PTCH1 and Hirschsprung disease: With all these lines of evidence, we tried to determine whether genetic variants of RET, ARHGEF3 and CTNNAL1 have an impact on the risk of Hirschsprung disease, and by recruiting 1015 subjects and 38 polymorphisms within these three genes, we further explored the potential interaction networks among RET, ARHGEF3, and CTNNAL1 and our previously studied GAL, GAP43, NRSN1, PTCH1, GABRG2 and RELN genes.