Genetic testing in subjects at risk for hereditary somatic diseases allows medical following and optimal prevention for mutation carriers. Genetic result announcement may have traumatic effects for these subjects and their families. We describe the experience of a multidisciplinary collaboration between the department of Consultation-Liaison Psychiatry and the department of Genetics of Hôpital Européen Georges-Pompidou, organized for rare vascular diseases and hereditary endocrine tumors. Liaison consultations are systematically provided before the test and after the confirmation of the result, with the aim to anticipate emotional consequences of the two potential genetic test results. The consultation-liaison psychiatrist not only meets the patient, but also participates in the conception of the testing procedure, from the decision to realize the test to the announcement of the result.