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Disease characteristics

Excerpted from the GeneReview: Glucose Transporter Type 1 Deficiency Syndrome
The phenotypic spectrum of glucose transporter type 1 deficiency syndrome (Glut1-DS) is now known to be a continuum that includes the classic phenotype as well as dystonia 9, dystonia 18, atypical childhood absence epilepsy, myoclonic astatic epilepsy, and paroxysmal non-epileptic findings such as intermittent ataxia, choreoathetosis, dystonia, and alternating hemiplegia. The classic phenotype is characterized by infantile-onset seizures, delayed neurologic development, acquired microcephaly, and complex movement disorders. Seizures begin before age two years in approximately 90% and later in approximately 10%. Several seizure types occur: generalized tonic or clonic, focal, myoclonic, atypical absence, atonic, and unclassified. The frequency, severity, and type of seizures vary among affected individuals and are not related to disease severity. Cognitive impairment, ranging from learning disabilities to severe intellectual disability, is typical. The complex movement disorder, characterized by ataxia, dystonia, and chorea, may occur in any combination and may be continuous, paroxysmal, or continuous with fluctuations in severity influenced by environmental factors such as fasting, fever, and intercurrent infection. Symptoms often improve substantially when a ketogenic diet is started.

Clinical features

  • Irritability
  • EEG abnormality
  • Reticulocytosis
  • Choreoathetosis
  • Hypoglycorrhachia
  • Cognitive impairment
  • Ataxia
  • Global developmental delay
  • Dystonia
  • Cerebral atrophy
  • Migraine
  • Dyskinesia
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