Which statement correctly describes the age of onset for Huntington disease?

Which statement correctly describes the age of onset for Huntington disease?

• A. In infancy
• B. In the 30s to 40s
• C. In late 70s
• D. In adolescence

Answer: (B)

Huntington disease typically begins in midlife, most often showing up in the 30s to 40s. This timing reflects how the disease gradually unfolds as the brain, especially the striatum, loses neurons over years. The genetic basis is a CAG repeat expansion in the HTT gene; longer repeats tend to push the onset earlier, and this can even lead to earlier symptoms in later generations in a phenomenon known as anticipation. Onsets in infancy or adolescence are not typical, and a late onset in the 70s is quite uncommon. So, the statement describing onset in the 30s to 40s matches the usual clinical pattern.

Huntington disease typically begins in midlife, most often showing up in the 30s to 40s. This timing reflects how the disease gradually unfolds as the brain, especially the striatum, loses neurons over years. The genetic basis is a CAG repeat expansion in the HTT gene; longer repeats tend to push the onset earlier, and this can even lead to earlier symptoms in later generations in a phenomenon known as anticipation. Onsets in infancy or adolescence are not typical, and a late onset in the 70s is quite uncommon. So, the statement describing onset in the 30s to 40s matches the usual clinical pattern.