Disease overview

Xanthinuria is an inherited disorder that is characterized by dysfunction of purine breakdown, which leads to accumulation of xanthine in the urine. With this increased accumulation, xanthine can precipitate out of the urine, forming stones and leading to possible secondary kidney damage. Xaninthinuria, Type I, is caused by a dysfunction in enzyme Xanthine dehydrogenase, whereas Type II is caused by a dysfunction in Molybdenum cofactor sulfurase. Both lead to the same clinical outcomes.

Gene name

MOCOS

Inheritance

Autosomal recessive

Signs and symptoms

Without stone formation, affected dogs will show no signs. As the stone develops and causes irritation, clinical signs can include straining to urinate, frequent urination, urgency, and blood in the urine. Stone formation appears to be more common in males. If an obstruction forms, urination will cease with frequent straining. This is an emergency situation. Microcrystals may enter the kidneys and lead to kidney damage. Stone formation can occur at any age.

How is it diagnosed

A veterinarian will conduct a thorough exam, including a review of health history and any clinical signs. Laboratory testing will be conducted and an ultrasound may be used to visualize the stones. Genetic testing is necessary to determine if there is an underlying genetic cause, which can assist veterinarians with diagnosis and help breeders identify affected and carrier dogs.

Breeds at higher risk

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Citations

Tate NM, Minor KM, Lulich JP, Mickelson JR, Berent A, Foster JD, Petersen KH, Furrow E. Multiple variants in XDH and MOCOS underlie xanthine urolithiasis in dogs. Mol Genet Metab Rep. 2021 Sep 17;29:100792. doi: 10.1016/j.ymgmr.2021.100792. PMID: 34584846; PMCID: PMC8455477.

Disclaimer

Disease diagnosis and treatment should always be performed by a veterinarian. The following information is for educational purposes only.