Pediatrics Genetics And Genetic Disorders cb32a48d Most common heart lesion in down syndrome: A Endocardial cushion defect B ASD with ostium secundum C VSD D Coarctation of aorta High-Yield Explanation a. Endocardial cushion defect(Ref: Nelson's 20/e p 610-614)Most common cardiac defect in Down syndrome is Endocardial cushion defect or Atrioventricular septal defect