SYP and Alzheimer disease: Among them, six genes (SNAP25, KIF1A, GAP43, BSN, SYP, and NEFL) have been widely investigated in AD in previous studies (Tien et al., 2011; Agostini et al., 2019; Jia et al., 2020; Ren et al., 2020; Wang M. et al., 2020).