Which syndrome is commonly associated with congenital heart defects alongside dysmorphic facial characteristics?

The correct answer is Down syndrome, which is also known as Trisomy 21. This chromosomal condition is characterized by a combination of physical and intellectual disabilities, including distinct dysmorphic facial features such as slanted eyes, a flat nasal bridge, and a protruding tongue.

Down syndrome is frequently associated with congenital heart defects, with about 40-50% of affected individuals having heart anomalies. Common types of congenital heart defects in individuals with Down syndrome include atrioventricular septal defects (AVSD) and ventricular septal defects (VSD). The presence of both the characteristic facial features and congenital heart defects makes Down syndrome a classic example in pediatric cardiology.

Other syndromes listed, such as Turner syndrome, Williams syndrome, and Noonan syndrome, also have associations with congenital heart defects and may present with specific dysmorphic features, but Down syndrome has the strongest and most recognized association between its distinct facial characteristics and cardiac abnormalities.