NOS3 and migraine disorder: In addition, a trend of association was indicated between NOS3 rs1799983 variant T allele and longer attack duration (>24 h); homozygous and heterozygous carriers of the rs1050450 variant T allele (62.5 vs. 37.5%) seem to experience migraine attacks longer than 24 h as compared to homozygous for the more common G allele [G vs. T: OR 1.481 (0.941–2.332), p = 0.089; GG vs. GT + TT: ORadj 1.731 (0.910–3.291), padj = 0.094] (Table 7).