MIR9-1 and Alzheimer disease: Interestingly, the hypermethylation in the promoter region of 6 of these miRNA genes (MIR9-1, MIR9-3, MIR181C, MIR124-1, MIR146B, and MIR451) is in agreement with previous data from literature that shows downregulation in AD brains of their corresponding transcripts (miR-9, miR-181c, miR-124, miR-146b, and miR-451).