RPP25 and osteoarthritis: Using expression and methylation data of the same osteoarthritis-affected individuals in the same tissue, we identified such expression quantitative trait methylation (eQTM) effects at nominal significance (p < 0.05) for three genes (ALDH1A2, FAM53A, and RPP25) in low-grade cartilage and one gene (LTBP1) in high-grade cartilage (Figure 7C).