Frequency and heritability of WT1 mutations in nonsyndromic Wilms' tumor patients: a UK Children's Cancer Study Group Study.
OBJECTIVE
Constitutional WT1 mutations in patients with Wilms' tumor (WT) have specifically been associated with genitourinary abnormalities, such as cryptorchidism and hypospadias. We sought to ascertain the frequency and heritability of constitutional WT1 mutations in nonsyndromic WT patients.


METHODS
Constitutional DNA from 282 patients treated at seven United Kingdom Children's Cancer Study Group centers was screened for WT1 mutations using heteroduplex analysis. Bidirectional sequencing was used to confirm the mutation and to analyze the corresponding parental DNA samples.


RESULTS
Five different constitutional WT1 mutations were identified in six children. Mutations in four patients were confirmed to be de novo, and all five mutations are predicted to produce truncated protein. The WT1 mutation group had a young median age at diagnosis of 13.8 months, compared with 34.9 months in the group in whom no WT1 mutations were found; four were female and two were male; and all tumors were of favorable histology. The three tumors with known histologic subtype were stromal-predominant. Contrary to expectation, four of six mutations occurred in children with unilateral tumors without any associated genitourinary abnormality.


CONCLUSIONS
Constitutional WT1 mutations occur with a low frequency (2.1%; 95% CI, 0.8% to 4.6%) in nonsyndromic WT patients. Most mutations occurred in children with unilateral WT without associated genitourinary abnormalities, creating difficulties in identifying individuals with germline mutations on phenotype alone. Two factors that may indicate that an individual is carrying a germline WT1 mutation are an early age of onset and stromal-predominant histology of the WT.
Paediatric Oncology Unit, The Royal Marsden NHS Trust, Downs Rd, Sutton, Surrey, SM2 5PT United Kingdom.
Suzanne E
SE
Little
Sandra P
SP
Hanks
Linda
L
King-Underwood
Chris
C
Jones
Elizabeth A
EA
Rapley
Nazneen
N
Rahman
Kathy
K
Pritchard-Jones
D002675:Child, Preschool; D015331:Cohort Studies; D000013:Congenital Abnormalities / Q000235:genetics; D005260:Female; D005787:Gene Frequency; D016162:Genes, Wilms Tumor; D018095:Germ-Line Mutation; D006801:Humans; D007223:Infant; D007680:Kidney Neoplasms / Q000235:genetics*; D008297:Male; D009154:Mutation; D025721:WT1 Proteins / Q000235:genetics*; D009396:Wilms Tumor / Q000235:genetics*
D025721:WT1 Proteins