It is well-known that small mothers against decapentaplegic (SMAD) proteins function as important intracellular signaling molecules in TGF-β signaling and are only substrates for TGF-β intracellular kinase, which is the reason why SMADs are critically linked to the development of liver fibrosis 51. The gene discussed is TGFB1; the disease is Hepatic fibrosis.