IGF2 IS PARENTALLY IMPRINTED DURING HUMAN EMBRYOGENESIS AND IN THE BECKWITH-WIEDEMANN SYNDROME

The phenomenon of parental imprinting involves the preferential expres sion of one parental allele of a subset of chromosomal genes and has s o far only been documented in the mouse. We show here, by exploiting s equence polymorphisms in exon nine of the human insulin-like growth fa ctor 2 (IGF2) gene, that only the paternally-inherited allele is activ e in embryonic and extra-embryonic cells from first trimester pregnanc ies. In addition, only the paternal allele is expressed in tissues fro m a patient who suffered from Beckwith-Wiedemann syndrome. Thus the pa rental imprinting of IGF2 appears to be evolutionarily conserved from mouse to man and has implications for the generation of the Beckwith-W iedemann syndrome.