MAPT and early-onset autosomal dominant Alzheimer disease: Phosphorylated Tau (pTau) is the major component of the neurofibrillary tangles that are commonly found in the brains of patients with Alzheimer's disease (AD) and many other tauopathy-related neurodegenerative diseases (Avila, 2006; Hanger et al., 2009; Hanger et al., 2002; Hanger et al., 1991).