Final answer:
Presymptomatic testing for Huntington's Disease is conducted to determine if an asymptomatic individual with a family history of the disease carries the gene, indicating a risk of developing the condition.
Step-by-step explanation:
Presymptomatic testing for Huntington's Disease (HD) is performed on individuals who have a family history of HD but themselves show no symptoms at the time of testing. It's done to determine if they carry the gene responsible for HD and therefore have a heightened risk of developing the condition later in life. Huntington's Disease is an example of a hereditary disease for which carrier diagnosis tests are now available, similar to tests for cystic fibrosis, the Tay-Sachs diseases, and Duchenne muscular dystrophy.