COL4A1 and systemic sclerosis: Levels of A20 mRNA were found to be reduced in SSc skin-derived fibroblasts (n = 6–10) in an independent transcriptome dataset11, while expression of tenascin-C, Col1a1, Col1a2, Col15a1, Col15a2 and Col4a1, and other profibrotic genes were elevated (Table 2).