Glucose Transporter 1 Deficiency: A Treatable Cause of Opsoclonus and Epileptic Myoclonus.

Background: Epileptic myoclonus in infancy is associated with various pathological conditions. In the absence of an identifiable central nervous system lesion, an underlying metabolic genetic cause is often suspected.

Patients: We describe two infants with glucose transporter 1 deficiency syndrome who presented with epileptic myoclonus. One infant presented with an electroclinical phenotype mimicking benign myoclonic epilepsy of infancy; the other infant had a novel mutation and presented with opsoclonus and epileptic myoclonus with a robust response to high-dose steroids. Both infants began the ketogenic diet after the diagnosis of glucose transporter 1 deficiency syndrome, with good yet variable treatment responses.

Conclusions: These infants demonstrate that an evaluation for glucose transporter 1 deficiency syndrome is warranted in patients presenting with an electroclinical picture compatible with benign myoclonic epilepsy of infancy as well as in patients with intractable epilepsy who demonstrate a significant response to steroid therapy.