Injection of rn-1 into AD model mice to inhibit the demethylation of histone K4 and K9 mediated by the LSD1 enzyme (Jarome and Lubin, 2013) can prevent the memory recognition of new objects in mice (Neelamegam et al., 2012), and LSD1 can combine with deacetylase (KDAC2) to form an inhibitory complex, which seriously affects the normal gene expression and cognitive function of AD mice (Gräff et al., 2012). The gene discussed is HDAC2; the disease is Alzheimer disease.