RT Journal Article SR Electronic T1 Raised risk of Wilms tumour in patients with aniridia and submicroscopic WT1 deletion JF Journal of Medical Genetics JO J Med Genet FD BMJ Publishing Group Ltd SP 787 OP 790 DO 10.1136/jmg.2007.051318 VO 44 IS 12 A1 Heyningen, Veronica van A1 Hoovers, Jan M N A1 Kraker, Jan de A1 Crolla, John A YR 2007 UL http://jmg.bmj.com/content/44/12/787.abstract AB Objective: The aim of this study was to determine if there is a significant difference in the risk of developing Wilms tumour between patients with submicroscopic and those with visible deletions of the WT1 tumour suppressor gene.Methods: To determine which subjects had WT1 deletions, high-resolution chromosomal deletion analysis of the 11p13 region was carried out in 193 people with aniridia. The rationale for this was that aniridia is caused by loss of function of one copy of the PAX6 gene, and although most patients with aniridia have intragenic mutations, a proportion has deletions that also include the nearby WT1 gene. Fluorescence in situ hybridisation (FISH) analysis of patients with aniridia identifies people with WT1 deletions regardless of whether they have Wilms tumour, allowing the deletion size to be correlated with clinical outcome.Results: Wilms tumour was not observed in any case without a WT1 deletion. Of subjects in whom WT1 was deleted, 77% with submicroscopic deletions (detectable only by high-resolution FISH analysis) presented with Wilms tumour compared with 42.5% with visible deletions (detectable by microscopy). This difference was significant.Conclusions: High-resolution deletion analysis is a useful tool for assessing the risk of Wilms tumour in neonates with aniridia. People with submicroscopic WT1 deletions have a significantly increased risk of Wilms tumour, and a high level of vigilance should be maintained in such cases.