MC1R and Parkinson disease: The relatively high frequency of MC1R RHC variants in the PPMI cohort aligns with previous reports in other PD cohorts as well as a meta-analysis on the frequency of MC1R RHC variants in European populations, indicating a larger role for MC1R in PD biology than previously appreciated.13,15-20,35 Taken together with laboratory findings from our group and others, these results warrant validation in larger and more diverse populations, ideally incorporating quantitative neuromelanin imaging, and longitudinal biospecimens to quantify oxidative stress and peripheral melanin metabolism.