Taken together, the study’s main findings were that serum Orexin-A, HIF-1, VEGF and Endothelin-1 at sea level was more in AMS-resistant individuals, and all of them increased after exposure to altitude in No-AMS and AMS+; however, the magnitude of the Orexin-A response to the altitude at 1 and 24 h after exposure to hypoxia in individuals with AMS+ was approximately identical with No-AMS group. This evidence concerns the gene EDN1 and ablepharon macrostomia syndrome.