Health Screening Guide
HUU in French Bulldogs
Hyperuricosuria explained: what causes bladder stones in Frenchies, how to test for it, and how to breed safely to protect your puppies from this painful condition.
Check Your PairingWhat Is Hyperuricosuria (HUU)?
Hyperuricosuria, or HUU, is a hereditary metabolic disorder that affects how French Bulldogs process purines — compounds found in many proteins. Dogs with HUU cannot properly reabsorb uric acid from their urine, causing dangerously high concentrations that crystallize into bladder and kidney stones.
These stones are not just uncomfortable. They can cause urinary tract infections, blockages, and in severe cases, life-threatening uremia if the urinary tract is completely obstructed. Surgery to remove stones is expensive and painful for the dog.
HUU is caused by a mutation in the SLC2A9 gene. Like DM, it is recessive — a dog must inherit two mutated copies to be affected. The good news: genetic testing makes HUU 100% preventable in breeding programs.
HUU Genotypes Explained
Understanding your dog's HUU genotype is the first step to safe breeding. Here is what each result means.
N / NClearNo HUU mutation. Safe to breed to any partner without producing affected puppies.
N / HUUCarrierCarries one mutated copy. Healthy, but can pass HUU to 50% of offspring.
HUU / HUUAffectedTwo mutated copies. Will produce excessive uric acid and form bladder stones.
Safe HUU Breeding Pairings
N/N x N/N100% clear puppies
N/N x N/HUU50% clear, 50% carriers — no affected puppies
N/HUU x N/HUU25% affected, 50% carriers, 25% clear — AVOID
N/HUU x HUU/HUU50% affected, 50% carriers — NEVER BREED
Managing HUU in Affected Dogs
If you already own a Frenchie that is affected by HUU (HUU/HUU), all is not lost. With proper management, many affected dogs live comfortable, happy lives. The key is controlling uric acid levels through diet, hydration, and medication.
Low-Purine Diet
Feed foods low in organ meats, fish, and high-purine proteins. Prescription urinary diets are available from your veterinarian.
Constant Hydration
Encourage drinking with multiple water bowls, pet fountains, and wet food. Diluted urine prevents crystal formation.
Urine Alkalinizers
Medications like potassium citrate raise urine pH, which dissolves uric acid crystals before they form stones.
Regular Monitoring
Schedule periodic urinalysis and ultrasound exams to catch stones early before they cause blockages.
Prevent HUU Before It Starts
Our DNA Calculator checks HUU, DM, JHC, and CMR1 simultaneously. Know every health risk your pairing produces before you breed.
Open the DNA CalculatorFrequently Asked Questions
What is HUU in French Bulldogs?
Hyperuricosuria (HUU) is a genetic condition that causes French Bulldogs to produce excessive uric acid in their urine. This leads to the formation of painful bladder and kidney stones. HUU is caused by a mutation in the SLC2A9 gene and is inherited in an autosomal recessive pattern.
How is HUU inherited in Frenchies?
HUU is a recessive trait. A dog must have two copies of the mutated SLC2A9 gene (HUU/HUU) to be affected and form stones. Dogs with one copy (N/HUU) are carriers — they appear healthy but pass the mutation to approximately 50% of their offspring. Clear dogs (N/N) cannot pass HUU on.
What are the symptoms of HUU in French Bulldogs?
Symptoms include frequent urination, straining to urinate, blood in the urine, painful urination, and recurrent urinary tract infections. In severe cases, a stone can block the urinary tract completely, which is a life-threatening emergency requiring immediate veterinary care.
Can HUU be treated or managed?
Yes, but not cured. Affected dogs require lifelong management with a low-purine diet, increased water intake, and medications to alkalinize urine. Some stones must be surgically removed. Prevention through genetic testing before breeding is far more effective than treatment.
Should I breed a Frenchie that is an HUU carrier?
Carriers can be bred, but only to a clear (N/N) partner. This pairing produces 50% carriers and 50% clear puppies — no affected puppies. Never breed two carriers together, as that creates a 25% chance of producing affected (HUU/HUU) puppies who will suffer from stones.
How do I test my Frenchie for HUU?
Order a DNA health panel from Embark, Animal Genetics, or DDC. HUU testing is included in most standard French Bulldog health panels. You will receive a genotype result for the SLC2A9 gene within 2 to 4 weeks.