Down syndrome is a genetic condition where a person has three copies of chromosome 21 instead of the typical two copies. It causes delays in physical, intellectual, and language development. Common physical traits include a flat nasal bridge, upward slanting eyes, and a protruding tongue. While the extent can vary, most with Down syndrome have some degree of intellectual disability. Lifelong support is typically needed, but many live fulfilling lives. Early intervention, screening for common health issues, physical therapy, and skills development can help maximize potential.