A definite diagnosis of AD is only possible by the histopathological detection of its characteristic changes, the accumulation of extra-cellularly aggregated Aβ in plaques and cerebral vasculature (cerebral amyloid angiopathy / CAA) and intracellular and neurit-ic deposition of hyperphosphorylated tau protein (NFTs, neuropil threads and neuritic plaques), associated with loss of synapses and neurons in specific brain regions and loss of neuronal connectivity as a major cause of dementia (see [71, 72]). The gene discussed is MAPT; the disease is Alzheimer disease.