Written by the Fiveable Content Team โข Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 examโขWritten by the Fiveable Content Team โข Last updated September 2025
Definition
Down Syndrome is a genetic disorder caused by the presence of an extra 21st chromosome. It's characterized by physical growth delays, characteristic facial features, and mild to moderate intellectual disability.
Related terms
Trisomy 21: This is another name for Down Syndrome because it involves three copies (tri) of chromosome 21 instead of the usual two.
Genetic Disorder: A disease or condition caused by abnormalities in an individual's genome. Down syndrome is an example of a genetic disorder.
Chromosome Abnormality: Any change in the normal structure or number of chromosomesโoften resulting in physical or mental abnormalities.