PRA (Progressive Retinal Atrophy) in Dogs: Testing and Breeding Decisions

Progressive Retinal Atrophy (PRA) is a group of inherited diseases that cause progressive degeneration of the retina, leading to night blindness first and eventually complete blindness. Unlike many inherited conditions, PRA always results in blindness if a dog is affected — there is no treatment. DNA testing allows breeders to identify carriers before any vision loss occurs and breed away from the condition over time.

What Is PRA?

PRA is not a single disease but a family of related conditions caused by different genetic mutations that all result in retinal photoreceptor degeneration. Different forms of PRA affect different breeds, which is why breed-specific DNA testing matters — a test for PRA in Labradors detects a different mutation than PRA in Miniature Schnauzers.

The Most Common PRA Forms

PRA-prcd (progressive rod-cone degeneration): The most widespread form, affecting over 40 breeds including Labrador Retrievers, Golden Retrievers, Cocker Spaniels, Poodles, Portuguese Water Dogs, and many others. Rod cells degenerate first (night vision), followed by cone cells (day vision) and eventual total blindness.

PRA-rcd1 and rcd4: Found in Irish Setters and some other breeds.

crd (cone-rod dystrophy): Various forms affecting breeds including Glen of Imaal Terriers.

RPGR PRA: An X-linked form found in Siberian Huskies — this is unusual as PRA in most breeds is autosomal recessive.

DNA Testing for PRA

PRA DNA tests identify whether a dog is Clear, Carrier, or Affected for the mutation relevant to its breed. Most forms are autosomal recessive:

Clear (N/N): Two normal copies — the dog will not develop PRA from this mutation and cannot pass it to offspring

Carrier (N/PRA): One normal, one mutant — the dog will not develop PRA but can pass the mutation to offspring. 50% of puppies from carrier x clear pairings will be carriers.

Affected (PRA/PRA): Two mutant copies — the dog will develop progressive blindness

Breeding Strategy

Never breed two carriers or two affected dogs. Carrier x clear pairings are acceptable — they produce no affected offspring. Use DNA testing generationally to increase the proportion of clear dogs in your breeding program.

Verifying PRA Testing

OFA publishes DNA health testing results for many breeds. PawPrint Genetics, Embark, and Animal Genetics all test for PRA in multiple breed-specific forms. When reviewing a stud dog's health testing, confirm the PRA test is the correct form for your breed.