Personally, I think it would depend on the individual and their parents and their genetic make-up. But what about overall?
A new study, conducted by the US Davis showed that the prevalence of genetic disorders among purebred and mixed-breed dogs depends on the specific condition.
Hip dysplasia and dilated cardiomyopathy are more frequent among purebred dogs. Tendency to cruciate tears, though, is more common in mixed breeds.
The study evaluated records of ninety thousand purebred and mixed-breed dogs what had been examined at UC Davis in past fifteen years. Over twenty seven thousand had one or more of the 24 genetic disorders selected for the study.
13 out of the 24 genetic disorders had about the same prevalence in purebred dogs as in mixed-breeds.
New breeds, and mixes from similar lineage were more susceptible to certain disorders.
Source article:
Purebred dogs not always at higher risk for genetic disorders, study finds