ADARB2 and Alzheimer disease: In addition, editing of several genes, including GRIA2, GRIA4, GRIK1, and GRIK2, is significantly reduced in the hippocampal tissues of patients with late-onset AD (LOAD) who also have upregulated ADAR3 transcript levels, suggesting ADAR3 could function as a negative regulator of RNA editing in LOAD (21).