Which statement best describes the brain regions involved in Down syndrome as being most affected?

• A. Frontal cortex and temporal lobe
• B. Brainstem and cerebellum
• C. Occipital lobe and hippocampus
• D. Parietal lobes and thalamus

Answer: (B)

The most affected areas in Down syndrome are the cerebellum and brainstem. The cerebellum shows disproportionate hypoplasia in DS, meaning it’s smaller relative to the rest of the brain and has altered development. This underlies common motor findings like hypotonia, delays in motor coordination, balance problems, and gait issues. Brainstem involvement, though less discussed than the cerebellum, contributes to autonomic and reflex control and can influence overall tone and motor function as well. Together, these regions explain the prominent motor and coordination challenges seen early on in DS, making them the most characteristic sites of involvement among the options. Other regions listed may show some changes, but they do not exhibit the same consistent, primary impact as the cerebellum and brainstem in Down syndrome.