Cord1 PRA test is not recommended for the diagnostic of cord1 PRA becaue a recent study found that the mutation is not solely responsible for early-onset cone-rod dystrophy, and that there is another unidentified mutation involved in the development of cord1 PRA

we continue to offer the test to breeders who are interested in controlling this mutation within the breed but only on the understanding that this mutation is not the primary cause of Cord1 PRA. The test is also available for research purpose.

The retina is a thin layer of neural cells that lines the back of the eyeball. The vertebrate retina contains photoreceptor cells (rods and cones) that respond to light. The cones mediate high-resolution vision and colour vision. The rods mediate lower-resolution, black-and-white, night vision.

The degeneration of the retina results in loss of vision, often leading to blindness. There is currently no treatment for the disease. In contrast to rod-cone dystrophies, where firstly, rod cells are affected and secondly, degeneration of the cone cells results in complete blindness of the dog, cone-rod dystrophies are characterised by the relatively early loss of cone photoreceptors.

The earliest ophtalmoscopic signs could appear about six month of age but some dogs with the mutation are not diagnosed until much later in life, so owner may never see behavioural changes and never recognise that the dog can pass the mutation onto its offspring.

Since diagnosis of retinal diseases in dogs may prove difficult, the genetic test on cord1-PRA helps to diagnose a specific form of a disease and is also a useful tool for breeders to eliminate the mutated gene from the dog population.

By DNA testing, the responsible mutation can be shown directly. This method provides a test with a very high accuracy and can be done at any age. It offers the possibility to distinguish not only between affected and clear dogs, but also to identify clinically healthy carriers. This is an essential information for controlling the disease in the breed, as carriers are able to spread the disease in the population, but can not be identified by means of common laboratory diagnostic.