BDNF and early-onset autosomal dominant Alzheimer disease: 16 showed that aberrantly high levels of miRNA‐206 in Alzheimer diseased brains are directly involved in the pathogenesis of Alzheimer disease by targeting the 3′ UTR of BDNF mRNA, suggesting that BDNF expression is post‐transcriptionally regulated by miRNA‐206. Therefore, we hypothesized that the long 3′ UTR variant of BDNF mRNA could be subjected to the differential regulation by specific miRNAs from the counterpart with a short 3′ UTR in a spatial‐specific manner.