NTRK1 and Hirschsprung disease: We examined all common (>10% minor allele frequency) non-coding variants within a ~153kb locus surrounding the gene for receptor tyrosine kinase RET, which is most commonly mutated in Hirschsprung disease (HSCR or congenital aganglionosis), a form of functional intestinal obstruction in neonates (1 in 5,000 live births).