Population variation in total genetic risk of Hirschsprung disease from common RET, SEMA3 and NRG1 susceptibility polymorphisms.

The risk of Hirschsprung disease (HSCR) is ∼15/100 000 live births per newborn but has been reported to show significant inter-individual variation from the effects of seven common susceptibility alleles at the RET, SEMA3 and NRG1 loci. We show, by analyses of these variants in 997 samples from 376 HSCR families of European ancestry, that significant genetic risk can only be detected at RET (rs2435357 and rs2506030) and at SEMA3 (rs11766001), but not at NRG1. RET rs2435357 also showed significant frequency differences by gender, segment length of aganglionosis and familiality. Further, in combination, disease risk varied >30-fold between individuals with none and up to 6 susceptibility alleles. Thus, these polymorphisms can be used to stratify the newborn population into distinct phenotypic classes with defined risks to understand HSCR etiology.