Health testing--Cystinuria in Mastiffs

One of the greatest health issues we have in Mastiffs is Cystinuria--a genetic urinary disease where the kidney forms cysteine stones.  These stones can completely block the kidneys, the ureters, the bladder, or the urethra. In Mastiffs, only the males exhibit these symptoms and test positive with the Urinary test; only one Mastiff female has every tested positive with the urinary test.

 Here is a link to he MCOA site with an excellent explanation of Cystinuria in Mastiffs----http://mastiff.org/CYSTINURIA.htm.

Here is also a link to information explaining cystinuria in Mastiffs and the new DNA marker test that has been developed.    http://www.worldmastiffforum.com/file?id=1449736

Now that you have that information in hand (and head)   here are 2 charts I have developed to show how just one dog carrying cystinuria may affect several generations of dogs.

If the male is affected by Cystinuria--

If a female is an unknown carrier---



So, it is extremely important that Mastiffs used in a breeding program be tested for cystinuria. The Cystinuria Nitroprusside test is a simple urine collection which does not require a vet visit but can easily be collected by the owner or breeder preferably 2-4 hours after the dog has eaten. The sample is chilled or frozen and shipped overnight to the PennGen testing lab at UPenn along with a filled out  Cystinuria Urine Submission Form.

Since only males exhibit symptoms, there is strong support for x-related  inheritance--mothers carry it--sons exhibit it and  daughters carry it.  So it's quite possible for Cystinuria to be carried for several generations without being detected.  Often only one in seven dogs form stones, so dogs that don't form stones may not be detected by the nitroprusside urinary test.  Until here recently, it was the best we could do--screen our dogs yearly before breeding.

Thanks to the research at UPenn, we now have DNA test for one type of cystinuria--the type that forms stones--so both males and females can be tested to see if they carry the gene (carry 1 copy of the gene), or if they are affected (carry 2 copies of the gene).  Many of us consider this a huge breakthrough in the prevention and management of this very devastating disease.

Make sure any puppy you buy is bred from Cystinuria tested  dogs.  This disease is life threatening in males who develop stones.

I have always done the Urinary testing my boys, and insisted it be done on any outside male I used for stud.  Within the next few months, I will be completing the DNA testing on all my adult breeding dogs.  I hope each and every Mastiff breeder will do the same.

Catie Arney,  KioKee Mastiffs, Hickory, NC
kiokeemastiffs@embarqmai.com