PHF1 and tauopathy: In fact, postmortem diagnosis of tauopathies, including AD, is done by immunohistochemical staining of patients' brains with anti-tau phospho-specific antibodies such as AT8 (Ser202 and Thr205), AT180 (Thr231 and Ser235) and PHF1 (Ser396 and Ser404) (Figure 1A).