Dogs affected by Xanthinuria (Type II) lack proper enzyme activity required for this conversion, causing xanthine to accumulate within the body and urinary system.
Because xanthine does not dissolve easily in urine, affected dogs are at increased risk of developing xanthine crystals and urinary stones, also known as uroliths. These stones may form in the kidneys, bladder, ureters, or urethra, leading to irritation, inflammation, and urinary tract complications. The severity of the condition can vary widely. Some dogs may show signs early in life, while others may remain symptom-free for long periods despite carrying the genetic mutation.
Clinical signs associated with Xanthinuria (Type II) often relate to urinary tract problems. Common symptoms include difficulty urinating, straining to pass urine, increased frequency of urination, blood in the urine, urinary accidents, abdominal discomfort, and recurrent urinary tract infections. In severe cases, urinary stones can cause partial or complete urinary blockage, which is considered a veterinary emergency and may become life-threatening if not treated quickly. Kidney damage may also occur in chronic or untreated cases.
Xanthinuria (Type II) is inherited in an autosomal recessive pattern. This means a dog must inherit two copies of the defective gene — one from each parent — to be affected by the disease. Dogs with only one copy are known as carriers. Carrier dogs usually do not develop symptoms themselves, but they can pass the mutation to their puppies. When two carrier dogs are bred together, there is a 25% chance of producing affected puppies, a 50% chance of producing carrier puppies, and a 25% chance of producing genetically clear puppies.
The Xanthinuria (Type II) genetic test is designed to identify whether a dog is clear, a carrier, or affected by the mutation associated with the disease. Testing is simple, non-invasive, and typically performed using either a cheek swab or blood sample. The collected DNA sample is analyzed in a laboratory to detect the presence or absence of the mutation responsible for the disorder.
Genetic screening plays an important role in responsible breeding programs. By testing breeding dogs before mating, breeders can avoid carrier-to-carrier pairings and significantly reduce the risk of producing affected puppies. The test also helps preserve breed health by limiting the spread of the mutation within future generations. For owners, knowing a dog’s genetic status allows for early monitoring and preventive care, even before symptoms appear.
Although there is currently no permanent cure for Xanthinuria (Type II), affected dogs can often live comfortable lives with proper management. Treatment may include a low-purine diet, increased water intake, routine urinary monitoring, and veterinary care to prevent or manage stone formation. In some cases, surgical removal of urinary stones may be required.
Testing for Xanthinuria (Type II) supports informed breeding decisions and promotes the long-term health, welfare, and quality of life of dogs.
