Similarly, a case report demonstrated that a patient with gastric cancer who received chemotherapy developed delirium and hyperammonemia because the mutations of ORNT2 (ornithine transporter-2 for the urea cycle) and ETFA (electron transport flavoprotein alpha for fatty acid oxidation) exaggerated the response to the allopurinol challenge (Chu and Salzman, 2019), suggesting that uric acid metabolism dysfunction may contribute to delirium. This evidence concerns the gene SLC25A2 and delirium.