PKD is caused by a dominant gene and is believed to have originated in Persians.

Although the current GCCF registration policies bar Persians from the pedigrees of most breeds this was not always so. A study of old pedigrees will often reveal the most surprising breeds in the background, together with unregistered cats which may have been of any origin.

Since the presence of a Persian, or of a breed which is at higher risk, in the background of any breed could possibly mean that the gene for PKD was introduced into that gene pool, there is a risk that PKD could be present in many different breeds.

In those breeds where certain colours of Persians are permitted as an outcross breed, it would be worth considering amending registration policies to insist that only Persians which have been screened clear of PKD may be used as outcrosses, thus avoiding further introductions of the gene.

High Risk Breeds   

Persians
All Persian breeds have a high risk, although it is somewhat lower in Chinchillas and Golden Persians than in other colours.

Exotics
The regular matings to Persians make this a high risk breed in the same category as Persians.

Other Breeds at risk   

Asians, including Burmillas, Bombays and Tiffanies (longhaired Asians)
The fairly recent Chinchilla ancestry of many Asians means that there is a significant risk of PKD in the breed.

Birmans
Certain colours of Persian have been permitted as outcrosses for many years and may have introduced the PKD gene.

British Shorthairs
In the past, Persians were used quite commonly in British Shorthair breeding and they are still permitted in the pedigrees of some colours, so British Shorthairs should be considered at risk. The risk extends to Manx, but is probably slightly lower here because there are likely to be fewer Persians in the background.

Cornish Rex
Matings to various breeds were allowed in the past and may have introduced the PKD gene.

Devon Rex
Matings to various breeds, including Exotics, were permitted in the past and may have introduced the PKD gene.

Ragdolls
The mixed ancestry origin of this breed means that the gene could have been introduced and there could have been further introductions from outcrosses to produce the newer colours.

Snowshoes
There is a risk of PKD due to the various breeds used in the development of Snowshoes.

Low risk breeds    

Angoras (Oriental Longhairs, Javanese, Mandarins)
Although only Siamese, Balinese and Oriental outcrosses have been permitted since 1991, prior to that there were various breeds in the background, including unregistered cats.

Maine Coons
These may not be mated to any other breeds, but there may have been mixed matings, including Persian, in their distant background.

Norwegian Forest Cats
These may not be mated to any other breeds, but their recognition through the "novice class" system in Europe means that some cats have an unknown background.

Orientals
Although only Siamese outcrosses have been permitted since 1989, there are known Persians and other breeds in the distant background, so there is a risk that the PKD gene could have been introduced.

Siamese
Siamese may be outcrossed to Orientals and there are also cats of unknown origin in the background of most Siamese, so there is a slight risk that PKD could have been introduced.

Tonkinese
The Siamese ancestry means that there is a slight risk of PKD, but the Burmese ancestry reduces the risk.

Turkish Vans
Although, traditionally, Turkish Vans have not been mated to any other breeds, some imported cats have other breeds in their background so there may be a risk of PKD.

Very low risk breeds   

Due to their GCCF registration policies and the way in which they have been bred traditionally, the risk in the following breeds should be very low.

Abyssinians
Balinese
Bengals
Burmese
Egyptian Maus
Korats
Ocicats
Russians
Singapuras
Somalis