The only systematic molecular investigation (KIT, RAS, FLT3, NPM1, JAK2) in this cytogenetic subgroup identified FLT3-ITD in 1/6 MDS at diagnosis later transforming to s-AML and KRAS-mutation in 1/7 MDS patients at the time of leukemic transformation. This evidence concerns the gene NPM1 and myelodysplastic syndrome.