Acute Necrotizing Encephalopathy: 2 Case Reports on RANBP2 Mutation

Abstract

Infection-induced acute encephalopathy 3 (IIAE3) is an autosomal dominant disease resulting from a pathogenic variant in the RANBP2 gene. IIAE3 results in the susceptibility to the recurrence of acute necrotizing encephalopathy (ANE1) which presents as bilateral symmetric thalamic, midbrain and/or hindbrain lesions that typically develops within 1-4 days post-acute viral infection, commonly occurring before age 6.^1-6 These case reports highlight a retrospective analysis of clinical data and radiographic studies on 2 ANE1 cases from our institution. The novel p.Leu450Phe variant of the RANBP2 gene was analyzed using in silico algorithms (PolyPhen-2, SIFT, Mutationtaster) which suggests the p.Leu450Phe variant is probably deleterious.⁷ An expansion of documented ANE1 case presentations and clinically significant RANBP2 gene mutations has the potential to improve long term outcomes if more informed therapeutic decision making can be achieved.

Keywords: EEG; RANBP2 mutation; genetics; neuroimaging; pediatrics; seizure; status epilepticus.

Figure 1.

First patient’s follow-up MRI showing cystic encephalomalacia in bilateral medial thalamus (A) and pons (B). Second patient’s DWI MRI showing subtle increased signal in bilateral hippocampus (C) and thalamus (D), and T2 coronal (E) and FLAIR axial showing increased signal in bilateral thalamus (F).