While SLC3A1 variants were observed in a previously reported cat (Type IA; p.Arg448Trp) and cause a recessively inherited cystinuria in 4 different canine breeds (Labrador Retrievers, Scottish Terriers, Newfoundlands and Landseers) (Type IA; p.Arg196*, p.Gly117Alafs*41) and a semi-dominant type (Type IIA; p.Thr366_Thr367del) cystinuria in Australian Cattle dogs, only one canine breed with an SLC7A9 variant has been reported to date. This evidence concerns the gene SLC3A1 and cystinuria.