MAPT and Alzheimer disease: Pathological features include senile plaques formed by the aggregation of amyloid-β (Aβ) in the brain, neurofibrillary tangles (NFTs) formed by the aggregation of hyperphosphorylated tau (p-tau), chronic inflammation, loss of synapses and neuronal death.1 Recent studies have shown that in many patients with AD but without senile plaques and NFTs in the brain, the morphology and function of synapses are already significantly degraded and some neurons have died.