Our demonstration of miR-1202 acting as an anti-oncomiR in myeloid cells along with its reduced expression in T21-haematopoietic tissues extends our understanding of leukaemia susceptibility in DS and could provide the missing link in the cooperative effects of T21 and acquisition of somatic GATA-1 mutations in TAM onset and AML-DS development. Here, GATA1 is linked to leukemia.