MicroRNAs, circular RNAs, piwi-interacting RNAs, small interfering RNAs, and long non-coding RNAs have all been implicated in amyloid plaque formation and accumulation, tau hyperphosphorylation, neuroinflammation, oxidative stress, autophagy, and many other important pathophysiological processes in Alzheimer’s disease onset and progression. This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.