First report of glucose transporter 1 deficiency syndrome in Korea with a novel splice site mutation

Glucose transporter type 1 deficiency syndrome (Glut-1DS) is caused by autosomal dominant haplodeficiency or autosomal recessive with homozygous mutation of the glucose transporter 1 (SLC2A1) gene and is characterized by severe seizures, developmental delay, ataxia and acquired microcephaly. We describe the first known Korean patient with glucose transporter 1 deficiency syndrome, who had a novel mutation in the splice site. The patient began having intractable seizures at 4 days of age that initially presented as eye blinking and apnea, evolving into generalized tonic seizures. A lumbar puncture revealed low glucose concentration in the cerebrospinal fluid (CSF) in the setting of normoglycemia (blood glucose, 106 mg/dl; CSF glucose 21 mg/dl, and CSF to blood glucose ratio 0.20). The results of a 3-O-methylglucose uptake study in erythrocytes (RBC) revealed that glucose uptake reduced to 48% of his parents in the patient. The patient responded to a ketogenic diet that was initiated at 4 months of age and currently is on the modified Atkins diet (MAD) without seizures. He does not require antiepileptic medication. We diagnosed the first Glut-1 patient in Korea with a novel splice site mutation on the basis of clinical features, deficient glucose uptake and a mutation in the SLC2A1 gene.