Polycystic Kidney Disease is a genetic mutation causing benign cysts in the kidneys and other organs. The disease progresses at very different rates, but can cause early death. It is quite common in the Persian breed. Several breeders in Russia and the U.S. have used Persians some Siberian matings in an effort to increase coat density and round the face. These outcrosses have brought several genetic Persian diseases into the breed, - including Persian Polycystic Kidney Disease (PKD1).

In October of 2006, SRI submitted a pedigree analysis of Siberians affected by PKD to Dr Leslie Lyons of UC Davis. PKD has long been considered to be a Persian disease, but has also been found in other breeds as well. Roughly 35 cases of PKD have been reported directly to SRI with the majority of participating catteries requesting confidentiality. Extrapolation by a population geneticist estimated that PKD currently affects between 500 and 1000 Siberians worldwide.

Dr. Leslie Lyons has offered free DNA testing of Siberians that have been shown to have PKD by ultrasound. These cats will be tested for the known Persian PKD mutation. SRI submitted requests to catteries to provide DNA where ultrasounds showed that a Siberian had the disease. Not all cats with PKD are positive for the Persian mutation. At this time, Dr. Lyons does not have sufficient samples to formally comment on Siberian PKD, but DNA analysis of most samples submitted by SRI were positive for the Persian PKD test.

Traditional PKD is a dominant gene, and since the disease always shows in affected offspring it is fairly simple to track the lineages involved. Pedigree analysis have revealed five potential distinct entry points of PKD in the Siberian breed, though new cases in kittens imported from Russia are still being reported.

  1. 1.The majority of reported PKD cases come from the mating of Kuzya and Lemurotchka. Germany currently has the highest concentrations of this line, but it has also been widely dispersed in the U.S. and several other countries. These cases consistently test positive using the Persian PKD DNA test. Roughly half of the offspring from Kuzya have been shown to have PKD.

  1. 2.Pyramid Kazan of Croshka and his daughter died very young of PKD, with confirmation by necropsy. Samskatts Texas Star also tested positive, and is from the same ancestry. The focal point for these pedigrees is: Gesha Olenya Krasa - Dolka Olenya Krasa - and Dima El Magrib. This line can be tested using the standard PKD gene test.  Revised July 2010.

  1. 3.Gregory's Siberian Petra Jamesova and Gregory's Siberian Penelope Jamesova. Associazione del Gatto Siberiano has reported two siblings with PKD. Both cats have had extensive workups, and the diagnosis was confirmed by DNA. Of specific concern however, DNA was also sent to UC Davis where it tested negative. Dr. Lyons confirmed that there are small variations between the tests that could account for this result, but has begun full sequence of the sample in an effort to isolate any potential differences. This line should be tested by ultrasound until this study is concluded.

  1. 4.Uliana Golden Assolada (same pedigree as linked here) was diagnosed with PKD by ultrasound, but was not tested by DNA. No additional cases have been reported from this line.

  1. 5.Two imported siblings in the UK were diagnosed by genetic testing and returned to the breeder in Russia. No additional cases have been reported on that line, but the majority of cases go unreported. Both kittens tested positive for Persian PKD, indicating an outcross with Persian.

By breeding age, PKD can usually be seen by ultrasound (some cysts are too small to show clearly on ultrasound). The affected parents will always show positive DNA results. While genetic testing of Siberians for the Persian PKD mutation has not been scientifically validated by Dr. Leslie Lyons, SRI has documented that the Persian gene test is always effective on the Kuzya X Lemurotchka line. We suggest kitten buyers and catteries are cautious when purchasing kittens descended from any of the matings listed above.

    1. 1.Request six generation pedigrees before purchasing pets or breeding cats. Current pedigree depth on the Kuzya / Lemurotschka lines is now greater than seven generations. In a recent case, the Russian pedigree had been "shortened" by two generations to remove the Kuzya/Lemurotschka mating. We have seen this type of pedigree fraud several times.

    1. 1.Gene tests on all cats/kittens descended from the Kuzya / Lemurotschka mating.

    1. 1.Request ultrasound results on all cats from the Gregory's line shown above, and ultrasound all descendants before breeding.

Resources for research and testing of PKD are listed below.  Breeders are strongly encouraged to review the specific lines known to be impacted with PKD prior to purchase or breeding kittens.

Genetic Screening for Feline Persian Polycystic Kidney Disease (PKD)
The UC Davis website states the current before it s used to screen non-Persian related cats. The majority of Siberian PKD can be tested with the UC Davis test, but one set of PKD samples tested negative. Because non-Persian PKD is known, it is prudent to test cats descended from the Gregory's lines by ultrasound.

The Feline PKD Home Page
Includes definitions and frequently asked questions about PKD

Autosomal Dominant Polycystic Kidney Disease in Persian Cats
Definitions, diagnosis, treatment, and offspring probabilities (by Biller et al).

Feline Polycystic Kidney Disease Mutation Identified in PKD1
Journal of the American Society of Nephrology (by Lyons et al).

Gesunde-Rassekatzen (German Siberian Health Database)
Nice German Database with HCM, PKD, and blood group records.

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