While hip Displasia and PRA are two of the worst and most common genetic disorders,
each dog breed has its own unique set of genetic problems and diseases. There are two large foundations that grade and register dogs that have been tested. The Canine Eye Registration Foundation (CERF) "www.vet.purdue.edu/~yshen/index.html" sets the standards for eyes, while the Orthopedic Foundation for Animals (OFA) "www.offa.org" sets the standards for hips, elbows, heart, thyroid and patellar luxation. 

With all the wonderful genetic testing available today, one might ask why these genetic problems are so common. The main reason is that many breeders are not responsible enough to do them, and most puppy buyers are not knowledgeable enough to require them. Buying a puppy from a responsible breeder who does the proper genetic testing drastically reduces the risks, but does not eliminate them. Two properly certified parents can still produce a genetically unsound puppy in cases where both parents carry an undetectable recessive gene for the disease.

Although genetic testing is not perfect, you can greatly improve your chances of getting a genetically sound puppy by insisting that both parents have met the standards of genetic soundness that apply to their particular breed. The secret to avoiding genetic diseases is to buy a puppy from a respectable breeder who is intimately familiar with the genetic background of several generations of your puppy's pedigree.