Dalmatian Bladder Stones: not just a Dalmatian Problem

Presentation by Danika Bannasch DVM, PhD, University of California, Davis at the 2009 National Parent Club Canine Health Conference hosted by the AKC Canine Health Foundation.

Presentation Abstract: Dogs, as well as other mammals, must excrete excess purine compounds in their urine. Most mammals excrete these excess purines in the form of allantoin; however humans, great apes and Dalmatians excrete uric acid instead. In dogs, uric acid excretion can lead to bladder stone formation. This problem in Dalmatians has been recognized for almost 100 years. We used a Dalmatian X Pointer cross to determine the location of the gene responsible and subsequently identified the mutation that causes this problem. As suspected from many years of research, all Dalmatians are homozygous (carry two copies) for the mutation. Interestingly, other breeds reported to have uric acid-containing bladder stones also have this same mutation (Bulldogs and Black Russian Terriers). In these breeds only some of the dogs are affected and genetic selection can be used to avoid producing affected dogs. This oddity of dog metabolism is not just restricted to these three breeds and in fact appears to be a very old mutation that occurs in many breeds. DNA testing is commercially available for uric acid excretion, or hyperuricosuria in dogs. However, DNA testing is not completely straightforward since the frequency of the mutation varies between breeds and not all dogs that are homozygous for the mutation will show clinical signs of bladder stones.