A birth defect involving an abnormal opening in the diaphragm which is a structure that assists breathing and keeps the abdominal organs from moving into the chest. The abdominal organs can protrude through this abnormal opening and restrict the growth of chest organs such as the lung and heart. The severity of the condition is variable depending on the size of the defect - some cases aren't diagnosed until adulthood. See also Diaphragmatic hernia, congenital