A study by Lance and Hinterberger [25] on the relationship between subtype of catecholamines and PHEO symptoms concluded that headaches did not have any relationship to the ratio of NE to E. Another hypothesis on the pathogenesis of headaches in PPGLs is the secretion of other vasoactive peptides by PPGLs, including adrenomedullin and calcitonin gene-related peptide, both of which could have a causative role in episodic vascular headaches [20, 26]. The gene discussed is ADM; the disease is Headache.