Abstract
Purpose: :
To determine if dogs heterozygous for both the PDE6A mutation that causes rod cone dysplasia type 3 and also for the PDE6B mutation that causes rod cone dysplasia type 1 have rod dysfunction or develop a retinal degeneration.
Methods: :
A PDE6A -/- bitch was bred to a PDE6B -/- male to produce PDE6A+/- PDE6B+/- puppies. Three PDE6A+/- /PDE6B+/- puppies were born. These were monitored by complete ophthalmic examinations, fundus photography, and electroretinography for 32 months. Full-field dark-adapted ERG intensity:response series and rod-mediated flicker responses were recorded followed by light adaptation and a light-adapted intensity:response series and cone flicker responses.
Results: :
No ophthalmoscopic evidence of retinal degeneration was observed over the time period. No significant abnormalities in rod-mediated ERGs were detected suggesting that the dogs had normal rod function. The ERG amplitudes remained comparable to those of wild-type dogs over the study period.
Conclusions: :
Dogs heterozygous for both the previously described PDE6A and the PDE6B null mutations do not appear to have abnormal retinal function and over the first 32 months of life show no evidence of retinal degeneration.
Keywords: retinal degenerations: hereditary • photoreceptors