Lack of association of endothelial nitric oxide synthase polymorphisms and migraine.

Objective: The aim of this study was to evaluate if 2 functional endothelial nitric oxide synthase (eNOS) gene polymorphisms might be risk factors for migraine.

Background: Nitric oxide synthase promotes the synthesis of nitric oxide (NO). NO is a potent vasodilator and mediates several processes involved in migraine pathophysiology. Only one study has suggested an association with migraine with aura.

Methods: We performed a sex- and age-matched case-control study using 2 eNOS polymorphisms (rs1800779 and rs1799983), which are in linkage disequilibrium. Genotypes were obtained with allele-specific probes in a real-time polymerase chain reaction assay. Genotypic and allelic distributions were compared with chi(2) method. We also estimated the reconstructed haplotypes and calculated ORs for individual haplotypes.

Results: A total of 337 migraine patients (188 with aura) and 341 healthy controls were recruited. We found no significant differences in the distribution of genotypes and alleles for either polymorphism among clinical subgroups. Neither rs1800779 nor rs1799983 polymorphisms increased the risk for suffering from migraine aura.

Conclusions: As others have previously reported, we failed to demonstrate genetic association of the eNOS gene with migraine.