In canine inflammatory bowel disease, one of the most challenging pathologies in gastroenterology, polymorphisms in the toll-like receptors 5 [128] and 4 [129] genes are believed to have a significant contribution as well as the major histocompatibility complex class II locus (dog leukocyte antigen) [130], specifically in German shepherds. The gene discussed is TLR5; the disease is inflammatory bowel disease.