No matter what kind of animal you are talking about, whether cats or dogs or even rabbits for that matter: as they are bred over and over again from the same bloodlines in order to try and keep a purity established, there are bound to be health defects that are introduced over time that simply cannot be eradicated.
For example the Dalmatian dog is considered a prized breed by many due to their awesome disposition and a variety of other excellent traits that make them great pets, but they have a tendency to have issues with hearing and many in fact are either born fully deaf or become that way over time.
This is direct result of the breeding patterns over many centuries that has continued that trait until the present day.
Persian cats also have some genetic traits that have been carried over from many years of breeding and in some cases inbreeding in order to keep bloodlines as pure as possible despite the fact that this can and does lead to defects and chronic health issues over time.
The most recognizable of these traits is the flattened face of the Persian which was initially bred into the line as it was considered more appealing and distinctive. Not many people know that the signature aspect of this cat has been introduced by breeders and has caused the Persian to develop a whole host of breathing and respiratory problems.
While the breed tends to have a life span of approximately 12-17 years, according to the data from British veterinarians, health issues tend to lower this in many cases, or simply results in the cats being unwell after a certain amount of years.
Persian cats are also susceptible to a condition known as Polycistic Kidney Disease.
The condition occurs in about 36-49% of all Persians and can cause kidney failure over time.
Both of these conditions can be attributed to the breeding conditions throughout history..