Purpose
To report molecular genetic testing results, OCT findings and FAF patterns in three patients with PRPD.
Methods
Three patients aged 44 to 76 years with reduced ERGs having RPE atrophy and bone-spicule pigmentation radiating from the disc and along the superior and inferior arcades were studied. Patient #1 was symptomatic for night blindness. Patient #2 denied night blindness and had CSME secondary to non-proliferative diabetic retinopathy treated by focal laser. Patient #3 was symptomatic for night blindness and had chronic CME. Genetic testing of the combined genes known to be associated with 40% of autosomal dominant retinitis pigmentosa (adRP) was performed by a commercial laboratory. For Patient #1 tested 3 years ago, the entire coding regions of the RHO and RDS genes and a portion of the RP1 gene and a portion of the C1QTNF5 gene were screened for sequence variation using a combination of single-strand conformation polymorphism (SSCP) analysis and automated sequencing. For patients #2 and #3, tested in 2013, DNA was screened using an allele specific assay of 45 of the most common adRP-causing variations in 13 genes. If a negative result occurred, the DNA was directly sequenced through portions of the RDS, RHO and TOPORS genes. OCT of the posterior pole was performed using the Topcon SD- OCT (3D-2000, Topcon, Inc., Oakland, NJ). FAF was performed using the Daytona camera (Optos, Inc., Boston MA.)
Results
Four non-disease causing variations in RDS were found in Patient#1. Patient #2 had one non-disease causing variation in RDS. Patient #3 had two non-disease causing variations, one in RHO and one in RDS. On OCT, the photoreceptor integrity line (IS/OS line; ellipsoid) was missing throughout the posterior pole except at the macula in Patient #1 and including the macula in Patient #2 and Patient #3. The FAF patterns of all 3 patients demonstrated hypoAF around the optic disc and along the arcades and a perimacular hyperAF ring typical of retinal photoreceptor degeneration (Figures).
Conclusions
Genetic testing did not reveal any adRP disease causing sequence variations in the genes tested and known to be associated with 40% of adRP. OCT and FAF may be more diagnostic, along with the clinical picture and other testing results, than genetic testing, since the majority of adRP patients do not exhibit a change in the currently tested genes.
Keywords: 696 retinal degenerations: hereditary •
537 gene screening •
550 imaging/image analysis: clinical