Recent whole genome and whole exome sequencing studies of ML-DS provide insight into the additional genetic events which co-operate with GATA1 mutations and trisomy 21 to further transform haematopoietic cells from a usually transient preleukaemic syndrome (TAM) to an acute leukaemia (ML-DS), which is inexorably fatal unless eradicated with chemotherapy [12••, 13]. This evidence concerns the gene GATA1 and transient myeloproliferative syndrome.