title: Genetic Contribution of Catechol-O-methyltransferase Polymorphism in Patients with Migraine without Aura.
abstract: BACKGROUND
  Recent genetic association studies have investigated the possible genetic role of the dopaminergic system in migraine. Catechol-O-methyltransferase (COMT) is an enzyme that plays a crucial role in the metabolism of dopamine and its genetic polymorphism is associated with three- to fourfold variation of enzymatic activity.
  
  
  OBJECTIVE
  The objective of this study was to elucidate the role of the COMT polymorphism in the genetic susceptibility to migraine and its phenotypic expression in patients with migraine without aura (MWOA).
  
  
  METHODS
  Ninety-seven patients with MWOA and 94 healthy volunteers were included in the study. After amplifying COMT genes by the polymerase chain reaction, we assessed their genotype frequencies and allele distributions by based on restriction fragment length polymorphisms. We classified all MWOA patients into two groups according to their COMT genotype: with the L allele (N = 43), and without this allele (N = 54).
  
  
  RESULTS
  The genotype frequency and allele distribution of the COMT polymorphism did not differ between MWOA patients and the control group. During migraine attacks, MWOA patients with the L allele showed a higher pain intensity of headache (P = 0.001) and a higher incidence of the accompanying nausea/vomiting (94% vs 75%; P = 0.026) compared with MWOA patients without the L allele.
  
  
  CONCLUSIONS
  Although the COMT polymorphism does not appear to be involved in predisposition to the development of MWOA, this genetic factor could be involved in the phenotypic expression of MWOA.
authors.affiliation: Department of Neurology, College of Medicine, The Catholic University of Korea, Seoul, Korea.
authors.forename: Jeong Wook
authors.initials: JW
authors.lastname: Park
authors.forename: Kwang Soo
authors.initials: KS
authors.lastname: Lee
authors.forename: Joong Seok
authors.initials: JS
authors.lastname: Kim
authors.forename: Yeong In
authors.initials: YI
authors.lastname: Kim
authors.forename: Hae Eun
authors.initials: HE
authors.lastname: Shin