Abstracts

Rationale: Glucose transporter type 1 deficiency syndrome (GLUT-1 DS) is an epileptic encephalopathy caused by a mutation in GLUT-1 gene, resulting in impaired glucose transport into the brain. Patients suffer from varying levels of epilepsy, spasticity, dysarthria, microcephaly, movement disorders and learning disabilities. Biochemically, hypoglycorrhachia is a hallmark of the syndrome. So far, only visual assessment of FDG-images has been performed (Pascual et al., 2002).Methods: We evaluated the glucose metabolism in the brain of 13 patients (6 men, 7 women; 15-53 years old) with a mutation in GLUT-1 gene using FDG-PET. Patients were evaluated by SPM comparison to 20 healthy, age-matched controls (p_height < 0.001 uncorrected).Results: In patients with GLUT-1 DS, average glycorrhachia was 42.9 mg/dl, which is significantly lower than the normal range of 50-80 mg/dl (p < 0.001). Categorical SPM analysis showed a bilateral decrease in glucose metabolism in the thalamus, anterior cingulate cortex and overlying midfrontal and midparietal cortex and a bilateral increase in the putamen. Abnormalities in the cortical regions were positively correlated to glycorrhachia. There was no correlation with age in the regions of abnormal glucose metabolism.Conclusions: Voxel-based analysis of glucose metabolism in patients with a mild phenotype of GLUT-1 DS shows regionally differing metabolic changes, which are probably caused by an insufficient glucose availability during early brain development, as they are present from infancy and do not change with ageing. Cortical abnormalities are more pronounced when glycorrhachia is lower, representing a more severe phenotype of GLUT-1 DS.