[Postinfectious family case of acute necrotizing encephalopathy caused by RANBP2 gene mutation]

Acute necrotizing encephalopathy is a rare neurologic disease most often triggered by a febrile viral event affecting an otherwise healthy infant. The clinical course is characterized by rapid deterioration of the neurological condition that often leads to coma and requires intensive care. The diagnosis is usually suggested by MRI, which shows symmetrical and focal necrotic lesions of thalami. Acute necrotizing encephalopathy has been linked in recent studies to an autosomal-dominant mutation of the gene for the protein RAN-binding protein 2.

We report three cases in siblings of Tunisian origin. Two of them presented with acute necrotizing encephalopathy at the age of 9 months in the immediate aftermath of a viral infection. The molecular study conducted in the family showed that both patients and their mother were carriers of the missense mutation gene RAN-binding protein 2.

Although the role of Ran BP2 protein is incompletely known, mutation of the RANBP2 gene causes rare, reversible central neurologic disorders. Suspected diagnosis is facilitated by MRI, which shows specific lesions of multifocal, symmetric involvement of the thalami, brainstem tegmentum, supratentorial white matter, and cerebellum. Due to the low frequency of the disease and its non-specific clinical presentation, the diagnosis of acute necrotizing encephalopathy is a major challenge, while preventative measures can be proposed in familial mutation.