Questionnaire survey on the current status of ketogenic diet therapy in patients with glucose transporter 1 deficiency syndrome (GLUT1DS) in Japan

Objectives

We conducted a questionnaire survey on the efficacy and side effects of ketogenic diet (KD) therapy in patients with glucose transporter 1 deficiency syndrome (GLUT1DS) as well as issues associated with long-term KD therapy from the viewpoint of patients' families.

Subjects and methods

The subjects were 34 patients whose ages at the time of the survey ranged between 2 and 50 years (median, 11 years). The ages at the diagnosis ranged between 3 months and 48 years and 5 months (median, 4 years and 10 months), and KD therapy was started within 5 months in all patients.

Results

The types of KD therapies used were modified Atkins diet (MAD) in 18 patients (53%), MCT (medium chain triglyceride)-KD in 9 (26%), classic KD in 5 (15%), LGIT (low-glycemic index treatment) in 1 (3%), and unspecified diet in 1 (3%). Epileptic seizures improved by more than 90% in 17 patients, by 50–89% in 9, by less than 50% in 3, and an unknown percentage in 5. Neurological symptoms other than the epileptic seizures improved markedly, moderately, and mildly in 14, 5, and 7 patients, respectively, and did not improve in 2. The side effects of KD therapy were seen in 9 patients and it was subsequently discontinued in one.

Conclusions

The families of patients showed a high level of satisfaction with the efficacy of KD therapy for the neurological symptoms. However, in order to continue KD therapy for a long period of time, its tolerability needs to be improved.