GGT1 and argyrophilic grain disease: Due to selective isoform recruitment into neuropathological lesions in FTLD patients, tauopathies are now sub-categorized into the 3R tauopathy Pick’s disease (PiD) (Delacourte et al., 1996), the 4R tauopathies AGD, CBD, GGT, and PSP (Flament et al., 1991; Ksiezak-Reding et al., 1994), and the mixed 3R and 4R tauopathies Alzheimer’s disease (AD) and chronic traumatic encephalopathy (CTE) (Goedert et al., 1992; Hong et al., 1998; Schmidt et al., 2001).