Although a stepwise increase in GCase activity was noticed between severe, mild, risk variant GBA1-NMC, and HC, no difference was detected between mild GBA1-PD and mild GBA1-NMC or between severe GBA1-PD and severe GBA1-NMC, indicating that GCase activity reflects genotype status but cannot be used as prognostic biomarker for PD conversion [28]. The gene discussed is GBA1; the disease is Parkinson disease.