A Natural History Study of RP2-Related Retinopathy

Abstract

X-linked retinitis pigmentosa (RP) is a severe form of RP, often with early macular involvement. This study aimed to characterise the natural history of patients with a diagnosis of X-linked RP due to RP2 mutations. Clinical details, best-corrected visual acuity (BCVA) and multimodal retinal imaging were retrospectively collected from patients with RP2 variants from Moorfields Eye Hospital (London, UK). Measures of the ellipsoid-zone (EZ) width, central retinal thickness (CRT), and thickness of the photoreceptor and retinal pigment epithelium complex (PR+RPE, taken between the external limiting membrane and RPE) were extracted from spectral-domain optical coherence tomography (SD-OCT) scans. A total of 47 affected males (median baseline age: 20 years, IQR: 12.5–36.5) were included, and 41 had two or more visits (median follow-up: 8.0 years, IQR: 3.2–14.5). A total of 24 RP2 variants were identified, 13 of which were novel. BCVA dropped from 0.66 LogMAR at baseline (IQR, 0.35–1.4) to 1.3 LogMAR at the most recent visit (IQR: 0.6–1.4). SD-OCT revealed a prevalent outer retinal atrophy (n = 23/35, 65.7%), and measurable EZ width at baseline in 34.3% of patients (n = 12). Age significantly affected all quantitative measures (p < 0.001) except EZ width (p = 0.58), with exponential decays of 46–49% and 12.6–33.9% per decade for BCVA and SD-OCT measures, respectively. RP2 patients exhibited rapid progression to outer retina atrophy and early macular involvement with substantial vision loss by age 30–40.

Prevalence and Clinical Features of Radial Fundus Autofluorescence in High Myopic Women

“…A disruption of ellipsoid zones was also found in OCT images in RP2 retinopathy. 24 The interdigitation zone could not be identified clearly in the OCT images in all 15 of our patients. However, it was also difficult to identify the interdigital zones in the OCT images in highly myopic eyes because of poor image quality and distorted retinal structures.…”

Longitudinal structure-function analysis of molecularly-confirmed CYP4V2 Bietti Crystalline Dystrophy

“…Retinal and choroidal thicknesses were measured manually using Spectralis’ inbuilt measuring tool. For greater consistency we considered thickness as the vertical distance between retinal layers of interest at the fovea [ 24 , 25 ]. Central retinal thickness (CRT) was measured between the inner limiting membrane and the RPE.…”

“…Central retinal thickness (CRT) was measured between the inner limiting membrane and the RPE. Thickness of photoreceptor and RPE complex (PR + RPE) was taken between the external limiting membrane and the RPE [ 25 , 26 ]. Lastly, in patients with detectable choroid-scleral junction, choroidal thickness was measured between the posterior RPE border and anterior border of the sclera, visible as the outermost dark to bright transition from tubular choroidal texture to uniform scleral texture [ 27 – 29 ].…”

Longitudinal Changes of Retinal Structure in Molecularly Confirmed C1QTNF5 Patients With Late-Onset Retinal Degeneration

“…Central retinal thickness (CRT) considered the whole retina and was taken between inner limiting membrane and posterior border of the RPE-Bruch's membrane. We also extracted the thickness of the photoreceptor and RPE (PR+RPE) complex, 29 , 30 taken between external limiting membrane and the posterior border of the RPE-Bruch's membrane. For consistency across scans and to avoid mismatch between axial and lateral resolutions, we considered thickness as the vertical distance between retinal layers of interest at the fovea.…”