NOD2 and Blau syndrome: While mutations in the LRR impairing MDP-dependent NF-κB activation are reportedly associated with Crohn’s disease (CD), Blau syndrome-associated NOD2 variants are localized in the NOD and show increased MDP-independent basal NF-κB activation, which is measured by an in vitro reporter assay using HEK293 cells [3,9,10,11].