BACE1 and Alzheimer disease: Cognitive impairments, characteristic of AD, correlate closely with the loss of synapses and evidence suggests that excess amyloid-β (Aβ) causes synapse dysfunction by impairing synapse maintenance, at least in part, through causing dysfunction of Wnt signaling.2, 3 Compromised Wnt signaling may also be associated with AD through loss of blood-brain barrier (BBB) integrity4 and Aβ generation through β-secretase (BACE1) expression.5