Due to increasing numbers of HUU (SLC2A9) mutation carriers being highlighted the Kennel Club were approached to add the HUU DNA test to the official DNA testing scheme, in order to facilitate monitoring of the mutation frequency. However an association between dogs having symptoms and being genetically affected was required.

The Giant Schnauzer Health Fund, in collaboration with the Kennel Club, Cambridge University, Idexx laboratory, and the Royal Veterinary College agreed to undertake a study in the Giant Schnauzer, in an to attempt to validate the HUU mutation SLC2A9 as a causation for bladder/kidney stones (purine type) in the breed. The goal being to enable the HUU test to become part of the official Kennel Club DNA testing scheme, enabling results to be officially recorded via the KC health database.

The study aims to collect urine samples from Giant Schnauzers already DNA tested for the HUU SLC2A9 mutation; 5 genetically clear, 5 carriers and 5 affected. It was arranged for Idexx to test the uric acid:creatinine ratio of submitted urine samples; any affected dogs already on a low purine diet would be required to follow a period of at least 5 days on a normal balanced diet before collecting a urine sample, in order to prevent interference with the result. Prior to the urine collection, dogs were required to be starved from 6pm the previous day, and urine collected first thing in the morning before any food or water.

The GSHF were already aware of 5 clear, 4 carriers and an effected Giant in the UK, and at least 3 affected in Germany. Urine samples obtained were to be returned to the Kennel Club.

Update 21/04/2023
To date samples have been returned from 4 clear, 4 carriers and 1 affected
Sample kits sent to Germany were having problems getting through customs

Update 11/12/2023
To date samples have been returned from 5 clear, 4 carriers and 1 affected

Due to problems sending international sample kits through customs, affected dogs in Germany and USA were provided with details, as an option, to have sample collections via their own veterinary clinics. Sadly one affected dog had since passed away.

Update 19/06/2025
The Kennel Club officially approved the DNA testing scheme for hyperuricosuria (HUU) in the Giant Schnauzer, and also added the test to the Breed Health Standard ‘Best Practice’.