Progressive Retinal Atrophy (PRA) is an eye disease of the dog, first described in 1907, in which the retina dies. Over time, PRA has been reported in several breeds of dogs. Is combated by various breeding strategies.
In Germany, in 2010, the club registered for the first time a single Gordon Setter who had PRA. Since the beginning of 2011, a DNA test has been available for the Gordon Setter breed that identifies a mutation in the genetic material (rcd4) that can trigger PRA.
This DNA test enables the breeders of the GSCD to plan the mating of parents in such a way that no Gordon Setter offspring can develop PRA (based on the rcd4 mutation).
What is PRA?
Progressive retinal atrophy (PRA) is a disease of the eye in which there is progressive death of the entire retina. The disease is hereditary, affects different breeds of dogs, is not treatable or curable and leads to total blindness of the affected animal.
The retina is a multi-layered structure in the back of the eye that uses photoreceptor cells (rods and cones) to convert light focused through the lens of the eye into electrical nerve signals in a series of chemical reactions. These signals are transmitted from the optic nerve to the brain. There converted to a perceptible image.
If the dog suffers from PRA, the rod cells first lose their normal function, which leads to progressive night blindness and loss of adaptation of vision to twilight. As the disease progresses, the cone cells, which are responsible for processing daylight, are destroyed and the affected dog becomes totally blind.
Clinical symptoms of the disease can appear already in the early youth of a dog. The owner first notices that the dog behaves normally in familiar surroundings, but walks more cautiously in unfamiliar surroundings and in darkness. In the further course the dog behaves more and more uncertainly and cautiously, whose cause lies in the worsened day vision. Noticeable are dilated pupils, which react badly or not at all to incident light. Often the lens of the eye becomes cloudy and opaque (cataract), which accelerates the blindness and complicates its course. The eyes are not painful.
The clinical diagnosis of PRA in dogs is made by a veterinary eye examination. The retina is examined with an ophthalmoscope (ophthalmological instrument) and shows typical changes. The diagnosis can be supported by an electroretinogram (ERG). Here electrical currents emanating from the retina are measured. This examination is performed under anesthesia. Should be done by specialized veterinarians.
Since PRA is neither curable nor treatable, but hereditary, it is important to identify those dogs that carry the predisposition for PRA in their genetic makeup. These dogs are u.U. do not have the disease themselves, but pass on PRA-causing genes to their offspring.
Commercial DNA tests are now available for many breeds of dogs. They determine from cellular material whether the dog carries PRA genes or is free. For the Gordon Setter exists since March 2011 in England a detection test, which makes it possible to identify Gordon Setters, which carry the genetic mutation (rcd4) and which cause a form of PRA.
Progressive Retinal Atrophy (PRA) is mostly inherited autosomal recessive.
Autosomal means that this eye disease can be inherited from a female as well as from a male to the offspring. Recessive means that a dog carries the information for the disease PRA in its genetic material, but does not suffer from it. .
Carrying out DNA test
Please have the veterinarian of your choice take a sample (EDTA blood or mucosal swab) of your Gordon Setter. Present the following forms and the dog's pedigree to the vet:
Examination order LABOKLIN PRA form of the GSCD
The material will then be examined at the LABOKLIN laboratory in Bad Kissingen, Germany. As soon as the test result is available, it will be sent to you.
Please send the original PRA form of the GSCD, signed by the veterinarian, to the board member for breeding. As soon as you receive the result of your dog from the laboratory, please send a copy of it to the member of the board for breeding of the GSCD.