Previous studies examining the risk of PD in individuals with MC1R RHC variants have reported inconsistent results, with some finding an association between R151C, R160W, and PD risk, while others have not.13,15-20 Our finding that MC1R RHC variants are associated with accelerated motor decline indicates a role in disease course, even as evidence for their association with PD risk remains uncertain. This evidence concerns the gene MC1R and Parkinson disease.