Abstract
Purpose :
To analyze data of patients with retinitis punctata albescens (RPA) caused by mutations in RLBP1 in the aim of a gene therapy.
Methods :
Database of a national center in rare diseases specialized in inherited retinal disease (3680 families) were screened for patients with RPA and mutations in RLBP1. Visual acuity, kinetic visual field, color and autofluorescent imaging, ISCEV full field electroretinogramm were reviewed. Correlations between visual data and age were investigated with the Pearson’s linear coefficient.
Results :
13 families (19 patients) were included. Eleven patients from 7 Morocco families were all homozygous for the recurrent RLBP1 deletion of exons 7-9. Two novel RLBP1 mutations were found: i. a Tyr111Stop mutation, located in exon 5, probably causes the activation of the mRNA decay mechanism and therefore is a null allele, ii. An Arg9Cys mutation is predicted to be damaging and was never reported in databases, while an Arg9His change has been found in 2/12996 cases of the exome variant server database. Night blindness was noted in early childhood between 2 and 6 years of age in all patients. The typical white dot-like deposits were not constant in late stages (2 patients), Visual acuity (1.2 to counting fingers) was not correlated with age (p=0.2673) and foveal thickness (p=0.489). The retinal thickness at 3-mm and 6-mm rings significantly decreased with age (p<0.01 for both rings and all quadrants), the temporal side was the most affected quadrant. There was no correlation between age and visual field (p=0.0812). Although there was a tendency to decrease with age, no significant correlation between age and amplitude of 30-Hz flickers was evidenced (p=0.0632).
Conclusions :
In conclusion, some parameters of the disease progression like visual acuity, peripheral visual field and cone ERG, were not correlated with age. Typical white dot-like lesions were not constant or difficult to identify especially in late stages suggesting that RPA could be misdiagnosed. This last point should be considered to identify patients for which RLBP1 therapy could be indicated.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.