It seems that PNPLA3 mutant protein induces liver fibrosis by acting on hepatic stellate cells and not on other fibrogenic cells involved in later stages of fibrosis, thus explaining the interest in studying patients in whom the mechanisms of fibrosis are already activated, irrespective of disease stage (Pingitore et al., 2016). This evidence concerns the gene PNPLA3 and Hepatic fibrosis.