Wilms tumor represents the most common cancer in BWS patients (Rump et al., 2005) with a high prevalence in combination with telomeric defects in H19/IGF2:IG-DMR -GOM and UPD subgroups (21.1% vs. 6.2%, respectively, P < 0.001); subjects with centromeric defects display a lower rate. The gene discussed is IGF2; the disease is Wilms tumor.