A Cyclooxygenase 2 Gene Polymorphism is a Risk Factor for the Complication of Medication Overuse Headaches in Patients with Migraines

Abstract

We determined whether cyclooxygenase-2 (COX-2) gene polymorphisms were involved in the aggravation of migraines due to the overuse of medication. Polymorphisms in the COX-2 (rs20417, rs689466) gene were examined. Forty-seven patients with migraine (6 males and 41 females; 5 with migraines with aura (MA), 36 with migraines without aura (MO), 6 with MA + MO; 1 with MA and 21 with MO; 36.4 ± 10.3 years) and 22 patients with medication overuse headache (MOH) (1 male and 21 females; 39.6 ± 9.9 years) who had migraines participated in this study. The genotypes of each polymorphism were analyzed by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) methods. No significant differences were observed in the genotypic distributions of rs20417 (C/C + G/C vs. G/G, p=0.220) between migraine patients and MOH patients. The frequencies of the rs689466 G/G genotype were significantly higher in patients with MOH than in patients with migraines (G/G vs. A/A+A/G, p=0.008). Furthermore, the frequencies of the rs689466 G/G genotype were significantly higher in patients with MOH who had migraines without aura (MO) than in patients with MO (G/G vs. A/A+A/G, p=0.001). The results of this study showed that the COX-2 polymorphism (rs689466) was independently related with the complication of MOH in patients with MO.