Cruchaga and colleagues suggested in their study that in late-onset AD, mutations in MAPT and GRN may be as common as mutations in ‘amyloid beta precursor protein’ (APP), ‘presenilin 1’ (PSEN1), and ‘presenilin 2’ (PSEN2), the classical gene mutations associated with familial AD [14]. Here, GRN is linked to Alzheimer disease.