CYP46A1 and Alzheimer disease: Considering the decreased level of neuron-specific cholesterol efflux protein CYP46A1 in the brains of AD patients [21] and the abnormal cholesterol deposition that occurs within neurons [6], we assessed the levels of CYP46A1, a neuronal cholesterol efflux protein, as well as its metabolite 24-OHC, in the brains of mice across each experimental group.