PRA3 in Tibetan Spaniels: Genetic Eye Disease Guide

Progressive Retinal Atrophy (PRA) is a group of inherited degenerative eye diseases that lead to irreversible blindness in affected dogs, including the Tibetan spaniel. PRA3 is one specific form prevalent in this breed, causing a slow onset, progressive loss of vision without pain.

Understanding PRA3 in Tibetan spaniels is crucial for owners and breeders alike to manage this condition responsibly and protect the breed's health.

What is Progressive Retinal Atrophy 3 (PRA3)?

PRA3 is a genetic disorder caused by a mutation in the FAM161A gene. This gene is essential for the function of photoreceptor cells in the retina — the rods and cones that detect light and colour. Find Tibetan spaniel puppies from reputable breeders who test for this condition.

Dogs with PRA3 experience progressive degeneration of these photoreceptors, beginning with rod cells, which affects night vision first. The disease usually presents clinically around 6 to 7 years of age, though subtle signs can occasionally be detected earlier by veterinary eye specialists. Ultimately, affected dogs lose spatial and colour vision, culminating in total blindness.

How does PRA3 affect Tibetan spaniels?

The main symptoms appear gradually, often starting with difficulties seeing in low light or at night, frequently noticed by owners as increased cautiousness in dim environments or bumping into objects. As the disease progresses, dogs will experience a further decline in vision during the day until blindness is complete.

Secondary issues such as cataracts may develop late in the disease, but removing cataracts does not restore sight due to retinal cell loss. PRA3 is non-painful but substantially diminishes quality of life without proper management and environment adaptations.

Inheritance and genetics of PRA3 in Tibetan spaniels

PRA3 follows an autosomal recessive inheritance pattern. This means that a dog must inherit two copies of the mutated gene — one from each parent — to develop the disease. Find puppies with clear genetic backgrounds through authorised breeders who utilise genetic testing.

Different combinations of parental gene status influence offspring results:

• If both parents are clear of the mutation, puppies will be clear and unaffected.
• If both parents are carriers, puppies have a 25% chance of being affected, 50% as carriers, and 25% clear.
• If one parent is affected and the other clear, all offspring will be carriers.
• If one parent is affected and the other a carrier, puppies have a 50% chance of being affected and a 50% chance of being carriers.

How common is PRA3 in the breed?

Approximately two-thirds of all PRA cases in Tibetan spaniels are caused by the PRA3 mutation. Around 25% of Tibetan spaniels in the UK are carriers, while about 3% are affected by the condition.

How to test your Tibetan spaniel for PRA3

Testing for PRA3 is performed through a DNA cheek swab sample sent to approved veterinary genetics laboratories. Your vet can collect this sample and facilitate testing. The results classify dogs as clear, carrier, or affected, guiding responsible breeding decisions.

Because PRA3 is relatively common in the breed, breeding decisions must balance reducing disease incidence with maintaining genetic diversity to avoid other hereditary issues.

Living responsibly with a dog affected by PRA3

No treatment can reverse or cure PRA3 currently. Supportive care focuses on helping affected dogs adapt to vision loss, such as using consistent household layouts, teaching cue-based navigation, and ensuring safety indoors and outdoors.

Early diagnosis through veterinary ophthalmology can assist the owner in planning adaptations to maintain the dog’s quality of life.

Summary

Progressive Retinal Atrophy 3 (PRA3) is an autosomal recessive, late-onset hereditary retinal disease in Tibetan spaniels caused by a FAM161A gene mutation. It leads to progressive vision loss and eventual blindness. Responsible breeding using genetic testing reduces incidence, while supportive care helps affected dogs live comfortably.

For those considering Tibetan spaniel puppies, always seek reputable breeders who perform PRA3 testing to ensure healthy puppies and contribute to the dog’s welfare.