NOD2 and Blau syndrome: By analysis of nine types of NOD2 mutations collected from 20 Japanese Blau syndrome patients, the basal NF-κB activity level, which was presented as a ratio of the NF-κB activity in the absence of MDP to that in the presence of MDP, was shown to range from 0.3 for the E383G mutation to 0.9 for the N670K mutation, compared to 0.05 for the wild-type [12].