In this context, it merits emphasis that intravenous infusion of PACAP-38 elicits migraine attacks in people with migraine, while healthy individuals experience mild or no headache.12 Furthermore, recent phase II results demonstrated the effectiveness of a monoclonal antibody (mAb) against PACAP signalling for migraine prevention.13 If it is confirmed that PACAP-38 can indeed induce migraine-like headache in people with PTH, this will bolster the concept of targeting PACAP signalling. This evidence concerns the gene ADCYAP1 and Headache.