Junior to adult onset
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.
At risk dogs are highly likely to show signs of this disease in their lifetime.
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.
XLPRA1 is due to the degeneration of rod photoreceptors. Clinical signs such as night blindness and “tunnel vision” are observed typically at the age of 2 to 4 years. The disease is progressive and after onset will result in blindness within a few years.
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).
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.
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