MAPT and early-onset autosomal dominant Alzheimer disease: Intracellular β-fibrils are also detectable by TEM as cytosolic bundles or aggregates in Alzheimer's disease (such as tau protein tangles) (Figure 1(a)), Parkinson's disease frontotemporal dementia, and dementia with Lewy bodies (α-synuclein and tau protein) and as nuclear aggregates, in Huntington's disease and other polyglutamine expansion diseases [1, 13].