Progressive Retinal Atrophy (PRA) is a range of conditions, associated with the eyes, in which the retina degenerates leading to blindness. Usually, sight deteriorates from the age of three onwards, but in some dogs it can be much earlier than this and may even be before the dog leaves puppyhood. It is not present in all breeds of dog and thankfully, where it is known, there is a simple DNA test which can be undertaken to find if a dog is a carrier of the relevant gene.
Only one type of PRA is known within Entlebuchers and that is Progressive Rod-Cone Degeneration (prcd). It is an autosomal recessive gene, which means that for the condition to be expressed, the dog must inherit defective genes from both parents. This is good news for breeding as it means that as long as one of the parents is clear of the condition then there is no risk of any of their puppies developing the condition.
When dogs are tested they are referred to as ‘A’ ‘B’ or ‘C’. An ‘A’ is a dog who has two perfectly healthy copies of the gene and cannot pass the condition on to any pups.
A dog classified as ‘B’ is a carrier of the condition, meaning that one copy of the gene is affected and thus gives a 50% chance of passing the damaged gene on to puppies. In all responsible breeding programmes, a dog which is classified as ‘B’, and is therefore a carrier, should only ever be mated with a dog which is completely clear of the condition. This is the case for the EMDCGB breeding programme.
A dog classified as ‘C’ has copies of the gene which are both defective and will at some point in his life develop the condition. Dogs classified as ‘C’ will never be used for breeding by EMDCGB members.