In serum exosomes of AD patients, miRNAs (miR-15, miR-185-5p, and miR-342-3p), were downregulated, and as their predicted target, APP was abnormally elevated in the AD brains, while miRNA-mRNA interaction caused less miRNAs (miR-15, miR-185-5p, and miR-342-3p) which to be sorted into exosomes [63]. The gene discussed is APP; the disease is Alzheimer disease.