Loss of heterozygosity in non-tumoral tissue in two children with Beckwith-Wiedemann syndrome.

The Insulin-like growth factor II (IGF-II) gene has been analysed by Southern blotting in healthy and tumor tissue in two children with Beckwith-Wiedemann syndrome, using the enzymes, AvaII and SacI. Loss of heterozygosity was determined not only in the DNA of a nephroblastoma, but also in the healthy kidney, leukocytes and fragments of tongue removed for obstructive macroglossia. Allele loss therefore seems to be sufficient to provoke tumorigenesis in some tissues, but not in others.