jiHymas1, it sounds like you know way more about Huntington's Disease than I do. I wasn't talking about it specifically.  I understand that genetic testing can be used with respect to many conditions.  Here's what the US National Library of Medicine says about its benefits:

"Genetic testing has potential benefits whether the results are positive or negative for a gene mutation. Test results can provide a sense of relief from uncertainty and help people make informed decisions about managing their health care. 

"For example, a negative result can eliminate the need for unnecessary checkups and screening tests in some cases. 

"A positive result can direct a person toward available prevention, monitoring, and treatment options...."