Predictive and presymptomatic genetic testing is done to detect for gene mutations that can leave a person susceptible to disease later on in life. For this type of genetic testing, knowing the medical conditions that are present in your family history is important because it can help evaluate your risk for developing a certain disease. For example, a young female who has a family history of breast cancer would benefit from undergoing predictive and presymptomatic genetic testing before signs and symptoms appear (Lodder 1999). An evaluation from a geneticist, psychologist, psychiatrist, neurologist, and/or a social worker should be done to evaluate your need or reason for wanting to have a predictive genetic test done. The type of information presented during pretest counseling can include information about the disorder, the predictive test, possible psychological impacts, and the limitations and substantial elements of uncertainty that are linked to the test. The results of predictive and presymptomatic testing can help provide information for making decisions with your medical care (Borry 2008).
There is a substantial difference between a predictive genetic test and a traditional medical diagnosis. A person who undergoes a predictive genetic test is not a patient because there would be no need for medical care at the time that the genetic test is done. However, a predictive genetic test that shows a person has a gene mutation that could lead them to developing a certain genetic disease can help establish which early screening tests should be done. Some experts have argued that there should be a medical reason to carry out a predictive genetic test. Therefore, it has been stressed that the request for a test should be voluntary and come from a person who understands the implications of the test without any external pressure from family (Borry 2008).
Borry Pascal, Goffin Tom, Nys Herman, Diericky Kris. Predictive Genetic Testing in Minors for Adult-Onset Genetic Diseases. Mount Sinai Journal of Medicine 75:287-296, 2008.
Lodder L, Frets P, Trijsburg R, Meijers-Heijboer E, Klijn J, Duivenvoorden H, Tibben A, Wagner A, Van der Meer C A, Devilee P, Cornelisse C, Niermeijer N. Presymptomatic testing for BRCA1 and BRCA2: how distressing are the pre-test weeks? Journal of Medical Genetics 1999; 36(12): 906–913.