WT1 and Nephroblastoma: Conversely, Japanese children with bilateral Wilms tumors instead were found to have a higher rate of WT1 mutations—among the 355 children analyzed in the JWiTS group, the WT1 mutation was found in 78% of those with bilateral Wilms tumors [93], which is significantly higher than observed in their Caucasian counterparts with bilateral Wilms tumors (17 to 38%) [61].