Which of the following conditions is associated with chromosomal abnormalities?

• A. Cystic fibrosis
• B. Down syndrome
• C. Hemophilia
• D. Schizophrenia

Answer: (B)

Down syndrome is indeed associated with chromosomal abnormalities, specifically an extra copy of chromosome 21, which leads to the condition known as trisomy 21. This chromosomal condition results in a range of developmental and physical characteristics, including distinct facial features, intellectual disability, and increased risk for certain medical conditions. The presence of an extra chromosome is a clear indicator of a chromosomal abnormality, which fundamentally alters the normal genetic framework that governs a person's development and health.

In contrast, cystic fibrosis is caused by a mutation in a single gene, not a chromosomal abnormality. Hemophilia is also linked to genetic mutations related to specific genes that affect blood clotting rather than chromosomal number or structure. Schizophrenia, while having a genetic component, does not stem from identifiable chromosomal abnormalities but rather involves complex interactions of multiple genes and environmental factors. Thus, Down syndrome's direct link to an extra chromosome makes it the condition that fits with the concept of chromosomal abnormalities.