Associations

Down's syndrome is associated with a higher incidence of a variety of congenital abnormalities, including:

• duodenal atresia in 10%
• Hirschsprung's disease in 3%
• other intestinal atresias

Up to 40% of cases are born with congenital heart defects, including:

• atrioventricular canal - the most common major defect
• ventricular septal defect
• patent ductus arteriosus
• atrial septal defect - ostium primum in 40%
• tetralogy of Fallot

Rarer associations include:

• annular pancreas
• increased incidence of sensorineural deafness