Background: The contribution of genetic variability to clinical heterogeneity in Parkinson's disease is insufficiently understood. We aimed to investigate the effect of cumulative genetic risk on clinical outcomes.
Methods: In a single-center study of 336 patients we genotyped 19 independent susceptibility variants identified in genome-wide association studies of Parkinson's disease. We tested for association between a cumulative genetic risk score and 3 outcome measures: survival, time until progression to Hoehn and Yahr stage 3, and Unified Parkinson's Disease Rating Scale motor score severity.
Results: Genetic risk score was significantly associated with time from diagnosis to Hoehn and Yahr stage 3 in a Cox regression model (P = 0.010). We observed no clear association for the other outcomes.
Conclusions: We present results linking cumulative genetic risk to a motor outcome in Parkinson's disease. Our findings provide a valuable starting point for future large-scale efforts to map the genetic determinants of phenotypic variability.
Keywords: GWAS; Hoehn and Yahr; Parkinson's disease; genetics; progression.
© 2016 International Parkinson and Movement Disorder Society.