Glucose Transporter 1 Deficiency as a Treatable Cause of Myoclonic Astatic Epilepsy

Objective: To determine if a significant proportion of patients with myoclonic-asta tic epilepsy (MAE) have glucose transporter 1 (GLUT1) deficiency. Design: Genetic analysis. Setting: Ambulatory and hospitalized care. Patients: Eighty-four unrelated probands with MAE were phenotyped and SLC2A1 was sequenced and analyzed by multiplex ligation-dependent probe amplification. Any identified mutations were then screened in controls. Main Outcome Measure: Any SLC2A1 mutations. Results: Four of 84 probands with MAE had a mutation of SLC2A1 on sequencing. Multiplex ligation-dependent probe amplification analysis did not reveal any genomic rearrangements in 75 of the remaining cases; 5 could not be tested. Two patients with MAE with SLC2A1 mutations also developed paroxysmal exertional dyskinesia in childhood. Conclusions: Five percent of our patients with MAE had SLC2A1 mutations, suggesting that patients with MAE should be tested for GLUT1 deficiency. Diagnosis of GLUT1 deficiency is a strong indication for early use of the ketogenic diet, which may substantially improve outcome of this severe disorder.