In line with these findings, phosphorylation of SMAD3 and expression of TGF‐β1 were greatly enhanced in C1 KO mice after kidney IRI (Figure 4F,G), indicating that TGF‐β/Smad3 signalling is a key pathway in renal fibrosis associated with C1orf54 deficiency in kidney. This evidence concerns the gene C1orf54 and renal fibrosis.