What genetic abnormality is primarily associated with Down Syndrome?

Down Syndrome is primarily associated with an additional chromosome 21, which results in a condition known as trisomy 21. This genetic abnormality occurs when there is an error in cell division called nondisjunction, leading to an individual having three copies of chromosome 21 instead of the typical two.

This extra genetic material disrupts normal development and results in the characteristic features associated with Down Syndrome, including distinct physical traits, cognitive delays, and an increased risk of certain medical conditions. Understanding the genetic basis of Down Syndrome is crucial for diagnosis and potential interventions, making this information particularly relevant in clinical and educational settings.

The other options listed involve different chromosomes or types of genetic abnormalities that do not apply to Down Syndrome, which is specifically linked to the third copy of chromosome 21. This clarity on the genetic aspects helps in recognizing the unique features and needs of individuals with Down Syndrome.