Studies have shown that GBA mutations are reliable predictors of dementia in PD patients (Liu et al., 2017; Phongpreecha et al., 2020), but no difference was found between PD patients with normal cognition and MCI (Phongpreecha et al., 2020), similar to this early-stage study, which may be partially related to the fact that the GBA penetrance in PD patients increases with age (Anheim et al., 2012; Gan-Or et al., 2019). Here, GBA1 is linked to dementia.