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Introduction: Early onset absence epilepsy (EOAE) constitutes an idiopathic generalized epilepsy syndrome with typical absences starting before the age of four years. Mutations in SLC2A1, encoding the glucose transporter of the blood-brain barrier (GLUT-1), account for approximately 10% of EOAE cases. The role of SLC2A1 mutations in absence epilepsies with a later onset has not been assessed so far. Therefore, we aimed to compare the role of SLC2A1 mutations in EOAE and Childhood and Juvenile Absence Epilepsy (CAE, JAE). Method: 26 cases with EOAE and 40 probands with CAE or JAE were screened for SCL2A1 mutations by sequence analysis. Extensive phenotyping was performed in patients and family members. Results: Mutations in SLC2A1 were detected in 2/26 EOAE patients and 0/40 patients with familial absence epilepsy. One EOAE patient with a mild phenotype had a variant in exon 8 (c.1008G>C) leading to an amino acid exchange (336Leu>Val), the family history was unremarkable. The other EOAE patient with a very early onset of a severe epilepsy phenotype and movement disorder had a base exchange at position c.1189C>T causing a stop codon (p.Q397X) in exon 9. Familial GTCS were reported in his brother and the paternal grandmother.Conclusion: Our study confirmed the role of SLC2A1 mutation carriers in EOAE and demonstrated that SLC2A1 do not seem to play a major role in CAE and JAE. Since ketogenic diet is a well known treatment option in GLUT-1-deficiency, pediatricians as well as neurologists may revisit the age of onset in patients diagnosed with absence epilepsies.