Progressive Retinal Atrophy (PRA-PRCD) in the Biewer Terrier*

Educational Information for Biewer Terrier Owners

Introduction

Understanding an Inherited Eye Disease and the Importance of DNA Testing

Healthy vision is essential to a dog’s quality of life. Progressive Retinal Atrophy (PRA-PRCD) is an inherited eye disease that causes gradual degeneration of the retina, eventually leading to blindness. Although there is currently no cure, DNA testing and routine eye examinations allow breeders and owners to make informed decisions that help reduce the occurrence of this disease in future generations. The Biewer Terrier Club of America (BTCA) includes PRA-PRCD testing among its recommended health screenings for breeding dogs.

What is Progressive Retinal Atrophy (PRA)?

Progressive Retinal Atrophy (PRA) is a group of inherited retinal diseases that gradually destroy the light-sensitive cells (photoreceptors) of the retina.

The form recognized in the Biewer Terrier is Progressive Rod-Cone Degeneration (PRA-PRCD).

  • Rod cells are affected first, causing loss of night vision.
  • Cone cells are affected later, resulting in loss of daytime vision.
  • The disease progresses slowly and eventually leads to blindness.
  • PRA is not painful, and affected dogs usually adapt remarkably well to gradual vision loss.

Cause and Inheritance

PRA-PRCD is caused by a mutation in the prcd gene and is inherited as an autosomal recessive trait.

Clinical Signs

Because PRA develops gradually, owners often notice subtle changes first.

Common signs include:

  • Difficulty seeing in dim light or at night
  • Hesitation going down stairs or entering dark rooms
  • Bumping into furniture or unfamiliar objects
  • Dilated pupils
  • Increased eye shine (reflectivity)
  • Progressive loss of daytime vision
  • Eventual blindness

Most affected dogs remain comfortable because PRA is not painful. Cataracts may develop later in the disease.

Diagnosis

Testing may include:

  • Complete ophthalmic examination by a board-certified veterinary ophthalmologist (ACVO Diplomate)
  • Electroretinography (ERG), which can detect retinal dysfunction before visible retinal changes occur
  • DNA testing for the prcd mutation
  • Routine ACVO eye examinations as recommended by the breed health guidelines

Treatment

There is currently no treatment or cure that stops or reverses PRA.

Management focuses on:

  • Maintaining a consistent home environment
  • Avoiding rearrangement of furniture
  • Keeping dogs on a leash in unfamiliar areas
  • Protecting dogs from hazards
  • Monitoring for secondary cataracts or other eye conditions

Most dogs adapt extremely well and continue to enjoy an excellent quality of life despite vision loss.

Breeding Considerations

The BTCA recommends:

  • DNA testing for PRA-PRCD pre-breeding
  • Routine ACVO eye examinations before breeding and at recommended intervals
  • Using DNA results to make informed breeding decisions while maintaining genetic diversity

Responsible breeding can greatly reduce the risk of producing affected puppies without unnecessarily removing healthy carriers from breeding programs.

Important Points

  • PRA-PRCD is inherited.
  • It is not contagious.
  • It is not painful.
  • DNA testing identifies Clear, Carrier, and Affected dogs.
  • Early diagnosis helps owners prepare for progressive vision loss.
  • Responsible breeding using DNA testing, assessing for the presence of the mutation, is the most effective way to reduce PRA within the breed.

Disclaimer

*This educational handout compiles information from publicly available veterinary literature and does not represent original research, official policy, or guidance of the Biewer Terrier Club of America (BTCA). It is intended for educational purposes only and is not a substitute for professional veterinary diagnosis or treatment. Owners should consult their veterinarian or a board-certified veterinary ophthalmologist regarding any concerns about their dog’s vision or eye health.

Educational Resources & Further Information