FLT3 mutations are found in approximately 30–35% of newly diagnosed AML cases with either internal tandem duplications (FLT3-ITD) within the juxtamembrane domain coding region (exons 14 and 15, [12]) or missense mutations in the tyrosine kinase domain (FLT3-TKD) in the activation loop (exon20) [13]. The gene discussed is FLT3; the disease is acute myeloid leukemia.