CACNA1A gene polymorphisms in cluster headache.

Cluster headache (CH) is a primary headache disorder where the aetiological and pathophysiological mechanisms still are largely unknown. An increased risk of CH in first- and second-degree relatives suggests the importance of genetic factors. Mutations of the P/Q type calcium channel alpha 1 subunit (CACNA1A) gene on chromosome 19p13 have been shown to cause several neurological disorders with a wide clinical spectrum, mainly episodic diseases. Missense mutations of the gene cause familial hemiplegic migraine (FHM) and it is also likely to be involved in the more common forms of migraine. The CACNA1A gene is thus a promising candidate gene for CH. In this study we performed an association analysis of an intragenic polymorphic (CA)n-repeat with marker D19S1150 and a (CAG)n-repeat in the 3'UTR region, in 75 patients with CH according to IHS criteria and 108 matched controls. Genotypes and allele frequencies were similarly distributed in patients and controls. Linkage disequilibrium between the two markers was similar in patients and controls. We conclude that an importance of the CACNA1A gene in sporadic CH is unlikely.