Alzheimer's disease is characterized by the presence of two histopathological hallmarks; the senile plaques or extracellular deposits mainly composed of amyloid-β peptide (Aβ) and the neurofibrillary tangles or intraneuronal inclusions composed of hyperphosphorylated tau protein [1]. The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.