Seizure Characterization and Electroencephalographic Features in Glut‐1 Deficiency Syndrome

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Abstract
Summary: Purpose:To characterize seizure types and electroencephalographic features of glucose transporter type 1 deficiency syndrome (Glut‐1 DS).Methods:Twenty children with clinical and laboratory features of Glut‐1 DS were evaluated. Age at seizure diagnosis, seizure classification, and response to treatment were determined by chart review. Thirty‐two continuous 24‐h EEG monitoring sessions and reports of 42 routine EEG studies were assessed.Results:Age at seizure diagnosis was between 4 weeks and 18 months (mean, 5 months). Seizure types were generalized tonic or clonic(14), absence(10), partial (nine), myoclonic (six), or astatic (four). During 24‐h EEGs, background activity showed generalized 2.5‐ to 4‐Hz spike–wave discharges (41%), generalized slowing or attenuation (34%), no abnormalities (34%), focal epileptiform discharges (13%), or focal slowing or attenuation (9%). No seizures were captured during 69% of the studies; the remainder had absence (19%), myoclonic (9%), or partial seizures (3%). On evaluation of routine and 24‐h EEG studies, focal epileptiform discharges (24%) and slowing (11%) were more frequent in ages 0–24 months. In older children (2–8 years), generalized epileptiform discharges (37.5%) and slowing (21%) were more common.Conclusions:In all ages, a normal interictal EEG was the most common EEG finding. When abnormalities occurred, focal slowing or epileptiform discharges were more prevalent in the infant. In older children (2 years or older), a generalized 2.5‐ to 4‐Hz spike–wave pattern emerged. Seizure types observed included, absence, myoclonic, partial, and astatic.