Abstract
Purpose :
to characterize a large cohort of patients with RPGR-related rod-cone dystrophy (RCD) and compare the phenotypes of patients with mutations on the RPGR-ORF15 isoform and on the RPGR(1-19) isoform.
Methods :
male patients with RPGR-related RCD were recruited at the “Center of rare diseases” at “Quinze-Vingts” Hospital, Paris, France. Phenotypic data were collected retrospectively including age of onset, best corrected visual acuity (BCVA), presence of high myopia, kinetic visual field (VF), presence and size of a central hyper-reflective ring on short-wavelength fundus autofluorescence (SW-FAF), presence and width of central preserved ellipsoid zone (EZ) on optical coherence tomography (OCT). All available visits were considered for each patient and an estimation of the progression was done for each quantitative parameter through the analysis of the regression slopes which were then compared between the two genotypic groups. Finally, a correlation between BCVA and all other parameters was done using a linear regression analysis with the cross-sectional data from the last visit available.
Results :
28 patients (age: 42.73±22.27 years) with RPGR(1-19)-related RCD and 84 (age: 37.57±15.03 years) with mutations on the RPGR-ORF15 isoform were included. The age of onset was significantly earlier in the RPGR(1-19) group than the RPGR-ORF15 group (76.4% vs 50.8% in the 1st decade respectively). In both groups a progressive decline of all quantitative parameters was observed along the available follow-up (maximum 18 years for RPGR(1-19); maximum 14 years for RPGR-ORF15). When comparing the respective regression slopes for BCVA, VF, SW-FAF and OCT parameters, no significant differences were found between the two genotypic groups. In all the cohort (as well as in both RPGR(1-19) and RPGR-ORF15 cohorts separately), age was a strong predictor for BCVA (standardized β coefficient: 0.404, p<0.001) as well as the preserved EZ on OCT (standardized β coefficient: -0.450, p<0.001).
Conclusions :
longitudinal data on a large cohort of RPGR-related RCD showed no differences in progression between patients carrying mutations on different isoforms of the gene. Overall, the comprehensive analysis of RPGR(1-19)- and RPGR-ORF15-related RCD will help clinicians in assessing the visual prognosis of these patients. This will also constitute an important guidance in the design of therapeutic clinical trials.
This is a 2021 ARVO Annual Meeting abstract.