What is the primary cause of Down Syndrome?

What is the primary cause of Down Syndrome?

• A. An environmental factor leading to a mutation
• B. An extra copy of chromosome 21
• C. A deficiency of certain nutrients during pregnancy
• D. Inherited traits from parents

Answer: (B)

The primary cause of Down Syndrome is an extra copy of chromosome 21, a condition known as trisomy 21. This genetic anomaly occurs during cell division when an embryo receives an extra chromosome rather than the usual pair. As a result, individuals with Down Syndrome have three copies of chromosome 21, which leads to the characteristic physical and developmental features associated with the condition. The presence of this extra genetic material affects the individual's biological processes, leading to both the common physical traits associated with Down Syndrome as well as varying degrees of intellectual disability and developmental delays. The likelihood of this chromosomal abnormality often increases with maternal age, but the condition can occur in individuals born to parents of any age. This understanding distinguishes Down Syndrome from other potential factors affecting health during pregnancy, such as environmental factors or nutritional deficiencies, which do not directly cause the trisomy responsible for Down Syndrome. Additionally, while some traits can be inherited, Down Syndrome itself is primarily caused by this specific chromosomal abnormality rather than inherited genetic patterns.

The primary cause of Down Syndrome is an extra copy of chromosome 21, a condition known as trisomy 21. This genetic anomaly occurs during cell division when an embryo receives an extra chromosome rather than the usual pair. As a result, individuals with Down Syndrome have three copies of chromosome 21, which leads to the characteristic physical and developmental features associated with the condition.

The presence of this extra genetic material affects the individual's biological processes, leading to both the common physical traits associated with Down Syndrome as well as varying degrees of intellectual disability and developmental delays. The likelihood of this chromosomal abnormality often increases with maternal age, but the condition can occur in individuals born to parents of any age.

This understanding distinguishes Down Syndrome from other potential factors affecting health during pregnancy, such as environmental factors or nutritional deficiencies, which do not directly cause the trisomy responsible for Down Syndrome. Additionally, while some traits can be inherited, Down Syndrome itself is primarily caused by this specific chromosomal abnormality rather than inherited genetic patterns.