Jones-Tabah and colleagues used genetic data from the Fox Investigation for New Discovery of Biomarkers (BioFIND), the Harvard Biomarker Study (HBS), the Parkinson’s Progression Markers Initiative (PPMI), the Parkinson’s Disease Biomarkers Program (PDBP), the International LBD Genomics Consortium (ILBDGC), and STEADY-PD III Investigators, observing that rare variations in the CTSB gene have been associated with an elevated risk of PD [17]. Here, CTSB is linked to Parkinson disease.