COL6A1 and rheumatoid arthritis: Analysis of RA versus OA tissue highlighted similar trends for higher COL1, COL3 and COL6 genes in RA compared to OA, with significantly higher COL1A1, COL6A1 and COL6A2 in RA, whilst COL14A1 expression was significantly lower in RA compared to OA (Appendix Fig. S7B,D,F,H).