In particular, molecular subgroups associated with CDKN1C loss of function (CDKN1C mutations and IC2 epimutations) have a significantly higher frequency of exomphalos than in patients with pUPD or IC1 epimutations (associated with biallelic expression of IGF2), whereas the risk of Wilms’ tumour is higher in the latter two groups. This evidence concerns the gene IGF2 and Wilms tumor.