According to the “formaldehyde stress” hypothesis based on basic research, the abnormal accumulation of endogenous formaldehyde can cause abnormal change in proteins, resulting in neuronal responses such as tau hyper-phosphorylation (Lu J. et al., 2013), DNA damage (Lu Y. et al., 2013), reduced long-term potentiation (Tong et al., 2013a) and even cell death (Szende and Tyihák, 2010), followed by associated dysfunctions and neurodegenerative diseases (Chen et al., 2006; Tong et al., 2011, 2013b; Wang et al., 2012). The gene discussed is MAPT; the disease is neurodegenerative disease.