Abstract
Purpose:
Progressive rod-cone degeneration (PRCD) is a canine form of autosomal recessive photoreceptor degeneration and serves as an animal model for human retinitis pigmentosa (RP). To date only two RP-causing mutations of the PRCD gene have been reported in humans. We found a novel homozygous nonsense mutation in PRCD (c.52C>T, p.R18X) in three siblings affected by RP and present detailed morphologic and functional parameters.
Methods:
Complete ophthalmological examination was performed including psychophysical tests (ETDRS visual acuity, Lanthony Panel D-15 color vision test and visual field) and electrophysiology (Ganzfeld and multifocal ERG). Additionally, color and infrared fundus photography, autofluorescence and spectral domain optical coherence tomography (OCT) recordings were performed.
Results:
We identified a novel homozygous mutation in PRCD (c.52C>T, p.R18X) by diagnostic high-throughput panel sequencing. All three patients showed an advanced stage of disease with reduced visual acuity (mean VA: 20/80), small residual visual fields (mean VF for target III4e: 1134.35 deg2) and no recordable electrophysiological responses. Myopia, posterior subcapsular cataract, bone-spicule-like pigmentation and attenuated arterioles were typical findings. Interestingly, bulls eye maculopathy (BEM) due to patchy retinal pigment epithelium (RPE) atrophy was also present in all patients. The mean central retinal thickness (CRT) observed in OCT was 148µm.
Conclusions:
The identification of a third mutation in PRCD confirms its role in the pathogenesis of RP. Clinical findings were in line with the morphological changes observed in previous studies. BEM seems to be a hallmark for RP due to mutations in PRCD.
Keywords: 696 retinal degenerations: hereditary •
539 genetics •
507 electrophysiology: clinical