APP and Alzheimer disease: Neuronal cell loss, neurofibrillary tangle (insoluble twisted fibers consisting primarily of the altered Tau protein) deposition inside cell, formation of Amyloid β (Aβ) (39-to-43 peptide originating from the sequential enzymatic cleavage of the larger trans-membrane protein called Amyloid Precursor Protein) plaque in the spaces among neurons and in the walls of blood vessels are microscopic features of AD (Wisniewski and Frackowiak, 1998[98]).