Various pathological hallmarks of AD include synaptic and neuronal loss, amyloid plaques primarily composed of the 42-residue hydrophobic β-amyloid peptide (Aβ) (Selkoe 2002), and neurofibrillary tangles (NFTs) composed of aggregates of hyperphosphorylated tau, which is a microtubule-associated protein (Kosik and Shimura 2005). This evidence concerns the gene MAPT and Alzheimer disease.