X-Linked Progressive Retinal Atrophy 2

X-Linked Progressive Retinal Atrophy 2 (XLPRA2) causes early-onset degeneration of the light detecting retina at the back of the eye, resulting in loss of vision.

Key Signs

Night blindness, Blindness

Age of Onset

0 to 2 yrs

Juvenile onset


X-linked Recessive

For X-linked recessive disorders, the genetic variant is found on the X chromosome. Female dogs must have two copies of the variant to be at risk of developing the condition, whereas male dogs only need one copy to be at risk. Males and females with any copies of the variant may pass the disorder-associated variant to their puppies if bred.

Likelihood of the Condition

High likelihood

At risk dogs are highly likely to show signs of this disease in their lifetime.

What to Do

Here’s how to care for a dog with XLPRA2

Partner with your veterinarian to make a plan regarding your dog’s well-being, including any insights provided through genetic testing. If your pet is at risk or is showing signs of this disorder, then the first step is to speak with your veterinarian.

For Veterinarians

Here’s what a vet needs to know about XLPRA2

Clinical signs such as night blindness and “tunnel vision” are observed typically 6 to 7 weeks of age. The disease is progressive and after onset will result in blindness by 2 years of age.

A blind dog tends to adapt well to the loss of vision. However, some dogs may exhibit a tentativeness when introduced to unknown environments because their vision is compromised. Occasionally, they may react abruptly (snapping) if they are startled so caution and use of verbal queues should be taken when handling a blind dog. Caretakers should take precautions to protect the blind dog from threats it cannot detect (such as cliffs, sharp points on furniture, moving vehicles).

For Breeders

Planning to breed a dog with this genetic variant?

There are many responsibilities to consider when breeding dogs. Regardless of test results it is important that your dog is in good general health and that you are in a position to care for the puppies if new responsible owners are not found. For first time or novice breeders, advice can be found at most kennel club websites.

This disorder is X-linked recessive, meaning the genetic variant is found on the X chromosome. Given males only have one X chromosome, a single affected copy will increase the risk of being diagnosed with the disorder. Females typically require two copies to be at an elevated risk. Use of dogs with one or two copies of the variant is not recommended for breeding as there is a risk that the resulting litter will contain affected puppies. Please note: It is possible that clinical signs similar to the ones caused by this variant could develop due to a different genetic or clinical cause.

Technical Details

Variant Deletion
Chromosome X

References & Credit

Credit to our scientific colleagues:

Zhang, Q. (2002). Different RPGR exon ORF15 mutations in Canids provide insights into photoreceptor cell degeneration. Human Molecular Genetics. View the article

Zangerl, B., Johnson, J. L., Acland, G. M., & Aguirre, G. D. (2007). Independent origin and restricted distribution of RPGR deletions causing XLPRA. Journal of Heredity, 98(5), 526–530. View the article