Recently, Kramann et al. reported that a small subset of pericytes (Gli1+PDGFRβ+CD73− cells; 0.2% of renal PDGFRβ+ cells), which displays mesenchymal stem cell features, is the major contributor of renal fibrosis through rigorous proliferation upon injury (Kramann et al., 2015). The gene discussed is PDGFRB; the disease is renal fibrosis.