PHF1 and early-onset autosomal dominant Alzheimer disease: Different studies have shown that, during the mitotic division of different cell types, GA fragmentation is concomitant with a general phosphorylation of tau which is recognized by phosphorylation-dependent antibodies used to label neurofibrillary tangles in Alzheimer's disease (AD), such as PHF1, AT8, AT100, or AT180 (Pope et al., 1994; Preuss et al., 1995; Vincent et al., 1996; Illenberger et al., 1998; Preuss and Mandelkow, 1998; Delobel et al., 2002).