Although accordingly with most prior studies, no significant association between migraine susceptibility and rs1799983 variant was observed in the overall SEC population of the current study, subgroup analysis demonstrated that homozygosity for the more common G allele of the rs1799983 variant in the NOS3 gene seems to be associated with remarkably increased migraine susceptibility in the male population of the current study; thus, NOS3 rs1799983 may serve as an independent risk factor for migraine susceptibility in male population. The gene discussed is NOS3; the disease is migraine disorder.