Adult nonketotic hyperglycinemia (NKH) crisis presenting as severe chorea and encephalopathy.

We report on a patient with mild episodic nonketotic hyperglycinemia (NKH) on valproate who developed episodes of encephalopathy and chorea provoked by a fever and protein loading. After treatment with sodium benzoate and dextromethorphan, the patient's encephalopathy resolved and her chorea improved. The importance of this case is in recognizing this rare syndrome, which may present in the adult population.