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Sanchez-Bretano A, Keeling E, Scott JA, Lynn SA, Soundara-Pandi SP, Macdonald SL, Newall T, Griffiths H, Lotery AJ, Ratnayaka JA, Self JE, Lee H. Human equivalent doses of L-DOPA rescues retinal morphology and visual function in a murine model of albinism. Sci Rep 2023; 13:17173. [PMID: 37821525 PMCID: PMC10567794 DOI: 10.1038/s41598-023-44373-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 10/07/2023] [Indexed: 10/13/2023] Open
Abstract
L-DOPA is deficient in the developing albino eye, resulting in abnormalities of retinal development and visual impairment. Ongoing retinal development after birth has also been demonstrated in the developing albino eye offering a potential therapeutic window in humans. To study whether human equivalent doses of L-DOPA/Carbidopa administered during the crucial postnatal period of neuroplasticity can rescue visual function, OCA C57BL/6 J-c2J OCA1 mice were treated with a 28-day course of oral L-DOPA/Carbidopa at 3 different doses from 15 to 43 days postnatal age (PNA) and for 3 different lengths of treatment, to identify optimum dosage and treatment length. Visual electrophysiology, acuity, and retinal morphology were measured at 4, 5, 6, 12 and 16 weeks PNA and compared to untreated C57BL/6 J (WT) and OCA1 mice. Quantification of PEDF, βIII-tubulin and syntaxin-3 expression was also performed. Our data showed impaired retinal morphology, decreased retinal function and lower visual acuity in untreated OCA1 mice compared to WT mice. These changes were diminished or eliminated when treated with higher doses of L-DOPA/Carbidopa. Our results demonstrate that oral L-DOPA/Carbidopa supplementation at human equivalent doses during the postnatal critical period of retinal neuroplasticity can rescue visual retinal morphology and retinal function, via PEDF upregulation and modulation of retinal synaptogenesis, providing a further step towards developing an effective treatment for albinism patients.
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Affiliation(s)
- Aida Sanchez-Bretano
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Eloise Keeling
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Jennifer A Scott
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Savannah A Lynn
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Sudha Priya Soundara-Pandi
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Sarah L Macdonald
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Tutte Newall
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Helen Griffiths
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Andrew J Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, UK
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
| | - Jay E Self
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, UK
| | - Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Sir Henry Wellcome Laboratories, Southampton University Hospital, South Block Mail Point 806, Level D, Southampton, SO16 6YD, UK.
- Eye Unit, University Hospital Southampton NHS Foundation Trust, Tremona Road, Southampton, SO16 6YD, UK.
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Prieur DS, Francius C, Gaspar P, Mason CA, Rebsam A. Semaphorin-6D and Plexin-A1 Act in a Non-Cell-Autonomous Manner to Position and Target Retinal Ganglion Cell Axons. J Neurosci 2023; 43:5769-5778. [PMID: 37344233 PMCID: PMC10423046 DOI: 10.1523/jneurosci.0072-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/04/2023] [Accepted: 05/01/2023] [Indexed: 06/23/2023] Open
Abstract
Semaphorins and Plexins form ligand/receptor pairs that are crucial for a wide range of developmental processes from cell proliferation to axon guidance. The ability of semaphorins to act both as signaling receptors and ligands yields a multitude of responses. Here, we describe a novel role for Semaphorin-6D (Sema6D) and Plexin-A1 in the positioning and targeting of retinogeniculate axons. In Plexin-A1 or Sema6D mutant mice of either sex, the optic tract courses through, rather than along, the border of the dorsal lateral geniculate nucleus (dLGN), and some retinal axons ectopically arborize adjacent and lateral to the optic tract rather than defasciculating and entering the target region. We find that Sema6D and Plexin-A1 act together in a dose-dependent manner, as the number of the ectopic retinal projections is altered in proportion to the level of Sema6D or Plexin-A1 expression. Moreover, using retinal in utero electroporation of Sema6D or Plexin-A1 shRNA, we show that Sema6D and Plexin-A1 are both required in retinal ganglion cells for axon positioning and targeting. Strikingly, nonelectroporated retinal ganglion cell axons also mistarget in the tract region, indicating that Sema6D and Plexin-A1 can act non-cell-autonomously, potentially through axon-axon interactions. These data provide novel evidence for a dose-dependent and non-cell-autonomous role for Sema6D and Plexin-A1 in retinal axon organization in the optic tract and dLGN.SIGNIFICANCE STATEMENT Before innervating their central brain targets, retinal ganglion cell axons fasciculate in the optic tract and then branch and arborize in their target areas. Upon deletion of the guidance molecules Plexin-A1 or Semaphorin-6D, the optic tract becomes disorganized near and extends within the dorsal lateral geniculate nucleus. In addition, some retinal axons form ectopic aggregates within the defasciculated tract. Sema6D and Plexin-A1 act together as a receptor-ligand pair in a dose-dependent manner, and non-cell-autonomously, to produce this developmental aberration. Such a phenotype highlights an underappreciated role for axon guidance molecules in tract cohesion and appropriate defasciculation near, and arborization within, targets.
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Affiliation(s)
- Delphine S Prieur
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, Paris, 75005, France
- Sorbonne Université, Paris, 75005, France
- Institut du Fer à Moulin, Paris, 75005, France
| | - Cédric Francius
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, Paris, 75005, France
- Sorbonne Université, Paris, 75005, France
- Institut du Fer à Moulin, Paris, 75005, France
| | - Patricia Gaspar
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, Paris, 75005, France
- Sorbonne Université, Paris, 75005, France
- Institut du Fer à Moulin, Paris, 75005, France
| | - Carol A Mason
- Departments of Pathology and Cell Biology, Neuroscience, and Ophthalmology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027
| | - Alexandra Rebsam
- Institut National de la Santé et de la Recherche Médicale, Unité Mixte de Recherche-S 839, Paris, 75005, France
- Sorbonne Université, Paris, 75005, France
- Institut du Fer à Moulin, Paris, 75005, France
- Sorbonne Université, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut de la Vision, Paris, F-75012, France
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A laser-induced mouse model of progressive retinal degeneration with central sparing displays features of parafoveal geographic atrophy. Sci Rep 2023; 13:4194. [PMID: 36918701 PMCID: PMC10014848 DOI: 10.1038/s41598-023-31392-3] [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: 12/13/2022] [Accepted: 03/10/2023] [Indexed: 03/16/2023] Open
Abstract
There are no disease-modifying treatments available for geographic atrophy (GA), the advanced form of dry age-related macular degeneration. Current murine models fail to fully recapitulate the features of GA and thus hinder drug discovery. Here we describe a novel mouse model of retinal degeneration with hallmark features of GA. We used an 810 nm laser to create a retinal lesion with central sparing (RLCS), simulating parafoveal atrophy observed in patients with progressive GA. Laser-induced RLCS resulted in progressive GA-like pathology with the development of a confluent atrophic lesion. We demonstrate significant changes to the retinal structure and thickness in the central unaffected retina over a 24-week post-laser period, confirmed by longitudinal optical coherence tomography scans. We further show characteristic features of progressive GA, including a gradual reduction in the thickness of the central, unaffected retina and of total retinal thickness. Histological changes observed in the RLCS correspond to GA pathology, which includes the collapse of the outer nuclear layer, increased numbers of GFAP + , CD11b + and FcγRI + cells, and damage to cone and rod photoreceptors. We demonstrate a laser-induced mouse model of parafoveal GA progression, starting at 2 weeks post-laser and reaching confluence at 24 weeks post-laser. This 24-week time-frame in which GA pathology develops, provides an extended window of opportunity for proof-of-concept evaluation of drugs targeting GA. This time period is an added advantage compared to several existing models of geographic atrophy.
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Lee H, Purohit R, Sheth V, Maconachie G, Tu Z, Thomas MG, Pilat A, McLean RJ, Proudlock FA, Gottlob I. Retinal Development in Infants and Young Children With Albinism: Evidence for Plasticity in Early Childhood. Am J Ophthalmol 2023; 245:202-211. [PMID: 36084688 DOI: 10.1016/j.ajo.2022.08.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 08/23/2022] [Accepted: 08/23/2022] [Indexed: 11/13/2022]
Abstract
MEETING PRESENTATION Presented at the 2016 Association for Research in Vision and Ophthalmology meeting and at the 2015 British Isles Paediatric, Ophthalmology and Strabismus Association meeting. PURPOSE To investigate the time course of foveal development after birth in infants with albinism. DESIGN Prospective, comparative cohort optical coherence tomography study. METHODS Thirty-six children with albinism were recruited. All participants were between 0 and 6 years of age and were seen at Leicester Royal Infirmary. A total of 181 mixed cross-sectional and longitudinal optical coherence tomography examinations were obtained, which were analyzed for differences in retinal development in comparison to 297 cross-sectional control examinations. RESULTS Normal retinal development involves migration of the inner retinal layers (IRLs) away from the fovea, migration of the cone photoreceptors into the fovea, and elongation of the outer retinal layers (ORLs) over time. In contrast to controls where IRL migration from the fovea was almost completed at birth, a significant degree of IRL migration was taking place after birth in albinism, before arresting prematurely at 40 months postmenstrual age (PMA). This resulted in a significantly thicker central macular thickness in albinism (Δ = 83.8 ± 6.1, P < .0001 at 69 months PMA). There was evidence of ongoing foveal ORL elongation in albinism, although reduced in amplitude compared with control subjects after 21 months PMA (Δ = -17.3 ± 4.3, P < .0001). CONCLUSIONS We have demonstrated evidence of ongoing retinal development in young children with albinism, albeit at a reduced rate and magnitude compared with control subjects. The presence of a period of retinal plasticity in early childhood raises the possibility that treatment modalities, which aim to improve retinal development, could potentially optimize visual function in albinism.
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Affiliation(s)
- Helena Lee
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom.
| | - Ravi Purohit
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Viral Sheth
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Gail Maconachie
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Zhanhan Tu
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Mervyn G Thomas
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Anastasia Pilat
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Rebecca J McLean
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Frank A Proudlock
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Irene Gottlob
- From the University of Leicester Ulverscroft Eye Unit, Leicester Royal Infirmary, Leicester, United Kingdom
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Zhang C, Wu QQ, Hou Y, Wang Q, Zhang GJ, Zhao WB, Wang X, Wang H, Li WG. Ophthalmologic problems correlates with cognitive impairment in patients with Parkinson's disease. Front Neurosci 2022; 16:928980. [PMID: 36278010 PMCID: PMC9583907 DOI: 10.3389/fnins.2022.928980] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 09/08/2022] [Indexed: 11/29/2022] Open
Abstract
Objective Visual impairment is a common non-motor symptom (NMS) in patients with Parkinson's disease (PD) and its implications for cognitive impairment remain controversial. We wished to survey the prevalence of visual impairment in Chinese Parkinson's patients based on the Visual Impairment in Parkinson's Disease Questionnaire (VIPD-Q), identify the pathogens that lead to visual impairment, and develop a predictive model for cognitive impairment risk in Parkinson's based on ophthalmic parameters. Methods A total of 205 patients with Parkinson's disease and 200 age-matched controls completed the VIPD-Q and underwent neuro-ophthalmologic examinations, including ocular fundus photography and optical coherence tomography. We conducted nomogram analysis and the predictive model was summarized using the multivariate logistic and LASSO regression and verified via bootstrap validation. Results One or more ophthalmologic symptoms were present in 57% of patients with Parkinson's disease, compared with 14% of the controls (χ2-test; p < 0.001). The visual impairment questionnaire showed good sensitivity and specificity (area under the curve [AUC] = 0.918, p < 0.001) and a strong correlation with MoCA scores (Pearson r = −0.4652, p < 0.001). Comparing visual impairment scores between pre- and post-deep brain stimulation groups showed that DBS improved visual function (U-test, p < 0.001). The thickness of the retinal nerve fiber layer and vessel percentage area predicted cognitive impairment in PD. Interpretation The study findings provide novel mechanistic insights into visual impairment and cognitive decline in Parkinson's disease. The results inform an effective tool for predicting cognitive deterioration in Parkinson's based on ophthalmic parameters.
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Affiliation(s)
- Chao Zhang
- Department of Neurosurgery, Qilu Hospital of Shandong University, Jinan, China
- Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
| | - Qian-qian Wu
- Department of Neurosurgery, Qilu Hospital of Shandong University, Jinan, China
| | - Ying Hou
- Department of Neurology, Qilu Hospital of Shandong University, Jinan, China
| | - Qi Wang
- Department of Gerontology, Shandong Provincial Qianfoshan Hospital, Jinan, China
| | - Guang-jian Zhang
- Department of Neurology, Weifang People's Hospital, Weifang, China
| | - Wen-bo Zhao
- Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
| | - Xu Wang
- Institute of Brain and Brain-Inspired Science, Shandong University, Jinan, China
| | - Hong Wang
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, China
| | - Wei-guo Li
- Department of Neurosurgery, Qilu Hospital of Shandong University, Jinan, China
- *Correspondence: Wei-guo Li
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Tingaud-Sequeira A, Mercier E, Michaud V, Pinson B, Gazova I, Gontier E, Decoeur F, McKie L, Jackson IJ, Arveiler B, Javerzat S. The Dct−/− Mouse Model to Unravel Retinogenesis Misregulation in Patients with Albinism. Genes (Basel) 2022; 13:genes13071164. [PMID: 35885947 PMCID: PMC9324463 DOI: 10.3390/genes13071164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 11/16/2022] Open
Abstract
We have recently identified DCT encoding dopachrome tautomerase (DCT) as the eighth gene for oculocutaneous albinism (OCA). Patients with loss of function of DCT suffer from eye hypopigmentation and retinal dystrophy. Here we investigate the eye phenotype in Dct−/− mice. We show that their retinal pigmented epithelium (RPE) is severely hypopigmented from early stages, contrasting with the darker melanocytic tissues. Multimodal imaging reveals specific RPE cellular defects. Melanosomes are fewer with correct subcellular localization but disrupted melanization. RPE cell size is globally increased and heterogeneous. P-cadherin labeling of Dct−/− newborn RPE reveals a defect in adherens junctions similar to what has been described in tyrosinase-deficient Tyrc/c embryos. The first intermediate of melanin biosynthesis, dihydroxyphenylalanine (L-Dopa), which is thought to control retinogenesis, is detected in substantial yet significantly reduced amounts in Dct−/− postnatal mouse eyecups. L-Dopa synthesis in the RPE alone remains to be evaluated during the critical period of retinogenesis. The Dct−/− mouse should prove useful in understanding the molecular regulation of retinal development and aging of the hypopigmented eye. This may guide therapeutic strategies to prevent vision deficits in patients with albinism.
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Affiliation(s)
- Angèle Tingaud-Sequeira
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
| | - Elina Mercier
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
| | - Vincent Michaud
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
- Molecular Genetics Laboratory, Bordeaux University Hospital, F-33076 Bordeaux, France
| | - Benoît Pinson
- SAM, TBMcore, CNRS UAR 3427, INSERM US005, Université Bordeaux, F-33076 Bordeaux, France;
| | - Ivet Gazova
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK; (I.G.); (L.M.); (I.J.J.)
| | - Etienne Gontier
- Bordeaux Imaging Center, CNRS, INSERM, BIC, UMS 3420, US 4, University Bordeaux, F-33076 Bordeaux, France; (E.G.); (F.D.)
| | - Fanny Decoeur
- Bordeaux Imaging Center, CNRS, INSERM, BIC, UMS 3420, US 4, University Bordeaux, F-33076 Bordeaux, France; (E.G.); (F.D.)
| | - Lisa McKie
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK; (I.G.); (L.M.); (I.J.J.)
| | - Ian J. Jackson
- MRC Human Genetics Unit, University of Edinburgh, Edinburgh EH4 2XU, UK; (I.G.); (L.M.); (I.J.J.)
| | - Benoît Arveiler
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
- Molecular Genetics Laboratory, Bordeaux University Hospital, F-33076 Bordeaux, France
| | - Sophie Javerzat
- Rare Diseases Genetics and Metabolism, INSERM U1211, SBM Department, University of Bordeaux, F-33076 Bordeaux, France; (A.T.-S.); (E.M.); (V.M.); (B.A.)
- Correspondence:
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Lin S, Sanchez-Bretaño A, Leslie JS, Williams KB, Lee H, Thomas NS, Callaway J, Deline J, Ratnayaka JA, Baralle D, Schmitt MA, Norman CS, Hammond S, Harlalka GV, Ennis S, Cross HE, Wenger O, Crosby AH, Baple EL, Self JE. Evidence that the Ser192Tyr/Arg402Gln in cis Tyrosinase gene haplotype is a disease-causing allele in oculocutaneous albinism type 1B (OCA1B). NPJ Genom Med 2022; 7:2. [PMID: 35027574 PMCID: PMC8758782 DOI: 10.1038/s41525-021-00275-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 11/19/2021] [Indexed: 01/09/2023] Open
Abstract
Oculocutaneous albinism type 1 (OCA1) is caused by pathogenic variants in the TYR (tyrosinase) gene which encodes the critical and rate-limiting enzyme in melanin synthesis. It is the most common OCA subtype found in Caucasians, accounting for ~50% of cases worldwide. The apparent 'missing heritability' in OCA is well described, with ~25-30% of clinically diagnosed individuals lacking two clearly pathogenic variants. Here we undertook empowered genetic studies in an extensive multigenerational Amish family, alongside a review of previously published literature, a retrospective analysis of in-house datasets, and tyrosinase activity studies. Together this provides irrefutable evidence of the pathogenicity of two common TYR variants, p.(Ser192Tyr) and p.(Arg402Gln) when inherited in cis alongside a pathogenic TYR variant in trans. We also show that homozygosity for the p.(Ser192Tyr)/p.(Arg402Gln) TYR haplotype results in a very mild, but fully penetrant, albinism phenotype. Together these data underscore the importance of including the TYR p.(Ser192Tyr)/p.(Arg402Gln) in cis haplotype as a pathogenic allele causative of OCA, which would likely increase molecular diagnoses in this missing heritability albinism cohort by 25-50%.
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Affiliation(s)
- Siying Lin
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
| | - Aida Sanchez-Bretaño
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Joseph S Leslie
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
| | - Katie B Williams
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - N Simon Thomas
- Faculty of Medicine, University of Southampton, Southampton, UK
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
| | - Jonathan Callaway
- Faculty of Medicine, University of Southampton, Southampton, UK
- Wessex Regional Genetics Laboratory, Salisbury District Hospital, Salisbury, UK
| | - James Deline
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - J Arjuna Ratnayaka
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Diana Baralle
- Human Development and Health, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Melanie A Schmitt
- University of Wisconsin School of Medicine and Public Health, Department of Ophthalmology & Visual Sciences, Madison, WI, USA
| | - Chelsea S Norman
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
- The Rosalind Franklin Institute, Rutherford Appleton Laboratories, Harwell Science and Innovation Campus, Didcot, UK
| | - Sheri Hammond
- Center for Special Children, Vernon Memorial Healthcare, La Farge, WI, USA
| | - Gaurav V Harlalka
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK
- Rajarshi Shahu College of Pharmacy, Malvihir, Buldana, India
| | - Sarah Ennis
- Department of Human Genetics and Genomic Medicine, University of Southampton, Southampton, UK
| | - Harold E Cross
- Department of Ophthalmology, University of Arizona College of Medicine, Tucson, AZ, USA
| | - Olivia Wenger
- New Leaf Clinic, PO Box 336, 16014 East Chestnut Street, Mount Eaton, OH, 44691, USA
- Department of Pediatrics, Akron Children's Hospital, 214 West Bowery Street, Akron, OH, 44308, USA
| | - Andrew H Crosby
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK.
| | - Emma L Baple
- RILD Wellcome Wolfson Centre, Royal Devon & Exeter NHS Foundation Trust, Barrack Road, Exeter, UK.
- Peninsula Clinical Genetics Service, Royal Devon & Exeter Hospital (Heavitree), Gladstone Road, Exeter, UK.
| | - Jay E Self
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK.
- Southampton Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK.
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Pillay E, Naidoo T, Asmal K, Maliwa L, Mchunua S, van Staden DB, Rampersad N. Characterization of Retinal Thickness in Individuals with Albinism: Baseline Data for a Black South African Population. CLINICAL OPTOMETRY 2021; 13:15-22. [PMID: 33505177 PMCID: PMC7829131 DOI: 10.2147/opto.s273141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 11/03/2020] [Indexed: 06/12/2023]
Abstract
INTRODUCTION The central retina is responsible for several visual functions and continues to develop postnatally. In albinism, which is a genetic disorder characterized by impaired melanin biosynthesis, the development of the central retina is prematurely arrested and results in foveal hypoplasia. Retinal thickness measurements can be determined non-invasively using optical coherence tomography systems. This article reports on the retinal thickness measurements of individuals with albinism in South Africa to aid in the assessment and management of affected individuals. METHODS The study used a comparative research design and included 60 individuals (30 albinism and 30 controls) aged from 10 to 30 years who accessed the eye clinic at a tertiary institution in KwaZulu-Natal, South Africa. The Optovue iVue100 optical coherence tomographer was used to measure retinal thickness in the nine Early Treatment Diabetic Retinopathy Study (ETDRS) sectors including the central foveal, parafoveal and perifoveal regions. Study data were analysed using descriptive and inferential statistics. RESULTS The mean central foveal thickness was significantly higher in individuals with albinism compared with controls (289 µm versus 239 µm, p < 0.001). In contrast, control participants showed thicker retinal thickness measurements in the other ETDRS sectors (p < 0.001). The nasal and temporal quadrants were thickest and thinnest, respectively, in the parafoveal and perifoveal regions for the albinism and control groups. CONCLUSION Individuals with albinism, aged from 10 to 30 years, have higher central foveal thickness but thinner retinal thickness measurements in the parafoveal and perifoveal regions. Optometric personnel should consider these measurements when assessing individuals with albinism with foveal retinal diseases.
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Affiliation(s)
- Ethan Pillay
- Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, DurbanX54001, South Africa
| | - Thiroshnee Naidoo
- Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, DurbanX54001, South Africa
| | - Khadija Asmal
- Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, DurbanX54001, South Africa
| | - Lilitha Maliwa
- Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, DurbanX54001, South Africa
| | - Sinenhlanhla Mchunua
- Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, DurbanX54001, South Africa
| | - Diane Beverly van Staden
- Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, DurbanX54001, South Africa
| | - Nishanee Rampersad
- Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, DurbanX54001, South Africa
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9
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Schidlowski L, Liebert F, Iankilevich PG, Rebellato PRO, Rocha RA, Almeida NAP, Jain A, Wu Y, Itan Y, Rosati R, Prando C. Non-syndromic Oculocutaneous Albinism: Novel Genetic Variants and Clinical Follow Up of a Brazilian Pediatric Cohort. Front Genet 2020; 11:397. [PMID: 32411182 PMCID: PMC7198815 DOI: 10.3389/fgene.2020.00397] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Oculocutaneous albinism (OCA) is a genetic disorder characterized by skin, hair, and eye hypopigmentation due to a reduction or absence of melanin. Clinical manifestations include vision problems and a high susceptibility to skin cancer. In its non-syndromic form, OCA is associated with six genes and one chromosomal region. Because OCA subtypes are not always clinically distinguishable, molecular analysis has become an important tool for classifying types of OCA, which facilitates genetic counseling and can guide the development of new therapies. We studied eight Brazilian individuals aged 1.5–18 years old with clinical diagnosis of OCA. Assessment of ophthalmologic characteristics showed results consistent with albinism, including reduced visual acuity, nystagmus, and loss of stereoscopic vision. We also observed the appearance of the strabismus and changes in static refraction over a 2-year period. Dermatologic evaluation showed that no participants had preneoplastic skin lesions, despite half of the participants reporting insufficient knowledge about skin care in albinism. Whole-exome and Sanger sequencing revealed eight different mutations: six in the TYR gene and two in the SLC45A2 gene, of which one was novel and two were described in a population study but were not previously associated with the OCA phenotype. We performed two ophthalmological evaluations, 2 years apart; and one dermatological evaluation. To the best of our knowledge, this is the first study to perform clinical follow-up and genetic analysis of a Brazilian cohort with albinism. Here, we report three new OCA causing mutations.
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Affiliation(s)
- Laire Schidlowski
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | - Fernando Liebert
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | | | | | | | | | - Aayushee Jain
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Yiming Wu
- The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Yuval Itan
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States.,The Charles Bronfman Institute for Personalized Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Roberto Rosati
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil
| | - Carolina Prando
- Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Brazil.,Faculdades Pequeno Príncipe, Curitiba, Brazil.,Hospital Pequeno Príncipe, Curitiba, Brazil
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10
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Figueroa AG, McKay BS. A G-Protein Coupled Receptor and Macular Degeneration. Cells 2020; 9:cells9040910. [PMID: 32276449 PMCID: PMC7226737 DOI: 10.3390/cells9040910] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/31/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible blindness in the world. The risk of AMD increases with age and is most common among the white population. Here, we discuss the convergence of factors related to race, pigmentation, and susceptibility to AMD, where the primary defect occurs in retinal support cells, the retinal pigment epithelium (RPE). We explore whether the observed racial bias in AMD incidence is related to innate differences in the basal level of pigmentation between races, and whether the pigmentation pathway activity in the RPE might protect from retinal degeneration. More specifically, we explore whether the downstream signaling activity of GPR143, a G-protein coupled receptor in the pigmentation pathway, might underly the racial bias of AMD and be a target to prevent the disease. Lastly, we summarize the past findings of a large retrospective study that investigated the relationship between the stimulation of GPR143 with L-DOPA, the pigmentation pathway, and AMD, to potentially help develop new ways to prevent or treat AMD. The reader of this review will come to understand the racial bias of AMD, which is related to the function of the RPE.
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11
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Lee H, Scott J, Griffiths H, Self JE, Lotery A. Oral levodopa rescues retinal morphology and visual function in a murine model of human albinism. Pigment Cell Melanoma Res 2019; 32:657-671. [PMID: 30851223 PMCID: PMC6766973 DOI: 10.1111/pcmr.12782] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/07/2019] [Accepted: 03/04/2019] [Indexed: 01/10/2023]
Abstract
Albinism is a group of disorders characterized by pigment deficiency and abnormal retinal development. Despite being a common cause for visual impairment worldwide, there is a paucity of treatments and patients typically suffer lifelong visual disability. Residual plasticity of the developing retina in young children with albinism has been demonstrated, suggesting a post-natal window for therapeutic rescue. L-3, 4 dihydroxyphenylalanine (L-DOPA), a key signalling molecule which is essential for normal retinal development, is known to be deficient in albinism. In this study, we demonstrate for the first time that post-natal L-DOPA supplementation can rescue retinal development, morphology and visual function in a murine model of human albinism, but only if administered from birth or 15 days post-natal age.
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Affiliation(s)
- Helena Lee
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Jennifer Scott
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK
| | - Helen Griffiths
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK
| | - Jay E Self
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Andrew Lotery
- Clinical and Experimental Sciences, Faculty of Medicine, Sir Henry Wellcome Laboratories, Southampton University Hospital, University of Southampton, Southampton, UK.,Eye Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK
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