Glucose Transporter 1 Deficiency Syndrome (GLUT1-DS; OMIM #606777) is a rare disease caused by dominant mutations in SLC2A1 encoding GLUT1, which is a ubiquitous transporter of glucose across plasma membranes, particularly across the blood-brain barrier. Hypoglycorrhachia symptoms are the cornerstones of GLUT1-DS, but delayed growth has also been suggested. This led us to investigate, at diagnosis, the relationship between the glycemia/glycorrhachia ratio and the nutritional and growth pattern phenotype of 30 GLUT-DS patients.