We present a 9-month-old male with acute rotavirus gastroenteritis who developed an acute encephalopathy with focal seizures and developmental regression. Magnetic resonance imaging showed bilateral striatal necrosis and raised glutarylcarnitine levels on tandem mass spectrometry of a (crisis) blood spot, and chromatography of organic acids revealed increased urinary excretion of dicarboxylic acid. Skin biopsy demonstrated a partial decrease in glutaryl-CoA dehydrogenase activity. The case was not typical for either rotavirus encephalitis/rotavirus-associated encephalopathy or for glutaric aciduria type I. The patient has developmental delay and continues to receive physiotherapy, speech therapy, and local developmental follow-up.