MAPT and Alzheimer disease: Co-presence of NFTs, neurodegeneration and memory impairment in animal (Andorfer et al., 2005; Ramsden et al., 2005) and human studies (Maccioni et al., 2001; Ghoshal et al., 2002) and a significant correlation between p-tau in cerebrospinal fluid (CSF) and the disease progression (Kandimalla et al., 2013), supported tau hypothesis as the other explanation for AD pathology.