The aggregation of the proteins Tau, A-beta, alpha-synuclein, PrP, Huntingtin, and serpins, into assemblies of fibrillar nature is intimately associated to tauopathies, such as Alzheimer’s disease; synucleinopathies, such as Parkinson’s disease; spongiform encephalopathies, such as Creutzfeldt-Jacob disease; Huntington’s disease; and different forms of dementias. Here, SNCA is linked to early-onset autosomal dominant Alzheimer disease.