## **Core Concept**
Edwards syndrome, also known as Trisomy 18, is a genetic disorder caused by an extra copy of chromosome 18. This condition leads to severe developmental delays, intellectual disability, and life-threatening medical problems. It is one of the most common trisomies, alongside Trisomy 21 (Down syndrome) and Trisomy 13 (Patau syndrome).

## **Why the Correct Answer is Right**
The correct answer, , corresponds to Edwards syndrome, which is characterized by the presence of an extra chromosome 18. This results in a trisomy condition (having three copies of the chromosome instead of the usual two). The syndrome is associated with severe intellectual disability, microcephaly, overlapping fingers, and rocker-bottom feet, among other clinical features. The mechanism behind Edwards syndrome is a nondisjunction event during meiosis, leading to the extra chromosomal material.

## **Why Each Wrong Option is Incorrect**
- **Option A:** This option does not correspond to Edwards syndrome. Without specifying, we can infer it's incorrect based on the correct answer provided.
- **Option B:** This option is incorrect because it does not accurately represent Edwards syndrome.
- **Option D:** Similarly, this option does not correctly identify Edwards syndrome.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl for Edwards syndrome is that it has a high mortality rate, with many affected individuals not surviving beyond infancy due to severe medical complications. The condition is also associated with a high risk of miscarriage. Clinicians should be aware of the characteristic physical anomalies and consider genetic testing for definitive diagnosis.

## **Correct Answer:** . Edwards syndrome