26/03/2026
Wcf Genetic Testing Standards
To enable the PKD test to be used in other breeds, our laboratory has set rigorous standards that consider the possibilities of phenocopies, disease heterogeneity, sporadic mutations, "de novo" mutations and breeding practices. In order to transfer a genetic test to a different breed, the following criteria have been established and we attempt to follow these standards before releasing tests for other breeds:
1. Standard clinical signs and diagnoses must first be confirmed. In the case of PKD, proof of cystic kidneys by ultrasound has been the gold standard. For PKD, the cysts need to be multiple in one kidney or present in both kidneys. Once these diagnoses were confirmed, samples were considered as "voucher" specimens for DNA testing.
2. The DNA test had to match the clinical diagnoses.
3. Once an individual was confirmed as positive by clinical and genetic diagnoses, related individuals were collected to confirm the mode of inheritance. This step is taken to help prove if a mutation is a new, sporadic event, or an inherited mutation. New sporadic events pose less risk to the population than an inherited mutation. Proving the mode of inheritance also supports that the disease is caused by the same mutation and potentially inherited from Persians.
4. A variety of cats from different lines need to be examined to support the test for the breed. For British Shorthairs, we were cautious as to whether this mutation was due to outcrossing with Persians, or a "de novo" mutation within the breed. Hence, some cats could have PKD from Persian crosses, while others have a new mutation. Some breeders perform unacceptable outcrosses, thus this step also helps to determine breed risk.
5. Families from new breeds were proven by parentage testing. Known and unknown accidents happen, thus, all research pedigrees are confirmed by parentage testing.
6. Some percentage of the breed must be examined. Hence, again, is this a localized problem, or an inherent problem within the breed. Different breeding practices for different associations and countries need to be considered. Hence, PKD in British Shorthairs from Australia may not imply that all British Shorthairs in other countries are at risk if Persians have not been a common outcross. This percentage is a slippery slope and should ideally represent the effective breeding population. This aspect of the testing may be the most difficult to establish.
7. The breed should have a clearly defined outcrossing program with cats that have a high risk for the disease, such as Persians, Exotic Shorthairs and Himalayans. Parentage testing should be used to confirm this outcrossing.
