Final answer:
Huntington's disease generally manifests around middle age, typically in the 40s, and children of an affected parent have a 50 percent chance of inheriting the disease.
Step-by-step explanation:
Average Age of Onset for Huntington's Disease (HD)
Huntington's disease (HD) is a neurodegenerative genetic disorder characterized by the wasting away of the nervous system. The average age of onset of clinical features typically occurs around middle age, with many people beginning to experience symptoms in their 40s. It is important to note that individuals who are heterozygous for the dominant Huntington allele (Hh) will inevitably develop HD. As the symptoms often arise after patients have had children, they may have already passed on the allele to their offspring, with each child having a 50 percent chance of inheriting the disorder.