Patients with Beckwith-Wiedemann syndrome (BWS) have a risk of 7.5%to 10%o f developing childhood tumors, 60%of which are Wilms’tumors. Aberrant methylat ion of two distinct clusters of imprinted genes on chromosome 11p15 is detected in ～70%of BWS cases. Our aim was to determine associations between the imprint ing status of both imprinting clusters (BWSIC1/2) and the tumor incidence and ty pe. Methylation patterns of H19 and KCNQ1OT1 were collected in 114 patients with BWS with a clinical diagnosis. The patients were followed until 5 years of age, and tumor incidence and type were registered. A lower risk of developing childh ood tumors was found among patients with a methylation defect limited to BWSIC2 compared with other patients with BWS. No Wilms’tumors were found in this group , whereas in patients with a methylation defect limited to BWSIC1 Wilms’tumor w as the most common tumor. In addition to clinical factors indicative for a high tumor risk (hemihypertrophy, nephromegaly), methylation patterns discriminate be tween patients with BWS with a high and low tumor risk. It also is possible to p redict whether they are at risk of developing a Wilms’tumor. Epigenotyping of p atients is important to select the type of screening protocol to be proposed to these patients.
展开▼
