Epilepsy related to GLUT1 mutation and treated with ketogenic diet: a case series

Case presentation: We conducted a descriptive study of 4 cases with GLUT1 Deficiency (Glut1D) diagnosed in our service in the past 2 years. The diagnosis was established by: hypoglycorrhachia, clinical symptoms and SLC2A1 mutation. Our first patient, a 4-year-old boy, presented with developmental delay, hypotonia, myoclonic jerks and drop attacks at 11 months of age. MRI brain image showed bilateral hippocampal atrophy. Valproic acid and clobazam were started with partial seizures control. After introduction of ketogenic diet (KD), the patient achieved full seizure control, and anti-seizures drugs were discontinued. The second case is a 7-year-old boy, with seizures started at 3 months of age, characterized by generalized hypotonia and eye deviation. He had a delay of motor and language milestones and failed to achieve seizure control despite treatment with oxcarbazepine, valproic acid and levetiracetam. After the initiation of KD, a better seizure control and an improvement of muscle tone, speech and coordination were noticed. The third case is a 2-year-old girl, with tonic-clonic seizures started at 2 months of life. Diagnosis of Glut1D was established right after the first seizures, and she achieved an excellent control with levetiracetam and KD. Her development has been normal since. A 5-year-old girl is the fourth case, and presented with hypotonia, delay of speech and gait disturbance noticed around 1 year of age. Treatment with valproic acid and clobazam achieved partial control of seizures. Glut1D was diagnosed 3 years later, and better seizure control was noticed 1 year after the initiation of KD associated with levetiracetam.

Discussion: GLUT1 Deficiency is a rare and treatable metabolic encephalopathy. Around 80% of patients carry mutations in the SLC2A1 gene, located on chromosome 1. Transmission is autosomal dominant, with complete penetrance and most mutations are de novo. The syndrome is caused by a defect in the glucose transporter, GLUT1, located in the blood-brain barrier. The poor glucose transport is reflected by hypoglycorrhachia and manifests in many ways, from refractory seizures to developmental delay and movement disorder. The treatment of choice is a ketogenic diet, a high fat and low carbohydrate diet, that provides ketones as an alternative fuel to the brain.

Final comments: Early recognition of Glut1D is important to initiate KD and achieve adequate management.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
18 September 2023