BWS cases are sporadic and are characterized by different imprinting defects including defects in the ICR1 region that results in loss of imprinting of Igf2 and hypermethylation of H19 and in most cases loss of methylation of the KvDMR1 that leads to gain of the non-coding Kcnq1ot1 transcript and loss of Kcnq1 and Cdkn1c expression [40]. This evidence concerns the gene IGF2 and Beckwith-Wiedemann syndrome.