Intractable seizures, developmental delay, and the ketogenic diet.

Glucose transporter type 1 (GLUT1) deficiency syndrome is a rare, treatable cause of developmental delay and seizures. It must be considered in the differential diagnosis of infants with intractable seizures. The finding of a low glucose level in the cerebrospinal fluid with normal level in the blood in the absence of pleocytosis or other cerebrospinal fluid abnormalities identifies the condition.