What is a common feature of Trisomy 21 in newborns?

Trisomy 21, also known as Down syndrome, is commonly associated with various physical and health characteristics, with a higher risk of congenital heart defects being one of the most significant. Statistics indicate that approximately 40-50% of infants with Down syndrome are born with some form of congenital heart defect, such as atrioventricular septal defects or ventricular septal defects. This increased incidence is due to the chromosomal abnormalities that affect normal heart development during gestation.

Understanding the context of the other options aids in recognizing why the correct answer stands out. Low AFP levels are not typically associated with Trisomy 21; in fact, elevated levels might point towards the condition during prenatal screening. Increased birth weight is generally not characteristic of Trisomy 21; babies with this condition often have a lower overall birth weight due to the various health complications associated with the syndrome. Although delayed neurological development may occur in the long term, it is not a defining feature at birth, whereas congenital heart defects present immediate medical considerations. Hence, the heightened risk of congenital heart defects is a crucial and distinguishable characteristic of newborns with Trisomy 21.