Previous studies have established a strong link between the progression of AD and the extent of synaptic dysfunction occurring in the early stages of the disease, prior to the formation of Aβ plaques and tau neurofibrillary tangles (Terry et al., 1991; Scheff et al., 2006; Shankar and Walsh, 2009; Koffie et al., 2011). The gene discussed is MAPT; the disease is Alzheimer disease.