Familial acute necrotizing encephalopathy without RANBP2 mutation: Poor outcome.

Most childhood cases of acute necrotizing encephalopathy (ANE) involve neither family history nor recurrence. ANE occasionally occurs, however, as a familial disorder or recurs in Caucasian patients. A mutation of RAN-binding protein 2 (RANBP2) has been discovered in more than one half of familial or recurrent ANE patients. In contrast, there has been no report of this mutation in East Asia. Here, we report the first sibling cases of typical ANE in Japan, with poor outcome. DNA analysis of genes associated with ANE or other encephalopathies, including RANBP2 and carnitine palmitoyl transferase II (CPT2), indicated neither mutations nor disease-related polymorphisms. On literature review, recurrent or familial ANE without the RANBP2 mutation has a more severe outcome and greater predilection for male sex than that with the RANBP2 mutation. This suggests that there are unknown gene mutations linked to ANE.