Galimberti et al. performed an association study in which they analyzed the correlation between progranulin gene variations and the risk for developing BD in patients with BD-I and BD-II (Galimberti et al., 2012, 2014): the specific GRN SNP rs5848, which is associated with variation in progranulin levels (Galimberti et al., 2014), resulted to be a protective factor associated with BD-I, but not with BD-II, probably due to different pathogenic mechanisms among the two subtypes of diseases. The gene discussed is GRN; the disease is Behcet disease.