Posted Date: July 22, 2015
Genetic testing can help you identify an emergency medical situation quickly. By Dr. Lisa Shaffer
Many of you know Rickie Roo, USDAA's Roving Reporter, from her interviews and articles on USDAA.com or know her as a feisty competitor who travels to the various regional and national events. Perhaps you missed her presence at the 2013 Cynosport World Games or had heard that she was dealing with a medical issue. She was, and it was a very serious issue, primary lens luxation (PLL). This condition could have taken not only her sight, but quite possibly could have required removal of her entire eye.
PLL is a genetic condition that affects the ligaments that holds the lens of the eye in place. When those ligaments fail, the lens dislocates and it becomes an emergency situation. This disease affects many breeds of dogs. DNA testing is now available for the mutation found in the ADAMTS17 gene.
However, that wasn't always the case. Rickie Roo was bred and born before the mutation was identified and the test was developed. After the test became available, Roos breeder, Barbie Trammel, tested her breeding stock and contacted anyone who might either have purchased an affected dog or one that might carry the mutated gene.
Roo's DNA was then tested for the mutation known to cause PLL and found to be at-risk. With this information, Roo's owner and trainer, Deborah Davidson-Harpur, knew that the condition was a possibility and became familiar with the signs of lens dislocation. However, being at-risk for PLL does not guarantee your dog will develop a lens luxation. Roo had an unrelated eye injury before the DART 4 star event a few years back and at that time Roo and her owner met with Christin Fahrer, DVM, MS, DACVO of Eye Care for Animals and built an important relationship with her to oversee Roo's on-going eye evaluations.
When the day came that Roo started showing signs of a dislocating lens, Roo's owner, Deb, acted quickly to get Rickie Roo to her veterinary ophthalmologist. Roo underwent surgery to remove the lens, which saved her eye and her vision. Unfortunately, with this disease, both lenses can dislocate and sadly, the second lens dislocated within weeks of Roo having surgery to remove the first lens.
"At the time [I got Roo tested] PLL was talked about in whispers like it was the end of everything if your dog got it," said Deborah Davidson-Harpur. "I was shocked when I met with our eye specialist and found out that it could be treated if dealt with promptly."
Rickie Roo may be a little dog with a disability, but she has a big heart and lives to do agility. She has her veterinarian's permission to compete and although she is now far-sighted and has no depth perception, she has her vision, and what her owner Deb calls, "a great RAT-ITUDE," and thanks to the knowledge her owner got from genetic testing, Roo continues to compete with the top dogs in agility.
PLL is just one example of a genetic condition that can affect your dog. Genetic testing allows you to be prepared for future medical issues and have the ability to identify a problem in an emergency situation. Because of the genetic testing, Deb Harpur was informed and prepared. This preparedness was essential to getting Roo the excellent care that she received and saving her eyesight.
Like many genetic conditions in dogs, PLL is inherited in a recessive manner, meaning that most dogs must have two copies of the mutation in order to have the disease. While true that in most cases that carriers of the mutation do not show symptoms of the disease, in rare instances, some carrier dogs have been reported to have lens dislocations. Therefore, all dogs that test as affected or at-risk (two copies of the mutation) or carriers (one copy of the mutation and one copy of the normal gene) should be periodically checked by a veterinary ophthalmologist for signs of luxation.
In addition, you should watch for sudden changes in behavior and any squinting, excessive blinking or pawing at the eye, which may indicate a sudden lens problem that will need immediate attention. Surgery can be costly, estimated around $4,300 per eye to remove the damaged lens.
To know if your dog may be at-risk for genetic disease, you can have your dogs DNA examined for mutations found in your breed. Paw Print Genetics offers genetic testing for most breeds and also offers the Canine HealthCheck for genetic screening of mixed breed dogs and welcomes the opportunity to discuss your dog's genetic health with you. We know that having healthy, happy dogs is your primary objective and we are here to help.
Photos by Deborah Davidson Harpur and Mike Lifer Photography.
Lisa G Shaffer, PhD, FACMG is a board certified geneticist by the American Board of Medical Genetics and CEO of Paw Print Genetics. She has published over 300 peer-reviewed medical articles and 4 books on the subject of clinical genetics. After firmly establishing her career in human medical genetics, Dr. Shaffer founded Paw Print Genetics to provide access for every dog owner to genetic testing for optimal canine health.