SMARCA5 and Alzheimer disease: SMARCA5 is a circular RNA that has been shown to be associated with a variety of cancers (Miao et al. 2020; Tan et al. 2019; Tong 2020; Zhang et al. 2021); previous studies have shown that there is no significant difference in SMARCA5 methylation frequency between the young, the elderly, and the AD group.