Diagnosis*	Prevalence (incidence per total births)	Findings
Meconium plug syndrome	One per 500 to 1,000	Meconium plugs
Cystic fibrosis–associated meconium ileus	One per 2,800	Abdominal distention at birth, cystic fibrosis
Hirschsprung’s disease	One per 5,0001,2	See Table 1
Anorectal malformation	One per 4,000 to 8,000	Anal fistula or an absent anus
Small left colon syndrome	Rare	Transition zone† at the splenic flexure
Hypoganglionosis	Rare	Transition zone†
Neuronal intestinal dysplasia	Rare	Megacolon, abnormal ganglion cells