Pathogenic mutations in FLT3 gene (particularly FLT3 internal tandem duplication—(ITD)- and tyrosine kinase domain—TKD-mutations) are not a frequent event in MDS, accounting for 0.5–2% of patients at diagnosis, but when present, they are associated with high transformation rate and poor survival outcomes in the majority of cases [67,68,69,70]. The gene discussed is FLT3; the disease is myelodysplastic syndrome.