Twelve participants were identified with a 2p24.3 microduplication that included the DDX1 locus but not MYCN, none of whom received a diagnosis of a childhood embryonal tumour.<h4>Interpretation</h4>We have shown that 2p24.3 microduplications that include MYCN predispose to childhood embryonal tumours and should be routinely assessed when WT or neuroblastoma predisposition is suspected. Here, DDX1 is linked to embryonal neoplasm.