MAPT and Alzheimer disease: Several neuropathological features are common to FBD, FDD and Alzheimer's disease (AD): amyloid deposition and neurodegeneration in the central nervous system (CNS), accumulation of complement proteins and their pro-inflammatory activation products, including iC3b, C4d, Bb, and C5b-9, neurofibrillary pathology and hyperphosphorylated tau [12], [13], [14].