In summary, we have uncovered the mechanism that instructs methylation imprint establishment at the specific sequences of the H19/Igf2 ICR at the endogenous location in fetal male germ cells, and by manipulating this mechanism, we generated an epigenetic SRS model resembling the majority of human SRS cases (2), in that it has partial stochastic ICR hypomethylation. This evidence concerns the gene IGF2 and Silver-Russell syndrome.