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Bjeloš M, Ćurić A, Bušić M, Rak B, Kuzmanović Elabjer B. Genetic Linkage between CAPN5 and TYR Variants in the Context of Albinism and Autosomal Dominant Neovascular Inflammatory Vitreoretinopathy Absence: A Case Report. Int J Mol Sci 2024; 25:6442. [PMID: 38928147 PMCID: PMC11204092 DOI: 10.3390/ijms25126442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 06/05/2024] [Accepted: 06/10/2024] [Indexed: 06/28/2024] Open
Abstract
We present a case involving a patient whose clinical phenotype aligns with oculocutaneous albinism (OCA), yet exhibits a complex genotype primarily characterized by variants of unknown significance (VUS). An 11-year-old boy manifested iris hypopigmentation and translucency, pronounced photophobia, diminished visual acuity and stereopsis, nystagmus, reduced pigmentation of the retina, and foveal hypoplasia. Genetic testing was performed. A heterozygous missense VUS CAPN5 c.230A>G, p.(Gln77Arg), a heterozygous missense VUS TYR c.1307G>C, p.(Gly436Ala), and a heterozygous missense variant TYR c.1205G>A, p.(Arg402Gln) which was classified as a risk factor, were identified. We hypothesized that the TYR c.1307G>C, p.(Gly436Ala) variant is in genetic disequilibrium with the TYR c.1205G>A, p.(Arg402Gln) variant leading to deficient expression of melanogenic enzymes in retinal cells, resulting in the manifestation of mild OCA. Additionally, this study represents the case where we did not detect chiasmal misrouting in visual evoked potentials, nor did we observe a shift in the distribution of ganglion cell thickness from a temporal to a central position. Moreover, our patient's case supports the probable benign nature of the CAPN5 c.230A>G, p.(Gln77Arg) variant.
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Affiliation(s)
- Mirjana Bjeloš
- University Eye Department, Reference Center of the Ministry of Health of the Republic of Croatia for Inherited Retinal Dystrophies, Reference Center of the Ministry of Health of the Republic of Croatia for Pediatric Ophthalmology and Strabismus, University Hospital “Sveti Duh”, 10000 Zagreb, Croatia; (M.B.); (A.Ć.); (B.R.); (B.K.E.)
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
- Faculty of Dental Medicine and Health Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Ana Ćurić
- University Eye Department, Reference Center of the Ministry of Health of the Republic of Croatia for Inherited Retinal Dystrophies, Reference Center of the Ministry of Health of the Republic of Croatia for Pediatric Ophthalmology and Strabismus, University Hospital “Sveti Duh”, 10000 Zagreb, Croatia; (M.B.); (A.Ć.); (B.R.); (B.K.E.)
- Faculty of Dental Medicine and Health Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Mladen Bušić
- University Eye Department, Reference Center of the Ministry of Health of the Republic of Croatia for Inherited Retinal Dystrophies, Reference Center of the Ministry of Health of the Republic of Croatia for Pediatric Ophthalmology and Strabismus, University Hospital “Sveti Duh”, 10000 Zagreb, Croatia; (M.B.); (A.Ć.); (B.R.); (B.K.E.)
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
- Faculty of Dental Medicine and Health Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
| | - Benedict Rak
- University Eye Department, Reference Center of the Ministry of Health of the Republic of Croatia for Inherited Retinal Dystrophies, Reference Center of the Ministry of Health of the Republic of Croatia for Pediatric Ophthalmology and Strabismus, University Hospital “Sveti Duh”, 10000 Zagreb, Croatia; (M.B.); (A.Ć.); (B.R.); (B.K.E.)
| | - Biljana Kuzmanović Elabjer
- University Eye Department, Reference Center of the Ministry of Health of the Republic of Croatia for Inherited Retinal Dystrophies, Reference Center of the Ministry of Health of the Republic of Croatia for Pediatric Ophthalmology and Strabismus, University Hospital “Sveti Duh”, 10000 Zagreb, Croatia; (M.B.); (A.Ć.); (B.R.); (B.K.E.)
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
- Faculty of Dental Medicine and Health Osijek, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia
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Sheth V, McLean RJ, Tu Z, Ather S, Gottlob I, Proudlock FA. Visual Field Deficits in Albinism in Comparison to Idiopathic Infantile Nystagmus. Invest Ophthalmol Vis Sci 2024; 65:13. [PMID: 38319668 PMCID: PMC10854418 DOI: 10.1167/iovs.65.2.13] [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: 09/08/2023] [Accepted: 01/08/2024] [Indexed: 02/07/2024] Open
Abstract
Purpose This is the first systematic comparison of visual field (VF) deficits in people with albinism (PwA) and idiopathic infantile nystagmus (PwIIN) using static perimetry. We also compare best-corrected visual acuity (BCVA) and optical coherence tomography measures of the fovea, parafovea, and circumpapillary retinal nerve fiber layer in PwA. Methods VF testing was performed on 62 PwA and 36 PwIIN using a Humphrey Field Analyzer (SITA FAST 24-2). Mean detection thresholds for each eye were calculated, along with quadrants and central measures. Retinal layers were manually segmented in the macular region. Results Mean detection thresholds were significantly lower than normative values for PwA (-3.10 ± 1.67 dB, P << 0.0001) and PwIIN (-1.70 ± 1.54 dB, P < 0.0001). Mean detection thresholds were significantly lower in PwA compared to PwIIN (P < 0.0001) and significantly worse for left compared to right eyes in PwA (P = 0.0002) but not in PwIIN (P = 0.37). In PwA, the superior nasal VF was significantly worse than other quadrants (P < 0.05). PwIIN appeared to show a mild relative arcuate scotoma. In PwA, central detection thresholds were correlated with foveal changes in the inner and outer retina. VF was strongly correlated to BCVA in both groups. Conclusions Clear peripheral and central VF deficits exist in PwA and PwIIN, and static VF results need to be interpreted with caution clinically. Since PwA exhibit considerably lower detection thresholds compared to PwIIN, VF defects are unlikely to be due to nystagmus in PwA. In addition to horizontal VF asymmetry, PwA exhibit both vertical and interocular asymmetries, which needs further exploration.
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Affiliation(s)
- Viral Sheth
- Health Sciences School, University of Sheffield, Sheffield, Yorkshire, United Kingdom
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Rebecca J. McLean
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Zhanhan Tu
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Sarim Ather
- Oxford University Hospitals NHS Foundation Trust, Headley Way, Headington, Oxfordshire, United Kingdom
| | - Irene Gottlob
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
- Department of Neurology, Cooper University Health Care, Cooper Medical School of Rowan University, Camden, New Jersey, United States
| | - Frank A. Proudlock
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
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Proudlock FA, McLean RJ, Sheth V, Ather S, Gottlob I. Phenotypic Features Determining Visual Acuity in Albinism and the Role of Amblyogenic Factors. Invest Ophthalmol Vis Sci 2024; 65:14. [PMID: 38319667 PMCID: PMC10854414 DOI: 10.1167/iovs.65.2.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Accepted: 01/05/2024] [Indexed: 02/07/2024] Open
Abstract
Albinism is a spectrum disorder causing foveal hypoplasia, nystagmus, and hypopigmentation of the iris and fundus along with other visual deficits, which can all impact vision. Albinism is also associated with amblyogenic factors which could affect monocular visual acuity. The foveal appearance in albinism can range from mild foveal hypoplasia to that which is indistinguishable from the peripheral retina. The appearance can be quickly and easily graded using the Leicester Grading System in the clinic. However, interquartile ranges of 0.3 logMAR for the grades associated with albinism limit the accuracy of the grading system in predicting vision. Here, we discuss the potential role of nystagmus presenting evidence that it may not be a major source of variability in the prediction of visual acuity. We also show that interocular differences in visual acuity are low in albinism despite high levels of amblyogenic factors indicating that active suppression of vision in one eye in albinism is uncommon.
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Affiliation(s)
- Frank A Proudlock
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Rebecca J McLean
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
| | - Viral Sheth
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
- Health Sciences School, University of Sheffield, Sheffield, Yorkshire, United Kingdom
| | - Sarim Ather
- Oxford University Hospitals NHS Foundation Trust, Headley Way, Headington, Oxfordshire, United Kingdom
| | - Irene Gottlob
- The University of Leicester Ulverscroft Eye Unit, Psychology and Vision Sciences, University of Leicester, Robert Kilpatrick Clinical Sciences Building, Leicester Royal Infirmary, Leicester, United Kingdom
- Department of Neurology, Cooper University Health Care, Cooper Medical School of Rowan University, Camden, New Jersey, United States
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Jarrar ZA, Al-Nosairy KO, Jiang X, Lamin A, Wong D, Ansari AS, Williams KM, Sivaprasad S, Hoffmann MB, Hysi PG, Hammond CJ, Mahroo OA. Temporal-to-Nasal Macular Ganglion Cell and Inner Plexiform Layer Ratios in a Large Adult Twin Cohort: Correlations With Age and Heritability. Invest Ophthalmol Vis Sci 2024; 65:26. [PMID: 38349786 PMCID: PMC10868632 DOI: 10.1167/iovs.65.2.26] [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: 08/01/2023] [Accepted: 01/31/2024] [Indexed: 02/15/2024] Open
Abstract
Purpose Temporal-to-nasal macular ganglion cell layer thickness ratios are reduced in albinism. We explored similar ratios in a large twin cohort to investigate ranges in healthy adults, correlations with age, and heritability. Methods More than 1000 twin pairs from TwinsUK underwent macular optical coherence tomography (OCT) scans. Automated segmentation yielded thicknesses for the combined ganglion cell and inner plexiform layer (GCIPL) in Early Treatment of Diabetic Retinopathy Study subfields. Participants with diseases likely to affect these layers or segmentation accuracy were excluded. Inner and outer ratios were defined as the ratio of temporal-to-nasal GCIPL thickness for inner and outer subfields respectively. Corresponding ratios were obtained from a smaller cohort undergoing OCTs with a different device (three-dimensional (3D)-OCT, Topcon, Japan). Results Scans from 2300 twins (1150 pairs) were included (mean [SD] age, 53.9 (16.5) years). Mean (SD) inner and outer ratios were 0.89 (0.09) and 0.84 (0.11), correlating negatively with age (coefficients, -0.17 and -0.21, respectively). In males (150 pairs) ratios were higher and did not correlate significantly with age. Intrapair correlation coefficients were higher in monozygotic than dizygotic pairs; age-adjusted heritability estimates were 0.20 and 0.23 for inner and outer ratios, respectively. For the second cohort (n = 166), mean (SD) ratios were 0.93 (0.08) and 0.91 (0.09), significantly greater than for the larger cohort. Conclusions Our study gives reference values for temporal-to-nasal macular GCIPL subfield ratios. Weak negative correlations with age emerged. Genetic factors may contribute to ∼20% to 23% of the variance in healthy individuals. The ratios differ according to the OCT platform used.
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Affiliation(s)
- Zakariya A. Jarrar
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Khaldoon O. Al-Nosairy
- Department of Ophthalmology, Faculty of Medicine, Otto-von-Guericke University, Magdeburg, Germany
| | - Xiaofan Jiang
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Ali Lamin
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
| | - Dominic Wong
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Abdus S. Ansari
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Katie M. Williams
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Sobha Sivaprasad
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
| | - Michael B. Hoffmann
- Department of Ophthalmology, Faculty of Medicine, Otto-von-Guericke University, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Sachsen-Anhalt, Germany
| | - Pirro G. Hysi
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Christopher J. Hammond
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
| | - Omar A. Mahroo
- Section of Ophthalmology, King's College London, St. Thomas’ Hospital Campus, London, United Kingdom
- Department of Twin Research and Genetic Epidemiology, King's College London, London, United Kingdom
- NIHR Biomedical Research Centre at Moorfields Eye Hospital and the UCL Institute of Ophthalmology, London, United Kingdom
- Institute of Ophthalmology, University College London, London, United Kingdom
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Pilat A, McLean RJ, Vanina A, Dineen RA, Gottlob I. Clinical features and imaging characteristics in achiasmia. Brain Commun 2023; 5:fcad219. [PMID: 37680693 PMCID: PMC10481774 DOI: 10.1093/braincomms/fcad219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 05/24/2023] [Accepted: 08/21/2023] [Indexed: 09/09/2023] Open
Abstract
Achiasmia is a rare visual pathway maldevelopment with reduced decussation of the axons in the optic chiasm. Our aim was to investigate clinical characteristics, macular, optic nerve and brain morphology in achiasmia. A prospective, cross-sectional, observational study of 12 participants with achiasmia [8 males and 4 females; 29.6 ± 18.4 years (mean ± standard deviation)] and 24 gender-, age-, ethnicity- and refraction-matched healthy controls was done. Full ophthalmology assessment, eye movement recording, a high-resolution spectral-domain optical coherence tomography of the macular and optic disc, five-channel visual-evoked responses, eye movement recordings and MRI scans of the brain and orbits were acquired. Achiasmia was confirmed in all 12 clinical participants by visual-evoked responses. Visual acuity in this group was 0.63 ± 0.19 and 0.53 ± 0.19 for the right and left eyes, respectively; most participants had mild refractive errors. All participants with achiasmia had see-saw nystagmus and no measurable stereo vision. Strabismus and abnormal head position were noted in 58% of participants. Optical coherence tomography showed optic nerve hypoplasia with associated foveal hypoplasia in four participants. In the remaining achiasmia participants, macular changes with significantly thinner paracentral inner segment (P = 0.002), wider pit (P = 0.04) and visual flattening of the ellipsoid line were found. MRI demonstrated chiasmatic aplasia in 3/12 (25%), chiasmatic hypoplasia in 7/12 (58%) and a subjectively normal chiasm in 2/12 (17%). Septo-optic dysplasia and severe bilateral optic nerve hypoplasia were found in three patients with chiasmic aplasia/hypoplasia on MRI. In this largest series of achiasmia patients to date, we found for the first time that neuronal abnormalities occur already at the retinal level. Foveal changes, optic nerve hypoplasia and the midline brain anomaly suggest that these abnormalities could be part of the same spectrum, with different manifestations of events during foetal development occurring with varying severity.
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Affiliation(s)
- Anastasia Pilat
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Rebecca J McLean
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | | | - Robert A Dineen
- Division of Clinical Neuroscience, Queen’s Medical Centre, Radiological Sciences, University of Nottingham, Nottingham, UK
- NIHR Nottingham Biomedical Research Centre, Queen’s Medical Centre, University of Nottingham, Nottingham, UK
| | - Irene Gottlob
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
- Department of Neurology, Cooper University Hospital, Cooper Neurological Institute, Camden, USA
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Kuht HJ, Thomas MG, McLean RJ, Sheth V, Proudlock FA, Gottlob I. Abnormal foveal morphology in carriers of oculocutaneous albinism. Br J Ophthalmol 2023; 107:1202-1208. [PMID: 35379600 PMCID: PMC10359511 DOI: 10.1136/bjophthalmol-2020-318192] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 03/18/2022] [Indexed: 01/04/2023]
Abstract
BACKGROUND/AIMS To investigate the foveal morphology in carriers of oculocutaneous albinism (OCA) using spectral domain optical coherence tomography (SD-OCT). A cross-sectional, observational study. METHODS Handheld SD-OCT (Envisu C2300) was used to acquire horizontal scans through the centre of the fovea in biological parents of patients with OCA (n=28; mean age±SD=40.43±8.07 years) and age-matched and ethnicity-matched controls (n=28; mean age±SD=38.04±10.27 years). Sequence analysis was performed for variants in known genes associated with OCA. Best-corrected visual acuity (BCVA), presence of foveal hypoplasia and grade, foveal, parafoveal and perifoveal thickness measurements of total retinal layers (TRL), inner retinal layers (IRL) and outer retinal layers (ORL) thickness were measured. RESULTS Foveal hypoplasia was identified in 32.14% of OCA carriers; grade 1 in all cases. OCA carriers demonstrated significant thicker TRL thickness (median difference: 13.46 µm, p=0.009) and IRL thickness (mean difference: 8.98 µm, p<0.001) at the central fovea compared with controls. BCVA of carriers was between -0.16 and 0.18 logMAR (mean: 0.0 logMAR). No significant differences in BCVA was noted between OCA carriers or controls (p=0.83). In the OCA carriers, we identified previously reported pathogenic variants in TYR, OCA2 and SLC45A2, novel OCA2 variants (n=3) and heterozygosity of the pathogenic TYR haplotype. CONCLUSION We have, for the first time, identified foveal abnormalities in OCA carriers. This provides clinical value, particularly in cases where limited phenotype data are available. Our findings raise the possibility that previously reported mild cases of foveal hypoplasia or isolated foveal hypoplasia could correspond to OCA carrier status.
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Affiliation(s)
- Helen J Kuht
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Mervyn G Thomas
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Rebecca J McLean
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Viral Sheth
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Frank A Proudlock
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
| | - Irene Gottlob
- Ulverscroft Eye Unit, Neuroscience, Psychology and Behaviour, University of Leicester, Leicester, UK
- Cooper Medical School of Rowan University, Cooper Neurological Institute, Camden, New Jersey, USA
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The retinal pigmentation pathway in human albinism: Not so black and white. Prog Retin Eye Res 2022; 91:101091. [PMID: 35729001 DOI: 10.1016/j.preteyeres.2022.101091] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 12/16/2022]
Abstract
Albinism is a pigment disorder affecting eye, skin and/or hair. Patients usually have decreased melanin in affected tissues and suffer from severe visual abnormalities, including foveal hypoplasia and chiasmal misrouting. Combining our data with those of the literature, we propose a single functional genetic retinal signalling pathway that includes all 22 currently known human albinism disease genes. We hypothesise that defects affecting the genesis or function of different intra-cellular organelles, including melanosomes, cause syndromic forms of albinism (Hermansky-Pudlak (HPS) and Chediak-Higashi syndrome (CHS)). We put forward that specific melanosome impairments cause different forms of oculocutaneous albinism (OCA1-8). Further, we incorporate GPR143 that has been implicated in ocular albinism (OA1), characterised by a phenotype limited to the eye. Finally, we include the SLC38A8-associated disorder FHONDA that causes an even more restricted "albinism-related" ocular phenotype with foveal hypoplasia and chiasmal misrouting but without pigmentation defects. We propose the following retinal pigmentation pathway, with increasingly specific genetic and cellular defects causing an increasingly specific ocular phenotype: (HPS1-11/CHS: syndromic forms of albinism)-(OCA1-8: OCA)-(GPR143: OA1)-(SLC38A8: FHONDA). Beyond disease genes involvement, we also evaluate a range of (candidate) regulatory and signalling mechanisms affecting the activity of the pathway in retinal development, retinal pigmentation and albinism. We further suggest that the proposed pigmentation pathway is also involved in other retinal disorders, such as age-related macular degeneration. The hypotheses put forward in this report provide a framework for further systematic studies in albinism and melanin pigmentation disorders.
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Al-Nosairy KO, Quanz EV, Biermann J, Hoffmann MB. Optical Coherence Tomography as a Biomarker for Differential Diagnostics in Nystagmus: Ganglion Cell Layer Thickness Ratio. J Clin Med 2022; 11:jcm11174941. [PMID: 36078871 PMCID: PMC9456294 DOI: 10.3390/jcm11174941] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/12/2022] [Accepted: 08/13/2022] [Indexed: 11/25/2022] Open
Abstract
In albinism, with the use of optical coherence tomography (OCT), a thinning of the macular ganglion cell layer was recently reported. As a consequence, the relevant OCT measure, i.e., a reduction of the temporal/nasal ganglion cell layer thickness quotient (GCLTQ), is a strong candidate for a novel biomarker of albinism. However, nystagmus is a common trait in albinism and is known as a potential confound of imaging techniques. Therefore, there is a need to determine the impact of nystagmus without albinism on the GCLTQ. In this bi-center study, the retinal GCLTQ was determined (OCT Spectralis, Heidelberg Engineering, Heidelberg, Germany) for healthy controls (n = 5, 10 eyes) vs. participants with nystagmus and albinism (Nalbinism, n = 8, 15 eyes), and with nystagmus of other origins (Nother, n = 11, 17 eyes). Macular OCT with 25 horizontal B scans 20 × 20° with 9 automated real time tracking (ART) frames centered on the retina was obtained for each group. From the sectoral GCLTs of the early treatment diabetic retinopathy study (ETDRS) circular thickness maps, i.e., 3 mm and 6 mm ETDRS rings, GCLTQ I and GCLTQ II were determined. Both GCLTQs were reduced in Nalbinism (GCLTQ I and II: 0.78 and 0.77, p < 0.001) compared to Nother (0.91 and 0.93) and healthy controls (0.89 and 0.95). The discrimination of Nalbinism from Nother via GCLTQ I and II had an area under the curve of 80 and 82% with an optimal cutoff point of 0.86 and 0.88, respectively. In conclusion, lower GCLTQ in Nalbinism appears as a distinguished feature in albinism-related nystagmus as opposed to other causes of nystagmus.
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Affiliation(s)
- Khaldoon O. Al-Nosairy
- Department of Ophthalmology, Faculty of Medicine, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Elisabeth V. Quanz
- Department of Ophthalmology, Faculty of Medicine, Otto-von-Guericke University, 39120 Magdeburg, Germany
| | - Julia Biermann
- Department of Ophthalmology, University of Muenster Medical Centre, 48149 Muenster, Germany
| | - Michael B. Hoffmann
- Department of Ophthalmology, Faculty of Medicine, Otto-von-Guericke University, 39120 Magdeburg, Germany
- Center for Behavioral Brain Sciences, 39118 Magdeburg, Germany
- Correspondence:
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Sobolev NP, Teplovodskaya VV, Sudakova EP. [Method of surgical treatment of patients with oculocutaneous albinism using artificial iris]. Vestn Oftalmol 2022; 138:58-63. [PMID: 35234422 DOI: 10.17116/oftalma202213801158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Oculocutaneous albinism is a group of autosomal recessive disorders that directly affect the hypopigmentation of the skin, hair, and eyes. According to the World Health Organization, albinism occurs in 1 out of 20 000 people in Europe and North America. Congenital changes in the organ of vision in albinism lead to a significant decrease in the visual functions of patients, worsening their quality of life. PURPOSE To study the results of surgical treatment with implantation of an artificial iris as a diaphragm element in patients with albinism. MATERIAL AND METHODS This article was based on the examination and treatment of 2 patients suffering from oculocutaneous albinism, which is characterized by hypopigmentation of the iris and retinal pigment epithelium of the retina, foveolar hypoplasia, low visual acuity, nystagmus, strabismus and excruciating photophobia. The patients were implanted an artificial iris in both eyes with fixation in the capsular bag in the first patient, and in the ciliary sulcus in the second. RESULTS In both patients, complaints of photophobia and optical phenomena have ceased. Visual acuity increased to 0.2 and remained without regression throughout the entire period of observation. Intraocular pressure and hydrodynamic parameters also remained stable throughout the observation period. The artificial irises were observed by ultrabiomicroscopy to remain in a stable position both when it was implanted in the capsule bag, and when it was seamlessly fixed in the ciliary sulcus. CONCLUSION The surgical interventions relieved patients from glare, at the same time improving visual acuity without correction, as well as achieving a pronounced cosmetic effect and visual rehabilitation. Artificial irises have proven to be a safe and effective way to treat patients with oculocutaneous albinism.
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Affiliation(s)
- N P Sobolev
- S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Moscow, Russia
| | - V V Teplovodskaya
- S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Moscow, Russia
| | - E P Sudakova
- S.N. Fedorov National Medical Research Center «MNTK «Eye Microsurgery», Moscow, Russia
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Muns SM, Villegas VM, Schwartz SG. Clinical spectrum of blunted foveal contour. Ther Adv Ophthalmol 2022; 14:25158414211070864. [PMID: 35083420 PMCID: PMC8785340 DOI: 10.1177/25158414211070864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 12/13/2021] [Indexed: 11/15/2022] Open
Abstract
Foveal hypoplasia is the absence of a foveal depression and the presence of the ganglion cell layer in the foveola. A spectrum of clinical characteristics, including normal or variably decreased visual acuity, has been described in patients with blunted foveal contours. Multiple systemic and ophthalmologic conditions including albinism, aniridia, nanophthalmos, prematurity, and fovea plana have been associated with this anomaly. This article illustrates select clinical conditions characterized by a blunted foveal contour. Given the heterogeneity of findings, a thorough medical history and detailed physical and ocular examinations are usually sufficient for the clinician to make the correct diagnosis.
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Affiliation(s)
- Sofía M. Muns
- School of Medicine, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
| | - Victor M. Villegas
- School of Medicine, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
- Department of Ophthalmology, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico
- Department of Ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, Miami, FL, USA
- Department of Surgery, Ponce Health Sciences University, Ponce, Puerto Rico
| | - Stephen G. Schwartz
- Department of Ophthalmology, Bascom Palmer Eye Institute, Miller School of Medicine, University of Miami, 3880 Tamiami Trail North, Naples, FL 34103, USA
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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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Woertz EN, Omoba BS, Dunn TM, Chiu SJ, Farsiu S, Strul S, Summers CG, Drack AV, Carroll J. Assessing Ganglion Cell Layer Topography in Human Albinism Using Optical Coherence Tomography. Invest Ophthalmol Vis Sci 2020; 61:36. [PMID: 32196097 PMCID: PMC7405956 DOI: 10.1167/iovs.61.3.36] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Purpose To test whether ganglion cell layer (GCL) and inner plexiform layer (IPL) topography is altered in albinism. Methods Optical coherence tomography scans were analyzed in 30 participants with albinism and 25 control participants. Horizontal and vertical line scans were acquired at the fovea, then strip registered and averaged. The Duke Optical Coherence Tomography Retinal Analysis Program was used to automatically segment the combined GCL and IPL and total retinal thickness, followed by program-assisted manual segmentation of the boundary between the GCL and IPL. Layer thickness and area under the curve (AUC) were calculated within 2.5 mm of the fovea. Nasal-temporal and superior-inferior asymmetry were calculated as an AUC ratio in each quadrant. Results GCL and IPL topography varied between participants. The summed AUC in all quadrants was similar between groups for both the GCL (P = 0.84) and IPL (P = 0.08). Both groups showed nasal-temporal asymmetry in the GCL, but only participants with albinism had nasal-temporal asymmetry in the IPL. Nasal-temporal asymmetry was greater in albinism for both the GCL (P < 0.0001) and the IPL (P = 0.0006). The GCL usually comprised a greater percentage of the combined GCL and IPL in controls than in albinism. Conclusions The GCL and IPL have greater structural variability than previously reported. GCL and IPL topography are significantly altered in albinism, which suggests differences in the spatial distribution of retinal ganglion cells. This finding provides insight into foveal development and structure-function relationships in foveal hypoplasia.
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