The main clue related to the role of different variants is provided by the aforementioned retrospective and multicenter study published in 2022 (8); the study findings also suggest that there are no major differences in the cognitive decline after STN-DBS in PD-GBA1 carriers of severe or mild variants, while the carriers of risk variants could have a less degree of decline in the MDRS score than the carriers of mild or severe variants. The gene discussed is GBA1; the disease is Mental deterioration.