Which of the following is characteristic of Edward's syndrome?

Edward's syndrome is characterized specifically by the presence of an extra chromosome 18, which is referred to as trisomy 18. This genetic condition results in a range of developmental and health issues due to the additional genetic material. Individuals with Edward's syndrome often present with distinctive physical features, including a small head, a jaw that is often smaller than normal (micrognathia), clenched hands, and a congenital heart defect, among other serious complications.

Each of the other options refers to different chromosomal abnormalities. Trisomy 21, known as Down syndrome, is associated with an extra chromosome 21. Trisomy 13, also known as Patau syndrome, involves an extra chromosome 13. The deletion of chromosome 7q is a specific chromosomal deletion that is not directly related to any of these syndromes but can lead to various genetic disorders. Understanding these distinctions is crucial in the context of genetic syndromes associated with specific chromosomal abnormalities.