Several migraine susceptibility and treatment response genes, including SLC6A4, code for serotonin transporter and influence serotonin reuptake, and COMT, which encodes for catechol-O-methyltransferase, affecting the degradation of catecholamines interact with the serotonin system and the HTR1B receptor [8]. The gene discussed is COMT; the disease is migraine disorder.