Teaching NeuroImages: Subacute encephalopathy in a young woman with THTR2 gene mutation

A 21-year-old woman presented with coma after 5 days of fever, gait ataxia, and somnolence. Brain MRI showed lesions in medial thalami, caudate heads, and periaqueductal region (figure). Hyperlactatemia was present; serum thiamine levels were normal.