The correct answer is Edwards Syndrome.

Edwards Syndrome is a genetic disorder caused by the presence of an extra copy of chromosome 18, also known as trisomy 18. This condition leads to severe developmental and physical abnormalities, including heart defects, growth retardation, and distinctive facial features. It is associated with a high mortality rate in infancy.

To clarify the other options:
- Patau Syndrome (Option 1) is caused by trisomy 13 (an extra chromosome 13).
- Down Syndrome (Option 3) results from trisomy 21 (an extra chromosome 21).
- Turner Syndrome (Option 4) is a sex chromosome disorder characterized by a missing or partial X chromosome (monosomy X), not a trisomy.

Therefore, the presence of an extra chromosome 18 specifically defines Edwards Syndrome.

Reference: Robbins Basic Pathology, 10th Edition, Chapter on Genetic Disorders/Page 256