Progressive retinal atrophy (rcd3) testing

Progressive retinal atrophy is a hereditary eye condition that cannot be prevented or cured, and that ultimately leads to a slow and progressive blindness in affected dogs. Progressive retinal atrophy comes in a wide variety of different forms and types, each of which are caused by a different gene mutation, and whilst they all lead to blindness, the way that they work and their prevalence across different breeds of dog can be very variable.

The rcd3 form of progressive retinal atrophy is just one of the many variants of the condition, and this form of the disease is most prevalent in the Cardigan Welsh Corgi and the Tibetan terrier dog breeds-and this is the form of the condition that we will discuss in this article.

Read on to learn more about the rcd3 form of progressive retinal atrophy, how it affects dogs, and how and why it can be tested for.

What is rcd3 progressive retinal atrophy?

The rcd3 variant of progressive retinal atrophy is one of the rod-cone affective forms of the condition, with the “3” designation referring to a further divergence in terms of the various different strains of this type of the condition.

Rcd3 causes the rods and cones at the back of the retina-the area responsible for receiving light and colour and transmitting it to the brain, where it is interpreted into a picture of vision-to deteriorate and break down without being renewed, which leads to the slow, progressive and irreversible blindness that is the signature of all forms of progressive retinal atrophy.

What sort of dogs are affected by it?

The rcd3 variant of progressive retinal atrophy is almost exclusively found in the Cardigan Welsh Corgi and the Tibetan terrier dog breeds, and of course, any cross-breed or mongrel dogs that have one of these two breeds in their ancestry.

Progressive retinal atrophy as a whole rarely begins to manifest in dogs under the age of three-but in the Cardigan Welsh Corgi, the rcd3 variant is often faster in onset, and signs may become apparent from as early as six weeks of age, and is usually evident by the time the dog reaches their second birthday.

How would I know if my dog was developing it?

Dogs and puppies that inherit the genetic markers for the condition will be born with apparently healthy, normal eyes and vision.

The first indications of the condition that you are likely to notice are a gradual failing of your dog’s vision, which will usually be more apparent at night and in dim light, progressing to affecting the dog in even bright light, as it ultimately causes total blindness.

If your dog is one of the two breeds known to be affected by the condition, or if they have any relatives with the condition, testing is the only sure-fire way to know if they have inherited the condition before symptoms become apparent, and so, let you know what to expect.

If you own a Cardigan Welsh Corgi or a Tibetan terrier that you intend to use for breeding, it is important to have them tested for the condition, to find out if they either have PRA rcd3 themselves, or are carriers for it.

Carrier dogs will not suffer from the condition themselves, but will pass it onto their offspring, and so it is important to know this before making the decision to breed.

How does the condition’s heredity work?

PRA rcd3 is an autosomal recessive condition, which means that in order for a dog to be affected with it, they must inherit two copies of the faulty rcd3 gene that causes the condition-one from each of their two parent dogs.

If neither parent dog passes on the gene, the dog in question will neither develop the condition nor become a carrier for it-but if one of the parent dogs passes on the gene but the other does not, their subsequent offspring will carry the condition and run the risk of passing it on to their own potential offspring.

What does the test involve?

Pre-breeding testing is really important for the two breeds that are considered to be at risk for the condition because of its prevalence within the gene pool, in order to ensure that rcd3 is not spread any further, and does not go on to affect ever-more future litters of dogs.

A simple DNA test is all that is required to identify the markers of the condition and find out if a dog carries the condition or is going to develop it, and in order to perform the test, you will need to send off a sample of your dog’s DNA to one of the various laboratories that offer a testing service.

A cheek swab will be taken by your vet, which is then sent off for assessment, and the results returned to you. For more details about the laboratories that offer the rcd3 PRA test in the UK, check out the list on The Kennel Club’s website.