A Novel Locus for Familial Migraine on Xp22

Introduction.- Migraine is thought to be genetically complex. There is evidence of an X-linked dominant genetic component. A locus at Xq24-q28 has already been described supporting this hypothesis. Methods.- The X chromosome in 61 migraine families was screened using markers spanning the entire chromosome. Alleles were assigned using the GeneScan Analysis software, analysis for affected relative allele sharing and linkage was performed using Genehunter X and ALLEGRO. For linkage analysis we chose a model based on epidemiological data as well as assumptions drawn on other complex disorders. Results.- Linkage analysis of combined families showed a parametric 2-point logarithm of the odds (LOD) of 2.86 at theta 0.1 between markers DXS8051 and DXS1223, as well as excess allele sharing at marker DXS8051 with a non-parametric LOD score of 2.85. Conclusion.- These results provide suggestive evidence for a susceptibility locus for migraine on Xp22. Families with different types of migraine contributed to this LOD score.