Persian cats are one of the breeds known to suffer from PKD (polycystic kidney disease). Below is an article about PKD. However, since the article on this page was authored, new methods of testing for PKD have been developed, specifically a DNA test which (in our opinion) is much more accurate than waiting until the cysts appear and then scanning via ultra sound. The value of DNA testing for PKD in Persian cats is that the test can be done on kittens when they are just a few weeks old. The early detection of PKD is an invaluable tool for responsible breeders of Persian cats.
In 2004, the University of California Davis developed a DNA test for feline PKD. Please note: Pelaqita Persians uses and recommends this testing facility.
IMPORTANT NOTE: Other facilities have their own tests. However, they are not based on the same protocols as those at UC Davis (as they developed the test), therefore I would be skeptical of any PKD results from any testing facility other than UC Davis. (Disclaimer: This is Pelaqita Persians' opinion only).
Polycystic Kidney Disease is an inherited kidney disease that has been found in Persian/Exotic cats. Feline Polycystic Kidney Disease (PKD) has been reported sporadically in the literature since 1967, but actual study into this renal disease did not begin until 1990. In 1990 an affected female Persian was referred to the Ohio State University teaching hospital with symptoms of renal failure. Offspring of this female were used to start a colony and begin research into this condition.
PKD is most easily diagnosed by ultrasound, which can identify the disease very early in its course. All that is required is a mid-ventral abdominal area hair-clip and a short time period for imaging to detect the possible presence of cysts. It takes a few minutes, with little or no sedation needed. It is very important that experienced personnel and proper equipment perform the ultrasound! When so, ultrasound diagnosis is 98% accurate after approximately 10 months of age. The frequency of the transducer has to be 7,5 MHz - 10 MHz, with a greyscale of 256. The higher frequency, the better details. A DNA-test for ADPKD in cats is not available at this time. Polycystic Kidney Disease is a slowly progressive disease. It clinically shows up later in life (late onset), with enlarged kidneys and kidney dysfunction on average at seven years of age. The condition is inherited and cysts are present from birth. The size of cysts can vary from less than one millimeter to several centimeters, with older animals having larger and more numerous cysts. Problems occur when these cysts start to grow and progressively enlarge the kidney, reducing the kidneys' ability to function properly. The ultimate end is kidney failure. Some of the clinical signs are depression, lack of or reduced appetite, excessive thirst, excessive urination and weight loss. There is a marked variability in how quickly individual cats succumb, with the possibility of the symptoms of PKD developing late enough in life that the cat can die of other causes before kidney failure. However, kidney failure is certain when and if the cysts grow and cause problems.
As PKD is the result of an autosomal dominant gene, it is relatively easy to track and eliminate from the breeding population. All breeding animals need to have an ultrasound to detect the possible presence of kidney-cysts. The quickest way to eliminate the problem is to neuter or spay the affected individuals and only breed from PKD-negative cats. A PKD-negative cat is also genetically PKD-free! If a particular breeding-stud or queen is extremely valuable, there is still a possibility to produce PKD-negative kittens. To achieve that, one parent has to be PKD-negative and the other parent heterozygous in its gene. Please, read more about this in the article "Autosomal Dominant Polycystic Kidney Disease in Persian Cats", by Dr David S.Biller, Dr Stephen P. DiBartola and Wilma J. Lagerwerf. The article was published in the Cat Fanciers Magazine, Feb. 1998, and can also be found on the CFA home page. Other reference articles are: Biller DS. et al; "Inheritance of Polycystic Kidney Disease in Persian Cats", Journal of Heredity, 1996 Jan. 87(1): 1-5 and Eaton KA, et al; "Autosomal Dominant Polycystic Kidney Disease in Persian and Persian-cross Cats', Vet Pathology 1997, Mar;34(2): 117-126.
It is theorized that PKD is more common in Persians/Exotics than what is currently diagnosed. With more studies and published information about this disease, breeders and veterinarians can work to establish PKD-free breeding programs. You can help in this! You can have your breeding cats ultrasounded, and aim to breed from PKD-negative individuals as soon as possible.
Copyright © Professor David S. Biller, DAVM, DAVCR,
Kansas State University, USA, and Marie Thiers, Sequoyahs Persians, Sweden
used with permission
