SQ-BSE developed, in addition to spongiform changes and astrogliosis, a complex proteinopathy with severe accumulations of PrPTSE, hyperphosphorylated tau (p-tau), ubiquitin, and α-synuclein but without the beta-amyloid (Aβ) protein typical of Alzheimer’s disease. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.