Apolipoprotein E gene polymorphisms in patients with migraine.

To investigate the role of apolipoprotein E (APOE) polymorphisms in migraine, we analyzed the APOE genotypes of 241 migraine patients and 587 controls. The results of a Chi-square analysis indicated that APOE alleles were similarly distributed (chi(2)=2.89, P=0.24) between cases and controls. However, we found a significant (P<0.001) increase of the varepsilon2-varepsilon4 genotype in the group of migraine patients. Patients were divided into three subgroups: migraine with aura; migraine without aura; and mixed headaches (migraine associated with tension-type headache). Subgroup analysis showed that the varepsilon2-varepsilon4 genotype was significantly increased only in patients with mixed headaches. The stratification of patients by APOE status did not reveal significant associations with the clinical features of the disease. In conclusion, we observed no significant association between APOE polymorphisms and migraine. The association between the APOE varepsilon2-varepsilon4 genotype and the tension-type headache deserves further evaluation.