Title

Chronic migraine: Genetics or environment?
January 11, 2021
Citation: Eur J Neurol. 2021 Jan 11 [Epub ahead of print]

BACKGROUND The transition from episodic migraine to chronic migraine, migraine chronification, is usually a gradual process, which involves multiple risk factors. To date, studies of the genetic risk factors for chronic migraine have focused primarily on candidate gene approaches using healthy individuals as controls.
AIMS/METHODS In this study, we use a large cohort of migraine families and unrelated migraine patients (n>2200) with supporting genotype and whole genome sequencing data. We evaluate whether there are any genetic variants, common or rare, with specific association to chronic migraine compared with episodic migraine.
RESULTS We find no aggregation of chronic migraine in families with a clustering of migraine. No specific rare variants give rise to migraine chronification, and migraine chronification is not associated with a higher polygenic risk score. Migraine chronification is not associated with allelic associations with an odds ratio above 2.65. Assessment of effect sizes with genome-wide significance below an odds ratio of 2.65 requires a genome-wide association study of at least 7500 chronic migraine patients.
CONCLUSION Our results suggest that migraine chronification is caused by environmental factors rather than genetic factors.