FAU Advanced Health Assessment Practice Test

What is Down Syndrome primarily caused by?

1. A gene mutation

2. A chromosome defect

3. An environmental factor

4. A viral infection

The correct answer is: A chromosome defect

Down Syndrome is primarily caused by a chromosome defect, specifically the presence of an extra copy of chromosome 21, which is commonly referred to as Trisomy 21. This genetic condition arises when there is an error in cell division, known as nondisjunction, during the formation of reproductive cells. As a result, an individual inherits three copies of chromosome 21 instead of the usual two, leading to the characteristic features and developmental challenges associated with Down Syndrome. This understanding highlights the genetic basis of the condition rather than attributing it to a single gene mutation, environmental factor, or viral infection. While those factors can play roles in other health conditions or syndromes, Down Syndrome is distinctly linked to chromosomal abnormalities rather than other external influences or genetic changes.