It has been well documented that the total tau and phosphorylated tau (p-tau 181 and p-tau 231) in the cerebrospinal fluid (CSF) are the main biomarkers for monitoring cortical axonal degeneration in AD (Hampel et al., 2010; Kandimalla et al., 2013; Head et al., 2016). The gene discussed is MAPT; the disease is Alzheimer disease.