Infection-induced acute encephalitis-12 (IIAE12) is an autosomal recessive disorder characterized by episodic acute encephalopathy associated with infections and febrile illness. Patients present with neurologic symptoms in the first months or years of life, usually after normal early development. Brain imaging in the acute episodes shows restriction on diffusion-weighted imaging (DWI) and T2-weighted abnormalities in the periventricular and subcortical regions, which progresses to cavitation of previously affected areas. The long-term outcome is highly variable, even within families, ranging from death to severe neurologic deficits to normal outcomes (Shashi et al., 2023). For a discussion of genetic heterogeneity of susceptibility to acute infection-induced encephalopathy, see 610551. [from OMIM]