Genetics plays an important part in who your pet is and being aware of what health issues are prevalent in your breed, whether a pure bred or a mixed breed, is important in knowing what you can expect in the future as they age.
OFA - Orthopedic Foundation for Animals
is the go-to website for health information for reputable breeders and anyone who wishes to learn more about breed specific disease and genetic testing. It is a searchable database, where you can look up testing on a specific dog and view their family. If you are purchasing a purebred dog from a reputable breeder - you should be able to view their lineage health here.