MAPT and early-onset autosomal dominant Alzheimer disease: Elevation of retrotransposon transcripts in Alzheimer's disease and progressive supranuclear palsy, a primary tauopathy, along with increased transposition in tau transgenic Drosophila12, 13, 14, 99, 100, 101, 102 suggested that retrotransposons are derepressed and may mobilize in human disease.