qPCR analysis demonstrated that, compared with that in BLM‐SSc WT mice, the expression of fibrosis‐related genes (α‐SMA, Postn, Col1A1, Col1A3, Fn1, Timp1, Vimentin, and connective tissue growth factor, Ctgf) were downregulated in BLM‐SSc KO mice. The gene discussed is COL1A1; the disease is systemic sclerosis.