Figure 1.

Principal component analysis (PCA) of the RA and healthy control cohort. PCA revealed a group of individuals showing an outlier methylation profile. (a). Clustering analysis using the Partitioning Around Medoids implemented in M3C software supported the presence of two groups of individuals showing significantly different methylation profile. The x-axis indicates each of the clustering partitions evaluated (k=2 to 10); k=2 (orange dot) showed a highly significant evidence for clustering (P<0.001). (b). Principal components of the RA and control cohort showing the outlier group of individuals in the second PC, and color-coded based on the M3C k=2 class assignments.