ADAR and Alzheimer disease: Another study found a slight, but non-significant decline in ADAR2 mRNA levels within the hippocampus of patients with late-onset AD [21]; however, a significant increase in the expression of ADAR3 was also reported, which the authors speculate may be competitively inhibiting ADAR1 and ADAR2 binding to their target transcripts, thereby driving widespread hypoediting.