MC1R and Parkinson disease: We also stratified participants with MC1R PD by genotype and found that although statistical significance was lost, single heterozygotes (n=139)(2.42; β diff=0.44 (−0.03 to 0.91) p=0.069), compound heterozygotes (n=64)(2.37; β diff=0.39 (−0.20 to 0.98) p=0.197), and homozygotes (n=17)(2.97; β diff=0.99 (−0.20 to 2.17) p=0.102) all had a nominally higher rate of change in MDS-UPDRS III compared to participants with sporadic PD (Table 3).