Encephalitis/encephalopathy, mild, with reversible myelin vacuolization

MMERV is an episodic acute reversible encephalopathy that occurs in children and is frequently associated with a trigger, such as a febrile illness. Affected individuals have impaired consciousness, delirious behavior, and/or seizures with lip smacking or eye deviation. These changes are associated with white matter lesions in the brain that often occur in the splenium of the corpus callosum, but may occur in surrounding areas. The acute phase of the disorder can be treated with steroids, and most patients make a full neurologic recovery between episodes with no sequelae (summary by Kurahashi et al., 2018). [from OMIM]