Genetic Test Available: BULLMASTIFF
Progressive Retinal Atrophy (PRA) (Form: Dominant)
Breed(s): Bullmastiff, English Mastiff, Mastiff Disease: Progressive Retinal Atrophy
Laboratory: Genetic Technologies (Australia), Optigen LLC
Progressive Retinal Atrophy (PRA):
An Overview Progressive Retinal Atrophy, or PRA, is a condition of the retina in the eye. PRA encompasses many diseases which all progress over time and eventually lead to blindness. The retina works in the eye much as the film in a camera works. It changes the light it receives into images which are then sent down the optic nerve to be interpreted by the brain. When a dog has PRA the retina either stops developing prematurely or the light receptors degenerate early in life. With this condition both eyes are equally affected. The different forms of PRA vary in the age at which they first develop and in the rate at which they progress. Cases can be early onset with rapid progression to late onset with slow progression or any combination of the sorts. Every case is different and definite age of onset or how quickly progression will occur can never be known for sure. Since PRA has been identified, numerous dog breeds have been found to have the disease. Some breeds that PRA is commonly found in are Irish Setters, Rough Collies, Miniature and Toy Poodles, Labrador Retrievers, English Cocker Spaniels, American Cocker Spaniels, Portuguese Water Dogs, Chesapeake Bay Retrievers, Australian Cattle Dogs, Nova Scotia Duck Tolling Retrievers, Siberian Huskies, and Samoyeds.
Causes of Progressive Retinal Atrophy
PRA is an inherited disorder. This means it is passed down from parents to offspring. In many breeds there is now a test which can be done that allows breeders and owners to know if a dog is clear of the disease, a carrier of the disease, or affected by the disease.
Symptoms of Progressive Retinal Atrophy
PRA over time will lead to blindness. The first sign of this disease is typically night blindness. Owners may observe their dog being hesitant to walk down dark hallways or staircases, or be less likely to go outside at night. As PRA progresses daytime vision will also be lost. In addition to these symptoms pupil dilation, or enlargement, is seen due to the eye attempting to let in more light along with an increase in the amount of light reflected back off the eye. In some cases cataracts may appear but are not the cause of the blindness. There is no pain associated with PRA and dogs seem to adjust very well to their blindness. In some cases owners may not even realize the dog is having problems seeing until they are taken out of their home environment.
Diagnosing Progressive Retinal Atrophy
PRA is diagnosed by an eye examination by a veterinarian. There are certain changes which can be seen in the eye characteristic of PRA. In addition to an eye exam an electroretinography may be done to obtain a diagnosis. An electroretinography measures the electrical responses in the retina to determine if it is functioning properly.
Treating Progressive Retinal Atrophy
There is currently no treatment for PRA. To help breeders prevent PRA there are genetic tests available which can identify dogs which are affected, carries, or clear of the disease. This is extremely helpful due to the face that in many cases PRA does not appear until the dog is older (5-7 years). By this time the dog has already been bred. With the genetic tests breeders can know right away if a dog should be used in their breeding program or not. The PRA genetic tests are available for certain dog breeds though OptiGen. For more information about PRA contact your local veterinarian.
Care for Dogs with Progressive Retinal Atrophy
Blindness is the eventual result of PRA. Because the blindness does not occur quickly dogs have time to adjust to not being able to see well. Dogs that are blind can still live normal happy lives. There are certain things you as an owner can do to help your pet adjust. One of these is keeping your furniture in the same place. Your dog will become accustomed to the layout of your house. If you move furniture it may cause them to run into chairs or tables because they are not used to them being in that place. Another thing you can do is to keep floors and walkways clear of clutter. This will prevent your dog from tripping over objects. When introducing your dog to a new area always leash walk them around first so they can get a feel for the area and learn the boundaries. All of these will help your dog adjust to their vision loss.
The AKC Canine Health Foundation and Progressive Retinal Atrophy
The AKC Canine Health Foundation has funded 8 research projects focused on PRA. The grants, totally over $650,000, have been researching the genetic marker which is associated with the disease. This research has led to genetic tests being made available to breeders. With your continued support research can continue for breeds which do not currently have a genetic test for PRA.