SLC7A9 and cystinuria: Moreover, very few (between 0–1.5% depending on the breed) English or French Bulldogs, American Staffordshire Terriers, Golden Retrievers or mixed breed dogs at putative genetic risk due to their SLC3A1 and SLC7A9 genotypes showed clinical signs (EMR-documented cystic calculi, crystalluria, hematuria, urolithiasis, nephrolithiasis, urinary tract infection or cystitis) supporting a diagnosis of cystinuria.