Cystinuria type B / cystine stones 3 variants (SLC7A9-related) - Cat

Cystinuria and cystine stones

This genetic test analyses variants in SLC7A9 that can cause cystinuria in cats. Cystinuria is an inherited metabolic disorder in which cystine and related amino acids are not reabsorbed efficiently. Cystine can then accumulate in the urine and form crystals or stones in the bladder and urinary tract.

Cats with cystine stones may show painful or difficult urination, small volumes of urine, blood in the urine or urinary obstruction. Obstruction is especially important because rapid action may be needed.

Practical value of this test

• Determines whether the cat is clear, a carrier or genetically affected for the tested variant.
• Helps breeders avoid risk combinations and follow carriers more deliberately.
• Provides clear genetic information in cats with cystine crystals, cystine stones or recurrent urinary signs.

The result should be interpreted per tested variant. In type B cystinuria the inheritance classification is more complex than in classic type I-A cystinuria, but two copies of the involved SLC7A9 variant have been described in affected cats.