Study shows genetic disorders in dogs not necessarily linked to breed

A recent study out of the University of California Davis is casting some doubt on a long-held belief that purebred dogs are more inclined to acquire genetic disorders than mixed-breed dogs. The study results, published online in the June issue of the Journal of the American Veterinary Medical Association, could prove to be instrumental in preventing and treating certain conditions in both people and dogs.

During the course of the study, researchers evaluated the medical records of more than 90,000 purebred and mixed-breed dogs that were examined at the university’s veterinary medical teaching hospital between 1995 and 2010. Of those dogs, 27,254 were found to have at least one of 24 genetic conditions, which included various neoplastic, cardiac, endocrine and orthopedic diseases. These disorders were isolated for the study because they can be accurately and readily diagnosed, are highly prevalent in canine populations and are serious enough to warrant medical attention. Additionally, they represent a wide variety of physiologic systems in the body.

The results showed that the incidence of 13 of the 24 genetic disorders was approximately the same in both purebred and mixed-breed dogs. Ten of the conditions were found more often in purebred dogs and one was more common in the mixed-breed population. For example, elbow dysplasia and dilated cardiomyopathy were more commonly seen in purebreds, while cranial cruciate ligament rupture was more prevalent among the mixed-breed dogs.

Additionally, the data revealed that certain genetic disorders, such as elbow dysplasia, were found more often in recently derived breeds or breeds of a similar lineage. Comparatively, disorders that were equally prevalent among both purebred and mixed-breed dogs, such as hip dysplasia and most cancers, appeared to represent older gene mutations that are commonly found among varied dog populations.

“Overall, the study showed that the prevalence of these genetic disorders among purebred and mixed-breed dogs depends on the specific condition,” says animal physiologist Anita Oberbauer, Ph.D., professor and chair of the Department of Animal Science at UC Davis and lead author of the study, in a release issued by the university. “Results from this study give us insight into how dog breeding practices might be modified to reduce the prevalence of certain genetic disorders.”