GLUT1 Deficiency Syndrome and the Ketogenic Dietary Therapies

Abstract

AbstractIn the fed state, the human brain relies entirely on glucose for energy metabolism. Glucose entry into the brain is exclusively mediated by the facilitated glucose transporter protein type 1 (GLUT1). Impaired glucose transport into the brain resulting from GLUT1 deficiency will cause a cerebral “energy crisis,” particularly in the young, because the developing brain requires three to four times more energy than the adult brain. Clinical features of GLUT1 deficiency are global developmental delay, early-onset epilepsy, and a complex movement disorder. In suspected cases, a lumbar puncture should be performed in a metabolic steady state following a 4- to 6-hr fast. In GLUT1 deficiency, cerebrospinal fluid (CSF) glucose concentrations usually are < 50 mg/dl. GLUT1 deficiency is treatable only by means of a ketogenic diet, which provides ketone bodies as an alternative fuel for brain energy metabolism. The majority of patients with GLUT1 deficiency show immediate and continuing seizure control during ketogenic diet treatment.