EXT1 and rheumatoid arthritis: IPA of annotated transcripts showed similar activation of osteogenic-associated pathways such as roles of osteoblasts, osteoclasts, and chondrocytes in rheumatoid arthritis as well as the expression of typical osteogenic genes such as dlx5, tsc22d3, alpl, klf4, ext1, and stc1 in both datasets (Fig. 4a).