SEMA3A and Hirschsprung disease: The SNPs we decided to investigate are located in intron 1 of RET, SEMA3A, and NRG1. Although, all these SNPS have been described to increase the risk for HSCR (de Pontual et al., 2006, 2007), we were unable to find a significant correlation between them and the occurrence of HSCR in this subset of GOSHS patients and unaffected family members (t test, p = .526; Tables 3 and 4).