CYP27A1 and dementia: The differentially methylated genes identified in our study that are known to be involved in ARA metabolism were CYP4F3, CYP4F22, CYP27A1, and CYP51A1. Among them, CYP4F3, CYP27A1, and CYP51A1 are involved in the phase 1 reaction (oxidation, reduction, and hydrolysis) of anti-dementia drug metabolism [33].