At the ages examined here, no significant increases in tau phosphorylation at CP13 (Ser202) or PHF1 (Ser396/404) were observed, in line with previous reports.30 However, an increased abundance of sarkosyl-insoluble tau was apparent in 12-month-old 3xTg-AD cortex (Figure 1b), as described previously.18, 19, 31, 32 The 3xTg-AD cortex also showed a progressive accumulation of total APP and Aβ1-42 relative to age-matched wild-type controls (Figure 2a), similar to that previously described by Oddo et al.19 Here, PHF1 is linked to Alzheimer disease.