Presymptomatic genetic testing of an untreatable disease raises clinical, ethical, legal and psychosocial questions. Investigations in specific disorders are needed to help in understanding the motivation for and the impact of genetic testing in the lives of persons at risk for these diseases. Here, we performed a longitudinal study to investigate the psychological consequences of presymptomatic genetic testing on people at risk for transthyretin-related familial amyloidotic polyneuropathy (TTR-FAP). The aim of the present study was to provide possible guidelines for genetic counselling and psychosocial support. Impact of Event Scale Revised (IES-R), Hospital Anxiety and Depression Scale (HADS) and SF-36 questionnaires were administered to 18 asymptomatic subjects before, immediately after communication of the genetic test result and after 3, 6 and 26 months. Our findings showed evidence of anxiety, depression, avoidance of the disease, and psychological distress, especially for women, including those with a negative genetic test result ("survivor guilt"). A psychological support has to be provided before and continued at long term after presymptomatic genetic testing for TTR-FAP in people with positive result as well as in those with negative result.