Familial acute necrotizing encephalopathy (ANE) is a rapidly progressive encephalopathy that can occur after common viral infections at different stages of life. The clinical findings of 2 siblings diagnosed with ANE were shared and the whole-exome-sequencing study of the index case was performed. It was confirmed by the Sanger method. We found the RANBP2 gene p.I656V variant homozygous in the index case. We found the variant in the parents as heterozygous. We argue that biallelic mutations in the RANBP2 gene may result in ANE with early onset and severe prognosis by increasing penetrance.

Acute necrotizing encephalopathy (ANE) is a rapidly progressive encephalopathy occurring in otherwise healthy children after common viral infections. The condition presents as a spectrum of symptoms ranging from infections to seizures and coma, with the potential to cause long-term neurocognitive impairment or death. Familial and recurrent ANE is referred to as ANE1. A four-generation Chinese family with ANE1 was recruited for genetic analysis. A novel missense variation, c.9041A > G, p.(Glu3014Gly) in RANBP2 was identified in this family. This study is the first to identify a novel variation in RANBP2 in a Chinese family with ANE1.

Acute necrotizing encephalopathy (ANE), a rare entity with unique clinical presentation, can be associated significant morbidity and mortality. The majority of ANE reported cases are sporadic. However, reports of extremely rare familial cases are scarce. Case Presentation. We described three cases, two siblings and their cousin, affected by ANE, all of them exhibiting RAN-binding protein 2 (RANBP2) gene mutation. They all presented with seizure and decreased level of consciousness. Unlike the siblings, the cousin eventually expired mainly due to the delay in diagnosis, resulting from late presentation of typical brain involvements of ANE in magnetic resonance imaging (MRI). The presented cases are the first reports of familial ANE in Iran. Attempt was made to raise awareness on this disease, because high clinical suspicion plays an important role in the early diagnosis and proper management of these patients.

Acute necrotizing encephalopathy (ANE) is a specific type of encephalopathy usually followed by febrile infection. It has an aggressive clinical course; however, it usually does not recur after recovery in cases of spontaneous ANE. Nevertheless, there are several studies reporting recurrences in familial ANE with RAN-binding protein 2 (RANBP2) mutation. There are few cases of familial ANE with RANBP2 mutation in Asian populations. A 21-month-old Korean boy who was previously healthy, presented with seizure following parainfluenza - a virus and bocavirus infection, followed by 2 recurrent seizure episodes and encephalitis after febrile respiratory illnesses. Meanwhile, his 3-year-old sister had focal brain lesions on neuroimaging studies when evaluated for head trauma. The siblings also had an older brother who presented status epilepticus after febrile respiratory illness at the age of 10 months old. Brain magnetic resonance imaging was performed to evaluate the seizure and neurologic symptoms. Imaging findings showed variable spectrum - from non-specific diffuse white matter injury pattern to typical "tricolor pattern" of the ANE on diffusion-weighted images. The other 2 siblings showed focal lesions in both external capsules and severe diffuse brain edema. Genetic tests identified a heterozygous missense mutation in the RANBP2 [c.1754C>T (p.Thr585Met)] in 2 siblings and their mother. Patients were treated conservatively with anticonvulsive agents, intravascular immunoglobulin, and steroids. Among the 3 siblings, 2 male siblings died from familial ANE, whereas the female sibling was asymptomatic. These cases highlight the radiological aspects of familial ANE with incomplete penetrance of the RANBP2 gene in 3 family members, showing variable involvements of the brain and natural history on magnetic resonance images. Radiologists should be aware of the typical and atypical imaging findings of familial ANE for prompt management of affected patients.