The disease was first described by Blau in 1985 [2], and then a similar family was reported by Jabs et al. [3] in the same year. Mutations in NOD2/CARD15 (nucleotide-binding oligomerization domain containing 2/caspase recruitment domain family, member 15) were first identified to be associated with susceptibility to Crohn's disease (CD) [4], which improved our knowledge of systemic autoinflammatory disorders. The gene discussed is NOD2; the disease is Crohn disease.