DCN and diabetic kidney disease: We performed a two‐sample Mendelian randomization analysis using cis eQTLs for decorin as instrumental variables and T1D/T1D with complications traits from the FinnGen GWAS study33 as outcomes (Figure 5B) and associated an eQTL‐regulating decorin transcription in fibroblasts with risk of diabetic nephropathy (Figure 5B).