[Patient without being ill? Benefit and risks of presymptomatic diagnosis].

: A steadily growing number of genetic disorders or for predispositions disease can already be identified prior to their clinical manifestation. Gene technology has a considerable impetus on the development of presymptomatic or preclinical testing. Using familial cancer as a model it will be shown that persons at risk can be protected from the severe consequences of their genetic traits and can be counselled with certainty with respect to their family planning. However, such hopes are accompanied by fears that this type of genetic analysis will be performed without appropriate genetic counselling, without accepted medical practices or without the necessary quality control and that the results may be misinterpreted or misused by third parties. Informing the medical profession and the public about presymptomatic testing is the best way to prevent such negative consequences.