Abstract
Purpose :
Mutations in PRPH2 are among the leading genetic causes of inherited retinal diseases (IRD). More than 200 different mutations in PRPH2 have been associated with multiple subtypes of IRD including retinitis pigmentosa and cone or macular diseases. The molecular mechanism associated with the mutation p.Pro210Arg (P210R) in PRPH2 has not been evaluated and little is known about the clinical presentation of patients with this particular genetic defect. The purpose of this research was to understand how this mutation affects visual function and retinal structure as well as gain insight into the mechanism driving the clinical features observed in these patients.
Methods :
Eleven patients from seven families had clinical assessments including best corrected visual acuity (BCVA), static (spot size V) perimetry (Octopus 900) and dark-adapted chromatic (DAC; Medmont; spot size V) perimetry. Images were acquired with the Optos ultra-wide field camera and spectral-domain optical coherence tomography (SD-OCT).
Results :
Patients who were previously determined to harbor the P210R mutation in PRPH2 had BCVA (Snellen) that ranged from 20/15 to 20/80. Perimetry exams showed an overall reduction in sensitivity. Scotomas were identified that corresponded to atrophic lesions on the retina. Imaging revealed drusen, hyper-fluorescent flecks, migrating RPE, interruptions in the inner/outer-segment junction, and foveal sparing.
Conclusions :
Rod and cone sensitivity was decreased in subjects with the P210R mutation in PRPH2. However absolute vision loss occurred within the macula and likely secondary to drusen formation. This suggests that although rod and cone photoreceptors are dependent on PRPH2, preventing blindness in this specific subgroup of patients should involve therapeutics to impede drusen formation.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.