Progressive retinal atrophy or PRA is not one but a group of diseases affecting the retina at the back of the eye. These diseases over time cause the retinal cells to increasingly become abnormal. In a majority of the cases eventual outcome is total blindness. Some form of PRA has been found in over 100 different dog breeds; this includes Miniature and Toy Poodles.

The condition, as noted, is found in nearly all breeds and is inherited as an autosomal recessive trait, the exception being the Siberian Husky, because of an inherited X chromosome linked trait, and the Bullmastiff which inherited an autosomal dominant trait. At this time there is no known treatment.

PRA is an inherited trait, meaning the disease genes which cause PRA are passed on from generation to generation. In Toy and Miniature Poodles a specific type of inherited PRA is found to predominate, however there is at least one more type which is present but appears in low frequency.

The progressive vision loss in any dog, when there is an absence of canine glaucoma or cataracts can indicate the presence of PRA.

Starting with decreased vision at night, or nyctalopia, other symptoms may appear such as dilated pupils and/or decreased pupillary light reflex.

Using fundoscopy to examine the retina will show the shrinking blood vessels, decreased pigmentation of the nontapetal fundus, increased reflection from the tapetum because of the thinning of the retina, and later as the disease progresses, a darkened and atrophied optic disc.

In order to diagnosis PRA it may require using ERG (electroretinography). For most breeds there are specific buccal mucosas or genetic tests which can be administered to check for PRA.

Not all retinal disease discovered in poodles and other dogs is PRA and not all PRA is a form currently detectable by DNA testing in our breed, therefor accurate diagnosis is essential. A dog can test as prcd-PRA (progressive rod-cone degeneration- PRA) normal or carrier and yet be affected by a different type of PRA. A yearly eye examine should be done on all breeding dogs by a veterinary ophthalmologist, even after doing the prcd-PRA testing by OptiGen.

There is a DNA test offered by OptiGen which is available to detect for the genetic mutation that causes prcd-PRA in dogs. This disorder is inherited as a “simple recessive gene,” which means that affected dogs have two copies of the abnormal gene “Â.”

The DNA test is used to discover whether a Miniature or Toy Poodle is clear, a carrier – meaning that they have one copy of the abnormal gene and one normal gene - or they are affected. Identification of breeding animals carrying or affected with prcd-PRA is imperative in order to avoid producing affected offspring.

For more on the test and its use in breeding decisions, see the OptiGen site (www.optigen.com).