We found statistically significant higher CSF levels of SERPIN E1 in DLB vs. PD (total cohort: p = 0.019, Cohen’s d = −0.431; WT: p = 0.005, Cohen’s d = −0.505; GBA1: p = 0.148, Cohen’s d = −0.207) considering age at examination, disease duration and sex as covariates. This evidence concerns the gene GBA1 and Lewy body dementia.