[P1-30] Analysis of RANBP2 gene variants in Acute Necrotizing Encephalopathy
Acute necrotizing encephalopathy (ANE) is prevalent in East Asians, and non-recurrent and sporadic in the vast majority of cases. In contrast, recurrent and familial acute necrotizing encephalopathy (ANE1) occurs exclusively in Caucasians. We analyzed the entire coding region of RANBP2, the causative gene of ANE1, in 39 Japanese patients with ANE. Written informed consents were obtained from all patients’ guardians. Until now, 4 missense variants in exon 12 and 14 have been reported in ANE1. None of Japanese ANE patients had these variants. We detected 177 bp deletion in exon 20 in one patient, inherited from the asymptomatic mother. A missense mutation in exon24 (c.8496C>G, p.Phe2790Leu) was detected in another patient. Population frequency database revealed that this variant was detected only in East Asia (allele frequency 0.001503). Two patients had exonic SNP (rs76352345 G>C, p.Leu272Phe; minor allele frequency, 0.03) in exon7, which is predicted as “deleterious” in SIFT. These results showed that genetic background was different between ANE and ANE1. However, rare variants in RANBP2 may be a genetic risk factor in ANE.