Abstract
Genetic epidemiological studies indicate that both migraine and cluster headache have a genetic component (1–4). Migraine without aura and migraine with aura are likely to have multifactorial inheritance, while cluster headache is likely to have an autosomal dominant mode of inheritance in some families (5, 6). Both cluster headache and migraine are paroxysmal disorders, each with a distinct attack pattern. Episodic cluster headache is characterized by attacks every other day to 8 per day in a cluster period, followed by a period without attacks varying from few months to years. Migraine without aura and migraine with aura are characterized by a single attack recurring with intervals of days to months/years. Onset of cluster headache is generally later than onset of migraine without aura and migraine with aura. Cluster headache and migraine has been described to be associated. However, the 12.8% frequency of migraine among people with cluster headache (7–15), corresponds with the prevalence of migraine in the general population. Thus, from an genetic epidemiological point of view, it is unlikely that migraine and cluster headache are associated. This is in accordance with the paper by Haan et al. in this issue of Cephalalgia which shows the lack of involvement of the CACNA1A gene in a Dutch cluster headache family with three affected.