Alzheimer's disease (AD) is a devastating progressive neurodegenerative disease characterized by cognitive decline, brain atrophy due to neuronal and synapse loss, and the formation of two pathological lesions, extracellular amyloid plaques composed largely of amyloid-beta peptide (Aβ), and neurofibrillary tangles, intracellular aggregates of hyperphosphorylated tau protein [1, 2]. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.