Genetic factors in cluster headache.

Genetic factors are likely to play a role in cluster headache but are not simply accounted for. A small number of family studies have illustrated the role of genetics, and a few inconclusive studies assessed candidate genes for cluster headache. These clinical genetic studies are reviewed and the author's results from a large database of cluster headache patients are reported. The importance of genetic factors in cluster headache pathophysiology and comment on difficulties in genetic research of cluster headache are discussed.