Abstract
Purpose :
There are currently over 90 genes associated with the development of retinitis pigmentosa (RP), an inherited retinal disorder affecting approximately 1 in 3000-5000 people worldwide. Previous research has demonstrated variability in disease severity and rates of disease progression between separate subtypes of RP, but research concerning possible imaging biomarkers that can differentiate between distinct genotypes of RP is limited. Our aim was to use fundus autofluorescence (FAF) imaging in order to examine whether patterns of autofluorescence (AF) differed in a heterogenous group of RP patients.
Methods :
We used the NIH EyeGene database to compile FAF images of 31 patients with RP that met our exclusionary criteria. These patients had pathogenic mutations spanning 11 RP-associated genes, including HK1, IMPDH1, KLHL7, NR2E3, PRPF31, RP1, RP2, USH2A, RPGR, RHO, and PRPH2. The FAF images were reviewed for patterns of autofluorescence and qualitative observations were recorded.
Results :
Eight patterns of fundus autofluorescence were identified in the RP patients included in the study. Four of these patterns were found within the macula, including a bull’s eye pattern of AF, central foveal hyper AF, a perifoveal hyper AF ring, and a macular hyper AF ring. The remaining four patterns were extramacular and included a mid-peripheral hyper AF ring, extramacular spots of hyper AF, patches of hypo AF and diffuse hypo AF in the periphery. A double concentric hyper AF ring was present in 4 of the 11 RP-subtypes studied (RHO, RPGR, USH2A, NR2E3). To our knowledge this is the first report of a double concentric ring of hyper AF in RPGR-linked RP
Conclusions :
Of the genes studied, there were no highly-penetrant patterns that were unique to a single subtype of RP, suggesting there may be significant phenotypic overlapping between RP subtypes on FAF imaging. The double concentric hyper AF ring is less specific than previously thought.
This is a 2021 ARVO Annual Meeting abstract.