Which heart defect is most common in individuals with trisomy 21 (Down syndrome)?

Which heart defect is most common in individuals with trisomy 21 (Down syndrome)?

• A. AVSD
• B. VSD
• C. PDA
• D. Tetralogy of Fallot

Answer: (A)

Down syndrome has a strong association with atrioventricular septal defects because of abnormal development of the endocardial cushions that form the atrioventricular septum. This defect, often called an AV canal defect, creates a shared AV junction with a primum ASD and an inlet-type VSD, frequently with a single common AV valve. Because of this developmental disruption, AVSD is the most common congenital heart defect seen in individuals with trisomy 21. Other defects like VSD, PDA, and Tetralogy of Fallot do occur but are less typical for Down syndrome.

Down syndrome has a strong association with atrioventricular septal defects because of abnormal development of the endocardial cushions that form the atrioventricular septum. This defect, often called an AV canal defect, creates a shared AV junction with a primum ASD and an inlet-type VSD, frequently with a single common AV valve. Because of this developmental disruption, AVSD is the most common congenital heart defect seen in individuals with trisomy 21. Other defects like VSD, PDA, and Tetralogy of Fallot do occur but are less typical for Down syndrome.