WT1 and Wilms tumor: WT1 genotype–phenotype correlations exist with whole-gene deletions at 11p13 associated with WAGR [2], intron 9 splice site point mutations associated with FS [3], exon 8 or 9 zinc finger dominant-negative missense mutations associated with DDS [4], and nonsense mutations causing partial kidney or gonadal developmental defects such as isolated Wilms tumor or nephrotic syndrome [5].