ARSA and Parkinson disease: Additionally, CTSB (pdiscovery = 9.47 × 10−5, preplication = 0.477) and ARSA (pdiscovery = 7.95 × 10−5, preplication = 0.153) were found to be significantly associated with PD onset in the discovery cohort but did not reach the p < 0.05 threshold in the replication cohort.