Urinary Stones in Cats: What a 445-Cat Study Found About Genetics

Understanding stone risk—and three practical care tips to start today

 

Alex Shin, Pharmacist | Greycoat Research
5,000+ consultations with owners of cats with stage 2 or 3 chronic kidney disease
Nutritional Formulation Advisor

When you think about urinary stones in cats, food and water probably come to mind first.

But could your cat’s genes also play a role?

In one study, cats in one genetic group were more likely to have had stones than cats in another. Here’s what the researchers found—and three practical ways to help care for your cat.

Genes and Urinary Stones: What the Study Found

In a study published in 2022, researchers examined 445 cats at one research facility. They compared different forms of a gene called AGXT2 with the cats’ history of kidney or urinary tract stones.

A history of stones was about 2.5 times as common in the AA group as in the GG group. AA and GG describe different genetic types of AGXT2.

The finding links this genetic difference to stone history in that group of cats. It does not mean a cat with a particular genetic type will necessarily develop stones.

For cats that have stones, care depends on the stone type. Here, we’ll focus on calcium oxalate stones, one of the most common types in cats.

Calcium Oxalate Stones Cannot Be Dissolved With Diet

Calcium oxalate and struvite are two common types of urinary stones in cats. One important difference is whether a prescription diet can dissolve them.

Treatment for calcium oxalate stones depends on their size, location, and effect on urine flow. If removal is needed, it may involve surgery or another procedure under general anesthesia.

Kidney stones that are not causing problems may be monitored with imaging. However, a stone blocking a ureter—the tube carrying urine from a kidney to the bladder—can damage that kidney and needs prompt treatment.

Diet still matters for calcium oxalate stones. The right food and adequate water intake can help reduce the risk of new stones, alongside monitoring and any treatment needed for existing ones.

How Do Tiny Crystals Become Stones?

Calcium oxalate stones form when calcium and oxalate combine in urine. Oxalate comes from food and is also produced naturally in the body.

When urine becomes too concentrated, or calcium or oxalate levels in urine are high, tiny crystals can form more easily. Some remain in the urinary tract, where they may grow or clump together into stones.

That’s why ongoing care needs to address hydration, diet, and follow-up testing together.

Three Practical Ways to Care for Your Cat

Add Moisture to Meals

Getting enough water helps keep your cat’s urine from becoming overly concentrated.

If your cat eats a dry prescription diet, look for a wet formula designed for the same condition. You can also mix a little water into the food your cat already eats.

The key is to make sure your cat still eats well. If your cat eats less after you add water, use less water or try a suitable wet food with a texture they prefer.

Match the Food to the Stone Type

If your cat has calcium oxalate stones, check that the food is designed to help reduce the risk of new calcium oxalate stones. A general urinary health label does not tell you which stone types the food is designed to help manage.

If a removed stone has been analyzed, those results can help guide food choices. Crystals seen in a urine sample do not necessarily match the type of stone your cat has.

For calcium oxalate management, it is also important to avoid diets that make urine overly acidic. If your cat also has kidney disease, the food needs to support both their kidney health and stone management.

Know What to Look for in Test Results

Urine tests, blood tests, and imaging each provide different information. Here’s what to check when reviewing the results.

A urine sample without crystals does not rule out stones. If stones have already been found, follow-up imaging helps track changes over time.

At home, watch how often your cat visits the litter box and how much urine they actually pass. If your cat repeatedly strains to urinate but passes little or no urine, seek veterinary care immediately.

Could Vitamin B6 Help?

Vitamin B6 plays a role in how the body produces oxalate.

A human study examined 95 people with urinary stones and high levels of oxalate in their urine. In the group receiving both dietary counseling and B6 supplementation, the average amount of oxalate passed in urine each day fell by about 30%.

The study did not test B6 alone or its effects in cats.

For cats with recurring calcium oxalate stones, B6 supplementation may be considered as part of their care plan, based on their diet and test results.

Can You Learn More About Your Cat’s Genes?

The AIM Test provides your cat’s AIM gene results alongside information about genetic variants associated with urinary stones. AGXT2, the gene discussed earlier, and AIM are different genes.

These results help you understand your cat’s inherited traits. They do not diagnose existing stones or predict whether your cat will develop them. Urine tests, blood tests, and imaging provide information about your cat’s current health.

From Today’s Meal to the Next Checkup

At your cat’s next meal, try adding a little water and watch whether they still eat as usual. Check which stone types their food is designed to help manage. At the next checkup, compare the findings with previous results.

At Greycoat Research, we share clear explanations of feline kidney and urinary health research, along with practical care tips you can use at home.

About the Author and Research Team

Alex Shin is a pharmacist with more than 20 years of experience advising on medications for animals. His work includes consultations with owners of cats with kidney disease and advising on nutritional formulations.

Greycoat Research works with veterinarians, pharmacists, and researchers in Korea and Japan to study feline kidney health and nutrition.

 

Specializing in Feline Kidney Care
Greycoat Research

[Educational Disclaimer]

This content is provided for general educational and informational purposes only.
It is not intended as a substitute for professional veterinary advice, diagnosis, or treatment, nor is it intended to diagnose, treat, cure, or prevent any disease.
Please consult your veterinarian regarding your cat’s health and before making any changes to your cat’s diet, supplements, or care routine.