Classic Glucose Transporter Type 1 Deficiency Syndrome, also known as encephalopathy due to glut1 deficiency, is related to glucose transporter type 1 deficiency syndrome and glut1 deficiency syndrome 1. An important gene associated with Classic Glucose Transporter Type 1 Deficiency Syndrome is SLC2A1 (Solute Carrier Family 2 Member 1). Affiliated tissues include eye and brain, and related phenotypes are seizure and spasticity