The neuropathological and neurochemical hallmarks of Alzheimer's disease (AD) include: synaptic loss and selective neuronal cell death; decreases in markers for certain neurotransmitters; and abnormalities in neurons and their processes (neurofibrillary tangles comprised of Tau and dystrophic neurites) as well as in the extracellular space (cerebrovascular, diffuse, and neuritic plaques - composed predominantly of the amyloidogenic peptide Aβ) [1], [2]. The gene discussed is MAPT; the disease is Alzheimer disease.