GCase activity from all specimens was significantly reduced in GBA-PD patients (p < 0.001), compared to non-GBA-PD patients (GCaseRaw, 7.88 ± 1.45 nmol/h/mg vs. 10.29 ± 1.56 nmol/h/mg, p < 0.001; GCaseRatio, 59.47 ± 11.77% vs. 90.86 ± 16.13%, p < 0.001; GCaseDBS, 3.94 ± 1.43 μmol/h/L vs. 5.49 ± 1.75 μmol/h/L, p < 0.001) (Figures 1A–C). This evidence concerns the gene GBA1 and Parkinson disease.