Firstly, there is a class of proteins that have been found to be abnormally expressed in AD patients or AD animal models, including Deficiency in G protein‐coupled receptor‐5 (GRK5), Heat shock protein 27 (Hsp27), 3‐β‐Hydroxysteroid‐Δ‐24‐reductase (DHCR24), Sirtuin 6 (SIRT6), regulator of calcineurin 1 (RCAN1), Cystatin C, and beta‐2 adrenergic receptors (β2ARs). This evidence concerns the gene RCAN1 and Alzheimer disease.