Firstly, please be informed that even if you test positive for a particular disease in this DSGT, you are not certainly going to develop the disease. You simply have a higher probability than the average person of developing this condition as a result of your genetic conditions.
Also, having the necessary information allows you to take a targeted approach in prevention. In the event that you are unable to prevent the onset of the disease, you may at least delay its occurrence, thereby effectively prolonging your life to some extent. Furthermore, in some cases, precautionary measures can be taken to alleviate the severity of the disease, should the disease develop.