Fig. 2

Manhattan and quantile-quantile plots for the GWAS of extreme trajectories (a) and the multinomial GWAS of all five trajectories (b) Manhattan and quantile-quantile (Q–Q) plots of the results from the genome-wide association studies (GWAS) comparing (a) the two most extreme clusters, which correspond to the least and most impaired groups of persons with Parkinson’s disease, and (b) all five clusters identified from the longitudinal trajectories of patient-reported pain. Both sets of association tests adjusted for age, sex, and the first three multidimensional scaling (MDS) components. The Manhattan plots show \(-log10(p-value)\) on the y-axis and the chromosomal position of each genetic variant on the x-axis, with a dashed horizontal line indicating suggestive significance of \(2\times{10}^{-6}\). In the Q–Q plots, the observed versus expected p-values from the corresponding GWAS were plotted on the \(-log10\) scale. The observed genetic inflation factor was (a) \({\lambda}_{GC}=0.999\) for extreme cluster GWAS, and (b) \({\lambda}_{GC}=1.0409\) for the all cluster GWAS.