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Photoreceptor Structure in GNAT2-Associated Achromatopsia

Georgiou, M; Singh, N; Kane, T; Robson, AG; Kalitzeos, A; Hirji, N; Webster, AR; ... Michaelides, M; + view all (2020) Photoreceptor Structure in GNAT2-Associated Achromatopsia. Investigative Ophthalmology & Visual Science , 61 (3) , Article 40. 10.1167/iovs.61.3.40. Green open access

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Abstract

Purpose: The purpose of this study was to report GNAT2-associated achromatopsia (GNAT2-ACHM) natural history, characterize photoreceptor mosaic, and determine a therapeutic window for potential intervention. Methods: Patients with GNAT2-ACHM were recruited from a single tertiary referral eye center (Moorfields Eye Hospital, London, UK). We performed longitudinal clinical evaluation and ophthalmic examination, and multimodal retinal imaging, including adaptive optics scanning light ophthalmoscopy, quantitative analysis of the cone mosaic, and outer nuclear layer (ONL) thickness, including cone densities evaluation in selected regions of interest and comparison with reported healthy controls. Results: All nine subjects (3 women) presented with nystagmus, decreased visual acuity (VA), light sensitivity, and highly variable color vision loss. One patient had normal color vision and better VA. Mean VA was 1.01 (±0.10) logarithms of the minimal angle of resolution (LogMAR) at baseline, and 1.04 (±0.10) LogMAR after a mean follow-up (range) of 7.6 years (1.7-12.8 years). Optical coherence tomography showed preservation of the foveal ellipsoid zone (EZ; n = 8; 88.9%), and EZ disruption (n = 1; 11.1%). Mean ONL thickness (range, ± SD) was 84.72 µm (28.57-113.33, ± 25.46 µm) and 86.47 µm (28.57-113.33, ± 24.65 µm) for right and left eyes, respectively. Mean cone densities (±SD) at 190 µm, 350 µm, and 500 µm from the foveal center, were 48.4 (±24.6), 37.8 (±14.7), and 30.7 (±9.9), ×103 cones/mm2, respectively. Mean cone densities were lower than these of unaffected individuals, but with an overlap. Conclusions: The cone mosaic in GNAT2-ACHM is relatively well preserved, potentially allowing for a wide therapeutic window for cone-directed interventions.

Type: Article
Title: Photoreceptor Structure in GNAT2-Associated Achromatopsia
Location: United States
Open access status: An open access version is available from UCL Discovery
DOI: 10.1167/iovs.61.3.40
Publisher version: http://dx.doi.org/10.1167/iovs.61.3.40
Language: English
Additional information: This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.
Keywords: adaptive optics, retinal phenotyping, inherited retinal diseases, genetics, GNAT2, achromatopsia
UCL classification: UCL
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Brain Sciences > Institute of Ophthalmology
URI: https://discovery-pp.ucl.ac.uk/id/eprint/10094249
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