Variabilities in retinal function and structure in a canine model of cone-rod dystrophy associated with RPGRIP1 support multigenic etiology.
Defects in cilia gene RPGRIP1 causes Leber congenital amaurosis and cone-rod dystrophy in humans. A form of the cone rod dystrophy dog (cord1) was originally associated with the insertion of homozygotes in RPGRIP1 (RPGRIP1 in / in) as the major disease locus while homozygous deletion in MAP9 (MAP9 del / del) was identified as a modifier associated with early onset form. However, we find more variability in Electroretinograms cone (ERGs) ranging from normal to absent in the extended RPGRIP1 ins / ins colony of dogs, regardless Zebrafish Clia Kits of genotype MAP9. Ophthalmoscopically, cone ERGabsent RPGRIP1 ins / ins eyes showing discoloration of the tapetal fundus with a variety of disease onset and development, while sd-OCT revealed atrophic changes. Despite a marked change in the cone ERG and retinal morphology, behavior photopic vision-guided comparable between the normal and the cones ERGabsent RPGRIP1 ins / ins littermates. Cone morphology less dog cone ERG cut with...