Part of the official UK Kennel Club testing scheme in Shetland Sheepdog
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.
This specific form of PRA is caused by a mutation in a gene called CNGA1 and is indistinguishable from other forms of PRA in other breeds. The average age of onset of clinical signs is around 5 years, but can be anything between 2 and 11 years. In humans, mutations in CNGA1 are associated with a condition known as Retinitis Pigmentosa, symptoms of which include loss of peripheral vision and the ability to see at night. There is no cure for this form of PRA, but using the DNA test to identify dogs that carry the mutation in CNGA1 will prevent further spread of this blinding condition in this lovely breed.