Mutations causing RUNX1 deficiency are detrimental for myeloid differentiation: heterozygous germline mutations result in a highly penetrant familial platelet disorder with a predisposition to AML [105] and somatic heterozygous RUNX1 mutations are recurrent in myelodysplastic syndromes and in AML with adverse outcome [106]. Here, RUNX1 is linked to myelodysplastic syndrome.