Final answer:
A positive result of a genetic test for Huntington's disease does not offer preventive measures, while being positive for a deleterious BRCA mutation allows individuals to take proactive steps to reduce the risk of cancer.
Step-by-step explanation:
A positive result of a genetic test for Huntington's disease differs from being positive for a deleterious BRCA mutation in terms of the decisions that can be taken to prevent the onset of the disease. In the case of Huntington's disease, there are currently no known preventive measures or treatments to stop the progression of the disease. However, being positive for a deleterious BRCA mutation allows individuals to take proactive steps such as more frequent cancer screenings, preventive surgeries, and lifestyle changes to reduce the risk of developing breast or ovarian cancer.