The purpose of this project is to study the efficacy of triheptanoin oil in patients with GLUT1 deficiency syndrome.

The primary objective of the study is:

- to evaluate the capacity of triheptanoïn to improve the condition of patients with GLUT1-DS

The secondary objectives of the study are:

• to confirm the short-term safety of triheptanoïn therapy in patients with GLUT1-DS
• to evaluate the short-term effects of triheptanoïn treatment on motor function, autonomy, quality of life and clinical signs of patients with GLUT1-DS
• to evaluate the effect of triheptanoïn on brain energy metabolism using non-invasive 31P-MRS spectroscopy after activation of the occipital cortex in order to measure the levels of high-energy phosphates (such as ATP and phosphocreatine)

Inclusion Criteria:

• Mutation in SLC2A1 gene
• Age > 3 years
• Patient with history/frequency of seizures or movement disorders documented at least 3 months prior to the beginning of the study
• Covered by french social security
• Patients who freely agree to participate in this study and understand the nature, risks and benefits of this study and give their written informed consent. (In addition to the requirement for the consent of parents or the legal representative, adolescents can provide additional informed consent to participate in clinical trials)

Exclusion Criteria:

• Evidence of psychiatric disorder
• Attendant neurological disorder
• Comorbid medical condition that would render them unsuitable for the study, e.g. HIV, diabetes
• Pregnant or parturient or lactating women
• Unwillingness to be informed in case of abnormal MRI
• Failure to give written informed consent
• Unable to understand the protocol
• Unable to participate to the whole study
• Absence of signed informed consent
• Persons deprived of their liberty by judicial or administrative decision
• Person subject to an exclusion period for another research
• Subjects with exclusion criteria required by french law