Canine Cystinuria | Animal Genetics


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Canine Cystinuria


Canine Cystinuria is an autosomal recessive disorder that affects a dog's ability to filter cystine out of urine. Normally, tubules in the kidney are responsible for re-absorption of cystine, filtering it out of the urine. In dogs with Canine Cystinuria, the tubules are unable to transport the cystine, allowing it to accumulate in the urine. Cystine is generally insoluble in the acidic conditions of canine urine, allowing it to crystallize and form caliculi, also known as stones.

Not every dog that has the mutation responsible for Cystinuria will exhibit symptoms. Stones causing inflammation and blockage are often more common in males, due to their long, narrow urethra. Females exhibit symptoms much less frequently and may be completely asymptomatic.

Canine Cystinuria affects over 60 breeds of dogs. Research suggests that Newfoundlands carry a more severe form of this disease than other breeds. In a variety of breeds affected by Canine Cystinuria, symptoms are often not experienced until about 4-5 years in age. However, Newfoundlands may begin experiencing problems as early as 6 months to one year of age. Newfoundlands are much more likely to experience recurring urethral blockages that could require surgical intervention.

In the Newfoundland breed, the cause of Cystinuria is a single nucleotide polymorphism that occurs in the SLC3A1 gene which causes a premature stop codon. Cystinuria is a recessive disorder, meaning that the dog must have two copies of the defective gene to suffer from the disease. Because Cystinuria is a recessive disorder, a dog can also be a carrier of this disease, meaning it carries one copy of the mutation but does not display any symptoms. A carrier dog can pass on this mutation to their offspring and if they mate with another carrier dog, can produce offspring affected by Cystinuria.

Sample Type:


Test Is Relevant to the Following Breeds:

Landseer, Newfoundland


Animal Genetics offers DNA testing for Canine Cystinuria. The genetic test verifies the presence of the recessive CY gene and presents results as one of the following:

CY/CY Affected The dog carries two copies of the mutant gene and is homozygous for Cystinuria. The dog is affected by Canine Cystinuria.
CY/n Carrier Both the normal and mutant copies of the gene detected. The dog is a carrier for Canine Cystinuria.
n/nClear Dog tested negative for the Cystinuria gene mutation, and will not pass on the defective gene to its offspring.