RT Journal Article SR Electronic T1 The inheritance of migraine with aura estimated by means of structural equation modelling JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 225 OP 227 DO 10.1136/jmg.36.3.225 VO 36 IS 3 A1 Vibeke Ulrich A1 Morten Gervil A1 Kirsten O Kyvik A1 Jes Olesen A1 Michael B Russell YR 1999 UL http://jmg.bmj.com/content/36/3/225.abstract AB Studies of migraine with aura (MA) have shown familial aggregation of the disorder, which cannot be explained by simple mendelian inheritance. The interest in a genetic basis for the disorder has increased after identification of three genetic loci for familial hemiplegic migraine (FHM), which is a rare subtype of MA with autosomal dominant inheritance. Both genetic and environmental factors seem to be important in the expression of MA. To elucidate the molecular pathogenesis of MA, knowledge of the relative role of genetic and environmental factors is essential. Twin studies are a classic way to analyse this. We applied structural equation modelling on MA with twin data obtained from a population based twin register in order to evaluate the effects of genes and environment. The correlation in liability of MA was 0.68 in monozygotic (MZ) and 0.22 in dizygotic (DZ) twin pairs, indicating a high degree of genetic determination in the total variance of liability. The best fitting model combined additive genetic effects and environmental effects that were not shared by the twins. The estimate of heritability was 0.65 and similar in males and females.