P94 – 2991: GLUT1-DS presenting as movement disorder in a male adolescent: Possible effect of late treatment with MAD

Abstract

Glucose transporter-1 deficiency syndrome (GLUT1-DS, OMIM 606777) is a treatable hereditary disorder of brain energy metabolism caused by heterozygous mutation in SLC2A1 gene on chromosome 1p34. Resulting deficient GLUT1 protein is responsible for impaired GLUT-1 mediated glucose transport into the brain clinically leading to a wide range of neurological symptoms. We report on a 15 years old male with genetically confirmed glucose transporter type 1 deficiency syndrome (GLUT1-DS; DYT9/DYT18). Developmental delay was already present before two years of age. Sudden episodes of exercise induced weakness without loss of consciousness were assumed to be myoclonic astatic epilepsy or atypical absences and therefore treated with valproinic acid and later with ethosuximide, both ineffectively. Hypoglycorrhachia and decreased CSF to blood glucose ratio found at the age of 14 years finally led to subsequent direct sequencing of SLC2A1 gene. Standard treatment in GLUT1-DS is ketogenic diet. Modified Atkins Diet (MAD) is an alternative ketogenic diet with the advantages preserving acceptable nutrition and obtaining compliance in adolescent patients. MAD has been described to improve movement disorder, seizures, alertness, cognitive abilities, and electroencephalography findings in GLUT1-DS in children. In our adolescent patient MAD was initiated in January 2015 to ameliorate symptoms such as movement disorder, paroxysmal exercise-induced dyskinesia, hypokinesia, tremor, rigor, spasticity and intellectual disability. In spite of abnormal EEG findings, symptomatic epilepsy has never been the leading symptom in this patient. We assume that even late treatment initiation of MAD in this adolescent patient could ameliorate movement disorder, cognitive function and EEG findings. Presenting this case report we will discuss actual literature concerning ketogenic diet in GLUT1-DS.