The aim of this study was to describe the experiences of undergoing a presymptomatic genetic test for the hereditary and fatal Huntington's disease, using a case study approach. The study was based on 18 interviews with a young woman and her husband from the decision to undergo the test, to receiving the results and trying to adapt to them, which were analysed using a life history approach. The findings show that the process of undergoing a presymptomatic test involves several closely connected ethical and medical questions, such as the reason for the test, the consequences of the test results and how health-care services can be developed to support people in this situation.