A rare genetic neurological disorder with characteristics of infantile or childhood onset of recurrent acute encephalopathic episodes with cerebellar and extrapyramidal involvement following febrile illnesses. During the episodes, patients typically show sudden onset of truncal ataxia, occasionally accompanied by lethargy and impairment of speech, as well as choreic and athetoid movements, seizures, loss of deep tendon reflexes and presence of pathological reflexes. Episodes last from day to weeks and may leave residual symptoms such as speech impairment and poor coordination. [from
SNOMEDCT_US]