Trisomy 21, also known as Down syndrome, is a genetic condition caused by the presence of an extra copy of chromosome 21. This extra chromosome affects physical and intellectual development, leading to characteristic features such as a flat facial profile, slanted eyes, and a shorter stature. Individuals with Down syndrome may also experience varying degrees of learning difficulties. People with Trisomy 21 can lead fulfilling lives and often have strong social skills. Early intervention, including speech and physical therapy, can help improve their abilities. With support from family and the community, many individuals with Down syndrome achieve personal goals and contribute positively to society.