LRRC15 and rheumatoid arthritis: Two of the 13 candidate genes differentially expressed in osteoblasts of RA, LRRC15 and AKAP12, were found to have consistent direction of expression in the synovial tissue of RA patients identified in four of the five RA array datasets (GSE7307, GSE55475, GSE77298, GSE55235, and GSE1919).