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Hyperekplexia-epilepsy syndrome

Disease definition

A rare, X-linked, syndromic intellectual disability disease characterized by neonatal hypertonia which evolves to hypotonia and an exaggerated startle response (to sudden visual, auditory or tactile stimuli), followed by the development of early-onset, frequently refractory, tonic or myoclonic seizures. Progressive epileptic encephalopathy, intellectual disability, and psychomotor development arrest, with subsecuent decline, may be additionally associated.


  • Synonym(s): -
  • Prevalence: <1 / 1 000 000
  • Inheritance: X-linked recessive 
  • Age of onset: Neonatal
  • ICD-10: G25.8
  • OMIM: 300607
  • UMLS: C1845102
  • MeSH: -
  • GARD: -
  • MedDRA: -
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