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's syndrome is a chromosomal disorder caused by the presence of an extra copy of chromosome 21. This leads to physical and intellectual developmental delays.
Related terms
Trisomy 21: Trisomy 21 is another term for Down's syndrome, referring to the presence of three copies (instead of the usual two) of chromosome 21.
Non-disjunction: Non-disjunction is a genetic error that occurs during meiosis when chromosomes fail to separate properly. It can lead to conditions like Down's syndrome.
Intellectual disability: Intellectual disability: Individuals with Down's syndrome often experience some level of intellectual disability, which refers to limitations in cognitive functioning and adaptive skills.