SLC2A1 and infantile-onset epilepsy: More often, as in the case of the germline Slc2A1 gene mutation (haplodeficiency), infantile-onset epilepsy with persistently low cerebrospinal fluid glucose concentrations, delayed development, microcephaly with intellectual disability, and complex movement difficulties which include gait abnormalities are encountered and referred to as GLUT1 deficiency syndrome [133,134].