In the study of astrocyte calcium signaling in AD patients, the expression of inositol 1,4,5-trisphosphate receptor type 2 (ITPR2) (also known as IP3 receptor type 2 (IP3R2)), an intracellular calcium release channel, was decreased in the astrocytes in brains of AD patients55,56. Here, ITPR2 is linked to Alzheimer disease.