BACE1 and Alzheimer disease: The authors also showed that genetic variability in the miRNA binding domains in the 3′-UTR of BACE1 and in the mRNA binding regions of miR-29 did not significantly increase risk of AD, suggesting that BACE1 is not overexpressed in AD due to an inability to bind miR-29, but more likely because miR-29 is down-regulated.