Subjects carrying the RET -5AA, -1CC, 135AA or 2307GG genotype had a 17.75-fold (95% CI = 7.34-42.92), 10.89-fold (95% CI = 3.13-37.85), 13.61-fold (95% CI = 6.14-30.14) or 9.79-fold (95% CI = 4.28-22.43) elevated risk for the development of HSCR, compared with the counterpart wild genotype, respectively. This evidence concerns the gene RET and Hirschsprung disease.