The common polymorphism rs2435357 (previously termed RET+3:C/T, with an ancestral allele C and a derived mutation allele T) in the noncoding enhancer element MCS+9.7 (Multispecies Conserved Sequence located 9.7 kb from the ATG codon) in intron 1 of the RET gene is a HSCR (Hirschsprung Disease) susceptibility allele[4,5]. The gene discussed is RET; the disease is Hirschsprung disease.