An extra chromosome 18 is responsible for which syndrome?

An extra chromosome 18 is responsible for Edwards syndrome, also known as trisomy 18. This genetic disorder arises when there is a third copy of chromosome 18 in an individual's cells, which leads to a variety of physical and developmental challenges. Individuals with Edwards syndrome often present with distinctive physical features, including a small head, a small jaw, and clenched fists, along with significant heart and kidney defects.

The condition is associated with a high rate of complications and a relatively short life expectancy, with many affected infants not surviving past their first year. This syndrome is distinct from other chromosomal disorders, such as Down syndrome, which is characterized by an extra chromosome 21, Klinefelter syndrome, which involves an extra X chromosome in males, and Turner syndrome, which is a condition affecting females who have only one X chromosome. Understanding these distinctions helps clarify the specific impact of chromosomal anomalies on human development and health.