2,8-dihydroxyadenine urolithiasis / APRT deficiency (APRT c.260G>A) - Dog

What does this test examine?

This genetic test examines the APRT variant c.260G>A in dogs. The variant causes 2,8-dihydroxyadenine urolithiasis, also known as 2,8-DHA urolithiasis, DHA urinary stones, 2,8-dihydroxyadeninuria, APRT deficiency, adenine phosphoribosyltransferase deficiency or an inherited purine metabolism disorder.

In this disorder, 2,8-dihydroxyadenine accumulates in urine. This compound has low solubility, so crystals and stones can form in the bladder, urinary tract or kidneys. The condition is rare, but the consequences can be serious because urinary stones and crystal deposits can cause irritation, obstruction and kidney damage.

What does APRT deficiency mean?

APRT is an enzyme in purine metabolism. When APRT does not function sufficiently, adenine is converted through another pathway into 2,8-dihydroxyadenine. Because 2,8-DHA dissolves poorly in urine, it can precipitate as crystals or urinary stones. Genetically affected dogs can therefore develop straining to urinate, frequent urination, urgency, blood in urine, abdominal pain, recurrent urinary problems or life-threatening urinary obstruction.

Stones can occur in the bladder or kidneys. Microscopic crystals can also accumulate in kidney tissue and contribute to kidney disease. Some dogs show clear signs, while others initially have few or no visible symptoms. This is why genetic testing is valuable: it can identify inherited risk before stones or kidney damage become obvious.

Inheritance and result

This trait is inherited as autosomal recessive. A dog with two normal copies is clear for the tested variant. A dog with one copy is a carrier: usually without clinical signs, but important for breeding. A dog with two copies is genetically affected; this genotype causes the tested APRT-related form of 2,8-DHA urolithiasis.

The result labels are GG, GA and AA. The A allele is the tested disease variant.

Practical value of this test

This test gives breeders, owners and veterinarians early insight into an inherited risk that may otherwise only become visible once urinary problems or stones are already present. The result supports better breeding decisions, carrier detection and timely follow-up of genetically affected dogs.

Why test?

• Distinguishes clear, carrier and genetically affected dogs.
• Helps avoid carrier-to-carrier matings and prevent affected puppies.
• Supports targeted screening of relatives when a carrier or affected dog is found.
• Provides useful information in dogs with recurrent urinary signs, crystals or unexplained urinary stones.
• Helps plan early attention to water intake, diet, urine monitoring and follow-up in dogs with genetic risk.