1. (noun) a congenital disorder caused by having an extra 21st chromosome; results in a flat face and short stature and mental retardation

• down syndrome
• down's syndrome
• mongolianism
• trisomy 21

1. (noun) a congenital disorder caused by having an extra 21st chromosome; results in a flat face and short stature and mental retardation

• birth defect
• congenital abnormality
• congenital anomaly
• congenital defect
• congenital disorder
• trisomy