca Tekavčič Pompe
- Eye Hospital, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.T.P.); (N.V.); (A.M.); (M.J.-V.); (M.H.)
| | - Nika Vrabič
- Eye Hospital, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.T.P.); (N.V.); (A.M.); (M.J.-V.); (M.H.)
| | - Marija Volk
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.V.); (B.P.)
| | - Andrej Meglič
- Eye Hospital, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.T.P.); (N.V.); (A.M.); (M.J.-V.); (M.H.)
| | - Martina Jarc-Vidmar
- Eye Hospital, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.T.P.); (N.V.); (A.M.); (M.J.-V.); (M.H.)
| | - Borut Peterlin
- Clinical Institute of Genomic Medicine, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.V.); (B.P.)
| | - Marko Hawlina
- Eye Hospital, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.T.P.); (N.V.); (A.M.); (M.J.-V.); (M.H.)
| | - Ana Fakin
- Eye Hospital, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (M.T.P.); (N.V.); (A.M.); (M.J.-V.); (M.H.)
- Correspondence:
| |
Collapse
|
5
|
Suppiej A, Ceccato C, Maritan V, Cermakova I, Colavito D, Leon A. Exome sequencing and electro-clinical features in pediatric patients with very early-onset retinal dystrophies: A cohort study. Eur J Paediatr Neurol 2021; 31:1-9. [PMID: 33529788 DOI: 10.1016/j.ejpn.2021.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 01/01/2021] [Accepted: 01/10/2021] [Indexed: 12/31/2022]
Abstract
BACKGROUND AND OBJECTIVE Inherited retinal dystrophies (IRDs) are a major cause of childhood blindness. Timely diagnosis requires a high level of clinical suspicion from both neurologists and ophthalmologists and is increasingly important given recent advancements in gene therapy. We focused our study on genotype-phenotype associations in very early-onset forms of retinal dystrophy, the least well characterized and most challenging diagnostic subgroup. METHODS From January 12, 2015 to March 31, 2017, we prospectively performed whole exome sequencing targeted on the phenotype of non-syndromic IRDs and phenotype characterization in a cohort of 68 children affected by very early-onset inherited retinal dystrophies, defined by the onset before five years of age. Phenotype parameters included age at onset, clinical presentation, ophthalmic evaluation, electrophysiological patterns and clinical course. RESULTS A genetically confirmed diagnosis was achieved in 50 out of 60 (83%) families. The median age at onset was 4 months (<6 m in 70%, < 2 y in 82% of the cases). Clinical presentation was associated with visual loss and nystagmus in the majority of patients. Three (CNGB3, CNGA3 and CACNA1F) out of 22 genes considered pathogenic in the cohort, accounted for 51% of all IRD's, all within the class of stationary IRDs. CONCLUSIONS This study reports on the largest cohort of very early-onset retinal dystrophies, including a description of electroretinography patterns. The electro-clinical phenotype coupled with genetic diagnosis provided additional clues for child neurologists dealing with low vision and nystagmus in infancy. A high level of clinical suspicion improves the diagnosis with important implications for the future of the affected child.
Collapse
Affiliation(s)
- A Suppiej
- Department of Medical Sciences, Paediatric Section, University of Ferrara, Italy; Paediatric University Hospital of Padova- Neuro-ophthalmology Program, Italy; Robert Hollman Foundation, Padova, Italy.
| | - C Ceccato
- Robert Hollman Foundation, Padova, Italy
| | - V Maritan
- Paediatric University Hospital of Padova- Neuro-ophthalmology Program, Italy; Ophthalmology Unit, Azienda ULSS 6 Euganea, Padova, Italy
| | | | - D Colavito
- Research & Innovation (R&I Genetics), Padova, Italy
| | - A Leon
- Research & Innovation (R&I Genetics), Padova, Italy
| |
Collapse
|
6
|
El Moussawi Z, Boueiri M, Al-Haddad C. Gene therapy in color vision deficiency: a review. Int Ophthalmol 2021; 41:1917-1927. [PMID: 33528822 DOI: 10.1007/s10792-021-01717-0] [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: 10/16/2020] [Accepted: 01/09/2021] [Indexed: 11/24/2022]
Abstract
BACKGROUND Color vision deficiencies are a group of vision disorders, characterized by abnormal color discrimination. They include red-green color blindness, yellow-blue color blindness and achromatopsia, among others. The deficiencies are caused by mutations in the genes coding for various components of retinal cones. Gene therapy is rising as a promising therapeutic modality. The purpose of this review article is to explore the available literature on gene therapy in the different forms of color vision deficiencies. METHODS A thorough literature review was performed on PubMed using the keywords: color vision deficiencies, gene therapy, achromatopsia and the various genes responsible for this condition (OPN1LW, OPN1MW, ATF6, CNGA3, CNGB3, GNAT2, PDE6H, and PDE6C). RESULTS Various adenovirus vectors have been deployed to test the efficacy of gene therapy for achromatopsia in animals and humans. Gene therapy trials in humans and animals targeting mutations in CNGA3 have been performed, demonstrating an improvement in electroretinogram (ERG)-investigated cone cell functionality. Similar outcomes have been reported for experimental studies on other genes (CNGB3, GNAT2, M- and L-opsin). It has also been reported that delivering the genes via intravitreal rather than subretinal injections could be safer. There are currently 3 ongoing human clinical trials for the treatment of achromatopsia due to mutations in CNGB3 and CNGA3. CONCLUSION Experimental studies and clinical trials generally showed improvement in ERG-investigated cone cell functionality and visually elicited behavior. Gene therapy is a promising novel therapeutic modality in color vision deficiencies.
Collapse
Affiliation(s)
- Zeinab El Moussawi
- Ophthalmology Department, American University of Beirut, Beirut, Lebanon
| | - Marguerita Boueiri
- Faculty of Medicine, Medical School, American University of Beirut, Beirut, Lebanon
| | | |
Collapse
|
7
|
Moshiri A, Chen R, Kim S, Harris RA, Li Y, Raveendran M, Davis S, Liang Q, Pomerantz O, Wang J, Garzel L, Cameron A, Yiu G, Stout JT, Huang Y, Murphy CJ, Roberts J, Gopalakrishna KN, Boyd K, Artemyev NO, Rogers J, Thomasy SM. A nonhuman primate model of inherited retinal disease. J Clin Invest 2019; 129:863-874. [PMID: 30667376 PMCID: PMC6355306 DOI: 10.1172/jci123980] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 11/15/2018] [Indexed: 12/30/2022] Open
Abstract
Inherited retinal degenerations are a common cause of untreatable blindness worldwide, with retinitis pigmentosa and cone dystrophy affecting approximately 1 in 3500 and 1 in 10,000 individuals, respectively. A major limitation to the development of effective therapies is the lack of availability of animal models that fully replicate the human condition. Particularly for cone disorders, rodent, canine, and feline models with no true macula have substantive limitations. By contrast, the cone-rich macula of a nonhuman primate (NHP) closely mirrors that of the human retina. Consequently, well-defined NHP models of heritable retinal diseases, particularly cone disorders that are predictive of human conditions, are necessary to more efficiently advance new therapies for patients. We have identified 4 related NHPs at the California National Primate Research Center with visual impairment and findings from clinical ophthalmic examination, advanced retinal imaging, and electrophysiology consistent with achromatopsia. Genetic sequencing confirmed a homozygous R565Q missense mutation in the catalytic domain of PDE6C, a cone-specific phototransduction enzyme associated with achromatopsia in humans. Biochemical studies demonstrate that the mutant mRNA is translated into a stable protein that displays normal cellular localization but is unable to hydrolyze cyclic GMP (cGMP). This NHP model of a cone disorder will not only serve as a therapeutic testing ground for achromatopsia gene replacement, but also for optimization of gene editing in the macula and of cone cell replacement in general.
Collapse
Affiliation(s)
- Ala Moshiri
- Department of Ophthalmology & Vision Science, School of Medicine, UC Davis, Sacramento, California, USA
| | - Rui Chen
- Human Genome Sequencing Center and Department of Molecular and Human Genetics, and.,Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Soohyun Kim
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| | - R Alan Harris
- Human Genome Sequencing Center and Department of Molecular and Human Genetics, and
| | - Yumei Li
- Human Genome Sequencing Center and Department of Molecular and Human Genetics, and
| | | | - Sarah Davis
- California National Primate Research Center, Davis, California, USA
| | - Qingnan Liang
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Ori Pomerantz
- California National Primate Research Center, Davis, California, USA
| | - Jun Wang
- Human Genome Sequencing Center and Department of Molecular and Human Genetics, and
| | - Laura Garzel
- California National Primate Research Center, Davis, California, USA
| | - Ashley Cameron
- California National Primate Research Center, Davis, California, USA
| | - Glenn Yiu
- Department of Ophthalmology & Vision Science, School of Medicine, UC Davis, Sacramento, California, USA
| | - J Timothy Stout
- Department of Ophthalmology, Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA
| | | | - Christopher J Murphy
- Department of Ophthalmology & Vision Science, School of Medicine, UC Davis, Sacramento, California, USA.,Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.,EyeKor Inc., Madison, Wisconsin, USA
| | - Jeffrey Roberts
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA.,California National Primate Research Center, Davis, California, USA
| | | | - Kimberly Boyd
- Department of Molecular Physiology and Biophysics, and
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, and.,Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, Iowa, USA
| | - Jeffrey Rogers
- Human Genome Sequencing Center and Department of Molecular and Human Genetics, and
| | - Sara M Thomasy
- Department of Ophthalmology & Vision Science, School of Medicine, UC Davis, Sacramento, California, USA.,Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California-Davis, Davis, California, USA
| |
Collapse
|
8
|
Hlavatá L, Ďuďáková Ľ, Moravíková J, Zobanová A, Kousal B, Lišková P. Molecular genetic cause of achromatopsia in two patients of Czech origin. CESKA A SLOVENSKA OFTALMOLOGIE : CASOPIS CESKE OFTALMOLOGICKE SPOLECNOSTI A SLOVENSKE OFTALMOLOGICKE SPOLECNOSTI 2019; 75:272-276. [PMID: 32397729 DOI: 10.31348/2019/5/5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
INTRODUCTION Achromatopsia is an autosomal recessive retinal disorder with an estimated prevalence ranging from 1 in 30.000 to 50.000. The disease is caused by mutations in six different genes. The aim of the study was to perform molecular genetic analysis in 11 unrelated probands with a clinical diagnosis of achromatopsia and to describe clinical findings in those that were found to carry biallelic pathogenic mutations. METHODS All probands and their parents underwent ophthalmic examination. Mutation detection was performed using Sanger sequencing of CNGB3 exons 6, 7, 9-13, which have been found to harbour most disease-causing mutations in patients with achromatopsia of European origin. RESULTS Three known pathogenic variants in CNGB3 were identified in 2 probands. Proband 1 was a compound heterozygote for the c.819_826del; p.(Arg274Valfs*13) and c.1006G>T; p.(Glu336*). Proband 2 carried the c.1148del; p.(Thr383Ilefs*13) in a homozygous state. The best corrected visual acuity in proband 1 (aged 19 years) was 0.1 in both eyes, in proband 2 (aged 8 years) 0.05 in the right eye and 0.1 in the left eye. Both individuals had nystagmus, photophobia, and absence of colour discrimination. Fundus examination appeared normal however spectral-domain optical coherence tomography revealed subtle bilaterally symmetrical structural changes in the fovea. CONCLUSION Molecular genetic analysis of Czech patients with achromatopsia was performed for the first time. Identification of disease-causing mutations in achromatopsia is important for establishing an early diagnosis, participation in clinical trials assessing gene therapies and may be also used for preimplantation genetic diagnosis.
Collapse
|
9
|
Pascual-Camps I, Barranco-Gonzalez H, Aviñó-Martínez J, Silva E, Harto-Castaño M. Diagnosis and Treatment Options for Achromatopsia: A Review of the Literature. J Pediatr Ophthalmol Strabismus 2018; 55:85-92. [PMID: 29257187 DOI: 10.3928/01913913-20171117-01] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/28/2017] [Indexed: 01/31/2023]
Abstract
Achromatopsia is a complex inherited retinal disease that affects the cone cell function. It is usually an autosomal-recessive disease and is characterized by pendular nystagmus, poor visual acuity, lack of color vision, and marked photophobia. CNGA3, CNGB3, GNAT2, PDE6C, PDE6H, and ATF6 gene mutations have been identified as associated with this disease. New diagnostic and therapeutic tools are being studied. Optical coherence tomography and fundus autofluorescence are important imaging techniques that provide significant information about the progression of the disease. The genetic approach for these patients is a current important issue and gene therapy is an ongoing therapeutic option already being studied in clinical trials. The purpose of this review was to survey the current knowledge on diagnosis and treatment options in achromatopsia. [J Pediatr Ophthalmol Strabismus. 2018;55(2):85-92.].
Collapse
|
10
|
Hirji N, Aboshiha J, Georgiou M, Bainbridge J, Michaelides M. Achromatopsia: clinical features, molecular genetics, animal models and therapeutic options. Ophthalmic Genet 2018; 39:149-157. [PMID: 29303385 DOI: 10.1080/13816810.2017.1418389] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Achromatopsia is an autosomal recessive condition, characterised by reduced visual acuity, impaired colour vision, photophobia and nystagmus. The symptoms can be profoundly disabling, and there is no cure currently available. However, the recent development of gene-based interventions may lead to improved outcomes in the future. This article aims to provide a comprehensive review of the clinical features of the condition, its genetic basis and the underlying pathogenesis. We also explore the insights derived from animal models, including the implications for gene supplementation approaches. Finally, we discuss current human gene therapy trials.
Collapse
Affiliation(s)
- Nashila Hirji
- a UCL Institute of Ophthalmology, University College London , London , UK.,b Moorfields Eye Hospital , London , UK
| | - Jonathan Aboshiha
- a UCL Institute of Ophthalmology, University College London , London , UK.,b Moorfields Eye Hospital , London , UK
| | - Michalis Georgiou
- a UCL Institute of Ophthalmology, University College London , London , UK.,b Moorfields Eye Hospital , London , UK
| | - James Bainbridge
- a UCL Institute of Ophthalmology, University College London , London , UK.,b Moorfields Eye Hospital , London , UK
| | - Michel Michaelides
- a UCL Institute of Ophthalmology, University College London , London , UK.,b Moorfields Eye Hospital , London , UK
| |
Collapse
|
11
|
|
12
|
Ling Y, Xu L, Zhu L, Sui M, Zheng Q, Li W, Liu Y, Fang F, Zhang X. Identification and analysis of differentially expressed long non-coding RNAs between multiparous and uniparous goat (Capra hircus) ovaries. PLoS One 2017; 12:e0183163. [PMID: 28934224 PMCID: PMC5608193 DOI: 10.1371/journal.pone.0183163] [Citation(s) in RCA: 21] [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: 01/06/2017] [Accepted: 07/31/2017] [Indexed: 12/02/2022] Open
Abstract
Long non-coding RNAs (lncRNAs) play important roles in almost all biological processes. However, there is little information on the effects of lncRNAs on ovulation and lambing rates. In the present study, we used high-throughput RNA sequencing to identify differentially expressed lncRNAs between the ovaries of multiparous (Mul) and uniparous (Uni) Anhui White goats. Among the 107,255,422 clean reads, 183,754 lncRNAs were significantly differentially expressed between the Uni and Mul. Among them, 455 lncRNAs were co-expressed between the two samples, whereas, 157,523 lncRNAs were uniquely expressed in the Uni, and 25,776 uniquely lncRNAs were expressed in the Mul. Through Cis role analysis, 24 lncRNAs were predicted to overlap with cis-regulatory elements, which involved in Progesterone-mediated oocyte maturation, Steroid biosynthesis, Oocyte meiosis, and gonadotropin-releasing hormone (GnRH) signaling pathway. These 4 pathways were related to ovulation, and the KEGG pathway analysis on target genes of the differentially expressed lncRNAs confirmed this results. In addition, 10 lncRNAs harbored precursors of 40 miRNAs, such as TCONS_00320849 related to a mature miRNA sequence, miR-365a, which was reported to be related to proliferation, were annotated in the precursor analysis of miRNAs. The present expand the understanding of lncRNA biology and contribute to the annotation of the goat genome. The study will provide a resource for lncRNA studies of ovulation and lambing.
Collapse
Affiliation(s)
- Yinghui Ling
- College of Animal Science and Technology, Anhui Agricultural University, Anhui Hefei, China
- Local Animal Genetic Resources Conservation and Biobreeding Laboratory of Anhui Province, Anhui Hefei, China
| | - Lina Xu
- Institute of Plant Protection and Agro-Products Safety, Anhui Academy of Agricultural Sciences, Hefei, Anhui, China
| | - Long Zhu
- College of Animal Science and Technology, Anhui Agricultural University, Anhui Hefei, China
- Local Animal Genetic Resources Conservation and Biobreeding Laboratory of Anhui Province, Anhui Hefei, China
| | - Menghua Sui
- College of Animal Science and Technology, Anhui Agricultural University, Anhui Hefei, China
- Local Animal Genetic Resources Conservation and Biobreeding Laboratory of Anhui Province, Anhui Hefei, China
| | - Qi Zheng
- College of Animal Science and Technology, Anhui Agricultural University, Anhui Hefei, China
- Local Animal Genetic Resources Conservation and Biobreeding Laboratory of Anhui Province, Anhui Hefei, China
| | - Wenyong Li
- Key Laboratory of Embryo Development and Reproductive Regulation of Anhui Province, Fuyang Normal University, Fuyang, Anhui, China
| | - Yong Liu
- Key Laboratory of Embryo Development and Reproductive Regulation of Anhui Province, Fuyang Normal University, Fuyang, Anhui, China
| | - Fugui Fang
- College of Animal Science and Technology, Anhui Agricultural University, Anhui Hefei, China
- Local Animal Genetic Resources Conservation and Biobreeding Laboratory of Anhui Province, Anhui Hefei, China
- * E-mail: (ZXR); (FFG)
| | - Xiaorong Zhang
- College of Animal Science and Technology, Anhui Agricultural University, Anhui Hefei, China
- Local Animal Genetic Resources Conservation and Biobreeding Laboratory of Anhui Province, Anhui Hefei, China
- * E-mail: (ZXR); (FFG)
| |
Collapse
|
13
|
Maguire J, McKibbin M, Khan K, Kohl S, Ali M, McKeefry D. CNGB3 mutations cause severe rod dysfunction. Ophthalmic Genet 2017; 39:108-114. [PMID: 28929832 DOI: 10.1080/13816810.2017.1368087] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE Congenital achromatopsia or rod monochromatism is a rare autosomal recessive condition defined by a severe loss of cone photoreceptor function in which rods purportedly retain normal or near-to-normal function. This report describes the results of electroretinography in two siblings with CNGB3-associated achromatopsia. METHODS Full field light- and dark-adapted electroretinograms (ERGs) were recorded using standard protocols detailed by the International Society for Clinical Electrophysiology of Vision (ISCEV). We also examined rod-mediated ERGs using series of stimuli that varied over a 6 log unit range of retinal illuminances (-1.9-3.5 log scotopic trolands). RESULTS Dark-adapted ERGs in achromatopsia patients exhibited severely reduced b-wave amplitudes with abnormal b:a ratios (1.3 and 0.6). In comparison, the reduction in a-wave amplitude was less marked. The rod-mediated ERG took on an electronegative appearance at high-stimulus illuminances. CONCLUSION Although the defect that causes achromatopsia is primarily in the cone photoreceptors, our results reveal an accompanying disruption of rod function that is more severe than has previously been reported. The differential effects on the b-wave relative to the a-wave points to an inner-retinal locus for the disruption of rod function in these patients.
Collapse
Affiliation(s)
- J Maguire
- a School of Optometry and Vision Sciences , University of Bradford , Bradford , West Yorkshire , UK
| | - M McKibbin
- b Department of Ophthalmology , St. James's University Teaching Hospital , Leeds , UK
| | - K Khan
- b Department of Ophthalmology , St. James's University Teaching Hospital , Leeds , UK
| | - S Kohl
- c Molecular Genetics Laboratory, Institute of Ophthalmic Research, Centre of Ophthalmology , University Clinics Tubingen , Tubingen , Germany
| | - M Ali
- d Section of Ophthalmology and Neuroscience, Leeds Institute of Biomedical and Clinical Sciences , University of Leeds , Leeds , UK
| | - D McKeefry
- a School of Optometry and Vision Sciences , University of Bradford , Bradford , West Yorkshire , UK
| |
Collapse
|
14
|
Campi I, Cammarata G, Bianchi Marzoli S, Beck-Peccoz P, Santarsiero D, Dazzi D, Bottari de Castello A, Taroni EG, Viola F, Mian C, Watutantrige-Fernando S, Pelusi C, Muzza M, Maffini MA, Persani L. Retinal Photoreceptor Functions Are Compromised in Patients With Resistance to Thyroid Hormone Syndrome (RTHβ). J Clin Endocrinol Metab 2017; 102:2620-2627. [PMID: 28379567 DOI: 10.1210/jc.2016-3671] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 03/27/2017] [Indexed: 01/29/2023]
Abstract
CONTEXT In animal models, disruption of thyroid hormone (TH) receptor-β (TRβ) reduces the long/medium wavelength (L/M) and increases the short-wavelength (S) cones. Retinal photoreceptor (RP) functions are unknown in patients with resistance to TH syndrome (RTHβ) with dominant-negative TRβ mutations. OBJECTIVE To investigate RP functions in RTHβ. DESIGN, SETTING, AND PARTICIPANTS Case-control study involving 27 RTHβ patients and 31 age/sex-matched controls, conducted in two tertiary referral centers in Italy. MAIN OUTCOME MEASURES Color vision sensitivity assessed by Farnsworth; central macular thickness (CMT) of the outer retinal layer measured by spectral-domain optical coherence tomography; and retinal function tested by full-field electroretinogram (ERG) and S-cone ERG. RESULTS Color sensitivity was worse in RTHβ patients than controls (P = 0.002). CMT was overlapping between the study groups but directly correlated with sex hormone-binding globuline levels in RTHβ. We found a significant reduction in amplitude of the cone (P = 0.024) and of the rod response (P = 0.006) in the ERG of RTHβ patients compared with controls. The response of the L/M cones measured by a specialized ERG test was lower in RTHβ than controls (P = 0.027), whereas no differences were found in the S-cone response. No correlations were found between TH levels, total error score, or electrophysiological results. Furthermore, no differences were found between patients with maternal or de novo/paternal inheritance. CONCLUSIONS We report, to our knowledge, the first in vivo evidence of functional defects of RP in RTHβ. These changes occur independently of endogenous TH levels or the prenatal exposure to high or normal maternal TH.
Collapse
Affiliation(s)
- Irene Campi
- Division of Endocrine and Metabolic Diseases, Laboratory of Endocrine and Metabolic Research, Istituto Di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, 20149 Milan, Italy
- Department of Pathophysiology and Transplantation, University of Milan, 20122 Milan, Italy
| | - Gabriella Cammarata
- Neuro-Ophthalmology Service, Electrophysiology Laboratory, Department of Ophthalmology, Istituto Di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, 20149 Milan, Italy
| | - Stefania Bianchi Marzoli
- Neuro-Ophthalmology Service, Electrophysiology Laboratory, Department of Ophthalmology, Istituto Di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, 20149 Milan, Italy
| | - Paolo Beck-Peccoz
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| | - Diletta Santarsiero
- Neuro-Ophthalmology Service, Electrophysiology Laboratory, Department of Ophthalmology, Istituto Di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, 20149 Milan, Italy
| | - Davide Dazzi
- Division of Internal Medicine, Ospedale Vaio, 43036 Fidenza, Parma, Italy
| | | | - Elena Giuliana Taroni
- Ophthalmology Unit, Fondazione Istituto Di Ricovero e Cura a Carattere Scientifico Ca' Granda, 20122 Milan, Italy
| | - Francesco Viola
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
- Ophthalmology Unit, Fondazione Istituto Di Ricovero e Cura a Carattere Scientifico Ca' Granda, 20122 Milan, Italy
| | - Caterina Mian
- Department of Medicine, Endocrinology Unit-University of Padua, 35128 Padova, Italy
| | | | - Carla Pelusi
- Department of Medical and Surgical Sciences, Division of Endocrinology, University of Bologna, Sant'Orsola-Malpighi Hospital, 40138 Bologna, Italy
| | - Marina Muzza
- Endocrine Unit, Fondazione Istituto Di Ricovero e Cura a Carattere Scientifico Ca' Granda, 20122 Milan, Italy
| | - Maria Antonia Maffini
- Endocrine Unit, Fondazione Istituto Di Ricovero e Cura a Carattere Scientifico Ca' Granda, 20122 Milan, Italy
| | - Luca Persani
- Division of Endocrine and Metabolic Diseases, Laboratory of Endocrine and Metabolic Research, Istituto Di Ricovero e Cura a Carattere Scientifico, Istituto Auxologico Italiano, 20149 Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, 20122 Milan, Italy
| |
Collapse
|
15
|
Maguire J, Parry NRA, Kremers J, Murray IJ, McKeefry D. The morphology of human rod ERGs obtained by silent substitution stimulation. Doc Ophthalmol 2017; 134:11-24. [PMID: 28091887 PMCID: PMC5274650 DOI: 10.1007/s10633-017-9571-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Accepted: 01/05/2017] [Indexed: 11/10/2022]
Abstract
Purpose To record transient ERGs from the light-adapted human retina using silent substitution stimuli which selectively reflect the activity of rod photoreceptors. We aim to describe the morphology of these waveforms and examine how they are affected by the use of less selective stimuli and by retinal pathology. Methods Rod-isolating stimuli with square-wave temporal profiles (250/250 ms onset/offset) were presented using a 4 primary LED ganzfeld stimulator. Experiment 1: ERGs were recorded using a rod-isolating stimulus (63 ph Td, rod contrast, Crod = 0.25) from a group (n = 20) of normal trichromatic observers. Experiment 2: Rod ERGs were recorded from a group (n = 5) using a rod-isolating stimulus (Crod = 0.25) which varied in retinal illuminance from 40 to 10,000 ph Td. Experiment 3: ERGs were elicited using 2 kinds of non-isolating stimuli; (1) broadband and (2) rod-isolating stimuli which contained varying degrees of L- and M-cone excitation. Experiment 4: Rod ERGs were recorded from two patient groups with rod monochromacy (n = 3) and CSNB (type 1; n = 2). Results The rod-isolated ERGs elicited from normal subjects had a waveform with a positive onset component followed by a negative offset. Response amplitude was maximal at retinal illuminances <100 ph Td and was virtually abolished at 400 ph Td. The use of non-selective stimuli altered the ERG waveform eliciting more photopic-like ERG responses. Rod ERGs recorded from rod monochromats had similar features to those recorded from normal trichromats, in contrast to those recorded from participants with CSNB which had an electronegative appearance. Conclusions Our results demonstrate that ERGs elicited by silent substitution stimuli can selectively reflect the operation of rod photoreceptors in the normal, light-adapted human retina.
Collapse
Affiliation(s)
- J Maguire
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK
| | - N R A Parry
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK.,Vision Science Centre, Manchester Royal Eye Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.,Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - J Kremers
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK.,Department of Ophthalmology, University Hospital Erlangen, Erlangen, Germany
| | - I J Murray
- Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - D McKeefry
- Bradford School of Optometry and Vision Sciences, University of Bradford, Bradford, W. Yorkshire, BD7 1DP, UK.
| |
Collapse
|
16
|
Aboshiha J, Dubis AM, Carroll J, Hardcastle AJ, Michaelides M. The cone dysfunction syndromes. Br J Ophthalmol 2016; 100:115-21. [PMID: 25770143 PMCID: PMC4717370 DOI: 10.1136/bjophthalmol-2014-306505] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 02/09/2015] [Indexed: 11/05/2022]
Abstract
The cone dysfunction syndromes are a heterogeneous group of inherited, predominantly stationary retinal disorders characterised by reduced central vision and varying degrees of colour vision abnormalities, nystagmus and photophobia. This review details the following conditions: complete and incomplete achromatopsia, blue-cone monochromatism, oligocone trichromacy, bradyopsia and Bornholm eye disease. We describe the clinical, psychophysical, electrophysiological and imaging findings that are characteristic to each condition in order to aid their accurate diagnosis, as well as highlight some classically held notions about these diseases that have come to be challenged over the recent years. The latest data regarding the genetic aetiology and pathological changes observed in the cone dysfunction syndromes are discussed, and, where relevant, translational avenues of research, including completed and anticipated interventional clinical trials, for some of the diseases described herein will be presented. Finally, we briefly review the current management of these disorders.
Collapse
Affiliation(s)
- Jonathan Aboshiha
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Adam M Dubis
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Joseph Carroll
- Department of Ophthalmology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Alison J Hardcastle
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital, London, UK
| |
Collapse
|
17
|
Zobor D, Zobor G, Kohl S. Achromatopsia: on the doorstep of a possible therapy. Ophthalmic Res 2015; 54:103-8. [PMID: 26304472 DOI: 10.1159/000435957] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 06/15/2015] [Indexed: 11/19/2022]
Abstract
Achromatopsia (ACHM) is a rare autosomal recessive inherited retinal disorder with an incidence of approximately 1 in 30,000. It presents at birth or early infancy and is typically characterized by reduced visual acuity, nystagmus, photophobia, and very poor or absent color vision. The symptoms arise from isolated cone dysfunction, which can be caused by mutations in the crucial components of the cone phototransduction cascade. Although ACHM is considered a functionally nonprogressive disease affecting only the cone system, recent studies have described progressive age-dependent changes in retinal architecture. Currently, no specific therapy is available for ACHM; however, gene replacement therapy performed on animal models for three ACHM genes has shown promising results. Accurate genetic and clinical diagnosis of patients may therefore enhance and enable therapeutic intervention in the near future. This short review summarizes the genetic background, pathophysiology, clinical findings, diagnostics, and therapeutic perspectives in ACHM.
Collapse
Affiliation(s)
- Ditta Zobor
- Institute for Ophthalmic Research, University of Tübingen, Tübingen, Germany
| | | | | |
Collapse
|
18
|
Luo X, Cideciyan AV, Iannaccone A, Roman AJ, Ditta LC, Jennings BJ, Yatsenko SA, Sheplock R, Sumaroka A, Swider M, Schwartz SB, Wissinger B, Kohl S, Jacobson SG. Blue cone monochromacy: visual function and efficacy outcome measures for clinical trials. PLoS One 2015; 10:e0125700. [PMID: 25909963 PMCID: PMC4409040 DOI: 10.1371/journal.pone.0125700] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Accepted: 03/21/2015] [Indexed: 12/22/2022] Open
Abstract
Background Blue Cone Monochromacy (BCM) is an X-linked retinopathy caused by mutations in the OPN1LW / OPN1MW gene cluster, encoding long (L)- and middle (M)-wavelength sensitive cone opsins. Recent evidence shows sufficient structural integrity of cone photoreceptors in BCM to warrant consideration of a gene therapy approach to the disease. In the present study, the vision in BCM is examined, specifically seeking clinically-feasible outcomes for a future clinical trial. Methods BCM patients (n = 25, ages 5–72) were studied with kinetic and static chromatic perimetry, full-field sensitivity testing, and eye movement recordings. Vision at the fovea and parafovea was probed with chromatic microperimetry. Results Kinetic fields with a Goldmann size V target were generally full. Short-wavelength (S-) sensitive cone function was normal or near normal in most patients. Light-adapted perimetry results on conventional background lights were abnormally reduced; 600-nm stimuli were seen by rods whereas white stimuli were seen by both rods and S-cones. Under dark-adapted conditions, 500-nm stimuli were seen by rods in both BCM and normals. Spectral sensitivity functions in the superior retina showed retained rod and S-cone functions in BCM under dark-adapted and light-adapted conditions. In the fovea, normal subjects showed L/M-cone mediation using a 650-nm stimulus under dark-adapted conditions, whereas BCM patients had reduced sensitivity driven by rod vision. Full-field red stimuli on bright blue backgrounds were seen by L/M-cones in normal subjects whereas BCM patients had abnormally reduced and rod-mediated sensitivities. Fixation location could vary from fovea to parafovea. Chromatic microperimetry demonstrated a large loss of sensitivity to red stimuli presented on a cyan adapting background at the anatomical fovea and surrounding parafovea. Conclusions BCM rods continue to signal vision under conditions normally associated with daylight vision. Localized and retina-wide outcome measures were examined to evaluate possible improvement of L/M-cone-based vision in a clinical trial.
Collapse
Affiliation(s)
- Xunda Luo
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Artur V. Cideciyan
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (SGJ); (AVC)
| | - Alessandro Iannaccone
- Hamilton Eye Institute, Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Alejandro J. Roman
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Lauren C. Ditta
- Hamilton Eye Institute, Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Barbara J. Jennings
- Hamilton Eye Institute, Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, Tennessee, United States of America
| | - Svetlana A. Yatsenko
- Pittsburgh Cytogenetics Laboratory, Center for Medical Genetics and Genomics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Rebecca Sheplock
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Alexander Sumaroka
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Malgorzata Swider
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Sharon B. Schwartz
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tuebingen, Tuebingen, Germany
| | - Samuel G. Jacobson
- Scheie Eye Institute, Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
- * E-mail: (SGJ); (AVC)
| |
Collapse
|
19
|
Zelinger L, Cideciyan AV, Kohl S, Schwartz SB, Rosenmann A, Eli D, Sumaroka A, Roman AJ, Luo X, Brown C, Rosin B, Blumenfeld A, Wissinger B, Jacobson SG, Banin E, Sharon D. Genetics and Disease Expression in the CNGA3 Form of Achromatopsia: Steps on the Path to Gene Therapy. Ophthalmology 2015; 122:997-1007. [PMID: 25616768 DOI: 10.1016/j.ophtha.2014.11.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Revised: 11/17/2014] [Accepted: 11/23/2014] [Indexed: 01/18/2023] Open
Abstract
PURPOSE Achromatopsia (ACHM) is a congenital, autosomal recessive retinal disease that manifests cone dysfunction, reduced visual acuity and color vision, nystagmus, and photoaversion. Five genes are known causes of ACHM. The present study took steps toward performing a trial of gene therapy in ACHM by characterizing the genetics of ACHM in Israel and the Palestinian Territories and analyzing retinal function and structure in CNGA3 ACHM patients from the Israeli-Palestinian population and US patients with other origins. DESIGN Case series study. PARTICIPANTS Patients with clinically suspected ACHM, cone dysfunction phenotypes, and unaffected family members were included. The protocol was approved by the local institutional review board and informed consent was obtained from all participants. METHODS Genetic analyses included homozygosity mapping and exome sequencing. Phenotype was assessed with electroretinography (ERG), optical coherence tomography, psychophysics, and photoaversion testing. MAIN OUTCOME MEASURES Single nucleotide polymorphism microarray, exome analysis, DNA sequence analysis, visual function testing including ERG, and photoaversion. RESULTS We identified 148 ACHM patients from 57 Israeli and Palestinian families; there were 16 CNGA3 mutations (5 novel) in 41 families and 5 CNGB3 mutations (1 novel) in 8 families. Two CNGA3 founder mutations underlie >50% of cases. These mutations lead to a high ACHM prevalence of ∼1:5000 among Arab-Muslims residing in Jerusalem. Rod ERG abnormalities (in addition to cone dysfunction) were detected in 59% of patients. Retinal structure in CNGA3 ACHM patients revealed persistent but abnormal foveal cones. Under dark- and light-adapted conditions, patients use rod-mediated pathways. Photoaversion was readily demonstrated with transition from the dark to a dim light background. CONCLUSIONS Among Israeli and Palestinian patients, CNGA3 mutations are the leading cause of ACHM. Retinal structural results support the candidacy of CNGA3 ACHM for clinical trials for therapy of cone photoreceptors. Efficacy outcome measures would include chromatic light-adapted psychophysics, with attention to the photoreceptor basis of the response, and quantitation of photoaversion.
Collapse
Affiliation(s)
- Lina Zelinger
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Artur V Cideciyan
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Susanne Kohl
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Sharon B Schwartz
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ada Rosenmann
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Dalia Eli
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Alexander Sumaroka
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Alejandro J Roman
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Xunda Luo
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Cassondra Brown
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Boris Rosin
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Anat Blumenfeld
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Bernd Wissinger
- Molecular Genetics Laboratory, Institute for Ophthalmic Research, Centre for Ophthalmology, University of Tübingen, Tübingen, Germany
| | - Samuel G Jacobson
- Department of Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Eyal Banin
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel
| | - Dror Sharon
- Department of Ophthalmology, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
| |
Collapse
|
20
|
Aboshiha J, Luong V, Cowing J, Dubis AM, Bainbridge JW, Ali RR, Webster AR, Moore AT, Fitzke FW, Michaelides M. Dark-adaptation functions in molecularly confirmed achromatopsia and the implications for assessment in retinal therapy trials. Invest Ophthalmol Vis Sci 2014; 55:6340-9. [PMID: 25168900 DOI: 10.1167/iovs.14-14910] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
PURPOSE To describe the dark-adaptation (DA) functions in subjects with molecularly proven achromatopsia (ACHM) using refined testing conditions with a view to guiding assessment in forthcoming gene therapy trials. METHODS The DA functions of nine subjects with ACHM were measured and compared with those of normal observers. The size and retinal location of the stimuli used to measure DA sensitivities were varied in four distinct testing condition sets, and the effect of altering these parameters assessed. RESULTS In three of the four testing condition sets, achromats had significantly higher mean final thresholds than normal observers, whereas in the fourth condition set they did not. A larger, more central stimulus revealed the greatest difference between the final DA thresholds of achromat and normal subjects, and also demonstrated the slowest rate of recovery among the achromat group. CONCLUSIONS In this, the largest study of DA functions in molecularly proven ACHM to date, we have identified optimal testing conditions that accentuate the relative difference between achromats and normal observers. These findings can help optimize DA testing in future trials, as well as help resolve the dichotomy in the literature regarding the normality or otherwise of DA functions in ACHM. Furthermore, the shorter testing time and less intense adaptation light used in these experiments may prove advantageous for more readily and reliably probing scotopic function in retinal disease, and be particularly valuable in the frequent post therapeutic assessments required in the context of the marked photophobia in ACHM.
Collapse
Affiliation(s)
- Jonathan Aboshiha
- UCL Institute of Ophthalmology, University College London, London, United Kingdom Moorfields Eye Hospital, London, United Kingdom
| | - Vy Luong
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Jill Cowing
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Adam M Dubis
- UCL Institute of Ophthalmology, University College London, London, United Kingdom Moorfields Eye Hospital, London, United Kingdom
| | - James W Bainbridge
- UCL Institute of Ophthalmology, University College London, London, United Kingdom Moorfields Eye Hospital, London, United Kingdom
| | - Robin R Ali
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Andrew R Webster
- UCL Institute of Ophthalmology, University College London, London, United Kingdom Moorfields Eye Hospital, London, United Kingdom
| | - Anthony T Moore
- UCL Institute of Ophthalmology, University College London, London, United Kingdom Moorfields Eye Hospital, London, United Kingdom
| | - Frederick W Fitzke
- UCL Institute of Ophthalmology, University College London, London, United Kingdom
| | - Michel Michaelides
- UCL Institute of Ophthalmology, University College London, London, United Kingdom Moorfields Eye Hospital, London, United Kingdom
| |
Collapse
|
21
|
Electroretinographic characteristics in children with infantile nystagmus syndrome and early-onset retinal dystrophies. Eur J Ophthalmol 2014; 25:33-42. [PMID: 25096283 DOI: 10.5301/ejo.5000493] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/06/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE To differentiate early-onset retinal dystrophies on the basis of electroretinogram (ERG) characteristics in children with infantile nystagmus syndrome (INS). METHODS Thirty-seven children with INS and early-onset retinal dystrophies were included, with diagnosis according to clinical and ERG findings. Three ERG protocols were used according to the child's age and 17 children were followed with 2 protocols: 27 (mean 2.1 years) were recorded with skin electrodes to flash stimulation, 16 (mean 6.5 years) with skin electrodes to full-field stimulation, and 11 (mean 12.2 years) with HK electrodes to full-field stimulation. The ERGs were compared to those of age-matched controls, with differences significant if p<0.05. RESULTS Clinical and electrophysiologic findings were in agreement across all of the children. In nine children with Leber congenital amaurosis, the scotopic and photopic ERGs were not recordable under all protocols. Six children with congenital stationary night blindness (CSNB) had electronegative scotopic ERG under all protocols, those with complete CSNB had absent rod ERG, and those with incomplete CSNB had reduced rod ERG. Eight children with achromatopsia had nonrecordable photopic and subnormal scotopic ERG under all protocols. The implicit times of the scotopic b-waves were prolonged. One child had blue-cone monochromatism and reduced photopic and normal S-cone ERG. Six children with cone-rod dystrophy without systemic disorder, and seven children with systemic disorder, had affected photopic and scotopic ERGs under all protocols. CONCLUSIONS In children with INS, some early-onset retinal dystrophies can be differentiated through ERGs, also with skin electrodes.
Collapse
|
22
|
Burgueño-Montañés C, Colunga-Cueva M. [Optical coherence tomography in the diagnosis of achromatopsia]. ACTA ACUST UNITED AC 2013; 89:70-3. [PMID: 24269402 DOI: 10.1016/j.oftal.2012.07.025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2011] [Accepted: 07/06/2012] [Indexed: 11/30/2022]
Abstract
CASE REPORT The case of a fifty five year-old male with nyctalopia, photophobia, poor colour vision and nystagmus, is presented. The initial suspected diagnoses were achromatopsia and blue-cone monochromatism, since both are clinically indistinguishable. Optical coherence tomography (OCT) showed the characteristic foveal reflectivity pattern of achromatopsia. This diagnosis was subsequently confirmed by genetic study. DISCUSSION OCT is a non-invasive diagnostic imaging method that allows tissue morphology to be observed with high resolution. Its use might be of great help to distinguish clinically similar diseases.
Collapse
|
23
|
Doucette L, Green J, Black C, Schwartzentruber J, Johnson GJ, Galutira D, Young TL. Molecular genetics of achromatopsia in Newfoundland reveal genetic heterogeneity, founder effects and the first cases of Jalili syndrome in North America. Ophthalmic Genet 2013; 34:119-29. [PMID: 23362848 DOI: 10.3109/13816810.2013.763993] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Achromatopsia (ACHM) is a severe retinal disorder characterized by an inability to distinguish colors, impaired visual acuity, photophobia and nystagmus. This rare autosomal recessive disorder of the cone photoreceptors is best known for its increased frequency due to founder effect in the Pingelapese population of the Pacific islands. Sixteen patients from Newfoundland, Canada were sequenced for mutations in the four known achromatopsia genes CNGA3, CNGB3, GNAT2, and PDE6C. The majority (n = 12) of patients were either homozygotes or compound heterozygotes for known achromatopsia alleles, two in CNGB3 (p.T383fsX and p.T296YfsX9) and three in CNGA3 (p.R283Q, p.R427C and p.L527R). Haplotype reconstruction showed that recurrent mutations p.T383fsX and p.L527R were due to a founder effect. Aggregate data from exome sequencing, segregation analysis and archived medical records support a rediagnosis of Jalili syndrome in affected siblings (n = 4) from Family 0094, which to our knowledge is the first family identified with Jalili Syndrome in North America.
Collapse
Affiliation(s)
- Lance Doucette
- Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland and Labrador, Canada
| | | | | | | | | | | | | |
Collapse
|
24
|
Wu DM, Fawzi AA. Abnormalities of Cone and Rod Function. Retina 2013. [DOI: 10.1016/b978-1-4557-0737-9.00044-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
25
|
Xu J, Morris LM, Michalakis S, Biel M, Fliesler SJ, Sherry DM, Ding XQ. CNGA3 deficiency affects cone synaptic terminal structure and function and leads to secondary rod dysfunction and degeneration. Invest Ophthalmol Vis Sci 2012; 53:1117-29. [PMID: 22247469 DOI: 10.1167/iovs.11-8168] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
PURPOSE To investigate rod function and survival after cone dysfunction and degeneration in a mouse model of cone cyclic nucleotide-gated (CNG) channel deficiency. METHODS Rod function and survival in mice with cone CNG channel subunit CNGA3 deficiency (CNGA3-/- mice) were evaluated by electroretinographic (ERG), morphometric, and Western blot analyses. The arrangement, integrity, and ultrastructure of photoreceptor terminals were investigated by immunohistochemistry and electron microscopy. RESULTS The authors found loss of cone function and cone death accompanied by impairment of rods and rod-driven signaling in CNGA3-/- mice. Scotopic ERG b-wave amplitudes were reduced by 15% at 1 month, 30% at 6 months, and 40% at 9 months and older, while scotopic a-wave amplitudes were decreased by 20% at 9 months, compared with ERGs of age-matched wild-type mice. Outer nuclear layer thickness in CNGA3-/- retina was reduced by 15% at 12 months compared with age-matched wild-type controls. This was accompanied by a 30%-40% reduction in expression of rod-specific proteins, including rhodopsin, rod transducin α-subunit, and glutamic acid-rich protein (GARP). Cone terminals in the CNGA3-/- retina showed a progressive loss of neurochemical and ultrastructural integrity. Abnormalities were observed as early as 1 month. Disorganized rod terminal ultrastructure was noted by 12 months. CONCLUSIONS These findings demonstrate secondary rod impairment and degeneration after cone degeneration in mice with cone CNG channel deficiency. Loss of cone phototransduction accompanies the compromised integrity of cone terminals. With time, rod synaptic structure, function, and viability also become compromised.
Collapse
Affiliation(s)
- Jianhua Xu
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
Bijveld MMC, Riemslag FCC, Kappers AML, Hoeben FP, van Genderen MM. An extended 15 Hz ERG protocol (2): data of normal subjects and patients with achromatopsia, CSNB1, and CSNB2. Doc Ophthalmol 2011; 123:161-72. [PMID: 21947599 DOI: 10.1007/s10633-011-9293-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2011] [Accepted: 09/12/2011] [Indexed: 10/17/2022]
Abstract
The amplitude versus flash strength curve of 15 Hz electroretinograms (ERGs) shows two minima. The minima are caused by interactions between the primary and the secondary rod pathways (first minimum), and the secondary rod pathway and the cone-driven pathway (second minimum). Furthermore, cone pathway contributions cause higher-order harmonics to occur in the responses. We measured 15 Hz ERGs in 20 healthy subjects to determine normal ranges and in patients to verify our hypotheses on the contributions of the different pathways and to investigate the clinical application. We analyzed the amplitudes and phases of the 15, 30, and 45 Hz components in the ERGs. The overall shape of the 15 Hz amplitude curves was similar in all normal subjects and showed two minima. The 30 and 45 Hz amplitude curves increased for stimuli of high flash strengths indicating cone pathway contributions. The 15 Hz amplitude curve of the responses of an achromat was similar to that of the normal subjects for low flash strengths and showed a minimum, indicating normal primary and secondary rod pathway function. There was no second minimum, and there were no higher-order harmonics, consistent with absent cone pathway function. The 15 Hz ERGs in CSNB1 and CSNB2 patients were similar and of low amplitude for flash strengths just above where the first minimum normally occurs. We could determine that in the CSNB1 patients, the responses originate from the cone pathway, while in the CSNB2 patients, the responses originate from the secondary rod pathway.
Collapse
Affiliation(s)
- Mieke M C Bijveld
- Bartiméus, Institute for the Visually Impaired, PO Box 1300, 3700 BA, Zeist, The Netherlands.
| | | | | | | | | |
Collapse
|
27
|
Garry D, Hansen RM, Moskowitz A, Elias ER, Irons M, Fulton AB. Cone ERG responses in patients with Smith-Lemli-Opitz Syndrome (SLOS). Doc Ophthalmol 2010; 121:85-91. [PMID: 20440536 PMCID: PMC2935499 DOI: 10.1007/s10633-010-9232-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Accepted: 04/15/2010] [Indexed: 12/26/2022]
Abstract
PURPOSE To evaluate cone and cone-driven retinal function in patients with Smith-Lemli-Opitz syndrome (SLOS), a condition characterized by low cholesterol. Rod and rod-driven function in patients with SLOS are known to be abnormal. METHODS Electroretinographic (ERG) responses to full-field stimuli presented on a steady, rod suppressing background were recorded in 13 patients who had received long-term cholesterol supplementation. Cone photoresponse sensitivity (S(CONE)) and saturated amplitude (R(CONE)) parameters were estimated using a model of the activation of phototransduction, and post-receptor b-wave and 30 Hz flicker responses were analyzed. The responses of the patients were compared to those of control subjects (N = 13). RESULTS Although average values of both S(CONE) and R(CONE) were lower than in controls, the differences were not statistically significant. Post-receptor b-wave amplitude and implicit time and flicker responses were normal. CONCLUSIONS The normal cone function contrasts with the significant abnormalities in rod function that were found previously in these same patients. Possibly, cholesterol supplementation has a greater protective effect on cones than on rods as has been demonstrated in the rat model of SLOS.
Collapse
Affiliation(s)
- Deirdre Garry
- Department of Ophthalmology Children's Hospital Boston & Harvard Medical School 300 Longwood Avenue Boston, MA 02115
- Division of Genetics Children's Hospital Boston & Harvard Medical School 300 Longwood Avenue Boston, MA 02115
| | - Ronald M. Hansen
- Department of Ophthalmology Children's Hospital Boston & Harvard Medical School 300 Longwood Avenue Boston, MA 02115
| | - Anne Moskowitz
- Department of Ophthalmology Children's Hospital Boston & Harvard Medical School 300 Longwood Avenue Boston, MA 02115
| | - Ellen R. Elias
- Coordinated Care Service Children's Hospital Boston & Harvard Medical School 300 Longwood Avenue Boston, MA 02115
| | - Mira Irons
- Division of Genetics Children's Hospital Boston & Harvard Medical School 300 Longwood Avenue Boston, MA 02115
| | - Anne B. Fulton
- Department of Ophthalmology Children's Hospital Boston & Harvard Medical School 300 Longwood Avenue Boston, MA 02115
| |
Collapse
|
28
|
Type 3 deiodinase, a thyroid-hormone-inactivating enzyme, controls survival and maturation of cone photoreceptors. J Neurosci 2010; 30:3347-57. [PMID: 20203194 DOI: 10.1523/jneurosci.5267-09.2010] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Maturation of the mammalian nervous system requires adequate provision of thyroid hormone and mechanisms that enhance tissue responses to the hormone. Here, we report that the development of cones, the photoreceptors for daylight and color vision, requires protection from thyroid hormone by type 3 deiodinase, a thyroid hormone-inactivating enzyme. Type 3 deiodinase, encoded by Dio3, is expressed in the immature mouse retina. In Dio3(-/-) mice, approximately 80% of cones are lost through neonatal cell death. Cones that express opsin photopigments for response to both short (S) and medium-long (M) wavelength light are lost. Rod photoreceptors, which mediate dim light vision, remain essentially intact. Excessive thyroid hormone in wild-type pups also eliminates cones. Cone loss is mediated by cone-specific thyroid hormone receptor beta2 (TRbeta2) as deletion of TRbeta2 rescues cones in Dio3(-/-) mice. However, rescued cones respond to short but not longer wavelength light because TRbeta2 under moderate hormonal stimulation normally induces M opsin and controls the patterning of M and S opsins over the retina. The results suggest that type 3 deiodinase limits hormonal exposure of the cone to levels that safeguard both cone survival and the patterning of opsins that is required for cone function.
Collapse
|
29
|
Abstract
PURPOSE To provide an overview of some of our electroretinographic (ERG) and psychophysical studies of normal development of rod function and their application to retinopathy of prematurity (ROP). METHODS ERG responses to full-field stimuli were recorded from dark adapted subjects. Rod photoreceptor sensitivity (SROD) was calculated by fit of a biochemical model of the activation of phototransduction to the ERG a-wave. Dark adapted psychophysical thresholds for detecting 2 degrees spots in parafoveal (10 degrees eccentric) and peripheral (30 degrees eccentric) retina were measured and the difference between the thresholds, Delta10-30, was examined as a function of age. SROD and Delta10-30 in term born and former preterm subjects were compared. RESULTS In term born infants, (1) the normal developmental increase in SROD changes proportionately with the amount of rod visual pigment, rhodopsin, and (2) rod-mediated function in central retina is immature compared with that in peripheral retina. In subjects born prematurely, deficits in SROD persist long after active ROP has resolved. Maturation of rod-mediated thresholds in the central retina is prolonged by mild ROP. CONCLUSIONS Characterization of the development of normal rod and rod-mediated function provides a foundation for understanding ROP.
Collapse
|