Indeed, it has been demonstrated that numerous oxysterols accumulate in the brain as AD progresses (e.g., 27-OHC, 25-OHC, 7α- and 7β-OHC, and 7-KC); conversely, the levels of 24-OHC drop dramatically in the late stages of the disease likely due to neuronal loss [19,65]. Here, CALCA is linked to Alzheimer disease.