Acute necrotizing encephalopathy (ANE) typically affects young, healthy children 
who develop rapid-onset severe encephalopathy triggered by viral infections. 
This disease is more commonly reported in Japan but occurs worldwide, although 
it remains under-recognized in Western countries. An autosomal dominant form, 
ANE1, was recently identified. We report the details of a 9-year-old Caucasian 
female who experienced recurrent ANE episodes at the ages of 9 months and 9 
years. Brain magnetic resonance imaging findings were characteristic of ANE 
during both episodes, although more extensive in the recent episode, which 
resulted in severe neurological sequelae; influenza A was identified on 
bronchoalveolar lavage during this episode. Interestingly, there was evidence of 
peripheral polyneuropathy during the recent episode, which has not previously 
been described in sporadic ANE. Both the patient and her mother, who had also 
had postviral polyneuritis in the past, harbour a mutation in Ran-binding 
protein 2 (RANBP2); this occurred de novo in the mother and confers genetic 
susceptibility to ANE. Our case suggests that recurrent disease and/or an 
expanded clinical phenotype raises the possibility of ANE1; positive family 
history, although supportive, is not necessary as the mutation can occur de 
novo. Increased awareness may lead to earlier recognition and better treatment 
options.