A 7-year-old developmentally delayed girl with chorea and a glucose transporter type 1 (GLUT 1) deficiency syndrome is reported from Hospital Universitari Sant Joan de Deu, Barcelona, Spain, and University of Texas Southwestern Medical Centre, Dallas. At 5 years of age she presented with an abrupt flaccidity and loss of ambulation for several minutes, without loss of consciousness. Chorea and mental retardation were associated with paroxysmal ataxia, convergent strabismus, dysarthria, dystonia, and aggravated intellectual disability induced by fasting or exertion. MRI showed cerebral hypotrophy, especially occipital lobes, and enlarged ventricles. EEG showed mild diffuse slowing, maximal posteriorly. Blood glucose and lactate were normal, but CSF glucose and lactate were diminished. DNA sequencing revealed a sporadic, heterogeneous amino acid insertion in the GLUT 1 transporter that probably impaired blood-brain glucose flux. Treatment with the ketogenic diet was followed by brain growth and improved symptomatic outcome by 7 years of age. Intellectual deterioration was unaffected, remaining below the 5th percentile for age. 
COMMENT. Most patients with GLUT 1 deficiency syndrome present with epilepsy and deceleration of brain growth, and the above case is considered a novel phenotype. Whereas chorea and ataxia were controlled by treatment with the ketogenic diet, intellectual deterioration was not reversed.