September 11, 2026

@michaelokun

What resonates with me most about this paper is that it shifts the genetics conversation in Parkinson’s from simply “Who gets the disease?” to “Who progresses faster, and why?” Schumacher and colleagues report that common loss-of-function variants in MC1R, a gene many people associate primarily with pigmentation, were associated with about 30% faster motor progression in sporadic Parkinson’s, with an even larger effect in an independent replication cohort; importantly, the signal showed dose-response features and was driven particularly by worsening bradykinesia and orofacial function. The accompanying editorial makes several points I think are especially important: genetics that influence Parkinson’s risk may not be the same genetics that determine its trajectory; longitudinal off-medication measurements and independent replication make this study stronger than many traditional candidate-gene reports; and we should resist over-interpreting a single gene until these observations are confirmed in larger, multi-ancestry, genome-wide studies. Perhaps most exciting is where this could lead: combining genetics with the exposome and gene-environment interactions to understand not only why Parkinson’s develops, but why it moves faster in some people than others. That could ultimately help us provide better prognostic information, identify biologically meaningful subtypes, and enrich clinical trials with the people most likely to progress during the study window. https://jamanetwork.com/journals/jamaneurology/fullarticle/2853695