SLC6A4 and migraine disorder: The disturbances in serotonergic and hypocretinergic systems in migraine may be a consequence of polymorphisms in genes, such as SLC6A4 and HCRTR1. For the genetic studies we chose 5-HTTLPR polymorphism of SLC6A4 and G1222A, *G29A SNP of HCRTR1. We found no association between 5-HTTLPR and migraine.