LRRK2 and Parkinson disease: We analyzed PD progression in 802 PPMI participants (n=185 sporadic PD, 220 MC1R PD (139 heterozygotes, 64 compound heterozygotes, 17 homozygotes), 84 LRRK2 PD, 43 GBA PD, 187 MC1R + LRRK2 PD, and 83 MC1R + GBA PD) with 13 years of motor, non-motor, and cognitive assessments alongside 5 years of dopamine transporter imaging using linear mixed-effects models adjusted for potential confounders.