Many vasoactive neuropeptides such as substance P, neurokinin A [22] calcitonin gene–related peptide [23], NO [24] and serotonin [25] have been hypothesized in migraine pathology and these same molecules can play a role in photophobia, phonophobia, nausea, vomiting, numbness and generalized tiredness/weakness. The gene discussed is TAC1; the disease is migraine disorder.