Results: All the cheetahs who were unaffected by hyperammonemia excreted high concentrations 3-aminopiperidine-2-one. This metabolite was almost absent in the urine of the cheetahs prone to hyperammonemia. Conclusions: These results may indicate that cheetahs may use 3aminopiperidine-2-one as a source for ornithine or that an increased catabolism of ornithine to glutamic acid may result in hyperammonemia. Background: Patients with organic acidurias (OADs) and urea cycle defects (UCDs) have an enormous need for improved medical awareness, optimization of the diagnostic process and therapy, and improved networking between healthcare professionals and patients. Methods: An initiative named "European registry and network for Intoxication type Metabolic Diseases (E-IMD)" funded by the European Commission through DG Sanco has been started in January 2011. E-IMD aims to promote health for patients with OADs and UCDs.