In other fibrotic diseases, N‐butyldeoxynojirimycin (miglustat), an inhibitor of glucosylceramide synthase (GCS) exerts its therapeutic effect on pulmonary fibrosis through inhibition of nuclear translocation of Smad2/3 rather than through suppression of TGF‐β1‐induced Smad2/3 phosphorylation.138. This evidence concerns the gene SMAD2 and pulmonary fibrosis.