MC1R and Parkinson disease: When stratifying participants with MC1R PD by penetrance, both participants with low penetrance r variants (n=150)(2.32; β diff=0.34 (−0.16 to 0.83) p=0.183) and participants with high penetrance R variants (n=102)(2.57; β diff=0.59 (0.08 to 1.11) p=0.025) had a higher rate of change in MDS-UPDRS III compared to participants with sporadic PD; however, only the difference for participants with high penetrance R variants reached statistical significance (Table 3).