In murine models of renal fibrosis involving unilateral ureteral obstruction (UUO) and folic acid nephropathy, hydralazine ameliorated renal fibrosis by demethylating RASAL1, the gene encoding rasGAP-activating-like protein 1, which activates fibroblasts and induces renal fibrogenesis when its promoter is aberrantly methylated [20, 21, 23]. The gene discussed is RASAL1; the disease is renal fibrosis.