Inactivating or loss-of-function (LOF) mutations of major facilitated diffusion glucose transporter 1 (GLUT1) lead to GLUT1-deficiency syndrome (GLUT1-DS), an autosomal dominant haploinsufficiency disorder, which results in a low glucose concentration in the cerebrospinal fluid and therefore lack of energy supply to the brain (Rotstein et al. 2010; De Vivo et al. 1991). Here, SLC2A1 is linked to Dravet syndrome.