CYP46A1 and early-onset autosomal dominant Alzheimer disease: This allowed us to use Cyp46a1−/− (6) and EFV-treated 5XFAD mice (an Alzheimer’s disease model) (53) as animal models with lacking and increased, respectively, CYP46A1 activity, and hence altered brain cholesterol turnover and sterol flux (6, 19, 23).