Increased familial risk of cluster headache

The authors studied the occurrence of cluster headache in the families of 2 20 Italian patients with cluster headache. A positive family history was fo und in 20% (44/220) of the families. Compared with the general population, first-degree relatives had a 39-fold significantly increased risk of cluste r headache. Second-degree relatives had an eightfold significantly increase d risk. The increased familial risk strongly supports the hypothesis that c luster headache has a genetic component in some families.