NOD1 and Crohn disease: At the amino acid level: changes in NOD2 can lead to an increased susceptibility to inflammatory disorders such as Crohn’s disease or cause conditions like Blau Syndrome (8–10); variation in the LRR of NOD1 explains the preferential recognition of tripeptide and tetrapeptide diaminopimelic acid containing peptidoglycan fragments by human and murine NOD1 respectively (11, 12); the C-terminus of NOD2 is important for membrane localization (13); and that specific patches are involved in RIP2 interaction (14, 15), Ubiquitin binding (16), and nucleotide binding and hydrolysis (7).