PON2 and rheumatoid arthritis: We identified three vitamin D associated genes that were differentially expressed between RA and non-RA patients: Growth arrest and DNA-damage-inducible protein 45 alpha (GADD45A) (FC = 1.47; p = 0.006), Nuclear Receptor Co-repressor 1 (NCOR1) (FC = 1,21; p = 0.005) and paraoxonases 2 (PON2) (FC = -1.37; p = 0.01).