RET and Hirschsprung disease: Indeed, to our knowledge the presence of structural variants in HSCR patients has never or rarely been reported for NRG1, SEMA3A/3D, and PHOX2B. Conversely RET involvement in HSCR does not seem to rely on the presence of CNVs but, interestingly, several gains and losses did co-occur with another RET defect in our sample, thus sustaining the hypothesis that more than one predisposing event is necessary for HSCR to develop.