RUNX1 and acute myeloid leukemia: In 1999, the autosomal dominant familial platelet disorder with propensity to develop acute myeloid leukemia (now known as RUNX1 Familial Platelet Disorder with Associated Myeloid Malignancies, RUNX1-FPDMM) was the first HHM to have its molecular basis elucidated, driven by heterozygous pathogenic RUNX1 variants (4).