Progressive retinal atrophy / rcd3-PRA (PDE6A-related) - Dog

What does this test examine?

This genetic test analyses the PDE6A c.1940delA variant in susceptible breeds such as Cardigan Welsh Corgi, Pembroke Welsh Corgi, Chinese Crested and Pomeranian. The condition is known as progressive retinal atrophy / rcd3-PRA and is also referred to as PRA, rcd3, rcd3-PRA, rod-cone dysplasia 3 and PRA-PDE6A. The result shows whether the dog carries zero, one or two copies of the tested variant.

PDE6A is important for normal photoreceptor function in the retina. When both gene copies carry the tested variant, this causes an inherited form of retinal degeneration with progressive loss of vision.

What does this condition mean?

rcd3-PRA is an early-onset form of PRA. Affected dogs can lose vision at a young age; in Corgi lines, signs may already become visible during puppyhood.

In progressive retinal atrophy, the light-sensitive retinal cells lose function. Dogs may first show reduced vision in dim light or bright light, become less confident in unfamiliar surroundings, bump into objects and eventually become severely visually impaired or blind.

Inheritance and result

The trait is inherited in an autosomal recessive way. A clear dog does not carry the variant. A carrier has one copy and is usually not affected, but can pass the variant to offspring. A dog with two copies has the affected genotype for this test.

• N/N - no copy of the tested variant detected.
• N/delA - carrier: one copy of the tested variant detected.
• delA/delA - affected genotype: two copies of the tested variant detected.

Practical value of this test

This DNA test is useful because carriers can look completely normal. Breeders can use the result to plan matings more precisely, manage carriers responsibly and strongly reduce the risk of puppies affected by inherited retinal degeneration.

The result also makes eye health easier to manage within a breeding programme: it can support puppy selection, breeding-animal evaluation, comparison of possible mates and long-term planning across generations. Because several breeds can use the same test, correct breed context is important for interpretation.