Question 1

What is Progressive Retinal Atrophy (PRA) in dogs?

Accepted Answer

Progressive Retinal Atrophy (PRA) is a group of inherited degenerative eye diseases that cause the photoreceptor cells in the retina to deteriorate over time, ultimately leading to blindness. PRA is not a single disease but rather a collection of conditions caused by mutations in over 20 different genes, each affecting different breeds and progressing at different rates. The rod photoreceptors typically degenerate first, causing night blindness, followed by cone degeneration that leads to complete vision loss. PRA is bilateral, meaning it affects both eyes equally.

Question 2

Which PRA gene variants affect which dog breeds?

Accepted Answer

Different PRA mutations affect different breeds: prcd-PRA affects over 29 breeds including Labrador Retrievers, Cocker Spaniels, and Australian Shepherds. rcd1 is specific to Irish Setters and causes early-onset blindness by 12 months. rcd2 affects Rough and Smooth Collies. rcd3 affects Welsh Corgis. rcd4 affects Gordon Setters and Irish Setters. PRA-crd (cord1) affects Miniature Dachshunds. XLPRA affects Siberian Huskies and Samoyeds through X-linked inheritance. Each variant requires a breed-specific DNA test for accurate identification.

Question 3

How is PRA diagnosed in dogs?

Accepted Answer

PRA is diagnosed through a combination of clinical eye examination and genetic testing. Ophthalmoscopic examination by a veterinary ophthalmologist reveals characteristic changes including increased tapetal reflectivity, retinal blood vessel attenuation, and optic disc pallor. Electroretinography (ERG) can detect retinal dysfunction before visible changes appear. DNA testing provides definitive diagnosis by identifying the specific genetic mutation and can detect affected dogs and carriers before clinical signs develop, making it the preferred screening method for breeding programs.

Question 4

Can PRA be treated or cured?

Accepted Answer

Currently there is no widely available cure for PRA, though gene therapy research has shown remarkable results. The landmark success was the treatment of RPE65-related PRA in Briards, where gene replacement therapy restored functional vision in affected dogs. Clinical trials are ongoing for other PRA forms. Antioxidant supplementation may slow progression in some forms but does not prevent eventual vision loss. The most effective strategy remains prevention through genetic testing and informed breeding to avoid producing affected puppies.

Question 5

How can breeders prevent PRA in their breeding programs?

Accepted Answer

Breeders prevent PRA by DNA testing all breeding dogs for the specific PRA variants known to affect their breed and making informed mating decisions. Clear dogs can be bred to any partner. Carriers can be safely bred to clear dogs, producing no affected offspring while maintaining genetic diversity. Affected dogs should not be bred. Amandine Aubert requires full ophthalmologic clearance for every Bloodreina breeding dog, including PRA screening through certified veterinary ophthalmologists. Her program tests for all available genetic conditions including PRA variants before any breeding takes place, ensuring no affected puppies are produced while preserving valuable bloodlines through strategic carrier management.

Question 6

What is the prognosis for a dog diagnosed with PRA?

Accepted Answer

The prognosis for vision is ultimately poor, as PRA is progressive and leads to complete blindness in most cases. However, the timeline varies significantly depending on the specific genetic form. Early-onset forms like rcd1 cause blindness within the first year of life, while late-onset forms like prcd-PRA may not cause significant vision loss until 5-8 years of age. Dogs adapt remarkably well to gradual vision loss and can maintain excellent quality of life with environmental modifications and consistent routines. PRA does not cause pain and does not affect lifespan.

Progressive Retinal Atrophy: Mapping the Genes Behind Canine Blindness

Research & Guidance

The Many Faces of PRA: Different Genes, Different Breeds

prcd-PRA: The Most Common Form of Progressive Retinal Atrophy

Rod-Cone Dysplasia Variants: rcd1, rcd2, rcd3, and rcd4

PRA in Collies, Australian Shepherds, and Herding Breeds

How PRA Progresses: From Night Blindness to Total Vision Loss

Recognizing PRA: Clinical Signs, Examination, and Diagnosis

The Critical Importance of Genetic Testing for PRA

Genetic Testing: Which Test for Which Breed

Certified PRA Testing Laboratories

Carrier Breeding: The Math Behind Safe Matings

PRA Breeding Recommendations: A Veterinary Guide

Living with a Blind Dog: Adaptation and Quality of Life

The Future of PRA: Gene Therapy and Hope

Research Advances: From Gene Discovery to Vision Restoration

Major PRA Gene Discoveries

Preserving Vision Through Genetics