Consistently, data from myelodysplastic syndrome (MDS) and AML patient cohorts identified a number of tumour suppressor (TP53) and epigenetic mutations (DNMT3A, ASXL1, IDH1/2, and TET2) as early (first hit) initiating events preceding leukaemic transformation. The gene discussed is IDH1; the disease is acute myeloid leukemia.