EDNRB and Hirschsprung disease: Hitherto, numerous genetic studies have identified dozens of HSCR-associated genes, where the major ones include RET (ret proto-oncogene) and EDNRB (endothelin receptor type B); yet, all these genes cumulatively explain only less than 10% of HSCR cases [3,5,6], suggesting that additional genes with low penetrance may also be involved in the etiology of HSCR.