The DAO levels in the healthy controls, amnestic MCI, mild AD, and moderate to severe AD were 23.9 ± 11.2, 32.2 ± 10.8, 38.1 ± 14.4 and 41.4 ± 19.5, respectively (p < 0.001) (Table 1 and Fig. 1). The gene discussed is DAO; the disease is Alzheimer disease.