WT1 and Denys-Drash syndrome: In a previous study of AML, the WT1 mutations predominantly clustered in exon 7 (mostly frameshift mutations resulting from insertions or deletions) and less frequently in exon 9 (mostly substitutions), whereas in patients with Denys-Drash syndrome or Frasier syndrome, the majority of WT1 mutations were point mutations located either in Zn fingers 2 and 3 (exons 8 and 9) or, in cases of Frasier syndrome, in intron 9 [2].