Which intellectual disability arises from genetic and chromosomal factors with an extra copy of chromosome 21?

• A. Intellectual Disabilities
• B. ADHD
• C. Language Impairments
• D. Down Syndrome

Answer: (D)

A genetic chromosomal condition where a person has an extra copy of chromosome 21 is Down syndrome. This occurs when cells carry an extra 21st chromosome, a situation called trisomy 21, which leads to intellectual disability along with characteristic physical features and developmental patterns.

The question asks which intellectual disability arises from genetic and chromosomal factors with an extra copy of chromosome 21. Down syndrome is the classic example of a chromosomal condition caused by an extra chromosome, so it is the best answer. Most cases result from nondisjunction during meiosis; sometimes a translocation or mosaicism can occur, but the common thread is three copies of chromosome 21 in the body's cells.

Other possibilities describe different issues: an overall category of intellectual disabilities doesn’t specify a chromosomal cause; ADHD is a neurodevelopmental condition with a distinct etiology; language impairments involve communication difficulties rather than a chromosomal anomaly.

In practice, supports for students with Down syndrome focus on language development, social interaction, and adaptive skills, tailored to each learner’s strengths and needs.