A newborn with confirmed trisomy 21 develops tachypnea and failure to thrive. Echocardiography is performed. Which cardiac lesion is MOST characteristically associated with Down syndrome?

• A Ostium secundum atrial septal defect
• B Coarctation of the aorta
• C Atrioventricular septal defect (endocardial cushion defect) ✓
• D Transposition of the great arteries

Explanation

The defect most characteristic of trisomy 21 is an atrioventricular septal defect, also called an endocardial cushion defect or complete atrioventricular canal defect. This results from failure of fusion of the superior and inferior endocardial cushions. Coarctation of the aorta is the classic association of Turner syndrome, not Down syndrome. Secundum ASD is a common isolated lesion but lacks the specific association, and transposition is linked with maternal diabetes.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.