Hyperuricosuria (HUU) describes elevated levels of uric acid in the urine, resulting in urolithiasis, the formation of calculi (stones) in the urinary tract. These stones form in their bladders or sometimes kidneys, requiring surgical removal. These stones can be difficult to treat. HUU can occur in any breed but is most commonly associated with the Dalmatian, as Dalmatians are homozygous for HUU (HU/HU). Outcrossing programs have introduced ?low uric acid? dogs, derived from Dalmatian x Pointer backcrosses, into the purebred gene pool, providing a means for breeders to reduce incidence of the disease and maintain the breed characteristics. This mutation is not the sole cause of urate bladder stones in dogs, so may not account for other causes of stones, such as liver disease and diet.