Common variants in the RET promoter (rs10900296; rs10900297), at a SOX10 binding site in intron 1 (rs2435357), and in exon 2 (rs1800858; c.135G>A;p.A45A) have also been associated with Hirschsprung's disease, suggesting that common as well as rare variants might influence the occurrence of Hirschsprung's disease (17). The gene discussed is RET; the disease is Hirschsprung disease.