This is an example of guanylate cyclase-C agonist (Busby et al., 2013), which has been shown to reduce visceral hypersensitivity in preclinical studies and to improve abdominal pain and constipation symptoms in phase 2 and 3 clinical trials of patients with IBS and constipation (Johnston et al., 2013). This evidence concerns the gene NPR3 and irritable bowel syndrome.