What genetic abnormality is associated with Cri-du-chat syndrome?

Cri-du-chat syndrome is primarily associated with a deletion in the short arm of chromosome 5, specifically denoted as 5p. This genetic abnormality results in a variety of developmental issues that are characteristic of the syndrome, including the distinctive high-pitched cry that resembles a cat, which is how the syndrome gets its name.

The deletion of chromosome 5p leads to a loss of genetic material that is crucial for normal development, particularly affecting cognitive and physical growth. Individuals may exhibit symptoms such as intellectual disability, delayed development, and various physical abnormalities.

The other options refer to different chromosomal abnormalities. Trisomy 21 is associated with Down syndrome, caused by an extra copy of chromosome 21. Trisomy 18 is linked to Edward syndrome, characterized by an extra chromosome 18. Deletion of chromosome 7q does not correspond to Cri-du-chat syndrome, as it pertains to other genetic conditions. Thus, the deletion of chromosome 5p is the specific abnormality tied to Cri-du-chat syndrome, making this the correct response.