Indeed, if on one hand, preclinical evidence failed to demonstrate the role of PAC1 receptors in mast cell degranulation, on the other hand, the MrgB3 receptor, corresponding in humans to MRGX2 receptor, seems to have a role, in particular in the long-lasting flushing and in delayed migraine attacks observed after PACAP38 infusion in humans [41]. The gene discussed is ADCYAP1; the disease is migraine disorder.