Location of the WT1 gene mutations and their overlap with MRD detection areas. The location of the WT1 gene mutations detected in initial diagnosis and relapse childhood AML samples is schematically presented according to the exon structure of the WT1 gene. Two areas of mutational hotspots were identified in exon 7. Two pairs of primer-probe combinations currently used for WT1-based MRD detection are also depicted in the figure and show overlap with the locations of the mutations.