Part of the official UK Kennel Club testing scheme in Dachshund (Miniature Long Haired), Dachshund (Miniature Smooth Haired), Dachshund (Miniature Wire Haired) and Spaniel (English Springer)
Progressive retinal atrophy (PRA) is the most common form of inherited disease affecting the retina in dogs. Genetically different forms of PRA, caused by mutations in different genes, affect many breeds of dog with each form usually affecting one or a small number of breeds. PRA is characterised by progressive degeneration of the retina at the back of the eye and leads to vision loss and blindness.
In most knowns forms of PRA the rod cells of the retina degenerate first, resulting in a loss of dim light vision initially. In this specific form of PRA the cone cells of the retina degenerate first, followed by the rod cells (cone rod dystrophy), so dogs affected with CORD1 do not develop night blindless first. As with all dogs suffering from PRA, there is no cure. Dogs generally adapt quite well to blindness – especially when it develops gradually – as long as their surroundings remain familiar (e.g. furniture does not get rearranged, they do not move house etc).
The age of onset of CORD1 is highly variable. Dogs the are also homozygous for the MAP9 modifier mutation will develop the disease from a young age (< 3 years old). On the other hand, dogs that are homozygous for the CORD1-RPGRIP1 variant but not the MAP9 variant may develop the disease later in life (> 6 years old).