PRA Breeding Recommendations: A Veterinary Ophthalmologist's Guide

In twenty years of veterinary ophthalmology practice, I have examined thousands of dogs with Progressive Retinal Atrophy. Each case represents a preventable outcome. The genetic tests exist. The inheritance patterns are well understood. The mathematics of recessive disease allow complete elimination of affected offspring while retaining valuable genetic diversity. Yet PRA persists because breeding recommendations are not consistently followed.

This guide consolidates the recommendations I provide to breeders in my practice into a comprehensive framework. These are not arbitrary rules but evidence-based protocols derived from decades of population genetics research and clinical experience. Following them protects the dogs we breed, the families who adopt them, and the long-term health of our breeds.

Foundation Principle: Test Before Breeding

Every dog intended for breeding should undergo complete genetic testing before their first mating. This is non-negotiable. The cost of testing is trivial compared to the suffering of affected dogs and the damage to breeding reputations when affected puppies are produced.

Some breeds face multiple PRA variants. Golden Retrievers require testing for PRCD, GR-PRA1, and GR-PRA2. Papillons need both PRA1 and PRA2 testing. A dog clear for one variant may still be affected by another. Comprehensive panel testing, available through certified testing laboratories, provides complete information.

Mating Recommendations Based on Test Results

Once test results are in hand, breeding decisions follow straightforward rules:

*Breeding clear to affected produces 100% carriers. While no affected offspring result, this maintains the mutation in the population. Only consider in exceptional circumstances with irreplaceable genetic contributions.

The Carrier Question

Should carriers be bred? This question generates more controversy than it deserves. The mathematics are clear: a carrier bred to a clear dog produces zero affected offspring. The genetic outcome is identical to a clear-to-clear breeding from the perspective of PRA prevention.

Carriers often possess valuable traits that benefit their breeds. Eliminating all carriers immediately can devastate genetic diversity, leading to inbreeding depression and emergence of other health problems. The prudent approach retains valuable carriers while systematically reducing mutation frequency over generations.

Clinical Screening Alongside DNA Testing

DNA testing identifies known mutations but cannot detect uncharacterized PRA variants. Some breeds harbor PRA forms without identified causative genes. Annual clinical eye examinations by board-certified veterinary ophthalmologists complement genetic testing by detecting PRA that current DNA tests miss.

The OFA (Orthopedic Foundation for Animals) maintains eye examination databases. Dogs passing examination receive certification valid for one year. Because PRA can develop at any age, annual recertification throughout the breeding career provides ongoing surveillance.

For breeds with known DNA tests, clinical screening may seem redundant. However, new variants emerge from research regularly. A dog clear for all known variants might still carry an uncharacterized mutation. Clinical screening catches these cases before affected puppies are produced. Understanding the clinical signs and diagnostic process helps breeders recognize potential problems early.

Special Considerations for Multi-Variant Breeds

Some breeds face particular complexity requiring careful attention:

Golden Retrievers

With three documented PRA variants, Golden Retriever breeding requires attention to each independently. A dog might be clear for PRCD and GR-PRA1 but carrier for GR-PRA2. Such a dog should only be bred to mates tested clear for GR-PRA2, regardless of the mate's status for other variants.

Papillons and Phalenes

Two variants, PRA1 (CNGB1) and PRA2 (RPGRIP1), affect these breeds. Comprehensive testing for both variants is essential. A dog clear for one variant but carrier for another requires appropriate mate selection.

Border Collies

Border Collies face incompletely characterized PRA genetics. Available tests do not cover all variants in the breed. Heavy reliance on clinical screening alongside available DNA tests provides the most comprehensive protection until research identifies additional causative mutations.

Documentation and Transparency

Effective disease management requires information sharing across the breed community. Breeders who test but keep results private contribute less than they might to breed health improvement.

I recommend publishing all test results, including carrier and affected status, in open health databases. This transparency enables:

• Informed mate selection across the breed community
• Identification of emerging carrier clusters
• Accurate population frequency estimates
• Recognition of breeders demonstrating health commitment

Some breeders fear stigma from publishing carrier results. This fear, while understandable, perpetuates problems. A breeder who openly acknowledges carrier status and demonstrates appropriate mate selection earns respect for transparency. One who hides results and produces affected puppies damages both their reputation and their dogs.

Communication with Puppy Buyers

Puppy buyers deserve complete health information. Before placement, provide:

• PRA test results for both parents
• Expected status of puppies based on parental results
• Test results for individual puppies if tested
• Explanation of what carrier status means for non-breeding pets
• Guidance on testing if buyer intends to breed

Carrier puppies from clear-to-carrier breedings make excellent pets. They will never develop PRA. The carrier status only matters if the puppy is later bred, and even then, appropriate mate selection produces zero affected offspring. Educated buyers appreciate this transparency and respect breeders who provide it.

Long-Term Breed Management

Individual breeding decisions aggregate into population-level outcomes. Each generation of thoughtful breeding reduces mutation frequency while maintaining the genetic diversity breeds need for long-term health.

The goal is not immediate elimination of all carriers but gradual reduction to frequencies where carrier-to-carrier breedings become statistically improbable even without universal testing. Achieving this goal requires patience, discipline, and collective commitment from breed communities.

Breeds that have most successfully managed PRA share common characteristics: strong breed club leadership on health issues, accessible health databases, educational resources for new breeders, and cultural norms that make testing standard practice rather than optional enhancement.

When Gene Therapy Is Not a Breeding Substitute

Advances in gene therapy offer hope for affected individuals but do not change breeding recommendations. A dog successfully treated with gene therapy retains their genetic status. They would still pass mutations to offspring. Treatment addresses individual suffering without addressing population-level disease burden.

Prevention through appropriate breeding remains more practical, economical, and widely accessible than treatment. Gene therapy may eventually provide options for the occasional affected dog that slips through despite careful testing, but it cannot replace the systematic approach that prevents affected dogs from being born.

Summary of Recommendations

1. Test all breeding stock for all known PRA variants in the breed before first mating.
2. Never breed carrier to carrier, which would produce 25% affected offspring.
3. Use carriers strategically when they offer valuable genetic contributions, always paired with clear mates.
4. Maintain clinical screening to catch PRA variants without available DNA tests.
5. Document results openly in breed health databases.
6. Educate puppy buyers about testing, results, and their implications.
7. Support research to identify new variants and develop treatments.

These recommendations, consistently applied, make PRA a preventable condition. The tools exist. The knowledge is established. What remains is the collective decision by breed communities to use them. Every affected puppy born today represents a failure to apply available knowledge. Our responsibility to the dogs we breed demands better. The Herding Gene resource provides additional breeding guidance for inherited conditions across multiple breeds.

Dr. Amanda Foster, Veterinary Ophthalmologist