To date, only two DNMT inhibitors, 5‐azacytidine (azacytidine, Vidaza®, Celgene, Summit, NJ, USA) and 2‐deoxy‐5‐azacytidine (decitabine, Dacogen®, MGI Pharma, Bloomington, MN, USA), both of which are nucleoside DNMT inhibitors, have been approved by the FDA to treat myelodysplastic syndrome (MDS). The gene discussed is DNMT1; the disease is myelodysplastic syndrome.