Childhood-Onset Refractory Absence Epilepsy as a Presentation of Glucose Transporter 1 Deficiency Syndrome Type 2: A Case Report With a Diagnostic Challenge

Glucose transporter 1 (GLUT1) deficiency syndrome is a rare metabolic disorder caused by mutations in the SLC2A1 gene resulting in impaired glucose transport through the blood-brain barrier. The “classic” phenotype in children includes early-onset drug-resistant epilepsy, especially absence epilepsy, cognitive delay, movement disorders, and microcephaly. The ketogenic diet is the only treatment. We report a case of a 12-year-old girl who presented at the age of 11 years with daily absence seizures unresponsive to multiple antiseizure medications. Her poor therapeutic response raised suspicion for an underlying genetic etiology. Whole exome sequencing revealed a heterozygous mutation in the SLC2A1 gene, confirming a diagnosis of autosomal dominant GLUT1 deficiency syndrome type 2. The patient showed significant clinical improvement following the initiation of the ketogenic diet. This case highlights the importance of genetic evaluation in refractory absence epilepsy and the role of dietary therapy in GLUT1 deficiency.