title: Clinical characteristics of migraine concordant monozygotic twin pairs.
abstract: OBJECTIVE
  The aim of the study was to search for clinical differences between migraine with and without aura.
  
  
  METHODS
  From a population-based Finnish Twin Cohort we studied 51 migraine concordant monozygotic twin pairs.
  
  
  RESULTS
  There were 20 pairs concordant for migraine with aura, 6 pairs concordant for migraine without aura and 12 "mixed" pairs. In the remaining 13 pairs the aura of at least 1 twin could not be classified. All 20 migraine with aura pairs were concordant for visual aura and 19 for moderate or severe headache while all 6 pairs with migraine without aura were concordant for headache duration of 4 to 24 h, moderate or severe headache and nausea. The 12 "mixed" pairs had more often unilateral and pulsating headache compared to both the migraine with or without aura pairs. Overall individual migraine with aura twins had more photophobia (P = 0.032) and the migraine without aura twins more nausea (P = 0.025).
  
  
  CONCLUSIONS
  The difference between migraine with and without aura is not explained entirely by genetical factors: 12 genetically identical twin pairs were discordant for the aura. The headache phase in migraine with and without aura is very similar, but not identical. Probably there are several and different liability loci for the migraine aura and the migraine headache. The distribution of these several loci along with acquired factors will decide whether the phenotype is migraine with or without aura.
authors.affiliation: Department of Neurology, University of Helsinki, Finland.
authors.forename: M
authors.initials: M
authors.lastname: Kallela
authors.forename: M
authors.initials: M
authors.lastname: Wessman
authors.forename: M
authors.initials: M
authors.lastname: Färkkilä
authors.forename: A
authors.initials: A
authors.lastname: Palotie
authors.forename: M
authors.initials: M
authors.lastname: Koskenvuo
authors.forename: M L
authors.initials: ML
authors.lastname: Honkasalo
authors.forename: J
authors.initials: J
authors.lastname: Kaprio
mesh_terms: D000328:Adult; D000368:Aged; D004200:Diseases in Twins / Q000235:genetics*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000235:genetics*; D011795:Surveys and Questionnaires; D014430:Twins, Monozygotic