During the migraine attack, plasma neuropeptide Y (NPY) [17] and endothelin-1 (ET-1) level [18] are significantly increased relative to the levels in healthy individuals, while during the headache-free periods, the ET-1 level is significantly increased relative to the level in healthy individuals [18] and the plasma NPY level [19] is not significantly altered. The gene discussed is NPY; the disease is Headache.