Causes unknown hypotheses include abnormal neurophysiology in muscular layer including decreased nerve terminal number reduced nitrous oxide reduced number of interstitial cells of Cajal (IcC) a bacteria infection, such as Hellicobacter pylori genetic factors pyloroduodenal duplication cysts as cause of neonatal gastric outlet obstruction in case reportCauses ◼ unknown. hypotheses include ◼ abnormal neurophysiology in muscular layer including ◼ decreased nerve terminal number ◼ reduced nitrous oxide ◼ reduced number of interstitial cells of Cajal (ICC) ◼ bacteria infection, such as Helicobacter pylori ◼ genetic factors ◼ pyloroduodenal duplication cysts as cause of neonatal gastric outlet obstruction in case report