GBA1 and Parkinson disease: In a retrospective analysis, the temporal trajectories of measured putaminal SBR values were modeled over a time period spanning 10 years during the premotor phase of PD from N = 367 sPDs, N = 72 LRRK2-PDs (G2019S), and N = 39 GBA1-PDs (N370S) from the PPMI registry.