MAPT and Alzheimer disease: Furthermore, a recent transcriptomic analysis of transposable elements (TE) in 3Rtau, 4Rtau and 3R/4Rtau overexpressing immortalized human neurons found expression patterns in 3R/4Rtau expressing neurons more closely mimic the TE expression patterns in human AD than either tau isoform alone (Grundman et al., 2021).